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Sample records for instantaneous reactive power

  1. New Approach to Optimize the Apfs Placement Based on Instantaneous Reactive Power Theory by Genetic Algorithm

    NASA Astrophysics Data System (ADS)

    Hashemi-Dezaki, Hamed; Mohammadalizadeh-Shabestary, Masoud; Askarian-Abyaneh, Hossein; Rezaei-Jegarluei, Mohammad

    2014-01-01

    In electrical distribution systems, a great amount of power are wasting across the lines, also nowadays power factors, voltage profiles and total harmonic distortions (THDs) of most loads are not as would be desired. So these important parameters of a system play highly important role in wasting money and energy, and besides both consumers and sources are suffering from a high rate of distortions and even instabilities. Active power filters (APFs) are innovative ideas for solving of this adversity which have recently used instantaneous reactive power theory. In this paper, a novel method is proposed to optimize the allocation of APFs. The introduced method is based on the instantaneous reactive power theory in vectorial representation. By use of this representation, it is possible to asses different compensation strategies. Also, APFs proper placement in the system plays a crucial role in either reducing the losses costs and power quality improvement. To optimize the APFs placement, a new objective function has been defined on the basis of five terms: total losses, power factor, voltage profile, THD and cost. Genetic algorithm has been used to solve the optimization problem. The results of applying this method to a distribution network illustrate the method advantages.

  2. Reactive power compensator

    DOEpatents

    El-Sharkawi, Mohamed A.; Venkata, Subrahmanyam S.; Chen, Mingliang; Andexler, George; Huang, Tony

    1992-01-01

    A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation.

  3. Reactive Power Compensator.

    DOEpatents

    El-Sharkawi, M.A.; Venkata, S.S.; Chen, M.; Andexler, G.; Huang, T.

    1992-07-28

    A system and method for determining and providing reactive power compensation for an inductive load. A reactive power compensator (50,50') monitors the voltage and current flowing through each of three distribution lines (52a, 52b, 52c), which are supplying three-phase power to one or more inductive loads. Using signals indicative of the current on each of these lines when the voltage waveform on the line crosses zero, the reactive power compensator determines a reactive power compensator capacitance that must be connected to the lines to maintain a desired VAR level, power factor, or line voltage. Alternatively, an operator can manually select a specific capacitance for connection to each line, or the capacitance can be selected based on a time schedule. The reactive power compensator produces control signals, which are coupled through optical fibers (102/106) to a switch driver (110, 110') to select specific compensation capacitors (112) for connections to each line. The switch driver develops triggering signals that are supplied to a plurality of series-connected solid state switches (350), which control charge current in one direction in respect to ground for each compensation capacitor. During each cycle, current flows from ground to charge the capacitors as the voltage on the line begins to go negative from its positive peak value. The triggering signals are applied to gate the solid state switches into a conducting state when the potential on the lines and on the capacitors reaches a negative peak value, thereby minimizing both the potential difference and across the charge current through the switches when they begin to conduct. Any harmonic distortion on the potential and current carried by the lines is filtered out from the current and potential signals used by the reactive power compensator so that it does not affect the determination of the required reactive compensation. 26 figs.

  4. Reactive power compensating system

    DOEpatents

    Williams, Timothy J.; El-Sharkawi, Mohamed A.; Venkata, Subrahmanyam S.

    1987-01-01

    The reactive power of an induction machine is compensated by providing fixed capacitors on each phase line for the minimum compensation required, sensing the current on one line at the time its voltage crosses zero to determine the actual compensation required for each phase, and selecting switched capacitors on each line to provide the balance of the compensation required.

  5. Reactive Power Compensating System.

    DOEpatents

    Williams, Timothy J.; El-Sharkawi, Mohamed A.; Venkata, Subrahmanyam S.

    1985-01-04

    The circuit was designed for the specific application of wind-driven induction generators. It has great potential for application in any situation where a varying reactive power load is present, such as with induction motors or generators, or for transmission network compensation.

  6. Design of Instantaneous High Power Supply System with power distribution management for portable military devices

    NASA Astrophysics Data System (ADS)

    Kwak, Kiho; Kwak, Dongmin; Yoon, Joohong

    2015-08-01

    A design of an Instantaneous High Power Supply System (IHPSS) with a power distribution management (PDM) for portable military devices is newly addressed. The system includes a power board and a hybrid battery that can not only supply instantaneous high power but also maintain stable operation at critical low temperature (-30 °C). The power leakage and battery overcharge are effectively prevented by the optimal PDM. The performance of the proposed system under the required pulse loads and the operating conditions of a Korean Advanced Combat Rifle employed in the battlefield is modeled with simulations and verified experimentally. The system with the IHPSS charged the fuse setter with 1.7 times higher voltage (8.6 V) than the one without (5.4 V) under the pulse discharging rate (1 A at 0.5 duty, 1 ms) for 500 ms.

  7. Reactive Power from Distributed Energy

    SciTech Connect

    Kueck, John; Kirby, Brendan; Rizy, Tom; Li, Fangxing; Fall, Ndeye

    2006-12-15

    Distributed energy is an attractive option for solving reactive power and distribution system voltage problems because of its proximity to load. But the cost of retrofitting DE devices to absorb or produce reactive power needs to be reduced. There also needs to be a market mechanism in place for ISOs, RTOs, and transmission operators to procure reactive power from the customer side of the meter where DE usually resides. (author)

  8. DC uninterrupted power supply having instantaneous switching followed by low impedance switching

    NASA Astrophysics Data System (ADS)

    Hammond, Russell E.; Northup, Robert L.; Shimp, Alan G.

    1991-10-01

    An uninterruptible power supply is provided that incorporates switching circuitry permitting a path for instantaneous DC backup power to be supplied to a voltage-declining primary power supply bus. Once the instantaneous transition is made, battery power is switched to a low impedance path to provide long-term battery power delivery to the bus. At a point where the backup batteries no longer supply useful power to a load, disabling circuitry disconnects the batteries from the load so that excessive draining of the batteries does not result in irreversible battery damage. The uninterruptible power supply of the invention further includes an automatic battery charging circuitry that seeks to maintain the power supply batteries at optimal charge level. To enable an operator to adequately assess battery charge condition, the invention provides battery test circuitry that causes a simulated load to appear at the power supply batteries. Visual representations are then made as to battery status.

  9. A Tariff for Reactive Power

    SciTech Connect

    Kueck, John D; Kirby, Brendan J; Li, Fangxing; Tufon, Christopher; Isemonger, Alan

    2008-07-01

    Two kinds of power are required to operate an electric power system: real power, measured in watts, and reactive power, measured in volt-amperes reactive or VARs. Reactive power supply is one of a class of power system reliability services collectively known as ancillary services, and is essential for the reliable operation of the bulk power system. Reactive power flows when current leads or lags behind voltage. Typically, the current in a distribution system lags behind voltage because of inductive loads such as motors. Reactive power flow wastes energy and capacity and causes voltage droop. To correct lagging power flow, leading reactive power (current leading voltage) is supplied to bring the current into phase with voltage. When the current is in phase with voltage, there is a reduction in system losses, an increase in system capacity, and a rise in voltage. Reactive power can be supplied from either static or dynamic VAR sources. Static sources are typically transmission and distribution equipment, such as capacitors at substations, and their cost has historically been included in the revenue requirement of the transmission operator (TO), and recovered through cost-of-service rates. By contrast, dynamic sources are typically generators capable of producing variable levels of reactive power by automatically controlling the generator to regulate voltage. Transmission system devices such as synchronous condensers can also provide dynamic reactive power. A class of solid state devices (called flexible AC transmission system devices or FACTs) can provide dynamic reactive power. One specific device has the unfortunate name of static VAR compensator (SVC), where 'static' refers to the solid state nature of the device (it does not include rotating equipment) and not to the production of static reactive power. Dynamic sources at the distribution level, while more costly would be very useful in helping to regulate local voltage. Local voltage regulation would reduce

  10. Independent component analysis of instantaneous power-based fMRI.

    PubMed

    Zhong, Yuan; Zheng, Gang; Liu, Yijun; Lu, Guangming

    2014-01-01

    In functional magnetic resonance imaging (fMRI) studies using spatial independent component analysis (sICA) method, a model of "latent variables" is often employed, which is based on the assumption that fMRI data are linear mixtures of statistically independent signals. However, actual fMRI signals are nonlinear and do not automatically meet with the requirement of sICA. To provide a better solution to this problem, we proposed a novel approach termed instantaneous power based fMRI (ip-fMRI) for regularization of fMRI data. Given that the instantaneous power of fMRI signals is a scalar value, it should be a linear mixture that naturally satisfies the "latent variables" model. Based on our simulated data, the curves of accuracy and resulting receiver-operating characteristic curves indicate that the proposed approach is superior to the traditional fMRI in terms of accuracy and specificity by using sICA. Experimental results from human subjects have shown that spatial components of a hand movement task-induced activation reveal a brain network more specific to motor function by ip-fMRI than that by the traditional fMRI. We conclude that ICA decomposition of ip-fMRI may be used to localize energy signal changes in the brain and may have a potential to be applied to detection of brain activity.

  11. Independent Component Analysis of Instantaneous Power-Based fMRI

    PubMed Central

    Liu, Yijun; Lu, Guangming

    2014-01-01

    In functional magnetic resonance imaging (fMRI) studies using spatial independent component analysis (sICA) method, a model of “latent variables” is often employed, which is based on the assumption that fMRI data are linear mixtures of statistically independent signals. However, actual fMRI signals are nonlinear and do not automatically meet with the requirement of sICA. To provide a better solution to this problem, we proposed a novel approach termed instantaneous power based fMRI (ip-fMRI) for regularization of fMRI data. Given that the instantaneous power of fMRI signals is a scalar value, it should be a linear mixture that naturally satisfies the “latent variables” model. Based on our simulated data, the curves of accuracy and resulting receiver-operating characteristic curves indicate that the proposed approach is superior to the traditional fMRI in terms of accuracy and specificity by using sICA. Experimental results from human subjects have shown that spatial components of a hand movement task-induced activation reveal a brain network more specific to motor function by ip-fMRI than that by the traditional fMRI. We conclude that ICA decomposition of ip-fMRI may be used to localize energy signal changes in the brain and may have a potential to be applied to detection of brain activity. PMID:24738008

  12. Local control of reactive power by distributed photovoltaic generators

    SciTech Connect

    Chertkov, Michael; Turitsyn, Konstantin; Sulc, Petr; Backhaus, Scott

    2010-01-01

    High penetration levels of distributed photovoltaic (PV) generation on an electrical distribution circuit may severely degrade power quality due to voltage sags and swells caused by rapidly varying PV generation during cloud transients coupled with the slow response of existing utility compensation and regulation equipment. Although not permitted under current standards for interconnection of distributed generation, fast-reacting, VAR-capable PV inverters may provide the necessary reactive power injection or consumption to maintain voltage regulation under difficult transient conditions. As side benefit, the control of reactive power injection at each PV inverter provides an opportunity and a new tool for distribution utilities to optimize the performance of distribution circuits, e.g. by minimizing thermal losses. We suggest a local control scheme that dispatches reactive power from each PV inverter based on local instantaneous measurements of the real and reactive components of the consumed power and the real power generated by the PVs. Using one adjustable parameter per circuit, we balance the requirements on power quality and desire to minimize thermal losses. Numerical analysis of two exemplary systems, with comparable total PV generation albeit a different spatial distribution, show how to adjust the optimization parameter depending on the goal. Overall, this local scheme shows excellent performance; it's capable of guaranteeing acceptable power quality and achieving significant saving in thermal losses in various situations even when the renewable generation in excess of the circuit own load, i.e. feeding power back to the higher-level system.

  13. Electret film-enhanced triboelectric nanogenerator matrix for self-powered instantaneous tactile imaging.

    PubMed

    Yang, Ya; Zhang, Hulin; Zhong, Xiandai; Yi, Fang; Yu, Ruomeng; Zhang, Yue; Wang, Zhong Lin

    2014-03-12

    We report the first self-powered electronic skin that consists of light-emitting diode (LED) and triboelectric nanogenerator (TENG) arrays that can be utilized for spatially mapping applied instantaneous-touch events and tracking the movement location of the target object by recording the electroluminescent signals of the LEDs without external power sources. The electret film-based TENG can deliver an open-circuit voltage of about -1070 V, a short-circuit current density of 10 mA/m(2), and a power density of 288 mW/m(2) on an external load of 100 MΩ. The LEDs can be turned on locally when the back surface of the active matrix is touched, and the intensity of the emitted light depends on the magnitude of the applied local pressure on the device. A constructed active matrix of the LED-TENG array (8 × 7 pixels) can achieve self-powered, visual, and high-resolution tactile sensing by recording the electroluminescent signals from all of the pixels, where the active size of each pixel can be decreased to 10 mm(2). This work is a significant step forward in self-powered tactile-mapping visualization technology, with a wide range of potential applications in touchpad technology, personal signatures, smart wallpapers, robotics, and safety-monitoring devices.

  14. Estimating maximum instantaneous distortion from inlet total pressure rms and PSD measurements. [Root Mean Square and Power Spectral Density methods

    NASA Technical Reports Server (NTRS)

    Melick, H. C., Jr.; Ybarra, A. H.; Bencze, D. P.

    1975-01-01

    An inexpensive method is developed to determine the extreme values of instantaneous inlet distortion. This method also provides insight into the basic mechanics of unsteady inlet flow and the associated engine reaction. The analysis is based on fundamental fluid dynamics and statistical methods to provide an understanding of the turbulent inlet flow and quantitatively relate the rms level and power spectral density (PSD) function of the measured time variant total pressure fluctuations to the strength and size of the low pressure regions. The most probable extreme value of the instantaneous distortion is then synthesized from this information in conjunction with the steady state distortion. Results of the analysis show the extreme values to be dependent upon the steady state distortion, the measured turbulence rms level and PSD function, the time on point, and the engine response characteristics. Analytical projections of instantaneous distortion are presented and compared with data obtained by a conventional, highly time correlated, 40 probe instantaneous pressure measurement system.

  15. Power-balancing instantaneous optimization energy management for a novel series-parallel hybrid electric bus

    NASA Astrophysics Data System (ADS)

    Sun, Dongye; Lin, Xinyou; Qin, Datong; Deng, Tao

    2012-11-01

    Energy management(EM) is a core technique of hybrid electric bus(HEB) in order to advance fuel economy performance optimization and is unique for the corresponding configuration. There are existing algorithms of control strategy seldom take battery power management into account with international combustion engine power management. In this paper, a type of power-balancing instantaneous optimization(PBIO) energy management control strategy is proposed for a novel series-parallel hybrid electric bus. According to the characteristic of the novel series-parallel architecture, the switching boundary condition between series and parallel mode as well as the control rules of the power-balancing strategy are developed. The equivalent fuel model of battery is implemented and combined with the fuel of engine to constitute the objective function which is to minimize the fuel consumption at each sampled time and to coordinate the power distribution in real-time between the engine and battery. To validate the proposed strategy effective and reasonable, a forward model is built based on Matlab/Simulink for the simulation and the dSPACE autobox is applied to act as a controller for hardware in-the-loop integrated with bench test. Both the results of simulation and hardware-in-the-loop demonstrate that the proposed strategy not only enable to sustain the battery SOC within its operational range and keep the engine operation point locating the peak efficiency region, but also the fuel economy of series-parallel hybrid electric bus(SPHEB) dramatically advanced up to 30.73% via comparing with the prototype bus and a similar improvement for PBIO strategy relative to rule-based strategy, the reduction of fuel consumption is up to 12.38%. The proposed research ensures the algorithm of PBIO is real-time applicability, improves the efficiency of SPHEB system, as well as suite to complicated configuration perfectly.

  16. Instantaneous Impulses.

    ERIC Educational Resources Information Center

    Erlichson, Herman

    2000-01-01

    Describes an experiment that extends Newton's instantaneous-impulse method of orbital analysis to a graphical method of orbit determination. Discusses the experiment's usefulness for teaching both horizontal projectile motion and instantaneous impulse. (WRM)

  17. Instantaneous quantification of skeletal muscle activation, power production, and fatigue during cycle ergometry.

    PubMed

    Coelho, A C; Cannon, D T; Cao, R; Porszasz, J; Casaburi, R; Knorst, M M; Rossiter, H B

    2015-03-01

    A rapid switch from hyperbolic to isokinetic cycling allows the velocity-specific decline in maximal power to be measured, i.e., fatigue. We reasoned that, should the baseline relationship between isokinetic power (Piso) and electromyography (EMG) be reproducible, then contributions to fatigue may be isolated from 1) the decline in muscle activation (muscle activation fatigue); and 2) the decline in Piso at a given activation (muscle fatigue). We hypothesized that the EMG-Piso relationship is linear, velocity dependent, and reliable for instantaneous fatigue assessment at intolerance during and following whole body exercise. Healthy participants (n = 13) completed short (5 s) variable-effort isokinetic bouts at 50, 70, and 100 rpm to characterize baseline EMG-Piso. Repeated ramp incremental exercise tests were terminated with maximal isokinetic cycling (5 s) at 70 rpm. Individual baseline EMG-Piso relationships were linear (r(2) = 0.95 ± 0.04) and velocity dependent (analysis of covariance). Piso at intolerance (two legs, 335 ± 88 W) was ∼45% less than baseline [630 ± 156 W, confidence interval of the difference (CIDifference) 211, 380 W, P < 0.05]. Following intolerance, Piso recovered rapidly (F = 44.1; P < 0.05; η(2) = 0.79): power was reduced (P < 0.05) vs. baseline only at 0-min (CIDifference 80, 201 W) and 1-min recovery (CIDifference 13, 80 W). Activation fatigue and muscle fatigue (one leg) were 97 ± 55 and 60 ± 50 W, respectively. Mean bias ± limits of agreement for reproducibility were as follows: baseline Piso 1 ± 30 W; Piso at 0-min recovery 3 ± 35 W; and EMG at Piso 3 ± 14%. EMG power is linear, velocity dependent, and reproducible. Deviation from this relationship at the limit of tolerance can quantify the "activation" and "muscle" related components of fatigue during cycling.

  18. Effects of temperature on the maximal instantaneous muscle power of humans.

    PubMed

    Ferretti, G; Ishii, M; Moia, C; Cerretelli, P

    1992-01-01

    The maximal instantaneous muscle power (wi,max) probably reflects the maximal rate of adenosine 5'-triphosphate (ATP) hydrolysis (ATPmax), a temperature-dependent variable, which gives rise to the hypothesis that temperature, by affecting ATPmax, may also influence wi,max. This hypothesis was tested on six subjects, whose vastus lateralis muscle temperature (Tmuscle) was monitored by a thermocouple inserted approximately 3 cm below the skin surface. The Wi,max was determined during a series of high jumps off both feet on a force platform before and after immersion up to the abdomen for 90 min in a temperature controlled (T = 20 +/- 0.1 degrees C) water bath. Control Tmuscle was 35.8 +/- 0.7 degrees C, with control Wi,max being 51.6 (SD 8.7) W.kg-1. After cold exposure, Tmuscle decreased by about 8 degrees C, whereas wi,max 27% lower. The temperature dependence of Wi,max was found to be less (Q10 less than 1.5, where Q10 is the temperature coefficient as calculated in other studies) than reported in the literature for ATPmax. Such a low Q10 may reflect an increase in the mechanical equivalent of ATP splitting, as a consequence of the reduced velocity of muscle contraction occurring at low Tmuscle.

  19. Optimal reactive power control of grid connected photovoltaic resources

    NASA Astrophysics Data System (ADS)

    Trimble, Joshua Ryan

    As more photovoltaic distributed generation resources are installed on distribution power systems, selective control of the inverters connecting the DC power sources presents the opportunity to supply both real and reactive power at the point of common coupling. This thesis presents a simulated distribution system with individually controlled PV resources with the objective of minimizing total system losses while operating at the maximum power point and below the simulated rating of the associated inverters. The control strategy assumes the characteristics of the distribution system are known and solves for the optimal power flow operating point. The ability of each PV source to provide real and reactive power varies instantaneously as irradiance changes, so the operating point for each resource must be constantly recalculated and adjusted. The assumption of known system paramaters can be justified in a SmartGrid context, and a solution based on overall system power flow should be considered as a benchmark for any other state estimation or local control approaches.

  20. Water reactive hydrogen fuel cell power system

    SciTech Connect

    Wallace, Andrew P; Melack, John M; Lefenfeld, Michael

    2014-11-25

    A water reactive hydrogen fueled power system includes devices and methods to combine reactant fuel materials and aqueous solutions to generate hydrogen. The generated hydrogen is converted in a fuel cell to provide electricity. The water reactive hydrogen fueled power system includes a fuel cell, a water feed tray, and a fuel cartridge to generate power for portable power electronics. The removable fuel cartridge is encompassed by the water feed tray and fuel cell. The water feed tray is refillable with water by a user. The water is then transferred from the water feed tray into the fuel cartridge to generate hydrogen for the fuel cell which then produces power for the user.

  1. Water reactive hydrogen fuel cell power system

    SciTech Connect

    Wallace, Andrew P; Melack, John M; Lefenfeld, Michael

    2014-01-21

    A water reactive hydrogen fueled power system includes devices and methods to combine reactant fuel materials and aqueous solutions to generate hydrogen. The generated hydrogen is converted in a fuel cell to provide electricity. The water reactive hydrogen fueled power system includes a fuel cell, a water feed tray, and a fuel cartridge to generate power for portable power electronics. The removable fuel cartridge is encompassed by the water feed tray and fuel cell. The water feed tray is refillable with water by a user. The water is then transferred from the water feed tray into a fuel cartridge to generate hydrogen for the fuel cell which then produces power for the user.

  2. Compensation for Harmonic Currents and Reactive Power in Wind Power Generation System using PWM Inverter

    NASA Astrophysics Data System (ADS)

    Shinohara, Katsuji; Shinhatsubo, Kurato; Iimori, Kenichi; Yamamoto, Kichiro; Saruban, Takamichi; Yamaemori, Takahiro

    In recent year, consciousness of environmental problems is enhancing, and the price of the electric power purchased by an electric power company is established expensive for the power plant utilizing the natural energy. So, the introduction of the wind power generation is promoted in Japan. Generally, squirrel-cage induction machines are widely used as a generator in wind power generation system because of its small size, lightweight and low-cost. However, the induction machines do not have a source of excitation. Thus, it causes the inrush currents and the instantaneous voltage drop when the generator is directly connected to a power grid. To reduce the inrush currents, an AC power regulator is used. Wind power generations are frequently connected to and disconnected from the power grid. However, when the inrush currents are reduced, harmonic currents are caused by phase control of the AC power regulator. And the phase control of AC power regulator cannot control the power factor. Therefore, we propose the use of the AC power regulator to compensate for the harmonic currents and reactive power in the wind power generation system, and demonstrate the validity of its system by simulated and experimental results.

  3. On reactive high power impulse magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Gudmundsson, J. T.

    2016-01-01

    High power impulse magnetron sputtering (HiPIMS) is an ionized physical vapor deposition (IPVD) technique that is particularly promising for reactive sputtering applications. However, there are few issues that have to be resolved before the full potential of this technique can be realized. Here we give an overview of the key experimental findings for the reactive HiPIMS discharge. An increase in the discharge current is commonly observed with increased partial pressure of the reactive gas or decreased repetition pulse frequency. There are somewhat conflicting claims regarding the hysteresis effect in the reactive HiPIMS discharge as some report reduction or elimination of the hysteresis effect while others claim a feedback control is essential. The ion energy distribution of the metal ion and the atomic ion of the reactive gas are similar and extend to very high energies while the ion energy distribution of the working gas and the molecular ion of the reactive gas are similar and are much less energetic.

  4. Instantaneous Power Control of PWM Rectifier Using Hysteresis Regulator with Frequency Characteristic

    NASA Astrophysics Data System (ADS)

    Noguchi, Toshihiko; Sano, Kohji

    This paper proposes a hysteresis regulator with a frequency characteristic, which reduces specific harmonic power in a direct power control system of a current-source PWM rectifier. The method virtually adjusts the hysteresis bandwidth in association with frequencies of the power pulsation; hence the regulator is capable to filter specific frequency components of the input current as well as the power. The paper describes a theoretical aspect of the proposed approach, and presents some experimental results of a particular case, where the 5th and the 7th harmonic input currents are mainly suppressed by eliminating the 6th harmonic component of the active power.

  5. Determinants of maximal instantaneous muscle power in women aged 50-75 years.

    PubMed

    De Vito, G; Bernardi, M; Forte, R; Pulejo, C; Macaluso, A; Figura, F

    1998-06-01

    The present study aimed at analysing the age-related decline in maximal muscle power (W) in 52 sedentary healthy women aged between 50 and 75 years to determine whether force or velocity is the major determinant. Maximal muscle power was estimated from two types of vertical jumps, squatting (SJ) and countermovement (CmJ), performed on a force platform. It was obtained by measuring the vertical force (F(opt)) applied to the body centre of gravity and calculating the corresponding vertical velocity (v(opt)). An age-related decline in absolute W was statistically significant in all the conditions examined and in both peak W and average power (W) values. The decrease in v(opt) was also statistically significant. Also F(opt) declined but this reduction was not statistically significant with the exception of the average value in CmJ. Not surprisingly the highest W were obtained in CmJ, and the difference in power production between the two types of jump showed an age-related decrement only in W. The main finding of the study was the demonstration that v(opt) was the critical determinant of the age-related decline in W in healthy elderly women.

  6. New hybrid active power filter for harmonic current suppression and reactive power compensation

    NASA Astrophysics Data System (ADS)

    Biricik, Samet; Cemal Ozerdem, Ozgur; Redif, Soydan; Sezai Dincer, Mustafa

    2016-08-01

    In the case of undistorted and balanced grid voltages, low ratio shunt active power filters (APFs) can give unity power factors and achieve current harmonic cancellation. However, this is not possible when source voltages are distorted and unbalanced. In this study, the cost-effective hybrid active power filter (HAPF) topology for satisfying the requirements of harmonic current suppression and non-active power compensation for industry is presented. An effective strategy is developed to observe the effect of the placement of power capacitors and LC filters with the shunt APF. A new method for alleviating the negative effects of a nonideal grid voltage is proposed that uses a self-tuning filter algorithm with instantaneous reactive power theory. The real-time control of the studied system was achieved with a field-programmable gate array (FPGA) architecture, which was developed using the OPAL-RT system. The performance result of the proposed HAPF system is tested and presented under nonideal supply voltage conditions.

  7. 77 FR 24949 - Reactive Power Resources; Supplemental Notice Requesting Comments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-26

    ... Energy Regulatory Commission Reactive Power Resources; Supplemental Notice Requesting Comments On April... whether the Commission should reconsider or modify the reactive power provisions of Order No. 661-A and examine what evidence could be developed under Order No. 661 to support a request to apply reactive...

  8. Control circuit maintains unity power factor of reactive load

    NASA Technical Reports Server (NTRS)

    Kramer, M.; Martinage, L. H.

    1966-01-01

    Circuit including feedback control elements automatically corrects the power factor of a reactive load. It maintains power supply efficiency where negative load reactance changes and varies by providing corrective error signals to the control windings of a power supply transformer.

  9. Voltage Stability Impact of Grid-Tied Photovoltaic Systems Utilizing Dynamic Reactive Power Control

    NASA Astrophysics Data System (ADS)

    Omole, Adedamola

    Photovoltaic (PV) DGs can be optimized to provide reactive power support to the grid, although this feature is currently rarely utilized as most DG systems are designed to operate with unity power factor and supply real power only to the grid. In this work, the voltage stability of a power system embedded with PV DG is examined in the context of the high reactive power requirement after a voltage sag or fault. A real-time dynamic multi-function power controller that enables renewable source PV DGs to provide the reactive power support necessary to maintain the voltage stability of the microgrid, and consequently, the wider power system is proposed. The loadability limit necessary to maintain the voltage stability of an interconnected microgrid is determined by using bifurcation analysis to test for the singularity of the network Jacobian and load differential equations with and without the contribution of the DG. The maximum and minimum real and reactive power support permissible from the DG is obtained from the loadability limit and used as the limiting factors in controlling the real and reactive power contribution from the PV source. The designed controller regulates the voltage output based on instantaneous power theory at the point-of-common coupling (PCC) while the reactive power supply is controlled by means of the power factor and reactive current droop method. The control method is implemented in a modified IEEE 13-bus test feeder system using PSCADRTM power system analysis software and is applied to the model of a Tampa ElectricRTM PV installation at Lowry Park Zoo in Tampa, FL. This dissertation accomplishes the systematic analysis of the voltage impact of a PV DG-embedded power distribution system. The method employed in this work bases the contribution of the PV resource on the voltage stability margins of the microgrid rather than the commonly used loss-of-load probability (LOLP) and effective load-carrying capability (ELCC) measures. The results of

  10. Distributed control of reactive power flow in a radial distribution circuit with high photovoltaic penetration

    SciTech Connect

    Chertkov, Michael; Turitsyn, Konstantin; Backhaus, Scott; Sule, Petr

    2009-01-01

    We show how distributed control of reactive power can serve to regulate voltage and minimize resistive losses in a distribution circuit that includes a significant level of photovoltaic (PV) generation. To demonstrate the technique, we consider a radial distribution circuit with a single branch consisting of sequentially-arranged residential-scale loads that consume both real and reactive power. In parallel, some loads also have PV generation capability. We postulate that the inverters associated with each PV system are also capable of limited reactive power generation or consumption, and we seek to find the optimal dispatch of each inverter's reactive power to both maintain the voltage within an acceptable range and minimize the resistive losses over the entire circuit. We assume the complex impedance of the distribution circuit links and the instantaneous load and PV generation at each load are known. We compare the results of the optimal dispatch with a suboptimal local scheme that does not require any communication. On our model distribution circuit, we illustrate the feasibility of high levels of PV penetration and a significant (20% or higher) reduction in losses.

  11. Optimized Reactive Power Compensation Using Fuzzy Logic Controller

    NASA Astrophysics Data System (ADS)

    George, S.; Mini, K. N.; Supriya, K.

    2015-03-01

    Reactive power flow in a long transmission line plays a vital role in power transfer capability and voltage stability in power system. Traditionally, shunt connected compensators are used to control reactive power in long transmission line. Thyristor controlled reactor is used to control reactive power under lightly loaded condition. By controlling firing angle of thyristor, it is possible to control reactive power in the transmission lines. However, thyristor controlled reactor will inject harmonic current into the system. An attempt to reduce reactive power injection will increase harmonic distortion in the line current and vice versa. Thus, there is a trade-off between reactive power injection and harmonics in current. By optimally controlling the reactive power injection, harmonics in current can be brought within the specified limit. In this paper, a Fuzzy Logic Controller is implemented to obtain optimal control of reactive power of the compensator to maintain voltage and harmonic in current within the limits. An algorithm which optimizes the firing angle in each fuzzy subset by calculating the rank of feasible firing angles is proposed for the construction of rules in Fuzzy Logic Controller. The novelty of the algorithm is that it uses a simple error formula for the calculation of the rank of the feasible firing angles in each fuzzy subset.

  12. 77 FR 11109 - Reactive Power Resources; Notice of Technical Conference

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-24

    ... energy storage resources; the design options for and cost of installing reactive power equipment at the... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Reactive Power Resources; Notice of Technical Conference The Federal...

  13. The multifunctional reactive power compensation controller based on SOC

    NASA Astrophysics Data System (ADS)

    Wang, Yongning; Qi, Changyuan; Wang, Decheng; Wang, Jun; Wang, PeiJun

    2006-11-01

    This paper proposes a new reactive power compensation controller based on SOC in order to control reactive power and voltage. The result of experiment showed that this project can not only effectively detect the oscillatory switching time after time of capacitors in their group boxes but also have the advantage of simple structure, high reliability and low cost, Because of the SOC integrating A/D convert unit, LCD/LED display unit and Multi-functional power measurement unit. An electric-current measure circuit is also designed in this article, which can detect capacitor group troubles. This system can also realized the assistant functions of calculating and displaying voltage, current, active power, reactive power, frequency and power factor of three phases.

  14. Instantaneous Frequency Attribute Comparison

    NASA Astrophysics Data System (ADS)

    Yedlin, M. J.; Margrave, G. F.; Ben Horin, Y.

    2013-12-01

    The instantaneous seismic data attribute provides a different means of seismic interpretation, for all types of seismic data. It first came to the fore in exploration seismology in the classic paper of Taner et al (1979), entitled " Complex seismic trace analysis". Subsequently a vast literature has been accumulated on the subject, which has been given an excellent review by Barnes (1992). In this research we will compare two different methods of computation of the instantaneous frequency. The first method is based on the original idea of Taner et al (1979) and utilizes the derivative of the instantaneous phase of the analytic signal. The second method is based on the computation of the power centroid of the time-frequency spectrum, obtained using either the Gabor Transform as computed by Margrave et al (2011) or the Stockwell Transform as described by Stockwell et al (1996). We will apply both methods to exploration seismic data and the DPRK events recorded in 2006 and 2013. In applying the classical analytic signal technique, which is known to be unstable, due to the division of the square of the envelope, we will incorporate the stabilization and smoothing method proposed in the two paper of Fomel (2007). This method employs linear inverse theory regularization coupled with the application of an appropriate data smoother. The centroid method application is straightforward and is based on the very complete theoretical analysis provided in elegant fashion by Cohen (1995). While the results of the two methods are very similar, noticeable differences are seen at the data edges. This is most likely due to the edge effects of the smoothing operator in the Fomel method, which is more computationally intensive, when an optimal search of the regularization parameter is done. An advantage of the centroid method is the intrinsic smoothing of the data, which is inherent in the sliding window application used in all Short-Time Fourier Transform methods. The Fomel technique

  15. Index-based reactive power compensation scheme for voltage regulation

    NASA Astrophysics Data System (ADS)

    Dike, Damian Obioma

    2008-10-01

    Increasing demand for electrical power arising from deregulation and the restrictions posed to the construction of new transmission lines by environment, socioeconomic, and political issues had led to higher grid loading. Consequently, voltage instability has become a major concern, and reactive power support is vital to enhance transmission grid performance. Improved reactive power support to distressed grid is possible through the application of relatively unfamiliar emerging technologies of "Flexible AC Transmission Systems (FACTS)" devices and "Distributed Energy Resources (DERS)." In addition to these infrastructure issues, a lack of situational awareness by system operators can cause major power outages as evidenced by the August 14, 2003 widespread North American blackout. This and many other recent major outages have highlighted the inadequacies of existing power system indexes. In this work, a novel "Index-based reactive compensation scheme" appropriate for both on-line and off-line computation of grid status has been developed. A new voltage stability index (Ls-index) suitable for long transmission lines was developed, simulated, and compared to the existing two-machine modeled L-index. This showed the effect of long distance power wheeling amongst regional transmission organizations. The dissertation further provided models for index modulated voltage source converters (VSC) and index-based load flow analysis of both FACTS and microgrid interconnected power systems using the Newton-Raphson's load flow model incorporated with multi-FACTS devices. The developed package has been made user-friendly through the embodiment of interactive graphical user interface and implemented on the IEEE 14, 30, and 300 bus systems. The results showed reactive compensation has system wide-effect, provided readily accessible system status indicators, ensured seamless DERs interconnection through new islanding modes and enhanced VSC utilization. These outcomes may contribute

  16. Reactive power in the full Gaussian light wave.

    PubMed

    Seshadri, S R

    2009-11-01

    The electric current sources that are required for the excitation of the fundamental Gaussian beam and the corresponding full Gaussian light wave are determined. The current sources are situated on the secondary source plane that forms the boundary between the two half-spaces in which the waves are launched. The electromagnetic fields and the complex power generated by the current sources are evaluated. For the fundamental Gaussian beam, the reactive power vanishes, and the normalization is chosen such that the real power is 2 W. The various full Gaussian waves are identified by the length parameter b(t) that lies in the range 0 < or = b(t) < or = b, where b is the Rayleigh distance. The other parameters are the wavenumber k, the free-space wavelength lambda, and the beam waist w0 at the input plane. The dependence of the real power of the full Gaussian light wave on b(t)/b and w0/lambda is examined. For a specified w0/lambda, the reactive power, which can be positive or negative, increases as b(t)/b is increased from 0 to 1 and becomes infinite for b(t)/b=1. For a specified b(t)/b, the reactive power approaches zero as kw0 is increased and reaches the limiting value of zero of the paraxial beam.

  17. Voltage Control in Distribution Systems Considered Reactive Power Output Sharing

    NASA Astrophysics Data System (ADS)

    Oshiro, Masato; Senjyu, Tomonobu; Yona, Atsushi; Urasaki, Naomitsu; Funabashi, Toshihisa

    In recent years, distributed generation (DG) and renewable energy source (RES) are attracting special attention to distribution systems. Renewable energy such as photovoltaic (PV) system and wind turbine generator are used as a source of clean energy. However, the large amount of distributed generation causes voltage deviation beyond a statutory range in distribution systems. This paper proposes a methodology for voltage control by using inverters interfaced with DG and tap changing transformers. In the proposed method a one-day schedule of voltage references for the control devices are determined by an optimization technique based on predicted values of load demand and PV power generation. Furthermore, decided reactive power output according to the locally measurable voltage based on droop characteristic. Slope and base value on droop characteristic are selected by fuzzy control. The proposed method accomplishes improvement against voltage distribution considered the reactive power output sharing and reduction of distribution loss. The effectiveness of the proposed method is verified by using MATLAB®.

  18. Application of Newton's optimal power flow in voltage/reactive power control

    SciTech Connect

    Bjelogrlic, M.; Babic, B.S. ); Calovic, M.S. ); Ristanovic, P. )

    1990-11-01

    This paper considers an application of Newton's optimal power flow to the solution of the secondary voltage/reactive power control in transmission networks. An efficient computer program based on the latest achievements in the sparse matrix/vector techniques has been developed for this purpose. It is characterized by good robustness, accuracy and speed. A combined objective function appropriate for various system load levels with suitable constraints, for treatment of the power system security and economy is also proposed. For the real-time voltage/reactive power control, a suboptimal power flow procedure has been derived by using the reduced set of control variables. This procedure is based on the sensitivity theory applied to the determination of zones for the secondary voltage/reactive power control and corresponding reduced set of regulating sources, whose reactive outputs represent control variables in the optimal power flow program. As a result, the optimal power flow program output becomes a schedule to be used by operators in the process of the real-time voltage/reactive power control in both normal and emergency operating states.

  19. Minimization of Reactive Power Fluctuation in JT-60SA Magnet Power Supply

    NASA Astrophysics Data System (ADS)

    Shimada, K.; Terakado, T.; Yamauchi, K.; Matsukawa, M.; Baulaigue, O.; Coletti, R.; Coletti, A.; Novello, L.

    2013-02-01

    This paper describes an asymmetric control method for the firing angle and a start/stop timing shift control of four thyristor converters called “Booster PS" to minimize the reactive power fluctuation during plasma initiation in JT-60SA. From the simulation using the “PSCAD/EMTDC" code, it is found that these control methods can drastically reduce the reactive power induced by the four units of the “Booster PS". In addition, the voltage fluctuation of the motor-generator connected to the “Booster PS" is expected to be suppressed. This can also contribute to achieve stable control of the JT-60SA magnet power supplies.

  20. A Single-Phase Current Source Solar Inverter with Constant Instantaneous Power, Improved Reliability, and Reduced-Size DC-Link Filter

    NASA Astrophysics Data System (ADS)

    Bush, Craig R.

    This dissertation presents a novel current source converter topology that is primarily intended for single-phase photovoltaic (PV) applications. In comparison with the existing PV inverter technology, the salient features of the proposed topology are: a) the low frequency (double of line frequency) ripple that is common to single-phase inverters is greatly reduced; b) the absence of low frequency ripple enables significantly reduced size pass components to achieve necessary DC-link stiffness and c) improved maximum power point tracking (MPPT) performance is readily achieved due to the tightened current ripple even with reduced-size passive components. The proposed topology does not utilize any electrolytic capacitors. Instead an inductor is used as the DC-link filter and reliable AC film capacitors are utilized for the filter and auxiliary capacitor. The proposed topology has a life expectancy on par with PV panels. The proposed modulation technique can be used for any current source inverter where an unbalanced three-phase operation is desires such as active filters and power controllers. The proposed topology is ready for the next phase of microgrid and power system controllers in that it accepts reactive power commands. This work presents the proposed topology and its working principle supported by with numerical verifications and hardware results. Conclusions and future work are also presented.

  1. Method of measuring reactive acoustic power density in a fluid

    DOEpatents

    Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

    1985-01-01

    A method for determining reactive acoustic power density level and its direction in a fluid using a single sensor is disclosed. In the preferred embodiment, an apparatus for conducting the method, which is termed a thermoacoustic couple, consists of a stack of thin, spaced apart polymeric plates, selected ones of which include multiple bimetallic thermocouple junctions positioned along opposite end edges thereof. The thermocouple junctions are connected in series in the nature of a thermopile, and are arranged so as to be responsive to small temperature differences between the opposite edges of the plates. The magnitude of the temperature difference, as represented by the magnitude of the electrical potential difference generated by the thermopile, is found to be directly related to the level of acoustic power density in the gas.

  2. Method of measuring reactive acoustic power density in a fluid

    DOEpatents

    Wheatley, J.C.; Swift, G.W.; Migliori, A.

    1985-09-03

    A method for determining reactive acoustic power density level and its direction in a fluid using a single sensor is disclosed. In the preferred embodiment, an apparatus for conducting the method, which is termed a thermoacoustic couple, consists of a stack of thin, spaced apart polymeric plates, selected ones of which include multiple bimetallic thermocouple junctions positioned along opposite end edges thereof. The thermocouple junctions are connected in series in the nature of a thermopile, and are arranged so as to be responsive to small temperature differences between the opposite edges of the plates. The magnitude of the temperature difference, as represented by the magnitude of the electrical potential difference generated by the thermopile, is found to be directly related to the level of acoustic power density in the gas. 5 figs.

  3. Short-term scheduling of reactive power controllers

    SciTech Connect

    Hong Yingyi; Liao Csongming

    1995-05-01

    A two-level approach is presented to solve the problem of optimal short-term (one day) scheduling of reactive power controllers in this paper. The entire problem is decomposed into two levels: the master and the slave levels. The master level deals with minimization of the depreciation cost of compensators and EHV transformer taps in order to reduce the control action for compensators and EHV transformer taps while satisfying operating constraints. The slave level treats minimization of capitalized MW losses while satisfying system security constraints. The slave level also treats OLTCs and determines scheduling of the generator voltages. These two levels interact through linear constraints in the iteration process. A practical 265-bus system, namely Taiwan Power System, are used to serve as a sample to show the applicability of the presented approach.

  4. 78 FR 77670 - Zero Rate Reactive Power Rate Schedules; Notice Allowing Post-Workshop Comments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-24

    ... Comments On December 11, 2013, a Commission staff-led workshop explored the mechanics of filing reactive... written comments focused on the mechanics of filing reactive power rate schedules for which there is...

  5. Secure provision of reactive power ancillary services in competitive electricity markets

    NASA Astrophysics Data System (ADS)

    El-Samahy, Ismael

    The research work presented in this thesis discusses various complex issues associated with reactive power management and pricing in the context of new operating paradigms in deregulated power systems, proposing appropriate policy solutions. An integrated two-level framework for reactive power management is set forth, which is both suitable for a competitive market and ensures a secure and reliable operation of the associated power system. The framework is generic in nature and can be adopted for any electricity market structure. The proposed hierarchical reactive power market structure comprises two stages: procurement of reactive power resources on a seasonal basis, and real-time reactive power dispatch. The main objective of the proposed framework is to provide appropriate reactive power support from service providers at least cost, while ensuring a secure operation of the power system. The proposed procurement procedure is based on a two-step optimization model. First, the marginal benefits of reactive power supply from each provider, with respect to system security, are obtained by solving a loadability-maximization problem subject to transmission security constraints imposed by voltage and thermal limits. Second, the selected set of generators is determined by solving an optimal power flow (OPF)-based auction. This auction maximizes a societal advantage function comprising generators' offers and their corresponding marginal benefits with respect to system security, and considering all transmission system constraints. The proposed procedure yields the selected set of generators and zonal price components, which would form the basis for seasonal contracts between the system operator and the selected reactive power service providers. The main objective of the proposed reactive power dispatch model is to minimize the total payment burden on the Independent System Operator (ISO), which is associated with reactive power dispatch. The real power generation is

  6. Advanced configuration of hybrid passive filter for reactive power and harmonic compensation.

    PubMed

    Kececioglu, O Fatih; Acikgoz, Hakan; Sekkeli, Mustafa

    2016-01-01

    Harmonics is one of the major power quality problems for power systems. The harmonics can be eliminated by power filters such as passive, active, and hybrid. In this study, a new passive filter configuration has been improved in addition to the existing passive filter configurations. Conventional hybrid passive filters are not successful to compensate rapidly changing reactive power demand. The proposed configure are capable of compensating both harmonics and reactive power at the same time. Simulation results show that performance of reactive power and harmonic compensation with advanced hybrid passive filter is better than conventional hybrid passive filters. PMID:27536512

  7. Local Dynamic Reactive Power for Correction of System Voltage Problems

    SciTech Connect

    Kueck, John D; Rizy, D Tom; Li, Fangxing; Xu, Yan; Li, Huijuan; Adhikari, Sarina; Irminger, Philip

    2008-12-01

    Distribution systems are experiencing outages due to a phenomenon known as local voltage collapse. Local voltage collapse is occurring in part because modern air conditioner compressor motors are much more susceptible to stalling during a voltage dip than older motors. These motors can stall in less than 3 cycles (.05s) when a fault, such as on the sub-transmission system, causes voltage to sag to 70 to 60%. The reasons for this susceptibility are discussed in the report. During the local voltage collapse, voltages are depressed for a period of perhaps one or two minutes. There is a concern that these local events are interacting together over larger areas and may present a challenge to system reliability. An effective method of preventing local voltage collapse is the use of voltage regulation from Distributed Energy Resources (DER) that can supply or absorb reactive power. DER, when properly controlled, can provide a rapid correction to voltage dips and prevent motor stall. This report discusses the phenomenon and causes of local voltage collapse as well as the control methodology we have developed to counter voltage sag. The problem is growing because of the use of low inertia, high efficiency air conditioner (A/C) compressor motors and because the use of electric A/C is growing in use and becoming a larger percentage of system load. A method for local dynamic voltage regulation is discussed which uses reactive power injection or absorption from local DER. This method is independent, rapid, and will not interfere with conventional utility system voltage control. The results of simulations of this method are provided. The method has also been tested at the ORNL s Distributed Energy Communications and Control (DECC) Laboratory using our research inverter and synchronous condenser. These systems at the DECC Lab are interconnected to an actual distribution system, the ORNL distribution system, which is fed from TVA s 161kV sub-transmission backbone. The test results

  8. Distance Relaying with Power Swing Detection based on Voltage and Reactive Power Sensitivity

    NASA Astrophysics Data System (ADS)

    Patel, Ujjaval J.; Chothani, Nilesh G.; Bhatt, Praghnesh J.

    2016-02-01

    Sudden changes in loading or configuration of an electrical network causes power swing which may result in an unwanted tripping of the distance relay. Hence, it becomes utmost necessary to rapidly and reliably discriminate between actual fault and power swing conditions in order to prevent instability in power network due to mal operation of distance relay. This paper proposes a novel method for the discrimination between fault and power swing based on rate of change of voltage and reactive power measured at relay location. The effectiveness of the proposed algorithm is evaluated by simulating series of power swing conditions in PSCAD/EMTDC® software for different disturbances such as change in mechanical power input to synchronous generator, tripping of parallel line due to fault and sudden application of heavy load. It is revealed that the distance relay gives successful tripping in case of different fault conditions and remains inoperative for power swing with the implementation of the proposed algorithm. Moreover, the proposed scheme has ability to distinguish the symmetrical and asymmetrical fault occurrence during power swing condition.

  9. Reactive compatibilizer-tracer: A powerful tool for designing, scaling up and optimizing reactive blending processes

    NASA Astrophysics Data System (ADS)

    Ji, Wei-Yun; Feng, Lian-Fang; Zhang, Cai-Liang; Hu, Guo-Hua

    2015-05-01

    A concept of reactive compatibilizer-tracer is developed to study reactive polymer blending processes in a twin screw extruder. It is summarized as follows. Fluorescent moieties such as anthracene are attached to a reactive compatibilizer so that the latter can be served both as a compatibilizer and a tracer. When evaluating its compatibilizing efficiency for a polymer blending system, unlike the polymer components of the blend which are continuously fed to the extruder, the reactive compatibilizer-tracer is added as a pulse. The concentration of the reactive compatibilizer-tracer in the polymer blend at the die exit is measured, in-line and in real time, using probes capable of detecting the signal of the emission of fluorescent moieties of the reactive compatibilizer-tracer. In the meantime, the corresponding size of the dispersed phase domains of the blend is determined off-line. These two pieces of information allow assessing the compatibilizing efficiency of a reactive compatibilizer in a much easier manner and using a much smaller amount of compatibilizer. Consequently, the concept of reactive compatibilizer-tracer can help select most appropriate compatibilizers under real industrial polymer blending conditions as well as scaling up and/or optimizing them.

  10. Energy Storage and Reactive Power Compensator in a Large Wind Farm: Preprint

    SciTech Connect

    Muljadi, E.; Butterfield, C. P.; Yinger, R.; Romanowitz, H.

    2003-10-01

    The size of wind farm power systems is increasing, and so is the number of wind farms contributing to the power systems network. The size of wind turbines is also increasing--from less than 1 MW a few years ago to the 2- to 3-MW machines being installed today and the 5-MW machines under development. The interaction of the wind farm, energy storage, reactive power compensation, and the power system network is being investigated. Because the loads and the wind farms' output fluctuate during the day, the use of energy storage and reactive power compensation is ideal for the power system network. Energy storage and reactive power compensation can minimize real/reactive power imbalances that can affect the surrounding power system. In this paper, we will show how the contribution of wind farms affects the power distribution network and how the power distribution network, energy storage, and reactive power compensation interact when the wind changes. We will also investigate the size of the components in relation to each other and to the power system.

  11. Assessment of the Economic Potential of Microgrids for Reactive Power Supply

    SciTech Connect

    Appen, Jan von; Marnay, Chris; Stadler, Michael; Momber, Ilan; Klapp, David; Scheven, Alexander von

    2011-05-01

    As power generation from variable distributed energy resources (DER) grows, energy flows in the network are changing, increasing the requirements for ancillary services, including voltage support. With the appropriate power converter, DER can provide ancillary services such as frequency control and voltage support. This paper outlines the economic potential of DERs coordinated in a microgrid to provide reactive power and voltage support at its point of common coupling. The DER Customer Adoption Model assesses the costs of providing reactive power, given local utility rules. Depending on the installed DER, the cost minimizing solution for supplying reactive power locally is chosen. Costs include the variable cost of the additional losses and the investment cost of appropriately over-sizing converters or purchasing capacitors. A case study of a large health care building in San Francisco is used to evaluate different revenue possibilities of creating an incentive for microgrids to provide reactive power.

  12. Reactive Inkjet Printing: Reactive Inkjet Printing of Biocompatible Enzyme Powered Silk Micro-Rockets (Small 30/2016).

    PubMed

    Gregory, David A; Zhang, Yu; Smith, Patrick J; Zhao, Xiubo; Ebbens, Stephen J

    2016-08-01

    On page 4048, X. Zhao, S. J. Ebbens, and co-workers demonstrate the ability to fabricate biocompatible silk microrockets via reactive inkjet printing. The microrockets are powered by catalase and undergo bubble propulsion in the presence of hydrogen peroxide. Microrockets are capable of swimming in a large variety of media including biological solutions. Inkjet printing allows digital definition of enzyme distribution within the silk scaffold to control rocket directionality. PMID:27492495

  13. Perspective on fossil power plant layup and reactivation

    SciTech Connect

    Tsou, J.L.

    1996-12-31

    In recent years, many utilities have developed excess generation capacity problems during period of low system load growth, particularly with new generation units coming on-line. System load studies may indicate that the situation is temporary and higher generation capacity will be needed in the near future. The objective of layup is to prevent component deterioration during the long shut down periods. This paper discusses equipment preservation practices in use by the electric utility industry and the advantages/disadvantages of various layup methods. Other issues related to plant layup and reactivation are also presented.

  14. The instantaneous frequency rate spectrogram

    NASA Astrophysics Data System (ADS)

    Czarnecki, Krzysztof

    2016-01-01

    An accelerogram of the instantaneous phase of signal components referred to as an instantaneous frequency rate spectrogram (IFRS) is presented as a joint time-frequency distribution. The distribution is directly obtained by processing the short-time Fourier transform (STFT) locally. A novel approach to amplitude demodulation based upon the reassignment method is introduced as a useful by-product. Additionally, an estimator of energy density versus the instantaneous frequency rate (IFR) is proposed and referred to as the IFR profile. The energy density is estimated based upon both the classical energy spectrogram and the IFRS smoothened by the median filter. Moreover, the impact of an analyzing window width, additive white Gaussian noise and observation time is tested. Finally, the introduced method is used for the analysis of the acoustic emission of an automotive engine. The recording of the engine of a Lamborghini Gallardo is analyzed as an example.

  15. On the Sequential Control of ITER Poloidal Field Converters for Reactive Power Reduction

    NASA Astrophysics Data System (ADS)

    Yuan, Hongwen; Fu, Peng; Gao, Ge; Huang, Liansheng; Song, Zhiquan; He, Shiying; Wu, Yanan; Dong, Lin; Wang, Min; Fang, Tongzhen

    2014-12-01

    Sequential control applied to the International Thermonuclear Experimental Reactor (ITER) poloidal field converter system for the purpose of reactive power reduction is the subject of this investigation. Due to the inherent characteristics of thyristor-based phase-controlled converter, the poloidal field converter system consumes a huge amount of reactive power from the grid, which subsequently results in a voltage drop at the 66 kV busbar if no measure is taken. The installation of a static var compensator rated for 750 MVar at the 66 kV busbar is an essential way to compensate reactive power to the grid, which is the most effective measure to solve the problem. However, sequential control of the multi-series converters provides an additional method to improve the natural power factor and thus alleviate the pressure of reactive power demand of the converter system without any additional cost. In the present paper, by comparing with the symmetrical control technique, the advantage of sequential control in reactive power consumption is highlighted. Simulation results based on SIMULINK are found in agreement with the theoretical analysis.

  16. 78 FR 63176 - Notice Announcing Workshop; Zero Rate Reactive Power Rate Schedules

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Notice Announcing Workshop; Zero Rate Reactive Power Rate Schedules Concurrent with this notice, the Commission is issuing an order in Chehalis Power Generating, L.P., Docket...

  17. Reactive ion etching of silicon using low-power plasma etcher

    NASA Astrophysics Data System (ADS)

    Veselov, D. S.; Bakun, A. D.; Voronov, Yu A.

    2016-09-01

    The paper is devoted to the study of deep reactive ion etching of silicon using diode plasma etcher system with a low-power source. Silicon wafers were etched in a sulfur hexafluoride plasma and sulfur hexafluoride/oxygen plasma. The maximum achieved silicon etch rate was about 2 μm/min. The expediency of using dry reactive ion etching in combination with wet anisotropic etching of silicon for manufacturing of microelectromechanical systems (MEMS) was demonstrated.

  18. A Wolf Pack Algorithm for Active and Reactive Power Coordinated Optimization in Active Distribution Network

    NASA Astrophysics Data System (ADS)

    Zhuang, H. M.; Jiang, X. J.

    2016-08-01

    This paper presents an active and reactive power dynamic optimization model for active distribution network (ADN), whose control variables include the output of distributed generations (DGs), charge or discharge power of energy storage system (ESS) and reactive power from capacitor banks. To solve the high-dimension nonlinear optimization model, a new heuristic swarm intelligent method, namely wolf pack algorithm (WPA) with better global convergence and computational robustness, is adapted so that the network loss minimization can be achieved. In this paper, the IEEE33-bus system is used to show the effectiveness of WPA technique compared with other techniques. Numerical tests on the modified IEEE 33-bus system show that WPA for active and reactive multi-period optimization of ADN is exact and effective.

  19. EV/PHEV Bidirectional Charger Assessment for V2G Reactive Power Operation

    SciTech Connect

    Kisacikoglu, Mithat C; Ozpineci, Burak; Tolbert, Leon M

    2013-01-01

    This paper presents a summary of the available single-phase ac-dc topologies used for EV/PHEV, level-1 and -2 on-board charging and for providing reactive power support to the utility grid. It presents the design motives of single-phase on-board chargers in detail and makes a classification of the chargers based on their future vehicle-to-grid usage. The pros and cons of each different ac-dc topology are discussed to shed light on their suitability for reactive power support. This paper also presents and analyzes the differences between charging-only operation and capacitive reactive power operation that results in increased demand from the dc-link capacitor (more charge/discharge cycles and increased second harmonic ripple current). Moreover, battery state of charge is spared from losses during reactive power operation, but converter output power must be limited below its rated power rating to have the same stress on the dc-link capacitor.

  20. Reactive power interconnection requirements for PV and wind plants : recommendations to NERC.

    SciTech Connect

    McDowell, Jason; Walling, Reigh; Peter, William; Von Engeln, Edi; Seymour, Eric; Nelson, Robert; Casey, Leo; Ellis, Abraham; Barker, Chris.

    2012-02-01

    Voltage on the North American bulk system is normally regulated by synchronous generators, which typically are provided with voltage schedules by transmission system operators. In the past, variable generation plants were considered very small relative to conventional generating units, and were characteristically either induction generator (wind) or line-commutated inverters (photovoltaic) that have no inherent voltage regulation capability. However, the growing level of penetration of non-traditional renewable generation - especially wind and solar - has led to the need for renewable generation to contribute more significantly to power system voltage control and reactive power capacity. Modern wind-turbine generators, and increasingly PV inverters as well, have considerable dynamic reactive power capability, which can be further enhanced with other reactive support equipment at the plant level to meet interconnection requirements. This report contains a set of recommendations to the North-America Electricity Reliability Corporation (NERC) as part of Task 1-3 (interconnection requirements) of the Integration of Variable Generation Task Force (IVGTF) work plan. The report discusses reactive capability of different generator technologies, reviews existing reactive power standards, and provides specific recommendations to improve existing interconnection standards.

  1. 78 FR 63177 - Order on Voluntary Remand and Clarifying Policy on Filing of Reactive Power Service Rate...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    ... Generation Sources Service (reactive power) to the Bonneville Power Administration (Bonneville or BPA) is a....'' \\5\\ The Commission stated that ``Chehalis has been providing reactive power to BPA pursuant to an... interconnection agreement between Chehalis and BPA was required to be filed prior to May 2005, even though it...

  2. Reactive power planning under high penetration of wind energy using Benders decomposition

    DOE PAGESBeta

    Xu, Yan; Wei, Yanli; Fang, Xin; Li, Fangxing; Azim, Riyasat

    2015-11-05

    This study addresses the optimal allocation of reactive power volt-ampere reactive (VAR) sources under the paradigm of high penetration of wind energy. Reactive power planning (RPP) in this particular condition involves a high level of uncertainty because of wind power characteristic. To properly model wind generation uncertainty, a multi-scenario framework optimal power flow that considers the voltage stability constraint under the worst wind scenario and transmission N 1 contingency is developed. The objective of RPP in this study is to minimise the total cost including the VAR investment cost and the expected generation cost. Therefore RPP under this condition ismore » modelled as a two-stage stochastic programming problem to optimise the VAR location and size in one stage, then to minimise the fuel cost in the other stage, and eventually, to find the global optimal RPP results iteratively. Benders decomposition is used to solve this model with an upper level problem (master problem) for VAR allocation optimisation and a lower problem (sub-problem) for generation cost minimisation. Impact of the potential reactive power support from doubly-fed induction generator (DFIG) is also analysed. Lastly, case studies on the IEEE 14-bus and 118-bus systems are provided to verify the proposed method.« less

  3. Reactive power planning under high penetration of wind energy using Benders decomposition

    SciTech Connect

    Xu, Yan; Wei, Yanli; Fang, Xin; Li, Fangxing; Azim, Riyasat

    2015-11-05

    This study addresses the optimal allocation of reactive power volt-ampere reactive (VAR) sources under the paradigm of high penetration of wind energy. Reactive power planning (RPP) in this particular condition involves a high level of uncertainty because of wind power characteristic. To properly model wind generation uncertainty, a multi-scenario framework optimal power flow that considers the voltage stability constraint under the worst wind scenario and transmission N 1 contingency is developed. The objective of RPP in this study is to minimise the total cost including the VAR investment cost and the expected generation cost. Therefore RPP under this condition is modelled as a two-stage stochastic programming problem to optimise the VAR location and size in one stage, then to minimise the fuel cost in the other stage, and eventually, to find the global optimal RPP results iteratively. Benders decomposition is used to solve this model with an upper level problem (master problem) for VAR allocation optimisation and a lower problem (sub-problem) for generation cost minimisation. Impact of the potential reactive power support from doubly-fed induction generator (DFIG) is also analysed. Lastly, case studies on the IEEE 14-bus and 118-bus systems are provided to verify the proposed method.

  4. Bridge capacitor bank installation concept reactive power generation in EHV systems

    SciTech Connect

    Andrei, R.G.; Keri, A.J.F.; Albanese, R.J.; Johnson, P.B. )

    1993-11-01

    As an alternative to the conventional shunt capacitor bank installation, a totally new concept of providing reactive power to an electrical power system is presented. A new type of capacitor bank installation called bridge'' is described. An analytical investigation of the bridge capacitor installation concept and its application in an EHV electrical power system is presented. The technical and economic advantages of the bridge capacitor bank over the shunt capacitor bank are analyzed in the context of the reactive power being directly supplied to an EHV system. A field trial installation at a lower than EHV level (138/69kV) along with some experimental test results are presented in the last part of this paper. A more detailed presentation of the field experience with the trial installation will be covered in a future paper.

  5. A new dynamic voltage restorer with separating active and reactive power circuit design

    NASA Astrophysics Data System (ADS)

    Pai, Fu-Sheng

    2015-05-01

    Conventional dynamic voltage restorers (DVRs) install parallel battery and capacitor sets at the DC bus to supply the required power for voltage sag compensation. However, the reactive power output of a DVR may increase the ripple voltage at the inner DC bus, possibly resulting in a higher operating temperature of the battery and thus decreased battery life. This paper proposes a DVR system that uses a cascade power module to effectively compensate voltage sag. By separating the active and reactive compensation powers, the proposed DVR provides a lower ripple DC link for extending battery life and offers a flexible way to design the capacitor bank. To confirm the effectiveness of the proposed design, theoretical analysis and experimental validation were conducted under various scenarios. Test results confirm the feasibility and practicality of the proposed method.

  6. Real Power and Reactive Power Control of a Three-Phase Single-Stage-PV System and PV voltage Stability

    SciTech Connect

    Li, Huijuan; Xu, Yan; Adhikari, Sarina; Rizy, D Tom; Li, Fangxing; Irminger, Philip

    2012-01-01

    Grid-connected photovoltaic (PV) systems with power electronic interfaces can provide both real and reactive power to meet power system needs with appropriate control algorithms. This paper presents the control algorithm design for a three-phase single-stage grid-connected PV inverter to achieve either maximum power point tracking (MPPT) or a certain amount of real power injection, as well as the voltage/var control. The switching between MPPT control mode and a certain amount of real power control mode is automatic and seamless. Without the DC-to-DC booster stage, PV DC voltage stability is an important issue in the control design especially when the PV inverter is operating at maximum power point (MPP) with voltage/var control. The PV DC voltage collapse phenomenon and its reason are discussed. The method based on dynamic correction of the PV inverter output is proposed to ensure PV DC voltage stability. Simulation results of the single-stage PV system during system disturbances and fast solar irradiation changes confirm that the proposed control algorithm for single-stage PV inverters can provide appropriate real and reactive power services and ensure PV DC voltage stability during dynamic system operation and atmospheric conditions.

  7. 77 FR 21555 - Reactive Power Resources; Supplemental Notice of Technical Conference

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-10

    ... Interconnection Studies. This panel will discuss: Methods used to determine the reactive power requirements for a... Robert Jenkins, Director--Utility Interconnection, First Solar Kris Zadlo, Vice President, Invenergy..., transmission resources and energy storage resources; The design options for and cost of installing...

  8. 78 FR 72673 - Zero Rate Reactive Power Rate Schedules; Notice of Staff Workshop

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-03

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Zero Rate Reactive Power Rate Schedules; Notice of Staff Workshop This.... to 4 p.m. at the Federal Energy Regulatory Commission, 888 First Street NE., Washington, DC...

  9. 78 FR 75562 - Zero Rate Reactive Power Rate Schedules; Notice of Staff Workshop

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Zero Rate Reactive Power Rate Schedules; Notice of Staff Workshop This... on December 11, 2013 from 1:30 p.m. to 4 p.m. at the Federal Energy Regulatory Commission, 888...

  10. A parametric model for reactive high-power impulse magnetron sputtering of films

    NASA Astrophysics Data System (ADS)

    Kozák, Tomáš; Vlček, Jaroslav

    2016-02-01

    We present a time-dependent parametric model for reactive HiPIMS deposition of films. Specific features of HiPIMS discharges and a possible increase in the density of the reactive gas in front of the reactive gas inlets placed between the target and the substrate are considered in the model. The model makes it possible to calculate the compound fractions in two target layers and in one substrate layer, and the deposition rate of films at fixed partial pressures of the reactive and inert gas. A simplified relation for the deposition rate of films prepared using a reactive HiPIMS is presented. We used the model to simulate controlled reactive HiPIMS depositions of stoichiometric \\text{Zr}{{\\text{O}}2} films, which were recently carried out in our laboratories with two different configurations of the {{\\text{O}}2} inlets in front of the sputtered target. The repetition frequency was 500 Hz at the deposition-averaged target power densities of 5 Wcm-2and 50 Wcm-2 with a pulse-averaged target power density up to 2 kWcm-2. The pulse durations were 50 μs and 200 μs. Our model calculations show that the to-substrate {{\\text{O}}2} inlet provides systematically lower compound fractions in the target surface layer and higher compound fractions in the substrate surface layer, compared with the to-target {{\\text{O}}2} inlet. The low compound fractions in the target surface layer (being approximately 10% at the deposition-averaged target power density of 50 Wcm-2 and the pulse duration of 200 μs) result in high deposition rates of the films produced, which are in agreement with experimental values.

  11. Optimal reactive power planning for distribution systems considering intermittent wind power using Markov model and genetic algorithm

    NASA Astrophysics Data System (ADS)

    Li, Cheng

    Wind farms, photovoltaic arrays, fuel cells, and micro-turbines are all considered to be Distributed Generation (DG). DG is defined as the generation of power which is dispersed throughout a utility's service territory and either connected to the utility's distribution system or isolated in a small grid. This thesis addresses modeling and economic issues pertaining to the optimal reactive power planning for distribution system with wind power generation (WPG) units. Wind farms are inclined to cause reverse power flows and voltage variations due to the random-like outputs of wind turbines. To deal with this kind of problem caused by wide spread usage of wind power generation, this thesis investigates voltage and reactive power controls in such a distribution system. Consequently static capacitors (SC) and transformer taps are introduced into the system and treated as controllers. For the purpose of getting optimum voltage and realizing reactive power control, the research proposes a proper coordination among the controllers like on-load tap changer (OLTC), feeder-switched capacitors. What's more, in order to simulate its uncertainty, the wind power generation is modeled by the Markov model. In that way, calculating the probabilities for all the scenarios is possible. Some outputs with consecutive and discrete values have been used for transition between successive time states and within state wind speeds. The thesis will describe the method to generate the wind speed time series from the transition probability matrix. After that, utilizing genetic algorithm, the optimal locations of SCs, the sizes of SCs and transformer taps are determined so as to minimize the cost or minimize the power loss, and more importantly improve voltage profiles. The applicability of the proposed method is verified through simulation on a 9-bus system and a 30-bus system respectively. At last, the simulation results indicate that as long as the available capacitors are able to sufficiently

  12. Asymptotic Rayleigh instantaneous unit hydrograph

    USGS Publications Warehouse

    Troutman, B.M.; Karlinger, M.R.

    1988-01-01

    The instantaneous unit hydrograph for a channel network under general linear routing and conditioned on the network magnitude, N, tends asymptotically, as N grows large, to a Rayleigh probability density function. This behavior is identical to that of the width function of the network, and is proven under the assumption that the network link configuration is topologically random and the link hydraulic and geometric properties are independent and identically distributed random variables. The asymptotic distribution depends only on a scale factor, {Mathematical expression}, where ?? is a mean link wave travel time. ?? 1988 Springer-Verlag.

  13. Reactive power generation in high speed induction machines by continuously occurring space-transients

    NASA Astrophysics Data System (ADS)

    Laithwaite, E. R.; Kuznetsov, S. B.

    1980-09-01

    A new technique of continuously generating reactive power from the stator of a brushless induction machine is conceived and tested on a 10-kw linear machine and on 35 and 150 rotary cage motors. An auxiliary magnetic wave traveling at rotor speed is artificially created by the space-transient attributable to the asymmetrical stator winding. At least two distinct windings of different pole-pitch must be incorporated. This rotor wave drifts in and out of phase repeatedly with the stator MMF wave proper and the resulting modulation of the airgap flux is used to generate reactive VA apart from that required for magnetization or leakage flux. The VAR generation effect increases with machine size, and leading power factor operation of the entire machine is viable for large industrial motors and power system induction generators.

  14. Movable-molybdenum-reflector reactivity experiments for control studies of compact space power reactor concepts

    NASA Technical Reports Server (NTRS)

    Fox, T. A.

    1973-01-01

    An experimental reflector reactivity study was made with a compact cylindrical reactor using a uranyl fluoride - water fuel solution. The reactor was axially unreflected and radially reflected with segments of molybdenum. The reflector segments were displaced incrementally in both the axial and radial dimensions, and the shutdown of each configuration was measured by using the pulsed-neutron source technique. The reactivity effects for axial and radial displacement of reflector segments are tabulated separately and compared. The experiments provide data for control-system studies of compact-space-power-reactor concepts.

  15. Some Statistics of Instantaneous Precipitation.

    NASA Astrophysics Data System (ADS)

    Jones, Douglas M. A.; Wendland, Wayne M.

    1984-09-01

    Known sources of data from arrays of instantaneous precipitation intensity recorders in southern Germany, east-central Illinois, northeastern Illinois, central Florida, and Hilo, Hawaii are obtained. These data are analyzed for line averages of the percent frequency of occurrence of the exceedance of selected threshold precipitation intensities. The correlation coefficients of the precipitation intensity at sites at varying distances from a reference site are determined. The decay in correlation is found to be a function of climatic region and the type of precipitation: showery or continuous. Showery rains are found to be essentially uncorrelated about 12 km from the reference site while continuous rain exhibits no correlation beyond about 50 km.Single-station intensity data collected at Urbana, Illinois; Paris, France; Inyanga, Zimbabwe; Bogor, Indonesia; Reading, United Kingdom; Island Beach, New Jersey; Miami, Florida; Franklin, North Carolina; and Majuro, Marshall Islands, are compared.

  16. A Preliminary Analysis of the Economics of Using Distributed Energy as a Source of Reactive Power Supply

    SciTech Connect

    Li, Fangxing; Kueck, John D; Rizy, D Tom; King, Thomas F

    2006-04-01

    A major blackout affecting 50 million people in the Northeast United States, where insufficient reactive power supply was an issue, and an increased number of filings made to the Federal Energy Regulatory Commission by generators for reactive power has led to a closer look at reactive power supply and compensation. The Northeastern Massachusetts region is one such area where there is an insufficiency in reactive power compensation. Distributed energy due to its close proximity to loads seems to be a viable option for solving any present or future reactive power shortage problems. Industry experts believe that supplying reactive power from synchronized distributed energy sources can be 2 to 3 times more effective than providing reactive support in bulk from longer distances at the transmission or generation level. Several technology options are available to supply reactive power from distributed energy sources such as small generators, synchronous condensers, fuel cells or microturbines. In addition, simple payback analysis indicates that investments in DG to provide reactive power can be recouped in less than 5 years when capacity payments for providing reactive power are larger than $5,000/kVAR and the DG capital and installation costs are lower than $30/kVAR. However, the current institutional arrangements for reactive power compensation present a significant barrier to wider adoption of distributed energy as a source of reactive power. Furthermore, there is a significant difference between how generators and transmission owners/providers are compensated for reactive power supplied. The situation for distributed energy sources is even more difficult, as there are no arrangements to compensate independent DE owners interested in supplying reactive power to the grid other than those for very large IPPs. There are comparable functionality barriers as well, as these smaller devices do not have the control and communications requirements necessary for automatic

  17. TLBO based Voltage Stable Environment Friendly Economic Dispatch Considering Real and Reactive Power Constraints

    NASA Astrophysics Data System (ADS)

    Verma, H. K.; Mafidar, P.

    2013-09-01

    In view of growing concern towards environment, power system engineers are forced to generate quality green energy. Hence the economic dispatch (ED) aims at the power generation to meet the load demand at minimum fuel cost with environmental and voltage constraints along with essential constraints on real and reactive power. The emission control which reduces the negative impact on environment is achieved by including the additional constraints in ED problem. Presently, the power system mostly operates near its stability limits, therefore with increased demand the system faces voltage problem. The bus voltages are brought within limit in the present work by placement of static var compensator (SVC) at weak bus which is identified from bus participation factor. The optimal size of SVC is determined by univariate search method. This paper presents the use of Teaching Learning based Optimization (TLBO) algorithm for voltage stable environment friendly ED problem with real and reactive power constraints. The computational effectiveness of TLBO is established through test results over particle swarm optimization (PSO) and Big Bang-Big Crunch (BB-BC) algorithms for the ED problem.

  18. Efficient and Reliable Reactive Power Supply and Consumption --Insights from an Integrated Program of Engineering and EconomicResearch

    SciTech Connect

    Thomas, Robert J.; Mount, Timothy D.; Schuler, Richard; Schulze,William; Zimmerman, Ray; Alvarado, Fernando; Lesieutre, Bernard C.; Overholt, Philip N.; Eto, Joseph H.

    2008-01-01

    In 2005, the Federal Energy Regulatory Commission (FERC) began discussing regulatory policy for reactive-power procurement and pricing in competitive electricity markets. This paper summarizes findings from a unique, interdisciplinary program of public-interest research that lays a formal foundation for evaluating aspects of FERC staff recommendations and offers early insights that should be useful in guiding policy implementation, specifically by: (1) clarifying the consumers and economic characteristics of reactive power as a basis for creating incentives to appropriately price it, (2) defining specific challenges in creating a competitive market for reactive power as well as new tools needed to help ensure such a market functions efficiently, and (3) demonstrating the importance of accounting for the physical characteristics of the transmission network in planning for reactive power and avoiding the exercise of market power by suppliers.

  19. Regularization of Instantaneous Frequency Attribute Computations

    NASA Astrophysics Data System (ADS)

    Yedlin, M. J.; Margrave, G. F.; Van Vorst, D. G.; Ben Horin, Y.

    2014-12-01

    We compare two different methods of computation of a temporally local frequency:1) A stabilized instantaneous frequency using the theory of the analytic signal.2) A temporally variant centroid (or dominant) frequency estimated from a time-frequency decomposition.The first method derives from Taner et al (1979) as modified by Fomel (2007) and utilizes the derivative of the instantaneous phase of the analytic signal. The second method computes the power centroid (Cohen, 1995) of the time-frequency spectrum, obtained using either the Gabor or Stockwell Transform. Common to both methods is the necessity of division by a diagonal matrix, which requires appropriate regularization.We modify Fomel's (2007) method by explicitly penalizing the roughness of the estimate. Following Farquharson and Oldenburg (2004), we employ both the L curve and GCV methods to obtain the smoothest model that fits the data in the L2 norm.Using synthetic data, quarry blast, earthquakes and the DPRK tests, our results suggest that the optimal method depends on the data. One of the main applications for this work is the discrimination between blast events and earthquakesFomel, Sergey. " Local seismic attributes." , Geophysics, 72.3 (2007): A29-A33.Cohen, Leon. " Time frequency analysis theory and applications." USA: Prentice Hall, (1995).Farquharson, Colin G., and Douglas W. Oldenburg. "A comparison of automatic techniques for estimating the regularization parameter in non-linear inverse problems." Geophysical Journal International 156.3 (2004): 411-425.Taner, M. Turhan, Fulton Koehler, and R. E. Sheriff. " Complex seismic trace analysis." Geophysics, 44.6 (1979): 1041-1063.

  20. Mechanism of instantaneous coal outbursts

    SciTech Connect

    Guan, P.; Wang, H.Y.; Zhang, Y.X.

    2009-10-15

    Thousands of mine workers die every year from mining accidents, and instantaneous coal outbursts in underground coal mines are one of the major killers. Various models for these outbursts have been proposed, but the precise mechanism is still unknown. We hypothesize that the mechanism of coal outbursts is similar to magma fragmentation during explosive volcanic eruptions; i.e., it is caused by high gas pressure inside coal but low ambient pressure on it, breaking coal into pieces and releasing the high-pressure gas in a shock wave. Hence, coal outbursts may be regarded as another type of gas-driven eruption, in addition to explosive volcanic, lake, and possible ocean eruptions. We verify the hypothesis by experiments using a shock-tube apparatus. Knowing the mechanism of coal outbursts is the first step in developing prediction and mitigation measures. The new concept of gas-driven solid eruption is also important to a better understanding of salt-gas outbursts, rock-gas outbursts, and mud volcano eruptions.

  1. Proactive and Reactive Transmission Power Control for Energy-Efficient On-Body Communications

    PubMed Central

    Vallejo, Mónica; Recas, Joaquín.; Ayala, José L.

    2015-01-01

    In wireless body sensor network (WBSNs), the human body has an important effect on the performance of the communication due to the temporal variations caused and the attenuation and fluctuation of the path loss. This fact suggests that the transmission power must adapt to the current state of the link in a way that it ensures a balance between energy consumption and packet loss. In this paper, we validate our two transmission power level policies (reactive and predictive approaches) using the Castalia simulator. The integration of our experimental measurements in the simulator allows us to easily evaluate complex scenarios, avoiding the difficulties associated with a practical realization. Our results show that both schemes perform satisfactorily, providing overall energy savings of 24% and 22% for a case of study, as compared to the maximum transmission power mode. PMID:25769049

  2. Plasma reactivity in high-power impulse magnetron sputtering through oxygen kinetics

    SciTech Connect

    Vitelaru, Catalin; Lundin, Daniel; Brenning, Nils; Minea, Tiberiu

    2013-09-02

    The atomic oxygen metastable dynamics in a Reactive High-Power Impulse Magnetron Sputtering (R-HiPIMS) discharge has been characterized using time-resolved diode laser absorption in an Ar/O{sub 2} gas mixture with a Ti target. Two plasma regions are identified: the ionization region (IR) close to the target and further out the diffusion region (DR), separated by a transition region. The μs temporal resolution allows identifying the main atomic oxygen production and destruction routes, which are found to be very different during the pulse as compared to the afterglow as deduced from their evolution in space and time.

  3. Duty cycle control in reactive high-power impulse magnetron sputtering of hafnium and niobium

    NASA Astrophysics Data System (ADS)

    Ganesan, R.; Treverrow, B.; Murdoch, B.; Xie, D.; Ross, A. E.; Partridge, J. G.; Falconer, I. S.; McCulloch, D. G.; McKenzie, D. R.; Bilek, M. M. M.

    2016-06-01

    Instabilities in reactive sputtering have technological consequences and have been attributed to the formation of a compound layer on the target surface (‘poisoning’). Here we demonstrate how the duty cycle of high power impulse magnetron sputtering (HiPIMS) can be used to control the surface conditions of Hf and Nb targets. Variations in the time resolved target current characteristics as a function of duty cycle were attributed to gas rarefaction and to the degree of poisoning of the target surface. As the operation transitions from Ar driven sputtering to metal driven sputtering, the secondary electron emission changes and reduces the target current. The target surface transitions smoothly from a poisoned state at low duty cycles to a quasi-metallic state at high duty cycles. Appropriate selection of duty cycle increases the deposition rate, eliminates the need for active regulation of oxygen flow and enables stable reactive deposition of stoichiometric metal oxide films. A model is presented for the reactive HIPIMS process in which the target operates in a partially poisoned mode with different degrees of oxide layer distribution on its surface that depends on the duty cycle. Finally, we show that by tuning the pulse characteristics, the refractive indices of the metal oxides can be controlled without increasing the absorption coefficients, a result important for the fabrication of optical multilayer stacks.

  4. Testing of an Integrated Reactor Core Simulator and Power Conversion System with Simulated Reactivity Feedback

    NASA Technical Reports Server (NTRS)

    Bragg-Sitton, Shannon M.; Hervol, David S.; Godfroy, Thomas J.

    2010-01-01

    A Direct Drive Gas-Cooled (DDG) reactor core simulator has been coupled to a Brayton Power Conversion Unit (BPCU) for integrated system testing at NASA Glenn Research Center (GRC) in Cleveland, Ohio. This is a closed-cycle system that incorporates an electrically heated reactor core module, turboalternator, recuperator, and gas cooler. Nuclear fuel elements in the gas-cooled reactor design are replaced with electric resistance heaters to simulate the heat from nuclear fuel in the corresponding fast spectrum nuclear reactor. The thermodynamic transient behavior of the integrated system was the focus of this test series. In order to better mimic the integrated response of the nuclear-fueled system, a simulated reactivity feedback control loop was implemented. Core power was controlled by a point kinetics model in which the reactivity feedback was based on core temperature measurements; the neutron generation time and the temperature feedback coefficient are provided as model inputs. These dynamic system response tests demonstrate the overall capability of a non-nuclear test facility in assessing system integration issues and characterizing integrated system response times and response characteristics.

  5. Testing of an Integrated Reactor Core Simulator and Power Conversion System with Simulated Reactivity Feedback

    NASA Technical Reports Server (NTRS)

    Bragg-Sitton, Shannon M.; Hervol, David S.; Godfroy, Thomas J.

    2009-01-01

    A Direct Drive Gas-Cooled (DDG) reactor core simulator has been coupled to a Brayton Power Conversion Unit (BPCU) for integrated system testing at NASA Glenn Research Center (GRC) in Cleveland, OH. This is a closed-cycle system that incorporates an electrically heated reactor core module, turbo alternator, recuperator, and gas cooler. Nuclear fuel elements in the gas-cooled reactor design are replaced with electric resistance heaters to simulate the heat from nuclear fuel in the corresponding fast spectrum nuclear reactor. The thermodynamic transient behavior of the integrated system was the focus of this test series. In order to better mimic the integrated response of the nuclear-fueled system, a simulated reactivity feedback control loop was implemented. Core power was controlled by a point kinetics model in which the reactivity feedback was based on core temperature measurements; the neutron generation time and the temperature feedback coefficient are provided as model inputs. These dynamic system response tests demonstrate the overall capability of a non-nuclear test facility in assessing system integration issues and characterizing integrated system response times and response characteristics.

  6. Evaluation of the Portable Instantaneous Display Analysis Spectrometer (PIDAS)

    NASA Technical Reports Server (NTRS)

    Lyon, R. J. P.; Rubin, Tod; Ohashi, Makoto

    1988-01-01

    The Portable Instantaneous Display Analysis System (PIDAS) was evaluated by measuring 125 spectra of mineral specimens and rock samples under the following conditions: in the laboratory under artificial illumination and outdoors, on the building patio, while still using the line voltage electric power supplies. The PIDAS was compared and contrasted with the GEOSCAN PFS, Daedalus-Spectrafax 440, and the Geophysical Environmental Research (GER) IRIS Mark 4.

  7. Effects of V2G Reactive Power Compensation on the Component Selection in an EV or PHEV Bidirectional Charger

    SciTech Connect

    Kisacikoglu, Mithat C; Ozpineci, Burak; Tolbert, Leon M

    2010-01-01

    Electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) are becoming a part of the electric grid day by day. Chargers for these vehicles have the ability to make this interaction better for the consumer and for the grid. Vehicle to grid (V2G) power transfer has been under research for more than a decade because of the large energy reserve of an electric vehicle battery and the potential of thousands of these connected to the grid. Rather than discharging the vehicle batteries, reactive power compensation in particular is beneficial for both consumers and for the utility. However, certain adverse effects or requirements of reactive power transfer should be defined before a design stage. To understand the dynamics of this operation, this study investigates the effect of reactive power transfer on the charger system components, especially on the dc-link capacitor and the battery.

  8. Reactive-power compensation of coal mining excavators by using a new-generation STATCOM

    SciTech Connect

    Bilgin, H.F.; Ermis, M.; Kose, K.N.; Cadirci, I.; Acik, A.; Demirci, T.; Terciyanli, A.; Kocak, C.; Yorukoglu, M.

    2007-01-15

    This paper deals with the development and implementation of a current-source-converter-based static synchronous compensator (CSC-STATCOM) applied to the volt-ampere-reactive (VAR) compensation problem of coal mining excavators. It is composed of a +/- 750-kVAR full-bridge CSC with selective harmonic elimination, a low-pass input filter tuned to 200 Hz, and a Delta/Y-connected coupling transformer for connection to medium-voltage load bus. Each power semiconductor switch is composed of an asymmetrical integrated gate commutated thyristor (IGCT) connected in series with a reverse-blocking diode and switched at 500 Hz to eliminate 5th, 7th, 11th, and 13th current harmonics produced by the CSC. Operating principles, power stage, design of dc link, and input filter are also described in this paper. It has been verified by field tests that the developed STATCOM follows rapid fluctuations in nearly symmetrical lagging and leading VAR consumption of electric excavators, resulting in nearly unity power factor on monthly basis, and the harmonic current spectra in the lines of CSC-STATCOM at the point of common coupling comply with the IEEE Standard 519-1992.

  9. New enhanced artificial bee colony (JA-ABC5) algorithm with application for reactive power optimization.

    PubMed

    Sulaiman, Noorazliza; Mohamad-Saleh, Junita; Abro, Abdul Ghani

    2015-01-01

    The standard artificial bee colony (ABC) algorithm involves exploration and exploitation processes which need to be balanced for enhanced performance. This paper proposes a new modified ABC algorithm named JA-ABC5 to enhance convergence speed and improve the ability to reach the global optimum by balancing exploration and exploitation processes. New stages have been proposed at the earlier stages of the algorithm to increase the exploitation process. Besides that, modified mutation equations have also been introduced in the employed and onlooker-bees phases to balance the two processes. The performance of JA-ABC5 has been analyzed on 27 commonly used benchmark functions and tested to optimize the reactive power optimization problem. The performance results have clearly shown that the newly proposed algorithm has outperformed other compared algorithms in terms of convergence speed and global optimum achievement.

  10. Deposition of highly textured AlN thin films by reactive high power impulse magnetron sputtering

    SciTech Connect

    Moreira, Milena A.; Törndahl, Tobias; Katardjiev, Ilia; Kubart, Tomas

    2015-03-15

    Aluminum nitride thin films were deposited by reactive high power impulse magnetron sputtering (HiPIMS) and pulsed direct-current on Si (100) and textured Mo substrates, where the same deposition conditions were used for both techniques. The films were characterized by x-ray diffraction and atomic force microscopy. The results show a pronounced improvement in the AlN crystalline texture for all films deposited by HiPIMS on Si. Already at room temperature, the HiPIMS films exhibited a strong preferred (002) orientation and at 400 °C, no contributions from other orientations were detected. Despite the low film thickness of only 200 nm, an ω-scan full width at half maximum value of 5.1° was achieved on Si. The results are attributed to the high ionization of sputtered material achieved in HiPIMS. On textured Mo, there was no significant difference between the deposition techniques.

  11. Thermal analysis of a reactive generalized Couette flow of power law fluids between concentric cylindrical pipes

    NASA Astrophysics Data System (ADS)

    Makinde, O. D.

    2014-12-01

    In this paper, the steady generalized axial Couette flow of Ostwald-de Waele power law reactive fluids between concentric cylindrical pipes is investigated. It is assumed that the outer cylinder is stationary and exchanges heat with the ambient surrounding following Newton's law of cooling, while the inner cylinder with isothermal surface is set in motion in the axial direction. The model nonlinear differential equations for the momentum and energy balance are obtained and tackled numerically using the shooting method coupled with the Runge-Kutta-Fehlberg integration technique. The effects of various embedded thermophysical parameters on the velocity and temperature fields including skin friction, Nusselt number and thermal criticality conditions are presented graphically and discussed quantitatively.

  12. New Enhanced Artificial Bee Colony (JA-ABC5) Algorithm with Application for Reactive Power Optimization

    PubMed Central

    2015-01-01

    The standard artificial bee colony (ABC) algorithm involves exploration and exploitation processes which need to be balanced for enhanced performance. This paper proposes a new modified ABC algorithm named JA-ABC5 to enhance convergence speed and improve the ability to reach the global optimum by balancing exploration and exploitation processes. New stages have been proposed at the earlier stages of the algorithm to increase the exploitation process. Besides that, modified mutation equations have also been introduced in the employed and onlooker-bees phases to balance the two processes. The performance of JA-ABC5 has been analyzed on 27 commonly used benchmark functions and tested to optimize the reactive power optimization problem. The performance results have clearly shown that the newly proposed algorithm has outperformed other compared algorithms in terms of convergence speed and global optimum achievement. PMID:25879054

  13. Are instantaneous velocities real and really instantaneous?: an argument for the affirmative

    NASA Astrophysics Data System (ADS)

    Smith, Sheldon R.

    Frank Arntzenius has recently suggested that we should reject the standard view that the instantaneous state in classical mechanics consists of both the position and the velocity. In his view, the velocity as ordinarily defined-as the derivative of position with respect to time-cannot be genuinely instantaneous, and, thus, it should be excluded from the instantaneous state. After reviewing Bertrand Russell's traditional objections to the notion of an instantaneous velocity and suggesting that Russell's concerns can be effectively answered, I argue that Arntzenius' attempt to show that the standard definition of velocity fails to yield an instantaneous property is not compelling either. Although I review several suggestions that Arntzenius makes against the existence of instantaneous velocity, much of his case rests upon an intuition, which has also appeared in the work of David Albert, about what is required of genuine instantaneous states. I argue in part that there is no reason to accept this intuition, and, thus, no reason to revise standard physical practice when it comes to the classical, instantaneous state.

  14. Computing Instantaneous Frequency by normalizing Hilbert Transform

    NASA Technical Reports Server (NTRS)

    Huang, Norden E. (Inventor)

    2005-01-01

    This invention presents Normalized Amplitude Hilbert Transform (NAHT) and Normalized Hilbert Transform(NHT), both of which are new methods for computing Instantaneous Frequency. This method is designed specifically to circumvent the limitation set by the Bedorsian and Nuttal Theorems, and to provide a sharp local measure of error when the quadrature and the Hilbert Transform do not agree. Motivation for this method is that straightforward application of the Hilbert Transform followed by taking the derivative of the phase-angle as the Instantaneous Frequency (IF) leads to a common mistake made up to this date. In order to make the Hilbert Transform method work, the data has to obey certain restrictions.

  15. Computing Instantaneous Frequency by normalizing Hilbert Transform

    DOEpatents

    Huang, Norden E.

    2005-05-31

    This invention presents Normalized Amplitude Hilbert Transform (NAHT) and Normalized Hilbert Transform(NHT), both of which are new methods for computing Instantaneous Frequency. This method is designed specifically to circumvent the limitation set by the Bedorsian and Nuttal Theorems, and to provide a sharp local measure of error when the quadrature and the Hilbert Transform do not agree. Motivation for this method is that straightforward application of the Hilbert Transform followed by taking the derivative of the phase-angle as the Instantaneous Frequency (IF) leads to a common mistake made up to this date. In order to make the Hilbert Transform method work, the data has to obey certain restrictions.

  16. Heterodyne laser instantaneous frequency measurement system

    DOEpatents

    Wyeth, Richard W.; Johnson, Michael A.; Globig, Michael A.

    1989-01-01

    A heterodyne laser instantaneous frequency measurement system is disclosed. The system utilizes heterodyning of a pulsed laser beam with a continuous wave laser beam to form a beat signal. The beat signal is processed by a controller or computer which determines both the average frequency of the laser pulse and any changes or chirp of th frequency during the pulse.

  17. Heterodyne laser instantaneous frequency measurement system

    DOEpatents

    Wyeth, Richard W.; Johnson, Michael A.; Globig, Michael A.

    1990-01-01

    A heterodyne laser instantaneous frequency measurement system is disclosed. The system utilizes heterodyning of a pulsed laser beam with a continuous wave laser beam to form a beat signal. The beat signal is processed by a controller or computer which determines both the average frequency of the laser pulse and any changes or chirp of the frequency during the pulse.

  18. Multi-Objective Advanced Inverter Controls to Dispatch the Real and Reactive Power of Many Distributed PV Systems.

    SciTech Connect

    Reno, Matthew J.; Lave, Matthew Samuel; Broderick, Robert Joseph; Seuss, John; Grijalva, Santiago

    2016-01-01

    The research presented in this report compares several real - time control strategies for the power output of a large number of PV distributed throughout a large distribution feeder circuit. Both real and reactive power controls are considered with the goal of minimizing network over - voltage violations caused by large amounts of PV generation. Several control strategies are considered under various assumptions regarding the existence and latency of a communication network. The control parameters are adjusted to maximize the effectiveness of each control. The controls are then compared based on their ability to achieve multiple objectiv es. These objectives include minimizing the total number of voltage violations , minimizing the total amount of PV energy curtailed or reactive power generated, and maximizing the fairness of any control action among all PV systems . The controls are simulat ed on the OpenDSS platform using time series load and spatially - distributed irradiance data.

  19. Process stabilization by peak current regulation in reactive high-power impulse magnetron sputtering of hafnium nitride

    NASA Astrophysics Data System (ADS)

    Shimizu, T.; Villamayor, M.; Lundin, D.; Helmersson, U.

    2016-02-01

    A simple and cost effective approach to stabilize the sputtering process in the transition zone during reactive high-power impulse magnetron sputtering (HiPIMS) is proposed. The method is based on real-time monitoring and control of the discharge current waveforms. To stabilize the process conditions at a given set point, a feedback control system was implemented that automatically regulates the pulse frequency, and thereby the average sputtering power, to maintain a constant maximum discharge current. In the present study, the variation of the pulse current waveforms over a wide range of reactive gas flows and pulse frequencies during a reactive HiPIMS process of Hf-N in an Ar-N2 atmosphere illustrates that the discharge current waveform is a an excellent indicator of the process conditions. Activating the reactive HiPIMS peak current regulation, stable process conditions were maintained when varying the N2 flow from 2.1 to 3.5 sccm by an automatic adjustment of the pulse frequency from 600 Hz to 1150 Hz and consequently an increase of the average power from 110 to 270 W. Hf-N films deposited using peak current regulation exhibited a stable stoichiometry, a nearly constant power-normalized deposition rate, and a polycrystalline cubic phase Hf-N with (1 1 1)-preferred orientation over the entire reactive gas flow range investigated. The physical reasons for the change in the current pulse waveform for different process conditions are discussed in some detail.

  20. An error bound for instantaneous coverage

    NASA Technical Reports Server (NTRS)

    White, Allan L.

    1991-01-01

    An error bound is derived for a reliability model approximation method. The approximation method is appropriate for the semi-Markov models of reconfigurable systems that are designed to achieve extremely high reliability. The semi-Markov models of these system are complex, and a significant amount of their complexity arises from the detailed descriptions of the reconfiguration processes. The reliability model approximation method consists of replacing a detailed description of a reconfiguration process with the probabilities of the possible outcomes of the reconfiguration process. These probabilities are included in the model as instantaneous jumps from the fault-occurrence state. Since little time is spent in the reconfiguration states, instantaneous jumps are a close approximation to the original model. This approximation procedure is shown to produce an overestimation for the probability of system failure, and an error bound is derived for this overestimation.

  1. Instantaneous bit-error-rate meter

    NASA Astrophysics Data System (ADS)

    Slack, Robert A.

    1995-06-01

    An instantaneous bit error rate meter provides an instantaneous, real time reading of bit error rate for digital communications data. Bit error pulses are input into the meter and are first filtered in a buffer stage to provide input impedance matching and desensitization to pulse variations in amplitude, rise time and pulse width. The bit error pulses are transformed into trigger signals for a timing pulse generator. The timing pulse generator generates timing pulses for each transformed bit error pulse, and is calibrated to generate timing pulses having a preselected pulse width corresponding to the baud rate of the communications data. An integrator generates a voltage from the timing pulses that is representative of the bit error rate as a function of the data transmission rate. The integrated voltage is then displayed on a meter to indicate the bit error rate.

  2. Predicting trend reversals using market instantaneous state

    NASA Astrophysics Data System (ADS)

    Bury, Thomas

    2014-06-01

    Collective behaviors taking place in financial markets reveal strongly correlated states especially during a crisis period. A natural hypothesis is that trend reversals are also driven by mutual influences between the different stock exchanges. Using a maximum entropy approach, we find coordinated behavior during trend reversals dominated by the pairwise component. In particular, these events are predicted with high significant accuracy by the ensemble's instantaneous state.

  3. Compatibility of Space Nuclear Power Plant Materials in an Inert He/Xe Working Gas Containing Reactive Impurities

    SciTech Connect

    MM Hall

    2006-01-31

    A major materials selection and qualification issue identified in the Space Materials Plan is the potential for creating materials compatibility problems by combining dissimilar reactor core, Brayton Unit and other power conversion plant materials in a recirculating, inert He/Xe gas loop containing reactive impurity gases. Reported here are results of equilibrium thermochemical analyses that address the compatibility of space nuclear power plant (SNPP) materials in high temperature impure He gas environments. These studies provide early information regarding the constraints that exist for SNPP materials selection and provide guidance for establishing test objectives and environments for SNPP materials qualification testing.

  4. Voltage control for a wind power plant based on the available reactive current of a DFIG and its impacts on the point of interconnection

    SciTech Connect

    Usman, Yasir; Kim, Jinho; Muljadi, Eduard; Kang, Yong Cheol

    2016-01-01

    Wake effects cause wind turbine generators (WTGs) within a wind power plant (WPP) to produce different levels of active power and subsequent reactive power capabilities. Further, the impedance between a WTG and the point of interconnection (POI)-which depends on the distance between them-impacts the WPP's reactive power injection capability at the POI. This paper proposes a voltage control scheme for a WPP based on the available reactive current of the doubly-fed induction generators (DFIGs) and its impacts on the POI to improve the reactive power injection capability of the WPP. In this paper, a design strategy for modifying the gain of DFIG controller is suggested and the comprehensive properties of these control gains are investigated. In the proposed scheme, the WPP controller, which operates in a voltage control mode, sends the command signal to the DFIGs based on the voltage difference at the POI. The DFIG controllers, which operate in a voltage control mode, employ a proportional controller with a limiter. The gain of the proportional controller is adjusted depending on the available reactive current of the DFIG and the series impedance between the DFIG and the POI. The performance of the proposed scheme is validated for various disturbances such as a reactive load connection and grid fault using an EMTP-RV simulator. Furthermore, simulation results demonstrate that the proposed scheme promptly recovers the POI voltage by injecting more reactive power after a disturbance than the conventional scheme.

  5. Voltage control for a wind power plant based on the available reactive current of a DFIG and its impacts on the point of interconnection

    DOE PAGESBeta

    Usman, Yasir; Kim, Jinho; Muljadi, Eduard; Kang, Yong Cheol

    2016-01-01

    Wake effects cause wind turbine generators (WTGs) within a wind power plant (WPP) to produce different levels of active power and subsequent reactive power capabilities. Further, the impedance between a WTG and the point of interconnection (POI)-which depends on the distance between them-impacts the WPP's reactive power injection capability at the POI. This paper proposes a voltage control scheme for a WPP based on the available reactive current of the doubly-fed induction generators (DFIGs) and its impacts on the POI to improve the reactive power injection capability of the WPP. In this paper, a design strategy for modifying the gainmore » of DFIG controller is suggested and the comprehensive properties of these control gains are investigated. In the proposed scheme, the WPP controller, which operates in a voltage control mode, sends the command signal to the DFIGs based on the voltage difference at the POI. The DFIG controllers, which operate in a voltage control mode, employ a proportional controller with a limiter. The gain of the proportional controller is adjusted depending on the available reactive current of the DFIG and the series impedance between the DFIG and the POI. The performance of the proposed scheme is validated for various disturbances such as a reactive load connection and grid fault using an EMTP-RV simulator. Furthermore, simulation results demonstrate that the proposed scheme promptly recovers the POI voltage by injecting more reactive power after a disturbance than the conventional scheme.« less

  6. Observation of a periodic runaway in the reactive Ar/O{sub 2} high power impulse magnetron sputtering discharge

    SciTech Connect

    Shayestehaminzadeh, Seyedmohammad E-mail: shayesteh@mch.rwth-aachen.de; Arnalds, Unnar B.; Magnusson, Rögnvaldur L.; Olafsson, Sveinn

    2015-11-15

    This paper reports the observation of a periodic runaway of plasma to a higher density for the reactive discharge of the target material (Ti) with moderate sputter yield. Variable emission of secondary electrons, for the alternating transition of the target from metal mode to oxide mode, is understood to be the main reason for the runaway occurring periodically. Increasing the pulsing frequency can bring the target back to a metal (or suboxide) mode, and eliminate the periodic transition of the target. Therefore, a pulsing frequency interval is defined for the reactive Ar/O{sub 2} discharge in order to sustain the plasma in a runaway-free mode without exceeding the maximum power that the magnetron can tolerate.

  7. Instantaneous network RTK in Orange County, California

    NASA Astrophysics Data System (ADS)

    Bock, Y.

    2003-04-01

    The Orange County Real Time GPS Network (OCRTN) is an upgrade of a sub-network of SCIGN sites in southern California to low latency (1-2 sec), high-rate (1 Hz) data streaming, analysis, and dissemination. The project is a collaborative effort of the California Spatial Reference Center (CSRC) and the Orange County Public Resource and Facilities Division, with partners from the geophysical community, local and state government, and the private sector. Currently, ten sites are streaming 1 Hz raw data (Ashtech binary MBEN format) by means of dedicated, point-to-point radio modems to a network hub that translates the asynchronous serial data to TCP/IP and onto a PC workstation residing on a local area network. Software residing on the PC allows multiple clients to access the raw data simultaneously though TCP/IP. One of the clients is a Geodetics RTD server that receives and archives (1) the raw 1 Hz network data, (2) estimates of instantaneous positions and zenith tropospheric delays for quality control and detection of ground motion, and (3) RINEX data to decimated to 30 seconds. Data recovery is typically 99-100%. The server also produces 1 Hz RTCM data (messages 18, 19, 3 and 22) that are available by means of TCP/IP to RTK clients with wireless Internet modems. Coverage is excellent throughout the county. The server supports standard RTK users and is compatible with existing GPS instrumentation. Typical latency is 1-2 s, with initialization times of several seconds to minutes OCRTN site spacing is 10-15 km. In addition, the server supports “smart clients” who can retrieve data from the closest n sites (typically 3) and obtain an instantaneous network RTK position with 1-2 s latency. This mode currently requires a PDA running the RTD client software, and a wireless card. Since there is no initialization and re-initialization required this approach is well suited to support high-precision (centimeter-level) dynamic applications such as intelligent transportation

  8. Instantaneous, stepped-frequency, nonlinear radar

    NASA Astrophysics Data System (ADS)

    Ranney, Kenneth; Gallagher, Kyle; Martone, Anthony; Mazzaro, Gregory; Sherbondy, Kelly; Narayanan, Ram

    2015-05-01

    Researchers have recently developed radar systems capable of exploiting non-linear target responses to precisely locate targets in range. These systems typically achieve the bandwidth necessary for range resolution through transmission of either a stepped-frequency or chirped waveform. The second harmonic of the reflected waveform is then analyzed to isolate the non-linear target response. In other experiments, researchers have identified certain targets through the inter-modulation products they produce in response to a multi-tone stimulus. These experiments, however, do not exploit the phase information available in the inter-modulation products. We present a method for exploiting both the magnitude and phase information available in the inter-modulation products to create an "instantaneous" stepped frequency, non-linear target response. The new approach enables us to both maintain the unambiguous range dictated by the fundamental, multi-tone separation and obtain the entire target signature from a single transmitted waveform.

  9. Numerical modelling of instantaneous plate tectonics

    NASA Technical Reports Server (NTRS)

    Minster, J. B.; Haines, E.; Jordan, T. H.; Molnar, P.

    1974-01-01

    Assuming lithospheric plates to be rigid, 68 spreading rates, 62 fracture zones trends, and 106 earthquake slip vectors are systematically inverted to obtain a self-consistent model of instantaneous relative motions for eleven major plates. The inverse problem is linearized and solved iteratively by a maximum-likelihood procedure. Because the uncertainties in the data are small, Gaussian statistics are shown to be adequate. The use of a linear theory permits (1) the calculation of the uncertainties in the various angular velocity vectors caused by uncertainties in the data, and (2) quantitative examination of the distribution of information within the data set. The existence of a self-consistent model satisfying all the data is strong justification of the rigid plate assumption. Slow movement between North and South America is shown to be resolvable.

  10. "Body-In-The-Loop": Optimizing Device Parameters Using Measures of Instantaneous Energetic Cost

    PubMed Central

    Felt, Wyatt; Selinger, Jessica C.; Donelan, J. Maxwell; Remy, C. David

    2015-01-01

    This paper demonstrates methods for the online optimization of assistive robotic devices such as powered prostheses, orthoses and exoskeletons. Our algorithms estimate the value of a physiological objective in real-time (with a body “in-the-loop”) and use this information to identify optimal device parameters. To handle sensor data that are noisy and dynamically delayed, we rely on a combination of dynamic estimation and response surface identification. We evaluated three algorithms (Steady-State Cost Mapping, Instantaneous Cost Mapping, and Instantaneous Cost Gradient Search) with eight healthy human subjects. Steady-State Cost Mapping is an established technique that fits a cubic polynomial to averages of steady-state measures at different parameter settings. The optimal parameter value is determined from the polynomial fit. Using a continuous sweep over a range of parameters and taking into account measurement dynamics, Instantaneous Cost Mapping identifies a cubic polynomial more quickly. Instantaneous Cost Gradient Search uses a similar technique to iteratively approach the optimal parameter value using estimates of the local gradient. To evaluate these methods in a simple and repeatable way, we prescribed step frequency via a metronome and optimized this frequency to minimize metabolic energetic cost. This use of step frequency allows a comparison of our results to established techniques and enables others to replicate our methods. Our results show that all three methods achieve similar accuracy in estimating optimal step frequency. For all methods, the average error between the predicted minima and the subjects’ preferred step frequencies was less than 1% with a standard deviation between 4% and 5%. Using Instantaneous Cost Mapping, we were able to reduce subject walking-time from over an hour to less than 10 minutes. While, for a single parameter, the Instantaneous Cost Gradient Search is not much faster than Steady-State Cost Mapping, the

  11. "Body-In-The-Loop": Optimizing Device Parameters Using Measures of Instantaneous Energetic Cost.

    PubMed

    Felt, Wyatt; Selinger, Jessica C; Donelan, J Maxwell; Remy, C David

    2015-01-01

    This paper demonstrates methods for the online optimization of assistive robotic devices such as powered prostheses, orthoses and exoskeletons. Our algorithms estimate the value of a physiological objective in real-time (with a body "in-the-loop") and use this information to identify optimal device parameters. To handle sensor data that are noisy and dynamically delayed, we rely on a combination of dynamic estimation and response surface identification. We evaluated three algorithms (Steady-State Cost Mapping, Instantaneous Cost Mapping, and Instantaneous Cost Gradient Search) with eight healthy human subjects. Steady-State Cost Mapping is an established technique that fits a cubic polynomial to averages of steady-state measures at different parameter settings. The optimal parameter value is determined from the polynomial fit. Using a continuous sweep over a range of parameters and taking into account measurement dynamics, Instantaneous Cost Mapping identifies a cubic polynomial more quickly. Instantaneous Cost Gradient Search uses a similar technique to iteratively approach the optimal parameter value using estimates of the local gradient. To evaluate these methods in a simple and repeatable way, we prescribed step frequency via a metronome and optimized this frequency to minimize metabolic energetic cost. This use of step frequency allows a comparison of our results to established techniques and enables others to replicate our methods. Our results show that all three methods achieve similar accuracy in estimating optimal step frequency. For all methods, the average error between the predicted minima and the subjects' preferred step frequencies was less than 1% with a standard deviation between 4% and 5%. Using Instantaneous Cost Mapping, we were able to reduce subject walking-time from over an hour to less than 10 minutes. While, for a single parameter, the Instantaneous Cost Gradient Search is not much faster than Steady-State Cost Mapping, the Instantaneous

  12. Silicon oxynitride films deposited by reactive high power impulse magnetron sputtering using nitrous oxide as a single-source precursor

    SciTech Connect

    Hänninen, Tuomas Schmidt, Susann; Jensen, Jens; Hultman, Lars; Högberg, Hans

    2015-09-15

    Silicon oxynitride thin films were synthesized by reactive high power impulse magnetron sputtering of silicon in argon/nitrous oxide plasmas. Nitrous oxide was employed as a single-source precursor supplying oxygen and nitrogen for the film growth. The films were characterized by elastic recoil detection analysis, x-ray photoelectron spectroscopy, x-ray diffraction, x-ray reflectivity, scanning electron microscopy, and spectroscopic ellipsometry. Results show that the films are silicon rich, amorphous, and exhibit a random chemical bonding structure. The optical properties with the refractive index and the extinction coefficient correlate with the film elemental composition, showing decreasing values with increasing film oxygen and nitrogen content. The total percentage of oxygen and nitrogen in the films is controlled by adjusting the gas flow ratio in the deposition processes. Furthermore, it is shown that the film oxygen-to-nitrogen ratio can be tailored by the high power impulse magnetron sputtering-specific parameters pulse frequency and energy per pulse.

  13. Effects of anodic potential and chloride ion on overall reactivity in electrochemical reactors designed for solar-powered wastewater treatment.

    PubMed

    Cho, Kangwoo; Qu, Yan; Kwon, Daejung; Zhang, Hao; Cid, Clément A; Aryanfar, Asghar; Hoffmann, Michael R

    2014-02-18

    We have investigated electrochemical treatment of real domestic wastewater coupled with simultaneous production of molecular H2 as useful byproduct. The electrolysis cells employ multilayer semiconductor anodes with electroactive bismuth-doped TiO2 functionalities and stainless steel cathodes. DC-powered laboratory-scale electrolysis experiments were performed under static anodic potentials (+2.2 or +3.0 V NHE) using domestic wastewater samples, with added chloride ion in variable concentrations. Greater than 95% reductions in chemical oxygen demand (COD) and ammonium ion were achieved within 6 h. In addition, we experimentally determined a decreasing overall reactivity of reactive chlorine species toward COD with an increasing chloride ion concentration under chlorine radicals (Cl·, Cl2(-)·) generation at +3.0 V NHE. The current efficiency for COD removal was 12% with the lowest specific energy consumption of 96 kWh kgCOD(-1) at the cell voltage of near 4 V in 50 mM chloride. The current efficiency and energy efficiency for H2 generation were calculated to range from 34 to 84% and 14 to 26%, respectively. The hydrogen comprised 35 to 60% by volume of evolved gases. The efficacy of our electrolysis cell was further demonstrated by a 20 L prototype reactor totally powered by a photovoltaic (PV) panel, which was shown to eliminate COD and total coliform bacteria in less than 4 h of treatment.

  14. Effects of anodic potential and chloride ion on overall reactivity in electrochemical reactors designed for solar-powered wastewater treatment.

    PubMed

    Cho, Kangwoo; Qu, Yan; Kwon, Daejung; Zhang, Hao; Cid, Clément A; Aryanfar, Asghar; Hoffmann, Michael R

    2014-02-18

    We have investigated electrochemical treatment of real domestic wastewater coupled with simultaneous production of molecular H2 as useful byproduct. The electrolysis cells employ multilayer semiconductor anodes with electroactive bismuth-doped TiO2 functionalities and stainless steel cathodes. DC-powered laboratory-scale electrolysis experiments were performed under static anodic potentials (+2.2 or +3.0 V NHE) using domestic wastewater samples, with added chloride ion in variable concentrations. Greater than 95% reductions in chemical oxygen demand (COD) and ammonium ion were achieved within 6 h. In addition, we experimentally determined a decreasing overall reactivity of reactive chlorine species toward COD with an increasing chloride ion concentration under chlorine radicals (Cl·, Cl2(-)·) generation at +3.0 V NHE. The current efficiency for COD removal was 12% with the lowest specific energy consumption of 96 kWh kgCOD(-1) at the cell voltage of near 4 V in 50 mM chloride. The current efficiency and energy efficiency for H2 generation were calculated to range from 34 to 84% and 14 to 26%, respectively. The hydrogen comprised 35 to 60% by volume of evolved gases. The efficacy of our electrolysis cell was further demonstrated by a 20 L prototype reactor totally powered by a photovoltaic (PV) panel, which was shown to eliminate COD and total coliform bacteria in less than 4 h of treatment. PMID:24417418

  15. K 4R - Knowledge to the Power of RESTful, Resourceful and Reactive Rules

    NASA Astrophysics Data System (ADS)

    Amador, Ricardo

    The Web of today clearly answers questions of the form "What is the representation of ...?". The Semantic Web (SW) of tomorrow aims at answering questions of the form "What is the meaning of ...?". It is our stance that in order to realize the full potential of the original concept proposed by Tim Berners-Lee et al. (in Scientific American, May 2001), the SW must also answer, in a meaningful way, questions of a dynamic and active nature, like "What to do if ...?" or "What to do when ...?". Moreover, SW questions of the form "What to do ...?" must be expressed and answered in a declarative, compositional and language agnostic way. It is our (hypo)thesis that formally established concepts, viz. the Web's REST architectural style, declarative SW representation of resources based on Description Logics (e.g., OWL-DL), and Reactive Rules (e.g., "on Event if Condition do Action" -ECA- rules), provide the proper theoretical foundations to achieve this goal. This paper describes our current research proposal, K 4R (pronounced, with an Italian flavor, "Che fare?"), towards achieving a declarative model for expressing (re)active behavior in and for the SW.

  16. Computation and Experiment: A Powerful Combination to Understand and Predict Reactivities.

    PubMed

    Sperger, Theresa; Sanhueza, Italo A; Schoenebeck, Franziska

    2016-06-21

    Computational chemistry has become an established tool for the study of the origins of chemical phenomena and examination of molecular properties. Because of major advances in theory, hardware and software, calculations of molecular processes can nowadays be done with reasonable accuracy on a time-scale that is competitive or even faster than experiments. This overview will highlight broad applications of computational chemistry in the study of organic and organometallic reactivities, including catalytic (NHC-, Cu-, Pd-, Ni-catalyzed) and noncatalytic examples of relevance to organic synthesis. The selected examples showcase the ability of computational chemistry to rationalize and also predict reactivities of broad significance. A particular emphasis is placed on the synergistic interplay of computations and experiments. It is discussed how this approach allows one to (i) gain greater insight than the isolated techniques, (ii) inspire novel chemistry avenues, and (iii) assist in reaction development. Examples of successful rationalizations of reactivities are discussed, including the elucidation of mechanistic features (radical versus polar) and origins of stereoselectivity in NHC-catalyzed reactions as well as the rationalization of ligand effects on ligation states and selectivity in Pd- and Ni-catalyzed transformations. Beyond explaining, the synergistic interplay of computation and experiments is then discussed, showcasing the identification of the likely catalytically active species as a function of ligand, additive, and solvent in Pd-catalyzed cross-coupling reactions. These may vary between mono- or bisphosphine-bound or even anionic Pd complexes in polar media in the presence of coordinating additives. These fundamental studies also inspired avenues in catalysis via dinuclear Pd(I) cycles. Detailed mechanistic studies supporting the direct reactivity of Pd(I)-Pd(I) with aryl halides as well as applications of air-stable dinuclear Pd(I) catalysts are

  17. SiNx Coatings Deposited by Reactive High Power Impulse Magnetron Sputtering: Process Parameters Influencing the Nitrogen Content.

    PubMed

    Schmidt, Susann; Hänninen, Tuomas; Goyenola, Cecilia; Wissting, Jonas; Jensen, Jens; Hultman, Lars; Goebbels, Nico; Tobler, Markus; Högberg, Hans

    2016-08-10

    Reactive high power impulse magnetron sputtering (rHiPIMS) was used to deposit silicon nitride (SiNx) coatings for biomedical applications. The SiNx growth and plasma characterization were conducted in an industrial coater, using Si targets and N2 as reactive gas. The effects of different N2-to-Ar flow ratios between 0 and 0.3, pulse frequencies, target power settings, and substrate temperatures on the discharge and the N content of SiNx coatings were investigated. Plasma ion mass spectrometry shows high amounts of ionized isotopes during the initial part of the pulse for discharges with low N2-to-Ar flow ratios of <0.16, while signals from ionized molecules rise with the N2-to-Ar flow ratio at the pulse end and during pulse-off times. Langmuir probe measurements show electron temperatures of 2-3 eV for nonreactive discharges and 5.0-6.6 eV for discharges in transition mode. The SiNx coatings were characterized with respect to their composition, chemical bond structure, density, and mechanical properties by X-ray photoelectron spectroscopy, X-ray reflectivity, X-ray diffraction, and nanoindentation, respectively. The SiNx deposition processes and coating properties are mainly influenced by the N2-to-Ar flow ratio and thus by the N content in the SiNx films and to a lower extent by the HiPIMS frequencies and power settings as well as substrate temperatures. Increasing N2-to-Ar flow ratios lead to decreasing growth rates, while the N content, coating densities, residual stresses, and the hardness increase. These experimental findings were corroborated by density functional theory calculations of precursor species present during rHiPIMS.

  18. SiNx Coatings Deposited by Reactive High Power Impulse Magnetron Sputtering: Process Parameters Influencing the Nitrogen Content.

    PubMed

    Schmidt, Susann; Hänninen, Tuomas; Goyenola, Cecilia; Wissting, Jonas; Jensen, Jens; Hultman, Lars; Goebbels, Nico; Tobler, Markus; Högberg, Hans

    2016-08-10

    Reactive high power impulse magnetron sputtering (rHiPIMS) was used to deposit silicon nitride (SiNx) coatings for biomedical applications. The SiNx growth and plasma characterization were conducted in an industrial coater, using Si targets and N2 as reactive gas. The effects of different N2-to-Ar flow ratios between 0 and 0.3, pulse frequencies, target power settings, and substrate temperatures on the discharge and the N content of SiNx coatings were investigated. Plasma ion mass spectrometry shows high amounts of ionized isotopes during the initial part of the pulse for discharges with low N2-to-Ar flow ratios of <0.16, while signals from ionized molecules rise with the N2-to-Ar flow ratio at the pulse end and during pulse-off times. Langmuir probe measurements show electron temperatures of 2-3 eV for nonreactive discharges and 5.0-6.6 eV for discharges in transition mode. The SiNx coatings were characterized with respect to their composition, chemical bond structure, density, and mechanical properties by X-ray photoelectron spectroscopy, X-ray reflectivity, X-ray diffraction, and nanoindentation, respectively. The SiNx deposition processes and coating properties are mainly influenced by the N2-to-Ar flow ratio and thus by the N content in the SiNx films and to a lower extent by the HiPIMS frequencies and power settings as well as substrate temperatures. Increasing N2-to-Ar flow ratios lead to decreasing growth rates, while the N content, coating densities, residual stresses, and the hardness increase. These experimental findings were corroborated by density functional theory calculations of precursor species present during rHiPIMS. PMID:27414283

  19. Instantaneous crack detection using dual PZT transducers

    NASA Astrophysics Data System (ADS)

    Kim, Seung Bum; Sohn, Hoon

    2008-03-01

    A new guided wave based nondestructive testing (NDT) technique is developed to detect crack damage in metallic plates commonly used in aircraft without using prior baseline data or a predetermined decision boundary. In conventional guided wave based techniques, damage is often identified by comparing the "current" data obtained from a potentially damaged condition of a structure with the "past" baseline data collected at the pristine condition of the structure. However, it has been reported that this type of pattern comparison with the baseline data can lead to increased false alarms due to its susceptibility to varying operational and environmental conditions of the structure. In order to tackle this issue, a reference-free damage detection technique is previously developed using two pairs of collocated lead zirconate titanate transducers (PZTs) placed on both sides of a plate. In this study, this reference-free technique is further advanced so that the PZT transducers can be placed only on one side of the specimen. Crack formation creates Lamb wave mode conversion due to a sudden change in the thickness of the structure. Then, the proposed technique instantly detects the appearance of the crack by extracting this mode conversion from the measured Lamb waves. This study suggests a reference-free statistical approach that enables damage classification using only the current data set. Numerical and experimental results are presented to demonstrate the applicability of the proposed technique to instantaneous crack detection.

  20. Observing and recording instantaneous images on ATM television monitors

    NASA Technical Reports Server (NTRS)

    Patterson, N. P.; Delamere, W. A.; Tousey, R.

    1977-01-01

    A persistent image-converter device was utilized to make visible to the astronaut solar images that were isolated, instantaneous flashes on the ATM TV monitors. In addition, these instantaneous images, as well as normal TV images, were recorded with a Polaroid SX-70 camera for study by the astronauts.

  1. Instantaneous frequency based newborn EEG seizure characterisation

    NASA Astrophysics Data System (ADS)

    Mesbah, Mostefa; O'Toole, John M.; Colditz, Paul B.; Boashash, Boualem

    2012-12-01

    The electroencephalogram (EEG), used to noninvasively monitor brain activity, remains the most reliable tool in the diagnosis of neonatal seizures. Due to their nonstationary and multi-component nature, newborn EEG seizures are better represented in the joint time-frequency domain than in either the time domain or the frequency domain. Characterising newborn EEG seizure nonstationarities helps to better understand their time-varying nature and, therefore, allow developing efficient signal processing methods for both modelling and seizure detection and classification. In this article, we used the instantaneous frequency (IF) extracted from a time-frequency distribution to characterise newborn EEG seizures. We fitted four frequency modulated (FM) models to the extracted IFs, namely a linear FM, a piecewise-linear FM, a sinusoidal FM, and a hyperbolic FM. Using a database of 30-s EEG seizure epochs acquired from 35 newborns, we were able to show that, depending on EEG channel, the sinusoidal and piecewise-linear FM models best fitted 80-98% of seizure epochs. To further characterise the EEG seizures, we calculated the mean frequency and frequency span of the extracted IFs. We showed that in the majority of the cases (>95%), the mean frequency resides in the 0.6-3 Hz band with a frequency span of 0.2-1 Hz. In terms of the frequency of occurrence of the four seizure models, the statistical analysis showed that there is no significant difference( p = 0.332) between the two hemispheres. The results also indicate that there is no significant differences between the two hemispheres in terms of the mean frequency ( p = 0.186) and the frequency span ( p = 0.302).

  2. The state of the art of the development of SMES for bridging instantaneous voltage dips in Japan

    NASA Astrophysics Data System (ADS)

    Nagaya, Shigeo; Hirano, Naoki; Katagiri, Toshio; Tamada, Tsutomu; Shikimachi, Koji; Iwatani, Yu; Saito, Fusao; Ishii, Yusuke

    2012-12-01

    Development of apparatuses for protecting industrial facilities such as semiconductor plants or information industries from instantaneous voltage dips, which requires very large output power, has been expected. A Superconducting magnetic energy storage system (SMES), one of such apparatus, consists of superconducting magnets that must withstand high voltage during operation and require high reliability. We have already development of SMES using conventional superconducting coils and done the field test of the SMES for bridging instantaneous voltage dips. After field test, the commercial SMES for instantaneous voltage dips is working there. Since field test has started, we have confirmed nearly 40 operations, and all have succeeded. In 2011, three commercial SMES units for bridging instantaneous voltage dips are operating in Japan.

  3. Reactive Inkjet Printing of Biocompatible Enzyme Powered Silk Micro-Rockets.

    PubMed

    Gregory, David A; Zhang, Yu; Smith, Patrick J; Zhao, Xiubo; Ebbens, Stephen J

    2016-08-01

    Inkjet-printed enzyme-powered silk-based micro-rockets are able to undergo autonomous motion in a vast variety of fluidic environments including complex media such as human serum. By means of digital inkjet printing it is possible to alter the catalyst distribution simply and generate varying trajectory behavior of these micro-rockets. Made of silk scaffolds containing enzymes these micro-rockets are highly biocompatible and non-biofouling. PMID:27345008

  4. Engineering model of the electric drives of separation device for simulation of automatic control systems of reactive power compensation by means of serially connected capacitors

    NASA Astrophysics Data System (ADS)

    Juromskiy, V. M.

    2016-09-01

    It is developed a mathematical model for an electric drive of high-speed separation device in terms of the modeling dynamic systems Simulink, MATLAB. The model is focused on the study of the automatic control systems of the power factor (Cosφ) of an actuator by compensating the reactive component of the total power by switching a capacitor bank in series with the actuator. The model is based on the methodology of the structural modeling of dynamic processes.

  5. Measurement of ultrashort pulses with a non-instantaneous nonlinearity

    SciTech Connect

    DeLong, K.W.; Ladera, C.L.; Trebino, R.; Kohler, B.; Wilson, K.R.

    1995-02-01

    We show how non-instantaneous nonlinearities can be used to characterize an ultrashort pulse in an extension of the Frequency-Resolved Optical Gating technique. We demonstrate this principle using the Raman effect in fused silica.

  6. Estimating instantaneous energetic cost during non-steady-state gait.

    PubMed

    Selinger, Jessica C; Donelan, J Maxwell

    2014-12-01

    Respiratory measures of oxygen and carbon dioxide are routinely used to estimate the body's steady-state metabolic energy use. However, slow mitochondrial dynamics, long transit times, complex respiratory control mechanisms, and high breath-by-breath variability obscure the relationship between the body's instantaneous energy demands (instantaneous energetic cost) and that measured from respiratory gases (measured energetic cost). The purpose of this study was to expand on traditional methods of assessing metabolic cost by estimating instantaneous energetic cost during non-steady-state conditions. To accomplish this goal, we first imposed known changes in energy use (input), while measuring the breath-by-breath response (output). We used these input/output relationships to model the body as a dynamic system that maps instantaneous to measured energetic cost. We found that a first-order linear differential equation well approximates transient energetic cost responses during gait. Across all subjects, model fits were parameterized by an average time constant (τ) of 42 ± 12 s with an average R(2) of 0.94 ± 0.05 (mean ± SD). Armed with this input/output model, we next tested whether we could use it to reliably estimate instantaneous energetic cost from breath-by-breath measures under conditions that simulated dynamically changing gait. A comparison of the imposed energetic cost profiles and our estimated instantaneous cost demonstrated a close correspondence, supporting the use of our methodology to study the role of energetics during locomotor adaptation and learning.

  7. Dynamic activation of Src induced by low-power laser irradiation in living cells mediated by reactive oxygen species

    NASA Astrophysics Data System (ADS)

    Zhang, Juntao; Gao, Xuejuan; Xing, Da; Liu, Lei

    2007-11-01

    Low-power laser irradiation (LPLI) leads to photochemical reaction and then activates intracellular several signaling pathway. Reactive oxygen species (ROS) are considered to be the primary messengers produced by LPLI. Here, we studied the signaling pathway mediated by ROS upon the stimulation of LPLI. Src tyrosine kinases are well-known targets of ROS and can be activated by oxidative events. Using a Src reporter based on fluorescence resonance energy transfer (FRET) technique, we visualized the dynamic Src activation in Hela cells immediately after LPLI. Moreover, Src activity was enhanced by increasing the duration of LPLI. In addition, our results suggested that ROS were key mediators of Src activation, as ROS scavenger, vitamin C decreased and exogenous H IIO II increased the activity of Src. Meanwhile, Gö6983 loading did not block the effect of LPLI. CCK-8 experiments proved that cell vitality was prominently improved by LPLI with all the doses we applied in our experiments ranging from 3 to 25J/cm2. The results indicated that LPLI/ROS/Src pathway may be involved in the LPLI biostimulation effects.

  8. Development of geomorphologic instantaneous unit hydrograph for a large watershed.

    PubMed

    Ghumman, Abdul Razzaq; Ahmad, Muhammad Masood; Hashmi, Hashim Nisar; Kamal, Mumtaz Ahmad

    2012-05-01

    Hill torrents cause a lot of environmental and property damage in Pakistan every year. Proper assessment of direct runoff in the form of hill torrents is essential for protection of environment, property, and human life. In this paper, direct surface runoff hydrograph (DSRH) was derived for a large catchment using the geomorphologic instantaneous unit hydrograph concept. The catchment with hill torrent flows in semi-arid region of Pakistan was selected for this study. It was divided into series of linear cascades and hydrologic parameters required for Nash's conceptual model, and were estimated using geomorphology of the basin. Geomorphologic parameters were derived from satellite images of the basin and ERDAS and ArcGIS were used for data processing. Computer program was developed to systematically estimate the dynamic velocity, its related parameters by optimization and thereby to simulate the DSRH. The data regarding rainfall-runoff and satellite images were collected from Punjab Irrigation and Power Department, Pakistan. Model calibration and validation was made for 15 rainfall-runoff events. Ten events were used for calibration and five for validation. Model efficiency was found to be more than 90% and root mean square error to be about 5%. Impact of variation in model parameters (shape parameter and storage coefficient) on DSRH was investigated. For shape parameter, the number of linear cascades varied from 1 to 3 and it was found that the shaper parameter value of 3 produced the best DSRH. Various values of storage coefficient were used and it was observed that the value determined from geomorphology and the dynamic velocity produced the best results.

  9. Development of geomorphologic instantaneous unit hydrograph for a large watershed.

    PubMed

    Ghumman, Abdul Razzaq; Ahmad, Muhammad Masood; Hashmi, Hashim Nisar; Kamal, Mumtaz Ahmad

    2012-05-01

    Hill torrents cause a lot of environmental and property damage in Pakistan every year. Proper assessment of direct runoff in the form of hill torrents is essential for protection of environment, property, and human life. In this paper, direct surface runoff hydrograph (DSRH) was derived for a large catchment using the geomorphologic instantaneous unit hydrograph concept. The catchment with hill torrent flows in semi-arid region of Pakistan was selected for this study. It was divided into series of linear cascades and hydrologic parameters required for Nash's conceptual model, and were estimated using geomorphology of the basin. Geomorphologic parameters were derived from satellite images of the basin and ERDAS and ArcGIS were used for data processing. Computer program was developed to systematically estimate the dynamic velocity, its related parameters by optimization and thereby to simulate the DSRH. The data regarding rainfall-runoff and satellite images were collected from Punjab Irrigation and Power Department, Pakistan. Model calibration and validation was made for 15 rainfall-runoff events. Ten events were used for calibration and five for validation. Model efficiency was found to be more than 90% and root mean square error to be about 5%. Impact of variation in model parameters (shape parameter and storage coefficient) on DSRH was investigated. For shape parameter, the number of linear cascades varied from 1 to 3 and it was found that the shaper parameter value of 3 produced the best DSRH. Various values of storage coefficient were used and it was observed that the value determined from geomorphology and the dynamic velocity produced the best results. PMID:21713477

  10. An instantaneous normal mode description of relaxation in supercooled liquids

    NASA Astrophysics Data System (ADS)

    Keyes, T.; Vijayadamodar, G. V.; Zurcher, U.

    1997-03-01

    Relaxation in supercooled liquids is formulated from the instantaneous normal modes (INM) point of view. The frequency and temperature dependence of the unstable, imaginary frequency lobe of the INM density of states, <ρu(ω,T)> (for simplicity we write ω instead of iω), is investigated and characterized over a broad temperature range, 10⩾T⩾0.42, in the unit density Lennard-Jones liquid. INM theories of diffusion invoke Im-ω modes descriptive of barrier crossing, but not all imaginary frequency modes fall into this category. There exists a cutoff frequency ωc such that modes with ω<ωc correspond to "shoulder potentials," whereas the potential profiles include barrier-crossing double wells for ω>ωc. Given that only modes with ω>ωc contribute to diffusion, the barrier crossing rate, ωh, and the self diffusion constant D, are shown to be proportional to the density of states evaluated at the cutoff frequency, <ρu(ωc,T)>. The density of states exhibits crossover behavior in its temperature dependence such that the exponential T-dependence of D(T) crosses over from Zwanzig-Bassler exp(-E2/T2) behavior at low T to Arrhenius exp(-E/T) behavior at high T; the exponential may be too weak to be observed, in which case D(T) is a power law. Based on the properties of LJ, a general INM description of strong and fragile liquids is presented, with a physical interpretation in terms of the "landscape" of the potential energy surface.

  11. An arbitrarily short reply to Sheldon Smith on instantaneous velocities

    NASA Astrophysics Data System (ADS)

    Arntzenius, Frank

    The main issue is the question whether the standard calculus definition of velocities allows velocities to be part of the instantaneous states of objects. According to David Albert and I this is implausible, for if they were, then the instantaneous state of an object at a time t would in virtue of logic and definition alone impose a severe constraint on the history of instantaneous states of that object at other times. One can picture the constraint as follows: represent the position at time t by a dot on a piece of paper; represent the velocity at time t by an arrow that points away from that dot. The positions around time t can then be represented as a (parameterized) curve. The constraint now is that the curve must have the arrow as its tangent: as one gets close to t the curve must become parallel to the arrow (and must be parameterized at a rate that corresponds to the length of the arrow). This rules out many possible histories at times other than t. But surely an instantaneous state at time t ought not by logic and definition alone to constrain histories of instantaneous states at other times. Laws of nature and contingent relations can imply such constraints, but logic and definition should not. Compare: the intrinsic state at some spatial location x ought not by logic and definition alone to constrain the intrinsic states at other spatial locations. (For Lewis (1986) this is virtually a definition of "intrinsic".)

  12. Instantaneous Normal Modes and the Protein Glass Transition

    PubMed Central

    Schulz, Roland; Krishnan, Marimuthu; Daidone, Isabella; Smith, Jeremy C.

    2009-01-01

    Abstract In the instantaneous normal mode method, normal mode analysis is performed at instantaneous configurations of a condensed-phase system, leading to modes with negative eigenvalues. These negative modes provide a means of characterizing local anharmonicities of the potential energy surface. Here, we apply instantaneous normal mode to analyze temperature-dependent diffusive dynamics in molecular dynamics simulations of a small protein (a scorpion toxin). Those characteristics of the negative modes are determined that correlate with the dynamical (or glass) transition behavior of the protein, as manifested as an increase in the gradient with T of the average atomic mean-square displacement at ∼220 K. The number of negative eigenvalues shows no transition with temperature. Further, although filtering the negative modes to retain only those with eigenvectors corresponding to double-well potentials does reveal a transition in the hydration water, again, no transition in the protein is seen. However, additional filtering of the protein double-well modes, so as to retain only those that, on energy minimization, escape to different regions of configurational space, finally leads to clear protein dynamical transition behavior. Partial minimization of instantaneous configurations is also found to remove nondiffusive imaginary modes. In summary, examination of the form of negative instantaneous normal modes is shown to furnish a physical picture of local diffusive dynamics accompanying the protein glass transition. PMID:19167298

  13. Instantaneous Normal Modes and the Protein Glass Transition

    SciTech Connect

    Schultz, Roland; Krishnan, Marimuthu; Daidone, Isabella; Smith, Jeremy C

    2009-01-01

    In the instantaneous normal mode method, normal mode analysis is performed at instantaneous configurations of a condensed-phase system, leading to modes with negative eigenvalues. These negative modes provide a means of characterizing local anharmonicities of the potential energy surface. Here, we apply instantaneous normal mode to analyze temperature-dependent diffusive dynamics in molecular dynamics simulations of a small protein (a scorpion toxin). Those characteristics of the negative modes are determined that correlate with the dynamical (or glass) transition behavior of the protein, as manifested as an increase in the gradient with T of the average atomic mean-square displacement at 220 K. The number of negative eigenvalues shows no transition with temperature. Further, although filtering the negative modes to retain only those with eigenvectors corresponding to double-well potentials does reveal a transition in the hydration water, again, no transition in the protein is seen. However, additional filtering of the protein double-well modes, so as to retain only those that, on energy minimization, escape to different regions of configurational space, finally leads to clear protein dynamical transition behavior. Partial minimization of instantaneous configurations is also found to remove nondiffusive imaginary modes. In summary, examination of the form of negative instantaneous normal modes is shown to furnish a physical picture of local diffusive dynamics accompanying the protein glass transition.

  14. Diffusion of an instantaneous cluster of particles in homogeneous turbulence

    NASA Astrophysics Data System (ADS)

    Kaplan, H.; Dinar, N.

    In this work we study the diffusion of instantaneous puffs vs the diffusion of continuous plumes. The model which we use is a Lagrangian model for the motion of N particles suggested by Kaplan and Dinar (1988, J. compt. Phys. 79, 317-335). This model is based on the approach of Richardson to the relative diffusion which states that the instantaneous relative velocity of particles is a function of their instantaneous separation. Results show that the diffusion of a puff is slower than that of a continuous source. We find that the puff evolves more slowly than in the analytic model of Lee and Stone (1983, Atmospheric Environment17, 2477-2481), since in their model diffusion is influenced only by the initial conditions. The effect of the source size on the diffusion rate is studied as well.

  15. Popescu-Rohrlich correlations imply efficient instantaneous nonlocal quantum computation

    NASA Astrophysics Data System (ADS)

    Broadbent, Anne

    2016-08-01

    In instantaneous nonlocal quantum computation, two parties cooperate in order to perform a quantum computation on their joint inputs, while being restricted to a single round of simultaneous communication. Previous results showed that instantaneous nonlocal quantum computation is possible, at the cost of an exponential amount of prior shared entanglement (in the size of the input). Here, we show that a linear amount of entanglement suffices, (in the size of the computation), as long as the parties share nonlocal correlations as given by the Popescu-Rohrlich box. This means that communication is not required for efficient instantaneous nonlocal quantum computation. Exploiting the well-known relation to position-based cryptography, our result also implies the impossibility of secure position-based cryptography against adversaries with nonsignaling correlations. Furthermore, our construction establishes a quantum analog of the classical communication complexity collapse under nonsignaling correlations.

  16. The effect of slip heterogeneity and non-instantaneous rupture in numerical modelling of an Iberian seismogenic tsunami

    NASA Astrophysics Data System (ADS)

    Williams, David; Piggott, Matthew; Hill, Jon; Avdis, Alexandros; Collins, Gareth; Kramer, Stephan

    2015-04-01

    In many studies of historical seismogenic tsunamis, such as the Lisbon 1755 event, rupture is modelled as being homogeneous and instantaneous. Here a method is proposed to estimate slip as an asymmetric sinusoid, rather than as an average slip, using empirical scaling laws, observations of slip on faults, and by conserving seismic moment. Rupture propagation is modelled using simple physical assumptions of rupture velocity, slip velocity and hypocentre location. Tsunami simulations are then conducted using the open source finite element Fluidity software, with an unstructured and multiscale computational mesh. For non-instantaneous rupture, a time-dependent normal flow velocity boundary condition is imposed within the tsunamigenic region, and for instantaneous rupture vertical sea floor deformation is translated to the sea surface. This study shows that the range of maximum wave heights for different heterogeneous slips is strongly negatively correlated to distance from coastline to earthquake epicentre according to a power law. It is difficult to predict the maximum wave height at local coastlines when slip heterogeneity is taken into account, and therefore a wide range of slip distributions when modelling is recommended. However, modelling rupture non-instantaneously suggests that maximum wave heights at local coastlines may be consistently under-estimated by 5-10% compared to when modelled instantaneously. The UK coastline is shown to be protected from an Iberian tsunami for all models used in this study.

  17. Tracking instantaneous entropy in heartbeat dynamics through inhomogeneous point-process nonlinear models.

    PubMed

    Valenza, Gaetano; Citi, Luca; Scilingo, Enzo Pasquale; Barbieri, Riccardo

    2014-01-01

    Measures of entropy have been proved as powerful quantifiers of complex nonlinear systems, particularly when applied to stochastic series of heartbeat dynamics. Despite the remarkable achievements obtained through standard definitions of approximate and sample entropy, a time-varying definition of entropy characterizing the physiological dynamics at each moment in time is still missing. To this extent, we propose two novel measures of entropy based on the inho-mogeneous point-process theory. The RR interval series is modeled through probability density functions (pdfs) which characterize and predict the time until the next event occurs as a function of the past history. Laguerre expansions of the Wiener-Volterra autoregressive terms account for the long-term nonlinear information. As the proposed measures of entropy are instantaneously defined through such probability functions, the proposed indices are able to provide instantaneous tracking of autonomic nervous system complexity. Of note, the distance between the time-varying phase-space vectors is calculated through the Kolmogorov-Smirnov distance of two pdfs. Experimental results, obtained from the analysis of RR interval series extracted from ten healthy subjects during stand-up tasks, suggest that the proposed entropy indices provide instantaneous tracking of the heartbeat complexity, also allowing for the definition of complexity variability indices.

  18. Tracking instantaneous entropy in heartbeat dynamics through inhomogeneous point-process nonlinear models.

    PubMed

    Valenza, Gaetano; Citi, Luca; Scilingo, Enzo Pasquale; Barbieri, Riccardo

    2014-01-01

    Measures of entropy have been proved as powerful quantifiers of complex nonlinear systems, particularly when applied to stochastic series of heartbeat dynamics. Despite the remarkable achievements obtained through standard definitions of approximate and sample entropy, a time-varying definition of entropy characterizing the physiological dynamics at each moment in time is still missing. To this extent, we propose two novel measures of entropy based on the inho-mogeneous point-process theory. The RR interval series is modeled through probability density functions (pdfs) which characterize and predict the time until the next event occurs as a function of the past history. Laguerre expansions of the Wiener-Volterra autoregressive terms account for the long-term nonlinear information. As the proposed measures of entropy are instantaneously defined through such probability functions, the proposed indices are able to provide instantaneous tracking of autonomic nervous system complexity. Of note, the distance between the time-varying phase-space vectors is calculated through the Kolmogorov-Smirnov distance of two pdfs. Experimental results, obtained from the analysis of RR interval series extracted from ten healthy subjects during stand-up tasks, suggest that the proposed entropy indices provide instantaneous tracking of the heartbeat complexity, also allowing for the definition of complexity variability indices. PMID:25571453

  19. Determination of the relative power density distribution in a heterogeneous reactor from the results of measurements of the reactivity effects and the neutron importance function

    NASA Astrophysics Data System (ADS)

    Bobrov, A. A.; Glushkov, E. S.; Zimin, A. A.; Kapitonova, A. V.; Kompaniets, G. V.; Nosov, V. I.; Petrushenko, R. P.; Smirnov, O. N.

    2012-12-01

    A method for experimental determination of the relative power density distribution in a heterogeneous reactor based on measurements of fuel reactivity effects and importance of neutrons from a californium source is proposed. The method was perfected on two critical assembly configurations at the NARCISS facility of the Kurchatov Institute, which simulated a small-size heterogeneous nuclear reactor. The neutron importance measurements were performed on subcritical and critical assemblies. It is shown that, along with traditionally used activation methods, the developed method can be applied to experimental studies of special features of the power density distribution in critical assemblies and reactors.

  20. Determination of the relative power density distribution in a heterogeneous reactor from the results of measurements of the reactivity effects and the neutron importance function

    SciTech Connect

    Bobrov, A. A.; Glushkov, E. S.; Zimin, A. A.; Kapitonova, A. V.; Kompaniets, G. V.; Nosov, V. I. Petrushenko, R. P.; Smirnov, O. N.

    2012-12-15

    A method for experimental determination of the relative power density distribution in a heterogeneous reactor based on measurements of fuel reactivity effects and importance of neutrons from a californium source is proposed. The method was perfected on two critical assembly configurations at the NARCISS facility of the Kurchatov Institute, which simulated a small-size heterogeneous nuclear reactor. The neutron importance measurements were performed on subcritical and critical assemblies. It is shown that, along with traditionally used activation methods, the developed method can be applied to experimental studies of special features of the power density distribution in critical assemblies and reactors.

  1. Instantaneous Observability of Tightly Coupled SINS/GPS during Maneuvers.

    PubMed

    Jiang, Junxiang; Yu, Fei; Lan, Haiyu; Dong, Qianhui

    2016-01-01

    The tightly coupled strapdown inertial navigation system (SINS)/global position system (GPS) has been widely used. The system observability determines whether the system state can be estimated by a filter efficiently or not. In this paper, the observability analysis of a two-channel and a three-channel tightly coupled SINS/GPS are performed, respectively, during arbitrary translational maneuvers and angle maneuvers, where the translational maneuver and angle maneuver are modeled. A novel instantaneous observability matrix (IOM) based on a reconstructed psi-angle model is proposed to make the theoretical analysis simpler, which starts from the observability definition directly. Based on the IOM, a series of theoretical analysis are performed. Analysis results show that almost all kinds of translational maneuver and angle maneuver can make a three-channel system instantaneously observable, but there is no one translational maneuver or angle maneuver can make a two-channel system instantaneously observable. The system's performance is investigated when the system is not instantaneously observable. A series of simulation studies based on EKF are performed to confirm the analytic conclusions. PMID:27240369

  2. Digital speech interpolation with nearly instantaneous companding or ADPCM

    NASA Astrophysics Data System (ADS)

    Suyderhoud, H. G.; Onufry, M.; Yatsuzuka, Y.; Virupaksha, K.

    Efficient encoding algorithms are becoming increasingly attractive for satellite transmission as their performance is improved. Two techniques, nearly instantaneous companding (NIC) and adaptive differential pulse code modulation (ADPCM), will be described for use in a digital speech interpolation application. The unique features of both are highlighted, particularly with respect to the capability of withstanding overload and accommodating VF data transmission.

  3. Estimation of instantaneous venous blood saturation using the photoplethysmograph waveform.

    PubMed

    Shafqat, K; Langford, R M; Kyriacou, P A

    2015-10-01

    Non-invasive estimation of regional venous saturation (SxvO2) using a conventional pulse oximeter could provide a means of obtaining clinically relevant information. This study was carried out in order to investigate the hypothesis that SxvO2 could be estimated by utilising the modulations created by positive pressure ventilation in the photoplethysmograph (PPG) signals. The modulations caused by the mechanical ventilator were extracted from oesophageal PPG signals obtained from 12 patients undergoing cardiothoracic surgery. The signals analysed in this work were acquired in a previous study. For the purpose of this analysis the raw PPG signal was considered to have three major components, ac PPG signal (cardiac related component), a static component or dc PPG signal (created mostly by the absorption of light by surrounding tissue) and the ventilator modulation component. These components were then used to estimate instantaneous arterial blood oxygen saturation (SpO2) and SxvO2 by utilising time-frequency analysis technique of smoothed-pseudo Wigner-Ville distribution (SPWVD). The results showed that there was no significant difference in the traditionally-derived (time-domain) arterial saturation and the instantaneous arterial saturation. However, the instantaneous venous saturation was found to be significantly lower than the estimated time-domain and instantaneous arterial saturation (P   =  < 0.001, n = 12). PMID:26365652

  4. Instantaneous Observability of Tightly Coupled SINS/GPS during Maneuvers

    PubMed Central

    Jiang, Junxiang; Yu, Fei; Lan, Haiyu; Dong, Qianhui

    2016-01-01

    The tightly coupled strapdown inertial navigation system (SINS)/global position system (GPS) has been widely used. The system observability determines whether the system state can be estimated by a filter efficiently or not. In this paper, the observability analysis of a two-channel and a three-channel tightly coupled SINS/GPS are performed, respectively, during arbitrary translational maneuvers and angle maneuvers, where the translational maneuver and angle maneuver are modeled. A novel instantaneous observability matrix (IOM) based on a reconstructed psi-angle model is proposed to make the theoretical analysis simpler, which starts from the observability definition directly. Based on the IOM, a series of theoretical analysis are performed. Analysis results show that almost all kinds of translational maneuver and angle maneuver can make a three-channel system instantaneously observable, but there is no one translational maneuver or angle maneuver can make a two-channel system instantaneously observable. The system’s performance is investigated when the system is not instantaneously observable. A series of simulation studies based on EKF are performed to confirm the analytic conclusions. PMID:27240369

  5. Instantaneous Spreading Versus Space Localization for Nonrelativistic Quantum Systems

    NASA Astrophysics Data System (ADS)

    Coutinho, F. A. B.; Wreszinski, W. F.

    2016-08-01

    A theorem of Hegerfeldt (Kielanowski et al. 1998) establishes, for a class of quantum systems, a dichotomy between those which are permanently localized in a bounded region of space, and those exhibiting instantaneous spreading. We analyze in some detail the physical inconsistencies which follow from both of these options, and formulate which, in our view, are the basic open problems.

  6. Calculation and comparison of xenon and samarium reactivities of the HEU, LEU core in the low power research reactor.

    PubMed

    Dawahra, S; Khattab, K; Saba, G

    2015-07-01

    Comparative studies for the conversion of the fuel from HEU to LEU in the Miniature Neutron Source Reactor (MNSR) have been performed using the MCNP4C and GETERA codes. The precise calculations of (135)Xe and (149)Sm concentrations and reactivities were carried out and compared during the MNSR operation time and after shutdown for the existing HEU fuel (UAl4-Al, 90% enriched) and the potential LEU fuels (U3Si2-Al, U3Si-Al, U9Mo-Al, 19.75% enriched and UO2, 12.6% enriched) in this paper using the MCNP4C and GETERA codes. It was found that the (135)Xe and (149)Sm reactivities did not reach their equilibrium reactivities during the daily operating time of the reactor. The (149)Sm reactivities could be neglected compared to (135)Xe reactivities during the reactor operating time and after shutdown. The calculations for the UAl4-Al produced the highest (135)Xe reactivity in all the studied fuel group during the reactor operation (0.39 mk) and after the reactor shutdown (0.735 mk), It followed by U3Si-Al (0.34 mk, 0.653 mk), U3Si2-Al (0.33 mk, 0.634 mk), U9Mo-Al (0.3 mk, 0.568 mk) and UO2 (0.24 mk, 0.448 mk) fuels, respectively. Finally, the results showed that the UO2 was the best candidate for fuel conversion to LEU in the MNSR since it gave the lowest (135)Xe reactivity during the reactor operation and after shutdown.

  7. Exhaust pressure pulsation observation from turbocharger instantaneous speed measurement

    NASA Astrophysics Data System (ADS)

    Macián, V.; Luján, J. M.; Bermúdez, V.; Guardiola, C.

    2004-06-01

    In internal combustion engines, instantaneous exhaust pressure measurements are difficult to perform in a production environment. The high temperature of the exhaust manifold and its pulsating character make its application to exhaust gas recirculation control algorithms impossible. In this paper an alternative method for estimating the exhaust pressure pulsation is presented. A numerical model is built which enables the exhaust pressure pulses to be predicted from instantaneous turbocharger speed measurements. Although the model is data based, a theoretical description of the process is also provided. This combined approach makes it possible to export the model for different engine operating points. Also, compressor contribution in the turbocharger speed pulsation is discussed extensively. The compressor contribution is initially neglected, and effects of this simplified approach are analysed.

  8. Instantaneous Wavelet Energetic Transfers between Atmospheric Blocking and Local Eddies.

    NASA Astrophysics Data System (ADS)

    Fournier, Aimé

    2005-07-01

    A new wavelet energetics technique, based on best-shift orthonormal wavelet analysis (OWA) of an instantaneous synoptic map, is constructed for diagnosing nonlinear kinetic energy (KE) transfers in five observed blocking cases. At least 90% of the longitudinal variance of time and latitude band mean 50-kPa geopotential is reconstructed by only two wavelets using best shift. This superior efficiency to the standard OWAs persists for time-evolving structures. The cases comprise two categories, respectively dominated by zonal-wavenumber sets {1} and {1, 2}. Further OWA of instantaneous residual nonblocking structures, combined with new “nearness” criteria, yields three more orthogonal components, representing smaller-scale eddies near the block (upstream and downstream) and distant structures. This decomposition fulfills a vision expressed to the author by Saltzman. Such a decomposition is not obtainable by simple Fourier analysis.Eddy patterns apparent in the components' contours suggest inferring geostrophic energetic interactions, but the component Rossby numbers may be too large to support the inference. However, a new result enabled by this method is the instantaneous attribution of blocking strain-field effects to particular energetically interactive eddies, consistent with Shutts' hypothesis. Such attribution was only possible before in simplified models or in a time-average sense. In four of five blocks, the upstream eddies feed KE to the block, which in turn, in three of four cases, transmits KE to the downstream eddies. The small case size precludes statistically significant conclusions. The appendixes link low-order blocking structure and dynamics to some wavelet design principles and propose a new interaction diagnosis, similar to E-vector analysis, but instantaneous.

  9. Analog computer implementation of four instantaneous distortion indices

    NASA Technical Reports Server (NTRS)

    Costakis, W. G.

    1974-01-01

    Dynamic distortion data obtained from inlet engine compatibility test on a J85-GE-13 engine are used to establish the feasibility of using on-line generated indices as control signals. These data are analyzed over time increments of 1.3 seconds on an analog computer. The analog program of four instantaneous distortion indices and their results are presented. A modified approach in determining the extent of distortion is also presented.

  10. Instantaneous Bethe-Salpeter kernel for the lightest pseudoscalar mesons

    NASA Astrophysics Data System (ADS)

    Lucha, Wolfgang; Schöberl, Franz F.

    2016-05-01

    Starting from a phenomenologically successful, numerical solution of the Dyson-Schwinger equation that governs the quark propagator, we reconstruct in detail the interaction kernel that has to enter the instantaneous approximation to the Bethe-Salpeter equation to allow us to describe the lightest pseudoscalar mesons as quark-antiquark bound states exhibiting the (almost) masslessness necessary for them to be interpretable as the (pseudo) Goldstone bosons related to the spontaneous chiral symmetry breaking of quantum chromodynamics.

  11. Speed Scaling for Energy and Performance with Instantaneous Parallelism

    NASA Astrophysics Data System (ADS)

    Sun, Hongyang; He, Yuxiong; Hsu, Wen-Jing

    We consider energy-performance tradeoff for scheduling parallel jobs on multiprocessors using dynamic speed scaling. The objective is to minimize the sum of energy consumption and certain performance metric, including makespan and total flow time. We focus on designing algorithms that are aware of the jobs' instantaneous parallelism but not their characteristics in the future. For total flow time plus energy, it is known that any algorithm that does not rely on instantaneous parallelism is Ω(ln 1/α P)-competitive, where P is the total number of processors. In this paper, we demonstrate the benefits of knowing instantaneous parallelism by presenting an O(1)-competitive algorithm. In the case of makespan plus energy, which is considered in the literature for the first time, we present an O(ln 1 - 1/α P)-competitive algorithm for batched jobs consisting of fully-parallel and sequential phases. We show that this algorithm is asymptotically optimal by providing a matching lower bound.

  12. Measurement and analysis of instantaneous torque and angular velocity variations of a low speed two stroke diesel engine

    NASA Astrophysics Data System (ADS)

    Jiménez Espadafor, Francisco J.; A. Becerra Villanueva, José; Palomo Guerrero, Daniel; Torres García, Miguel; Carvajal Trujillo, Elisa; Fernández Vacas, Francisco

    2014-12-01

    This paper presents an investigation into the potential of using direct measurement of engine torque for diagnostic purposes in large engines - in this case applied to power generation. The procedures for measuring and analyzing the instantaneous torque, the angular displacement on the generator output end and the angular displacement on its free end for a ten-cylinder, low speed two stroke diesel engine are presented. Angular speed oscillations are frequently used for combustion engine diagnostics although they cannot be used to measure engine power directly. In addition, and for engines with huge inertia generators such as those used in power plants, speed oscillations are very low and this reduces the signal to noise ratio and makes the evaluation of the instantaneous angular speed very noisy. In the work described here, torque and angular displacement measurements carried out at the same point and with the same engine conditions are compared and the superior performance of torque is demonstrated. Harmonic analysis of instantaneous torque allowed the identification of the dynamic characteristics of the power train of the diesel group and clearly suggests that this signal can be used as a diagnostic tool for excitation, combustion malfunctions, or for the mechanical characteristics of the system and crankshaft stiffness. The torque distortion introduced by the generator due to the discontinuity imposed by the pole pairs is also observed in the torque signal, suggesting that the torque signal can be used to identify generator malfunction.

  13. A New Instantaneous Frequency Measure Based on The Stockwell Transform

    NASA Astrophysics Data System (ADS)

    yedlin, M. J.; Ben-Horrin, Y.; Fraser, J. D.

    2011-12-01

    We propose the use of a new transform, the Stockwell transform[1], as a means of creating time-frequency maps and applying them to distinguish blasts from earthquakes. This new transform, the Stockwell transform can be considered as a variant of the continuous wavelet transform, that preserves the absolute phase.The Stockwell transform employs a complex Morlet mother wavelet. The novelty of this transform lies in its resolution properties. High frequencies in the candidate signal are well-resolved in time but poorly resolved in frequency, while the converse is true for low frequency signal components. The goal of this research is to obtain the instantaneous frequency as a function of time for both the earthquakes and the blasts. Two methods will be compared. In the first method, we will compute the analytic signal, the envelope and the instantaneous phase as a function of time[2]. The instantaneous phase derivative will yield the instantaneous angular frequency. The second method will be based on time-frequency analysis using the Stockwell transform. The Stockwell transform will be computed in non-redundant fashion using a dyadic representation[3]. For each time-point, the frequency centroid will be computed -- a representation for the most likely frequency at that time. A detailed comparison will be presented for both approaches to the computation of the instantaneous frequency. An advantage of the Stockwell approach is that no differentiation is applied. The Hilbert transform method can be less sensitive to edge effects. The goal of this research is to see if the new Stockwell-based method could be used as a discriminant between earthquakes and blasts. References [1] Stockwell, R.G., Mansinha, L. and Lowe, R.P. "Localization of the complex spectrum: the S transform", IEEE Trans. Signal Processing, vol.44, no.4, pp.998-1001, (1996). [2]Taner, M.T., Koehler, F. "Complex seismic trace analysis", Geophysics, vol. 44, Issue 6, pp. 1041-1063 (1979). [3] Brown, R

  14. Sodium nitrite enhances generation of reactive oxygen species that decrease antioxidant power and inhibit plasma membrane redox system of human erythrocytes.

    PubMed

    Ansari, Fariheen Aisha; Mahmood, Riaz

    2016-08-01

    Nitrite/nitrate salts are used in fertilizers and as food preservatives. Human exposure to high levels of nitrite results in its uptake and subsequent entry into blood where it can interact with erythrocytes. We show that treatment of human erythrocytes with sodium nitrite (NaNO2 ) results in a dose-dependent increase in the production of reactive oxygen species. This was accompanied by a decrease in the antioxidant power which lowered the free radical quenching and metal-reducing ability. NaNO2 treatment also inhibited plasma membrane redox system (PMRS) of erythrocytes. These changes increase the susceptibility of erythrocytes to oxidative damage, decrease the antioxidant power of whole blood, and can be a major cause of nitrite-induced cellular toxicity. PMID:27214747

  15. Sodium nitrite enhances generation of reactive oxygen species that decrease antioxidant power and inhibit plasma membrane redox system of human erythrocytes.

    PubMed

    Ansari, Fariheen Aisha; Mahmood, Riaz

    2016-08-01

    Nitrite/nitrate salts are used in fertilizers and as food preservatives. Human exposure to high levels of nitrite results in its uptake and subsequent entry into blood where it can interact with erythrocytes. We show that treatment of human erythrocytes with sodium nitrite (NaNO2 ) results in a dose-dependent increase in the production of reactive oxygen species. This was accompanied by a decrease in the antioxidant power which lowered the free radical quenching and metal-reducing ability. NaNO2 treatment also inhibited plasma membrane redox system (PMRS) of erythrocytes. These changes increase the susceptibility of erythrocytes to oxidative damage, decrease the antioxidant power of whole blood, and can be a major cause of nitrite-induced cellular toxicity.

  16. An analysis of thermionic space nuclear reactor power system: I. Effect of disassembling radial reflector, following a reactivity initiated accident

    SciTech Connect

    El-Genk, M.S.; Paramonov, D. )

    1993-01-10

    An analysis is performed to determine the effect of disassembling the radial reflector of the TOPAZ-II reactor, following a hypothetical severe Reactivity Initiated Accident (RIA). Such an RIA is assumed to occur during the system start-up in orbit due to a malfunction of the drive mechanism of the control drums, causing the drums to rotate the full 180[degree] outward at their maximum speed of 1.4[degree]/s. Results indicate that disassembling only three of twelve radial reflector panels would successfully shutdown the reactor, with little overheating of the fuel and the moderator.

  17. Emission factors for passenger cars: application of instantaneous emission modeling

    NASA Astrophysics Data System (ADS)

    de Haan, Peter; Keller, Mario

    This paper discusses the use of 'instantaneous' high-resolution (1 Hz) emission data for the estimation of passenger car emissions during real-world driving. Extensive measurements of 20 EURO-I gasoline passenger cars have been used to predict emission factors for standard (i.e. legislative) as well as non-standard (i.e. real-world) driving patterns. It is shown that emission level predictions based upon chassis dynamometer tests over standard driving cycles significantly underestimate emission levels during real-world driving. The emission characteristics of modern passenger cars equipped with a three-way catalytic converter are a low, basic emission level on the one hand, and frequent emission 'peaks' on the other. For real-world driving, up to one-half of the entire emission can be emitted during these short-lasting peaks. Their frequency depends on various factors, including the level of 'dynamics' (speed variation) of the driving pattern. Because of this, the use of average speed as the only parameter to characterize emissions over a specific driving pattern is not sufficient. The instantaneous emissions approach uses an additional parameter representing engine load in order to resolve the differences between driving patterns with comparable average speeds but different levels of 'dynamics'. The paper includes an investigation of different statistical indicators and discusses methods to further improve the prediction capability of the instantaneous emission approach. The fundamental differences in emission-reduction strategies between different car manufacturers make the task of constructing a model valid for all catalyst passenger cars seemingly impossible, if the model is required to predict both fleet-averaged emission levels and emission factors for driving patterns of short duration for individual vehicles simultaneously.

  18. Evanescent Modes and Tunnelling Instantaneously Act at a Distance

    SciTech Connect

    Nimtz, Guenter; Stahlhofen, Alfons A.

    2008-03-06

    Photonic tunnelling experiments have shown that i) the Einstein energy relation is violated, ii) the tunnelling process is non-local, iii) the signal velocity is faster than light, i.e. superluminal, iv) the tunnelling signal is not observable, since photonic tunnelling is described by virtual photons, and v) according to the experimental results the signal velocity is infinite inside the barriers, implying that tunnelling instantaneously acts at a distance. We think these properties are not compatible with the claims of many text books on Special Relativity.

  19. Multidimensional displacement vector measurement methods utilizing instantaneous phase.

    PubMed

    Sumi, Chikayoshi

    2005-01-01

    In this report, we propose two new methods for measuring multidimensional displacement vector using instantaneous ultrasound signal phase, i.e., the multidimensional autocorrelation method and the multidimensional Doppler's method. In order to realize high measurement accuracy, respective displacement vector measurement methods are combined with our proposed useful lateral modulation method, i.e., the lateral Gaussian envelop cosine modulation method. We further report measurement accuracy evaluated through simulations. These methods can be applied to tissue strain measurement, blood flow measurement, sonar measurement, etc.

  20. Instantaneous planar visualization of reacting supersonic flows using silane seeding

    NASA Technical Reports Server (NTRS)

    Smith, Michael W.; Northam, G. B.

    1991-01-01

    A new visualization technique for reacting flows has been developed. This technique, which is suitable for supersonic combustion flows, has been demonstrated on a scramjet combustor model. In this application, gaseous silane (SiH4) was added to the primary hydrogen fuel. When the fuel reacted, so did the (SiH4), producing silica (SiO2) particles in situ. The particles were illuminated with a laser sheet formed from a frequency-doubled Nd:YAG laser (532 nm) beam and the Mie scattering signal was imaged. These planar images of the silica Mie scattering provided instantaneous 'maps' of combustion progress within the turbulent reacting flowfield.

  1. A Simple Instant-Estimation Method for Time-Average Quantities of Single-Phase Power and Application to Single-Phase Power Grid Connection by Inverter

    NASA Astrophysics Data System (ADS)

    Shinnaka, Shinji

    This paper presents and analyzes a new simple instant-estimation method for time-average quantities such as rms-values of voltage and current, active and reactive powers, and power factor for single-phase power with the fundamental component of constant or nearly-constant frequency by measuring instantaneous values of voltage and current. According to the analyses, the method can instantly estimate time average values with accuracy of the fundamental frequency, and estimation accuracy of power factor is about two times better than that of voltage, current, and powers. The instant-estimation method is simple and can be easily applied to single-phase power control systems that are expected to control instantly and continuously power factor on a single-phase grid by inverter. Based on the proposed instant-estimation method, two-methods for such power control systems are also proposed and their usefulness is verified through simulations.

  2. Export of reactive nitrogen from coal-fired power plants in the U.S.: Estimates from a plume-in-grid modeling study - article no. D04308

    SciTech Connect

    Vijayaraghavan, K.; Zhang, Y.; Seigneur, C.; Karamchandani, P.; Snell, H.E.

    2009-02-15

    The export of reactive nitrogen (nitrogen oxides and their oxidation products, collectively referred to as NOy) from coal-fired power plants in the U.S. to the rest of the world could have a significant global contribution to ozone. Traditional Eulerian gridded air quality models cannot characterize accurately the chemistry and transport of plumes from elevated point sources such as power plant stacks. A state-of-the-science plume-in-grid (PinG) air quality model, a reactive plume model embedded in an Eulerian gridded model, is used to estimate the export of NOy from 25 large coal-fired power plants in the U. S. (in terms of NOx and SO{sub 2} emissions) in July 2001 to the global atmosphere. The PinG model used is the Community Multiscale Air Quality Model with Advanced Plume Treatment (CMAQ-APT). A benchmark simulation with only the gridded model, CMAQ, is also conducted for comparison purposes. The simulations with and without advanced plume treatment show differences in the calculated export of NOy from the 25 plants considered reflecting the effect of using a detailed and explicit treatment of plume transport and chemistry. The advanced plume treatment results in 31% greater simulated export of NOy compared to the purely grid-based modeling approach. The export efficiency of NOy (the fraction of NOy emitted that is exported) is predicted to be 21% without APT and 27% with APT. When considering only export through the eastern boundary across the Atlantic, CMAQ-APT predicts that the export efficiency is 24% and that 2% of NOy is exported as NOx, 49% as inorganic nitrate, and 25% as PAN. These results are in reasonably good agreement with an analysis reported in the literature of aircraft measurements over the North Atlantic.

  3. Instantaneous nitric oxide effect on secondary organic aerosol formation from m-xylene photooxidation

    NASA Astrophysics Data System (ADS)

    Li, Lijie; Tang, Ping; Cocker, David R.

    2015-10-01

    Secondary organic aerosol (SOA) formation from aromatic hydrocarbon photooxidation is highly sensitive to NO concentration. The instantaneous effect of NO on SOA formation from m-xylene photooxidation is investigated in this work by data mining 10 years of aromatic hydrocarbon chamber experiments conducted in the UC Riverside/CE-CERT chamber. First, the effect of sub-ppb NO concentrations on SOA formation is explored. The relationship of SOA growth rate to 1) NO2/NO ratio; 2) instantaneous HC/NO; 3) absolute NO concentration; 4) peroxy radical reaction branching ratio and 5) hydroxyl radical concentration are illustrated. Second, continuous and stepwise NO, NO2 and HONO injection are applied to m-xylene photooxidation experiments to simulate continuous NO sources in an urban area. The influence of these reaction scenarios on radical concentrations and SOA formation is explored. [HO2rad ]/[RO2rad ] shows a strong correlation with SOA yields in addition to [rad OH]/[HO2rad ], [rad OH], [HO2rad ] and [RO2rad ]. Enhanced SOA formation is observed when low NO levels (<1 ppb) are artificially maintained by continuous or step-wise injection; consistent with earlier research, SOA formation is observed to be suppressed by large initial NO injections. It is proposed that NO at sub-ppb level enhances rad OH formation increasing HO2rad and RO2rad and therefore promoting SOA formation. Further, two NO pathways (one promoting and one suppressing SOA formation) and one extremely low NO phase (NO "free") are used to demonstrate the evolution of NO impact on SOA formation during photooxidation. This study implies that SOA yields from aromatic hydrocarbon and low NOx photooxidation is previously underestimated due to differences between traditional environmental chamber experiments and atmospheric reactivity.

  4. Estimating instantaneous peak flow from mean daily flow

    NASA Astrophysics Data System (ADS)

    Chen, B.; Krajewski, W. F.

    2015-12-01

    While instantaneous peak flow (IPF) records have historically been necessary for practical applications in flood risk management and hydraulic structure design, mean daily flow (MDF) values are often all that are available. To address this problem, we propose a simple method, which requires only MDF records as its input and uses the rising and falling slopes of daily hydrographs, to estimate IPFs. We applied this method to 144 catchments in Iowa, USA, with drainage areas ranging from about 7 to 220,000 km2. This application involves about 3800 peak flow events originating from different flood generation mechanisms over the period from 1997 to 2014. About 55% of the catchments have prediction errors within ±10%, and 85% of the catchments have predictions errors within ±20%. The method works well for catchments larger than 500 km2, poorly for catchments smaller than 100 km2, and fairly well for catchments in between these sizes. The reduction in the method's effectiveness with decreasing catchment size is due to the fact that the smaller the catchment, the more information is lost when using MDF to characterize the instantaneous flow processes. Our proposed method is simple and promising in terms of estimating IPFs from MDFs for areas where IPF records are unavailable or are insufficient.

  5. Instantaneous Wavenumber Estimation for Damage Quantification in Layered Plate Structures

    NASA Technical Reports Server (NTRS)

    Mesnil, Olivier; Leckey, Cara A. C.; Ruzzene, Massimo

    2014-01-01

    This paper illustrates the application of instantaneous and local wavenumber damage quantification techniques for high frequency guided wave interrogation. The proposed methodologies can be considered as first steps towards a hybrid structural health monitoring/ nondestructive evaluation (SHM/NDE) approach for damage assessment in composites. The challenges and opportunities related to the considered type of interrogation and signal processing are explored through the analysis of numerical data obtained via EFIT simulations of damage in CRFP plates. Realistic damage configurations are modeled from x-ray CT scan data of plates subjected to actual impacts, in order to accurately predict wave-damage interactions in terms of scattering and mode conversions. Simulation data is utilized to enhance the information provided by instantaneous and local wavenumbers and mitigate the complexity related to the multi-modal content of the plate response. Signal processing strategies considered for this purpose include modal decoupling through filtering in the frequency/wavenumber domain, the combination of displacement components, and the exploitation of polarization information for the various modes as evaluated through the dispersion analysis of the considered laminate lay-up sequence. The results presented assess the effectiveness of the proposed wavefield processing techniques as a hybrid SHM/NDE technique for damage detection and quantification in composite, plate-like structures.

  6. A parametric estimation approach to instantaneous spectral imaging.

    PubMed

    Oktem, Figen S; Kamalabadi, Farzad; Davila, Joseph M

    2014-12-01

    Spectral imaging, the simultaneous imaging and spectroscopy of a radiating scene, is a fundamental diagnostic technique in the physical sciences with widespread application. Due to the intrinsic limitation of two-dimensional (2D) detectors in capturing inherently three-dimensional (3D) data, spectral imaging techniques conventionally rely on a spatial or spectral scanning process, which renders them unsuitable for dynamic scenes. In this paper, we present a nonscanning (instantaneous) spectral imaging technique that estimates the physical parameters of interest by combining measurements with a parametric model and solving the resultant inverse problem computationally. The associated inverse problem, which can be viewed as a multiframe semiblind deblurring problem (with shift-variant blur), is formulated as a maximum a posteriori (MAP) estimation problem since in many such experiments prior statistical knowledge of the physical parameters can be well estimated. Subsequently, an efficient dynamic programming algorithm is developed to find the global optimum of the nonconvex MAP problem. Finally, the algorithm and the effectiveness of the spectral imaging technique are illustrated for an application in solar spectral imaging. Numerical simulation results indicate that the physical parameters can be estimated with the same order of accuracy as state-of-the-art slit spectroscopy but with the added benefit of an instantaneous, 2D field-of-view. This technique will be particularly useful for studying the spectra of dynamic scenes encountered in space remote sensing. PMID:25347878

  7. Instantaneous temperature visualization of a turbulent flame using multidirectional interferometer

    NASA Astrophysics Data System (ADS)

    Doi, Junta; Sato, Seishiro

    2005-03-01

    We have reconstructed a three-dimensional instantaneous temperature distribution inside a turbulent flame of a propane-air premixed burner using multidirectional holographic interferograms and visualized by constructing a geometric model of the three-dimensional isothermal surfaces. To reconstruct a three-dimensional asymmetric temperature field, the interference fringe data were acquired using an eight-directional Twyman-Green interferometer, over a full range of viewing angles, around the object flame, and all data are simultaneously acquired. A ruby laser, having a beam with a 20-30 ns pulse width, was used to obtain clear fringe patterns for this type of turbulent phenomena. The temperature distribution was reconstructed from the refractive index distribution, obtained from the fringe patterns, based on a computed tomography technique of a convolution reconstruction algorithm. Isothermal profiles were calculated in horizontal cross sections from the temperature data. All of the multiple isothermal contour lines in each horizontal section were approximated with polygons and then stacked up vertically to form polyhedra of the solid model format, having side facets of corresponding isothermal values. Computer graphics of the solid models, not only of the initial isothermal solids, but also of the solids resulting from multiple Boolean operations on them, were used to show the distribution in detail. This development will be of help in studying the local structure of the instantaneous turbulent flame and in integrating the experimental modeling with the numerical simulation.

  8. 2-Iodoxybenzoic acid organosulfonates: preparation, X-ray structure and reactivity of new, powerful hypervalent iodine(V) oxidants.

    PubMed

    Yusubov, Mekhman S; Svitich, Dmitrii Yu; Yoshimura, Akira; Nemykin, Victor N; Zhdankin, Viktor V

    2013-12-14

    New powerful hypervalent iodine(V) oxidants, tosylate and mesylate derivatives of 2-iodoxybenzoic acid (IBX), were prepared by the reaction of IBX with the corresponding sulfonic acids. Single crystal X-ray crystallography of the diacetate derivative of IBX-tosylate revealed an unusual heptacoordinated iodine geometry without any significant intermolecular secondary interactions.

  9. Analytical Solution for Reactive Solute Transport Considering Incomplete Mixing

    NASA Astrophysics Data System (ADS)

    Bellin, A.; Chiogna, G.

    2013-12-01

    The laboratory experiments of Gramling et al. (2002) showed that incomplete mixing at the pore scale exerts a significant impact on transport of reactive solutes and that assuming complete mixing leads to overestimation of product concentration in bimolecular reactions. We consider here the family of equilibrium reactions for which the concentration of the reactants and the product can be expressed as a function of the mixing ratio, the concentration of a fictitious non reactive solute. For this type of reactions we propose, in agreement with previous studies, to model the effect of incomplete mixing at scales smaller than the Darcy scale assuming that the mixing ratio is distributed within an REV according to a Beta distribution. We compute the parameters of the Beta model by imposing that the mean concentration is equal to the value that the concentration assumes at the continuum Darcy scale, while the variance decays with time as a power law. We show that our model reproduces the concentration profiles of the reaction product measured in the Gramling et al. (2002) experiments using the transport parameters obtained from conservative experiments and an instantaneous reaction kinetic. The results are obtained applying analytical solutions both for conservative and for reactive solute transport, thereby providing a method to handle the effect of incomplete mixing on multispecies reactive solute transport, which is simpler than other previously developed methods. Gramling, C. M., C. F. Harvey, and L. C. Meigs (2002), Reactive transport in porous media: A comparison of model prediction with laboratory visualization, Environ. Sci. Technol., 36(11), 2508-2514.

  10. Reactive arthritis

    PubMed Central

    Hind, C. R. K.

    1982-01-01

    Reactive arthritis is a rare complication of certain infections. The similar features and HLA associations with the seronegative arthropathies have raised the possibility that the latter may be forms of reactive arthritis. This review describes the clinical and epidemiological features, and the recent advances in our understanding of the underlying pathogenesis of reactive arthritis. PMID:7100033

  11. NDE evaluation of the intergranular corrosion susceptibility of a 2205 duplex stainless steel using thermoelectric power and double loop electrochemical potentiokinetic reactivation methods

    NASA Astrophysics Data System (ADS)

    Ortiz, N.; Carreón, H.; Ruiz, A.

    2013-01-01

    There is a need for a nondestructive technique to assess rapidly and with confidence the degree of sensitization (DOS) in duplex stainless steel (DSS). In this investigation, we present the use of thermoelectric power (TEP) measurements as nondestructive method for the determination of DOS in isothermally aged 2205 DSS at 700°C for different aging times. The DOS of the aged samples was first established by performing the double loop electrochemical potentiokinetic reactivation (DL-EPR) test. The microstructural evolution was evaluated by scanning electron microscopy (SEM). Experimental results indicate that TEP coefficient is sensitive to gradual microstructural changes produced by thermal aging and can be used to monitor IGC sensitization of 2205 duplex stainless steel.

  12. Instantaneous signal attenuation method for analysis of PFG fractional diffusions

    NASA Astrophysics Data System (ADS)

    Lin, Guoxing

    2016-08-01

    An instantaneous signal attenuation (ISA) method for analyzing pulsed field gradient (PFG) fractional diffusion (FD) has been developed, which is modified from the propagator approach developed in 2001 by Lin et al. for analyzing PFG normal diffusion. Both, the current ISA method and the propagator method have the same fundamental basis that the total signal attenuation (SA) is the accumulation of all the ISA, and the ISA is the average SA of the whole diffusion system at each moment. However, the manner of calculating ISA is different. Unlike the use of the instantaneous propagator in the propagator method, the current method directly calculates ISA as A(K(t‧), t‧ + dt‧)/A(K(t‧), t‧), where A(K(t‧), t‧ + dt‧) and A(K(t‧), t‧) are the SA. This modification makes the current method applicable to PFG FD as the instantaneous propagator may not be obtainable in FD. The ISA method was applied to study PFG SA including the effect of finite gradient pulse widths (FGPW) for free FD, restricted FD and the FD affected by a non-homogeneous gradient field. The SA expressions were successfully obtained for all three types of free FDs while other current methods still have difficulty in obtaining all of them. The results from this method agree with reported results such as that obtained by the effective phase shift diffusion equation (EPSDE) method. The M-Wright phase distribution approximation was also used to derive an SA expression for time FD as a comparison, which agrees with ISA method. Additionally, the continuous-time random walk (CTRW) simulation was performed to simulate the SA of PFG FD, and the simulation results agree with the analytical results. Particularly, the CTRW simulation results give good support to the analytical results including FGPW effect for free FD and restricted time FD based on a fractional derivative model where there have been no corresponding theoretical reports to date. The theoretical SA expressions including FGPW obtained

  13. Instantaneous signal attenuation method for analysis of PFG fractional diffusions.

    PubMed

    Lin, Guoxing

    2016-08-01

    An instantaneous signal attenuation (ISA) method for analyzing pulsed field gradient (PFG) fractional diffusion (FD) has been developed, which is modified from the propagator approach developed in 2001 by Lin et al. for analyzing PFG normal diffusion. Both, the current ISA method and the propagator method have the same fundamental basis that the total signal attenuation (SA) is the accumulation of all the ISA, and the ISA is the average SA of the whole diffusion system at each moment. However, the manner of calculating ISA is different. Unlike the use of the instantaneous propagator in the propagator method, the current method directly calculates ISA as A(K(t'),t'+dt')/A(K(t'),t'), where A(K(t'),t'+dt') and A(K(t'),t') are the SA. This modification makes the current method applicable to PFG FD as the instantaneous propagator may not be obtainable in FD. The ISA method was applied to study PFG SA including the effect of finite gradient pulse widths (FGPW) for free FD, restricted FD and the FD affected by a non-homogeneous gradient field. The SA expressions were successfully obtained for all three types of free FDs while other current methods still have difficulty in obtaining all of them. The results from this method agree with reported results such as that obtained by the effective phase shift diffusion equation (EPSDE) method. The M-Wright phase distribution approximation was also used to derive an SA expression for time FD as a comparison, which agrees with ISA method. Additionally, the continuous-time random walk (CTRW) simulation was performed to simulate the SA of PFG FD, and the simulation results agree with the analytical results. Particularly, the CTRW simulation results give good support to the analytical results including FGPW effect for free FD and restricted time FD based on a fractional derivative model where there have been no corresponding theoretical reports to date. The theoretical SA expressions including FGPW obtained here such as [Formula: see

  14. Mammalian energetics. Instantaneous energetics of puma kills reveal advantage of felid sneak attacks.

    PubMed

    Williams, Terrie M; Wolfe, Lisa; Davis, Tracy; Kendall, Traci; Richter, Beau; Wang, Yiwei; Bryce, Caleb; Elkaim, Gabriel Hugh; Wilmers, Christopher C

    2014-10-01

    Pumas (Puma concolor) live in diverse, often rugged, complex habitats. The energy they expend for hunting must account for this complexity but is difficult to measure for this and other large, cryptic carnivores. We developed and deployed a physiological SMART (species movement, acceleration, and radio tracking) collar that used accelerometry to continuously monitor energetics, movements, and behavior of free-ranging pumas. This felid species displayed marked individuality in predatory activities, ranging from low-cost sit-and-wait behaviors to constant movements with energetic costs averaging 2.3 times those predicted for running mammals. Pumas reduce these costs by remaining cryptic and precisely matching maximum pouncing force (overall dynamic body acceleration = 5.3 to 16.1g) to prey size. Such instantaneous energetics help to explain why most felids stalk and pounce, and their analysis represents a powerful approach for accurately forecasting resource demands required for survival by large, mobile predators.

  15. Instantaneous and efficient surface wave excitation of a low pressure gas or gases

    DOEpatents

    Levy, Donald J.; Berman, Samuel M.

    1988-01-01

    A system for instantaneously ionizing and continuously delivering energy in the form of surface waves to a low pressure gas or mixture of low pressure gases, comprising a source of rf energy, a discharge container, (such as a fluorescent lamp discharge tube), an rf shield, and a coupling device responsive to rf energy from the source to couple rf energy directly and efficiently to the gas or mixture of gases to ionize at least a portion of the gas or gases and to provide energy to the gas or gases in the form of surface waves. The majority of the rf power is transferred to the gas or gases near the inner surface of the discharge container to efficiently transfer rf energy as excitation energy for at least one of the gases. The most important use of the invention is to provide more efficient fluorescent and/or ultraviolet lamps.

  16. Instantaneous physico-chemical analysis of suspension-based nanomaterials

    PubMed Central

    Meng, Fanxu; Ugaz, Victor M.

    2015-01-01

    High-throughput manufacturing of nanomaterial-based products demands robust online characterization and quality control tools capable of continuously probing the in-suspension state. But existing analytical techniques are challenging to deploy in production settings because they are primarily geared toward small-batch ex-situ operation in research laboratory environments. Here we introduce an approach that overcomes these limitations by exploiting surface complexation interactions that emerge when a micron-scale chemical discontinuity is established between suspended nanoparticles and a molecular tracer. The resulting fluorescence signature is easily detectable and embeds surprisingly rich information about composition, quantity, size, and morphology of nanoparticles in suspension independent of their agglomeration state. We show how this method can be straightforwardly applied to enable continuous sizing of commercial ZnO nanoparticles, and to instantaneously quantify the anatase and rutile composition of multicomponent TiO2 nanoparticle mixtures pertinent to photocatalysis and solar energy conversion. PMID:25923196

  17. [Detonation temperature measurement of epoxypropane using instantaneous spectrum method].

    PubMed

    Li, Ying; Li, Ping; Xiao, Hai-Bo; Hu, Dong; Yuan, Chang-Ying

    2008-03-01

    After solving the problems of synchronization of the measuring system and the avoidance of false trigger signal, the instantaneous emission spectrum of epoxypropane with an exposure time of 2 micros and a resolution of 0.2 nm was acquired from a side window of a shock tube at the very moment when the epoxypropane transformed from deflagration to detonation. The measuring system consists of an advanced intensified charge-coupled-device spectroscopic detector, a digital delay generator DG535, an explosion shock tube and optical fibers. The DDT process was monitored by pressure transducers. After correcting the intensity of the spectrum obtained, the background curve of the heat radiation intensity of the detonation was given immediately. The detonation temperature of 2 416 K for epoxypropane was derived from fitting the curve with Planck blackbody formula by least squares principle. The detonation temperature of epoxypropane can provide an experimental datum for analyzing the microscopic mechanism of DDT process. PMID:18536396

  18. Video measurements of instantaneous forces of flapping wing vehicles

    NASA Astrophysics Data System (ADS)

    Jennings, Alan; Mayhew, Michael; Black, Jonathan

    2015-12-01

    Flapping wings for small aerial vehicles have revolutionary potential for maneuverability and endurance. Ornithopters fail to achieve the performance of their biological equivalents, despite extensive research on how animals fly. Flapping wings produce peak forces due to the stroke reversal of the wing. This research demonstrates in-flight measurements of an ornithopter through the use of image processing, specifically measuring instantaneous forces. Results show that the oscillation about the flight path is significant, being about 20% of the mean velocity and up to 10 g's. Results match forces with deformations of the wing to contrast the timing and wing shape of the upstroke and the downstroke. Holding the vehicle fixed (e.g. wind tunnel testing or simulations) structural resonance is affected along with peak forces, also affecting lift. Non-contact, in-flight measurements are proposed as the best method for matching the flight conditions of flapping wing vehicles.

  19. [Detonation temperature measurement of epoxypropane using instantaneous spectrum method].

    PubMed

    Li, Ying; Li, Ping; Xiao, Hai-Bo; Hu, Dong; Yuan, Chang-Ying

    2008-03-01

    After solving the problems of synchronization of the measuring system and the avoidance of false trigger signal, the instantaneous emission spectrum of epoxypropane with an exposure time of 2 micros and a resolution of 0.2 nm was acquired from a side window of a shock tube at the very moment when the epoxypropane transformed from deflagration to detonation. The measuring system consists of an advanced intensified charge-coupled-device spectroscopic detector, a digital delay generator DG535, an explosion shock tube and optical fibers. The DDT process was monitored by pressure transducers. After correcting the intensity of the spectrum obtained, the background curve of the heat radiation intensity of the detonation was given immediately. The detonation temperature of 2 416 K for epoxypropane was derived from fitting the curve with Planck blackbody formula by least squares principle. The detonation temperature of epoxypropane can provide an experimental datum for analyzing the microscopic mechanism of DDT process.

  20. Full field imaging based instantaneous hyperspectral absolute refractive index measurement

    SciTech Connect

    Baba, Justin S; Boudreaux, Philip R

    2012-01-01

    Multispectral refractometers typically measure refractive index (RI) at discrete monochromatic wavelengths via a serial process. We report on the demonstration of a white light full field imaging based refractometer capable of instantaneous multispectral measurement of absolute RI of clear liquid/gel samples across the entire visible light spectrum. The broad optical bandwidth refractometer is capable of hyperspectral measurement of RI in the range 1.30 1.70 between 400nm 700nm with a maximum error of 0.0036 units (0.24% of actual) at 414nm for a = 1.50 sample. We present system design and calibration method details as well as results from a system validation sample.

  1. Shaft instantaneous angular speed for blade vibration in rotating machine

    NASA Astrophysics Data System (ADS)

    Gubran, Ahmed A.; Sinha, Jyoti K.

    2014-02-01

    Reliable blade health monitoring (BHM) in rotating machines like steam turbines and gas turbines, is a topic of research since decades to reduce machine down time, maintenance costs and to maintain the overall safety. Transverse blade vibration is often transmitted to the shaft as torsional vibration. The shaft instantaneous angular speed (IAS) is nothing but the representing the shaft torsional vibration. Hence the shaft IAS has been extracted from the measured encoder data during machine run-up to understand the blade vibration and to explore the possibility of reliable assessment of blade health. A number of experiments on an experimental rig with a bladed disk were conducted with healthy but mistuned blades and with different faults simulation in the blades. The measured shaft torsional vibration shows a distinct difference between the healthy and the faulty blade conditions. Hence, the observations are useful for the BHM in future. The paper presents the experimental setup, simulation of blade faults, experiments conducted, observations and results.

  2. Instantaneous engine frictional torque, its components and piston assembly friction

    SciTech Connect

    Nichols, F.A. ); Henein, N.A. . Center for Automotive Research)

    1992-05-01

    The overall goal of this report is to document the work done to determine the instantaneous frictional torque of internal combustion engine by using a new approach known as (P-[omega]) method developed at Wayne State University. The emphasis has been to improve the accuracy of the method, and apply it to both diesel and gasoline engines under different operating conditions. Also work included an investigation to determine the effect of using advanced materials and techniques to coat the piston rings on the instantaneous engine frictional torque and the piston assembly friction. The errors in measuring the angular velocity, [omega], have been determined and found to be caused by variations in the divisions within one encoder, encoder-to-encoder variations, misalignment within the encoder itself and misalignment between the encoder and crankshaft. The errors in measuring the cylinder gas pressure, P, have been determined and found to be caused by transducer-to-transducer variations, zero drift, thermal stresses and lack of linearity. The ability of the (P-[omega]) method in determining the frictional torque of many engine components has been demonstrated. These components include valve train, fuel injection pump with and without fuel injection, and piston with and without different ring combinations. The emphasis in this part of the research program has been on the piston-ring assembly friction. The effects of load and other operating variables on IFT have been determined. The motoring test, which is widely used in industry to measure engine friction has been found to be inaccurate. The errors have been determined at different loads.

  3. Instantaneous gravitational and inertial action-at-a-distance.

    NASA Astrophysics Data System (ADS)

    Pope, N. V.; Osborne, A. D.

    All physical systems balance. In energy and angular momentum terms, a galaxy is as balanced as a flywheel. The scandal in modern physics is that Einstein presented his theory of relativity in such a way that no balancing influence - indeed, no physical influence whatsoever - can pass between bodies faster than the speed of light. This makes it seem miraculous that the physical world holds together in the way it does without "spooky superluminal actions-at-a-distance" being responsible for this holistic integrity. Some believe, therefore, as did Einstein - that relativity makes no provision for any such nonlocal interaction; hence the steadily growing number of experimental evidences of such interaction seems to disprove relativity. The authors think this is a confusion created by Einstein's unnecessary interpretation of the constant c as the "velocity of light in vacuo". In relativity, proper-time-instantaneity provides all that is necessary for balanced holistic interaction. The authors therefore support relativity from the standpoint of modern philosophy, the only departure being to replace Einstein's velocity of light with Bondi's more economical interpretation of c as a constant for converting observational distances in meters into times in seconds. Without affecting the value and dimensions of c, this profoundly alters the philosophical consequences of the theory, making it more conceptually economical and more compatible with the ideas of Einstein's philosophical mentor and critic, Mach, regarding the instantaneity of distant gravitational and inertial interaction. The authors regard the conservation laws as sufficient in themselves to explain the motions of bodies in relation to one another without need of forces acting between them, either at or faster than the speed of light. This paper is part of an ongoing mathematics/philosophy project at Keele University, both the strength and weakness of which lie in the combining of arts and science in a way that is

  4. Instantaneous mantle dynamics of the Western Mediterranean region

    NASA Astrophysics Data System (ADS)

    Mohammadi, S.; Geenen, T.; van den Berg, A. P.; Spakman, W.

    2012-04-01

    Our research is concerned with the establishment of links between deep mantle processes and surface deformation. Our main focus is on the instantaneous mantle dynamics of the European-Mediterranean region and its surface responses. Here we have constructed instantaneous 3-D dynamic models of the Western Mediterranean region with focus on subduction below Betic-Rif-Alboran region. The driving forces in the models are due to temperature variation, which is derived from seismic tomography. The tomography model, which is used in our research, is the global P-wave speed model UU-P07 (M. Amaru, PhD Thesis, Utrecht University, 2007; Van der Meer et al., Nature Geoscience, 2010). For the subducted slab in this region we have assumed a temperature profile according to the Jurassic-Early Cretaceous age of the oceanic lithosphere. The boundary conditions used in the dynamic models allow us to include constraints from motions of the larger tectonic plates regarding the convergence of African and Eurasian plates. We present the topography response and the predicted patterns of surface deformations for this region based on a number of assumptions regarding the scaling of tomography to temperature and density, and rheology. A depth and temperature dependent rheology is assumed for most of the domain. Lithosphere faults are modeled with low viscosity zones. The mesh-generating tool used enables us to have finer resolution at the scale of a few kilometers in fault zones and along plate boundaries in the area of interest. 1) This research is part of the EUROCORES TOPO-EUROPE, particularly of project TOPO-4D

  5. Reactive programming of simulations in physics

    NASA Astrophysics Data System (ADS)

    Boussinot, Frédéric; Monasse, Bernard; Susini, Jean-Ferdy

    2015-04-01

    We consider the Reactive Programming (RP) approach to simulate physical systems. The choice of RP is motivated by the fact that RP genuinely offers logical parallelism, instantaneously broadcast events, and dynamic creation/destruction of parallel components and events. To illustrate our approach, we consider the implementation of a system of Molecular Dynamics, in the context of Java with the Java3D library for 3D visualization.

  6. Small-Scale Hydroelectric Power Demonstration Project: reactivation of the Elk Rapids Hydroelectric Facility. Final technical and construction cost report

    SciTech Connect

    Not Available

    1985-05-01

    The Elk Rapids powerhouse dam is located on the Elk River channel in the Village of Elk Rapids, Michigan. Together with a small spillway structure located approximately 500 ft south of the dam, it constitutes the outlet to Lake Michigan for Elk Lake, Skegemog Lake, Torch Lake, Lake Bellaire, Clam Lake, and several smaller lakes. Power has been generated at the Elk Rapids site since the late nineteenth century, but the history of the present facility goes back to 1916 with the construction of the existing powerhouse dam by the Elk Rapids Iron Works Company. The facility was designed to contain four vertical-shaft generating units; however, only a single 270 hp Leffel type K unit was installed in 1916. In 1929, two additional Leffel units, rated 525 hp, were installed, and in 1930 a third 525 hp Leffel unit was added completely utilizing the capacity of the powerhouse and bringing the combined turbine capacity to 1845 hp.

  7. Thermonuclear runaways in nova outbursts. 2: Effect of strong, instantaneous, local fluctuations

    NASA Technical Reports Server (NTRS)

    Shankar, Anurag; Arnett, David

    1994-01-01

    In an attempt to understand the manner in which nova outbursts are initiated on the surface of a white dwarf, we investigate the effects fluctuations have on the evolution of a thermonuclear runaway. Fluctuations in temperature density, or the composition of material in the burning shell may arise due to the chaotic flow field generated by convection when it occurs, or by the accretion process itself. With the aid of two-dimensional reactive flow calculations, we consider cases where a strong fluctutation in temperature arises during the early, quiescent accretion phase or during the later, more dynamic, explosion phase. In all cases we find that an instantaneous, local temperature fluctuation causes the affected material to become Rayleigh-Taylor unstable. The rapid rise and subsequent expansion of matter immediately cools the hot blob, which prevents the lateral propagation of burning. This suggests that local temperature fluctuations do not play a significant role in directly initiating the runaway, especially during the early stages. However, they may provide an efficient mechanism of mixing core material into the envelope (thereby pre-enriching the fuel for subsequent episodes of explosive hydrogen burning) and of mixing substantial amounts of the radioactive nucleus N-13 into the surface layers, making novae potential gamma-ray sources. This suggests that it is the global not the local, evolution of the core-envelope interface to high temperatures which dominates the development of the runaway. We also present a possible new scenario for the initiation of nova outbursts based on our results.

  8. Instantaneous frequency measurement by in-fiber 0.5th order fractional differentiation

    NASA Astrophysics Data System (ADS)

    Poveda-Wong, L.; Carrascosa, A.; Cuadrado-Laborde, C.; Cruz, J. L.; Díez, A.; Andrés, M. V.

    2016-07-01

    We experimentally demonstrate the possibility to retrieve the instantaneous frequency profile of a given temporal light pulse by in-fiber fractional order differentiation of 0.5th-order. The signal's temporal instantaneous frequency profile is obtained by simple dividing two temporal intensity profiles, namely the intensities of the input and output pulses of a spectrally-shifted fractional order differentiation. The results are supported by the experimental measurement of the instantaneous frequency profile of a mode-locked laser.

  9. Toward reconciling instantaneous roadside measurements of light duty vehicle exhaust emissions with type approval driving cycles.

    PubMed

    Rhys-Tyler, Glyn A; Bell, Margaret C

    2012-10-01

    A method is proposed to relate essentially instantaneous roadside measurements of vehicle exhaust emissions, with emission results generated over a type approval driving cycle. An urban remote sensing data set collected in 2008 is used to define the dynamic relationship between vehicle specific power and exhaust emissions, across a range of vehicle ages, engine capacities, and fuel types. The New European Driving Cycle is synthesized from the remote sensing data using vehicle specific power to characterize engine load, and the results compared with official published emissions data from vehicle type approval tests over the same driving cycle. Mean carbon monoxide emissions from gasoline-powered cars ≤ 3 years old measured using remote sensing are found to be 1.3 times higher than published original type approval test values; this factor increases to 2.2 for cars 4-8 years old, and 6.4 for cars 9-12 years old. The corresponding factors for diesel cars are 1.1, 1.4, and 1.2, respectively. Results for nitric oxide, hydrocarbons, and particulate matter are also reported. The findings have potential implications for the design of traffic management interventions aimed at reducing emissions, fleet inspection and maintenance programs, and the specification of vehicle emission models. PMID:22894824

  10. Heart Instantaneous Frequency Based Estimation of HRV from Blood Pressure Waveforms

    NASA Astrophysics Data System (ADS)

    Lucena, Fausto; Barros, Allan Kardec; Takeuchi, Yoshinori; Ohnishi, Noboru

    The heart rate variability (HRV) is a measure based on the time position of the electrocardiogram (ECG) R-waves. There is a discussion whether or not we can obtain the HRV pattern from blood pressure (BP). In this paper, we propose a method for estimating HRV from a BP signal based on a HIF algorithm and carrying out experiments to compare BP as an alternative measurement of ECG to calculate HRV. Based on the hypotheses that ECG and BP have the same harmonic behavior, we model an alternative HRV signal using a nonlinear algorithm, called heart instantaneous frequency (HIF). It tracks the instantaneous frequency through a rough fundamental frequency using power spectral density (PSD). A novelty in this work is to use fundamental frequency instead of wave-peaks as a parameter to estimate and quantify beat-to-beat heart rate variability from BP waveforms. To verify how the estimate HRV signals derived from BP using HIF correlates to the standard gold measures, i.e. HRV derived from ECG, we use a traditional algorithm based on QRS detectors followed by thresholding to localize the R-wave time peak. The results show the following: 1) The spectral error caused by misestimation of time by R-peak detectors is demonstrated by an increase in high-frequency bands followed by the loss of time domain pattern. 2) The HIF was shown to be robust against noise and nuisances. 3) By using statistical methods and nonlinear analysis no difference between HIF derived from BP and HRV derived from ECG was observed.

  11. Assessing instantaneous synchrony of nonlinear nonstationary oscillators in the brain.

    PubMed

    Fine, Ananda S; Nicholls, David P; Mogul, David J

    2010-01-30

    Neuronal populations throughout the brain achieve levels of synchronous electrophysiological activity as a consequence of both normal brain function as well as during pathological states such as in epileptic seizures. Understanding this synchrony and being able to quantitatively assess the dynamics with which neuronal oscillators across the brain couple their activity is a critical component toward decoding such complex behavior. Commonly applied techniques to resolve relationships between oscillators typically make assumptions of linearity and stationarity that are likely not to be valid for complex neural signals. In this study, intracranial electroencephalographic activity was recorded bilaterally in both hippocampi and in anteromedial thalamus of rat under normal conditions and during hypersynchronous seizure activity induced by focal injection of the epileptogenic agent kainic acid. Nonlinear oscillators were first extracted using empirical mode decomposition. The technique of eigenvalue decomposition was used to assess global phase synchrony of the highest energy oscillators. The Hilbert analytical technique was then used to measure instantaneous phase synchrony of these oscillators as they evolved in time. To test the reliability of this method, we first applied it to a system of two coupled Rössler attractors under varying levels of coupling with small frequency mismatch. The application of these analytical techniques to intracranially recorded brain signals provides a means for assessing how complex oscillatory behavior in the brain evolves and changes during both normal activity and as a consequence of diseased states without making restrictive and possibly erroneous assumptions of the linearity and stationarity of the underlying oscillatory activity.

  12. Instantaneous fault frequencies estimation in roller bearings via wavelet structures

    NASA Astrophysics Data System (ADS)

    Rodopoulos, Konstantinos I.; Antoniadis, Ioannis A.

    2016-11-01

    The main target of the current paper is the effective application of the method proposed in "Antoniadis et al. (2014) [17], in roller bearings under variable speed. For this reason, roller bearing model with slip and real data coming from a test rig has been used. The method extracts useful information from a complicated signal where the overlap among the harmonics can raise up to 30%. According to the proposed method, a set of wavelet transforms of the signal is first obtained, using a structure of Complex Shifted Morlet Wavelets. The center frequencies and the bandwidths of the individual wavelets, as well as the number of wavelets used, are associated with the characteristic fault frequency and its harmonic components. In this way, a set of complex signals result in the time domain, equal to the number of the wavelets used. Then, the instantaneous frequencies of the signals are estimated by applying an appropriate subspace algorithm (as for e.g. ESPRIT), to the entire set of the resulting complex wavelet transforms, exploiting the corresponding subspace rotational invariance property of this set of complex signals. The iterative procedure brings up accurate results from complicated signals, separating the fault associated signal components. Also, the spectrograms of the processed signals confirm the ability to match excited areas with specific faults.

  13. Sensor for measuring instantaneous angle of attack of helicopter blades

    NASA Technical Reports Server (NTRS)

    Barna, P. S.

    1980-01-01

    Systematic investigations were performed on a variety of probes to determine their potential for possible application as sensors attached to helicopter blades to measure both the instantaneous angle of attack as well as the dynamic head during actual flight operations. After some preliminary considerations a sensor of essentially spherical shape, about 30 mm in diameter, was designed. The sensor was provided with three pressure ports, and it housed two pressure transducers required for sensing the prevailing pressures acting outside on the surface. The sensors were subsequently tested in the laboratory under a variety of flow conditions to determine their aerodynamic characteristics. Two series of tests were performed: in the first series the sensor was fixed in space while exposed to steady uniform flow, while in the second series the sensor was made to oscillate, thus simulating the cyclic pitch change of the helicopter blades. While the cyclic pitch frequencies were of about the same magnitude as encountered in flight, the flow velocities during tests fell well below those experienced in a rotating blade. The tests showed that the sensors performed satisfactorily under low subsonic flow conditions with frequencies not exceeding five Hz.

  14. Spectral and Instantaneous Flow Characteristics of Vascular Anastomoses.

    NASA Astrophysics Data System (ADS)

    Einav, Shmuel; Grad, Ygael

    1997-11-01

    A large percentage of patient implanted vascular bypass grafts fail early post- implantation. Biofluid factors as abnormal shear stresses and turbulence have been cited to promote graft failure. Previous studies were based on mean flow properties, while the pulsating flow field is affected by instantaneous and spectral distribution. Laminar to turbulent transition, flow separation, rotation and waves reflected from host artery leave characteristic spectral signature which escapes detection when only mean data is sampled. Our work was aimed into the time and frequency domain characteristics. Our in-vitro model consists of pulsating pump, transparent distensible graft tubes and variable anastomoses angles. Dimensions were based on in-vivo data. High speed Digital Particle Image Velocimetry (DPIV) was used to map the flow field and obtain the anastomoses spectral signature. High shear stress peaks and vortices were observed at the anastomosis toe. Flow reversal or separation was Womersley parameter dependent. The flow profile and spectra were dependent on graft angle and elasticity. Better host- graft match resulted in less flow disturbances and flatter spectral distribution. This can be translated in Doppler ultrasound or sound frequencies terms and thus potentially assist clinical observations. [DPIV Sample of Vascular Anastomosis]

  15. Cosmological perturbation theory, instantaneous gauges, and local inertial frames

    NASA Astrophysics Data System (ADS)

    Bičák, Jiří; Katz, Joseph; Lynden-Bell, Donald

    2007-09-01

    Linear perturbations of Friedmann-Robertson-Walker universes with any curvature and cosmological constant are studied in a general gauge without decomposition into harmonics. Desirable gauges are selected as those which embody best Mach’s principle: in these gauges local inertial frames can be determined instantaneously via the perturbed Einstein field equations from the distributions of energy and momentum in the universe. The inertial frames are identified by their “accelerations and rotations” with respect to the cosmological frames associated with the “Machian gauges.” In closed spherical universes, integral gauge conditions are imposed to eliminate motions generated by the conformal Killing vectors. The meaning of Traschen’s integral-constraint vectors is thus elucidated. For all three types of Friedmann-Robertson-Walker universes the Machian gauges admit much less residual freedom than the synchronous or generalized harmonic gauge. Mach’s principle is best exhibited in the Machian gauges in closed spherical universes. Independent of any Machian motivation, the general perturbation equations and discussion of gauges are useful for cosmological perturbation theory.

  16. Instantaneous BeiDou-GPS attitude determination: A performance analysis

    NASA Astrophysics Data System (ADS)

    Nadarajah, Nandakumaran; Teunissen, Peter J. G.; Raziq, Noor

    2014-09-01

    The advent of modernized and new global navigation satellite systems (GNSS) has enhanced the availability of satellite based positioning, navigation, and timing (PNT) solutions. Specifically, it increases redundancy and yields operational back-up or independence in case of failure or unavailability of one system. Among existing GNSS, the Chinese BeiDou system (BDS) is being developed and will consist of geostationary (GEO) satellites, inclined geosynchronous orbit (IGSO) satellites, and medium-Earth-orbit (MEO) satellites. In this contribution, a BeiDou-GPS robustness analysis is carried out for instantaneous, unaided attitude determination. Precise attitude determination using multiple GNSS antennas mounted on a platform relies on the successful resolution of the integer carrier phase ambiguities. The constrained Least-squares AMBiguity Decorrelation Adjustment (C-LAMBDA) method has been developed for the quadratically constrained GNSS compass model that incorporates the known baseline length. In this contribution the method is used to analyse the attitude determination performance when using the GPS and BeiDou systems. The attitude determination performance is evaluated using GPS/BeiDou data sets from a real data campaign in Australia spanning several days. The study includes the performance analyses of both stand-alone and mixed constellation (GPS/BeiDou) attitude estimation under various satellite deprived environments. We demonstrate and quantify the improved availability and accuracy of attitude determination using the combined constellation.

  17. Instantaneous Respiratory Estimation from Thoracic Impedance by Empirical Mode Decomposition

    PubMed Central

    Wang, Fu-Tai; Chan, Hsiao-Lung; Wang, Chun-Li; Jian, Hung-Ming; Lin, Sheng-Hsiung

    2015-01-01

    Impedance plethysmography provides a way to measure respiratory activity by sensing the change of thoracic impedance caused by inspiration and expiration. This measurement imposes little pressure on the body and uses the human body as the sensor, thereby reducing the need for adjustments as body position changes and making it suitable for long-term or ambulatory monitoring. The empirical mode decomposition (EMD) can decompose a signal into several intrinsic mode functions (IMFs) that disclose nonstationary components as well as stationary components and, similarly, capture respiratory episodes from thoracic impedance. However, upper-body movements usually produce motion artifacts that are not easily removed by digital filtering. Moreover, large motion artifacts disable the EMD to decompose respiratory components. In this paper, motion artifacts are detected and replaced by the data mirrored from the prior and the posterior before EMD processing. A novel intrinsic respiratory reconstruction index that considers both global and local properties of IMFs is proposed to define respiration-related IMFs for respiration reconstruction and instantaneous respiratory estimation. Based on the experiments performing a series of static and dynamic physical activates, our results showed the proposed method had higher cross correlations between respiratory frequencies estimated from thoracic impedance and those from oronasal airflow based on small window size compared to the Fourier transform-based method. PMID:26198231

  18. Development and evaluation of an instantaneous atmospheric corrosion rate monitor

    NASA Astrophysics Data System (ADS)

    Mansfeld, F.; Jeanjaquet, S. L.; Kendig, M. W.; Roe, D. K.

    1985-06-01

    A research program was carried out in which a new instantaneous atmospheric corrosion rate monitor (ACRM) was developed and evaluated, and equipment was constructed which will allow the use of many sensors in an economical way in outdoor exposures. In the first task, the ACRM was developed and tested in flow chambers in which relative humidity and gaseous and particulate pollutant levels can be controlled. Diurnal cycles and periods of rain were simulated. The effects of aerosols were studied. A computerized system was used for collection, storage, and analysis of the electrochemical data. In the second task, a relatively inexpensive electronics system for control of the ACRM and measurement of atmospheric corrosion rates was designed and built. In the third task, calibration of deterioration rates of various metallic and nonmetallic materials with the response of the ACRMs attached to these materials was carried out under controlled environmental conditions using the system developed in the second task. A Quality Assurance project plan was prepared with inputs from the Rockwell International Environmental Monitoring and Service Center and Quality Assurance System audits were performed.

  19. Limitations of rupture forecasting exposed by instantaneously triggered earthquake doublet

    NASA Astrophysics Data System (ADS)

    Nissen, E.; Elliott, J. R.; Sloan, R. A.; Craig, T. J.; Funning, G. J.; Hutko, A.; Parsons, B. E.; Wright, T. J.

    2016-04-01

    Earthquake hazard assessments and rupture forecasts are based on the potential length of seismic rupture and whether or not slip is arrested at fault segment boundaries. Such forecasts do not generally consider that one earthquake can trigger a second large event, near-instantaneously, at distances greater than a few kilometres. Here we present a geodetic and seismological analysis of a magnitude 7.1 intracontinental earthquake that occurred in Pakistan in 1997. We find that the earthquake, rather than a single event as hitherto assumed, was in fact an earthquake doublet: initial rupture on a shallow, blind reverse fault was followed just 19 s later by a second rupture on a separate reverse fault 50 km away. Slip on the second fault increased the total seismic moment by half, and doubled both the combined event duration and the area of maximum ground shaking. We infer that static Coulomb stresses at the initiation location of the second earthquake were probably reduced as a result of the first. Instead, we suggest that a dynamic triggering mechanism is likely, although the responsible seismic wave phase is unclear. Our results expose a flaw in earthquake rupture forecasts that disregard cascading, multiple-fault ruptures of this type.

  20. User-interactive electronic skin for instantaneous pressure visualization

    NASA Astrophysics Data System (ADS)

    Wang, Chuan; Hwang, David; Yu, Zhibin; Takei, Kuniharu; Park, Junwoo; Chen, Teresa; Ma, Biwu; Javey, Ali

    2013-10-01

    Electronic skin (e-skin) presents a network of mechanically flexible sensors that can conformally wrap irregular surfaces and spatially map and quantify various stimuli. Previous works on e-skin have focused on the optimization of pressure sensors interfaced with an electronic readout, whereas user interfaces based on a human-readable output were not explored. Here, we report the first user-interactive e-skin that not only spatially maps the applied pressure but also provides an instantaneous visual response through a built-in active-matrix organic light-emitting diode display with red, green and blue pixels. In this system, organic light-emitting diodes (OLEDs) are turned on locally where the surface is touched, and the intensity of the emitted light quantifies the magnitude of the applied pressure. This work represents a system-on-plastic demonstration where three distinct electronic components—thin-film transistor, pressure sensor and OLED arrays—are monolithically integrated over large areas on a single plastic substrate. The reported e-skin may find a wide range of applications in interactive input/control devices, smart wallpapers, robotics and medical/health monitoring devices.

  1. Instantaneous crack detection under changing operational and environmental variations

    NASA Astrophysics Data System (ADS)

    Kim, Seung Bum; Sohn, Hoon

    2007-04-01

    A new methodology of guided wave based nondestructive testing (NDT) is developed to detect crack damage in a thin metal structure without using prior baseline data or a predetermined decision boundary. In conventional guided wave based techniques, damage is often identified by comparing the "current" data obtained from a potentially damaged condition of a structure with the "past" baseline data collected at the pristine condition of the structure. However, it has been reported that this type of pattern comparison with the baseline data can lead to increased false alarms due to its susceptibility to varying operational and environmental conditions of the structure. To develop a more robust damage diagnosis technique, a new concept of NDT is conceived so that cracks can be detected even when the system being monitored is subjected to changing operational and environmental conditions. The proposed NDT technique utilizes the polarization characteristics of the piezoelectric wafers attached on the both sides of the thin metal structure. Crack formation creates Lamb wave mode conversion due to a sudden change in the thickness of the structure. Then, the proposed technique instantly detects the appearance of the crack by extracting this mode conversion from the measured Lamb waves, and the threshold value from damage classification is also obtained only from the current data set. Numerical and experimental results are presented to demonstrate the applicability of the proposed technique to instantaneous crack detection.

  2. Sodium Nitrate Induces Reactive Oxygen Species That Lower the Antioxidant Power, Damage the Membrane, and Alter Pathways of Glucose Metabolism in Human Erythrocytes.

    PubMed

    Ansari, Fariheen Aisha; Mahmood, Riaz

    2015-12-01

    Nitrate salts are widely used as food additives and nitrogenous fertilizers and are present as contaminants in drinking water supplies. The effect of different concentrations (1-15 mM) of sodium nitrate (NaNO3) on human erythrocytes was studied under in vitro conditions. Treatment of erythrocytes with NaNO3 resulted in increases in methemoglobin levels, lipid peroxidation, and protein oxidation and a decrease in glutathione content. There were changes in the activities of all major antioxidant defense enzymes, and the pathways of glucose metabolism were also affected. Increased generation of reactive oxygen species (ROS) took place while the antioxidant power was impaired. The osmotic fragility of cells was increased, and membrane-bound enzymes were greatly inhibited. All changes were statistically significant at a probability level of P < 0.05 at all concentrations of NaNO3 except the lowest (1 mM). Thus, NaNO3 generates ROS that cause significant damage to human erythrocytes and interfere in normal cellular pathways. PMID:26586154

  3. The effect of inductively-coupled-plasma reactive ion etching power on the etching rate and the surface roughness of a sapphire substrate.

    PubMed

    Chang, Chun-Ming; Shiao, Ming-Hua; Yang, Chin-Tien; Cheng, Chung-Ta; Hsueh, Wen-Jeng

    2014-10-01

    In this study, patterned sapphire substrates are fabricated using nanosphere lithography (NSL) and inductively-coupled-plasma reactive ion etching (ICP-RIE). Polystyrene nanospheres of approximately 600 nm diameter are self-assembled on c-plane sapphire substrates by spin-coating. The diameter of the polystyrene nanospheres is modified to adjust the etching mask pitch cycle using oxygen plasma in the ICP-RIE system. A nickel thin film mask of 100 nm thickness is deposited by electron-beam evaporation on a substrate covered with treated nanospheres. The sapphire substrate is then etched in an inductively coupled plasma system using BCl3/Ar gas, to fabricate a structure with a periodic sub-micron hole array with different sidewall intervals. The DC bias voltage, the sapphire etching rate, the surface roughness, are studied as a function of the ICP and the RF power. Different sub-micron hole arrays with spacing cycles of 89 nm, 139 nm and 167 nm are successfully fabricated on the sapphire substrate, using suitable etching parameters. PMID:25942926

  4. Preparation of diamond-like carbon films using reactive Ar/CH4 high power impulse magnetron sputtering system with negative pulse voltage source for substrate

    NASA Astrophysics Data System (ADS)

    Kimura, Takashi; Kamata, Hikaru

    2016-04-01

    Diamond-like carbon films were prepared using a reactive Ar/CH4 high-power impulse magnetron sputtering system with a negative pulse voltage source for the substrate, changing the CH4 fraction up to 15% in the total pressure range from 0.3 to 2 Pa. The magnitude of the negative pulse voltage for the substrate was also varied up to about 500 V. The hardness of films monotonically increased with increasing magnitude of the negative pulse voltage. The films with hardnesses between 16.5 and 23 GPa were prepared at total pressures less than 0.5 Pa and CH4 fractions less than 10% by applying an appropriate negative pulse voltage of 300-400 V. In X-ray photoelectron spectroscopy, the area ratio C-C sp3/(C-C sp2 + C-C sp3) in the C 1s core level was higher than 30% at pressures less than 0.5 Pa and CH4 fractions less than 15%. On the other hand, the films with hardnesses between 5 and 10 GPa were prepared with a relatively high growth rate at the partial pressures of CH4 higher than 0.1 Pa. However, the observation of the photoluminescence background in Raman spectroscopy indicated a relatively high hydrogen content.

  5. RelA-Mediated BECN1 Expression Is Required for Reactive Oxygen Species-Induced Autophagy in Oral Cancer Cells Exposed to Low-Power Laser Irradiation

    PubMed Central

    Wu, Chieh-Shan; Chen, Chien-Hsun; Wu, Sam; Chang, Hsueh-Wei; Kuo, Soong-Yu; Fu, Earl; Liu, Pei-Feng; Hsieh, Yao-Dung

    2016-01-01

    Low-power laser irradiation (LPLI) is a non-invasive and safe method for cancer treatment that alters a variety of physiological processes in the cells. Autophagy can play either a cytoprotective role or a detrimental role in cancer cells exposed to stress. The detailed mechanisms of autophagy and its role on cytotoxicity in oral cancer cells exposed to LPLI remain unclear. In this study, we showed that LPLI at 810 nm with energy density 60 J/cm2 increased the number of microtubule associated protein 1 light chain 3 (MAP1LC3) puncta and increased autophagic flux in oral cancer cells. Moreover, reactive oxygen species (ROS) production was induced, which increased RelA transcriptional activity and beclin 1 (BECN1) expression in oral cancer cells irradiated with LPLI. Furthermore, ROS scavenger or knockdown of RelA diminished LPLI-induced BECN1 expression and MAP1LC3-II conversion. In addition, pharmacological and genetic ablation of autophagy significantly enhanced the effects of LPLI-induced apoptosis in oral cancer cells. These results suggest that autophagy may be a resistant mechanism for LPLI-induced apoptosis in oral cancer cells. PMID:27632526

  6. RelA-Mediated BECN1 Expression Is Required for Reactive Oxygen Species-Induced Autophagy in Oral Cancer Cells Exposed to Low-Power Laser Irradiation.

    PubMed

    Shu, Chih-Wen; Chang, Hong-Tai; Wu, Chieh-Shan; Chen, Chien-Hsun; Wu, Sam; Chang, Hsueh-Wei; Kuo, Soong-Yu; Fu, Earl; Liu, Pei-Feng; Hsieh, Yao-Dung

    2016-01-01

    Low-power laser irradiation (LPLI) is a non-invasive and safe method for cancer treatment that alters a variety of physiological processes in the cells. Autophagy can play either a cytoprotective role or a detrimental role in cancer cells exposed to stress. The detailed mechanisms of autophagy and its role on cytotoxicity in oral cancer cells exposed to LPLI remain unclear. In this study, we showed that LPLI at 810 nm with energy density 60 J/cm2 increased the number of microtubule associated protein 1 light chain 3 (MAP1LC3) puncta and increased autophagic flux in oral cancer cells. Moreover, reactive oxygen species (ROS) production was induced, which increased RelA transcriptional activity and beclin 1 (BECN1) expression in oral cancer cells irradiated with LPLI. Furthermore, ROS scavenger or knockdown of RelA diminished LPLI-induced BECN1 expression and MAP1LC3-II conversion. In addition, pharmacological and genetic ablation of autophagy significantly enhanced the effects of LPLI-induced apoptosis in oral cancer cells. These results suggest that autophagy may be a resistant mechanism for LPLI-induced apoptosis in oral cancer cells. PMID:27632526

  7. Method for Visualizing Switching Patterns for a Matrix Converter Using Instantaneous Space Vector Diagrams

    NASA Astrophysics Data System (ADS)

    Haruna, Junnosuke; Itoh, Jun-Ichi

    This paper discusses the characteristics of a matrix converter determined using instantaneous space vector diagrams. Since 27 switching patterns are available for the matrix converter, 27 types of output voltages and input currents can be obtained. The instantaneous output voltages and input currents are plotted on an instantaneous output voltage diagram and an input current diagram, respectively. Then, the switching patterns of the matrix converter are visualized. From the instantaneous space vector diagrams, the output voltage ripple and input current ripple can be determined on the basis of the vector selected from among 27 instantaneous output voltage/input current vectors. In addition, the instantaneous space vector diagrams can be used to analyze the switching times. In this study, six different of control methods for the matrix converter are evaluated by using instantaneous space vector diagrams and the total harmonic distortion of the output voltage and input current. The results lead to the conclusion that characteristics of the matrix converter can be effectively evaluated using the instantaneous space vector diagrams.

  8. 16 CFR Appendix D4 to Part 305 - Water Heaters-Instantaneous-Gas

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Water Heaters-Instantaneous-Gas D4 Appendix...) Pt. 305, App. D4 Appendix D4 to Part 305—Water Heaters-Instantaneous-Gas Range Information CAPACITY FIRST HOUR RATING Range of Estimated Annual Operating Costs (Dollars/Year) Natural Gas ($/year) Low...

  9. 16 CFR Appendix D4 to Part 305 - Water Heaters-Instantaneous-Gas

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Water Heaters-Instantaneous-Gas D4 Appendix... CONGRESS RULE CONCERNING DISCLOSURES REGARDING ENERGY CONSUMPTION AND WATER USE OF CERTAIN HOME APPLIANCES...) Pt. 305, App. D4 Appendix D4 to Part 305—Water Heaters-Instantaneous-Gas Link to an...

  10. Lagged and instantaneous dynamical influences related to brain structural connectivity

    PubMed Central

    Alonso-Montes, Carmen; Diez, Ibai; Remaki, Lakhdar; Escudero, Iñaki; Mateos, Beatriz; Rosseel, Yves; Marinazzo, Daniele; Stramaglia, Sebastiano; Cortes, Jesus M.

    2015-01-01

    Contemporary neuroimaging methods can shed light on the basis of human neural and cognitive specializations, with important implications for neuroscience and medicine. Indeed, different MRI acquisitions provide different brain networks at the macroscale; whilst diffusion-weighted MRI (dMRI) provides a structural connectivity (SC) coincident with the bundles of parallel fibers between brain areas, functional MRI (fMRI) accounts for the variations in the blood-oxygenation-level-dependent T2* signal, providing functional connectivity (FC). Understanding the precise relation between FC and SC, that is, between brain dynamics and structure, is still a challenge for neuroscience. To investigate this problem, we acquired data at rest and built the corresponding SC (with matrix elements corresponding to the fiber number between brain areas) to be compared with FC connectivity matrices obtained by three different methods: directed dependencies by an exploratory version of structural equation modeling (eSEM), linear correlations (C) and partial correlations (PC). We also considered the possibility of using lagged correlations in time series; in particular, we compared a lagged version of eSEM and Granger causality (GC). Our results were two-fold: firstly, eSEM performance in correlating with SC was comparable to those obtained from C and PC, but eSEM (not C, nor PC) provides information about directionality of the functional interactions. Second, interactions on a time scale much smaller than the sampling time, captured by instantaneous connectivity methods, are much more related to SC than slow directed influences captured by the lagged analysis. Indeed the performance in correlating with SC was much worse for GC and for the lagged version of eSEM. We expect these results to supply further insights to the interplay between SC and functional patterns, an important issue in the study of brain physiology and function. PMID:26257682

  11. An Instantaneous Low-Cost Point-of-Care Anemia Detection Device

    PubMed Central

    Punter-Villagrasa, Jaime; Cid, Joan; Páez-Avilés, Cristina; Rodríguez-Villarreal, Ivón; Juanola-Feliu, Esteve; Colomer-Farrarons, Jordi; Miribel-Català, Pere Ll.

    2015-01-01

    We present a small, compact and portable device for point-of-care instantaneous early detection of anemia. The method used is based on direct hematocrit measurement from whole blood samples by means of impedance analysis. This device consists of a custom electronic instrumentation and a plug-and-play disposable sensor. The designed electronics rely on straightforward standards for low power consumption, resulting in a robust and low consumption device making it completely mobile with a long battery life. Another approach could be powering the system based on other solutions like indoor solar cells, or applying energy-harvesting solutions in order to remove the batteries. The sensing system is based on a disposable low-cost label-free three gold electrode commercial sensor for 50 μL blood samples. The device capability for anemia detection has been validated through 24 blood samples, obtained from four hospitalized patients at Hospital Clínic. As a result, the response, effectiveness and robustness of the portable point-of-care device to detect anemia has been proved with an accuracy error of 2.83% and a mean coefficient of variation of 2.57% without any particular case above 5%. PMID:25690552

  12. Instantaneous detection of spatial gradient errors in differential GNSS

    NASA Astrophysics Data System (ADS)

    Jing, Jing

    Global Navigation Satellite Systems (GNSS) have become a critical element of modern engineering and scientific applications. GPS is currently being used in the design of navigation systems for both civil and military aviation applications. Differential GPS carrier phase measurements between antennas provide a very precise measurement that is useful for these applications. In fact, ground infrastructure has already been implemented in the Ground Based Augmentation System (GBAS) to take advantage of these precise measurements for use in civil aviation. Furthermore, these antennas can also be used to detect and isolate certain signal-in-space (SIS) failures and anomalies that are hazardous to aviation applications, for example the ionospheric anomalies and ephemeris failures. This realization, in turn, has led to the development of numerous carrier-phase based monitors. One drawback of the majority of these monitors is that their performance within a given configuration is dependent on how antennas are paired to form double differences. In contrast, the null space monitor approach is developed to provide consistent detection performance regardless of how the antennas are paired which combines measurements from multiple, spatially separated ground antennas through a null space transformation. The instantaneous carrier phase monitor cannot detect all gradients due to the presence of integer ambiguities. These ambiguities cannot be resolved because the gradient magnitude is unknown a priori. Furthermore, it has been shown that the performance of such monitors is highly dependent on the reference antenna topology. The range of detectable gradients for all carrier phase monitors depends on two factors: the number of antennas and their configuration. Antenna configuration is often overlooked as a means to improve performance. and heuristic arguments typically prevail in the associated siting decisions. However. such heuristics do not provide the maximum detectable range of

  13. Instantaneous attribute profiling of GPR data using the HHT technique

    NASA Astrophysics Data System (ADS)

    Jeng*, Y.; Yu**, H.-M.; Chen, C.-S.

    2012-04-01

    * Corresponding author ** Presenting author The analysis of instantaneous attributes (IAs) is a useful tool for interpreting ground penetrating radar (GPR) data. However, the conventional Hilbert transform used for deriving the IAs is controversial because it cannot provide the full IAs of the data. The conventional method only leads to an apparent spectrogram. A newer analysis method, the Hilbert-Huang transform (HHT), consisting of empirical mode decomposition (EMD) and the Hilbert transform is applied in this study for seeking a better resolution of IAs. In this study, we decomposed the original GPR data into a series of intrinsic mode functions (IMFs) with ensemble empirical mode decomposition (EEMD), and then applied the Hilbert transform to generate the imaginary part of each IMF component. As a consequence, the IMF can be expressed in complex form after the Hilbert transform, and the IAs of each IMF component is obtained by simple trigonometry calculation and differentiation accordingly. With the aid of the EEMD technique, the Hilbert transform is well-behaved; therefore, it renders full IAs of each decomposed component as functions of time. We display the IAs of the GPR section in separate profiles to demonstrate the interpretation of their physical significance. A controlled experimental study was performed on a site of known buried targets to acquire sample data for testing this new method and establishing the basic data processing sequence. We also conducted a pseudo-3D GPR survey with 50 MHz antennas along the channel bed of the Chingshui River in Ilan County, northeastern Taiwan to collect real data for further evaluation. To compare the HHT with the conventional Hilbert transform, we applied both techniques to the GPR stacked section. The IAs are displayed in amplitude, phase, and frequency profiles. The residue resulting from the EEMD is normally excluded to remove the bias. The signal can further be enhanced by removing noisy components before

  14. Reactive sputtering of δ-ZrH{sub 2} thin films by high power impulse magnetron sputtering and direct current magnetron sputtering

    SciTech Connect

    Högberg, Hans Tengdelius, Lina; Eriksson, Fredrik; Broitman, Esteban; Lu, Jun; Jensen, Jens; Hultman, Lars; Samuelsson, Mattias

    2014-07-01

    Reactive sputtering by high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) of a Zr target in Ar/H{sub 2} plasmas was employed to deposit Zr-H films on Si(100) substrates, and with H content up to 61 at. % and O contents typically below 0.2 at. % as determined by elastic recoil detection analysis. X-ray photoelectron spectroscopy reveals a chemical shift of ∼0.7 eV to higher binding energies for the Zr-H films compared to pure Zr films, consistent with a charge transfer from Zr to H in a zirconium hydride. X-ray diffraction shows that the films are single-phase δ-ZrH{sub 2} (CaF{sub 2} type structure) at H content >∼55 at. % and pole figure measurements give a 111 preferred orientation for these films. Scanning electron microscopy cross-section images show a glasslike microstructure for the HiPIMS films, while the DCMS films are columnar. Nanoindentation yield hardness values of 5.5–7 GPa for the δ-ZrH{sub 2} films that is slightly harder than the ∼5 GPa determined for Zr films and with coefficients of friction in the range of 0.12–0.18 to compare with the range of 0.4–0.6 obtained for Zr films. Wear resistance testing show that phase-pure δ-ZrH{sub 2} films deposited by HiPIMS exhibit up to 50 times lower wear rate compared to those containing a secondary Zr phase. Four-point probe measurements give resistivity values in the range of ∼100–120 μΩ cm for the δ-ZrH{sub 2} films, which is slightly higher compared to Zr films with values in the range 70–80 μΩ cm.

  15. Instantaneous normal mode analysis for intermolecular and intramolecular vibrations of water from atomic point of view

    SciTech Connect

    Chen, Yu-Chun; Tang, Ping-Han; Wu, Ten-Ming

    2013-11-28

    By exploiting the instantaneous normal mode (INM) analysis for models of flexible molecules, we investigate intermolecular and intramolecular vibrations of water from the atomic point of view. With two flexible SPC/E models, our investigations include three aspects about their INM spectra, which are separated into the unstable, intermolecular, bending, and stretching bands. First, the O- and H-atom contributions in the four INM bands are calculated and their stable INM spectra are compared with the power spectra of the atomic velocity autocorrelation functions. The unstable and intermolecular bands of the flexible models are also compared with those of the SPC/E model of rigid molecules. Second, we formulate the inverse participation ratio (IPR) of the INMs, respectively, for the O- and H-atom and molecule. With the IPRs, the numbers of the three species participated in the INMs are estimated so that the localization characters of the INMs in each band are studied. Further, by the ratio of the IPR of the H atom to that of the O atom, we explore the number of involved OH bond per molecule participated in the INMs. Third, by classifying simulated molecules into subensembles according to the geometry of their local environments or their H-bond configurations, we examine the local-structure effects on the bending and stretching INM bands. All of our results are verified to be insensible to the definition of H-bond. Our conclusions about the intermolecular and intramolecular vibrations in water are given.

  16. Instantaneous normal mode analysis for intermolecular and intramolecular vibrations of water from atomic point of view.

    PubMed

    Chen, Yu-Chun; Tang, Ping-Han; Wu, Ten-Ming

    2013-11-28

    By exploiting the instantaneous normal mode (INM) analysis for models of flexible molecules, we investigate intermolecular and intramolecular vibrations of water from the atomic point of view. With two flexible SPC/E models, our investigations include three aspects about their INM spectra, which are separated into the unstable, intermolecular, bending, and stretching bands. First, the O- and H-atom contributions in the four INM bands are calculated and their stable INM spectra are compared with the power spectra of the atomic velocity autocorrelation functions. The unstable and intermolecular bands of the flexible models are also compared with those of the SPC/E model of rigid molecules. Second, we formulate the inverse participation ratio (IPR) of the INMs, respectively, for the O- and H-atom and molecule. With the IPRs, the numbers of the three species participated in the INMs are estimated so that the localization characters of the INMs in each band are studied. Further, by the ratio of the IPR of the H atom to that of the O atom, we explore the number of involved OH bond per molecule participated in the INMs. Third, by classifying simulated molecules into subensembles according to the geometry of their local environments or their H-bond configurations, we examine the local-structure effects on the bending and stretching INM bands. All of our results are verified to be insensible to the definition of H-bond. Our conclusions about the intermolecular and intramolecular vibrations in water are given.

  17. Instantaneous normal mode analysis for intermolecular and intramolecular vibrations of water from atomic point of view

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Chun; Tang, Ping-Han; Wu, Ten-Ming

    2013-11-01

    By exploiting the instantaneous normal mode (INM) analysis for models of flexible molecules, we investigate intermolecular and intramolecular vibrations of water from the atomic point of view. With two flexible SPC/E models, our investigations include three aspects about their INM spectra, which are separated into the unstable, intermolecular, bending, and stretching bands. First, the O- and H-atom contributions in the four INM bands are calculated and their stable INM spectra are compared with the power spectra of the atomic velocity autocorrelation functions. The unstable and intermolecular bands of the flexible models are also compared with those of the SPC/E model of rigid molecules. Second, we formulate the inverse participation ratio (IPR) of the INMs, respectively, for the O- and H-atom and molecule. With the IPRs, the numbers of the three species participated in the INMs are estimated so that the localization characters of the INMs in each band are studied. Further, by the ratio of the IPR of the H atom to that of the O atom, we explore the number of involved OH bond per molecule participated in the INMs. Third, by classifying simulated molecules into subensembles according to the geometry of their local environments or their H-bond configurations, we examine the local-structure effects on the bending and stretching INM bands. All of our results are verified to be insensible to the definition of H-bond. Our conclusions about the intermolecular and intramolecular vibrations in water are given.

  18. Method for preparing hydride configurations and reactive metal surfaces

    DOEpatents

    Silver, G.L.

    1984-05-18

    A method for preparing reactive metal surfaces, particularly uranium surfaces is disclosed, whereby the metal is immediately reactive to hydrogen gas at room temperature and low pressure. The metal surfaces are first pretreated by exposure to an acid which forms an adherent hydride-bearing composition on the metal surface. Subsequent heating of the pretreated metal at a temperature sufficient to decompose the hydride coating in vacuum or inert gas renders the metal surface instantaneously reactive to hydrogen gas at room temperature and low pressure.

  19. Pulse-by-pulse method to characterize partially coherent pulse propagation in instantaneous nonlinear media.

    PubMed

    Lajunen, Hanna; Torres-Company, Víctor; Lancis, Jesús; Silvestre, Enrique; Andrès, Pedro

    2010-07-01

    We propose a numerical method for analyzing extensively the evolution of the coherence functions of nonstationary optical pulses in dispersive, instantaneous nonlinear Kerr media. Our approach deals with the individual propagation of samples from a properly selected ensemble that reproduces the coherence properties of the input pulsed light. In contrast to the usual strategy assuming Gaussian statistics, our numerical algorithm allows us to model the propagation of arbitrary partially coherent pulses in media with strong and instantaneous nonlinearities. PMID:20639984

  20. Study of Microstructure and Transient, Instantaneous Current in Different Excitations During Silicon Micromachining

    NASA Astrophysics Data System (ADS)

    Kulkarni, A. V.; Jain, V. K.; Misra, K. A.

    2012-09-01

    Study of transient, instantaneous current during silicon micromachining using electrochemical spark process is carried out. Voltage excitation of three kinds namely, dc, Half wave rectified and ac are used to carve the micro channels. The transient and instantaneous process current is measured online and analyzed for each excitation. Micromachining and the surface topography results are presented. The transient current reveals the mechanism of the spark formation and explains the inherent process stages.

  1. Skylab reactivation mission report

    NASA Technical Reports Server (NTRS)

    Chubb, W. B.

    1980-01-01

    On July 11, 1979, Skylab impacted the Earth's surface. The debris dispersion area stretched from the South Eastern Indian Ocean across a sparsely populated section of Western Australia. The events leading to the reentry of Skylab are discussed and a final assessment of the Skylab debris impact footprint is presented. Also included are detailed evaluations of the various Skylab systems that were reactivated when control of Skylab was regained in mid-1978 after having been powered down since February 4, 1974.

  2. Measurement of instantaneous viscoelastic properties by impedance-frequency curve of the ventricle.

    PubMed

    Koiwa, Y; Hashiguchi, R; Ohyama, T; Isoyama, S; Satoh, S; Suzuki, H; Takishima, T

    1986-04-01

    We developed a method for estimating the instantaneous viscoelastic properties of the left ventricle (LV). This impedance-curve method is based on the instantaneous impedance-frequency curve of the left ventricle generated by a rapidly oscillating mechanical impulse applied to the epicardial surface of the heart. The theoretical basis of the method and experimentally obtained instantaneous impedance-frequency curves were examined to evaluate the validity of our basic assumptions. Using these impedance-curve data, we calculated the instantaneous viscoelastic properties of the LV during the cardiac cycle. The impedance curve shows a configuration that is almost the same as the theoretical curve based on the assumption that an RCL (R, resistor; C, capacitor; L, inductor) parallel circuit is the electrical analog for the LV. The impedance curve varied moment by moment during the development of instantaneous LV pressure. The elastic and viscous coefficients, calculated from the impedance curve, increased with increase of LV pressure. We concluded that the impedance-curve method can delineate the instantaneous viscoelastic properties of the ventricle (especially of the ventricular myocardium).

  3. Cross-correlation of instantaneous phase increments in pressure-flow fluctuations: Applications to cerebral autoregulation

    PubMed Central

    Chen, Zhi; Hu, Kun; Stanley, H. Eugene; Novak, Vera; Ivanov, Plamen Ch.

    2007-01-01

    We investigate the relationship between the blood flow velocities (BFV) in the middle cerebral arteries and beat-to-beat blood pressure (BP) recorded from a finger in healthy and post-stroke subjects during the quasisteady state after perturbation for four different physiologic conditions: supine rest, head-up tilt, hyperventilation, and CO2 rebreathing in upright position. To evaluate whether instantaneous BP changes in the steady state are coupled with instantaneous changes in the BFV, we compare dynamical patterns in the instantaneous phases of these signals, obtained from the Hilbert transform, as a function of time. We find that in post-stroke subjects the instantaneous phase increments of BP and BFV exhibit well-pronounced patterns that remain stable in time for all four physiologic conditions, while in healthy subjects these patterns are different, less pronounced, and more variable. We propose an approach based on the cross-correlation of the instantaneous phase increments to quantify the coupling between BP and BFV signals. We find that the maximum correlation strength is different for the two groups and for the different conditions. For healthy subjects the amplitude of the cross-correlation between the instantaneous phase increments of BP and BFV is small and attenuates within 3−5 heartbeats. In contrast, for post-stroke subjects, this amplitude is significantly larger and cross-correlations persist up to 20 heartbeats. Further, we show that the instantaneous phase increments of BP and BFV are cross-correlated even within a single heartbeat cycle. We compare the results of our approach with three complementary methods: direct BP-BFV cross-correlation, transfer function analysis, and phase synchronization analysis. Our findings provide insight into the mechanism of cerebral vascular control in healthy subjects, suggesting that this control mechanism may involve rapid adjustments (within a heartbeat) of the cerebral vessels, so that BFV remains steady in

  4. Reactivity effects in VVER-1000 of the third unit of the kalinin nuclear power plant at physical start-up. Computations in ShIPR intellectual code system with library of two-group cross sections generated by UNK code

    SciTech Connect

    Zizin, M. N.; Zimin, V. G.; Zizina, S. N. Kryakvin, L. V.; Pitilimov, V. A.; Tereshonok, V. A.

    2010-12-15

    The ShIPR intellectual code system for mathematical simulation of nuclear reactors includes a set of computing modules implementing the preparation of macro cross sections on the basis of the two-group library of neutron-physics cross sections obtained for the SKETCH-N nodal code. This library is created by using the UNK code for 3D diffusion computation of first VVER-1000 fuel loadings. Computation of neutron fields in the ShIPR system is performed using the DP3 code in the two-group diffusion approximation in 3D triangular geometry. The efficiency of all groups of control rods for the first fuel loading of the third unit of the Kalinin Nuclear Power Plant is computed. The temperature, barometric, and density effects of reactivity as well as the reactivity coefficient due to the concentration of boric acid in the reactor were computed additionally. Results of computations are compared with the experiment.

  5. Reactivity effects in VVER-1000 of the third unit of the kalinin nuclear power plant at physical start-up. Computations in ShIPR intellectual code system with library of two-group cross sections generated by UNK code

    NASA Astrophysics Data System (ADS)

    Zizin, M. N.; Zimin, V. G.; Zizina, S. N.; Kryakvin, L. V.; Pitilimov, V. A.; Tereshonok, V. A.

    2010-12-01

    The ShIPR intellectual code system for mathematical simulation of nuclear reactors includes a set of computing modules implementing the preparation of macro cross sections on the basis of the two-group library of neutron-physics cross sections obtained for the SKETCH-N nodal code. This library is created by using the UNK code for 3D diffusion computation of first VVER-1000 fuel loadings. Computation of neutron fields in the ShIPR system is performed using the DP3 code in the two-group diffusion approximation in 3D triangular geometry. The efficiency of all groups of control rods for the first fuel loading of the third unit of the Kalinin Nuclear Power Plant is computed. The temperature, barometric, and density effects of reactivity as well as the reactivity coefficient due to the concentration of boric acid in the reactor were computed additionally. Results of computations are compared with the experiment.

  6. Fuel Temperature Coefficient of Reactivity

    SciTech Connect

    Loewe, W.E.

    2001-07-31

    A method for measuring the fuel temperature coefficient of reactivity in a heterogeneous nuclear reactor is presented. The method, which is used during normal operation, requires that calibrated control rods be oscillated in a special way at a high reactor power level. The value of the fuel temperature coefficient of reactivity is found from the measured flux responses to these oscillations. Application of the method in a Savannah River reactor charged with natural uranium is discussed.

  7. Combining the Power of Irmpd with Ion-Molecule Reactions: the Structure and Reactivity of Radical Ions of Cysteine and its Derivatives

    NASA Astrophysics Data System (ADS)

    Lesslie, Michael; Osburn, Sandra; Berden, Giel; Oomens, J.; Ryzhov, Victor

    2015-06-01

    Most of the work on peptide radical cations has involved protons as the source of charge. Nonetheless, using metal ions as charge sources often offers advantages like stabilization of the structure via multidentate coordination and the elimination of the "mobile proton". Moreover, characterization of metal-bound amino acids is of general interest as the interaction of peptide side chains with metal ions in biological systems is known to occur extensively. In the current study, we generate thiyl radicals of cysteine and homocysteine in the gas phase complexed to alkali metal ions. Subsequently, we utilize infrared multiple-photon dissociation (IRMPD) and ion-molecule reactions (IMR) to characterize the structure and reactivity of these radical ions. Our group has worked extensively with the cysteine-based radical cations and anions, characterizing the gas-phase reactivity and rearrangement of the amino acid and several of its derivatives. In a continuation of this work, we are perusing the effects of metal ions as the charge bearing species on the reactivity of the sulfur radical. Our S-nitroso chemistry can easily be used in conjunction with metal ion coordination to produce initial S-based radicals in peptide radical-metal ion complexes. In all cases we have been able to achieve radical formation with significant yield to study reactivity. Ion-molecule reactions of metallated radicals with allyl iodide, dimethyl disulfide, and allyl bromide have all shown decreasing reactivity going down group 1A. Recently, we determined the experimental IR spectra for the homocysteine radical cation with Li+, Na+, and K+ as the charge bearing species at the FELIX facility. For comparison, the protonated IR spectrum of homocysteine has previously been obtained by our group. A preliminary match of the IR spectra has been confirmed. Finally, calculations are underway to determine the bond distances of all the metal adduct structures.

  8. Application of Hilbert-Huang transform based instantaneous frequency to seismic reflection data

    NASA Astrophysics Data System (ADS)

    Zhou, Yanhui; Chen, Wenchao; Gao, Jinghuai; He, Yongqiang

    2012-07-01

    Empirical mode decomposition (EMD) is designed to decompose non-stationary, nonlinear data into a series of intrinsic mode functions (IMFs) adaptively. This procedure is automatic, data-driven and time-variant. And then a Hilbert transform is applied to these IMFs. The combination of EMD with a Hilbert transform is known as Hilbert-Huang transform (HHT). HHT can be used to calculate meaningful multi-resolution instantaneous frequency (HHT based instantaneous frequency). Currently, the application of EMD and HHT to seismic data is performed mainly for noise attenuation. In this paper, we demonstrate new insights of EMD and HHT to seismic data analysis. We first extend the research of Flandrin et al. and analyze how EMD behaves on a Gaussian band-pass signal; we then employ HHT based instantaneous frequency on wedge model and real seismic data to delineate thickness variations. Numerical examples of Gaussian band-pass noise indicate that EMD acts as an adaptive, multi-band overlapping filter bank. The analysis of a wedge model and 2D real seismic data illustrates that HHT based instantaneous frequency is more effective than conventional Hilbert transform based instantaneous frequency in delineating the thickness variation of seismic thin bed.

  9. What Is Reactive Arthritis?

    MedlinePlus

    ... Arthritis PDF Version Size: 69 KB November 2014 What is Reactive Arthritis? Fast Facts: An Easy-to- ... Information About Reactive Arthritis and Other Related Conditions What Causes Reactive Arthritis? Sometimes, reactive arthritis is set ...

  10. Engine combustion control via fuel reactivity stratification

    DOEpatents

    Reitz, Rolf Deneys; Hanson, Reed M; Splitter, Derek A; Kokjohn, Sage L

    2013-12-31

    A compression ignition engine uses two or more fuel charges having two or more reactivities to control the timing and duration of combustion. In a preferred implementation, a lower-reactivity fuel charge is injected or otherwise introduced into the combustion chamber, preferably sufficiently early that it becomes at least substantially homogeneously dispersed within the chamber before a subsequent injection is made. One or more subsequent injections of higher-reactivity fuel charges are then made, and these preferably distribute the higher-reactivity matter within the lower-reactivity chamber space such that combustion begins in the higher-reactivity regions, and with the lower-reactivity regions following thereafter. By appropriately choose the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot).

  11. Engine combustion control via fuel reactivity stratification

    DOEpatents

    Reitz, Rolf Deneys; Hanson, Reed M.; Splitter, Derek A.; Kokjohn, Sage L.

    2015-07-14

    A compression ignition engine uses two or more fuel charges having two or more reactivities to control the timing and duration of combustion. In a preferred implementation, a lower-reactivity fuel charge is injected or otherwise introduced into the combustion chamber, preferably sufficiently early that it becomes at least substantially homogeneously dispersed within the chamber before a subsequent injection is made. One or more subsequent injections of higher-reactivity fuel charges are then made, and these preferably distribute the higher-reactivity matter within the lower-reactivity chamber space such that combustion begins in the higher-reactivity regions, and with the lower-reactivity regions following thereafter. By appropriately choosing the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot).

  12. Engine combustion control via fuel reactivity stratification

    DOEpatents

    Reitz, Rolf Deneys; Hanson, Reed M.; Splitter, Derek A.; Kokjohn, Sage L.

    2016-06-28

    A compression ignition engine uses two or more fuel charges having two or more reactivities to control the timing and duration of combustion. In a preferred implementation, a lower-reactivity fuel charge is injected or otherwise introduced into the combustion chamber, preferably sufficiently early that it becomes at least substantially homogeneously dispersed within the chamber before a subsequent injection is made. One or more subsequent injections of higher-reactivity fuel charges are then made, and these preferably distribute the higher-reactivity matter within the lower-reactivity chamber space such that combustion begins in the higher-reactivity regions, and with the lower-reactivity regions following thereafter. By appropriately choosing the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot).

  13. Thermodynamics of iodide adsorption at the instantaneous air-water interface

    NASA Astrophysics Data System (ADS)

    Stern, Abraham C.; Baer, Marcel D.; Mundy, Christopher J.; Tobias, Douglas J.

    2013-03-01

    We performed molecular dynamics simulations using both polarizable and non-polarizable force fields to study the adsorption of iodide to the air-water interface. A novel aspect of our analysis is that the progress of ion adsorption is measured as the distance from the instantaneous interface, which is defined by a coarse-graining scheme proposed recently by Willard and Chandler ["Instantaneous liquid interfaces," J. Phys. Chem. B 114, 1954-1958 (2010), 10.1021/jp909219k]. Referring structural and thermodynamic quantities to the instantaneous interface unmasks molecular-scale details that are obscured by thermal fluctuations when the same quantities are referred to an average measure of the position of the interface, such as the Gibbs dividing surface. Our results suggest that an ion adsorbed at the interface resides primarily in the topmost water layer, and the interfacial location of the ion is favored by enthalpy and opposed by entropy.

  14. Instantaneous Click Chemistry by a Copper-Containing Polymeric-Membrane-Installed Microflow Catalytic Reactor.

    PubMed

    Yamada, Yoichi M A; Ohno, Aya; Sato, Takuma; Uozumi, Yasuhiro

    2015-11-23

    The copper(I)-catalyzed Huisgen cycloaddition (azide-alkyne cycloaddition) is an important reaction in click chemistry that ideally proceeds instantaneously. An instantaneous Huisgen cycloaddition has been developed that uses a novel catalytic dinuclear copper complex-containing polymeric membrane-installed microflow device. A polymeric membranous copper catalyst was prepared from poly(4-vinylpyridine), copper(II) sulfate, sodium chloride, and sodium ascorbate at the interface of two laminar flows inside microchannels. Elucidation of the structure by XANES, EXAFS, and elemental analysis, as well as second-order Møller-Plesset perturbation theory (MP2) calculations and density functional theory (DFT) calculations assigned the local structure near Cu as a μ-chloro dinuclear Cu(I) complex. The microflow device promotes the instantaneous click reaction of a variety of alkynes and organic azides to afford the corresponding triazoles in quantitative yield. PMID:26439220

  15. Summary of U.S. Geological Survey on-line instantaneous fluvial sediment and ancillary data

    USGS Publications Warehouse

    Turcios, Lisa M.; Gray, John R.; Ledford, Annette L.

    2000-01-01

    Instantaneous fluvial sediment data, in addition to other instantaneous water-quality and ancillary data collected by the U.S. Geological Survey (USGS), are available on-line through the National Water Information System World Wide Web (NWISWeb) water-quality data base at http://waterdata.usgs.gov/nwis/qwdata. The NWISWeb water-quality data base was populated and is periodically refreshed from electronic files maintained by individual USGS District offices across the United States and Puerto Rico. It represents the single largest repository of USGS electronic instantaneous-value suspended-sediment, bedload, and bed-material data. These Web pages provide a summary of fluvial-sediment data by State, and by USGS station number retrieved from the then-under-construction NWISWeb data base on January 13, 2000. The meta data can be accessed by following the links at the bottom of this Web page.

  16. Assessing Dynamic Spectral Causality by Lagged Adaptive Directed Transfer Function and Instantaneous Effect Factor

    PubMed Central

    Xu, Haojie; Lu, Yunfeng; Zhu, Shanan

    2014-01-01

    It is of significance to assess the dynamic spectral causality among physiological signals. Several practical estimators adapted from spectral Granger causality have been exploited to track dynamic causality based on the framework of time-varying multivariate autoregressive (tvMVAR) models. The non-zero covariance of the model’s residuals has been used to describe the instantaneous effect phenomenon in some causality estimators. However, for the situations with Gaussian residuals in some autoregressive models, it is challenging to distinguish the directed instantaneous causality if the sufficient prior information about the “causal ordering” is missing. Here, we propose a new algorithm to assess the time-varying causal ordering of tvMVAR model under the assumption that the signals follow the same acyclic causal ordering for all time lags and to estimate the instantaneous effect factor (IEF) value in order to track the dynamic directed instantaneous connectivity. The time-lagged adaptive directed transfer function (ADTF) is also estimated to assess the lagged causality after removing the instantaneous effect. In the present study, we firstly investigated the performance of the causal-ordering estimation algorithm and the accuracy of IEF value. Then, we presented the results of IEF and time-lagged ADTF method by comparing with the conventional ADTF method through simulations of various propagation models. Statistical analysis results suggest that the new algorithm could accurately estimate the causal ordering and give a good estimation of the IEF values in the Gaussian residual conditions. Meanwhile, the time-lagged ADTF approach is also more accurate in estimating the time-lagged dynamic interactions in a complex nervous system after extracting the instantaneous effect. In addition to the simulation studies, we applied the proposed method to estimate the dynamic spectral causality on real visual evoked potential (VEP) data in a human subject. Its usefulness in

  17. Experimental study on instantaneous thrust and lift of two plunging wings in tandem

    NASA Astrophysics Data System (ADS)

    Gong, Wu Qi; Jia, Bo Bo; Xi, Guang

    2016-01-01

    Two tandem wings undergoing a two-dimensional sinusoidal plunging motion are studied in a low Reynolds number water tunnel. The influence of the phase angle and leading-edge vortex (LEV) on the peak value of the instantaneous thrust and lift is studied. The instantaneous lift and thrust are measured by a force sensor; the velocity and vorticity fields are captured by digital particle image velocimetry. For the forewing, noticeable differences at various phase angles are found in the peak value of the instantaneous lift and thrust rather than in their minimum value. The LEV of the hindwing increased the maximum effective angle of attack of the forewing and enhanced the jet-like flow behind the forewing, which accounts for the increase in peak value. For the hindwing, the phase angle determines the sign of the forewing-shed LEV when the hindwing encounters this LEV. If the forewing-shed LEV before the leading edge of the hindwing has the opposite sense of rotation as the LEV of the hindwing, the velocity of the flow on the windward side of the hindwing increases, resulting in high instantaneous thrust and lift. If the two LEVs have the same sense of rotation, the forewing-shed LEV hinders the growth of the hindwing LEV because of the small effective angle of attack, leading to low instantaneous thrust and lift. Non-circulatory forces on the wings are calculated according to a potential flow model. Results show that the non-circulatory force has important effects on the peak value and symmetry of the instantaneous lift and thrust curves.

  18. Overestimating Fish Counts by Non-Instantaneous Visual Censuses: Consequences for Population and Community Descriptions

    PubMed Central

    Ward-Paige, Christine; Mills Flemming, Joanna; Lotze, Heike K.

    2010-01-01

    Background Increasingly, underwater visual censuses (UVC) are used to assess fish populations. Several studies have demonstrated the effectiveness of protected areas for increasing fish abundance or provided insight into the natural abundance and structure of reef fish communities in remote areas. Recently, high apex predator densities (>100,000 individuals·km−2) and biomasses (>4 tonnes·ha−1) have been reported for some remote islands suggesting the occurrence of inverted trophic biomass pyramids. However, few studies have critically evaluated the methods used for sampling conspicuous and highly mobile fish such as sharks. Ideally, UVC are done instantaneously, however, researchers often count animals that enter the survey area after the survey has started, thus performing non-instantaneous UVC. Methodology/Principal Findings We developed a simulation model to evaluate counts obtained by divers deploying non-instantaneous belt-transect and stationary-point-count techniques. We assessed how fish speed and survey procedure (visibility, diver speed, survey time and dimensions) affect observed fish counts. Results indicate that the bias caused by fish speed alone is huge, while survey procedures had varying effects. Because the fastest fishes tend to be the largest, the bias would have significant implications on their biomass contribution. Therefore, caution is needed when describing abundance, biomass, and community structure based on non-instantaneous UVC, especially for highly mobile species such as sharks. Conclusions/Significance Based on our results, we urge that published literature state explicitly whether instantaneous counts were made and that survey procedures be accounted for when non-instantaneous counts are used. Using published density and biomass values of communities that include sharks we explore the effect of this bias and suggest that further investigation may be needed to determine pristine shark abundances and the existence of inverted

  19. The instantaneous rate dependence in low temperature laboratory rock friction and rock deformation experiments

    USGS Publications Warehouse

    Beeler, N.M.; Tullis, T.E.; Kronenberg, A.K.; Reinen, L.A.

    2007-01-01

    Earthquake occurrence probabilities that account for stress transfer and time-dependent failure depend on the product of the effective normal stress and a lab-derived dimensionless coefficient a. This coefficient describes the instantaneous dependence of fault strength on deformation rate, and determines the duration of precursory slip. Although an instantaneous rate dependence is observed for fracture, friction, crack growth, and low temperature plasticity in laboratory experiments, the physical origin of this effect during earthquake faulting is obscure. We examine this rate dependence in laboratory experiments on different rock types using a normalization scheme modified from one proposed by Tullis and Weeks [1987]. We compare the instantaneous rate dependence in rock friction with rate dependence measurements from higher temperature dislocation glide experiments. The same normalization scheme is used to compare rate dependence in friction to rock fracture and to low-temperature crack growth tests. For particular weak phyllosilicate minerals, the instantaneous friction rate dependence is consistent with dislocation glide. In intact rock failure tests, for each rock type considered, the instantaneous rate dependence is the same size as for friction, suggesting a common physical origin. During subcritical crack growth in strong quartzofeldspathic and carbonate rock where glide is not possible, the instantaneous rate dependence measured during failure or creep tests at high stress has long been thought to be due to crack growth; however, direct comparison between crack growth and friction tests shows poor agreement. The crack growth rate dependence appears to be higher than the rate dependence of friction and fracture by a factor of two to three for all rock types considered. Copyright 2007 by the American Geophysical Union.

  20. Precise measurement of instantaneous volume of eccrine sweat gland in mental sweating by optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Sugawa, Yoshihiko; Fukuda, Akihiro; Ohmi, Masato

    2015-03-01

    We have demonstrated dynamic analysis of the physiological function of eccrine sweat glands underneath skin surface by optical coherence tomography (OCT). We propose a method for extraction of the target eccrine sweat gland by use of the connected component extraction process and the adaptive threshold method, where the en-face OCT images are constructed by the SS-OCT. Furthermore, we demonstrate precise measurement of instantaneous volume of the sweat gland in response to the external stimulus. The dynamic change of instantaneous volume of eccrine sweat gland in mental sweating is performed by this method during the period of 300 sec with the frame intervals of 3.23 sec.

  1. A 32-GHz reflected-wave maser amplifier with wide instantaneous bandwidth

    NASA Technical Reports Server (NTRS)

    Shell, J.; Neff, D.

    1988-01-01

    An eight stage, 32 GHz reflected wave ruby maser was built. The maser operates in a 3 watt closed cycle refrigerator at 4.5 K and is capable of 21 dB of net gain with an instantaneous bandwidth of 400 MHz. The input noise temperature referred to the room temperature flange is approximately 21 K.

  2. Inhomogeneous Point-Processes to Instantaneously Assess Affective Haptic Perception through Heartbeat Dynamics Information

    NASA Astrophysics Data System (ADS)

    Valenza, G.; Greco, A.; Citi, L.; Bianchi, M.; Barbieri, R.; Scilingo, E. P.

    2016-06-01

    This study proposes the application of a comprehensive signal processing framework, based on inhomogeneous point-process models of heartbeat dynamics, to instantaneously assess affective haptic perception using electrocardiogram-derived information exclusively. The framework relies on inverse-Gaussian point-processes with Laguerre expansion of the nonlinear Wiener-Volterra kernels, accounting for the long-term information given by the past heartbeat events. Up to cubic-order nonlinearities allow for an instantaneous estimation of the dynamic spectrum and bispectrum of the considered cardiovascular dynamics, as well as for instantaneous measures of complexity, through Lyapunov exponents and entropy. Short-term caress-like stimuli were administered for 4.3–25 seconds on the forearms of 32 healthy volunteers (16 females) through a wearable haptic device, by selectively superimposing two levels of force, 2 N and 6 N, and two levels of velocity, 9.4 mm/s and 65 mm/s. Results demonstrated that our instantaneous linear and nonlinear features were able to finely characterize the affective haptic perception, with a recognition accuracy of 69.79% along the force dimension, and 81.25% along the velocity dimension.

  3. Inhomogeneous Point-Processes to Instantaneously Assess Affective Haptic Perception through Heartbeat Dynamics Information

    NASA Astrophysics Data System (ADS)

    Valenza, G.; Greco, A.; Citi, L.; Bianchi, M.; Barbieri, R.; Scilingo, E. P.

    2016-06-01

    This study proposes the application of a comprehensive signal processing framework, based on inhomogeneous point-process models of heartbeat dynamics, to instantaneously assess affective haptic perception using electrocardiogram-derived information exclusively. The framework relies on inverse-Gaussian point-processes with Laguerre expansion of the nonlinear Wiener-Volterra kernels, accounting for the long-term information given by the past heartbeat events. Up to cubic-order nonlinearities allow for an instantaneous estimation of the dynamic spectrum and bispectrum of the considered cardiovascular dynamics, as well as for instantaneous measures of complexity, through Lyapunov exponents and entropy. Short-term caress-like stimuli were administered for 4.3-25 seconds on the forearms of 32 healthy volunteers (16 females) through a wearable haptic device, by selectively superimposing two levels of force, 2 N and 6 N, and two levels of velocity, 9.4 mm/s and 65 mm/s. Results demonstrated that our instantaneous linear and nonlinear features were able to finely characterize the affective haptic perception, with a recognition accuracy of 69.79% along the force dimension, and 81.25% along the velocity dimension.

  4. Vibrotactile discrimination in the rat whisker system is based on neuronal coding of instantaneous kinematic cues.

    PubMed

    Waiblinger, Christian; Brugger, Dominik; Schwarz, Cornelius

    2015-04-01

    Which physical parameter of vibrissa deflections is extracted by the rodent tactile system for discrimination? Particularly, it remains unclear whether perception has access to instantaneous kinematic parameters (i.e., the details of the trajectory) or relies on temporally integration of the movement trajectory such as frequency (e.g., spectral information) and intensity (e.g., mean speed). Here, we use a novel detection of change paradigm in head-fixed rats, which presents pulsatile vibrissa stimuli in seamless sequence for discrimination. This procedure ensures that processes of decision making can directly tap into sensory signals (no memory functions involved). We find that discrimination performance based on instantaneous kinematic cues far exceeds the ones provided by frequency and intensity. Neuronal modeling based on barrel cortex single units shows that small populations of sensitive neurons provide a transient signal that optimally fits the characteristic of the subject's perception. The present study is the first to show that perceptual read-out is superior in situations allowing the subject to base perception on detailed trajectory cues, that is, instantaneous kinematic variables. A possible impact of this finding on tactile systems of other species is suggested by evidence for instantaneous coding also in primates.

  5. A method to account for variation of average compressor inlet pressure during instantaneous distortion analyses

    NASA Technical Reports Server (NTRS)

    Burstadt, P. L.; Wenzel, L. M.

    1976-01-01

    A method is presented to calculate the available surge margin as a function of time and incorporate it into an instantaneous distortion analysis. Results show that inlet pressure variations which cause only a small change at the compressor exit can cause a significant variation in the available surge margin.

  6. Daily evapotranspiration estimates from extrapolating instantaneous airborne remote sensing ET values

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, six extrapolation methods have been compared for their ability to estimate daily crop evapotranspiration (ETd) from instantaneous latent heat flux estimates derived from digital airborne multispectral remote sensing imagery. Data used in this study were collected during an experiment...

  7. Estimation of the instantaneous rotation speed using complex shifted Morlet wavelets

    NASA Astrophysics Data System (ADS)

    Gryllias, Konstantinos C.; Antoniadis, Ioannis A.

    2013-07-01

    The ability of the complex continuous wavelet transform (CCWT) to provide also an estimation of the instantaneous frequency of a signal, parallel to the estimation of the instantaneous amplitude of the signal, is proposed as an approach for the estimation of the instantaneous rotation speed of machinery. Complex shifted Morlet wavelets (CSMW) present a number of advantages. The concept of shifting the Morlet wavelet in the frequency domain allows the simultaneous optimal selection of both the wavelet center frequency and the wavelet bandwidth. In this paper it is shown that the recovery of the signal frequency can be performed accurately, without the requirement that the wavelet center frequency coincides to the signal frequency. Contrarily, the accurate recovery of the signal amplitude requires additionally this last condition. The algorithm is tested on two synthetic signals and four non-stationary experimental vibration signals, in an experimental fault test rig and in a motorcycle engine. The proposed instantaneous frequency estimation approach presents very good results and in comparison to the Hilbert Transform achieves a significantly lower RMSE.

  8. Temporal pattern recognition based on instantaneous spike rate coding in a simple auditory system.

    PubMed

    Nabatiyan, A; Poulet, J F A; de Polavieja, G G; Hedwig, B

    2003-10-01

    Auditory pattern recognition by the CNS is a fundamental process in acoustic communication. Because crickets communicate with stereotyped patterns of constant frequency syllables, they are established models to investigate the neuronal mechanisms of auditory pattern recognition. Here we provide evidence that for the neural processing of amplitude-modulated sounds, the instantaneous spike rate rather than the time-averaged neural activity is the appropriate coding principle by comparing both coding parameters in a thoracic interneuron (Omega neuron ON1) of the cricket (Gryllus bimaculatus) auditory system. When stimulated with different temporal sound patterns, the analysis of the instantaneous spike rate demonstrates that the neuron acts as a low-pass filter for syllable patterns. The instantaneous spike rate is low at high syllable rates, but prominent peaks in the instantaneous spike rate are generated as the syllable rate resembles that of the species-specific pattern. The occurrence and repetition rate of these peaks in the neuronal discharge are sufficient to explain temporal filtering in the cricket auditory pathway as they closely match the tuning of phonotactic behavior to different sound patterns. Thus temporal filtering or "pattern recognition" occurs at an early stage in the auditory pathway.

  9. Validity and reliability of GPS for measuring instantaneous velocity during acceleration, deceleration, and constant motion.

    PubMed

    Varley, Matthew C; Fairweather, Ian H; Aughey, Robert J

    2012-01-01

    In this study, we assessed the validity and reliability of 5 and 10 Hz global positioning systems (GPS) for measuring instantaneous velocity during acceleration, deceleration, and constant velocity while straight-line running. Three participants performed 80 running trials while wearing two GPS units each (5 Hz, V2.0 and 10 Hz, V4.0; MinimaxX, Catapult Innovations, Scoresby, VIC, Australia). The criterion measure used to assess GPS validity was instantaneous velocity recorded using a tripod-mounted laser. Validity was established using the standard error of the estimate (± 90% confidence limits). Reliability was determined using typical error (± 90% confidence limits, expressed as coefficient of variation) and Pearson's correlation. The 10 Hz GPS devices were two to three times more accurate than the 5 Hz devices when compared with a criterion value for instantaneous velocity during tasks completed at a range of velocities (coefficient of variation 3.1-11.3%). Similarly, the 10 Hz GPS units were up to six-fold more reliable for measuring instantaneous velocity than the 5 Hz units (coefficient of variation 1.9-6.0%). Newer GPS may provide an acceptable tool for the measurement of constant velocity, acceleration, and deceleration during straight-line running and have sufficient sensitivity for detecting changes in performance in team sport. However, researchers must account for the inherent match-to-match variation reported when using these devices.

  10. Inhomogeneous Point-Processes to Instantaneously Assess Affective Haptic Perception through Heartbeat Dynamics Information.

    PubMed

    Valenza, G; Greco, A; Citi, L; Bianchi, M; Barbieri, R; Scilingo, E P

    2016-01-01

    This study proposes the application of a comprehensive signal processing framework, based on inhomogeneous point-process models of heartbeat dynamics, to instantaneously assess affective haptic perception using electrocardiogram-derived information exclusively. The framework relies on inverse-Gaussian point-processes with Laguerre expansion of the nonlinear Wiener-Volterra kernels, accounting for the long-term information given by the past heartbeat events. Up to cubic-order nonlinearities allow for an instantaneous estimation of the dynamic spectrum and bispectrum of the considered cardiovascular dynamics, as well as for instantaneous measures of complexity, through Lyapunov exponents and entropy. Short-term caress-like stimuli were administered for 4.3-25 seconds on the forearms of 32 healthy volunteers (16 females) through a wearable haptic device, by selectively superimposing two levels of force, 2 N and 6 N, and two levels of velocity, 9.4 mm/s and 65 mm/s. Results demonstrated that our instantaneous linear and nonlinear features were able to finely characterize the affective haptic perception, with a recognition accuracy of 69.79% along the force dimension, and 81.25% along the velocity dimension. PMID:27357966

  11. Inhomogeneous Point-Processes to Instantaneously Assess Affective Haptic Perception through Heartbeat Dynamics Information

    PubMed Central

    Valenza, G.; Greco, A.; Citi, L.; Bianchi, M.; Barbieri, R.; Scilingo, E. P.

    2016-01-01

    This study proposes the application of a comprehensive signal processing framework, based on inhomogeneous point-process models of heartbeat dynamics, to instantaneously assess affective haptic perception using electrocardiogram-derived information exclusively. The framework relies on inverse-Gaussian point-processes with Laguerre expansion of the nonlinear Wiener-Volterra kernels, accounting for the long-term information given by the past heartbeat events. Up to cubic-order nonlinearities allow for an instantaneous estimation of the dynamic spectrum and bispectrum of the considered cardiovascular dynamics, as well as for instantaneous measures of complexity, through Lyapunov exponents and entropy. Short-term caress-like stimuli were administered for 4.3–25 seconds on the forearms of 32 healthy volunteers (16 females) through a wearable haptic device, by selectively superimposing two levels of force, 2 N and 6 N, and two levels of velocity, 9.4 mm/s and 65 mm/s. Results demonstrated that our instantaneous linear and nonlinear features were able to finely characterize the affective haptic perception, with a recognition accuracy of 69.79% along the force dimension, and 81.25% along the velocity dimension. PMID:27357966

  12. 16 CFR Appendix D4 to Part 305 - Water Heaters-Instantaneous-Gas

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Water Heaters-Instantaneous-Gas D4 Appendix... CONGRESS RULE CONCERNING DISCLOSURES REGARDING ENERGY CONSUMPTION AND WATER USE OF CERTAIN HOME APPLIANCES AND OTHER PRODUCTS REQUIRED UNDER THE ENERGY POLICY AND CONSERVATION ACT (âAPPLIANCE LABELING...

  13. The 'reactive

    NASA Astrophysics Data System (ADS)

    Battista Piccardo, Giovanni; Guarnieri, Luisa

    2010-05-01

    The Ligurian ophiolitic peridotites [South Lanzo, Erro-Tobbio, Internal Ligurides and Corsica] are characterized by the abundance of spinel(Sp) peridotites showing depleted compositions and ranging from Cpx-poor Sp lherzolites to Sp harzburgites. They were recognized in the last decades as refractory residua by MORB-forming partial melting of the asthenosphere, and were similar to abyssal peridotites. Recent structural and compositional studies promoted a better understanding of their structural and compositional features and their genetic processes. In the field these depleted peridotites replace with primary contacts pyroxenite-bearing fertile Sp lherzolites that have been recognized as sub-continental lithospheric mantle. Field relationships evidence that decametric-hectometric bodies of pristine pyroxenite-veined lithospheric Sp lherzolites are preserved as structural remnants within the km-scale masses of depleted peridotites. The depleted peridotites show coarse-grained recrystallized textures and reaction micro-structures indicating pyroxene dissolution and olivine precipitation that have been considered as records of melt/peridotite interaction during reactive diffuse porous flow of undersaturated melts. They show, moreover, contrasting bulk and mineral chemistries that cannot be produced by simple partial melting and melt extraction. In particular, their bulk compositions are depleted in SiO2 and enriched in FeO with respect to refractory residua after any kind of partial melting, as calculated by Niu (1997), indicating that they cannot be formed by simple partial melting and melt extraction processes. Moreover, TiO2 content in Sp is usually significantly higher (up to 0.8-1.0 wt%) than typical TiO2 contents of spinels (usually < 0.1-0.2 wt %) in fertile mantle peridotites and melting refractory residua, indicating that spinel attained element equilibration with a Ti-bearing basaltic melt. The depleted peridotites usually show strongly variable Cpx modal

  14. Multifunctional reactive nanocomposite materials

    NASA Astrophysics Data System (ADS)

    Stamatis, Demitrios

    Many multifunctional nanocomposite materials have been developed for use in propellants, explosives, pyrotechnics, and reactive structures. These materials exhibit high reaction rates due to their developed reaction interfacial area. Two applications addressed in this work include nanocomposite powders prepared by arrested reactive milling (ARM) for burn rate modifiers and reactive structures. In burn rate modifiers, addition of reactive nanocomposite powders to aluminized propellants increases the burn rate of aluminum and thus the overall reaction rate of an energetic formulation. Replacing only a small fraction of aluminum by 8Al·MoO3 and 2B·Ti nanocomposite powders enhances the reaction rate with little change to the thermodynamic performance of the formulation; both the rate of pressure rise and maximum pressure measured in the constant volume explosion test increase. For reactive structures, nanocomposite powders with bulk compositions of 8Al·MoO3, 12Al·MoO3, and 8Al·3CuO were prepared by ARM and consolidated using a uniaxial die. Consolidated samples had densities greater than 90% of theoretical maximum density while maintaining their high reactivity. Pellets prepared using 8Al·MoO3 powders were ignited by a CO2 laser. Ignition delays increased at lower laser powers and greater pellet densities. A simplified numerical model describing heating and thermal initiation of the reactive pellets predicted adequately the observed effects of both laser power and pellet density on the measured ignition delays. To investigate the reaction mechanisms in nanocomposite thermites, two types of nanocomposite reactive materials with the same bulk compositions 8Al·MoO3 were prepared by different methods. One of the materials was manufactured by ARM and the other, so called metastable interstitial composite (MIC), by mixing of nano-scaled individual powders. Clear differences in the low-temperature redox reactions, welldetectable by differential scanning calorimetry

  15. Continuous measurements of instantaneous heart rate and its fluctuations before and after hatching in chickens.

    PubMed

    Moriya, K; Pearson, J T; Burggren, W W; Ar, A; Tazawa, H

    2000-03-01

    There has been considerable interest in heart rate (fh) fluctuations in relation to cardiovascular control systems and foetal conditions during pregnancy in mammals. Prominent fluctuations in fh also occur in avian embryos, which are an important experimental model for studying developmental physiology. The present study determined the instantaneous fh of seven chick embryos continuously from the last stage of prenatal development (day 18), throughout the pipping (perinatal) period (days 19-21) until hatching and, subsequently, of newly hatched chicks (up to day 2). The distinctive patterns of instantaneous fh fluctuations took the form of specific changes within a broad mean fh baseline. Cyclic oscillations (ultradian rhythm) occurred until an early stage of the perinatal period, when the fh baseline started rising. Subsequently, the baseline dropped and respiratory arrhythmia began to appear concomitant with external pipping. During the final stage of external pipping, when the fh baseline rose again prior to hatching, three unique patterns of instantaneous fh fluctuations were evident: relatively long-lasting cyclic small accelerations, irregular intermittent large accelerations and short-term repeated large accelerations. Furthermore, repeated alternate occurrences of the latter two types of acceleration formed an additional oscillating pattern with a period of 10-15 min. During the early period after hatching, when the fh baseline reached its maximum, instantaneous fh changed relatively slowly accompanied by transient rapid decelerations, probably due to augmented vagal tone. Subsequently, the mean fh baseline dropped to its minimum, and a circadian rhythm and three types of previously reported fh fluctuations (types I-III) appeared. Developmental patterns of mean fh and the appearance of distinctive patterns of instantaneous fluctuations in fh and circadian rhythms were not influenced by an ultimate failure of hatching after a normal development. The

  16. Instantaneous space-weighted ionospheric regional model for instantaneous mapping of the critical frequency of the F2 layer in the European region

    NASA Astrophysics Data System (ADS)

    Pietrella, Marco; Perrone, Loredana

    2005-02-01

    An instantaneous space-weighted ionospheric regional model (ISWIRM) for the regional now-casting of the critical frequency of the F2 layer (foF2) has been developed. The geographical area of applicability of the model is ranged between 35°N-70°N and 5°W-40°E. Inside this region the hourly values of foF2 are obtained, correcting the monthly medians values of foF2 predicted by the space-weighted ionospheric local model (SWILM) on the basis of hourly observations of foF2 coming from four reference stations (Rome, Chilton, Lycksele, and Loparskaya (or Sodankyla)). The performance of the model, evaluated at four testing stations (Tortosa, Juliusruh, Uppsala, and Kiruna) during some periods characterized by strong solar and geomagnetic activity, can be considered satisfactory, given that the hourly values of the residuals are almost always below 1 MHz. A comparison between ISWIRM's performance using manually validated and autoscaled data of foF2 and SWILM's performance was made for two disturbed periods. One example of instantaneous ionospheric mapping of foF2 relative to the selected disturbed periods is also shown.

  17. A robust method for analyzing the instantaneous attributes of seismic data: The instantaneous frequency estimation based on ensemble empirical mode decomposition

    NASA Astrophysics Data System (ADS)

    Li, Xiangfang; Chen, Wenchao; Zhou, Yanhui

    2014-12-01

    The Hilbert-Huang transform (HHT) includes two procedures. First, empirical mode decomposition (EMD) is used to decompose signals into several intrinsic mode functions (IMFs) before the Hilbert transform (HT) of these IMFs are calculated. Compared to the conventional Hilbert transform (HT), HHT is more sensitive to thickness variations of seismic beds. However, random noise in seismic signal may cause the mixture of the modes from HHT. The recent ensemble empirical mode decomposition (EEMD) presents the advantages in decreasing mode mixture and has the promising potential in seismic signal analysis. Currently, EEMD is mainly used in seismic spectral decomposition and noise attenuation. We extend the application of EEMD based instantaneous frequency to the analysis of bed thickness. The tests on complex Marmousi2 model and a 2D field data show that EEMD is more effective in weakening mode mixtures contained in the IMFs, compared with that calculated by EMD. Furthermore, the EEMD based instantaneous frequency is more sensitive to the seismic thickness variation than that based on EMD and more consistent with the stratigraphic structure, which means that E-IFPs are more advantageous in characterizing reservoirs.

  18. Reactivity change in a fast-spectrum space power reactor due to a 328-meter-per-second (1075-ft/sec) impact

    NASA Technical Reports Server (NTRS)

    Peoples, J. A., Jr.; Puthoff, R. L.

    1973-01-01

    Application of nuclear reactors in space will present operational problems. One such problem is the possibility of an earth impact at velocities in excess of 305 m/sec (1000 ft/sec). This report shows the results of an impact against concrete at 328 m/sec (1075 ft/sec) and examines the deformed core to estimate the range of activity inserted as a result of the impact. The results of this examination are that the deformation of the reactor core within the containment vessel left only an estimated 2.7 percent void in the core and that the reactivity inserted due to this impact deformation could be from 4.0 to 10.25 dollars.

  19. Instantaneous monitoring of sleep fragmentation by point process heart rate variability and respiratory dynamics.

    PubMed

    Citi, Luca; Bianchi, Matt T; Klerman, Elizabeth B; Barbieri, Riccardo

    2011-01-01

    We present a novel, automatic point-process approach that is able to provide continuous, instantaneous estimates of heart rate variability (HRV) and respiratory sinus arrhythmia (RSA) in long duration data recordings such as those during an entire night of sleep. We analyze subjects with and without sleep apnea who underwent diagnostic polysomnography. The proposed algorithm is able to quantify multi-scale high time resolution autonomic signatures of sleep fragmentation, such as arousals and stage transitions, throughout an entire night. Results demonstrate the ability of our methods to track fast dynamic transitions from sleep to wake and between REM sleep and other sleep stages, providing resolution details not available in sleep scoring summaries. An automatic threshold-based procedure is further able to detect brief arousals, with the instantaneous indices characterizing specific arousal dynamic signatures.

  20. Thermodynamics of Iodide Adsorption at the Instantaneous Air-Water Interface.

    SciTech Connect

    Stern, Abraham C.; Baer, Marcel D.; Mundy, Christopher J.; Tobias, Douglas J.

    2013-03-21

    We perform simulations using both polarizable and non-polarizable force fields to study the adsorption of iodide to the air-water interface. A novel aspect of our analysis is that the progress of the adsorption is measured as the distance from the instantaneous interface, which is defined by a coarse-graining scheme proposed recently by Willard and Chandler.\\cite{chandler1} Referring structural and thermodynamic quantities to the instantaneous interface unmasks molecular-scale details that are obscured by thermal fluctuations when the same quantities are referred to an average measure of the position of the interface, such as the Gibbs dividing surface. Our results suggest that an ion adsorbed at the interface resides primarily in the topmost layer water.

  1. Instantaneous pair theory for high-frequency vibrational energy relaxation in fluids

    NASA Astrophysics Data System (ADS)

    Larsen, Ross E.; Stratt, Richard M.

    1999-01-01

    Notwithstanding the long and distinguished history of studies of vibrational energy relaxation, exactly how it is that high frequency vibrations manage to relax in a liquid remains somewhat of a mystery. Both experimental and theoretical approaches seem to say that there is a natural frequency range associated with intermolecular motion in liquids, typically spanning no more than a few hundred cm-1. Landau-Teller-type theories explain rather easily how a solvent can absorb any vibrational energy within this "band," but how is it that molecules can rid themselves of superfluous vibrational energies significantly in excess of these values? In this paper we develop a theory for such processes based on the idea that the crucial liquid motions are those that most rapidly modulate the force on the vibrating coordinate — and that by far the most important of these motions are those involving what we have called the mutual nearest neighbors of the vibrating solute. Specifically, we suggest that whenever there is a single solvent molecule sufficiently close to the solute that the solvent and solute are each other's nearest neighbors, then the instantaneous scattering dynamics of the solute-solvent pair alone suffices to explain the high-frequency relaxation. This highly reduced version of the dynamics has implications for some of the previous theoretical formulations of this problem. Previous instantaneous-normal-mode theories allowed us to understand the origin of a band of liquid frequencies, and even had some success in predicting relaxation within this band, but lacking a sensible picture of the effects of liquid anharmonicity on dynamics, were completely unable to treat higher frequency relaxation. When instantaneous-normal-mode dynamics is used to evaluate the instantaneous pair theory, though, we end up with a multiphonon picture of the relaxation which is in excellent agreement with the exact high-frequency dynamics — suggesting that the critical anharmonicity

  2. Comparison of Signals from Gravitational Wave Detectors with Instantaneous Time-Frequency Maps

    NASA Technical Reports Server (NTRS)

    Stroeer, A.; Blackburn, L.; Camp, J.

    2011-01-01

    Gravitational wave astronomy relies on the use of multiple detectors, so that coincident detections may distinguish real signals from instrumental artifacts, and also so that relative timing of signals can provide the sky position of sources. We show that the comparison of instantaneous time-frequency and time-amplitude maps provided by the Hilbert-Huang Transform (HHT) can be used effectively for relative signal timing of common signals, to discriminate between the case of identical coincident signals and random noise coincidences and to provide a classification of signals based on their time-frequency trajectories. The comparison is done with a X(sup 2) goodness-offit method which includes contributions from both the instantaneous amplitude and frequency components of the HHT to match two signals in the time domain. This approach naturally allows the analysis of waveforms with strong frequency modulation.

  3. Comparison of signals from gravitational wave detectors with instantaneous time-frequency maps

    NASA Astrophysics Data System (ADS)

    Stroeer, A.; Blackburn, L.; Camp, J.

    2011-08-01

    Gravitational wave astronomy relies on the use of multiple detectors, so that coincident detections may distinguish real signals from instrumental artifacts, and also so that relative timing of signals can provide the sky position of sources. We show that the comparison of instantaneous time-frequency and time-amplitude maps provided by the Hilbert-Huang Transform (HHT) can be used effectively for relative signal timing of common signals, to discriminate between the case of identical coincident signals and random noise coincidences and to provide a classification of signals based on their time-frequency trajectories. The comparison is done with a χ2 goodness-of-fit method which includes contributions from both the instantaneous amplitude and frequency components of the HHT to match two signals in the time domain. This approach naturally allows the analysis of waveforms with strong frequency modulation.

  4. Dynamic hydrologic modeling using the zero-parameter Budyko model with instantaneous dryness index

    NASA Astrophysics Data System (ADS)

    Biswal, Basudev

    2016-09-01

    Long-term partitioning of hydrologic quantities is achieved by using the zero-parameter Budyko model which defines a dryness index. However, this approach is not suitable for dynamic partitioning particularly at diminishing timescales, and therefore, a universally applicable zero-parameter model remains elusive. Here an instantaneous dryness index is proposed which enables dynamic hydrologic modeling using the Budyko model. By introducing a "decay function" that characterizes the effects of antecedent rainfall and solar energy on the dryness state of a basin at a time, I propose the concept of instantaneous dryness index and use the Budyko function to perform continuous hydrologic partitioning. Using the same decay function, I then obtain discharge time series from the effective rainfall time series. The model is evaluated by considering data form 63 U.S. Geological Survey basins. Results indicate the possibility of using the proposed framework as an alternative platform for prediction in ungagued basins.

  5. Non-instantaneous growth characteristics of martensitic transformation in high Cr ferritic creep-resistant steel

    NASA Astrophysics Data System (ADS)

    Liu, Chenxi; Shao, Yi; Chen, Jianguo; Liu, Yongchang

    2016-08-01

    Microstructural observation and high-resolution dilatometry were employed to investigate kinetics of martensitic transformation in high Cr ferritic creep-resistant steel upon different quenching/cooling rates. By incorporating the classical athermal nucleation and impingement correction, a non-instantaneous growth model for martensitic transformation has been developed. The developed model describes austenite/martensite interface mobility during martensite growth. The growth rate of martensite is found to be varied from 1 × 10-6 to 3 × 10-6 m/s. The low interface mobility suggests that it is not appropriate to presume the instantaneous growth behavior of martensite. Moreover, based on the proposed model, nucleation rate of martensite under different cooling rates is found to be nearly the same, while the growth rate of martensite is promoted by increasing the cooling rate.

  6. Third post-Newtonian gravitational waveforms for compact binary systems in general orbits: Instantaneous terms

    NASA Astrophysics Data System (ADS)

    Mishra, Chandra Kant; Arun, K. G.; Iyer, Bala R.

    2015-04-01

    We compute the instantaneous contributions to the spherical harmonic modes of gravitational waveforms from compact binary systems in general orbits up to the third post-Newtonian (PN) order. We further extend these results for compact binaries in quasielliptical orbits using the 3PN quasi-Keplerian representation of the conserved dynamics of compact binaries in eccentric orbits. Using the multipolar post-Minkowskian formalism, starting from the different mass and current-type multipole moments, we compute the spin-weighted spherical harmonic decomposition of the instantaneous part of the gravitational waveform. These are terms which are functions of the retarded time and do not depend on the history of the binary evolution. Together with the hereditary part, which depends on the binary's dynamical history, these waveforms form the basis for construction of accurate templates for the detection of gravitational wave signals from binaries moving in quasielliptical orbits.

  7. Comparative study of reference currents and DC bus voltage control for Three-Phase Four-Wire Four-Leg SAPF to compensate harmonics and reactive power with 3D SVM.

    PubMed

    Chebabhi, A; Fellah, M K; Kessal, A; Benkhoris, M F

    2015-07-01

    In this paper the performances of three reference currents and DC bus voltage control techniques for Three-Phase Four-Wire Four-Leg SAPF are compared for balanced and unbalanced load conditions. The main goals are to minimize the harmonics, reduce the magnitude of neutral current, eliminate the zero-sequence current components caused by single-phase nonlinear loads and compensate the reactive power, and on the other hand improve performances such as robustness, stabilization, trajectory pursuit, and reduce time response. The three techniques are analyzed mathematically and simulation results are compared. The techniques considered for comparative study are the PI Control, Sliding Mode Control and the Backstepping Control. Synchronous reference frame theory (SRF) in the dqo-axes is used to generate the reference currents, of the inverter.

  8. Comparative study of reference currents and DC bus voltage control for Three-Phase Four-Wire Four-Leg SAPF to compensate harmonics and reactive power with 3D SVM.

    PubMed

    Chebabhi, A; Fellah, M K; Kessal, A; Benkhoris, M F

    2015-07-01

    In this paper the performances of three reference currents and DC bus voltage control techniques for Three-Phase Four-Wire Four-Leg SAPF are compared for balanced and unbalanced load conditions. The main goals are to minimize the harmonics, reduce the magnitude of neutral current, eliminate the zero-sequence current components caused by single-phase nonlinear loads and compensate the reactive power, and on the other hand improve performances such as robustness, stabilization, trajectory pursuit, and reduce time response. The three techniques are analyzed mathematically and simulation results are compared. The techniques considered for comparative study are the PI Control, Sliding Mode Control and the Backstepping Control. Synchronous reference frame theory (SRF) in the dqo-axes is used to generate the reference currents, of the inverter. PMID:25704056

  9. On the turbulent flow in piston engines: Coupling of statistical theory quantities and instantaneous turbulence

    NASA Astrophysics Data System (ADS)

    Zentgraf, Florian; Baum, Elias; Böhm, Benjamin; Dreizler, Andreas; Peterson, Brian

    2016-04-01

    Planar particle image velocimetry (PIV) and tomographic PIV (TPIV) measurements are utilized to analyze turbulent statistical theory quantities and the instantaneous turbulence within a single-cylinder optical engine. Measurements are performed during the intake and mid-compression stroke at 800 and 1500 RPM. TPIV facilitates the evaluation of spatially resolved Reynolds stress tensor (RST) distributions, anisotropic Reynolds stress invariants, and instantaneous turbulent vortical structures. The RST analysis describes distributions of individual velocity fluctuation components that arise from unsteady turbulent flow behavior as well as cycle-to-cycle variability (CCV). A conditional analysis, for which instantaneous PIV images are sampled by their tumble center location, reveals that CCV and turbulence have similar contributions to RST distributions at the mean tumble center, but turbulence is dominant in regions peripheral to the tumble center. Analysis of the anisotropic Reynolds stress invariants reveals the spatial distribution of axisymmetric expansion, axisymmetric contraction, and 3D isotropy within the cylinder. Findings indicate that the mid-compression flow exhibits a higher tendency toward 3D isotropy than the intake flow. A novel post-processing algorithm is utilized to classify the geometry of instantaneous turbulent vortical structures and evaluate their frequency of occurrence within the cylinder. Findings are coupled with statistical theory quantities to provide a comprehensive understanding of the distribution of turbulent velocity components, the distribution of anisotropic states of turbulence, and compare the turbulent vortical flow distribution that is theoretically expected to what is experimentally observed. The analyses reveal requisites of important turbulent flow quantities and discern their sensitivity to the local flow topography and engine operation.

  10. 16 CFR Appendix D4 to Part 305 - Water Heaters-Instantaneous-Gas

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Water Heaters-Instantaneous-Gas D4 Appendix...) Pt. 305, App. D4 Appendix D4 to Part 305—Water Heaters—Instantaneous—Gas Range Information Capacity.../year) Natural gas ($/year) LOW HIGH Propane ($/year) LOW HIGH Under 1.00 285 285 479 479 1.00 to...

  11. Estimating the Instantaneous Drag-Wind Relationship for a Horizontally Homogeneous Canopy

    NASA Astrophysics Data System (ADS)

    Pan, Ying; Chamecki, Marcelo; Nepf, Heidi M.

    2016-07-01

    The mean drag-wind relationship is usually investigated assuming that field data are representative of spatially-averaged metrics of statistically stationary flow within and above a horizontally homogeneous canopy. Even if these conditions are satisfied, large-eddy simulation (LES) data suggest two major issues in the analysis of observational data. Firstly, the streamwise mean pressure gradient is usually neglected in the analysis of data from terrestrial canopies, which compromises the estimates of mean canopy drag and provides misleading information for the dependence of local mean drag coefficients on local velocity scales. Secondly, no standard approach has been proposed to investigate the instantaneous drag-wind relationship, a critical component of canopy representation in LES. Here, a practical approach is proposed to fit the streamwise mean pressure gradient using observed profiles of the mean vertical momentum flux within the canopy. Inclusion of the fitted mean pressure gradient enables reliable estimates of the mean drag-wind relationship. LES data show that a local mean drag coefficient that characterizes the relationship between mean canopy drag and the velocity scale associated with total kinetic energy can be used to identify the dependence of the local instantaneous drag coefficient on instantaneous velocity. Iterative approaches are proposed to fit specific models of velocity-dependent instantaneous drag coefficients that represent the effects of viscous drag and the reconfiguration of flexible canopy elements. LES data are used to verify the assumptions and algorithms employed by these new approaches. The relationship between mean canopy drag and mean velocity, which is needed in models based on the Reynolds-averaged Navier-Stokes equations, is parametrized to account for both the dependence on velocity and the contribution from velocity variances. Finally, velocity-dependent drag coefficients lead to significant variations of the calculated

  12. Predicting physical stability in pressurized metered dose inhalers via dwell and instantaneous force colloidal probe microscopy.

    PubMed

    D'Sa, Dexter; Chan, Hak-Kim; Chrzanowski, Wojciech

    2014-09-01

    Colloidal probe microscopy (CPM) is a quantitative predictive tool, which can offer insight into particle behavior in suspension pressurized metered dose inhalers (pMDIs). Although CPM instantaneous force measurements, which involve immediate retraction of the probe upon sample contact, can provide information on inter-particle attractive forces, they lack the ability to appropriately imitate all critical particle pMDI interactions (e.g., particle re-dispersion after prolonged pMDI storage). In this paper, two novel dwell force techniques - indentation and deflection dwell - were employed to mimic long-term particle interactions present in pMDIs, using particles of various internal structures and a model liquid propellant (2H,3H perfluoropentane) as a model system. Dwell measurements involve particle contact for an extended period of time. In deflection dwell mode the probe is held at a specific position, while in indentation dwell mode the probe is forced into the sample with a constant force for the entirety of the contact time. To evaluate the applicability of CPM to predict actual pMDI physical stability, inter-particle force measurements were compared with qualitative and quantitative bulk pMDI measurement techniques (visual quality and light scattering). Measured instantaneous attractive (snap-in) and adhesive (max-pull) forces decreased as a function of increasing surface area, while adhesive forces measured by indentation dwell decreased as a function of dwell contact time for particles containing voids. Instantaneous force measurements provided information on the likelihood of floccule formation, which was predictive of partitioning rates, while indentation dwell force measurements were predictive of formulation re-dispersibility after prolonged storage. Dwell force measurements provide additional information on particle behavior within a pMDI not obtainable via instantaneous measurements. PMID:25058596

  13. Holographically emulating sequential versus instantaneous disappearance of vector mesons in a hot environment

    NASA Astrophysics Data System (ADS)

    Zöllner, R.; Kämpfer, B.

    2016-10-01

    Minor extensions of the soft-wall model are used to accommodate two variants of Regge trajectories of vector meson excitations. At nonzero temperatures, various options for either sequential or instantaneous disappearance of vector mesons as normalizable modes are found, thus emulating deconfinement at a certain temperature in the order of the (pseudo)critical temperature of QCD. The crucial role of the blackness function, which steers the thermodynamic properties of the considered system, is highlighted.

  14. Instantaneous estimation of motor cortical neural encoding for online brain-machine interfaces

    NASA Astrophysics Data System (ADS)

    Wang, Yiwen; Principe, Jose C.

    2010-10-01

    Recently, the authors published a sequential decoding algorithm for motor brain-machine interfaces (BMIs) that infers movement directly from spike trains and produces a new kinematic output every time an observation of neural activity is present at its input. Such a methodology also needs a special instantaneous neuronal encoding model to relate instantaneous kinematics to every neural spike activity. This requirement is unlike the tuning methods commonly used in computational neuroscience, which are based on time windows of neural and kinematic data. This paper develops a novel, online, encoding model that uses the instantaneous kinematic variables (position, velocity and acceleration in 2D or 3D space) to estimate the mean value of an inhomogeneous Poisson model. During BMI decoding the mapping from neural spikes to kinematics is one to one and easy to implement by simply reading the spike times directly. Due to the high temporal resolution of the encoding, the delay between motor cortex neurons and kinematics needs to be estimated in the encoding stage. Mutual information is employed to select the optimal time index defined as the lag for which the spike event is maximally informative with respect to the kinematics. We extensively compare the windowed tuning models with the proposed method. The big difference between them resides in the high firing rate portion of the tuning curve, which is rather important for BMI-decoding performance. This paper shows that implementing such an instantaneous tuning model in sequential Monte Carlo point process estimation based on spike timing provides statistically better kinematic reconstructions than the linear and exponential spike-tuning models.

  15. Estimation of Instantaneous Complex Dynamics through Lyapunov Exponents: A Study on Heartbeat Dynamics

    PubMed Central

    Valenza, Gaetano; Citi, Luca; Barbieri, Riccardo

    2014-01-01

    Measures of nonlinearity and complexity, and in particular the study of Lyapunov exponents, have been increasingly used to characterize dynamical properties of a wide range of biological nonlinear systems, including cardiovascular control. In this work, we present a novel methodology able to effectively estimate the Lyapunov spectrum of a series of stochastic events in an instantaneous fashion. The paradigm relies on a novel point-process high-order nonlinear model of the event series dynamics. The long-term information is taken into account by expanding the linear, quadratic, and cubic Wiener-Volterra kernels with the orthonormal Laguerre basis functions. Applications to synthetic data such as the Hénon map and Rössler attractor, as well as two experimental heartbeat interval datasets (i.e., healthy subjects undergoing postural changes and patients with severe cardiac heart failure), focus on estimation and tracking of the Instantaneous Dominant Lyapunov Exponent (IDLE). The novel cardiovascular assessment demonstrates that our method is able to effectively and instantaneously track the nonlinear autonomic control dynamics, allowing for complexity variability estimations. PMID:25170911

  16. Representation of Instantaneous and Short-Term Loudness in the Human Cortex

    PubMed Central

    Thwaites, Andrew; Glasberg, Brian R.; Nimmo-Smith, Ian; Marslen-Wilson, William D.; Moore, Brian C. J.

    2016-01-01

    Acoustic signals pass through numerous transforms in the auditory system before perceptual attributes such as loudness and pitch are derived. However, relatively little is known as to exactly when these transformations happen, and where, cortically or sub-cortically, they occur. In an effort to examine this, we investigated the latencies and locations of cortical entrainment to two transforms predicted by a model of loudness perception for time-varying sounds: the transforms were instantaneous loudness and short-term loudness, where the latter is hypothesized to be derived from the former and therefore should occur later in time. Entrainment of cortical activity was estimated from electro- and magneto-encephalographic (EMEG) activity, recorded while healthy subjects listened to continuous speech. There was entrainment to instantaneous loudness bilaterally at 45, 100, and 165 ms, in Heschl's gyrus, dorsal lateral sulcus, and Heschl's gyrus, respectively. Entrainment to short-term loudness was found in both the dorsal lateral sulcus and superior temporal sulcus at 275 ms. These results suggest that short-term loudness is derived from instantaneous loudness, and that this derivation occurs after processing in sub-cortical structures. PMID:27199645

  17. Representation of Instantaneous and Short-Term Loudness in the Human Cortex.

    PubMed

    Thwaites, Andrew; Glasberg, Brian R; Nimmo-Smith, Ian; Marslen-Wilson, William D; Moore, Brian C J

    2016-01-01

    Acoustic signals pass through numerous transforms in the auditory system before perceptual attributes such as loudness and pitch are derived. However, relatively little is known as to exactly when these transformations happen, and where, cortically or sub-cortically, they occur. In an effort to examine this, we investigated the latencies and locations of cortical entrainment to two transforms predicted by a model of loudness perception for time-varying sounds: the transforms were instantaneous loudness and short-term loudness, where the latter is hypothesized to be derived from the former and therefore should occur later in time. Entrainment of cortical activity was estimated from electro- and magneto-encephalographic (EMEG) activity, recorded while healthy subjects listened to continuous speech. There was entrainment to instantaneous loudness bilaterally at 45, 100, and 165 ms, in Heschl's gyrus, dorsal lateral sulcus, and Heschl's gyrus, respectively. Entrainment to short-term loudness was found in both the dorsal lateral sulcus and superior temporal sulcus at 275 ms. These results suggest that short-term loudness is derived from instantaneous loudness, and that this derivation occurs after processing in sub-cortical structures. PMID:27199645

  18. Inhomogeneous point-process entropy: An instantaneous measure of complexity in discrete systems

    NASA Astrophysics Data System (ADS)

    Valenza, Gaetano; Citi, Luca; Scilingo, Enzo Pasquale; Barbieri, Riccardo

    2014-05-01

    Measures of entropy have been widely used to characterize complexity, particularly in physiological dynamical systems modeled in discrete time. Current approaches associate these measures to finite single values within an observation window, thus not being able to characterize the system evolution at each moment in time. Here, we propose a new definition of approximate and sample entropy based on the inhomogeneous point-process theory. The discrete time series is modeled through probability density functions, which characterize and predict the time until the next event occurs as a function of the past history. Laguerre expansions of the Wiener-Volterra autoregressive terms account for the long-term nonlinear information. As the proposed measures of entropy are instantaneously defined through probability functions, the novel indices are able to provide instantaneous tracking of the system complexity. The new measures are tested on synthetic data, as well as on real data gathered from heartbeat dynamics of healthy subjects and patients with cardiac heart failure and gait recordings from short walks of young and elderly subjects. Results show that instantaneous complexity is able to effectively track the system dynamics and is not affected by statistical noise properties.

  19. The relationship between the instantaneous velocity field and the rate of moment release in the lithosphere

    USGS Publications Warehouse

    Pollitz, F.F.

    2003-01-01

    Instantaneous velocity gradients within the continental lithosphere are often related to the tectonic driving forces. This relationship is direct if the forces are secular, as for the case of loading of a locked section of a subduction interface by the downgoing plate. If the forces are static, as for the case of lateral variations in gravitational potential energy, then velocity gradients can be produced only if the lithosphere has, on average, zero strength. The static force model may be related to the long-term velocity field but not the instantaneous velocity field (typically measured geodetically over a period of several years) because over short time intervals the upper lithosphere behaves elastically. In order to describe both the short- and long-term behaviour of an (elastic) lithosphere-(viscoelastic) asthenosphere system in a self-consistent manner, I construct a deformation model termed the expected interseismic velocity (EIV) model. Assuming that the lithosphere is populated with faults that rupture continually, each with a definite mean recurrence time, and that the Earth is well approximated as a linear elastic-viscoelastic coupled system, I derive a simple relationship between the instantaneous velocity field and the average rate of moment release in the lithosphere. Examples with synthetic fault networks demonstrate that velocity gradients in actively deforming regions may to a large extent be the product of compounded viscoelastic relaxation from past earthquakes on hundreds of faults distributed over large (??? 106 km2) areas.

  20. Backstroke swimming: exploring gender differences in passive drag and instantaneous net drag force.

    PubMed

    Formosa, Danielle P; Sayers, Mark Gregory Leigh; Burkett, Brendan

    2013-12-01

    This study explored and quantified gender differences in passive drag and instantaneous net drag force profile for elite backstroke swimmers (FINA points 938 ± 71). Nine female and ten male backstroke swimmers completed eight maximum speed trials. During the passive drag condition participants were towed at the speed achieved within the maximum effort backstroke swimming trials, while holding a supine stationary streamline position. The remaining trials, swimmers performed their natural swimming stroke, while attached to an assisted towing device. Male participant's passive (P < .001) and mean net drag force (P < .001) were significantly higher compared with female participants. In addition, there were no significant differences by gender between either the minimum or maximum net drag forces produced during the left and right arm strokes. Instantaneous net drag force profiles demonstrated differences within and between individuals and genders. The swimmers who recorded the fastest speed also recorded the smallest difference in net drag force fluctuations. The instantaneous net drag force profile within elite backstroke swimming provides further insight into stroke technique of this sport.

  1. Quasi-Linear Cochlear Responses to Noise Can Result from Instantaneous Nonlinearities

    NASA Astrophysics Data System (ADS)

    Liu, Yi-Wen; Neely, Stephen T.

    2011-11-01

    Responses to acoustic stimuli in the cochlea are known to be nonlinear. Many existing models of cochlear mechanics were built upon three basic assumptions: traveling-wave amplification is provided by active mechanisms in the outer hair cells (OHCs). Second, as the stimulus level increases, the gain decreases due to saturation nonlinearity in the OHCs. Finally, the saturation non-linearity is "instantaneous"; its input-output relation does not possess memory. These assumptions were recently challenged by reports that basilar-membrane (BM) responses to noise can be predicted well by level-dependent Wiener filters and are thus quasi-linear. It was argued that the quasi-linear responses could not result from instantaneous nonlinearity. In this paper, we present a model of cochlear mechanics which has instantaneous OHC saturation nonlinearity but produces quasi-linear responses to noise. Correlation coefficients were consistently greater than 0.9 between simulated noise responses and the responses predicted by equivalent Wiener filters. Further, Gaussianity in the acoustic stimuli was preserved on the BM. We conclude that the results support the common understandings and assumptions of cochlear mechanics.

  2. Instantaneous ballistic velocity of suspended Brownian nanocrystals measured by upconversion nanothermometry

    NASA Astrophysics Data System (ADS)

    Brites, Carlos D. S.; Xie, Xiaoji; Debasu, Mengistie L.; Qin, Xian; Chen, Runfeng; Huang, Wei; Rocha, João; Liu, Xiaogang; Carlos, Luís D.

    2016-10-01

    Brownian motion is one of the most fascinating phenomena in nature. Its conceptual implications have a profound impact in almost every field of science and even economics, from dissipative processes in thermodynamic systems, gene therapy in biomedical research, artificial motors and galaxy formation to the behaviour of stock prices. However, despite extensive experimental investigations, the basic microscopic knowledge of prototypical systems such as colloidal particles in a fluid is still far from being complete. This is particularly the case for the measurement of the particles' instantaneous velocities, elusive due to the rapid random movements on extremely short timescales. Here, we report the measurement of the instantaneous ballistic velocity of Brownian nanocrystals suspended in both aqueous and organic solvents. To achieve this, we develop a technique based on upconversion nanothermometry. We find that the population of excited electronic states in NaYF4:Yb/Er nanocrystals at thermal equilibrium can be used for temperature mapping of the nanofluid with great thermal sensitivity (1.15% K‑1 at 296 K) and a high spatial resolution (<1 μm). A distinct correlation between the heat flux in the nanofluid and the temporal evolution of Er3+ emission allows us to measure the instantaneous velocity of nanocrystals with different sizes and shapes.

  3. Backstroke swimming: exploring gender differences in passive drag and instantaneous net drag force.

    PubMed

    Formosa, Danielle P; Sayers, Mark Gregory Leigh; Burkett, Brendan

    2013-12-01

    This study explored and quantified gender differences in passive drag and instantaneous net drag force profile for elite backstroke swimmers (FINA points 938 ± 71). Nine female and ten male backstroke swimmers completed eight maximum speed trials. During the passive drag condition participants were towed at the speed achieved within the maximum effort backstroke swimming trials, while holding a supine stationary streamline position. The remaining trials, swimmers performed their natural swimming stroke, while attached to an assisted towing device. Male participant's passive (P < .001) and mean net drag force (P < .001) were significantly higher compared with female participants. In addition, there were no significant differences by gender between either the minimum or maximum net drag forces produced during the left and right arm strokes. Instantaneous net drag force profiles demonstrated differences within and between individuals and genders. The swimmers who recorded the fastest speed also recorded the smallest difference in net drag force fluctuations. The instantaneous net drag force profile within elite backstroke swimming provides further insight into stroke technique of this sport. PMID:23271003

  4. Instantaneous transfer entropy for the study of cardio-respiratory dynamics.

    PubMed

    Valenza, Gaetano; Faes, Luca; Citi, Luca; Orini, Michele; Barbieri, Riccardo

    2015-01-01

    Measures of transfer entropy have been proposed to quantify the directional coupling and strength between two complex physiological variables. Particular attention has been given to nonlinear interactions within cardiovascular and respiratory dynamics as influenced by the autonomic nervous system. However, standard transfer entropy estimates have shown major limitations in dealing with issues concerning stochastic system modeling, limited observations in time, and the assumption of stationarity of the considered physiological variables. Moreover, standard estimates are unable to track time-varying changes in nonlinear coupling with high resolution in time. Here, we propose a novel definition of transfer entropy linked to inhomogeneous point-process theory. Heartbeat and respiratory dynamics are characterized through discrete time series, and modeled through probability density functions (PDFs) which characterize and predict the time until the occurrence of the next physiological event as a function of the past history. As the derived measures of entropy are instantaneously defined through continuos PDFs, a novel index (the Instantaneous point-process Transfer Entropy, ipT ransfEn) is able to provide instantaneous tracking of the information transfer. The new measure is tested on experimental data gathered from 16 healthy subjects undergoing postural changes, showing fast tracking of the tilting events and low variability during the standing phase.

  5. Dynamics of the instantaneous firing rate in response to changes in input statistics.

    PubMed

    Fourcaud-Trocmé, Nicolas; Brunel, Nicolas

    2005-06-01

    We review and extend recent results on the instantaneous firing rate dynamics of simplified models of spiking neurons in response to noisy current inputs. It has been shown recently that the response of the instantaneous firing rate to small amplitude oscillations in the mean inputs depends in the large frequency limit f on the spike initiation dynamics. A particular simplified model, the exponential integrate-and-fire (EIF) model, has a response that decays as 1/f in the large frequency limit and describes very well the response of conductance-based models with a Hodgkin-Huxley type fast sodium current. Here, we show that the response of the EIF instantaneous firing rate also decays as 1/f in the case of an oscillation in the variance of the inputs for both white and colored noise. We then compute the initial transient response of the firing rate of the EIF model to a step change in its mean inputs and/or in the variance of its inputs. We show that in both cases the response speed is proportional to the neuron stationary firing rate and inversely proportional to a 'spike slope factor' Delta(T) that controls the sharpness of spike initiation: as 1/Delta(T) for a step change in mean inputs, and as 1/Delta(T) (2) for a step change in the variance in the inputs.

  6. Impulsive model for reactive collisions

    NASA Technical Reports Server (NTRS)

    Marron, M. T.; Bernstein, R. B.

    1972-01-01

    A simple classical mechanical model of the reactive scattering of a structureless atom A and a quasi-diatomic BC is developed which takes full advantage of energy, linear and angular momentum conservation relations but introduces a minimum of further assumptions. These are as follows: (1) the vibrational degree of freedom of the reactant (BC) and product (AB) molecules is suppressed, so the change in vibrational energy is simply a parameter; (2) straight-line trajectories are assumed outside of a reaction shell; (3) within this zone, momentum transfer occurs impulsively (essentially instantaneously) following mass transfer; (4) the impulse, which may be either positive or negative, is directed along the BC axis, which may, however, assume all orientations with respect to the incident relative velocity. The model yields differential and total cross sections and product rotational energy distributions for a given collision exoergicity Q, or for any known distribution over Q. Numerical results are presented for several prototype reactions whose dynamics have been well-studied.

  7. The antioxidative power AP—A new quantitative time dependent (2D) parameter for the determination of the antioxidant capacity and reactivity of different plants

    NASA Astrophysics Data System (ADS)

    Jung, Katinka; Richter, J.; Kabrodt, K.; Lücke, I. M.; Schellenberg, I.; Herrling, Th.

    2006-03-01

    In the last decade, naturally occurring antioxidants continue to play an important role in the food-supplement industry. The content of antioxidants in a plant depends on the species, temperature, humidity, period of growth, harvest month, part of the plant used and many other variables. Herein, we present a new method able to determine the all over antioxidative power (AP) of plant extracts or lyophilised plant parts based on the reducing activity against a stable test radical. The method is performed by ESR spectroscopy and is based on the well-known 1,1-diphenyl-2-picryl-hydrazil (DPPH) method with the major difference that both the antioxidative capacity and the antioxidative activity are used to characterise an antioxidant. The resulting antioxidative power is expressed in antioxidative units (AU), where 1 AU corresponds to the activity of a 1 ppm solution of Vitamin C as a benchmark. This method allows a rapid, unexpensive and general applicable technique for the measurement of the antioxidative power of very different kinds of substances. The inclusion of the kinetic behaviour of the reducing process of the antioxidant for the determination of the AP allows the identification of the main antioxidant present in a sample. Herein, we present the application example of seeds, sprouts and adult parts of dandelion, amaranth, quinoa, fenugreek, broccoli, red clover and mugwort, where the AP method permits to characterise the plants with the highest antioxidant capacity and reaction velocity. The method permits to select active plant extracts for the food and nutrition industry.

  8. Mark 22 Reactivity

    SciTech Connect

    Buckner, M.R.

    2001-07-02

    Calculations for reactivity held in control rods have underpredicted the observed Mark 22 reactivity. Reactivity predictions by charge designers have accounted for this by including large biases which change with exposure and reactor region. The purpose of this study was to thoroughly investigate the methods and data used in the reactivity calculations. The goal was to identify errors and improvements and make necessary corrections.

  9. Robust triboelectric nanogenerator based on rolling electrification and electrostatic induction at an instantaneous energy conversion efficiency of ∼ 55%.

    PubMed

    Lin, Long; Xie, Yannan; Niu, Simiao; Wang, Sihong; Yang, Po-Kang; Wang, Zhong Lin

    2015-01-27

    In comparison to in-pane sliding friction, rolling friction not only is likely to consume less mechanical energy but also presents high robustness with minimized wearing of materials. In this work, we introduce a highly efficient approach for harvesting mechanical energy based on rolling electrification and electrostatic induction, aiming at improving the energy conversion efficiency and device durability. The rolling triboelectric nanogenerator is composed of multiple steel rods sandwiched by two fluorinated ethylene propylene (FEP) thin films. The rolling motion of the steel rods between the FEP thin films introduces triboelectric charges on both surfaces and leads to the change of potential difference between each pair of electrodes on back of the FEP layer, which drives the electrons to flow in the external load. As power generators, each pair of output terminals works independently and delivers an open-circuit voltage of 425 V, and a short-circuit current density of 5 mA/m(2). The two output terminals can also be integrated to achieve an overall power density of up to 1.6 W/m(2). The impacts of variable structural factors were investigated for optimization of the output performance, and other prototypes based on rolling balls were developed to accommodate different types of mechanical energy sources. Owing to the low frictional coefficient of the rolling motion, an instantaneous energy conversion efficiency of up to 55% was demonstrated and the high durability of the device was confirmed. This work presents a substantial advancement of the triboelectric nanogenerators toward large-scope energy harvesting and self-powered systems.

  10. Robust triboelectric nanogenerator based on rolling electrification and electrostatic induction at an instantaneous energy conversion efficiency of ∼ 55%.

    PubMed

    Lin, Long; Xie, Yannan; Niu, Simiao; Wang, Sihong; Yang, Po-Kang; Wang, Zhong Lin

    2015-01-27

    In comparison to in-pane sliding friction, rolling friction not only is likely to consume less mechanical energy but also presents high robustness with minimized wearing of materials. In this work, we introduce a highly efficient approach for harvesting mechanical energy based on rolling electrification and electrostatic induction, aiming at improving the energy conversion efficiency and device durability. The rolling triboelectric nanogenerator is composed of multiple steel rods sandwiched by two fluorinated ethylene propylene (FEP) thin films. The rolling motion of the steel rods between the FEP thin films introduces triboelectric charges on both surfaces and leads to the change of potential difference between each pair of electrodes on back of the FEP layer, which drives the electrons to flow in the external load. As power generators, each pair of output terminals works independently and delivers an open-circuit voltage of 425 V, and a short-circuit current density of 5 mA/m(2). The two output terminals can also be integrated to achieve an overall power density of up to 1.6 W/m(2). The impacts of variable structural factors were investigated for optimization of the output performance, and other prototypes based on rolling balls were developed to accommodate different types of mechanical energy sources. Owing to the low frictional coefficient of the rolling motion, an instantaneous energy conversion efficiency of up to 55% was demonstrated and the high durability of the device was confirmed. This work presents a substantial advancement of the triboelectric nanogenerators toward large-scope energy harvesting and self-powered systems. PMID:25555045

  11. Uncertainty assessment of 3D instantaneous velocity model from stack velocities

    NASA Astrophysics Data System (ADS)

    Emanuele Maesano, Francesco; D'Ambrogi, Chiara

    2015-04-01

    3D modelling is a powerful tool that is experiencing increasing applications in data analysis and dissemination. At the same time the need of quantitative uncertainty evaluation is strongly requested in many aspects of the geological sciences and by the stakeholders. In many cases the starting point for 3D model building is the interpretation of seismic profiles that provide indirect information about the geology of the subsurface in the domain of time. The most problematic step in the 3D modelling construction is the conversion of the horizons and faults interpreted in time domain to the depth domain. In this step the dominant variable that could lead to significantly different results is the velocity. The knowledge of the subsurface velocities is related mainly to punctual data (sonic logs) that are often sparsely distributed in the areas covered by the seismic interpretation. The extrapolation of velocity information to wide extended horizons is thus a critical step to obtain a 3D model in depth that can be used for predictive purpose. In the EU-funded GeoMol Project, the availability of a dense network of seismic lines (confidentially provided by ENI S.p.A.) in the Central Po Plain, is paired with the presence of 136 well logs, but few of them have sonic logs and in some portion of the area the wells are very widely spaced. The depth conversion of the 3D model in time domain has been performed testing different strategies for the use and the interpolation of velocity data. The final model has been obtained using a 4 layer cake 3D instantaneous velocity model that considers both the initial velocity (v0) in every reference horizon and the gradient of velocity variation with depth (k). Using this method it is possible to consider the geological constraint given by the geometries of the horizons and the geo-statistical approach to the interpolation of velocities and gradient. Here we present an experiment based on the use of set of pseudo-wells obtained from the

  12. High efficiency, quasi-instantaneous steam expansion device utilizing fossil or nuclear fuel as the heat source

    SciTech Connect

    Claudio Filippone, Ph.D.

    1999-06-01

    Thermal-hydraulic analysis of a specially designed steam expansion device (heat cavity) was performed to prove the feasibility of steam expansions at elevated rates for power generation with higher efficiency. The steam expansion process inside the heat cavity greatly depends on the gap within which the steam expands and accelerates. This system can be seen as a miniaturized boiler integrated inside the expander where steam (or the proper fluid) is generated almost instantaneously prior to its expansion in the work-producing unit. Relatively cold water is pulsed inside the heat cavity, where the heat transferred causes the water to flash to steam, thereby increasing its specific volume by a large factor. The gap inside the heat cavity forms a special nozzle-shaped system in which the fluid expands rapidly, accelerating toward the system outlet. The expansion phenomenon is the cause of ever-increasing fluid speed inside the cavity system, eliminating the need for moving parts (pumps, valves, etc.). In fact, the subsequent velocity induced by the sudden fluid expansion causes turbulent conditions, forcing accelerating Reynolds and Nusselt numbers which, in turn, increase the convective heat transfer coefficient. When the combustion of fossil fuels constitutes the heat source, the heat cavity concept can be applied directly inside the stator of conventional turbines, thereby greatly increasing the overall system efficiency.

  13. Numerical modeling of forceful pluton emplacement and associated deformation at different crustal levels - instantaneous, continuous or episodic intrusion?

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Nabelek, P. I.

    2015-12-01

    The Papoose Flat pluton in the White-Inyo Range, California, is one of the best examples of forceful magma emplacement at mid-crustal levels that is revealed by a highly strained aureole. A thermo-rheological 2-D model of the pluton and its aureole is proposed. We explored how the frequency of magma input, from instantaneous to continuous to the bottom of the laccolith, affects the ductile width of the aureole and the crystallinity of the pluton, which has implications for eruption of magma. We modeled these aspects at mid- and upper-crustal levels. The pluton was assumed to be 5 km thick in the middle and 13 km wide. Except for instantaneous growth, pluton was assumed to grow over 5 m.y. The aureole was assumed to have power-law rheology of quartz with dependence on H2O fugacity, which was calculated using the CORK equation (Holland & Powell, 1991) Our result shows that the bottom of the Papoose Flat pluton was emplaced at the brittle-ductile transition zone of the crust. The crustal rheology profile assisted the softening of rocks around the pluton. The simulated temperature and strength profiles confirm that ductile deformation was related to thermal weakening (Saint-Blanquat et al., 2001). Results of incremental growth calculations show that the pluton remains hot and only partially crystalline for millions of years when it grows by frequent input of small batches of liquid. At the mid-crustal level, the ductile region around the pluton is much wider and exists longer than at the shallow crustal level. Brittle rheology is dominant during the late stage growth at the shallow depth. When the pluton grows instantly or by only few episodes of large batches of input, the mobile part of the pluton is thin and the ductile aureole is narrower. High-frequency incremental growth by smaller magma batches produces a large volume of mobile magma that has the potential to induce internal magmatic layering that may be reflected in aligned acquired magnetic susceptibility (AMS

  14. Nonlinear structural joint model updating based on instantaneous characteristics of dynamic responses

    NASA Astrophysics Data System (ADS)

    Wang, Zuo-Cai; Xin, Yu; Ren, Wei-Xin

    2016-08-01

    This paper proposes a new nonlinear joint model updating method for shear type structures based on the instantaneous characteristics of the decomposed structural dynamic responses. To obtain an accurate representation of a nonlinear system's dynamics, the nonlinear joint model is described as the nonlinear spring element with bilinear stiffness. The instantaneous frequencies and amplitudes of the decomposed mono-component are first extracted by the analytical mode decomposition (AMD) method. Then, an objective function based on the residuals of the instantaneous frequencies and amplitudes between the experimental structure and the nonlinear model is created for the nonlinear joint model updating. The optimal values of the nonlinear joint model parameters are obtained by minimizing the objective function using the simulated annealing global optimization method. To validate the effectiveness of the proposed method, a single-story shear type structure subjected to earthquake and harmonic excitations is simulated as a numerical example. Then, a beam structure with multiple local nonlinear elements subjected to earthquake excitation is also simulated. The nonlinear beam structure is updated based on the global and local model using the proposed method. The results show that the proposed local nonlinear model updating method is more effective for structures with multiple local nonlinear elements. Finally, the proposed method is verified by the shake table test of a real high voltage switch structure. The accuracy of the proposed method is quantified both in numerical and experimental applications using the defined error indices. Both the numerical and experimental results have shown that the proposed method can effectively update the nonlinear joint model.

  15. An instantaneous colorimetric protein assay based on spontaneous formation of a protein corona on gold nanoparticles.

    PubMed

    Ho, Yan Teck; Poinard, Barbara; Yeo, Eugenia Li Ling; Kah, James Chen Yong

    2015-02-21

    Commercial protein assays used ubiquitously in laboratories typically require long incubation times due to the inherently slow protein-reagent reactions. In this study, we report a novel facile technique for the instantaneous measurement of total protein concentration by exploiting the rapid aggregation dynamics of gold nanoparticles (NPs). By adsorbing different amounts of proteins on their surface to form a protein corona, these NPs can be sterically stabilized to different degrees by aggregation, thus exhibiting a spectrum of color change which can be quantitatively characterized by UV-Vis absorption spectroscopy. We evaluated this technique on four model proteins with different structures: bovine serum albumin (BSA), normal mouse immunoglobulin G (IgG), fibrinogen (FBG) and apolipoprotein A-I (Apo-A1) using two approaches, sequential and simultaneous. We obtained an approach-dependent linear concentration range up to 80 μg mL(-1) and 400 μg mL(-1) for sequential and simultaneous approaches, respectively. This linear working range was wider than that of the commercial Bradford assay and comparable to the Micro BCA assay. The simultaneous approach was also able to produce a linear working range of 200 to 1000 μg mL(-1) (R(2) = 0.995) in human urine, while the sequential approach was non-functional in urine. Similar to Micro BCA, the NP-based protein assay was able to elicit a linear response (R(2) > 0.87) for all four proteins with different structures. However, unlike Micro BCA which requires up to 120 min of incubation, we were able to obtain the read-out almost instantaneously without the need for incubation. The NP-based technique using the simultaneous approach can thus be exploited as a novel assay for instantaneous protein quantification to increase the productivity of laboratory processes.

  16. Comparisons of Instantaneous TRMM Ground Validation and Satellite Rain Rate Estimates at Different Spatial Scales

    NASA Technical Reports Server (NTRS)

    Wolff, David B.; Fisher, Brad L.

    2007-01-01

    This study provides a comprehensive inter-comparison of instantaneous rain rates observed by the two rain sensors aboard the TRMM satellite with ground data from two regional sites established for long-term ground validation: Kwajalein Atoll and Melbourne, Florida. The satellite rain algorithms utilize remote observations of precipitation collected by the TRMM microwave imager (TMI) and the Precipitation Radar (PR) aboard the TRMM satellite. Three standard Level I1 rain products are generated from operational applications of the TMI, PR and Combined (COM) rain algorithms using rain information collected from the TMI and the PR along the orbital track of the TRMM satellite. In the first part of the study, 0.25 x 0.25 instantaneous rain rates obtained from the TRMM 3668 product were analyzed and compared to instantaneous GV rain rates gridded at a scale of 0.5deg x 0.5. In the second part of the study, TMI, PR, COM and GV rain rates were spatio-temporally matched and averaged at the scale of TMI footprint (- 150 sq km). This study covered a six-year period 1999-2004 and consisted of over 50,000 footprints for each GV site. In the first analysis our results showed that all of the respective rain rate estimates agree well, with some exceptions. The more salient differences were associated with heavy rain events in which one or more of the algorithms failed to properly retrieve these extreme events. Also, it appears that there is a preferred mode of precipitation for TMI rain rates at or near 2 mm/hr over the ocean. This mode was noted over ocean areas of Kwajalein and Melbourne and has been observed in TRMM tropical-global ocean areas as well.

  17. Instantaneous kinematic phase reflects neuromechanical response to lateral perturbations of running cockroaches.

    PubMed

    Revzen, Shai; Burden, Samuel A; Moore, Talia Y; Mongeau, Jean-Michel; Full, Robert J

    2013-04-01

    Instantaneous kinematic phase calculation allows the development of reduced-order oscillator models useful in generating hypotheses of neuromechanical control. When perturbed, changes in instantaneous kinematic phase and frequency of rhythmic movements can provide details of movement and evidence for neural feedback to a system-level neural oscillator with a time resolution not possible with traditional approaches. We elicited an escape response in cockroaches (Blaberus discoidalis) that ran onto a movable cart accelerated laterally with respect to the animals' motion causing a perturbation. The specific impulse imposed on animals (0.50 [Formula: see text] 0.04 m s[Formula: see text]; mean, SD) was nearly twice their forward speed (0.25 [Formula: see text] 0.06 m s[Formula: see text]. Instantaneous residual phase computed from kinematic phase remained constant for 110 ms after the onset of perturbation, but then decreased representing a decrease in stride frequency. Results from direct muscle action potential recordings supported kinematic phase results in showing that recovery begins with self-stabilizing mechanical feedback followed by neural feedback to an abstracted neural oscillator or central pattern generator. Trials fell into two classes of forward velocity changes, while exhibiting statistically indistinguishable frequency changes. Animals pulled away from the side with front and hind legs of the tripod in stance recovered heading within 300 ms, whereas animals that only had a middle leg of the tripod resisting the pull did not recover within this period. Animals with eight or more legs might be more robust to lateral perturbations than hexapods.

  18. Hyporheic Temperature Dynamics: Predicting Hyporheic Temperatures Based on Travel Time Assuming Instantaneous Water-Sediment Conduction

    NASA Astrophysics Data System (ADS)

    Kraseski, K. A.

    2015-12-01

    Recently developed conceptual frameworks and new observations have improved our understanding of hyporheic temperature dynamics and their effects on channel temperatures. However, hyporheic temperature models that are both simple and useful remain elusive. As water moves through hyporheic pathways, it exchanges heat with hyporheic sediment through conduction, and this process dampens the diurnal temperature wave of the water entering from the channel. This study examined the mechanisms underlying this behavior, and utilized those findings to create two simple models that predict temperatures of water reentering the channel after traveling through hyporheic pathways for different lengths of time. First, we developed a laboratory experiment to represent this process and determine conduction rates for various sediment size classes (sand, fine gravel, coarse gravel, and a proportional mix of the three) by observing the time series of temperature changes between sediment and water of different initial temperatures. Results indicated that conductions rates were near-instantaneous, with heat transfer being completed on the scale of seconds to a few minutes of the initial interaction. Heat conduction rates between the sediment and water were therefore much faster than hyporheic flux rates, rendering reasonable an assumption of instantaneous conduction. Then, we developed two simple models to predict time series of hyporheic water based on the initial diurnal temperature wave and hyporheic travel distance. The first model estimates a damping coefficient based on the total water-sediment heat exchange through each diurnal cycle. The second model solves the heat transfer equation assuming instantaneous conduction using a simple finite difference algorithm. Both models demonstrated nearly complete damping of the sine wave over the distance traveled in four days. If hyporheic exchange is substantial and travel times are long, then hyporheic damping may have large effects on

  19. Wing inertia and whole-body acceleration: an analysis of instantaneous aerodynamic force production in cockatiels (Nymphicus hollandicus) flying across a range of speeds.

    PubMed

    Hedrick, Tyson L; Usherwood, James R; Biewener, Andrew A

    2004-04-01

    We used a combination of high-speed 3-D kinematics and three-axis accelerometer recordings obtained from cockatiels flying in a low-turbulence wind tunnel to characterize the instantaneous accelerations and, by extension, the net aerodynamic forces produced throughout the wingbeat cycle across a broad range of flight speeds (1-13 m s(-1)). Our goals were to investigate the variation in instantaneous aerodynamic force production during the wingbeat cycle of birds flying across a range of steady speeds, testing two predictions regarding aerodynamic force generation in upstroke and the commonly held assumption that all of the kinetic energy imparted to the wings of a bird in flapping flight is recovered as useful aerodynamic work. We found that cockatiels produce only a limited amount of lift during upstroke (14% of downstroke lift) at slower flight speeds (1-3 m s(-1)). Upstroke lift at intermediate flight speeds (7-11 m s(-1)) was moderate, averaging 39% of downstroke lift. Instantaneous aerodynamic forces were greatest near mid-downstroke. At the end of each half-stroke, during wing turnaround, aerodynamic forces were minimal, but inertial forces created by wing motion were large. However, we found that the inertial power requirements of downstroke (minimum of 0.29+/-0.10 W at 7 m s(-1) and maximum of 0.56+/-0.13 W at 1 m s(-1)) were consistent with the assumption that nearly all wing kinetic energy in downstroke was applied to the production of aerodynamic forces and therefore should not be added separately to the overall power cost of flight. The inertial power requirements of upstroke (minimum of 0.16+/-0.04 W at 7 m s(-1) and maximum of 0.35+/-0.11 W at 1 m s(-1)) cannot be recovered in a similar manner, but their magnitude was such that the power requirements for the upstroke musculature (minimum of 54+/-13 W kg(-1) at 7 m s(-1) and maximum of 122+/-35 W at 1 m s(-1)) fall within the established range for cockatiel flight muscle (<185 W kg(-1)).

  20. Wing inertia and whole-body acceleration: an analysis of instantaneous aerodynamic force production in cockatiels (Nymphicus hollandicus) flying across a range of speeds.

    PubMed

    Hedrick, Tyson L; Usherwood, James R; Biewener, Andrew A

    2004-04-01

    We used a combination of high-speed 3-D kinematics and three-axis accelerometer recordings obtained from cockatiels flying in a low-turbulence wind tunnel to characterize the instantaneous accelerations and, by extension, the net aerodynamic forces produced throughout the wingbeat cycle across a broad range of flight speeds (1-13 m s(-1)). Our goals were to investigate the variation in instantaneous aerodynamic force production during the wingbeat cycle of birds flying across a range of steady speeds, testing two predictions regarding aerodynamic force generation in upstroke and the commonly held assumption that all of the kinetic energy imparted to the wings of a bird in flapping flight is recovered as useful aerodynamic work. We found that cockatiels produce only a limited amount of lift during upstroke (14% of downstroke lift) at slower flight speeds (1-3 m s(-1)). Upstroke lift at intermediate flight speeds (7-11 m s(-1)) was moderate, averaging 39% of downstroke lift. Instantaneous aerodynamic forces were greatest near mid-downstroke. At the end of each half-stroke, during wing turnaround, aerodynamic forces were minimal, but inertial forces created by wing motion were large. However, we found that the inertial power requirements of downstroke (minimum of 0.29+/-0.10 W at 7 m s(-1) and maximum of 0.56+/-0.13 W at 1 m s(-1)) were consistent with the assumption that nearly all wing kinetic energy in downstroke was applied to the production of aerodynamic forces and therefore should not be added separately to the overall power cost of flight. The inertial power requirements of upstroke (minimum of 0.16+/-0.04 W at 7 m s(-1) and maximum of 0.35+/-0.11 W at 1 m s(-1)) cannot be recovered in a similar manner, but their magnitude was such that the power requirements for the upstroke musculature (minimum of 54+/-13 W kg(-1) at 7 m s(-1) and maximum of 122+/-35 W at 1 m s(-1)) fall within the established range for cockatiel flight muscle (<185 W kg(-1)). PMID:15073202

  1. Method for generating a highly reactive plasma for exhaust gas after treatment and enhanced catalyst reactivity

    SciTech Connect

    Whealton, John H.; Hanson, Gregory R.; Storey, John M.; Raridon, Richard J.; Armfield, Jeffrey S.; Bigelow, Timothy S.; Graves, Ronald L.

    2000-07-01

    This patent application describes a method and apparatus of exhaust gas remediation that enhance the reactivity of the material catalysts found within catalytic converters of cars, trucks, and power stations.

  2. Surface treatment of diamond-like carbon films by reactive Ar/CF4 high-power pulsed magnetron sputtering plasmas

    NASA Astrophysics Data System (ADS)

    Kimura, Takashi; Nishimura, Ryotaro; Azuma, Kingo; Nakao, Setsuo; Sonoda, Tsutomu; Kusumori, Takeshi; Ozaki, Kimihiro

    2015-12-01

    Surface modification of diamond-like carbon films deposited by a high-power pulsed magnetron sputtering (HPPMS) of Ar was carried out by a HPPMS of Ar/CF4 mixture, changing a CF4 fraction from 2.5% to 20%. The hardness of the modified films markedly decreased from about 13 to about 3.5 GPa with increasing CF4 fraction, whereas the water contact angle of the modified films increased from 68° to 109° owing to the increase in the CFx content on the film surface. C 1s spectra in X-ray photoelectron spectroscopy indicated that a graphitic structure of modified films was formed at CF4 fractions less than 5%, above which the modified films possessed a polymer-like structure. Influence of treatment time on the properties of the modified films was also investigated in the range of treatment time from 5 to 30 min. The properties of the modified films did not depend on the treatment time in the range of treatment time longer than 10 min, whereas the water contact angle was not sensitive to the treatment time at any treatment time.

  3. Total-body irradiation and cataract incidence: A randomized comparison of two instantaneous dose rates

    SciTech Connect

    Ozsahin, M.; Belkacemi, Y.; Pene, F.; Dominique, C.; Schwartz, L.H.; Uzal, C.; Lefkopoulos, D.; Gindrey-Vie, B.; Vitu-Loas, L.; Touboul, E. )

    1994-01-15

    To assess the influence of instantaneous total-body irradiation dose rate in hematological malignancies, the authors randomized 157 patients according to different instantaneous dose rates. Patients have undergone a total-body irradiation before bone-marrow transplantation according to two different techniques: Either in one fraction (1000 cGy given to the midplane at the level of L4, and 800 cGy to the lungs) or in six fractions (1200 cGy over 3 consecutive days to the midplane at the level of L4, and 900 cGy to the lungs). Patients were randomized according to two instantaneous dose rates, called LOW and HIGH, in single-dose (6 vs. 15 cGy/min) and fractionated (3 vs. 6 cGy/min) TBI groups; there were 77 cases for the LOW and 80 for the HIGH groups, with 57 patients receiving single-dose (28 LOW, 29 HIGH) and 100 patients receiving fractionated total-body irradiation (49 LOW, 51 HIGH). As of July 1992, 16 of 157 patients developed cataracts after 17 to 46 months, with an estimated incidence of 23% at 5 years. Four of 77 patients in the LOW group, 12 of 80 patients in the HIGH group developed cataracts, with 5-year estimated incidences of 12% and 34%, respectively. Ten of 57 patients in the single-dose group, and 6 of 100 patients in the fractionated group developed cataracts, with 5-year estimated incidences of 39% and 13%, respectively. When the subgroups were considered, in the single-dose group, 3 of 28 LOW patients, and 7 of 29 HIGH patients developed cataracts, with 5-year estimated incidences of 24% and 53%, respectively; in the fractionated group, 1 of 49 LOW patients, and 5 of 51 HIGH patients developed cataracts, with 5-year estimated incidences of 4% and 22%, respectively. There was no statistically significant difference in terms of 5-year estimated cataract incidence between the patients receiving steroids and those not. The instantaneous dose rate was the only independent factor influencing the cataractogenesis. 18 refs., 5 figs., 1 tab.

  4. Instantaneous relationship between solar inertial and local vertical local horizontal attitudes

    NASA Technical Reports Server (NTRS)

    Vickery, S. A.

    1977-01-01

    The instantaneous relationship between the Solar Inertial (SI) and Local Vertical Local Horizontal (LVLH) coordinate systems is derived. A method is presented for computation of the LVLH to SI rotational transformation matrix as a function of an input LVLH attitude and the corresponding look angles to the sun. Logic is provided for conversion between LVLH and SI attitudes expressed in terms of a pitch, yaw, roll Euler sequence. Documentation is included for a program which implements the logic on the Hewlett-Packard 97 programmable calculator.

  5. Compensating for window effects in the calculation of spectrographic instantaneous bandwidth.

    PubMed

    Davidson, K L; Loughlin, P J

    2000-04-01

    Exact results derived by Cohen and Lee are used to study the distortion induced by the window in the computation of instantaneous bandwidth via the spectrogram. These concepts have been recently used in an interesting study regarding lesion-induced blood flow disturbances, where an approximation was made to compensate for the window effects. We show that this compensation is accurate for stationary signals, but becomes increasingly poorer as the signal becomes less stationary (e.g., large frequency modulations). We propose an alternative technique to reduce the window distortions, and point out the use of other time-frequency distributions that do not suffer such distortions. PMID:10763302

  6. Two attosecond pulse transient absorption spectroscopy and extraction of the instantaneous AC Stark shift in helium

    NASA Astrophysics Data System (ADS)

    Bækhøj, Jens E.; Bojer Madsen, Lars

    2016-07-01

    In two attosecond pulse absorption spectroscopy (TAPAS) the use of two attosecond XUV pulses allows the extraction of atomic and molecular quantum mechanical dipole phases from spectroscopic measurements. TAPAS relies on interference between processes that individually only include a single XUV photon, and therefore does not rely on high intensity attosecond pulses. To show the usefulness and limitations of the TAPAS method we investigate its capability of capturing the instantaneous AC Stark shift induced by a midinfrared 3200 nm pulse in the | 1{{s}}2{{p}}> state of helium.

  7. Fifth-order raman spectrum of an atomic liquid: simulation and instantaneous-normal-mode calculation

    PubMed

    Ma; Stratt

    2000-07-31

    Experimental artifacts and technical difficulties in carrying out theoretical calculations have consistently frustrated attempts to obtain the two-dimensional (5th-order) Raman spectrum of a liquid. We report here a new theoretical development: the first microscopic numerical simulation of the 5th-order Raman signal in a liquid. Comparison with an instantaneous-normal-mode treatment, a fully microscopic model which interprets liquid dynamics as arising from coherent harmonic modes, shows that the 5th-order spectrum reveals profound effects stemming from dynamical anharmonicity.

  8. Robust nonstationary jammer mitigation for GPS receivers with instantaneous frequency error tolerance

    NASA Astrophysics Data System (ADS)

    Wang, Ben; Zhang, Yimin D.; Qin, Si; Amin, Moeness G.

    2016-05-01

    In this paper, we propose a nonstationary jammer suppression method for GPS receivers when the signals are sparsely sampled. Missing data samples induce noise-like artifacts in the time-frequency (TF) distribution and ambiguity function of the received signals, which lead to reduced capability and degraded performance in jammer signature estimation and excision. In the proposed method, a data-dependent TF kernel is utilized to mitigate the artifacts and sparse reconstruction methods are then applied to obtain instantaneous frequency (IF) estimation of the jammers. In addition, an error tolerance of the IF estimate is applied is applied to achieve robust jammer suppression performance in the presence of IF estimation inaccuracy.

  9. System for reactivating catalysts

    DOEpatents

    Ginosar, Daniel M.; Thompson, David N.; Anderson, Raymond P.

    2010-03-02

    A method of reactivating a catalyst, such as a solid catalyst or a liquid catalyst is provided. The method comprises providing a catalyst that is at least partially deactivated by fouling agents. The catalyst is contacted with a fluid reactivating agent that is at or above a critical point of the fluid reactivating agent and is of sufficient density to dissolve impurities. The fluid reactivating agent reacts with at least one fouling agent, releasing the at least one fouling agent from the catalyst. The at least one fouling agent becomes dissolved in the fluid reactivating agent and is subsequently separated or removed from the fluid reactivating agent so that the fluid reactivating agent may be reused. A system for reactivating a catalyst is also disclosed.

  10. Fast instantaneous center of rotation estimation algorithm for a skied-steered robot

    NASA Astrophysics Data System (ADS)

    Kniaz, V. V.

    2015-05-01

    Skid-steered robots are widely used as mobile platforms for machine vision systems. However it is hard to achieve a stable motion of such robots along desired trajectory due to an unpredictable wheel slip. It is possible to compensate the unpredictable wheel slip and stabilize the motion of the robot using visual odometry. This paper presents a fast optical flow based algorithm for estimation of instantaneous center of rotation, angular and longitudinal speed of the robot. The proposed algorithm is based on Horn-Schunck variational optical flow estimation method. The instantaneous center of rotation and motion of the robot is estimated by back projection of optical flow field to the ground surface. The developed algorithm was tested using skid-steered mobile robot. The robot is based on a mobile platform that includes two pairs of differential driven motors and a motor controller. Monocular visual odometry system consisting of a singleboard computer and a low cost webcam is mounted on the mobile platform. A state-space model of the robot was derived using standard black-box system identification. The input (commands) and the output (motion) were recorded using a dedicated external motion capture system. The obtained model was used to control the robot without visual odometry data. The paper is concluded with the algorithm quality estimation by comparison of the trajectories estimated by the algorithm with the data from motion capture system.

  11. New thermal wave aspects on burn evaluation of skin subjected to instantaneous heating.

    PubMed

    Liu, J; Chen, X; Xu, L X

    1999-04-01

    Comparative studies on the well-known Pennes' equation and the newly developed thermal wave model of bioheat transfer (TWMBT) were performed to investigate the wave like behaviors of bioheat transfer occurred in thermal injury of biological bodies. The one-dimensional TWMBT in a finite medium was solved using separation of variables and the analytical solution showed distinctive wave behaviors of bioheat transfer in skin subjected to instantaneous heating. The finite difference method was used to simulate and study practical problems involved in burn injuries in which skin was stratified as three layers with various thermal physical properties. Deviations between the TWMBT and the traditional Pennes' equation imply that, for high flux heating with extremely short duration (i.e., flash fire), the TWMBT which accounts for finite thermal wave propagation may provide realistic predictions on burn evaluation. A general heat flux criterion has been established to determine when the thermal wave propagation dominates the principal heat transfer process and the TWMBT can be used for tissue temperature prediction and burn evaluation. A preliminary interpretation on the mechanisms of the wave like behaviors of heat transfer in living tissues was conducted. The application of thermal wave theory can also be possibly extended to other medical problems which involve instantaneous heating or cooling.

  12. Instantaneous x-ray radiation energy from laser produced polystyrene plasmas for shock ignition conditions

    SciTech Connect

    Shang, Wanli; Wei, Huiyue; Li, Zhichao; Yi, Rongqing; Zhu, Tuo; Song, Tianmin; Huang, Chengwu; Yang, Jiamin

    2013-10-15

    Laser target energy coupling mechanism is crucial in the shock ignition (SI) scheme, and x-ray radiation energy is a non-negligible portion of the laser produced plasma energy. To evaluate the x-ray radiation energy amount at conditions relevant to SI scheme, instantaneous x-ray radiation energy is investigated experimentally with continuum phase plates smoothed lasers irradiating layer polystyrene targets. Comparative laser pulses without and with shock spike are employed. With the measured x-ray angular distribution, full space x-ray radiation energy and conversion efficiency are observed. Instantaneous scaling law of x-ray conversion efficiency is obtained as a function of laser intensity and time. It should be pointed out that the scaling law is available for any laser pulse shape and intensity, with which irradiates polystyrene planar target with intensity from 2 × 10{sup 14} to 1.8 × 10{sup 15} W/cm{sup 2}. Numerical analysis of the laser energy transformation is performed, and the simulation results agree with the experimental data.

  13. Instantaneous phase shift of annual subsurface temperature cycles derived by the Hilbert-Huang transform

    NASA Astrophysics Data System (ADS)

    Sun, Yang-Yi; Chen, Chieh-Hung; Liu, Jann-Yenq; Wang, Chung-Ho; Chen, Deng-Lung

    2015-03-01

    This study uses the Hilbert-Huang transform to compute the instantaneous (daily) phase shift between temperature signals at the ground surface and at a depth of 5 m. This approach is not restricted to the stationary harmonic surface temperature assumptions invoked by analytical solutions. The annual cycles are extracted from the ground surface temperatures and the shallow subsurface temperatures at 5 m depth recorded at the Hualien (23.98°N, 121.61°E) and Ilan (24.77°N, 121.75°E) meteorology stations of Central Weather Bureau in Taiwan from 1952 to 2008. Significant reductions in the phase shift and increases in the estimated thermal diffusivity from 1980s to 1990s are found and suggest that the recent warming of the Pacific Decadal Oscillation may affect heat transport in the subsurface environment. The marginal spectra of the instantaneous phase shifts and the precipitation intensity records at Hualien and Ilan reveal that precipitation may play a role in the evolution of seasonal variation in shallow subsurface heat transport.

  14. A method to account for variation of average compressor inlet pressure during instantaneous distortion analyses

    NASA Technical Reports Server (NTRS)

    Burstadt, P. L.; Wenzel, L. M.

    1976-01-01

    Instantaneous distortion analyses compare a time-varying value of an index (or 'surge margin used up') with a critical level (or 'available surge margin' of the compressor) to determine inlet-engine compatibility. Unless freestream conditions or propulsion system controls are changing, it is generally assumed that the available surge margin of the compressor is accurately determined from the steady-state operating point. Results are presented which show that variations of average compressor inlet pressure may occur without changes in freestream conditions or propulsion system controls. The volume dynamics of the compressor will cause these pressure variations to be attenuated and delayed by the time they reach the exit. This will cause the compressor pressure ratio (and available surge margin) to vary with time. A method is presented to calculate the available surge margin as a function of time and incorporate it into an instantaneous distortion analysis. Results show that inlet pressure variations which cause only a small change at the compressor exit can cause a significant variation in the available surge margin.

  15. Joint location, inventory, and preservation decisions for non-instantaneous deterioration items under delay in payments

    NASA Astrophysics Data System (ADS)

    Tsao, Yu-Chung

    2016-02-01

    This study models a joint location, inventory and preservation decision-making problem for non-instantaneous deteriorating items under delay in payments. An outside supplier provides a credit period to the wholesaler which has a distribution system with distribution centres (DCs). The non-instantaneous deteriorating means no deterioration occurs in the earlier stage, which is very useful for items such as fresh food and fruits. This paper also considers that the deteriorating rate will decrease and the reservation cost will increase as the preservation effort increases. Therefore, how much preservation effort should be made is a crucial decision. The objective of this paper is to determine the optimal locations and number of DCs, the optimal replenishment cycle time at DCs, and the optimal preservation effort simultaneously such that the total network profit is maximised. The problem is formulated as piecewise nonlinear functions and has three different cases. Algorithms based on piecewise nonlinear optimisation are provided to solve the joint location and inventory problem for all cases. Computational analysis illustrates the solution procedures and the impacts of the related parameters on decisions and profits. The results of this study can serve as references for business managers or administrators.

  16. Preliminary verification of instantaneous air temperature estimation for clear sky conditions based on SEBAL

    NASA Astrophysics Data System (ADS)

    Zhu, Shanyou; Zhou, Chuxuan; Zhang, Guixin; Zhang, Hailong; Hua, Junwei

    2016-03-01

    Spatially distributed near surface air temperature at the height of 2 m is an important input parameter for the land surface models. It is of great significance in both theoretical research and practical applications to retrieve instantaneous air temperature data from remote sensing observations. An approach based on Surface Energy Balance Algorithm for Land (SEBAL) to retrieve air temperature under clear sky conditions is presented. Taking the meteorological measurement data at one station as the reference and remotely sensed data as the model input, the research estimates the air temperature by using an iterative computation. The method was applied to the area of Jiangsu province for nine scenes by using MODIS data products, as well as part of Fujian province, China based on four scenes of Landsat 8 imagery. Comparing the air temperature estimated from the proposed method with that of the meteorological station measurement, results show that the root mean square error is 1.7 and 2.6 °C at 1000 and 30 m spatial resolution respectively. Sensitivity analysis of influencing factors reveals that land surface temperature is the most sensitive to the estimation precision. Research results indicate that the method has great potentiality to be used to estimate instantaneous air temperature distribution under clear sky conditions.

  17. Simulation of the interaction between muscle fiber conduction velocity and instantaneous firing rate.

    PubMed

    Fortune, Emma; Lowery, Madeleine M

    2011-01-01

    In this study, the relationships between the early and late afterpotentials and velocity and amplitude recovery functions (VRF and ARF) in skeletal muscle were examined using model simulation. A mathematical model of the muscle fiber action potential, that incorporated a tubular slow potassium conductance, was developed and used to simulate muscle fiber action potentials at a range of interpulse intervals. The slow potassium conductance produced an afterhyperpolarization which resulted in supernormal action potential conduction velocity and amplitude for interpulse intervals>7 ms. Increasing the number of conditioning stimuli caused a further increase in conduction velocity and amplitude, and an additional phase of supernormality, with a peak at approximately 100 ms. Positive correlations between instantaneous firing rate and both conduction velocity and amplitude were also observed during simulation of repetitive stimulation of the muscle fiber. The relationships were eliminated when the slow potassium conductance channel was removed from the model. The results suggest that an afterhyperpolarization, possibly due to a slow tubular potassium conductance, could cause the VRF and ARF observed in muscle. They additionally suggest that the positive correlations between instantaneous firing rate, conduction velocity, and amplitude are directly related to the VRF and ARF. PMID:20848314

  18. [Real time diagnostics of instantaneous temperature of combustion and explosion process by modern spectroscopy].

    PubMed

    Zhou, Xue-tie; Wang, Jun-de; Li, Yan; Liu, Da-bing

    2003-04-01

    The combustion temperature is one of the important parameters to express flame combustion and explosion characteristics. It will effectively guide the design and manufacture of new model explosives, industrial explosive materials, and weapons. The recent developments and applications of real time diagnostics of instantaneous temperature of combustion and explosion processes by modern spectroscopic methods, such as atomic absorption-emission method, atomic emission two-line spectroscopy, atomic emission multiline spectroscopy, molecular rotation-vibration spectroscopy, coherent anti-stokes Raman scattering (CARS) and plane laser-induced fluorescence (PLIF), were reviewed in this paper. The maximum time resolution of atomic absorption-emission method is 25 microseconds. The time resolution of atomic emission two-line spectroscopy can reach 0.1 microsecond. These two methods can completely suit the need of real time and instantaneous temperature diagnostics of violent explosion and flame combustion. Other methods will also provide new effective research methods for the processes and characteristics of combustion, flame and explosion. PMID:12961909

  19. Instantaneous stimulus paradigm: cortical network and dynamics of figure-ground organization

    NASA Astrophysics Data System (ADS)

    Likova, Lora T.; Tyler, Christopher W.

    2007-02-01

    To reveal the cortical network underlying figure/ground perception and to understand its neural dynamics, we developed a novel paradigm that creates distinct and prolonged percepts of spatial structures by instantaneous refreshes in random dot fields. Three different forms of spatial configuration were generated by: (i) updating the whole stimulus field, (ii) updating the ground region only (negative-figure), and (iii) updating the figure and ground regions in brief temporal asynchrony. FMRI responses were measured throughout the brain. As expected, activation by the homogenous whole-field update was focused onto the posterior part of the brain, but distinct networks extending beyond the occipital lobe into the parietal and frontal cortex were activated by the figure/ground and by the negativefigure configurations. The instantaneous stimulus paradigm generated a wide variety of BOLD waveforms and corresponding neural response estimates throughout the network. Such expressly different responses evoked by differential stimulation of the identical cortical regions assure that the differences could be securely attributed to the neural dynamics, not to spatial variations in the HRF. The activation pattern for figure/ground implies a widely distributed neural architecture, distinct from the control conditions. Even where activations are partially overlapping, an integrated analysis of the BOLD response properties will enable the functional specificity of the cortical areas to be distinguished.

  20. [Real time diagnostics of instantaneous temperature of combustion and explosion process by modern spectroscopy].

    PubMed

    Zhou, Xue-tie; Wang, Jun-de; Li, Yan; Liu, Da-bing

    2003-04-01

    The combustion temperature is one of the important parameters to express flame combustion and explosion characteristics. It will effectively guide the design and manufacture of new model explosives, industrial explosive materials, and weapons. The recent developments and applications of real time diagnostics of instantaneous temperature of combustion and explosion processes by modern spectroscopic methods, such as atomic absorption-emission method, atomic emission two-line spectroscopy, atomic emission multiline spectroscopy, molecular rotation-vibration spectroscopy, coherent anti-stokes Raman scattering (CARS) and plane laser-induced fluorescence (PLIF), were reviewed in this paper. The maximum time resolution of atomic absorption-emission method is 25 microseconds. The time resolution of atomic emission two-line spectroscopy can reach 0.1 microsecond. These two methods can completely suit the need of real time and instantaneous temperature diagnostics of violent explosion and flame combustion. Other methods will also provide new effective research methods for the processes and characteristics of combustion, flame and explosion.

  1. Online tracking of instantaneous frequency and amplitude of dynamical system response

    NASA Astrophysics Data System (ADS)

    Frank Pai, P.

    2010-05-01

    This paper presents a sliding-window tracking (SWT) method for accurate tracking of the instantaneous frequency and amplitude of arbitrary dynamic response by processing only three (or more) most recent data points. Teager-Kaiser algorithm (TKA) is a well-known four-point method for online tracking of frequency and amplitude. Because finite difference is used in TKA, its accuracy is easily destroyed by measurement and/or signal-processing noise. Moreover, because TKA assumes the processed signal to be a pure harmonic, any moving average in the signal can destroy the accuracy of TKA. On the other hand, because SWT uses a constant and a pair of windowed regular harmonics to fit the data and estimate the instantaneous frequency and amplitude, the influence of any moving average is eliminated. Moreover, noise filtering is an implicit capability of SWT when more than three data points are used, and this capability increases with the number of processed data points. To compare the accuracy of SWT and TKA, Hilbert-Huang transform is used to extract accurate time-varying frequencies and amplitudes by processing the whole data set without assuming the signal to be harmonic. Frequency and amplitude trackings of different amplitude- and frequency-modulated signals, vibrato in music, and nonlinear stationary and non-stationary dynamic signals are studied. Results show that SWT is more accurate, robust, and versatile than TKA for online tracking of frequency and amplitude.

  2. Method for preparing hydride configurations and reactive metal surfaces

    DOEpatents

    Silver, Gary L.

    1988-08-16

    A method for preparing highly hydrogen-reactive surfaces on metals which normally require substantial heating, high pressures, or an extended induction period, which involves pretreatment of said surfaces with either a non-oxidizing acid or hydrogen gas to form a hydrogen-bearing coating on said surfaces, and subsequently heating said coated metal in the absence of moisture and oxygen for a period sufficient to decompose said coating and cooling said metal to room temperature. Surfaces so treated will react almost instantaneously with hydrogen gas at room temperature and low pressure. The method is particularly applicable to uranium, thorium, and lanthanide metals.

  3. Myocardial mechanics in aortic and mitral valvular regurgitation: the concept of instantaneous impedance as a determinant of the performance of the intact heart

    PubMed Central

    Urschel, Charles W.; Covell, James W.; Sonnenblick, Edmund H.; Ross, John; Braunwald, Eugene

    1968-01-01

    The effects on myocardial mechanics of acute, artificial aortic and mitral regurgitation were studied in the dog to determine the manner in which the changes in load induced by valvular regurgitation alter ventricular performance. With mitral and aortic regurgitant volumes of approximately the same magnitude as the forward stroke volume, immediate increases occurred in total stroke volume, left ventricular enddiastolic pressure, and peak ejection velocity, whereas contractility remained unchanged. Although calculated myocardial fiber tension rose, the rate of decline of tension during ejection was accelerated with regurgitation due to the more rapid decrease in ventricular size. Average tension therefore decreased relative to average pressure. As a consequence of the increased fiber length and this unloading, contractile element velocity, work, and power were increased. Despite unchanged contractility of the myocardium, the ejection fraction rose with both aortic and mitral regurgitation. When regurgitant beats were compared with control beats at a constant end-diastolic volume, ventricular stroke volume, work, power, and ejection fraction, as well as contractile element velocity, work, and power consistently increased. Thus, reduction of instantaneous impedance to ejection allowed the ventricle to empty further, reducing ventricular wall tension with a resultant increase in the velocity of shortening. External energy output was increased despite unchanged contractility and diastolic fiber length. It is concluded that the impedance to ejection and myocardial fiber tension during ejection govern the velocity and extent of contractile element shortening, and hence affect stroke volume, peak aortic flow rate, and ejection fraction. The alterations of ventricular function accompanying valvular regurgitation can be explained by an evaluation of the effects of these lesions on the instantaneous impedance to left ventricular ejection. Images PMID:5641623

  4. Technical note: Comparison of instantaneous sampling and continuous observation of dairy cattle behavior in freestall housing.

    PubMed

    Chen, Jennifer M; Schütz, Karin E; Tucker, Cassandra B

    2016-10-01

    Recording behavior at fixed intervals (instantaneous sampling) can reduce labor relative to observing continuously. However, instantaneous sampling may inaccurately estimate potentially important responses, such as how frequently cows perform a behavior (i.e., the number of bouts). Our objective was to validate the use of instantaneous sampling for capturing how long and how frequently cows in freestall housing lie down or visit the feed bunk and water trough. We predicted that more frequent sampling would be needed to accurately reflect the behaviors that cows spent less time performing. In addition, we predicted that instantaneous sampling would underestimate how often cows engaged in behaviors that they frequently performed in short bouts or with short intervals between bouts, as some of these events may occur between sample intervals. Continuous video observations of 18 lactating Holstein-Friesian dairy cows were conducted for 48-h periods. Instantaneous samples (1 and 30 s, and 1, 3, 5, 10, 15, and 30 min) were generated from continuous data, with the samples recorded at 1-s intervals representing true values. Estimates from each sample interval ≥30 s were compared pairwise to true values with regression analysis. Sample intervals were considered accurate if they met 3 criteria: coefficient of determination ≥0.9 (i.e., strongly related to true values), slope=1, and intercept=0 (i.e., did not over- or underestimate true values). The amount of time cows spent lying (12.1±1.8h/24h, mean ± standard deviation) or visiting the water trough (1.1±0.8h/24h) and feed bunk (5.6±0.8h/24h) were accurately captured using sample intervals ≤30, 10, and 5 min, respectively. In addition, sample intervals ≤3 min accurately estimated the number of lying bouts (10.3±2.4 per 24h), likely because cows were recumbent for long periods (74.0±17.4 min, on average, with <6% of bouts lasting <5 min) and rarely resumed lying soon after standing up (0.4% of intervals between

  5. Epitaxial growth of γ-Al{sub 2}O{sub 3} on Ti{sub 2}AlC(0001) by reactive high-power impulse magnetron sputtering

    SciTech Connect

    Eklund, Per Frodelius, Jenny; Hultman, Lars; Lu, Jun; Magnfält, Daniel

    2014-01-15

    Al{sub 2}O{sub 3} was deposited by reactive high-power impulse magnetron sputtering at 600 °C onto pre-deposited Ti{sub 2}AlC(0001) thin films on α-Al{sub 2}O{sub 3}(0001) substrates. The Al{sub 2}O{sub 3} was deposited to a thickness of 65 nm and formed an adherent layer of epitaxial γ-Al{sub 2}O{sub 3}(111) as shown by transmission electron microscopy. The demonstration of epitaxial growth of γ-Al{sub 2}O{sub 3} on Ti{sub 2}AlC(0001) open prospects for growth of crystalline alumina as protective coatings on Ti{sub 2}AlC and related nanolaminated materials. The crystallographic orientation relationships are γ-Al{sub 2}O{sub 3}(111)//Ti{sub 2}AlC(0001) (out-of-plane) and γ- Al {sub 2}O{sub 3}(22{sup ¯}0)// Ti {sub 2} AlC (112{sup ¯}0) (in-plane) as determined by electron diffraction. Annealing in vacuum at 900 °C resulted in partial decomposition of the Ti{sub 2}AlC by depletion of Al and diffusion into and through the γ-Al{sub 2}O{sub 3} layer.

  6. Optimal reactive planning with security constraints

    SciTech Connect

    Thomas, W.R.; Cheng, D.T.Y.; Dixon, A.M.; Thorp, J.D.; Dunnett, R.M.; Schaff, G.

    1995-12-31

    The National Grid Company (NGC) of England and Wales has developed a computer program, SCORPION, to help system planners optimize the location and size of new reactive compensation plant on the transmission system. The reactive power requirements of the NGC system have risen as a result of increased power flows and the shorter timescale on which power stations are commissioned and withdrawn from service. In view of the high costs involved, it is important that reactive compensation be installed as economically as possible, without compromising security. Traditional methods based on iterative use of a load flow program are labor intensive and subjective. SCORPION determines a near-optimal pattern of new reactive sources which are required to satisfy voltage constraints for normal and contingent states of operation of the transmission system. The algorithm processes the system states sequentially, instead of optimizing all of them simultaneously. This allows a large number of system states to be considered with an acceptable run time and computer memory requirement. Installed reactive sources are treated as continuous, rather than discrete, variables. However, the program has a restart facility which enables the user to add realistically sized reactive sources explicitly and thereby work towards a realizable solution to the planning problem.

  7. Educational Electrical Appliance Power Meter and Logger

    ERIC Educational Resources Information Center

    Nunn, John

    2013-01-01

    The principles behind two different designs of inductive power meter are presented. They both make use of the microphone input of a computer which, together with a custom-written program, can record the instantaneous power of a domestic electrical appliance. The device can be built quickly and can be calibrated with reference to a known power…

  8. Evaluating the design of an Earth Radiation Budget Instrument with systen simulations. Part 1: Instantaneous estimates

    NASA Technical Reports Server (NTRS)

    Stowe, Larry; Ardanuy, Philip; Hucek, Richard; Abel, Peter; Jacobowitz, Herbert

    1993-01-01

    A set of system simulations has been performed to evaluate candidate scanner designs for an Earth Radiation Budget Instrument (ERBI) for the Earth Observing System (EOS) of the late 1990s. Five different instruments are considered: (1) the Active Cavity Array (ACA), (2) the Clouds and Earth's Radiant Energy System-Instrument (CERES-I), (3) the Conically Scanning Radiometer (CSR), (4) the Earth Radiation Budget Experiment Cross-Track Scanner (ERBE), and (5) the Nimbus-7 Biaxial Scanner (N7). Errors in instantaneous, top-of-the-atmosphere (TOA) satellite flux estimates are assumed to arise from two measurement problems: the sampling of space over a given geographic domain, and sampling in angle about a given spatial location. When angular sampling errors vanish due to the application of correct angular dependence models (ADMs) during inversion, the accuracy of each scanner design is determined by the instrument's ability to map the TOA radiance field in a uniform manner. In this regard, the instruments containing a cross-track scanning component (CERES-I and ERBE) do best. As errors in ADMs are encountered, cross-track instruments incur angular sampling errors more rapidly than biaxial instruments (N7, ACA, and CSR) and eventually overtake the biaxial designs in their total error amounts. A latitude bias (north-south error gradient) in the ADM error of cross-track instruments also exists. This would be objectionable when ADM errors are systematic over large areas of the globe. For instantaneous errors, however, cross-track scanners outperform biaxial or conical scanners for 2.5 deg latitude x 2.5 deg longitude target areas, providing that the ADM error is less than or equal to 30%. A key issue is the amount of systematic ADM error (departures from the mean models) that is present at the 2.5 deg resolution of the ERBE target areas. If this error is less than 30%, then the CERES-I, ERBE, and CSR, in order of increasing error, provide the most accurate instantaneous

  9. Comparisons of Instantaneous TRMM Ground Validation and Satellite Rain Rate Estimates at Different Spatial Scales

    NASA Technical Reports Server (NTRS)

    Wolff, David B.; Fisher, Brad L.

    2007-01-01

    This study provides a comprehensive inter-comparison of instantaneous rain estimates from the two rain sensors aboard the TRMM satellite with ground data from thee designated Ground Validation Sites: Kwajalein Atoll, Melbourne, Florida and Houston, Texas. The satellite rain retrievals utilize rain observations collected by the TRMM microwave imager (TMI) and the Precipitation Radar (PR) aboard the TRMM satellite. Three standard instantaneous rain products are the generated from the rain information retrieved from the satellite using the TMI, PR and Combined (COM) rain algorithms. The validation data set used in this study was obtained from instantaneous rain rates inferred from ground radars at each GV site. The first comparison used 0.5(sup 0) x 0.5(sup 0) gridded data obtained from the TRMM 3668 product, and similarly gridded GV data obtained from ground-based radars. The comparisons were made at the same spatial and temporal scales in order to eliminate sampling biases in our comparisons. An additional comparison was made by averaging rain rates for the PR, COM and GV estimates within each TMI footprint (approx. 150 square kilometers). For this analysis, unconditional mean rain rates from PR, COM and GV estimates were calculated within each TMI footprint that was observed within 100 km from the respective GV site (and also observed by the PR). This analysis used all the available matching data from the period 1999-2004, representing a sample size of over 50,000 footprints for each site. In the first analysis our results showed that all of the respective rain rate estimates agree well, with some exceptions. The more salient differences were associated with heavy rain events in which one or more of the algorithms failed to properly retrieve these extreme events. Also, it appears that there is a preferred mode of precipitation for TMI rain rates at or near 2 mm per hour over the ocean. This mode was noted over ocean areas of Melbourne, Florida and Kwajalein

  10. Carbon nanofiber multiplexed array and Wireless Instantaneous Neurotransmitter Concentration Sensor for simultaneous detection of dissolved oxygen and dopamine

    PubMed Central

    Marsh, Michael P.; Koehne, Jessica E.; Andrews, Russell J.; Meyyappan, M.; Bennet, Kevin E.; Lee, Kendall H.

    2014-01-01

    Purpose While the mechanism of Deep Brain Stimulation (DBS) remains poorly understood, previous studies have shown that it evokes release of neurochemicals and induces activation of functional magnetic resonance imaging (fMRI) blood oxygen level-dependent signal in distinct areas of the brain. Therefore, the main purpose of this paper is to demonstrate the capabilities of the Wireless Instantaneous Neurotransmitter Concentration Sensor system (WINCS) in conjunction with a carbon nanofiber (CNF) multiplexed array electrode as a powerful tool for elucidating the mechanism of DBS through the simultaneous detection of multiple bioactive-molecules. Methods Patterned CNF nanoelectrode arrays were prepared on a 4-inch silicon wafer where each device consists of 3 × 3 electrode pads, 200 μm square, that contain CNFs spaced at 1μm intervals. The multiplexed carbon nanofiber CNF electrodes were integrated with WINCS to detect mixtures of dopamine (DA) and oxygen (O2) using fast scan cyclic voltammetry (FSCV) in vitro. Results First, simultaneous detection of O2 at two spatially different locations, 200 um apart, was demonstrated. Second, simultaneous detection of both O2 and DA at two spatially different locations, using two different decoupled waveforms was demonstrated. Third, controlled studies demonstrated that the waveform must be interleaved to avoid electrode crosstalk artifacts in the acquired data. Conclusions Multiplexed CNF nanoelectrode arrays for electrochemical detection of neurotransmitters show promise for the detection of multiple analytes with the application of time independent decoupled waveforms. Electrochemistry on CNF electrodes may be helpful in elucidating the mechanism of DBS, and may also provide the precision and sensitivity required for future applications in feedback modulated DBS neural control systems. PMID:24688800

  11. Dietary Magnesium Is Positively Associated With Skeletal Muscle Power and Indices of Muscle Mass and May Attenuate the Association Between Circulating C-Reactive Protein and Muscle Mass in Women.

    PubMed

    Welch, Ailsa A; Kelaiditi, Eirini; Jennings, Amy; Steves, Claire J; Spector, Tim D; MacGregor, Alexander

    2016-02-01

    Age-related loss of skeletal muscle mass and strength are risk factors for sarcopenia, osteoporosis, falls, fractures, frailty, and mortality. Dietary magnesium (Mg) could play a role in prevention of age-related loss of skeletal muscle mass, power, and strength directly through physiological mechanisms or indirectly through an impact on chronic low-grade inflammation, itself a risk factor for loss of skeletal muscle mass and strength. In a cross-sectional study of 2570 women aged 18 to 79 years, we examined associations between intakes of Mg, estimated using a food-frequency questionnaire (FFQ), dual-energy X-ray absorptiometry (DXA)-derived measures of muscle mass (fat-free mass as a percentage of body weight [FFM%], fat-free mass index [FFMI, kg/m(2)]), leg explosive power (LEP), and grip strength (n = 949 only). We also examined associations between circulating hs-CRP (C-reactive protein) and muscle mass and LEP, and explored the potential attenuation of these relationships by Mg. We compared our findings with those of age and protein intake. Endpoints were calculated by quintile of Mg and adjusted for relevant confounders. Significant positive associations were found between a higher Mg and indices of skeletal muscle mass and LEP, and also with hs-CRP, after adjustment for covariates. Contrasting extreme quintiles of Mg intake showed differences of 2.6% for FFM% (p trend < 0.001), 0.4 kg/m(2) for FFMI (p trend = 0.005), and 19.6 watts/kg for LEP (p trend < 0.001). Compared with protein, these positive associations were 7 times greater for FFM% and 2.5 times greater for LEP. We also found that higher hs-CRP was negatively associated with skeletal muscle mass and, in statistical modeling, that a higher dietary Mg attenuated this negative relationship by 6.5%, with greater attenuation in women older than 50 years. No association was found between Mg and grip strength. Our results suggest that dietary magnesium may aid conservation of age-related loss of skeletal

  12. Instantaneous, phase-averaged, and time-averaged pressure from particle image velocimetry

    NASA Astrophysics Data System (ADS)

    de Kat, Roeland

    2015-11-01

    Recent work on pressure determination using velocity data from particle image velocimetry (PIV) resulted in approaches that allow for instantaneous and volumetric pressure determination. However, applying these approaches is not always feasible (e.g. due to resolution, access, or other constraints) or desired. In those cases pressure determination approaches using phase-averaged or time-averaged velocity provide an alternative. To assess the performance of these different pressure determination approaches against one another, they are applied to a single data set and their results are compared with each other and with surface pressure measurements. For this assessment, the data set of a flow around a square cylinder (de Kat & van Oudheusden, 2012, Exp. Fluids 52:1089-1106) is used. RdK is supported by a Leverhulme Trust Early Career Fellowship.

  13. Instantaneous stepped-frequency, non-linear radar part 2: experimental confirmation

    NASA Astrophysics Data System (ADS)

    Ranney, Kenneth; Mazzaro, Gregory; Gallagher, Kyle; Martone, Anthony; Sherbondy, Kelly; Narayanan, Ram

    2016-05-01

    Last year, we presented the theory behind "instantaneous stepped-frequency, non-linear radar". We demonstrated through simulation that certain devices (when interrogated by a multi-tone transmit signal) could be expected to produce a multi-tone output signal near harmonics of the transmitted tones. This hypothesized non-linear (multitone) response was then shown to be suitable for pulse compression via standard stepped-frequency processing techniques. At that time, however, we did not have measured data to support the theoretical and simulated results. We now present laboratory measurements confirming our initial hypotheses. We begin with a brief description of the experimental system, and then describe the data collection exercise. Finally, we present measured data demonstrating the accurate ranging of a non-linear target.

  14. Instantaneous fluxless bonding of Au with Pb-Sn solder in ambient atmosphere

    SciTech Connect

    Lee, T.K.; Zhang, Sam; Wong, C.C.; Tan, A.C.

    2005-08-01

    A fluxless bonding technique has been developed as a method of flip-chip bonding for microelectronic packaging. The fluxless bonding technique can be achieved instantaneously in an ambient environment between metallic stud bumps and predefined molten solder. This paper describes the mechanics of the bonding action and verifies the effectiveness of this bonding method through wetting balance tests and scanning electron microscope and energy dispersive x-ray analysis. This technique has been demonstrated by using a gold stud bump to break the tin oxide layer over molten solder. This allows for a fast, solid liquid interdiffusion between gold (Au) and the fresh molten eutectic lead-tin (Pb-Sn) solder for joint formation during solidification. This bonding method has been successfully tested with 130-{mu}m-pitch flip-chip bond pads on a joint-in-via flex substrate architecture.

  15. A parametric approach for the estimation of the instantaneous speed of rotating machinery

    NASA Astrophysics Data System (ADS)

    Rodopoulos, Konstantinos; Yiakopoulos, Christos; Antoniadis, Ioannis

    2014-02-01

    A parametric method is proposed for the estimation of the instantaneous speed of rotating machines. The method belongs typically to the class of eigenvalue based parametric signal processing methods. The major advantage of parametric methods over frequency domain or time-frequency domain based methods, is their increased resolution and their reduced computational cost. Moreover, advantages of eigenvalue based methods over other parametric methods include their robustness to noise. Sensitivity analysis for the key parameters of the proposed method is performed, including the sampling frequency, the signal length and the robustness to noise. The effectiveness of the method is demonstrated in vibration measurements from a test rig during start-up and run-down, as well as during variations of the speed of a motorcycle engine. Compared to the Hilbert Transform and to the Discrete Energy Separation Algorithm (DESA), the proposed approach exhibits a better behavior, while it simultaneously presents computational simplicity, being able to be implemented analytically, even online.

  16. Dynamics and instantaneous normal modes in a liquid with density anomalies.

    PubMed

    Ciamarra, M P; Sollich, P

    2015-05-20

    We investigate the relation between the dynamical features of a supercooled liquid and those of its potential energy landscape, focusing on a model liquid with density anomalies. We consider, at fixed temperature, pairs of state points with different density but the same diffusion constant and find that surprisingly they have identical dynamical features at all length and time scales. This is shown by the collapse of their mean square displacements and of their self-intermediate scattering functions at different wavevectors. We then investigate how the features of the energy landscape change with density and establish that state points with equal diffusion constant have different landscapes. In particular, we find a correlation between the fraction of instantaneous normal modes connecting different energy minima and the diffusion constant, but unlike in other systems these two quantities are not in one-to-one correspondence with each other, showing that additional landscape features must be relevant in determining the diffusion constant.

  17. Audio analysis of statistically instantaneous signals with mixed Gaussian probability distributions

    NASA Astrophysics Data System (ADS)

    Naik, Ganesh R.; Wang, Wenwu

    2012-10-01

    In this article, a novel method is proposed to measure the separation qualities of statistically instantaneous audio signals with mixed Gaussian probability distributions. This study evaluates the impact of the Probability Distribution Function (PDF) of the mixed signals on the outcomes of both sub- and super-Gaussian distributions. Different Gaussian measures are evaluated by using various spectral-distortion measures. It aims to compare the different audio mixtures from both super-Gaussian and sub-Gaussian perspectives. Extensive computer simulation confirms that the separated sources always have super-Gaussian characteristics irrespective of the PDF of the signals or mixtures. The result based on the objective measures demonstrates the effectiveness of source separation in improving the quality of the separated audio sources.

  18. Optimum instantaneous impulsive orbital injection to attain a specified asymptotic velocity vector.

    NASA Technical Reports Server (NTRS)

    Bean, W. C.

    1971-01-01

    A nalysis of the necessary conditions of Battin for instantaneous orbital injection, with consideration of the uniqueness of his solution, and of the further problem which arises in the degenerate case when radius vector and asymptotic vector are separated by 180 deg. It is shown that when the angular separation between radius vector and asymptotic velocity vector satisfies theta not equal to 180 deg, there are precisely two insertion-velocity vectors which permit attainment of the target asymptotic velocity vector, one yielding posigrade, the other retrograde motion. When theta equals to 180 deg, there is a family of insertion-velocity vectors which permit attainment of a specified asymptotic velocity vector with a unique insertion-velocity vector for every arbitrary orientation of a target unit angular momentum vector.

  19. Instantaneous phase-shifting Fizeau interferometry with high-speed pixelated phase-mask camera

    NASA Astrophysics Data System (ADS)

    Yatagai, Toyohiko; Jackin, Boaz Jessie; Ono, Akira; Kiyohara, Kosuke; Noguchi, Masato; Yoshii, Minoru; Kiyohara, Motosuke; Niwa, Hayato; Ikuo, Kazuyuki; Onuma, Takashi

    2015-08-01

    A Fizeou interferometer with instantaneous phase-shifting ability using a Wollaston prism is designed. to measure dynamic phase change of objects, a high-speed video camera of 10-5s of shutter speed is used with a pixelated phase-mask of 1024 × 1024 elements. The light source used is a laser of wavelength 532 nm which is split into orthogonal polarization states by passing through a Wollaston prism. By adjusting the tilt of the reference surface it is possible to make the reference and object beam with orthogonal polarizations states to coincide and interfere. Then the pixelated phase-mask camera calculate the phase changes and hence the optical path length difference. Vibration of speakers and turbulence of air flow were successfully measured in 7,000 frames/sec.

  20. Instantaneous altitude estimation of maneuvering target in over-the-horizon radar exploiting multipath Doppler signatures

    NASA Astrophysics Data System (ADS)

    Zhang, Yimin D.; Zhang, Jun Jason; Amin, Moeness G.; Himed, Braham

    2013-12-01

    Over-the-horizon radar systems are capable of localizing targets in range and azimuth but are unable to achieve reliable altitude estimation. Past work has shown that the time-varying Doppler signatures of micro-multipath signals provide rich information for reliable estimation of altitude changes. In this paper, we develop a new technique for the estimation of instantaneous altitude of maneuvering targets by exploiting the estimated multicomponent Doppler signatures. A key contribution of this paper is to apply effective non-stationary signal analysis techniques for estimating the time-varying Doppler signature of each individual multipath. This enables reliable target altitude estimation in an extended Kalman filter setup. The maximum a-posteriori criterion is used for the estimation of initial target states.

  1. Remoted all optical instantaneous frequency measurement system using nonlinear mixing in highly nonlinear optical fiber.

    PubMed

    Bui, Lam Anh; Mitchell, Arnan

    2013-04-01

    A novel remoted instantaneous frequency measurement system using all optical mixing is demonstrated. This system copies an input intensity modulated optical carrier using four wave mixing, delays this copy and then mixes it with the original signal, to produce an output idler tone. The intensity of this output can be used to determine the RF frequency of the input signal. This system is inherently broadband and can be easily scaled beyond 40 GHz while maintaining a DC output which greatly simplifies receiving electronics. The remoted configuration isolates the sensitive and expensive receiver hardware from the signal sources and importantly allows the system to be added to existing microwave photonic implementations without modification of the transmission module. PMID:23571944

  2. Design of a laser system for instantaneous location of a longwall shearer

    NASA Technical Reports Server (NTRS)

    Stein, R.

    1981-01-01

    Calculations and measurements for the design of a laser system for instantaneous location of a longwall shearer were made. The designs determine shearer location to approximately one foot. The roll, pitch, and yaw angles of the shearer track are determined to approximately two degrees. The first technique uses the water target system. A single silicon sensor system and three gallium arsenide laser beams are used in this technique. The second technique is based on an arrangement similar to that employed in aircraft omnidirectional position finding. The angle between two points is determined by combining information in an onmidirectional flash with a scanned, narrow beam beacon. It is concluded that this approach maximizes the signal levels.

  3. A method for computing instantaneous downtrack error from TDRS Doppler residuals

    NASA Technical Reports Server (NTRS)

    Haas, Franklin M., Jr.

    1991-01-01

    A simple method has been developed which calculates the instantaneous downtrack error in an orbiting vehicle's state vector from TDRS (Tracking and Data Relay Satellite) Doppler observation residuals. The downtrack error is expressed as a delta-time correction to the timetag of the vehicle's state vector. The method requires only a few easily obtained parameters and is easy to implement. This paper details the derivation of computing a delta-time correction from TDRS Doppler observation residuals and evaluates the method's assumptions and limitations. The results presented show that typically the method computes delta-time corrections that are less than five percent off from the true timetag error for Doppler observation residuals within twenty minutes of closest approach to the TDRS.

  4. Effects of the Coriolis force on the oil spreading in instantaneous and continuous spill

    NASA Astrophysics Data System (ADS)

    Brovchenko, Igor; Maderich, Vladimir; Jung, Kyung Tae

    2013-04-01

    The possible effects of the Coriolis force on the oil spill spreading have not yet investigated or even discussed despite the spreading time scale for large spills can be of many hours and days and releases can last days and months like in the "Ixtoc I" and "Deep Horizon" spills. Therefore, it is important to quantify possible effects of the Coriolis force on the dynamics of spreading of surface slick caused by continuous and instantaneous releases. The main goal of this work is to explore does the Coriolis force affect the oil slick spreading in gravity viscous regime. For this study a new shallow-water model for transport and spreading of slick of arbitrary shape was developed. The governing equations for oil slick are derived in shallow water approximation by means of the continuity and the momentum equations integrated over the oil layer in which the inertial terms are neglected and is assumed balance between gravity, frictional and the Coriolis forces. The oil-water friction is parameterized in frame of boundary layer theory including the Ekman layer friction. The numerical Lagrangian method based on smoothed particle dynamics is described. New similarity solutions of the model equations are obtained for unidirectional and axisymmetric spreading in gravity-viscous and gravity-viscous-rotational regimes for instantaneous and continuous releases. The results are extended for the case of continuous release in the field of currents by numerical simulation. It was shown that Coriolis term in the momentum equation can be omitted if slick thickness is much less of the laminar Ekman layer thickness. However, the Ekman friction should be retained at any thickness of slick for large times. The Ekman friction results in the essential slowdown of the spreading as well as in the deflection of the oil spreading velocity at 45o from the direction of velocity in the non-rotation case. The new most important feature of the gravity-viscous-rotational regime is appearance of the

  5. Mean and Instantaneous Axial Profile Measurements in Turbulent Couette-Poiseuille Flow

    NASA Astrophysics Data System (ADS)

    Thurlow, Ernest; Klewicki, Joseph

    1996-11-01

    Physical experiments of fully developed planar turbulent Poiseuille-Couette flow have been conducted in a recirculating gas flow facility. Poiseuille flow Reynolds numbers ranged from 1,000 to 10,000 based upon the maximum velocity, U and channel width while the upper wall velocity, W was varied between U\\over W=± 0.6. Owing to the negative wall velocities, intrusive probes could not be used. Instead, instantaneous axial profile data were acquired using Molecular Tagging Velocimetry (MTV). In these experiments, biacetyl was used as the photochemical and nitrogen as the carrier gas. Profiles of the mean velocity, U axial intensity, u^' and axial gradient intensity, (partial u\\over partial y)^' are presented. Special attention is paid to exploring the effect of the mean profile curvature on the shape and magnitude of the intensity profiles. This work is supported by the U.S. Army Dugway Proving Ground.

  6. Instantaneous stroke volume in man during lower body negative pressure /LBNP/

    NASA Technical Reports Server (NTRS)

    Loeppky, J. A.; Richards, K. L.; Greene, E. R.; Eldridge, M. W.; Hoekenga, D. E.; Venters, M. D.; Luft, U. C.

    1982-01-01

    Results of an examination of the instantaneous time course of the stroke volume (SV) and cardiac output (Q) in response to the onset and release of -50 torr lower body negative pressure (LBNP) are reported. Six male subjects were sealed into a LBNP box up to the iliac crest while being monitored by echocardiograph for centerlamina blood velocity, fluid displacement, stroke volume, heart rate, and leg volume. Particular use was made of pulsed ultrasonic Doppler velocity meters for measuring the blood velocities and flow dynamics. Measurements were made of the subjects continuously beginning from 20 sec prior to and one min after LBNP onset and release. A linear fall in the SV was observed with LBNP at 49% of the baseline value after 33 sec. A 62% drop, the lowest, was detected after 8 min of LBNP. The leg volume was inversely related to Q for the duration of the experiment.

  7. Retrograde diurnal motion of the instantaneous rotation axis observed by a large ring laser gyroscope

    NASA Astrophysics Data System (ADS)

    Tian, W.

    2016-07-01

    Ring laser gyroscope technique directly senses the Earth's instantaneous rotation pole (IRP), whose polar motion contains strong retrograde diurnal components induced by external torques due to the gravitational attraction of the Moon and Sun. The first direct measurement of this retrograde diurnal motion with three large ring lasers was reported by Schreiber et al. (J Geophys Res 109(B18):B06405, 2004). Since then many technical improvements led to a significant increase in precision and stability of ring laser gyroscopes; however, precise determination of amplitude and phase at main partial waves has not been given in the literature. In this paper, I will report on determination of the retrograde diurnal motion of the IRP at main partial waves (Oo_1, J_1, K_1, M_1, O_1, Q_1 ) by the ring laser "G", located in Wettzell, Germany, which is the most stable one amongst the currently running large ring laser gyroscopes.

  8. Instantaneous microwave frequency measurement using four-wave mixing in a chalcogenide chip

    NASA Astrophysics Data System (ADS)

    Pagani, Mattia; Vu, Khu; Choi, Duk-Yong; Madden, Steve J.; Eggleton, Benjamin J.; Marpaung, David

    2016-08-01

    We present the first instantaneous frequency measurement (IFM) system using four-wave mixing (FWM) in a compact photonic chip. We exploit the high nonlinearity of chalcogenide to achieve efficient FWM in a short 23 mm As2S3 waveguide. This reduces the measurement latency by orders of magnitude, compared to fiber-based approaches. We demonstrate the tuning of the system response to maximize measurement bandwidth (40 GHz, limited by the equipment used), or accuracy (740 MHz rms error). Additionally, we modify the previous FWM-based IFM system structure to allow for ultra-fast reconfiguration of the bandwidth and resolution of the measurement. This has the potential to become the first IFM system capable of ultra-fast accurate frequency measurement, with no compromise of bandwidth.

  9. Retarded VS instantaneous: not so conflicting views on the pairing dynamics of the extended Hubbard model

    NASA Astrophysics Data System (ADS)

    Reymbaut, A.; Fellous Asiani, M.; Fratino, L.; Charlebois, M.; Verret, S.; Sordi, G.; Sénéchal, D..; Tremblay, A.-M. S.

    While most experimental and theoretical clues lean towards a magnetic origin for the pairing mechanism of high temperature superconductors, the question of its degree of retardation in the strong correlation regime remains highly controversial [1-5]. Part of the answer to this question lies in the frequency dependence of the anomalous spectral function of doped Mott insulators. That spectral function is associated with the Gorkov function and can be extracted at finite temperature using the MaxEntAux method for analytic continuation. Using Cellular Dynamical Mean-Field Theory for the Hubbard model with nearest-neighbor repulsion, we show that the retarded contribution coming from the anomalous spectral function is accompanied by a contribution to the real part of the anomalous self-energy at infinite frequency. This contribution suggests the emergence of a ''mixed'' pairing mechanism, mostly retarded, slightly instantaneous. Supported by NSERC, CIFAR, and the Tier I Canada Research Chair.

  10. Instantaneous Non-Linear Processing by Pulse-Coupled Threshold Units

    PubMed Central

    Rotter, Stefan; Diesmann, Markus

    2010-01-01

    Contemporary theory of spiking neuronal networks is based on the linear response of the integrate-and-fire neuron model derived in the diffusion limit. We find that for non-zero synaptic weights, the response to transient inputs differs qualitatively from this approximation. The response is instantaneous rather than exhibiting low-pass characteristics, non-linearly dependent on the input amplitude, asymmetric for excitation and inhibition, and is promoted by a characteristic level of synaptic background noise. We show that at threshold the probability density of the potential drops to zero within the range of one synaptic weight and explain how this shapes the response. The novel mechanism is exhibited on the network level and is a generic property of pulse-coupled networks of threshold units. PMID:20856583

  11. Instantaneous cloud overlap statistics in the tropical area revealed by ICESat/GLAS data

    NASA Astrophysics Data System (ADS)

    Wang, Likun; Dessler, Andrew E.

    2006-08-01

    This study uses ICESat/GLAS instantaneous observations from 29 September to 18 November 2003 to investigate cloud overlap statistics between 10°S-20°N. The results show that 75.1% of profiles detect clouds: 46.5% are single layer and 28.6% multilayer clouds (cloud layers are separated by 0.5km). Using a definition of cloud type based on cloud heights and laser attenuation information, cloud overlap statistics are derived by analyzing 96.4% of the cloudy profiles. The most frequent overlap occurs between cirrus clouds and boundary layer clouds, which accounts for 31.88% of boundary clouds. 23.8% of deep convection has overlying cirrus clouds. We find that differences exist between the cloud overlap fraction from the GLAS observations and one calculated from the random overlap assumption commonly used by climate models.

  12. Displacement vector measurement using instantaneous ultrasound signal phase - multidimensional autocorrelation and doppler methods.

    PubMed

    Sumi, Chikayoshi

    2008-01-01

    Two new methods of measuring a multidimensional displacement vector using an instantaneous ultrasound signal phase are described, i.e., the multidimensional autocorrelation method (MAM) and multidimensional Doppler method (MDM). A high measurement accuracy is achieved by combining either method with the lateral Gaussian envelope cosine modulation method (LGECMM) or multidirectional synthetic aperture method (MDSAM). Measurement accuracy is evaluated using simulated noisy echo data. Both methods yield accurate measurements comparable to that of our previously developed cross-spectrum phase gradient method (MCSPGM); however, they require less computational time (the order, MDM < MAM approximate, equals MCSPGM) and would provide realtime measurements. Moreover, comparisons of LGECMM and MDSAM performed by geometrical evaluations clarifies that LGECMM has potentials to yield more accurate measurements with less computational time. Both MAM and MDM can be applied to the measurement of tissue strain, blood flow, sonar data, and other target motions.

  13. Instantaneous high-resolution focus tracking and a vibrometery system using parallel phase shift interferometry

    NASA Astrophysics Data System (ADS)

    Ney, Michael; Safrani, Avner; Abdulhlaim, Ibrahim

    2016-09-01

    High resolution fast focus tracking and vibrometery system based on parallel phase shift polarization interferometry using three detectors is presented. The basic design and algorithm are described, followed by an experimental demonstration showing sub nm resolution of different controlled motion profiles instantaneously monitored at a feedback rate of 100 kHz. The fact that the method does not rely on active optical components, potentially allows extremely high vibration rates to be measured; limited only by the detector bandwidth and sampling rate. In addition, the relatively simple design relies only on standard optical equipment, combined with the simple algorithm, makes the task of setting up a high performance vibrometry system cheap and readily available.

  14. INSTANTANEOUS STARBURST OF THE MASSIVE CLUSTERS WESTERLUND 1 AND NGC 3603 YC

    SciTech Connect

    Kudryavtseva, Natalia; Brandner, Wolfgang; Gennaro, Mario; Rochau, Boyke; Henning, Thomas; Stolte, Andrea; Andersen, Morten; Da Rio, Nicola; Tognelli, Emanuele; Hogg, David; Clark, Simon; Waters, Rens

    2012-05-10

    We present a new method to determine the age spread of resolved stellar populations in a starburst cluster. The method relies on a two-step process. In the first step, kinematic members of the cluster are identified based on multi-epoch astrometric monitoring. In the second step, a Bayesian analysis is carried out, comparing the observed photometric sequence of cluster members with sets of theoretical isochrones. When applying this methodology to optical and near-infrared high angular resolution Hubble Space Telescope (HST) and adaptive optics observations of the {approx}5 Myr old starburst cluster Westerlund 1 and {approx}2 Myr old starburst cluster NGC 3603 YC, we derive upper limits for the age spreads of 0.4 and 0.1 Myr, respectively. The results strongly suggest that star formation in these starburst clusters happened almost instantaneously.

  15. Fast instantaneous oceanic plate velocities recorded by the Cretaceous Laytonville limestone: Paleomagnetic analysis and kinematic implications

    SciTech Connect

    Tarduno, J.A.; McWilliams, M.; Sleep, N. )

    1990-09-10

    New paleomagnetic results from 101-89 Ma Laytonville Limestone of the Franciscan Central Belt melange of northern California confirm a southern hemisphere origin as first proposed by Alvarez et al. (1980). Discovery and study of new Laytonville Limestone outcrops extend the paleomagnetic record and provide a definitive determination of age, stratigraphic polarity, and hemisphere of deposition. Paleontological determinations show that five sections are presently overturned and four are presently right side up, as expected from a random distribution of nine blocks in a melange. The exact accretion time is unknown, but geologically reasonable estimates range between 70 and 50 Ma, leading to averaged estimates of poleward velocity between 30 and 14 cm/yr. The averaged values are obtained by dividing the total paleolatitude shift by the difference between magnetization and estimated accretion ages; they reflect net poleward transport over a long time interval and are minimum estimates because they record only the poleward component of motion. An instantaneous poleward velocity is recorded by the systematic inclination decrease of 160 paleomagnetic samples with respect to decreasing age over the 12 m.y. section. Conservative estimates place this minimum velocity at 15 cm/yr. The subduction of old oceanic crust at the boundary of a relatively small plate is hypothesized as a driving mechanism to explain the measured velocities. Coupled with the minimum instantaneous poleward velocities, this hypothesis suggests that the velocities of subducting plates may vary up to a factor of 5. Similar plate geometries and resultant velocities have probably existed at other times in the past, but their discovery may have been hindered by low preservation potential.

  16. Instantaneous engine frictional torque, its components and piston assembly friction. Final report

    SciTech Connect

    Nichols, F.A.; Henein, N.A.

    1992-05-01

    The overall goal of this report is to document the work done to determine the instantaneous frictional torque of internal combustion engine by using a new approach known as (P-{omega}) method developed at Wayne State University. The emphasis has been to improve the accuracy of the method, and apply it to both diesel and gasoline engines under different operating conditions. Also work included an investigation to determine the effect of using advanced materials and techniques to coat the piston rings on the instantaneous engine frictional torque and the piston assembly friction. The errors in measuring the angular velocity, {omega}, have been determined and found to be caused by variations in the divisions within one encoder, encoder-to-encoder variations, misalignment within the encoder itself and misalignment between the encoder and crankshaft. The errors in measuring the cylinder gas pressure, P, have been determined and found to be caused by transducer-to-transducer variations, zero drift, thermal stresses and lack of linearity. The ability of the (P-{omega}) method in determining the frictional torque of many engine components has been demonstrated. These components include valve train, fuel injection pump with and without fuel injection, and piston with and without different ring combinations. The emphasis in this part of the research program has been on the piston-ring assembly friction. The effects of load and other operating variables on IFT have been determined. The motoring test, which is widely used in industry to measure engine friction has been found to be inaccurate. The errors have been determined at different loads.

  17. Instantaneous Flow Structures and Opportunities for Larval Settlement: Barnacle Larvae Swim to Settle

    PubMed Central

    Granhag, Lena M.; Jonsson, Per R.

    2016-01-01

    Water flow affects settlement of marine larvae on several scales. At the smallest scale local flow regime may control the probability of adhesion to the substrate. Our aim was to mechanistically understand the transition from suspended to attached larvae in turbulent flow. Recently it was proposed that opportunities for larval settlement in turbulent boundary layers depend on time windows with suitable instantaneous flow properties. In flume flow we characterized the proportion of suitable time windows in a series of flow velocities with focus on the near-bed flow. The change in the proportion of potential settling windows with increasing free-stream velocities was compared to the proportion of temporary attachment of barnacle cypris larvae at different flow velocities. We found large instantaneous flow variations in the near-bed flow where cyprid attachment took place. The probability of temporary attachment in cyprids declined with local flow speed and this response was compatible with a settling window lasting at least 0.1 s with a maximum local flow speed of 1.9–2.4 cm s-1. Cyprids swam against the near-bed flow (negative rheotaxis) and the swimming speed (1.8 cm s-1) was close to the critical speed that permitted temporary attachment. We conclude that temporary attachment in barnacle cyprids requires upstream swimming to maintain a fixed position relative to the substrate for at least 0.1 s. This behaviour may explain the ability of barnacles to recruit to high-flow environments and give cyprids flexibility in the pre-settlement choice of substrates based on flow regime. PMID:27463968

  18. Instantaneous Flow Structures and Opportunities for Larval Settlement: Barnacle Larvae Swim to Settle.

    PubMed

    Larsson, Ann I; Granhag, Lena M; Jonsson, Per R

    2016-01-01

    Water flow affects settlement of marine larvae on several scales. At the smallest scale local flow regime may control the probability of adhesion to the substrate. Our aim was to mechanistically understand the transition from suspended to attached larvae in turbulent flow. Recently it was proposed that opportunities for larval settlement in turbulent boundary layers depend on time windows with suitable instantaneous flow properties. In flume flow we characterized the proportion of suitable time windows in a series of flow velocities with focus on the near-bed flow. The change in the proportion of potential settling windows with increasing free-stream velocities was compared to the proportion of temporary attachment of barnacle cypris larvae at different flow velocities. We found large instantaneous flow variations in the near-bed flow where cyprid attachment took place. The probability of temporary attachment in cyprids declined with local flow speed and this response was compatible with a settling window lasting at least 0.1 s with a maximum local flow speed of 1.9-2.4 cm s-1. Cyprids swam against the near-bed flow (negative rheotaxis) and the swimming speed (1.8 cm s-1) was close to the critical speed that permitted temporary attachment. We conclude that temporary attachment in barnacle cyprids requires upstream swimming to maintain a fixed position relative to the substrate for at least 0.1 s. This behaviour may explain the ability of barnacles to recruit to high-flow environments and give cyprids flexibility in the pre-settlement choice of substrates based on flow regime. PMID:27463968

  19. Phenylethynyl reactive diluents

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G. (Inventor); Jensen, Brian J. (Inventor); Hergenrother, Paul M. (Inventor)

    1995-01-01

    A composition of matter having a specified general structure is employed to terminate a nucleophilic reagent, resulting in the exclusive production of phenylethynyl terminated reactive oligomers which display unique thermal characteristics. A reactive diluent having a specified general structure is employed to decrease the melt viscosity of a phenylethynyl terminated reactive oligomer and to subsequently react with to provide a thermosetting material of enhanced density. These materials have features which make them attractive candidates for use as composite matrices and adhesives.

  20. A comparison of Legionella pneumophila occurrence in hot water tanks and instantaneous devices in domestic, nosocomial, and community environments.

    PubMed

    Martinelli, F; Caruso, A; Moschini, L; Turano, A; Scarcella, C; Speziani, F

    2000-11-01

    The aim of this study was to compare the occurrence of L. pneumophila in hot water samples from hot water tanks and instantaneous devices. Tanks and devices were all operated by heat exchangers employed in the town's district heating system. Thirty-six out of 171 (21%) hot water samples tested positive for L. pneumophila isolation, with 14.6% belonging to serogroup 1 and 6.4% to serogroups 2-14. The proportion of L. pneumophila detected in hot water reservoirs (30%) was higher than that observed in hot water instantaneous devices (6.2%). Differences in L. pneumophila isolation reflected different temperatures registered at the faucet: 60 degrees C for hot water from instantaneous devices. These data emphasize the need to control temperature in hot water distribution devices, thus inhibiting the formation of biofilm and L. pneumophila colonization.

  1. Developing economic order quantity model for non-instantaneous deteriorating items in vendor-managed inventory (VMI) system

    NASA Astrophysics Data System (ADS)

    Tat, Roya; Allah Taleizadeh, Ata; Esmaeili, Maryam

    2015-05-01

    This paper develops an economic order quantity model for non-instantaneous deteriorating items with and without shortages to investigate the performance of the vendor-managed inventory (VMI) system. This model is developed for a two-level supply chain consisting of a single supplier and single retailer with a single non-instantaneous deteriorating item. A numerical example and sensitivity analysis are provided to illustrate how increasing or reducing the related parameters change the optimal values of the decision variables of the two proposed models. The results show that VMI works better and charges lower cost in all conditions.

  2. Transverse (lateral) instantaneous force of an acoustical first-order Bessel vortex beam centered on a rigid sphere.

    PubMed

    Mitri, F G; Fellah, Z E A

    2012-01-01

    In a recent report [F.G. Mitri, Z.E.A. Fellah, Ultrasonics 51 (2011) 719-724], it has been found that the instantaneous axial force (i.e. acting along the axis of wave propagation) of a Bessel acoustic beam centered on a sphere is only determined for the fundamental order (i.e. m=0) but vanishes when the beam is of vortex type (i.e. m>0, where m is the order (or helicity) of the beam). It has also been recognized that for circularly symmetric beams (such as Bessel beams of integer order), the transverse (lateral) instantaneous force should vanish as required by symmetry. Nevertheless, in this commentary, the present analysis unexpectedly reveals the existence of a transverse instantaneous force on a rigid sphere centered on the axis of a Bessel vortex beam of unit magnitude order (i.e. |m|=1) not reported in [F.G. Mitri, Z.E.A. Fellah, Ultrasonics 51 (2011) 719-724]. The presence of the transverse instantaneous force components of a first-order Bessel vortex beam results from mathematical anti-symmetry in the surface integrals, but vanishes for the fundamental (m=0) and higher-order Bessel (vortex) beams (i.e. |m|>1). Here, closed-form solutions for the instantaneous force components are obtained and examples for the transverse components for progressive waves are computed for a fixed and a movable rigid sphere. The results show that only the dipole (n=1) mode in the scattering contributes to the instantaneous force components, as well as how the transverse instantaneous force per unit cross-sectional surface varies versus the dimensionless frequency ka (k is the wave number in the fluid medium and a is the sphere's radius), and the half-cone angle β of the beam. Moreover, the velocity of the movable sphere is evaluated based on the concept of mechanical impedance. The proposed analysis may be of interest in the analysis of transverse instantaneous forces on spherical particles for particle manipulation and rotation in drug delivery and other biomedical or

  3. Chlorella Induces Stomatal Closure via NADPH Oxidase-Dependent ROS Production and Its Effects on Instantaneous Water Use Efficiency in Vicia faba

    PubMed Central

    Li, Yan; Xu, Shan-Shan; Gao, Jing; Pan, Sha; Wang, Gen-Xuan

    2014-01-01

    Reactive oxygen species (ROS) have been established to participate in stomatal closure induced by live microbes and microbe-associated molecular patterns (MAMPs). Chlorella as a beneficial microorganism can be expected to trigger stomatal closure via ROS production. Here, we reported that Chlorella induced stomatal closure in a dose-and time-dependent manner in epidermal peels of Vicia faba. Using pharmacological methods in this work, we found that the Chlorella-induced stomatal closure was almost completely abolished by a hydrogen peroxide (H2O2) scavenger, catalase (CAT), significantly suppressed by an NADPH oxidase inhibitor, diphenylene iodonium chloride (DPI), and slightly affected by a peroxidase inhibitor, salicylhydroxamic acid (SHAM), suggesting that ROS production involved in Chlorella-induced stomatal closure is mainly mediated by DPI-sensitive NADPH oxidase. Additionally, Exogenous application of optimal concentrations of Chlorella suspension improved instantaneous water use efficiency (WUEi) in Vicia faba via a reduction in leaf transpiration rate (E) without a parallel reduction in net photosynthetic rate (Pn) assessed by gas-exchange measurements. The chlorophyll fluorescence and content analysis further demonstrated that short-term use of Chlorella did not influence plant photosynthetic reactions center. These results preliminarily reveal that Chlorella can trigger stomatal closure via NADPH oxidase-dependent ROS production in epidermal strips and improve WUEi in leave levels. PMID:24687099

  4. The moments of the breakthrough curves of instantaneously and kinetically sorbing solutes in heterogeneous geologic media: Prediction and parameter inference from field measurements

    NASA Astrophysics Data System (ADS)

    Rubin, Yoram; Cushey, Mark A.; Wilson, Amy

    1997-11-01

    This paper presents a concise methodology for estimating the moments of the breakthrough curves for tracers and reactive solutes in heterogeneous aquifers. Under some conditions these are also the temporal or travel time moments between a source and a given destination downstream. The temporal moments of tracers as well as instantaneously or kinetically sorbing solutes, characterized by linear isotherms, are expressed in terms of a few parameters which characterize the chemical reactions and the spatial distribution and correlation structure of the hydraulic conductivity. The chemical reaction parameters are assumed to be homogeneous. The estimated moments can also be made conditional to field measurements. Applications for the case of uniform mean flow are presented, but the general approach can be applied for other flow regimes such as injection-pumping well doublets. Physical and chemical nonequilibrium processes are represented by mobile-immobile domains and two-site models, respectively. The estimated temporal moments can be used for both predictive purposes as well as for interpretation of field experiments. These two objectives are pursued in this paper. A significant advantage of the solution is that it does not require the assumptions of Gaussianity or log Gaussianity of the travel times. Throughout the discussion the combined and relative effects of the mass transfer and kinetic parameters and the spatial variability of the conductivity on the travel time moments are evaluated.

  5. Instantaneous and controllable integer ambiguity resolution: review and an alternative approach

    NASA Astrophysics Data System (ADS)

    Zhang, Jingyu; Wu, Meiping; Li, Tao; Zhang, Kaidong

    2015-11-01

    In the high-precision application of Global Navigation Satellite System (GNSS), integer ambiguity resolution is the key step to realize precise positioning and attitude determination. As the necessary part of quality control, integer aperture (IA) ambiguity resolution provides the theoretical and practical foundation for ambiguity validation. It is mainly realized by acceptance testing. Due to the constraint of correlation between ambiguities, it is impossible to realize the controlling of failure rate according to analytical formula. Hence, the fixed failure rate approach is implemented by Monte Carlo sampling. However, due to the characteristics of Monte Carlo sampling and look-up table, we have to face the problem of a large amount of time consumption if sufficient GNSS scenarios are included in the creation of look-up table. This restricts the fixed failure rate approach to be a post process approach if a look-up table is not available. Furthermore, if not enough GNSS scenarios are considered, the table may only be valid for a specific scenario or application. Besides this, the method of creating look-up table or look-up function still needs to be designed for each specific acceptance test. To overcome these problems in determination of critical values, this contribution will propose an instantaneous and CONtrollable (iCON) IA ambiguity resolution approach for the first time. The iCON approach has the following advantages: (a) critical value of acceptance test is independently determined based on the required failure rate and GNSS model without resorting to external information such as look-up table; (b) it can be realized instantaneously for most of IA estimators which have analytical probability formulas. The stronger GNSS model, the less time consumption; (c) it provides a new viewpoint to improve the research about IA estimation. To verify these conclusions, multi-frequency and multi-GNSS simulation experiments are implemented. Those results show that IA

  6. Determination of instantaneous and daily net radiation from TM - Landsat 5 data in a subtropical watershed

    NASA Astrophysics Data System (ADS)

    da Silva, Bernardo Barbosa; Montenegro, Susana Maria Gico Lima; da Silva, Vicente de Paulo Rodrigues; da Rocha, Humberto Ribeiro; Galvíncio, Josicleda Domiciano; de Oliveira, Leidjane Maria Maciel

    2015-12-01

    Remote sensing makes it possible to identify the changes that occur on the surface of the Earth as a result of natural and/or man-made phenomena. Such changes impact on the net radiation at surface which in turn controls the Earth's climate. The present study aims to determine the impact of land use changes on net radiation at surface in a tropical watershed in Brazil, based on satellite images. The instantaneous net radiation (Rn,ins) (at the time of the satellite overpass) and the daily net radiation (Rn,24 h) were both estimated by TM - Landsat 5 images and complementary weather data. The net radiation (Rn) estimated from remote sensing data was compared to the measurements taken from two micrometeorological towers located in the study area. Most Rn,ins values were found to be between 457.4 W m-2 and 760.0 W m-2 during the months with more intense solar radiation (February, March, and November), especially in the areas with more vegetation cover (sugarcane and eucalyptus plantations and areas with woody savanna vegetation, locally called Cerradão). The months with the highest thermal and radiative contrast (June and November) were selected to show the spatial distribution of the daily (Instantaneous) Rn, which ranged from 28.0 (420) W m-2 to 98.0 (520) W m-2 in June and from 83.0 (450) W m-2 to 264.0 (800) W m-2 in November 9. The model used to calculate Rn,24 h provided values close to those taken at surface, even on days with higher cloud cover after the satellite overpass. The Mean Absolute Error (MAE), Mean Relative Error (MRE), and Root Mean Square Error (RMSE) associated with the Rn,24 h computations in the sugar cane plantation were 8.3 W m-2, 8.4%, and 10.4 W m-2, respectively, confirming the applicability and accuracy of the results. The Rn patterns registered on the woody savanna throughout the year differ very much from those found in cropped areas, particularly in sugar cane plots. This may cause an impact on the watershed climate.

  7. Three-dimensional instantaneous dynamics modeling of present-day Aegean subduction

    NASA Astrophysics Data System (ADS)

    Glerum, Anne; Thieulot, Cedric; Pranger, Casper; van Hinsbergen, Douwe; Fraters, Menno; Spakman, Wim

    2015-04-01

    The Aegean region (Eastern Mediterranean) is exemplary of the interaction between crustal tectonics, plate motion, subduction and mantle flow: African subduction underneath the region has been continuous for at least the last 100 My, leading to about 2100-2500 km of subducted lithosphere residing in the mantle (van Hinsbergen et al., 2005). During this subduction, decoupled upper continental and oceanic crust accreted into a wedge of stacked nappes. In turn, these nappes have been significantly extended, predominantly during the last 25 My, due to the retreat of the African slab relative to Eurasia (van Hinsbergen and Schmid, 2012). As a first step to better understanding the coupling of the tectonic evolution of the crust and the underlying mantle dynamics, we are developing 3-D numerical models of the instantaneous dynamics of the present-day Aegean subduction system using the finite element code ASPECT (Kronbichler et al., 2012). The instantaneous models are set up with initial slab geometries derived from tomography and realistic plate boundary configurations and incorporate the major crustal weak zones of the overriding plate. Our modeling results in predictions of flow fields and stress, strain rate and rotation rate fields for the present-day tectonic setting of the Aegean region. By comparing our various model predictions to the widely available observations, such as focal mechanisms, GPS velocities and seismic anisotropy, we aim at an improved understanding of how mantle flow, subduction morphology and possibly slab segmentation, as well as the rheological behavior of the overriding plate, control present-day tectonic deformation. We expect to show preliminary results of this comparison. Kronbichler, M., Heister, T. and Bangerth, W. (2012), High Accuracy Mantle Convection Simulation through Modern Numerical Methods, Geophysical Journal International, 191, 12-29. Van Hinsbergen, D. J. J., Hafkenscheid, E., Spakman, W., Meulenkamp, J. E. and Wortel, R. (2005

  8. [Instantaneous emission spectra of epoxypropane in the process of deflagration to detonation transition].

    PubMed

    Li, Ping; Yuan, Chang-ying; Hu, Dong; Liu, Jun-chao; Zhu-mei, Sun; Dong, Shi; Xiao, Hai-bo

    2004-07-01

    Using an intensified CCD spectroscopic detector (Princeton Instruments, ICCD PI-Max 1024 RB) which can be gated in as little as 5 ns, the synchronization of the measuring system was controlled by a digital delay generator (Stanford Research Systems, DG535), the DG535 was triggered externally by a lab-made electrical pulse generator which transformed the optical trigger signal to an electrical signal, and the light signal from the end window of an explosion shock tube was delivered by an 1 mm in diameter plastic optical fiber to the entrance slit of the spectrometer (grating of 150 g x mm(-1) , central wavelength of 550 nm). The spectrum measurement of the epoxypropane in the process of deflagration to detonation transition (DDT) was then made. The instantaneous emission spectra of epoxypropane at different time of the DDT process with an exposure time of several microseconds were acquired. Results show that at the beginning of the DDT process, the emitted light was very weak and the line spectra of atoms were observed mainly; in the middle process of the DDT, the emitted light became strong and the spectra observed consisted of line spectra of atoms, band spectra of molecules plus continuous spectrum of the thermal radiation; when the detonation was formed, the emitted light got very strong, and the spectra acquired consisted of both line spectra of atoms and band spectra of molecules superimposed on the strong continuum of the thermal radiation. PMID:15766070

  9. [Using instantaneous spectra to determine dominant species in the DDT process of epoxypropane].

    PubMed

    Li, Ping; Hu, Dong; Yuan, Chang-Ying; Dai, Song-Hui; Xiao, Hai-Bo

    2006-09-01

    After solving problems of weak light detection, the calibration of the spectral sensitivity of the measuring system, and the synchronization of the measuring system, instantaneous emission spectra of epoxypropane in the process of deflagration to detonation transition (DDT) with the exposure time of 2-8 micros and the resolution of 0. 2 nm were acquired from six different side windows of an explosion shock tube. Using the corrected spectral data, curves of the optical radiant intensity of main reaction products versus the DDT distance from the ignition point were obtained. These curves provided information about the evolution of the reaction and the products during the DDT process. Results indicate that the chemical reaction rate of the gaseous fuel and the corresponding concentrations of intermediate products increased gradually at the deflagration stage, but at the moment of deflagration to detonation transition, the reaction rate increased rapidly and the concentrations! of products increased sharply. Among these main products, concentration increments of molecule CO, and radicals CHO and OH were greater than other products, which means that CO, CHO and OH are the dominant species that affect the DDT process greatly. PMID:17112018

  10. Orthogonality-breaking sensing model based on the instantaneous Stokes vector and the Mueller calculus.

    PubMed

    Ortega-Quijano, Noé; Fade, Julien; Roche, Muriel; Parnet, François; Alouini, Mehdi

    2016-04-01

    Polarimetric sensing by orthogonality breaking has been recently proposed as an alternative technique for performing direct and fast polarimetric measurements using a specific dual-frequency-dual-polarization (DFDP) source. Based on the instantaneous Stokes-Mueller formalism to describe the high-frequency evolution of the DFDP beam intensity, we thoroughly analyze the interaction of such a beam with birefringent, dichroic, and depolarizing samples. This allows us to confirm that orthogonality breaking is produced by the sample diattenuation, whereas this technique is immune to both birefringence and diagonal depolarization. We further analyze the robustness of this technique when polarimetric sensing is performed through a birefringent waveguide, and the optimal DFDP source configuration for fiber-based endoscopic measurements is subsequently identified. Finally, we consider a stochastic depolarization model based on an ensemble of random linear diattenuators, which makes it possible to understand the progressive vanishing of the detected orthogonality-breaking signal as the spatial heterogeneity of the sample increases, thus confirming the insensitivity of this method to diagonal depolarization. The fact that the orthogonality-breaking signal is exclusively due to the sample dichroism is an advantageous feature for the precise decoupled characterization of such an anisotropic parameter in samples showing several simultaneous effects.

  11. Instantaneous angular speed monitoring of gearboxes under non-cyclic stationary load conditions

    NASA Astrophysics Data System (ADS)

    Stander, C. J.; Heyns, P. S.

    2005-07-01

    Recent developments in the condition monitoring and asset management market have led to the commercialisation of online vibration-monitoring systems. These systems are primarily utilised to monitor large mineral mining equipment such as draglines, continuous miners and hydraulic shovels. Online monitoring systems make diagnostic information continuously available for asset management, production outsourcing and maintenance alliances with equipment manufacturers. However, most online vibration-monitoring systems are based on conventional vibration-monitoring technologies, which are prone to giving false equipment deterioration warnings on gears that operate under fluctuating load conditions. A simplified mathematical model of a gear system was developed to illustrate the feasibility of monitoring the instantaneous angular speed (IAS) as a means of monitoring the condition of gears that are subjected to fluctuating load conditions. A distinction is made between cyclic stationary load modulation and non-cyclic stationary load modulation. It is shown that rotation domain averaging will suppress the modulation caused by non-cyclic stationary load conditions but will not suppress the modulation caused by cyclic stationary load conditions. An experimental investigation on a test rig indicated that the IAS of a gear shaft could be monitored with a conventional shaft encoder to indicate a deteriorating gear fault condition.

  12. [Instantaneous emission spectra of epoxypropane in the process of deflagration to detonation transition].

    PubMed

    Li, Ping; Yuan, Chang-ying; Hu, Dong; Liu, Jun-chao; Zhu-mei, Sun; Dong, Shi; Xiao, Hai-bo

    2004-07-01

    Using an intensified CCD spectroscopic detector (Princeton Instruments, ICCD PI-Max 1024 RB) which can be gated in as little as 5 ns, the synchronization of the measuring system was controlled by a digital delay generator (Stanford Research Systems, DG535), the DG535 was triggered externally by a lab-made electrical pulse generator which transformed the optical trigger signal to an electrical signal, and the light signal from the end window of an explosion shock tube was delivered by an 1 mm in diameter plastic optical fiber to the entrance slit of the spectrometer (grating of 150 g x mm(-1) , central wavelength of 550 nm). The spectrum measurement of the epoxypropane in the process of deflagration to detonation transition (DDT) was then made. The instantaneous emission spectra of epoxypropane at different time of the DDT process with an exposure time of several microseconds were acquired. Results show that at the beginning of the DDT process, the emitted light was very weak and the line spectra of atoms were observed mainly; in the middle process of the DDT, the emitted light became strong and the spectra observed consisted of line spectra of atoms, band spectra of molecules plus continuous spectrum of the thermal radiation; when the detonation was formed, the emitted light got very strong, and the spectra acquired consisted of both line spectra of atoms and band spectra of molecules superimposed on the strong continuum of the thermal radiation.

  13. [Using instantaneous spectra to determine dominant species in the DDT process of epoxypropane].

    PubMed

    Li, Ping; Hu, Dong; Yuan, Chang-Ying; Dai, Song-Hui; Xiao, Hai-Bo

    2006-09-01

    After solving problems of weak light detection, the calibration of the spectral sensitivity of the measuring system, and the synchronization of the measuring system, instantaneous emission spectra of epoxypropane in the process of deflagration to detonation transition (DDT) with the exposure time of 2-8 micros and the resolution of 0. 2 nm were acquired from six different side windows of an explosion shock tube. Using the corrected spectral data, curves of the optical radiant intensity of main reaction products versus the DDT distance from the ignition point were obtained. These curves provided information about the evolution of the reaction and the products during the DDT process. Results indicate that the chemical reaction rate of the gaseous fuel and the corresponding concentrations of intermediate products increased gradually at the deflagration stage, but at the moment of deflagration to detonation transition, the reaction rate increased rapidly and the concentrations! of products increased sharply. Among these main products, concentration increments of molecule CO, and radicals CHO and OH were greater than other products, which means that CO, CHO and OH are the dominant species that affect the DDT process greatly.

  14. General description of electromagnetic radiation processes based on instantaneous charge acceleration in ''endpoints''

    SciTech Connect

    James, Clancy W.; Falcke, Heino; Huege, Tim; Ludwig, Marianne

    2011-11-15

    We present a methodology for calculating the electromagnetic radiation from accelerated charged particles. Our formulation - the 'endpoint formulation' - combines numerous results developed in the literature in relation to radiation arising from particle acceleration using a complete, and completely general, treatment. We do this by describing particle motion via a series of discrete, instantaneous acceleration events, or 'endpoints', with each such event being treated as a source of emission. This method implicitly allows for particle creation and destruction, and is suited to direct numerical implementation in either the time or frequency domains. In this paper we demonstrate the complete generality of our method for calculating the radiated field from charged particle acceleration, and show how it reduces to the classical named radiation processes such as synchrotron, Tamm's description of Vavilov-Cherenkov, and transition radiation under appropriate limits. Using this formulation, we are immediately able to answer outstanding questions regarding the phenomenology of radio emission from ultra-high-energy particle interactions in both the earth's atmosphere and the moon. In particular, our formulation makes it apparent that the dominant emission component of the Askaryan effect (coherent radio-wave radiation from high-energy particle cascades in dense media) comes from coherent 'bremsstrahlung' from particle acceleration, rather than coherent Vavilov-Cherenkov radiation.

  15. Free Energies of Cavity and Noncavity Hydrated Electrons Near the Instantaneous Air/Water Interface.

    PubMed

    Casey, Jennifer R; Schwartz, Benjamin J; Glover, William J

    2016-08-18

    The properties of the hydrated electron at the air/water interface are computed for both a cavity and a noncavity model using mixed quantum/classical molecular dynamics simulation. We take advantage of our recently developed formalism for umbrella sampling with a restrained quantum expectation value to calculate free-energy profiles of the hydrated electron's position relative to the water surface. We show that it is critical to use an instantaneous description of the air/water interface rather than the Gibbs' dividing surface to obtain accurate potentials of mean force. We find that noncavity electrons, which prefer to encompass several water molecules, avoid the interface where water molecules are scarce. In contrast, cavity models of the hydrated electron, which prefer to expel water, have a local free-energy minimum near the interface. When the cavity electron occupies this minimum, its absorption spectrum is quite red-shifted, its binding energy is significantly lowered, and its dynamics speed up quite a bit compared with the bulk, features that have not been found by experiment. The surface activity of the electron therefore serves as a useful test of cavity versus noncavity electron solvation. PMID:27479028

  16. Edge detection in ultrasound imagery using the instantaneous coefficient of variation.

    PubMed

    Yu, Yongjian; Acton, Scott T

    2004-12-01

    The instantaneous coefficient of variation (ICOV) edge detector, based on normalized gradient and Laplacian operators, has been proposed for edge detection in ultrasound images. In this paper, the edge detection and localization performance of the ICOV-squared (ICOVS) detector are examined. First, a simplified version of the ICOVS detector, the normalized gradient magnitude squared, is scrutinized in order to reveal the statistical performance of edge detection and localization in speckled ultrasound imagery. Both the probability of detection and the probability of false alarm are evaluated for the detector. Edge localization is characterized by the position of the peak and the 3-dB width of the detector response. Then, the speckle-edge response of the ICOVS as applied to a realistic edge model is studied. Through theoretical analysis, we reveal the compensatory effects of the normalized Laplacian operator in the ICOV edge detector for edge-localization error. An ICOV-based edge-detection algorithm is implemented in which the ICOV detector is embedded in a diffusion coefficient in an anisotropic diffusion process. Experiments with real ultrasound images have shown that the proposed algorithm is effective in extracting edges in the presence of speckle. Quantitatively, the ICOVS provides a lower localization error, and qualitatively, a dramatic improvement in edge-detection performance over an existing edge-detection method for speckled imagery.

  17. Instantaneous, parameter-free methods to define a solute's hydration shell

    NASA Astrophysics Data System (ADS)

    Chatterjee, Anupam; Higham, Jonathan; Henchman, Richard H.

    2015-12-01

    A range of methods are presented to calculate a solute's hydration shell from computer simulations of dilute solutions of monatomic ions and noble gas atoms. The methods are designed to be parameter-free and instantaneous so as to make them more general, accurate, and consequently applicable to disordered systems. One method is a modified nearest-neighbor method, another considers solute-water Lennard-Jones overlap followed by hydrogen-bond rearrangement, while three methods compare various combinations of water-solute and water-water forces. The methods are tested on a series of monatomic ions and solutes and compared with the values from cutoffs in the radial distribution function, the nearest-neighbor distribution functions, and the strongest-acceptor hydrogen bond definition for anions. The Lennard-Jones overlap method and one of the force-comparison methods are found to give a hydration shell for cations which is in reasonable agreement with that using a cutoff in the radial distribution function. Further modifications would be required, though, to make them capture the neighboring water molecules of noble-gas solutes if these weakly interacting molecules are considered to constitute the hydration shell.

  18. Instantaneous, parameter-free methods to define a solute's hydration shell.

    PubMed

    Chatterjee, Anupam; Higham, Jonathan; Henchman, Richard H

    2015-12-21

    A range of methods are presented to calculate a solute's hydration shell from computer simulations of dilute solutions of monatomic ions and noble gas atoms. The methods are designed to be parameter-free and instantaneous so as to make them more general, accurate, and consequently applicable to disordered systems. One method is a modified nearest-neighbor method, another considers solute-water Lennard-Jones overlap followed by hydrogen-bond rearrangement, while three methods compare various combinations of water-solute and water-water forces. The methods are tested on a series of monatomic ions and solutes and compared with the values from cutoffs in the radial distribution function, the nearest-neighbor distribution functions, and the strongest-acceptor hydrogen bond definition for anions. The Lennard-Jones overlap method and one of the force-comparison methods are found to give a hydration shell for cations which is in reasonable agreement with that using a cutoff in the radial distribution function. Further modifications would be required, though, to make them capture the neighboring water molecules of noble-gas solutes if these weakly interacting molecules are considered to constitute the hydration shell. PMID:26696060

  19. The influence of inner hair cell loss on the instantaneous frequency of the cochlear microphonic.

    PubMed

    Chertoff, Mark E; Amani-Taleshi, Darius; Guo, Yuqing; Burkard, Robert

    2002-12-01

    The cochlear microphonic (CM) is produced by a change in standing currents during the motion of the cochlear partition. The motion of the partition and associated hair cell transduction processes are nonlinear and are reflected in the variation of the instantaneous frequency (IF) of the CM. Although the CM is dominated from receptor currents from outer hair cells (OHCs), receptor currents from inner hair cells (IHCs) may contribute to the fluctuation in the IF. In this paper we examine the influence of IHCs on the variation of the IF of the CM. A 75 mg/kg intraperitoneal (i.p.) dose of carboplatin reduced the IHC population by approximately 40%. The reduction in IHCs did not substantially affect the amplitude of the CM. The amplitude of the IF, however, was reduced at high signal levels (90 and 100 dB peak SPL). A phenomenological model of the CM indicated that the contribution of IHC receptor currents to the IF was small and that changes in OHC transducer characteristics may have a greater impact on the IF. PMID:12433400

  20. Orthogonality-breaking sensing model based on the instantaneous Stokes vector and the Mueller calculus

    NASA Astrophysics Data System (ADS)

    Ortega-Quijano, Noé; Fade, Julien; Roche, Muriel; Parnet, François; Alouini, Mehdi

    2016-04-01

    Polarimetric sensing by orthogonality breaking has been recently proposed as an alternative technique for performing direct and fast polarimetric measurements using a specific dual-frequency dual-polarization (DFDP) source. Based on the instantaneous Stokes-Mueller formalism to describe the high-frequency evolution of the DFDP beam intensity, we thoroughly analyze the interaction of such a beam with birefringent, dichroic and depolarizing samples. This allows us to confirm that orthogonality breaking is produced by the sample diattenuation, whereas this technique is immune to both birefringence and diagonal depolarization. We further analyze the robustness of this technique when polarimetric sensing is performed through a birefringent waveguide, and the optimal DFDP source configuration for fiber-based endoscopic measurements is subsequently identified. Finally, we consider a stochastic depolarization model based on an ensemble of random linear diattenuators, which makes it possible to understand the progressive vanishing of the detected orthogonality breaking signal as the spatial heterogeneity of the sample increases, thus confirming the insensitivity of this method to diagonal depolarization. The fact that the orthogonality breaking signal is exclusively due to the sample dichroism is an advantageous feature for the precise decoupled characterization of such an anisotropic parameter in samples showing several simultaneous effects.

  1. Impact of instantaneous controlled pressure drop on microstructural modification of green tea and its infusion quality.

    PubMed

    Wang, Yuefei; Xu, Ping; Feng, Liyun; Yang, Xianqiang; Qian, Lisheng

    2014-01-01

    Instantaneous controlled pressure drop (DIC) was applied to obtain a suitable cell disruption extent as a technology in green tea processing. Microstructural observations showed that DIC increased cell disruption in an even manner as reflected from loosened palisade, distorted cells, widened space between cells, disrupted and rearranged cellular membrane in tea leaves. Color difference determination supported that DIC could facilitate the release and transport of cell contents. DIC sample showed a rise in redness, over 2.5 times greater than the control after spreading naturally for 24 h. Chemical determination revealed a better infusion behavior of tea polyphenols and amino acids in green tea manufactured by DIC method both at high and low temperature. The increase in tea polyphenols content in liquor for the first brew from twisted and needle tea was about 35% and that from flat tea was about 15% in DIC method over the traditional processing. These results suggest that DIC process can be applied in green tea processing for both a traditional product and a new kind of tea capable of making with cold water.

  2. Instantaneous dynamic change detection based on three-line-array stereoscopic images of TH-1 satellite

    NASA Astrophysics Data System (ADS)

    Zheng, Tuanjie; Cheng, Jiasheng; Li, Heyuan

    2014-05-01

    TH-1 satellite loading three-line array stereoscopic camera, can scanning 3 times from different directions on the same region or target within the time for about 1 minute, conducive to regional monitoring or target instantaneous change monitoring. Based on the time difference of forward, nadir and backward images of the three-line-array camera of TH-1 Satellite, this paper gives a method to get regional dynamic change image by processing of geometric and physical consistency under the principle of photogrammetry, and to construct the model of change detection by the quantitative results of change detection under the improvement and optimization of noise filtering algorithm. The experimental results show that, by using the detection results of forward, nadir and backward images of the three-line -array camera of TH-1 Satellite, moving distance and velocity can be accurately calculated, and quantitative monitoring of topography changes can be achieved, which not only has temporal resolution, but also can't be achieved by other environmental monitoring satellites. It's significant for flood, fire, clouds, or motion detectors. TH-1 satellite is China's first generation of transmission photogrammetry satellite. With the more satellites networking operation, and higher spatial and temporal resolution, The TH satellites will play a greater role in the field of Earth observation. This article merely uses the principles of photogrammetry to consider photography deformation from different directions, and thorough study will aim at shadow and sun elevation angle, to fully realize the monitoring of changes in topography and moving targets.

  3. Instantaneous normal mode prediction for cation and anion diffusion in ionic melts

    NASA Astrophysics Data System (ADS)

    Ribeiro, M. C. C.; Madden, P. A.

    1997-05-01

    Instantaneous normal mode (INM) analysis was undertaken for several ionic melts: NaCl at six distinct thermodynamic states, and for a particular state of liquid LiCl, LiF, KF, KI, NaI, ZnCl2, and CuCl. In this Communication, we show that, in most cases, the ratio between the diffusion constants for cations (Dca) and anions (Dan) is predicted from the average frequency of the real ("stable" <ωs>) and imaginary ("unstable" <ωu>) frequency modes of the projection of the total density of states on cations and anions, respectively. The proposed relationship, Dca/Dan=(mca-1<ωu>ca<ωs>ca-2)ṡ(man-1<ωu>an<ωs>an-2)-1, where mi is the mass of a particular species, is suggested by Keyes' INM theory for diffusion [J. Chem. Phys. 101, 5081 (1994)], with the further assumption that the parameters which are related to the topology of the multidimensional potential surface are equal for cations and anions. The above equation is shown to be valid for the simple melts NaCl, LiCl, LiF, KF, KI, and NaI, but to fail for the network forming melt ZnCl2 and for CuCl, which shows fast ionic diffusion characteristics.

  4. Dual Mode NOx Sensor: Measuring Both the Accumulated Amount and Instantaneous Level at Low Concentrations

    PubMed Central

    Groß, Andrea; Beulertz, Gregor; Marr, Isabella; Kubinski, David J.; Visser, Jaco H.; Moos, Ralf

    2012-01-01

    The accumulating-type (or integrating-type) NOx sensor principle offers two operation modes to measure low levels of NOx: The direct signal gives the total amount dosed over a time interval and its derivative the instantaneous concentration. With a linear sensor response, no baseline drift, and both response times and recovery times in the range of the gas exchange time of the test bench (5 to 7 s), the integrating sensor is well suited to reliably detect low levels of NOx. Experimental results are presented demonstrating the sensor’s integrating properties for the total amount detection and its sensitivity to both NO and to NO2. We also show the correlation between the derivative of the sensor signal and the known gas concentration. The long-term detection of NOx in the sub-ppm range (e.g., for air quality measurements) is discussed. Additionally, a self-adaption of the measurement range taking advantage of the temperature dependency of the sensitivity is addressed. PMID:22736980

  5. Computation of instantaneous and time-averaged active acoustic intensity field around rotating source

    NASA Astrophysics Data System (ADS)

    Mao, Yijun; Xu, Chen; Qi, Datong

    2015-02-01

    A vector aeroacoustics method is developed to analyze the acoustic energy flow path from the rotating source. In this method, the instantaneous and time-averaged active acoustic intensity vectors are evaluated from the time-domain and frequency-domain acoustic pressure and acoustic velocity formulations, respectively. With the above method, the acoustic intensity vectors and the acoustic energy streamlines are visualized to investigate the propagation feature of the noise radiated from the monopole and dipole point sources and the rotor in subsonic rotation. The result reveals that a portion of the acoustic energy spirals many circles before moving towards the far field, and another portion of the acoustic energy firstly flows inward along the radial direction and then propagates along the axial direction. Further, an acoustic black hole exists in the plane of source rotation, from which the acoustic energy cannot escape once the acoustic energy flows into it. Moreover, by visualizing the acoustic intensity field around the rotating sources, the acoustic-absorption performance of the acoustic liner built in the casing and centerbody is discussed.

  6. Impact of instantaneous controlled pressure drop on microstructural modification of green tea and its infusion quality.

    PubMed

    Wang, Yuefei; Xu, Ping; Feng, Liyun; Yang, Xianqiang; Qian, Lisheng

    2014-01-01

    Instantaneous controlled pressure drop (DIC) was applied to obtain a suitable cell disruption extent as a technology in green tea processing. Microstructural observations showed that DIC increased cell disruption in an even manner as reflected from loosened palisade, distorted cells, widened space between cells, disrupted and rearranged cellular membrane in tea leaves. Color difference determination supported that DIC could facilitate the release and transport of cell contents. DIC sample showed a rise in redness, over 2.5 times greater than the control after spreading naturally for 24 h. Chemical determination revealed a better infusion behavior of tea polyphenols and amino acids in green tea manufactured by DIC method both at high and low temperature. The increase in tea polyphenols content in liquor for the first brew from twisted and needle tea was about 35% and that from flat tea was about 15% in DIC method over the traditional processing. These results suggest that DIC process can be applied in green tea processing for both a traditional product and a new kind of tea capable of making with cold water. PMID:24426047

  7. Instantaneous frequency-based ultrasonic temperature estimation during focused ultrasound thermal therapy.

    PubMed

    Liu, Hao-Li; Li, Meng-Lin; Shih, Tzu-Ching; Huang, Sheng-Min; Lu, I-Yeh; Lin, Deng-Yn; Lin, Shi-Ming; Ju, Kuen-Cheng

    2009-10-01

    Focused ultrasound thermal therapy relies on temperature monitoring for treatment guidance and assurance of targeting and dose control. One potential approach is to monitor temperature change through ultrasonic-backscattered signal processing. The current approach involves the detection of echo time-shifts based on cross-correlation processing from segmented radiofrequency (RF) data. In this study, we propose a novel ultrasonic temperature-measurement approach that detects changes in instantaneous frequency along the imaging beam direction. Focused ultrasound was used as the heating source, and the 1-D beamformed RF signals provided from an ultrasound imager were used to verify the proposed algorithm for temperature change estimation. For comparison, a conventional cross-correlation technique was also evaluated. Heating experiments testing tissue-mimicking phantoms and ex vivo porcine muscles were conducted. The results showed that temperature can be well estimated by the proposed algorithm in the temperature range, where the relationship of sound speed versus temperature is linear. Compared with the cross-correlation-based algorithm, the proposed new algorithm yields a six-fold increase in computational efficiency, along with comparable contrast-detection ability and precision. This new algorithm may serve as an alternative method for implementing temperature estimation into a clinical ultrasound imager for thermal therapy guidance. PMID:19643529

  8. Tree Image Growth Analysis Using the Instantaneous Phase and Frequency Modulation

    SciTech Connect

    Ramachandran, Janakiramanan; Pattichis, Marios S.; Scuderi, Louis A.; Baba, Justin S

    2011-01-01

    We propose the use of Amplitude-Modulation Frequency-Modulation (AM-FM) methods for tree growth analysis. Tree growth is modeled using phase modulation. For adapting AM-FM methods to different images, we introduce the use of fast filterbank filter coefficient computation based on piecewise linear polynomials and radial frequency magnitude estimation using integer-based Savitzky-Golay filters for derivative estimation. For a wide range of images, a simple filterbank design with only 4 channel filters is used. Filterbank specification is based on two different methods. For each input image, the FM image is estimated using dominant component analysis. A tree growthmodel is developed to characterize and depict quarterly and half-seasonal growth of trees using instantaneous phase. Qualitative evaluation of inter- and intraring reconstruction is performed on 20 aspen images and a mixture of 12 tree images of various types. Qualitative scores indicate that the results were mostly of good to excellent quality (4.4/5.0 and 4.0/5.0 for the two databases, resp.).

  9. Instantaneous, parameter-free methods to define a solute’s hydration shell

    SciTech Connect

    Chatterjee, Anupam; Higham, Jonathan; Henchman, Richard H.

    2015-12-21

    A range of methods are presented to calculate a solute’s hydration shell from computer simulations of dilute solutions of monatomic ions and noble gas atoms. The methods are designed to be parameter-free and instantaneous so as to make them more general, accurate, and consequently applicable to disordered systems. One method is a modified nearest-neighbor method, another considers solute-water Lennard-Jones overlap followed by hydrogen-bond rearrangement, while three methods compare various combinations of water-solute and water-water forces. The methods are tested on a series of monatomic ions and solutes and compared with the values from cutoffs in the radial distribution function, the nearest-neighbor distribution functions, and the strongest-acceptor hydrogen bond definition for anions. The Lennard-Jones overlap method and one of the force-comparison methods are found to give a hydration shell for cations which is in reasonable agreement with that using a cutoff in the radial distribution function. Further modifications would be required, though, to make them capture the neighboring water molecules of noble-gas solutes if these weakly interacting molecules are considered to constitute the hydration shell.

  10. Instantaneous enteric nano-encapsulation of omeprazole: pharmaceutical and pharmacological evaluation.

    PubMed

    Bendas, Ehab R; Abdelbary, Aly A

    2014-07-01

    Recently, great attention has been paid to nanocapsules. The interest of these structures is due to their promising applications as drug delivery systems. The objective of this study was to develop novel enteric coating technique based on instantaneous encapsulation of the acid-labile drug, omeprazole in innovative enteric nanocapsules. Omeprazole enteric nanocapsules were formulated by varying the type and amount of the enteric polymer. The particle size (PS), polydispersity index (PDI), zeta potential (ZP) and encapsulation efficiency (EE) values of the prepared enteric nanocapsules were determined. A full 2(1)×3(1) factorial design was used for planning and analysis of the experimental trials to select the optimized formulation. The highest desirability value was 0.7463 for formula E3 (containing 200mg hydroxypropyl methylcellulose phthalate (HPMCP)). The stability of omeprazole was reflected by the absence of the exothermal peak when the drug was encapsulated as detected by differential scanning calorimetry (DSC) thermograms. In vitro drug release study confirmed the USP specifications required to meet the key formulation characteristics of gastro-resistance. In vivo pharmacological assessment showed that the optimized nanocapsules were able to protect rat stomach against ulcer formation compared to the aqueous suspension of the drug which showed less significant protection.

  11. Rotating parallel ray omni-directional integration for instantaneous pressure reconstruction from measured pressure gradient

    NASA Astrophysics Data System (ADS)

    Liu, Xiaofeng; Siddle-Mitchell, Seth

    2015-11-01

    This paper presents a novel pressure reconstruction method featuring rotating parallel ray omni-directional integration, as an improvement over the circular virtual boundary integration method introduced by Liu and Katz (2003, 2006, 2008 and 2013) for non-intrusive instantaneous pressure measurement in incompressible flow field. Unlike the virtual boundary omni-directional integration, where the integration path is originated from a virtual circular boundary at a finite distance from the real boundary of the integration domain, the new method utilizes parallel rays, which can be viewed as being originated from a distance of infinity, as guidance for integration paths. By rotating the parallel rays, omni-directional paths with equal weights coming from all directions toward the point of interest at any location within the computation domain will be generated. In this way, the location dependence of the integration weight inherent in the old algorithm will be eliminated. By implementing this new algorithm, the accuracy of the reconstructed pressure for a synthetic rotational flow in terms of r.m.s. error from theoretical values is reduced from 1.03% to 0.30%. Improvement is further demonstrated from the comparison of the reconstructed pressure with that from the Johns Hopkins University isotropic turbulence database (JHTDB). This project is funded by the San Diego State University.

  12. Defect detection in anisotropic plates based on the instantaneous phase of signals.

    PubMed

    Prado, Vander Teixeira; Granja, Silvio Cesar Garcia; Higuti, Ricardo Tokio; Kitano, Cláudio; Martínez-Graullera, Óscar; Segura, Luis Elvira

    2015-10-01

    Anisotropic materials are widely employed in industry and engineering, and efficient nondestructive testing techniques are important to guarantee the structural integrity of the involved parts. A simple technique is proposed to detect defects in anisotropic plates using ultrasonic guided waves and arrays. The technique is based on the application of an objective threshold to a synthetic aperture image obtained from the instantaneous phase (IP) of the emitter-receiver signal combinations. In a previous work the method was evaluated for isotropic materials, and in this paper it is shown that with some considerations the technique can also be applied to anisotropic plates. These considerations, which should be taken into account in beamforming, are (1) group velocity dependence with propagation direction, and (2) elastic focusing, which results in energy concentration in some propagation directions, with the practical consequence that not all aperture signals effectively contribute to the image. When compared with conventional delay-and-sum image beamforming techniques, the proposed IP technique results in significant improvements relative to defect detection and artifacts/dead zone reduction. PMID:26470050

  13. Front-Crawl Instantaneous Velocity Estimation Using a Wearable Inertial Measurement Unit

    PubMed Central

    Dadashi, Farzin; Crettenand, Florent; Millet, Grégoire P.; Aminian, Kamiar

    2012-01-01

    Monitoring the performance is a crucial task for elite sports during both training and competition. Velocity is the key parameter of performance in swimming, but swimming performance evaluation remains immature due to the complexities of measurements in water. The purpose of this study is to use a single inertial measurement unit (IMU) to estimate front crawl velocity. Thirty swimmers, equipped with an IMU on the sacrum, each performed four different velocity trials of 25 m in ascending order. A tethered speedometer was used as the velocity measurement reference. Deployment of biomechanical constraints of front crawl locomotion and change detection framework on acceleration signal paved the way for a drift-free integration of forward acceleration using IMU to estimate the swimmers velocity. A difference of 0.6 ± 5.4 cm·s−1 on mean cycle velocity and an RMS difference of 11.3 cm·s−1 in instantaneous velocity estimation were observed between IMU and the reference. The most important contribution of the study is a new practical tool for objective evaluation of swimming performance. A single body-worn IMU provides timely feedback for coaches and sport scientists without any complicated setup or restraining the swimmer's natural technique. PMID:23201978

  14. Event synchronous sinusoidal model based on frequency-to-instantaneous frequency mapping

    NASA Astrophysics Data System (ADS)

    Zolfaghari, Parham; Banno, Hideki; Itakura, Fumitada; Kawahara, Hideki

    2002-05-01

    We describe a glottal event synchronous sinusoidal model for speech analysis and synthesis. The sinusoidal components are event synchronously estimated using a mapping from linearly spaced filter center frequencies to the instantaneous frequencies of the filter outputs. Frequency domain fixed points of this mapping correspond to the constituent sinusoidal components of the input signal. A robust technique based on a wavelet representation of this fixed points model is used for fundamental frequency extraction as used in STRAIGHT [Kawahara et al., IEICE (1999)]. The method for event detection and characterization is based on group delay and similar fixed point analysis. This method enables the detection of precise timing and spread of speech events such as vocal fold closure. A trajectory continuation scheme is also applied to the extracted sinusoidal components. The proposed model is capable of high-quality speech synthesis using the overlap-add synthesis method and is also applicable to other sound sources. System evaluation results using spectral distortion measures and mean opinion scores will be reported. A comparison with the fixed frame-rate sinusoidal models will be given.

  15. Damping efficiency of the Tchamwa-Wielgosz explicit dissipative scheme under instantaneous loading conditions

    NASA Astrophysics Data System (ADS)

    Mahéo, Laurent; Grolleau, Vincent; Rio, Gérard

    2009-11-01

    To deal with dynamic and wave propagation problems, dissipative methods are often used to reduce the effects of the spurious oscillations induced by the spatial and time discretization procedures. Among the many dissipative methods available, the Tchamwa-Wielgosz (TW) explicit scheme is particularly useful because it damps out the spurious oscillations occurring in the highest frequency domain. The theoretical study performed here shows that the TW scheme is decentered to the right, and that the damping can be attributed to a nodal displacement perturbation. The FEM study carried out using instantaneous 1-D and 3-D compression loads shows that it is useful to display the damping versus the number of time steps in order to obtain a constant damping efficiency whatever the size of element used for the regular meshing. A study on the responses obtained with irregular meshes shows that the TW scheme is only slightly sensitive to the spatial discretization procedure used. To cite this article: L. Mahéo et al., C. R. Mecanique 337 (2009).

  16. Line laser lock-in thermography for instantaneous imaging of cracks in semiconductor chips

    NASA Astrophysics Data System (ADS)

    An, Yun-Kyu; Yang, Jinyeol; Hwang, Soonkyu; Sohn, Hoon

    2015-10-01

    This study proposes a new line laser lock-in thermography (LLT) technique for instantaneous inspection of surface cracks in semiconductor chips. First, a new line LLT system is developed by integrating a line scanning laser source, a high-speed infrared (IR) camera with a close-up lens, and a control computer. The proposed line LLT system scans a line laser beam onto a target semiconductor chip surface and measures the corresponding thermal wave propagation using an IR camera. A novel baseline-free crack visualization algorithm is then proposed so that heat blocking phenomena caused by crack formation can be automatically visualized and diagnosed without relying on the baseline data obtained from the pristine condition of a target semiconductor chip. The proposed inspection technique offers the following advantages over the existing semiconductor chip inspection techniques: (1) inspection is performed in a noncontact, nondestructive and nonintrusive manner; (2) the crack diagnosis can be accomplished using only current-state thermal images and thus past thermal images are unnecessary; and (3) crack detectability is significantly enhanced by achieving high spatial resolution for thermal images and removing undesired noise components from the measured thermal images. Validation tests are performed on two different types of semiconductor die chips with real micro-cracks produced during actual fabrication processes. The experiments demonstrate that the proposed line LLT technique can successfully visualize and detect semiconductor chip cracks with width of 28-54 μm.

  17. Instantaneous reference-free crack detection based on polarization characteristics of piezoelectric materials

    NASA Astrophysics Data System (ADS)

    Kim, Seung Bum; Sohn, Hoon

    2007-12-01

    A new methodology of guided-wave-based nondestructive testing (NDT) is developed to detect crack damage in a thin metal structure without using prior baseline data or a predetermined decision boundary. In conventional guided-wave-based techniques, damage is often identified by comparing the 'current' data obtained from a potentially damaged condition of a structure with the 'past' baseline data collected at the pristine condition of the structure. However, it has been reported that this type of pattern comparison with the baseline data can lead to increased false alarms due to its susceptibility to varying operational and environmental conditions of the structure. To develop a more robust damage diagnosis technique, a new concept of NDT is conceived so that cracks can be detected even when the system being monitored is subjected to changing operational and environmental conditions. The proposed NDT technique utilizes the polarization characteristics of the piezoelectric wafers attached on both sides of the thin metal structure. Crack formation creates Lamb wave mode conversion due to a sudden change in the thickness of the structure. Then, the proposed technique instantly detects the appearance of the crack by extracting this mode conversion from the measured Lamb waves, and the threshold value from damage classification is also obtained only from the current dataset. Numerical and experimental results are presented to demonstrate the applicability of the proposed technique to instantaneous crack detection.

  18. Reactive Leidenfrost droplets

    NASA Astrophysics Data System (ADS)

    Raufaste, C.; Bouret, Y.; Celestini, F.

    2016-05-01

    We experimentally investigate the reactivity of Leidenfrost droplets with their supporting substrates. Several organic liquids are put into contact with a copper substrate heated above their Leidenfrost temperature. As the liquid evaporates, the gaseous flow cleans the superficial copper oxide formed at the substrate surface and the reaction maintains a native copper spot below the evaporating droplet. The copper spot can reach several times the droplet size for the most reactive organic compounds. This study shows an interesting coupling between the physics of the Leidenfrost effect and the mechanics of reactive flows. Different applications are proposed such as drop motion tracking and vapor flow monitoring.

  19. Industrial Power Factor Analysis Guidebook.

    SciTech Connect

    Electrotek Concepts.

    1995-03-01

    Power factor is a way of measuring the percentage of reactive power in an electrical system. Reactive power represents wasted energy--electricity that does no useful work because the electrical current is out of phase with the voltage. Reactive power is used by inductive loads (such as, motors, transformers, fluorescent lights, arc welders and induction furnaces) to sustain their magnetic fields. Electric systems with many motors exhibit low power factors, increased conductor and transformer losses, and lower voltages. Utilities must supply both active and reactive power and compensate for these losses. Power factor can be improved by the addition of shunt capacitors. Capacitors act in opposition to inductive loads, thereby minimizing the reactive power required to serve them. In raising the power factor, shunt capacitors release energy to the system, reduce system losses, and ultimately decrease power costs. Improving system power factor can reduce reactive and active power losses for both industry and utilities through the addition of shunt capacitors. This Guide Book gives electric utility technical staff, industrial end-users, consultants and BPA employees a step-by-step method for evaluating the cost effectiveness of installing power factor correction capacitors in an industrial plant.

  20. Single-Cell E. coli Response to an Instantaneously Applied Chemotactic Signal

    PubMed Central

    Sagawa, Takashi; Kikuchi, Yu; Inoue, Yuichi; Takahashi, Hiroto; Muraoka, Takahiro; Kinbara, Kazushi; Ishijima, Akihiko; Fukuoka, Hajime

    2014-01-01

    In response to an attractant or repellant, an Escherichia coli cell controls the rotational direction of its flagellar motor by a chemotaxis system. When an E. coli cell senses an attractant, a reduction in the intracellular concentration of a chemotaxis protein, phosphorylated CheY (CheY-P), induces counterclockwise (CCW) rotation of the flagellar motor, and this cellular response is thought to occur in several hundred milliseconds. Here, to measure the signaling process occurring inside a single E. coli cell, including the recognition of an attractant by a receptor cluster, the inactivation of histidine kinase CheA, and the diffusion of CheY and CheY-P molecules, we applied a serine stimulus by instantaneous photorelease from a caged compound and examined the cellular response at a temporal resolution of several hundred microseconds. We quantified the clockwise (CW) and CCW durations immediately after the photorelease of serine as the response time and the duration of the response, respectively. The results showed that the response time depended on the distance between the receptor and motor, indicating that the decreased CheY-P concentration induced by serine propagates through the cytoplasm from the receptor-kinase cluster toward the motor with a timing that is explained by the diffusion of CheY and CheY-P molecules. The response time included 240 ms for enzymatic reactions in addition to the time required for diffusion of the signaling molecule. The measured response time and duration of the response also revealed that the E. coli cell senses a similar serine concentration regardless of whether the serine concentration is increasing or decreasing. These detailed quantitative findings increase our understanding of the signal transduction process that occurs inside cells during bacterial chemotaxis. PMID:25099812

  1. Instantaneous adhesion of Cuvierian tubules in the sea cucumber Holothuria forskali.

    PubMed

    Demeuldre, Mélanie; Chinh Ngo, Thi; Hennebert, Elise; Wattiez, Ruddy; Leclère, Philippe; Flammang, Patrick

    2014-06-01

    The peculiar Cuvierian tubules of sea cucumbers function as a defense mechanism. They thwart attacks by creating a sticky network composed of elongated tubules within which the potential predator is entangled in a matter of seconds and thus immobilized. Cuvierian tubules are typical instantaneous adhesive organs in which tissue integrity is destroyed during the release of the adhesive secretion. However, very little information is available about this adhesion process. The adhesive epithelium-the mesothelium-and the sticky material it produces were studied in the species Holothuria forskali using different microscopy techniques (light microscopy, transmission electron microscopy, scanning electron microscopy, and atomic force microscopy). The mesothelium consists of two cell types-peritoneocytes and granular cells-organized in superimposed layers. In tubules before expulsion, peritoneocytes form an outer protective cell layer preventing adhesion when not needed. After expulsion, the elongation process removes this protective layer and allows granular cells to unfold and to become exposed at the tubule surface. At this stage, Cuvierian tubules are still not sticky. Upon contact with a surface, however, granular cells release their granule contents. Once released, this material changes in aspect, swells, and spreads readily on any type of substrate where it forms a thin homogeneous layer. After tubule peeling, this layer remains on the surface but is often contaminated with collagen fibers. Atomic force microscopy demonstrated the adhesive layer to be made up of globular nanostructures measuring about 70 nm in diameter and to be more adhesive than the collagen fibers left on it. The morphological organization of Cuvierian tubules therefore allows contact-dependent deposition of an adhesive material presenting a high affinity for various surfaces. It is certainly an adaptive advantage for a defense organ to be able to entangle different types of predators.

  2. SciReader enables reading of medical content with instantaneous definitions

    PubMed Central

    2011-01-01

    Background A major problem patients encounter when reading about health related issues is document interpretation, which limits reading comprehension and therefore negatively impacts health care. Currently, searching for medical definitions from an external source is time consuming, distracting, and negatively impacts reading comprehension and memory of the material. Methods SciReader was built as a Java application with a Flex-based front-end client. The dictionary used by SciReader was built by consolidating data from several sources and generating new definitions with a standardized syntax. The application was evaluated by measuring the percentage of words defined in different documents. A survey was used to test the perceived effect of SciReader on reading time and comprehension. Results We present SciReader, a web-application that simplifies document interpretation by allowing users to instantaneously view medical, English, and scientific definitions as they read any document. This tool reveals the definitions of any selected word in a small frame at the top of the application. SciReader relies on a dictionary of ~750,000 unique Biomedical and English word definitions. Evaluation of the application shows that it maps ~98% of words in several different types of documents and that most users tested in a survey indicate that the application decreases reading time and increases comprehension. Conclusions SciReader is a web application useful for reading medical and scientific documents. The program makes jargon-laden content more accessible to patients, educators, health care professionals, and the general public. PMID:21266060

  3. An attempt to bridge muscle architecture dynamics and its instantaneous rate of force development using ultrasonography.

    PubMed

    Li, Jizhou; Zhou, Yongjin; Zheng, Yong-Ping; Li, Guanglin

    2015-08-01

    Muscle force output is an essential index in rehabilitation assessment or physical exams, and could provide considerable insights for various applications such as load monitoring and muscle assessment in sports science or rehabilitation therapy. Besides direct measurement of force output using a dynamometer, electromyography has earlier been used in several studies to quantify muscle force as an indirect means. However, its spatial resolution is easily compromised as a summation of the action potentials from neighboring motor units of electrode site. To explore an alternative method to indirectly estimate the muscle force output, and with better muscle specificity, we started with an investigation on the relationship between architecture dynamics and force output of triceps surae. The muscular architecture dynamics is captured in ultrasonography sequences and estimated using a previously reported motion estimation method. Then an indicator named as the dorsoventrally averaged motion profile (DAMP) is employed. The performance of force output is represented by an instantaneous version of the rate of force development (RFD), namely I-RFD. From experimental results on ten normal subjects, there were significant correlations between the I-RFD and DAMP for triceps surae, both normalized between 0 and 1, with the sum of squares error at 0.0516±0.0224, R-square at 0.7929±0.0931 and root mean squared error at 0.0159±0.0033. The statistical significance results were less than 0.01. The present study suggested that muscle architecture dynamics extracted from ultrasonography during contraction is well correlated to the I-RFD and it can be a promising option for indirect estimation of muscle force output.

  4. Instantaneous slip length in superhydrophobic microchannels having grooves with curved or dissimilar walls

    NASA Astrophysics Data System (ADS)

    Hemeda, A. A.; Vahedi Tafreshi, H.

    2015-10-01

    Superhydrophobic (SHP) surfaces can be used to reduce the skin-friction drag in a microchannel. This is due to the peculiar ability of these surfaces to entrap air in their pores and thereby reduce the contact area between water and the solid surface. The favorable drag-reduction effect, however, can quickly deteriorate if the surface geometry is not designed properly. The deterioration can be sudden, caused by exposure to excessive pressures, or gradual, due to the dissolution of the entrapped air into the ambient water. The formulations presented here provide a means for studying the time-dependent drag-reduction in a microchannel enhanced with transverse or longitudinal SHP grooves of varying wall profiles or wettabilities. Moreover, different mathematical approaches are developed to distinguish the performance of a sharp-edged groove from that of a groove with round entrance. The work starts by deriving an equation for the balance of forces on the air-water interface (AWI) inside a groove and solving this differential equation, along with Henry's law, for the rate of dissolution of the entrapped air into water over time. It was shown that the performance of a SHP groove depends mostly on the interplay between the effects of the apparent contact angle of the AWI and the initial volume of the groove. The instantaneous slip length is then calculated by solving the Navier-Stokes equations for flow in microchannels with SHP grooves. Our results are compared with the studies in the literature whenever available, and good agreement has been observed.

  5. Measurements of the instantaneous local heat flux in turbulent Rayleigh-Bénard convection

    NASA Astrophysics Data System (ADS)

    du Puits, Ronald; Resagk, Christian; Thess, André

    2010-07-01

    We present measurements of the instantaneous local heat flux in highly turbulent Rayleigh-Bénard (RB) convection in air (Pr=0.7) for aspect ratios in the range 1.13<=Γ<=9.00 and for Rayleigh numbers in the range 1.3×109<=Ra<=9.6×1011. The measurements have been carried out simultaneously at the surfaces of the heating and the cooling plate using a commercial sensor whose diameter is 360 times smaller than the diameter of the RB facility. We find that for all investigated values of Ra and Γ the time-averaged local heat flux at the centres of the heating and cooling plates is significantly higher than the global heat flux obtained in previous measurements. In particular, for the smallest investigated aspect ratio, Γ=1.13, the scaling exponents of the local heat fluxes as functions of the Rayleigh number are found to be considerably below those of the global heat flux obtained in experiments with cryogenic helium at Γ=1 by Niemela and Sreenivasan (2003 J. Fluid Mech. 481 355-84). Our measurements indicate that the spatial distribution of the heat flux at the heating and cooling plates is strongly nonuniform and that this nonuniformity decreases with increasing Ra and Γ. Our investigations of the time dependence of the local heat fluxes show that these quantities undergo fluctuations up to ±15% of their time-averaged values. Our work suggests that local heat flux measurements at different positions along heating and cooling plates are useful for a deeper understanding of the scaling properties of the (global) Nusselt number in RB convection.

  6. Truth and Memory: Linking Instantaneous and Retrospective Self-Reported Cigarette Consumption.

    PubMed

    Wang, Hao; Shiffman, Saul; Griffith, Sandra D; Heitjan, Daniel F

    2012-01-01

    Studies of smoking behavior commonly use the time-line follow-back (TLFB) method, or periodic retrospective recall, to gather data on daily cigarette consumption. TLFB is considered adequate for identifying periods of abstinence and lapse but not for measurement of daily cigarette consumption, thanks to substantial recall and digit preference biases. With the development of the hand-held electronic diary (ED), it has become possible to collect cigarette consumption data using ecological momentary assessment (EMA), or the instantaneous recording of each cigarette as it is smoked. EMA data, because they do not rely on retrospective recall, are thought to more accurately measure cigarette consumption. In this article we present an analysis of consumption data collected simultaneously by both methods from 236 active smokers in the pre-quit phase of a smoking cessation study. We define a statistical model that describes the genesis of the TLFB records as a two-stage process of mis-remembering and rounding, including fixed and random effects at each stage. We use Bayesian methods to estimate the model, and we evaluate its adequacy by studying histograms of imputed values of the latent remembered cigarette count. Our analysis suggests that both mis-remembering and heaping contribute substantially to the distortion of self-reported cigarette counts. Higher nicotine dependence, white ethnicity and male sex are associated with greater remembered smoking given the EMA count. The model is potentially useful in other applications where it is desirable to understand the process by which subjects remember and report true observations. PMID:24432181

  7. An instantaneous approach for determining the infrared emissivity of swine surface and the influencing factors.

    PubMed

    Zhang, Kun; Jiao, Leizi; Zhao, Xiande; Dong, Daming

    2016-04-01

    Infrared thermal imaging technology has been widely employed in temperature measurements of human and animals and its accuracy relies on the determination process of the emissivity of the target to a large extent. However, common used methods were unable to determine the emissivity of the surface of living animals and thus lower the accuracy. In this paper, we suggested a new approach to acquire the infrared emissivity of living swine in real time. In the approach, the surface temperature of swine and reference body were measured to compute the emissivity and the measurement process was completed in a non-contact and non-invasive manner. We changed the surface reflection energy of animals and reference body by changing the ambient radiant energy and obtain the surface emissivity in real time without confirming the actual temperature of animal surface. In this way, the infrared emissivity of the animal surface can be determined instantaneously and without knowing the real temperature. Both swine specimen and a living swine were used in this study. Using this method, we measured the emissivity of different body sites of the swine. The results showed that the emissivity values at different body sites show the significant differences. The emissivity values at trotter and eye were respectively 0.895 and 0.930 and the emissivity on swine surface varied from 0.945 to 0.978. More important, the distribution of the infrared emissivity on a living swine was explored and the detailed differences of the emissivity on a swine surface can be cleanly seen. Furthermore, we studied the influencing factors on the emissivity of animal surface, through measuring the emissivity distribution on swine surface when pig specimens were sprayed with water on the surface or heated using this method. This study is of great significance for the accurate measurement of swine surface temperature.

  8. Control rod reactivity measurement by rod-drop method at a fast critical assembly

    SciTech Connect

    Song, L.; Yin, Y.; Lian, X.; Zheng, C.

    2012-07-01

    Rod-drop experiments were carried out to estimate the reactivity of the control rod of a fast critical assembly operated by CAEP. Two power monitor systems were used to obtain the power level and integration method was used to process the data. Three experiments were performed. The experimental results of the reactivity from the two power monitor systems were consistent and showed a reasonable range of reactivity compared to results from positive period method. (authors)

  9. Arcjet power supply and start circuit

    NASA Technical Reports Server (NTRS)

    Gruber, Robert P. (Inventor)

    1988-01-01

    A dc power supply for spacecraft arcjet thrusters has an integral automatic starting circuit and an output averaging inductor. The output averaging inductor, in series with the load, provides instantaneous current control, and ignition pulse and an isolated signal proportional to the arc voltage. A pulse width modulated converter, close loop configured, is also incorporated to give fast response output current control.

  10. Instantaneous frequency time analysis of physiology signals: The application of pregnant women’s radial artery pulse signals

    NASA Astrophysics Data System (ADS)

    Su, Zhi-Yuan; Wang, Chuan-Chen; Wu, Tzuyin; Wang, Yeng-Tseng; Tang, Feng-Cheng

    2008-01-01

    This study used the Hilbert-Huang transform, a recently developed, instantaneous frequency-time analysis, to analyze radial artery pulse signals taken from women in their 36th week of pregnancy and after pregnancy. The acquired instantaneous frequency-time spectrum (Hilbert spectrum) is further compared with the Morlet wavelet spectrum. Results indicate that the Hilbert spectrum is especially suitable for analyzing the time series of non-stationary radial artery pulse signals since, in the Hilbert-Huang transform, signals are decomposed into different mode functions in accordance with signal’s local time scale. Therefore, the Hilbert spectrum contains more detailed information than the Morlet wavelet spectrum. From the Hilbert spectrum, we can see that radial artery pulse signals taken from women in their 36th week of pregnancy and after pregnancy have different patterns. This approach could be applied to facilitate non-invasive diagnosis of fetus’ physiological signals in the future.

  11. Point of optimal kinematic error: improvement of the instantaneous helical pivot method for locating centers of rotation.

    PubMed

    De Rosario, Helios; Page, Alvaro; Mata, Vicente

    2014-05-01

    This paper proposes a variation of the instantaneous helical pivot technique for locating centers of rotation. The point of optimal kinematic error (POKE), which minimizes the velocity at the center of rotation, may be obtained by just adding a weighting factor equal to the square of angular velocity in Woltring׳s equation of the pivot of instantaneous helical axes (PIHA). Calculations are simplified with respect to the original method, since it is not necessary to make explicit calculations of the helical axis, and the effect of accidental errors is reduced. The improved performance of this method was validated by simulations based on a functional calibration task for the gleno-humeral joint center. Noisy data caused a systematic dislocation of the calculated center of rotation towards the center of the arm marker cluster. This error in PIHA could even exceed the effect of soft tissue artifacts associated to small and medium deformations, but it was successfully reduced by the POKE estimation.

  12. Non-invasive measurement of instantaneous forces during aquatic locomotion: a case study of the bluegill sunfish pectoral fin.

    PubMed

    Peng, Jifeng; Dabiri, John O; Madden, Peter G; Lauder, George V

    2007-02-01

    Swimming and flying animals generate unsteady locomotive forces by delivering net momentum into the fluid wake. Hence, swimming and flying forces can be quantified by measuring the momentum of animal wakes. A recently developed model provides an approach to empirically deduce swimming and flying forces based on the measurement of velocity and vortex added-mass in the animal wake. The model is contingent on the identification of the vortex boundary in the wake. This paper demonstrates the application of that method to a case study quantifying the instantaneous locomotive forces generated by the pectoral fins of the bluegill sunfish (Lepomis macrochirus Rafinesque), measured using digital particle image velocimetry (DPIV). The finite-time Lyapunov exponent (FTLE) field calculated from the DPIV data was used to determine the wake vortex boundary, according to recently developed fluid dynamics theory. Momentum of the vortex wake and its added-mass were determined and the corresponding instantaneous locomotive forces were quantified at discrete time points during the fin stroke. The instantaneous forces estimated in this study agree in magnitude with the time-averaged forces quantified for the pectoral fin of the same species swimming in similar conditions and are consistent with the observed global motion of the animals. A key result of this study is its suggestion that the dynamical effect of the vortex wake on locomotion is to replace the real animal fin with an ;effective appendage', whose geometry is dictated by the FTLE field and whose interaction with the surrounding fluid is wholly dictated by inviscid concepts from potential flow theory. Benefits and limitations of this new framework for non-invasive instantaneous force measurement are discussed, and its application to comparative biomechanics and engineering studies is suggested.

  13. Non-invasive measurement of instantaneous forces during aquatic locomotion: a case study of the bluegill sunfish pectoral fin.

    PubMed

    Peng, Jifeng; Dabiri, John O; Madden, Peter G; Lauder, George V

    2007-02-01

    Swimming and flying animals generate unsteady locomotive forces by delivering net momentum into the fluid wake. Hence, swimming and flying forces can be quantified by measuring the momentum of animal wakes. A recently developed model provides an approach to empirically deduce swimming and flying forces based on the measurement of velocity and vortex added-mass in the animal wake. The model is contingent on the identification of the vortex boundary in the wake. This paper demonstrates the application of that method to a case study quantifying the instantaneous locomotive forces generated by the pectoral fins of the bluegill sunfish (Lepomis macrochirus Rafinesque), measured using digital particle image velocimetry (DPIV). The finite-time Lyapunov exponent (FTLE) field calculated from the DPIV data was used to determine the wake vortex boundary, according to recently developed fluid dynamics theory. Momentum of the vortex wake and its added-mass were determined and the corresponding instantaneous locomotive forces were quantified at discrete time points during the fin stroke. The instantaneous forces estimated in this study agree in magnitude with the time-averaged forces quantified for the pectoral fin of the same species swimming in similar conditions and are consistent with the observed global motion of the animals. A key result of this study is its suggestion that the dynamical effect of the vortex wake on locomotion is to replace the real animal fin with an ;effective appendage', whose geometry is dictated by the FTLE field and whose interaction with the surrounding fluid is wholly dictated by inviscid concepts from potential flow theory. Benefits and limitations of this new framework for non-invasive instantaneous force measurement are discussed, and its application to comparative biomechanics and engineering studies is suggested. PMID:17267654

  14. Instantaneous liquid release from a rail tanker: the influence of noise shields on pool shape and pool size.

    PubMed

    Rosmuller, Nils

    2009-05-30

    In the Netherlands, the Betuweline is a dedicated freight railway. It will, among other things, be used for transportation of all kinds of hazardous materials from the Port of Rotterdam to the German Hinterland and vice versa. The line is approximately 150 km long. Alongside the line, more than 100 km noise shields have been constructed. The question is how, and to what extent, this noise shield will affect the pool shape and size of an instantaneous release of a flammable liquid, such as liquefied petroleum gas (LPG). In case of an instantaneous release of liquid from a rail tanker (50 m(3)), both risk analysts and emergency responders use a circular pool shape of about 600 m(2) would result. To assess the influence of a noise shield, a full scale test was conducted on an already constructed part of the Betuweline. A rail tanker was filled with 50 m(3) red-colored environmentally safe liquid. The liquid was instantaneously released. A very peculiar pool shape actually results due to the presence of a noise shield. A zone between the rails and the noise shield (2m wide and 90 m long) is within 2-3 min filled with 15 cm of liquid. The total pool size area was about 750 m(2). Both shape and size deviate substantially from the traditional figures. These insights are both relevant to emergency responders for disaster abatement purposes and to risk analysts for effective modeling purposes. The Dutch Ministry of Transport is examining possible strategies to deal with these results. The results of this study are based upon one single instantaneous release test. In addition, it is valuable to find out what the pool shape and size would be in case of a continuous release from the rail tanker near a noise shield.

  15. An inventory model with linear holding cost and stock-dependent demand for non-instantaneous deteriorating items

    NASA Astrophysics Data System (ADS)

    Kumar, Satish; Malik, A. K.; Sharma, Abhishek; Yadav, S. K.; Singh, Yashveer

    2016-03-01

    The importance of inventory models with non-instantaneously deteriorating items in the management system has been discussed. The holding cost is taken as in linear function of time and demand is stock dependent. For this inventory model, we obtained the optimal order quantity and the total present value of profits. Further, optimality and sensitivity analysis of the optimal profit of the inventory model with key constraints is followed with the help of numerical example.

  16. Shallow layer simulation of heavy gas released on a slope in a calm ambient. Part II. Instantaneous releases.

    PubMed

    Hankin, Robin K S

    2003-10-31

    This paper assesses the value of shallow layer modelling for instantaneous releases of heavy gas over a slope using the established computer model TWODEE [R.K.S. Hankin, Heavy gas dispersion over complex terrain, Ph.D. thesis, Cambridge University, 1997; J. Hazard. Mater. 66 (1999) 211; J. Hazard. Mater. 66 (1999) 227; J. Hazard. Mater. 66 (1999) 239] and the experimental results of Schatzmann et al. [M. Schatzmann, K. Marotzke, J. Donat, Research on continuous and instantaneous heavy gas clouds, Contribution of sub-project EV 4T-0021-D to the final report of the joint CEC project, Technical report, Meteorological Institute, University of Hamburg, February 1991]. This is the second of a two-part paper; part I considered continuous releases using the same model, using the same entrainment parameters. Schatzmann et al. carried out instantaneous releases of heavy gas over three slopes; each experiment was repeated five times under nominally identical conditions. The goodness-of-fit measures (GFMs) of Hanna et al. [Atmos. Environ. 27A (15) (1993) 2265] are generalized to account for the multiple releases carried out by Schatzmann et al. Using these statistical GFMs, predicted peak concentrations are generally correct to within a factor of two; and cloud arrival times are generally late.

  17. Characterization of gear faults in variable rotating speed using Hilbert-Huang Transform and instantaneous dimensionless frequency normalization

    NASA Astrophysics Data System (ADS)

    Wu, T. Y.; Chen, J. C.; Wang, C. C.

    2012-07-01

    The objective of this research is to investigate the feasibility of utilizing the instantaneous dimensionless frequency (DLF) normalization and Hilbert-Huang Transform (HHT) to characterize the different gear faults in case of variable rotating speed. The normalized DLF of the vibration signals are calculated based on the rotating speed of shaft and the instantaneous frequencies of Intrinsic Mode Functions (IMFs) which are decomposed by Empirical Mode Decomposition (EMD) process. The faulty gear features on DLF-energy distribution of vibration signal can be extracted without the presence of shaft rotating speed, so that the proposed approach can be applied for characterizing the malfunctions of gearbox system under variable shaft rotating speed. A test rig of gear transmission system is performed to illustrate the gear faults, including worn tooth, broken tooth and gear unbalance. Different methods to determine the instantaneous frequency are employed to verify the consistence of characterization results. The DLF-energy distributions of vibration signals are investigated in different faulty gear conditions. The analysis results demonstrate the capability and effectiveness of the proposed approach for characterizing the gear malfunctions at the DLFs corresponding to the meshing frequency as well as the shaft rotating frequency. The support vector machine (SVM) is then employed to classify the vibration patterns of gear transmission system at different malfunctions. Using the energy distribution at the characteristic DLFs as the features, the different fault types of gear can be identified by SVM with high accuracy.

  18. Spectral methods for compressible reactive flows

    NASA Astrophysics Data System (ADS)

    Gottlieb, David; Gottlieb, Sigal

    2005-01-01

    High order simulations are necessary in order to capture fine details in resolving supersonic reactive flows. However, high Mach number compressible flows feature sharp gradients and discontinuities, which present a challenge to successful simulations using high order methods. Spectral methods have proven a powerful tool in simulation of incompressible turbulent flows, and recent advances allow the application of spectral methods to compressible reactive flows. We review the recent advances in the theory and application of spectral methods which allow stable computations of discontinuous phenomena, and the recovery of high order information via postprocessing, and present applications of high Mach number reactive flows. To cite this article: D. Gottlieb, S. Gottlieb, C. R. Mecanique 333 (2005).

  19. Effect of grip strength and grip strengthening exercises on instantaneous bat velocity of collegiate baseball players.

    PubMed

    Hughes, Shawn S; Lyons, Brian C; Mayo, Jerry J

    2004-05-01

    Bat velocity is considered to be an important factor for successful hitting. The relationship between grip strength and bat velocity has not been conclusively established. The purposes of this study were to determine the relationship of grip strength to bat velocity and to ascertain whether the performance of resistance training exercises designed to specifically target the forearms and grip would significantly alter bat velocity. The subjects for this study were 23 male members (mean +/- SD, age = 19.7 +/- 1.3 years, height = 182.5 +/- 5.9 cm, weight = 85.4 +/- 15.5 kg, experience = 14.4 +/- 1.7 years) of a varsity baseball team at a National Collegiate Athletic Association Division II school. The Jamar hand dynamometer was used to test grip strength, and the SETPRO Rookie was used to measure instantaneous bat velocity at the point of contact with the ball. Subjects were randomly divided into an experimental group and a control group. For 6 weeks, both groups participated in their usual baseball practice sessions, but the experimental group also performed extra forearm and grip strengthening exercises, whereas the control group did not. Pretest and posttest correlations between grip strength and bat velocity revealed no significant relationship between grip strength and bat velocity (pretest r = 0.054, p = 0.807; posttest r = 0.315, p = 0.145). A dependent t-test performed on all subjects revealed that a significant (p = 0.001) increase in bat velocity did occur over the course of the study. A covariate analysis, employing pretest bat velocity as the covariate, revealed no significant difference (p = 0.795) in posttest bat velocity scores between the experimental and control groups. Thus, increases in bat velocity occurred, but the differences were similar for both the experimental and control groups. The findings of this study suggest that grip strength and bat velocity are not significantly related, and that the allocation of time and energy for added training

  20. Describing and compensating gas transport dynamics for accurate instantaneous emission measurement

    NASA Astrophysics Data System (ADS)

    Weilenmann, Martin; Soltic, Patrik; Ajtay, Delia

    Instantaneous emission measurements on chassis dynamometers and engine test benches are becoming increasingly usual for car-makers and for environmental emission factor measurement and calculation, since much more information about the formation conditions can be extracted than from the regulated bag measurements (integral values). The common exhaust gas analysers for the "regulated pollutants" (carbon monoxide, total hydrocarbons, nitrogen oxide, carbon dioxide) allow measurement at a rate of one to ten samples per second. This gives the impression of having after-the-catalyst emission information with that chronological precision. It has been shown in recent years, however, that beside the reaction time of the analysers, the dynamics of gas transport in both the exhaust system of the car and the measurement system last significantly longer than 1 s. This paper focuses on the compensation of all these dynamics convoluting the emission signals. Most analysers show linear and time-invariant reaction dynamics. Transport dynamics can basically be split into two phenomena: a pure time delay accounting for the transport of the gas downstream and a dynamic signal deformation since the gas is mixed by turbulence along the way. This causes emission peaks to occur which are smaller in height and longer in time at the sensors than they are after the catalyst. These dynamics can be modelled using differential equations. Both mixing dynamics and time delay are constant for modelling a raw gas analyser system, since the flow in that system is constant. In the exhaust system of the car, however, the parameters depend on the exhaust volume flow. For gasoline cars, the variation in overall transport time may be more than 6 s. It is shown in this paper how all these processes can be described by invertible mathematical models with the focus on the more complex case of the car's exhaust system. Inversion means that the sharp emission signal at the catalyst out location can be

  1. Estimation of instantaneous peak flow from daily data using the HBV model

    NASA Astrophysics Data System (ADS)

    Ding, Jie; Haberlandt, Uwe

    2015-04-01

    The length of the observed instantaneous peak flow (IPF) period has a great influence on the flood design whereas these high resolution flow data are not always available. Our previous research has shown that IPFs can be derived from the easier available observed long time series of mean daily flows (MDFs) using a multiple regression model. The primary aim here is to explore the possibility of deriving frequency distributions of IPFs using hydrological modelling with daily and hourly time steps in comparison. In the post-correction approach the rainfall-runoff model is operated on daily time steps , a flood frequency distribution is fitted to the simulated annual MDFs and the resulting daily quantiles are transferred into IPF quantiles using the multiple regression model. In the pre-processing approach, hourly rainfall is produced by disaggregation of daily data. Then the rainfall-runoff model is operated on hourly time steps resulting in a frequency distribution of IPFs. In addition, two calibrations strategies for the hydrological model using the hydrograph and using flow statistics, respectively, are applied for both approaches. Finally, the performances of estimating the IPFs from daily data using these two approaches are compared considering also the two different calibration strategies. The hydrological simulations are carried out with the HBV-IWW model and the case study is carried out for 18 catchments of the Aller-Leine-River basin in northern Germany. The results show that: (1) the multiple regression model is capable to predict IPFs with the simulated MDFs as well; (2) the estimation of extreme flow quantiles in summer is not as good as in winter; (3) both of the two approaches enable a reasonable estimation of IPFs; (4) if on hand the hydrological model is calibrated on the hydrograph the post-correction approach with daily simulations is superior and if on the other hand the model is calibrated on flow statistics the pre-processing with hourly

  2. Mechanical deformation model of the western United States instantaneous strain-rate field

    USGS Publications Warehouse

    Pollitz, F.F.; Vergnolle, M.

    2006-01-01

    We present a relationship between the long-term fault slip rates and instantaneous velocities as measured by Global Positioning System (GPS) or other geodetic measurements over a short time span. The main elements are the secularly increasing forces imposed by the bounding Pacific and Juan de Fuca (JdF) plates on the North American plate, viscoelastic relaxation following selected large earthquakes occurring on faults that are locked during their respective interseismic periods, and steady slip along creeping portions of faults in the context of a thin-plate system. In detail, the physical model allows separate treatments of faults with known geometry and slip history, faults with incomplete characterization (i.e. fault geometry but not necessarily slip history is available), creeping faults, and dislocation sources distributed between the faults. We model the western United States strain-rate field, derived from 746 GPS velocity vectors, in order to test the importance of the relaxation from historic events and characterize the tectonic forces imposed by the bounding Pacific and JdF plates. Relaxation following major earthquakes (M ??? 8.0) strongly shapes the present strain-rate field over most of the plate boundary zone. Equally important are lateral shear transmitted across the Pacific-North America plate boundary along ???1000 km of the continental shelf, downdip forces distributed along the Cascadia subduction interface, and distributed slip in the lower lithosphere. Post-earthquake relaxation and tectonic forcing, combined with distributed deep slip, constructively interfere near the western margin of the plate boundary zone, producing locally large strain accumulation along the San Andreas fault (SAF) system. However, they destructively interfere further into the plate interior, resulting in smaller and more variable strain accumulation patterns in the eastern part of the plate boundary zone. Much of the right-lateral strain accumulation along the SAF

  3. Statistical Analysis of Instantaneous Frequency Scaling Factor as Derived From Optical Disdrometer Measurements At KQ Bands

    NASA Technical Reports Server (NTRS)

    Zemba, Michael; Nessel, James; Houts, Jacquelynne; Luini, Lorenzo; Riva, Carlo

    2016-01-01

    The rain rate data and statistics of a location are often used in conjunction with models to predict rain attenuation. However, the true attenuation is a function not only of rain rate, but also of the drop size distribution (DSD). Generally, models utilize an average drop size distribution (Laws and Parsons or Marshall and Palmer. However, individual rain events may deviate from these models significantly if their DSD is not well approximated by the average. Therefore, characterizing the relationship between the DSD and attenuation is valuable in improving modeled predictions of rain attenuation statistics. The DSD may also be used to derive the instantaneous frequency scaling factor and thus validate frequency scaling models. Since June of 2014, NASA Glenn Research Center (GRC) and the Politecnico di Milano (POLIMI) have jointly conducted a propagation study in Milan, Italy utilizing the 20 and 40 GHz beacon signals of the Alphasat TDP#5 Aldo Paraboni payload. The Ka- and Q-band beacon receivers provide a direct measurement of the signal attenuation while concurrent weather instrumentation provides measurements of the atmospheric conditions at the receiver. Among these instruments is a Thies Clima Laser Precipitation Monitor (optical disdrometer) which yields droplet size distributions (DSD); this DSD information can be used to derive a scaling factor that scales the measured 20 GHz data to expected 40 GHz attenuation. Given the capability to both predict and directly observe 40 GHz attenuation, this site is uniquely situated to assess and characterize such predictions. Previous work using this data has examined the relationship between the measured drop-size distribution and the measured attenuation of the link]. The focus of this paper now turns to a deeper analysis of the scaling factor, including the prediction error as a function of attenuation level, correlation between the scaling factor and the rain rate, and the temporal variability of the drop size

  4. Statistical Analysis of Instantaneous Frequency Scaling Factor as Derived From Optical Disdrometer Measurements At KQ Bands

    NASA Technical Reports Server (NTRS)

    Zemba, Michael; Nessel, James; Houts, Jacquelynne; Luini, Lorenzo; Riva, Carlo

    2016-01-01

    The rain rate data and statistics of a location are often used in conjunction with models to predict rain attenuation. However, the true attenuation is a function not only of rain rate, but also of the drop size distribution (DSD). Generally, models utilize an average drop size distribution (Laws and Parsons or Marshall and Palmer [1]). However, individual rain events may deviate from these models significantly if their DSD is not well approximated by the average. Therefore, characterizing the relationship between the DSD and attenuation is valuable in improving modeled predictions of rain attenuation statistics. The DSD may also be used to derive the instantaneous frequency scaling factor and thus validate frequency scaling models. Since June of 2014, NASA Glenn Research Center (GRC) and the Politecnico di Milano (POLIMI) have jointly conducted a propagation study in Milan, Italy utilizing the 20 and 40 GHz beacon signals of the Alphasat TDP#5 Aldo Paraboni payload. The Ka- and Q-band beacon receivers provide a direct measurement of the signal attenuation while concurrent weather instrumentation provides measurements of the atmospheric conditions at the receiver. Among these instruments is a Thies Clima Laser Precipitation Monitor (optical disdrometer) which yields droplet size distributions (DSD); this DSD information can be used to derive a scaling factor that scales the measured 20 GHz data to expected 40 GHz attenuation. Given the capability to both predict and directly observe 40 GHz attenuation, this site is uniquely situated to assess and characterize such predictions. Previous work using this data has examined the relationship between the measured drop-size distribution and the measured attenuation of the link [2]. The focus of this paper now turns to a deeper analysis of the scaling factor, including the prediction error as a function of attenuation level, correlation between the scaling factor and the rain rate, and the temporal variability of the drop

  5. Mapping Land and Water Surface Topography with instantaneous Structure from Motion

    NASA Astrophysics Data System (ADS)

    Dietrich, J.; Fonstad, M. A.

    2012-12-01

    Structure from Motion (SfM) has given researchers an invaluable tool for low-cost, high-resolution 3D mapping of the environment. These SfM 3D surface models are commonly constructed from many digital photographs collected with one digital camera (either handheld or attached to aerial platform). This method works for stationary or very slow moving objects. However, objects in motion are impossible to capture with one-camera SfM. With multiple simultaneously triggered cameras, it becomes possible to capture multiple photographs at the same time which allows for the construction 3D surface models of moving objects and surfaces, an instantaneous SfM (ISfM) surface model. In river science, ISfM provides a low-cost solution for measuring a number of river variables that researchers normally estimate or are unable to collect over large areas. With ISfM and sufficient coverage of the banks and RTK-GPS control it is possible to create a digital surface model of land and water surface elevations across an entire channel and water surface slopes at any point within the surface model. By setting the cameras to collect time-lapse photography of a scene it is possible to create multiple surfaces that can be compared using traditional digital surface model differencing. These water surface models could be combined the high-resolution bathymetry to create fully 3D cross sections that could be useful in hydrologic modeling. Multiple temporal image sets could also be used in 2D or 3D particle image velocimetry to create 3D surface velocity maps of a channel. Other applications in earth science include anything where researchers could benefit from temporal surface modeling like mass movements, lava flows, dam removal monitoring. The camera system that was used for this research consisted of ten pocket digital cameras (Canon A3300) equipped with wireless triggers. The triggers were constructed with an Arduino-style microcontroller and off-the-shelf handheld radios with a maximum

  6. Instantaneous longwave radiative impact of ozone: an application on IASI/MetOp observations

    NASA Astrophysics Data System (ADS)

    Doniki, S.; Hurtmans, D.; Clarisse, L.; Clerbaux, C.; Worden, H. M.; Bowman, K. W.; Coheur, P.-F.

    2015-08-01

    Ozone is an important greenhouse gas in terms of anthropogenic radiative forcing (RF). RF calculations for ozone were until recently entirely model based and significant discrepancies were reported due to different model characteristics. However, new instantaneous radiative kernels (IRKs) calculated from hyperspectral thermal IR satellites have been able to help adjudicate between different climate model RF calculations. IRKs are defined as the sensitivity of the outgoing longwave radiation (OLR) flux with respect to the ozone vertical distribution in the full 9.6 μm band. Previous methods applied to measurements from the Tropospheric Emission Spectrometer (TES) on Aura, rely on an anisotropy approximation for the angular integration. In this paper, we present a more accurate but more computationally expensive method to calculate these kernels. The method of direct integration is based on similar principles with the anisotropy approximation, but deals more precisely with the integration of the Jacobians. We describe both methods and highlight their differences with respect to the IRKs and the ozone longwave radiative effect (LWRE), i.e. the radiative impact in OLR due to absorption by ozone, for both tropospheric and total columns, from measurements of the Infrared Atmospheric Sounding Interferometer (IASI) onboard MetOp-A. Biases between the two methods vary from -25 to +20 % for the LWRE, depending on the viewing angle. These biases point to the inadequacy of the anisotropy method, especially at nadir, suggesting that the TES derived LWRE are biased low by around 25 % and that chemistry-climate model OLR biases with respect to TES are underestimated. In this paper we also exploit the sampling performance of IASI to obtain first daily global distributions of the LWRE, for 12 days (the 15th of each month) in 2011, calculated with the direct integration method. We show that the temporal variation of global and latitudinal averages of the LWRE shows patterns which

  7. Instantaneous longwave radiative impact of ozone: an application on IASI/MetOp observations

    NASA Astrophysics Data System (ADS)

    Doniki, S.; Hurtmans, D.; Clarisse, L.; Clerbaux, C.; Worden, H. M.; Bowman, K. W.; Coheur, P.-F.

    2015-11-01

    Ozone is an important greenhouse gas in terms of anthropogenic radiative forcing (RF). RF calculations for ozone were until recently entirely model based, and significant discrepancies were reported due to different model characteristics. However, new instantaneous radiative kernels (IRKs) calculated from hyperspectral thermal IR satellites have been able to help adjudicate between different climate model RF calculations. IRKs are defined as the sensitivity of the outgoing longwave radiation (OLR) flux with respect to the ozone vertical distribution in the full 9.6 μm band. Previous methods applied to measurements from the Tropospheric Emission Spectrometer (TES) on Aura rely on an anisotropy approximation for the angular integration. In this paper, we present a more accurate but more computationally expensive method to calculate these kernels. The method of direct integration is based on similar principles to the anisotropy approximation, but it deals more precisely with the integration of the Jacobians. We describe both methods and highlight their differences with respect to the IRKs and the ozone longwave radiative effect (LWRE), i.e., the radiative impact in OLR due to absorption by ozone, for both tropospheric and total columns, from measurements of the Infrared Atmospheric Sounding Interferometer (IASI) onboard MetOp-A. Biases between the two methods vary from -25 to +20 % for the LWRE, depending on the viewing angle. These biases point to the inadequacy of the anisotropy method, especially at nadir, suggesting that the TES-derived LWREs are biased low by around 25 % and that chemistry-climate model OLR biases with respect to TES are underestimated. In this paper we also exploit the sampling performance of IASI to obtain first daily global distributions of the LWRE, for 12 days (the 15th of each month) in 2011, calculated with the direct integration method. We show that the temporal variation of global and latitudinal averages of the LWRE shows patterns

  8. Simultaneous and instantaneous measurement of velocity and density in Rayleigh-Taylor mixing layers

    NASA Astrophysics Data System (ADS)

    Kraft, Wayne Neal

    There are two coupled primary objectives for this study of buoyancy-driven turbulence. The first objective is to create a new diagnostic for collection of measurements to capture the physics of Rayleigh-Taylor (RT) mixing. The second objective is to use the new diagnostic to specifically elucidate the physics of large Atwood number, At = (rho1 - rho 2)/(rho1+ rho2), RT mixing. Both of these objectives have been satisfied through the development of a new hot-wire diagnostic to study buoyancy-driven turbulence in a statistically steady gas channel of helium and air (0.03 ≤ At ≤ 0.6). The capability of the diagnostic to simultaneously and instantaneously measure turbulent velocity and density fluctuations allows for a unique investigation into the dynamics of Rayleigh-Taylor mixing layers at large A t, through measurements of turbulence and mixing statistics. The new hot-wire diagnostic uses temperature as a fluid marker for helium and air, which is possible due to the Lewis number ˜ 1 (Le = ratio of thermal diffusivity to mass diffusivity) for helium and air, and the new diagnostic has been validated in an At = 0.03 mixing layer. The energy density spectrum of rho'v', measured experimentally for the first time in RT mixing, is found to closely follow the energy distribution of v', up to the Reynolds numbers investigated (Reh = (2h)3/2 gAt/6 /vmix ˜ 1450). Large A t experiments, with At = 0.6, have also been achieved for the first time in a miscible RT mixing layer. An asymmetric penetration of the bubbles (rising fluid) and spikes (falling fluid) has been observed, resulting in measured self similar growth parameters alpha b = 0.060 and alphas = 0.088 for the bubbles and spikes, respectively. The first experimental measurements of turbulent velocity and density fluctuations for the large At case, show a strong similarity to lower At behaviors when normalized. However conditional statistics, which separate the bubble (light fluid) and spike (heavy fluid

  9. Effect of grip strength and grip strengthening exercises on instantaneous bat velocity of collegiate baseball players.

    PubMed

    Hughes, Shawn S; Lyons, Brian C; Mayo, Jerry J

    2004-05-01

    Bat velocity is considered to be an important factor for successful hitting. The relationship between grip strength and bat velocity has not been conclusively established. The purposes of this study were to determine the relationship of grip strength to bat velocity and to ascertain whether the performance of resistance training exercises designed to specifically target the forearms and grip would significantly alter bat velocity. The subjects for this study were 23 male members (mean +/- SD, age = 19.7 +/- 1.3 years, height = 182.5 +/- 5.9 cm, weight = 85.4 +/- 15.5 kg, experience = 14.4 +/- 1.7 years) of a varsity baseball team at a National Collegiate Athletic Association Division II school. The Jamar hand dynamometer was used to test grip strength, and the SETPRO Rookie was used to measure instantaneous bat velocity at the point of contact with the ball. Subjects were randomly divided into an experimental group and a control group. For 6 weeks, both groups participated in their usual baseball practice sessions, but the experimental group also performed extra forearm and grip strengthening exercises, whereas the control group did not. Pretest and posttest correlations between grip strength and bat velocity revealed no significant relationship between grip strength and bat velocity (pretest r = 0.054, p = 0.807; posttest r = 0.315, p = 0.145). A dependent t-test performed on all subjects revealed that a significant (p = 0.001) increase in bat velocity did occur over the course of the study. A covariate analysis, employing pretest bat velocity as the covariate, revealed no significant difference (p = 0.795) in posttest bat velocity scores between the experimental and control groups. Thus, increases in bat velocity occurred, but the differences were similar for both the experimental and control groups. The findings of this study suggest that grip strength and bat velocity are not significantly related, and that the allocation of time and energy for added training

  10. Comonitoring of adenosine and dopamine using the Wireless Instantaneous Neurotransmitter Concentration System: proof of principle

    PubMed Central

    Shon, Young-Min; Chang, Su-Youne; Tye, Susannah J.; Kimble, Christopher J.; Bennet, Kevin E.; Blaha, Charles D.; Lee, Kendall H.

    2010-01-01

    Object The authors of previous studies have demonstrated that local adenosine efflux may contribute to the therapeutic mechanism of action of thalamic deep brain stimulation (DBS) for essential tremor. Real-time monitoring of the neurochemical output of DBS-targeted regions may thus advance functional neurosurgical procedures by identifying candidate neurotransmitters and neuromodulators involved in the physiological effects of DBS. This would in turn permit the development of a method of chemically guided placement of DBS electrodes in vivo. Designed in compliance with FDA-recognized standards for medical electrical device safety, the authors report on the utility of the Wireless Instantaneous Neurotransmitter Concentration System (WINCS) for real-time comonitoring of electrical stimulation–evoked adenosine and dopamine efflux in vivo, utilizing fast-scan cyclic voltammetry (FSCV) at a polyacrylonitrile-based (T-650) carbon fiber microelectrode (CFM). Methods The WINCS was used for FSCV, which consisted of a triangle wave scanned between −0.4 and +1.5 V at a rate of 400 V/second and applied at 10 Hz. All voltages applied to the CFM were with respect to an Ag/AgCl reference electrode. The CFM was constructed by aspirating a single T-650 carbon fiber (r = 2.5 μm) into a glass capillary and pulling to a microscopic tip using a pipette puller. The exposed carbon fiber (the sensing region) extended beyond the glass insulation by ∼ 50 μm. Proof of principle tests included in vitro measurements of adenosine and dopamine, as well as in vivo measurements in urethane-anesthetized rats by monitoring adenosine and dopamine efflux in the dorsomedial caudate putamen evoked by high-frequency electrical stimulation of the ventral tegmental area and substantia nigra. Results The WINCS provided reliable, high-fidelity measurements of adenosine efflux. Peak oxidative currents appeared at +1.5 V and at +1.0 V for adenosine, separate from the peak oxidative current at +0.6 V

  11. [Biodegradation of reactive turquoise blue].

    PubMed

    Fu, L; Wen, X; Xu, L; Qian, Y

    2001-07-01

    In this study, the anaerobic degradation and the aerobic degradation of a kind of reactive dye--Reactive Turquoise Blue(RTB) were compared. The results proved that anaerobic sludge could only decompose RTB in the presence of glucose while aerobic sludge decomposed RTB with or without the presence of glucose (RTB of 20 mg/L was reduced by 37.4% through 24 hours' aerobic treatment with RTB as sole carbon source). The enhancement of glucose concentration was beneficial for both anaerobic and aerobic degradation of RTB: the anaerobic and the aerobic removal efficiencies were respectively 81.5% and 73.6% with RTB of 20 mg/L and glucose of 1200 mg/L. In the influent RTB concentration also had influence on the activity of anaerobic and aerobic microorganisms. When glucose concentration was 800 mg/L or 1200 mg/L and RTB concentration was 20 mg/L to 100 mg/L, anaerobic removal efficiency of RTB was higher than aerobic removal efficiency by 4.9%-27.2%, which meant that anaerobic bacteria is more powerful than aerobic bacteria in terms of RTB removal.

  12. Phenylethynyl terminated reactive oligomer

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G. (Inventor); Jensen, Brian J. (Inventor); Hergenrother, Paul M. (Inventor)

    1995-01-01

    A composition of matter having the general structure: ##STR1## (wherein X is F, Cl, or NO.sub.2, and Y is CO, SO.sub.2 or C(CF.sub.3).sub.2) is employed to terminate a nucleophilic reagent, resulting in the exclusive production of phenylethynyl terminated reactive oligomers which display unique thermal characteristics. A reactive diluent having the general structure: ##STR2## (wherein R is any aliphatic or aromatic moiety) is employed to decrease the melt viscosity of a phenylethynyl terminated reactive oligomer and to subsequently react therewith to provide a thermosetting material of enhanced density. These materials have features which make them attractive candidates for use as composite matrices and adhesives.

  13. Modeling Atmospheric Reactive Nitrogen

    EPA Science Inventory

    Nitrogen is an essential building block of all proteins and thus an essential nutrient for all life. Reactive nitrogen, which is naturally produced via enzymatic reactions, forest fires and lightning, is continually recycled and cascades through air, water, and soil media. Human ...

  14. Wavelet assessment of cerebrospinal compensatory reserve and cerebrovascular pressure reactivity

    NASA Astrophysics Data System (ADS)

    Latka, M.; Turalska, M.; Kolodziej, W.; Latka, D.; West, B.

    2006-03-01

    We employ complex continuous wavelet transforms to develop a consistent mathematical framework capable of quantifying both cerebrospinal compensatory reserve and cerebrovascular pressure--reactivity. The wavelet gain, defined as the frequency dependent ratio of time averaged wavelet coefficients of intracranial (ICP) and arterial blood pressure (ABP) fluctuations, characterizes the dampening of spontaneous arterial blood oscillations. This gain is introduced as a novel measure of cerebrospinal compensatory reserve. For a group of 10 patients who died as a result of head trauma (Glasgow Outcome Scale GOS =1) the average gain is 0.45 calculated at 0.05 Hz significantly exceeds that of 16 patients with favorable outcome (GOS=2): with gain of 0.24 with p=4x10-5. We also study the dynamics of instantaneous phase difference between the fluctuations of the ABP and ICP time series. The time-averaged synchronization index, which depends upon frequency, yields the information about the stability of the phase difference and is used as a cerebrovascular pressure--reactivity index. The average phase difference for GOS=1 is close to zero in sharp contrast to the mean value of 30^o for patients with GOS=2. We hypothesize that in patients who died the impairment of cerebral autoregulation is followed by the break down of residual pressure reactivity.

  15. Remote assessment of instantaneous changes in water chemistry after liming in a Nova Scotia catchment

    NASA Astrophysics Data System (ADS)

    Angelidis, Christine

    2013-04-01

    Remote assessment of instantaneous changes in water chemistry after liming in a Nova Scotia catchment ANGELIDIS, C.1, STERLING, S.1, BREEN, A.2, BIAGI, K.1., and CLAIR, T.A.1 1Dalhousie University, christine.angelidis@dal.ca, 2Bluenose Coastal Action Foundation, andrew@coastalaction.org Southwestern Nova Scotia has some of the most acidic freshwaters in North America due to its location downwind of the major emission sources in eastern Canada and the US and due to a resistant geology which offers little acid buffering capacity (Clair et al. 2007). Because of the poor buffering and regionally high runoff values, hydrological events such as snowmelt and rain storms are frequent and can cause sudden changes in water chemistry which can have devastating effects on freshwater biota due to increases in acidity and metals (Dennis and Clair in press). Clair et al. (2001) have estimated the potential frequency of acidic episodes in this region based on a number of hydrological factors, though the technology available at the time to monitor short-term changes was not dependable. Recent advances in equipment have made the assessment of the frequency and severity of acidic episodes easier and more accurate, allowing better interpretation and prediction of hydrogeochemical changes with variations in weather and deposition patterns. Here we take advantage of these recent advances to monitor water chemistry in an experimental catchment, and explore the response to catchment liming. Catchment liming is one way of mitigating the effects of acid deposition in sensitive areas. We limed a 50 ha catchment at a rate of 5 t/ha in the Gold River watershed of southwest Nova Scotia to examine the interactions between application of lime with the geological and climatological conditions of this region and acid episode frequency. In order to assess changes of episode frequency caused by liming, we established two mobile environmental monitoring platforms in the catchment: a control site

  16. Statistical redundancy of instantaneous phases: theory and application to the seismic ambient wavefield

    NASA Astrophysics Data System (ADS)

    Gaudot, Ianis; Beucler, Éric; Mocquet, Antoine; Schimmel, Martin; Le Feuvre, Mathieu

    2016-04-01

    In order to detect possible signal redundancies in the seismic ambient wavefield, we develop a new method based on pairwise comparisons among a set of synchronous time-series. This approach is based on instantaneous phase coherence statistics. The first and second moments of the pairwise phase coherence distribution are used to characterize the phase randomness. Both theory and synthetic experiments show that, for perfect phase randomness, the theoretical values of the mean and variance are equal to 0 and 1 ‑ 2/π, respectively. As a consequence, any deviation from these values indicates the presence of a redundant phase in the raw continuous signal. Using the ergodicity property of a random signal, we split an initial time-series into a set of synchronous signals. This allows us to detect and to quantify the repetitiveness of any possible temporally persistent and spatially localized source, during a given period of observation. In the case of the detection of a redundant phase, individual coherences (one trace against all others) quantify the contribution of each time-series independently. A previously detected 26 s period microseismic source located near the Gulf of Guinea is used to illustrate one of the possible ways of handling phase coherence statistics. We use the continuous vertical component data recorded during the month of 2004 August by four broad-band stations of the Federation of Digital Seismography Network. To compute coherence statistics among a set composed of a sufficient number of synchronous traces, the raw seismic signal is split into 372 2-hr sliding time windows. Only the basic signal processing steps (including removing the mean, trend and the instrumental response) are applied. After bandpass filtering the data between 23 and 32 s periods, the 2-hr time-series are cross-correlated, leading to a set of 372 synchronous cross-correlations for each station pair. We observe that, for all station pairs, the mean overall coherence value is

  17. Applications of the Conceptual Density Functional Theory Indices to Organic Chemistry Reactivity.

    PubMed

    Domingo, Luis R; Ríos-Gutiérrez, Mar; Pérez, Patricia

    2016-01-01

    Theoretical reactivity indices based on the conceptual Density Functional Theory (DFT) have become a powerful tool for the semiquantitative study of organic reactivity. A large number of reactivity indices have been proposed in the literature. Herein, global quantities like the electronic chemical potential μ, the electrophilicity ω and the nucleophilicity N indices, and local condensed indices like the electrophilic P k + and nucleophilic P k - Parr functions, as the most relevant indices for the study of organic reactivity, are discussed. PMID:27294896

  18. Applications of the Conceptual Density Functional Theory Indices to Organic Chemistry Reactivity.

    PubMed

    Domingo, Luis R; Ríos-Gutiérrez, Mar; Pérez, Patricia

    2016-06-09

    Theoretical reactivity indices based on the conceptual Density Functional Theory (DFT) have become a powerful tool for the semiquantitative study of organic reactivity. A large number of reactivity indices have been proposed in the literature. Herein, global quantities like the electronic chemical potential μ, the electrophilicity ω and the nucleophilicity N indices, and local condensed indices like the electrophilic P k + and nucleophilic P k - Parr functions, as the most relevant indices for the study of organic reactivity, are discussed.

  19. Measuring Memory Reactivation With Functional MRI: Implications for Psychological Theory.

    PubMed

    Levy, Benjamin J; Wagner, Anthony D

    2013-01-01

    Environmental cues often remind us of earlier experiences by triggering the reactivation of memories of events past. Recent evidence suggests that memory reactivation can be observed using functional MRI and that distributed pattern analyses can even provide evidence of reactivation on individual trials. The ability to measure memory reactivation offers unique and powerful leverage on theoretical issues of long-standing interest in cognitive psychology, providing a means to address questions that have proven difficult to answer with behavioral data alone. In this article, we consider three instances. First, reactivation measures can indicate whether memory-based inferences (i.e., generalization) arise through the encoding of integrated cross-event representations or through the flexible expression of separable event memories. Second, online measures of memory reactivation may inform theories of forgetting by providing information about when competing memories are reactivated during competitive retrieval situations. Finally, neural reactivation may provide a window onto the role of replay in memory consolidation. The ability to track memory reactivation, including at the individual trial level, provides unique leverage that is not afforded by behavioral measures and thus promises to shed light on such varied topics as generalization, integration, forgetting, and consolidation.

  20. Measuring Memory Reactivation With Functional MRI: Implications for Psychological Theory.

    PubMed

    Levy, Benjamin J; Wagner, Anthony D

    2013-01-01

    Environmental cues often remind us of earlier experiences by triggering the reactivation of memories of events past. Recent evidence suggests that memory reactivation can be observed using functional MRI and that distributed pattern analyses can even provide evidence of reactivation on individual trials. The ability to measure memory reactivation offers unique and powerful leverage on theoretical issues of long-standing interest in cognitive psychology, providing a means to address questions that have proven difficult to answer with behavioral data alone. In this article, we consider three instances. First, reactivation measures can indicate whether memory-based inferences (i.e., generalization) arise through the encoding of integrated cross-event representations or through the flexible expression of separable event memories. Second, online measures of memory reactivation may inform theories of forgetting by providing information about when competing memories are reactivated during competitive retrieval situations. Finally, neural reactivation may provide a window onto the role of replay in memory consolidation. The ability to track memory reactivation, including at the individual trial level, provides unique leverage that is not afforded by behavioral measures and thus promises to shed light on such varied topics as generalization, integration, forgetting, and consolidation. PMID:25484909

  1. Effects of Filtering the Angular Motion of the Crankshaft on the Estimation of the Instantaneous Engine Friction Torque

    NASA Astrophysics Data System (ADS)

    NEHME, H. K.; CHALHOUB, N. G.; HENEIN, N. A.

    2000-10-01

    The focus of this study is to investigate the effects of filtering the actual angular displacement, velocity and acceleration of the crankshaft on the computation of the instantaneous engine friction torque. These effects are isolated from those of measurement errors and/or noise by relying on a detailed model of the crank-slider mechanism to generate the rigid and flexible motions of the piston/connecting-rod/crankshaft mechanism along with the engine friction torque. The (P-ω) method is used herein to estimate the instantaneous engine friction torque based on the actual and the filtered angular displacement, velocity and acceleration of the crankshaft. The digital simulation results have demonstrated that the (P-ω) method cannot produce an acceptable estimation of the instantaneous engine friction torque in spite of filtering the actual angular motion of the crankshaft. It should be mentioned that the low-pass filter is commonly implemented to attenuate the measurement noise and the effects of structural deformations on the measured angular velocity of the crankshaft. However, the ineffectiveness of the low-pass filter stems from the non-linearities of the crank-slider mechanism that induced superharmonic and combination resonance frequencies in the angular displacement, velocity and acceleration of the crankshaft. The filter has severely attenuated some of the superharmonic resonance frequencies, which constitute an important part of the rigid-body behavior of the crankshaft that is needed by the (P-ω) method to accurately predict the engine friction torque. Moreover, the filtered signals would still be contaminated by the combination resonance frequencies that may appear in the low-frequency range commonly assumed to be dominated by the frequency components of the rigid-body motion of the crankshaft.

  2. Effects of river discharge on abundance and instantaneous growth of age-0 carpsuckers in the Oconee River, Georgia, USA

    USGS Publications Warehouse

    Peterson, Ronald C.; Jennings, C.A.

    2007-01-01

    The Oconee River in middle Georgia, U.S.A., has been regulated by the Sinclair Dam since 1953. Since then, the habitat of the lower Oconee River has been altered and the river has become more incised. The altered environmental conditions of the Oconee River may limit the success of various fish populations. Some obligate riverine fishes may be good indicator species for assessing river system integrity because they are intolerant to unfavourable conditions. For example, many sucker species require clean gravel for feeding and reproduction. Further, age-0 fishes are more vulnerable than adults to flow alterations because of their limited ability to react to such conditions. In this study, we investigated the relationship between abundance and growth of age-0 carpsuckers to river discharge in the Oconee River. A beach seine was used to collect age-0 carpsuckers (Carpiodes spp.) from littoral zones of the lower Oconee River from May through July of 1995 to 2001. Regression models were used to assess whether 12 river discharge categories (e.g. peak, low, seasonal flows) influenced age-0 carpsucker abundance or instantaneous growth. Our analysis indicated that abundance of age-0 carpsuckers was significantly negatively related to number of days river discharge was >85 m3 s-1(r2=0.61, p=0.04). Estimates of instantaneous growth ranged from 0.10 to 0.90. Instantaneous growth rates were significantly positively related to summer river discharge (r2=0.95, p<0.01). These results suggest that (1) moderate flows during spawning and rearing are important for producing strong-year classes of carpsuckers, and (2) river discharge is variable among years, with suitable flows for strong year-classes of carpsuckers occurring every few years. River management should attempt to regulate river discharge to simulate historic flows typical for the region when possible. Such an approach is best achieved when regional climatic conditions are considered.

  3. Development of Shunt-Type Three-Phase Active Power Filter with Novel Adaptive Control for Wind Generators

    PubMed Central

    Chen, Ming-Hung

    2015-01-01

    This paper proposes a new adaptive filter for wind generators that combines instantaneous reactive power compensation technology and current prediction controller, and therefore this system is characterized by low harmonic distortion, high power factor, and small DC-link voltage variations during load disturbances. The performance of the system was first simulated using MATLAB/Simulink, and the possibility of an adaptive digital low-pass filter eliminating current harmonics was confirmed in steady and transient states. Subsequently, a digital signal processor was used to implement an active power filter. The experimental results indicate, that for the rated operation of 2 kVA, the system has a total harmonic distortion of current less than 5.0% and a power factor of 1.0 on the utility side. Thus, the transient performance of the adaptive filter is superior to the traditional digital low-pass filter and is more economical because of its short computation time compared with other types of adaptive filters. PMID:26451391

  4. Development of Shunt-Type Three-Phase Active Power Filter with Novel Adaptive Control for Wind Generators.

    PubMed

    Chen, Ming-Hung

    2015-01-01

    This paper proposes a new adaptive filter for wind generators that combines instantaneous reactive power compensation technology and current prediction controller, and therefore this system is characterized by low harmonic distortion, high power factor, and small DC-link voltage variations during load disturbances. The performance of the system was first simulated using MATLAB/Simulink, and the possibility of an adaptive digital low-pass filter eliminating current harmonics was confirmed in steady and transient states. Subsequently, a digital signal processor was used to implement an active power filter. The experimental results indicate, that for the rated operation of 2 kVA, the system has a total harmonic distortion of current less than 5.0% and a power factor of 1.0 on the utility side. Thus, the transient performance of the adaptive filter is superior to the traditional digital low-pass filter and is more economical because of its short computation time compared with other types of adaptive filters.

  5. Development of Shunt-Type Three-Phase Active Power Filter with Novel Adaptive Control for Wind Generators.

    PubMed

    Chen, Ming-Hung

    2015-01-01

    This paper proposes a new adaptive filter for wind generators that combines instantaneous reactive power compensation technology and current prediction controller, and therefore this system is characterized by low harmonic distortion, high power factor, and small DC-link voltage variations during load disturbances. The performance of the system was first simulated using MATLAB/Simulink, and the possibility of an adaptive digital low-pass filter eliminating current harmonics was confirmed in steady and transient states. Subsequently, a digital signal processor was used to implement an active power filter. The experimental results indicate, that for the rated operation of 2 kVA, the system has a total harmonic distortion of current less than 5.0% and a power factor of 1.0 on the utility side. Thus, the transient performance of the adaptive filter is superior to the traditional digital low-pass filter and is more economical because of its short computation time compared with other types of adaptive filters. PMID:26451391

  6. Applications of Electron Spin Resonance Spectrometry for Reactive Oxygen Species and Reactive Nitrogen Species Research

    PubMed Central

    Kohno, Masahiro

    2010-01-01

    Electron spin resonance (ESR) spectroscopy has been widely applied in the research of biological free radicals for quantitative and qualitative analyses of reactive oxygen species (ROS) and reactive nitrogen species (RNS). The ESR spin-trapping method was developed in the early 1970s and enabled the analysis of short-lived free radicals. This method is now widely used as one of the most powerful tools for free radical studies. In this report, some of the studies that applied ESR for the measurement of ROS and RNS during oxidative stress are discussed. PMID:20664724

  7. Reactive Air Aluminization

    SciTech Connect

    Choi, Jung-Pyung; Chou, Y. S.; Stevenson, Jeffry W.

    2011-10-28

    Ferritic stainless steels and other alloys are of great interest to SOFC developers for applications such as interconnects, cell frames, and balance of plant components. While these alloys offer significant advantages (e.g., low material and manufacturing cost, high thermal conductivity, and high temperature oxidation resistance), there are challenges which can hinder their utilization in SOFC systems; these challenges include Cr volatility and reactivity with glass seals. To overcome these challenges, protective coatings and surface treatments for the alloys are under development. In particular, aluminization of alloy surfaces offers the potential for mitigating both evaporation of Cr from the alloy surface and reaction of alloy constituents with glass seals. Commercial aluminization processes are available to SOFC developers, but they tend to be costly due to their use of exotic raw materials and/or processing conditions. As an alternative, PNNL has developed Reactive Air Aluminization (RAA), which offers a low-cost, simpler alternative to conventional aluminization methods.

  8. [Reactive arthritis. A review].

    PubMed

    Gutiérrez, F; Espinoza, L R

    1990-07-01

    The arthritides that meet the definition or reactive arthritis include the so-called seronegative spondyloarthropathies. Patients are usually aged less than thirty-two. Preceding infection is generally intestinal or venereal, although the involved agent may remain unknown. Enteric forms occur in small epidemics, whereas venereal forms correlate with a recent new sexual partner. The clinical picture varies in severity, with manifestations overlapping between disorders, and often the first complaint is extra-articular. Highly suggestive of reactive arthritis is "sausage" deformity of fingers and toes, pain and stiffness about multiple joints accompanied by radiating lower back discomfort, and enthesitis, particularly at the Achilles tendon. One out of six or seven patients becomes disabled; therapy aimed at preventing disability is vital since medication has little effect on spinal involvement. Antibiotic therapy may be effective in cases in which specific etiologic agents are well defined.

  9. Phenylethynyl Containing Reactive Additives

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor); Hergenrother, Paul M. (Inventor)

    2002-01-01

    Phenylethynyl containing reactive additives were prepared from aromatic diamine, containing phenylethvnvl groups and various ratios of phthalic anhydride and 4-phenylethynviphthalic anhydride in glacial acetic acid to form the imide in one step or in N-methyl-2-pvrrolidinone to form the amide acid intermediate. The reactive additives were mixed in various amounts (10% to 90%) with oligomers containing either terminal or pendent phenylethynyl groups (or both) to reduce the melt viscosity and thereby enhance processability. Upon thermal cure, the additives react and become chemically incorporated into the matrix and effect an increase in crosslink density relative to that of the host resin. This resultant increase in crosslink density has advantageous consequences on the cured resin properties such as higher glass transition temperature and higher modulus as compared to that of the host resin.

  10. Fabric softeners: nearly instantaneous characterization and quality control of cationic surfactants by easy ambient sonic-spray ionization mass spectrometry.

    PubMed

    Saraiva, Sérgio A; Abdelnur, Patrícia V; Catharino, Rodrigo R; Nunes, George; Eberlin, Marcos N

    2009-02-01

    A tiny droplet of typical samples of fabric softeners from different commercial brands placed on a smooth paper surface was subjected to easy ambient sonic-spray ionization mass spectrometry (EASI-MS). With no need for sample-preparation or pre-separation procedures, EASI-MS and EASI-MS/MS identify nearly instantaneously the main surfactants and the homologous series employed in their formulations. Adulterated and low quality samples containing no or less efficient softeners are also easily recognized. PMID:19127530

  11. Inferring Instantaneous, Multivariate and Nonlinear Sensitivities for the Analysis of Feedback Processes in a Dynamical System: Lorenz Model Case Study

    NASA Technical Reports Server (NTRS)

    Aires, Filipe; Rossow, William B.; Hansen, James E. (Technical Monitor)

    2001-01-01

    A new approach is presented for the analysis of feedback processes in a nonlinear dynamical system by observing its variations. The new methodology consists of statistical estimates of the sensitivities between all pairs of variables in the system based on a neural network modeling of the dynamical system. The model can then be used to estimate the instantaneous, multivariate and nonlinear sensitivities, which are shown to be essential for the analysis of the feedbacks processes involved in the dynamical system. The method is described and tested on synthetic data from the low-order Lorenz circulation model where the correct sensitivities can be evaluated analytically.

  12. Instantaneous 2D Velocity and Temperature Measurements in High Speed Flows Based on Spectrally Resolved Molecular Rayleigh Scattering

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.

    1995-01-01

    A Rayleigh scattering diagnostic for high speed flows is described for the simultaneous, instantaneous measurement of gas temperature and velocity at a number (up to about one hundred) of locations in a plane illuminated by an injection-seeded, frequency doubled Nd:YAG laser. Molecular Rayleigh scattered light is collected and passed through a planar mirror Fabry-Perot interferometer. The resulting image is analyzed to determine the gas temperature and bulk velocity at each of the regions. The Cramer Rao lower bound for measurement uncertainty is calculated. Experimental data is presented for a free jet and for preliminary measurements in the Lewis 4 inch by 10 inch supersonic wind tunnel.

  13. Reactivation of latent melioidosis.

    PubMed

    Johnson, A B; Ali, N

    1990-09-01

    Reports of melioidosis in residents of European countries are rare. We describe a case of reactivation of latent melioidosis in a United Kingdom resident. The case demonstrates the lack of clinical response to chemotherapy despite proven in vitro sensitivity of the organism to the drugs used. It is important to consider melioidosis as a cause of septicaemic illness in patients who have travelled to, or been resident in South-East Asia.

  14. Reactivation of latent melioidosis.

    PubMed Central

    Johnson, A. B.; Ali, N.

    1990-01-01

    Reports of melioidosis in residents of European countries are rare. We describe a case of reactivation of latent melioidosis in a United Kingdom resident. The case demonstrates the lack of clinical response to chemotherapy despite proven in vitro sensitivity of the organism to the drugs used. It is important to consider melioidosis as a cause of septicaemic illness in patients who have travelled to, or been resident in South-East Asia. PMID:2235805

  15. SIMULATE-4 pin power calculations

    SciTech Connect

    Bahadir, T.; Lindahl, S. Oe

    2006-07-01

    A new pin power reconstruction module has been implemented in Studsvik Scandpower's next generation nodal code, SIMULATE-4. Heterogeneous pin powers are calculated by modulating multi-group pin powers from the sub-mesh solver of SIMULATE-4 with pin form factors from single-assembly CASMO-5 lattice calculations. The multi-group pin power model captures instantaneous spectral effects, and actinide tracking on the assembly sub-mesh describes exposure-induced pin power variations. Model details and verification tests against high order multi-assembly transport methods are presented. The accuracy of the new methods is also demonstrated by comparing SIMULATE-4 calculations with measured critical experiment pin powers. (authors)

  16. Multiscale reactive molecular dynamics

    PubMed Central

    Knight, Chris; Lindberg, Gerrick E.; Voth, Gregory A.

    2012-01-01

    Many processes important to chemistry, materials science, and biology cannot be described without considering electronic and nuclear-level dynamics and their coupling to slower, cooperative motions of the system. These inherently multiscale problems require computationally efficient and accurate methods to converge statistical properties. In this paper, a method is presented that uses data directly from condensed phase ab initio simulations to develop reactive molecular dynamics models that do not require predefined empirical functions. Instead, the interactions used in the reactive model are expressed as linear combinations of interpolating functions that are optimized by using a linear least-squares algorithm. One notable benefit of the procedure outlined here is the capability to minimize the number of parameters requiring nonlinear optimization. The method presented can be generally applied to multiscale problems and is demonstrated by generating reactive models for the hydrated excess proton and hydroxide ion based directly on condensed phase ab initio molecular dynamics simulations. The resulting models faithfully reproduce the water-ion structural properties and diffusion constants from the ab initio simulations. Additionally, the free energy profiles for proton transfer, which is sensitive to the structural diffusion of both ions in water, are reproduced. The high fidelity of these models to ab initio simulations will permit accurate modeling of general chemical reactions in condensed phase systems with computational efficiency orders of magnitudes greater than currently possible with ab initio simulation methods, thus facilitating a proper statistical sampling of the coupling to slow, large-scale motions of the system. PMID:23249062

  17. Becoming Reactive by Concretization

    NASA Technical Reports Server (NTRS)

    Prieditis, Armand; Janakiraman, Bhaskar

    1992-01-01

    One way to build a reactive system is to construct an action table indexed by the current situation or stimulus. The action table describes what course of action to pursue for each situation or stimulus. This paper describes an incremental approach to constructing the action table through achieving goals with a hierarchical search system. These hierarchies are generated with transformations called concretizations, which add constraints to a problem and which can reduce the search space. The basic idea is that an action for a state is looked up in the action table and executed whenever the action table has an entry for that state; otherwise, a path is found to the nearest (cost-wise in a graph with costweighted arcs) state that has a mappring from a state in the next highest hierarchy. For each state along the solution path, the successor state in the path is cached in the action table entry for that state. Without caching, the hierarchical search system can logarithmically reduce search. When the table is complete the system no longer searches: it simply reacts by proceeding to the state listed in the table for each state. Since the cached information is specific only to the nearest state in the next highest hierarchy and not the goal, inter-goal transfer of reactivity is possible. To illustrate our approach, we show how an implemented hierarchical search system can completely reactive.

  18. Comparison between the measured and calculated reactivity in measuring the effectiveness of the emergency protection at the stage of physical start-up of unit no. 3 at the Kalinin nuclear power plant

    NASA Astrophysics Data System (ADS)

    Kavun, O. Yu.; Popykin, A. I.; Shevchenko, R. A.; Shevchenko, S. A.

    2012-12-01

    This paper presents comparisons between the effectiveness of the emergency protection under both stationary and nonstationary formulations calculated with the use of the RADUGA-7.5 package [1] and experimental data obtained in measuring the "weight" of the emergency protection in the process of physical start-up of the VVER-1000 reactor of unit no. 3 of the Kalinin NPP. On the basis of the results obtained, recommendations are given on comparing the measured and calculated reactivity and parameters determined by using its value.

  19. Simulation of the instantaneous free piston Stirling engine-electrical load interaction

    SciTech Connect

    Mehdizadeh, N.S.; Stouffs, P.

    1998-07-01

    In this paper the authors consider a gamma type free piston engine (that is, a configuration with a power piston cylinder and a separate displacer cylinder) with the MARTINI configuration (that is, with a free piston but a kinematically driven displacer). In the modeled engine, the displacer is driven by an electrical motor and there are two symmetrical, free, power pistons. This configuration ensures a complete balancing of the engine. The free pistons bear the moving parts of the linear electric alternators. This engine may be considered for solar to electrical energy conversion for land or space applications, for instance. A dynamic simulation of this engine has been developed using a decoupled analysis. The motion equation of the free piston induces a strong coupling between the electrical load and the thermodynamics inside the free piston Stirling engine. From the thermodynamics point of view, the piston-displacer phase lag is an important parameter. It is shown that if the electrical circuit elements (R-L-C) are constants, the phase lag between the free pistons and displacer motions is far from the optimum. However this phase lag can be controlled by means of a variable electrical resistance. For both cases of stand-alone engine with an independent electrical load, or grid-connected engine, it is shown how one can in a very simple way multiply the net electrical power by a factor 4 to 10 and the efficiency by a factor 1.25 to 2 without any engine geometry modification.

  20. Raman backscatter as a remote laser power sensor in high-energy-density plasmas.

    PubMed

    Moody, J D; Strozzi, D J; Divol, L; Michel, P; Robey, H F; LePape, S; Ralph, J; Ross, J S; Glenzer, S H; Kirkwood, R K; Landen, O L; MacGowan, B J; Nikroo, A; Williams, E A

    2013-07-12

    Stimulated Raman backscatter is used as a remote sensor to quantify the instantaneous laser power after transfer from outer to inner cones that cross in a National Ignition Facility (NIF) gas-filled hohlraum plasma. By matching stimulated Raman backscatter between a shot reducing outer versus a shot reducing inner power we infer that about half of the incident outer-cone power is transferred to inner cones, for the specific time and wavelength configuration studied. This is the first instantaneous nondisruptive measure of power transfer in an indirect drive NIF experiment using optical measurements. PMID:23889410

  1. Derivation of Instantaneous Wye and Zero-Phase Sequence Voltages from Line-Line Voltages in Unbalanced 3-Phase 3-Wire Systems and Application of This Method to 3-Phase PWM Converter Control

    NASA Astrophysics Data System (ADS)

    Yuzurihara, Itsuo; Kawamura, Atsuo

    In general, voltage imbalances in 3-phase AC power systems are inevitable. 3-Phase PWM (Pulse Width Modulation) converter used in 3-wire systems are generally designed for use under limited imbalances of input voltages, and problems such as input current distortion, deterioration of output properties, degradation of efficiency and failure may occur in some cases. These problems cause severe damages to industries in some cases, for example, semiconductor production machines: SEMI defined “SEMI F47-0200” and “SEMI F47-0706” standards that have to be satisfied to realize voltage sag immunity. In order to compensate the remained problems due to the unbalanced input voltages, particular storage devices are designed additionally for conventional converters. This paper proposes that the determination of both the instantaneous zero-phase sequence voltage and wye voltages is essential for 3-phase PWM converter control used for a 3-wire system to keep its output rated under occasional or long-term voltage imbalances in an AC system. This paper also describes a general new method to derive the components of the voltages of instantaneous wye and zero-phase sequence voltage from line-line voltages of a 3-wire system. This paper also describes a method to apply the voltages to control the converter. The results obtained on implementation verify that this new converter keeps its output rated under unbalanced conditions wider than those defined by SEMIs without particular storage devices as far as the AC voltages are remained live.

  2. Point of optimal kinematic error: improvement of the instantaneous helical pivot method for locating centers of rotation.

    PubMed

    De Rosario, Helios; Page, Alvaro; Mata, Vicente

    2014-05-01

    This paper proposes a variation of the instantaneous helical pivot technique for locating centers of rotation. The point of optimal kinematic error (POKE), which minimizes the velocity at the center of rotation, may be obtained by just adding a weighting factor equal to the square of angular velocity in Woltring׳s equation of the pivot of instantaneous helical axes (PIHA). Calculations are simplified with respect to the original method, since it is not necessary to make explicit calculations of the helical axis, and the effect of accidental errors is reduced. The improved performance of this method was validated by simulations based on a functional calibration task for the gleno-humeral joint center. Noisy data caused a systematic dislocation of the calculated center of rotation towards the center of the arm marker cluster. This error in PIHA could even exceed the effect of soft tissue artifacts associated to small and medium deformations, but it was successfully reduced by the POKE estimation. PMID:24650972

  3. Model-driven requirements engineering (MDRE) for real-time ultra-wide instantaneous bandwidth signal simulation

    NASA Astrophysics Data System (ADS)

    Chang, Daniel Y.; Rowe, Neil C.

    2013-05-01

    While conducting a cutting-edge research in a specific domain, we realize that (1) requirements clarity and correctness are crucial to our success [1], (2) hardware is hard to change, most work is in software requirements development, coding and testing [2], (3) requirements are constantly changing, so that configurability, reusability, scalability, adaptability, modularity and testability are important non-functional attributes [3], (4) cross-domain knowledge is necessary for complex systems [4], and (5) if our research is successful, the results could be applied to other domains with similar problems. In this paper, we propose to use model-driven requirements engineering (MDRE) to model and guide our requirements/development, since models are easy to understand, execute, and modify. The domain for our research is Electronic Warfare (EW) real-time ultra-wide instantaneous bandwidth (IBW1) signal simulation. The proposed four MDRE models are (1) Switch-and-Filter architecture, (2) multiple parallel data bit streams alignment, (3) post-ADC and pre-DAC bits re-mapping, and (4) Discrete Fourier Transform (DFT) filter bank. This research is unique since the instantaneous bandwidth we are dealing with is in gigahertz range instead of conventional megahertz.

  4. Analytical model for instantaneous lift and shape deformation of an insect-scale flapping wing in hover.

    PubMed

    Kang, Chang-kwon; Shyy, Wei

    2014-12-01

    In the analysis of flexible flapping wings of insects, the aerodynamic outcome depends on the combined structural dynamics and unsteady fluid physics. Because the wing shape and hence the resulting effective angle of attack are a priori unknown, predicting aerodynamic performance is challenging. Here, we show that a coupled aerodynamics/structural dynamics model can be established for hovering, based on a linear beam equation with the Morison equation to account for both added mass and aerodynamic damping effects. Lift strongly depends on the instantaneous angle of attack, resulting from passive pitch associated with wing deformation. We show that both instantaneous wing deformation and lift can be predicted in a much simplified framework. Moreover, our analysis suggests that resulting wing kinematics can be explained by the interplay between acceleration-related and aerodynamic damping forces. Interestingly, while both forces combine to create a high angle of attack resulting in high lift around the midstroke, they offset each other for phase control at the end of the stroke.

  5. Analytical model for instantaneous lift and shape deformation of an insect-scale flapping wing in hover

    PubMed Central

    Kang, Chang-kwon; Shyy, Wei

    2014-01-01

    In the analysis of flexible flapping wings of insects, the aerodynamic outcome depends on the combined structural dynamics and unsteady fluid physics. Because the wing shape and hence the resulting effective angle of attack are a priori unknown, predicting aerodynamic performance is challenging. Here, we show that a coupled aerodynamics/structural dynamics model can be established for hovering, based on a linear beam equation with the Morison equation to account for both added mass and aerodynamic damping effects. Lift strongly depends on the instantaneous angle of attack, resulting from passive pitch associated with wing deformation. We show that both instantaneous wing deformation and lift can be predicted in a much simplified framework. Moreover, our analysis suggests that resulting wing kinematics can be explained by the interplay between acceleration-related and aerodynamic damping forces. Interestingly, while both forces combine to create a high angle of attack resulting in high lift around the midstroke, they offset each other for phase control at the end of the stroke. PMID:25297319

  6. Instantaneous velocity displacement and contour measurement by use of shadow moiré and temporal wavelet analysis.

    PubMed

    Tay, Cho Jui; Quan, Chenggen; Fu, Yu; Huang, Yuanhao

    2004-07-20

    A temporal wavelet analysis method is proposed for velocity, displacement, and three-dimensional surface-profile measurement of a continuously deforming object by use of the shadow moiré technique. A grating is placed close to a deforming object, and its shadow is observed through the grating. The moiré fringe patterns, generated by the interference of the grating lines and their shadows, are captured by a high-speed CCD camera with a telecentric gauging lens. Instantaneous frequency of gray-value variation is evaluated point by point with the continuous wavelet transform. From the instantaneous frequency of each point on the object, the velocity, displacement, and high-quality surface profile at different instants can be retrieved. In this application, two specimens are tested to demonstrate the validity of the proposed method: One is a small coin with a rigid body motion, and the other is a simply supported beam subjected to a central point load. The results are compared with those obtained from temporal Fourier-transform and mechanical stylus methods. PMID:15291059

  7. Analytical model for instantaneous lift and shape deformation of an insect-scale flapping wing in hover.

    PubMed

    Kang, Chang-kwon; Shyy, Wei

    2014-12-01

    In the analysis of flexible flapping wings of insects, the aerodynamic outcome depends on the combined structural dynamics and unsteady fluid physics. Because the wing shape and hence the resulting effective angle of attack are a priori unknown, predicting aerodynamic performance is challenging. Here, we show that a coupled aerodynamics/structural dynamics model can be established for hovering, based on a linear beam equation with the Morison equation to account for both added mass and aerodynamic damping effects. Lift strongly depends on the instantaneous angle of attack, resulting from passive pitch associated with wing deformation. We show that both instantaneous wing deformation and lift can be predicted in a much simplified framework. Moreover, our analysis suggests that resulting wing kinematics can be explained by the interplay between acceleration-related and aerodynamic damping forces. Interestingly, while both forces combine to create a high angle of attack resulting in high lift around the midstroke, they offset each other for phase control at the end of the stroke. PMID:25297319

  8. Comparison of Instantaneous Frequency Scaling from Rain Attenuation and Optical Disdrometer Measurements at K/Q bands

    NASA Technical Reports Server (NTRS)

    Nessel, James; Zemba, Michael; Luini, Lorenzo; Riva, Carlo

    2015-01-01

    Rain attenuation is strongly dependent on the rain rate, but also on the rain drop size distribution (DSD). Typically, models utilize an average drop size distribution, such as those developed by Laws and Parsons, or Marshall and Palmer. However, individual rain events may possess drop size distributions which could be significantly different from the average and will impact, for example, fade mitigation techniques which utilize channel performance estimates from a signal at a different frequency. Therefore, a good understanding of the characteristics and variability of the raindrop size distribution is extremely important in predicting rain attenuation and instantaneous frequency scaling parameters on an event-toevent basis. Since June 2014, NASA Glenn Research Center (GRC) and the Politecnico di Milano (POLIMI) have measured the attenuation due to rain in Milan, Italy, on the 20/40 GHz beacon signal broadcast from the Alphasat TDP#5 Aldo Paraboni Q/V-band Payload. Concomitant with these measurements are the measurements of drop size distribution and rain rate utilizing a Thies Clima laser precipitation monitor (disdrometer). In this paper, we discuss the comparison of the predicted rain attenuation at 20 and 40 GHz derived from the drop size distribution data with the measured rain attenuation. The results are compared on statistical and real-time bases. We will investigate the performance of the rain attenuation model, instantaneous frequency scaling, and the distribution of the scaling factor. Further, seasonal rain characteristics will be analysed.

  9. Evaluating the design of satellite scanning radiometers for earth radiation budget measurements with system simulations. Part 1: Instantaneous estimates

    NASA Technical Reports Server (NTRS)

    Stowe, Larry; Ardanuy, Philip; Hucek, Richard; Abel, Peter; Jacobowitz, Herbert

    1991-01-01

    A set of system simulations was performed to evaluate candidate scanner configurations to fly as a part of the Earth Radiation Budget Instrument (ERBI) on the polar platforms during the 1990's. The simulation is considered of instantaneous sampling (without diurnal averaging) of the longwave and shortwave fluxes at the top of the atmosphere (TOA). After measurement and subsequent inversion to the TOA, the measured fluxes were compared to the reference fluxes for 2.5 deg lat/long resolution targets. The reference fluxes at this resolution are obtained by integrating over the 25 x 25 = 625 grid elements in each target. The differences between each of these two resultant spatially averaged sets of target measurements (errors) are taken and then statistically summarized. Five instruments are considered: (1) the Conically Scanning Radiometer (CSR); (2) the ERBE Cross Track Scanner; (3) the Nimbus-7 Biaxial Scanner; (4) the Clouds and Earth's Radiant Energy System Instrument (CERES-1); and (5) the Active Cavity Array (ACA). Identical studies of instantaneous error were completed for many days, two seasons, and several satellite equator crossing longitudes. The longwave flux errors were found to have the same space and time characteristics as for the shortwave fluxes, but the errors are only about 25 pct. of the shortwave errors.

  10. Instantaneous mode contamination and parametric combination instability of spinning cyclically symmetric ring structures with expanding application to planetary gear ring

    NASA Astrophysics Data System (ADS)

    Wang, Shiyu; Sun, Wenjia; Wang, Yaoyao

    2016-08-01

    This work addresses the free and parametric elastic vibrations of the spinning cyclically symmetric ring structures. The focus is on the instantaneous mode contamination, parametric combination instability and their connections. An analytical model is developed by using the Hamilton's principle for the in-plane bending deflection, the distinction of which is in the arbitrary distributions of the attached mass and stiffness. A special case with equally-spaced discrete mass particles and spinning springs is detailed. The uneven tangential force and the time-invariant deflection caused by the mass particles are formulated. The results imply that the order of such deflection is equal to the number of the mass particles. The instantaneous mode contamination and parametric combination instability are captured by the perturbation and superposition mode shapes of the stationary smooth ring by introducing complex coefficients. The contamination rule is similar to that of the stationary structure but the contamination strength is time-variant due to the spinning springs. New analytical results and quantitative explanations on the contamination and instability especially their connections are presented. As an application of the proposed method, the free and parametric vibrations of the planetary gear ring are formulated. Main results are demonstrated by means of the numerical simulations and compared with the existing studies.

  11. Characterization of depressive States in bipolar patients using wearable textile technology and instantaneous heart rate variability assessment.

    PubMed

    Valenza, Gaetano; Citi, Luca; Gentili, Claudio; Lanata, Antonio; Scilingo, Enzo Pasquale; Barbieri, Riccardo

    2015-01-01

    The analysis of cognitive and autonomic responses to emotionally relevant stimuli could provide a viable solution for the automatic recognition of different mood states, both in normal and pathological conditions. In this study, we present a methodological application describing a novel system based on wearable textile technology and instantaneous nonlinear heart rate variability assessment, able to characterize the autonomic status of bipolar patients by considering only electrocardiogram recordings. As a proof of this concept, our study presents results obtained from eight bipolar patients during their normal daily activities and being elicited according to a specific emotional protocol through the presentation of emotionally relevant pictures. Linear and nonlinear features were computed using a novel point-process-based nonlinear autoregressive integrative model and compared with traditional algorithmic methods. The estimated indices were used as the input of a multilayer perceptron to discriminate the depressive from the euthymic status. Results show that our system achieves much higher accuracy than the traditional techniques. Moreover, the inclusion of instantaneous higher order spectra features significantly improves the accuracy in successfully recognizing depression from euthymia.

  12. Evaluating the design of satellite scanning radiometers for earth radiation budget measurements with system simulations. Part 1: Instantaneous estimates

    NASA Astrophysics Data System (ADS)

    Stowe, Larry; Ardanuy, Philip; Hucek, Richard; Abel, Peter; Jacobowitz, Herbert

    1991-10-01

    A set of system simulations was performed to evaluate candidate scanner configurations to fly as a part of the Earth Radiation Budget Instrument (ERBI) on the polar platforms during the 1990's. The simulation is considered of instantaneous sampling (without diurnal averaging) of the longwave and shortwave fluxes at the top of the atmosphere (TOA). After measurement and subsequent inversion to the TOA, the measured fluxes were compared to the reference fluxes for 2.5 deg lat/long resolution targets. The reference fluxes at this resolution are obtained by integrating over the 25 x 25 = 625 grid elements in each target. The differences between each of these two resultant spatially averaged sets of target measurements (errors) are taken and then statistically summarized. Five instruments are considered: (1) the Conically Scanning Radiometer (CSR); (2) the ERBE Cross Track Scanner; (3) the Nimbus-7 Biaxial Scanner; (4) the Clouds and Earth's Radiant Energy System Instrument (CERES-1); and (5) the Active Cavity Array (ACA). Identical studies of instantaneous error were completed for many days, two seasons, and several satellite equator crossing longitudes. The longwave flux errors were found to have the same space and time characteristics as for the shortwave fluxes, but the errors are only about 25 pct. of the shortwave errors.

  13. Nonlinear digital signal processing in mental health: characterization of major depression using instantaneous entropy measures of heartbeat dynamics

    PubMed Central

    Valenza, Gaetano; Garcia, Ronald G.; Citi, Luca; Scilingo, Enzo P.; Tomaz, Carlos A; Barbieri, Riccardo

    2015-01-01

    Nonlinear digital signal processing methods that address system complexity have provided useful computational tools for helping in the diagnosis and treatment of a wide range of pathologies. More specifically, nonlinear measures have been successful in characterizing patients with mental disorders such as Major Depression (MD). In this study, we propose the use of instantaneous measures of entropy, namely the inhomogeneous point-process approximate entropy (ipApEn) and the inhomogeneous point-process sample entropy (ipSampEn), to describe a novel characterization of MD patients undergoing affective elicitation. Because these measures are built within a nonlinear point-process model, they allow for the assessment of complexity in cardiovascular dynamics at each moment in time. Heartbeat dynamics were characterized from 48 healthy controls and 48 patients with MD while emotionally elicited through either neutral or arousing audiovisual stimuli. Experimental results coming from the arousing tasks show that ipApEn measures are able to instantaneously track heartbeat complexity as well as discern between healthy subjects and MD patients. Conversely, standard heart rate variability (HRV) analysis performed in both time and frequency domains did not show any statistical significance. We conclude that measures of entropy based on nonlinear point-process models might contribute to devising useful computational tools for care in mental health. PMID:25821435

  14. Nonlinear digital signal processing in mental health: characterization of major depression using instantaneous entropy measures of heartbeat dynamics.

    PubMed

    Valenza, Gaetano; Garcia, Ronald G; Citi, Luca; Scilingo, Enzo P; Tomaz, Carlos A; Barbieri, Riccardo

    2015-01-01

    Nonlinear digital signal processing methods that address system complexity have provided useful computational tools for helping in the diagnosis and treatment of a wide range of pathologies. More specifically, nonlinear measures have been successful in characterizing patients with mental disorders such as Major Depression (MD). In this study, we propose the use of instantaneous measures of entropy, namely the inhomogeneous point-process approximate entropy (ipApEn) and the inhomogeneous point-process sample entropy (ipSampEn), to describe a novel characterization of MD patients undergoing affective elicitation. Because these measures are built within a nonlinear point-process model, they allow for the assessment of complexity in cardiovascular dynamics at each moment in time. Heartbeat dynamics were characterized from 48 healthy controls and 48 patients with MD while emotionally elicited through either neutral or arousing audiovisual stimuli. Experimental results coming from the arousing tasks show that ipApEn measures are able to instantaneously track heartbeat complexity as well as discern between healthy subjects and MD patients. Conversely, standard heart rate variability (HRV) analysis performed in both time and frequency domains did not show any statistical significance. We conclude that measures of entropy based on nonlinear point-process models might contribute to devising useful computational tools for care in mental health.

  15. APR1400 Reactivity Insertion Accident Analysis Using KNAP

    SciTech Connect

    Chang-Keun, Yang; Yo-Han, Kim; Chang-Kyung, Sung

    2006-07-01

    The Korea Electric Power Research Institute had decided to develop the new safety analysis code system for the Optimized Power Reactor 1000 (OPR1000) in Korea by the fund of the Ministry of Commerce, Industry and Energy. In this paper, some results of the Advanced Power Reactor 1400(APR1400) using the RETRAN code for some reactivity insertion accident are introduced to expand application from safety analysis experience of OPR1000. (authors)

  16. Deferasirox is a powerful NF-κB inhibitor in myelodysplastic cells and in leukemia cell lines acting independently from cell iron deprivation by chelation and reactive oxygen species scavenging

    PubMed Central

    Messa, Emanuela; Carturan, Sonia; Maffè, Chiara; Pautasso, Marisa; Bracco, Enrico; Roetto, Antonella; Messa, Francesca; Arruga, Francesca; Defilippi, Ilaria; Rosso, Valentina; Zanone, Chiara; Rotolo, Antonia; Greco, Elisabetta; Pellegrino, Rosa M.; Alberti, Daniele; Saglio, Giuseppe; Cilloni, Daniela

    2010-01-01

    Background Usefulness of iron chelation therapy in myelodysplastic patients is still under debate but many authors suggest its possible role in improving survival of low-risk myelodysplastic patients. Several reports have described an unexpected effect of iron chelators, such as an improvement in hemoglobin levels, in patients affected by myelodysplastic syndromes. Furthermore, the novel chelator deferasirox induces a similar improvement more rapidly. Nuclear factor-κB is a key regulator of many cellular processes and its impaired activity has been described in different myeloid malignancies including myelodysplastic syndromes. Design and Methods We evaluated deferasirox activity on nuclear factor-κB in myelodysplastic syndromes as a possible mechanism involved in hemoglobin improvement during in vivo treatment. Forty peripheral blood samples collected from myelodysplastic syndrome patients were incubated with 50 μM deferasirox for 18h. Results Nuclear factor-κB activity dramatically decreased in samples showing high basal activity as well as in cell lines, whereas no similar behavior was observed with other iron chelators despite a similar reduction in reactive oxygen species levels. Additionally, ferric hydroxyquinoline incubation did not decrease deferasirox activity in K562 cells suggesting the mechanism of action of the drug is independent from cell iron deprivation by chelation. Finally, incubation with both etoposide and deferasirox induced an increase in K562 apoptotic rate. Conclusions Nuclear factor-κB inhibition by deferasirox is not seen from other chelators and is iron and reactive oxygen species scavenging independent. This could explain the hemoglobin improvement after in vivo treatment, such that our hypothesis needs to be validated in further prospective studies. PMID:20534700

  17. Influence of reactive gas admixture on transition metal cluster nucleation in a gas aggregation cluster source

    NASA Astrophysics Data System (ADS)

    Peter, Tilo; Polonskyi, Oleksandr; Gojdka, Björn; Mohammad Ahadi, Amir; Strunskus, Thomas; Zaporojtchenko, Vladimir; Biederman, Hynek; Faupel, Franz

    2012-12-01

    We quantitatively assessed the influence of reactive gases on the formation processes of transition metal clusters in a gas aggregation cluster source. A cluster source based on a 2 in. magnetron is used to study the production rate of titanium and cobalt clusters. Argon served as working gas for the DC magnetron discharge, and a small amount of reactive gas (oxygen and nitrogen) is added to promote reactive cluster formation. We found that the cluster production rate depends strongly on the reactive gas concentration for very small amounts of reactive gas (less than 0.1% of total working gas), and no cluster formation takes place in the absence of reactive species. The influence of discharge power, reactive gas concentration, and working gas pressure are investigated using a quartz micro balance in a time resolved manner. The strong influence of reactive gas is explained by a more efficient formation of nucleation seeds for metal-oxide or nitride than for pure metal.

  18. Direct measurement of instantaneous source speed for a HDR brachytherapy unit using an optical fiber based detector

    SciTech Connect

    Minamisawa, R. A.; Rubo, R. A.; Seraide, R. M.; Rocha, J. R. O.; Almeida, A.

    2010-10-15

    Purpose: Several attempts to determine the transit time of a high dose rate (HDR) brachytherapy unit have been reported in the literature with controversial results. The determination of the source speed is necessary to accurately calculate the transient dose in brachytherapy treatments. In these studies, only the average speed of the source was measured as a parameter for transit dose calculation, which does not account for the realistic movement of the source, and is therefore inaccurate for numerical simulations. The purpose of this work is to report the implementation and technical design of an optical fiber based detector to directly measure the instantaneous speed profile of a {sup 192}Ir source in a Nucletron HDR brachytherapy unit. Methods: To accomplish this task, we have developed a setup that uses the Cerenkov light induced in optical fibers as a detection signal for the radiation source moving inside the HDR catheter. As the {sup 192}Ir source travels between two optical fibers with known distance, the threshold of the induced signals are used to extract the transit time and thus the velocity. The high resolution of the detector enables the measurement of the transit time at short separation distance of the fibers, providing the instantaneous speed. Results: Accurate and high resolution speed profiles of the {sup 192}Ir radiation source traveling from the safe to the end of the catheter and between dwell positions are presented. The maximum and minimum velocities of the source were found to be 52.0{+-}1.0 and 17.3{+-}1.2 cm/s. The authors demonstrate that the radiation source follows a uniformly accelerated linear motion with acceleration of |a|=113 cm/s{sup 2}. In addition, the authors compare the average speed measured using the optical fiber detector to those obtained in the literature, showing deviation up to 265%. Conclusions: To the best of the authors' knowledge, the authors directly measured for the first time the instantaneous speed profile of

  19. Proactive and reactive inhibitory control in rats

    PubMed Central

    Mayse, Jeffrey D.; Nelson, Geoffrey M.; Park, Pul; Gallagher, Michela; Lin, Shih-Chieh

    2014-01-01

    Inhibiting actions inappropriate for the behavioral context, or inhibitory control, is essential for survival and involves both reactively stopping the current prepared action and proactively adjusting behavioral tendencies to increase future performance. A powerful paradigm widely used in basic and clinical research to study inhibitory control is the stop signal task (SST). Recent years have seen a surging interest in translating the SST to rodents to study the neural mechanisms underlying inhibitory control. However, significant differences in task designs and behavioral strategies between rodent and primate studies have made it difficult to directly compare the two literatures. In this study, we developed a rodent-appropriate SST and characterized both reactive and proactive control in rats. For reactive inhibitory control, we found that, unlike in primates, incorrect stop trials in rodents result from two independent types of errors: an initial failure-to-stop error or, after successful stopping, a subsequent failure-to-wait error. Conflating failure-to-stop and failure-to-wait errors systematically overestimates the covert latency of reactive inhibition, the stop signal reaction time (SSRT). To correctly estimate SSRT, we developed and validated a new method that provides an unbiased SSRT estimate independent of the ability to wait. For proactive inhibitory control, we found that rodents adjust both their reaction time and the ability to stop following failure-to-wait errors and successful stop trials, but not after failure-to-stop errors. Together, these results establish a valid rodent model that utilizes proactive and reactive inhibitory control strategies similar to primates, and highlight the importance of dissociating initial stopping from subsequent waiting in studying mechanisms of inhibitory control using rodents. PMID:24847204

  20. The structure of the vorticity field in turbulent channel flow. Part 1: Analysis of instantaneous fields and statistical correlations

    NASA Technical Reports Server (NTRS)

    Moin, P.; Kim, J.

    1984-01-01

    An investigation into the existence of hairpin vortices in turbulent channel flow is conducted using a database generated by the large eddy simulation technique. It is shown that away from the wall the distribution of the inclination angle of vorticity vector attains its maximum at about 45 deg to the wall. Two point correlations of velocity and vorticity fluctuations strongly support a flow model consisting of vortical structures inclined at 45 deg to the wall. The instantaneous vorticity vectors plotted in planes inclined at 45 deg show that the flow contains an appreciable number of hairpins. Vortex lines are used to display the three dimensional structure of hairpins, which are shown to be generated from deformation of transverse vortex filaments.

  1. The instantaneous local transition of a stable equilibrium to a chaotic attractor in piecewise-smooth systems of differential equations

    NASA Astrophysics Data System (ADS)

    Simpson, D. J. W.

    2016-09-01

    An attractor of a piecewise-smooth continuous system of differential equations can bifurcate from a stable equilibrium to a more complicated invariant set when it collides with a switching manifold under parameter variation. Here numerical evidence is provided to show that this invariant set can be chaotic. The transition occurs locally (in a neighbourhood of a point) and instantaneously (for a single critical parameter value). This phenomenon is illustrated for the normal form of a boundary equilibrium bifurcation in three dimensions using parameter values adapted from of a piecewise-linear model of a chaotic electrical circuit. The variation of a secondary parameter reveals a period-doubling cascade to chaos with windows of periodicity. The dynamics is well approximated by a one-dimensional unimodal map which explains the bifurcation structure. The robustness of the attractor is also investigated by studying the influence of nonlinear terms.

  2. Perfume fingerprinting by easy ambient sonic-spray ionization mass spectrometry: nearly instantaneous typification and counterfeit detection.

    PubMed

    Haddad, Renato; Catharino, Rodrigo Ramos; Marques, Lygia Azevedo; Eberlin, Marcos Nogueira

    2008-11-01

    Perfume counterfeiting is an illegal worldwide practice that involves huge economic losses and potential consumer risk. EASI is a simple, easily performed and rapidly implemented desorption/ionization technique for ambient mass spectrometry (MS). Herein we demonstrate that EASI-MS allows nearly instantaneous perfume typification and counterfeit detection. Samples are simply sprayed onto a glass rod or paper surface and, after a few seconds of ambient drying, a profile of the most polar components of the perfume is acquired. These components provide unique and reproducible chemical signatures for authentic perfume samples. Counterfeiting is readily recognized since the exact set and relative proportions of the more polar chemicals, sometimes at low concentrations, are unknown or hard to reproduce by the counterfeiters and hence very distinct and variable EASI-MS profiles are observed for the counterfeit samples.

  3. An Informational Algorithm as the Basis for Perception-Action Control of the Instantaneous Axes of the Knee

    PubMed Central

    Kim, Wangdo; Espanha, Margarida M.; Veloso, António P.; Araújo, Duarte; João, Filipa; Carrão, Luis; Kohles, Sean S.

    2013-01-01

    Traditional locomotion studies emphasize an optimization of the desired movement trajectories while ignoring sensory feedback. We propose an information based theory that locomotion is neither triggered nor commanded but controlled. The basis for this control is the information derived from perceiving oneself in the world. Control therefore lies in the human-environment system. In order to test this hypothesis, we derived a mathematical foundation characterizing the energy that is required to perform a rotational twist, with small amplitude, of the instantaneous axes of the knee (IAK). We have found that the joint’s perception of the ground reaction force may be replaced by the co-perception of muscle activation with appropriate intensities. This approach generated an accurate comparison with known joint forces and appears appropriate in so far as predicting the effect on the knee when it is free to twist about the IAK. PMID:24932433

  4. Highly time-resolved evaluation technique of instantaneous amplitude and phase difference using analytic signals for multi-channel diagnostics.

    PubMed

    Ohshima, S; Kobayashi, S; Yamamoto, S; Nagasaki, K; Mizuuchi, T; Kado, S; Okada, H; Minami, T; Lee, H Y; Zang, L; Kenmochi, N; Kasajima, K; Ohtani, Y; Shi, N; Nagae, Y; Konoshima, S; Sano, F

    2014-11-01

    A fluctuation analysis technique using analytic signals is proposed. Analytic signals are suitable to characterize a single mode with time-dependent amplitude and frequency, such as an MHD mode observed in fusion plasmas since the technique can evaluate amplitude and frequency at a specific moment without limitations of temporal and frequency resolutions, which is problematic in Fourier-based analyses. Moreover, a concept of instantaneous phase difference is newly introduced, and error of the evaluated phase difference and its error reduction techniques using conditional/ensemble averaging are discussed. These techniques are applied to experimental data of the beam emission spectroscopic measurement in the Heliotron J device, which demonstrates that the technique can describe nonlinear evolution of MHD instabilities. This technique is widely applicable to other diagnostics having necessity to evaluate phase difference.

  5. Controlling Material Reactivity Using Architecture.

    PubMed

    Sullivan, Kyle T; Zhu, Cheng; Duoss, Eric B; Gash, Alexander E; Kolesky, David B; Kuntz, Joshua D; Lewis, Jennifer A; Spadaccini, Christopher M

    2016-03-01

    3D-printing methods are used to generate reactive material architectures. Several geometric parameters are observed to influence the resultant flame propagation velocity, indicating that the architecture can be utilized to control reactivity. Two different architectures, channels and hurdles, are generated, and thin films of thermite are deposited onto the surface. The architecture offers an additional route to control, at will, the energy release rate in reactive composite materials. PMID:26669517

  6. Performance of short-time spectral parametric methods for reducing the variance of the Doppler ultrasound mean instantaneous frequency estimation.

    PubMed

    Sava, H; Durand, L G; Cloutier, G

    1999-05-01

    To achieve an accurate estimation of the instantaneous turbulent velocity fluctuations downstream of prosthetic heart valves in vivo, the variability of the spectral method used to measure the mean frequency shift of the Doppler signal (i.e. the Doppler velocity) should be minimised. This paper investigates the performance of various short-time spectral parametric methods such as the short-time Fourier transform, autoregressive modelling based on two different approaches, autoregressive moving average modelling based on the Steiglitz-McBride method, and Prony's spectral method. A simulated Doppler signal was used to evaluate the performance of the above mentioned spectral methods and Gaussian noise was added to obtain a set of signals with various signal-to-noise ratios. Two different parameters were used to evaluate the performance of each method in terms of variability and accurate matching of the theoretical Doppler mean instantaneous frequency variation within the cardiac cycle. Results show that autoregressive modelling outperforms the other investigated spectral techniques for window lengths varying between 1 and 10 ms. Among the autoregressive algorithms implemented, it is shown that the maximum entropy method based on a block data processing technique gives the best results for a signal-to-noise ratio of 20 dB. However, at 10 and 0 dB, the Levinson-Durbin algorithm surpasses the performance of the maximum entropy method. It is expected that the intrinsic variance of the spectral methods can be an important source of error for the estimation of the turbulence intensity. The range of this error varies from 0.38% to 24% depending on the parameters of the spectral method and the signal-to-noise ratio. PMID:10505377

  7. Search for instantaneous radiation near the instant of break momentum of various fissioning nuclear systems at low excitation energies

    SciTech Connect

    Vorobyev, A. S. Val'ski, G. V.; Gagarskii, A. M.; Guseva, I. S.; Petrov, G. A.; Petrova, V. I.; Serebrin, A. Yu.; Sokolov, V. E.; Shcherbakov, O. A.

    2011-12-15

    The main results of studying the properties of 'instantaneous' neutrons and {gamma} photons during the fission of {sup 233,235}U(n{sub th}, f) and {sup 239}Pu(n{sub th}, f) nuclei and spontaneous fission of {sup 252}Cf, which were performed on the WWR-M reactor at the St. Petersburg Nuclear Physics Institute, Russian Academy of Sciences, are presented. Along with obtaining the main characteristics of the instantaneous radiation from fission fragments, these studies were also aimed at gaining deeper insight into such exotic processes as the emission of break neutrons and {gamma} photons from a fissioning nucleus near the break point. These investigations were performed on different experimental setups using different analytical methods. This approach allowed us not only to find but also to reduce to minimum possible systematic effects. The yields of break neutrons were found to be about (5-7) Multiplication-Sign 10{sup -2} of the total number of neutrons per {sup 233,235}U(n, f) fission event and approximately twice as much for {sup 239}Pu(n, f) and {sup 252}Cf. The coefficient of T-odd asymmetry for {gamma} photons is in agreement with the estimate obtained on the assumption that the observed effect is mainly related to the {gamma} photons emitted by excited fragments with highly oriented angular momenta. This fact gave grounds to conclude that the desired break {gamma} photons cannot be reliably selected (within the obtained experimental accuracy) against the much larger background of {gamma} photons from fission fragments.

  8. Power equations in endurance sports.

    PubMed

    van Ingen Schenau, G J; Cavanagh, P R

    1990-01-01

    This paper attempts to clarify the formulation of power equations applicable to a variety of endurance activities. An accurate accounting of the relationship between the metabolic power input and the mechanical power output is still elusive, due to such issues as storage and recovery of strain energy and the differing energy costs of concentric and eccentric muscle actions. Nevertheless, an instantaneous approach is presented which is based upon the application of conventional Newtonian mechanics to a rigid segment model of the body, and does not contain assumptions regarding the exact nature of segmental interactions--such as energy transfer, etc. The application of the equation to running, cycling, speed skating, swimming and rowing is discussed and definitions of power, efficiency, and economy are presented.

  9. Reactivity Control Schemes for Fast Spectrum Space Nuclear Reactors

    SciTech Connect

    Craft, Aaron E.; King, Jeffrey C.

    2008-01-21

    Several different reactivity control schemes are considered for future space nuclear reactor power systems. Each of these control schemes uses a combination of boron carbide absorbers and/or beryllium oxide reflectors to achieve sufficient reactivity swing to keep the reactor subcritical during launch and to provide sufficient excess reactivity to operate the reactor over its expected 7-15 year lifetime. The size and shape of the control system directly impacts the size and mass of the space reactor's reflector and shadow shield, leading to a tradeoff between reactivity swing and total system mass. This paper presents a trade study of drum, shutter, and petal control schemes based on reactivity swing and mass effects for a representative fast-spectrum, gas-cooled reactor. For each control scheme, the dimensions and composition of the core are constant, and the reflector is sized to provide $5 of cold-clean excess reactivity with each configuration in its most reactive state. The advantages and disadvantages of each configuration are discussed, along with optimization techniques and novel geometric approaches for each scheme.

  10. Structure and Dynamics of the Instantaneous Water/Vapor Interface Revisited by Path-Integral and Ab Initio Molecular Dynamics Simulations.

    PubMed

    Kessler, Jan; Elgabarty, Hossam; Spura, Thomas; Karhan, Kristof; Partovi-Azar, Pouya; Hassanali, Ali A; Kühne, Thomas D

    2015-08-01

    The structure and dynamics of the water/vapor interface is revisited by means of path-integral and second-generation Car-Parrinello ab initio molecular dynamics simulations in conjunction with an instantaneous surface definition [Willard, A. P.; Chandler, D. J. Phys. Chem. B 2010, 114, 1954]. In agreement with previous studies, we find that one of the OH bonds of the water molecules in the topmost layer is pointing out of the water into the vapor phase, while the orientation of the underlying layer is reversed. Therebetween, an additional water layer is detected, where the molecules are aligned parallel to the instantaneous water surface.

  11. Hydrothermal reactivity of saponite.

    USGS Publications Warehouse

    Whitney, G.

    1983-01-01

    The nature and extent of the reactions of synthetic Fe-free saponite have been investigated under experimental hydrothermal conditions as a first step towards understanding saponite reactivity under relatively simple conditions. Saponite crystallizes from amorphous gel of ideal saponite composition within 7 days at 300o-550oC under P = 1 kbar. Reactions subsequent to this initial crystallization depend on reaction T and interlayer cations. Saponite is found to react hydrothermally, over a period of 200 days, at T down to 400oC, at least 150oC lower than previously reported, but showed no signs of reaction below 400oC. At 450oC, a mixture of talc/saponite and saponite/phlogopite clays forms from K-saponite via intracrystalline layer transformations, while above 450oC the initial K-saponite dissolves, with talc and phlogopite forming as discrete phases. After 200 days reactions at 400-450oC were not complete, so that given sufficient time to reach equilibrium, a lower hydrothermal stability limit for saponite is possible. Further study of the Fe-bearing saponite system will be required before experimental results can be applied to natural systems.-D.F.B.

  12. Myochrysine Solution Structure and Reactivity

    PubMed Central

    Jones, William B.; Zhao, Zheng; Dorsey, John G.; Tepperman, Katherine

    1994-01-01

    We have determined the framework structure of Myochrysine (disodium gold(I)thiomalate) in the solid state and extremely concentrated aqueous solution, previously. It consists of an open chain polymer with linear gold coordination to two thiolates from the thiomalic acid moieties which bridge between pairs of gold atoms providing an Au-S-Au angle of 95°. The question remained: was this structure relevant to the dilute solutions of drugs administered and the still lower concentrations of gold found in the bodies of patients (typically 1 ppm Au in blood and urine or 5 μM in Au). We have provided an answer to that question using extended X-ray absorption spectroscopy (EXAFS) and capillary zone electrophoresis (CZE). EXAFS studies confirm that the polymeric structure with two sulfur atoms per gold atom persists from molar concentrations down to millimolar concentrations. CZE is able to separate and detect Myochrysine at millimolar levels. More importantly, at micromolar levels Myochrysine solutions exhibit identical CZE behavior to that measured at millimolar levels. Thus, aqueous solutions of the drug remain oligomeric at concentrations commensurate with those found in patient blood and urine. The reactivity of Myochrysine with cyanide, a species especially prevalent in smoking patients, was explored using CZE. Cyanide freely replaces thiomalic acid to form [Au(CN)2]- and thiomalic acid via a mixed ligand intermediate. The overall apparent equilibrium constant (Kapp) for the reaction is 6×10-4M-1. Further reaction of [Au(CN)2]- with a large excess of L, where L is cysteine, N-acetylcysteine, or glutathione, shows that these amino acids readily replace cyanide to form [AuL2]-. These species are thus potential metabolites and could possibly be active forms of gold in vivo. That all of these species are readily separated and quantified using CZE demonstrates that capillary electrophoresis is an accessible and powerful tool to add to those used for the study of gold

  13. Airborne measurement of OH reactivity during INTEX-B

    NASA Astrophysics Data System (ADS)

    Mao, J.; Ren, X.; Brune, W. H.; Olson, J. R.; Crawford, J. H.; Fried, A.; Huey, L. G.; Cohen, R. C.; Heikes, B.; Singh, H. B.; Blake, D. R.; Sachse, G. W.; Diskin, G. S.; Hall, S. R.; Shetter, R. E.

    2009-01-01

    The measurement of OH reactivity, the inverse of the OH lifetime, provides a powerful tool to investigate atmospheric photochemistry. A new airborne OH reactivity instrument was designed and deployed for the first time on the NASA DC-8 aircraft during the second phase of Intercontinental Chemical Transport Experiment-B (INTEX-B) campaign, which was focused on the Asian pollution outflow over Pacific Ocean and was based in Hawaii and Alaska. The OH reactivity was measured by adding OH, generated by photolyzing water vapor with 185 nm UV light in a moveable wand, to the flow of ambient air in a flow tube and measuring the OH signal with laser induced fluorescence. As the wand was pulled back away from the OH detector, the OH signal decay was recorded; the slope of -Δln(signal)/Δ time was the OH reactivity. The overall absolute uncertainty at the 2σ confidence levels is about 1 s-1 at low altitudes (for decay about 6 s-1), and 0.7 s-1 at high altitudes (for decay about 2 s-1). From the median vertical profile obtained in the second phase of INTEX-B, the measured OH reactivity (4.0±1.0 s-1) is higher than the OH reactivity calculated from assuming that OH was in steady state (3.3±0.8 s-1), and even higher than the OH reactivity that was calculated from the total measurements of all OH reactants (1.6±0.4 s-1). Model calculations show that the missing OH reactivity is consistent with the over-predicted OH and under-predicted HCHO in the boundary layer and lower troposphere. The over-predicted OH and under-predicted HCHO suggest that the missing OH sinks are most likely related to some highly reactive VOCs that have HCHO as an oxidation product.

  14. Trends in Atmospheric Reactive Nitrogen for the Eastern United States

    EPA Science Inventory

    Reactive nitrogen can travel far from emission sources and impact sensitive ecosystems. From 2002-2006, policy actions have led to decreases in NOx emissions from power plants and motor vehicles. In this study, atmospheric chemical transport modeling demonstrates tha...

  15. Instantaneous Imaging Diagnostics for Measuring Particle Sizes and Spatial Distributions Over Extended Regions in Two-Phase Flows.

    NASA Astrophysics Data System (ADS)

    Hofeldt, David Larry

    Two new optimal diagnostics capable of instantaneously measuring the size and spatial distribution of many particles in two-phase flows of moderate number densities (10 ^3-10^4 per cm ^3) have been developed and characterized. They utilize a broadband laser source to illuminate a planar section of the flowfield, and commercially available, uncooled, CCD video cameras to image the scattering normal to the illuminated plane and record the spatial distribution of the particles. Individual particle image intensities and/or polarization ratios are related to particle size by comparison with Lorenz-Mie scattering theory. Simple image processing algorithms can be used to provide nearly real-time measurements of size and spatial distribution. Important advantages over existing techniques include the ability to size many particles simultaneously while retaining spatial distribution information, simplified data reduction, and the elimination of velocity bias from the measured distributions. Experimental results for monodisperse droplet streams are presented to demonstrate the particle sizing capability and identify sources of uncertainty. A detailed analysis of both random and systematic error sources is given, and suggestions for improving the accuracy of the technique are presented. The results indicate that individual particles in the size range of 10-100 mu m can be sized with an accuracy of +/- 20% using the current experimental setup based on scattered energy. Accuracies of +/-10% should be possible after implementation of suggested improvements. Measurements of the instantaneous polarization were found to be unsuitable for individual particle size determination, but could be useful for determining size distribution statistics based on a large number of images. The techniques are ideally suited for measurements of homogeneous, spherical particles immersed in a homogeneous medium, pseudo-plane wave illumination, and single particle scattering. A discussion of the

  16. Comparison of Techniques to Estimate Ammonia Emissions at Cattle Feedlots Using Time-Averaged and Instantaneous Concentration Measurements

    NASA Astrophysics Data System (ADS)

    Shonkwiler, K. B.; Ham, J. M.; Williams, C. M.

    2013-12-01

    Ammonia (NH3) that volatilizes from confined animal feeding operations (CAFOs) can form aerosols that travel long distances where such aerosols can deposit in sensitive regions, potentially causing harm to local ecosystems. However, quantifying the emissions of ammonia from CAFOs through direct measurement is very difficult and costly to perform. A system was therefore developed at Colorado State University for conditionally sampling NH3 concentrations based on weather parameters measured using inexpensive equipment. These systems use passive diffusive cartridges (Radiello, Sigma-Aldrich, St. Louis, MO, USA) that provide time-averaged concentrations representative of a two-week deployment period. The samplers are exposed by a robotic mechanism so they are only deployed when wind is from the direction of the CAFO at 1.4 m/s or greater. These concentration data, along with other weather variables measured during each sampler deployment period, can then be used in a simple inverse model (FIDES, UMR Environnement et Grandes Cultures, Thiverval-Grignon, France) to estimate emissions. There are not yet any direct comparisons of the modeled emissions derived from time-averaged concentration data to modeled emissions from more sophisticated backward Lagrangian stochastic (bLs) techniques that utilize instantaneous measurements of NH3 concentration. In the summer and autumn of 2013, a suite of robotic passive sampler systems were deployed at a 25,000-head cattle feedlot at the same time as an open-path infrared (IR) diode laser (GasFinder2, Boreal Laser Inc., Edmonton, Alberta, Canada) which continuously measured ammonia concentrations instantaneously over a 225-m path. This particular laser is utilized in agricultural settings, and in combination with a bLs model (WindTrax, Thunder Beach Scientific, Inc., Halifax, Nova Scotia, Canada), has become a common method for estimating NH3 emissions from a variety of agricultural and industrial operations. This study will first

  17. Computation and analysis of the instantaneous-discharge record for the Colorado River at Lees Ferry, Arizona : May 8, 1921, through September 30, 2000

    USGS Publications Warehouse

    Topping, David J.; Schmidt, John C.; Vierra, L.E.

    2003-01-01

    operations on a river. Following the construction and quality-control checks of the continuous record of instantaneous discharge, analyses of flow duration, sub-daily flow variability, and flood frequency were conducted on the pre- and post-dam parts of the record. These analyses indicate that although the discharge of the Colorado River varied substantially prior to the closure of Glen Canyon Dam in 1963, operation of the dam has caused changes in discharge that are more extreme than the pre-dam natural variability. Operation of the dam has eliminated flood flows and base flows, and thereby has effectively 'flattened' the annual hydrograph. Prior to closure of the dam, the discharge of the Colorado River at Lees Ferry was lower than 7,980 ft3/s half of the time. Discharges lower than about 9,000 ft3/s were important for the seasonal accumulation and storage of sand in the pre-dam river downstream from Lees Ferry. The current operating plan for Glen Canyon Dam no longer allows sustained discharges lower than 8,000 ft3/s to be released. Thus, closure of the dam has not only cut off the upstream supply of sediment, but operation of the dam has also largely eliminated discharges during which sand could be demonstrated to accumulate in the river. In addition to radically changing the hydrology of the river, operation of the dam for hydroelectric-power generation has introduced large daily fluctuations in discharge. During the pre-dam era, the median daily range in discharge was only 542 ft3/s, although daily ranges in discharge exceeding 20,000 ft3/s were observed during the summer thunderstorm season. Relative to the pre-dam period of record, dam operations have increased the daily range in discharge during all but 0.1 percent of all days. The post-dam median daily range in discharge, 8,580 ft3/s, exceeds the pre-dam median discharge of 7,980 ft3/s. Operation of the dam has also radically changed the frequency of floods on the Colorado River at Lees Ferry. The frequency of f

  18. Kinetics of reactive wetting

    SciTech Connect

    Yost, F.G.

    2000-04-14

    The importance of interfacial processes in materials joining has a long history. A significant amount of work has suggested that processes collateral to wetting can affect the extent of wetting and moderate or retard wetting rate. Even very small additions of a constituent, known to react with the substrate, cause pronounced improvement in wetting and are exploited in braze alloys, especially those used for joining to ceramics. In the following a model will be constructed for the wetting kinetics of a small droplet of metal containing a constituent that diffuses to the wetting line and chemically reacts with a flat, smooth substrate. The model is similar to that of Voitovitch et al. and Mortensen et al. but incorporates chemical reaction kinetics such that the result contains both diffusion and reaction kinetics. The model is constructed in the circular cylinder coordinate system, satisfies the diffusion equation under conditions of slow flow, and considers diffusion and reaction at the wetting line to be processes in series. This is done by solving the diffusion equation with proper initial and boundary conditions, computing the diffusive flux at the wetting line, and equating this to both the convective flux and reaction flux. This procedure is similar to equating the current flowing in components of a series circuit. The wetting rate will be computed versus time for a variety of diffusion and reaction conditions. A transition is observed from nonlinear (diffusive) to linear (reactive) behavior as the control parameters (such as the diffusion coefficient) are modified. This is in agreement with experimental observations. The adequacy of the slow flow condition, used in this type of analysis, is discussed and an amended procedure is suggested.

  19. A data processing method for determining instantaneous angular speed and acceleration of crankshaft in an aircraft engine-propeller system using a magnetic encoder

    NASA Astrophysics Data System (ADS)

    Yu, S. D.; Zhang, X.

    2010-05-01

    This paper presents a method for determining the instantaneous angular speed and instantaneous angular acceleration of the crankshaft in a reciprocating engine and propeller dynamical system from electrical pulse signals generated by a magnetic encoder. The method is based on accurate determination of the measured global mean angular speed and precise values of times when leading edges of individual magnetic teeth pass through the magnetic sensor. Under a steady-state operating condition, a discrete deviation time vs. shaft rotational angle series of uniform interval is obtained and used for accurate determination of the crankshaft speed and acceleration. The proposed method for identifying sub- and super-harmonic oscillations in the instantaneous angular speeds and accelerations is new and efficient. Experiments were carried out on a three-cylinder four-stroke Saito 450R model aircraft engine and a Solo propeller in connection with a 64-teeth Admotec KL2202 magnetic encoder and an HS-4 data acquisition system. Comparisons with an independent data processing scheme indicate that the proposed method yields noise-free instantaneous angular speeds and is superior to the finite difference based methods commonly used in the literature.

  20. Using the procedure of spectral projection for reactivity determination in physically large nuclear reactors

    SciTech Connect

    Cherezov, A. L. Schukin, N. V.; Semyonov, A. A.; Solov'yov, D. A.

    2011-12-15

    The reactivity determination methods which are based on the neutron field reconstruction procedure and the spectral-projection method are analyzed. The approximate methods of reactivity determination which can be used in practice are offered. The efficiency of the proposed methods in comparison to that of the methods applied in operation of nuclear power plants is demonstrated using computational models.