WorldWideScience

Sample records for temperature-independent switching rates

  1. Level-ARCH Short Rate Models with Regime Switching

    DEFF Research Database (Denmark)

    Christiansen, Charlotte

    This paper introduces regime switching volatility into level- ARCH models for the short rates of the US, the UK, and Germany. Once regime switching and level effects are included there are no gains from including ARCH effects. It is of secondary importance exactly how the regime switching is spec...

  2. Slew Rate Induced Distortion in Switched-Resistor Integrators

    NARCIS (Netherlands)

    Jiraseree-Amornkun, A.; Jiraseree-amornkun, A.; Worapishet, A.; Klumperink, Eric A.M.; Nauta, Bram; Surakampontorn, W.

    2006-01-01

    Abstract—OPAMP-RC integrators built with linear resistors and capacitors can achieve very high linearity. By means of a switched resistor, tuning of the RC time-constant is possible via the duty-cycle of the clock controlling the switched resistor. This paper analyzes the effect of OPAMP slew rate

  3. Temperature-independent resistor for microelectronic circuits

    Science.gov (United States)

    Aegerter, S.; Libby, W. F.

    1970-01-01

    Heat treating insulating crystals in gaseous hydrogen atmosphere produce resistive device which is temperature-independent from 77 to 295 degrees K. Increasing the concentration of hydrogen within the crystal yields semiconductor, hybrid, and metallic conduction characteristics which are combined with a depletion layer at the surface.

  4. Enhanced temperature-independent magnetoresistance below the ...

    Indian Academy of Sciences (India)

    The film exhibits a large nearly temperature-independent magnetoresistance around 99% in the temperature regime below p. The zero field-cooled (ZFC) and field-cooled (FC) magnetization data at 50 Oe shows irreversibility between the ZFC and FC close to the ferromagnetic transition temperature c = 250 K. The ZFC ...

  5. Optical Switching and Bit Rates of 40 Gbit/s and above

    DEFF Research Database (Denmark)

    Ackaert, A.; Demester, P.; O'Mahony, M.

    2003-01-01

    Optical switching in WDM networks introduces additional aspects to the choice of single channel bit rates compared to WDM transmission systems. The mutual impact of optical switching and bit rates of 40 Gbps and above is discussed....

  6. Passive Classification of Wireless NICs during Rate Switching

    Directory of Open Access Journals (Sweden)

    Cherita L. Corbett

    2008-02-01

    Full Text Available Computer networks have become increasingly ubiquitous. However, with the increase in networked applications, there has also been an increase in difficulty to manage and secure these networks. The proliferation of 802.11 wireless networks has heightened this problem by extending networks beyond physical boundaries. We propose the use of spectral analysis to identify the type of wireless network interface card (NIC. This mechanism can be applied to support the detection of unauthorized systems that use NICs which are different from that of a legitimate system. We focus on rate switching, a vaguely specified mechanism required by the 802.11 standard that is implemented in the hardware and software of the wireless NIC. We show that the implementation of this function influences the transmission patterns of a wireless stream, which are observable through traffic analysis. Our mechanism for NIC identification uses signal processing to analyze the periodicity embedded in the wireless traffic caused by rate switching. A stable spectral profile is created from the periodic components of the traffic and used for the identity of the wireless NIC. We show that we can distinguish between NICs manufactured by different vendors and NICs manufactured by the same vendor using their spectral profiles.

  7. Passive Classification of Wireless NICs during Rate Switching

    Directory of Open Access Journals (Sweden)

    Beyah RaheemA

    2008-01-01

    Full Text Available Abstract Computer networks have become increasingly ubiquitous. However, with the increase in networked applications, there has also been an increase in difficulty to manage and secure these networks. The proliferation of 802.11 wireless networks has heightened this problem by extending networks beyond physical boundaries. We propose the use of spectral analysis to identify the type of wireless network interface card (NIC. This mechanism can be applied to support the detection of unauthorized systems that use NICs which are different from that of a legitimate system. We focus on rate switching, a vaguely specified mechanism required by the 802.11 standard that is implemented in the hardware and software of the wireless NIC. We show that the implementation of this function influences the transmission patterns of a wireless stream, which are observable through traffic analysis. Our mechanism for NIC identification uses signal processing to analyze the periodicity embedded in the wireless traffic caused by rate switching. A stable spectral profile is created from the periodic components of the traffic and used for the identity of the wireless NIC. We show that we can distinguish between NICs manufactured by different vendors and NICs manufactured by the same vendor using their spectral profiles.

  8. Anomalously temperature-independent birefringence in biaxial optical crystals

    International Nuclear Information System (INIS)

    Grechin, Sergei G; Dmitriev, Valentin G; Dyakov, Vladimir A; Pryalkin, Vladimir I

    2000-01-01

    Temperature-independent birefringence in a biaxial crystal was predicted theoretically and observed experimentally for the first time. The width of the plot against temperature (the range corresponding to the temperature independence of the birefringence) at a fundamental radiation wavelength of 632.8 nm in a KTP crystal 5.9 mm long was more than 160 0 C. (letters to the editor)

  9. Temperature-independent energy expenditure in early development of the African clawed frog Xenopus laevis

    International Nuclear Information System (INIS)

    Nagano, Yatsuhisa; Ode, Koji L

    2014-01-01

    The thermal dissipation of activated eggs and embryos undergoing development from cleavage to the tailbud stage of the African clawed frog Xenopus laevis was measured as a function of incubation time at temperatures ranging from T = 288.2 K to 295.2 K, using a high-precision isothermal calorimeter. A23187-mediated activation of mature eggs induced stable periodic thermal oscillations lasting for 8–34 h. The frequency agreed well with the cell cycle frequency of initial cleavages at the identical temperature. In the developing embryo, energy metabolism switches from embryonic to adult features during gastrulation. The thermal dissipation after gastrulation fit well with a single modified Avrami equation, which has been used for modeling crystal-growth. Both the oscillation frequency of the activated egg and the growth rate of the embryo strongly depend on temperature with the same apparent activation energy of approximately 87 kJ mole −1 . This result suggests that early development proceeds as a single biological time, attributable to a single metabolic rate. A temperature-independent growth curve was derived by scaling the thermogram to the biological time, indicating that the amount of energy expenditure during each developmental stage is constant over the optimal temperature range. (paper)

  10. A 600 VOLT MULTI-STAGE, HIGH REPETITION RATE GAN FET SWITCH

    Energy Technology Data Exchange (ETDEWEB)

    Frolov, D. [Fermilab; Pfeffer, H. [Fermilab; Saewert, G. [Fermilab

    2016-10-05

    Using recently available GaN FETs, a 600 Volt three- stage, multi-FET switch has been developed having 2 nanosecond rise time driving a 200 Ohm load with the potential of approaching 30 MHz average switching rates. Possible applications include driving particle beam choppers kicking bunch-by-bunch and beam deflectors where the rise time needs to be custom tailored. This paper reports on the engineering issues addressed, the design approach taken and some performance results of this switch.

  11. Survival behavior in the cyclic Lotka-Volterra model with a randomly switching reaction rate.

    Science.gov (United States)

    West, Robert; Mobilia, Mauro; Rucklidge, Alastair M

    2018-02-01

    We study the influence of a randomly switching reproduction-predation rate on the survival behavior of the nonspatial cyclic Lotka-Volterra model, also known as the zero-sum rock-paper-scissors game, used to metaphorically describe the cyclic competition between three species. In large and finite populations, demographic fluctuations (internal noise) drive two species to extinction in a finite time, while the species with the smallest reproduction-predation rate is the most likely to be the surviving one (law of the weakest). Here we model environmental (external) noise by assuming that the reproduction-predation rate of the strongest species (the fastest to reproduce and predate) in a given static environment randomly switches between two values corresponding to more and less favorable external conditions. We study the joint effect of environmental and demographic noise on the species survival probabilities and on the mean extinction time. In particular, we investigate whether the survival probabilities follow the law of the weakest and analyze their dependence on the external noise intensity and switching rate. Remarkably, when, on average, there is a finite number of switches prior to extinction, the survival probability of the predator of the species whose reaction rate switches typically varies nonmonotonically with the external noise intensity (with optimal survival about a critical noise strength). We also outline the relationship with the case where all reaction rates switch on markedly different time scales.

  12. Survival behavior in the cyclic Lotka-Volterra model with a randomly switching reaction rate

    Science.gov (United States)

    West, Robert; Mobilia, Mauro; Rucklidge, Alastair M.

    2018-02-01

    We study the influence of a randomly switching reproduction-predation rate on the survival behavior of the nonspatial cyclic Lotka-Volterra model, also known as the zero-sum rock-paper-scissors game, used to metaphorically describe the cyclic competition between three species. In large and finite populations, demographic fluctuations (internal noise) drive two species to extinction in a finite time, while the species with the smallest reproduction-predation rate is the most likely to be the surviving one (law of the weakest). Here we model environmental (external) noise by assuming that the reproduction-predation rate of the strongest species (the fastest to reproduce and predate) in a given static environment randomly switches between two values corresponding to more and less favorable external conditions. We study the joint effect of environmental and demographic noise on the species survival probabilities and on the mean extinction time. In particular, we investigate whether the survival probabilities follow the law of the weakest and analyze their dependence on the external noise intensity and switching rate. Remarkably, when, on average, there is a finite number of switches prior to extinction, the survival probability of the predator of the species whose reaction rate switches typically varies nonmonotonically with the external noise intensity (with optimal survival about a critical noise strength). We also outline the relationship with the case where all reaction rates switch on markedly different time scales.

  13. Polyaniline-based memristive microdevice with high switching rate and endurance

    Science.gov (United States)

    Lapkin, D. A.; Emelyanov, A. V.; Demin, V. A.; Erokhin, V. V.; Feigin, L. A.; Kashkarov, P. K.; Kovalchuk, M. V.

    2018-01-01

    Polyaniline (PANI) based memristive devices have emerged as promising candidates for hardware implementation of artificial synapses (the key components of neuromorphic systems) due to their high flexibility, low cost, solution processability, three-dimensional stacking capability, and biocompatibility. Here, we report on a way of the significant improvement of the switching rate and endurance of PANI-based memristive devices. The reduction of the PANI active channel dimension leads to the increase in the resistive switching rate by hundreds of times in comparison with the conventional one. The miniaturized memristive device was shown to be stable within at least 104 cyclic switching events between high- and low-conductive states with a retention time of at least 103 s. The obtained results make PANI-based memristive devices potentially widely applicable in neuromorphic systems.

  14. Scalable In-Band Optical Notch-Filter Labeling for Ultrahigh Bit Rate Optical Packet Switching

    DEFF Research Database (Denmark)

    Medhin, Ashenafi Kiros; Galili, Michael; Oxenløwe, Leif Katsuo

    2014-01-01

    We propose a scalable in-band optical notch-filter labeling scheme for optical packet switching of high-bit-rate data packets. A detailed characterization of the notch-filter labeling scheme and its effect on the quality of the data packet is carried out in simulation and verified by experimental...

  15. New measure selection for Hunt-Devolder semi-Markov regime switching interest rate models

    Science.gov (United States)

    Preda, Vasile; Dedu, Silvia; Sheraz, Muhammad

    2014-08-01

    In this paper we construct the minimal entropy martingale for semi-Markov regime switching interest rate models using some general entropy measures. We prove that, for the one-period model, the minimal entropy martingale for semi-Markov processes in the case of the Tsallis and Kaniadakis entropies are the same as in the case of Shannon entropy.

  16. Q FUNCTION AWARE OPTICAL PACKET SWITCH WITH LOW PACKET LOSS RATE

    Directory of Open Access Journals (Sweden)

    OMPAL SINGH

    2017-03-01

    Full Text Available Optical packet switching (OPS is a very promising technology for the next generation data transfer due to the very large bandwidth of the optical fiber. The success of the OPS relies heavily on design of the node architecture which supports comparatively larger buffering capacity without detiorating signal quality too much and it should provide very low packet loss probability with reasonably low average delay. In this paper, a design analysis of low complexity OPS node architecture is discussed along-with its advantages. The presented architecture support both fixed and variable length packets. The packets are stored in a single piece of fiber using the WDM technology. Physical layer analysis presented in this paper is to obtain the Q function (Bit Error Rate. Finally, the Monte Carlo simulation is done to obtain the packet loss. The average delay performance of the switch and effect of Q values on packet loss rates are discussed.

  17. Single Longitudinal Mode, High Repetition Rate, Q-switched Ho:YLF Laser for Remote Sensing

    Science.gov (United States)

    Bai, Yingxin; Yu, Jirong; Petzar, Paul; Petros, M.; Chen, Songsheng; Trieu, Bo; Lee, Nyung; Singh, U.

    2009-01-01

    Ho:YLF/LuLiF lasers have specific applications for remote sensing such as wind-speed measurement and carbon dioxide (CO2) concentration measurement in the atmosphere because the operating wavelength (around 2 m) is located in the eye-safe range and can be tuned to the characteristic lines of CO2 absorption and there is strong backward scattering signal from aerosol (Mie scattering). Experimentally, a diode pumped Ho:Tm:YLF laser has been successfully used as the transmitter of coherent differential absorption lidar for the measurement of with a repetition rate of 5 Hz and pulse energy of 75 mJ [1]. For highly precise CO2 measurements with coherent detection technique, a laser with high repetition rate is required to averaging out the speckle effect [2]. In addition, laser efficiency is critically important for the air/space borne lidar applications, because of the limited power supply. A diode pumped Ho:Tm:YLF laser is difficult to efficiently operate in high repetition rate due to the large heat loading and up-conversion. However, a Tm:fiber laser pumped Ho:YLF laser with low heat loading can be operated at high repetition rates efficiently [3]. No matter whether wind-speed or carbon dioxide (CO2) concentration measurement is the goal, a Ho:YLF/LuLiF laser as the transmitter should operate in a single longitudinal mode. Injection seeding is a valid technique for a Q-switched laser to obtain single longitudinal mode operation. In this paper, we will report the new results for a single longitudinal mode, high repetition rate, Q-switched Ho:YLF laser. In order to avoid spectral hole burning and make injection seeding easier, a four mirror ring cavity is designed for single longitudinal mode, high repetition rate Q-switched Ho:YLF laser. The ramp-fire technique is chosen for injection seeding.

  18. Transitions in genetic toggle switches driven by dynamic disorder in rate coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hang, E-mail: hangchen@mit.edu; Thill, Peter; Cao, Jianshu [Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2016-05-07

    In biochemical systems, intrinsic noise may drive the system switch from one stable state to another. We investigate how kinetic switching between stable states in a bistable network is influenced by dynamic disorder, i.e., fluctuations in the rate coefficients. Using the geometric minimum action method, we first investigate the optimal transition paths and the corresponding minimum actions based on a genetic toggle switch model in which reaction coefficients draw from a discrete probability distribution. For the continuous probability distribution of the rate coefficient, we then consider two models of dynamic disorder in which reaction coefficients undergo different stochastic processes with the same stationary distribution. In one, the kinetic parameters follow a discrete Markov process and in the other they follow continuous Langevin dynamics. We find that regulation of the parameters modulating the dynamic disorder, as has been demonstrated to occur through allosteric control in bistable networks in the immune system, can be crucial in shaping the statistics of optimal transition paths, transition probabilities, and the stationary probability distribution of the network.

  19. Transitions in genetic toggle switches driven by dynamic disorder in rate coefficients

    International Nuclear Information System (INIS)

    Chen, Hang; Thill, Peter; Cao, Jianshu

    2016-01-01

    In biochemical systems, intrinsic noise may drive the system switch from one stable state to another. We investigate how kinetic switching between stable states in a bistable network is influenced by dynamic disorder, i.e., fluctuations in the rate coefficients. Using the geometric minimum action method, we first investigate the optimal transition paths and the corresponding minimum actions based on a genetic toggle switch model in which reaction coefficients draw from a discrete probability distribution. For the continuous probability distribution of the rate coefficient, we then consider two models of dynamic disorder in which reaction coefficients undergo different stochastic processes with the same stationary distribution. In one, the kinetic parameters follow a discrete Markov process and in the other they follow continuous Langevin dynamics. We find that regulation of the parameters modulating the dynamic disorder, as has been demonstrated to occur through allosteric control in bistable networks in the immune system, can be crucial in shaping the statistics of optimal transition paths, transition probabilities, and the stationary probability distribution of the network.

  20. Dynamically Switching among Bundled and Single Tickets with Time-Dependent Demand Rates

    Directory of Open Access Journals (Sweden)

    Serhan Duran

    2012-01-01

    Full Text Available The most important market segmentation in sports and entertainment industry is the competition between customers that buy bundled and single tickets. A common selling practice is starting the selling season with bundled ticket sales and switching to selling single tickets later on. The aim of this practice is to increase the number of customers that buy bundles, which in return increases the load factor of the events with low demand. In this paper, we investigate the effect of time dependent demand on dynamic switching times from bundled to single ticket sales and the potential revenue gain over the case where the demand rate of events is assumed to be constant with time.

  1. Robust temperature change rate actuated valving and switching for highly integrated centrifugal microfluidics.

    Science.gov (United States)

    Keller, M; Czilwik, G; Schott, J; Schwarz, I; Dormanns, K; von Stetten, F; Zengerle, R; Paust, N

    2017-02-28

    We present new unit operations for valving and switching in centrifugal microfluidics that are actuated by a temperature change rate (TCR) and controlled by the rotational frequency. Implementation is realized simply by introducing a comparatively large fluidic resistance to an air vent of a fluidic structure downstream of a siphon channel. During temperature decrease at a given TCR, the air pressure inside the downstream structure decreases and the fluidic resistance of the air vent slows down air pressure compensation allowing a thermally induced underpressure to build up temporarily. Thereby the rate of temperature change determines the time course of the underpressure for a given geometry. The thermally induced underpressure pulls the liquid against a centrifugal counterpressure above a siphon crest, which triggers the valve or switch. The centrifugal counterpressure (adjusted by rotation) serves as an independent control parameter to allow or prevent valving or switching at any TCR. The unit operations are thus compatible with any temperature or centrifugation protocol prior to valving or switching. In contrast to existing methods, this compatibility is achieved at no additional costs: neither additional fabrication steps nor additional disk space or external means are required besides global temperature control, which is needed for the assay. For the layout, an analytical model is provided and verified. The TCR actuated unit operations are demonstrated, first, by a stand-alone switch that routes the liquid to either one of the two collection chambers (n = 6) and, second, by studying the robustness of TCR actuated valving within a microfluidic cartridge for highly integrated nucleic acid testing. Valving could safely be prevented during PCR by compensating the thermally induced underpressure of 3.52 kPa with a centrifugal counterpressure at a rotational frequency of 30 Hz with a minimum safety range to valving of 2.03 kPa. Subsequently, a thermally induced

  2. Importance of ventricular rate after mode switching during low intensity exercise as assessed by clinical symptoms and ventilatory gas exchange.

    Science.gov (United States)

    Brunner-La Rocca, H P; Rickli, H; Weilenmann, D; Duru, F; Candinas, R

    2000-01-01

    Automatic mode switching from DDD(R) to DDI(R) or VVI(R) pacing modes has improved dual chamber pacing in patients at high risk for supraventricular tachyarrhythmias. However, little is known about the effect of ventricular pacing rate adaptation after mode switching. We conducted a single-blinded, crossover study in 15 patients (58 +/- 21 years) with a DDD pacemaker who had AV block and normal sinus node function to investigate the influence of pacing rate adaptation to intrinsic heart rate during low intensity exercise. Patients performed two tests (A/B) of low intensity treadmill exercise (0.5 W/kg) in randomized order. They initially walked for 6 minutes while paced in DDD mode. The pacing mode was then switched to VVI with a pacing rate of either 70 beats/min (test A) or matched to the intrinsic heart rate (95 +/- 11 beats/min test B). Respiratory gas exchange variables were determined and patients classified the effort before and after mode switching on a Borg scale from 6 to 20. Percentage changes of respiratory gas exchange measurements were significantly larger (O2 consumption: -8.2 +/- 5.0% vs. -0.6 +/- 7.2%; ventilatory equivalent of CO2 exhalation: 5.3 +/- 4.9% vs. 1.5 +/- 4.3%; respiratory exchange ratio: 7.0 +/- 2.2% vs. 3.5 +/- 3.0%; end-tidal CO2: -5.7 +/- 2.9% vs. -1.8 +/- 2.7%; all P higher (mean increase on Borg scale: 1.6 +/- 1.9 vs. 1.1 +/- 1.8, P = 0.07) after heart rate unadjusted than after adjusted mode switching. Mode switching from DDD to VVI pacing is better tolerated and gas exchange measurements are less influenced if ventricular pacing rate is adjusted to the level of physical activity. Thus, pacing rate adjustment should be considered as part of automatic mode switch algorithms.

  3. A Three-State Markov-Modulated Switching Model for Exchange Rates

    Directory of Open Access Journals (Sweden)

    Idowu Oluwasayo Ayodeji

    2016-01-01

    Full Text Available Several authors have examined the long swings hypothesis in exchange rates using a two-state Markov switching model. This study developed a model to investigate long swings hypothesis in currencies which may exhibit a k-state (k≥2 pattern. The proposed model was then applied to euros, British pounds, Japanese yen, and Nigerian naira. Specification measures such as AIC, BIC, and HIC favoured a three-state pattern in Nigerian naira but a two-state one in the other three currencies. For the period January 2004 to May 2016, empirical results suggested the presence of asymmetric swings in naira and yen and long swings in euros and pounds. In addition, taking 0.5 as the benchmark for smoothing probabilities, choice models provided a clear reading of the cycle in a manner that is consistent with the realities of the movements in corresponding exchange rate series.

  4. Demand Response of a TCL population using Switching-Rate Actuation

    DEFF Research Database (Denmark)

    Totu, Luminita Cristiana; Wisniewski, Rafal; Leth, John-Josef

    2017-01-01

    the distribution of the TCLs individual states across the population. The distribution approach has two main advantages. It scales excellently since the computational requirements do not increase with the number of units, and it allows data from individual units to be used anonymously, which solves privacy......This work considers the problem of actively managing the power consumption of a large number of thermostically controlled loads (TCLs), namely a TCL population, and a case-study of household refrigerators. Control is performed using a new randomized actuation that consists of switching units...... on and off at given rates, while at the same time respecting the nominal constraints on each individual unit. Both the free and the controlled behavior of individual TCLs can be aggregated, making it possible to handle a TCL population as if it were a single system. The aggregation method uses...

  5. Differences in rates of switchbacks after switching from branded to authorized generic and branded to generic drug products: cohort study

    Science.gov (United States)

    Sarpatwari, Ameet; Dejene, Sara; Khan, Nazleen F; Lii, Joyce; Rogers, James R; Dutcher, Sarah K; Raofi, Saeid; Bohn, Justin; Connolly, John; Fischer, Michael A; Kesselheim, Aaron S; Gagne, Joshua J

    2018-01-01

    Abstract Objectives To compare rates of switchbacks to branded drug products for patients switched from branded to authorized generic drug products, which have the same active ingredients, appearance, and excipients as the branded product, with patients switched from branded to generic drug products, which have the same active ingredients as the branded product but may differ in appearance and excipients. Design Observational cohort study. Setting Private (a large commercial health plan) and public (Medicaid) insurance programs in the US. Participants Beneficiaries of a large US commercial health insurer between 2004 and 2013 (primary cohort) and Medicaid beneficiaries between 2000 and 2010 (replication cohort). Main outcome measures Patients taking branded products for one of the study drugs (alendronate tablets, amlodipine tablets, amlodipine-benazepril capsules, calcitonin salmon nasal spray, escitalopram tablets, glipizide extended release tablets, quinapril tablets, and sertraline tablets) were identified when they switched to an authorized generic or a generic drug product after the date of market entry of generic drug products. These patients were followed for switchbacks to the branded drug product in the year after their switch to an authorized generic or a generic drug product. Cox proportional hazard models were used to estimate hazard ratios and 95% confidence intervals after adjusting for demographics, including age, sex, and calendar year. Inverse variance meta-analysis was used to pool adjusted hazard ratios across all drug products. Results A total of 94 909 patients switched from branded to authorized generic drug products and 116 017 patients switched from branded to generic drug products and contributed to the switchback analysis. Unadjusted incidence rates of switchback varied across drug products, ranging from a low of 3.8 per 100 person years (for alendronate tablets) to a high of 17.8 per 100 person years (for amlodipine

  6. High-Sensitivity Temperature-Independent Silicon Photonic Microfluidic Biosensors

    Science.gov (United States)

    Kim, Kangbaek

    Optical biosensors that can precisely quantify the presence of specific molecular species in real time without the need for labeling have seen increased use in the drug discovery industry and molecular biology in general. Of the many possible optical biosensors, the TM mode Si biosensor is shown to be very attractive in the sensing application because of large field amplitude on the surface and cost effective CMOS VLSI fabrication. Noise is the most fundamental factor that limits the performance of sensors in development of high-sensitivity biosensors, and noise reduction techniques require precise studies and analysis. One such example stems from thermal fluctuations. Generally SOI biosensors are vulnerable to ambient temperature fluctuations because of large thermo-optic coefficient of silicon (˜2x10 -4 RIU/K), typically requiring another reference ring and readout sequence to compensate temperature induced noise. To address this problem, we designed sensors with a novel TM-mode shallow-ridge waveguide that provides both large surface amplitude for bulk and surface sensing. With proper design, this also provides large optical confinement in the aqueous cladding that renders the device athermal using the negative thermo-optic coefficient of water (~ --1x10-4RIU/K), demonstrating cancellation of thermo-optic effects for aqueous solution operation near 300K. Additional limitations resulting from mechanical actuator fluctuations, stability of tunable lasers, and large 1/f noise of lasers and sensor electronics can limit biosensor performance. Here we also present a simple harmonic feedback readout technique that obviates the need for spectrometers and tunable lasers. This feedback technique reduces the impact of 1/f noise to enable high-sensitivity, and a DSP lock-in with 256 kHz sampling rate can provide down to micros time scale monitoring for fast transitions in biomolecular concentration with potential for small volume and low cost. In this dissertation, a novel

  7. High repetition rate Q-switched Er3+-doped fiber ring laser

    DEFF Research Database (Denmark)

    Sejka, Milan; Poulsen, Christian; Shi, Yuan

    1993-01-01

    In this paper we present for the first time Q switched Er-doped fibre laser utilising a ring Fabry-Perot cavity......In this paper we present for the first time Q switched Er-doped fibre laser utilising a ring Fabry-Perot cavity...

  8. Lower switch rate in depressed patients with bipolar II than bipolar I disorder treated adjunctively with second-generation antidepressants

    NARCIS (Netherlands)

    Altshuler, LL; Suppes, T; Nolen, WA; Leverich, G; Keck, PE; Frye, MA; Kupka, R; McElroy, SL; Grunze, H; Kitchen, CMR; Post, R; Black, D.O.

    Objectives: The authors compared the switch rate into hypomania/mania in depressed patients treated with second-generation antidepressants who had either bipolar I or bipolar II disorder. Method: In a 10-week trial, 184 outpatients with bipolar depression (134 with bipolar I disorder, 48 with

  9. Power grid current harmonics mitigation drawn on low voltage rated switching devices with effortless control

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Hugo S.; Anunciada, Victor; Borges, Beatriz V. [Power Electronics Group, Instituto de Telecomunicacoes, Lisbon (Portugal); Instituto Superior Tecnico - Universidade Tecnica de Lisboa, Lisbon (Portugal)

    2010-01-15

    The great majority of the existing hybrid active power filter solutions is normally focused in 3{phi} systems and, in general, concentrates its domain of application in specific loads with deterministic behavior. Because common use grids do not exhibit these characteristics, it is mandatory to develop solutions for more generic scenarios, encouraging the use of less classical hybrid solutions. In fact, due to the widely use of switch mode converters in a great variety of consumer electronics, the problematic of mains current harmonic mitigation is no longer an exclusive matter of 3{phi} systems. The contribution of this paper is to present a shunt hybrid active power filter topology, initially conceived to work in 1{phi} domestic grids, able to operate the inverter at a voltage rate that can be lower than 10% of the mains voltage magnitude, even under nonspecific working conditions. In addition, the results shown in this paper demonstrate that this topology can, without lack of generality, be suitable to medium voltage (1{phi} or 3{phi}) systems. A new control approach for the proposed topology is discussed in this paper. The control method exhibits an extremely simple architecture requiring single point current sensing only, with no need for any kind of reference. Its practical implementation can be fulfilled by using very few, common use, operational amplifiers. The principle of operation, design criteria, simulation predictions and experimental results are presented and discussed. (author)

  10. Switching antidepressants

    African Journals Online (AJOL)

    depressive disorder, with response rates of 50-60%. Switching within or between classes of antidepressants is often required in patients with an insufficient response to SSRIs.12 Because they share a similar mechanism of action, the immediate substitution of one SSRI for another is probably the easiest switching option.

  11. Pseudospark switches

    International Nuclear Information System (INIS)

    Billault, P.; Riege, H.; Gulik, M. van; Boggasch, E.; Frank, K.

    1987-01-01

    The pseudospark discharge is bound to a geometrical structure which is particularly well suited for switching high currents and voltages at high power levels. This type of discharge offers the potential for improvement in essentially all areas of switching operation: peak current and current density, current rise, stand-off voltage, reverse current capability, cathode life, and forward drop. The first pseudospark switch was built at CERN at 1981. Since then, the basic switching characteristics of pseudospark chambers have been studied in detail. The main feature of a pseudospark switch is the confinement of the discharge plasma to the device axis. The current transition to the hollow electrodes is spread over a rather large surface area. Another essential feature is the easy and precise triggering of the pseudospark switch from the interior of the hollow electrodes, relatively far from the main discharge gap. Nanosecond delay and jitter values can be achieved with trigger energies of less than 0.1 mJ, although cathode heating is not required. Pseudospark gaps may cover a wide range of high-voltage, high-current, and high-pulse-power switching at repetition rates of many kilohertz. This report reviews the basic researh on pseudospark switches which has been going on at CERN. So far, applications have been developed in the range of thyratron-like medium-power switches at typically 20 to 40 kV and 0.5 to 10 kA. High-current pseudospark switches have been built for a high-power 20 kJ pulse generator which is being used for long-term tests of plasma lenses developed for the future CERN Antiproton Collector (ACOL). The high-current switches have operated for several hundred thousand shots, with 20 to 50 ns jitter at 16 kV charging voltage and more than 100 kA peak current amplitude. (orig.)

  12. Semi-Markov regime switching interest rate models and minimal entropy measure

    Science.gov (United States)

    Hunt, Julien; Devolder, Pierre

    2011-10-01

    In this paper, we present a discrete time regime switching binomial-like model of the term structure where the regime switches are governed by a discrete time semi-Markov process. We model the evolution of the prices of zero-coupon when given an initial term structure as in the model by Ho and Lee that we aim to extend. We discuss and derive conditions for the model to be arbitrage free and relate this to the notion of martingale measure. We explicitly show that due to the extra source of uncertainty coming from the underlying semi-Markov process, there are an infinite number of equivalent martingale measures. The notion of path independence is also studied in some detail, especially in the presence of regime switches. We deal with the market incompleteness by giving an explicit characterization of the minimal entropy martingale measure. We give an application to the pricing of a European bond option both in a Markov and semi-Markov framework. Finally, we draw some conclusions.

  13. The rate limiting process and its activation energy in the forming process of a Cu/Ta2O5/Pt gapless-type atomic switch

    Science.gov (United States)

    Shigeoka, Yuki; Tsuruoka, Tohru; Hasegawa, Tsuyoshi

    2018-03-01

    The rate limiting process in first resistive switching, called the “forming process”, is determined by measuring the switching time of an as-fabricated Cu/Ta2O5/Pt atomic switch as a function of the ambient temperature and the Ta2O5 thickness. The temperature dependence is well fitted by the Arrhenius equation, suggesting that a certain activation process dominates the switching phenomenon. The switching time increases linearly as the Ta2O5 thickness increases. The results herein clearly suggest that the rate limiting process is the drift of Cu cations in the Ta2O5 layer. We determine that the activation energy is 0.4 eV.

  14. Persistence, switch rates, drug consumption and costs of biological treatment of rheumatoid arthritis: an observational study in Italy.

    Science.gov (United States)

    Degli Esposti, Luca; Favalli, Ennio Giulio; Sangiorgi, Diego; Di Turi, Roberta; Farina, Giuseppina; Gambera, Marco; Ravasio, Roberto

    2017-01-01

    The aim of this analysis was to provide an estimate of drug utilization indicators (persistence, switch rate and drug consumption) on biologics and the corresponding costs (drugs, admissions and specialist care) incurred by the Italian National Health Service in the management of adult patients with rheumatoid arthritis (RA). We conducted an observational retrospective cohort analysis using the administrative databases of three local health units. We considered all patients aged ≥18 years with a diagnosis of RA and at least one biologic drug prescription between January 2010 and December 2012 (recruitment period). Persistence was defined as maintenance over the last 3 months of the follow-up period of the same biological therapy administered at the index date. A switch was defined as the presence of a biological therapy other than that administered at the index date during the last 3 months of the follow-up period. Hospital admissions (with a diagnosis of RA or other RA-related diagnoses), specialist outpatient services, instrumental diagnostics and pharmaceutical consumption were assessed. The drug utilization analysis took into account only biologics with at least 90 patients on treatment at baseline (adalimumab n=144, etanercept n=236 and infliximab n=94). In each year, etanercept showed better persistence with initial treatment than adalimumab or infliximab. Etanercept was characterized by the lowest number of patients increasing the initial drug consumption (2.6%) and by the highest number of patients reducing the initial drug consumption (10.5%). The mean cost of treatment for a patient persisting with the initial treatment was €12,388 (€14,182 for adalimumab, €12,103 for etanercept and €11,002 for infliximab). The treatment costs for patients switching from initial treatment during the first year of follow-up were higher than for patients who did not switch (€12,710 vs. €11,332). Persistence, switch rate and drug consumption seem to directly

  15. All-optical switching by domain wall motion in Co/Pd superlattices with a high-repetition-rate laser

    Science.gov (United States)

    Hoveyda, Farzaneh; Hohenstein, Erich; Smadici, Serban

    All-optical switching (AOS) of magnetization with femtosecond laser pulses has been demonstrated in ferri- and ferromagnetic materials. Current models mostly correlate ultrafast reversal with the uniform rotation of magnetization. In addition, while single-pulse switching in ferrimagnets has been reported, AOS in ferromagnetic Co/Pt has also been observed with overlapping pulses. This suggests the possibility to initiate a magnetization reversal with a high repetition rate laser. In our work, ferromagnetic Co/Pd superlattices, deposited by e-beam evaporation, were scanned under a high repetition rate Ti:Sapphire laser beam. Imaging with polarizing and magnetic force microscopes confirmed that AOS was attained. Intriguingly, measurements with a chopped beam showed a few ms delay before the reversed domains become visible. These domains gradually expanded by domain wall motion. We explain the delay with heat accumulation due to the high-repetition-rate laser pulses. The heat accumulation introduces in-plane thermal gradients, which apply forces on the magnetic domain walls. This suggests a model of the observed reversal by thermally driven domain wall motion.

  16. Persistence, switch rates, drug consumption and costs of biological treatment of rheumatoid arthritis: an observational study in Italy

    Directory of Open Access Journals (Sweden)

    Degli Esposti L

    2016-12-01

    Full Text Available Luca Degli Esposti,1 Ennio Giulio Favalli,2 Diego Sangiorgi,1 Roberta Di Turi,3 Giuseppina Farina,4 Marco Gambera,5 Roberto Ravasio,6 1CliCon S.r.l. – Health, Economics & Outcomes Research, Ravenna, 2Department of Rheumatology, Istituto Ortopedico Gaetano Pini, Milan, 3Local Pharmaceutical and Supplementary Assistance Unit, Roma Local Health Authority D, Rome, 4Internal Management Control Unit – Pharmaceutical Spending Control Sector, Caserta Local Health Authority, Caserta, 5Local Pharmaceutical Service, Bergamo Local Health Authority, Bergamo, 6Health Publishing & Services Srl, Milan, Italy Objectives: The aim of this analysis was to provide an estimate of drug utilization indicators (persistence, switch rate and drug consumption on biologics and the corresponding costs (drugs, admissions and specialist care incurred by the Italian National Health Service in the management of adult patients with rheumatoid arthritis (RA.Methods: We conducted an observational retrospective cohort analysis using the administrative databases of three local health units. We considered all patients aged ≥18 years with a diagnosis of RA and at least one biologic drug prescription between January 2010 and December 2012 (recruitment period. Persistence was defined as maintenance over the last 3 months of the follow-up period of the same biological therapy administered at the index date. A switch was defined as the presence of a biological therapy other than that administered at the index date during the last 3 months of the follow-up period. Hospital admissions (with a diagnosis of RA or other RA-related diagnoses, specialist outpatient services, instrumental diagnostics and pharmaceutical consumption were assessed.Results: The drug utilization analysis took into account only biologics with at least 90 patients on treatment at baseline (adalimumab n=144, etanercept n=236 and infliximab n=94. In each year, etanercept showed better persistence with initial

  17. Inventory control with two switch-over levels for a class of M/G/1 queueing systems with variable arrival and service rate

    NARCIS (Netherlands)

    Tijms, H.C.; van der Duyn Schouten, F.A.

    1978-01-01

    This paper deals with inventory control in a class of M/G/1 queueing systems. At each point of time the system can be switched from one of two possible stages to another. The rate of arrival process and the service rate depend on the stage of the system. The cost structure imposed on the model

  18. Temperature-independent fiber-Bragg-grating-based atmospheric pressure sensor

    Science.gov (United States)

    Zhang, Zhiguo; Shen, Chunyan; Li, Luming

    2018-03-01

    Atmospheric pressure is an important way to achieve a high degree of measurement for modern aircrafts, moreover, it is also an indispensable parameter in the meteorological telemetry system. With the development of society, people are increasingly concerned about the weather. Accurate and convenient atmospheric pressure parameters can provide strong support for meteorological analysis. However, electronic atmospheric pressure sensors currently in application suffer from several shortcomings. After an analysis and discussion, we propose an innovative structural design, in which a vacuum membrane box and a temperature-independent strain sensor based on an equal strength cantilever beam structure and fiber Bragg grating (FBG) sensors are used. We provide experimental verification of that the atmospheric pressure sensor device has the characteristics of a simple structure, lack of an external power supply, automatic temperature compensation, and high sensitivity. The sensor system has good sensitivity, which can be up to 100 nm/MPa, and repeatability. In addition, the device exhibits desired hysteresis.

  19. Temperature-independent strain sensing characteristics of coupled photonic crystal waveguides

    Science.gov (United States)

    Liu, Hai; Leng, Lemeng; Ma, Hanlin; Li, Lei; Zhang, Sheng; Cheng, Deqiang

    2016-05-01

    A highly sensitive strain sensor based on coupled two-dimensional (2D) photonic crystal waveguides consisting of dielectric rods array immersed in air is designed. The effective side-coupling between directional coupled waveguides and surrounding defect cavities gives flexibility in the choice of the sensing monitoring band. The coupling process and transmission spectral properties are analyzed by the finite difference time domain (FDTD) method. The influence of strain and temperature on the transmission spectrum is investigated by monitoring the wavelength shift in the loss peaks. The dual-channel sensing method is proposed to eliminate the cross sensitivity effect between the strain and ambient temperature, and render a new category of temperature-independent strain sensing devices.

  20. A Temperature-Independent Cold-Shock Protein Homolog Acts as a Virulence Factor in Xylella fastidiosa.

    Science.gov (United States)

    Burbank, Lindsey P; Stenger, Drake C

    2016-05-01

    Xylella fastidiosa, causal agent of Pierce's disease (PD) of grapevine, is a fastidious organism that requires very specific conditions for replication and plant colonization. Cold temperatures reduce growth and survival of X. fastidiosa both in vitro and in planta. However, little is known regarding physiological responses of X. fastidiosa to temperature changes. Cold-shock proteins (CSP), a family of nucleic acid-binding proteins, act as chaperones facilitating translation at low temperatures. Bacterial genomes often encode multiple CSP, some of which are strongly induced following exposure to cold. Additionally, CSP contribute to the general stress response through mRNA stabilization and posttranscriptional regulation. A putative CSP homolog (Csp1) with RNA-binding activity was identified in X. fastidiosa Stag's Leap. The csp1 gene lacked the long 5' untranslated region characteristic of cold-inducible genes and was expressed in a temperature-independent manner. As compared with the wild type, a deletion mutant of csp1 (∆csp1) had decreased survival rates following cold exposure and salt stress in vitro. The deletion mutant also was significantly less virulent in grapevine, as compared with the wild type, in the absence of cold stress. These results suggest an important function of X. fastidiosa Csp1 in response to cellular stress and during plant colonization.

  1. Effective interactions between nanoparticles: Creating temperature-independent solvation environments for self-assembly

    Science.gov (United States)

    Yadav, Hari O. S.; Shrivastav, Gourav; Agarwal, Manish; Chakravarty, Charusita

    2016-06-01

    The extent to which solvent-mediated effective interactions between nanoparticles can be predicted based on structure and associated thermodynamic estimators for bulk solvents and for solvation of single and pairs of nanoparticles is studied here. As a test of the approach, we analyse the strategy for creating temperature-independent solvent environments using a series of homologous chain fluids as solvents, as suggested by an experimental paper [M. I. Bodnarchuk et al., J. Am. Chem. Soc. 132, 11967 (2010)]. Our conclusions are based on molecular dynamics simulations of Au140(SC10H21)62 nanoparticles in n-alkane solvents, specifically hexane, octane, decane and dodecane, using the TraPPE-UA potential to model the alkanes and alkylthiols. The 140-atom gold core of the nanocrystal is held rigid in a truncated octahedral geometry and the gold-thiolate interaction is modeled using a Morse potential. The experimental observation was that the structural and rheological properties of n-alkane solvents are constant over a temperature range determined by equivalent solvent vapour pressures. We show that this is a consequence of the fact that long chain alkane liquids behave to a good approximation as simple liquids formed by packing of monomeric methyl/methylene units. Over the corresponding temperature range (233-361 K), the solvation environment is approximately constant at the single and pair nanoparticle levels under good solvent conditions. However, quantitative variations of the order of 10%-20% do exist in various quantities, such as molar volume of solute at infinite dilution, entropy of solvation, and onset distance for soft repulsions. In the opposite limit of a poor solvent, represented by vacuum in this study, the effective interactions between nanoparticles are no longer temperature-independent with attractive interactions increasing by up to 50% on decreasing the temperature from 361 K to 290 K, accompanied by an increase in emergent anisotropy due to

  2. Temperature-Independent Nuclear Quantum Effects on the Structure of Water

    Science.gov (United States)

    Kim, Kyung Hwan; Pathak, Harshad; Späh, Alexander; Perakis, Fivos; Mariedahl, Daniel; Sellberg, Jonas A.; Katayama, Tetsuo; Harada, Yoshihisa; Ogasawara, Hirohito; Pettersson, Lars G. M.; Nilsson, Anders

    2017-08-01

    Nuclear quantum effects (NQEs) have a significant influence on the hydrogen bonds in water and aqueous solutions and have thus been the topic of extensive studies. However, the microscopic origin and the corresponding temperature dependence of NQEs have been elusive and still remain the subject of ongoing discussion. Previous x-ray scattering investigations indicate that NQEs on the structure of water exhibit significant temperature dependence [Phys. Rev. Lett. 94, 047801 (2005), 10.1103/PhysRevLett.94.047801]. Here, by performing wide-angle x-ray scattering of H2O and D2O droplets at temperatures from 275 K down to 240 K, we determine the temperature dependence of NQEs on the structure of water down to the deeply supercooled regime. The data reveal that the magnitude of NQEs on the structure of water is temperature independent, as the structure factor of D2O is similar to H2O if the temperature is shifted by a constant 5 K, valid from ambient conditions to the deeply supercooled regime. Analysis of the accelerated growth of tetrahedral structures in supercooled H2O and D2O also shows similar behavior with a clear 5 K shift. The results indicate a constant compensation between NQEs delocalizing the proton in the librational motion away from the bond and in the OH stretch vibrational modes along the bond. This is consistent with the fact that only the vibrational ground state is populated at ambient and supercooled conditions.

  3. Switched reluctance motor drives

    Indian Academy of Sciences (India)

    Davis RM, Ray WF, Blake RJ 1981 Inverter drive for switched reluctance: circuits and component ratings. Inst. Elec. Eng. Proc. B128: 126-136. Ehsani M. 1991 Position Sensor elimination technique for the switched reluctance motor drive. US Patent No. 5,072,166. Ehsani M, Ramani K R 1993 Direct control strategies based ...

  4. IUD discontinuation rates, switching behavior, and user satisfaction: findings from a retrospective analysis of a mobile outreach service program in Pakistan.

    Science.gov (United States)

    Azmat, Syed Khurram; Hameed, Waqas; Mustafa, Ghulam; Hussain, Wajahat; Ahmed, Aftab; Bilgrami, Mohsina

    2013-01-01

    In Pakistan, the uptake rate for the intrauterine device (IUD) is very low at 2.5%. The most popular modern contraceptive methods in Pakistan are female sterilization and use of condoms. The Marie Stopes Society established its mobile outreach service delivery program with the aim of increasing use of modern quality contraceptive services, including the long-term reversible IUD, by women living in hard-to-reach areas. The present study attempts to assess IUD discontinuation rates and associated factors, including switching behavior and level of satisfaction with this type of service delivery. Using a cross-sectional approach, we contacted 681 women who had received an IUD from the Marie Stopes Society mobile outreach program during July and August 2009. Successful interviews were conducted with 639 of these women using a structured questionnaire. The data were analyzed with Stata 11.2 using simple descriptive Chi-square and Cox proportional techniques. Analysis revealed that 19.4% (95% confidence interval 16.3-22.5) of the women discontinued use of their IUD at 10 months and, of these women, the majority (69.4%) cited side effects as the main reason for discontinuation. Other factors, such as geographical catchment province, age of the woman, history of contraceptive use before IUD insertion, and side effects following insertion of the device, were found to be significantly associated with IUD. Amongst the women who had their IUD removed, 56.5% did not switch to any other contraceptive method, while 36.3% switched to either short-term or traditional methods, such as withdrawal, rhythm, and folk methods. Degree of satisfaction with the device was also significantly associated with discontinuation. Early discontinuation and not switching to another contraceptive method increases the risk of unplanned pregnancy. Health care workers should be trained in managing clients' concerns about the IUD to prevent discontinuation and providing counseling services for clients to

  5. Plasma erosion switch

    International Nuclear Information System (INIS)

    Mendel, C.W. Jr.; Goldstein, S.A.; Miller, P.A.

    1976-01-01

    The plasma erosion switch is a device capable of initially carrying high currents, and then of opening in nanoseconds to stand off high voltages. It depends upon the erosion of a plasma which initially fills the switch. The sheath between the plasma and the cathode behaves as a diode with a rapidly increasing A-K gap. Preliminary tests of the switch on the Proto I accelerator at Sandia will be described. In these tests, the switch consisted of a cylinder of highly ionized plasma four inches in diameter and one-inch thick surrounding a one-inch cathode. The switch shorted out prepulse voltages and allowed energy to be stored in the diode inductance outside the switch until the accelerator current reached 75 kA. The switch impedance then rose rapidly to approximately 100 ω in 5 nanoseconds, whereupon the accelerator current transferred to the cathode. Current rise rates of 3.10 13 A/sec were limited by cathode turn-on. Voltage rise rates of 10 15 V/sec were achieved. The elimination of prepulse and machine turn-on transients allowed A-K gaps of 2 mm to be used with 2.5 MV pulses, yielding average E fields of 12 MV/cm. Staged versions of the device are being built and should improve rise rates. The switch shows promise for use with future, higher power, lower inductance machines

  6. High rate of virological failure and low rate of switching to second-line treatment among adolescents and adults living with HIV on first-line ART in Myanmar, 2005-2015

    Science.gov (United States)

    Harries, Anthony D.; Kumar, Ajay M. V.; Oo, Myo Minn; Kyaw, Khine Wut Yee; Win, Than; Aung, Thet Ko; Min, Aung Chan; Oo, Htun Nyunt

    2017-01-01

    Background The number of people living with HIV on antiretroviral treatment (ART) in Myanmar has been increasing rapidly in recent years. This study aimed to estimate rates of virological failure on first-line ART and switching to second-line ART due to treatment failure at the Integrated HIV Care program (IHC). Methods Routinely collected data of all adolescent and adult patients living with HIV who were initiated on first-line ART at IHC between 2005 and 2015 were retrospectively analyzed. The cumulative hazard of virological failure on first-line ART and switching to second-line ART were estimated. Crude and adjusted hazard ratios were calculated using the Cox regression model to identify risk factors associated with the two outcomes. Results Of 23,248 adults and adolescents, 7,888 (34%) were tested for HIV viral load. The incidence rate of virological failure among those tested was 3.2 per 100 person-years follow-up and the rate of switching to second-line ART among all patients was 1.4 per 100 person-years follow-up. Factors associated with virological failure included: being adolescent; being lost to follow-up at least once; having WHO stage 3 and 4 at ART initiation; and having taken first-line ART elsewhere before coming to IHC. Of the 1032 patients who met virological failure criteria, 762 (74%) switched to second-line ART. Conclusions We found high rates of virological failure among one third of patients in the cohort who were tested for viral load. Of those failing virologically on first-line ART, about one quarter were not switched to second-line ART. Routine viral load monitoring, especially for those identified as having a higher risk of treatment failure, should be considered in this setting to detect all patients failing on first-line ART. Strategies also need to be put in place to prevent treatment failure and to treat more of those patients who are actually failing. PMID:28182786

  7. Is Switzerland an interest rate island after all? Time series and non-linear switching regime evidence

    OpenAIRE

    Feld, Lars P.; Köhler, Ekkehard A.

    2015-01-01

    Has the “Swiss interest rate anomaly” persisted after the financial crisis? Regarding the hypothesis that the Swiss interest rate anomaly results from systemic risk anticipation, we discuss whether Switzerland remains an interest rate island in the wake of the financial crisis. We find evidence for the demise of the interest rate bonus of the Swiss franc (CHF) vis-à-vis the Euro (EUR) after the Swiss National Bank (SNB) started to advocate an exchange rate floor with the Euro. After the compr...

  8. TEMPERATURE INDEPENDENT PHOTOLUMINESCENCE ...

    Indian Academy of Sciences (India)

    8

    Photoluminescence spectra of ZnO:Ce excited for near ultra violet region (325 nm) gives an ... Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy ..... stimulated emission from zinc oxide epilayers grown by plasma-assisted MBE, J.Cryst. Growth. 605 (1998) 184.

  9. TEMPERATURE INDEPENDENT PHOTOLUMINESCENCE ...

    Indian Academy of Sciences (India)

    8

    Microstructural characterization and topography of the synthesized samples were carried out by SEM ..... [17] Zalaj M., Gadolinium modified titanium dioxide materials for photoenergy applications: a review, J. Rare Earths. ... and Imaging of Textured Sprayed Er-Doped ZnO Films in the Near Ul- traviolet and Visible. Regions ...

  10. Magnetic switching

    International Nuclear Information System (INIS)

    Kirbie, H.C.

    1989-01-01

    Magnetic switching is a pulse compression technique that uses a saturable inductor (reactor) to pass pulses of energy between two capacitors. A high degree of pulse compression can be achieved in a network when several of these simple, magnetically switched circuits are connected in series. Individual inductors are designed to saturate in cascade as a pulse moves along the network. The technique is particularly useful when a single-pulse network must be very reliable or when a multi-pulse network must operate at a high pulse repetition frequency (PRF). Today, magnetic switches trigger spark gaps, sharpen the risetimes of high energy pulses, power large lasers, and drive high PRF linear induction accelerators. This paper will describe the technique of magnetic pulse compression using simple networks and design equations. A brief review of modern magnetic materials and of their role in magnetic switch design will be presented. 12 refs., 8 figs

  11. Effect of current compliance and voltage sweep rate on the resistive switching of HfO2/ITO/Invar structure as measured by conductive atomic force microscopy

    Science.gov (United States)

    Wu, You-Lin; Liao, Chun-Wei; Ling, Jing-Jenn

    2014-06-01

    The electrical characterization of HfO2/ITO/Invar resistive switching memory structure was studied using conductive atomic force microscopy (AFM) with a semiconductor parameter analyzer, Agilent 4156C. The metal alloy Invar was used as the metal substrate to ensure good ohmic contact with the substrate holder of the AFM. A conductive Pt/Ir AFM tip was placed in direct contact with the HfO2 surface, such that it acted as the top electrode. Nanoscale current-voltage (I-V) characteristics of the HfO2/ITO/Invar structure were measured by applying a ramp voltage through the conductive AFM tip at various current compliances and ramp voltage sweep rates. It was found that the resistance of the low resistance state (RLRS) decreased with increasing current compliance value, but resistance of high resistance state (RHRS) barely changed. However, both the RHRS and RLRS decreased as the voltage sweep rate increased. The reasons for this dependency on current compliance and voltage sweep rate are discussed.

  12. A gain-coefficient switched Alexandrite laser

    International Nuclear Information System (INIS)

    Lee, Chris J; Van der Slot, Peter J M; Boller, Klaus-J

    2013-01-01

    We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ at a repetition rate of 5 Hz.

  13. A CW Gunn diode bistable switching element.

    Science.gov (United States)

    Hurtado, M.; Rosenbaum, F. J.

    1972-01-01

    Experiments with a current-controlled bistable switching element using a CW Gunn diode are reported. Switching rates of the order of 10 MHz have been obtained. Switching is initiated by current pulses of short duration (5-10 ns). Rise times of the order of several nanoseconds could be obtained.

  14. 47 CFR 69.106 - Local switching.

    Science.gov (United States)

    2010-10-01

    ... foreign services that use local exchange switching facilities. (c) If end users of an interstate or... local exchange carriers shall establish rate elements for local switching as follows: (1) Price cap... use local exchange switching facilities for the provision of interstate or foreign services. The...

  15. High-Sequence Diversity and Rapid Virus Turnover Contribute to Higher Rates of Coreceptor Switching in Treatment-Experienced Subjects with HIV-1 Viremia.

    Science.gov (United States)

    Nedellec, Rebecca; Herbeck, Joshua T; Hunt, Peter W; Deeks, Steven G; Mullins, James I; Anton, Elizabeth D; Reeves, Jacqueline D; Mosier, Donald E

    2017-03-01

    Coreceptor switching from CCR5 to CXCR4 is common during chronic HIV-1 infection, but is even more common in individuals who have failed antiretroviral therapy (ART). Prior studies have suggested rapid mutation and/or recombination of HIV-1 envelope (env) genes during coreceptor switching. We compared the functional and genotypic changes in env of viruses from viremic subjects who had failed ART just before and after coreceptor switching and compared those to viruses from matched subjects without coreceptor switching. Analysis of multiple unique functional env clones from each subject revealed extensive diversity at both sample time points and rapid diversification of sequences during the 4-month interval in viruses from both 9 subjects with coreceptor switching and 15 control subjects. Only two subjects had envs with evidence of recombination. Three findings distinguished env clones from subjects with coreceptor switching from controls: (1) lower entry efficiency via CCR5; (2) longer V1/V2 regions; and (3), lower nadir CD4 T cell counts during prior years of infection. Most of these subjects harbored virus with lower replicative capacity associated with protease (PR) and/or reverse transcriptase inhibitor resistance mutations, and the extensive diversification tended to lead either to improved entry efficiency via CCR5 or the gain of entry function via CXCR4. These results suggest that R5X4 or X4 variants emerge from a diverse, low-fitness landscape shaped by chronic infection, multiple ART resistance mutations, the availability of target cells, and reduced entry efficiency via CCR5.

  16. Photonic MEMS switch applications

    Science.gov (United States)

    Husain, Anis

    2001-07-01

    As carriers and service providers continue their quest for profitable network solutions, they have shifted their focus from raw bandwidth to rapid provisioning, delivery and management of revenue generating services. Inherently transparent to data rate the transmission wavelength and data format, MEMS add scalability, reliability, low power and compact size providing flexible solutions to the management and/or fiber channels in long haul, metro, and access networks. MEMS based photonic switches have gone from the lab to commercial availability and are now currently in carrier trials and volume production. 2D MEMS switches offer low up-front deployment costs while remaining scalable to large arrays. They allow for transparent, native protocol transmission. 2D switches enable rapid service turn-up and management for many existing and emerging revenue rich services such as storage connectivity, optical Ethernet, wavelength leasing and optical VPN. As the network services evolve, the larger 3D MEMS switches, which provide greater scalability and flexibility, will become economically viable to serve the ever-increasing needs.

  17. Switched on!

    CERN Multimedia

    2008-01-01

    Like a star arriving on stage, impatiently followed by each member of CERN personnel and by millions of eyes around the world, the first beam of protons has circulated in the LHC. After years in the making and months of increasing anticipation, today the work of hundreds of people has borne fruit. WELL DONE to all! Successfully steered around the 27 kilometres of the world’s most powerful particle accelerator at 10:28 this morning, this first beam of protons circulating in the ring marks a key moment in the transition from over two decades of preparation to a new era of scientific discovery. "It’s a fantastic moment," said the LHC project leader Lyn Evans, "we can now look forward to a new era of understanding about the origins and evolution of the universe". Starting up a major new particle accelerator takes much more than flipping a switch. Thousands of individual elements have to work in harmony, timings have to be synchronize...

  18. A 5 V-to-3.3 V CMOS Linear Regulator with Three-Output Temperature-Independent Reference Voltages

    Directory of Open Access Journals (Sweden)

    San-Fu Wang

    2016-01-01

    Full Text Available This paper presents a 5 V-to-3.3 V linear regulator circuit, which uses 3.3 V CMOS transistors to replace the 5 V CMOS transistors. Thus, the complexity of the manufacturing semiconductor process can be improved. The proposed linear regulator is implemented by cascode architecture, which requires three different reference voltages as the bias voltages of its circuit. Thus, the three-output temperature-independent reference voltage circuit is proposed, which provides three accurate reference voltages simultaneously. The three-output temperature-independent reference voltages also can be used in other circuits of the chip. By using the proposed temperature-independent reference voltages, the proposed linear regulator can provide an accurate output voltage, and it is suitable for low cost, small size, and highly integrated system-on-chip (SoC applications. Moreover, the proposed linear regulator uses the cascode technique, which improves both the gain performance and the isolation performance. Therefore, the proposed linear regulator has a good performance in reference voltage to output voltage isolation. The voltage variation of the linear regulator is less than 2.153% in the temperature range of −40°C–120°C, and the power supply rejection ratio (PSRR is less than −42.8 dB at 60 Hz. The regulator can support 0~200 mA output current. The core area is less than 0.16 mm2.

  19. High level of viral suppression and low switch rate to second-line antiretroviral therapy among HIV-infected adult patients followed over five years: retrospective analysis of the DART trial.

    Directory of Open Access Journals (Sweden)

    Cissy Kityo

    Full Text Available In contrast to resource-rich countries, most HIV-infected patients in resource-limited countries receive treatment without virological monitoring. There are few long-term data, in this setting, on rates of viral suppression or switch to second-line antiretroviral therapy. The DART trial compared clinically driven monitoring (CDM versus routine laboratory (CD4/haematology/biochemistry and clinical monitoring (LCM in HIV-infected adults initiating therapy. There was no virological monitoring in either study group during follow-up, but viral load was measured in Ugandan participants at trial closure. Two thousand three hundred and seventeen (2317 participants from this country initiated antiretroviral therapy with zidovudine/lamivudine plus tenofovir (n = 1717, abacavir (n = 300, or nevirapine (n = 300. Of 1896 (81.8% participants who were alive and in follow-up at trial closure (median 5.1 years after therapy initiation, 1507 (79.5% were on first-line and 389 (20.5% on second-line antiretroviral therapy. The overall switch rate after the first year was 5.6 per 100 person-years; the rate was substantially higher in participants with low baseline CD4 counts (<50 cells/mm3. Among 1207 (80.1% first-line participants with viral load measured, HIV RNA was <400 copies/ml in 963 (79.8%, 400-999 copies/ml in 37 (3.1%, 1,000-9,999 copies/ml in 110 (9.1%, and ≥10,000 copies/ml in 97 (8.0%. The proportion with HIV RNA <400 copies/ml was slightly lower (difference 7.1%, 95% CI 2.5 to 11.5% in CDM (76.3% than in LCM (83.4%. Among 252 (64.8% second-line participants with viral load measured (median 2.3 years after switch, HIV RNA was <400 copies/ml in 226 (89.7%, with no difference between monitoring strategies. Low switch rates and high, sustained levels of viral suppression are achievable without viral load or CD4 count monitoring in the context of high-quality clinical care.ISRCTN13968779.

  20. Rating

    OpenAIRE

    Karas, Vladimír

    2006-01-01

    Charakteristika ratingu. Dělení a druhy ratingu (rating emise × rating emitenta; dlouhodobý rating × krátkodobý rating; mezinárodní rating × lokální rating). Obecné požadavky kladené na rating. Proces tvorby ratingu. Vyžádaný rating. Nevyžádaný rating. Ratingový proces na bázi volně přístupných informací. Uplatňované ratingové systémy. Ratingová kriteria. Využití a interpretace ratingové známky. Funkce ratingu. Rating v souvislosti s BASEL II. Rating v souvislosti s hospodářskými krizemi....

  1. The dynamic nature of systems consolidation: Stress during learning as a switch guiding the rate of the hippocampal dependency and memory quality.

    Science.gov (United States)

    Pedraza, Lizeth K; Sierra, Rodrigo O; Boos, Flávia Z; Haubrich, Josué; Quillfeldt, Jorge A; Alvares, Lucas de Oliveira

    2016-03-01

    Memory fades over time, becoming more schematic or abstract. The loss of contextual detail in memory may reflect a time-dependent change in the brain structures supporting memory. It has been well established that contextual fear memory relies on the hippocampus for expression shortly after learning, but it becomes hippocampus-independent at a later time point, a process called systems consolidation. This time-dependent process correlates with the loss of memory precision. Here, we investigated whether training intensity predicts the gradual decay of hippocampal dependency to retrieve memory, and the quality of the contextual memory representation over time. We have found that training intensity modulates the progressive decay of hippocampal dependency and memory precision. Strong training intensity accelerates systems consolidation and memory generalization in a remarkable timeframe match. The mechanisms underpinning such process are triggered by glucocorticoid and noradrenaline released during training. These results suggest that the stress levels during emotional learning act as a switch, determining the fate of memory quality. Moderate stress will create a detailed memory, whereas a highly stressful training will develop a generic gist-like memory. © 2015 Wiley Periodicals, Inc.

  2. Controller Architectures for Switching

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2009-01-01

    This paper investigate different controller architectures in connection with controller switching. The controller switching is derived by using the Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization. A number of different architectures for the implementation of the YJBK parameterization...... are described and applied in connection with controller switching. An architecture that does not include inversion of the coprime factors is introduced. This architecture will make controller switching particular simple....

  3. Photoresistance switching of plasmonic nanopores.

    Science.gov (United States)

    Li, Yi; Nicoli, Francesca; Chen, Chang; Lagae, Liesbet; Groeseneken, Guido; Stakenborg, Tim; Zandbergen, Henny W; Dekker, Cees; Van Dorpe, Pol; Jonsson, Magnus P

    2015-01-14

    Fast and reversible modulation of ion flow through nanosized apertures is important for many nanofluidic applications, including sensing and separation systems. Here, we present the first demonstration of a reversible plasmon-controlled nanofluidic valve. We show that plasmonic nanopores (solid-state nanopores integrated with metal nanocavities) can be used as a fluidic switch upon optical excitation. We systematically investigate the effects of laser illumination of single plasmonic nanopores and experimentally demonstrate photoresistance switching where fluidic transport and ion flow are switched on or off. This is manifested as a large (∼ 1-2 orders of magnitude) increase in the ionic nanopore resistance and an accompanying current rectification upon illumination at high laser powers (tens of milliwatts). At lower laser powers, the resistance decreases monotonically with increasing power, followed by an abrupt transition to high resistances at a certain threshold power. A similar rapid transition, although at a lower threshold power, is observed when the power is instead swept from high to low power. This hysteretic behavior is found to be dependent on the rate of the power sweep. The photoresistance switching effect is attributed to plasmon-induced formation and growth of nanobubbles that reversibly block the ionic current through the nanopore from one side of the membrane. This explanation is corroborated by finite-element simulations of a nanobubble in the nanopore that show the switching and the rectification.

  4. Fluctuation-induced switching and the switching path distribution.

    Science.gov (United States)

    Dykman, Mark

    2009-03-01

    Fluctuation-induced switching is at the root of diverse phenomena currently studied in Josephson junctions, nano-mechanical systems, nano-magnets, and optically trapped atoms. In a fluctuation leading to switching the system must overcome an effective barrier, making switching events rare, for low fluctuation intensity. We will provide an overview of the methods of finding the switching barrier for systems away from thermal equilibrium. Generic features of the barrier, such as scaling with the system parameters, will be discussed. We will also discuss the motion of the system in switching and the ways of controlling it. Two major classes of systems will be considered: dynamical systems, where fluctuations are induced by noise, and birth-death systems. Even though the motion during switching is random, the paths followed in switching form a narrow tube in phase space of the system centered at the most probable path. The paths distribution is generally Gaussian and has specific features, which have been seen in the experiment [1]. Finding the most probable path itself can be reduced to solving a problem of Hamiltonian dynamics of an auxiliary noise-free system. The solution also gives the switching barrier. The barrier can be found explicitly close to parameter values where the number of stable states of the system changes and the dynamics is controlled by a slow variable. The scaling of the barrier height depends on the type of the corresponding bifurcation. We show that, both for birth-death and for Gaussian noise driven systems, the presence of even weak non-Gaussian noise can strongly modify the switching rate. The effect is described in a simple explicit form [2,3]. Weak deviations of the noise statistics from Gaussian can be sensitively detected using balanced dynamical bridge, where this deviation makes the populations of coexisting stable states different from each other; a realization of such a bridge will be discussed. We will also discuss the sharp

  5. A new Zero-Current-Transition PWM switching cell

    Energy Technology Data Exchange (ETDEWEB)

    Grigore, V. [Electronics and Telecommunications Faculty, `Politechnica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics

    1997-12-31

    In this paper a new Zero-Current-Transition (ZCT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus as auxiliary circuit. The auxiliary circuit is inactive during the ON ad OFF intervals of the switches in the normal PWM switch. The transitions between the two states are controlled by the auxiliary circuit. Prior to turn-off, the current through the active switch in the PWM cell is forced to zero, thus the turn-off losses of the active switch are practically eliminated. At turn-on the auxiliary circuit slows down the growing rate of the current through the main switch. Thus, turn-on losses are also very much reduced. The active switch operates under ZCT conditions, the passive switch (diode) has a controlled reverse recovery, while the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 3 refs.

  6. Multiuser switched diversity scheduling schemes

    KAUST Repository

    Shaqfeh, Mohammad

    2012-09-01

    Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed, and ordered scheduling mechanism. The main idea behind these schemes is that slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we characterize the achievable rate region of multiuser switched diversity systems and compare it with the rate region of full feedback multiuser diversity systems. We propose also a novel proportional fair multiuser switched-based scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the feedback thresholds. We finally demonstrate by numerical examples that switched-diversity scheduling schemes operate within 0.3 bits/sec/Hz from the ultimate network capacity of full feedback systems in Rayleigh fading conditions. © 2012 IEEE.

  7. Phenotypic switching in bacteria

    Science.gov (United States)

    Merrin, Jack

    Living matter is a non-equilibrium system in which many components work in parallel to perpetuate themselves through a fluctuating environment. Physiological states or functionalities revealed by a particular environment are called phenotypes. Transitions between phenotypes may occur either spontaneously or via interaction with the environment. Even in the same environment, genetically identical bacteria can exhibit different phenotypes of a continuous or discrete nature. In this thesis, we pursued three lines of investigation into discrete phenotypic heterogeneity in bacterial populations: the quantitative characterization of the so-called bacterial persistence, a theoretical model of phenotypic switching based on those measurements, and the design of artificial genetic networks which implement this model. Persistence is the phenotype of a subpopulation of bacteria with a reduced sensitivity to antibiotics. We developed a microfluidic apparatus, which allowed us to monitor the growth rates of individual cells while applying repeated cycles of antibiotic treatments. We were able to identify distinct phenotypes (normal and persistent) and characterize the stochastic transitions between them. We also found that phenotypic heterogeneity was present prior to any environmental cue such as antibiotic exposure. Motivated by the experiments with persisters, we formulated a theoretical model describing the dynamic behavior of several discrete phenotypes in a periodically varying environment. This theoretical framework allowed us to quantitatively predict the fitness of dynamic populations and to compare survival strategies according to environmental time-symmetries. These calculations suggested that persistence is a strategy used by bacterial populations to adapt to fluctuating environments. Knowledge of the phenotypic transition rates for persistence may provide statistical information about the typical environments of bacteria. We also describe a design of artificial

  8. Saturated Switching Systems

    CERN Document Server

    Benzaouia, Abdellah

    2012-01-01

    Saturated Switching Systems treats the problem of actuator saturation, inherent in all dynamical systems by using two approaches: positive invariance in which the controller is designed to work within a region of non-saturating linear behaviour; and saturation technique which allows saturation but guarantees asymptotic stability. The results obtained are extended from the linear systems in which they were first developed to switching systems with uncertainties, 2D switching systems, switching systems with Markovian jumping and switching systems of the Takagi-Sugeno type. The text represents a thoroughly referenced distillation of results obtained in this field during the last decade. The selected tool for analysis and design of stabilizing controllers is based on multiple Lyapunov functions and linear matrix inequalities. All the results are illustrated with numerical examples and figures many of them being modelled using MATLAB®. Saturated Switching Systems will be of interest to academic researchers in con...

  9. A solid-state dielectric elastomer switch for soft logic

    Energy Technology Data Exchange (ETDEWEB)

    Chau, Nixon [Biomimetics Laboratory, Auckland Bioengineering Institute, The University of Auckland, Level 6, 70 Symonds Street, Auckland 1010 (New Zealand); Slipher, Geoffrey A., E-mail: geoffrey.a.slipher.civ@mail.mil; Mrozek, Randy A. [U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783 (United States); O' Brien, Benjamin M. [StretchSense, Ltd., 27 Walls Rd., Penrose, Auckland 1061 (New Zealand); Anderson, Iain A. [Biomimetics Laboratory, Auckland Bioengineering Institute, The University of Auckland, Level 6, 70 Symonds Street, Auckland 1010 (New Zealand); StretchSense, Ltd., 27 Walls Rd., Penrose, Auckland 1061 (New Zealand); Department of Engineering Science, School of Engineering, The University of Auckland, Level 3, 70 Symonds Street, Auckland 1010 (New Zealand)

    2016-03-07

    In this paper, we describe a stretchable solid-state electronic switching material that operates at high voltage potentials, as well as a switch material benchmarking technique that utilizes a modular dielectric elastomer (artificial muscle) ring oscillator. The solid-state switching material was integrated into our oscillator, which self-started after 16 s and performed 5 oscillations at a frequency of 1.05 Hz with 3.25 kV DC input. Our materials-by-design approach for the nickel filled polydimethylsiloxane based switch has resulted in significant improvements over previous carbon grease-based switches in four key areas, namely, sharpness of switching behavior upon applied stretch, magnitude of electrical resistance change, ease of manufacture, and production rate. Switch lifetime was demonstrated to be in the range of tens to hundreds of cycles with the current process. An interesting and potentially useful strain-based switching hysteresis behavior is also presented.

  10. Effective switching frequency multiplier inverter

    Science.gov (United States)

    Su, Gui-Jia; Peng, Fang Z.

    2007-08-07

    A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

  11. FreeSWITCH Cookbook

    CERN Document Server

    Minessale, Anthony

    2012-01-01

    This is a problem-solution approach to take your FreeSWITCH skills to the next level, where everything is explained in a practical way. If you are a system administrator, hobbyist, or someone who uses FreeSWITCH on a regular basis, this book is for you. Whether you are a FreeSWITCH expert or just getting started, this book will take your skills to the next level.

  12. Incorrect predictions reduce switch costs.

    Science.gov (United States)

    Kleinsorge, Thomas; Scheil, Juliane

    2015-07-01

    In three experiments, we combined two sources of conflict within a modified task-switching procedure. The first source of conflict was the one inherent in any task switching situation, namely the conflict between a task set activated by the recent performance of another task and the task set needed to perform the actually relevant task. The second source of conflict was induced by requiring participants to guess aspects of the upcoming task (Exps. 1 & 2: task identity; Exp. 3: position of task precue). In case of an incorrect guess, a conflict accrues between the representation of the guessed task and the actually relevant task. In Experiments 1 and 2, incorrect guesses led to an overall increase of reaction times and error rates, but they reduced task switch costs compared to conditions in which participants predicted the correct task. In Experiment 3, incorrect guesses resulted in faster performance overall and to a selective decrease of reaction times in task switch trials when the cue-target interval was long. We interpret these findings in terms of an enhanced level of controlled processing induced by a combination of two sources of conflict converging upon the same target of cognitive control. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Switching strategies to optimize search

    Science.gov (United States)

    Shlesinger, Michael F.

    2016-03-01

    Search strategies are explored when the search time is fixed, success is probabilistic and the estimate for success can diminish with time if there is not a successful result. Under the time constraint the problem is to find the optimal time to switch a search strategy or search location. Several variables are taken into account, including cost, gain, rate of success if a target is present and the probability that a target is present.

  14. Trading off switch costs and stimulus availability benefits: An investigation of voluntary task-switching behavior in a predictable dynamic multitasking environment.

    Science.gov (United States)

    Mittelstädt, Victor; Miller, Jeff; Kiesel, Andrea

    2018-03-09

    In the present study, we introduce a novel, self-organized task-switching paradigm that can be used to study more directly the determinants of switching. Instead of instructing participants to randomly switch between tasks, as in the classic voluntary task-switching paradigm (Arrington & Logan, 2004), we instructed participants to optimize their task performance in a voluntary task-switching environment in which the stimulus associated with the previously selected task appeared in each trial after a delay. Importantly, the stimulus onset asynchrony (SOA) increased further with each additional repetition of this task, whereas the stimulus needed for a task switch was always immediately available. We conducted two experiments with different SOA increments (i.e., Exp. 1a = 50 ms, Exp. 1b = 33 ms) to see whether this procedure would induce switching behavior, and we explored how people trade off switch costs against the increasing availability of the stimulus needed for a task repetition. We observed that participants adapted their behavior to the different task environments (i.e., SOA increments) and that participants switched tasks when the SOA in task switches approximately matched the switch costs. Moreover, correlational analyses indicated relations between individual switch costs and individual switch rates across participants. Together, these results demonstrate that participants were sensitive to the increased availability of switch stimuli in deciding whether to switch or to repeat, which in turn demonstrates flexible adaptive task selection behavior. We suggest that performance limitations in task switching interact with the task environment to influence switching behavior.

  15. Switch on, switch off: stiction in nanoelectromechanical switches

    KAUST Repository

    Wagner, Till J W

    2013-06-13

    We present a theoretical investigation of stiction in nanoscale electromechanical contact switches. We develop a mathematical model to describe the deflection of a cantilever beam in response to both electrostatic and van der Waals forces. Particular focus is given to the question of whether adhesive van der Waals forces cause the cantilever to remain in the \\'ON\\' state even when the electrostatic forces are removed. In contrast to previous studies, our theory accounts for deflections with large slopes (i.e. geometrically nonlinear). We solve the resulting equations numerically to study how a cantilever beam adheres to a rigid electrode: transitions between \\'free\\', \\'pinned\\' and \\'clamped\\' states are shown to be discontinuous and to exhibit significant hysteresis. Our findings are compared to previous results from linearized models and the implications for nanoelectromechanical cantilever switch design are discussed. © 2013 IOP Publishing Ltd.

  16. Wide Bandgap Extrinsic Photoconductive Switches

    Science.gov (United States)

    Sullivan, James Stephen

    Wide Bandgap Extrinsic Photoconductive Switches Semi-insulating Gallium Nitride, 4H and 6H Silicon Carbide are attractive materials for compact, high voltage, extrinsic, photoconductive switches due to their wide bandgap, high dark resistance, high critical electric field strength and high electron saturation velocity. These wide bandgap semiconductors are made semi-insulating by the addition of vanadium (4H and 6H-SiC) and iron (2H-GaN) impurities that form deep acceptors. These deep acceptors trap electrons donated from shallow donor impurities. The electrons can be optically excited from these deep acceptor levels into the conduction band to transition the wide bandgap semiconductor materials from a semi-insulating to a conducting state. Extrinsic photoconductive switches with opposing electrodes have been constructed using vanadium compensated 6H-SiC and iron compensated 2H-GaN. These extrinsic photoconductive switches were tested at high voltage and high power to determine if they could be successfully used as the closing switch in compact medical accelerators. The successful development of a vanadium compensated, 6H-SiC extrinsic photoconductive switch for use as a closing switch for compact accelerator applications was realized by improvements made to the vanadium, nitrogen and boron impurity densities. The changes made to the impurity densities were based on the physical intuition outlined and simple rate equation models. The final 6H-SiC impurity 'recipe' calls for vanadium, nitrogen and boron densities of 2.5 e17 cm-3, 1.25e17 cm-3 and ≤ 1e16 cm-3, respectively. This recipe was originally developed to maximize the quantum efficiency of the vanadium compensated 6H-SiC, while maintaining a thermally stable semi-insulating material. The rate equation models indicate that, besides increasing the quantum efficiency, the impurity recipe should be expected to also increase the carrier recombination time. Three generations of 6H-SiC materials were tested. The

  17. Switched diversity approach for multireceiving optical wireless systems.

    Science.gov (United States)

    Moradi, Hassan; Refai, Hazem H; Lopresti, Peter G

    2011-10-10

    A number of existing spatial diversity schemes have been shown to improve the performance of optical wireless communication systems in diversity-rich environments. Among all, switched diversity has low complexity and is simple to implement. In this paper, an innovative spatial diversity scheme based on switched diversity is proposed. The scheme, namely switch-to-dominant combining, contributes to a higher bit error rate (BER) performance when compared to conventional switched diversity schemes, including switch-and-stay and switch-and-examine diversity. The optical multireceiver wireless system operates in a spatially correlated and lognormally distributed fading channel. Analytical analyses are conducted to demonstrate BER and processing load performance offered by the new scheme and compare them to available schemes, i.e., conventional switched combining and selection combining. © 2011 Optical Society of America

  18. Switch mode power supply

    International Nuclear Information System (INIS)

    Kim, Hui Jun

    1993-06-01

    This book concentrates on switch mode power supply. It has four parts, which are introduction of switch mode power supply with DC-DC converter such as Buck converter boost converter, Buck-boost converter and PWM control circuit, explanation for SMPS with DC-DC converter modeling and power mode control, resonance converter like resonance switch, converter, multi resonance converter and series resonance and parallel resonance converters, basic test of SMPS with PWM control circuit, Buck converter, Boost converter, flyback converter, forward converter and IC for control circuit.

  19. BROOKHAVEN: Switched power

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    Hosted by Brookhaven's Center for Accelerator Physics, a recent workshop on switched power techniques attracted a group of specialists to Shelter Island, New York, location of several important physics meetings, including the famous 1947 sessions which helped mould modern quantum electrodynamics. The current interest in switched power stemmed from a series of papers by W. Willis of CERN, starting in 1984. The idea is for stored electrical energy to be suddenly switched on to a transmission line, producing a very short (about 10 ps) electromagnetic pulse in a region traversed by a particle beam

  20. Electromechanical magnetization switching

    Energy Technology Data Exchange (ETDEWEB)

    Chudnovsky, Eugene M. [Department of Physics and Astronomy, Lehman College and Graduate School, The City University of New York, 250 Bedford Park Boulevard West, Bronx, New York 10468-1589 (United States); Jaafar, Reem [Department of Mathematics, Engineering and Computer Science, LaGuardia Community College, The City University of New York, 31-10 Thomson Avenue, Long Island City, New York 11101 (United States)

    2015-03-14

    We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained.

  1. Electromechanical magnetization switching

    International Nuclear Information System (INIS)

    Chudnovsky, Eugene M.; Jaafar, Reem

    2015-01-01

    We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained

  2. JUNOS Enterprise Switching

    CERN Document Server

    Reynolds, Harry

    2009-01-01

    JUNOS Enterprise Switching is the only detailed technical book on Juniper Networks' new Ethernet-switching EX product platform. With this book, you'll learn all about the hardware and ASIC design prowess of the EX platform, as well as the JUNOS Software that powers it. Not only is this extremely practical book a useful, hands-on manual to the EX platform, it also makes an excellent study guide for certification exams in the JNTCP enterprise tracks. The authors have based JUNOS Enterprise Switching on their own Juniper training practices and programs, as well as the configuration, maintenanc

  3. Topological photonic orbital-angular-momentum switch

    Science.gov (United States)

    Luo, Xi-Wang; Zhang, Chuanwei; Guo, Guang-Can; Zhou, Zheng-Wei

    2018-04-01

    The large number of available orbital-angular-momentum (OAM) states of photons provides a unique resource for many important applications in quantum information and optical communications. However, conventional OAM switching devices usually rely on precise parameter control and are limited by slow switching rate and low efficiency. Here we propose a robust, fast, and efficient photonic OAM switch device based on a topological process, where photons are adiabatically pumped to a target OAM state on demand. Such topological OAM pumping can be realized through manipulating photons in a few degenerate main cavities and involves only a limited number of optical elements. A large change of OAM at ˜10q can be realized with only q degenerate main cavities and at most 5 q pumping cycles. The topological photonic OAM switch may become a powerful device for broad applications in many different fields and motivate a topological design of conventional optical devices.

  4. Modeling switching behaviour of direct selling customers

    Directory of Open Access Journals (Sweden)

    P Msweli-Mbanga

    2004-04-01

    Full Text Available The direct selling industry suffers a high turnover rate of salespeople, resulting in high costs of training new salespeople. Further costs are incurred when broken relationships with customers cause them to switch from one product supplier to another. This study identifies twelve factors that drive the switching behaviour of direct sales customers and examines the extent to which these factors influence switching. Exploratory factor analysis was used to assess the validity of these factors. The factors were represented in a model that posits that an interpersonal relationship between a direct sales person and a customer moderates the relationship between switching behaviour and loyalty. Structural equation modeling was used to test the proposed model. The author then discusses the empirical findings and their managerial implications, providing further avenues for research.

  5. uv preilluminated gas switches

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, L.P.; Orham, E.L.; Stowers, I.F.; Braucht, J.R.

    1980-06-03

    We have designed, built, and characterized uv preilluminated gas switches for a trigger circuit and a low inductance discharge circuit. These switches have been incorporated into a 54 x 76 x 150 cm pulser module to produce a 1 Ma output current rising at 5 x 10/sup 12/ amps/sec with 1 ns jitter. Twenty such modules will be used on the Nova Inertial Confinement Fusion Laser System for plasma retropulse shutters.

  6. Switching power supply filter

    Science.gov (United States)

    Kumar, Prithvi R. (Inventor); Abare, Wayne (Inventor)

    1989-01-01

    A filter for a switching power supply. The filter includes a common mode inductor with coil configurations allowing differential mode current from a dc source to pass through but attenuating common mode noise from the power supply so that the noise does not reach the dc source. The invention also includes the use of feed through capacitors at the switching power supply input terminals to provide further high-frequency noise attenuation.

  7. uv preilluminated gas switches

    International Nuclear Information System (INIS)

    Bradley, L.P.; Orham, E.L.; Stowers, I.F.; Braucht, J.R.

    1980-01-01

    We have designed, built, and characterized uv preilluminated gas switches for a trigger circuit and a low inductance discharge circuit. These switches have been incorporated into a 54 x 76 x 150 cm pulser module to produce a 1 Ma output current rising at 5 x 10 12 amps/sec with 1 ns jitter. Twenty such modules will be used on the Nova Inertial Confinement Fusion Laser System for plasma retropulse shutters

  8. Photonics in switching

    CERN Document Server

    Midwinter, John E; Kelley, Paul

    1993-01-01

    Photonics in Switching provides a broad, balanced overview of the use of optics or photonics in switching, from materials and devices to system architecture. The chapters, each written by an expert in the field, survey the key technologies, setting them in context and highlighting their benefits and possible applications. This book is a valuable resource for those working in the communications industry, either at the professional or student level, who do not have extensive background knowledge or the underlying physics of the technology.

  9. Optical switching systems using nanostructures

    DEFF Research Database (Denmark)

    Stubkjær, Kristian

    2004-01-01

    High capacity multiservice optical networks require compact and efficient switches. The potential benefits of optical switch elements based on nanostructured material are reviewed considering various material systems.......High capacity multiservice optical networks require compact and efficient switches. The potential benefits of optical switch elements based on nanostructured material are reviewed considering various material systems....

  10. Understanding and Supporting Window Switching

    NARCIS (Netherlands)

    Tak, S.

    2011-01-01

    Switching between windows on a computer is a frequent activity, but finding and switching to the target window can be inefficient. This thesis aims to better un-derstand and support window switching. It explores two issues: (1) the lack of knowledge of how people currently interact with and switch

  11. Low inductance gas switching.

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, Ray; Harjes, Henry Charles III; Wallace, Zachariah; Elizondo, Juan E.

    2007-10-01

    The laser trigger switch (LTS) is a key component in ZR-type pulsed power systems. In ZR, the pulse rise time through the LTS is > 200 ns and additional stages of pulse compression are required to achieve the desired <100 ns rise time. The inductance of the LTS ({approx}500nH) in large part determines the energy transfer time through the switch and there is much to be gained in improving system performance and reducing system costs by reducing this inductance. The current path through the cascade section of the ZR LTS is at a diameter of {approx} 6-inches which is certainly not optimal from an inductance point of view. The LTS connects components of much greater diameter (typically 4-5 feet). In this LDRD the viability of switch concepts in which the diameter of cascade section is greatly increased have been investigated. The key technical question to be answered was, will the desired multi-channel behavior be maintained in a cascade section of larger diameter. This LDRD proceeded in 2 distinct phases. The original plan for the LDRD was to develop a promising switch concept and then design, build, and test a moderate scale switch which would demonstrate the key features of the concept. In phase I, a switch concept which meet all electrical design criteria and had a calculated inductance of 150 nH was developed. A 1.5 MV test switch was designed and fabrication was initiated. The LDRD was then redirected due to budgetary concerns. The fabrication of the switch was halted and the focus of the LDRD was shifted to small scale experiments designed to answer the key technical question concerning multi-channel behavior. In phase II, the Multi-channel switch test bed (MCST) was designed and constructed. The purpose of MCST was to provide a versatile, fast turn around facility for the study the multi-channel electrical breakdown behavior of a ZR type cascade switch gap in a parameter space near that of a ZR LTS. Parameter scans on source impedance, gap tilt, gap spacing and

  12. A radiation hard vacuum switch

    Science.gov (United States)

    Boettcher, G.E.

    1988-07-19

    A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction. 3 figs.

  13. Ru-Os dyads based on a mixed bipyridine-terpyridine bridging ligand: modulation of the rate of energy transfer and pH-induced luminescence switching in the infrared domain.

    Science.gov (United States)

    Bar, Manoranjan; Maity, Dinesh; Deb, Sourav; Das, Shyamal; Baitalik, Sujoy

    2017-10-03

    A series of heterobimetallic complexes of compositions [(bpy/phen) 2 Ru(dipy-Hbzim-tpy)Os (tpy-PhCH 3 /H 2 pbbzim)] 4+ (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, tpy-PhCH 3 = 4'-(4-methylphenyl)-2,2':6',2''-terpyridine and H 2 pbbzim = 2,6-bis(benzimidazole-2-yl)pyridine)), derived from a heteroditopic bpy-tpy bridging ligand, were synthesized and thoroughly characterized in this work. The heterometallic complexes exhibit two successive one-electron reversible metal-centered oxidations corresponding to Os II /Os III at lower potential and Ru II /Ru III at higher potential. All the four dyads exhibit very intense, ligand centered absorption bands in the UV region and moderately intense MLCT bands in the visible region. The dyads also show intense infrared emission with the emission maximum spanning between 734 nm and 775 nm with reasonably long room temperature lifetimes varying between 30 ns and 104 ns. Both steady state and time resolved luminescence spectroscopic investigations indicate that efficient and fast intramolecular energy transfer from the 3 MLCT state of the Ru(ii) center to the Os-center takes place in all the four dyads. In addition, the rate of energy transfer was found to depend on the terminal ligand on the Os-site. Due to the presence of a number of imidazole NH protons in the dyads, significant modulation of both the ground and excited state properties of the complexes was made possible by varying the pH of the solution. By varying the terminal ligand, pH-induced "on-off", "off-off-on" and "on-off-on" emission switching of the complexes was nicely demonstrated in the infrared region.

  14. Sequential multi-channel OCT in the retina using high-speed fiber optic switches

    Science.gov (United States)

    Wartak, Andreas; Augustin, Marco; Beer, Florian; Haindl, Richard; Baumann, Bernhard; Pircher, Michael; Hitzenberger, Christoph K.

    2017-07-01

    A sequential multi-channel OCT prototype featuring high-speed fiber optical switches to enable inter A-scan (A-scan rate: 100 kHz) sample arm switching was developed and human retinal image data is presented.

  15. Energy reversible switching from amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.

    2013-08-01

    We report observation of energy reversible switching from amorphous metal based nanoelectromechanical (NEM) switch. For ultra-low power electronics, NEM switches can be used as a complementary switching element in many nanoelectronic system applications. Its inherent zero power consumption because of mechanical detachment is an attractive feature. However, its operating voltage needs to be in the realm of 1 volt or lower. Appropriate design and lower Young\\'s modulus can contribute achieving lower operating voltage. Therefore, we have developed amorphous metal with low Young\\'s modulus and in this paper reporting the energy reversible switching from a laterally actuated double electrode NEM switch. © 2013 IEEE.

  16. Microfabricated triggered vacuum switch

    Science.gov (United States)

    Roesler, Alexander W [Tijeras, NM; Schare, Joshua M [Albuquerque, NM; Bunch, Kyle [Albuquerque, NM

    2010-05-11

    A microfabricated vacuum switch is disclosed which includes a substrate upon which an anode, cathode and trigger electrode are located. A cover is sealed over the substrate under vacuum to complete the vacuum switch. In some embodiments of the present invention, a metal cover can be used in place of the trigger electrode on the substrate. Materials used for the vacuum switch are compatible with high vacuum, relatively high temperature processing. These materials include molybdenum, niobium, copper, tungsten, aluminum and alloys thereof for the anode and cathode. Carbon in the form of graphitic carbon, a diamond-like material, or carbon nanotubes can be used in the trigger electrode. Channels can be optionally formed in the substrate to mitigate against surface breakdown.

  17. Switching power supply

    Science.gov (United States)

    Mihalka, A.M.

    1984-06-05

    The invention is a repratable capacitor charging, switching power supply. A ferrite transformer steps up a dc input. The transformer primary is in a full bridge configuration utilizing power MOSFETs as the bridge switches. The transformer secondary is fed into a high voltage, full wave rectifier whose output is connected directly to the energy storage capacitor. The transformer is designed to provide adequate leakage inductance to limit capacitor current. The MOSFETs are switched to the variable frequency from 20 to 50 kHz to charge a capacitor from 0.6 kV. The peak current in a transformer primary and secondary is controlled by increasing the pulse width as the capacitor charges. A digital ripple counter counts pulses and after a preselected desired number is reached an up-counter is clocked.

  18. Optical computer switching network

    Science.gov (United States)

    Clymer, B.; Collins, S. A., Jr.

    1985-01-01

    The design for an optical switching system for minicomputers that uses an optical spatial light modulator such as a Hughes liquid crystal light valve is presented. The switching system is designed to connect 80 minicomputers coupled to the switching system by optical fibers. The system has two major parts: the connection system that connects the data lines by which the computers communicate via a two-dimensional optical matrix array and the control system that controls which computers are connected. The basic system, the matrix-based connecting system, and some of the optical components to be used are described. Finally, the details of the control system are given and illustrated with a discussion of timing.

  19. Switching characteristics of microplasmas in a planar electrode gap

    International Nuclear Information System (INIS)

    Rahaman, Hasibur; Lee, Byung-Joon; Petzenhauser, Isfried; Frank, Klaus; Urban, Juergen; Stark, Robert

    2007-01-01

    Microplasmas at high pressure have been the authors' special interest for its practical relevance to the development of a switch. They concentrated on repetitive switching with a possibility to exceed the up to now known values for plasma closing switches and simultaneously maintaining a subnanosecond rise time of the switched pulses at a load. They examined several parameters for this purpose such as the electrode gap spacing, the electrode geometry, the gas type, the gas pressure, and including the applied voltage and current rating to operate these plasmas

  20. Smooth invariant densities for random switching on the torus

    Science.gov (United States)

    Bakhtin, Yuri; Hurth, Tobias; Lawley, Sean D.; Mattingly, Jonathan C.

    2018-04-01

    We consider a random dynamical system obtained by switching between the flows generated by two smooth vector fields on the 2d-torus, with the random switchings happening according to a Poisson process. Assuming that the driving vector fields are transversal to each other at all points of the torus and that each of them allows for a smooth invariant density and no periodic orbits, we prove that the switched system also has a smooth invariant density, for every switching rate. Our approach is based on an integration by parts formula inspired by techniques from Malliavin calculus.

  1. Optical Packet Switching Demostrator

    DEFF Research Database (Denmark)

    Mortensen, Brian Bach; Berger, Michael Stübert

    2002-01-01

    In the IST project DAVID (data and voice integration over DWDM) work is carried out defining possible architectures of future optical packet switched networks. The feasibility of the architecture is to be verified in a demonstration set-up. This article describes the demonstrator set-up and the m......In the IST project DAVID (data and voice integration over DWDM) work is carried out defining possible architectures of future optical packet switched networks. The feasibility of the architecture is to be verified in a demonstration set-up. This article describes the demonstrator set...

  2. Plasma Switch Development.

    Science.gov (United States)

    1984-06-08

    ACCION NO. 3. RCIPIENT’S CATALOG NUMBER 4. TITLE (and Subtitle) 5. TYPE OF REPORT & PERIOD COVERED PLASMA SWITCH DEVELOPMENT Final Report: 02/26/82 thru...with an inductive energy store. At present, the are summarized state-of-he- art of high-power repetitive opening or doming switches is limited to...Alexandria, VA 22304. Figure 7 Is a circuit diagram of the proposed system. The desired load pulse parameters art -100- e References 1. R.D. Ford, 0. Jenkins

  3. Bearingless switched reluctance motor

    Science.gov (United States)

    Morrison, Carlos R. (Inventor)

    2004-01-01

    A switched reluctance motor has a stator with a first set of poles directed toward levitating a rotor horizontally within the stator. A disc shaped portion of a hybrid rotor is affected by the change in flux relative to the current provided at these levitation poles. A processor senses the position of the rotor and changes the flux to move the rotor toward center of the stator. A second set of poles of the stator are utilized to impart torque upon a second portion of the rotor. These second set of poles are driven in a traditional switched reluctance manner by the processor.

  4. Photoconductive switch enhancements for use in Blumlein pulse generators

    International Nuclear Information System (INIS)

    Davanloo, F.; Park, H.; Collins, C. B.; Agee, F. J.

    1999-01-01

    Stacked Blumlein pulse generators developed at the University of Texas at Dallas have produced high-power waveforms with risetimes and repetition rates in the range of 0.2-50 ns and 1-300 Hz, respectively, using a conventional thyratron, spark gap or photoconductive switch. Adaptation of the design has enabled the stacked Blumleins to produce 80 MW, nanosecond pulses with risetimes better than 200 ps into nominally matched loads. The device has a compact line geometry and is commutated by a single GaAs photoconductive switch triggered by a low power laser diode array. Our current investigations involve the switch characteristics that affect the broadening of the current channels in the avalanche, pre-avalanche seedings, the switch lifetime and the durability. This report presents the progress toward improving the GaAs switch operation and lifetime in stacked Blumlein pulsers. Advanced switch treatments including diamond film overcoating are implemented and discussed

  5. Ultrafast gas switching experiments

    International Nuclear Information System (INIS)

    Frost, C.A.; Martin, T.H.; Patterson, P.E.; Rinehart, L.F.; Rohwein, G.J.; Roose, L.D.; Aurand, J.F.; Buttram, M.T.

    1993-01-01

    We describe recent experiments which studied the physics of ultrafast gas breakdown under the extreme overvoltages which occur when a high pressure gas switch is pulse charged to hundreds of kV in 1 ns or less. The highly overvolted peaking gaps produce powerful electromagnetic pulses with risetimes Khz at > 100 kV/m E field

  6. Search and switching costs

    NARCIS (Netherlands)

    Siekman, Wilhelm Henricus

    2016-01-01

    This thesis analyses markets with search and with switching costs. It provides insights in several important issues in search markets, including how loss aversion may affect consumer behavior and firm conduct, and how prices, welfare, and profits may change when an intermediating platform orders

  7. The Octopus switch

    NARCIS (Netherlands)

    Havinga, Paul J.M.

    2000-01-01

    This chapter1 discusses the interconnection architecture of the Mobile Digital Companion. The approach to build a low-power handheld multimedia computer presented here is to have autonomous, reconfigurable modules such as network, video and audio devices, interconnected by a switch rather than by a

  8. Stochastic Switching Dynamics

    DEFF Research Database (Denmark)

    Simonsen, Maria

    mode control. It is investigated how to understand and interpret solutions to models of switched systems, which are exposed to discontinuous dynamics and uncertainties (primarily) in the form of white noise. The goal is to gain knowledge about the performance of the system by interpreting the solution...

  9. Molecular Rotors as Switches

    Directory of Open Access Journals (Sweden)

    Kang L. Wang

    2012-08-01

    Full Text Available The use of a functional molecular unit acting as a state variable provides an attractive alternative for the next generations of nanoscale electronics. It may help overcome the limits of conventional MOSFETd due to their potential scalability, low-cost, low variability, and highly integratable characteristics as well as the capability to exploit bottom-up self-assembly processes. This bottom-up construction and the operation of nanoscale machines/devices, in which the molecular motion can be controlled to perform functions, have been studied for their functionalities. Being triggered by external stimuli such as light, electricity or chemical reagents, these devices have shown various functions including those of diodes, rectifiers, memories, resonant tunnel junctions and single settable molecular switches that can be electronically configured for logic gates. Molecule-specific electronic switching has also been reported for several of these device structures, including nanopores containing oligo(phenylene ethynylene monolayers, and planar junctions incorporating rotaxane and catenane monolayers for the construction and operation of complex molecular machines. A specific electrically driven surface mounted molecular rotor is described in detail in this review. The rotor is comprised of a monolayer of redox-active ligated copper compounds sandwiched between a gold electrode and a highly-doped P+ Si. This electrically driven sandwich-type monolayer molecular rotor device showed an on/off ratio of approximately 104, a read window of about 2.5 V, and a retention time of greater than 104 s. The rotation speed of this type of molecular rotor has been reported to be in the picosecond timescale, which provides a potential of high switching speed applications. Current-voltage spectroscopy (I-V revealed a temperature-dependent negative differential resistance (NDR associated with the device. The analysis of the device

  10. Switching between intravenous and subcutaneous trastuzumab

    DEFF Research Database (Denmark)

    Gligorov, Joseph; Curigliano, Giuseppe; Müller, Volkmar

    2017-01-01

    AIM: To assess the safety and tolerability of switching between subcutaneous (SC) and intravenous (IV) trastuzumab in the PrefHer study (NCT01401166). PATIENTS AND METHODS: Patients with HER2-positive early breast cancer completed (neo)adjuvant chemotherapy and were randomised to receive four....... Rates of clinically important events, including grade ≥3 AEs, serious AEs, AEs leading to study drug discontinuation and cardiac AEs, were low and similar between treatment arms (safety signals for trastuzumab were observed. CONCLUSIONS: PrefHer revealed...... that switching from IV to SC trastuzumab (hand-held syringe or SID) or vice versa did not impact the known safety profile of trastuzumab....

  11. Switching model photovoltaic pumping system

    Science.gov (United States)

    Anis, Wagdy R.; Abdul-Sadek Nour, M.

    Photovoltaic (PV) pumping systems are widely used due to their simplicity, high reliability and low cost. A directly-coupled PV pumping system is the most reliable and least-cost PV system. The d.c. motor-pump group is not, however, working at its optimum operating point. A battery buffered PV pumping system introduces a battery between the PV array and the d.c. motor-pump group to ensure that the motor-pump group is operating at its optimum point. The size of the battery storage depends on system economics. If the battery is fully charged while solar radiation is available, the battery will discharge through the load while the PV array is disconnected. Hence, a power loss takes place. To overcome the above mentioned difficulty, a switched mode PV pumping is proposed. When solar radiation is available and the battery is fully charged, the battery is disconnected and the d.c. motor-pump group is directly coupled to the PV array. To avoid excessive operating voltage for the motor, a part of the PV array is switched off to reduce the voltage. As a result, the energy loss is significantly eliminated. Detailed analysis of the proposed system shows that the discharged water increases by about 10% when compared with a conventional battery-buffered system. The system transient performance just after the switching moment shows that the system returns to a steady state in short period. The variations in the system parameters lie within 1% of the rated values.

  12. Control synthesis of switched systems

    CERN Document Server

    Zhao, Xudong; Niu, Ben; Wu, Tingting

    2017-01-01

    This book offers its readers a detailed overview of the synthesis of switched systems, with a focus on switching stabilization and intelligent control. The problems investigated are not only previously unsolved theoretically but also of practical importance in many applications: voltage conversion, naval piloting and navigation and robotics, for example. The book considers general switched-system models and provides more efficient design methods to bring together theory and application more closely than was possible using classical methods. It also discusses several different classes of switched systems. For general switched linear systems and switched nonlinear systems comprising unstable subsystems, it introduces novel ideas such as invariant subspace theory and the time-scheduled Lyapunov function method of designing switching signals to stabilize the underlying systems. For some typical switched nonlinear systems affected by various complex dynamics, the book proposes novel design approaches based on inte...

  13. Switching between phenotypes and population extinction

    Science.gov (United States)

    Lohmar, Ingo; Meerson, Baruch

    2011-11-01

    Many types of bacteria can survive under stress by switching stochastically between two different phenotypes: the “normals” who multiply fast, but are vulnerable to stress, and the “persisters” who hardly multiply, but are resilient to stress. Previous theoretical studies of such bacterial populations have focused on the fitness: the asymptotic rate of unbounded growth of the population. Yet for an isolated population of established (and not very large) size, a more relevant measure may be the population extinction risk due to the interplay of adverse extrinsic variations and intrinsic noise of birth, death and switching processes. Applying a WKB approximation to the pertinent master equation of such a two-population system, we quantify the extinction risk, and find the most likely path to extinction under both favorable and adverse conditions. Analytical results are obtained both in the biologically relevant regime when the switching is rare compared with the birth and death processes, and in the opposite regime of frequent switching. We show that rare switches are most beneficial in reducing the extinction risk.

  14. Submicrosecond Power-Switching Test Circuit

    Science.gov (United States)

    Folk, Eric N.

    2006-01-01

    A circuit that changes an electrical load in a switching time shorter than 0.3 microsecond has been devised. This circuit can be used in testing the regulation characteristics of power-supply circuits . especially switching power-converter circuits that are supposed to be able to provide acceptably high degrees of regulation in response to rapid load transients. The combination of this power-switching circuit and a known passive constant load could be an attractive alternative to a typical commercially available load-bank circuit that can be made to operate in nominal constant-voltage, constant-current, and constant-resistance modes. The switching provided by a typical commercial load-bank circuit in the constant-resistance mode is not fast enough for testing of regulation in response to load transients. Moreover, some test engineers do not trust the test results obtained when using commercial load-bank circuits because the dynamic responses of those circuits are, variously, partly unknown and/or excessively complex. In contrast, the combination of this circuit and a passive constant load offers both rapid switching and known (or at least better known) load dynamics. The power-switching circuit (see figure) includes a signal-input section, a wide-hysteresis Schmitt trigger that prevents false triggering in the event of switch-contact bounce, a dual-bipolar-transistor power stage that drives the gate of a metal oxide semiconductor field-effect transistor (MOSFET), and the MOSFET, which is the output device that performs the switching of the load. The MOSFET in the specific version of the circuit shown in the figure is rated to stand off a potential of 100 V in the "off" state and to pass a current of 20 A in the "on" state. The switching time of this circuit (the characteristic time of rise or fall of the potential at the drain of the MOSFET) is .300 ns. The circuit can accept any of three control inputs . which one depending on the test that one seeks to perform: a

  15. Review of opening switch technology

    International Nuclear Information System (INIS)

    Kristiansen, M.; Schoenbach, K.M.; Schaefer, G.

    1984-01-01

    Review of opening switch technology is given. Classification of open switches applied in pulsed power technology is presented. The most familiar opening switches are fuses. It is shown that a strong oxidizer (H 2 O 2 in water), especially in combination with wires of Al, increases the maximum voltage. Thermally driven opening switches are the result of attempts to achive the speed and economy of fuse opening switches but with added advantage of repetitive operation. The search for coordinate materials for this type of opening switch is in its infancy and it is difficult to predict how successful such a switch may be. Explosive opening switches offer the possibility of precise timing and permit the delay before explosion to be controlled independently of current flowing through the switch. Plasma guns, dense plasma focus and MHD switches are also considered. Diffuse discharge opening switches are attractive for repetitive operation. The plasma erosion switch operates on a very short time scale of 10 ns to 100 ns, both to regard to conduction and opening times

  16. Abacus switch: a new scalable multicast ATM switch

    Science.gov (United States)

    Chao, H. Jonathan; Park, Jin-Soo; Choe, Byeong-Seog

    1995-10-01

    This paper describes a new architecture for a scalable multicast ATM switch from a few tens to thousands of input ports. The switch, called Abacus switch, has a nonblocking memoryless switch fabric followed by small switch modules at the output ports; the switch has input and output buffers. Cell replication, cell routing, output contention resolution, and cell addressing are all performed distributedly in the Abacus switch so that it can be scaled up to thousnads input and output ports. A novel algorithm has been proposed to resolve output port contention while achieving input and output ports. A novel algorithm has been proposed to reolve output port contention while achieving input buffers sharing, fairness among the input ports, and multicast call splitting. The channel grouping concept is also adopted in the switch to reduce the hardware complexity and improve the switch's throughput. The Abacus switch has a regular structure and thus has the advantages of: 1) easy expansion, 2) relaxed synchronization for data and clock signals, and 3) building the switch fabric using existing CMOS technology.

  17. A Simulator of Periodically Switching Channels for Power Line Communications

    Science.gov (United States)

    Hayasaki, Taro; Umehara, Daisuke; Denno, Satoshi; Morikura, Masahiro

    An indoor power line is one of the most attractive media for in-home networks. However, there are many technical problems for achieving in-home power line communication (PLC) with high rate and high reliability. One of such problem is the degradation in the performance of the in-home PLC caused by periodically time-varying channel responses, particularly when connecting the switching power supply equipment. We present a measurement method for power line channel responses and reveal the switching of the channel responses synchronized with power-frequency voltage when connecting switching power supply equipment in sending or receiving outlets. In this paper, we term them periodically switching channel responses. The performance of PLC adapters is seriously affected by the periodically switching channel responses. Therefore, we provide a modeling of the periodically switching channel responses by using finite impulse response (FIR) filters with a shared channel memory and construct a simulator for in-home power line channels including the periodically switching channel responses in order to evaluate the various communication systems through the power line. We present the validity of the proposed simulator through the performance evaluation of OFDM/64QAM over periodically switching channels with additive white Gaussian noise. Furthermore, we evaluate the influence of the periodically switching channel responses on the communication quality of a time-invariant modulation scheme by using the proposed simulator.

  18. On life assessment of high reliability high power optical switch

    Science.gov (United States)

    Xu, Yuanjian; Chu, Peter

    2014-09-01

    High data rate and long range free space lasercom links require multi-watt optical transmitter power, which creates a need for high power redundancy switches to ensure high payload reliability. A high power optical switch (HPOS) with less than 0.15 dB loss and capable of switching more than 40 watts of optical power in a single mode fiber has been previously demonstrated in the Transformational Satellite Communication System program. Prototype switches, in either 1x2 or 2x2 configuration, have been subjected to pyro-shock test, vibration test, and vacuum operation. These switches showed no performance degradation as a result of these tests. Three prototypes went through 60,000 35-watt switching cycles and over 30 million low power switching cycles, and the switches showed no mechanical failure. The HPOS life is about 3.2 million switching cycles with a definition of 3-dB degradation in on/off extinction ratio, which is well suited for space applications.

  19. Optical fiber switch

    Science.gov (United States)

    Early, James W.; Lester, Charles S.

    2002-01-01

    Optical fiber switches operated by electrical activation of at least one laser light modulator through which laser light is directed into at least one polarizer are used for the sequential transport of laser light from a single laser into a plurality of optical fibers. In one embodiment of the invention, laser light from a single excitation laser is sequentially transported to a plurality of optical fibers which in turn transport the laser light to separate individual remotely located laser fuel ignitors. The invention can be operated electro-optically with no need for any mechanical or moving parts, or, alternatively, can be operated electro-mechanically. The invention can be used to switch either pulsed or continuous wave laser light.

  20. Beyond the switch

    DEFF Research Database (Denmark)

    Aliakseyeu, Dzmitry; Meerbeek, Bernt; Mason, Jon

    2014-01-01

    The commercial introduction of connected lighting that can be integrated with sensors and other devices is opening up new possibilities in creating responsive and intelligent environments. The role of lighting in such systems goes beyond simply functional illumination. In part due to the large...... is to explore new ways of interacting with light where lighting can not only be switched on or off, but is an intelligent system embedded in the environment capable of creating a variety of effects. The connectivity between multiple systems and other ecosystems, for example when transitioning from your home...... and established lighting network, and with the advent of the LED, new types of lighting output are now possible. However, the current approach for controlling such systems is to simply replace the light switch with a somewhat more sophisticated smartphone-based remote control. The focus of this workshop...

  1. Laser activated superconducting switch

    International Nuclear Information System (INIS)

    Wolf, A.A.

    1976-01-01

    A superconducting switch or bistable device is described consisting of a superconductor in a cryogen maintaining a temperature just below the transition temperature, having a window of the proper optical frequency band for passing a laser beam which may impinge on the superconductor when desired. The frequency of the laser is equal to or greater than the optical absorption frequency of the superconducting material and is consistent with the ratio of the gap energy of the switch material to Planck's constant, to cause depairing of electrons, and thereby normalize the superconductor. Some embodiments comprise first and second superconducting metals. Other embodiments feature the two superconducting metals separated by a thin film insulator through which the superconducting electrons tunnel during superconductivity

  2. Coulomb Blockade Plasmonic Switch.

    Science.gov (United States)

    Xiang, Dao; Wu, Jian; Gordon, Reuven

    2017-04-12

    Tunnel resistance can be modulated with bias via the Coulomb blockade effect, which gives a highly nonlinear response current. Here we investigate the optical response of a metal-insulator-nanoparticle-insulator-metal structure and show switching of a plasmonic gap from insulator to conductor via Coulomb blockade. By introducing a sufficiently large charging energy in the tunnelling gap, the Coulomb blockade allows for a conductor (tunneling) to insulator (capacitor) transition. The tunnelling electrons can be delocalized over the nanocapacitor again when a high energy penalty is added with bias. We demonstrate that this has a huge impact on the plasmonic resonance of a 0.51 nm tunneling gap with ∼70% change in normalized optical loss. Because this structure has a tiny capacitance, there is potential to harness the effect for high-speed switching.

  3. Present and Future of Semiconductor Pulsed Power Generator ˜Role of Power Semiconductor Devices in Plasma Research˜ 5.High-Repetition-Rate Marx Generator Using Thyristor Switches

    Science.gov (United States)

    Maeyama, Mitsuaki

    The Static Marx Generatoris a high-voltage impulse generator using semiconductor switches that borrow their simple trigger operation from the conventional Marx Generator. This commentary presents the principle of successive trigger operation, the high-speed and high-efficiency charging mechanism used in this Static Marx Generator circuit system, and the typical properties of the voltage amplification ratio, i.e. the rise time and charging efficiency.

  4. Practical switching power supply design

    CERN Document Server

    Brown, Martin C

    1990-01-01

    Take the ""black magic"" out of switching power supplies with Practical Switching Power Supply Design! This is a comprehensive ""hands-on"" guide to the theory behind, and design of, PWM and resonant switching supplies. You'll find information on switching supply operation and selecting an appropriate topology for your application. There's extensive coverage of buck, boost, flyback, push-pull, half bridge, and full bridge regulator circuits. Special attention is given to semiconductors used in switching supplies. RFI/EMI reduction, grounding, testing, and safety standards are also deta

  5. Python Switch Statement

    Directory of Open Access Journals (Sweden)

    2008-06-01

    Full Text Available The Python programming language does not have a built in switch/case control structure as found in many other high level programming languages. It is thought by some that this is a deficiency in the language, and the control structure should be added. This paper demonstrates that not only is the control structure not needed, but that the methods available in Python are more expressive than built in case statements in other high level languages.

  6. Mathematical solutions of rate equations of a laser-diode end-pumped passively Q-switched and mode locked Nd-laser with Cr4+:YAG polarized saturable absorber

    International Nuclear Information System (INIS)

    Abdul Ghani, B.; Hammadi, M.

    2012-01-01

    The intracavity frequency-doubling (IFD) of a simultaneous passively Q-switched mode-locked diode-pumped Nd 3 + - laser is studied with a polarized isotropic Cr 4 +: YAG saturable absorber. A general recurrence formula for the mode-locked pulses under the Q-switched envelope at fundamental wavelength has been reconstructed in order to analyze the temporal shape behavior of a single Q-switched envelope with mode-locking pulse trains. This formula has been derived taking into account the impact of the IFD and polarized Cr 4 +: YAG saturable absorber.The presented mathematical model describes the self-induced anisotropy appeared in the polarized Cr 4 +: YAG in the nonlinear stage of the giant pulse formation. For the anisotropic Nd 3 +: YVO 4 active medium, the generated polarized waves are assumed to be fixed through the lasing cycle. Besides, the maximum absorber initial transmission and the minimum mirror reflectivity values have been determined from the second threshold criterion. The calculated numerical results demonstrate the impact of the variation of the input laser parameters (rotational angle of the polarized crystal, absorber initial transmission and the output mirror reflectivity) on the characteristics of the output laser pulse (SH peak power, pulse width, pulse duration and shift pulse position of central mode). The calculated numerical results in this work is in good qualitative and quantitative agreement with the available experimental data reported in the references. (author)

  7. Nanomechanics of flexoelectric switching

    Science.gov (United States)

    Očenášek, J.; Lu, H.; Bark, C. W.; Eom, C. B.; Alcalá, J.; Catalan, G.; Gruverman, A.

    2015-07-01

    We examine the phenomenon of flexoelectric switching of polarization in ultrathin films of barium titanate induced by a tip of an atomic force microscope (AFM). The spatial distribution of the tip-induced flexoelectricity is computationally modeled both for perpendicular mechanical load (point measurements) and for sliding load (scanning measurements), and compared with experiments. We find that (i) perpendicular load does not lead to stable ferroelectric switching in contrast to the load applied in the sliding contact load regime, due to nontrivial differences between the strain distributions in both regimes: ferroelectric switching for the perpendicular load mode is impaired by a strain gradient inversion layer immediately underneath the AFM tip; while for the sliding load regime, domain inversion is unimpaired within a greater material volume subjected to larger values of the mechanically induced electric field that includes the region behind the sliding tip; (ii) beyond a relatively small value of an applied force, increasing mechanical pressure does not increase the flexoelectric field inside the film, but results instead in a growing volume of the region subjected to such field that aids domain nucleation processes; and (iii) the flexoelectric coefficients of the films are of the order of few nC/m, which is much smaller than for bulk BaTi O3 ceramics, indicating that there is a "flexoelectric size effect" that mirrors the ferroelectric one.

  8. "Platform switching": Serendipity

    Directory of Open Access Journals (Sweden)

    N Kalavathy

    2014-01-01

    Full Text Available Implant dentistry is the latest developing field in terms of clinical techniques, research, material science and oral rehabilitation. Extensive work is being done to improve the designing of implants in order to achieve better esthetics and function. The main drawback with respect to implant restoration is achieving good osseointegration along with satisfactory stress distribution, which in turn will improve the prognosis of implant prosthesis by reducing the crestal bone loss. Many concepts have been developed with reference to surface coating of implants, surgical techniques for implant placement, immediate and delayed loading, platform switching concept, etc. This article has made an attempt to review the concept of platform switching was in fact revealed accidentally due to the nonavailability of the abutment appropriate to the size of the implant placed. A few aspect of platform switching, an upcoming idea to reduce crestal bone loss have been covered. The various methods used for locating and preparing the data were done through textbooks, Google search and related articles.

  9. Safe LPV Controller Switching

    DEFF Research Database (Denmark)

    Trangbæk, K

    2011-01-01

    Before switching to a new controller it is crucial to assure that the new closed loop will be stable. In this paper it is demonstrated how stability can be checked with limited measurement data available from the current closed loop. The paper extends an existing method to linear parameter varying...... plants and controllers. Rather than relying on frequency domain methods as done in the LTI case, it is shown how to use standard LPV system identification methods. It is furthermore shown how to include model uncertainty to robustify the results. By appropriate filtering, it is only necessary to evaluate...

  10. Safe LPV Controller Switching

    DEFF Research Database (Denmark)

    Trangbæk, K

    2010-01-01

    Before switching to a new controller it is crucial to assure that the new closed loop will be stable. In this paper it is demonstrated how stability can be checked with limited measurement data available from the current closed loop. The paper extends an existing method to linear parameter varying...... plants and controllers. Rather than relying on frequency domain methods as done in the LTI case, it is shown how to use standard LPV system identification methods. By identifying a filtered closed-loop operator rather than directly identifying the plant, more reliable results are obtained....

  11. DC switching regulated power supply for driving an inductive load

    Science.gov (United States)

    Dyer, George R.

    1986-01-01

    A power supply for driving an inductive load current from a dc power supply hrough a regulator circuit including a bridge arrangement of diodes and switching transistors controlled by a servo controller which regulates switching in response to the load current to maintain a selected load current. First and second opposite legs of the bridge are formed by first and second parallel-connected transistor arrays, respectively, while the third and fourth legs of the bridge are formed by appropriately connected first and second parallel connected diode arrays, respectively. The regulator may be operated in three "stages" or modes: (1) For current runup in the load, both first and second transistor switch arrays are turned "on" and current is supplied to the load through both transistor arrays. (2) When load current reaches the desired level, the first switch is turned "off", and load current "flywheels" through the second switch array and the fourth leg diode array connecting the second switch array in series with the load. Current is maintained by alternating between modes 1 and 2 at a suitable duty cycle and switching rate set by the controller. (3) Rapid current rundown is accomplished by turning both switch arrays "off", allowing load current to be dumped back into the source through the third and fourth diode arrays connecting the source in series opposition with the load to recover energy from the inductive load. The three operating states are controlled automatically by the controller.

  12. Neuromorphic atomic switch networks.

    Directory of Open Access Journals (Sweden)

    Audrius V Avizienis

    Full Text Available Efforts to emulate the formidable information processing capabilities of the brain through neuromorphic engineering have been bolstered by recent progress in the fabrication of nonlinear, nanoscale circuit elements that exhibit synapse-like operational characteristics. However, conventional fabrication techniques are unable to efficiently generate structures with the highly complex interconnectivity found in biological neuronal networks. Here we demonstrate the physical realization of a self-assembled neuromorphic device which implements basic concepts of systems neuroscience through a hardware-based platform comprised of over a billion interconnected atomic-switch inorganic synapses embedded in a complex network of silver nanowires. Observations of network activation and passive harmonic generation demonstrate a collective response to input stimulus in agreement with recent theoretical predictions. Further, emergent behaviors unique to the complex network of atomic switches and akin to brain function are observed, namely spatially distributed memory, recurrent dynamics and the activation of feedforward subnetworks. These devices display the functional characteristics required for implementing unconventional, biologically and neurally inspired computational methodologies in a synthetic experimental system.

  13. Modeling of rf MEMS switches

    Science.gov (United States)

    Robertson, Barbara; Ho, Fat D.; Hudson, Tracy D.

    2001-10-01

    The microelectromechanical system (MEMS) switch offers many benefits in radio frequency (RF) applications. These benefits include low insertion loss, high quality factor (Q), low power, RF isolation, and low cost. The ability to manufacture mechanical switches on a chip with electronics can lead to higher functionality, such as single-chip arrays, and smart switches. The MEMS switch is also used as a building block in devices such as phase shifters, filters, and switchable antenna elements. The MEMS designer needs models of these basic elements in order to incorporate them into their applications. The objective of this effort is to develop lumped element models for MEMS RF switches, which are incorporated into a CAD software. Tanner Research Inc.'s Electronic Design Automation (EDA) software is being used to develop a suite of mixed-signal RF switch models. The suite will include switches made from cantilever beams and fixed-fixed beams. The switches may be actuated by electrostatic, piezoelectric or electromagnetic forces. The effort presented in this paper concentrates on switches actuated by electrostatic forces. The lumped element models use a current-force electrical-mechanical analogy. Finite element modeling and device testing will be used to verify the Tanner models. The effects of materials, geometries, temperature, fringing fields, and mounting geometries are considered.

  14. Software Switching for Data Acquisition

    CERN Multimedia

    CERN. Geneva; Malone, David

    2016-01-01

    In this talk we discuss the feasibility of replacing telecom-class routers with a topology of commodity servers acting as software switches in data acquisition. We extend the popular software switch, Open vSwitch, with a dedicated, throughput-oriented buffering mechanism. We compare the performance under heavy many-to-one congestion to typical Ethernet switches and evaluate the scalability when building larger topologies, exploiting the integration with software-defined networking technologies. Please note that David Malone will speak on behalf of Grzegorz Jereczek.

  15. Recent developments in switching theory

    CERN Document Server

    Mukhopadhyay, Amar

    2013-01-01

    Electrical Science Series: Recent Developments in Switching Theory covers the progress in the study of the switching theory. The book discusses the simplified proof of Post's theorem on completeness of logic primitives; the role of feedback in combinational switching circuits; and the systematic procedure for the design of Lupanov decoding networks. The text also describes the classical results on counting theorems and their application to the classification of switching functions under different notions of equivalence, including linear and affine equivalences. The development of abstract har

  16. 47 CFR 61.26 - Tariffing of competitive interstate switched exchange access services.

    Science.gov (United States)

    2010-10-01

    ... switched exchange access services that prices those services above the higher of: (1) The rate charged for... equivalent of the ILEC interstate exchange access services typically associated with following rate elements... switched exchange access services shall mean the composite, per-minute rate for these services, including...

  17. Gel catalysts that switch on and off

    Science.gov (United States)

    Wang, Guoqiang; Kuroda, Kenichi; Enoki, Takashi; Grosberg, Alexander; Masamune, Satoru; Oya, Taro; Takeoka, Yukikazu; Tanaka, Toyoichi

    2000-01-01

    We report development of a polymer gel with a catalytic activity that can be switched on and off when the solvent composition is changed. The gel consists of two species of monomers. The major component, N-isopropylacrylamide, makes the gel swell and shrink in response to a change in composition of ethanol/water mixtures. The minor component, vinylimidazole, which is capable of catalysis, is copolymerized into the gel network. The reaction rate for catalytic hydrolysis of p-nitrophenyl caprylate was small when the gel was swollen. In contrast, when the gel was shrunken, the reaction rate increased 5 times. The activity changes discontinuously as a function of solvent composition, thus the catalysis can be switched on and off by an infinitesimal change in solvent composition. The kinetics of catalysis by the gel in the shrunken state is well described by the Michaelis–Menten formula, indicating that the absorption of the substrate by the hydrophobic environment created by the N-isopropylacrylamide polymer in the shrunken gel is responsible for enhancement of catalytic activity. In the swollen state, the rate vs. active site concentration is linear, indicating that the substrate absorption is not a primary factor determining the kinetics. Catalytic activity of the gel is studied for substrates with various alkyl chain lengths; of those studied the switching effect is most pronounced for p-nitrophenyl caprylate. PMID:10954747

  18. Hybrid switch for resonant power converters

    Science.gov (United States)

    Lai, Jih-Sheng; Yu, Wensong

    2014-09-09

    A hybrid switch comprising two semiconductor switches connected in parallel but having different voltage drop characteristics as a function of current facilitates attainment of zero voltage switching and reduces conduction losses to complement reduction of switching losses achieved through zero voltage switching in power converters such as high-current inverters.

  19. Study of all optical switching behaviour in semiconductor microresonator with nano-active layer

    International Nuclear Information System (INIS)

    Kheradmand, R; Aryan, H

    2010-01-01

    In this paper the behaviour of carriers in spontaneous patterns formation and patterns switching has been studied. Results demonstrate that with increasing length of cavity the range of required input field amplitude for patterns formation increased slightly and also the minimum perturbation coefficient for switching decreased greatly. Increasing nonradiative recombination rate of carriers about ten percent appeared that required input field amplitude for patterns formation raised more than before, albeit the minimum perturbation coefficient for switching and switching and switching time dose not vary considerably.

  20. Study of all optical switching behaviour in semiconductor microresonator with nano-active layer

    Energy Technology Data Exchange (ETDEWEB)

    Kheradmand, R; Aryan, H, E-mail: r_kheradmand@tabrizu.ac.i, E-mail: aryan86@ms.tabrizu.ac.i [Photonics Group, Research Institute for Applied Physics and Astronomy, Tabriz University, Tabriz (Iran, Islamic Republic of)

    2010-11-01

    In this paper the behaviour of carriers in spontaneous patterns formation and patterns switching has been studied. Results demonstrate that with increasing length of cavity the range of required input field amplitude for patterns formation increased slightly and also the minimum perturbation coefficient for switching decreased greatly. Increasing nonradiative recombination rate of carriers about ten percent appeared that required input field amplitude for patterns formation raised more than before, albeit the minimum perturbation coefficient for switching and switching and switching time dose not vary considerably.

  1. A Radical Switch

    Directory of Open Access Journals (Sweden)

    Alexander Rappaport

    2017-09-01

    Full Text Available Architecture is the most vulnerable part of culture, almost doomed to destruction of its fundamentals, while the rise of its intellectual and creative level is badly needed. However, neither the resort to postmarxist French philosophy nor bringing the results of development of science and technology into architecture, neither computerization nor peculiarities of parametricism and deconstructivism are helpful. It can be stated that in the beginning of the third millennium architecture and architectural education are in stalemate. The way out is in a “radical” switch from comprehension of object space to the time and to the processes of thinking, designing and historical change in professional mentality. The interests must be focused not on the object, but on the process enabling the use of return reflexive strokes as well.

  2. Battery switch for downhole tools

    Science.gov (United States)

    Boling, Brian E.

    2010-02-23

    An electrical circuit for a downhole tool may include a battery, a load electrically connected to the battery, and at least one switch electrically connected in series with the battery and to the load. The at least one switch may be configured to close when a tool temperature exceeds a selected temperature.

  3. Improved switch-resistor packaging

    Science.gov (United States)

    Redmerski, R. E.

    1980-01-01

    Packaging approach makes resistors more accessible and easily identified with specific switches. Failures are repaired more quickly because of improved accessibility. Typical board includes one resistor that acts as circuit breaker, and others are positioned so that their values can be easily measured when switch is operated. Approach saves weight by using less wire and saves valuable panel space.

  4. Task Switching: A PDP Model

    Science.gov (United States)

    Gilbert, Sam J.; Shallice, Tim

    2002-01-01

    When subjects switch between a pair of stimulus-response tasks, reaction time is slower on trial N if a different task was performed on trial N--1. We present a parallel distributed processing (PDP) model that simulates this effect when subjects switch between word reading and color naming in response to Stroop stimuli. Reaction time on "switch…

  5. A CMOS Switched Transconductor Mixer

    NARCIS (Netherlands)

    Klumperink, Eric A.M.; Louwsma, S.M.; Wienk, Gerhardus J.M.; Nauta, Bram

    A new CMOS active mixer topology can operate at low supply voltages by the use of switches exclusively connected to the supply voltages. Such switches require less voltage headroom and avoid gate-oxide reliability problems. Mixing is achieved by exploiting two transconductors with cross-coupled

  6. The Impact of Native State Switching on Protein Sequence Evolution.

    Science.gov (United States)

    Sharir-Ivry, Avital; Xia, Yu

    2017-06-01

    For proteins with a single well-defined native state, protein 3Dstructure is a major determinant of sequence evolution. On the other hand, many proteins adopt multiple, distinct native structures under different conditions ("conformational switches"), yet the impact of such native state switching on protein evolution is not fully understood. Here, we performed a proteome-wide analysis of how protein structure impacts sequence evolution for protein conformational switches in Saccharomyces cerevisiae using pooled analysis of sites with similar packing or burial. We observed a strong linear relationship between residue evolutionary rate and residue burial for conformational switches. In addition, we found that conformational switches evolve significantly and consistently more slowly than proteins with a single native state, even after controlling for degree of residue burial or packing. Next, we focused on proteins that switch conformations upon molecular binding. We found that interfacial residues in these conformational switches evolve more slowly than interfacial residues in proteins with a single native state, and that the bound conformation is a better predictor for residue evolutionary rate than the unbound conformation. Our findings suggest that for conformational switches, the necessity to encode multiple distinct native structures under different conditions imposes strong evolutionary constraints on the entire protein, rather than just a few key residues. Our results provide new insights into the structure-evolution relationship of protein conformational switches. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.

    2013-04-01

    Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

  8. The Influence of Feedback on Task-Switching Performance: A Drift Diffusion Modeling Account

    Directory of Open Access Journals (Sweden)

    Russell Cohen Hoffing

    2018-02-01

    Full Text Available Task-switching is an important cognitive skill that facilitates our ability to choose appropriate behavior in a varied and changing environment. Task-switching training studies have sought to improve this ability by practicing switching between multiple tasks. However, an efficacious training paradigm has been difficult to develop in part due to findings that small differences in task parameters influence switching behavior in a non-trivial manner. Here, for the first time we employ the Drift Diffusion Model (DDM to understand the influence of feedback on task-switching and investigate how drift diffusion parameters change over the course of task switch training. We trained 316 participants on a simple task where they alternated sorting stimuli by color or by shape. Feedback differed in six different ways between subjects groups, ranging from No Feedback (NFB to a variety of manipulations addressing trial-wise vs. Block Feedback (BFB, rewards vs. punishments, payment bonuses and different payouts depending upon the trial type (switch/non-switch. While overall performance was found to be affected by feedback, no effect of feedback was found on task-switching learning. Drift Diffusion Modeling revealed that the reductions in reaction time (RT switch cost over the course of training were driven by a continually decreasing decision boundary. Furthermore, feedback effects on RT switch cost were also driven by differences in decision boundary, but not in drift rate. These results reveal that participants systematically modified their task-switching performance without yielding an overall gain in performance.

  9. Switching Phenomena in a System with No Switches

    Science.gov (United States)

    Preis, Tobias; Stanley, H. Eugene

    2010-02-01

    It is widely believed that switching phenomena require switches, but this is actually not true. For an intriguing variety of switching phenomena in nature, the underlying complex system abruptly changes from one state to another in a highly discontinuous fashion. For example, financial market fluctuations are characterized by many abrupt switchings creating increasing trends ("bubble formation") and decreasing trends ("financial collapse"). Such switching occurs on time scales ranging from macroscopic bubbles persisting for hundreds of days to microscopic bubbles persisting only for a few seconds. We analyze a database containing 13,991,275 German DAX Future transactions recorded with a time resolution of 10 msec. For comparison, a database providing 2,592,531 of all S&P500 daily closing prices is used. We ask whether these ubiquitous switching phenomena have quantifiable features independent of the time horizon studied. We find striking scale-free behavior of the volatility after each switching occurs. We interpret our findings as being consistent with time-dependent collective behavior of financial market participants. We test the possible universality of our result by performing a parallel analysis of fluctuations in transaction volume and time intervals between trades. We show that these financial market switching processes have properties similar to those of phase transitions. We suggest that the well-known catastrophic bubbles that occur on large time scales—such as the most recent financial crisis—are no outliers but single dramatic representatives caused by the switching between upward and downward trends on time scales varying over nine orders of magnitude from very large (≈102 days) down to very small (≈10 ms).

  10. Enhanced temperature-independent magnetoresistance below the ...

    Indian Academy of Sciences (India)

    Introduction. The giant and colossal magnetoresistance (GMR and CMR, respectively) effects in doped manganite films on LaAlO3 substrate grown by pulsed laser deposition (PLD), has greatly ... The SQUID magnetometer was used to measure the magnetization of the film at a field of H = 50 Oe. 3. Results and discussion.

  11. Enhanced temperature-independent magnetoresistance below the ...

    Indian Academy of Sciences (India)

    The sharp peak in the temperature dependence of the resistance corresponding to metal-to-insulator transition (p) has been observed at a temperature of p ... a decrease in magnetization with decreasing temperature up to 5 K below 82 K exhibiting a sort of antiferromagnetic behavior in the low temperature regime ( ...

  12. Enhanced temperature-independent magnetoresistance below the ...

    Indian Academy of Sciences (India)

    tions in the magnetic recording industry [1–3]. The GMR effects considerably larger than those in ... 0.0. 0.5. 1.0. 1.5. 2.0. 2.5. 3.0. 3.5. 4.0. Resistance (M. Ω. ) Figure 1. Temperature dependence of resistance at 0 Oe, 20 kOe and 40 kOe of. LNCMO film. 1090. Pramana – J. Phys., Vol. 58, Nos 5 & 6, May & June 2002 ...

  13. Reliable switching in MRAM and multiferroic logic

    Science.gov (United States)

    Munira, Kamaram; Bandyopadhyay, Supriyo; Atulasimha, Jayasimha; Chen, Eugene; Ghosh, Avik W.

    2012-02-01

    Low reliable writing in spintronic devices limits their applicability in the automotive and defense industries. Coupling stochastic macromagnetic simulator with quantum transport, we show how greater reliable switching can be achieved in MRAM and multiferroic logic. Using a combination of spin-transfer torque and small applied perpendicular field in MRAM, the error rate can be considerably reduced for a given voltage pulse. In multiferroic logic, strain plays the role of the magnetic field. Information is passed along an array of nanomagnets (NM) (magnetostrictive + piezoelectric layers) through dipole coupling with neighboring NMs. A low voltage applied to the piezoelectric element causes the NM's magnetization to switch to its hard axis. Upon releasing the stress, the magnetization of the NM relaxes to the easy axis, with its final orientation determined by the dipolar coupling with the left NM, thus achieving a low power Bennett clocked computation. In the face of stagnation points along the potential energy landscape, the success rate of the straintronic switching can be controlled with by how fast the stress is removed from the NM. (Funding: DARPA, GRANDIS, NSF-NEB).

  14. A genetic bistable switch utilizing nonlinear protein degradation.

    Science.gov (United States)

    Huang, Daniel; Holtz, William J; Maharbiz, Michel M

    2012-07-09

    Bistability is a fundamental property in engineered and natural systems, conferring the ability to switch and retain states. Synthetic bistable switches in prokaryotes have mainly utilized transcriptional components in their construction. Using both transcriptional and enzymatic components, creating a hybrid system, allows for wider bistable parameter ranges in a circuit. In this paper, we demonstrate a tunable family of hybrid bistable switches in E. coli using both transcriptional components and an enzymatic component. The design contains two linked positive feedback loops. The first loop utilizes the lambda repressor, CI, and the second positive feedback loop incorporates the Lon protease found in Mesoplasma florum (mf-Lon). We experimentally tested for bistable behavior in exponential growth phase, and found that our hybrid bistable switch was able to retain its state in the absence of an input signal throughout 40 cycles of cell division. We also tested the transient behavior of our switch and found that switching speeds can be tuned by changing the expression rate of mf-Lon. To our knowledge, this work demonstrates the first use of dynamic expression of an orthogonal and heterologous protease to tune a nonlinear protein degradation circuit. The hybrid switch is potentially a more robust and tunable topology for use in prokaryotic systems.

  15. Model Reduction of Switched Systems Based on Switching Generalized Gramians

    DEFF Research Database (Denmark)

    Shaker, Hamid Reza; Wisniewski, Rafal

    2012-01-01

    In this paper, a general method for model order reduction of discrete-time switched linear systems is presented. The proposed technique uses switching generalized gramians. It is shown that several classical reduction methods can be developed into the generalized gramian framework for the model...... reduction of linear systems and for the reduction of switched systems. Discrete-time balanced reduction within a specified frequency interval is taken as an example within this framework. To avoid numerical instability and to increase the numerical efficiency, a generalized gramian-based Petrov...

  16. Node design in optical packet switched networks

    DEFF Research Database (Denmark)

    Nord, Martin

    2006-01-01

    The thesis discusses motivation, realisation and performance of the Optical Packet Switching (OPS) network paradigm. The work includes proposals for designs and methods to efficiently use both the wavelength- and time domain for contention resolution in asynchronous operation. The project has also...... adapting network performance to the different acceptable packet loss rate levels of supported applications, while improving overall bandwidth efficiency. The project has evaluated QoS differentiation methods and proposed schemes with improved efficiency, which also include jitter sensitivity as a Qo...... proposed parallel designs to overcome scalability constraints and to support migration scenarios. Furthermore, it has proposed and demonstrated optical input processing schemes for hybrids networks to simultaneously support OPS and Optical Circuit Switching. Quality of Service (QoS) differentiation enables...

  17. Multiuser hybrid switched-selection diversity systems

    KAUST Repository

    Shaqfeh, Mohammad

    2011-09-01

    A new multiuser scheduling scheme is proposed and analyzed in this paper. The proposed system combines features of conventional full-feedback selection-based diversity systems and reduced-feedback switch-based diversity systems. The new hybrid system provides flexibility in trading-off the channel information feedback overhead with the prospected multiuser diversity gains. The users are clustered into groups, and the users\\' groups are ordered into a sequence. Per-group feedback thresholds are used and optimized to maximize the system overall achievable rate. The proposed hybrid system applies switched diversity criterion to choose one of the groups, and a selection criterion to decide the user to be scheduled from the chosen group. Numerical results demonstrate that the system capacity increases as the number of users per group increases, but at the cost of more required feedback messages. © 2011 IEEE.

  18. An experimental study of VBR video over various ATM switch architectures

    Energy Technology Data Exchange (ETDEWEB)

    Tsang, R.P. [Sandia National Labs., Livermore, CA (United States); Hsieh, J.; Du, D.H.C. [Univ. of Minnesota, Minneapolis, MN (United States)

    1997-12-31

    One of the most important components of an Asynchronous Transfer Mode (ATM) network is the switch. Switch design is not a part of the ATM standards so vendors use a wide variety of techniques to build their switches. In this paper, the authors present experimental results of switching and multiplexing real-time Variable Bit Rate (VBR) video traffic (JPEG, MPEG-1, and MPEG-2) through two different ATM switch architectures. Real-time VBR traffic, such as digital video, is particularly interesting due to its high demands in terms of bandwidth, real-time delivery and processing requirements. The experiments show that the fastest switches, i.e., lowest latencies, do not necessarily perform better when transmitting VBR video. The impact of the high speed network components; characteristics, such as switch fabric architecture, buffering strategies, and higher layer transport protocols (i.e., UDP, TCP/IP), are illustrated through the experimental results.

  19. Comparative efficacy of switching to natalizumab in active multiple sclerosis

    Science.gov (United States)

    Spelman, Timothy; Kalincik, Tomas; Zhang, Annie; Pellegrini, Fabio; Wiendl, Heinz; Kappos, Ludwig; Tsvetkova, Larisa; Belachew, Shibeshih; Hyde, Robert; Verheul, Freek; Grand-Maison, Francois; Izquierdo, Guillermo; Grammond, Pierre; Duquette, Pierre; Lugaresi, Alessandra; Lechner-Scott, Jeannette; Oreja-Guevara, Celia; Hupperts, Raymond; Petersen, Thor; Barnett, Michael; Trojano, Maria; Butzkueven, Helmut

    2015-01-01

    Objective To compare treatment efficacy and persistence in patients who switched to natalizumab versus those who switched between glatiramer acetate (GA) and interferon-beta (IFNβ) after an on-treatment relapse on IFNβ or GA using propensity score matched real-world datasets. Methods Patients included were registered in MSBase or the TYSABRI Observational Program (TOP), had relapsed on IFNβ or GA within 12 months prior to switching to another therapy, and had initiated natalizumab or IFNβ/GA treatment ≤6 months after discontinuing prior therapy. Covariates were balanced across post switch treatment groups by propensity score matching at treatment initiation. Relapse, persistence, and disability measures were compared between matched treatment arms in the total population (n = 869/group) and in subgroups defined by prior treatment history (IFNβ only [n = 578/group], GA only [n = 165/group], or both IFNβ and GA [n = 176/group]). Results Compared to switching between IFNβ and GA, switching to natalizumab reduced annualized relapse rate in year one by 65–75%, the risk of first relapse by 53–82% (mean follow-up 1.7–2.2 years) and treatment discontinuation events by 48–65% (all P ≤ 0.001). In the total population, switching to natalizumab reduced the risk of confirmed disability progression by 26% (P = 0.036) and decreased the total disability burden by 1.54 EDSS-years (P < 0.0001) over the first 24 months post switch. Interpretation Using large, real-world, propensity-matched datasets we demonstrate that after a relapse on IFNβ or GA, switching to natalizumab (rather than between IFNβ and GA) led to superior outcomes for patients in all measures assessed. Results were consistent regardless of the prior treatment identity. PMID:25909083

  20. DETERMINANT OF DOWNWARD AUDITOR SWITCHING

    Directory of Open Access Journals (Sweden)

    Totok Budisantoso

    2017-12-01

    Full Text Available Abstract: Determinant of Downward Auditor Switching. This study examines the factors that influence downward auditor switching in five ASEAN countries. Fixed effect logistic regression was used as analytical method. This study found that opinion shopping occurred in ASEAN, especially in distress companies. Companies with complex businesses will retain the Big Four auditors to reduce complexity and audit costs. Audit and public committees serve as guardians of auditor quality. On the other hand, shareholders failed to maintain audit quality. It indicates that there is entrenchment effect in auditor switching.

  1. High-voltage, low-inductance gas switch

    Science.gov (United States)

    Gruner, Frederick R.; Stygar, William A.

    2016-03-22

    A low-inductance, air-insulated gas switch uses a de-enhanced annular trigger ring disposed between two opposing high voltage electrodes. The switch is DC chargeable to 200 kilovolts or more, triggerable, has low jitter (5 ns or less), has pre-fire and no-fire rates of no more than one in 10,000 shots, and has a lifetime of greater than 100,000 shots. Importantly, the switch also has a low inductance (less than 60 nH) and the ability to conduct currents with less than 100 ns rise times. The switch can be used with linear transformer drives or other pulsed-power systems.

  2. Fuel switching? Demand destruction? Gas market responses to price spikes

    International Nuclear Information System (INIS)

    Lippe, D.

    2004-01-01

    This presentation defined fuel switching and addressed the issue regarding which consumers have the capability to switch fuels. In response to short term price aberrations, consumers with fuel switching capabilities reduce their use of one fuel and increase consumption of an alternative fuel. For example, natural gas consumption by some consumers declines in response to price spikes relative to prices of alternative fuels. This presentation also addressed the issue of differentiating between fuel switching and demand destruction. It also demonstrated how to compare gas prices versus alternative fuel prices and how to determine when consumers will likely switch fuels. Price spikes have implications for long term trends in natural gas demand, supply/demand balances and prices. The power generating sector represents a particular class of gas consumers that reduce operating rates of gas fired plants and increase operating rates of other plants. Some gas consumers even shut down plants until gas prices declines and relative economies improve. Some practical considerations for fuel switching include storage tank capacity, domestic refinery production, winter heating season, and decline in working gas storage. tabs., figs

  3. Comparison of soft and hard-switching effiency in a three-level single phase 60kW dc-ac converter

    DEFF Research Database (Denmark)

    Munk-Nielsen, Stig; Teodorescu, Remus; Bech, Michael Møller

    2003-01-01

    Efficiency measurements on a three-level single-phase soft-switched converter are presented and show a slightly improved efficiency compared with the hard-switched converter for output powers higher than 25 % of rated power. The resonant converter switches are Zero Voltage Switched (ZVS......) and a simple resonant circuit is used. Increased resonant converter efficiency enables a reduction in the semiconductor size pr. watt output power or an increase the switching frequency....

  4. Solid state bistable power switch

    Science.gov (United States)

    Bartko, J.; Shulman, H.

    1970-01-01

    Tin and copper provide high current and switching time capabilities for high-current resettable fuses. They show the best performance for trip current and degree of reliability, and have low coefficients of thermal expansion.

  5. Electron collisions in gas switches

    International Nuclear Information System (INIS)

    Christophorou, L.G.

    1989-01-01

    Many technologies rely on the conduction/insulation properties of gaseous matter for their successful operation. Many others (e.g., pulsed power technologies) rely on the rapid change (switching or modulation) of the properties of gaseous matter from an insulator to a conductor and vice versa. Studies of electron collision processes in gases aided the development of pulsed power gas switches, and in this paper we shall briefly illustrate the kind of knowledge on electron collision processes which is needed to optimize the performance of such switching devices. To this end, we shall refer to three types of gas switches: spark gap closing, self-sustained diffuse discharge closing, and externally-sustained diffuse discharge opening. 24 refs., 15 figs., 2 tabs

  6. Wide Bandgap Extrinsic Photoconductive Switches

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, James S. [State Univ. of New York (SUNY), Plattsburgh, NY (United States); Univ. of California, Davis, CA (United States)

    2012-01-20

    Photoconductive semiconductor switches (PCSS) have been investigated since the late 1970s. Some devices have been developed that withstand tens of kilovolts and others that switch hundreds of amperes. However, no single device has been developed that can reliably withstand both high voltage and switch high current. Yet, photoconductive switches still hold the promise of reliable high voltage and high current operation with subnanosecond risetimes. Particularly since good quality, bulk, single crystal, wide bandgap semiconductor materials have recently become available. In this chapter we will review the basic operation of PCSS devices, status of PCSS devices and properties of the wide bandgap semiconductors 4H-SiC, 6H-SiC and 2H-GaN.

  7. A Piezoelectric Cryogenic Heat Switch

    Science.gov (United States)

    Jahromi, Amir E.; Sullivan, Dan F.

    2014-01-01

    We have measured the thermal conductance of a mechanical heat switch actuated by a piezoelectric positioner, the PZHS (PieZo electric Heat Switch), at cryogenic temperatures. The thermal conductance of the PZHS was measured between 4 K and 10 K, and on/off conductance ratios greater than 100 were achieved when the positioner applied its maximum force of 8 N. We discuss the advantages of using this system in cryogenic applications, and estimate the ultimate performance of an optimized PZHS.

  8. A Switched-Capacitor Low-Pass Filter with Dynamic Switching Bias OP Amplifiers

    Directory of Open Access Journals (Sweden)

    Hiroo Wakaumi

    2017-11-01

    Full Text Available A switched capacitor low-pass filter employing folded-cascode CMOS OP Amps with a dynamic switching bias circuit capable of processing video signals, which enables low power consumption, and operation in wide bandwidths and low power supply voltages, is proposed. In this filter, charge transfer operations through two-phase clock pulses during the on-state period of the OP Amps and a non-charge transfer operation during their remaining off-state period are separated. Through simulations, it was shown that the low-pass filter with an OP Amp switching duty ratio of 50 % is able to operate at a 14.3 MHz high-speed dynamic switching rate, allowing processing video signals, and a dissipated power of 68 % of that observed in the static operation of the OP Amps and a full charge transfer operation without separation of a cycle period. The gain below -31 dB in the frequency response, which is suitable, was obtained at over 6 MHz within a stop-band. Especially high attenuation in 5 MHz was achieved under the optimized condition of load capacitances (4 pF of OP Amps.

  9. Continuation rates, bleeding profile acceptability, and satisfaction of women using an oral contraceptive pill containing estradiol valerate and dienogest versus a progestogen-only pill after switching from an ethinylestradiol-containing pill in a real-life setting: results of the CONTENT study

    Science.gov (United States)

    Briggs, Paula; Serrani, Marco; Vogtländer, Kai; Parke, Susanne

    2016-01-01

    Background Oral contraceptives are still associated with high discontinuation rates, despite their efficacy. There is a wide choice of oral contraceptives available, and the aim of this study was to assess continuation rates, bleeding profile acceptability, and the satisfaction of women in the first year of using a contraceptive pill containing estradiol valerate and dienogest (E2V/DNG) versus a progestogen-only pill (POP) in a real-life setting after discontinuing an ethinylestradiol-containing pill. Methods and results In this prospective, noninterventional, observational study, 3,152 patients were included for the efficacy analyses (n=2,558 women in the E2V/DNG group and n=592 in the POP group (two patients fulfilled the criteria of the efficacy population, but the used product was not known). Women had been taking an ethinylestradiol-containing pill ≥3 months before deciding to switch to the E2V/DNG pill or a POP. Overall, 19.8% (n=506) of E2V/DNG users and 25.8% (n=153) of POP users discontinued their prescribed pill. The median time to discontinuation was 157.0 days and 127.5 days, respectively. Time to discontinuation due to bleeding (P<0.0001) or other reasons (P=0.022) was significantly longer in the E2V/DNG group versus the POP group. The E2V/DNG pill was also associated with shorter (48.7% vs 44.1%), lighter (54% vs 46.1%), and less painful bleeding (91.1% vs 73.7%) and greater user satisfaction (80.7% vs 64.6%) than POP use, within 3–5 months after switch. Conclusion The E2V/DNG pill was associated with higher rates of continuation, bleeding profile acceptability, and user satisfaction than POP use and may be an alternative option for women who are dissatisfied with their current pill. PMID:27695365

  10. Chromatic interocular-switch rivalry

    Science.gov (United States)

    Christiansen, Jens H.; D'Antona, Anthony D.; Shevell, Steven K.

    2017-01-01

    Interocular-switch rivalry (also known as stimulus rivalry) is a kind of binocular rivalry in which two rivalrous images are swapped between the eyes several times a second. The result is stable periods of one image and then the other, with stable intervals that span many eye swaps (Logothetis, Leopold, & Sheinberg, 1996). Previous work used this close kin of binocular rivalry with rivalrous forms. Experiments here test whether chromatic interocular-switch rivalry, in which the swapped stimuli differ in only chromaticity, results in slow alternation between two colors. Swapping equiluminant rivalrous chromaticities at 3.75 Hz resulted in slow perceptual color alternation, with one or the other color often continuously visible for two seconds or longer (during which there were 15+ eye swaps). A well-known theory for sustained percepts from interocular-switch rivalry with form is inhibitory competition between binocular neurons driven by monocular neurons with matched orientation tuning in each eye; such binocular neurons would produce a stable response when a given orientation is swapped between the eyes. A similar model can account for the percepts here from chromatic interocular-switch rivalry and is underpinned by the neurophysiological finding that color-preferring binocular neurons are driven by monocular neurons from each eye with well-matched chromatic selectivity (Peirce, Solomon, Forte, & Lennie, 2008). In contrast to chromatic interocular-switch rivalry, luminance interocular-switch rivalry with swapped stimuli that differ in only luminance did not result in slowly alternating percepts of different brightnesses. PMID:28510624

  11. Magnetic-fluid-based smart centrifugal switch

    CERN Document Server

    Bhatt, R P

    2002-01-01

    A new type of centrifugal switch, which we call 'smart centrifugal switch' is designed and developed utilizing the novel properties of magnetic fluid. No mechanical movement is involved in the sensing and switching operations of this centrifugal switch and both these operations are achieved in a smart way. The performance of the switch is studied. This switch has several important advantages over conventional centrifugal switches like smart and non-contact type operation, sparkless and hence explosion proof working and inertia-less simple structure.

  12. High-voltage, high-current, solid-state closing switch

    Energy Technology Data Exchange (ETDEWEB)

    Focia, Ronald Jeffrey

    2017-08-22

    A high-voltage, high-current, solid-state closing switch uses a field-effect transistor (e.g., a MOSFET) to trigger a high-voltage stack of thyristors. The switch can have a high hold-off voltage, high current carrying capacity, and high time-rate-of-change of current, di/dt. The fast closing switch can be used in pulsed power applications.

  13. Phenotypic switching of populations of cells in a stochastic environment

    Science.gov (United States)

    Hufton, Peter G.; Lin, Yen Ting; Galla, Tobias

    2018-02-01

    In biology phenotypic switching is a common bet-hedging strategy in the face of uncertain environmental conditions. Existing mathematical models often focus on periodically changing environments to determine the optimal phenotypic response. We focus on the case in which the environment switches randomly between discrete states. Starting from an individual-based model we derive stochastic differential equations to describe the dynamics, and obtain analytical expressions for the mean instantaneous growth rates based on the theory of piecewise-deterministic Markov processes. We show that optimal phenotypic responses are non-trivial for slow and intermediate environmental processes, and systematically compare the cases of periodic and random environments. The best response to random switching is more likely to be heterogeneity than in the case of deterministic periodic environments, net growth rates tend to be higher under stochastic environmental dynamics. The combined system of environment and population of cells can be interpreted as host-pathogen interaction, in which the host tries to choose environmental switching so as to minimise growth of the pathogen, and in which the pathogen employs a phenotypic switching optimised to increase its growth rate. We discuss the existence of Nash-like mutual best-response scenarios for such host-pathogen games.

  14. A Switch Is Not a Switch: Syntactically-Driven Bilingual Language Control

    Science.gov (United States)

    Gollan, Tamar H.; Goldrick, Matthew

    2018-01-01

    The current study investigated the possibility that language switches could be relatively automatically triggered by context. "Single-word switches," in which bilinguals switched languages on a single word in midsentence and then immediately switched back, were contrasted with more complete "whole-language switches," in which…

  15. Investigations into the use of dielectric coatings in magnetic switches

    Science.gov (United States)

    Harjes, H. C.; Sharp, D. J.; Mann, G. A.; Morgan, F. A.; Yelton, W. G.

    High reliability, high efficiency, long lifetime magnetic switches (saturable reactors) will be required in the high power pulse compression systems which are now being considered for use in several applications. One of the most critical components in a magnetic switch is its interlamina insulation. In high speed (high magnetization rate) magnetic switches, the insulation requirements are severe and the thermal management of core losses is a serious design issue. In such a switch, the interlamina voltage can approach 1000 V and, at present, dielectric films (such as Mylar, Polycarbonate, Kapton, etc.) are the only insulation options. These insulations, however, make the thermal management problem more difficult because they have low thermal conductivities and because substantial margins are required on the sides of the core. In addition, it is difficult to realize the normal holdoff strengths of thin films when they are wound with Metglas (the magnetic material of choice in most high speed switches) because the films can be degraded during the winding process by the rough Metglas surface. The results are reported of investigations into the possibility of using conformal dielectric coatings as a viable insulation option in high speed magnetic switches.

  16. Switching requirements for pulsed high-beta reactors

    International Nuclear Information System (INIS)

    Thomassen, K.I.

    1977-01-01

    Switching requirements for several high-B pulsed systems are described. These systems include linear and toroidal theta pinches, and toroidal z-pinches. The requirements are generally taken from detailed system studies. Several high-B reactor systems have been sufficiently studied to determine the switching requirements. In meeting the requirements for these devices it is likely that the technology will be useful for other systems which are at the moment less well defined. Swithcing systems for three devices are discussed here, the toroidal theta pinch, the toroidal z-pinch, and the linear theta pinch. Where possible the switching requirements are described. The toroidal theta pinch reactor (RTPR) uses 50 homopolar machines rated at 1.3 GJ each to provide its toroidal magnetic field. This energy is transferred in 30 ms at a level of 11 kV, 12.25 MA. There are 14 compression coil segments per meter of torus connected to each machine. These coil segments each have 62.5 kA, 21 kV switches in them, and the switches must act both as crowbar and interrupting switches

  17. Switching Activity Estimation of CIC Filter Integrators

    OpenAIRE

    Abbas, Muhammad; Gustafsson, Oscar

    2010-01-01

    In this work, a method for estimation of the switching activity in integrators is presented. To achieve low power, it is always necessary to develop accurate and efficient methods to estimate the switching activity. The switching activities are then used to estimate the power consumption. In our work, the switching activity is first estimated for the general purpose integrators and then it is extended for the estimation of switching activity in cascaded integrators in CIC filters. ©2010 I...

  18. Principles of broadband switching and networking

    CERN Document Server

    Liew, Soung C

    2010-01-01

    An authoritative introduction to the roles of switching and transmission in broadband integrated services networks Principles of Broadband Switching and Networking explains the design and analysis of switch architectures suitable for broadband integrated services networks, emphasizing packet-switched interconnection networks with distributed routing algorithms. The text examines the mathematical properties of these networks, rather than specific implementation technologies. Although the pedagogical explanations in this book are in the context of switches, many of the fundamenta

  19. When predictions take control: The effect of task predictions on task switching performance

    Directory of Open Access Journals (Sweden)

    Wout eDuthoo

    2012-08-01

    Full Text Available In this paper, we aimed to investigate the role of self-generated predictions in the flexible control of behaviour. Therefore, we ran a task switching experiment in which participants were asked to try to predict the upcoming task in three conditions varying in switch rate (30%, 50% and 70%. Irrespective of their predictions, the colour of the target indicated which task participants had to perform. In line with previous studies (Mayr, 2006; Monsell & Mizon, 2006, the switch cost was attenuated as the switch rate increased. Importantly, a clear task repetition bias was found in all conditions, yet the task repetition prediction rate dropped from 78% over 66% to 49% with increasing switch probability in the three conditions. Irrespective of condition, the switch cost was strongly reduced in expectation of a task alternation compared to the cost of an unexpected task alternation following repetition predictions. Hence, our data suggest that the reduction in the switch cost with increasing switch probability is caused by a diminished expectancy for the task to repeat. Taken together, this paper highlights the importance of predictions in the flexible control of behaviour, and suggests a crucial role for task repetition expectancy in the context-sensitive adjusting of task switching performance.

  20. Switching dynamics of TaOx-based threshold switching devices

    Science.gov (United States)

    Goodwill, Jonathan M.; Gala, Darshil K.; Bain, James A.; Skowronski, Marek

    2018-03-01

    Bi-stable volatile switching devices are being used as access devices in solid-state memory arrays and as the active part of compact oscillators. Such structures exhibit two stable states of resistance and switch between them at a critical value of voltage or current. A typical resistance transient under a constant amplitude voltage pulse starts with a slow decrease followed by a rapid drop and leveling off at a low steady state value. This behavior prompted the interpretation of initial delay and fast transition as due to two different processes. Here, we show that the entire transient including incubation time, transition time, and the final resistance values in TaOx-based switching can be explained by one process, namely, Joule heating with the rapid transition due to the thermal runaway. The time, which is required for the device in the conducting state to relax back to the stable high resistance one, is also consistent with the proposed mechanism.

  1. Negative correlation between enhanced crossover temperature and fluctuation-free critical current of the second switch in Bi2Sr2CaCu2O{}_{8+\\delta } intrinsic Josephson junction

    Science.gov (United States)

    Nomura, Y.; Okamoto, R.; Kakeya, I.

    2017-10-01

    We have investigated the switching dynamics of the first and second switches in intrinsic Josephson junctions (IJJs) of Bi2Sr2CaCu2O{}8+δ with different maximum Josephson current density J c to reveal the doping evolution of interaction between IJJs. For the second switch, the crossover temperature between temperature-independent switching similar to quantum tunneling and thermally activated switching {T}2{nd}* is remarkably higher than that for the first switch. Moreover, {T}2{nd}* slightly decreases with increasing J c, which violates the conventional relation between the crossover temperature and the critical current density. These features can be explained not by a change in the Josephson coupling energy but by a change in the charging energy of the Josephson junction. We argue that the capacitive coupling model explains the increase in the fluctuation in the quantum regime of the second switch and the anti-correlation between {T}2{nd}* and J c. Furthermore, inductive coupling does not contribute to these peculiar phenomena in the switching dynamics of stacked IJJs.

  2. IGBT: a solid state switch

    International Nuclear Information System (INIS)

    Chatroux, D.; Maury, J.; Hennevin, B.

    1993-01-01

    A Copper Vapour Laser Power Supply has been designed using a solid state switch consisting in eighteen Isolated Gate Bipolar Transistors (IGBT), -1200 volts, 400 Amps, each-in parallel. This paper presents the Isolated Gate Bipolar Transistor (IGBTs) replaced in the Power Electronic components evolution, and describes the IGBT conduction mechanism, presents the parallel association of IGBTs, and studies the application of these components to a Copper Vapour Laser Power Supply. The storage capacitor voltage is 820 volts, the peak current of the solid state switch is 17.000 Amps. The switch is connected on the primary of a step-up transformer, followed by a magnetic modulator. The reset of the magnetic modulator is provided by part of the laser reflected energy with a patented circuit. The charging circuit is a resonant circuit with a charge controlled by an IGBT switch. When the switch is open, the inductance energy is free-wheeled by an additional winding and does not extend the charging phase of the storage capacitor. The design allows the storage capacitor voltage to be very well regulated. This circuit is also patented. The electric pulse in the laser has 30.000 Volt peak voltage, 2000 Amp peak current, and is 200 nanoseconds long, for a 200 Watt optical power Copper Vapour Laser

  3. Magnetic particle separation using controllable magnetic force switches

    International Nuclear Information System (INIS)

    Wei Zunghang; Lee, C.-P.; Lai, M.-F.

    2010-01-01

    Magnetic particle separation is very important in biomedical applications. In this study, a magnetic particle microseparator is proposed that uses micro magnets to produce open/closed magnetic flux for switching on/off the separation. When all magnets are magnetized in the same direction, the magnetic force switch for separation is on; almost all magnetic particles are trapped in the channel side walls and the separation rate can reach 95%. When the magnetization directions of adjacent magnets are opposite, the magnetic force switch for separation is off, and most magnetic particles pass through the microchannel without being trapped. For the separation of multi-sized magnetic particles, the proposed microseparator is numerically demonstrated to have high separation rate.

  4. Predictors of switching from mania to depression in a large observational study across Europe (EMBLEM).

    Science.gov (United States)

    Vieta, Eduard; Angst, Jules; Reed, Catherine; Bertsch, Jordan; Haro, Josep Maria

    2009-11-01

    The risk of switching from mania to depression in bipolar disorder has been poorly studied. Large observational studies may be useful in identifying variables that predict switch to depression after mania and provide data on medication use and outcomes in "real world" patients. EMBLEM (European Mania in Bipolar Longitudinal Evaluation of Medication) is a 2-year, prospective, observational study of patients with a manic/mixed episode. Symptom severity measures included Clinical Global Impression-Bipolar Disorder scale (CGI-BP), Young Mania Rating Scale (YMRS) and 5-item Hamilton Depression Rating Scale. Switching was defined using CGI-BP mania and depression such that patients changed from manic and not depressed to depressed but not manic over two consecutive observations within the first 12 weeks of follow-up. Cox proportional hazards models identified baseline variables independently associated with switch to depression. Of 2390 patients who participated in the maintenance phase (i.e. up to 24 months), 120 (5.0%) switched to depression within the first 12 weeks. Factors associated with greater switching to depression include previous depressive episodes, substance abuse, greater CGI-BP overall severity and benzodiazepine use. Factors associated with lower switching rates were greater CGI-BP depression, lower YMRS severity and atypical antipsychotic use. The definition of switching biased against patients with mixed episodes being likely to switch. Strictly defined, switch to depression from mania occurs in a small proportion of bipolar patients. Clinical history, illness severity, co-morbidities and treatment patterns are associated with switching to depression. Atypical antipsychotics may protect against switch to depression.

  5. Portable Userspace Virtual Filesystem Switch

    Directory of Open Access Journals (Sweden)

    Łukasz Faber

    2013-01-01

    Full Text Available Multiple different filesystems — including disk-based, network, distributed, abstract — arean integral part of every operating system. They are usually written as kernel modules and abstracted to the user via a virtual filesystem switch. In this paper we analyse the feasibility of reimplementing the virtual filesystem switch as a userspace daemon and applicability of this approach in real-life usage. Such reimplementation will require a way to virtualise processes behaviour related to filesystem operations. The problem is non-trivial, as we assume limited capabilities of the VFS switch implemented in userspace. We present a layered architecture comprising of a monitoring process, the VFS abstraction and real filesystem implementations. All working in userspace. Then, we evaluate this solution in four areas: portability, feasibility, usability and performance. Our results demonstrate possible gains in using the userspace-based approach with monolithic kernels, but also underline problems that are encountered in this approach.

  6. Buffer allocation in an ATM switch with output buffer and speed constraints

    Science.gov (United States)

    Gupta, Anil K.; Georganas, N. D.

    A synchronous nonblocking N times N switch for asynchronous transfer mode (ATM) networks or high speed packet switching networks transporting fixed length packets called cells is considered. Such a switch with output queuing achieves the optimal performance, however it requires the switch fabric to work at the speed of N. In practice the switch may operate L times faster than the input/output trunk. It is assumed that queues at each output port have a limited buffer space and whenever an output queue is full, the back-pressure is applied and the packets are retained at the head of the input queues. The upper bound on the packet loss probability at the input queues in such a switch are computed. To achieve a given packet loss rate, the switch with L equals 2 requires almost the same amount of input and output buffers as with L equals 4 up to 70 percent input load, but as the load increases beyond 70 percent the switch with L equals 4 would require more output buffers and less input buffers in comparison with a switch operating at L equals 2. The performance of a switch with L equals 3 is very similar to that for L equals 4 and is not considered.

  7. All-fiber polarization switch

    Science.gov (United States)

    Knape, Harald; Margulis, Walter

    2007-03-01

    We report an all-fiber polarization switch made out of silica-based microstructured fiber suitable for Q-switching all-fiber lasers. Nanosecond high-voltage pulses are used to heat and expand an internal electrode to cause λ/2-polarization rotation in less than 10 ns for 1.5 μm light. The 10 cm long component has an experimentally measured optical insertion loss of 0.2 dB and a 0-10 kHz repetition frequency capacity and has been durability tested for more than 109 pulses.

  8. Industry switching in developing countries

    DEFF Research Database (Denmark)

    Newman, Carol; Rand, John; Tarp, Finn

    2013-01-01

    Firm turnover (i.e., firm entry and exit) is a well-recognized source of sector-level productivity growth. In contrast, the role and importance of firms that switch activities from one sector to another is not well understood. Firm switchers are likely to be unique, differing from both newly...... and behavior than do entry and exit firms. Switchers tend to be labor intensive and to seek competitive opportunities in labor-intensive sectors in response to changes in market environments. Moreover, resource reallocation resulting from switching forms an important component of productivity growth. The topic...

  9. CMOS integrated switching power converters

    CERN Document Server

    Villar-Pique, Gerard

    2011-01-01

    This book describes the structured design and optimization of efficient, energy processing integrated circuits. The approach is multidisciplinary, covering the monolithic integration of IC design techniques, power electronics and control theory. In particular, this book enables readers to conceive, synthesize, design and implement integrated circuits with high-density high-efficiency on-chip switching power regulators. Topics covered encompass the structured design of the on-chip power supply, efficiency optimization, IC-compatible power inductors and capacitors, power MOSFET switches and effi

  10. Studies on nonvolatile resistance memory switching in ZnO thin films

    Indian Academy of Sciences (India)

    Administrator

    the material during switching between the low and high resistance states (Choi et al 2005). The advantages of. RRAM systems over the other competing modes are the lower operating voltages and power consumption, faster switching rate, smaller and simpler bit cell structure and higher packing density (Chang et al 2008).

  11. Wavelength conversion in optical packet switching

    DEFF Research Database (Denmark)

    Danielsen, Søren Lykke; Hansen, Peter Bukhave; Stubkjær, Kristian

    1998-01-01

    A detailed traffic analysis of optical packet switch design is performed. Special consideration is given to the complexity of the optical buffering and the overall switch block structure is considered in general. Wavelength converters are shown to improve the traffic performance of the switch...... blocks for both random and bursty traffic. Furthermore, the traffic performance of switch blocks with add-drop switches has been assessed in a Shufflenetwork showing the advantage of having converters at the inlets. Finally, the aspect of synchronization is discussed through a proposal to operate...... the packet switch block asynchronously, i.e. without packet alignment at the input...

  12. Switching in electrical transmission and distribution systems

    CERN Document Server

    Smeets, René; Kapetanovic, Mirsad; Peelo, David F; Janssen, Anton

    2014-01-01

    Switching in Electrical Transmission and Distribution Systems presents the issues and technological solutions associated with switching in power systems, from medium to ultra-high voltage. The book systematically discusses the electrical aspects of switching, details the way load and fault currents are interrupted, the impact of fault currents, and compares switching equipment in particular circuit-breakers. The authors also explain all examples of practical switching phenomena by examining real measurements from switching tests. Other highlights include: up to date commentary on new develo

  13. Switching dynamics in InP photonic-crystal nanocavity

    DEFF Research Database (Denmark)

    Yu, Yi; Palushani, Evarist; Heuck, Mikkel

    2016-01-01

    In this paper, we presented switching dynamic investigations on an InP photonic-crystal (PhC) nanocavity structure using homodyne pump-probe measurements. The measurements were compared with simulations based on temporal nonlinear coupled mode theory and carrier rate equations for the dynamics of...

  14. A new FET-bipolar combinational power semiconductor switch

    Science.gov (United States)

    Chen, D. Y.; Chandrasekaran, S.; Chin, S. A.

    1984-01-01

    A novel FET-BJT combinational transistor configuration is proposed and demonstrated using discrete devices. This new transistor features fast switching, very simple drive requirement, elimination of reverse bias second breakdown, and good utilization of semiconductor chip area. Initial results indicate that power hybrid construction of the device is essential to enhance the current rating of the device.

  15. Soliton switching in directional couplers

    NARCIS (Netherlands)

    Valkering, T.P.; Hoekstra, Hugo; de Boer, Pieter-Tjerk

    1999-01-01

    The mechanism of pulse switching is investigated analytically and numerically for a family of initial conditions with a solitonlike pulse in one channel and no signal on the other channel of the coupler. This investigation is performed directly in the coupled nonlinear Schroedinger equations that

  16. Intrinsic nanofilamentation in resistive switching

    KAUST Repository

    Wu, Xing

    2013-03-15

    Resistive switching materials are promising candidates for nonvolatile data storage and reconfiguration of electronic applications. Intensive studies have been carried out on sandwiched metal-insulator-metal structures to achieve high density on-chip circuitry and non-volatile memory storage. Here, we provide insight into the mechanisms that govern highly reproducible controlled resistive switching via a nanofilament by using an asymmetric metal-insulator-semiconductor structure. In-situ transmission electron microscopy is used to study in real-time the physical structure and analyze the chemical composition of the nanofilament dynamically during resistive switching. Electrical stressing using an external voltage was applied by a tungsten tip to the nanosized devices having hafnium oxide (HfO2) as the insulator layer. The formation and rupture of the nanofilaments result in up to three orders of magnitude change in the current flowing through the dielectric during the switching event. Oxygen vacancies and metal atoms from the anode constitute the chemistry of the nanofilament.

  17. Switching Costs in Accounting Services

    Directory of Open Access Journals (Sweden)

    Fatih Koç

    2015-06-01

    Full Text Available Switching cost is defined as possible costs that customers may encounter when they want to change the firm they buy service, and an important subject in terms of accounting services. Particularly, small business entrepreneurs’ not having knowledge about accounting procedures, and sharing private information with accounting firms make switching costs more important for accounting services. Thus, the aim of this study is to investigate the concept of switching costs (relational cost, procedural cost and financial cost, its determinants (perceived service quality, service importance, and service failures, and consequences (re-purchasing, and recommen ding to others. Theresearch was conducted on small business entrepreneurs in down-town of Balıkesir in Turkey. Total 405 small business entrepreneur owners were interviewed. According to results of the study, perceived service quality positively affects all dimensions of switching costs, significance of service positively affects procedural and relational costs, and service failures negatively affect procedural and relational costs. The results showed that while procedural and relational costs positively affect re-purchasing and recommending to others variables, financial cost did not have any effect on these variables.

  18. Nanoscale organic ferroelectric resistive switches

    NARCIS (Netherlands)

    Khikhlovskyi, V.; Wang, R.; Breemen, A.J.J.M. van; Gelinck, G.H.; Janssen, R.A.J.; Kemerink, M.

    2014-01-01

    Organic ferroelectric resistive switches function by grace of nanoscale phase separation in a blend of a semiconducting and a ferroelectric polymer that is sandwiched between metallic electrodes. In this work, various scanning probe techniques are combined with numerical modeling to unravel their

  19. Switching processes in financial markets.

    Science.gov (United States)

    Preis, Tobias; Schneider, Johannes J; Stanley, H Eugene

    2011-05-10

    For an intriguing variety of switching processes in nature, the underlying complex system abruptly changes from one state to another in a highly discontinuous fashion. Financial market fluctuations are characterized by many abrupt switchings creating upward trends and downward trends, on time scales ranging from macroscopic trends persisting for hundreds of days to microscopic trends persisting for a few minutes. The question arises whether these ubiquitous switching processes have quantifiable features independent of the time horizon studied. We find striking scale-free behavior of the transaction volume after each switching. Our findings can be interpreted as being consistent with time-dependent collective behavior of financial market participants. We test the possible universality of our result by performing a parallel analysis of fluctuations in time intervals between transactions. We suggest that the well known catastrophic bubbles that occur on large time scales--such as the most recent financial crisis--may not be outliers but single dramatic representatives caused by the formation of increasing and decreasing trends on time scales varying over nine orders of magnitude from very large down to very small.

  20. Wide Bandgap Extrinsic Photoconductive Switches

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, James S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-07-03

    Semi-insulating Gallium Nitride, 4H and 6H Silicon Carbide are attractive materials for compact, high voltage, extrinsic, photoconductive switches due to their wide bandgap, high dark resistance, high critical electric field strength and high electron saturation velocity. These wide bandgap semiconductors are made semi-insulating by the addition of vanadium (4H and 6HSiC) and iron (2H-GaN) impurities that form deep acceptors. These deep acceptors trap electrons donated from shallow donor impurities. The electrons can be optically excited from these deep acceptor levels into the conduction band to transition the wide bandgap semiconductor materials from a semi-insulating to a conducting state. Extrinsic photoconductive switches with opposing electrodes have been constructed using vanadium compensated 6H-SiC and iron compensated 2H-GaN. These extrinsic photoconductive switches were tested at high voltage and high power to determine if they could be successfully used as the closing switch in compact medical accelerators.

  1. Androgenic switch in barley microspores

    NARCIS (Netherlands)

    de Faria Maraschin, Simone

    2005-01-01

    Barley androgenesis represents an attractive system to study stress-induced cell differentiation and is a valuable tool for efficient plant breeding. The switch from the pollen developmental pathway towards an androgenic route involves several well-described morphological changes. However, little is

  2. Microstrip PIN diode microwave switch

    OpenAIRE

    Usanov, Dmitry A.; Skripal, A. V.; Kulikov, M. Yu.

    2011-01-01

    A possibility of creating narrow-band electrically controlled microwave breakers and switches with enhanced attenuation level in the blocking mode has been considered. The specified devices are based on the structure containing a short-circuited microstrip link with connected capacitor and the loop coupler, in the center of which is located a PIN diode.

  3. The Atlas load protection switch

    CERN Document Server

    Davis, H A; Dorr, G; Martínez, M; Gribble, R F; Nielsen, K E; Pierce, D; Parsons, W M

    1999-01-01

    Atlas is a high-energy pulsed-power facility under development to study materials properties and hydrodynamics experiments under extreme conditions. Atlas will implode heavy liner loads (m~45 gm) with a peak current of 27-32 MA delivered in 4 mu s, and is energized by 96, 240 kV Marx generators storing a total of 23 MJ. A key design requirement for Atlas is obtaining useful data for 95601130f all loads installed on the machine. Materials response calculations show current from a prefire can damage the load requiring expensive and time consuming replacement. Therefore, we have incorporated a set of fast-acting mechanical switches in the Atlas design to reduce the probability of a prefire damaging the load. These switches, referred to as the load protection switches, short the load through a very low inductance path during system charge. Once the capacitors have reached full charge, the switches open on a time scale short compared to the bank charge time, allowing current to flow to the load when the trigger pu...

  4. Continuation rates, bleeding profile acceptability, and satisfaction of women using an oral contraceptive pill containing estradiol valerate and dienogest versus a progestogen-only pill after switching from an ethinylestradiol-containing pill in a real-life setting: results of the CONTENT study

    Directory of Open Access Journals (Sweden)

    Briggs P

    2016-09-01

    Full Text Available Paula Briggs,1 Marco Serrani,2 Kai Vogtländer,3 Susanne Parke4 1Sexual and Reproductive Health, Southport and Ormskirk Hospital NHS Trust, Merseyside, UK; 2Global Medical Affairs Women’s HealthCare, Bayer Pharma AG, Berlin, 3Global Integrated Analysis & Life Cycle Management Statistics, Bayer Pharma AG, Wuppertal, 4Global Clinical Development Women’s HealthCare, Bayer Pharma AG, Berlin, Germany Background: Oral contraceptives are still associated with high discontinuation rates, despite their efficacy. There is a wide choice of oral contraceptives available, and the aim of this study was to assess continuation rates, bleeding profile acceptability, and the satisfaction of women in the first year of using a contraceptive pill containing estradiol valerate and dienogest (E2V/DNG versus a progestogen-only pill (POP in a real-life setting after discontinuing an ethinylestradiol-containing pill.Methods and results: In this prospective, noninterventional, observational study, 3,152 patients were included for the efficacy analyses (n=2,558 women in the E2V/DNG group and n=592 in the POP group (two patients fulfilled the criteria of the efficacy population, but the used product was not known. Women had been taking an ethinylestradiol-containing pill ≥3 months before deciding to switch to the E2V/DNG pill or a POP. Overall, 19.8% (n=506 of E2V/DNG users and 25.8% (n=153 of POP users discontinued their prescribed pill. The median time to discontinuation was 157.0 days and 127.5 days, respectively. Time to discontinuation due to bleeding (P<0.0001 or other reasons (P=0.022 was significantly longer in the E2V/DNG group versus the POP group. The E2V/DNG pill was also associated with shorter (48.7% vs 44.1%, lighter (54% vs 46.1%, and less painful bleeding (91.1% vs 73.7% and greater user satisfaction (80.7% vs 64.6% than POP use, within 3–5 months after switch.Conclusion: The E2V/DNG pill was associated with higher rates of continuation

  5. Switch-connected HyperX network

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Dong; Heidelberger, Philip

    2018-02-13

    A network system includes a plurality of sub-network planes and global switches. The sub-network planes have a same network topology as each other. Each of the sub-network planes includes edge switches. Each of the edge switches has N ports. Each of the global switches is configured to connect a group of edge switches at a same location in the sub-network planes. In each of the sub-network planes, some of the N ports of each of the edge switches are connected to end nodes, and others of the N ports are connected to other edge switches in the same sub-network plane, other of the N ports are connected to at least one of the global switches.

  6. Spectrally efficient switched transmit diversity for spectrum sharing systems

    KAUST Repository

    Bouida, Zied

    2011-09-01

    Under the scenario of an underlay cognitive radio network, we propose in this paper an adaptive scheme using switched transmit diversity and adaptive modulation in order to increase the spectral efficiency of the secondary link. The proposed bandwidth efficient scheme (BES) uses the scan and wait (SWC) combining technique where a transmission occurs only when a branch with an acceptable performance is found, otherwise data is buffered. In our scheme, the modulation constellation size and the used transmit branch are determined to achieve the highest spectral efficiency given the fading channel conditions, the required error rate performance, and a peak interference constraint to the primary receiver. Selected numerical examples show that the BES scheme increases the capacity of the secondary link when compared to an existing switching efficient scheme (SES). This spectral efficiency comes at the expense of an increased average number of switched branches and thus an increased average delay. © 2011 IEEE.

  7. Selective and genetic constraints on pneumococcal serotype switching.

    Directory of Open Access Journals (Sweden)

    Nicholas J Croucher

    2015-03-01

    Full Text Available Streptococcus pneumoniae isolates typically express one of over 90 immunologically distinguishable polysaccharide capsules (serotypes, which can be classified into "serogroups" based on cross-reactivity with certain antibodies. Pneumococci can alter their serotype through recombinations affecting the capsule polysaccharide synthesis (cps locus. Twenty such "serotype switching" events were fully characterised using a collection of 616 whole genome sequences from systematic surveys of pneumococcal carriage. Eleven of these were within-serogroup switches, representing a highly significant (p < 0.0001 enrichment based on the observed serotype distribution. Whereas the recombinations resulting in between-serogroup switches all spanned the entire cps locus, some of those that caused within-serogroup switches did not. However, higher rates of within-serogroup switching could not be fully explained by either more frequent, shorter recombinations, nor by genetic linkage to genes involved in β-lactam resistance. This suggested the observed pattern was a consequence of selection for preserving serogroup. Phenotyping of strains constructed to express different serotypes in common genetic backgrounds was used to test whether genotypes were physiologically adapted to particular serogroups. These data were consistent with epistatic interactions between the cps locus and the rest of the genome that were specific to serotype, but not serogroup, meaning they were unlikely to account for the observed distribution of capsule types. Exclusion of these genetic and physiological hypotheses suggested future work should focus on alternative mechanisms, such as host immunity spanning multiple serotypes within the same serogroup, which might explain the observed pattern.

  8. Smokeless tobacco brand switching: a means to reduce toxicant exposure?

    Science.gov (United States)

    Hatsukami, D K; Ebbert, J O; Anderson, A; Lin, H; Le, C; Hecht, S S

    2007-03-16

    The purpose of this study was to examine the effects of smokeless tobacco (ST) brand switching on biomarkers of ST exposure and on ST use. Subjects seeking treatment to reduce their use were randomized to ST brand switching with controlled ST topography, brand switching with ad libitum ST use, or a waitlist control with subsequent randomization to one of these two conditions. The waitlist control group was included to assess whether changes were a consequence of time effect. During the intervention, Copenhagen or Kodiak ST users were asked to switch to products that were sequentially lower in nicotine content: Skoal Long Cut Straight or Wintergreen for 4 weeks and then Skoal Bandits for the subsequent 4 weeks. Measures were obtained during the course of treatment and at 12-week follow-up. Significant reductions in total urinary cotinine and 4-(methylnitrosamino)-L-(3-pyridyl)-L-butanol (NNAL) plus its glucuronides (total NNAL) were observed with no significant differences between the controlled topography and ad libitum conditions. Significant reductions were also observed in the amount and duration of dips with a significant intervention effect for durational measures. At 12 weeks, the 7-day biochemically-verified tobacco abstinent rate was 26% in the ad libitum group. ST brand switching may be a feasible alternative intervention for ST users interested in quitting but unwilling to stop ST use completely.

  9. Design of DC-contact RF MEMS switch with temperature stability

    Directory of Open Access Journals (Sweden)

    Junfeng Sun

    2015-04-01

    Full Text Available In order to improve the temperature stability of DC-contact RF MEMS switch, a thermal buckle-beam structure is implemented. The stability of the switch pull-in voltage versus temperature is not only improved, but also the impact of stress and stress gradient on the drive voltage is suppressed. Test results show that the switch pull-in voltage is less sensitive to temperature between -20 °C and 100 °C. The variable rate of pull-in voltage to temperature is about -120 mV/°C. The RF performance of the switch is stable, and the isolation is almost independent of temperature. After being annealed at 280 °C for 12 hours, our switch samples, which are suitable for packaging, have less than 1.5% change in the rate of pull-in voltage.

  10. Genes contribute to the switching dynamics of bistable perception.

    Science.gov (United States)

    Shannon, Robert W; Patrick, Christopher J; Jiang, Yi; Bernat, Edward; He, Sheng

    2011-03-09

    Ordinarily, the visual system provides an unambiguous representation of the world. However, at times alternative plausible interpretations of a given stimulus arise, resulting in a dynamic perceptual alternation of the differing interpretations, commonly referred to as bistable or rivalrous perception. Recent research suggests that common neural mechanisms may be involved in the dynamics of very different types of bistable phenomena. Further, evidence has emerged that genetic factors may be involved in determining the rate of switch for at least one form of bistable perception, known as binocular rivalry. The current study evaluated whether genetic factors contribute to the switching dynamics for distinctly different variants of bistable perception in the same participant sample. Switching rates were recorded for MZ and DZ twin participants in two different bistable perception tasks, binocular rivalry and the Necker Cube. Strong concordance in switching rates across both tasks was evident for MZ but not DZ twins, indicating that genetic factors indeed contribute to the dynamics of multiple forms of bistable perception.

  11. 49 CFR 236.822 - Switch, spring.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Switch, spring. 236.822 Section 236.822... Switch, spring. A switch equipped with a spring device which forces the points to their original position after being trailed through and holds them under spring compression. ...

  12. Bootstrapped Low-Voltage Analog Switches

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    1999-01-01

    Novel low-voltage constant-impedance analog switch circuits are proposed. The switch element is a single MOSFET, and constant-impedance operation is obtained using simple circuits to adjust the gate and bulk voltages relative to the switched signal. Low-voltage (1-volt) operation is made feasible...

  13. Caffeine improves anticipatory processes in task switching

    NARCIS (Netherlands)

    Tieges, Zoe; Snel, Jan; Kok, Albert; Wijnen, Jasper G.; Lorist, Monicque M.; Ridderinkhof, K. Richard

    We studied the effects of moderate amounts of caffeine on task switching and task maintenance using mixed-task (AABB) blocks, in which participants alternated predictably between two tasks, and single-task (AAAA, BBBB) blocks. Switch costs refer to longer reaction times (RT) on task switch trials

  14. Switching antidepressants | Outhoff | South African Family Practice

    African Journals Online (AJOL)

    ... worsening depression or unpleasant discontinuation reactions. Switching strategies to minimise these risks include immediate switching, cross-tapering or incorporating a washout period. Immediate switching is generally possible when substituting a selective serotonin reuptake inhibitor or a serotonin and noradrenaline ...

  15. Degree of Conversational Code-Switching Enhances Verbal Task Switching in Cantonese-English Bilinguals

    Science.gov (United States)

    Yim, Odilia; Bialystok, Ellen

    2012-01-01

    The study examined individual differences in code-switching to determine the relationship between code-switching frequency and performance in verbal and non-verbal task switching. Seventy-eight Cantonese-English bilinguals completed a semi-structured conversation to quantify natural code-switching, a verbal fluency task requiring language…

  16. Electronic logic to enhance switch reliability in detecting openings and closures of redundant switches

    Science.gov (United States)

    Cooper, James A.

    1986-01-01

    A logic circuit is used to enhance redundant switch reliability. Two or more switches are monitored for logical high or low output. The output for the logic circuit produces a redundant and failsafe representation of the switch outputs. When both switch outputs are high, the output is high. Similarly, when both switch outputs are low, the logic circuit's output is low. When the output states of the two switches do not agree, the circuit resolves the conflict by memorizing the last output state which both switches were simultaneously in and produces the logical complement of this output state. Thus, the logic circuit of the present invention allows the redundant switches to be treated as if they were in parallel when the switches are open and as if they were in series when the switches are closed. A failsafe system having maximum reliability is thereby produced.

  17. Erasing the Epigenetic Memory and Beginning to Switch—The Onset of Antigenic Switching of var Genes in Plasmodium falciparum

    Science.gov (United States)

    Fastman, Yair; Noble, Robert; Recker, Mario; Dzikowski, Ron

    2012-01-01

    Antigenic variation in Plasmodium falciparum is regulated by transcriptional switches among members of the var gene family, each expressed in a mutually exclusive manner and encoding a different variant of the surface antigens collectively named PfEMP1. Antigenic switching starts when the first merozoites egress from the liver and begin their asexual proliferation within red blood cells. By erasing the epigenetic memory we created parasites with no var background, similar to merozoites that egress from the liver where no var gene is expressed. Creating a null-var background enabled us to investigate the onset of antigenic switches at the early phase of infection. At the onset of switching, var transcription pattern is heterogeneous with numerous genes transcribed at low levels including upsA vars, a subtype that was implicated in severe malaria, which are rarely activated in growing cultures. Analysis of subsequent in vitro switches shows that the probability of a gene to turn on or off is not associated with its chromosomal position or promoter type per se but on intrinsic properties of each gene. We concluded that var switching is determined by gene specific associated switch rates rather than general promoter type or locus associated switch rates. In addition, we show that fine tuned reduction in var transcription increases their switch rate, indicating that transcriptional perturbation can alter antigenic switching. PMID:22461905

  18. Shape memory thermal conduction switch

    Science.gov (United States)

    Vaidyanathan, Rajan (Inventor); Krishnan, Vinu (Inventor); Notardonato, William U. (Inventor)

    2010-01-01

    A thermal conduction switch includes a thermally-conductive first member having a first thermal contacting structure for securing the first member as a stationary member to a thermally regulated body or a body requiring thermal regulation. A movable thermally-conductive second member has a second thermal contacting surface. A thermally conductive coupler is interposed between the first member and the second member for thermally coupling the first member to the second member. At least one control spring is coupled between the first member and the second member. The control spring includes a NiTiFe comprising shape memory (SM) material that provides a phase change temperature <273 K, a transformation range <40 K, and a hysteresis of <10 K. A bias spring is between the first member and the second member. At the phase change the switch provides a distance change (displacement) between first and second member by at least 1 mm, such as 2 to 4 mm.

  19. Switch for Good Community Program

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, Tabitha [Balfour Beatty Military Housing Management LLC, Newtown Square, PA (United States); Amran, Martha [WattzOn, Inc., Mountain View, CA (United States)

    2013-11-19

    Switch4Good is an energy-savings program that helps residents reduce consumption from behavior changes; it was co-developed by Balfour Beatty Military Housing Management (BB) and WattzOn in Phase I of this grant. The program was offered at 11 Navy bases. Three customer engagement strategies were evaluated, and it was found that Digital Nudges (a combination of monthly consumption statements with frequent messaging via text or email) was most cost-effective. The program was delivered on-time and on-budget, and its success is based on the teamwork of local BB staff and the WattzOn team. The following graphic shows Switch4Good “by the numbers”, e.g. the scale of operations achieved during Phase I.

  20. Negation switching invariant signed graphs

    Directory of Open Access Journals (Sweden)

    Deepa Sinha

    2014-04-01

    Full Text Available A signed graph (or, $sigraph$ in short is a graph G in which each edge x carries a value $\\sigma(x \\in \\{-, +\\}$ called its sign. Given a sigraph S, the negation $\\eta(S$ of the sigraph S is a sigraph obtained from S by reversing the sign of every edge of S. Two sigraphs $S_{1}$ and $S_{2}$ on the same underlying graph are switching equivalent if it is possible to assign signs `+' (`plus' or `-' (`minus' to vertices of $S_{1}$ such that by reversing the sign of each of its edges that has received opposite signs at its ends, one obtains $S_{2}$. In this paper, we characterize sigraphs which are negation switching invariant and also see for what sigraphs, S and $\\eta (S$ are signed isomorphic.

  1. Large aperture optical switching devices

    International Nuclear Information System (INIS)

    Goldhar, J.; Henesian, M.A.

    1983-01-01

    We have developed a new approach to constructing large aperture optical switches for next generation inertial confinement fusion lasers. A transparent plasma electrode formed in low pressure ionized gas acts as a conductive coating to allow the uniform charging of the optical faces of an electro-optic material. In this manner large electric fields can be applied longitudinally to large aperture, high aspect ratio Pockels cells. We propose a four-electrode geometry to create the necessary high conductivity plasma sheets, and have demonstrated fast (less than 10 nsec) switching in a 5x5 cm aperture KD*P Pockels cell with such a design. Detaid modelling of Pockels cell performance with plasma electrodes has been carried out for 15 and 30 cm aperture designs

  2. Resistive Switching Assisted by Noise

    OpenAIRE

    Patterson, G. A.; Fierens, P. I.; Grosz, D. F.

    2013-01-01

    We extend results by Stotland and Di Ventra on the phenomenon of resistive switching aided by noise. We further the analysis of the mechanism underlying the beneficial role of noise and study the EPIR (Electrical Pulse Induced Resistance) ratio dependence with noise power. In the case of internal noise we find an optimal range where the EPIR ratio is both maximized and independent of the preceding resistive state. However, when external noise is considered no beneficial effect is observed.

  3. The prevalence of brand switching among adult smokers in the USA, 2006-2011: findings from the ITC US surveys.

    Science.gov (United States)

    Cornelius, Monica E; Cummings, K Michael; Fong, Geoffrey T; Hyland, Andrew; Driezen, Pete; Chaloupka, Frank J; Hammond, David; O'Connor, Richard J; Bansal-Travers, Maansi

    2015-11-01

    Recent studies have suggested that about 1 in 5 smokers report switching brands per year. However, these studies only report switching between brands. The current study estimated the rates of switching both within and between brand families and examining factors associated with brand and brand style switching. Data for this analysis are from the International Tobacco Control 2006-2011 US adult smoker cohort survey waves 5-8 (N=3248). A switch between brands was defined as reporting two different cigarette brand names for two successive waves, while switching within brand was defined as reporting the same brand name, but a different brand style. Repeated measures regression was used to determine factors associated with both switch types. A total of 1475 participants reported at least two successive waves of data with complete information on brand name and style. Overall switching increased from 44.9% in 2007-2008 to 58.4% in 2010-2011. Switching between brand names increased from 16% to 29%, while switches within the same brand name to a different style ranged from 29% to 33%. Between-brand switching was associated with younger age, lower income, non-white racial group and use of a discount brand, whereas, within-brand switching was associated with younger age and the use of a premium brand cigarette. Nearly half of smokers in the USA switched their cigarette brand or brand style within a year. Switching between brands may be more price motivated, while switching within brands may be motivated by price and other brand characteristics such as product length. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  4. Physical limitations to efficient high-speed spin-torque switching in magnetic tunnel junctions

    Science.gov (United States)

    Heindl, R.; Rippard, W. H.; Russek, S. E.; Kos, A. B.

    2011-02-01

    We have investigated the physical limitations to efficient high-speed spin-torque switching by means of write error rates both experimentally as well as through macrospin simulations. The spin-torque-induced write operations were performed on in-plane MgO magnetic tunnel junctions. The write error rates were determined from up to 106 switching events as a function of pulse amplitude and duration (5 to 100 ns) for devices with different thermal stability factors. Both experiments and simulations show qualitatively similar results. In particular, the write error rates as a function of pulse voltage amplitude increase at higher rates for pulse durations below ≈50 ns. Simulations show that the write error rates can be reduced only to some extent by the use of materials with perpendicular anisotropy and reduced damping, whereas noncollinear orientation of the spin current polarization and the magnetic easy axis increases the write error rates. The cause for the write error rates is related to the underlying physics of spin-torque switching and the occurrence of the stagnation point on the magnetization switching trajectory where the spin-torque disappears and the device loses the energy needed to switch. The stagnation point can be accessed either during the initial magnetization distribution or by thermal diffusion during the switching process.

  5. Molecular wires, switches and memories

    Science.gov (United States)

    Chen, Jia

    Molecular electronics, an emerging field, makes it possible to build individual molecules capable of performing functions identical or analogous to present- day conductors, switches, or memories. These individual molecules, with a nano-meter scale characteristic length, can be designed and chemically synthesized with specific atoms, geometries and charge distribution. This thesis focuses on the design, and measurements of molecular wires, and related strategically engineered structures-molecular switches and memories. The experimental system relies on a thermodynamically driven self-assembling process to attach molecules onto substrate surfaces without intervention from outside. The following topics will be discussed: directed nanoscale manipulation of self-assembled molecules using scanning tunneling microscope; investigation on through-bond transport of nanoscale symmetric metal/conjugated self- assembled monolayers (SAM)/metal junctions, where non- Ohmic thermionic emission was observed to be the dominant process, with isocyanide-Pd contacts showing the lowest thermionic barrier of 0.22 eV; the first realization of robust and large reversible switching behavior in an electronic device that utilizes molecules containing redox centers as the active component, exhibiting negative differential resistance (NDR) and large on-off peak-to-valley ratio (PVR); observation of erasable storage of higher conductivity states in these redox- center containing molecular devices, and demonstration of a two-terminal electronically programmable and erasable molecular memory cell with long bit retention time.

  6. Analytical Performance Evaluation of Different Switch Solutions

    Directory of Open Access Journals (Sweden)

    Francisco Sans

    2013-01-01

    Full Text Available The virtualization of the network access layer has opened new doors in how we perceive networks. With this virtualization of the network, it is possible to transform a regular PC with several network interface cards into a switch. PC-based switches are becoming an alternative to off-the-shelf switches, since they are cheaper. For this reason, it is important to evaluate the performance of PC-based switches. In this paper, we present a performance evaluation of two PC-based switches, using Open vSwitch and LiSA, and compare their performance with an off-the-shelf Cisco switch. The RTT, throughput, and fairness for UDP are measured for both Ethernet and Fast Ethernet technologies. From this research, we can conclude that the Cisco switch presents the best performance, and both PC-based switches have similar performance. Between Open vSwitch and LiSA, Open vSwitch represents a better choice since it has more features and is currently actively developed.

  7. Streamer model for high voltage water switches

    International Nuclear Information System (INIS)

    Sazama, F.J.; Kenyon, V.L. III

    1979-01-01

    An electrical switch model for high voltage water switches has been developed which predicts streamer-switching effects that correlate well with water-switch data from Casino over the past four years and with switch data from recent Aurora/AMP experiments. Preclosure rounding and postclosure resistive damping of pulseforming line voltage waveforms are explained in terms of spatially-extensive, capacitive-coupling of the conducting streamers as they propagate across the gap and in terms of time-dependent streamer resistance and inductance. The arc resistance of the Casino water switch and of a gas switch under test on Casino was determined by computer fit to be 0.5 +- 0.1 ohms and 0.3 +- 0.06 ohms respectively, during the time of peak current in the power pulse. Energy lost in the water switch during the first pulse is 18% of that stored in the pulseforming line while similar energy lost in the gas switch is 11%. The model is described, computer transient analyses are compared with observed water and gas switch data and the results - switch resistance, inductance and energy loss during the primary power pulse - are presented

  8. Synchronization in complex networks with switching topology

    International Nuclear Information System (INIS)

    Wang, Lei; Wang, Qing-guo

    2011-01-01

    This Letter investigates synchronization issues of complex dynamical networks with switching topology. By constructing a common Lyapunov function, we show that local and global synchronization for a linearly coupled network with switching topology can be evaluated by the time average of second smallest eigenvalues corresponding to the Laplacians of switching topology. This result is quite powerful and can be further used to explore various switching cases for complex dynamical networks. Numerical simulations illustrate the effectiveness of the obtained results in the end. -- Highlights: → Synchronization of complex networks with switching topology is investigated. → A common Lyapunov function is established for synchronization of switching network. → The common Lyapunov function is not necessary to monotonically decrease with time. → Synchronization is determined by the second smallest eigenvalue of its Laplacian. → Synchronization criterion can be used to investigate various switching cases.

  9. Pinning Synchronization of Switched Complex Dynamical Networks

    Directory of Open Access Journals (Sweden)

    Liming Du

    2015-01-01

    Full Text Available Network topology and node dynamics play a key role in forming synchronization of complex networks. Unfortunately there is no effective synchronization criterion for pinning synchronization of complex dynamical networks with switching topology. In this paper, pinning synchronization of complex dynamical networks with switching topology is studied. Two basic problems are considered: one is pinning synchronization of switched complex networks under arbitrary switching; the other is pinning synchronization of switched complex networks by design of switching when synchronization cannot achieved by using any individual connection topology alone. For the two problems, common Lyapunov function method and single Lyapunov function method are used respectively, some global synchronization criteria are proposed and the designed switching law is given. Finally, simulation results verify the validity of the results.

  10. Field trial of 160 Gbit/s DWDM-based optical packet switching and transmission.

    Science.gov (United States)

    Furukawa, Hideaki; Wada, Naoya; Awaji, Yoshinari; Miyazaki, Tetsuya; Kong, Eddie; Chan, Peter; Man, Ray; Cincotti, Gabriella; Kitayama, Ken-ichi

    2008-07-21

    We demonstrated, for the first time, a field trial of 160 (16 lambda x 10) Gbit/s, fine granularity, DWDM-based optical packet switching and transmission by newly-developed burst-mode EDFAs and an optical packet switch prototype with multiple all-optical label processors. We achieved 64 km field transmission and switching of 160 (16 lambda x 10) Gbit/s DWDM-based optical packets encapsulating almost 10 Gbit/s IP packets with error-free operation (IP-packet-loss-rate <10(-6) and bit-error-rate <10(-9)).

  11. Bleeding complications after systematic switch of routine thromboprophylaxis for major orthopaedic surgery

    OpenAIRE

    Kistler, U; Kramers-de Quervain, I; Munzinger, U; Kucher, N

    2008-01-01

    The rate of bleeding complications after major orthopedic surgery approximates 2%. It is unclear whether a systematic switch of routine thromboprophylaxis has an impact on the rate of postoperative bleeding complications. We analyzed prospectively recorded postoperative bleeding complications and symptomatic venous thromboembolic events in 8,176 consecutive orthopedic patients at the Schulthess Clinic Zurich during a systematic switch of thromboprophylaxis from nadroparin to enoxaparin in the...

  12. Quantum switching of polarization in mesoscopic ferroelectrics

    International Nuclear Information System (INIS)

    Sa de Melo, C.A.

    1996-01-01

    A single domain of a uniaxial ferroelectric grain may be thought of as a classical permanent memory. At the mesoscopic level this system may experience considerable quantum fluctuations due to tunneling between two possible memory states, thus destroying the classical permanent memory effect. To study these quantum effects the concrete example of a mesoscopic uniaxial ferroelectric grain is discussed, where the orientation of the electric polarization determines two possible memory states. The possibility of quantum switching of the polarization in mesoscopic uniaxial ferroelectric grains is thus proposed. To determine the degree of memory loss, the tunneling rate between the two polarization states is calculated at zero temperature both in the absence and in the presence of an external static electric field. In addition, a discussion of crossover temperature between thermally activated behavior and quantum tunneling behavior is presented. And finally, environmental effects (phonons, defects, and surfaces) are also considered. copyright 1996 The American Physical Society

  13. Design of a bistable switch to control cellular uptake.

    Science.gov (United States)

    Oyarzún, Diego A; Chaves, Madalena

    2015-12-06

    Bistable switches are widely used in synthetic biology to trigger cellular functions in response to environmental signals. All bistable switches developed so far, however, control the expression of target genes without access to other layers of the cellular machinery. Here, we propose a bistable switch to control the rate at which cells take up a metabolite from the environment. An uptake switch provides a new interface to command metabolic activity from the extracellular space and has great potential as a building block in more complex circuits that coordinate pathway activity across cell cultures, allocate metabolic tasks among different strains or require cell-to-cell communication with metabolic signals. Inspired by uptake systems found in nature, we propose to couple metabolite import and utilization with a genetic circuit under feedback regulation. Using mathematical models and analysis, we determined the circuit architectures that produce bistability and obtained their design space for bistability in terms of experimentally tuneable parameters. We found an activation-repression architecture to be the most robust switch because it displays bistability for the largest range of design parameters and requires little fine-tuning of the promoters' response curves. Our analytic results are based on on-off approximations of promoter activity and are in excellent qualitative agreement with simulations of more realistic models. With further analysis and simulation, we established conditions to maximize the parameter design space and to produce bimodal phenotypes via hysteresis and cell-to-cell variability. Our results highlight how mathematical analysis can drive the discovery of new circuits for synthetic biology, as the proposed circuit has all the hallmarks of a toggle switch and stands as a promising design to control metabolic phenotypes across cell cultures. © 2015 The Author(s).

  14. Monolithic MZI-SOA hybrid switch for low-power and low-penalty operation.

    Science.gov (United States)

    Cheng, Q; Wonfor, A; Wei, J L; Penty, R V; White, I H

    2014-03-15

    We report the first experimental demonstration of a monolithically integrated hybrid dilated 2×2 modular optical switch using Mach-Zehnder modulators as low-loss 1×2 switching elements and short semiconductor optical amplifiers to provide additional extinction and gain. An excellent 40 dB cross-talk/extinction ratio is recorded with data-modulated signal-to-noise ratios of up to 44 dB in a 0.1 nm bandwidth. A switching time of 3 ns is demonstrated. Bit error rate studies show extremely low subsystem penalties of less than 0.1 dB, and studies indicate that, by using this hybrid switch building block, an 8×8 port switch could be achieved with 14 dB input power dynamic range for subsystem penalties of less than 0.5 dB.

  15. Torque Coordination Control during Braking Mode Switch for a Plug-in Hybrid Electric Vehicle

    Directory of Open Access Journals (Sweden)

    Yang Yang

    2017-10-01

    Full Text Available Hybrid vehicles usually have several braking systems, and braking mode switches are significant events during braking. It is difficult to coordinate torque fluctuations caused by mode switches because the dynamic characteristics of braking systems are different. In this study, a new type of plug-in hybrid vehicle is taken as the research object, and braking mode switches are divided into two types. The control strategy of type one is achieved by controlling the change rates of clutch hold-down and motor braking forces. The control strategy of type two is achieved by simultaneously changing the target braking torque during different mode switch stages and controlling the motor to participate in active coordination control. Finally, the torque coordination control strategy is modeled in MATLAB/Simulink, and the results show that the proposed control strategy has a good effect in reducing the braking torque fluctuation and vehicle shocks during braking mode switches.

  16. All-optical switching in a highly efficient parametric fiber mixer: design study.

    Science.gov (United States)

    Pejkic, Ana; Nissim, Ron R; Myslivets, Evgeny; Wiberg, Andreas O J; Alic, Nikola; Radic, Stojan

    2014-09-22

    Ultrafast all-optical switching in a highly nonlinear fiber with a longitudinally varied zero-dispersion wavelength was investigated theoretically and experimentally. We describe fiber-matched methodology for construction of a fast, low energy photon switch. The design relies on static and dynamic models and allows performance target selection, under constraints of physical fiber characteristic. The new design methodology was used to construct one-pump switch in the highly efficient parametric mixer. We demonstrate that such a parametric gate can operate at 100 GHz rate, with 2 aJ control energy, while achieving better than 50% extinction ratio. Theoretical analysis and experimental measurements indicate that accurate mapping of the fiber local dispersion is critical in optimizing the bandwidth and control energy of the switch. Switching performance limits are discussed and means for impairment mitigation are described.

  17. 1.114-gb/s time/space division switch system

    Science.gov (United States)

    Pawelski, Robert L.; Nordin, Ronald A.; Huisman, R. F.; Kelly, S.; Payne, William A.; Veach, R. S.

    1990-10-01

    Advanced digital communication services11 such as Broadband ISDN High Definition Television (HDTV) and enhanced data networking are expected to require high bandwidth and fast reconfiguration time switching centers available in the 1990''s. Digital GaAs IC''s can allow the implementation of these switching centers providing these services efficiently and at a low cost. The low cost arises from the reduction in hardware power maintenance etc. when the switch is designed to operate at the incoming data rate instead of at a lower rate. In order to utilize the capacity of a high bandwidth data link time division multiplexing is employed. This is a technique where multiple digital signals are interleaved (bit byte or block) on one data link. Clearly it is advantageous to have a switch that not only has a large bandwidth but can reconfigure at the data rate so as to provide bit byte or block switching functions thus being compatible with many different transmission formats. We present an experimental Time/Space Division Switch System capable of operating at over 1 Gb/s. Both custom and commercial Gallium Arsenide (GaAs) devices are used in the design of the various system functional blocks. These functional blocks include a Time Slot Interchanger (TSI) Time Multiplexed Switch (TMS) TMS Controller Multiplexer and Demultiplexers. In addition to the system overview we discuss such issues as printed circuit board microwave interconnections and CAD tools for high speed

  18. Mechanical switching of ferroelectric domains beyond flexoelectricity

    Science.gov (United States)

    Chen, Weijin; Liu, Jianyi; Ma, Lele; Liu, Linjie; Jiang, G. L.; Zheng, Yue

    2018-02-01

    The resurgence of interest in flexoelectricity has prompted discussions on the feasibility of switching ferroelectric domains 'non-electrically'. In this work, we perform three-dimensional thermodynamic simulations in combination with ab initio calculations and effective Hamiltonian simulations to demonstrate the great effects of surface screening and surface bonding on ferroelectric domain switching triggered by local tip loading. A three-dimensional simulation scheme has been developed to capture the tip-induced domain switching behavior in ferroelectric thin films by adequately taking into account the surface screening effect and surface bonding effect of the ferroelectric film, as well as the finite elastic stiffness of the substrate and the electrode layers. The major findings are as follows. (i) Compared with flexoelectricity, surface effects can be overwhelming and lead to much more efficient mechanical switching caused by tip loading. (ii) The surface-assisted mechanical switching can be bi-directional without the necessity of reversing strain gradients. (iii) A mode transition from local to propagating domain switching occurs when the screening below a critical value. A ripple effect of domain switching appears with the formation of concentric loop domains. (iv) The ripple effect can lead to 'domain interference' and a deterministic writing of confined loop domain patterns by local excitations. Our study reveals the hidden switching mechanisms of ferroelectric domains and the possible roles of surface in mechanical switching. The ripple effect of domain switching, which is believed to be general in dipole systems, broadens our current knowledge of domain engineering.

  19. Real exchange rate misalignments

    OpenAIRE

    Terra, Maria Cristina T.; Valladares, Frederico Estrella Carneiro

    2003-01-01

    This paper characterizes episodes of real appreciations and depreciations for a sample of 85 countries, approximately from 1960 to 1998. First, the equilibrium real exchange rate series are constructed for each country using Goldfajn and Valdes (1999) methodology (cointegration with fundamentals). Then, departures from equilibrium real exchange rate (misalignments) are obtained, and a Markov Switching Model is used to characterize the misalignments series as stochastic autor...

  20. Radiation-sensitive switching circuits

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.H.; Cockshott, C.P.

    1976-03-16

    A radiation-sensitive switching circuit has a light emitting diode which supplies light to a photo-transistor, the light being interrupted from time to time. When the photo-transistor is illuminated, current builds up and when this current reaches a predetermined value, a trigger circuit changes state. The peak output of the photo-transistor is measured and the trigger circuit is arranged to change state when the output of the device is a set proportion of the peak output, so as to allow for aging of the components. The circuit is designed to control the ignition system in an automobile engine.

  1. Radiation-sensitive switching circuits

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.H.; Cockshott, C.P.

    1976-03-16

    A radiation-sensitive switching circuit includes a light emitting diode which from time to time illuminates a photo-transistor, the photo-transistor serving when its output reaches a predetermined value to operate a trigger circuit. In order to allow for aging of the components, the current flow through the diode is increased when the output from the transistor falls below a known level. Conveniently, this is achieved by having a transistor in parallel with the diode, and turning the transistor off when the output from the phototransistor becomes too low. The circuit is designed to control the ignition system in an automobile engine.

  2. Laser-triggered vacuum switch

    Science.gov (United States)

    Brannon, Paul J.; Cowgill, Donald F.

    1990-01-01

    A laser-triggered vacuum switch has a material such as a alkali metal halide on the cathode electrode for thermally activated field emission of electrons and ions upon interaction with a laser beam, the material being in contact with the cathode with a surface facing the discharge gap. The material is preferably a mixture of KCl and Ti powders. The laser may either shine directly on the material, preferably through a hole in the anode, or be directed to the material over a fiber optic cable.

  3. MEMS switches having non-metallic crossbeams

    Science.gov (United States)

    Scardelletti, Maximillian C (Inventor)

    2009-01-01

    A RF MEMS switch comprising a crossbeam of SiC, supported by at least one leg above a substrate and above a plurality of transmission lines forming a CPW. Bias is provided by at least one layer of metal disposed on a top surface of the SiC crossbeam, such as a layer of chromium followed by a layer of gold, and extending beyond the switch to a biasing pad on the substrate. The switch utilizes stress and conductivity-controlled non-metallic thin cantilevers or bridges, thereby improving the RF characteristics and operational reliability of the switch. The switch can be fabricated with conventional silicon integrated circuit (IC) processing techniques. The design of the switch is very versatile and can be implemented in many transmission line mediums.

  4. On formalism and stability of switched systems

    DEFF Research Database (Denmark)

    Leth, John-Josef; Wisniewski, Rafal

    2012-01-01

    In this paper, we formulate a uniform mathematical framework for studying switched systems with piecewise linear partitioned state space and state dependent switching. Based on known results from the theory of differential inclusions, we devise a Lyapunov stability theorem suitable for this class...... of switched systems. With this, we prove a Lyapunov stability theorem for piecewise linear switched systems by means of a concrete class of Lyapunov functions. Contrary to existing results on the subject, the stability theorems in this paper include Filippov (or relaxed) solutions and allow infinite switching...... in finite time. Finally, we show that for a class of piecewise linear switched systems, the inertia of the system is not sufficient to determine its stability. A number of examples are provided to illustrate the concepts discussed in this paper....

  5. Switching control of an R/C hovercraft: stabilization and smooth switching.

    Science.gov (United States)

    Tanaka, K; Iwasaki, M; Wang, H O

    2001-01-01

    This paper presents stable switching control of an radio-controlled (R/C) hovercraft that is a nonholonomic (nonlinear) system. To exactly represent its nonlinear dynamics, more importantly, to maintain controllability of the system, we newly propose a switching fuzzy model that has locally Takagi-Sugeno (T-S) fuzzy models and switches them according to states, external variables, and/or time. A switching fuzzy controller is constructed by mirroring the rule structure of the switching fuzzy model of an R/C hovercraft. We derive linear matrix inequality (LMI) conditions for ensuring the stability of the closed-loop system consisting of a switching fuzzy model and controller. Furthermore, to guarantee smooth switching of control input at switching boundaries, we also derive a smooth switching condition represented in terms of LMIs. A stable switching fuzzy controller satisfying the smooth switching condition is designed by simultaneously solving both of the LMIs. The simulation and experimental results for the trajectory control of an R/C hovercraft show the validity of the switching fuzzy model and controller design, particularly, the smooth switching condition.

  6. AN ANALYTICAL STUDY OF SWITCHING TRACTION MOTORS

    Directory of Open Access Journals (Sweden)

    V. M. Bezruchenko

    2010-03-01

    Full Text Available The analytical study of switching of the tractive engines of electric locomotives is conducted. It is found that the obtained curves of change of current of the sections commuted correspond to the theory of average rectilinear switching. By means of the proposed method it is possible on the stage of design of tractive engines to forecast the quality of switching and to correct it timely.

  7. Switching X-Ray Tubes Remotely

    Science.gov (United States)

    Bulthuis, Ronald V.

    1990-01-01

    Convenient switch and relay circuit reduces risk of accidents. Proposed switching circuit for x-ray inspection system enables operator to change electrical connections to x-ray tubes remotely. Operator simply flips switch on conveniently-located selector box to change x-ray heads. Indicator lights on selector box show whether 160 or 320-kV head connected. Relays in changeover box provides proper voltages and coolants. Chance of making wrong connections and damaging equipment eliminated.

  8. Switched reluctance drives for electric vehicle applications

    OpenAIRE

    Andrada Gascón, Pedro; Torrent Burgués, Marcel; Blanqué Molina, Balduino; Perat Benavides, Josep Ignasi

    2003-01-01

    Electric vehicles are the only alternative for a clean, efficient and environmentally friendly urban transport system. With the increasing interest in electric drives for electric vehicle propulsion. This paper first tries to explain why the switched reluctance drive is a strong candidate for electric vehicle applications. It then gives switched reluctance drive design guidelines for battery or fuel cell operated electric vehicles. Finally, it presents the design and simulation of a switched ...

  9. Optical Multidimensional Switching for Data Center Networks

    DEFF Research Database (Denmark)

    Kamchevska, Valerija

    2017-01-01

    , the limitations of previously proposed optical subwavelength switching technologies are discussed and a novel concept of optical time division multiplexed switching is proposed. A detailed elaboration of the envisioned scheme is given, with a special focus on the problem of synchronization. A novel...... synchronization algorithm for the Hi-Ring architecture is proposed and experimentally validated. Furthermore, software controlled switching in the data plane is experimentally demonstrated when the proposed algorithm is used for synchronization. Finally, integration is discussed from two different perspectives...

  10. Monitoring Mellanox Infiniband SX6036 switches

    CERN Document Server

    Agapiou, Marinos

    2017-01-01

    The SX6036 switches addressed by my project, are part of a fully non-blocking fat-tree cluster consisting of 72 servers and 6 Mellanox SX6036 Infiniband switches. My project is about retrieving the appropriate metrics from the Infiniband switch cluster, ingesting the data to Collectd and after my data are being transfered to CERN Database, they are being visualized via Grafana Dashboards.

  11. Evolution of a Fluctuating Population in a Randomly Switching Environment

    Science.gov (United States)

    Wienand, Karl; Frey, Erwin; Mobilia, Mauro

    2017-10-01

    Environment plays a fundamental role in the competition for resources, and hence in the evolution of populations. Here, we study a well-mixed, finite population consisting of two strains competing for the limited resources provided by an environment that randomly switches between states of abundance and scarcity. Assuming that one strain grows slightly faster than the other, we consider two scenarios—one of pure resource competition, and one in which one strain provides a public good—and investigate how environmental randomness (external noise) coupled to demographic (internal) noise determines the population's fixation properties and size distribution. By analytical means and simulations, we show that these coupled sources of noise can significantly enhance the fixation probability of the slower-growing species. We also show that the population size distribution can be unimodal, bimodal, or multimodal and undergoes noise-induced transitions between these regimes when the rate of switching matches the population's growth rate.

  12. Numerical modelling of passively Q-switched intracavity Raman lasers

    International Nuclear Information System (INIS)

    Ding Shuanghong; Zhang Xingyu; Wang Qingpu; Zhang Jun; Wang Shumei; Liu Yuru; Zhang Xuehui

    2007-01-01

    Assuming intracavity photon densities to be of Gaussian spatial distributions, the space-dependent rate equations of passively Q-switched intracavity Raman lasers are deduced for the first time for the pumping beams of Gaussian and top-head spatial distributions, respectively. The new rate equations are normalized and solved numerically to investigate the influences of the normalized initial population inversion density, normalized Raman gain coefficient, saturable absorber parameter, beam size ratio of pump to fundamental laser and loss ratio of the first Stokes to fundamental laser on the pulse parameters of the first Stokes. The results of the Gaussian and top-head pumpings show similar trends despite some discrepancies. The new theories and numerical results will help design passively Q-switched intracavity Raman lasers of high performance

  13. Evolution of a Fluctuating Population in a Randomly Switching Environment.

    Science.gov (United States)

    Wienand, Karl; Frey, Erwin; Mobilia, Mauro

    2017-10-13

    Environment plays a fundamental role in the competition for resources, and hence in the evolution of populations. Here, we study a well-mixed, finite population consisting of two strains competing for the limited resources provided by an environment that randomly switches between states of abundance and scarcity. Assuming that one strain grows slightly faster than the other, we consider two scenarios-one of pure resource competition, and one in which one strain provides a public good-and investigate how environmental randomness (external noise) coupled to demographic (internal) noise determines the population's fixation properties and size distribution. By analytical means and simulations, we show that these coupled sources of noise can significantly enhance the fixation probability of the slower-growing species. We also show that the population size distribution can be unimodal, bimodal, or multimodal and undergoes noise-induced transitions between these regimes when the rate of switching matches the population's growth rate.

  14. Large optical 3D MEMS switches in access networks

    Science.gov (United States)

    Madamopoulos, Nicholas; Kaman, Volkan; Yuan, Shifu; Jerphagnon, Olivier; Helkey, Roger; Bowers, John E.

    2007-09-01

    Interest is high among residential customers and businesses for advanced, broadband services such as fast Internet access, electronic commerce, video-on-demand, digital broadcasting, teleconferencing and telemedicine. In order to satisfy such growing demand of end-customers, access technologies such as fiber-to-the-home/building (FTTH/B) are increasingly being deployed. Carriers can reduce maintenance costs, minimize technology obsolescence and introduce new services easily by reducing active elements in the fiber access network. However, having a passive optical network (PON) also introduces operational and maintenance challenges. Increased diagnostic monitoring capability of the network becomes a necessity as more and more fibers are provisioned to deliver services to the end-customers. This paper demonstrates the clear advantages that large 3D optical MEMS switches offer in solving these access network problems. The advantages in preventative maintenance, remote monitoring, test and diagnostic capability are highlighted. The low optical insertion loss for all switch optical connections of the switch enables the monitoring, grooming and serving of a large number of PON lines and customers. Furthermore, the 3D MEMS switch is transparent to optical wavelengths and data formats, thus making it easy to incorporate future upgrades, such higher bit rates or DWDM overlay to a PON.

  15. Stochastic switching induced adaptation in a starved Escherichia coli population.

    Directory of Open Access Journals (Sweden)

    Yoshihiro Shimizu

    Full Text Available Population adaptation can be determined by stochastic switching in living cells. To examine how stochastic switching contributes to the fate decision for a population under severe stress, we constructed an Escherichia coli strain crucially dependent on the expression of a rewired gene. The gene essential for tryptophan biosynthesis, trpC, was removed from the native regulatory unit, the Trp operon, and placed under the extraneous control of the lactose utilisation network. Bistability of the network provided the cells two discrete phenotypes: the induced and suppressed level of trpC. The two phenotypes permitted the cells to grow or not, respectively, under conditions of tryptophan depletion. We found that stochastic switching between the two states allowed the initially suppressed cells to form a new population with induced trpC in response to tryptophan starvation. However, the frequency of the transition from suppressed to induced state dropped off dramatically in the starved population, in comparison to that in the nourished population. This reduced switching rate was compensated by increasing the initial population size, which probably provided the cell population more chances to wait for the rarely appearing fit cells from the unfit cells. Taken together, adaptation of a starved bacterial population because of stochasticity in the gene rewired from the ancient regulon was experimentally confirmed, and the nutritional status and the population size played a great role in stochastic adaptation.

  16. High Performance Gigabit Ethernet Switches for DAQ Systems

    CERN Document Server

    Barczyk, Artur

    2005-01-01

    Commercially available high performance Gigabit Ethernet (GbE) switches are optimized mostly for Internet and standard LAN application traffic. DAQ systems on the other hand usually make use of very specific traffic patterns, with e.g. deterministic arrival times. Industry's accepted loss-less limit of 99.999% may be still unacceptably high for DAQ purposes, as e.g. in the case of the LHCb readout system. In addition, even switches passing this criteria under random traffic can show significantly higher loss rates if subject to our traffic pattern, mainly due to buffer memory limitations. We have evaluated the performance of several switches, ranging from "pizza-box" devices with 24 or 48 ports up to chassis based core switches in a test-bed capable to emulate realistic traffic patterns as expected in the readout system of our experiment. The results obtained in our tests have been used to refine and parametrize our packet level simulation of the complete LHCb readout network. In this paper we report on the...

  17. Current-induced switching in transport through anisotropic magnetic molecules

    Science.gov (United States)

    Bode, Niels; Arrachea, Liliana; Lozano, Gustavo S.; Nunner, Tamara S.; von Oppen, Felix

    2012-03-01

    Anisotropic single-molecule magnets may be thought of as molecular switches, with possible applications to molecular spintronics. In this paper, we consider current-induced switching in single-molecule junctions containing an anisotropic magnetic molecule. We assume that the carriers interact with the magnetic molecule through the exchange interaction and focus on the regime of high currents in which the molecular spin dynamics is slow compared to the time which the electrons spend on the molecule. In this limit, the molecular spin obeys a nonequilibrium Langevin equation which takes the form of a generalized Landau-Lifshitz-Gilbert equation and which we derive microscopically by means of a nonequilibrium Born-Oppenheimer approximation. We exploit this Langevin equation to identify the relevant switching mechanisms and to derive the current-induced switching rates. As a by-product, we also derive S-matrix expressions for the various torques entering into the Landau-Lifshitz-Gilbert equation which generalize previous expressions in the literature to nonequilibrium situations.

  18. "Switching on" the properties of single-molecule magnetism in triangular manganese(III) complexes.

    Science.gov (United States)

    Stamatatos, Theocharis C; Foguet-Albiol, Dolos; Lee, Sheng-Chiang; Stoumpos, Constantinos C; Raptopoulou, Catherine P; Terzis, Aris; Wernsdorfer, Wolfgang; Hill, Stephen O; Perlepes, Spyros P; Christou, George

    2007-08-01

    The reaction between oxide-centered, triangular [MnIII3O(O2CR)6(py)3](ClO4) (R = Me (1), Et (2), Ph (3)) compounds and methyl 2-pyridyl ketone oxime (mpkoH) affords a new family of Mn/carboxylato/oximato complexes, [MnIII3O(O2CR)3(mpko)3](ClO4) [R = Me (4), Et (5), and Ph (6)]. As in 1-3, the cations of 4-6 contain an [MnIII3(mu3-O)]7+ triangular core, but with each Mn2 edge now bridged by an eta1:eta1:mu-RCO2- and an eta1:eta1:eta1:mu-mpko- group. The tridentate binding mode of the latter causes a buckling of the formerly planar [MnIII3(mu3-O)]7+ core, resulting in a relative twisting of the three MnIII octahedra and the central O2- ion now lying approximately 0.3 A above the Mn3 plane. This structural distortion leads to ferromagnetic exchange interactions within the molecule and a resulting S = 6 ground state. Fits of dc magnetization data for 4-6 collected in the 1.8-10.0 K and 10-70 kG ranges confirmed S = 6 ground states, and gave the following D and g values: -0.34 cm(-1) and 1.92 for 4, -0.34 cm(-1) and 1.93 for 5, and -0.35 cm(-1) and 1.99 for 6, where D is the axial zero-field splitting (anisotropy) parameter. Complexes 4-6 all exhibit frequency-dependent out-of-phase (chi" M) ac susceptibility signals suggesting them possibly to be single-molecule magnets (SMMs). Relaxation rate vs T data for complex 4 down to 1.8 K obtained from the chi" M vs T studies were supplemented with rate vs T data measured to 0.04 K via magnetization vs time decay studies, and these were used to construct Arrhenius plots from which was obtained the effective barrier to relaxation (Ueff) of 10.9 K. Magnetization vs dc field sweeps on single-crystals of 4.3CH2Cl2 displayed hysteresis loops exhibiting steps due to quantum tunneling of magnetization (QTM). The loops were essentially temperature-independent below approximately 0.3 K, indicating only ground-state QTM between the lowest-lying Ms = +/-6 levels. Complexes 4-6 are thus confirmed as the first triangular SMMs. High

  19. Atomic crystals resistive switching memory

    International Nuclear Information System (INIS)

    Liu Chunsen; Zhang David Wei; Zhou Peng

    2017-01-01

    Facing the growing data storage and computing demands, a high accessing speed memory with low power and non-volatile character is urgently needed. Resistive access random memory with 4F 2 cell size, switching in sub-nanosecond, cycling endurances of over 10 12 cycles, and information retention exceeding 10 years, is considered as promising next-generation non-volatile memory. However, the energy per bit is still too high to compete against static random access memory and dynamic random access memory. The sneak leakage path and metal film sheet resistance issues hinder the further scaling down. The variation of resistance between different devices and even various cycles in the same device, hold resistive access random memory back from commercialization. The emerging of atomic crystals, possessing fine interface without dangling bonds in low dimension, can provide atomic level solutions for the obsessional issues. Moreover, the unique properties of atomic crystals also enable new type resistive switching memories, which provide a brand-new direction for the resistive access random memory. (topical reviews)

  20. Atomic battery with beam switching

    International Nuclear Information System (INIS)

    Edling, E.A.; McKenna, R.P.; Peterick, E.Th. Jr.; Trexler, F.D.

    1984-01-01

    An electric power generating apparatus that is powered primarily by the emission of electrically charged particles from radio-active materials enclosed in an evacuated vessel of glass or the like. An arrangement of reflecting electrodes causes a beam of particles to switch back and forth at a high frequency between two collecting electrodes that are connected to a resonating tuned primary circuit consisting of an inductor with resonating capacitor. The reflecting electrodes are energized in the proper phase relationship to the collecting electrodes to insure sustained oscillation by means of a secondary winding coupled inductively to the primary winding and connected to the reflecting electrodes. Power may be drawn from the circuit at a stepped down voltage from a power take-off winding that is coupled to the primary winding. The disclosure also describes a collecting electrode arrangement consisting of multiple spatially separated electrodes which together serve to capture a maximum of the available particle energy. A self-starting arrangement for start of oscillations is described. A specially adapted version of the invention utilizes two complementary beams of oppositely charged particles which are switched alternatingly between the collecting electrodes

  1. Stochastic multistep polarization switching in ferroelectrics

    Science.gov (United States)

    Genenko, Y. A.; Khachaturyan, R.; Schultheiß, J.; Ossipov, A.; Daniels, J. E.; Koruza, J.

    2018-04-01

    Consecutive stochastic 90° polarization switching events, clearly resolved in recent experiments, are described by a nucleation and growth multistep model. It extends the classical Kolmogorov-Avrami-Ishibashi approach and includes possible consecutive 90°- and parallel 180° switching events. The model predicts the results of simultaneous time-resolved macroscopic measurements of polarization and strain, performed on a tetragonal Pb (Zr ,Ti ) O3 ceramic in a wide range of electric fields over a time domain of seven orders of magnitude. It allows the determination of the fractions of individual switching processes, their characteristic switching times, activation fields, and respective Avrami indices.

  2. The increased importance of sector switching

    DEFF Research Database (Denmark)

    Frederiksen, Anders; Hansen, Jesper Rosenberg

    2017-01-01

    Sector switching is an important phenomenon that casts light on public–private differences. Yet our knowledge about its prevalence and trends is limited. We study sector switching using unique Danish register-based employer–employee data covering more than 25 years. We find that sector switching...... constitutes 18.5% of all job-to-job mobility, and the trend is increasing both from public to private and from private to public. Sector switching is also generally increasing for middle managers, but for administrative professionals only the flows from private to public increase and for top managers only...

  3. Low-Voltage Switched-Capacitor Circuits

    DEFF Research Database (Denmark)

    Bidari, E.; Keskin, M.; Maloberti, F.

    1999-01-01

    Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications.......Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications....

  4. Heat switch technology for cryogenic thermal management

    Science.gov (United States)

    Shu, Q. S.; Demko, J. A.; E Fesmire, J.

    2017-12-01

    Systematic review is given of development of novel heat switches at cryogenic temperatures that alternatively provide high thermal connection or ideal thermal isolation to the cold mass. These cryogenic heat switches are widely applied in a variety of unique superconducting systems and critical space applications. The following types of heat switch devices are discussed: 1) magnetic levitation suspension, 2) shape memory alloys, 3) differential thermal expansion, 4) helium or hydrogen gap-gap, 5) superconducting, 6) piezoelectric, 7) cryogenic diode, 8) magneto-resistive, and 9) mechanical demountable connections. Advantages and limitations of different cryogenic heat switches are examined along with the outlook for future thermal management solutions in materials and cryogenic designs.

  5. Mechanism of single atom switch on silicon

    DEFF Research Database (Denmark)

    Quaade, Ulrich; Stokbro, Kurt; Thirstrup, C.

    1998-01-01

    We demonstrate single atom switch on silicon which operates by displacement of a hydrogen atom on the silicon (100) surface at room temperature. We find two principal effects by which the switch is controlled: a pronounced maximum of the switching probability as function of sample bias...... and a preferred direction of switching as function of STM tip position. Based on first principles calculations, are show that this behaviour is due to a novel mechanism involving an electronic excitation of a localized surface resonance. (C) 1998 Elsevier Science B.V. All rights reserved....

  6. Clocking Scheme for Switched-Capacitor Circuits

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    1998-01-01

    A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed.......A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed....

  7. All-fiber optical mode switching based on cascaded mode selective couplers for short-reach MDM networks

    Science.gov (United States)

    Ren, Fang; Li, Juhao; Wu, Zhongying; Yu, Jinyi; Mo, Qi; Wang, Jianping; He, Yongqi; Chen, Zhangyuan; Li, Zhengbin

    2017-04-01

    We propose and experimentally demonstrate an all-fiber optical mode switching structure supporting independent switching, exchanging, adding, and dropping functionalities in which each mode can be switched individually. The mode switching structure consists of cascaded mode selective couplers (MSCs) capable of exciting and selecting specific higher order modes in few-mode fibers with high efficiency and one multiport optical switch routing the independent spatial modes to their destinations. The data carried on three different spatial modes can be switched, exchanged, added, and dropped through this all-fiber structure. For this experimental demonstration, optical on-off-keying (OOK) signals at 10-Gb/s carried on three spatial modes are successfully processed with open and clear eye diagrams. The mode switch exhibits power penalties of less than 3.1 dB after through operation, less than 2.7 dB after exchange operation, less than 2.8 dB after switching operation, and less than 1.6 dB after mode adding and dropping operations at the bit-error rate (BER) of 10-3, while all three channels carried on three spatial modes are simultaneously routed. The proposed structure, compatible with current optical switching networks based on single-mode fibers, can potentially be used to expand the switching scalability in advanced and flexible short-reach mode-division multiplexing-based networks.

  8. Automatic switching between noise classification and speech enhancement for hearing aid devices.

    Science.gov (United States)

    Saki, Fatemeh; Kehtarnavaz, Nasser

    2016-08-01

    This paper presents a voice activity detector (VAD) for automatic switching between a noise classifier and a speech enhancer as part of the signal processing pipeline of hearing aid devices. The developed VAD consists of a computationally efficient feature extractor and a random forest classifier. Previously used signal features as well as two newly introduced signal features are extracted and fed into the classifier to perform automatic switching. This switching approach is compared to two popular VADs. The results obtained indicate the introduced approach outperforms these existing approaches in terms of both detection rate and processing time.

  9. Low jitter spark gap switch for repetitively pulsed parallel capacitor banks

    International Nuclear Information System (INIS)

    Rohwein, G.J.

    1980-01-01

    A two-section air insulated spark gap has been developed for switching multi-kilojoule plus-minus charged parallel capacitor banks which operate continuously at pulse rates up to 20 pps. The switch operates with less than 2 ns jitter, recovers its dielectric strength within 2 to 5 ms and has not shown degraded performance in sequential test runs totaling over a million shots. Its estimated life with copper electrodes is > 10 7 shots. All preliminary tests indicate that the switch is suitable for continuous running multi-kilojoule systems operating to at least 20 pps

  10. 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...

  11. Thermally activated switching in the presence of non-Gaussian noise

    Science.gov (United States)

    Billings, Lora; Dykman, Mark I.; Schwartz, Ira B.

    2008-11-01

    We study the effect of a non-Gaussian noise on interstate switching activated primarily by Gaussian noise. Even weak non-Gaussian noise can strongly change the switching rate. The effect is determined by all moments of the noise distribution. It is expressed in a closed form in terms of the noise characteristic functional. The analytical results are compared with the results of simulations for an overdamped system driven by white Gaussian noise and a Poisson noise. Switching induced by a purely Poisson noise is also discussed.

  12. Experimental Validation of Modelled Fluid Forces in Fast Switching Hydraulic On/Off Valves

    DEFF Research Database (Denmark)

    Nørgård, Christian; Bech, Michael Møller; Roemer, Daniel Beck

    2015-01-01

    A prototype of a fast switching valve for a digital hydraulic machine has been designed and manufactured. The valve is composed of an annular seat plunger connected with a moving coil actuator as the force producing element. The valve prototype is designed for flow rates of 600 l/min with less than...... validate a transient computational fluid dynamics (CFD) model of the fluid forces that oppose the valve plunger when moving rapidly through the surrounding oil during switching. Due to the fast switching of the valve, the fluid forces which oppose plunger movement increases drastically as the plunger...

  13. 49 CFR 236.6 - Hand-operated switch equipped with switch circuit controller.

    Science.gov (United States)

    2010-10-01

    ... controller. 236.6 Section 236.6 Transportation Other Regulations Relating to Transportation (Continued... switch circuit controller. Hand-operated switch equipped with switch circuit controller connected to the point, or with facing-point lock and circuit controller, shall be so maintained that when point is open...

  14. Timing and amplitude jitter in a gain-switched multimode semiconductor laser

    Science.gov (United States)

    Wada, Kenji; Kitagawa, Naoaki; Matsukura, Satoru; Matsuyama, Tetsuya; Horinaka, Hiromichi

    2016-04-01

    The differences in timing jitter between a gain-switched single-mode semiconductor laser and a gain-switched multimode semiconductor laser are examined using rate equations that include Langevin noise. The timing jitter in a gain-switched multimode semiconductor laser is found to be effectively suppressed by a decrease in the coherence time of the amplified spontaneous emission (ASE) based on a broad bandwidth of multimode oscillation. Instead, fluctuations in the ASE cause amplitude jitter in the pulse components of the respective modes. A pulse train of gain-switched pulses from a multimode semiconductor laser with timing jitter is equivalently simulated by assuming a high spontaneous emission factor and a short coherence time of the ASE in the single-mode semiconductor laser rate equations.

  15. Bleeding complications after systematic switch of routine thromboprophylaxis for major orthopaedic surgery.

    Science.gov (United States)

    Kistler, Urs; Kramers-de Quervain, Inès; Munzinger, Urs; Kucher, Nils

    2008-06-01

    The rate of bleeding complications after major orthopedic surgery approximates 2%. It is unclear whether a systematic switch of routine thromboprophylaxis has an impact on the rate of postoperative bleeding complications. We analyzed prospectively recorded postoperative bleeding complications and symptomatic venous thromboembolic events in 8,176 consecutive orthopedic patients at the Schulthess Clinic Zurich during a systematic switch of thromboprophylaxis from nadroparin to enoxaparin in the year 2004. Overall, 3,893 patients received nadroparin in the first nine-month observation period before the switch and 4,283 patients received enoxaparin in the second nine-month observation period after the switch. Overall, 96 (2.5%) patients in the first period and 70 (1.6%) patients in the second period suffered a postoperative bleeding complication requiring surgical revision, puncture, or transfusion (p postoperative bleeding complications and therefore was accompanied by high patient safety.

  16. Superconducting switch and amplifier device

    International Nuclear Information System (INIS)

    Faris, S.M.

    1982-01-01

    An amplifying or switching superconductive device is described whose current-voltage characteristic is drastically altered by heavy injection of excess energetic quasi-particles. In this device, the superconducting bandgap of a superconducting layer is greatly altered by overinjection of energetic quasi-particles so that the bandgap changes greatly with respect to its thermal equilibrium value, and in most cases is made to vanish. In a preferred embodiment, a three electrode device is fabricated where at least one of the electrodes is a superconductor. Tunnel barriers are located between the electrodes. A first tunnel junction is used to heavily inject energetic quasi-particles into the superconducting electrode to change its superconducting bandgap drastically. In turn, this greatly modifies the currentvoltage characteristics of the second tunnel junction. This device can be used to provide logic circuits, or as an amplifier, and has an output sufficiently large that it can drive other similar devices

  17. Switching model predictive attitude control for a quadrotor helicopter subject to atmospheric disturbances

    OpenAIRE

    Alexis, Kostas; Nikolakopoulos, George; Tzes, Anthony

    2011-01-01

    In this article a Switching Model Predictive Attitude Controller for an Unmanned quadrotor Helicopter subject to atmospheric disturbances is presented. The proposed control scheme is computed based on a Piecewise Affine (PWA) model of the quadrotor’s attitude dynamics, where the effects of the atmospheric turbulence are taken into consideration as additive disturbances. The switchings among the PWA models are ruled by the rate of the rotation angles and for each PWA system a corresponding mod...

  18. Dissipation enhanced vibrational sensing in an olfactory molecular switch

    International Nuclear Information System (INIS)

    Chęcińska, Agata; Heaney, Libby; Pollock, Felix A.; Nazir, Ahsan

    2015-01-01

    Motivated by a proposed olfactory mechanism based on a vibrationally activated molecular switch, we study electron transport within a donor-acceptor pair that is coupled to a vibrational mode and embedded in a surrounding environment. We derive a polaron master equation with which we study the dynamics of both the electronic and vibrational degrees of freedom beyond previously employed semiclassical (Marcus-Jortner) rate analyses. We show (i) that in the absence of explicit dissipation of the vibrational mode, the semiclassical approach is generally unable to capture the dynamics predicted by our master equation due to both its assumption of one-way (exponential) electron transfer from donor to acceptor and its neglect of the spectral details of the environment; (ii) that by additionally allowing strong dissipation to act on the odorant vibrational mode, we can recover exponential electron transfer, though typically at a rate that differs from that given by the Marcus-Jortner expression; (iii) that the ability of the molecular switch to discriminate between the presence and absence of the odorant, and its sensitivity to the odorant vibrational frequency, is enhanced significantly in this strong dissipation regime, when compared to the case without mode dissipation; and (iv) that details of the environment absent from previous Marcus-Jortner analyses can also dramatically alter the sensitivity of the molecular switch, in particular, allowing its frequency resolution to be improved. Our results thus demonstrate the constructive role dissipation can play in facilitating sensitive and selective operation in molecular switch devices, as well as the inadequacy of semiclassical rate equations in analysing such behaviour over a wide range of parameters

  19. Unity power factor switching regulator

    Science.gov (United States)

    Rippel, Wally E. (Inventor)

    1983-01-01

    A single or multiphase boost chopper regulator operating with unity power factor, for use such as to charge a battery is comprised of a power section for converting single or multiphase line energy into recharge energy including a rectifier (10), one inductor (L.sub.1) and one chopper (Q.sub.1) for each chopper phase for presenting a load (battery) with a current output, and duty cycle control means (16) for each chopper to control the average inductor current over each period of the chopper, and a sensing and control section including means (20) for sensing at least one load parameter, means (22) for producing a current command signal as a function of said parameter, means (26) for producing a feedback signal as a function of said current command signal and the average rectifier voltage output over each period of the chopper, means (28) for sensing current through said inductor, means (18) for comparing said feedback signal with said sensed current to produce, in response to a difference, a control signal applied to the duty cycle control means, whereby the average inductor current is proportionate to the average rectifier voltage output over each period of the chopper, and instantaneous line current is thereby maintained proportionate to the instantaneous line voltage, thus achieving a unity power factor. The boost chopper is comprised of a plurality of converters connected in parallel and operated in staggered phase. For optimal harmonic suppression, the duty cycles of the switching converters are evenly spaced, and by negative coupling between pairs 180.degree. out-of-phase, peak currents through the switches can be reduced while reducing the inductor size and mass.

  20. Modelling switching power converters as complementarity systems

    NARCIS (Netherlands)

    Camlibel, Mehmet; Iannelli, Luigi; Vasca, Francesco

    2004-01-01

    Switched complementarity models of linear circuits with ideal diodes and/or ideal switches allow one to study well-posedness and stability issues for these circuits by employing the complementarity problems of the mathematical programming. In this paper, we demonstrate that other types of typical

  1. Low-Voltage Switched-Capacitor Circuits

    DEFF Research Database (Denmark)

    Bidari, E.; Keskin, M.; Maloberti, F.

    1999-01-01

    Switched-capacitor stages are described which can function with very low (typically 1 V) supply voltages, without using voltage boosting or switched op-amps. Simulations indicate that high performance may be achieved using these circuits in filter or data converter applications....

  2. Tutorial: Integrated-photonic switching structures

    Science.gov (United States)

    Soref, Richard

    2018-02-01

    Recent developments in waveguided 2 × 2 and N × M photonic switches are reviewed, including both broadband and narrowband resonant devices for the Si, InP, and AlN platforms. Practical actuation of switches by electro-optical and thermo-optical techniques is discussed. Present datacom-and-computing applications are reviewed, and potential applications are proposed for chip-scale photonic and optoelectronic integrated switching networks. Potential is found in the reconfigurable, programmable "mesh" switches that enable a promising group of applications in new areas beyond those in data centers and cloud servers. Many important matrix switches use gated semiconductor optical amplifiers. The family of broadband, directional-coupler 2 × 2 switches featuring two or three side-coupled waveguides deserves future experimentation, including devices that employ phase-change materials. The newer 2 × 2 resonant switches include standing-wave resonators, different from the micro-ring traveling-wave resonators. The resonant devices comprise nanobeam interferometers, complex-Bragg interferometers, and asymmetric contra-directional couplers. Although the fast, resonant devices offer ultralow switching energy, ˜1 fJ/bit, they have limitations. They require several trade-offs when deployed, but they do have practical application.

  3. Novel RF-MEMS capacitive switching structures

    NARCIS (Netherlands)

    Rottenberg, X.; Jansen, Henricus V.; Fiorini, P.; De Raedt, W.; Tilmans, H.A.C.

    2002-01-01

    This paper reports on novel RF-MEMS capacitive switching devices implementing an electrically floating metal layer covering the dielectric to ensure intimate contact with the bridge in the down state. This results in an optimal switch down capacitance and allows optimisation of the down/up

  4. Internal Backpressure for Terabit Switch Fabrics

    DEFF Research Database (Denmark)

    Fagertun, Anna Manolova; Ruepp, Sarah Renée; Rytlig, Andreas

    2012-01-01

    This paper proposes and analyzes the efficiency of novel backpressure schemes for Terabit switch fabrics. The proposed schemes aim at buffer optimization under uniform traffic distribution with Bernoulli packet arrival process. Results show that a reduction of the needed maximum buffer capacity w...... with up to 47% can be achieved with switch-internal backpressure mechanisms at the expense of a small control overhead....

  5. Ice-release coating for disconnect switches

    Science.gov (United States)

    Mundon, J. L.

    1980-03-01

    Several coatings for ice release, heat dissipation, thermal cycling, and outdoor weathering properties were evaluated. The coating having the most desired performance were applied to full scale switch components. The full scale switches were tested for ice performance and heat dissipation and the results were compared with those on identical switches with uncoated components. The coating chosen for application to switch components was installed on several switches for field evaluation during the winter of 1979 and 1980. It was offered for commercial application for installation to existing switch installations. Results indicate that the coating also exhibits excellent heat dissipation properties and may be used to improve heat dissipation of switch blades and other components. The coating material is unaffected by sunlight; it is a two component, Teflon-filled polyurethane that is available from two sources. The material is currently used for a variety of purposes, such as: aircraft wing and leading edge areas, hydrofoils, conveyor chutes and many others. Light gray in color, it is an excellent heat dissipator and matches the gray insulators used with most switches.

  6. Proceedings of the switched power workshop

    International Nuclear Information System (INIS)

    Fernow, R.C.

    1988-01-01

    These proceedings contain most of the presentations given at a workshop on the current state of research in techniques for switched power acceleration. The proceedings are divided, as was the workshop itself, into two parts. Part 1, contains the latest results from a number of groups active in switched power research. The major topic here is a method for switching externally supplied power onto a transmission line. Advocates for vacuum photodiode switching, solid state switching, gas switching, and synthetic pulse generation are all presented. Other important areas of research described in this section concern: external electrical and laser pulsing systems; the properties of the created electromagnetic pulse; structures used for transporting the electromagnetic pulse to the region where the electron beam is located; and possible applications. Part 2 of the proceedings considers the problem of designing a high brightness electron gun using switched power as the power source. This is an important first step in demonstrating the usefulness of switched power techniques for accelerator physics. In addition such a gun could have immediate practical importance for advanced acceleration studies since the brightness could exceed that of present sources by several orders of magnitude. I would like to take this opportunity to thank Kathleen Tuohy and Patricia Tuttle for their assistance in organizing and running the workshop. Their tireless efforts contribute greatly to a very productive meeting

  7. Photonic crystal Fano lasers and Fano switches

    DEFF Research Database (Denmark)

    Mørk, Jesper; Yu, Yi; Bekele, Dagmawi Alemayehu

    2017-01-01

    We show that Fano resonances can be realized in photonic crystal membrane structures by coupling line-defect waveguides and point-defect nanocavities. The Fano resonance can be exploited to realize optical switches with very small switching energy, as well as Fano lasers, that can generate short...

  8. High-explosive driven crowbar switch

    International Nuclear Information System (INIS)

    Dike, R.S.; Kewish, R.W. Jr.

    1976-01-01

    The disclosure relates to a compact explosive driven switch for use as a low resistance, low inductance crowbar switch. A high-explosive charge extrudes a deformable conductive metallic plate through a polyethylene insulating layer to achieve a hard current contact with a supportive annular conductor

  9. Simulation of linear Switched Reluctance Motor drives

    OpenAIRE

    Garcia Amoros, Jordi; Blanqué Molina, Balduino; Andrada Gascón, Pedro

    2011-01-01

    This paper presents a simulation model of linear switched reluctance motor drives. A Matlab-Simulink environment coupled with finite element analysis is used to perform the simulations. Experimental and simulation results for a double sided linear switched motor drive prototype are reported and compared to verify the simulation model.

  10. Seismic switch for strong motion measurement

    Science.gov (United States)

    Harben, P.E.; Rodgers, P.W.; Ewert, D.W.

    1995-05-30

    A seismic switching device is described that has an input signal from an existing microseismic station seismometer and a signal from a strong motion measuring instrument. The seismic switch monitors the signal level of the strong motion instrument and passes the seismometer signal to the station data telemetry and recording systems. When the strong motion instrument signal level exceeds a user set threshold level, the seismometer signal is switched out and the strong motion signal is passed to the telemetry system. The amount of time the strong motion signal is passed before switching back to the seismometer signal is user controlled between 1 and 15 seconds. If the threshold level is exceeded during a switch time period, the length of time is extended from that instant by one user set time period. 11 figs.

  11. A Mechanical Switch Using Spectral Microshifts

    Science.gov (United States)

    Mitchell, Gordon L.; Saaski, Elric W.; Hartl, James C.

    1989-02-01

    Among the simplest fiber optic sensors, are those which operate in a binary fashion; they were the first sensor types to be developed. Early experiments with fiber bundles and shutters produced demonstrations of, for example, displacement sensors. Typical applications range from position sensing for aircraft landing gear to counting objects on a production line. Because they frequently replace electrical snap action switches, binary sensors are generally called optical switches. Optical switch applications account for a much larger market than the more complex analog measurements discussed in the balance of this volume. This paper presents an optical switch concept that uses a single fiber and is tolerant of back reflections. The sensor element is a low finesse Fabry-Perot pressure sensor which replaces the electrical contact in a conventional snap action switch.

  12. Switched-capacitor isolated LED driver

    Science.gov (United States)

    Sanders, Seth R.; Kline, Mitchell

    2016-03-22

    A switched-capacitor voltage converter which is particularly well-suited for receiving a line voltage from which to drive current through a series of light emitting diodes (LEDs). Input voltage is rectified in a multi-level rectifier network having switched capacitors in an ascending-bank configuration for passing voltages in uniform steps between zero volts up to full received voltage V.sub.DC. A regulator section, operating on V.sub.DC, comprises switched-capacitor stages of H-bridge switching and flying capacitors. A current controlled oscillator drives the states of the switched-capacitor stages and changes its frequency to maintain a constant current to the load. Embodiments are described for isolating the load from the mains, utilizing an LC tank circuit or a multi-primary-winding transformer.

  13. Implications of Sepedi/English code switching for ASR systems

    CSIR Research Space (South Africa)

    Modipa, TI

    2013-12-01

    Full Text Available Code switching (the process of switching from one language to another during a conversation) is a common phenomenon in multilingual environments. Where a minority and dominant language coincide, code switching from the minority language...

  14. Slowly switching between environments facilitates reverse evolution in small populations.

    Science.gov (United States)

    Tan, Longzhi; Gore, Jeff

    2012-10-01

    Natural populations must constantly adapt to ever-changing environmental conditions. A particularly interesting question is whether such adaptations can be reversed by returning the population to an ancestral environment. Such evolutionary reversals have been observed in both natural and laboratory populations. However, the factors that determine the reversibility of evolution are still under debate. The time scales of environmental change vary over a wide range, but little is known about how the rate of environmental change influences the reversibility of evolution. Here, we demonstrate computationally that slowly switching between environments increases the reversibility of evolution for small populations that are subject to only modest clonal interference. For small populations, slow switching reduces the mean number of mutations acquired in a new environment and also increases the probability of reverse evolution at each of these "genetic distances." As the population size increases, slow switching no longer reduces the genetic distance, thus decreasing the evolutionary reversibility. We confirm this effect using both a phenomenological model of clonal interference and also a Wright-Fisher stochastic simulation that incorporates genetic diversity. Our results suggest that the rate of environmental change is a key determinant of the reversibility of evolution, and provides testable hypotheses for experimental evolution. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  15. The physiological costs of prey switching reinforce foraging specialization.

    Science.gov (United States)

    Hooker, Oliver E; Van Leeuwen, Travis E; Adams, Colin E

    2017-05-01

    Sympatric speciation is thought to be strongly linked to resource specialization with alternative resource use acting as a fundamental agent driving divergence. However, sympatric speciation through niche expansion is dependent on foraging specialization being consistent over space and time. Standard metabolic rate is the minimal maintenance metabolic rate of an ectotherm in a post-absorptive and inactive state and can constitute a significant portion of an animal's energy budget; thus, standard metabolic rate and growth rate are two measures frequently used as an indication of the physiological performance of individuals. Physiological adaptations to a specific diet may increase the efficiency with which it is utilized, but may have an increased cost associated with switching diets, which may result in a reduced standard metabolic rate and growth rate. In this study, we use the diet specialization often seen in polymorphic Arctic charr (Salvelinus alpinus) populations to study the effects of different prey on standard metabolic rate and growth rate as well as the effects that early prey specialization may have on the ability to process other prey types efficiently. We found a significant effect of prey type on standard metabolic rate and growth rate. Furthermore, we found evidence of diet specialization with all fish maintaining a standard metabolic rate and growth rate lower than expected when fed on a diet different to which they were raised, possibly due to a maladaptation in digestion of alternative prey items. Our results show that early diet specialization may be reinforced by the elevated costs of prey switching, thus promoting the process of resource specialization during the incipient stages of sympatric divergence. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

  16. Fiscal deficits, exchange rate crises and inflation.

    NARCIS (Netherlands)

    van Wijnbergen, S.J.G.

    1991-01-01

    This article extends earlier work on unsustainable monetary policies by endogenizing the regime switch that ultimately restores sustainability. Within this framework we analyze exchange rate based stabilization programs and shows how constraints on Central Bank borrowing during an exchange crisis

  17. Dual-kind Q-switching of erbium fiber laser

    Energy Technology Data Exchange (ETDEWEB)

    Barmenkov, Yuri O., E-mail: yuri@cio.mx; Kir' yanov, Alexander V. [Centro de Investigaciones en Optica, Loma del Bosque 115, Col. Lomas del Campestre, 37150 Leon, Guanajuato (Mexico); Cruz, Jose L.; Andres, Miguel V. [Department of Applied Physics and Electromagnetism, University of Valencia, Dr. Moliner 50, Burjassot 46100 (Spain)

    2014-03-03

    Two different regimes of Q-switching in the same implementation of an actively Q-switched erbium-doped fiber laser are demonstrated. Depending on the active fiber length and repetition rate of an intracavity Q-cell (acousto-optic modulator), the laser operates either in the regime of common, rather long and low-power, pulses composed of several sub-pulses or in the one of very short and powerful stimulated Brillouin scattering-induced pulses. The basic physical reason of the laser system to oscillate in one of these two regimes is the existence or absence of CW narrow-line “bad-cavity” lasing in the intervals when the Q-cell is blocked.

  18. Performance analysis of switching based hybrid FSO/RF transmission

    KAUST Repository

    Usman, Muneer

    2014-09-01

    Hybrid free space optical (FSO)/ radio frequency (RF) systems have emerged as a promising solution for high data rate wireless back haul.We present and analyze a switching based transmission scheme for hybrid FSO/RF system. Specifically, either FSO or RF link will be active at a certain time instance, with FSO link enjoying a higher priority. Analytical expressions have been obtained for the outage probability, average bit error rate and ergodic capacity for the resulting system. Numerical examples are presented to compare the performance of the hybrid scheme with FSO only scenario.

  19. Comparison of strain generated in bone by "platform-switched" and "non-platform-switched" implants with straight and angulated abutments under vertical and angulated load: A finite element analysis study

    Directory of Open Access Journals (Sweden)

    Susan Paul

    2013-01-01

    Full Text Available Purpose: The aim of this study was to evaluate the microstrain exhibited by bone around immediately loaded, platform-switched, and non-platform-switched implants under vertical and angled loading using a finite element analysis (FEA and also to evaluate whether platform-switched implants evoke a better response than non-platform-switched implants on a mechanical basis. Materials and Methods: Three-dimensional finite element study was undertaken to model and analyze an immediate loaded situation. FEA was chosen for this study since it is useful in determining the stress and strain around the dental implant. Bone responses to vertical and angulated loads on straight and angulated abutments (platform-switched and non-platform-switched abutments were evaluated. Results: Non-platform-switched abutments tend to exhibit a lower tensile stress and compressive stress but higher microstrain value (conducive to higher chance of bone resorption than platform-switched abutments. Ideal bone remodeling values of microstrain (50-3000 μϵ were exhibited by platform-switched straight abutments under vertical load and angled load (with an abutment-implant diameter difference of 1 mm. Conclusion: In spite of the obvious advantages, the practice of immediate loading is limited due to apprehension associated with compromised bone response and a higher rate of bone loss around an immediately loaded implant. The mechanical basis for the concept of "platform switching" in immediately loaded situation is analyzed in this context. The results of this limited investigation indicated that the ideal values of microstrain (50-3000 microstrain can be exhibited by platform switching of dental implants (with an abutment-implant diameter difference of 1 mm and can be considered as a better alternative for prevention of crestal bone loss when compared to non-platform-switched implants.

  20. Design of all Optical Packet Switching Networks

    Directory of Open Access Journals (Sweden)

    Hussein T. Mouftah

    2002-06-01

    Full Text Available Optical switches and wavelength converters are recognized as two of the most important DWDM system components in future all-optical networks. Optical switches perform the key functions of flexible routing, reconfigurable optical cross-connect (OXC, network protection and restoration, etc. in optical networks. Wavelength Converters are used to shift one incoming wavelength to another outgoing wavelength when this needs to be done.  Always residing in optical switches, they can effectively alleviate the blocking probability and help solve contention happening at the output port of switches. The deployment of wavelength converters within optical switches provides robust routing, switching and network management in optical layer, which is critical to the emerging all-optical Internet. However, the high cost of wavelength converters at current stage of manufacturing technology has to be taken into consideration when we design node architectures for an optical network. Our research explores the efficiency of wavelength converters in a long-haul optical network at different degrees of traffic load by running a simulation. Then, we propose a new cost-effective way to optimally design wavelength-convertible switch so as to achieve higher network performance while still keeping the total network cost down. Meanwhile, the routing and wavelength assignment (RWA algorithm used in the research is designed to be a generic one for both large-scale and small-scale traffic. Removing the constraint on the traffic load makes the RWA more adaptive and robust. When this new RWA works in conjunction with a newly introduced concept of wavelength-convertible switches, we shall explore the impact of large-scale traffic on the role of wavelength converter so as to determine the method towards optimal use of wavelength convertible switches for all-optical networks.

  1. Switching from risperidone to olanzapine in a one-year, randomized, open-label effectiveness study of schizophrenia.

    Science.gov (United States)

    Faries, Douglas E; Ascher-Svanum, Haya; Nyhuis, Allen W; Kinon, Bruce J

    2008-05-01

    Switching medications is common in the treatment of schizophrenia. This study examines the effectiveness of olanzapine therapy following a clinically warranted switch from risperidone during treatment of patients with schizophrenia. This post-hoc analysis used data from the risperidone arm of a randomized, open-label, 1-year study of patients with schizophrenia. Study protocol permitted antipsychotic switching when clinically warranted, and outcomes were assessed with standard psychiatric measures. Statistical analyses assessed changes from pre- to post-medication switch and endpoint comparisons between patients switched from risperidone to olanzapine and patients continued on risperidone. Most patients who switched from risperidone switched to olanzapine (43/60; 71.7%). Average duration of risperidone treatment prior to switching was 86 days (mean modal dose 4.0 mg/day). Most switchers (86%) completed the 1-year study on olanzapine (average duration 241 days; mean modal dose 12.0 mg/day). Following switch to olanzapine, patients experienced significant improvements on clinical (Brief Psychiatric Rating Scale) and social (Quality of Life Inventory) parameters, with similar proportions of patients achieving remission status at endpoint compared with risperidone patients not requiring medication switch (41.9 vs. 35.5%). Mean weight gain for switchers was approximately 0.4 kg while on risperidone (average treatment duration < 3 months) and 2.4 kg on olanzapine (average treatment duration approximately 8 months). This study suggests that olanzapine is an effective treatment option for schizophrenia patients requiring a switch from risperidone. Given the small sample size and lack of a comparative group, one cannot determine if other medication options would have been as effective as the switch to olanzapine. Thus, further research is warranted.

  2. Comparison of switching control algorithms effective in restricting the switching in the neighborhood of the origin

    International Nuclear Information System (INIS)

    Joung, JinWook; Chung, Lan; Smyth, Andrew W

    2010-01-01

    The active interaction control (AIC) system consisting of a primary structure, an auxiliary structure and an interaction element was proposed to protect the primary structure against earthquakes and winds. The objective of the AIC system in reducing the responses of the primary structure is fulfilled by activating or deactivating the switching between the engagement and the disengagement of the primary and auxiliary structures through the interaction element. The status of the interaction element is controlled by switching control algorithms. The previously developed switching control algorithms require an excessive amount of switching, which is inefficient. In this paper, the excessive amount of switching is restricted by imposing an appropriately designed switching boundary region, where switching is prohibited, on pre-designed engagement–disengagement conditions. Two different approaches are used in designing the newly proposed AID-off and AID-off 2 algorithms. The AID-off 2 algorithm is designed to affect deactivated switching regions explicitly, unlike the AID-off algorithm, which follows the same procedure of designing the engagement–disengagement conditions of the previously developed algorithms, by using the current status of the AIC system. Both algorithms are shown to be effective in reducing the amount of switching times triggered from the previously developed AID algorithm under an appropriately selected control sampling period for different earthquakes, but the AID-off 2 algorithm outperforms the AID-off algorithm in reducing the number of switching times

  3. Organization of the channel-switching process in parallel computer systems based on a matrix optical switch

    Science.gov (United States)

    Golomidov, Y. V.; Li, S. K.; Popov, S. A.; Smolov, V. B.

    1986-01-01

    After a classification and analysis of electronic and optoelectronic switching devices, the design principles and structure of a matrix optical switch is described. The switching and pair-exclusion operations in this type of switch are examined, and a method for the optical switching of communication channels is elaborated. Finally, attention is given to the structural organization of a parallel computer system with a matrix optical switch.

  4. Preliminary results of the duodenal switch.

    Science.gov (United States)

    Baltasar, A; del Rio, J; Escrivá, C; Arlandis, F; Martínez, R; Serra, C

    1997-12-01

    The duodenal switch (DS), as a modification of the bilio-pancreatic diversion (BPD), is a 'complex' hybrid operation. Sixty patients were operated on during the last 3 years. Two patients died early (3.3%); two late deaths occurred at 4 and 7 months, one due to liver failure and the other due to malnutrition and refeeding syndrome (3.57%); three patients required conversions (5.3%). The two early deaths and all the patients who required conversions had a previous vertical banded gastroplasty. Eleven patients had minor liver abnormalities corrected with medications, and one patient had severe diarrhea for more than a year. Eleven female patients have iron deficiency anemia that requires parenteral supplementation. Mean percent excess weight loss was 86% at 2.5 years. The DS has been, in our experience, an unsafe operation with unacceptably high operative and postoperative mortality. The conversion rate is acceptable. Weight loss, quality of food intake and life have been excellent. Inadequate follow-up can be dangerous if patients fail to report for regular visits.

  5. Fault tolerant control for switched linear systems

    CERN Document Server

    Du, Dongsheng; Shi, Peng

    2015-01-01

    This book presents up-to-date research and novel methodologies on fault diagnosis and fault tolerant control for switched linear systems. It provides a unified yet neat framework of filtering, fault detection, fault diagnosis and fault tolerant control of switched systems. It can therefore serve as a useful textbook for senior and/or graduate students who are interested in knowing the state-of-the-art of filtering, fault detection, fault diagnosis and fault tolerant control areas, as well as recent advances in switched linear systems.  

  6. Consumer poaching, brand switching, and price transparency

    DEFF Research Database (Denmark)

    Schultz, Christian

    2014-01-01

    This paper addresses price transparency on the consumer side in markets with behavioral price discrimination which feature welfare reducing brand switching. When long-term contracts are not available, an increase in transparency intensifies competition, lowers prices and profits, reduces brand...... switching and benefits consumers and welfare. With long-term contracts, an increase in transparency reduces the use of long-term contracts, leading to more brand switching and a welfare loss. Otherwise, the results are the same as without long-term contracts....

  7. Design of a switched reluctance generator

    Energy Technology Data Exchange (ETDEWEB)

    Heese, T.; Pyrhoenen, J.

    1996-12-31

    This report presents the design of a low voltage switched reluctance generator for variable speed applications showing the design of its construction and commutation unit. For the realisation of the control system the control strategy is presented. The principle and the theory of switched reluctance generators are described in this context. Also an overview of existing generator technology for these applications is given. The results gained suggest that switched reluctance machines can also advantageously be used as generators if the generating operation is considered within the design process. Compared with the existing technology a higher output power and efficiency is reached over the whole speed range. (orig.)

  8. Electrically switched cesium ion exchange

    International Nuclear Information System (INIS)

    Lilga, M.A.; Orth, R.J.; Sukamto, J.P.H.; Schwartz, D.T.; Haight, S.M.; Genders, J.D.

    1997-04-01

    Electrically Switched Ion Exchange (ESIX) is a separation technology being developed as an alternative to conventional ion exchange for removing radionuclides from high-level waste. The ESIX technology, which combines ion exchange and electrochemistry, is geared toward producing electroactive films that are highly selective, regenerable, and long lasting. During the process, ion uptake and elution are controlled directly by modulating the potential of an ion exchange film that has been electrochemically deposited onto a high surface area electrode. This method adds little sodium to the waste stream and minimizes the secondary wastes associated with traditional ion exchange techniques. Development of the ESIX process is well underway for cesium removal using ferrocyanides as the electroactive films. Films having selectivity for perrhenate (a pertechnetate surrogate) over nitrate also have been deposited and tested. A case study for the KE Basin on the Hanford Site was conducted based on the results of the development testing. Engineering design baseline parameters for film deposition, film regeneration, cesium loading, and cesium elution were used for developing a conceptual system. Order of magnitude cost estimates were developed to compare with conventional ion exchange. This case study demonstrated that KE Basin wastewater could be processed continuously with minimal secondary waste and reduced associated disposal costs, as well as lower capital and labor expenditures

  9. Switching on the Aire conditioner.

    Science.gov (United States)

    Matsumoto, Mitsuru

    2015-12-01

    Aire has been cloned as the gene responsible for a hereditary type of organ-specific autoimmune disease. Aire controls the expression of a wide array of tissue-restricted Ags by medullary thymic epithelial cells (mTECs), thereby leading to clonal deletion and Treg-cell production, and ultimately to the establishment of self-tolerance. However, relatively little is known about the mechanism responsible for the control of Aire expression itself. In this issue of the European Journal of Immunology, Haljasorg et al. [Eur. J. Immunol. 2015. 45: 3246-3256] have reported the presence of an enhancer element for Aire that binds with NF-κB components downstream of the TNF receptor family member, RANK (receptor activator of NF-κB). The results suggest that RANK has a dual mode of action in Aire expression: one involving the promotion of mTEC differentiation and the other involving activation of the molecular switch for Aire within mature mTECs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Modeling and simulation of GaN step-up power switched capacitor converter

    Science.gov (United States)

    Alateeq, Ayoob S.; Almalaq, Yasser A.; Matin, Mohammad A.

    2017-08-01

    This paper discusses a proposed DC-DC switched capacitor converter for low voltage electronic products. The proposed converter is a two-level power switched capacitor (PSC) which is a boost converter. The suitability to convert a voltage into four times higher than its input is one of the converter's objectives. Because of the proposed two-level PSC consist of eight switches and five capacitors, it occupies a small area of the electronic products. The eight switches were selected to be GaN transistors to maintain the efficiency at high rated power or high temperatures. The LTSpice simulator was used to test the proposed model. Since the design contains semiconductor elements such (GaN transistor), then 10% error is a reasonable variance between the mathematical and simulation results.

  11. Dual branch transmit switch-and-stay diversity for underlay cognitive networks

    KAUST Repository

    Sayed, Mostafa M.

    2011-05-01

    In this paper, we study applying dual branch transmit switch-and-stay combining (SSC) technique for underlay cognitive radio (UCR) networks. In UCR, the secondary user is allowed to share the spectrum with the primary (licensed) user under the condition that interference at the primary receiver is below a predetermined threshold. Assuming binary phaseshift keying (BPSK) modulation and Rayleigh fading channels, we develop a closed form expression for the average bit error rate (BER) of the secondary link as a function of the switching threshold. We then find a closed form expression for the optimal switching threshold in the sense of minimizing the average BER. For the sake of comparison we derive an expression for the average BER of the dual branch transmit selection combining (SC) technique. We finally investigate the effect of correlation between secondary and interference channels on the average BER and the associated optimal switching threshold. © 2011 IEEE.

  12. Information Switching Processor (ISP) contention analysis and control

    Science.gov (United States)

    Inukai, Thomas

    1995-01-01

    In designing a satellite system with on-board processing, the selection of a switching architecture is often critical. The on-board switching function can be implemented by circuit switching or packet switching. Destination-directed packet switching has several attractive features, such as self-routing without on-board switch reconfiguration, no switch control memory requirement, efficient bandwidth utilization for packet switched traffic, and accommodation of circuit switched traffic. Destination-directed packet switching, however, has two potential concerns: (1) contention and (2) congestion. And this report specifically deals with the first problem. It includes a description and analysis of various self-routing switch structures, the nature of contention problems, and contention and resolution techniques.

  13. Efficient in-band diode-pumped Q-switched solid state laser for methane detection, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop an efficient, tunable Q-switched SSL operating at a wavelength of 1651 nm with pulse energy >1 mJ at 2000 Hz repetition rate with in-band...

  14. Robust dynamic output feedback control for switched polytopic systems under asynchronous switching

    Directory of Open Access Journals (Sweden)

    Yang Tingting

    2015-08-01

    Full Text Available The robust controller design problem for switched polytopic systems under asynchronous switching is addressed. These systems exist in many aviation applications, such as dynamical systems involving rapid variations. A switched polytopic system is established to describe the highly maneuverable technology vehicle within the full flight envelope and a robust dynamic output feedback control method is designed for the switched polytopic system. Combining the Lyapunov-like function method and the average dwell time method, a sufficient condition is derived for the switched polytopic system with asynchronous switching and data dropout to be globally, uniformly and asymptotically stable in terms of linear matrix inequality. The robust dynamic output feedback controller is then applied to the highly maneuverable technology vehicle to illustrate the effectiveness of the proposed approach. The simulation results show that the angle of attack tracking performance is acceptable over the time history and the control surface responses are all satisfying along the full flight trajectory.

  15. Instability in time-delayed switched systems induced by fast and random switching

    Science.gov (United States)

    Guo, Yao; Lin, Wei; Chen, Yuming; Wu, Jianhong

    2017-07-01

    In this paper, we consider a switched system comprising finitely or infinitely many subsystems described by linear time-delayed differential equations and a rule that orchestrates the system switching randomly among these subsystems, where the switching times are also randomly chosen. We first construct a counterintuitive example where even though all the time-delayed subsystems are exponentially stable, the behaviors of the randomly switched system change from stable dynamics to unstable dynamics with a decrease of the dwell time. Then by using the theories of stochastic processes and delay differential equations, we present a general result on when this fast and random switching induced instability should occur and we extend this to the case of nonlinear time-delayed switched systems as well.

  16. Construction of large scale switch matrix by interconnecting integrated optical switch chips with EDFAs

    Science.gov (United States)

    Liao, Mingle; Wu, Baojian; Hou, Jianhong; Qiu, Kun

    2018-03-01

    Large scale optical switches are essential components in optical communication network. We aim to build up a large scale optical switch matrix by the interconnection of silicon-based optical switch chips using 3-stage CLOS structure, where EDFAs are needed to compensate for the insertion loss of the chips. The optical signal-to-noise ratio (OSNR) performance of the resulting large scale optical switch matrix is investigated for TE-mode light and the experimental results are in agreement with the theoretical analysis. We build up a 64 ×64 switch matrix by use of 16 ×16 optical switch chips and the OSNR and receiver sensibility can respectively be improved by 0.6 dB and 0.2 dB by optimizing the gain configuration of the EDFAs.

  17. Q-switching of a high-power solid-state laser by a fast scanning Fabry-Perot interferometer

    International Nuclear Information System (INIS)

    Baburin, N V; Borozdov, Yu V; Danileiko, Yu K; Denker, B I; Ivanov, A D; Osiko, Vyacheslav V; Sverchkov, S E; Sidorin, A V; Chikov, V A; Ifflander, R; Hack, R; Kertesz, I; Kroo, N

    1998-01-01

    An investigation was made of the suitability of a Q-switch, based on a piezoelectrically scanned short-base Fabry-Perot interferometer, for an Nd 3+ :YAG laser with an average output radiation power up to 2 kW. The proposed switch made it possible to generate of giant pulses of 60 - 300 ns duration at a repetition rate of 20 - 100 kHz. Throughout the investigated range of the pulse repetition rates the average power was at least equal to that obtained by cw lasing. Special requirements to be satisfied by the interferometer, essential for efficient Q-switching, were considered. (control of laser radiation parameters)

  18. Granular acoustic switches and logic elements

    Science.gov (United States)

    Li, Feng; Anzel, Paul; Yang, Jinkyu; Kevrekidis, Panayotis G.; Daraio, Chiara

    2014-10-01

    Electrical flow control devices are fundamental components in electrical appliances and computers; similarly, optical switches are essential in a number of communication, computation and quantum information-processing applications. An acoustic counterpart would use an acoustic (mechanical) signal to control the mechanical energy flow through a solid material. Although earlier research has demonstrated acoustic diodes or circulators, no acoustic switches with wide operational frequency ranges and controllability have been realized. Here we propose and demonstrate an acoustic switch based on a driven chain of spherical particles with a nonlinear contact force. We experimentally and numerically verify that this switching mechanism stems from a combination of nonlinearity and bandgap effects. We also realize the OR and AND acoustic logic elements by exploiting the nonlinear dynamical effects of the granular chain. We anticipate these results to enable the creation of novel acoustic devices for the control of mechanical energy flow in high-performance ultrasonic devices.

  19. Blood and Books: Performing Code Switching

    Directory of Open Access Journals (Sweden)

    Jeff Friedman

    2008-05-01

    Full Text Available Code switching is a linguistic term that identifies ways individuals use communication modes and registers to negotiate difference in social relations. This essay suggests that arts-based inquiry, in the form of choreography and performance, provides a suitable and efficacious location within which both verbal and nonverbal channels of code switching can be investigated. Blood and Books, a case study of dance choreography within the context of post-colonial Maori performance in Aotearoa/New Zealand, is described and analyzed for its performance of code switching. The essay is framed by a discussion of how arts-based research within tertiary higher education requires careful negotiation in the form of code switching, as performed by the author's reflexive use of vernacular and formal registers in the essay. URN: urn:nbn:de:0114-fqs0802462

  20. Active plasmonics in WDM traffic switching applications

    DEFF Research Database (Denmark)

    Papaioannou, S.; Kalavrouziotis, D.; Vyrsokinos, K.

    2012-01-01

    With metal stripes being intrinsic components of plasmonic waveguides, plasmonics provides a "naturally" energy-efficient platform for merging broadband optical links with intelligent electronic processing, instigating a great promise for low-power and small-footprint active functional circuitry....... The first active Dielectric-Loaded Surface Plasmon Polariton (DLSPP) thermo-optic (TO) switches with successful performance in single-channel 10 Gb/s data traffic environments have led the inroad towards bringing low-power active plasmonics in practical traffic applications. In this article, we introduce...... active plasmonics into Wavelength Division Multiplexed (WDM) switching applications, using the smallest TO DLSPP-based Mach-Zehnder interferometric switch reported so far and showing its successful performance in 4310 Gb/s low-power and fast switching operation. The demonstration of the WDM...

  1. Bistable fluidic valve is electrically switched

    Science.gov (United States)

    Fiet, O.; Salvinski, R. J.

    1970-01-01

    Bistable control valve is selectively switched by direct application of an electrical field to divert fluid from one output channel to another. Valve is inexpensive, has no moving parts, and operates on fluids which are relatively poor electrical conductors.

  2. Multi-planed unified switching topologies

    Science.gov (United States)

    Chen, Dong; Heidelberger, Philip; Sugawara, Yutaka

    2017-07-04

    An apparatus and method for extending the scalability and improving the partitionability of networks that contain all-to-all links for transporting packet traffic from a source endpoint to a destination endpoint with low per-endpoint (per-server) cost and a small number of hops. An all-to-all wiring in the baseline topology is decomposed into smaller all-to-all components in which each smaller all-to-all connection is replaced with star topology by using global switches. Stacking multiple copies of the star topology baseline network creates a multi-planed switching topology for transporting packet traffic. Point-to-point unified stacking method using global switch wiring methods connects multiple planes of a baseline topology by using the global switches to create a large network size with a low number of hops, i.e., low network latency. Grouped unified stacking method increases the scalability (network size) of a stacked topology.

  3. Information, switching costs, and consumer choice:

    DEFF Research Database (Denmark)

    Anell, Anders; Dietrichson, Jens; Maria Ellegård, Lina

    . Such improvements are contingent on consumers having access to comparative information about providers and acting on this information when making their choice. However, in the presence of information frictions and switching costs, consumers may have limited ability to find suitable providers. We use two large......-scale randomized eld experiments in primary health care to examine if the choice of provider is affected when consumers receive comparative information by postal mail and small costs associated with switching are reduced. The first experiment targeted a subset of the general population in the Swedish region Skåne......, and the second targeted new residents in the region, who should have less prior information and lower switching costs. In both cases, the propensity to switch provider increased significantly after the intervention. The effects were larger for new residents than for the general population, and were driven...

  4. Analysis of Switched-Rigid Floating Oscillator

    Directory of Open Access Journals (Sweden)

    Prabhakar R. Marur

    2009-01-01

    Full Text Available In explicit finite element simulations, a technique called deformable-to-rigid (D2R switching is used routinely to reduce the computation time. Using the D2R option, the deformable parts in the model can be switched to rigid and reverted back to deformable when needed during the analysis. The time of activation of D2R however influences the overall dynamics of the system being analyzed. In this paper, a theoretical basis for the selection of time of rigid switching based on system energy is established. A floating oscillator problem is investigated for this purpose and closed-form analytical expressions are derived for different phases in rigid switching. The analytical expressions are validated by comparing the theoretical results with numerical computations.

  5. The allosteric switching mechanism in bacteriophage MS2

    Science.gov (United States)

    Perkett, Matthew R.; Mirijanian, Dina T.; Hagan, Michael F.

    2016-07-01

    We use all-atom simulations to elucidate the mechanisms underlying conformational switching and allostery within the coat protein of the bacteriophage MS2. Assembly of most icosahedral virus capsids requires that the capsid protein adopts different conformations at precise locations within the capsid. It has been shown that a 19 nucleotide stem loop (TR) from the MS2 genome acts as an allosteric effector, guiding conformational switching of the coat protein during capsid assembly. Since the principal conformational changes occur far from the TR binding site, it is important to understand the molecular mechanism underlying this allosteric communication. To this end, we use all-atom simulations with explicit water combined with a path sampling technique to sample the MS2 coat protein conformational transition, in the presence and absence of TR-binding. The calculations find that TR binding strongly alters the transition free energy profile, leading to a switch in the favored conformation. We discuss changes in molecular interactions responsible for this shift. We then identify networks of amino acids with correlated motions to reveal the mechanism by which effects of TR binding span the protein. We find that TR binding strongly affects residues located at the 5-fold and quasi-sixfold interfaces in the assembled capsid, suggesting a mechanism by which the TR binding could direct formation of the native capsid geometry. The analysis predicts amino acids whose substitution by mutagenesis could alter populations of the conformational substates or their transition rates.

  6. The allosteric switching mechanism in bacteriophage MS2

    Energy Technology Data Exchange (ETDEWEB)

    Perkett, Matthew R.; Mirijanian, Dina T.; Hagan, Michael F., E-mail: hagan@brandeis.edu [Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02474 (United States)

    2016-07-21

    We use all-atom simulations to elucidate the mechanisms underlying conformational switching and allostery within the coat protein of the bacteriophage MS2. Assembly of most icosahedral virus capsids requires that the capsid protein adopts different conformations at precise locations within the capsid. It has been shown that a 19 nucleotide stem loop (TR) from the MS2 genome acts as an allosteric effector, guiding conformational switching of the coat protein during capsid assembly. Since the principal conformational changes occur far from the TR binding site, it is important to understand the molecular mechanism underlying this allosteric communication. To this end, we use all-atom simulations with explicit water combined with a path sampling technique to sample the MS2 coat protein conformational transition, in the presence and absence of TR-binding. The calculations find that TR binding strongly alters the transition free energy profile, leading to a switch in the favored conformation. We discuss changes in molecular interactions responsible for this shift. We then identify networks of amino acids with correlated motions to reveal the mechanism by which effects of TR binding span the protein. We find that TR binding strongly affects residues located at the 5-fold and quasi-sixfold interfaces in the assembled capsid, suggesting a mechanism by which the TR binding could direct formation of the native capsid geometry. The analysis predicts amino acids whose substitution by mutagenesis could alter populations of the conformational substates or their transition rates.

  7. The Robustness of Stochastic Switching Networks

    OpenAIRE

    Loh, Po-Ling; Zhou, Hongchao; Bruck, Jehoshua

    2009-01-01

    Many natural systems, including chemical and biological systems, can be modeled using stochastic switching circuits. These circuits consist of stochastic switches, called pswitches, which operate with a fixed probability of being open or closed. We study the effect caused by introducing an error of size ∈ to each pswitch in a stochastic circuit. We analyze two constructions – simple series-parallel and general series-parallel circuits – and prove that simple series-parallel circuits are robus...

  8. Automatic Control System Switching Roadway Lighting

    OpenAIRE

    Agus Trimuji Susilo; Lingga Hermanto Drs. MM

    2002-01-01

    Lack of attention to the information officer street lights, cause is not exactly the timewhen the blame lights street lighting street - the street in this city protocol. And whenit was already dark, the lights had not lit, so it can harm the users of the road. Werecommend that when it got bright lights - the lights switched off late, so muchelectricity is wasted with nothing - nothing.Given the problems above, the automatic switching is required that can control all thelights - the existing l...

  9. Optical waveguide switch through magnetic reflectance wall

    Science.gov (United States)

    Fang, Yuntuan; Ni, Zhiyao; Yang, Lixia

    2016-04-01

    We propose a new design to achieve optical waveguide switch. We construct a photonic crystal waveguide with one yttrium iron garnet (YIG) rod array on the two sides of the waveguide. Through the mode analysis, we find in special frequency range a few YIG rods under magnetic field can form the magnetic reflectance wall that blocks the light flow. Removing the magnetic field will delete the reflection wall and let the blocked light to be switched on.

  10. Ring oscillator switching noise under NBTI wearout

    OpenAIRE

    Fernández García, Raúl; Gil Galí, Ignacio; Ruiz, José María; Morata Cariñena, Marta

    2011-01-01

    In this paper the switching noise of a CMOS ring oscillator has been analysed when their pFETs are subjected to negative bias temperature instability (NBTI). The impact of pFET under NBTI has been experimentally quantified whereas CMOS ring oscillator frequency and the switching noise has been analysed by means of electrical full-model simulation. The results show that the impact on the electromagnetic compatibility behaviour increases with NBTI wearout. Peer Reviewed

  11. Portfolio Selection with Jumps under Regime Switching

    Directory of Open Access Journals (Sweden)

    Lin Zhao

    2010-01-01

    Full Text Available We investigate a continuous-time version of the mean-variance portfolio selection model with jumps under regime switching. The portfolio selection is proposed and analyzed for a market consisting of one bank account and multiple stocks. The random regime switching is assumed to be independent of the underlying Brownian motion and jump processes. A Markov chain modulated diffusion formulation is employed to model the problem.

  12. Lasers for switched-power linacs

    International Nuclear Information System (INIS)

    Bigio, I.J.

    1988-01-01

    Laser-switched power surges for particle accelerators, just as with direct laser-driven accelerator schemes, place unique demands on the specifications of the invoked laser systems. We review the laser requirements for switched power sources of the types described in other chapters of this volume. The relative advantages and disadvantages of selected lasers are listed, and the appropriateness and scalability of existing technology is discussed. 4 refs., 2 figs., 2 tabs

  13. New pulse modulator with low switching frequency

    Directory of Open Access Journals (Sweden)

    Golub V. S.

    2014-12-01

    Full Text Available The author presents an integrating pulse modulator (analog signal converter with the pulse frequency and duration modulation similar to sigma-delta modulation (with low switching frequency, without quantization. The modulator is characterized by the absence of the quantization noise inherent in sigma-delta modulator, and a low switching frequency, unlike the pulse-frequency modulator. The modulator is recommended, in particular, to convert signals at the input of the class D power amplifier.

  14. On The Snubber Influence To The Switching And Conduction Losses In A Converter Using Switched Capacitor

    Directory of Open Access Journals (Sweden)

    Viorel DUGAN

    2002-12-01

    Full Text Available The paper deals to design and to compute the snubber parameters influence on the switching and conduction losses of the transistors (IGBT used as bidirectional switches in a converter with switched capacitor. The converter was modelled with difference equations, and the transistors during turn-on and turn-off processes were simulated by dynamically varying resistance models. The energy loss per switching, commutation time, the variation of the transistor voltage etc. and the influence of snubber parameters in each of these cases are shown in the context of a converter used as a 50Hz reactive power controller unit

  15. Hybrid Optical Switching for Data Center Networks

    Directory of Open Access Journals (Sweden)

    Matteo Fiorani

    2014-01-01

    Full Text Available Current data centers networks rely on electronic switching and point-to-point interconnects. When considering future data center requirements, these solutions will raise issues in terms of flexibility, scalability, performance, and energy consumption. For this reason several optical switched interconnects, which make use of optical switches and wavelength division multiplexing (WDM, have been recently proposed. However, the solutions proposed so far suffer from low flexibility and are not able to provide service differentiation. In this paper we introduce a novel data center network based on hybrid optical switching (HOS. HOS combines optical circuit, burst, and packet switching on the same network. In this way different data center applications can be mapped to the optical transport mechanism that best suits their traffic characteristics. Furthermore, the proposed HOS network achieves high transmission efficiency and reduced energy consumption by using two parallel optical switches. We consider the architectures of both a traditional data center network and the proposed HOS network and present a combined analytical and simulation approach for their performance and energy consumption evaluation. We demonstrate that the proposed HOS data center network achieves high performance and flexibility while considerably reducing the energy consumption of current solutions.

  16. A Precise Temperature-Responsive Bistable Switch Controlling Yersinia Virulence.

    Science.gov (United States)

    Nuss, Aaron Mischa; Schuster, Franziska; Roselius, Louisa; Klein, Johannes; Bücker, René; Herbst, Katharina; Heroven, Ann Kathrin; Pisano, Fabio; Wittmann, Christoph; Münch, Richard; Müller, Johannes; Jahn, Dieter; Dersch, Petra

    2016-12-01

    Different biomolecules have been identified in bacterial pathogens that sense changes in temperature and trigger expression of virulence programs upon host entry. However, the dynamics and quantitative outcome of this response in individual cells of a population, and how this influences pathogenicity are unknown. Here, we address these questions using a thermosensing virulence regulator of an intestinal pathogen (RovA of Yersinia pseudotuberculosis) as a model. We reveal that this regulator is part of a novel thermoresponsive bistable switch, which leads to high- and low-invasive subpopulations within a narrow temperature range. The temperature range in which bistability is observed is defined by the degradation and synthesis rate of the regulator, and is further adjustable via a nutrient-responsive regulator. The thermoresponsive switch is also characterized by a hysteretic behavior in which activation and deactivation occurred on vastly different time scales. Mathematical modeling accurately mirrored the experimental behavior and predicted that the thermoresponsiveness of this sophisticated bistable switch is mainly determined by the thermo-triggered increase of RovA proteolysis. We further observed RovA ON and OFF subpopulations of Y. pseudotuberculosis in the Peyer's patches and caecum of infected mice, and that changes in the RovA ON/OFF cell ratio reduce tissue colonization and overall virulence. This points to a bet-hedging strategy in which the thermoresponsive bistable switch plays a key role in adapting the bacteria to the fluctuating conditions encountered as they pass through the host's intestinal epithelium and suggests novel strategies for the development of antimicrobial therapies.

  17. A Precise Temperature-Responsive Bistable Switch Controlling Yersinia Virulence.

    Directory of Open Access Journals (Sweden)

    Aaron Mischa Nuss

    2016-12-01

    Full Text Available Different biomolecules have been identified in bacterial pathogens that sense changes in temperature and trigger expression of virulence programs upon host entry. However, the dynamics and quantitative outcome of this response in individual cells of a population, and how this influences pathogenicity are unknown. Here, we address these questions using a thermosensing virulence regulator of an intestinal pathogen (RovA of Yersinia pseudotuberculosis as a model. We reveal that this regulator is part of a novel thermoresponsive bistable switch, which leads to high- and low-invasive subpopulations within a narrow temperature range. The temperature range in which bistability is observed is defined by the degradation and synthesis rate of the regulator, and is further adjustable via a nutrient-responsive regulator. The thermoresponsive switch is also characterized by a hysteretic behavior in which activation and deactivation occurred on vastly different time scales. Mathematical modeling accurately mirrored the experimental behavior and predicted that the thermoresponsiveness of this sophisticated bistable switch is mainly determined by the thermo-triggered increase of RovA proteolysis. We further observed RovA ON and OFF subpopulations of Y. pseudotuberculosis in the Peyer's patches and caecum of infected mice, and that changes in the RovA ON/OFF cell ratio reduce tissue colonization and overall virulence. This points to a bet-hedging strategy in which the thermoresponsive bistable switch plays a key role in adapting the bacteria to the fluctuating conditions encountered as they pass through the host's intestinal epithelium and suggests novel strategies for the development of antimicrobial therapies.

  18. Fast and flexible selection with a single switch.

    Directory of Open Access Journals (Sweden)

    Tamara Broderick

    Full Text Available Selection methods that require only a single-switch input, such as a button click or blink, are potentially useful for individuals with motor impairments, mobile technology users, and individuals wishing to transmit information securely. We present a single-switch selection method, "Nomon," that is general and efficient. Existing single-switch selection methods require selectable options to be arranged in ways that limit potential applications. By contrast, traditional operating systems, web browsers, and free-form applications (such as drawing place options at arbitrary points on the screen. Nomon, however, has the flexibility to select any point on a screen. Nomon adapts automatically to an individual's clicking ability; it allows a person who clicks precisely to make a selection quickly and allows a person who clicks imprecisely more time to make a selection without error. Nomon reaps gains in information rate by allowing the specification of beliefs (priors about option selection probabilities and by avoiding tree-based selection schemes in favor of direct (posterior inference. We have developed both a Nomon-based writing application and a drawing application. To evaluate Nomon's performance, we compared the writing application with a popular existing method for single-switch writing (row-column scanning. Novice users wrote 35% faster with the Nomon interface than with the scanning interface. An experienced user (author TB, with 10 hours practice wrote at speeds of 9.3 words per minute with Nomon, using 1.2 clicks per character and making no errors in the final text.

  19. Pseudo-spark switch (PSS) characteristics under different operation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hamad, B. H., E-mail: dr.bassmahussain@gmail.com; Ahmad, A. K., E-mail: ahmad.kamal@sc.nahrainuniv.edu.iq [College of Science, Al Nahrain University, Jadria, Baghdad (Iraq); Lateef, K. H., E-mail: kamalhlatif@yahoo.com [Ministry of Science and Technology, Jadria, Baghdad (Iraq)

    2016-08-15

    The present paper concentrates on the characteristics of the pseudospark switch (PSS) designed in a previous work. The special characteristics of PSS make it a replacement for other high voltage switches such as thyratrons and ordinary high-pressure spark gaps. PSS is characterized by short rise time and small jitter time. The pseudo park chamber consists of two hollow cylindrical electrodes made of a stainless steel material (type 306L) separated by an insulator. The insulator used in our design is a glazed ceramic 70 mm in diameter and 3.5 mm in thickness. A PSS with an anode voltage of 29.2 kV, and a current of 3.6 kA and 11 ns rise time was achieved and used successfully at a repetition rate of about 2.2 kHz. A simple trigger circuit designed, built, and used effectively reaching more than 1.56 kV trigger pulse which is sufficient to ignite the argon gas inside the cathode to cause a breakdown. A non-inductive dummy load is designed to be a new technique to find the accurate value of the PSS inductance. A jitter time of ±10 ns pulses is observed to occur in a reliable manner for more than 6 h of continuous operation. In this research, the important parameters of this switch like rise time, peak current, and anode voltage were studied at various values of charging capacitance. The lifetime of this system is depending on the kind of the electrode material and on the type of insulation material in the main gap of the pseudospark switch.

  20. Addendum to "Switching effect and the metal-insulator transition in electric field" by A.L. Pergament et al. [J. Phys. Chem. Solids 71 (2010) 874

    Science.gov (United States)

    Pergament, A. L.; Velichko, A. A.; Stefanovich, G. B.

    2015-02-01

    In the paper mentioned above we reported on the switching mechanism in vanadium dioxide which was shown to be based on the electronically-induced Mott insulator-to-metal transition occurring in conditions of the non-equilibrium carrier density excess in the applied electric field, and the proposed model involved the dependence of the carrier density n on electric field (the Poole-Frenkel effect), as well as the dependence of the critical electric field on n. The data on the n(T) dependence were obtained on the assumption of a temperature-independent carrier mobility μ, and the problem of n reduction at lower temperatures was not fully understood. In this Letter we revisit this problem in the light of some recent data on the μ(T) dependence for VO2. It is shown that the adjusted values of n, taking into account this μ(T), correspond to the Mott critical density within an order of magnitude.

  1. High-voltage high-current triggering vacuum switch

    International Nuclear Information System (INIS)

    Alferov, D.F.; Bunin, R.A.; Evsin, D.V.; Sidorov, V.A.

    2012-01-01

    Experimental investigations of switching and breaking capacities of the new high current triggered vacuum switch (TVS) are carried out at various parameters of discharge current. It has been shown that the high current triggered vacuum switch TVS can switch repeatedly a current from units up to ten kiloampers with duration up to ten millisecond [ru

  2. 49 CFR 236.342 - Switch circuit controller.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Switch circuit controller. 236.342 Section 236.342 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Instructions § 236.342 Switch circuit controller. Switch circuit controller connected at the point to switch...

  3. A new Zero-Voltage-Transition PWM switching cell

    Energy Technology Data Exchange (ETDEWEB)

    Grigore, V. [Electronics and Telecommunications Faculty `Politebuica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics

    1997-12-31

    In this paper a new Zero-Voltage-Transition (ZVT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus an auxiliary circuit (consisting of one active switch and some reactive components). The auxiliary circuit is inactive during the ON and OFF intervals of the switches in the normal PWM switch. However, the transitions between the two states are controlled by the auxiliary circuit. Prior to turn-on, the voltage across the active switch in the PWM cell is forced to zero, thus the turn-on losses of the active switch are practically eliminated. At turn-off the auxiliary circuit behaves like a non-dissipative passive snubber reducing the turn-off losses to a great extent. Zero-Voltage-Transition switching technique almost eliminates switching losses. The active switch operates under ZVT conditions, the passive switch (diode) has a controlled reverse recovery, and the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 6 refs.

  4. What makes the lac-pathway switch: identifying the fluctuations that trigger phenotype switching in gene regulatory systems.

    Science.gov (United States)

    Bhogale, Prasanna M; Sorg, Robin A; Veening, Jan-Willem; Berg, Johannes

    2014-10-01

    Multistable gene regulatory systems sustain different levels of gene expression under identical external conditions. Such multistability is used to encode phenotypic states in processes including nutrient uptake and persistence in bacteria, fate selection in viral infection, cell-cycle control and development. Stochastic switching between different phenotypes can occur as the result of random fluctuations in molecular copy numbers of mRNA and proteins arising in transcription, translation, transport and binding. However, which component of a pathway triggers such a transition is generally not known. By linking single-cell experiments on the lactose-uptake pathway in E. coli to molecular simulations, we devise a general method to pinpoint the particular fluctuation driving phenotype switching and apply this method to the transition between the uninduced and induced states of the lac-genes. We find that the transition to the induced state is not caused only by the single event of lac-repressor unbinding, but depends crucially on the time period over which the repressor remains unbound from the lac-operon. We confirm this notion in strains with a high expression level of the lac-repressor (leading to shorter periods over which the lac-operon remains unbound), which show a reduced switching rate. Our techniques apply to multistable gene regulatory systems in general and allow to identify the molecular mechanisms behind stochastic transitions in gene regulatory circuits. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  5. CONTROL OF BOUNCING IN RF MEMS SWITCHES USING DOUBLE ELECTRODE

    KAUST Repository

    Abdul Rahim, Farhan

    2014-05-01

    MEMS based mechanical switches are seen to be the likely replacements for CMOS based switches due to the several advantages that these mechanical switches have over CMOS switches. Mechanical switches can be used in systems under extreme conditions and also provide more reliability and cause less power loss. A major problem with mechanical switches is bouncing. Bouncing is an undesirable characteristic which increases the switching time and causes damage to the switch structure affecting the overall switch life. This thesis proposes a new switch design that may be used to mitigate bouncing by using two voltage sources using a double electrode configuration. The effect of many switch’s tunable parameters is also discussed and an effective tuning technique is also provided. The results are compared to the current control schemes in literature and show that the double electrode scheme is a viable control option.

  6. Analytical pricing formulas for hybrid variance swaps with regime-switching

    Science.gov (United States)

    Roslan, Teh Raihana Nazirah; Cao, Jiling; Zhang, Wenjun

    2017-11-01

    The problem of pricing discretely-sampled variance swaps under stochastic volatility, stochastic interest rate and regime-switching is being considered in this paper. An extension of the Heston stochastic volatility model structure is done by adding the Cox-Ingersoll-Ross (CIR) stochastic interest rate model. In addition, the parameters of the model are permitted to have transitions following a Markov chain process which is continuous and discoverable. This hybrid model can be used to illustrate certain macroeconomic conditions, for example the changing phases of business stages. The outcome of our regime-switching hybrid model is presented in terms of analytical pricing formulas for variance swaps.

  7. Temperature Independent Catalytic Two-Electron Reduction of Dioxygen by Ferrocenes with a Tris[2-(2-pyridyl)ethyl]amine-Copper(II) Catalyst in the Presence of Perchloric Acid

    Science.gov (United States)

    Das, Dipanwita; Lee, Yong-Min; Ohkubo, Kei; Nam, Wonwoo; Karlin, Kenneth D.; Fukuzumi, Shunichi

    2013-01-01

    Selective two-electron plus two-proton (2e−/2H+) reduction of O2 to hydrogen peroxide by ferrocene (Fc) or 1,1′-dimethylferrocene (Me2Fc) in the presence of perchloric acid is catalyzed efficiently by a mononuclear copper(II) complex, [CuII(tepa)]2+ {tepa = tris[2-(2-pyridyl)ethyl]amine} (1) in acetone. The E1/2 value for [CuII(tepa)]2+ as measured by cyclic voltammetry is 0.07 V vs Fc/Fc+ in acetone, being significantly positive, which makes it possible to use relatively weak one-electron reductants such as Fc and Me2Fc for the overall two-electron reduction of O2. Fast electron transfer from Fc or Me2Fc to 1 affords the corresponding CuI complex, [CuI(tepa)]+ (2), which reacts at low temperature (193 K) with O2, however only in presence of HClO4 to afford the hydroperoxo complex, [CuII(tepa)(OOH)]2+ (3). The detailed kinetic study on the homogeneous catalytic system reveals the rate-determining step to be the O2-binding process in the presence of HClO4 at lower temperature as well as at room temperature. The O2-binding kinetics in the presence of HClO4 were studied, demonstrating that the rate of formation of the hydroperoxo complex (3) as well as the overall catalytic reaction remained virtually the same with changing temperature. The apparent lack of an activation energy for the catalytic two-electron reduction of O2 is shown to result from the existence of a pre-equilibrium between 2 and O2 prior to the formation of the hydroperoxo complex 3. No further reduction of [CuII(tepa)(OOH)]2+ (3) by Fc or Me2Fc occurred, and instead 3 is protonated by HClO4 to yield H2O2 accompanied by regeneration of 1, thus completing the catalytic cycle for the two-electron reduction of O2 by Fc or Me2Fc. PMID:23394287

  8. Investigation of thyristor-based switches triggered in impact-ionization wave mode

    Science.gov (United States)

    Gusev, A. I.; Lyubutin, S. K.; Rukin, S. N.; Slovikovsky, B. G.; Tsyranov, S. N.

    2017-05-01

    An operation of the thyristor-based switches triggered in impact-ionization wave mode has been investigated. The thyristor switch contained two series connected tablet thyristors having a silicon wafer of 56 mm diameter. Applying across the switch a triggering pulse with a voltage rise rate dU/dt of over 1 kV/ns, the thyristors transition time to a conductive state was reduced to shorter than 1 ns. It is shown that the maximum amplitude of a no-failure current is increased with increasing dU/dt at the triggering stage. A possible mechanism of the dU/dt value effect on the thyristors breakdown current is discussed. Under a safety operation regime at dU/dt = 6 kV/ns (3 kV/ns per a single thyristor), the switch discharged 1-mF capacitor, which was charged to a voltage of 5 kV, to a resistive load of 18 mΩ. The following results were obtained: a peak current was 200 kA, an initial dI/dt was 58 kA/µs, a FWHM was 25 µs, and a switching efficiency was 0.97. It is shown also that a temperature of the silicon wafer is one of the main factors that affects on the thyristor switching process.

  9. The combination of positive and negative feedback loops confers exquisite flexibility to biochemical switches

    International Nuclear Information System (INIS)

    Pfeuty, Benjamin; Kaneko, Kunihiko

    2009-01-01

    A wide range of cellular processes require molecular regulatory pathways to convert a graded signal into a discrete response. One prevalent switching mechanism relies on the coexistence of two stable states (bistability) caused by positive feedback regulations. Intriguingly, positive feedback is often supplemented with negative feedback, raising the question of whether and how these two types of feedback can cooperate to control discrete cellular responses. To address this issue, we formulate a canonical model of a protein–protein interaction network and analyze the dynamics of a prototypical two-component circuit. The appropriate combination of negative and positive feedback loops can bring a bistable circuit close to the oscillatory regime. Notably, sharply activated negative feedback can give rise to a bistable regime wherein two stable fixed points coexist and may collide pairwise with two saddle points. This specific type of bistability is found to allow for separate and flexible control of switch-on and switch-off events, for example (i) to combine fast and reversible transitions, (ii) to enable transient switching responses and (iii) to display tunable noise-induced transition rates. Finally, we discuss the relevance of such bistable switching behavior, and the circuit topologies considered, to specific biological processes such as adaptive metabolic responses, stochastic fate decisions and cell-cycle transitions. Taken together, our results suggest an efficient mechanism by which positive and negative feedback loops cooperate to drive the flexible and multifaceted switching behaviors arising in biological systems

  10. Resistive switching in Ag-TiO{sub 2} contacts

    Energy Technology Data Exchange (ETDEWEB)

    Ghenzi, N., E-mail: ghenzi@cnea.gov.ar [Gerencia de Investigacion y Aplicaciones, CAC, CNEA, (1650) San Martin, Pcia. de Buenos Aires (Argentina); Stoliar, P. [Gerencia de Investigacion y Aplicaciones, CAC, CNEA, (1650) San Martin, Pcia. de Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, Campus Migueletes, UNSAM, Pcia. de Buenos Aires (Argentina); Fuertes, M.C. [Gerencia Quimica, CAC, CNEA, (1650) San Martin, Pcia. de Buenos Aires (Argentina); Marlasca, F.G.; Levy, P. [Gerencia de Investigacion y Aplicaciones, CAC, CNEA, (1650) San Martin, Pcia. de Buenos Aires (Argentina)

    2012-08-15

    We study the electric pulse induced resistance switching of TiO{sub 2}-Ag contacts at room temperature, exploring both unipolar and bipolar switching modes. Initially we observed unipolar response. After hundred pulsing cycles the unipolar switching response vanishes but the device can still be operated in bipolar switching regime. The underlying mechanism for resistance switching is modeled in terms of formation and rupture of filament, and movement of oxygen vacancies.

  11. Bipolar resistive switching in different plant and animal proteins

    KAUST Repository

    Bag, A.

    2014-06-01

    We report bipolar resistive switching phenomena observed in different types of plant and animal proteins. Using protein as the switching medium, resistive switching devices have been fabricated with conducting indium tin oxide (ITO) and Al as bottom and top electrodes, respectively. A clockwise bipolar resistive switching phenomenon is observed in all proteins. It is shown that the resistive switching phenomena originate from the local redox process in the protein and the ion exchange from the top electrode/protein interface.

  12. Analytical Modeling and Simulation of Four-Switch Hybrid Power Filter Working with Sixfold Switching Symmetry

    Czech Academy of Sciences Publication Activity Database

    Tlustý, J.; Škramlík, Jiří; Švec, J.; Valouch, Viktor

    2012-01-01

    Roč. 2012, č. 292178 (2012), s. 1-17 ISSN 1024-123X Institutional support: RVO:61388998 Keywords : analytical modeling * four-switch hybrid power filter * sixfold switching symmetry Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.383, year: 2012 http://www.hindawi.com/journals/mpe/2012/292178/

  13. Optimization of multi-branch switched diversity systems

    KAUST Repository

    Nam, Haewoon

    2009-10-01

    A performance optimization based on the optimal switching threshold(s) for a multi-branch switched diversity system is discussed in this paper. For the conventional multi-branch switched diversity system with a single switching threshold, the optimal switching threshold is a function of both the average channel SNR and the number of diversity branches, where computing the optimal switching threshold is not a simple task when the number of diversity branches is high. The newly proposed multi-branch switched diversity system is based on a sequence of switching thresholds, instead of a single switching threshold, where a different diversity branch uses a different switching threshold for signal comparison. Thanks to the fact that each switching threshold in the sequence can be optimized only based on the number of the remaining diversity branches, the proposed system makes it easy to find these switching thresholds. Furthermore, some selected numerical and simulation results show that the proposed switched diversity system with the sequence of optimal switching thresholds outperforms the conventional system with the single optimal switching threshold. © 2009 IEEE.

  14. Switched capacitor DC-DC converter with switch conductance modulation and Pesudo-fixed frequency control

    DEFF Research Database (Denmark)

    Larsen, Dennis Øland; Vinter, Martin; Jørgensen, Ivan Harald Holger

    A switched capacitor dc-dc converter with frequency-planned control is presented. By splitting the output stage switches in eight segments the output voltage can be regulated with a combination of switching frequency and switch conductance. This allows for switching at predetermined frequencies, 31.......25 kHz, 250 kHz, 500 kHz, and 1 MHz, while maintaining regulation of the output voltage. The controller is implemented in 180 CMOS with a 1/3 series-parallel output stage designed for 3.6–4.2 V input, 1.2 V output, and 1–40 mA load current. The proposed controller is compared with a co-integrated pulse...

  15. Ways to Optimize Analogue Switched Circuits

    Directory of Open Access Journals (Sweden)

    J. Hospodka

    2008-12-01

    Full Text Available This paper describes how analogue switched circuits (switched-capacitor and switched-current circuits can be optimized by means of a personal computer. The optimization of this kind of circuits is not so common and their analysis is more difficult in comparison with continuously working circuits. Firstly, the nonidealities occurring in these circuits whose effect on their characteristics should be optimized are discussed. Then a few ways to analyze analogue switched circuits are shown. From all optimization algorithms applicable for this kind of optimization, two ones that seem to be the most promising are proposed. The differential evolution (one of evolutionary algorithms combined with the simplex method was found to be most appropriate from these two ones. Two types of programs are required for the optimization of these circuits: a program for implementing calculations of the used optimization algorithm and a program for the analysis of the optimized circuit. Several suitable computer programs from both of the groups together with their proper settings according to authors’ experience are proposed. At the end of the paper, an example of a switched-current circuit optimization documenting the previous description is presented.

  16. Arduino Based RFID Line Switching Using SSR

    Directory of Open Access Journals (Sweden)

    Michael E.

    2017-10-01

    Full Text Available The importance of line switching cannot be overemphasized as they are used to connect and disconnect substations to and from a distribution grid. At the cradle of technology line switching was achieved via the use of manual switches or fuses which could endanger life as a result of electrocution when expose during maintenance. This ill prompted the development of automated line switching using relays and contactors. With time this tends to fail as a result of wearing of the contact which is as a result of arcing and low voltage. To avert all these ills this paper presents Arduino based Radio Frequency Identification RFID line switching using Solid State Relay SSR. This is to ensure the safety of operators or technologist and to also avert the problem associated with relays and contactors using SSR. This was achieved using RFID RC-522 reader ardriuno Uno SSR and other discrete components. The system was tested and worked perfectly reducing the risk of electrocution and eliminating damage wearing of the contacts common with contactors and relays.

  17. Commitment and Switching Intentions: Customers and Brands

    Directory of Open Access Journals (Sweden)

    Juliana Werneck Rodrigues

    2012-12-01

    Full Text Available This study aims to evaluate the relationship between a customer’s brand switching intentions and his commitment to a brand. Based on a literature review, constructs related to customer brand commitment were identified (affective and continuance commitment, trust, satisfaction, switching costs and alternative attractiveness and their roles in the formation of brand switching intentions hypothesized. Through a cross-sectional survey, a sample of 201 smartphone users was collected to test the proposed relationships. Data analysis was carried out via structural equations modeling, with direct effects of trust, satisfaction, switching costs and alternative attractiveness upon the different kinds of commitment being verified. Furthermore, both types of brand commitment (affective and continuance were found to negatively impact a customer’s intention to switch brands. Regarding enterprise customer strategies, the research findings suggest that, if firms are able to track customer brand commitment, they could use such knowledge to develop better relationship strategies, minimizing customer defection and further developing customer value to the company.

  18. ABC-model analysis of gain-switched pulse characteristics in low-dimensional semiconductor lasers

    Science.gov (United States)

    Bao, Xumin; Liu, Yuejun; Weng, Guoen; Hu, Xiaobo; Chen, Shaoqiang

    2018-01-01

    The gain-switching dynamics of low-dimensional semiconductor lasers is simulated numerically by using a two-dimensional rate-equation model. Use is also made of the ABC model, where the carrier recombination rate is described by a function of carrier densities including Shockley – Read – Hall (SRH) recombination coefficient A, spontaneous emission coefficient B and Auger recombination coefficient C. Effects of the ABC parameters on the ultrafast gain-switched pulse characteristics with high-density pulse excitation are analysed. It is found that while the parameter A has almost no obvious effects, the parameters B and C have distinctly different effects: B influences significantly the delay time of the gain-switched pulse, while C affects mainly the pulse intensity.

  19. Switching Induced by Poisson Radio-Frequency Pulses in Nonlinear Micromechanical Oscillators

    Science.gov (United States)

    Zou, Jie; Buvaev, Sanal; Chan, H. B.

    2010-03-01

    We study switching induced by Poisson radio-frequency (RF) pulses in nonlinear micromechanical oscillators. Under sufficiently large periodic excitation, nonlinear micromechanical oscillators possess multiple oscillation states with different amplitudes. The presence of noise enables the system to switch between these states. We find that in the vicinity of the bifurcation point the activation barrier, which is given by the logarithm of the switching rate, has a logarithmic dependence on the mean rate of Poisson RF pulses. Moreover, the measured dependence of the activation barrier on the distance to the saddle-node bifurcation η is consistent with predicted universal scaling relationships. While for white Gaussian noise the activation barrier shows a clean 3/2 power-law dependence on η, for modulated Poisson pulses the power-law has a different power of 1/2 with an additional logarithmic factor. Our measured critical exponents are in accordance with theoretical predictions.

  20. Optimized H.264/AVC-Based Bit Stream Switching for Mobile Video Streaming

    Directory of Open Access Journals (Sweden)

    Liebl Günther

    2006-01-01

    Full Text Available We show the suitability of H.264/MPEG-4 AVC extended profile for wireless video streaming applications. In particular, we exploit the advanced bit stream switching capabilities using SP/SI pictures defined in the H.264/MPEG-4 AVC standard. For both types of switching pictures, optimized encoders are developed. We introduce a framework for dynamic switching and frame scheduling. For this purpose we define an appropriate abstract representation for media encoded for video streaming, as well as for the characteristics of wireless variable bit rate channels. The achievable performance gains over H.264/MPEG-4 AVC with constant bit rate (CBR encoding are shown for wireless video streaming over enhanced GPRS (EGPRS.

  1. The arterial switch operation: 25-year experience with 258 patients.

    Science.gov (United States)

    Rudra, Harish S; Mavroudis, Constantine; Backer, Carl L; Kaushal, Sunjay; Russell, Hyde; Stewart, Robert D; Webb, Catherine; Sullivan, Christine

    2011-11-01

    At our institution, the arterial switch operation for transposition of the great arteries has transitioned from the Gore-Tex patch (W.L. Gore & Associates, Flagstaff, AZ) for pulmonary artery reconstruction to redundant pantaloon pericardial patch (RPPP). The (U-shaped) coronary artery button was used for coronary reimplantation. This study investigates overall mortality and factors for neopulmonary artery, neoaortic, and coronary artery surgical reintervention. We performed a retrospective chart review of all patients who underwent arterial switch between 1983 and 2007. Our surgical database, operative reports, and cardiology clinic charts were reviewed. Time to event was plotted as Kaplan-Meier curves. Predictors of time-to-event were examined using Cox proportional hazard modeling. A total of 258 patients underwent arterial switch during the study. Mortality declined from 15% (era I: 1983 to 1990) to 11% (era II: 1991 to 1998) to 7% (era III: 1999 to 2007). Era III had a significantly later time to death compared with era I (hazard ratio [HR] 0.62, p = 0.04). The RPPP had a lower neopulmonary artery reintervention rate compared with Gore-Tex; 9 of 225 (4%) versus 3 of 21 (14%), p = 0.008. Complex anatomy increased risk for neopulmonary reintervention (HR 3.3, p = 0.03). Surgical reintervention rate for coronary arteries was 2%. Complex coronary anatomy (HR 17.9, p = 0.01) predicted coronary reintervention. Predictors of neoaortic reintervention were prior pulmonary artery band (HR 4.3, p = 0.03), complex anatomy (HR 3.5, p = 0.01), and coronary artery anatomy (HR 3.5, p = 0.04). Arterial switch operation mortality has decreased. Conversion to RPPP reduced neopulmonary artery reintervention. The (U-shaped) coronary artery button technique is associated with low coronary reintervention rates. Complex coronary anatomy increases coronary and aortic reintervention. Prior pulmonary artery banding and complex anatomy increase aortic reintervention. Copyright © 2011

  2. Magnetic switch for reactor control rod. [LMFBR

    Science.gov (United States)

    Germer, J.H.

    1982-09-30

    A magnetic reed switch assembly is described for activating an electromagnetic grapple utilized to hold a control rod in position above a reactor core. In normal operation the magnetic field of a permanent magnet is short-circuited by a magnetic shunt, diverting the magnetic field away from the reed switch. The magnetic shunt is made of a material having a Curie-point at the desired release temperature. Above that temperature the material loses its ferromagnetic properties, and the magnetic path is diverted to the reed switch which closes and short-circuits the control circuit for the control rod electro-magnetic grapple which allows the control rod to drop into the reactor core for controlling the reactivity of the core.

  3. New Photonic System for Optical Packet Switching

    Directory of Open Access Journals (Sweden)

    F. Rudge Barbosa

    2003-08-01

    Full Text Available Fast optical switching (ms timebase is realized by using a RF frequency tone inserted in the optical packet that carries a digital payload. By using a highly selective RF filtering for optical packet header frequency recognition, we have obtained excellent performance in optical switching function.. The RF header is detected at optical node input, and signals the node switching control, which instantly directs the packet to a prescribed output. No electronic processing of the digital payload is performed. The optical circuit is noise-free, has very low crosstalk, and is extremely selective in header frequency detection. BER measurements for payload consistently yield figures as low as 10-12 . This system is applicable to optical metropolitan and access networks, and is fully compatible with DWDM systems.

  4. A nanoplasmonic switch based on molecular machines

    KAUST Repository

    Zheng, Yue Bing

    2009-06-01

    We aim to develop a molecular-machine-driven nanoplasmonic switch for its use in future nanophotonic integrated circuits (ICs) that have applications in optical communication, information processing, biological and chemical sensing. Experimental data show that an Au nanodisk array, coated with rotaxane molecular machines, switches its localized surface plasmon resonances (LSPR) reversibly when it is exposed to chemical oxidants and reductants. Conversely, bare Au nanodisks and disks coated with mechanically inert control compounds, do not display the same switching behavior. Along with calculations based on time-dependent density functional theory (TDDFT), these observations suggest that the nanoscale movements within surface-bound "molecular machines" can be used as the active components in plasmonic devices. ©2009 IEEE.

  5. Huge capacity optical packet switching and buffering.

    Science.gov (United States)

    Shinada, Satoshi; Furukawa, Hideaki; Wada, Naoya

    2011-12-12

    We demonstrate 2.56 Tbit/s/port dual-polarization DWDM/DQPSK variable-length optical packet (20 Gbit/s × 64 wavelengths × 2 polarizations) switching and buffering by using a 2×2 optical packet switch (OPS) system. The optical data plane of the OPS system was constructed of multi-connected electro-optical switches and fiber delay lines. The accumulated polarization dependent loss of each optical path in the data plane was less than 5 dB. This low-polarization-dependence OPS system enabled us to handle DWDM/DQPSK optical packets (1.28 Tbit/s/port) with time-varying polarization after transmission through 100 km fiber in the field. © 2011 Optical Society of America

  6. Metallic oxide switches using thick film technology

    Science.gov (United States)

    Patel, D. N.; Williams, L., Jr.

    1974-01-01

    Metallic oxide thick film switches were processed on alumina substrates using thick film technology. Vanadium pentoxide in powder form was mixed with other oxides e.g., barium, strontium copper and glass frit, ground to a fine powder. Pastes and screen printable inks were made using commercial conductive vehicles and appropriate thinners. Some switching devices were processed by conventional screen printing and firing of the inks and commercial cermet conductor terminals on 96% alumina substrates while others were made by applying small beads or dots of the pastes between platinum wires. Static, and dynamic volt-ampere, and pulse tests indicate that the switching and self-oscillatory characteristics of these devices could make them useful in memory element, oscillator, and automatic control applications.

  7. Switching overvoltages in offshore wind power grids

    DEFF Research Database (Denmark)

    Arana Aristi, Ivan

    Switching transients in wind turbines, the collection grid, the export system and the external grid in offshore wind farms, during normal or abnormal operation, are the most important phenomena when conducting insulation coordination studies. However, the recommended models and methods from...... electrical systems and the topic of transients is given in Chapter 1. In Chapter 2 it is described how the component and sub-system models are developed and used from an applied point of view, where common and detail models are mentioned. In Chapter 3 results from frequency domain measurement on transformers...... and cables are presented. In Chapter 4 results from time domain measurements and simulations of switching operations in offshore wind power grids are described. Specifically, switching operations on a single wind turbine, the collection grid, the export system and the external grid measured in several real...

  8. Radio frequency-assisted fast superconducting switch

    Science.gov (United States)

    Solovyov, Vyacheslav; Li, Qiang

    2017-12-05

    A radio frequency-assisted fast superconducting switch is described. A superconductor is closely coupled to a radio frequency (RF) coil. To turn the switch "off," i.e., to induce a transition to the normal, resistive state in the superconductor, a voltage burst is applied to the RF coil. This voltage burst is sufficient to induce a current in the coupled superconductor. The combination of the induced current with any other direct current flowing through the superconductor is sufficient to exceed the critical current of the superconductor at the operating temperature, inducing a transition to the normal, resistive state. A by-pass MOSFET may be configured in parallel with the superconductor to act as a current shunt, allowing the voltage across the superconductor to drop below a certain value, at which time the superconductor undergoes a transition to the superconducting state and the switch is reset.

  9. The preparation effect in task switching: carryover of SOA.

    Science.gov (United States)

    Altmann, Erik M

    2004-01-01

    A common finding in task-switching studies is switch preparation (commonly known as the preparation effect), in which a longer interval between task cue and trial stimulus (i.e., a longer stimulus onset asynchrony, or SOA) reduces the cost of switching to a different task. Three experiments link switch preparation to within-subjects manipulations of SOA. In Experiment 1, SOA was randomized within subjects, producing switch preparation that was more pronounced when the SOA switched from the previous trial than when the SOA repeated. In Experiment 2, SOA was blocked within subjects, producing switch preparation but not on the first block of trials. In Experiment 3, SOA was manipulated between subjects with sufficient statistical power to detect switch preparation, but the effect was absent. The results favor an encoding view of cognitive control, but show that any putative switching mechanism reacts lazily when exposed to only one SOA.

  10. Ultra High-Speed Radio Frequency Switch Based on Photonics.

    Science.gov (United States)

    Ge, Jia; Fok, Mable P

    2015-11-26

    Microwave switches, or Radio Frequency (RF) switches have been intensively used in microwave systems for signal routing. Compared with the fast development of microwave and wireless systems, RF switches have been underdeveloped particularly in terms of switching speed and operating bandwidth. In this paper, we propose a photonics based RF switch that is capable of switching at tens of picoseconds speed, which is hundreds of times faster than any existing RF switch technologies. The high-speed switching property is achieved with the use of a rapidly tunable microwave photonic filter with tens of gigahertz frequency tuning speed, where the tuning mechanism is based on the ultra-fast electro-optics Pockels effect. The RF switch has a wide operation bandwidth of 12 GHz and can go up to 40 GHz, depending on the bandwidth of the modulator used in the scheme. The proposed RF switch can either work as an ON/OFF switch or a two-channel switch, tens of picoseconds switching speed is experimentally observed for both type of switches.

  11. Weight change after an atypical antipsychotic switch.

    Science.gov (United States)

    Ried, L Douglas; Renner, Bernard T; Bengtson, Michael A; Wilcox, Brian M; Acholonu, Wilfred W

    2003-10-01

    Atypical antipsychotics successfully treat schizophrenia and other conditions, with a lower incidence of extrapyramidal side effects than other agents used in treatment of these disorders. However, some atypical antipsychotics are associated with weight gain. To quantify the impact on weight and identify atypical antipsychotics causing the least amount of weight gain among patients switched from risperidone to olanzapine and olanzapine to risperidone. Patients included in the study (n = 86) were > or =18 years and had received > or =2 prescriptions for risperidone or olanzapine for > or =60 days, switched to the other atypical antipsychotic, and were dispensed > or =2 prescriptions for at least 60 days after the index date. Age, weight, and body mass index (BMI) were retrospectively abstracted from automated databases containing patient-specific prescription and vital sign information. At the time of their switch, the average patient age was 53.2 years (range 25-83). The average weight change in patients switched to olanzapine (n = 47) was +2.3 kg (p = 0.01) and the BMI change was +0.8 kg/m(2) (p = 0.02). The average percent body weight change was +2.8% and the BMI change was +3.0%. The average weight change after patients switched to risperidone (n = 39) was -0.45 kg (p = 0.69) and BMI change was -0.2 kg/m2 (p = 0.64). The average percentage weight change was -0.4% and BMI change was -0.5%. Practitioners' concern regarding weight changes after switching atypical antipsychotics seems warranted and patients should be provided consistent, ongoing weight monitoring. Further investigations should examine whether weight changes associated with atypical antipsychotic treatment further jeopardize this already at-risk population for severe comorbid conditions such as hypertension, coronary artery disease, and type 2 diabetes.

  12. Photonic Switching Devices Using Light Bullets

    Science.gov (United States)

    Goorjian, Peter M. (Inventor)

    1999-01-01

    A unique ultra-fast, all-optical switching device or switch is made with readily available, relatively inexpensive, highly nonlinear optical materials. which includes highly nonlinear optical glasses, semiconductor crystals and/or multiple quantum well semiconductor materials. At the specified wavelengths. these optical materials have a sufficiently negative group velocity dispersion and high nonlinear index of refraction to support stable light bullets. The light bullets counter-propagate through, and interact within the waveguide to selectively change each others' directions of propagation into predetermined channels. In one embodiment, the switch utilizes a rectangularly planar slab waveguide. and further includes two central channels and a plurality of lateral channels for guiding the light bullets into and out of the waveguide. An advantage of the present all-optical switching device lies in its practical use of light bullets, thus preventing the degeneration of the pulses due to dispersion and diffraction at the front and back of the pulses. Another advantage of the switching device is the relative insensitivity of the collision process to the time difference in which the counter-propagating pulses enter the waveguide. since. contrary to conventional co-propagating spatial solitons, the relative phase of the colliding pulses does not affect the interaction of these pulses. Yet another feature of the present all-optical switching device is the selection of the light pulse parameters which enables the generation of light bullets in nonlinear optical materials. including highly nonlinear optical glasses and semiconductor materials such as semiconductor crystals and/or multiple quantum well semiconductor materials.

  13. Two Bistable Switches Govern M Phase Entry.

    Science.gov (United States)

    Mochida, Satoru; Rata, Scott; Hino, Hirotsugu; Nagai, Takeharu; Novák, Béla

    2016-12-19

    The abrupt and irreversible transition from interphase to M phase is essential to separate DNA replication from chromosome segregation. This transition requires the switch-like phosphorylation of hundreds of proteins by the cyclin-dependent kinase 1 (Cdk1):cyclin B (CycB) complex. Previous studies have ascribed these switch-like phosphorylations to the auto-activation of Cdk1:CycB through the removal of inhibitory phosphorylations on Cdk1-Tyr15 [1, 2]. The positive feedback in Cdk1 activation creates a bistable switch that makes mitotic commitment irreversible [2-4]. Here, we surprisingly find that Cdk1 auto-activation is dispensable for irreversible, switch-like mitotic entry due to a second mechanism, whereby Cdk1:CycB inhibits its counteracting phosphatase (PP2A:B55). We show that the PP2A:B55-inhibiting Greatwall (Gwl)-endosulfine (ENSA) pathway is both necessary and sufficient for switch-like phosphorylations of mitotic substrates. Using purified components of the Gwl-ENSA pathway in a reconstituted system, we found a sharp Cdk1 threshold for phosphorylation of a luminescent mitotic substrate. The Cdk1 threshold to induce mitotic phosphorylation is distinctly higher than the Cdk1 threshold required to maintain these phosphorylations-evidence for bistability. A combination of mathematical modeling and biochemical reconstitution show that the bistable behavior of the Gwl-ENSA pathway emerges from its mutual antagonism with PP2A:B55. Our results demonstrate that two interlinked bistable mechanisms provide a robust solution for irreversible and switch-like mitotic entry. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Manufacturing fuel-switching capability, 1988

    Energy Technology Data Exchange (ETDEWEB)

    1991-09-01

    Historically, about one-third of all energy consumed in the United States has been used by manufacturers. About one-quarter of manufacturing energy is used as feedstocks and raw material inputs that are converted into nonenergy products; the remainder is used for its energy content. During 1988, the most recent year for which data are available, manufacturers consumed 15.5 quadrillion British thermal units (Btu) of energy to produce heat and power and to generate electricity. The manufacturing sector also has widespread capabilities to switch from one fuel to another for either economic or emergency reasons. There are numerous ways to define fuel switching. For the purposes of the Manufacturing Energy Consumption Survey (MECS), fuel switching is defined as the capability to substitute one energy source for another within 30 days with no significant modifications to the fuel-consuming equipment, while keeping production constant. Fuel-switching capability allows manufacturers substantial flexibility in choosing their mix of energy sources. The consumption of a given energy source can be maximized if all possible switching into that energy source takes place. The estimates in this report are based on data collected on the 1988 Manufacturing Energy Consumption Survey (MECS), Forms 846 (A through C). The EIA conducts this national sample survey of manufacturing energy consumption on a triennial basis. The MECS is the only comprehensive source of national-level data on energy-related information for the manufacturing industries. The MECS was first conducted in 1986 to collect data for 1985. This report presents information on the fuel-switching capabilities of manufacturers in 1988. This report is the second of a series based on the 1988 MECS. 8 figs., 31 tabs.

  15. Manufacturing fuel-switching capability, 1988

    International Nuclear Information System (INIS)

    1991-09-01

    Historically, about one-third of all energy consumed in the United States has been used by manufacturers. About one-quarter of manufacturing energy is used as feedstocks and raw material inputs that are converted into nonenergy products; the remainder is used for its energy content. During 1988, the most recent year for which data are available, manufacturers consumed 15.5 quadrillion British thermal units (Btu) of energy to produce heat and power and to generate electricity. The manufacturing sector also has widespread capabilities to switch from one fuel to another for either economic or emergency reasons. There are numerous ways to define fuel switching. For the purposes of the Manufacturing Energy Consumption Survey (MECS), fuel switching is defined as the capability to substitute one energy source for another within 30 days with no significant modifications to the fuel-consuming equipment, while keeping production constant. Fuel-switching capability allows manufacturers substantial flexibility in choosing their mix of energy sources. The consumption of a given energy source can be maximized if all possible switching into that energy source takes place. The estimates in this report are based on data collected on the 1988 Manufacturing Energy Consumption Survey (MECS), Forms 846 (A through C). The EIA conducts this national sample survey of manufacturing energy consumption on a triennial basis. The MECS is the only comprehensive source of national-level data on energy-related information for the manufacturing industries. The MECS was first conducted in 1986 to collect data for 1985. This report presents information on the fuel-switching capabilities of manufacturers in 1988. This report is the second of a series based on the 1988 MECS. 8 figs., 31 tabs

  16. Stability of Randomly Switched Diffusions

    DEFF Research Database (Denmark)

    Schiøler, Henrik; Leth, John-Josef; Gholami, Mehdi

    2012-01-01

    to be quantified by a Lyapunov function candidate and an associated growth rate equation. For the set of Lyapunov functions a compatibility criterion is assumed to be fulfilled bounding the ratio between pairs of Lyapunov functions. The established criterion is shown to be equivalent to an exact criterion...... for the almost sure convergence of an associated process bounding moments of the process under study. Examples are provided to illustrate the use of the established criterion....

  17. Switching to a Mac For Dummies

    CERN Document Server

    Reinhold, Arnold

    2007-01-01

    Thinking of making the switch from your PC to a Mac? Congratulations! You're in for a great, virus-free ride. And Switching to Mac For Dummies makes it smoother than you ever imagined. From buying the Mac that's right for you to transferring your files to breaking your old Windows habits and learning to do things the (much easier) Mac way, it makes the whole process practically effortless. Whether you've been using Windows XP, Vista, or even Linux, you'll find simple, straightforward ways to make your transition go smoothly. That will leave you plenty of time to get familiar with Mac'

  18. The Morrison Bearingless Switched Reluctance Motor

    Science.gov (United States)

    Wong, David S.

    2004-01-01

    Switched reluctance motors typically consist of pairs of poles protruding outward from a central rotor, surrounded by pairs of coils protruding inward from a stator. The pairs of coils, positioned a short distance from opposing sides of the rotor, are connected in series. A current runs through the coils, generating a magnetic flux between the coils. This attracts the protruding poles on the rotor, and just as the poles on the rotor approach the coils, the current to the coils is inverted, repelling the rotor s poles as they pass the coils. This current switching, back and forth, provides a continuous rotational torque to the rotor. reliability, durability, low cost, and operation in adverse environments such as high temperatures, extreme temperature variations, and high rotational speeds. However, because rotors are often manufactured with minute flaws due to imperfections in the machining process, traditional switched reluctance motors often suffer from substantial amounts of vibration. In addition, the current in the coils imparts a strong radial magnetic force on the rotor; the continuous alternating of the direction of this force also causes vibration. As a result, switched reluctance motors require bearings that, run at high speeds, can require lubrication apparatus and are subject to problems with heat and wear. My mentor s recent invention, the "Bearingless" Switched Reluctance Motor, actually uses magnetic bearings instead of traditional physical bearings. Sensors are used to continuously determine the position of the rotor. A computer reads the position sensor input, performs calculations, and outputs a current to a set of extra coils (in addition to the coils rotating the rotor). This current provides a magnetic force that counters and damps the vibration. The sense-calculate-update loop iterates more than thirty thousand times per second. For now, our goal is to have the rotor rotate at about 6000 rprn, and at that speed, the magnetic bearing is

  19. Simulation of plasma erosion opening switches

    International Nuclear Information System (INIS)

    Mason, R.J.; Jones, M.E.

    1988-01-01

    Recent progress in the modeling of Plasma Erosion Opening Switches is reviewed, and new results from both fluid and particle simulation compared. Three-fluid simulations with the ANTHEM code for switches on the NRL GAMBLE I machine and SNL PBFA II machine have shown strong dependence of the opening dynamics on the anode structure, the threshold for electron emission, on the possible presence of anomalous resistivity, and on advection of the magnetic field with cathode emitted electrons. Simulations with the implicit particle-in-cell code ISIS confirm these observations, but manifest broader current channels---in better agreement with GAMBLE I experimental results. 7 refs., 3 figs

  20. Design of a Clap Activated Switch

    Directory of Open Access Journals (Sweden)

    Seyi Stephen OLOKEDE

    2008-12-01

    Full Text Available This paper presents the design of a clap activated switch device that will serve well in different phono-controlled applications, providing inexpensive key and at the same time flee from false triggering.This involves the design of various sages consisting of the pickup transducer, low frequency, audio low power and low noise amplifier, timer, bistable and switches. It also consists of special network components to prevent false triggering and ensure desired performance objectives. A decade counter IC serves the bistable function instead of flip-flop, special transistor and edge triggering network for low audio frequency.

  1. Open switching of current varying inductance

    International Nuclear Information System (INIS)

    Zubkov, P.I.; Lukyanchikov, L.A.; Ten, K.A.

    1990-01-01

    The electromotive force of induction occurs in a varying inductance of a current circuit part. It can be used to control and switch the current. The effect, occurring under the forced inductance decrease, is used widely for explosive magnetic generators to produce high currents, to store high-density energy and to generate superhigh magnetic fields. This paper gives an analysis of open switching of the currents by varying inductance in some simple electrotechnical models of circuits used in pulse power engineering to obtain high energies

  2. A novel photonic crystal fibre switch

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Hermann, D.S.; Broeng, Jes

    2003-01-01

    A new thermo-optic fibre switch is demonstrated, which utilizes the phase transitions of a thermochromic liquid crystal inside a photonic crystal fibre. We report an extinction ratio of 60 dB and an insertion loss of 1 dB.......A new thermo-optic fibre switch is demonstrated, which utilizes the phase transitions of a thermochromic liquid crystal inside a photonic crystal fibre. We report an extinction ratio of 60 dB and an insertion loss of 1 dB....

  3. Resistance switching in silver - manganite contacts

    International Nuclear Information System (INIS)

    Gomez-Marlasca, F; Levy, P

    2009-01-01

    We investigate the electric pulse induced resistance switching in a transition metal oxide-metal contact at room temperature - a non volatile, reversible and multilevel memory device. Using a simple multiterminal configuration, we find that the complementary effect -in which the contact resistance of each pulsed electrode displays variations of opposite sign- is strongly influenced by the history of the pulsing procedure. Loops performed by varying the magnitude and sign of the stimulus at each pulsed electrode allow to disentangle their sole contribution at different stages of the process. Electromigration of oxygen ions and vacancies is discussed as participating at the core of the underlying mechanisms for resistance switching.

  4. Theory of circuit block switch-off

    Directory of Open Access Journals (Sweden)

    S. Henzler

    2004-01-01

    Full Text Available Switching-off unused circuit blocks is a promising approach to supress static leakage currents in ultra deep sub-micron CMOS digital systems. Basic performance parameters of Circuit Block Switch-Off (CBSO schemes are defined and their dependence on basic circuit parameters is estimated. Therefore the design trade-off between strong leakage suppression in idle mode and adequate dynamic performance in active mode can be supported by simple analytic investigations. Additionally, a guideline for the estimation of the minimum time for which a block deactivation is useful is derived.

  5. Voltage reapplication rate control for commutation of thyristors

    Science.gov (United States)

    Rippel, Wally E. (Inventor); Edwards, Dean B. (Inventor)

    1982-01-01

    A circuit for commutating a thyristor (21) by shunting its current for a minimum interval, thereby removing sustaining voltage to said thyristor, then subsequently restoring voltage to said thyristor at a predetermined rate, utilizes a series combination of a commutation electronic switch (22) and an isolated dc voltage supply (23) connected in parallel with the thyristor. The voltage supply is arranged with a polarity that permits the current flowing through the thyristor in one direction to be bypassed through the series combination while the commutation switch is turned on and to reverse bias the thyristor when the commutation switch is fully on. A dv/dt control circuit (24) limits the rate of rise of voltage across the commutation switch (22) as it is turned off in response to a command input signal. The dv/dt control circuit is comprised of a constant current drive (31) and a capacitor (32) connected between the output terminal of the commutation switch and the control input terminal of the commutation switch. The thyristor may be a triac (40) with two commutation switches (42, 43), one for current of each polarity, or with a single commutation switch (55) and a bridge circuit (52-55) for selecting the polarity of the switch (56).

  6. Adaptive synchronized switch damping on an inductor: a self-tuning switching law

    Science.gov (United States)

    Kelley, Christopher R.; Kauffman, Jeffrey L.

    2017-03-01

    Synchronized switch damping (SSD) techniques exploit low-power switching between passive circuits connected to piezoelectric material to reduce structural vibration. In the classical implementation of SSD, the piezoelectric material remains in an open circuit for the majority of the vibration cycle and switches briefly to a shunt circuit at every displacement extremum. Recent research indicates that this switch timing is only optimal for excitation exactly at resonance and points to more general optimal switch criteria based on the phase of the displacement and the system parameters. This work proposes a self-tuning approach that implements the more general optimal switch timing for synchronized switch damping on an inductor (SSDI) without needing any knowledge of the system parameters. The law involves a gradient-based search optimization that is robust to noise and uncertainties in the system. Testing of a physical implementation confirms this law successfully adapts to the frequency and parameters of the system. Overall, the adaptive SSDI controller provides better off-resonance steady-state vibration reduction than classical SSDI while matching performance at resonance.

  7. Optically triggered high voltage switch network and method for switching a high voltage

    Energy Technology Data Exchange (ETDEWEB)

    El-Sharkawi, Mohamed A. (Renton, WA); Andexler, George (Everett, WA); Silberkleit, Lee I. (Mountlake Terrace, WA)

    1993-01-19

    An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

  8. Optically triggered high voltage switch network and method for switching a high voltage

    Science.gov (United States)

    El-Sharkawi, Mohamed A.; Andexler, George; Silberkleit, Lee I.

    1993-01-19

    An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

  9. Comparison of MEMS switches and PIN diodes for switched dual tuned RF coils.

    Science.gov (United States)

    Maunder, Adam; Rao, Madhwesha; Robb, Fraser; Wild, Jim M

    2018-03-09

    To evaluate the performance of micro-electromechanical systems (MEMS) switches against PIN diodes for switching a dual-tuned RF coil between 19 F and 1 H resonant frequencies for multi-nuclear lung imaging. A four-element fixed-phase and amplitude transmit-receive RF coil was constructed to provide homogeneous excitation across the lungs, and to serve as a test system for various switching methods. The MR imaging and RF performance of the coil when switched between the 19 F and 1 H frequencies using MEMS switches, PIN diodes and hardwired configurations were compared. The performance of the coil with MEMS or PIN diode switching was comparable in terms of RF measurements, transmit efficiency and image SNR on both 19 F and 1 H nuclei. When the coil was not switched to the resonance frequency of the respective nucleus being imaged, reductions in the transmit efficiency were observed of 32% at the 19 F frequency and 12% at the 1 H frequency. The coil provides transmit field homogeneity of ±12.9% at the 1 H frequency and ±14.4% at the 19 F frequency in phantoms representing the thorax with the air space of the lungs filled with perfluoropropane gas. MEMS and PIN diodes were found to provide comparable performance in on-state configuration, while MEMS were more robust in off-state high-powered operation (>1 kW), providing higher isolation and requiring a lower DC switching voltage than is needed for reverse biasing of PIN diodes. In addition, clear benefits of switching between the 19 F and 1 H resonances were demonstrated, despite the proximity of their Larmor frequencies. © 2018 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

  10. A 3rd Order Low Power Switched Current Sigma-Delta Modulator

    DEFF Research Database (Denmark)

    Jørgensen, Ivan Herald Holger; Bogason, Gudmundur

    1996-01-01

    This paper presents a 3rd order switched current Sigma-Delta modulator. The Sigma-Delta modulator operates at a sampling rate of 600kHz and the signal band is 5.5kHz, i.e. an oversampling factor of 54.5 is used. Multiple input signals are used to reduce the internal signal swings which results...

  11. Generation of dark and bright pulses in an SOA-based Q-switched fiber laser

    Science.gov (United States)

    Pan, Honggang; Zhang, Ailing; Tong, Zhengrong

    2017-08-01

    Bright and dark pulses in a Q-switched optical fiber laser based on a semiconductor optical amplifier were demonstrated. By changing the setting of the polarization controllers, bright or dark pulses with differing pulse widths and frequency repetition rates can be obtained. The bright pulse and dark pulse are formed mainly by the effect of gain dispersion of the semiconductor optical amplifier.

  12. Switching antidepressants after a first selective serotonin reuptake inhibitor in major depressive disorder: a systematic review

    NARCIS (Netherlands)

    Ruhé, Henricus G.; Huyser, Jochanan; Swinkels, Jan A.; Schene, Aart H.

    2006-01-01

    OBJECTIVE: Selective serotonin reuptake inhibitors (SSRIs) are frequently used as a first antidepressant for major depressive disorder but have response rates of 50% to 60% in daily practice. For patients with insufficient response to SSRIs, switching is often applied. This article aims to

  13. The all-fiber cladding-pumped Yb-doped gain-switched laser

    DEFF Research Database (Denmark)

    Larsen, Casper; Hansen, K. P.; Mattsson, Kent Erik

    2014-01-01

    Gain-switching is an alternative pulsing technique of fiber lasers, which is power scalable and has a low complexity. From a linear stability analysis of rate equations the relaxation oscillation period is derived and from it, the pulse duration is defined. Good agreement between the measured pul...

  14. Npvf: Hypothalamic Biomarker of Ambient Temperature Independent of Nutritional Status.

    Directory of Open Access Journals (Sweden)

    Julia Jaroslawska

    2015-06-01

    Full Text Available The mechanism by which mice, exposed to the cold, mobilize endogenous or exogenous fuel sources for heat production is unknown. To address this issue we carried out experiments using 3 models of obesity in mice: C57BL/6J+/+ (wild-type B6 mice with variable susceptibility to obesity in response to being fed a high-fat diet (HFD, B6. Ucp1-/- mice with variable diet-induced obesity (DIO and a deficiency in brown fat thermogenesis and B6. Lep-/- with defects in thermogenesis, fat mobilization and hyperphagia. Mice were exposed to the cold and monitored for changes in food intake and body composition to determine their energy balance phenotype. Upon cold exposure wild-type B6 and Ucp1-/- mice with diet-induced obesity burned endogenous fat in direct proportion to their fat reserves and changes in food intake were inversely related to fat mass, whereas leptin-deficient and lean wild-type B6 mice fed a chow diet depended on increased food intake to fuel thermogenesis. Analysis of gene expression in the hypothalamus to uncover a central regulatory mechanism revealed suppression of the Npvf gene in a manner that depends on the reduced ambient temperature and degree of exposure to the cold, but not on adiposity, leptin levels, food intake or functional brown fat.

  15. Small angle neutron scattering study of temperature-independent ...

    Indian Academy of Sciences (India)

    headgroup due to an increase in counterion dissociation decreases the size of ionic micelles, it is the decreased hydration of the headgroup that increases the size of nonionic micelles with an increase in temperature. Herein, we report SANS studies on a formulation of mixed micelles of ionic and nonionic surfactants that.

  16. Temperature-independent photoluminescence response in ZnO:Ce ...

    Indian Academy of Sciences (India)

    2017-12-06

    Dec 6, 2017 ... tion of rare-earth ions. Nowadays, rare-earth-doped ZnO semiconductor is an interesting field of study because of its unique optical properties and promising applications in optoelectronic devices [13–19]. Since cerium oxide (CeO2) has a band gap of ∼3 eV and shows interesting prop- erties similar to that ...

  17. Temperature-independent photoluminescence response in ZnO:Ce ...

    Indian Academy of Sciences (India)

    2017-12-06

    Ce3+ nanophosphors prepared by combustion method and solid-state reaction method is presented in this study. The powder XRD exhibits hexagonal wurtzite phase and crystallite size falls in the nanometre range. The optical ...

  18. Small angle neutron scattering study of temperature-independent ...

    Indian Academy of Sciences (India)

    independent and consists of about 25% of ionic surfactants in the mixed system. Contrast variation SANS measurements by contrast matching one of the surfactant components to the solvent suggest homogeneous single mixed micelles of the two ...

  19. Small angle neutron scattering study of temperature-independent ...

    Indian Academy of Sciences (India)

    independent and consists of about 25% of ionic surfactants in the mixed system. Contrast variation SANS measurements by contrast matching one of the surfactant components to the solvent suggest homogeneous single mixed micelles of.

  20. 6.1-MV, 0.79-MA laser-triggered gas switch for multimodule, multiterawatt pulsed-power accelerators

    Directory of Open Access Journals (Sweden)

    K. R. LeChien

    2010-03-01

    Full Text Available A 6.1-MV, 0.79-MA laser-triggered gas switch (LTGS is used to synchronize the 36 modules of the Z machine at Sandia National Laboratories. Each module includes one switch, which serves as the last command-fired switch of the module, and hence is used to determine the time at which each module electrically closes relative to the other modules. The switch is ∼81-cm in length, ∼45-cm in diameter, and is immersed in mineral oil. The outer switch envelope consists of six corrugated monomer-cast acrylic insulators and five contoured stainless-steel rings. The trigger electrodes are fabricated from copper-infused tungsten. The switch is pressurized with several atmospheres of sulfur hexafluoride (SF_{6}, which is turbulently purged within 2 seconds after every shot. Each switch is powered from a 6-MV, 0.78-MJ Marx generator which pulse charges a 24-nF intermediate-store water capacitor in 1.4-μs. Closure of the switch allows power to flow into pulse-forming transmission lines. The power pulse is subsequently compressed by water switches, which results in a total accelerator output power in excess of 70-TW. A previous version of the LTGS performed exceptionally at a 5.4-MV, 0.7-MA level on an engineering test module used for switch development. It exhibited a 1-σ jitter of ∼5  ns, a prefire and flashover rate less than 0.1%, and a lifetime in excess of 150 shots. When installed on the Z accelerator, however, the switch exhibited a prefire probability of ∼3%, a flashover probability of ∼7%, and a 15-ns jitter. The difference in performance is attributed to several factors such as higher total charge transfer, exposure to more debris, and more stressful dynamic mechanical loading upon machine discharge. Under these conditions, the replacement lifetime was less than ten shots. Since refurbishment of Z in October 2007, there have been three LTGS design iterations to improve the performance at 6.1-MV. The most recent design exhibits a

  1. An Electron-Beam Controlled Semiconductor Switch

    Science.gov (United States)

    1989-11-01

    transport processes are linear, i.e the drift velocity is v = pE and the diffusion coeffient follows the Einstein relation D = ikBT/e where k9 denotes...357/19 SEMICONDUC OR SWITCH WIrH 3,917,943 11/1975 Auston............................. 250/211 J CATHODOLLJNE SCENT ELECTRON

  2. Microprocessor Controlled Capacitor Bank Switching System for ...

    African Journals Online (AJOL)

    In this work, analysis and development of a microprocessor controlled capacitor bank switching system for deployment in a smart distribution network was carried out. This system was implemented by the use of discreet components such as resistors, capacitors, transistor, diode, automatic voltage regulator, with the ...

  3. Isolated and soft-switched power converter

    Science.gov (United States)

    Peng, Fang Zheng; Adams, Donald Joe

    2002-01-01

    An isolated and soft-switched power converter is used for DC/DC and DC/DC/AC power conversion. The power converter includes two resonant tank circuits coupled back-to-back through an isolation transformer. Each resonant tank circuit includes a pair of resonant capacitors connected in series as a resonant leg, a pair of tank capacitors connected in series as a tank leg, and a pair of switching devices with anti-parallel clamping diodes coupled in series as resonant switches and clamping devices for the resonant leg. The power converter is well suited for DC/DC and DC/DC/AC power conversion applications in which high-voltage isolation, DC to DC voltage boost, bidirectional power flow, and a minimal number of conventional switching components are important design objectives. For example, the power converter is especially well suited to electric vehicle applications and load-side electric generation and storage systems, and other applications in which these objectives are important. The power converter may be used for many different applications, including electric vehicles, hybrid combustion/electric vehicles, fuel-cell powered vehicles with low-voltage starting, remote power sources utilizing low-voltage DC power sources, such as photovoltaics and others, electric power backup systems, and load-side electric storage and generation systems.

  4. Acceptable Channel Switching Delays for Mobile TV

    DEFF Research Database (Denmark)

    Fleury, Alexandre; Pedersen, Jakob Schou; Larsen, Lars Bo

    2011-01-01

    This paper presents a user study investigating the acceptability of channel switching delays on mobile television systems. The authors first review the previous work in the area, then propose a study design and present results from its implementation, focusing on the overall acceptability threshold...

  5. Effect of supercoiling on the λ switch

    DEFF Research Database (Denmark)

    Norregaard, Kamilla; Andersson, Magnus; Sneppen, Kim

    2014-01-01

    The lysogenic state of the λ switch is exceptionally stable, still, it is capable of responding to DNA-damage and rapidly enter the lytic state. We invented an assay where PNA mediated tethering of a plasmid allowed for single molecule investigations of the effect of supercoiling on the efficiency...

  6. Analysis of aceismatic properties of switch boards

    International Nuclear Information System (INIS)

    Tabuchi, Yoji; Nishikawa, Atsushi

    1986-01-01

    Recently, in order to limit the disaster at the time of earthquakes to the minimum, the aseismatic properties of electric facilities have been regarded as important. By the development and spread of CAE simulation and experimental modal analysis, aseismatic analysis has become feasible also in design section. Taking an example of the switch boards of rigid construction, which have been used mainly for nuclear power plants, the analysis of the aseismatic properties is explained. In the switch boards of rigid construction, the probability of causing resonance behavior due to earthquakes is decreased by making the structure rigid, thus the aseismatic properties are heightened. In the switch boards of rigid construction, the primary natural frequency is heightened usually to above 20 Hz considering earthquake movement and the response of buildings (in the range from 0.5 to 10 Hz). Since the switch boards of rigid construction can be treated as a rigid body in the examination of structural strength, generally static analysis is carried out. The dimensions and weight tend to be large for increasing the rigidity. In most cases, standard equipment can be adopted if the fixing is made strong. The modal analysis of the natural vibration, static stress analysis and time history response analysis were carried out by finite element method. Also the vibration test on a large vibration table was made. The results are reported. (Kako, I.)

  7. Bisimulation theory for switching linear systems

    NARCIS (Netherlands)

    Pola, G.; van der Schaft, Arjan; Di Benedetto, Maria D.

    2004-01-01

    A general notion of hybrid bisimulation is proposed and related to the notions of algebraic, state-space and input-output equivalences for the class of switching linear systems. An algebraic characterization of hybrid bisimulations and a procedure converging in a finite number of steps to the

  8. Noise analysis of switched integrator preamplifiers

    International Nuclear Information System (INIS)

    Sun Hongbo; Li Yulan; Zhu Weibin

    2004-01-01

    The main noise sources of switched integrator preamplifiers are discussed, and their noise performance are given combined PSpice simulation and experiments on them. Then, some practical methods on how to reduce noise of preamplifiers in two different integrator modes are provided. (authors)

  9. Disturbance Decoupling of Switched Linear Systems

    NARCIS (Netherlands)

    Yurtseven, E.; Heemels, W.P.M.H.; Camlibel, M.K.

    2010-01-01

    In this paper we consider disturbance decoupling problems for switched linear systems. We will provide necessary and sufficient conditions for three different versions of disturbance decoupling, which differ based on which signals are considered to be the disturbance. In the first version the

  10. Modeling of charge switching in ferroelectric capacitors.

    Science.gov (United States)

    Sun, Shunming; Kalkur, Thottam S

    2004-07-01

    To simulate charge switching in ferroelectric capacitors, a pair of exponential growth and decay currents is mapped to the process of polarization reversal. This is based on the fact that these exponential currents [i.e., i = I(m) e(t/tau) (t or = 0)], are completely specified by two constants I(m) and tau and each accommodates an integral charge Q = I(m) x tau. Equating this charge to the remanent spontaneous polarization allows for the modeling of switching current. For practical circuit simulations for charge switching, this modeling of switching current is simplified to an exponential decay current whose integral charge is set equal to the total reversed spontaneous polarization. This is because an exponential decay current can be conveniently implemented by charging a series resistor and capacitor (RC) circuit with a pulse-voltage source. The voltage transitions of the pulse source are associated with the polarization reversal and can be controlled with a noninverting Schmitt trigger that toggles at the positive and negative coercive voltages of a ferroelectric capacitor. The final circuit model incorporates such electrical and geometrical parameters as capacitance, remanent spontaneous polarization, coercive field, electrode area, and film thickness of a ferroelectric, thin-film capacitor.

  11. Modeling A Circuit Switched Multiprocessor Interconnect

    Science.gov (United States)

    1989-10-01

    at stages of the network nearer the memories is artificially elevated. This would tend to make the predicted values for U more pessimistic. 2. In...and by grants from the Sloan foundation and IBM. 2The design currently usam a packet-switched direct network with wormhole routing [l ] although

  12. Q-Switching in a Neodymium Laser

    Science.gov (United States)

    Holgado, Warein; Sola, Inigo J.; Jarque, Enrique Conejero; Jarabo, Sebastian; Roso, Luis

    2012-01-01

    We present a laboratory experiment for advanced undergraduate or graduate laser-related classes to study the performance of a neodymium laser. In the experiment, the student has to build the neodymium laser using an open cavity. After that, the cavity losses are modulated with an optical chopper located inside, so the Q-switching regime is…

  13. Moment switching in nanotube magnetic force probes

    NARCIS (Netherlands)

    Kirtley, J.R.; Deng, Z.; Luan, L.; Yenilmez, E.; Dai, H.; Moler, K.A.

    2007-01-01

    Magnetic images of high density vertically recorded media using metal-coated carbon nanotube tips exhibit a doubling of the spatial frequency under some conditions (Deng et al 2004 Appl. Phys. Lett. 85 6263). Here we demonstrate that this spatial frequency doubling is due to the switching of the

  14. Multiple application coded switch development report

    International Nuclear Information System (INIS)

    Bernal, E.L.; Kestly, J.D.

    1979-03-01

    The development of the Multiple Application Coded Switch (MACS) and its related controller are documented; the functional and electrical characteristics are described; the interface requirements defined, and a troubleshooting guide provided. The system was designed for the Safe Secure Trailer System used for secure transportation of nuclear material

  15. Investment in electricity networks with transmission switching

    DEFF Research Database (Denmark)

    Villumsen, Jonas Christoffer; Philpott, A.B.

    2012-01-01

    allows the solution of large problem instances. The methodology is illustrated by its application to a problem of determining the optimal investment in switching equipment and transmission capacity for an existing network. Computational tests on IEEE test networks with 73 nodes and 118 nodes confirm...

  16. Switching from Computer to Microcomputer Architecture Education

    Science.gov (United States)

    Bolanakis, Dimosthenis E.; Kotsis, Konstantinos T.; Laopoulos, Theodore

    2010-01-01

    In the last decades, the technological and scientific evolution of the computing discipline has been widely affecting research in software engineering education, which nowadays advocates more enlightened and liberal ideas. This article reviews cross-disciplinary research on a computer architecture class in consideration of its switching to…

  17. Balanced truncation for linear switched systems

    DEFF Research Database (Denmark)

    Petreczky, Mihaly; Wisniewski, Rafal; Leth, John-Josef

    2013-01-01

    In this paper, we present a theoretical analysis of the model reduction algorithm for linear switched systems from Shaker and Wisniewski (2011, 2009) and . This algorithm is a reminiscence of the balanced truncation method for linear parameter varying systems (Wood et al., 1996) [3]. Specifically...

  18. Screen captures to support switching attention.

    NARCIS (Netherlands)

    Gellevij, M.R.M.; van der Meij, Hans

    2002-01-01

    The study set out to validate the supportive role of screen captures for switching attention. Forty-two participants learned how to work with Microsoft Excel with a paper manual. There were three types of manuals: a textual manual, a visual manual with full-screen captures, and a visual manual with

  19. A Broadband Ultrathin Nonlinear Switching Metamaterial

    Directory of Open Access Journals (Sweden)

    E. Zarnousheh Farahani

    2017-05-01

    Full Text Available In this paper, an ultrathin planar nonlinear metamaterial slab is designed and simulated. Nonlinearity is provided through placing diodes in each metamaterial unit cell. The diodes are auto-biased and activated by an incident wave. The proposed structure represents a broadband switching property between two transmission and reflection states depending on the intensity of the incident wave. High permittivity values are presented creating a near zero effective impedance at low power states, around the second resonant mode of the structure unit cell; as the result, the incident wave is reflected. Increasing the incident power to the level which can activate the loaded diodes in the structure results in elimination of the resonance and consequently a drop in the permittivity values near the permeability one as well as a switch to the transmission state. A full wave as well as a nonlinear simulations are performed. An optimization method based on weed colonization is applied to the unit cell of the metamaterial slab to achieve the maximum switching bandwidth. The structure represents a 24% switching bandwidth of a 10 dB reduction in the reflection coefficient.

  20. Update of the CERN exchange switches

    CERN Multimedia

    2005-01-01

    In the context of the telephony services improvements, an update of the CERN exchange switches will be performed on Thursday 28 April from 7.00 p.m. until midnight. Disturbances or even disruptions of telephony services may occur during this intervention

  1. Switching Dynamics and the Stress Process

    Science.gov (United States)

    Cornwell, Benjamin

    2013-01-01

    This article shows how maintaining social relationships can be a daily hassle that has implications for the stress process, depending on how often individuals transition, or "switch," between various social roles and social settings throughout the day. I use nationally representative time-diary data on 7,662 respondents from the 2010 American Time…

  2. Sampled Noise in Switched Current Circuits

    DEFF Research Database (Denmark)

    Jørgensen, Ivan Herald Holger; Bogason, Gudmundur

    1997-01-01

    The understanding of noise in analog sampled data systems is vital for the design of high resolution circuitry. In this paper a general description of sampled and held noise is presented. The noise calculations are verified by measurements on an analog delay line implemented using switched...

  3. Noise Analysis of Switched-Current Circuits

    DEFF Research Database (Denmark)

    Jørgensen, Ivan Harald Holger; Bogason, Gudmundur

    1998-01-01

    The understanding of noise in analog sampled data systems is vital for the design of high resolution circuitry. In this paper a general description of sampled and held noise is presented. The noise calculations are verified by measurements on an analog delay line implemented using switched...

  4. Your Light Switch Is Your Vote

    DEFF Research Database (Denmark)

    McIlvenny, Paul

    (mediational means) the simple act of switching off the lights and the consequences of such an act; (b) the massive infrastructure of communication to synchronise the collective performance of a global ‘climate public’; (c) the discursive ‘memory work’ to archive and memorialise the hour, eg. on YouTube...

  5. Switched reluctance motor optimal geometry design

    Directory of Open Access Journals (Sweden)

    Liviu Neamt

    2010-12-01

    Full Text Available This paper deals with the Switched Reluctance Motor (SRM analysis using Finite Element Method (FEM for geometrical optimization in terms of volume ratio of torque on the rotor, the so-called specific torque. The optimization parameter is the pair: stator and rotor pole angles, which forms a crucial part of the design process.

  6. Prey switching behaviour in the planktonic copepod Acartia tonsa

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Saiz, E.; Viitasalo, M.

    1996-01-01

    The copepod Acartia tonsa has 2 different prey encounter strategies. It can generate a feeding current to encounter and capture immobile prey (suspension feeding) or it can sink slowly and perceive motile prey by means of mechanoreceptors on the antennae (ambush feeding). We hypothesized that A....... tonsa adopts the feeding mode that generates the highest energy intake rate; i.e. that prey selection changes according to the relative concentrations of alternative prey (prey switching) and that the copepods spend disproportionately more time in the feeding mode that provides the greatest reward....... Based on earlier observations, we also hypothesized that turbulence changes food selection towards motile prey. We tested these hypotheses by examining feeding rates and behaviour in adult females of A. tonsa feeding in mixtures of 2 prey organisms, a diatom (Thalassiosira weissflogii) and a ciliate...

  7. Relatively slow stochastic gene-state switching in the presence of positive feedback significantly broadens the region of bimodality through stabilizing the uninduced phenotypic state.

    Science.gov (United States)

    Ge, Hao; Wu, Pingping; Qian, Hong; Xie, Xiaoliang Sunney

    2018-03-01

    Within an isogenic population, even in the same extracellular environment, individual cells can exhibit various phenotypic states. The exact role of stochastic gene-state switching regulating the transition among these phenotypic states in a single cell is not fully understood, especially in the presence of positive feedback. Recent high-precision single-cell measurements showed that, at least in bacteria, switching in gene states is slow relative to the typical rates of active transcription and translation. Hence using the lac operon as an archetype, in such a region of operon-state switching, we present a fluctuating-rate model for this classical gene regulation module, incorporating the more realistic operon-state switching mechanism that was recently elucidated. We found that the positive feedback mechanism induces bistability (referred to as deterministic bistability), and that the parameter range for its occurrence is significantly broadened by stochastic operon-state switching. We further show that in the absence of positive feedback, operon-state switching must be extremely slow to trigger bistability by itself. However, in the presence of positive feedback, which stabilizes the induced state, the relatively slow operon-state switching kinetics within the physiological region are sufficient to stabilize the uninduced state, together generating a broadened parameter region of bistability (referred to as stochastic bistability). We illustrate the opposite phenotype-transition rate dependence upon the operon-state switching rates in the two types of bistability, with the aid of a recently proposed rate formula for fluctuating-rate models. The rate formula also predicts a maximal transition rate in the intermediate region of operon-state switching, which is validated by numerical simulations in our model. Overall, our findings suggest a biological function of transcriptional "variations" among genetically identical cells, for the emergence of bistability and

  8. Switching Between Infliximab Originator and Biosimilar in Paediatric Patients with Inflammatory Bowel Disease. Preliminary Observations.

    Science.gov (United States)

    Sieczkowska, J; Jarzębicka, D; Banaszkiewicz, A; Plocek, A; Gawronska, A; Toporowska-Kowalska, E; Oracz, G; Meglicka, M; Kierkus, J

    2016-02-01

    The growing incidence of inflammatory bowel disease (IBD) in children necessitates the use of biological treatments. Recently, an infliximab biosimilar was authorized in the European Union, which may result in switching patients. We present our preliminary experiences with such switches. The prospective study included 32 paediatric patients diagnosed with Crohn's disease (CD) and 7 children with ulcerative colitis (UC) at 3 academic hospitals, who were switched from infliximab originator to its biosimilar (Remsima). Patient characteristics, disease severity, laboratory parameters and adverse events were recorded. Means, medians and ranges were calculated. Mean age at diagnosis of CD and UC was 11.1 (2.7-15.3) and 12.3 years (8.5-14.8), respectively. Mean number of infliximab originator infusions before switching to the biosimilar was 9.9 (median 8, range 4-29) and 5.1 (5, 1-12) for the CD and UC group, respectively. Evaluation efficacy of last biosimilar doses of all patients revealed rates of clinical remission of 88 and 57% for CD and UC patients, respectively. Last follow-up assessment of patients who continued with biosimilar therapy showed that 16/20 (80%) CD patients and all 4 UC individuals were in remission. One infusion reaction to infliximab biosimilar was observed in a CD patient, which led to treatment discontinuation. The incidence of sporadic mild adverse events prior to and after switching did not differ significantly and was consistent with the safety profile of the infliximab molecule. Switching from infliximab originator to its biosimilar seems to be a safe option in children with CD. After the switch the biosimilar was just as effective as the originator. Copyright © 2015 European Crohn’s and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  9. Binomial tree method for pricing a regime-switching volatility stock loans

    Science.gov (United States)

    Putri, Endah R. M.; Zamani, Muhammad S.; Utomo, Daryono B.

    2018-03-01

    Binomial model with regime switching may represents the price of stock loan which follows the stochastic process. Stock loan is one of alternative that appeal investors to get the liquidity without selling the stock. The stock loan mechanism resembles that of American call option when someone can exercise any time during the contract period. From the resembles both of mechanism, determination price of stock loan can be interpreted from the model of American call option. The simulation result shows the behavior of the price of stock loan under a regime-switching with respect to various interest rate and maturity.

  10. Formulation of a generalised switching CFAR with application to X-band maritime surveillance radar.

    Science.gov (United States)

    Weinberg, Graham V

    2015-01-01

    A generalisation of a switching based detector is examined, allowing the construction of such detectors for target detection in any clutter model of interest. Such detectors are important in radar signal processing because they are robust solutions to the management of interference. Although formulated in general terms, the theory is applied to the design of a switching constant false alarm rate detector for X-band maritime surveillance radar. It is shown that such a detector manages the problem of interference better than standard detection processes.

  11. Reconfigurable radio-over-fiber system based on optical switch and tunable filter

    Science.gov (United States)

    Li, Xiao; Yin, Rui; Ji, Wei; Sun, Kai; Zhang, Shicheng

    2017-09-01

    As the best candidate for wireless-access networks, radio-over-fiber (RoF) technology can carry a variety of business. It is necessary to provide differentiated services for different users, so the network needs to produce signals with different modulation formats and different frequencies. A reconfigurable RoF system based on a switch and tunable optical filter that can realize modulation format conversion and multiple frequency signal switching functions is designed. It has a good performance in terms of bit error rate and an eye diagram. The design can help to use radio frequency resources efficiently and make dynamic bandwidth resources controllable.

  12. Metal impurity injection into DIVA plasmas with a Q-switched laser beam

    International Nuclear Information System (INIS)

    Yamauchi, Toshihiko; Nagami, Masayuki; Sengoku, Seio; Kumagai, Katsuaki

    1978-08-01

    Metal impurity injection into DIVA plasmas with a Q-switched ruby laser beam is described. Metal materials used are aluminium and gold. The Q-switched laser beam is incident onto a thin metal film thickness about 0.2 μm coated on pyrex glass plate surface. The metal film is vaporized by the laser beam and injected into DIVA plasma. The laser-beam injection method has advantages of sharp profile of vaporized metal, easy control of vaporized metal quantity and injection rate control of metal vapor. (author)

  13. Progress in switching technology for METS systems

    International Nuclear Information System (INIS)

    Honig, E.M.; Swannack, C.E.; Warren, R.W.; Whitaker, D.H.

    1977-01-01

    Three distinct sets of switching requirements have emerged from design optimization studies of large superconducting magnetic energy storage systems, such as the METS system to power the adiabatic plasma compression field in the proposed theta-pinch SFTR. Extremely low joule loss cryogenic disconnects are required between storage coils in the liquid helium environment to allow charging the coils in series over a prolonged time, then to isolate the coils for parallel fast discharging into the load. Another switch must break the current in the series charging loop and absorb the energy from the stray inductance. This action will allow the subsequent opening of the cryogenic disconnects under near zero current condition. The current now has been transferred to the many paralleled circuits, each containing a high current, high voltage interrupter. The opening and arc commutation of the interrupter starts the energy transfer into the load. The primary activities associated with cryogenic disconnect have been testing and development of contact materials, configurations, and closing forces for carrying 26 kA with a resistance less than 40 nΩ, and development of an actuating system that is both reliable and fast acting in a liquid helium environment. The charging loop switch will include a continuous duty switch and a vacuum interrupter. The continuous duty switch resistance can be an order of magnitude larger than that of the cryogenic disconnect because it does not present a refrigeration load. The HVDC interrupter must break 26 kA and withstand 60 kV during the energy transfer time of 700 μs. Testing in progress already has shown successful interruption using single vacuum interrupters up to 31 kA and 66 kV

  14. Trend Switching Processes in Financial Markets

    Science.gov (United States)

    Preis, Tobias; Stanley, H. Eugene

    For an intriguing variety of switching processes in nature, the underlying complex system abruptly changes at a specific point from one state to another in a highly discontinuous fashion. Financial market fluctuations are characterized by many abrupt switchings creating increasing trends ("bubble formation") and decreasing trends ("bubble collapse"), on time scales ranging from macroscopic bubbles persisting for hundreds of days to microscopic bubbles persisting only for very short time scales. Our analysis is based on a German DAX Future data base containing 13,991,275 transactions recorded with a time resolution of 10- 2 s. For a parallel analysis, we use a data base of all S&P500 stocks providing 2,592,531 daily closing prices. We ask whether these ubiquitous switching processes have quantifiable features independent of the time horizon studied. We find striking scale-free behavior of the volatility after each switching occurs. We interpret our findings as being consistent with time-dependent collective behavior of financial market participants. We test the possible universality of our result by performing a parallel analysis of fluctuations in transaction volume and time intervals between trades. We show that these financial market switching processes have features similar to those present in phase transitions. We find that the well-known catastrophic bubbles that occur on large time scales - such as the most recent financial crisis - are no outliers but in fact single dramatic representatives caused by the formation of upward and downward trends on time scales varying over nine orders of magnitude from the very large down to the very small.

  15. Operation of a homeostatic sleep switch.

    Science.gov (United States)

    Pimentel, Diogo; Donlea, Jeffrey M; Talbot, Clifford B; Song, Seoho M; Thurston, Alexander J F; Miesenböck, Gero

    2016-08-18

    Sleep disconnects animals from the external world, at considerable risks and costs that must be offset by a vital benefit. Insight into this mysterious benefit will come from understanding sleep homeostasis: to monitor sleep need, an internal bookkeeper must track physiological changes that are linked to the core function of sleep. In Drosophila, a crucial component of the machinery for sleep homeostasis is a cluster of neurons innervating the dorsal fan-shaped body (dFB) of the central complex. Artificial activation of these cells induces sleep, whereas reductions in excitability cause insomnia. dFB neurons in sleep-deprived flies tend to be electrically active, with high input resistances and long membrane time constants, while neurons in rested flies tend to be electrically silent. Correlative evidence thus supports the simple view that homeostatic sleep control works by switching sleep-promoting neurons between active and quiescent states. Here we demonstrate state switching by dFB neurons, identify dopamine as a neuromodulator that operates the switch, and delineate the switching mechanism. Arousing dopamine caused transient hyperpolarization of dFB neurons within tens of milliseconds and lasting excitability suppression within minutes. Both effects were transduced by Dop1R2 receptors and mediated by potassium conductances. The switch to electrical silence involved the downregulation of voltage-gated A-type currents carried by Shaker and Shab, and the upregulation of voltage-independent leak currents through a two-pore-domain potassium channel that we term Sandman. Sandman is encoded by the CG8713 gene and translocates to the plasma membrane in response to dopamine. dFB-restricted interference with the expression of Shaker or Sandman decreased or increased sleep, respectively, by slowing the repetitive discharge of dFB neurons in the ON state or blocking their entry into the OFF state. Biophysical changes in a small population of neurons are thus linked to the

  16. Interconnecting network for switching data packets and method for switching data packets

    Science.gov (United States)

    Benner, Alan Frederic; Minkenberg, Cyriel Johan Agnes; Stunkel, Craig Brian

    2010-05-25

    The interconnecting network for switching data packets, having data and flow control information, comprises a local packet switch element (S1) with local input buffers (I(1,1) . . . I(1,y)) for buffering the incoming data packets, a remote packet switch element (S2) with remote input buffers (I(2,1) . . . I(2,y)) for buffering the incoming data packets, and data lines (L) for interconnecting the local and the remote packet switch elements (S1, S2). The interconnecting network further comprises a local and a remote arbiter (A1, A2) which are connected via control lines (CL) to the input buffers (I(1,1) . . . I(1,y), I(2,1) . . . I(2,y)), and which are formed such that they can provide that the flow control information is transmitted via the data lines (L) and the control lines (CL).

  17. Rotor position sensor switches currents in brushless dc motors

    Science.gov (United States)

    1965-01-01

    Reluctance switch incorporated in an induction motor is used for sensing rotor position and switching armature circuits in a brushless dc motor. This device drives the solar array system of an unmanned space satellite.

  18. An optimal multiple switching problem under weak assumptions

    Directory of Open Access Journals (Sweden)

    Imen Hassairi

    2017-10-01

    Full Text Available This work studies the problem of optimal multiple switching in finite horizon, when the switching costs functions are continous and belong to class D. This problem is solved by means of the Snell envelope of processes.

  19. The landscape of isoform switches in human cancers

    DEFF Research Database (Denmark)

    Vitting-Seerup, Kristoffer; Sandelin, Albin Gustav

    2017-01-01

    developed methods for identification and visualization of isoform switches with predicted functional consequences. Using these methods, we characterized isoform switching in RNA-seq data from >5,500 cancer patients covering 12 solid cancer types. Isoform switches with potential functional consequences were...... common, affecting approximately 19% of multiple transcript genes. Among these, isoform switches leading to loss of DNA sequence encoding protein domains were more frequent than expected, particularly in pancancer switches. We identified several isoform switches as powerful biomarkers: 31 switches were...... highly predictive of patient survival independent of cancer types. Our data constitute an important resource for cancer researchers, available through interactive web tools. Moreover, our methods, available as an R package, enable systematic analysis of isoform switches from other RNA-seq datasets...

  20. Multilevel inverter switching controller using a field programmable ...

    African Journals Online (AJOL)

    Conducted simulation and measurement results verified and validated the switching controller design functionality and requirement. Keywords: multilevel inverter, switching controller; FPGA, general purpose processor (GPP);digital signal processing (DSP); IGBT; Verilog, power consumption; harmonic elimination (SHE).

  1. Generic switching of warfarin and risk of excessive anticoagulation

    DEFF Research Database (Denmark)

    Hellfritzsch, Maja; Rathe, Jette; Stage, Tore Bjerregaard

    2016-01-01

    PURPOSE: Generic switching of warfarin was recently repealed in Denmark, as adverse drug reaction (ADR) reports suggested risk of excessive anticoagulation following switches from branded to generic warfarin. We investigated this putative association in a formalized pharmacoepidemiological analys...

  2. Development of SWITCH-Hawaii model: loads and renewable resources.

    Science.gov (United States)

    2016-08-01

    This report summarizes work done to configure the SWITCH power system model using data for the Oahu power system. SWITCH is a planning model designed to choose optimal infrastructure investments for power systems over a multi-decade period. Investmen...

  3. Language attrition and code-switching among US Americans in ...

    African Journals Online (AJOL)

    switching in immigration contexts is the ... of code-switching, which is socially motivated, and language attrition, which is predominantly a psycholinguistic issue, ..... had a child no you were studying? To emphasize a point, focus, show contrast, quote.

  4. Perturbative effects on ultra-short soliton self-switching

    Indian Academy of Sciences (India)

    short soliton self-switching. AMARENDRA K SARMA. 1,∗ and AJIT KUMAR. 2. 1. Department of ... Abstract. A numerical study of ultra-short self-soliton switching along with the corre- ..... improving the presentation of our work. References.

  5. Integrated Optoelectronic Switching Technology for Fiber-Optic Communications Networks

    National Research Council Canada - National Science Library

    Fan, Regis

    1998-01-01

    .... most of the effort in optical amplifier switch modules have been focused on monolithic switches in which the entire device is fabricated on an InP substrate together with the semiconductor optical amplifiers (SOAs...

  6. A fundamental trade-off in covalent switching and its circumvention by enzyme bifunctionality in glucose homeostasis.

    Science.gov (United States)

    Dasgupta, Tathagata; Croll, David H; Owen, Jeremy A; Vander Heiden, Matthew G; Locasale, Jason W; Alon, Uri; Cantley, Lewis C; Gunawardena, Jeremy

    2014-05-09

    Covalent modification provides a mechanism for modulating molecular state and regulating physiology. A cycle of competing enzymes that add and remove a single modification can act as a molecular switch between "on" and "off" and has been widely studied as a core motif in systems biology. Here, we exploit the recently developed "linear framework" for time scale separation to determine the general principles of such switches. These methods are not limited to Michaelis-Menten assumptions, and our conclusions hold for enzymes whose mechanisms may be arbitrarily complicated. We show that switching efficiency improves with increasing irreversibility of the enzymes and that the on/off transition occurs when the ratio of enzyme levels reaches a value that depends only on the rate constants. Fluctuations in enzyme levels, which habitually occur due to cellular heterogeneity, can cause flipping back and forth between on and off, leading to incoherent mosaic behavior in tissues, that worsens as switching becomes sharper. This trade-off can be circumvented if enzyme levels are correlated. In particular, if the competing catalytic domains are on the same protein but do not influence each other, the resulting bifunctional enzyme can switch sharply while remaining coherent. In the mammalian liver, the switch between glycolysis and gluconeogenesis is regulated by the bifunctional 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2). We suggest that bifunctionality of PFK-2/FBPase-2 complements the metabolic zonation of the liver by ensuring coherent switching in response to insulin and glucagon.

  7. Field-Distortion Air-Insulated Switches for Next-Generation Pulsed-Power Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Wisher, Matthew Louis [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Johns, Owen M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Breden, Eric Wayne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Calhoun, Jacob Daniel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gruner, Frederick Rusticus [Kinetech LLC, Cedar Crest, NM (United States); Hohlfelder, Robert James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mulville, Thomas D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Muron, David J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stoltzfus, Brian S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stygar, William A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    We have developed two advanced designs of a field-distortion air-insulated spark-gap switch that reduce the size of a linear-transformer-driver (LTD) brick. Both designs operate at 200 kV and a peak current of ~50 kA. At these parameters, both achieve a jitter of less than 2 ns and a prefire rate of ~0.1% over 5000 shots. We have reduced the number of switch parts and assembly steps, which has resulted in a more uniform, design-driven assembly process. We will characterize the performance of tungsten-copper and graphite electrodes, and two different electrode geometries. The new switch designs will substantially improve the electrical and operational performance of next-generation pulsed-power accelerators.

  8. Microscopic observation of zenithal bistable switching in nematic devices with different surface relief structures

    International Nuclear Information System (INIS)

    Uche, C; Elston, S J; Parry-Jones, L A

    2005-01-01

    Nematic liquid crystals have been shown to exhibit zenithal electro-optic bistability in devices containing sinusoidal and deformed sinusoidal gratings. Recently it has been shown that zenithal bistable states can also be supported at isolated edges of square gratings. In this paper, we present microscopic observations of bistability in cells containing sinusoidal gratings and long-pitch square gratings. We have also investigated a novel display based on square wells. High frame-rate video microscopy was used to obtain time-sequenced images when the devices were switched with monopolar pulses. These show that zenithal bistable switching can occur by two different processes: (i) domain growth (observed in cells containing sinusoidal gratings) and (ii) homogenous switching (observed in cells containing isolated edges

  9. A systematic method of smooth switching LPV controllers design for a morphing aircraft

    Directory of Open Access Journals (Sweden)

    Jiang Weilai

    2015-12-01

    Full Text Available This paper is concerned with a systematic method of smooth switching linear parameter-varying (LPV controllers design for a morphing aircraft with a variable wing sweep angle. The morphing aircraft is modeled as an LPV system, whose scheduling parameter is the variation rate of the wing sweep angle. By dividing the scheduling parameter set into subsets with overlaps, output feedback controllers which consider smooth switching are designed and the controllers in overlapped subsets are interpolated from two adjacent subsets. A switching law without constraint on the average dwell time is obtained which makes the conclusion less conservative. Furthermore, a systematic algorithm is developed to improve the efficiency of the controllers design process. The parameter set is divided into the fewest subsets on the premise that the closed-loop system has a desired performance. Simulation results demonstrate the effectiveness of this approach.

  10. The switching-activity estimation of SAD engine for video coding systems

    Science.gov (United States)

    Lee, Yu-Hsuan; Wu, Tsai-Hsing

    2014-10-01

    The sum of absolute difference (SAD) is generally adopted as a cost function in motion estimation (ME) and temporal error concealment (TEC) algorithm owing to its efficiency. The hardware architecture of SAD also consumes considerable power dissipation in video codec chip. Hence, the switching-activity analysis on SAD is quite essential from algorithm/architecture perspectives. This work develops the estimation formulas for switching-activity dedicated for SAD engine according to probability theory. The experiment results reveal that the probability error rate (PER) of the SAD engine is as minor as 5.61%. Consequently, this leads to a precise switching-activity estimation of the SAD-based algorithm/architecture for video signal processing.

  11. Ab initio theory for current-induced molecular switching: Melamine on Cu(001)

    KAUST Repository

    Ohto, Tatsuhiko

    2013-05-28

    Melamine on Cu(001) is mechanically unstable under the current of a scanning tunneling microscope tip and can switch among configurations. However, these are not equally accessible, and the switching critical current depends on the bias polarity. In order to explain such rich phenomenology, we have developed a scheme to evaluate the evolution of the reaction paths and activation barriers as a function of bias, which is rooted in the nonequilibrium Green\\'s function method implemented within density functional theory. This, combined with the calculation of the inelastic electron tunneling spectroscopy signal, allows us to identify the vibrational modes promoting the observed molecular conformational changes. Finally, once our ab initio results are used within a resonance model, we are able to explain the details of the switching behavior, such as its dependence on the bias polarity, and the noninteger power relation between the reaction rate constants and both the bias voltage and the electric current. © 2013 American Physical Society.

  12. Analysis of novel stochastic switched SILI epidemic models with continuous and impulsive control

    Science.gov (United States)

    Gao, Shujing; Zhong, Deming; Zhang, Yan

    2018-04-01

    In this paper, we establish two new stochastic switched epidemic models with continuous and impulsive control. The stochastic perturbations are considered for the natural death rate in each equation of the models. Firstly, a stochastic switched SILI model with continuous control schemes is investigated. By using Lyapunov-Razumikhin method, the sufficient conditions for extinction in mean are established. Our result shows that the disease could be die out theoretically if threshold value R is less than one, regardless of whether the disease-free solutions of the corresponding subsystems are stable or unstable. Then, a stochastic switched SILI model with continuous control schemes and pulse vaccination is studied. The threshold value R is derived. The global attractivity of the model is also obtained. At last, numerical simulations are carried out to support our results.

  13. On-chip switch for reconfigurable mode-multiplexing optical network.

    Science.gov (United States)

    Sun, Chunlei; Yu, Yu; Chen, Guanyu; Zhang, Xinliang

    2016-09-19

    The switching and routing is essential for an advanced and reconfigurable optical network, and great efforts have been done for traditional single-mode system. We propose and demonstrate an on-chip switch compatible with mode-division multiplexing system. By controlling the induced phase difference, the functionalities of dynamically routing data channels can be achieved. The proposed switch is experimentally demonstrated with low insertion loss of ~1 dB and high extinction ratio of ~20 dB over the C-band for OFF-ON switchover. For further demonstration, the non-return-to-zero on-off keying signals at 10 Gb/s carried on the two spatial modes are successfully processed. Open and clear eye diagrams can be observed and the bit error rate measurements indicate a good data routing performance.

  14. Stability analysis of linear switching systems with time delays

    International Nuclear Information System (INIS)

    Li Ping; Zhong Shouming; Cui Jinzhong

    2009-01-01

    The issue of stability analysis of linear switching system with discrete and distributed time delays is studied in this paper. An appropriate switching rule is applied to guarantee the stability of the whole switching system. Our results use a Riccati-type Lyapunov functional under a condition on the time delay. So, switching systems with mixed delays are developed. A numerical example is given to illustrate the effectiveness of our results.

  15. Photonics in switching: enabling technologies and subsystem design

    DEFF Research Database (Denmark)

    Vlachos, K.; Raffaelli, C.; Aleksic, S.

    2009-01-01

    This paper describes recent research activities and results in the area of photonic switching carried out within the framework of the EU-funded e-Photon/ONe + network of excellence, Virtual Department on Optical Switching. Technology aspects of photonics in switching and, in particular, recent...... advances in wavelength conversion, ring resonators, and packet switching and processing subsystems are presented as the building blocks for the implementation of a high-performance router for the next-generation Internet....

  16. Contraceptive discontinuation and switching among couples receiving integrated HIV and family planning services in Lusaka, Zambia.

    Science.gov (United States)

    Haddad, Lisa; Wall, Kristin M; Vwalika, Bellington; Khu, Naw Htee; Brill, Ilene; Kilembe, William; Stephenson, Rob; Chomba, Elwyn; Vwalika, Cheswa; Tichacek, Amanda; Allen, Susan

    2013-10-01

    To describe predictors of contraceptive method discontinuation and switching behaviours among HIV-positive couples receiving couples' voluntary HIV counselling and testing services in Lusaka, Zambia. Couples were randomized in a factorial design to two-family planning educational intervention videos, received comprehensive family planning services and were assessed every 3 months for contraceptive initiation, discontinuation and switching. We modelled factors associated with contraceptive method upgrading and downgrading via multivariate Andersen-Gill models. Most women continued the initial method selected after randomization. The highest rates of discontinuation/switching were observed for injectable contraceptive and intrauterine device users. Time to discontinuing the more effective contraceptive methods or downgrading to oral contraceptives or condoms was associated with the women's younger age, desire for more children within the next year, heavy menstrual bleeding, bleeding between periods and cystitis/dysuria. Health concerns among women about contraceptive implants and male partners not wanting more children were associated with upgrading from oral contraceptives or condoms. HIV status of the woman or the couple was not predictive of switching or stopping. We found complicated patterns of contraceptive use. The predictors of contraception switching indicate that interventions targeted to younger couples that address common contraception-related misconceptions could improve effective family planning utilization. We recommend these findings be used to increase the uptake and continuation of contraception, especially long-acting reversible contraceptive (LARC) methods, and that fertility goal based, LARC-focused family planning be offered as an integral part of HIV prevention services.

  17. Contraceptive discontinuation and switching among couples receiving integrated HIV and family planning services in Lusaka, Zambia

    Science.gov (United States)

    Haddad, Lisa; Wall, Kristin M; Vwalika, Bellington; Htee Khu, Naw; Brill, Ilene; Kilembe, William; Stephenson, Rob; Chomba, Elwyn; Vwalika, Cheswa; Tichacek, Amanda; Allen, Susan

    2014-01-01

    Objective To describe predictors of contraceptive method discontinuation and switching behaviors among HIV positive couples receiving couples' voluntary HIV counseling and testing services in Lusaka, Zambia. Design Couples were randomized in a factorial design to two family planning educational intervention videos, received comprehensive family planning services, and were assessed every 3-months for contraceptive initiation, discontinuation and switching. Methods We modeled factors associated with contraceptive method upgrading and downgrading via multivariate Andersen-Gill models. Results Most women continued the initial method selected after randomization. The highest rates of discontinuation/switching were observed for injectable contraceptive and intrauterine device users. Time to discontinuing the more effective contraceptive methods or downgrading to oral contraceptives or condoms was associated with the women's younger age, desire for more children within the next year, heavy menstrual bleeding, bleeding between periods, and cystitis/dysuria. Health concerns among women about contraceptive implants and male partners not wanting more children were associated with upgrading from oral contraceptives or condoms. HIV status of the woman or the couple was not predictive of switching or stopping. Conclusions We found complicated patterns of contraceptive use. The predictors of contraception switching indicate that interventions targeted to younger couples that address common contraception-related misconceptions could improve effective family planning utilization. We recommend these findings be used to increase the uptake and continuation of contraception, especially long acting reversible contraceptive (LARC) methods, and that fertility-goal based, LARC-focused family planning be offered as an integral part of HIV prevention services. PMID:24088689

  18. Switching health insurers: the role of price, quality and consumer information search.

    Science.gov (United States)

    Boonen, Lieke H H M; Laske-Aldershof, Trea; Schut, Frederik T

    2016-04-01

    We examine the impact of price, service quality and information search on people's propensity to switch health insurers in the competitive Dutch health insurance market. Using panel data from annual household surveys and data on health insurers' premiums and quality ratings over the period 2006-2012, we estimate a random effects logit model of people's switching decisions. We find that switching propensities depend on health plan price and quality, and on people's age, health, education and having supplementary or group insurance. Young people (18-35 years) are more sensitive to price, whereas older people are more sensitive to quality. Searching for health plan information has a much stronger impact on peoples' sensitivity to price than to service quality. In addition, searching for health plan information has a stronger impact on the switching propensity of higher than lower educated people, suggesting that higher educated people make better use of available health plan information. Finally, having supplementary insurance significantly reduces older people's switching propensity.

  19. Improved HPLC column-switching determination of Coenzyme Q and Vitamin E in plasma.

    Science.gov (United States)

    Bompadre, Stefano; Tulipani, Sara; Romandini, Stefania; Giorgetti, Raffaele; Battino, Maurizio

    2008-01-01

    A novel isocratic modified column-switching HPLC method for automated quantitative analysis of Vitamin E and Coenzyme Q, in the reduced and oxidized form, is described. Many column-switching HPLC methods are found in the literature, also for determining antioxidant substances, but we developed a different system of column-switching. An empty column, 5 cm long, was connected to the switching valve, before the sample loop and the extraction column. The sample loop was connected directly after the empty column. The inserted column, containing about 1.4 ml of the extraction eluent simulated a gradient elution, enhancing sensitivity and resolution. When switching the columns, the empty column is placed right before the extraction column and acts as a static mixer for the extraction phase and the incoming analytical phase. Samples were cleaned from interfering compounds by transfer onto a extraction-column, using a C-8 silica. Separation was performed onto an analytical column C18 3 m icrom, 150 mm x 4.6 mm at a flow rate of 1.0 ml/min with 20 mmol/l lithium perchlorate/perchloric acid, pH3.0 in Ethanol as analytical eluent. Detection was performed with a ESA Coulochem 5100 A model. The method was found to be suitable for automated analysis of Coenzyme Q, reduced and oxidized form, and Vitamin E in serum.

  20. Methodology, Measurement and Analysis of Flow Table Update Characteristics in Hardware OpenFlow Switches

    KAUST Repository

    Kuźniar, Maciej

    2018-02-15

    Software-Defined Networking (SDN) and OpenFlow are actively being standardized and deployed. These deployments rely on switches that come from various vendors and differ in terms of performance and available features. Understanding these differences and performance characteristics is essential for ensuring successful and safe deployments.We propose a systematic methodology for SDN switch performance analysis and devise a series of experiments based on this methodology. The methodology relies on sending a stream of rule updates, while relying on both observing the control plane view as reported by the switch and probing the data plane state to determine switch characteristics by comparing these views. We measure, report and explain the performance characteristics of flow table updates in six hardware OpenFlow switches. Our results describing rule update rates can help SDN designers make their controllers efficient. Further, we also highlight differences between the OpenFlow specification and its implementations, that if ignored, pose a serious threat to network security and correctness.

  1. A sealed-off double-gap pseudospark switch and its performance analysis

    Science.gov (United States)

    Lamba, R. P.; Pal, U. N.; Meena, B. L.; Prakash, R.

    2018-03-01

    This paper reports the development of a sealed-off double-gap pseudospark switch and its performance analysis. The modular pseudospark geometry has two gaps that are separated by a cavity drift space region. It utilizes a single ferroelectric trigger unit in a hollow cathode region of the first gap to initiate the discharge for rapid breakdown of both the gaps. The switch has been pinched for deuterium gas and a gas reservoir has been used for maintaining optimum gas pressure in the sealed-off device. The switch design has been analyzed for higher hold-off voltage with high charge transfer capability at higher repetition rates. The developed switch holds a 50 kV voltage in vacuum, and 40 kV during gas discharge at optimum gas pressure with a peak anode current of 8 kA and pulse duration of 1.3 μs while it is operated with a resistive load of 2.9 Ω. The switch has been tested using a constant current charging power supply for pulse repetition frequency up to 50 Hz at different voltages and peak currents corresponding to 200 nF energy storage capacitors. Its performance has been analyzed in terms of pulse parameters including hold-off voltage, jitter, fall time, rise time, peak current and delay time to qualify the design.

  2. Temperature effects on the switching kinetics of a Cu-Ta2O5-based atomic switch.

    Science.gov (United States)

    Tsuruoka, Tohru; Terabe, Kazuya; Hasegawa, Tsuyoshi; Aono, Masakazu

    2011-06-24

    Voltage-current (I-V) measurements in a wide temperature range from 88 to 573 K demonstrated the effects of temperature on the switching behavior of a Cu/Ta(2)O(5)/Pt resistive memory cell that is referred to as a gapless-type atomic switch. After the forming process, the cells were SET from the OFF state to the ON state at a positive bias to the Cu electrode and then RESET from the ON state to the OFF state at a negative bias. In a previous study (Tsuruoka et al 2010 Nanotechnology 21 425205), it was demonstrated that the SET process corresponds to the reformation of a metal filament between the electrodes by the inhomogeneous nucleation and subsequent growth of Cu whereas the RESET process can be attributed to the Joule-heating-assisted dissolution of the metal filament. In the work described here, we observed that the voltages at which the cells are SET and RESET (SET and RESET voltages) decreased in magnitude with an increase in temperature. From calculations of the nucleation rate of Cu nuclei based on the classical nucleation theory, it was found that the observed temperature variation of the SET voltage is primarily determined by supersaturation in the vicinity of the Pt electrode, which is controlled by the application of positive bias. The supersaturation required for spontaneous growth of a Cu nucleus decreases with increasing temperature, resulting in lower SET voltages at higher temperatures. The RESET voltage is determined by the thermal stability of the metal filament formed. Moreover, using the temperature variation in cell resistances of the ON state, the growth speed of the Cu nucleus after the nucleation was found to decease with increasing temperature. These results are consistent with our switching model.

  3. Robust random number generation using steady-state emission of gain-switched laser diodes

    International Nuclear Information System (INIS)

    Yuan, Z. L.; Lucamarini, M.; Dynes, J. F.; Fröhlich, B.; Plews, A.; Shields, A. J.

    2014-01-01

    We demonstrate robust, high-speed random number generation using interference of the steady-state emission of guaranteed random phases, obtained through gain-switching a semiconductor laser diode. Steady-state emission tolerates large temporal pulse misalignments and therefore significantly improves the interference quality. Using an 8-bit digitizer followed by a finite-impulse-response unbiasing algorithm, we achieve random number generation rates of 8 and 20 Gb/s, for laser repetition rates of 1 and 2.5 GHz, respectively, with a ±20% tolerance in the interferometer differential delay. We also report a generation rate of 80 Gb/s using partially phase-correlated short pulses. In relation to the field of quantum key distribution, our results confirm the gain-switched laser diode as a suitable light source, capable of providing phase-randomized coherent pulses at a clock rate of up to 2.5 GHz.

  4. Quantum switching networks: Unicast and multicast

    Science.gov (United States)

    Shukla, Manish Kumar

    Quantum switching networks are analogs of classical switching networks in which classical switches are replaced by quantum switches. These networks are used to switch quantum data among a set of quantum sources and receivers. They can also be used to efficiently switch classical data, and help overcome some limitations of classical switching networks by utilizing the unique properties of quantum information systems, such as superposition and parallelism. In this thesis, we design several such networks which can be broadly put in the following three categories: (1) Quantum unicast networks : We give the design of quantum Baseline network (QBN) which is a self-routing and unicast quantum packet switch that uses the Baseline topology. The classical version of the network blocks packets internally even when there are no output contentions and each input packet is addressed to a different output. The QBN uses the principles of quantum superposition and parallelism to overcome such blocking. Also, for assignments that have multiple input packets addressed to an output, this network creates a quantum superposition of all these packets on that output, ensuring that all packets have non-zero probabilities of being observed on that output. (2) Quantum concentrators : We introduce a new network called quantum concentrator, which is a key component of our quantum multicasting network design. This concentrator is also an n x n quantum switching network, to be denoted by n-QC, and which, for any m, 1 ≤ m ≤ n, routes arbitrary quantum states on any m of its inputs to its top m outputs. This network uses O( n log n) quantum gates, and has a gate level depth of O(log2 n). We also give several variations of this network, the main ones being orderpreserving and priority quantum concentrators. (3) Quantum multicast networks: We first design a quantum multicasting network, called a generalized quantum connector (GQC) which can be used to multicast quantum information from n input

  5. 49 CFR 236.14 - Spring switch signal protection; requirements.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Spring switch signal protection; requirements. 236... Rules and Instructions: All Systems General § 236.14 Spring switch signal protection; requirements. (a... track signaled for movements in only one direction through a spring switch in automatic block signal...

  6. Validating an infrared thermal switch as a novel access technology

    Directory of Open Access Journals (Sweden)

    Memarian Negar

    2010-08-01

    Full Text Available Abstract Background Recently, a novel single-switch access technology based on infrared thermography was proposed. The technology exploits the temperature differences between the inside and surrounding areas of the mouth as a switch trigger, thereby allowing voluntary switch activation upon mouth opening. However, for this technology to be clinically viable, it must be validated against a gold standard switch, such as a chin switch, that taps into the same voluntary motion. Methods In this study, we report an experiment designed to gauge the concurrent validity of the infrared thermal switch. Ten able-bodied adults participated in a series of 3 test sessions where they simultaneously used both an infrared thermal and conventional chin switch to perform multiple trials of a number identification task with visual, auditory and audiovisual stimuli. Participants also provided qualitative feedback about switch use. User performance with the two switches was quantified using an efficiency measure based on mutual information. Results User performance (p = 0.16 and response time (p = 0.25 with the infrared thermal switch were comparable to those of the gold standard. Users reported preference for the infrared thermal switch given its non-contact nature and robustness to changes in user posture. Conclusions Thermal infrared access technology appears to be a valid single switch alternative for individuals with disabilities who retain voluntary mouth opening and closing.

  7. Switch-On Effectiveness Trial: Evaluation Report and Executive Summary

    Science.gov (United States)

    Patel, Rakhee; Jabin, Nico; Bussard, Loraine; Cartagena, Javiera; Haywood, Sarah; Lumpkin, Michael

    2017-01-01

    Switch-on is an intensive, targeted literacy intervention that aims to improve the reading skills of pupils who are struggling with literacy. There are two versions of the intervention: Switch-on Reading and Switch-on Reading and Writing. Both involve specially trained Teaching Assistants (TAs) delivering a tailored programme of literacy support…

  8. Aschroft Pressure Switch - Monitor for Low SCHe Supply Bottle Pressure

    International Nuclear Information System (INIS)

    VAN KATWIJK, C.

    2000-01-01

    These pressure switches are located in the SCHe helium supply lines at the pressure bottles and upstream of the PRV. The switches monitor the SCHe supply bottle pressure and are set to alarm at 2200 psig. There is one switch for each SCHe supply (4). Electronic output signal is NON-SAFETY (GS)

  9. A Switch Architecture For Real-time Multimedia Communications

    NARCIS (Netherlands)

    Smit, Gerardus Johannes Maria; Havinga, Paul J.M.

    1994-01-01

    In this paper we present a switch that can be used to transfer multimedia type of trafJic. The switch provides a guaranteed throughput and a bounded latency. We focus on the design of a prototype Switching Element using the new technology opportunities being offered today. The architecture meets the

  10. Challenges in Switching SiC MOSFET without Ringing

    DEFF Research Database (Denmark)

    Li, Helong; Munk-Nielsen, Stig

    2014-01-01

    Switching SiC MOSFET without ringing in high frequency applications is important for meeting the EMI (ElectroMagnetic Interference) standard. Achieving a clean switching waveform of SiC MOSFET without additional components is becoming a challenge. In this paper, the switching oscillation mechanism...

  11. Robust Stability Analysis of Nonlinear Switched Systems with Filippov Solutions

    DEFF Research Database (Denmark)

    Ahmadi, Mohamadreza; Mojallali, Hamed; Wisniewski, Rafal

    2012-01-01

    This paper addresses the stability problem of a class of nonlinear switched systems with partitioned state-space and state-dependent switching. In lieu of the Caratheodory solutions, the general Filippov solutions are considered. This encapsulates solutions with infinite switching in finite time....... which provides sufficient means to construct the corresponding Lyapunov functions via available semi-definite programming techniques....

  12. Packetisation in Optical Packet Switch Fabrics using adaptive timeout values

    DEFF Research Database (Denmark)

    Mortensen, Brian Bach

    2006-01-01

    Hybrid electro-optical packet switches utilize optics in the backplane to switch optical packets from inputs to outputs on electronic line cards. The optical packets are traditionally considerably larger than minimum size IP packets. IP packets entering the switch must be formatted (segmented) an...

  13. 30 CFR 75.520 - Electric equipment; switches.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electric equipment; switches. 75.520 Section 75... HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Electrical Equipment-General § 75.520 Electric equipment; switches. All electric equipment shall be provided with switches or other controls that are...

  14. RF-MEMS capacitive switches with high reliability

    Science.gov (United States)

    Goldsmith, Charles L.; Auciello, Orlando H.; Carlisle, John A.; Sampath, Suresh; Sumant, Anirudha V.; Carpick, Robert W.; Hwang, James; Mancini, Derrick C.; Gudeman, Chris

    2013-09-03

    A reliable long life RF-MEMS capacitive switch is provided with a dielectric layer comprising a "fast discharge diamond dielectric layer" and enabling rapid switch recovery, dielectric layer charging and discharging that is efficient and effective to enable RF-MEMS switch operation to greater than or equal to 100 billion cycles.

  15. A multipurpose switched reluctance motor with a series commutation buffer

    Directory of Open Access Journals (Sweden)

    L.A. Vasil'ev

    2014-06-01

    Full Text Available In this paper, a power-supply circuit for a multipurpose switched reluctance motor with a series commutation buffer is presented. It is shown that a series buffer improves output characteristics of multipurpose switched reluctance motors under supply from a single-phase circuit and also lifts necessity of switching capacitors according to the motor power supply modes.

  16. Prolactin Levels After Switching to Paliperidone Palmitate in Patients with Schizophrenia.

    Science.gov (United States)

    Nakamura, Masaru; Nagamine, Takahiko; Sato, Goro; Besho, Kazue

    2016-01-01

    Objective: The aim of this study was to investigate the tolerability and efficacy of paliperidone palmitate and its effect on the levels of prolactin in patients with schizophrenia. Method: A prospective study was carried out in 22 Japanese middle-aged patients with schizophrenia who were switched from paliperidone-extended release or risperidone long-acting injectable to paliperidone palmitate for a minimum of 12 months. Psychotic symptoms using the 18-item Brief Psychiatric Rating Scale, extrapyramidal symptoms using 9-item Drug-induced Extrapyramidal Symptoms Scale, and plasma prolactin levels using fasting blood samples were assessed at Baseline, and one, three, six, and 12 months. Results: There were significant reductions in prolactin levels at one, three, and six months relative to baseline in the male subjects switched from risperidone long-acting injectable, while prolactin levels in male subjects switched from paliperidone-extended release and the female subjects switched from risperidone long-acting injectable or paliperidone-extended release were largely unchanged. No time-sequential changes were observed in total scores of Brief Psychiatric Rating Scale and Drug-induced Extrapyramidal Symptoms Scale, irrespective of previous antipsychotics treatment. Conclusion: Switching from paliperidone-extended release or risperidone long-acting injectable to paliperidone palmitate did not result in any observed time-sequential changes in psychotic symptoms in study subjects, and prolactin levels decreased in male subjects switched from risperidone long-acting injectable. As measurement of paliperidone concentrations is limited in routine practice, a fluctuation range of prolactin levels may be a useful marker for confirmation of safety maintenance treatment with long-acting injectables in clinical settings.

  17. Superconducting Complementary Output Switching Logic Operating at 10 - 18 GHz

    Science.gov (United States)

    Jeffery, Mark; van Duzer, T.; Perold, Willem

    1998-03-01

    We have developed a new type of superconducting voltage-state logic called Complementary Output Switching Logic (COSL)(M. Jeffery, W. Perold, and T. Van Duzer, Appl. Phys. Lett., 69) (18), 2746 (1996). The basic COSL gates have been demonstrated at 10 GHz and complex 2-bit encoder circuits have operated at 5 - 8 GHz. The COSL gates have extremely low power dissipation, of order 10 μW/gate, and we have measured bit error rates less than 10-12 at 2 GHz. For these results we used the HYPRES 1 kA/cm^2 critical current density Nb Josephson fabrication process. In the present work we describe our recent test results using the new HYPRES 2.5 kA/cm^2 process. The increased critical current density process significantly improves the switching speed of the COSL devices. We will describe the Monte Carlo method used to optimize the COSL gates for 20 - 30 GHz operation, and the optimal circuit layouts including moats, or ground plane holes, to shield the circuits from trapped magnetic flux. Experimental test results will be presented for the basic COSL devices operating at 10 - 18 GHz. These are the fastest superconducting voltage-state logic devices ever reported, and may have many applications in low power ultra-high-speed digital systems of the future.

  18. Frequent interchromosomal template switches during gene conversion in S. cerevisiae

    Science.gov (United States)

    Tsaponina, Olga; Haber, James E.

    2014-01-01

    Summary Although repair of double-strand breaks (DSBs) by gene conversion is the most accurate way to repair such lesions, in budding yeast there is a thousand-fold increase in accompanying mutations, including interchromosomal template switches (ICTS) involving highly mismatched (homeologous) ectopic sequences. Although such events are rare and appear at a rate of 2×10−7 when template jumps occur between 71% identical sequences, they are surprisingly frequent (0.3% of all repair events) when the second template is identical to the first, revealing the remarkable instability of repair DNA synthesis. With homeologous donors, ICTS uses microhomologies as small as 2 bp. Cells lacking mismatch repair proteins Msh6 and Mlh1 form chimeric recombinants with two distinct patches of microhomology, implying that these proteins are crucial for strand discrimination of heteroduplex DNA formed during ICTS. We identify the chromatin remodeler Rdh54 as the first protein required for template switching that does not affect simple gene conversion. PMID:25066232

  19. Adaptive Morse-coded single-switch communication system for the disabled.

    Science.gov (United States)

    Luo, C H; Shih, C H

    1996-04-01

    Automatic recognition of Morse-code is generally developed at a fixed typing rate. However, this is not suitable for the disabled due to their difficulty in maintaining a stable typing rate. In this paper, a system recognizing varying typing speeds is developed using an adaptive technique, the Least-Mean Square (LMS) algorithm. This system helps the disabled have a wide latitude and varying typing speeds in single-switch communication with the Morse-code.

  20. Cavity length dependence of mode beating in passively Q-switched Nd-solid state lasers

    Science.gov (United States)

    Zameroski, Nathan D.; Wanke, Michael; Bossert, David

    2013-03-01

    The temporal intensity profile of pulse(s) from passively Q-switched and passively Q-switched mode locked (QSML) solid-state lasers is known to be dependent on cavity length. In this work, the pulse width, modulation depth, and beat frequencies of a Nd:Cr:GSGG laser using a Cr+4:YAG passive Q-switch are investigated as function cavity length. Measured temporal widths are linearly correlated with cavity length but generally 3-5 ns larger than theoretical predictions. Some cavity lengths exhibit pulse profiles with no modulation while other lengths exhibit complete amplitude modulation. The observed beat frequencies at certain cavity lengths cannot be accounted for with passively QSML models in which the pulse train repetition rate is τRT-1, τRT= round-trip time. They can be explained, however, by including coupled cavity mode-locking effects. A theoretical model developed for a two section coupled cavity semiconductor laser is adapted to a solid-state laser to interpret measured beat frequencies. We also numerically evaluate the temporal criterion required to achieve temporally smooth Q-switched pulses, versus cavity length and pump rate. We show that in flash lamp pumped systems, the difference in buildup time between longitudinal modes is largely dependent on the pump rate. In applications where short pulse delay is important, the pumping rate may limit the ability to achieve temporally smooth pulses in passively Q-switched lasers. Simulations support trends in experimental data. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  1. Assessment of efficacy and impact on work productivity and attendance after a mandatory switch to generic second-generation antihistamines: results of a patient survey in Norway

    Directory of Open Access Journals (Sweden)

    Ødegård Tone

    2011-02-01

    Full Text Available Abstract Background In 2006, the Norwegian Medicines Agency mandated a switch from desloratadine, ebastine, or fexofenadine to cetirizine or loratadine in patients with allergic rhinitis (AR or chronic urticaria (CU. In an online survey, patients whose medication was switched assessed the impact on efficacy, fatigue, and work productivity/attendance. Methods Allergy patients in Norway completed a 25-item online survey. Patients aged ≥ 18 years with AR or CU who were switched to cetirizine or loratadine from desloratadine, ebastine, or fexofenadine were included. Participants rated post-switch efficacy, fatigue, and effect on work productivity/attendance compared with their pre-switch medication. Patients also reported post-switch change in number of doctor visits required, total treatment cost, and whether they had switched or wanted to switch back to their previous medications. Results Of 1920 patients invited, 493 responded and 409 of these were eligible. Previous antihistamines were desloratadine (78.4% of respondents, ebastine (16.0%, and fexofenadine (5.6%. Post-switch, 64.7% received cetirizine and 35.3% loratadine. Compared with previous therapy, cetirizine and loratadine were rated less effective by 46.3% of respondents; 28.7% reported increased fatigue; and 31.6% reported decreased work productivity with the generic agents. At the time of the survey, 26% of respondents had switched back to their previous medication. Conclusions This is the first survey to assess the impact on patient-reported outcomes of a mandated switch from prescription to generic antihistamines in Norway. The findings suggest that patient response to different antihistamines will vary and that treatment decisions should be individualized for optimal results.

  2. A packet switched communications system for GRO

    Science.gov (United States)

    Husain, Shabu; Yang, Wen-Hsing; Vadlamudi, Rani; Valenti, Joseph

    1993-11-01

    This paper describes the packet switched Instrumenters Communication System (ICS) that was developed for the Command Management Facility at GSFC to support the Gamma Ray Observatory (GRO) spacecraft. The GRO ICS serves as a vital science data acquisition link to the GRO scientists to initiate commands for their spacecraft instruments. The system is ready to send and receive messages at any time, 24 hours a day and seven days a week. The system is based on X.25 and the International Standard Organization's (ISO) 7-layer Open Systems Interconnection (OSI) protocol model and has client and server components. The components of the GRO ICS are discussed along with how the Communications Subsystem for Interconnection (CSFI) and Network Control Program Packet Switching Interface (NPSI) software are used in the system.

  3. Hysteresis controller with constant switching frequency

    DEFF Research Database (Denmark)

    Poulsen, Søren; Andersen, Michael Andreas E.

    2005-01-01

    Switch mode audio power amplifiers are showing up on market in still greater numbers because of advantages in form of high efficiency and low total system cost, especially for high power amplifiers. Several different modulator topologies have been made, ranging from standard PWM to various self......-oscillating and digital modulators. Performance in terms of low distortion, noise and dynamic range differs significantly with the modulator topology used. Highest system performance is generally achieved with analog modulators made as a modulator loop including at least the power stage of the amplifier, because...... of benefits from continuous time operation and non-quantized resolution. This type of modulator uses no external carrier signal, and is called self-oscillating modulators. The work presented in this paper refers to switch mode audio power amplifier, but can be used within a wide range of DC-DC or DC...

  4. Dielectric breakdown of fast switching LCD shutters

    Science.gov (United States)

    Mozolevskis, Gatis; Sekacis, Ilmars; Nitiss, Edgars; Medvids, Arturs; Rutkis, Martins

    2017-02-01

    Fast liquid crystal optical shutters due to fast switching, vibrationless control and optical properties have found various applications: substitutes for mechanical shutters, 3D active shutter glasses, 3D volumetric displays and more. Switching speed depends not only on properties of liquid crystal, but also on applied electric field intensity. Applied field in the shutters can exceed >10 V/micron which may lead to dielectric breakdown. Therefore, a dielectric thin film is needed between transparent conductive electrodes in order to reduce breakdown probability. In this work we have compared electrical and optical properties of liquid crystal displays with dielectric thin films with thicknesses up to few hundred nanometers coated by flexo printing method and magnetron sputtering. Dielectric breakdown values show flexographic thin films to have higher resistance to dielectric breakdown, although sputtered coatings have better optical properties, such as higher transmission and no coloration.

  5. Pervasive benefits of preparation in language switching.

    Science.gov (United States)

    Fink, Angela; Goldrick, Matthew

    2015-06-01

    Many theories of bilingual language production assume that when bilinguals process words in their first language, representations from their second language are coactivated. Verhoef, Roelofs, and Chwilla (2009) proposed an alternative account, assuming that the activation of second language representations is highly limited during first language production. Using a cued language-switching task, Verhoef et al. showed that allowing participants to prepare their responses failed to facilitate first language production in some contexts. Verhoef et al. argued that this reflected a lack of coactivation of second language representations in these contexts. We report two experiments with different bilingual populations that failed to confirm the predictions of this account: Preparation consistently facilitated first language production in all contexts. This suggests that in the cued switch paradigm, both first language and second language representations are consistently activated during first language production.

  6. CQ Switch Analysis under Traffic Overload

    Directory of Open Access Journals (Sweden)

    I. Maljević

    2011-06-01

    Full Text Available An analysis of 2x2 crossbar packet switch with buffers at crosspoints and round robin scheduling algorithm is presented in this paper. The analysis is performed for a non-admissible traffic pattern, where output ports are overloaded. The case of full offered load is observed and output ports are loaded with packets that have different arrival probabilities. In addition to the parameters that are commonly observed in such an analysis (throughput and average packet delay, memory requirements for the implementation of the buffer, as well as fair representation when servicing the buffer - the so-called fairness are also analyzed. The results show that even for a switch with a small number of ports very large buffers should be implemented, if we want to achieve satisfactory performance under traffic overload.

  7. Analysis of Soft Switched Electronic Ballast

    Directory of Open Access Journals (Sweden)

    Pavol Spanik

    2003-01-01

    Full Text Available One of most perspective light sources are based on principle of electric discharge in gases. Feature of this phenomena is nonlinear impedance characteristic. Ballast interconnected between line and light source adapts requirements of light source to possibilities/requirements of the line. Today solution of modern ballast is based is based upon high frequency switch mode power supply, the cuts many disadvantages of standartd magnetic ballast off. The article describes development of high frequency electronic ballast for linear fluorescent tube in the frame of grant project 1/9025/02 with accent to soft switching. The most important advantages of this solutions are compactness, flicker-free lumen effeciency increase and reduced EMI interferencies.

  8. A Lossless Switch for Data Acquisition Networks

    CERN Document Server

    Jereczek, Grzegorz Edmund; for the ATLAS collaboration

    2015-01-01

    The recent trends in software-defined networking (SDN) and network function virtualization (NFV) are boosting the advance of software-based packet processing and forwarding on commodity servers. Although performance has traditionally been the challenge of this approach, this situation changes with modern server platforms. High performance load balancers, proxies, virtual switches and other network functions can be now implemented in software and not limited to specialized commercial hardware, thus reducing cost and increasing the flexibility. In this paper we design a lossless software-based switch for high bandwidth data acquisition (DAQ) networks, using the ATLAS experiment at CERN as a case study. We prove that it can effectively solve the incast pathology arising from the many-to-one communication pattern present in DAQ networks by providing extremely high buffering capabilities. We evaluate this on a commodity server equipped with twelve 10 Gbps Ethernet interfaces providing a total bandwidth of 120 Gbps...

  9. Design of optical switches by illusion optics

    International Nuclear Information System (INIS)

    Shoorian, H R; Abrishamian, M S

    2013-01-01

    In this paper, illusion optics theory is employed to form Bragg gratings in an optical waveguide in order to design an optical switch. By using an illusion device at a certain distance from the waveguide, the effective refractive index of the waveguide is remotely modulated, turning the waveguide into a distributed Bragg reflector (DBR) which blocks the waves at a stop band. By removing the illusion device, the waves propagate through the waveguide again. In addition, this method is used to remotely tune DBR optical properties such as resonant frequency and bandwidth in a wide range, which leads to a tunable filter for optical switching applications. Finally, using an illusion device at a distance, an optical cavity is created by inserting defects remotely in a DBR without any physical damage in the primary device. (paper)

  10. Design of optical switches by illusion optics

    Science.gov (United States)

    Shoorian, H. R.; Abrishamian, M. S.

    2013-05-01

    In this paper, illusion optics theory is employed to form Bragg gratings in an optical waveguide in order to design an optical switch. By using an illusion device at a certain distance from the waveguide, the effective refractive index of the waveguide is remotely modulated, turning the waveguide into a distributed Bragg reflector (DBR) which blocks the waves at a stop band. By removing the illusion device, the waves propagate through the waveguide again. In addition, this method is used to remotely tune DBR optical properties such as resonant frequency and bandwidth in a wide range, which leads to a tunable filter for optical switching applications. Finally, using an illusion device at a distance, an optical cavity is created by inserting defects remotely in a DBR without any physical damage in the primary device.

  11. Thermochromic materials research for optical switching

    International Nuclear Information System (INIS)

    Lee, J.C.; Jorgenson, G.V.; Lin, R.J.

    1986-01-01

    Reactive-ion-beam-sputtering (RIBS) is used to deposit doped vanadium dioxide (V/sub 1-x/M/sub x/O/sub 2/), where M is a dopant that lowers the transition temperature (T/sub t/) from that of stoichiometric VO/sub 2/. The objective is to synthesize a material that will passively switch between a heat-transmitting-and a heat-reflecting-state at specific design temperatures in the human comfort range. The films are deposited at elevated temperature (>700K) onto glass and sapphire substrates for spectrophotometric evaluation above and below T/sub t/. Then by analyzing the deposited films via EDAX, correlations between film composition and passive solar switching performance are made. Also concepts for synthesizing suitable crystallites of such materials are described. These crystallites could act as switchable pigments for throchromic solar paint

  12. Atomic switch networks as complex adaptive systems

    Science.gov (United States)

    Scharnhorst, Kelsey S.; Carbajal, Juan P.; Aguilera, Renato C.; Sandouk, Eric J.; Aono, Masakazu; Stieg, Adam Z.; Gimzewski, James K.

    2018-03-01

    Complexity is an increasingly crucial aspect of societal, environmental and biological phenomena. Using a dense unorganized network of synthetic synapses it is shown that a complex adaptive system can be physically created on a microchip built especially for complex problems. These neuro-inspired atomic switch networks (ASNs) are a dynamic system with inherent and distributed memory, recurrent pathways, and up to a billion interacting elements. We demonstrate key parameters describing self-organized behavior such as non-linearity, power law dynamics, and multistate switching regimes. Device dynamics are then investigated using a feedback loop which provides control over current and voltage power-law behavior. Wide ranging prospective applications include understanding and eventually predicting future events that display complex emergent behavior in the critical regime.

  13. Filamentary model in resistive switching materials

    Science.gov (United States)

    Jasmin, Alladin C.

    2017-12-01

    The need for next generation computer devices is increasing as the demand for efficient data processing increases. The amount of data generated every second also increases which requires large data storage devices. Oxide-based memory devices are being studied to explore new research frontiers thanks to modern advances in nanofabrication. Various oxide materials are studied as active layers for non-volatile memory. This technology has potential application in resistive random-access-memory (ReRAM) and can be easily integrated in CMOS technologies. The long term perspective of this research field is to develop devices which mimic how the brain processes information. To realize such application, a thorough understanding of the charge transport and switching mechanism is important. A new perspective in the multistate resistive switching based on current-induced filament dynamics will be discussed. A simple equivalent circuit of the device gives quantitative information about the nature of the conducting filament at different resistance states.

  14. Float level switch for a nuclear power plant containment vessel

    Science.gov (United States)

    Powell, J.G.

    1993-11-16

    This invention is a float level switch used to sense rise or drop in water level in a containment vessel of a nuclear power plant during a loss of coolant accident. The essential components of the device are a guide tube, a reed switch inside the guide tube, a float containing a magnetic portion that activates a reed switch, and metal-sheathed, ceramic-insulated conductors connecting the reed switch to a monitoring system outside the containment vessel. Special materials and special sealing techniques prevent failure of components and allow the float level switch to be connected to a monitoring system outside the containment vessel. 1 figures.

  15. New stability and stabilization for switched neutral control systems

    International Nuclear Information System (INIS)

    Xiong Lianglin; Zhong Shouming; Ye Mao; Wu Shiliang

    2009-01-01

    This paper concerns stability and stabilization issues for switched neutral systems and presents new classes of piecewise Lyapunov functionals and multiple Lyapunov functionals, based on which, two new switching rules are introduced to stabilize the neutral systems. One switching rule is designed from the solution of the so-called Lyapunov-Metzler linear matrix inequalities. The other is based on the determination of average dwell time computed from a new class of linear matrix inequalities (LMIs). And then, state-feedback control is derived for the switched neutral control system mainly based on the state switching rules. Finally, three examples are given to demonstrate the effectiveness of the proposed method.

  16. Switching terahertz wave with grating-coupled Kretschmann configuration.

    Science.gov (United States)

    Jiu-Sheng, Li

    2017-08-07

    We present a terahertz wave switch utilizing Kretschmann configuration which consists of high-refractive-index prism-liquid crystal-periodically grooved metal grating. The switching mechanism of the terahertz switch is based on spoof surface plasmon polariton (SSPP) excitation in the attenuated total reflection regime by changing the liquid crystal refractive index. The results highlighted the fact that the feasibility to "tune" the attenuated total reflection terahertz wave intensity by using the external applied bias voltage. The extinction ratio of the terahertz switch reaches 31.48dB. The terahertz switch has good control ability and flexibility, and can be used in potential terahertz free space device systems.

  17. Multiple genetic switches spontaneously modulating bacterial mutability

    Directory of Open Access Journals (Sweden)

    Johnston Randal N

    2010-09-01

    Full Text Available Abstract Background All life forms need both high genetic stability to survive as species and a degree of mutability to evolve for adaptation, but little is known about how the organisms balance the two seemingly conflicting aspects of life: genetic stability and mutability. The DNA mismatch repair (MMR system is essential for maintaining genetic stability and defects in MMR lead to high mutability. Evolution is driven by genetic novelty, such as point mutation and lateral gene transfer, both of which require genetic mutability. However, normally a functional MMR system would strongly inhibit such genomic changes. Our previous work indicated that MMR gene allele conversion between functional and non-functional states through copy number changes of small tandem repeats could occur spontaneously via slipped-strand mis-pairing during DNA replication and therefore may play a role of genetic switches to modulate the bacterial mutability at the population level. The open question was: when the conversion from functional to defective MMR is prohibited, will bacteria still be able to evolve by accepting laterally transferred DNA or accumulating mutations? Results To prohibit allele conversion, we "locked" the MMR genes through nucleotide replacements. We then scored changes in bacterial mutability and found that Salmonella strains with MMR locked at the functional state had significantly decreased mutability. To determine the generalizability of this kind of mutability 'switching' among a wider range of bacteria, we examined the distribution of tandem repeats within MMR genes in over 100 bacterial species and found that multiple genetic switches might exist in these bacteria and may spontaneously modulate bacterial mutability during evolution. Conclusions MMR allele conversion through repeats-mediated slipped-strand mis-pairing may function as a spontaneous mechanism to switch between high genetic stability and mutability during bacterial evolution.

  18. Switching power converters medium and high power

    CERN Document Server

    Neacsu, Dorin O

    2013-01-01

    An examination of all of the multidisciplinary aspects of medium- and high-power converter systems, including basic power electronics, digital control and hardware, sensors, analog preprocessing of signals, protection devices and fault management, and pulse-width-modulation (PWM) algorithms, Switching Power Converters: Medium and High Power, Second Edition discusses the actual use of industrial technology and its related subassemblies and components, covering facets of implementation otherwise overlooked by theoretical textbooks. The updated Second Edition contains many new figures, as well as

  19. Switched Systems With Multiple Invariant Sets

    Science.gov (United States)

    2015-05-06

    larger superset. We show the effectiveness of the dwell-time conditions by using examples of switching limit cycles commonly found in robotic locomotion ...commonly found in robotic locomotion and apping ight. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as Report...1 −1 1 −1 ]( x y ) + ( 2 −2 ) . This is a simplified version of (1), a central pattern generator used for control of swimming [12] or flying robots [2

  20. Switching non-local vector median filter

    Science.gov (United States)

    Matsuoka, Jyohei; Koga, Takanori; Suetake, Noriaki; Uchino, Eiji

    2016-04-01

    This paper describes a novel image filtering method that removes random-valued impulse noise superimposed on a natural color image. In impulse noise removal, it is essential to employ a switching-type filtering method, as used in the well-known switching median filter, to preserve the detail of an original image with good quality. In color image filtering, it is generally preferable to deal with the red (R), green (G), and blue (B) components of each pixel of a color image as elements of a vectorized signal, as in the well-known vector median filter, rather than as component-wise signals to prevent a color shift after filtering. By taking these fundamentals into consideration, we propose a switching-type vector median filter with non-local processing that mainly consists of a noise detector and a noise removal filter. Concretely, we propose a noise detector that proactively detects noise-corrupted pixels by focusing attention on the isolation tendencies of pixels of interest not in an input image but in difference images between RGB components. Furthermore, as the noise removal filter, we propose an extended version of the non-local median filter, we proposed previously for grayscale image processing, named the non-local vector median filter, which is designed for color image processing. The proposed method realizes a superior balance between the preservation of detail and impulse noise removal by proactive noise detection and non-local switching vector median filtering, respectively. The effectiveness and validity of the proposed method are verified in a series of experiments using natural color images.