WorldWideScience

Sample records for single mobile phase

  1. Nonequilibrium phase diagram of a one-dimensional quasiperiodic system with a single-particle mobility edge

    Science.gov (United States)

    Purkayastha, Archak; Dhar, Abhishek; Kulkarni, Manas

    2017-11-01

    We investigate and map out the nonequilibrium phase diagram of a generalization of the well known Aubry-André-Harper (AAH) model. This generalized AAH (GAAH) model is known to have a single-particle mobility edge which also has an additional self-dual property akin to that of the critical point of the AAH model. By calculating the population imbalance, we get hints of a rich phase diagram. We also find a fascinating connection between single particle wave functions near the mobility edge of the GAAH model and the wave functions of the critical AAH model. By placing this model far from equilibrium with the aid of two baths, we investigate the open system transport via system size scaling of nonequilibrium steady state (NESS) current, calculated by fully exact nonequilibrium Green's function (NEGF) formalism. The critical point of the AAH model now generalizes to a `critical' line separating regions of ballistic and localized transport. Like the critical point of the AAH model, current scales subdiffusively with system size on the `critical' line (I ˜N-2 ±0.1 ). However, remarkably, the scaling exponent on this line is distinctly different from that obtained for the critical AAH model (where I ˜N-1.4 ±0.05 ). All these results can be understood from the above-mentioned connection between states near the mobility edge of the GAAH model and those of the critical AAH model. A very interesting high temperature nonequilibrium phase diagram of the GAAH model emerges from our calculations.

  2. Single-Phase PLLs

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2017-01-01

    Single-phase phase-locked loops (PLLs) are popular for the synchronization and control of single-phase gridconnected converters. They are also widely used for monitoring and diagnostic purposes in the power and energy areas. In recent years, a large number of single-phase PLLs with different stru......-PLLs). The members of each category are then described and their pros and cons are discussed. This work provides a deep insight into characteristics of different single-phase PLLs and, therefore, can be considered as a reference for researchers and engineers....

  3. Simulation of Intelligent Single Wheel Mobile Robot

    Directory of Open Access Journals (Sweden)

    Maki K. Rashid

    2008-11-01

    Full Text Available Stabilization of a single wheel mobile robot attracted researcher attentions in robotic area. However, the budget requirements for building experimental setups capable in investigating isolated parameters and implementing others encouraged the development of new simulation methods and techniques that beat such limitations. In this work we have developed a simulation platform for testing different control tactics to stabilize a single wheel mobile robot. The graphic representation of the robot, the dynamic solution, and, the control scheme are all integrated on common computer platform using Visual Basic. Simulation indicates that we can control such robot without knowing the detail of it's internal structure or dynamics behaviour just by looking at it and using manual operation tactics. Twenty five rules are extracted and implemented using Takagi-Sugeno's fuzzy controller with significant achievement in controlling robot motion during the dynamic simulation. The resulted data from the successful implementation of the fuzzy model are used to utilize and train a neurofuzzy controller using ANFIS scheme to produce further improvement in robot performance

  4. Influence of mobile dislocations on phase separation in binary alloys

    International Nuclear Information System (INIS)

    Haataja, Mikko; Leonard, Francois

    2004-01-01

    We introduce a continuum model to describe the phase separation of a binary alloy in the presence of mobile dislocations. The kinetics of the local composition and dislocation density are coupled through their elastic fields. We show both analytically and numerically that mobile dislocations modify the standard spinodal decomposition process, and lead to several regimes of growth. Depending on the dislocation mobility and observation time, the phase separation may be accelerated, decelerated, or unaffected by mobile dislocations. For any finite dislocation mobility, we show that the domain growth rate asymptotically becomes independent of the dislocation mobility, and is faster than the dislocation-free growth rate

  5. Effect of Foam on Liquid Phase Mobility in Porous Media

    NARCIS (Netherlands)

    Eftekhari, A.A.; Farajzadeh, R.

    2017-01-01

    We investigate the validity of the assumption that foam in porous media reduces the mobility of gas phase only and does not impact the liquid-phase mobility. The foam is generated by simultaneous injection of nitrogen gas and a surfactant solution into sandstone cores and its strength is varied by

  6. Preparation of single phase molybdenum boride

    International Nuclear Information System (INIS)

    Camurlu, Hasan Erdem

    2011-01-01

    Highlights: → Formation of Mo and a mixture of molybdenum boride phases take place in preparation of molybdenum borides. → It is intricate to prepare single phase molybdenum borides. → Formation of single phase MoB from MoO 3 + B 2 O 3 + Mg mixtures has not been reported previously. → Single phase MoB was successfully prepared through a combination of mechanochemical synthesis and annealing process. - Abstract: The formation of MoB through volume combustion synthesis (VCS), and through mechanochemical synthesis (MCS) followed by annealing has been investigated. MoO 3 , B 2 O 3 and Mg were used as reactants while MgO and NaCl were introduced as diluents. Products were leached in dilute HCl solution and were subjected to X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) examinations. Mo was the major phase component in the VCS products under all the experimental conditions. Mo 2 B, MoB, MoB 2 and Mo 2 B 5 were found as minor phases. Products of MCS contained a mixture of Mo 2 B, MoB, MoB 2 and Mo. After annealing the MCS product at 1400 deg. C for 3 h, single phase α-MoB was obtained.

  7. Effect of Foam on Liquid Phase Mobility in Porous Media

    DEFF Research Database (Denmark)

    Eftekhari, Ali Akbar; Farajzadeh, R.

    2017-01-01

    We investigate the validity of the assumption that foam in porous media reduces the mobility of gas phase only and does not impact the liquid-phase mobility. The foam is generated by simultaneous injection of nitrogen gas and a surfactant solution into sandstone cores and its strength is varied...... by changing surfactant type and concentration. We find, indeed, that the effect of foam on liquid-phase mobility is not pronounced and can be ignored. Our new experimental results and analyses resolve apparent discrepancies in the literature. Previously, some researchers erroneously applied relative...

  8. MOIDSS?- Mobile Online Intelligent Decision Support System, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — GRID has had a successfully completed Phase I 'Mobile Online Intelligent Decision Support System' (MOIDSS). The system developed into a total solution that supports...

  9. Single phase induction motor with starting performance

    Energy Technology Data Exchange (ETDEWEB)

    Popescu, M.; Demeter, E. [Research Institute for Electrical Machines, ICPE-ME, Bucharest (Romania); Navrapescu, V. [University `Politehnica` Bucharest, Electrical Engineering Faculty Splaiul Independentei, Bucharest (Romania)

    1997-12-31

    The paper presents problems related to a special type of single phase induction motor. The main novelty consists in the use of a conducting (aluminium casted) shell distributed on the periferic region of the rotor. As a result the starting performance, as well as the rated ones, is much improved in comparison with the conventional construction. (orig.) 4 refs.

  10. Control of Single-Stage Single-Phase PV inverter

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Teodorescu, Remus; Blaabjerg, Frede

    2005-01-01

    In this paper the issue of control strategies for single-stage photovoltaic (PV) inverter is addressed. Two different current controllers have been implemented and an experimental comparison between them has been made. A complete control structure for the single-phase PV system is also presented......-forward; - and the grid current controller implemented in two different ways, using the classical proportional integral (PI) and the novel proportional resonant (PR) controllers. The control strategy was tested experimentally on 1.5 kW PV inverter....

  11. Project inspection using mobile technology - phase II : assessing the impacts of mobile technology on project inspection.

    Science.gov (United States)

    2015-01-01

    As mobile technology becomes widely available and affordable, transportation agencies can use this : technology to streamline operations involved within project inspection. This research, conducted in two : phases, identified opportunities for proces...

  12. The Mobile Phase Motion in Ascending Micellar Thin-Layer Chromatography with Normal-Phase Plates

    NARCIS (Netherlands)

    Boichenko, Alexander P.; Makhno, Iryna V.; Renkevich, Anton Yu.; Loginova, Lidia P.

    2011-01-01

    The physical chemical characteristics (surface tension and viscosity) of micellar mobile phases based on the cationic surfactant cetylpiridinium chloride and additives of alcohols (ethanol, 1-propanol, 1-butanol, 1-pentanol) have been obtained in this work. The effect of mobile phase properties on

  13. Efficient electronic entanglement concentration assisted by single mobile electrons

    International Nuclear Information System (INIS)

    Sheng Yu-Bo; Zhou Lan

    2013-01-01

    We present an efficient entanglement concentration protocol (ECP) for mobile electrons with charge detection. This protocol is quite different from other ECPs for one can obtain a maximally entangled pair from a pair of less-entangled state and a single mobile electron with a certain probability. With the help of charge detection, it can be repeated to reach a higher success probability. It also does not need to know the coefficient of the original less-entangled states. All these advantages may make this protocol useful in current distributed quantum information processing

  14. Load compensation for single phase system using series active filter

    African Journals Online (AJOL)

    user

    Keywords: Active power filter (APF), current source type of harmonic load ... Single phase active filters could attract less attention than three phase due to its low ..... Generalised single-phase p-q theory for active power filtering: simulation and.

  15. Unified pH values of liquid chromatography mobile phases.

    Science.gov (United States)

    Suu, Agnes; Jalukse, Lauri; Liigand, Jaanus; Kruve, Anneli; Himmel, Daniel; Krossing, Ingo; Rosés, Martí; Leito, Ivo

    2015-03-03

    This work introduces a conceptually new approach of measuring pH of mixed-solvent liquid chromatography (LC) mobile phases. Mobile phase pH is very important in LC, but its correct measurement is not straightforward, and all commonly used approaches have deficiencies. The new approach is based on the recently introduced unified pH (pH(abs)) scale, which enables direct comparison of acidities of solutions made in different solvents based on chemical potential of the proton in the solutions. This work represents the first experimental realization of the pH(abs) concept using differential potentiometric measurement for comparison of the chemical potentials of the proton in different solutions (connected by a salt bridge), together with earlier published reference points for obtaining the pH(abs) values (referenced to the gas phase) or pH(abs)(H₂O) values (referenced to the aqueous solution). The liquid junction potentials were estimated in the framework of Izutsu's three-component method. pH(abs) values for a number of common LC and LC-MS mobile phases have been determined. The pH(abs) scale enables for the first time direct comparison of acidities of any LC mobile phases, with different organic additives, different buffer components, etc. A possible experimental protocol of putting this new approach into chromatographic practice has been envisaged and its applicability tested. It has been demonstrated that the ionization behavior of bases (cationic acids) in the mobile phases can be better predicted by using the pH(abs)(H₂O) values and aqueous pKa values than by using the alternative means of expressing mobile phase acidity. Description of the ionization behavior of acids on the basis of pH(abs)(H₂O) values is possible if the change of their pKa values with solvent composition change is taken into account.

  16. Single-Receiver GPS Phase Bias Resolution

    Science.gov (United States)

    Bertiger, William I.; Haines, Bruce J.; Weiss, Jan P.; Harvey, Nathaniel E.

    2010-01-01

    Existing software has been modified to yield the benefits of integer fixed double-differenced GPS-phased ambiguities when processing data from a single GPS receiver with no access to any other GPS receiver data. When the double-differenced combination of phase biases can be fixed reliably, a significant improvement in solution accuracy is obtained. This innovation uses a large global set of GPS receivers (40 to 80 receivers) to solve for the GPS satellite orbits and clocks (along with any other parameters). In this process, integer ambiguities are fixed and information on the ambiguity constraints is saved. For each GPS transmitter/receiver pair, the process saves the arc start and stop times, the wide-lane average value for the arc, the standard deviation of the wide lane, and the dual-frequency phase bias after bias fixing for the arc. The second step of the process uses the orbit and clock information, the bias information from the global solution, and only data from the single receiver to resolve double-differenced phase combinations. It is called "resolved" instead of "fixed" because constraints are introduced into the problem with a finite data weight to better account for possible errors. A receiver in orbit has much shorter continuous passes of data than a receiver fixed to the Earth. The method has parameters to account for this. In particular, differences in drifting wide-lane values must be handled differently. The first step of the process is automated, using two JPL software sets, Longarc and Gipsy-Oasis. The resulting orbit/clock and bias information files are posted on anonymous ftp for use by any licensed Gipsy-Oasis user. The second step is implemented in the Gipsy-Oasis executable, gd2p.pl, which automates the entire process, including fetching the information from anonymous ftp

  17. Intrinsic Charge Carrier Mobility in Single-Layer Black Phosphorus.

    Science.gov (United States)

    Rudenko, A N; Brener, S; Katsnelson, M I

    2016-06-17

    We present a theory for single- and two-phonon charge carrier scattering in anisotropic two-dimensional semiconductors applied to single-layer black phosphorus (BP). We show that in contrast to graphene, where two-phonon processes due to the scattering by flexural phonons dominate at any practically relevant temperatures and are independent of the carrier concentration n, two-phonon scattering in BP is less important and can be considered negligible at n≳10^{13}  cm^{-2}. At smaller n, however, phonons enter in the essentially anharmonic regime. Compared to the hole mobility, which does not exhibit strong anisotropy between the principal directions of BP (μ_{xx}/μ_{yy}∼1.4 at n=10^{13} cm^{-2} and T=300  K), the electron mobility is found to be significantly more anisotropic (μ_{xx}/μ_{yy}∼6.2). Absolute values of μ_{xx} do not exceed 250 (700)  cm^{2} V^{-1} s^{-1} for holes (electrons), which can be considered as an upper limit for the mobility in BP at room temperature.

  18. Domain switching in single-phase multiferroics

    Science.gov (United States)

    Jia, Tingting; Cheng, Zhenxiang; Zhao, Hongyang; Kimura, Hideo

    2018-06-01

    Multiferroics are a time-honoured research subject by reason for their tremendous application potential in the information industry, such as in multi-state information storage devices and new types of sensors. An outburst of studies on multiferroicity has been witnessed in the 21st century, although this field has a long research history since the 19th century. Multiferroicity has now become one of the hottest research topics in condensed matter physics and materials science. Numerous efforts have been made to investigate the cross-coupling phenomena among ferroic orders such as ferroelectricity, (anti-)ferromagnetism, and ferroelasticity, especially the coupling between electric and magnetic orderings that would account for the magnetoelectric (ME) effect in multiferroic materials. The magnetoelectric properties and coupling behavior of single phase multiferroics are dominated by their domain structures. It was also noted that, however, the multiferroic materials exhibit very complicated domain structures. Studies on domain structure characterization and domain switching are a crucial step in the exploration of approaches to the control and manipulation of magnetic (electric) properties using an electric (magnetic) field or other means. In this review, following a concise outline of our current basic knowledge on the magnetoelectric (ME) effect, we summarize some important research activities on domain switching in single-phase multiferroic materials in the form of single crystals and thin films, especially domain switching behavior involving strain and the related physics in the last decade. We also introduce recent developments in characterization techniques for domain structures of ferroelectric or multiferroic materials, which have significantly advanced our understanding of domain switching dynamics and interactions. The effects of a series of issues such as electric field, magnetic field, and stress effects on domain switching are been discussed as well. It

  19. Instability of single-phase natural circulation

    International Nuclear Information System (INIS)

    Xie Heng; Zhang Jinling; Jia Dounan

    1997-01-01

    The author has investigated the instability of single-phase flows in natural circulation loops. The momentum equation and energy equation are made dimensionless according to some definitions, and some important dimensionless parameters are gotten. The authors decomposed the mean mass flowrate and temperature into a steady solution and a small disturbance equations. Through solving the disturbance equations, the authors get the neutral stability curves. The authors have studied the effect of the two parameters which represent the ratio of buoyancy force to the friction loss in the loop on the stability of loops. The authors also have studied the effect of the difference of height between the center of heat source and the heat sink on the stability

  20. 77 FR 9655 - Mobility Fund Phase I Auction Updated List of Potentially Eligible Census Blocks

    Science.gov (United States)

    2012-02-17

    ... FEDERAL COMMUNICATIONS COMMISSION [AU Docket No. 12-25; DA 12-187] Mobility Fund Phase I Auction.... DATES: Pursuant to the Auction 901 (Mobility Fund Phase I) Comment Public Notice, 77 FR 7152, February... 9, 2012. ADDRESSES: Pursuant to the Auction 901 (Mobility Fund Phase I) Comment Public Notice, 77 FR...

  1. Molecular Mobility in Phase Segregated Bottlebrush Block Copolymer Melts

    Science.gov (United States)

    Yavitt, Benjamin; Gai, Yue; Song, Dongpo; Winter, H. Henning; Watkins, James

    We investigate the linear viscoelastic behavior of poly(styrene)-block-poly(ethylene oxide) (PS-b-PEO) brush block copolymer (BBCP) materials over a range of vol. fractions and with side chain lengths below the entanglement molecular weights. The high chain mobility of the brush architecture results in rapid micro-phase segregation of the brush copolymer segments, which occurs during thermal annealing at mild temperatures. Master curves of the dynamic moduli were obtained by time-temperature superposition. The reduced degree of chain entanglements leads to a unique liquid-like rheology similar to that of bottlebrush homopolymers, even in the phase segregated state. We also explore the alignment of phase segregated domains at exceptionally low strain amplitudes (γ = 0.01) and mild processing temperatures using small angle X-ray scattering (SAXS). Domain orientation occurred readily at strains within the linear viscoelastic regime without noticeable effect on the moduli. This interplay of high molecular mobility and rapid phase segregation that are exhibited simultaneously in BBCPs is in contrast to the behavior of conventional linear block copolymer (LBCP) analogs and opens up new possibilities for processing BBCP materials for a wide range of nanotechnology applications. NSF Center for Hierarchical Manufacturing at the University of Massachusetts, Amherst (CMMI-1025020).

  2. Single-Image Distance Measurement by a Smart Mobile Device.

    Science.gov (United States)

    Chen, Shangwen; Fang, Xianyong; Shen, Jianbing; Wang, Linbo; Shao, Ling

    2017-12-01

    Existing distance measurement methods either require multiple images and special photographing poses or only measure the height with a special view configuration. We propose a novel image-based method that can measure various types of distance from single image captured by a smart mobile device. The embedded accelerometer is used to determine the view orientation of the device. Consequently, pixels can be back-projected to the ground, thanks to the efficient calibration method using two known distances. Then the distance in pixel is transformed to a real distance in centimeter with a linear model parameterized by the magnification ratio. Various types of distance specified in the image can be computed accordingly. Experimental results demonstrate the effectiveness of the proposed method.

  3. Considerations of digital phase modulation for narrowband satellite mobile communication

    Science.gov (United States)

    Grythe, Knut

    1990-01-01

    The Inmarsat-M system for mobile satellite communication is specified as a frequency division multiple access (FDMA) system, applying Offset Quadrature Phase Shift Keying (QPSK) for transmitting 8 kbit/sec in 10 kHz user channel bandwidth. We consider Digital Phase Modulation (DPM) as an alternative modulation format for INMARSAT-M. DPM is similar to Continuous Phase Modulation (CPM) except that DPM has a finite memory in the premodular filter with a continuous varying modulation index. It is shown that DPM with 64 states in the VA obtains a lower bit error rate (BER). Results for a 5 kHz system, with the same 8 kbit/sec transmitted bitstream, is also presented.

  4. Ammonium fluoride as a mobile phase additive in aqueous normal phase chromatography.

    Science.gov (United States)

    Pesek, Joseph J; Matyska, Maria T

    2015-07-03

    The use of ammonium fluoride as a mobile phase additive in aqueous normal phase chromatography with silica hydride-based stationary phases and mass spectrometry detection is evaluated. Retention times, peak shape, efficiency and peak intensity are compared to the more standard additives formic acid and ammonium formate. The test solutes were NAD, 3-hydroxyglutaric acid, α-ketoglutaric acid, p-aminohippuric acid, AMP, ATP, aconitic acid, threonine, N-acetyl carnitine, and 3-methyladipic acid. The column parameters are assessed in both the positive and negative ion detection modes. Ammonium fluoride is potentially an aggressive mobile phase additive that could have detrimental effects on column lifetime. Column reproducibility is measured and the effects of switching between different additives are also tested. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Unravelling the effects of mobile phase additives in supercritical fluid chromatography. Part I: Polarity and acidity of the mobile phase.

    Science.gov (United States)

    West, Caroline; Melin, Jodie; Ansouri, Hassna; Mengue Metogo, Maïly

    2017-04-07

    The mobile phases employed in current supercritical fluid chromatography (SFC) are usually composed of a mixture of pressurized carbon dioxide and a co-solvent. The co-solvent is most often an alcohol and may contain a third component in small proportions, called an additive (acid, base or salt). The polarity of such mobile phase compositions is here re-evaluated with a solvatochromic dye (Nile Red), particularly to assess the contribution of additives. It appears that additives, when employed in usual concentration range (0.1% or 20mM) do not modify the polarity in the immediate environment of the probe. In addition, the combination of carbon dioxide and an alcohol is known to form alkoxylcarbonic acid, supposedly conferring some acidic character to SFC mobile phases. Direct measurements of the apparent pH are impossible, but colour indicators of pH can be used to define the range of apparent pH provided by carbon dioxide-alcohol mixtures, with or without additives. Five colour indicators (Thymol Blue, Bromocresol Green, Methyl Red, Bromocresol Purple, and Bromothymol Blue) were selected to provide a wide range of aqueous pK a values (from 1.7 to 8.9). UV-vis absorption spectra measured in liquid phases of controlled pH were compared to those measured with a diode-array detector employed in SFC, with the help of chemometric methods. Based on these observations, it is concluded that the apparent pH range in carbon dioxide-methanol mobile phases is close to 5. Increasing the proportion of methanol (in the course of a gradient elution for instance) causes decreasing apparent pH. Strong acids can further decrease the apparent pH below 1.7; strong bases have little influence on the apparent pH, probably because, in this range of concentrations, they are titrated by alkoxylcarbonic acid or form ion pairs with alkoxycarbonate. However, bases and salts could stabilize the acidity in the course of gradient runs. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. 77 FR 38803 - Mobility Fund Phase I Auction Updated Data For Auction 901

    Science.gov (United States)

    2012-06-29

    ... FEDERAL COMMUNICATIONS COMMISSION [AU Docket No. 12-25; DA 12-990] Mobility Fund Phase I Auction... files of census blocks eligible for the Mobility Fund Phase I support to be offered in Auction 901... 32092, May 31, 2012, the Bureaus described how they identified census blocks eligible for the Mobility...

  7. Single-superfield helical-phase inflation

    Energy Technology Data Exchange (ETDEWEB)

    Ketov, Sergei V., E-mail: ketov@tmu.ac.jp [Department of Physics, Tokyo Metropolitan University, Minami-ohsawa 1-1, Hachioji-shi, Tokyo 192-0397 (Japan); Kavli Institute for the Physics and Mathematics of the Universe (IPMU), The University of Tokyo, Chiba 277-8568 (Japan); Institute of Physics and Technology, Tomsk Polytechnic University, 30 Lenin Ave., Tomsk 634050 (Russian Federation); Terada, Takahiro, E-mail: takahiro@hep-th.phys.s.u-tokyo.ac.jp [Department of Physics, The University of Tokyo, Tokyo 113-0033 (Japan); Deutsches Elektronen-Synchrotron (DESY), 22607 Hamburg (Germany)

    2016-01-10

    Large-field inflation in supergravity requires the approximate global symmetry needed to protect flatness of the scalar potential. In helical-phase inflation, the U(1) symmetry of the Kähler potential is assumed, the phase part of the complex scalar of a chiral superfield plays the role of inflaton, and the radial part is strongly stabilized. The original model of helical phase inflation, proposed by Li, Li and Nanopoulos (LLN), employs an extra (stabilizer) superfield. We propose a more economical new class of the helical phase inflationary models without a stabilizer superfield. As the specific examples, the quadratic, the natural, and the Starobinsky-type inflationary models are studied in our approach.

  8. Current Harmonics from Single-Phase Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2016-01-01

    Environmental conditions and operational modes may significantly impact the distortion level of the injected current from single-phase grid-connected inverter systems, such as photovoltaic (PV) inverters, which may operate in cloudy days with a maximum power point tracking, in a non-unity power...... factor, or in the low voltage ride through mode with reactive current injection. In this paper, the mechanism of the harmonic current injection from grid-connected single-phase inverter systems is thus explored, and the analysis is conducted on single-phase PV systems. In particular, the analysis...... is focused on the impacts of the power factor and the feed-in grid current level on the quality of the feed-in grid current from single-phase inverters. As a consequence, an internal model principle based high performance current control solution is tailor-made and developed for single-phase grid-connected...

  9. Unexpectedly normal phase behavior of single homopolymer chains

    International Nuclear Information System (INIS)

    Paul, W.; Strauch, T.; Rampf, F.; Binder, K.

    2007-01-01

    Employing Monte Carlo simulations, we show that the topology of the phase diagram of a single flexible homopolymer chain changes in dependence on the range of an attractive square well interaction between the monomers. For a range of attraction larger than a critical value, the equilibrium phase diagram of the single polymer chain and the corresponding polymer solution phase diagram exhibit vapor (swollen coil, dilute solution), liquid (collapsed globule, dense solution), and solid phases. Otherwise, the liquid-vapor transition vanishes from the equilibrium phase diagram for both the single chain and the polymer solution. This change in topology of the phase diagram resembles the behavior known for colloidal dispersions. The interplay of enthalpy and conformational entropy in the polymer case thus can lead to the same topology of phase diagrams as the interplay of enthalpy and translational entropy in simple liquids

  10. High pH mobile phase effects on silica-based reversed-phase high-performance liquid chromatographic columns

    NARCIS (Netherlands)

    Kirkland, J.J.; Straten, van M.A.; Claessens, H.A.

    1995-01-01

    Aqueous mobile phases above pH 8 often cause premature column failure, limiting the utility of silica-based columns for applications requiring high pH. Previous studies suggest that covalently bound silane ligands are hydrolyzed and removed by high-pH mobile phases. However, we found that the

  11. Project inspection using mobile technology - phase I : an investigation into existing business processes and areas for improvement using mobile technology.

    Science.gov (United States)

    2013-08-01

    As mobile technology becomes widely available and affordable, transportation agencies can use this technology to : streamline operations involved within project inspection. This research, conducted in two phases, identified : opportunities for proces...

  12. A Novel Single Phase Hybrid Switched Reluctance Motor Drive System

    DEFF Research Database (Denmark)

    Liang, Jianing; Xu, Guoqing; Jian, Linni

    2011-01-01

    In this paper, a novel single phase hybrid switched reluctance motor(SRM) drive system is proposed. It integrated a single phase hybrid SRM and a novel single phase boost converter. This motor can reduce the number of phase switch. And the permanent magnet which is used in the motor can improve...... the performance and efficiency of SR motor. However, the inherent characteristic of this motor is that the negative torque is very sensitive with the excitation current near the turn-on angle. The slow excitation current limits the torque generation region and reduces the average torque. Therefore, a novel single...... phase boost converter is applied to improve the performance of this motor. It is easy to generate a double dclink voltage and dc-link voltage and switch both of them. The voltage of boost capacitor is self balance, so the protective circuit is not need to consider. The fast excitation mode helps hybrid...

  13. Dissemination of Pathogens by Mobile Phones in a Single Hospital

    Directory of Open Access Journals (Sweden)

    Michael B Canales, DPM, FACFAS

    2017-10-01

    Full Text Available Background: Superficial wound complications are among the most prevalent problems associated with any surgical procedures.  Infection rates of the primary hip and knee joint arthroplasty have been reduced with modern aseptic techniques but this rate may reach 20% in some revision procedures.  Mobile phones are frequently used in the hospital and operating room settings, regardless of their microbial load.    This study aimed to: 1 determine the level of bacterial contamination of mobile phones from resident physicians at Saint Vincent Charity Medical Center (SVCMC in Cleveland, Ohio; 2 determine the effectiveness of quaternary ammonium compound (QAC wipes; and 3 heighten awareness of potential dissemination of pathogens by mobile phones in the hospital setting. Materials & Methods: A total of fifty mobile phones were randomly sampled from podiatric surgical resident physicians and internal medicine resident physicians at SVCMC. For each mobile phone, a swab was collected from the touch screen prior to use of QAC wipes and following use of QAC wipes. Results: The results demonstrated that 82% (41/50 of mobile phone touch screens possessed polymicrobial organisms and 30% (15/50 of mobile phones possessed pathogenic organisms.  The vast majority of residents, 98% (49/50 used their phones within the hospital and 37% (18/49 used their phones inside patients’ room. Most of the residents, 86% (43/50, did not clean their phones on a daily basis and of the residents who did, a majority of them, 71% (5/7 used either dry wipes or alcohol wipes. Discussion: Sanitizing mobile phones with QAC disposable wipes was shown to be an effective infection control intervention as mobile phone touch screens showed no growth after two minutes of sanitization.  QAC could potentially decrease the transmission of microorganisms that cause diseases and reduce the risk of cross contamination infections from mobile phones.

  14. Influence of temperature upon dislocation mobility and elastic limit of single crystal HgI2

    International Nuclear Information System (INIS)

    Milstein, F.; Farber, B.; Kim, K.; van den Berg, L.; Schnepple, W.

    1982-01-01

    The practical importance of studying mechanical properties and dislocation structure of HgI 2 is reviewed briefly. Specifically, the performance of single crystal HgI 2 radiation detectors is evidently sensitive to crystalline imperfections; the dislocation structure, in turn, can be altered during detector fabrication, depending upon the mechanical properties of the crystal and the stresses to which the crystal is subjected. The influence of temperature upon dislocation mobility and plasticity in vapor-grown crystals of mercuric iodide is examined. Dislocation mobiity is determined by measuring the lengths of the longest arms of dislocation etch pit rosettes on (001) surfaces following microhardness indentation and chemical etch. Measurements were made in the range from room temperature to the phase transition temperature of 127 0 C. Dislocation mobility was found to be an increasing function of temperature, with the effect accelerating as the phase transition is approached. Increasing temperature was also found to lower the critical resolved shear stress for plastic deformation on slip on (001) planes. In these contexts, the vapor-grown crystals are clearly softer at their elevated growth temperatures. The results are discussed in terms of a dislocation model involving soft and hard glide dislocations

  15. mPano: cloud-based mobile panorama view from single picture

    Science.gov (United States)

    Li, Hongzhi; Zhu, Wenwu

    2013-09-01

    Panorama view provides people an informative and natural user experience to represent the whole scene. The advances on mobile augmented reality, mobile-cloud computing, and mobile internet can enable panorama view on mobile phone with new functionalities, such as anytime anywhere query where a landmark picture is and what the whole scene looks like. To generate and explore panorama view on mobile devices faces significant challenges due to the limitations of computing capacity, battery life, and memory size of mobile phones, as well as the bandwidth of mobile Internet connection. To address the challenges, this paper presents a novel cloud-based mobile panorama view system that can generate and view panorama-view on mobile devices from a single picture, namely "Pano". In our system, first, we propose a novel iterative multi-modal image retrieval (IMIR) approach to get spatially adjacent images using both tag and content information from the single picture. Second, we propose a cloud-based parallel server synthing approach to generate panorama view in cloud, against today's local-client synthing approach that is almost impossible for mobile phones. Third, we propose predictive-cache solution to reduce latency of image delivery from cloud server to the mobile client. We have built a real mobile panorama view system and perform experiments. The experimental results demonstrated the effectiveness of our system and the proposed key component technologies, especially for landmark images.

  16. Scheduling a Single Mobile Robot Incorporated into Production Environment

    DEFF Research Database (Denmark)

    Dang, Vinh Quang; Nielsen, Izabela Ewa; Steger-Jensen, Kenn

    2013-01-01

    to the challenges of issues such as energy conservation and pollution preventions. Facing the central tension between manufacturing and environmental drivers is difficult, but critical to develop new technologies, particularly mobile robots, that can be incorporated into production to achieve holistic solutions....... This chapter deals with the problem of finding optimal operating sequence in a manufacturing cell of a mobile robot with manipulation arm that feeds materials to feeders. The “Bartender Concept” is discussed to show the cooperation between the mobile robot and industrial environment. The performance criterion...

  17. Robust balancing and position control of a single spherical wheeled mobile platform

    OpenAIRE

    Yavuz, Fırat; Yavuz, Firat; Ünel, Mustafa; Unel, Mustafa

    2016-01-01

    Self-balancing mobile platforms with single spherical wheel, generally called ballbots, are suitable example of underactuated systems. Balancing control of a ballbot platform, which aims to maintain the upright orientation by rejecting external disturbances, is important during station keeping or trajectory tracking. In this paper, acceleration based balancing and position control of a single spherical wheeled mobile platform that has three single-row omniwheel drive m...

  18. High Energy Single Frequency Resonant Amplifier, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase I project proposes a single frequency high energy resonant amplifier for remote sensing. Current state-of-art technologies can not provide all...

  19. LENA Conversion Foils Using Single-Layer Graphene, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Our key innovation will be the use of single-layer graphene as LENA conversion foils, with appropriate microgrids and nanogrids to support the foils. Phase I...

  20. Non Invasive Instrumentation For Single Event Effects (NIISEE), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — On this Phase 1 project, Adventium will identify and address key hurdles to achieve Radiation Hardening by Software (RHS) for Single Event Effects (SEEs) for modern...

  1. Improvement of Torque Production in Single-Phase Induction Motors

    African Journals Online (AJOL)

    OLUWASOGO

    PID controller. Simulation results show the starting torque of the motor increased by 75% under the developed drive .... The model equations of the capacitor-run single phase induction .... process using the MATLAB pidtool command (Control.

  2. Load compensation for single phase system using series active filter ...

    African Journals Online (AJOL)

    Load compensation for single phase system using series active filter. ... KK Mishra, R Gupta ... load varies from time to time, the non linear load ranging from voltage source type harmonic load (VSHL) dominant to current source type harmonic ...

  3. Dynamics Assessment of Advanced Single-Phase PLL Structures

    DEFF Research Database (Denmark)

    Golestan, Saeed; Monfarad, Mohammad; Freijedo, Francisco D.

    2013-01-01

    Recently, several advanced phase locked loop (PLL) techniques have been proposed for single-phase applications. Among these, the Park-PLL, and the second order generalized integrator (SOGI) based PLL are very attractive, owing to their simple digital implementation, low computational burden...

  4. Comparative Study of Phase Transformation in Single-Crystal Germanium during Single and Cyclic Nanoindentation

    Directory of Open Access Journals (Sweden)

    Koji Kosai

    2017-11-01

    Full Text Available Single-crystal germanium is a semiconductor material which shows complicated phase transformation under high pressure. In this study, new insight into the phase transformation of diamond-cubic germanium (dc-Ge was attempted by controlled cyclic nanoindentation combined with Raman spectroscopic analysis. Phase transformation from dc-Ge to rhombohedral phase (r8-Ge was experimentally confirmed for both single and cyclic nanoindentation under high loading/unloading rates. However, compared to single indentation, double cyclic indentation with a low holding load between the cycles caused more frequent phase transformation events. Double cyclic indentation caused more stress in Ge than single indentation and increased the possibility of phase transformation. With increase in the holding load, the number of phase transformation events decreased and finally became less than that under single indentation. This phenomenon was possibly caused by defect nucleation and shear accumulation during the holding process, which were promoted by a high holding load. The defect nucleation suppressed the phase transformation from dc-Ge to r8-Ge, and shear accumulation led to another phase transformation pathway, respectively. A high holding load promoted these two phenomena, and thus decreased the possibility of phase transformation from dc-Ge to r8-Ge.

  5. A simple output voltage control scheme for single phase wavelet ...

    African Journals Online (AJOL)

    DR OKE

    of the wavelet modulated (WM) scheme is that a single synthesis function, derived ... a single-phase H-bridge voltage-source (VS) inverter using MATLAB simulations. ... reconstruction process has been suggested to device a new class of ...

  6. Unconventional phase transitions in a constrained single polymer chain

    International Nuclear Information System (INIS)

    Klushin, L I; Skvortsov, A M

    2011-01-01

    Phase transitions were recognized among the most fascinating phenomena in physics. Exactly solved models are especially important in the theory of phase transitions. A number of exactly solved models of phase transitions in a single polymer chain are discussed in this review. These are three models demonstrating the second order phase transitions with some unusual features: two-dimensional model of β-structure formation, the model of coil–globule transition and adsorption of a polymer chain grafted on the solid surface. We also discuss models with first order phase transitions in a single macromolecule which admit not only exact analytical solutions for the partition function with explicit finite-size effects but also the non-equilibrium free energy as a function of the order parameter (Landau function) in closed analytical form. One of them is a model of mechanical desorption of a macromolecule, which demonstrates an unusual first order phase transition with phase coexistence within a single chain. Features of first and second order transitions become mixed here due to phase coexistence which is not accompanied by additional interfacial free energy. Apart from that, there exist several single-chain models belonging to the same class (adsorption of a polymer chain tethered near the solid surface or liquid–liquid interface, and escape transition upon compressing a polymer between small pistons) that represent examples of a highly unconventional first order phase transition with several inter-related unusual features: no simultaneous phase coexistence, and hence no phase boundary, non-concave thermodynamic potential and non-equivalence of conjugate ensembles. An analysis of complex zeros of partition functions upon approaching the thermodynamic limit is presented for models with and without phase coexistence. (topical review)

  7. Determination of gas phase protein ion densities via ion mobility analysis with charge reduction.

    Science.gov (United States)

    Maisser, Anne; Premnath, Vinay; Ghosh, Abhimanyu; Nguyen, Tuan Anh; Attoui, Michel; Hogan, Christopher J

    2011-12-28

    We use a charge reduction electrospray (ESI) source and subsequent ion mobility analysis with a differential mobility analyzer (DMA, with detection via both a Faraday cage electrometer and a condensation particle counter) to infer the densities of single and multiprotein ions of cytochrome C, lysozyme, myoglobin, ovalbumin, and bovine serum albumin produced from non-denaturing (20 mM aqueous ammonium acetate) and denaturing (1 : 49.5 : 49.5, formic acid : methanol : water) ESI. Charge reduction is achieved through use of a Po-210 radioactive source, which generates roughly equal concentrations of positive and negative ions. Ions produced by the source collide with and reduce the charge on ESI generated drops, preventing Coulombic fissions, and unlike typical protein ESI, leading to gas-phase protein ions with +1 to +3 excess charges. Therefore, charge reduction serves to effectively mitigate any role that Coulombic stretching may play on the structure of the gas phase ions. Density inference is made via determination of the mobility diameter, and correspondingly the spherical equivalent protein volume. Through this approach it is found that for both non-denaturing and denaturing ESI-generated ions, gas-phase protein ions are relatively compact, with average densities of 0.97 g cm(-3) and 0.86 g cm(-3), respectively. Ions from non-denaturing ESI are found to be slightly more compact than predicted from the protein crystal structures, suggesting that low charge state protein ions in the gas phase are slightly denser than their solution conformations. While a slight difference is detected between the ions produced with non-denaturing and denaturing ESI, the denatured ions are found to be much more dense than those examined previously by drift tube mobility analysis, in which charge reduction was not employed. This indicates that Coulombic stretching is typically what leads to non-compact ions in the gas-phase, and suggests that for gas phase

  8. Comparison of liquid and supercritical fluid chromatography mobile phases for enantioselective separations on polysaccharide stationary phases.

    Science.gov (United States)

    Khater, Syame; Lozac'h, Marie-Anne; Adam, Isabelle; Francotte, Eric; West, Caroline

    2016-10-07

    Analysis and production of enantiomerically pure compounds is a major topic of interest when active pharmaceutical ingredients are concerned. Enantioselective chromatography has become a favourite both at the analytical and preparative scales. High-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) are dominating the scene and are often seen as complementary techniques. Nowadays, for economic and ecologic reasons, SFC may be preferred over normal-phase HPLC (NPLC) as it allows significant reductions in solvent consumption. However, the transfer of NPLC methods to SFC is not always straightforward. In this study, we compare the retention of achiral molecules and separation of enantiomers under supercritical fluid (carbon dioxide with ethanol or isopropanol) and liquid normal-phase (heptane with ethanol or isopropanol) elution modes with polysaccharide stationary phases in order to explore the differences between the retention and enantioseparation properties between the two modes. Chemometric methods (namely quantitative structure-retention relationships and discriminant analysis) are employed to compare the results obtained on a large set of analytes (171 achiral probes and 97 racemates) and gain some understanding on the retention and separation mechanisms. The results indicate that, contrary to popular belief, carbon dioxide - solvent SFC mobile phases are often weaker eluents than liquid mobile phases. It appears that SFC and NPLC elution modes provide different retention mechanisms. While some enantioseparations are unaffected, facilitating the transfer between the two elution modes, other enantioseparations may be drastically different due to different types and strength of interactions contributing to enantioselectivity. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Single-phase DECT with VNCT compared with three-phase CTU in patients with haematuria

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jung Jae; Park, Byung Kwan; Kim, Chan Kyo [Sungkyunkwan University School of Medicine, Department of Radiology, Samsung Medical Center, Seoul (Korea, Republic of)

    2016-10-15

    To retrospectively evaluate the diagnostic performance of single-phase dual-energy CT (DECT) with virtual non-contrast CT (VNCT) compared with three-phase CT urography (CTU) in patients with haematuria. A total of 296 patients underwent three-phase CTU (NCT at 120 kVp; nephrographic phase and excretory phase DECTs at 140 kVp and 80 kVp) owing to haematuria. Diagnostic performances of CT scans were compared for detecting urothelial tumours and urinary stones. Dose-length product (DLP) was compared in relation to single-phase DECT and three-phase CTU Dose-length product (DLP) was compared in relation to single-phase DECT and three-phase CTU. Sensitivity and specificity for tumour were 95 % (19/20) and 98.9 % (273/276) on CTU, 95 % (19/20) and 98.2 % (271/276) on nephrographic phase DECT, and 90 % (18/20) and 98.2 % (271/276) on excretory phase DECT (P > 0.1). Of the 148 stones detected on NCT, 108 (73 %) and 100 (67.6 %) were detected on nephrographic phase and excretory phase VNCTs, respectively. The mean size of stones undetected on nephrographic and excretory VNCTs was measured as 1.5 ± 0.5 mm and 1.6 ± 0.6 mm, respectively. The mean DLPs of three-phase CTU, nephrographic phase DECT and excretory phase DECT were 1076 ± 248 mGy . cm, 410 ± 98 mGy . cm, and 360 ± 87 mGy . cm, respectively (P < 0.001). Single-phase DECT has a potential to replace three-phase CTU for detecting tumours with a lower radiation dose. (orig.)

  10. Deterministic nonlinear phase gates induced by a single qubit

    Science.gov (United States)

    Park, Kimin; Marek, Petr; Filip, Radim

    2018-05-01

    We propose deterministic realizations of nonlinear phase gates by repeating a finite sequence of non-commuting Rabi interactions between a harmonic oscillator and only a single two-level ancillary qubit. We show explicitly that the key nonclassical features of the ideal cubic phase gate and the quartic phase gate are generated in the harmonic oscillator faithfully by our method. We numerically analyzed the performance of our scheme under realistic imperfections of the oscillator and the two-level system. The methodology is extended further to higher-order nonlinear phase gates. This theoretical proposal completes the set of operations required for continuous-variable quantum computation.

  11. Single phase inverter for a three phase power generation and distribution system

    Science.gov (United States)

    Lindena, S. J.

    1976-01-01

    A breadboard design of a single-phase inverter with sinusoidal output voltage for a three-phase power generation and distribution system was developed. The three-phase system consists of three single-phase inverters, whose output voltages are connected in a delta configuration. Upon failure of one inverter the two remaining inverters will continue to deliver three-phase power. Parallel redundancy as offered by two three-phase inverters is substituted by one three-phase inverter assembly with high savings in volume, weight, components count and complexity, and a considerable increase in reliability. The following requirements must be met: (1) Each single-phase, current-fed inverter must be capable of being synchronized to a three-phase reference system such that its output voltage remains phaselocked to its respective reference voltage. (2) Each single-phase, current-fed inverter must be capable of accepting leading and lagging power factors over a range from -0.7 through 1 to +0.7.

  12. The Single-Phase ProtoDUNE Technical Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Abi, B. [Univ. of Padova (Italy); et al.

    2017-06-21

    ProtoDUNE-SP is the single-phase DUNE Far Detector prototype that is under construction and will be operated at the CERN Neutrino Platform (NP) starting in 2018. ProtoDUNE-SP, a crucial part of the DUNE effort towards the construction of the first DUNE 10-kt fiducial mass far detector module (17 kt total LAr mass), is a significant experiment in its own right. With a total liquid argon (LAr) mass of 0.77 kt, it represents the largest monolithic single-phase LArTPC detector to be built to date. It's technical design is given in this report.

  13. A complementary mobile phase approach based on the peak count concept oriented to the full resolution of complex mixtures.

    Science.gov (United States)

    Ortín, A; Torres-Lapasió, J R; García-Álvarez-Coque, M C

    2011-08-26

    Situations of minimal resolution are often found in liquid chromatography, when samples that contain a large number of compounds, or highly similar in terms of structure and/or polarity, are analysed. This makes full resolution with a single separation condition (e.g., mobile phase, gradient or column) unfeasible. In this work, the optimisation of the resolution of such samples in reversed-phase liquid chromatography is approached using two or more isocratic mobile phases with a complementary resolution behaviour (complementary mobile phases, CMPs). Each mobile phase is dedicated to the separation of a group of compounds. The CMPs are selected in such a way that, when the separation is considered globally, all the compounds in the sample are satisfactorily resolved. The search of optimal CMPs can be carried out through a comprehensive examination of the mobile phases in a selected domain. The computation time of this search has been reported to be substantially reduced by application of a genetic algorithm with local search (LOGA). A much simpler approach is here described, which is accessible to non-experts in programming, and offers solutions of the same quality as LOGA, with a similar computation time. The approach makes a sequential search of CMPs based on the peak count concept, which is the number of peaks exceeding a pre-established resolution threshold. The new approach is described using as test sample a mixture of 30 probe compounds, 23 of them with an ionisable character, and the pH and organic solvent contents as experimental factors. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. 30 CFR 77.806 - Connection of single-phase loads.

    Science.gov (United States)

    2010-07-01

    ... COAL MINES Surface High-Voltage Distribution § 77.806 Connection of single-phase loads. Single-phase loads, such as transformer primaries, shall be connected phase to phase in resistance grounded systems. ...

  15. 30 CFR 77.905 - Connection of single-phase loads.

    Science.gov (United States)

    2010-07-01

    ... COAL MINES Low- and Medium-Voltage Alternating Current Circuits § 77.905 Connection of single-phase loads. Single-phase loads shall be connected phase-to-phase in resistance grounded systems. ...

  16. Polarons and Mobile Impurities Near a Quantum Phase Transition

    Science.gov (United States)

    Shadkhoo, Shahriar

    This dissertation aims at improving the current understanding of the physics of mobile impurities in highly correlated liquid-like phases of matter. Impurity problems pose challenging and intricate questions in different realms of many-body physics. For instance, the problem of ''solvation'' of charged solutes in polar solvents, has been the subject of longstanding debates among chemical physicists. The significant role of quantum fluctuations of the solvent, as well as the break down of linear response theory, render the ordinary treatments intractable. Inspired by this complicated problem, we first attempt to understand the role of non-specific quantum fluctuations in the solvation process. To this end, we calculate the dynamic structure factor of a model polar liquid, using the classical Molecular Dynamics (MD) simulations. We verify the failure of linear response approximation in the vicinity of a hydrated electron, by comparing the outcomes of MD simulations with the predictions of linear response theory. This nonlinear behavior is associated with the pronounced peaks of the structure factor, which reflect the strong fluctuations of the local modes. A cavity picture is constructed based on heuristic arguments, which suggests that the electron, along with the surrounding polarization cloud, behave like a frozen sphere, for which the linear response theory is broken inside and valid outside. The inverse radius of the spherical region serves as a UV momentum cutoff for the linear response approximation to be applicable. The problem of mobile impurities in polar liquids can be also addressed in the framework of the ''polaron'' problem. Polaron is a quasiparticle that typically acquires an extended state at weak couplings, and crossovers to a self-trapped state at strong couplings. Using the analytical fits to the numerically obtained charge-charge structure factor, a phenomenological approach is proposed within the Leggett's influence functional formalism, which

  17. Single-shot quantitative phase microscopy with color-multiplexed differential phase contrast (cDPC.

    Directory of Open Access Journals (Sweden)

    Zachary F Phillips

    Full Text Available We present a new technique for quantitative phase and amplitude microscopy from a single color image with coded illumination. Our system consists of a commercial brightfield microscope with one hardware modification-an inexpensive 3D printed condenser insert. The method, color-multiplexed Differential Phase Contrast (cDPC, is a single-shot variant of Differential Phase Contrast (DPC, which recovers the phase of a sample from images with asymmetric illumination. We employ partially coherent illumination to achieve resolution corresponding to 2× the objective NA. Quantitative phase can then be used to synthesize DIC and phase contrast images or extract shape and density. We demonstrate amplitude and phase recovery at camera-limited frame rates (50 fps for various in vitro cell samples and c. elegans in a micro-fluidic channel.

  18. A Three-Dimensional Pore-Scale Model for Non-Wetting Phase Mobilization with Ferrofluid

    Science.gov (United States)

    Wang, N.; Prodanovic, M.

    2017-12-01

    Ferrofluid, a stable dispersion of paramagnetic nanoparticles in water, can generate a distributed pressure difference across the phase interface in an immiscible two-phase flow under an external magnetic field. In water-wet porous media, this non-uniform pressure difference may be used to mobilize the non-wetting phase, e.g. oil, trapped in the pores. Previous numerical work by Soares et al. of two-dimensional single-pore model showed enhanced non-wetting phase recovery with water-based ferrofluid under certain magnetic field directions and decreased recovery under other directions. However, the magnetic field selectively concentrates in the high magnetic permeability ferrofluid which fills the small corners between the non-wetting phase and the solid wall. The magnetic field induced pressure is proportional to the square of local magnetic field strength and its normal component, and makes a significant impact on the non-wetting phase deformation. The two-dimensional model omitted the effect of most of these corners and is not sufficient to compute the magnetic-field-induced pressure difference or to predict the non-wetting blob deformation. Further, it is not clear that 3D effects on magnetic field in an irregular geometry can be approximated in 2D. We present a three-dimensional immiscible two-phase flow model to simulate the deformation of a non-wetting liquid blob in a single pore filled with a ferrofluid under a uniform external magnetic field. The ferrofluid is modeled as a uniform single phase because the nanoparticles are 104 times smaller than the pore. The open source CFD solver library OpenFOAM is used for the simulations based on the volume of fluid method. Simulations are performed in a converging-diverging channel model on different magnetic field direction, different initial oil saturations, and different pore shapes. Results indicate that the external magnetic field always stretches the non-wetting blob away from the solid channel wall. A magnetic

  19. Effect of Mobile Phase Additives on the Resolution of Four Bioactive Compounds by RP-HPLC

    Directory of Open Access Journals (Sweden)

    Shengnan Li

    2010-05-01

    Full Text Available The use of mobile phase additives enhances the separation and resolution of the bioactive compounds on the C18 column. Chlorogenic acid, caffeic acid, rutin, and scoparone from Herba Artemisiae Scopariae were investigated as the target compounds. Acetic acid, triethylamine, inorganic salts, and several ionic liquids were added as mobile phase additives into methanol/water (40:60, v/v. The result revealed that a mobile phase with 0.01 mol/L of ionic liquid [BMIM][BF4] enabled the optimum separation of the four target compounds.

  20. Investigation of effect of single phase electrical faults at LOFT

    International Nuclear Information System (INIS)

    Yeates, J.A.

    1978-01-01

    This LTR presents the general basic engineering facts related to an open phase fault in a three phase power system commonly referred to as a single phase condition. It describes the probable results to electrical motors and describes the LOFT system design factors which minimize the likelihood of such a fault occurring at LOFT. It recognizes that the hazard of such a fault is a realistic threat and notes the types of relays designed to provide protection. Recommendations are made to perform a detailed engineering study to determine the most advantageous protective relay design, and to implement such a design by installation of the necessary devices and controls

  1. Ultrafast electric phase control of a single exciton qubit

    Science.gov (United States)

    Widhalm, Alex; Mukherjee, Amlan; Krehs, Sebastian; Sharma, Nandlal; Kölling, Peter; Thiede, Andreas; Reuter, Dirk; Förstner, Jens; Zrenner, Artur

    2018-03-01

    We report on the coherent phase manipulation of quantum dot excitons by electric means. For our experiments, we use a low capacitance single quantum dot photodiode which is electrically controlled by a custom designed SiGe:C BiCMOS chip. The phase manipulation is performed and quantified in a Ramsey experiment, where ultrafast transient detuning of the exciton energy is performed synchronous to double pulse π/2 ps laser excitation. We are able to demonstrate electrically controlled phase manipulations with magnitudes up to 3π within 100 ps which is below the dephasing time of the quantum dot exciton.

  2. 77 FR 57085 - Mobility Fund Phase I Auction; Release of Files with Recalculated Road Miles for Auction 901...

    Science.gov (United States)

    2012-09-17

    ... FEDERAL COMMUNICATIONS COMMISSION [AU Docket No. 12-25; DA 12-1446] Mobility Fund Phase I Auction... Mobility Fund Phase I support to be offered in Auction 901, which is to be held on September 27, 2012, and..., 77 FR 32092, May 31, 2012, the Bureaus identified census blocks eligible for the Mobility Fund Phase...

  3. 77 FR 11115 - Mobility Fund Phase I Auction Limited Extension of Deadlines for Comments and Reply Comments on...

    Science.gov (United States)

    2012-02-24

    ... FEDERAL COMMUNICATIONS COMMISSION [AU Docket No. 12-25; DA 12-236] Mobility Fund Phase I Auction... the Mobility Fund Phase I Auction Limited Extension of Comment Deadlines Public Notice (Public Notice... respect to the potential eligibility of specific census blocks for Mobility Fund Phase I support by March...

  4. A Transformer-less Single Phase Inverter For photovoltaic Systems

    DEFF Research Database (Denmark)

    Mostaan, Ali; Alizadeh, Ebrahim; Qu, Ying

    2017-01-01

    A single phase transformer-less inverter is introduced in this paper. The negative polarities of the input voltage and output terminal have common ground. Therefore, the leakage current problem that is common in PV systems is eliminated naturally. In addition, the proposed inverter has fewer comp...

  5. experimental implementation of single-phase, three-level, sinusoidal

    African Journals Online (AJOL)

    Page 1 ... of many multilevel inverter configurations. This paper presents an experimental report of a simplified topology for single-phase, SPWM, three-level voltage source inverter wit R-L load. To keep the power circuit ... employed in many industrial applications such as variable speed drives, uninterruptible power sup-.

  6. An Asymmetrical Space Vector Method for Single Phase Induction Motor

    DEFF Research Database (Denmark)

    Cui, Yuanhai; Blaabjerg, Frede; Andersen, Gert Karmisholt

    2002-01-01

    Single phase induction motors are the workhorses in low-power applications in the world, and also the variable speed is necessary. Normally it is achieved either by the mechanical method or by controlling the capacitor connected with the auxiliary winding. Any above method has some drawback which...

  7. Single-phase high-entropy alloys. An overview

    Energy Technology Data Exchange (ETDEWEB)

    Kozak, Roksolana; Steurer, Walter [ETH Zurich (Switzerland). Lab. of Crystallography; Sologubenko, Alla [ETH Zurich (Switzerland). Lab. of Nanotechnology

    2015-02-01

    The term 'high-entropy alloys (HEAs)' first appeared about 10 years ago defining alloys composed of n=5-13 principal elements with concentrations of approximately 100/n at.% each. Since then many equiatomic (or near equiatomic) single- and multi-phase multicomponent alloys were developed, which are reported for a combination of tunable properties: high hardness, strength and ductility, oxidation and wear resistance, magnetism, etc. In our paper, we focus on probably single-phase HEAs (solid solutions) out of all HEAs studied so far, discuss ways of their prediction, mechanical properties. In contrast to classical multielement/multiphase alloys, only single-phase multielement alloys (solid solutions) represent the basic concept underlying HEAs as mixing-entropy stabilized homogenous materials. The literature overview is complemented by own studies demonstrating that the alloys CrFeCoNi, CrFeCoNiAl{sub 0.3} and PdFeCoNi homogenized at 1300 and 1100 C, respectively, for 1 week are not single-phase HEAs, but a coherent mixture of two solid solutions.

  8. Solar-Based Boost Differential Single Phase Inverter | Eya | Nigerian ...

    African Journals Online (AJOL)

    Solar-Based Boost Differential Single Phase Inverter. ... Solar-based boost differential inverter is reduced down to 22.37% in closed loop system with the aid of Proportional –integral-Differential (PID) ... The dc power source is photovoltaic cell.

  9. A single phase photovoltaic inverter control for grid connected system

    Indian Academy of Sciences (India)

    This paper presents a control scheme for single phase grid connected photovoltaic (PV) system operating under both grid connected and isolated grid mode. The control techniques include voltage and current control of grid-tie PV inverter. During grid connected mode, grid controls the amplitude and frequency of the PV ...

  10. Flexible and Safe Control of Mobile Surface Systems, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The primary innovation of this work is a novel approach for flexible and safe control of highly capable mobile surface systems, such as long-duration science rovers,...

  11. Flexible and Safe Control of Mobile Surface Systems, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The primary innovation of this work is a novel Petri net based approach for safe and flexible control of highly capable mobile surface systems, such as long-duration...

  12. protoDUNE-Single Phase and protDUNE-DualPhase

    CERN Multimedia

    Brice, Maximilien

    2016-01-01

    At the EHN1 two big 8m x 8m x8m detector prototypes (protoDUNE-Single Phase and protDUNE-DualPhase) are being constructed. The aim is to test technologies and detector performances for DUNE, a new generation of LBN neutr

  13. 77 FR 14012 - Eligible Telecommunications Carrier Designation for Participation in Mobility Fund Phase I

    Science.gov (United States)

    2012-03-08

    ...; DA 12-271] Eligible Telecommunications Carrier Designation for Participation in Mobility Fund Phase I... Wireless Telecommunications and Wireline Competition Bureaus describe the process and requirements for applicants seeking Eligible Telecommunications Carrier (ETC) Designation from the Commission for...

  14. Use of low volatility mobile phases in electroosmotic thin-layer chromatography.

    Science.gov (United States)

    Berezkin, V G; Balushkin, A O; Tyaglov, B V; Litvin, E F

    2005-08-19

    A variant of electroosmotic thin-layer chromatography is suggested with the use of low volatility compounds as mobile phases aimed at drastically decreasing the evaporation of the mobile phase and improving the reproducibility of the method. The linear movement velocity of zones of separated compounds is experimentally shown to increase 2-12-fold in electroosmotic chromatography (compared to similar values in traditional TLC). The separation efficiency is also considerably increased.

  15. Navy Mobility Fuels Forecasting System. Phase I report

    Energy Technology Data Exchange (ETDEWEB)

    Davis, R.M.; Hadder, G.R.; Singh, S.P.N.; Whittle, C.

    1985-07-01

    The Department of the Navy (DON) requires an improved capability to forecast mobility fuel availability and quality. The changing patterns in fuel availability and quality are important in planning the Navy's Mobility Fuels R and D Program. These changes come about primarily because of the decline in the quality of crude oil entering world markets as well as the shifts in refinery capabilities domestically and worldwide. The DON requested ORNL's assistance in assembling and testing a methodology for forecasting mobility fuel trends. ORNL reviewed and analyzed domestic and world oil reserve estimates, production and price trends, and recent refinery trends. Three publicly available models developed by the Department of Energy were selected as the basis of the Navy Mobility Fuels Forecasting System. The system was used to analyze the availability and quality of jet fuel (JP-5) that could be produced on the West Coast of the United States under an illustrative business-as-usual and a world oil disruption scenario in 1990. Various strategies were investigated for replacing the lost JP-5 production. This exercise, which was strictly a test case for the forecasting system, suggested that full recovery of lost fuel production could be achieved by relaxing the smoke point specifications or by increasing the refiners' gate price for the jet fuel. A more complete analysis of military mobility fuel trends is currently under way.

  16. Study on the immunity state of mouse exposed to mobile phone radiation during embryonic phase

    International Nuclear Information System (INIS)

    Pei Yinhui; Gao Hui

    2008-01-01

    Objective: To study the effect of mobile phone radiation on mouse which exposed to radiation during embryonic phase. Methods: Pregnant mice were exposed to mobile phone radiation. The mice's netrophile phage percentage and spleen lymphocyte transformation rate were detected respectively 2 months after birth. Results: The netrophile phage percentage of experimental mice was seemly the same as that of control group, and there was no significant difference (P>0.05), but the spleen transformation rate showed the diverse trend. Conclusion: The specific cellular immunity of mice, which ex- posed to mobile phone radiation during embryonic phase, was seen to be in a state of decreasement. (authors)

  17. Laser doppler anemometry in single- and two-phase flows

    International Nuclear Information System (INIS)

    Durst, F.

    1976-01-01

    The present report gives an introduction into laser-Doppler anemometry and tries to explain the basic physical principles of this measuring technique. Moire fringe patterns are used in order to visually model LDA-signals and to explain the basic difference in optical systems. It is pointed out that LDA measurements in highly turbulent flows and in two-phase flows should be attempted with direction sensitive instruments only. Some of the optical systems developed by the author and his collaborators are introduced and their functioning in measurements is demonstrated. These measurements embrace investigations in a number of single-phase flows including flames. (orig.) [de

  18. Effect of grain boundary on the field-effect mobility of microrod single crystal organic transistors.

    Science.gov (United States)

    Kim, Jaekyun; Kang, Jingu; Cho, Sangho; Yoo, Byungwook; Kim, Yong-Hoon; Park, Sung Kyu

    2014-11-01

    High-performance microrod single crystal organic transistors based on a p-type 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) semiconductor are fabricated and the effects of grain boundaries on the carrier transport have been investigated. The spin-coating of C8-BTBT and subsequent solvent vapor annealing process enabled the formation of organic single crystals with high aspect ratio in the range of 10 - 20. It was found that the organic field-effect transistors (OFETs) based on these single crystals yield a field-effect mobility and an on/off current ratio of 8.04 cm2/Vs and > 10(5), respectively. However, single crystal OFETs with a kink, in which two single crystals are fused together, exhibited a noticeable drop of field-effect mobility, and we claim that this phenomenon results from the carrier scattering at the grain boundary.

  19. Pressure Drop Correlations of Single-Phase and Two-Phase Flow in Rolling Tubes

    International Nuclear Information System (INIS)

    Xia-xin Cao; Chang-qi Yan; Pu-zhen Gao; Zhong-ning Sun

    2006-01-01

    A series of experimental studies of frictional pressure drop for single phase and two-phase bubble flow in smooth rolling tubes were carried out. The tube inside diameters were 15 mm, 25 mm and 34.5 mm respectively, the rolling angles of tubes could be set as 10 deg. and 20 deg., and the rolling periods could be set as 5 s, 10 s and 15 s. Combining with the analysis of single-phase water motion, it was found that the traditional correlations for calculating single-phase frictional coefficient were not suitable for the rolling condition. Based on the experimental data, a new correlation for calculating single-phase frictional coefficient under rolling condition was presented, and the calculations not only agreed well with the experimental data, but also could display the periodically dynamic characteristics of frictional coefficients. Applying the new correlation to homogeneous flow model, two-phase frictional pressure drop of bubble flow in rolling tubes could be calculated, the results showed that the relative error between calculation and experimental data was less than ± 25%. (authors)

  20. Efficency of mobile authentication service technology on phase 1 ...

    African Journals Online (AJOL)

    Conclusion: The findings of this study revealed that some brands antimalarial and antibacterial drugs available in the Nigeria drug market still do not have MAS technology inscribed on them and efficiency of Mobile Authentication Service is directly a function of the competence of the service providers authorized to manage ...

  1. Overview of Single-Phase Grid-Connected Photovoltaic Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede

    2017-01-01

    A continuous booming installation of solar photovoltaic (PV) systems has been witnessed worldwide. It is mainly driven by the imperative demand of “clean” power generation from renewables. Grid-connected PV systems will thus become an even more active player in the future mixed power systems, which...... systems. This chapter thus gives an overview of the advancement of power electronics converters in single-phase grid-connected PV systems, being commonly used in residential applications. Demands to single-phase grid-connected PV systems and the general control strategies are also addressed...... are linked together by a vast of power electronics converters and the power grid. In order to achieve a reliable and efficient power generation from PV systems, more stringent demands have been imposed on the entire PV system. It, in return, advances the development of the power converter technology in PV...

  2. Permanent split capacitor single phase electric motor system

    Science.gov (United States)

    Kirschbaum, H.S.

    1984-08-14

    A permanent split capacitor single phase electric motor achieves balanced operation at more than one operating point by adjusting the voltage supplied to the main and auxiliary windings and adjusting the capacitance in the auxiliary winding circuit. An intermediate voltage tap on an autotransformer supplies voltage to the main winding for low speed operation while a capacitive voltage divider is used to adjust the voltage supplied to the auxiliary winding for low speed operation. 4 figs.

  3. Stability characteristics of a single-phase free convection loop

    Science.gov (United States)

    Creveling, H. F.; De Paz, J. F.; Baladi, J. Y.; Schoenhals, R. J.

    1975-01-01

    Experiments investigating the stability characteristics of a single-phase free convection loop are reported. Results of the study confirm the contention made by previous workers that instabilities near the thermodynamic critical point can occur for ordinary fluids as well as those with unusual behavior in the near-critical region. Such a claim runs counter to traditional beliefs, but it is supported by the observation of such instabilities for water at atmospheric pressure and moderate temperatures in the present work.

  4. Berry-phase blockade in single-molecule magnets

    OpenAIRE

    Gonzalez, Gabriel; Leuenberger, Michael N.

    2006-01-01

    We formulate the problem of electron transport through a single-molecule magnet (SMM) in the Coulomb blockade regime taking into account topological interference effects for the tunneling of the large spin of a SMM. The interference originates from spin Berry phases associated with different tunneling paths. We show that in the case of incoherent spin states it is essential to place the SMM between oppositely spin-polarized source and drain leads in order to detect the spin tunneling in the s...

  5. Single beam Fourier transform digital holographic quantitative phase microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Anand, A., E-mail: arun-nair-in@yahoo.com; Chhaniwal, V. K.; Mahajan, S.; Trivedi, V. [Optics Laboratory, Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Vadodara 390001 (India); Faridian, A.; Pedrini, G.; Osten, W. [Institut für Technische Optik, Universität Stuttgart, Pfaffenwaldring 9, 70569 Stuttgart (Germany); Dubey, S. K. [Siemens Technology and Services Pvt. Ltd, Corporate Technology—Research and Technology Centre, Bangalore 560100 (India); Javidi, B. [Department of Electrical and Computer Engineering, U-4157, University of Connecticut, Storrs, Connecticut 06269-2157 (United States)

    2014-03-10

    Quantitative phase contrast microscopy reveals thickness or height information of a biological or technical micro-object under investigation. The information obtained from this process provides a means to study their dynamics. Digital holographic (DH) microscopy is one of the most used, state of the art single-shot quantitative techniques for three dimensional imaging of living cells. Conventional off axis DH microscopy directly provides phase contrast images of the objects. However, this process requires two separate beams and their ratio adjustment for high contrast interference fringes. Also the use of two separate beams may make the system more vulnerable to vibrations. Single beam techniques can overcome these hurdles while remaining compact as well. Here, we describe the development of a single beam DH microscope providing whole field imaging of micro-objects. A hologram of the magnified object projected on to a diffuser co-located with a pinhole is recorded with the use of a commercially available diode laser and an arrayed sensor. A Fourier transform of the recorded hologram directly yields the complex amplitude at the image plane. The method proposed was investigated using various phase objects. It was also used to image the dynamics of human red blood cells in which sub-micrometer level thickness variation were measurable.

  6. 78 FR 61350 - Tribal Mobility Fund Phase I Auction (Auction 902); Short-Form Application Filing Window...

    Science.gov (United States)

    2013-10-03

    ... FEDERAL COMMUNICATIONS COMMISSION [AU Docket No. 13-53; DA 13-1986, DA 13-1978] Tribal Mobility... Access Division: For Tribal Mobility Fund Phase I questions: Patricia Robbins at (202) 418-0660. To... to $50 million in one-time Tribal Mobility Fund Phase I support, will now open at 12 noon Eastern...

  7. Spectral decomposition of single-tone-driven quantum phase modulation

    International Nuclear Information System (INIS)

    Capmany, Jose; Fernandez-Pousa, Carlos R

    2011-01-01

    Electro-optic phase modulators driven by a single radio-frequency tone Ω can be described at the quantum level as scattering devices where input single-mode radiation undergoes energy changes in multiples of ℎΩ. In this paper, we study the spectral representation of the unitary, multimode scattering operator describing these devices. The eigenvalue equation, phase modulation being a process preserving the photon number, is solved at each subspace with definite number of photons. In the one-photon subspace F 1 , the problem is equivalent to the computation of the continuous spectrum of the Susskind-Glogower cosine operator of the harmonic oscillator. Using this analogy, the spectral decomposition in F 1 is constructed and shown to be equivalent to the usual Fock-space representation. The result is then generalized to arbitrary N-photon subspaces, where eigenvectors are symmetrized combinations of N one-photon eigenvectors and the continuous spectrum spans the entire unit circle. Approximate normalizable one-photon eigenstates are constructed in terms of London phase states truncated to optical bands. Finally, we show that synchronous ultrashort pulse trains represent classical field configurations with the same structure as these approximate eigenstates, and that they can be considered as approximate eigenvectors of the classical formulation of phase modulation.

  8. Spectral decomposition of single-tone-driven quantum phase modulation

    Energy Technology Data Exchange (ETDEWEB)

    Capmany, Jose [ITEAM Research Institute, Univ. Politecnica de Valencia, 46022 Valencia (Spain); Fernandez-Pousa, Carlos R, E-mail: c.pousa@umh.es [Signal Theory and Communications, Department of Physics and Computer Science, Univ. Miguel Hernandez, 03202 Elche (Spain)

    2011-02-14

    Electro-optic phase modulators driven by a single radio-frequency tone {Omega} can be described at the quantum level as scattering devices where input single-mode radiation undergoes energy changes in multiples of {h_bar}{Omega}. In this paper, we study the spectral representation of the unitary, multimode scattering operator describing these devices. The eigenvalue equation, phase modulation being a process preserving the photon number, is solved at each subspace with definite number of photons. In the one-photon subspace F{sub 1}, the problem is equivalent to the computation of the continuous spectrum of the Susskind-Glogower cosine operator of the harmonic oscillator. Using this analogy, the spectral decomposition in F{sub 1} is constructed and shown to be equivalent to the usual Fock-space representation. The result is then generalized to arbitrary N-photon subspaces, where eigenvectors are symmetrized combinations of N one-photon eigenvectors and the continuous spectrum spans the entire unit circle. Approximate normalizable one-photon eigenstates are constructed in terms of London phase states truncated to optical bands. Finally, we show that synchronous ultrashort pulse trains represent classical field configurations with the same structure as these approximate eigenstates, and that they can be considered as approximate eigenvectors of the classical formulation of phase modulation.

  9. Anisotropic carrier mobility in single- and bi-layer C3N sheets

    Science.gov (United States)

    Wang, Xueyan; Li, Qingfang; Wang, Haifeng; Gao, Yan; Hou, Juan; Shao, Jianxin

    2018-05-01

    Based on the density functional theory combined with the Boltzmann transport equation with relaxation time approximation, we investigate the electronic structure and predict the carrier mobility of single- and bi-layer newly fabricated 2D carbon nitrides C3N. Although C3N sheets possess graphene-like planar hexagonal structure, the calculated carrier mobility is remarkably anisotropic, which is found mainly induced by the anisotropic effective masses and deformation potential constants. Importantly, we find that both the electron and hole mobilities are considerable high, for example, the hole mobility along the armchair direction of single-layer C3N sheets can arrive as high as 1.08 ×104 cm2 V-1 s-1, greatly larger than that of C2N-h2D and many other typical 2D materials. Owing to the high and anisotropic carrier mobility and appropriate band gap, single- and bi-layer semiconducting C3N sheets may have great potential applications in high performance electronic and optoelectronic devices.

  10. Hybrid Three-Phase/Single-Phase Microgrid Architecture with Power Management Capabilities

    DEFF Research Database (Denmark)

    Sun, Qiuye; Zhou, Jianguo; Guerrero, Josep M.

    2015-01-01

    With the fast proliferation of single-phase distributed generation (DG) units and loads integrated into residential microgrids, independent power sharing per phase and full use of the energy generated by DGs have become crucial. To address these issues, this paper proposes a hybrid microgrid...... architecture and its power management strategy. In this microgrid structure, a power sharing unit (PSU), composed of three single-phase back-to-back (SPBTB) converters, is proposed to be installed at the point of common coupling (PCC). The aim of the PSU is mainly to realize the power exchange and coordinated...... control of load power sharing among phases, as well as to allow fully utilization of the energy generated by DGs. Meanwhile, the method combining the modified adaptive backstepping-sliding mode control approach and droop control is also proposed to design the SPBTB system controllers. With the application...

  11. Effects of mobile vacancies on the dynamics of ordering and phase separation in nonconserved multicomponent systems

    DEFF Research Database (Denmark)

    Gilhøj, Henriette; Jeppesen, Claus; Mouritsen, Ole G.

    1995-01-01

    The effects of mobile vacancies on the dynamics of ordering processes and phase separation in multicomponent systems are studied via Monte Carlo simulations of a two-dimensional seven-state ferromagnetic Potts model with varying degrees of site dilution. The model displays phase equilibria...

  12. Hall mobility reduction in single-crystalline silicon gradually compensated by thermal donors activation

    Science.gov (United States)

    Veirman, J.; Dubois, S.; Enjalbert, N.; Garandet, J. P.; Heslinga, D. R.; Lemiti, M.

    2010-06-01

    This letter focuses on the variation of the Hall majority carrier mobility with the dopant compensation level in purely Boron-doped Czochralski grown silicon single crystals. Compensation was varied continuously at the sample scale via a step by step activation of the oxygen-based thermal donors. At room temperature, we show a strong drop in mobility for high compensation levels in both p- and n-type Si. Mobility models taking into account carrier scattering on ionized impurities and phonons could not reproduce this drop. We conclude that a specific effect of compensation must be taken into account to explain the observed behaviour. We qualitatively discuss physical mechanisms susceptible to reduce mobility in highly compensated Si.

  13. Development of a Lunar-Phase Observation System Based on Augmented Reality and Mobile Learning Technologies

    OpenAIRE

    Tarng, Wernhuar; Lin, Yu-Sheng; Lin, Chiu-Pin; Ou, Kuo-Liang

    2016-01-01

    Observing the lunar phase requires long-term involvement, and it is often obstructed by bad weather or tall buildings. In this study, a lunar-phase observation system is developed using the augmented reality (AR) technology and the sensor functions of GPS, electronic compass, and 3-axis accelerometer on mobile devices to help students observe and record lunar phases easily. By holding the mobile device towards the moon in the sky, the screen will show the virtual moon at the position of the r...

  14. Circularly Polarized Planar Helix Phased Antenna Array for 5G Mobile Terminals

    DEFF Research Database (Denmark)

    Syrytsin, Igor A.; Zhang, Shuai; Pedersen, Gert F.

    2017-01-01

    In this paper, a planar helix mobile phased antenna array is proposed for 5th generation communication systems with operating frequency of 28GHz. The proposed array displays circular polarization in the endfire direction. Over 65 degrees of axial ratio beamwidth and 7GHz of axial ratio bandwidth...... has been achieved in the proposed design. The coverage performance of the proposed phased antenna array has also been studied by using the coverage efficiency metric. Coverage efficiency of 50 % at 5 dBi gain is achieved by the proposed phased mobile antenna array....

  15. Reversed phase liquid chromatography with UV absorbance and flame ionization detection using a water mobile phase and a cyano propyl stationary phase Analysis of alcohols and chlorinated hydrocarbons.

    Science.gov (United States)

    Quigley, W W; Ecker, S T; Vahey, P G; Synovec, R E

    1999-10-01

    The development of liquid chromatography with a commercially available cyano propyl stationary phase and a 100% water mobile phase is reported. Separations were performed at ambient temperature, simplifying instrumental requirements. Excellent separation efficiency using a water mobile phase was achieved, for example N=18 800, or 75 200 m(-1), was obtained for resorcinol, at a retention factor of k'=4.88 (retention time of 9.55 min at 1 ml min(-1) for a 25 cmx4.6 mm i.d. column, packed with 5 mum diameter particles with the cyano propyl stationary phase). A separation via reversed phase liquid chromatography (RP-LC) with a 100% water mobile phase of six phenols and related compounds was compared to a separation of the same compounds by traditional RP-LC, using octadecylsilane (ODS), i.e. C18, bound to silica and an aqueous mobile phase modified with acetonitrile. Nearly identical analysis time was achieved for the separation of six phenols and related compounds using the cyano propyl stationary phase with a 100% water mobile phase, as compared to traditional RP-LC requiring a relatively large fraction of organic solvent modifier in the mobile phase (25% acetonitrile:75% water). Additional understanding of the retention mechanism with the 100% water mobile phase was obtained by relating measured retention factors of aliphatic alcohols, phenols and related compounds, and chlorinated hydrocarbons to their octanol:water partition coefficients. The retention mechanism is found to be consistent with a RP-LC mechanism coupled with an additional retention effect due to residual hydroxyl groups on the cyano propyl stationary phase. Advantages due to a 100% water mobile phase for the chemical analysis of alcohol mixtures and chlorinated hydrocarbons are reported. By placing an absorbance detector in-series and preceding a novel drop interface to a flame ionization detector (FID), selective detection of a separated mixture of phenols and related compounds and aliphatic

  16. Record mobility in transparent p-type tin monoxide films and devices by phase engineering

    KAUST Repository

    Caraveo-Frescas, Jesus Alfonso

    2013-06-25

    Here, we report the fabrication of nanoscale (15 nm) fully transparent p-type SnO thin film transistors (TFT) at temperatures as low as 180 C with record device performance. Specifically, by carefully controlling the process conditions, we have developed SnO thin films with a Hall mobility of 18.71 cm2 V-1 s-1 and fabricated TFT devices with a linear field-effect mobility of 6.75 cm2 V-1 s -1 and 5.87 cm2 V-1 s-1 on transparent rigid and translucent flexible substrates, respectively. These values of mobility are the highest reported to date for any p-type oxide processed at this low temperature. We further demonstrate that this high mobility is realized by careful phase engineering. Specifically, we show that phase-pure SnO is not necessarily the highest mobility phase; instead, well-controlled amounts of residual metallic tin are shown to substantially increase the hole mobility. A detailed phase stability map for physical vapor deposition of nanoscale SnO is constructed for the first time for this p-type oxide. © 2013 American Chemical Society.

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

    DEFF Research Database (Denmark)

    Qu, Hao; Yang, Xijun; Guo, Yougui

    2014-01-01

    Single-phase voltage source converter (VSC) is an important power electronic converter (PEC), including single-phase voltage source inverter (VSI), single-phase voltage source rectifier (VSR), single-phase active power filter (APF) and single-phase grid-connection inverter (GCI). Single-phase VSC...

  18. Kinematics and early migration in single-radius mobile- and fixed-bearing total knee prostheses

    NARCIS (Netherlands)

    Wolterbeek, N.; Garling, E.H.; Mertens, B.J.; Nelissen, R.G.H.H.; Valstar, E.R.

    2012-01-01

    Background The mobile-bearing variant of a single-radius design is assumed to provide more freedom of motion compared to the fixed-bearing variant because the insert does not restrict the natural movements of the femoral component. This would reduce the contact stresses and wear which in turn may

  19. Simulation of the phenomenon of single-phase and two-phase natural circulation

    International Nuclear Information System (INIS)

    Castrillo, Lazara Silveira

    1998-02-01

    Natural convection phenomenon is often used to remove the residual heat from the surfaces of bodies where the heat is generated e.g. during accidents or transients of nuclear power plants. Experimental study of natural circulation can be done in small scale experimental circuits and the results can be extrapolated for larger operational facilities. The numerical analysis of transients can be carried out by using large computational codes that simulate the thermohydraulic behavior in such facilities. The computational code RELAP5/MOD2, (Reactor Excursion and Leak Analysis Program) was developed by U.S. Nuclear Regulatory Commissions's. Division of Reactor Safety Research with the objective of analysis of transients and postulated accidents in the light water reactor (LWR) systems, including small and large ruptures with loss of coolant accidents (LOCA's). The results obtained by the simulation of single-phase and two-phase natural circulation, using the RELAP5/MOD2, are presented in this work. The study was carried out using the experimental circuit built at the 'Departamento de Engenharia Quimica da Escola Politecnica da Universidade de Sao Paulo'. In the circuit, two experiments were carried out with different conditions of power and mass flow, obtaining a single-phase regime with a level of power of 4706 W and flow of 5.10 -5 m 3 /s (3 l/min) and a two-phase regime with a level of power of 6536 W and secondary flow 2,33.10 -5 m 3 /s (1,4 l/min). The study allowed tio evaluate the capacity of the code for representing such phenomena as well as comparing the transients obtained theoretically with the experimental results. The comparative analysis shows that the code represents fairly well the single-phase transient, but the results for two-phase transients, starting from the nodalization and calibration used for the case single-phase transient, did not reproduce faithfully some experimental results. (author)

  20. Potential pitfalls of single phasing operation in a three phase distribution network

    Energy Technology Data Exchange (ETDEWEB)

    Narayanan, V S

    1986-07-01

    Finding it difficult to cope with the increased demand for electric power, some electricity boards have resorted to single phasing techniques in distribution system. This practice is harmful to the equipment in the power system. Some of the potential dangers associated with this undesirable practice are briefly discussed.

  1. Total robotic radical rectal resection with da Vinci Xi system: single docking, single phase technique.

    Science.gov (United States)

    Tamhankar, Anup Sunil; Jatal, Sudhir; Saklani, Avanish

    2016-12-01

    This study aims to assess the advantages of Da Vinci Xi system in rectal cancer surgery. It also assesses the initial oncological outcomes after rectal resection with this system from a tertiary cancer center in India. Robotic rectal surgery has distinct advantages over laparoscopy. Total robotic resection is increasing following the evolution of hybrid technology. The latest Da Vinci Xi system (Intuitive Surgical, Sunnyvale, USA) is enabled with newer features to make total robotic resection possible with single docking and single phase. Thirty-six patients underwent total robotic resection in a single phase and single docking. We used newer port positions in a straight line. Median distance from the anal verge was 4.5 cm. Median robotic docking time and robotic procedure time were 9 and 280 min, respectively. Median blood loss was 100 mL. One patient needed conversion to an open approach due to advanced disease. Circumferential resection margin and longitudinal resection margins were uninvolved in all other patients. Median lymph node yield was 10. Median post-operative stay was 7 days. There were no intra-operative adverse events. The latest Da Vinci Xi system has made total robotic rectal surgery feasible in single docking and single phase. With the new system, four arm total robotic rectal surgery may replace the hybrid technique of laparoscopic and robotic surgery for rectal malignancies. The learning curve for the new system appears to be shorter than anticipated. Early perioperative and oncological outcomes of total robotic rectal surgery with the new system are promising. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  2. Phonon-limited mobility in n-type single-layer MoS2 from first principles

    DEFF Research Database (Denmark)

    Kaasbjerg, Kristen; Thygesen, Kristian S.; Jacobsen, Karsten W.

    2012-01-01

    We study the phonon-limited mobility in intrinsic n-type single-layer MoS2 for temperatures T > 100 K. The materials properties including the electron-phonon interaction are calculated from first principles and the deformation potentials and Frohlich interaction in single-layer MoS2 are established...... to recent experimental findings for the mobility in single-layer MoS2 (similar to 200 cm(2)V(-1)s(-1)), our results indicate that mobilities close to the intrinsic phonon-limited mobility can be achieved in two-dimensional materials via dielectric engineering that effectively screens static Coulomb...

  3. Ultrafast Switching Superjunction MOSFETs for Single Phase PFC Applications

    DEFF Research Database (Denmark)

    Hernandez Botella, Juan Carlos; Petersen, Lars Press; Andersen, Michael A. E.

    2014-01-01

    This paper presents a guide on characterizing state-of-the-art silicon superjunction (SJ) devices in the 600V range for single phase power factor correction (PFC) applications. The characterization procedure is based on a minimally inductive double pulse tester (DPT) with a very low intrusive...... current measurement method, which enables reaching the switching speed limits of these devices. Due to the intrinsic low and non-linear capacitances in vertical SJ MOSFETs, special attention needs to be paid to the gate drive design to minimize oscillations and limit the maximum at turn off. This paper...

  4. Critical flow rate in a single phase flow. Blocking concept

    International Nuclear Information System (INIS)

    Giot, Michel

    1978-01-01

    After referring to the phenomena accompanying the appearance of a critical flow rate in a nozzle and presenting equations governing single phase flows, the critical condition is defined. Several particular cases are then examined; the horizontal and vertical isentropic flow, Fanno's flow and Raleigh's and the isothermal flow. The entropy deviation is calculated on either side of a normal impact. To conclude, the link existing between the concepts of critical flow and the propagation rate of small perturbations is demonstrated. To do so, the method of perturbations, that of Prandtl and that of characteristic directions are applied in turn [fr

  5. Berry-Phase Blockade in Single-Molecule Magnets

    Science.gov (United States)

    González, Gabriel; Leuenberger, Michael N.

    2007-06-01

    We formulate the problem of electron transport through a single-molecule magnet (SMM) in the Coulomb blockade regime taking into account topological interference effects for the tunneling of the large spin of a SMM. The interference originates from spin Berry phases associated with different tunneling paths. We show that, in the case of incoherent spin states, it is essential to place the SMM between oppositely spin-polarized source and drain leads in order to detect the spin tunneling in the stationary current, which exhibits topological zeros as a function of the transverse magnetic field.

  6. Mobility-limiting mechanisms in single and dual channel strained Si/SiGe MOSFETs

    International Nuclear Information System (INIS)

    Olsen, S.H.; Dobrosz, P.; Escobedo-Cousin, E.; Bull, S.J.; O'Neill, A.G.

    2005-01-01

    Dual channel strained Si/SiGe CMOS architectures currently receive great attention due to maximum performance benefits being predicted for both n- and p-channel MOSFETs. Epitaxial growth of a compressively strained SiGe layer followed by tensile strained Si can create a high mobility buried hole channel and a high mobility surface electron channel on a single relaxed SiGe virtual substrate. However, dual channel n-MOSFETs fabricated using a high thermal budget exhibit compromised mobility enhancements compared with single channel devices, in which both electron and hole channels form in strained Si. This paper investigates the mobility-limiting mechanisms of dual channel structures. The first evidence of increased interface roughness due to the introduction of compressively strained SiGe below the tensile strained Si channel is presented. Interface corrugations degrade electron mobility in the strained Si. Roughness measurements have been carried out using AFM and TEM. Filtering AFM images allowed roughness at wavelengths pertinent to carrier transport to be studied and the results are in agreement with electrical data. Furthermore, the first comparison of strain measurements in the surface channels of single and dual channel architectures is presented. Raman spectroscopy has been used to study channel strain both before and after processing and indicates that there is no impact of the buried SiGe layer on surface macrostrain. The results provide further evidence that the improved performance of the single channel devices fabricated using a high thermal budget arises from improved surface roughness and reduced Ge diffusion into the Si channel

  7. An investigation of subchannel analysis models for single-phase and two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Dae Hyun

    1996-01-01

    The governing equations and lateral transport modelings of subchannel analysis code, which is the most widely used tool for the analysis of thermal hydraulics fields in reactor cores, have been thoroughly investigated in this study. The procedure for the derivation of subchannel integral balance equations from the local instantaneous phase equations was investigated by stages. The characteristics of governing equations according to the treatment of phase velocity were studies, and the equations based on the drift-flux equilibrium formulation have been derived. Turbulent mixing and void drift modeling, which affect considerably to the accuracy of subchannel analysis code, have been reviewed. In addition, some representative modelings of single-phase and two-phase turbulent mixing models have been introduced. (author). 5 tabs., 4 figs., 16 refs.

  8. Adaptive nonlinear control of single-phase to three-phase UPS system

    Directory of Open Access Journals (Sweden)

    Kissaoui M.

    2014-01-01

    Full Text Available This work deals with the problems of uninterruptible power supplies (UPS based on the single-phase to three-phase converters built in two stages: an input bridge rectifier and an output three phase inverter. The two blocks are joined by a continuous intermediate bus. The objective of control is threefold: i power factor correction “PFC”, ii generating a symmetrical three-phase system at the output even if the load is unknown, iii regulating the DC bus voltage. The synthesis of controllers has been reached by two nonlinear techniques that are the sliding mode and adaptive backstepping control. The performances of regulators have been validated by numerical simulation in MATLAB / SIMULINK.

  9. Differentiating the growth phases of single bacteria using Raman spectroscopy

    Science.gov (United States)

    Strola, S. A.; Marcoux, P. R.; Schultz, E.; Perenon, R.; Simon, A.-C.; Espagnon, I.; Allier, C. P.; Dinten, J.-M.

    2014-03-01

    In this paper we present a longitudinal study of bacteria metabolism performed with a novel Raman spectrometer system. Longitudinal study is possible with our Raman setup since the overall procedure to localize a single bacterium and collect a Raman spectrum lasts only 1 minute. Localization and detection of single bacteria are performed by means of lensfree imaging, whereas Raman signal (from 600 to 3200 cm-1) is collected into a prototype spectrometer that allows high light throughput (HTVS technology, Tornado Spectral System). Accomplishing time-lapse Raman spectrometry during growth of bacteria, we observed variation in the net intensities for some band groups, e.g. amides and proteins. The obtained results on two different bacteria species, i.e. Escherichia coli and Bacillus subtilis clearly indicate that growth affects the Raman chemical signature. We performed a first analysis to check spectral differences and similarities. It allows distinguishing between lag, exponential and stationary growth phases. And the assignment of interest bands to vibration modes of covalent bonds enables the monitoring of metabolic changes in bacteria caused by growth and aging. Following the spectra analysis, a SVM (support vector machine) classification of the different growth phases is presented. In sum this longitudinal study by means of a compact and low-cost Raman setup is a proof of principle for routine analysis of bacteria, in a real-time and non-destructive way. Real-time Raman studies on metabolism and viability of bacteria pave the way for future antibiotic susceptibility testing.

  10. Modelling a single phase voltage controlled rectifier using Laplace transforms

    Science.gov (United States)

    Kraft, L. Alan; Kankam, M. David

    1992-01-01

    The development of a 20 kHz, AC power system by NASA for large space projects has spurred a need to develop models for the equipment which will be used on these single phase systems. To date, models for the AC source (i.e., inverters) have been developed. It is the intent of this paper to develop a method to model the single phase voltage controlled rectifiers which will be attached to the AC power grid as an interface for connected loads. A modified version of EPRI's HARMFLO program is used as the shell for these models. The results obtained from the model developed in this paper are quite adequate for the analysis of problems such as voltage resonance. The unique technique presented in this paper uses the Laplace transforms to determine the harmonic content of the load current of the rectifier rather than a curve fitting technique. Laplace transforms yield the coefficient of the differential equations which model the line current to the rectifier directly.

  11. SINGLE-PHASE AND TWO-PHASE SECONDARY COOLANTS: SIMULATION AND EVALUATION OF THEIR THERMOPHYSICAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    Pedro Samuel Gomes Medeiros

    2011-09-01

    Full Text Available This paper makes a comparative analysis of the thermophysical properties of ice slurry with conventional single-phase secondary fluids used in thermal storage cooling systems. The ice slurry is a two-phase fluid consisting of water, antifreeze and ice crystals. It is a new technology that has shown great energy potential. In addition to transporting energy as a heat transfer fluid, it has thermal storage properties due to the presence of ice, storing coolness by latent heat of fusion. The single-phase fluids analyzed are water-NaCl and water-propylene glycol solutions, which also operate as carrier fluids in ice slurry. The presence of ice changes the thermophysical properties of aqueous solutions and a number of these properties were determined: density, thermal conductivity and dynamic viscosity. Data were obtained by software simulation. The results show that the presence of 10% by weight of ice provides a significant increase in thermal conductivity and dynamic viscosity, without causing changes in density. The rheological behavior of ice slurries, associated with its high viscosity, requires higher pumping power; however, this was not significant because higher thermal conductivity allows a lower mass flow rate without the use of larger pumps. Thus, the ice slurry ensures its high potential as a secondary fluid in thermal storage cooling systems, proving to be more efficient than single-phase secondary fluids.

  12. High p-type doping, mobility, and photocarrier lifetime in arsenic-doped CdTe single crystals

    Science.gov (United States)

    Nagaoka, Akira; Kuciauskas, Darius; McCoy, Jedidiah; Scarpulla, Michael A.

    2018-05-01

    Group-V element doping is promising for simultaneously maximizing the hole concentration and minority carrier lifetime in CdTe for thin film solar cells, but there are roadblocks concerning point defects including the possibility of self-compensation by AX metastability. Herein, we report on doping, lifetime, and mobility of CdTe single crystals doped with As between 1016 and 1020 cm-3 grown from the Cd solvent by the travelling heater method. Evidence consistent with AX instability as a major contributor to compensation in samples doped below 1017 cm-3 is presented, while for higher-doped samples, precipitation of a second phase on planar structural defects is also observed and may explain spatial variation in properties such as lifetime. Rapid cooling after crystal growth increases doping efficiency and mobility for times up to 20-30 days at room temperature with the highest efficiencies observed close to 45% and a hole mobility of 70 cm2/Vs at room temperature. A doping limit in the low 1017/cm3 range is observed for samples quenched at 200-300 °C/h. Bulk minority carrier lifetimes exceeding 20 ns are observed for samples doped near 1016 cm-3 relaxed in the dark and for unintentionally doped samples, while a lifetime of nearly 5 ns is observed for 1018 cm-3 As doping. These results help us to establish limits on properties expected for group-V doped CdTe polycrystalline thin films for use in photovoltaics.

  13. POOR HEMOPOIETIC STEM CELL MOBILIZERS IN MULTIPLE MYELOMA : A SINGLE INSTITUTION EXPERIENCE

    Directory of Open Access Journals (Sweden)

    Guillermo Jose Ruiz-Delgado

    2010-06-01

    Full Text Available In a single institution, in a group of 28 myeloma patients deemed eligible for autologous transplant, stem cell mobilization was attempted using filgrastim: 26 individuals were given 31 autografts employing 1-4 (median three apheresis sessions, to obtain a target stem cell dose of 1 x 106 CD34 viable cells / Kg of the recipient. The median number of grafted CD34 cells was 7.56 x 106  / Kg of the recipient; the range being 0.92 to 14.8.  By defining as poor mobilizers individuals in which a cell collection of 1 x 106 CD34 viable cells / Kg was better (80% at 80 months than those grafted with < 1 x 106 CD34 viable cells / Kg (67% at 76 months. Methods to improve stem cell mobilization are needed and may result in obtaining better results when autografting multiple myeloma patients.

  14. Single phase and two-phase flow pressure losses through restrictions, expansions and inserts

    International Nuclear Information System (INIS)

    Glenat, P.; Solignac, P.

    1984-11-01

    We give a selection of methods to predict pressure losses through retrictions, expansions and inserts. In single phase flow, we give the classical method based on the one-dimensional momentum and mass balances. In two-phase flow, we propose the method given by Harshe et al. and an empirical approach suggested by Chisholm. We notice the distinction between long and short inserts depends upon wether or not the vena contracta lies within insert. Finally, we propose three correlations to calculate void fraction through the singularities which have been considered [fr

  15. Single-Phase Phase-Locked Loop Based on Derivative Elements

    DEFF Research Database (Denmark)

    Guan, Qingxin; Zhang, Yu; Kang, Yong

    2017-01-01

    High-performance phase-locked loops (PLLs) are critical for power control in grid-connected systems. This paper presents a new method of designing a PLL for single-phase systems based on derivative elements (DEs). The quadrature signal generator (QSG) is constructed by two DEs with the same...... PLL to achieve high performance when the grid frequency changes rapidly. This paper presents the model of the PLL and a theoretical performance analysis with respect to both the frequency-domain and time-domain behavior. The error arising from the discretization process is also compensated, ensuring...

  16. Equivalence of two models in single-phase multicomponent flow simulations

    KAUST Repository

    Wu, Yuanqing

    2016-02-28

    In this work, two models to simulate the single-phase multicomponent flow in reservoirs are introduced: single-phase multicomponent flow model and two-phase compositional flow model. Because the single-phase multicomponent flow is a special case of the two-phase compositional flow, the two-phase compositional flow model can also simulate the case. We compare and analyze the two models when simulating the single-phase multicomponent flow, and then demonstrate the equivalence of the two models mathematically. An experiment is also carried out to verify the equivalence of the two models.

  17. Equivalence of two models in single-phase multicomponent flow simulations

    KAUST Repository

    Wu, Yuanqing; Sun, Shuyu

    2016-01-01

    In this work, two models to simulate the single-phase multicomponent flow in reservoirs are introduced: single-phase multicomponent flow model and two-phase compositional flow model. Because the single-phase multicomponent flow is a special case of the two-phase compositional flow, the two-phase compositional flow model can also simulate the case. We compare and analyze the two models when simulating the single-phase multicomponent flow, and then demonstrate the equivalence of the two models mathematically. An experiment is also carried out to verify the equivalence of the two models.

  18. Time domain spectral phase encoding/DPSK data modulation using single phase modulator for OCDMA application.

    Science.gov (United States)

    Wang, Xu; Gao, Zhensen; Kataoka, Nobuyuki; Wada, Naoya

    2010-05-10

    A novel scheme using single phase modulator for simultaneous time domain spectral phase encoding (SPE) signal generation and DPSK data modulation is proposed and experimentally demonstrated. Array- Waveguide-Grating and Variable-Bandwidth-Spectrum-Shaper based devices can be used for decoding the signal directly in spectral domain. The effects of fiber dispersion, light pulse width and timing error on the coding performance have been investigated by simulation and verified in experiment. In the experiment, SPE signal with 8-chip, 20GHz/chip optical code patterns has been generated and modulated with 2.5 Gbps DPSK data using single modulator. Transmission of the 2.5 Gbps data over 34km fiber with BEROCDMA) and secure optical communication applications. (c) 2010 Optical Society of America.

  19. Simplified paraboloid phase model-based phase tracker for demodulation of a single complex fringe.

    Science.gov (United States)

    He, A; Deepan, B; Quan, C

    2017-09-01

    A regularized phase tracker (RPT) is an effective method for demodulation of single closed-fringe patterns. However, lengthy calculation time, specially designed scanning strategy, and sign-ambiguity problems caused by noise and saddle points reduce its effectiveness, especially for demodulating large and complex fringe patterns. In this paper, a simplified paraboloid phase model-based regularized phase tracker (SPRPT) is proposed. In SPRPT, first and second phase derivatives are pre-determined by the density-direction-combined method and discrete higher-order demodulation algorithm, respectively. Hence, cost function is effectively simplified to reduce the computation time significantly. Moreover, pre-determined phase derivatives improve the robustness of the demodulation of closed, complex fringe patterns. Thus, no specifically designed scanning strategy is needed; nevertheless, it is robust against the sign-ambiguity problem. The paraboloid phase model also assures better accuracy and robustness against noise. Both the simulated and experimental fringe patterns (obtained using electronic speckle pattern interferometry) are used to validate the proposed method, and a comparison of the proposed method with existing RPT methods is carried out. The simulation results show that the proposed method has achieved the highest accuracy with less computational time. The experimental result proves the robustness and the accuracy of the proposed method for demodulation of noisy fringe patterns and its feasibility for static and dynamic applications.

  20. 77 FR 15369 - Mobility Fund Phase I Auction GIS Data of Potentially Eligible Census Blocks

    Science.gov (United States)

    2012-03-15

    ... GIS Data of Potentially Eligible Census Blocks AGENCY: Federal Communications Commission. ACTION... Bureaus (the ``Bureaus'') announce the availability of geographic information system (GIS) data for the...). SUPPLEMENTARY INFORMATION: This is a summary of the Mobility Fund Phase I Auction GIS Data for Potentially...

  1. Switchable Phased Antenna Array with Passive Elements for 5G Mobile Terminals

    DEFF Research Database (Denmark)

    Syrytsin, Igor A.; Zhang, Shuai; Pedersen, Gert F.

    2017-01-01

    In this paper, a reconfigurable phased antenna array system is constructed for the mobile terminals in the context of 5G communication system. The proposed antenna system operates at the resonance frequency of 28 GHz. The reconfigurability of the antenna element is achieved by using a passive slot...

  2. Evaluating the Onboarding Phase of Free-toPlay Mobile Games

    DEFF Research Database (Denmark)

    Weigert Petersen, Falko; Thomsen, Line Ebdrup; Mirza-Babaei, Pejman

    2017-01-01

    . This paper presents a study utilizing a lab-based mixed-methods approach in providing insights for evaluating the user experience of onboarding phases in mobile games. This includes an investigation into the contribution of physiological measures (Heart-Rate Variability and Galvanic Skin Conductance) as well...

  3. 77 FR 73586 - Further Inquiry Into Issues Related to Mobility Fund Phase II

    Science.gov (United States)

    2012-12-11

    ... highest cost areas. 17. Small business participation. In the USF/ICC Transformation Order and FNPRM, the... Phase II of the Mobility Fund. As established in the USF/ICC Transformation Order and FNPRM, 76 FC 78383... previously filed in response to the USF/ICC Transformation Order and FNPRM and the Bureaus' experience in...

  4. A 28 GHz FR-4 Compatible Phased Array Antenna for 5G Mobile Phone Applications

    DEFF Research Database (Denmark)

    Ojaroudiparchin, Naser; Shen, Ming; Pedersen, Gert F.

    2015-01-01

    The design of a 28 GHz phased array antenna for future fifth generation (5G) mobile-phone applications has been presented in this paper. The proposed antenna can be implemented using low cost FR-4 substrates, while maintaining good performance in terms of gain and efficiency. This is achieved...

  5. 78 FR 45071 - Annual Report for Mobility Fund Phase I Support and Record Retention

    Science.gov (United States)

    2013-07-26

    ... Record Retention, adopted as part of the Connect America Fund & Intercarrier Compensation Reform Order... Communications Commission released a Report and Order in the Universal Service Fund & Intercarrier Compensation... for Mobility Fund Phase I Support and Record Retention AGENCY: Federal Communications Commission...

  6. MECHANICAL CHARACTERISTICS OF THREE-PHASE INDUCTION MOTORS WITH SINGLE-PHASE POWER SUPPLY

    Directory of Open Access Journals (Sweden)

    V.S. Malyar

    2016-06-01

    Full Text Available Aim. Development of a method for calculating mechanical characteristics of three-phase induction motors with single-phase power supply. Methods. The developed algorithm is based on the high-adequacy mathematical model of motor and projection method for solving the boundary problem for equations of electrical circuits balance presented in the three-phase coordinate system. As a result of asymmetry of power supply to the stator windings, in steady state, flux-linkage and current change according to the periodic law. They are determined by solving the boundary problem. Results. The developed mathematical model allows determining periodic dependence of coordinates as a function of slip and, based on them, mechanical characteristics of motors. Academic novelty. The developed method relies on a completely new mathematical approach to calculation of stationary modes of nonlinear electromagnetic circuits, which allows obtaining periodic solution in a timeless domain. Practical value. Using the developed calculation algorithm, one can select capacitance required to start an induction motor with single-phase power supply and calculate static mechanical characteristics at a given capacitance.

  7. Single Photon Sensitive HgCdTe Avalanche Photodiode Detector (APD), Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Leveraging Phase I SBIR successes, in Phase II, a single photon sensitive LIDAR receiver will be fabricated and delivered to NASA. In Phase I, high-gain,...

  8. Structure and single-phase regime of boron carbides

    International Nuclear Information System (INIS)

    Emin, D.

    1988-01-01

    The boron carbides are composed of twelve-atom icosahedral clusters which are linked by direct covalent bonds and through three-atom intericosahedral chains. The boron carbides are known to exist as a single phase with carbon concentrations from about 8 to about 20 at. %. This range of carbon concentrations is made possible by the substitution of boron and carbon atoms for one another within both the icosahedra and intericosahedral chains. The most widely accepted structural model for B 4 C (the boron carbide with nominally 20% carbon) has B/sub 11/C icosahedra with C-B-C intericosahedral chains. Here, the free energy of the boron carbides is studied as a function of carbon concentration by considering the effects of replacing carbon atoms within B 4 C with boron atoms. It is concluded that entropic and energetic considerations both favor the replacement of carbon atoms with boron atoms within the intericosahedral chains, C-B-C→C-B-B. Once the carbon concentration is so low that the vast majority of the chains are C-B-B chains, near B/sub 13/C 2 , subsequent substitutions of carbon atoms with boron atoms occur within the icosahedra, B/sub 11/C→B/sub 12/. Maxima of the free energy occur at the most ordered compositions: B 4 C,B/sub 13/C 2 ,B/sub 14/C. This structural model, determined by studying the free energy, agrees with that previously suggested by analysis of electronic and thermal transport data. These considerations also provide an explanation for the wide single-phase regime found for boron carbides

  9. A grid-connected single-phase photovoltaic micro inverter

    Science.gov (United States)

    Wen, X. Y.; Lin, P. J.; Chen, Z. C.; Wu, L. J.; Cheng, S. Y.

    2017-11-01

    In this paper, the topology of a single-phase grid-connected photovoltaic (PV) micro-inverter is proposed. The PV micro-inverter consists of DC-DC stage with high voltage gain boost and DC-AC conversion stage. In the first stage, we apply the active clamp circuit and two voltage multipliers to achieve soft switching technology and high voltage gain. In addition, the flower pollination algorithm (FPA) is employed for the maximum power point tracking (MPPT) in the PV module in this stage. The second stage cascades a H-bridge inverter and LCL filter. To feed high quality sinusoidal power into the grid, the software phase lock, outer voltage loop and inner current loop control method are adopted as the control strategy. The performance of the proposed topology is tested by Matlab/Simulink. A PV module with maximum power 300W and maximum power point voltage 40V is applied as the input source. The simulation results indicate that the proposed topology and the control strategy are feasible.

  10. 78 FR 68839 - Tribal Mobility Fund Phase I Auction Rescheduled for February 25, 2014; Notice of Changes to...

    Science.gov (United States)

    2013-11-15

    ... FEDERAL COMMUNICATIONS COMMISSION [AU Docket No. 13-53; DA 13-2057] Tribal Mobility Fund Phase I Auction Rescheduled for February 25, 2014; Notice of Changes to Auction 902 Schedule Following Resumption... up to $50 million in one-time Tribal Mobility Fund Phase I support, will be conducted on February 25...

  11. 77 FR 33097 - Application To Participate in an Auction for Mobility Fund Phase I Support and Application for...

    Science.gov (United States)

    2012-06-05

    ... America Fund & Intercarrier Compensation Reform Order (Order), FCC 11-161 and a Bureau Order, DA 12-147...-147] Application To Participate in an Auction for Mobility Fund Phase I Support and Application for Mobility Fund Phase I Support AGENCY: Federal Communications Commission. ACTION: Final rule; announcement...

  12. A Simple Interface for 3D Position Estimation of a Mobile Robot with Single Camera.

    Science.gov (United States)

    Chao, Chun-Tang; Chung, Ming-Hsuan; Chiou, Juing-Shian; Wang, Chi-Jo

    2016-03-25

    In recent years, there has been an increase in the number of mobile robots controlled by a smart phone or tablet. This paper proposes a visual control interface for a mobile robot with a single camera to easily control the robot actions and estimate the 3D position of a target. In this proposal, the mobile robot employed an Arduino Yun as the core processor and was remote-controlled by a tablet with an Android operating system. In addition, the robot was fitted with a three-axis robotic arm for grasping. Both the real-time control signal and video transmission are transmitted via Wi-Fi. We show that with a properly calibrated camera and the proposed prototype procedures, the users can click on a desired position or object on the touchscreen and estimate its 3D coordinates in the real world by simple analytic geometry instead of a complicated algorithm. The results of the measurement verification demonstrates that this approach has great potential for mobile robots.

  13. Taxonomy and Analysis of IP Micro-Mobility Protocols in Single and Simultaneous Movements Scenarios

    Directory of Open Access Journals (Sweden)

    G. De Marco

    2007-01-01

    Full Text Available The micro-mobility is an important aspect in mobile communications, where the applications are anywhere and used anytime. One of the problems of micro-mobility is the hand-off latency. In this paper, we analyse two solutions for IP micro-mobility by means of a general taxonomy. The first one is based on the Stream Control Transmission Protocol (SCTP, which allows the dynamic address configuration of an association. The second one is based on the Session Initiation Protocol (SIP, which is the most popular protocol for multimedia communications over IP networks. We show that for the SCTP solution, there is room for further optimisations of the hand-off latency by adding slight changes to the protocol. However, as full end-to-end solution, SCTP is not able to handle simultaneous movement of hosts, whose probability in general cannot be neglected. On the other hand, the SIP can handle both single and simultaneous movements cases, although the hand-off latency can increase with respect to the SCTP solution. We show that for a correct and fast hand-off, the SIP server should be statefull.

  14. A Simple Interface for 3D Position Estimation of a Mobile Robot with Single Camera

    Directory of Open Access Journals (Sweden)

    Chun-Tang Chao

    2016-03-01

    Full Text Available In recent years, there has been an increase in the number of mobile robots controlled by a smart phone or tablet. This paper proposes a visual control interface for a mobile robot with a single camera to easily control the robot actions and estimate the 3D position of a target. In this proposal, the mobile robot employed an Arduino Yun as the core processor and was remote-controlled by a tablet with an Android operating system. In addition, the robot was fitted with a three-axis robotic arm for grasping. Both the real-time control signal and video transmission are transmitted via Wi-Fi. We show that with a properly calibrated camera and the proposed prototype procedures, the users can click on a desired position or object on the touchscreen and estimate its 3D coordinates in the real world by simple analytic geometry instead of a complicated algorithm. The results of the measurement verification demonstrates that this approach has great potential for mobile robots.

  15. Analytical prediction of the electromagnetic torques in single-phase and two-phase ac motors

    Energy Technology Data Exchange (ETDEWEB)

    Popescu, M.

    2004-07-01

    The single-phase and two-phase versions of AC motors can be modelled by means of the two-axis (d-q) theory with sufficient accuracy when the equivalent circuit parameters are correctly estimated. This work attempts to present a unified approach to the analytical prediction of the electromagnetic torque of these machines. Classical d-q axes formulation requires that the reference frame should be fixed on the frame where the asymmetries arise, i.e. the stator and rotor. The asynchronous torques that characterize the induction motors are modelled in a stationary reference frame, where the d-q axes coincide with the physical magnetic axes of the stator windings. For the permanent magnet motors, that may exhibit asymmetries on both stator and rotor, the proposed solution includes: a series of frame transformations, followed by symmetrical components decomposition. As in single-phase and two-phase systems the homopolar component is zero; each symmetrical component - negative and positive - is further analysed using d-q axes theory. The superposition principle is employed to consider the magnets and rotor cage effects. The developed models account for the most important asymmetries of the motor configuration. These are, from the stator point of view, different distribution, conductors' dimensions and number of effective turns, non-orthogonal magnetic axes windings and from the rotor point of view, asymmetrical rotor cage, variable reluctance, and permanent magnets effect. The time and space harmonics effect is ignored. Test data are compared with the computed data in order to observe how the simplifying assumptions affect the level of accuracy. The analytical prediction methods make possible torque computation according to the nature of the torque being computed, namely, induction, reluctance and excitation (permanent magnet). The results are available for quasi steady-state, steady-state (rated or synchronous speed) and dynamic analyses. All the developed

  16. Solar heating and cooling of mobile homes, Phase II. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsen, A.A.

    1976-12-01

    The specific objectives of the Phase II program were: (1) through system testing, confirm the feasibility of a solar heated and cooled mobile home; (2) update system performance analysis and provide solar heating and cooling computer model verification; (3) evaluate the performance of both an absorption and a Rankine air conditioning system; (4) perform a consumer demand analysis through field survey to ascertain the acceptance of solar energy into the mobile home market; and (5) while at field locations to conduct the consumer demand analysis, gather test data from various U.S. climatic zones. Results are presented and discussed. (WHK)

  17. Mobilities

    DEFF Research Database (Denmark)

    to social networks, personal identities, and our relationship to the built environment. The omnipresence of mobilities within everyday life, high politics, technology, and tourism (to mention but a few) all point to a key insight harnessed by the ‘mobilities turn’. Namely that mobilities is much more than......The world is on the move. This is a widespread understanding by many inhabitants of contemporary society across the Globe. But what does it actually mean? During over one decade the ‘mobilities turn’ within the social sciences have provided a new set of insights into the repercussions of mobilities...... and environmental degradation. The spaces and territories marked by mobilities as well as the sites marked by the bypassing of such are explored. Moreover, the architectural and technological dimensions to infrastructures and sites of mobilities will be included as well as the issues of power, social exclusion...

  18. Mobile clusters of single board computers: an option for providing resources to student projects and researchers.

    Science.gov (United States)

    Baun, Christian

    2016-01-01

    Clusters usually consist of servers, workstations or personal computers as nodes. But especially for academic purposes like student projects or scientific projects, the cost for purchase and operation can be a challenge. Single board computers cannot compete with the performance or energy-efficiency of higher-value systems, but they are an option to build inexpensive cluster systems. Because of the compact design and modest energy consumption, it is possible to build clusters of single board computers in a way that they are mobile and can be easily transported by the users. This paper describes the construction of such a cluster, useful applications and the performance of the single nodes. Furthermore, the clusters' performance and energy-efficiency is analyzed by executing the High Performance Linpack benchmark with a different number of nodes and different proportion of the systems total main memory utilized.

  19. Phase-field simulation of solidification in multicomponent alloys coupled with thermodynamic and diffusion mobility databases

    International Nuclear Information System (INIS)

    Zhang Ruijie; Jing Tao; Jie Wanqi; Liu Baicheng

    2006-01-01

    To simulate quantitatively the microstructural evolution in the solidification process of multicomponent alloys, we extend the phase-field model for binary alloys to multicomponent alloys with consideration of the solute interactions between different species. These interactions have a great influence not only on the phase equilibria but also on the solute diffusion behaviors. In the model, the interface region is assumed to be a mixture of solid and liquid with the same chemical potential, but with different compositions. The simulation presented is coupled with thermodynamic and diffusion mobility databases, which can accurately predict the phase equilibria and the solute diffusion transportation in the whole system. The phase equilibria in the interface and other thermodynamic quantities are obtained using Thermo-Calc through the TQ interface. As an example, two-dimensional computations for the dendritic growth in Al-Cu-Mg ternary alloy are performed. The quantitative solute distributions and diffusion matrix are obtained in both solid and liquid phases

  20. Consumers Intention to Use a Single Platform E-Payment System: A Study Among Malaysian Internet and Mobile Banking Users

    OpenAIRE

    LAI POEY CHIN; ZAINAL ARFFIN AHMAD

    2015-01-01

    This study seeks to explore Malaysian Internet and Mobile banking consumers’ in adopting a single platform E-payment system using TAM model. This research seeks to investigate whether convenience and design influence perceived ease of use and perceived usefulness. We also investigated the relationship between perceived ease of use, perceived usefulness and perceived risk with consumers’ intention to use one single platform that integrates card, internet and mobile. Respondents who used both t...

  1. Single-phase convective heat transfer in rod bundles

    International Nuclear Information System (INIS)

    Holloway, Mary V.; Beasley, Donald E.; Conner, Michael E.

    2008-01-01

    The convective heat transfer for turbulent flow through rod bundles representative of nuclear fuel rods used in pressurized water reactors is examined. The rod bundles consist of a square array of parallel rods that are held on a constant pitch by support grids spaced axially along the rod bundle. Split-vane pair support grids, which create swirling flow in the rod bundle, as well as disc and standard support grids are investigated. Single-phase convective heat transfer coefficients are measured for flow downstream of support grids in a rod bundle. The rods are heated using direct resistance heating, and a bulk axial flow of air is used to cool the rods in the rod bundle. Air is used as the working fluid instead of water to reduce the power required to heat the rod bundle. Results indicate heat transfer enhancement for up to 10 hydraulic diameters downstream of the support grids. A general correlation is developed to predict the heat transfer development downstream of support grids. In addition, circumferential variations in heat transfer coefficients result in hot streaks that develop on the rods downstream of split-vane pair support grids

  2. Single-phase convective heat transfer in rod bundles

    Energy Technology Data Exchange (ETDEWEB)

    Holloway, Mary V. [Mechanical Engineering Department, United States Naval Academy, 590 Holloway Rd., Annapolis, MD 21402 (United States)], E-mail: holloway@usna.edu; Beasley, Donald E. [Mechanical Engineering Department, Clemson University, Clemson, SC 29634 (United States); Conner, Michael E. [Westinghouse Nuclear Fuel, 5801 Bluff Road, Columbia, SC 29250 (United States)

    2008-04-15

    The convective heat transfer for turbulent flow through rod bundles representative of nuclear fuel rods used in pressurized water reactors is examined. The rod bundles consist of a square array of parallel rods that are held on a constant pitch by support grids spaced axially along the rod bundle. Split-vane pair support grids, which create swirling flow in the rod bundle, as well as disc and standard support grids are investigated. Single-phase convective heat transfer coefficients are measured for flow downstream of support grids in a rod bundle. The rods are heated using direct resistance heating, and a bulk axial flow of air is used to cool the rods in the rod bundle. Air is used as the working fluid instead of water to reduce the power required to heat the rod bundle. Results indicate heat transfer enhancement for up to 10 hydraulic diameters downstream of the support grids. A general correlation is developed to predict the heat transfer development downstream of support grids. In addition, circumferential variations in heat transfer coefficients result in hot streaks that develop on the rods downstream of split-vane pair support grids.

  3. Single particle detection: Phase control in submicron Hall sensors

    International Nuclear Information System (INIS)

    Di Michele, Lorenzo; Shelly, Connor; Gallop, John; Kazakova, Olga

    2010-01-01

    We present a phase-sensitive ac-dc Hall magnetometry method which allows a clear and reliable separation of real and parasitic magnetic signals of a very small magnitude. High-sensitivity semiconductor-based Hall crosses are generally accepted as a preferential solution for non-invasive detection of superparamagnetic nanobeads used in molecular biology, nanomedicine, and nanochemistry. However, detection of such small beads is often hindered by inductive pick-up and other spurious signals. The present work demonstrates an unambiguous experimental route for detection of small magnetic moments and provides a simple theoretical background for it. The reliability of the method has been tested for a variety of InSb Hall sensors in the range 600 nm-5 μm. Complete characterization of empty devices, involving Hall coefficients and noise measurements, has been performed and detection of a single FePt bead with diameter of 140 nm and magnetic moment of μ≅10 8 μ B has been achieved with a 600 nm-wide sensor.

  4. Self-assembled single-phase perovskite nanocomposite thin films.

    Science.gov (United States)

    Kim, Hyun-Suk; Bi, Lei; Paik, Hanjong; Yang, Dae-Jin; Park, Yun Chang; Dionne, Gerald F; Ross, Caroline A

    2010-02-10

    Thin films of perovskite-structured oxides with general formula ABO(3) have great potential in electronic devices because of their unique properties, which include the high dielectric constant of titanates, (1) high-T(C) superconductivity in cuprates, (2) and colossal magnetoresistance in manganites. (3) These properties are intimately dependent on, and can therefore be tailored by, the microstructure, orientation, and strain state of the film. Here, we demonstrate the growth of cubic Sr(Ti,Fe)O(3) (STF) films with an unusual self-assembled nanocomposite microstructure consisting of (100) and (110)-oriented crystals, both of which grow epitaxially with respect to the Si substrate and which are therefore homoepitaxial with each other. These structures differ from previously reported self-assembled oxide nanocomposites, which consist either of two different materials (4-7) or of single-phase distorted-cubic materials that exhibit two or more variants. (8-12) Moreover, an epitaxial nanocomposite SrTiO(3) overlayer can be grown on the STF, extending the range of compositions over which this microstructure can be formed. This offers the potential for the implementation of self-organized optical/ferromagnetic or ferromagnetic/ferroelectric hybrid nanostructures integrated on technologically important Si substrates with applications in magnetooptical or spintronic devices.

  5. Atomic mobility in the overheated amorphous GeTe compound for phase change memories

    International Nuclear Information System (INIS)

    Sosso, G.C.; Behler, J.; Bernasconi, M.

    2016-01-01

    Abstractauthoren Phase change memories rest on the ability of some chalcogenide alloys to undergo a fast and reversible transition between the crystalline and amorphous phases upon Joule heating. The fast crystallization is due to a high nucleation rate and a large crystal growth velocity which are actually possible thanks to the fragility of the supercooled liquid that allows for the persistence of a high atomic mobility at high supercooling where the thermodynamical driving force for crystallization is also high. Since crystallization in the devices occurs by rapidly heating the amorphous phase, hysteretic effects might arise with a different diffusion coefficient and viscosity on heating than on cooling. In this work, we have quantified these hysteretic effects in the phase change compound GeTe by means of molecular dynamics simulations. The atomic mobility in the overheated amorphous phase is lower than in supercooled liquid at the same temperature and the viscosity is consequently higher. Still, the simulations of the overheated amorphous phase reveal a breakdown of the Stokes-Einstein relation between the diffusion coefficient and the viscosity, similarly to what we found previously in the supercooled liquid. Evidences are provided that the breakdown is due to the emergence of dynamical heterogeneities at high supercooling. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Single DNA imaging and length quantification through a mobile phone microscope

    Science.gov (United States)

    Wei, Qingshan; Luo, Wei; Chiang, Samuel; Kappel, Tara; Mejia, Crystal; Tseng, Derek; Chan, Raymond Yan L.; Yan, Eddie; Qi, Hangfei; Shabbir, Faizan; Ozkan, Haydar; Feng, Steve; Ozcan, Aydogan

    2016-03-01

    The development of sensitive optical microscopy methods for the detection of single DNA molecules has become an active research area which cultivates various promising applications including point-of-care (POC) genetic testing and diagnostics. Direct visualization of individual DNA molecules usually relies on sophisticated optical microscopes that are mostly available in well-equipped laboratories. For POC DNA testing/detection, there is an increasing need for the development of new single DNA imaging and sensing methods that are field-portable, cost-effective, and accessible for diagnostic applications in resource-limited or field-settings. For this aim, we developed a mobile-phone integrated fluorescence microscopy platform that allows imaging and sizing of single DNA molecules that are stretched on a chip. This handheld device contains an opto-mechanical attachment integrated onto a smartphone camera module, which creates a high signal-to-noise ratio dark-field imaging condition by using an oblique illumination/excitation configuration. Using this device, we demonstrated imaging of individual linearly stretched λ DNA molecules (48 kilobase-pair, kbp) over 2 mm2 field-of-view. We further developed a robust computational algorithm and a smartphone app that allowed the users to quickly quantify the length of each DNA fragment imaged using this mobile interface. The cellphone based device was tested by five different DNA samples (5, 10, 20, 40, and 48 kbp), and a sizing accuracy of <1 kbp was demonstrated for DNA strands longer than 10 kbp. This mobile DNA imaging and sizing platform can be very useful for various diagnostic applications including the detection of disease-specific genes and quantification of copy-number-variations at POC settings.

  7. ESTABLISHED MODES AND STATIC CHARACTERISTICS OF THREE-PHASE ASYNCHRONOUS MOTOR POWERED WITH SINGLE PHASE NETWORK

    Directory of Open Access Journals (Sweden)

    V. S. Malyar

    2016-01-01

    Full Text Available A mathematical model is developed to study the operation of three-phase asynchronous motor with squirrel-cage rotor when the stator winding is powered from a single phase network. To create a rotating magnetic field one of the phases is fed through the capacitor. Due to the asymmetry of power feed not only transients, but the steady-state regimes are dynamic, so they are described by differential equations in any coordinate system. Their study cannot be carried out with sufficient adequacy on the basis of known equivalent circuits and require the use of dynamic parameters. In the mathematical model the state equations of the circuits of the stator and rotor are composed in the stationary three phase coordinate system. Calculation of the established mode is performed by solving the boundary problem that makes it possible to obtain the coordinate dependences over the period, without calculation of the transient process. In order to perform it, the original nonlinear differential equations are algebraized by approximating the variables with the use of cubic splines. The resulting nonlinear system of algebraic equations is a discrete analogue of the initial system of differential equations. It is solved by parameter continuation method. To calculate the static characteristics as a function of a certain variable, the system is analytically differentiated, and then numerically integrated over this variable. In the process of integration, Newton's refinement is performed at each step or at every few steps, making it possible to implement the integration in just a few steps using Euler's method. Jacobi matrices in both cases are the same. To account for the current displacement in the rods of the squirrel-cage rotor, each of them, along with the squirrel-cage rings, is divided in height into several elements. This results in several squirrel-cage rotor windings which are represented by three-phase windings with magnetic coupling between them.

  8. High p-Type Doping, Mobility, and Photocarrier Lifetime in Arsenic-Doped CdTe Single Crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kuciauskas, Darius [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Nagaoka, Akira [Kyoto University; University of Utah; McCoy, Jedidiah [Washington State University; Scarpulla, Michael A. [University of Utah

    2018-05-08

    Group-V element doping is promising for simultaneously maximizing the hole concentration and minority carrier lifetime in CdTe for thin film solar cells, but there are roadblocks concerning point defects including the possibility of self-compensation by AX metastability. Herein, we report on doping, lifetime, and mobility of CdTe single crystals doped with As between 10^16 and 10^20 cm-3 grown from the Cd solvent by the travelling heater method. Evidence consistent with AX instability as a major contributor to compensation in samples doped below 10^17 cm-3 is presented, while for higher-doped samples, precipitation of a second phase on planar structural defects is also observed and may explain spatial variation in properties such as lifetime. Rapid cooling after crystal growth increases doping efficiency and mobility for times up to 20-30 days at room temperature with the highest efficiencies observed close to 45% and a hole mobility of 70 cm2/Vs at room temperature. A doping limit in the low 10^17/cm3 range is observed for samples quenched at 200-300 degrees C/h. Bulk minority carrier lifetimes exceeding 20 ns are observed for samples doped near 10^16 cm-3 relaxed in the dark and for unintentionally doped samples, while a lifetime of nearly 5 ns is observed for 10^18 cm-3 As doping. These results help us to establish limits on properties expected for group-V doped CdTe polycrystalline thin films for use in photovoltaics.

  9. Single-phase and two phase bubbly flow in a T connection: theoretical and experimental study

    International Nuclear Information System (INIS)

    Hervieu, Eric

    1988-01-01

    The objective of this research thesis is to highlight the driving factors of the separation of phases of a bubbly flow in a T junction, and to develop a prediction model. In a first part, the author reports the rigorous formulation of equations averaged on the T volume. He shows that it's not possible to solve globally the problem with these equations. Then, he reports a bibliographical study on the modelling of a bubbly flow, and, based upon this study, highlights intrinsic characteristics of the flow, and explains its dynamic mechanisms. He reports the development of the theoretical model, and describes the experimental installation used to validate it. In the third part, he reports the study of the liquid-gas interaction, and presents the adopted approach: study of the behaviour of an isolated bubble within a single-phase flow. Experimentation is used to check theoretical predictions. Results are used to compute phase separation. The obtained results are again compared with experimental results to validate the global relevance of the model [fr

  10. Three-dimensional numerical modeling of turbulent single-phase and two-phase flow in curved pipes

    International Nuclear Information System (INIS)

    Xin, R.C.; Dong, Z.F.; Ebadian, M.A.

    1996-01-01

    In this study, three-dimensional single-phase and two-phase flows in curved pipes have been investigated numerically. Two different pipe configurations were computed. When the results of the single-phase flow simulation were compared with the experimental data, a fairly good agreement was achieved. A flow-developing process has been suggested in single-phase flow, in which the turbulence is stronger near the outer tube wall than near the inner tube wall. For two-phase flow, the Eulerian multiphase model was used to simulate the phase distribution of a three-dimensional gas-liquid bubble flow in curved pipe. The RNG/κ-ε turbulence model was used to determine the turbulence field. An inlet gas void fraction of 5 percent was simulated. The gas phase effects on the liquid phase flow velocity have been examined by comparing the results of single-phase flow and two-phase flow. The findings show that for the downward flow in the U bend, the gas concentrates at the inner portion of the cross section at φ = π/18 - π/6 in most cases. The results of the phase distribution simulation are compared to experimental observations qualitatively and topologically

  11. Single Electron Transistor Platform for Microgravity Proteomics, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase II program builds from the successful Phase I efforts to demonstrate that Quantum Logic Devices' nanoelectronic platform for biological detection could...

  12. Development of a Lunar-Phase Observation System Based on Augmented Reality and Mobile Learning Technologies

    Directory of Open Access Journals (Sweden)

    Wernhuar Tarng

    2016-01-01

    Full Text Available Observing the lunar phase requires long-term involvement, and it is often obstructed by bad weather or tall buildings. In this study, a lunar-phase observation system is developed using the augmented reality (AR technology and the sensor functions of GPS, electronic compass, and 3-axis accelerometer on mobile devices to help students observe and record lunar phases easily. By holding the mobile device towards the moon in the sky, the screen will show the virtual moon at the position of the real moon. The system allows the user to record the lunar phase, including its azimuth/elevation angles and the observation date and time. In addition, the system can shorten the learning process by setting different dates and times for observation, so it can solve the problem of being unable to observe and record lunar phases due to a bad weather or the moon appearing late in the night. Therefore, it is an effective tool for astronomy education in elementary and high schools. A teaching experiment has been conducted to analyze the learning effectiveness of the system and the results show that it is effective in learning the lunar concepts. The questionnaire results reveal that students considered the system easy to operate and it is useful in locating the moon and recording the lunar data.

  13. The chromatographic behavior of arsenic compounds on anion exchange columns with binary organic acids as mobile phases

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, J.; Goessler, W.; Kosmus, W. [Graz Univ. (Austria). Inst. fuer Analytische Chemie

    1998-03-01

    Identification and quantification of arsenic compounds was performed with high-performance liquid chromatography (HPLC) and flame atomic absorption spectrometry (FAAS) as element-specific detector. Arsenous acid, methylarsonic acid, dimethylarsinic acid, arsenic acid, arsenobetaine, and arsenocholine were separated on two anion-exchange columns (Synchropak Q 300 and PRP-X 100) with different binary organic acids as mobile phases. The influence of chromatographic parameters, such as pH and the concentration of the mobile phase were investigated. An unusual chromatographic behavior of arsenous acid was observed when tartaric acid was used as mobile phase. (orig.)

  14. European developments in single phase turbulence for innovative reactors

    Energy Technology Data Exchange (ETDEWEB)

    Roelofs, F., E-mail: roelofs@nrg.eu [NRG, Petten (Netherlands); Rohde, M. [DUT, Delft (Netherlands); and others

    2011-07-01

    Thermal-hydraulics is recognized as a key scientific subject in the development of different innovative nuclear reactor systems. From the thermal-hydraulic point of view, different innovative reactors are mainly characterized by their coolants (gas, water, liquid metals and molten salt). They result in specific behavior of flow and heat transfer, which requires specific models and advanced analysis tools. However, many common thermal-hydraulic issues are identified among various innovative nuclear systems. In Europe, such cross-cutting thermal-hydraulics topics are the motivation for the THINS (Thermal-Hydraulics of Innovative Nuclear Systems) project which is sponsored by the European Commission from 2010 to 2014. This paper describes the ongoing developments in an important part of this project devoted to single phase turbulence issues. To this respect, the two main issues have been identified: Non-unity Prandtl number turbulence. In case of liquid metals, molten salts or supercritical fluids, the commonly applied constant turbulent Prandtl number concept is not applicable and robust engineering turbulence models are needed. This paper will report on the progress achieved with respect to the development and validation of turbulence models available in commonly used engineering tools. The paper also reports about the supporting experiments and direct numerical simulations; and, Temperature fluctuations possibly leading to thermal fatigue in innovative reactors. The status is described of a fundamental experiment dealing with the mixing of different density gases in a rectangular channel, an experiment in a more complex geometry of a small mixing plenum using a supercritical fluid, and direct numerical simulations of conjugate heat transfer on temperature fluctuations in liquid metal. (author)

  15. European developments in single phase turbulence for innovative reactors

    International Nuclear Information System (INIS)

    Roelofs, F.; Rohde, M.

    2011-01-01

    Thermal-hydraulics is recognized as a key scientific subject in the development of different innovative nuclear reactor systems. From the thermal-hydraulic point of view, different innovative reactors are mainly characterized by their coolants (gas, water, liquid metals and molten salt). They result in specific behavior of flow and heat transfer, which requires specific models and advanced analysis tools. However, many common thermal-hydraulic issues are identified among various innovative nuclear systems. In Europe, such cross-cutting thermal-hydraulics topics are the motivation for the THINS (Thermal-Hydraulics of Innovative Nuclear Systems) project which is sponsored by the European Commission from 2010 to 2014. This paper describes the ongoing developments in an important part of this project devoted to single phase turbulence issues. To this respect, the two main issues have been identified: Non-unity Prandtl number turbulence. In case of liquid metals, molten salts or supercritical fluids, the commonly applied constant turbulent Prandtl number concept is not applicable and robust engineering turbulence models are needed. This paper will report on the progress achieved with respect to the development and validation of turbulence models available in commonly used engineering tools. The paper also reports about the supporting experiments and direct numerical simulations; and, Temperature fluctuations possibly leading to thermal fatigue in innovative reactors. The status is described of a fundamental experiment dealing with the mixing of different density gases in a rectangular channel, an experiment in a more complex geometry of a small mixing plenum using a supercritical fluid, and direct numerical simulations of conjugate heat transfer on temperature fluctuations in liquid metal. (author)

  16. Comprehensive Peptide Ion Structure Studies Using Ion Mobility Techniques: Part 3. Relating Solution-Phase to Gas-Phase Structures.

    Science.gov (United States)

    Kondalaji, Samaneh Ghassabi; Khakinejad, Mahdiar; Valentine, Stephen J

    2018-06-01

    Molecular dynamics (MD) simulations have been utilized to study peptide ion conformer establishment during the electrospray process. An explicit water model is used for nanodroplets containing a model peptide and hydronium ions. Simulations are conducted at 300 K for two different peptide ion charge configurations and for droplets containing varying numbers of hydronium ions. For all conditions, modeling has been performed until production of the gas-phase ions and the resultant conformers have been compared to proposed gas-phase structures. The latter species were obtained from previous studies in which in silico candidate structures were filtered according to ion mobility and hydrogen-deuterium exchange (HDX) reactivity matches. Results from the present study present three key findings namely (1) the evidence from ion production modeling supports previous structure refinement studies based on mobility and HDX reactivity matching, (2) the modeling of the electrospray process is significantly improved by utilizing initial droplets existing below but close to the calculated Rayleigh limit, and (3) peptide ions in the nanodroplets sample significantly different conformers than those in the bulk solution due to altered physicochemical properties of the solvent. Graphical Abstract ᅟ.

  17. Study of a new static mixer for two-phase and single-phase flows

    International Nuclear Information System (INIS)

    Foucrier, Michel

    1996-01-01

    The subject of this work is the study of OptimiX, a new static mixer, which is fully designed using an inverse method taking the final product features as input and based on the physical properties of the fluid to mix. The work began with the construction of an experimental loop which allowed us to qualify the mixer in two-phase and single-phase flow conditions. Next, a chemical method using a new test reaction and a micro-mixing model have been used to further characterise the mixer. This test reaction and the micro-mixing model have been developed by the 'Laboratoire des Sciences du Genie Chimique' of Nancy. The mixer OptimiX has proved to be an excellent device for both macro- and micro-mixing. The capability of this mixer to foster rapid reactions was also demonstrated. The well organised flow pattern of OptimiX, which results from its design, provides it with the unusual feature of being fully calculable. This work emphasizes the internal hydrodynamics of this mixer, justifies the universality of the design procedures, which validation is supported by the completed qualification work. (author) [fr

  18. STTR Phase 1 Final Technical Report for Project Entitled "Developing a Mobile Torrefaction Machine"

    Energy Technology Data Exchange (ETDEWEB)

    James, Joseph J. [President, ATP

    2014-03-11

    The goal of this project, sponsored by Agri-Tech Producers, LLC (ATP), the small business grantee, was to determine if the torrefaction technology, developed by North Carolina State University (NCSU), which ATP has licensed, could be feasibly deployed in a mobile unit. The study adds to the area investigated, by having ATP’s STTR Phase I team give thoughtful consideration to how to use NCSU’s technology in a mobile unit. The findings by ATP’s team were that NCSU’s technology would best perform in units 30’ by 80’ (See Spec Sheet for the Torre-Tech 5.0 Unit in the Appendix) and the technical effectiveness and economic feasibility investigation suggested that such units were not easily, efficiently or safely utilized in a forest or farm setting. (Note rendering of possible mobile system in the Appendix) Therefore, the findings by ATP’s team were that NCSU’s technology could not feasibly be deployed as a mobile unit.

  19. 78 FR 56875 - Tribal Mobility Fund Phase I Auction Rescheduled for December 19, 2013; Notice and Filing...

    Science.gov (United States)

    2013-09-16

    ... of comparing bids and measuring the performance of Tribal Mobility Fund Phase I support recipients..., EV-DO Rev A, UMTS/HSPA, HSPA+, WiMAX, and LTE. If the Mosaik data did not show such coverage, the...

  20. Power coordinated control method with frequency support capability for hybrid single/three-phase microgrid

    DEFF Research Database (Denmark)

    Zhou, Xiaoping; Chen, Yandong; Zhou, Leming

    2018-01-01

    storage unit (ESU) are added into hybrid single/three-phase microgrid, and a power coordinated control method with frequency support capability is proposed for hybrid single/three-phase microgrid in this study. PEU is connected with three single-phase microgrids to coordinate power exchange among three...... phases and provide frequency support for hybrid microgrid. Meanwhile, a power coordinated control method based on the droop control is proposed for PEU to alleviate three-phase power imbalance and reduce voltage fluctuation of hybrid microgrid. Besides, ESU is injected into the DC-link to buffer......Due to the intermittent output power of distributed generations (DGs) and the variability of loads, voltage fluctuation and three-phase power imbalance easily occur when hybrid single/three-phase microgrid operates in islanded mode. To address these issues, the power exchange unit (PEU) and energy...

  1. Computer simulation with TRNSYS for a mobile refrigeration system incorporating a phase change thermal storage unit

    International Nuclear Information System (INIS)

    Liu, Ming; Saman, Wasim; Bruno, Frank

    2014-01-01

    Highlights: • A mobile refrigeration system incorporating phase change thermal storage was simulated using TRNSYS. • A TRNSYS component of a phase change thermal storage unit was created and linked to other components from TRNSYS library. • The temperature in the refrigerated space can be predicted using this TRNSYS model under various conditions. • A mobile refrigeration system incorporating PCM and an off-peak electric driven refrigeration unit is feasible. • The phase change material with the lowest melting temperature should be selected. - Abstract: This paper presents a new TRNSYS model of a refrigeration system incorporating phase change material (PCM) for mobile transport. The PCTSU is charged by an off-vehicle refrigeration unit and the PCM provides cooling when discharging and the cooling released is utilized to cool down the refrigerated space. The advantage of this refrigeration system compared to a conventional system is that it consumes less energy and produces significantly lower greenhouse gas emissions. A refrigeration system for a typical refrigerated van is modelled and simulations are performed with climatic data from four different locations. The main components of the TRNSYS model are Type 88 (cooling load estimation) and Type 300 (new PCTSU component), accompanied by other additional components. The results show that in order to maintain the temperature of the products at −18 °C for 10 h, a total of 250 kg and 390 kg of PCM are required for no door opening and 20 door openings during the transportation, respectively. In addition, a parametric study is carried out to evaluate the effects of location, size of the refrigerated space, number of door openings and melting temperature of the PCM on the thermal performance

  2. Single phase and two phase erosion corrosion in broilers of gas-cooled reactors

    International Nuclear Information System (INIS)

    Harrison, G.S.; Fountain, M.J.

    1988-01-01

    Erosion-corrosion is a phenomenon causing metal wastage in a variety of locations in water and water-steam circuits throughout the power generation industry. Erosion-corrosion can occur in a number of regions of the once-through boiler designs used in the later Magnox and AGR type of gas cooled nuclear reactor. This paper will consider two cases of erosion-corrosion damage (single and two phase) in once through boilers of gas cooled reactors and will describe the solutions that have been developed. The single phase problem is associated with erosion-corrosion damage of mild steel downstream of a boiler inlet flow control orifice. With metal loss rates of up to 1 mm/year at 150 deg. C and pH in the range 9.0-9.4 it was found that 5 μg/kg oxygen was sufficient to reduce erosion-corrosion rates to less than 0.02 mm/year. A combined oxygen-ammonia-hydrazine feedwater regime was developed and validated to eliminate oxygen carryover and hence give protection from stress corrosion in the austenitic section of the AGR once through boiler whilst still providing erosion-corrosion control. Two phase erosion-corrosion tube failures have occurred in the evaporator of the mild steel once through boilers of the later Magnox reactors operating at pressures in the range 35-40 bar. Rig studies have shown that amines dosed in the feedwater can provide a significant reduction in metal loss rates and a tube lifetime assessment technique has been developed to predict potential tube failure profiles in a fully operational boiler. The solutions identified for both problems have been successfully implemented and the experience obtained following implementation including any problems or other benefits arising from the introduction of the new regimes will be presented. Methods for monitoring and evaluating the efficiency of the solutions have been developed and the results from these exercises will also be discussed. Consideration will also be given to the similarities in the metal loss

  3. Single phase and two phase erosion corrosion in broilers of gas-cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, G S; Fountain, M J [Operational Engineering Division (Northern Area), Central Electricity Generating Board, Manchester (United Kingdom)

    1988-07-01

    Erosion-corrosion is a phenomenon causing metal wastage in a variety of locations in water and water-steam circuits throughout the power generation industry. Erosion-corrosion can occur in a number of regions of the once-through boiler designs used in the later Magnox and AGR type of gas cooled nuclear reactor. This paper will consider two cases of erosion-corrosion damage (single and two phase) in once through boilers of gas cooled reactors and will describe the solutions that have been developed. The single phase problem is associated with erosion-corrosion damage of mild steel downstream of a boiler inlet flow control orifice. With metal loss rates of up to 1 mm/year at 150 deg. C and pH in the range 9.0-9.4 it was found that 5 {mu}g/kg oxygen was sufficient to reduce erosion-corrosion rates to less than 0.02 mm/year. A combined oxygen-ammonia-hydrazine feedwater regime was developed and validated to eliminate oxygen carryover and hence give protection from stress corrosion in the austenitic section of the AGR once through boiler whilst still providing erosion-corrosion control. Two phase erosion-corrosion tube failures have occurred in the evaporator of the mild steel once through boilers of the later Magnox reactors operating at pressures in the range 35-40 bar. Rig studies have shown that amines dosed in the feedwater can provide a significant reduction in metal loss rates and a tube lifetime assessment technique has been developed to predict potential tube failure profiles in a fully operational boiler. The solutions identified for both problems have been successfully implemented and the experience obtained following implementation including any problems or other benefits arising from the introduction of the new regimes will be presented. Methods for monitoring and evaluating the efficiency of the solutions have been developed and the results from these exercises will also be discussed. Consideration will also be given to the similarities in the metal loss

  4. Superconducting phases of phosphorus hydride under pressure. Stabilization by mobile molecular hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Bi, Tiange; Miller, Daniel P.; Shamp, Andrew; Zurek, Eva [Department of Chemistry, State University of New York, Buffalo, NY (United States)

    2017-08-14

    At 80 GPa, phases with the PH{sub 2} stoichiometry, which are composed of simple cubic like phosphorus layers capped with hydrogen atoms and layers of H{sub 2} molecules, are predicted to be important species contributing to the recently observed superconductivity in compressed phosphine. The electron-phonon coupling in these phases results from the motions of the phosphorus atoms and the hydrogen atoms bound to them. The role of the mobile H{sub 2} layers is to decrease the Coulomb repulsion between the negatively charged hydrogen atoms capping the phosphorus layers. An insulating PH{sub 5} phase, the structure and bonding of which is reminiscent of diborane, is also predicted to be metastable at this pressure. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Power Based Phase-Locked Loop Under Adverse Conditions with Moving Average Filter for Single-Phase System

    Directory of Open Access Journals (Sweden)

    Menxi Xie

    2017-06-01

    Full Text Available High performance synchronization methord is citical for grid connected power converter. For single-phase system, power based phase-locked loop(pPLL uses a multiplier as phase detector(PD. As single-phase grid voltage is distorted, the phase error information contains ac disturbances oscillating at integer multiples of fundamental frequency which lead to detection error. This paper presents a new scheme based on moving average filter(MAF applied in-loop of pPLL. The signal characteristic of phase error is dissussed in detail. A predictive rule is adopted to compensate the delay induced by MAF, thus achieving fast dynamic response. In the case of frequency deviate from nomimal, estimated frequency is fed back to adjust the filter window length of MAF and buffer size of predictive rule. Simulation and experimental results show that proposed PLL achieves good performance under adverse grid conditions.

  6. Density induced crossover of electron mobilities in fluid C3 hydrocarbons; liquid phase behavior

    International Nuclear Information System (INIS)

    Gee, N.; Freeman, G.R.

    1980-01-01

    At n = 2 x 10 20 mol/cm 3 in the saturated vapors, the density normalized mobility (μn) of electrons equalled 2.4 x 10 23 mol/cmVs in cyclopropane, 1.5 x 10 23 in propane and 5.4 x 10 22 in propene. In cyclopropane and propene μn decreased due to quasilocalization at n > 4 x 10 20 mol/cm 3 . In propane quasilocalization occurred at n > 8 x 10 20 mol/cm 3 . The more extensive quasilocalization in cyclopropane caused mobilities to be lower than those in propane at the same density when the densities were greater than 1.3 x 10 21 mol/cm 3 . In propylene, μn remained below those in the other compounds at all gas densities. In the liquid phase the mobilities were affected more by the changes of temperature than by those of density. The mobilities at a given temperature decreased in the order propane > propene > cyclopropane. It is curious that the electron traps are deeper in cyclopropane than in propene. The energies of both thermal and optical excitation of solvated electrons may be expressed by equations of the form E 0 = E(0) - aT over considerable ranges of temperature T. The thermal value of a/E(0) is 1.7 x 10 -3 K -1 in many hydrocarbons, estimated from the mobilities. The equivalent ratio of the optical parameters also equals 1.7 x 10 -3 K -1 in ethers and in ammonia. (author)

  7. new topology for single-phase, three-level, spwm vsi with lc filter

    African Journals Online (AJOL)

    level PWM inverter. However, this is not the case with single-phase PWM inverters. In these days, the popular single-phase inverters adopt the full-bridge type using approximate sinusoidal modulation technique. The output voltage in them has two values: zero and pos- itive supply dc voltage levels in the positive half cycle.

  8. Torque Analysis With Saturation Effects for Non-Salient Single-Phase Permanent-Magnet Machines

    DEFF Research Database (Denmark)

    Lu, Kaiyuan; Ritchie, Ewen

    2011-01-01

    The effects of saturation on torque production for non-salient, single-phase, permanent-magnet machines are studied in this paper. An analytical torque equation is proposed to predict the instantaneous torque with saturation effects. Compared to the existing methods, it is computationally faster......-element results, and experimental results obtained on a prototype single-phase permanent-magnet machine....

  9. Large conditional single-photon cross-phase modulation

    Science.gov (United States)

    Hosseini, Mahdi; Duan, Yiheng; Vuletić, Vladan

    2016-01-01

    Deterministic optical quantum logic requires a nonlinear quantum process that alters the phase of a quantum optical state by π through interaction with only one photon. Here, we demonstrate a large conditional cross-phase modulation between a signal field, stored inside an atomic quantum memory, and a control photon that traverses a high-finesse optical cavity containing the atomic memory. This approach avoids fundamental limitations associated with multimode effects for traveling optical photons. We measure a conditional cross-phase shift of π/6 (and up to π/3 by postselection on photons that remain in the system longer than average) between the retrieved signal and control photons, and confirm deterministic entanglement between the signal and control modes by extracting a positive concurrence. By upgrading to a state-of-the-art cavity, our system can reach a coherent phase shift of π at low loss, enabling deterministic and universal photonic quantum logic. PMID:27519798

  10. the steady-state performance characteristics of single phase transfer

    African Journals Online (AJOL)

    2012-11-03

    Nov 3, 2012 ... field (SPTF) machine operating in the asynchronous mode from which the performance charac- teristics could be ... motor from a poly-phase induction motor by discon- necting one of its .... tating magnetic field. The pulsating ...

  11. 1.26 Single Frequency Fiber Laser, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for the development of an innovative compact, high power, and extremely reliable 1.26 micron Ho-doped single frequency fiber laser. The proposed...

  12. 1.26 Single Frequency Fiber Laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for the development of an innovative compact, high power, and extremely reliable 1.26 micron Ho-doped single frequency fiber laser. The proposed...

  13. Single Molecule Scanning of DNA Radiation Oxidative Damage, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal will develop an assay to map genomic DNA, at the single molecule level and in a nanodevice, for oxidative DNA damage arising from radiation exposure;...

  14. Natural circulation in single-phase and two-phase flow

    International Nuclear Information System (INIS)

    Cheung, F.B.; El-Genk, M.S.

    1989-01-01

    Natural circulation usually arises in a closed loop between a heat source and a heat sink were the fluid motion is driven by density difference. It may also occur in enclosures or cavities where the flow is induced primarily by temperature or concentration gradients within the fluid. The subject has recently received special attention by the heat transfer and nuclear reactor safety communities because of it importance to the areas of energy extraction, decay, heat removal in nuclear reactors, solar and geothermal heating, and cooling of electronic equipment. Although many new results and physical insights have been gained of the various natural circulation phenomena, a number of critical issues remain unresolved. These include, for example, transition from laminar to turbulent flow, buoyancy-induced turbulent flow modeling, change of flow regimes, flow field visualization, variable property effects, and flow instability. This symposium volume contains papers presented in the Natural Circulation in Single-Phase and Two-Phase Flow session at the 1989 Winter Annual Meeting of ASME, by authors from different countries including the United States, Japan, Canada, and Brazil. The papers deal with experimental and theoretical studies as well as state-of-the-art reviews, covering a broad spectrum of topics in natural circulation including: variable-conductance thermosyphons, microelectronic chip cooling, natural circulation in anisotropic porous media and in cavities, heat transfer in flat plat solar collectors, shutdown heat removal in fast reactors, cooling of light-water and heavy-water reactors. The breadth of papers contained in this volume clearly reflect the importance of the current interest in natural circulation as a means for passive cooling and heating

  15. Quantum discord and classical correlation signatures of mobility edges in one-dimensional aperiodic single-electron systems

    International Nuclear Information System (INIS)

    Gong, Longyan; Zhu, Hao; Zhao, Shengmei; Cheng, Weiwen; Sheng, Yubo

    2012-01-01

    We investigate numerically the quantum discord and the classical correlation in a one-dimensional slowly varying potential model and a one-dimensional Soukoulis–Economou ones, respectively. There are well-defined mobility edges in the slowly varying potential model, while there are discrepancies on mobility edges in the Soukoulis–Economou ones. In the slowly varying potential model, we find that extended and localized states can be distinguished by both the quantum discord and the classical correlation. There are sharp transitions in the quantum discord and the classical correlation at mobility edges. Based on these, we study “mobility edges” in the Soukoulis–Economou model using the quantum discord and the classical correlation, which gives another perspectives for these “mobility edges”. All these provide us good quantities, i.e., the quantum discord and the classical correlation, to reflect mobility edges in these one-dimensional aperiodic single-electron systems. Moreover, our studies propose a consistent interpretation of the discrepancies between previous numerical results about the Soukoulis–Economou model. -- Highlights: ► Quantum discord and classical correlation can signal mobility edges in two models. ► An interpretation for mobility edges in the Soukoulis–Economou model is proposed. ► Quantum discord and classical correlation can reflect well localization properties.

  16. The Political Mobilization of Serbian Communists in the First Phase of the "Antibureaucratic Revolution"

    Directory of Open Access Journals (Sweden)

    Vladimir Ribić

    2016-02-01

    Full Text Available This paper offers an analysis of concrete actions and legitimations, and also of the elements of the action- and legitimation basis of the Serbian communists’ political moblization conducted during the first phase of the so-called Antibureaucratic Revolution, which began in April 1987 with Slobodan Miloševi R’s speech in Kosovo Polje, and came to an end with the intra-party showdown at the Eighth Session of the Serbian Communist Party’s Central Committee in September of the same year. The paper also provides a reconstruction of the political context in which the mobilization was conducted.

  17. A new acetonitrile-free mobile phase method for LC-ELSD quantification of fructooligosaccharides in onion (Allium cepa L.).

    Science.gov (United States)

    Downes, Katherine; Terry, Leon A

    2010-06-30

    Onion soluble non-structural carbohydrates consist of fructose, glucose and sucrose plus fructooligosaccharides (FOS) with degrees of polymerisation (DP) in the range of 3-19. In onion, sugars and FOS are typically separated using liquid chromatography (LC) with acetonitrile (ACN) as a mobile phase. In recent times, however, the production of ACN has diminished due, in part, to the current worldwide economic recession. A study was therefore undertaken, to find an alternative LC method to quantify sugars and FOS from onion without the need for ACN. Two mobile phases were compared; the first taken from a paper by Vågen and Slimestad (2008) using ACN mobile phase, the second, a newly reported method using ethanol (EtOH). The EtOH mobile phase eluted similar concentrations of all FOS compared to the ACN mobile phase. In addition, limit of detection, limit of quantification and relative standard deviation values were sufficiently and consistently lower for all FOS using the EtOH mobile phase. The drawback of the EtOH mobile phase was mainly the inability to separate all individual sugar peaks, yet FOS could be successfully separated. However, using the same onion extract, a previously established LC method based on an isocratic water mobile phase could be used in a second run to separate sugars. Although the ACN mobile phase method is more convenient, in the current economic climate a method based on inexpensive and plentiful ethanol is a valid alternative and could potentially be applied to other fresh produce types. In addition to the mobile phase solvent, the effect of extraction solvents on sugar and FOS concentration was also investigated. EtOH is still widely used to extract sugars from onion although previous literature has concluded that MeOH is a superior solvent. For this reason, an EtOH-based extraction method was compared with a MeOH-based method to extract both sugars and FOS. The MeOH-based extraction method was more efficacious at extracting sugars and

  18. Gas-phase structure and fragmentation pathways of singly protonated peptides with N-terminal arginine.

    Science.gov (United States)

    Bythell, Benjamin J; Csonka, István P; Suhai, Sándor; Barofsky, Douglas F; Paizs, Béla

    2010-11-25

    The gas-phase structures and fragmentation pathways of the singly protonated peptide arginylglycylaspartic acid (RGD) are investigated by means of collision-induced-dissociation (CID) and detailed molecular mechanics and density functional theory (DFT) calculations. It is demonstrated that despite the ionizing proton being strongly sequestered at the guanidine group, protonated RGD can easily be fragmented on charge directed fragmentation pathways. This is due to facile mobilization of the C-terminal or aspartic acid COOH protons thereby generating salt-bridge (SB) stabilized structures. These SB intermediates can directly fragment to generate b(2) ions or facilely rearrange to form anhydrides from which both b(2) and b(2)+H(2)O fragments can be formed. The salt-bridge stabilized and anhydride transition structures (TSs) necessary to form b(2) and b(2)+H(2)O are much lower in energy than their traditional charge solvated counterparts. These mechanisms provide compelling evidence of the role of SB and anhydride structures in protonated peptide fragmentation which complements and supports our recent findings for tryptic systems (Bythell, B. J.; Suhai, S.; Somogyi, A.; Paizs, B. J. Am. Chem. Soc. 2009, 131, 14057-14065.). In addition to these findings we also report on the mechanisms for the formation of the b(1) ion, neutral loss (H(2)O, NH(3), guanidine) fragment ions, and the d(3) ion.

  19. 16 channel WDM regeneration in a single phase-sensitive amplifier through optical Fourier transformation

    DEFF Research Database (Denmark)

    Guan, Pengyu; Da Ros, Francesco; Lillieholm, Mads

    2016-01-01

    We demonstrate simultaneous phase regeneration of 16-WDM DPSK channels using optical Fourier transformation and a single phase-sensitive amplifier. The BERs of 16-WDM×10-Gbit/s phase noise degraded DPSK signals are improved by 0.4-1.3 orders of magnitude...

  20. Analysis and MPPT control of a wind-driven three-phase induction generator feeding single-phase utility grid

    Directory of Open Access Journals (Sweden)

    Krishnan Arthishri

    2017-05-01

    Full Text Available In this study, a three-phase diode bridge rectifier and a single-phase voltage source inverter topology has been proposed for feeding single-phase utility grid employing a three-phase induction generator fed from wind energy. A self-excited induction generator configuration has been chosen for wide speed operation of wind turbine system, which gives the scope for extracting maximum power available in the wind. In addition to maximum power point tracking (MPPT, the generator can be loaded to its rated capacity for feeding single-phase utility grid using a three-phase induction machine, whereas it is not possible with existing configurations because of the absence of power converters. For the proposed system, MPPT algorithm has been devised by continuously monitoring the grid current and a proportional resonant controller has been employed for grid synchronisation of voltage source inverter with single-phase grid. A MATLAB/Simulink model of the proposed system has been developed to ascertain its successful working by predetermining the overall performance characteristics. The present proposal has also been tested with sag, swell and distortion in the grid voltage. The control strategy has been implemented using field programmable gate array (FPGA controller with modularised programming approach. The efficacy of the system has been demonstrated with the results obtained from an experimental set-up in the laboratory.

  1. Circadian phase resetting via single and multiple control targets.

    Directory of Open Access Journals (Sweden)

    Neda Bagheri

    2008-07-01

    Full Text Available Circadian entrainment is necessary for rhythmic physiological functions to be appropriately timed over the 24-hour day. Disruption of circadian rhythms has been associated with sleep and neuro-behavioral impairments as well as cancer. To date, light is widely accepted to be the most powerful circadian synchronizer, motivating its use as a key control input for phase resetting. Through sensitivity analysis, we identify additional control targets whose individual and simultaneous manipulation (via a model predictive control algorithm out-perform the open-loop light-based phase recovery dynamics by nearly 3-fold. We further demonstrate the robustness of phase resetting by synchronizing short- and long-period mutant phenotypes to the 24-hour environment; the control algorithm is robust in the presence of model mismatch. These studies prove the efficacy and immediate application of model predictive control in experimental studies and medicine. In particular, maintaining proper circadian regulation may significantly decrease the chance of acquiring chronic illness.

  2. Liquid phase separation of proteins based on electrophoretic effects in an electrospray setup during sample introduction into a gas-phase electrophoretic mobility molecular analyzer (CE–GEMMA/CE–ES–DMA)

    Science.gov (United States)

    Weiss, Victor U.; Kerul, Lukas; Kallinger, Peter; Szymanski, Wladyslaw W.; Marchetti-Deschmann, Martina; Allmaier, Günter

    2014-01-01

    Nanoparticle characterization is gaining importance in food technology, biotechnology, medicine, and pharmaceutical industry. An instrument to determine particle electrophoretic mobility (EM) diameters in the single-digit to double-digit nanometer range receiving increased attention is the gas-phase electrophoretic mobility molecular analyzer (GEMMA) separating electrophoretically single charged analytes in the gas-phase at ambient pressure. A fused-silica capillary is used for analyte transfer to the gas-phase by means of a nano electrospray (ES) unit. The potential of this capillary to separate analytes electrophoretically in the liquid phase due to different mobilities is, at measurement conditions recommended by the manufacturer, eliminated due to elevated pressure applied for sample introduction. Measurements are carried out upon constant feeding of analytes to the system. Under these conditions, aggregate formation is observed for samples including high amounts of non-volatile components or complex samples. This makes the EM determination of individual species sometimes difficult, if not impossible. With the current study we demonstrate that liquid phase electrophoretic separation of proteins (as exemplary analytes) occurs in the capillary (capillary zone electrophoresis, CE) of the nano ES unit of the GEMMA. This finding was consecutively applied for on-line desalting allowing EM diameter determination of analytes despite a high salt concentration within samples. The present study is to our knowledge the first report on the use of the GEMMA to determine EM diameters of analytes solubilized in the ES incompatible electrolyte solutions by the intended use of electrophoresis (in the liquid phase) during sample delivery. Results demonstrate the proof of concept of such an approach and additionally illustrate the high potential of a future on-line coupling of a capillary electrophoresis to a GEMMA instrument. PMID:25109866

  3. Theoretical modelling and experimental investigation of single-phase and two-phase flow division at a tee-junction

    International Nuclear Information System (INIS)

    Lemonnier, H.; Hervieu, E.

    1991-01-01

    Phase separation in a tee-junction is modelled in the particular case of bubbly-flow. The model is based on a two-dimensional approach and hence, uses local equations. The first step consists in modelling the single-phase flow in the tee-junction. The free streamline theory is used to predict the flow of the continuous phase. The two recirculation zones which are presented in this case are predicted by the model. The second step consists in predicting the gas bubble paths as a result of the actions of the single-phase flow. Finally, the trajectories of gas bubbles are used to predict the separation characteristics of the tee-junction. Each step of the modelling procedure has been carefully tested by an in-depth experimental investigation. Excellent quantitative agreement is obtained between experimental results and model predictions. Moreover, the phase separation phenomenon is found to be clearly described by the model. (orig.)

  4. Ultrafast photoinduced structure phase transition in antimony single crystals

    NARCIS (Netherlands)

    Fausti, Daniele; Misochko, Oleg V.; van Loosdrecht, Paul H. M.

    2009-01-01

    Picosecond Raman scattering is used to study the photoinduced ultrafast dynamics in Peierls distorted antimony. We find evidence for an ultrafast nonthermal reversible structural phase transition. Most surprisingly, we find evidence that this transition evolves toward a lower symmetry in contrast to

  5. Method of manufacture of single phase ceramic superconductors

    Science.gov (United States)

    Singh, Jitrenda P.; Poeppel, Roger B.; Goretta, Kenneth C.; Chen, Nan

    1995-01-01

    A ceramic superconductor is produced by close control of oxygen partial pressure during sintering of the material. The resulting microstructure of YBa.sub.2 Cu.sub.3 O.sub.x indicates that sintering kinetics are enhanced at reduced p(O.sub.2) and that because of second phase precipitates, grain growth is prevented. The density of specimens sintered at 910.degree. C. increased from 79 to 94% theoretical when p(O.sub.2) was decreased from 0.1 to 0.0001 MPa. The increase in density with decrease in p(O.sub.2) derives from enhanced sintering kinetics, due to increased defect concentration and decreased activation energy of the rate-controlling species undergoing diffusion. Sintering at 910.degree. C resulted in a fine-grain microstructure, with an average grain size of about 4 .mu.m. Post sintering annealing in a region of stability for the desired phase converts the second phases and limits grain growth. The method of pinning grain boundaries by small scale decompositive products and then annealing to convert its product to the desired phase can be used for other complex asides. Such a microstructure results in reduced microcracking, strengths as high as 230 MPa and high critical current density capacity.

  6. Photon Cascade from a Single Crystal Phase Nanowire Quantum Dot

    DEFF Research Database (Denmark)

    Bouwes Bavinck, Maaike; Jöns, Klaus D; Zieliński, Michal

    2016-01-01

    . We notice that the emission spectra consist often of two peaks close in energy, which we explain with a comprehensive theory showing that the symmetry of the system plays a crucial role for the hole levels forming hybridized orbitals. Our results state that crystal phase quantum dots have promising...

  7. Molecular dynamics simulations of single siloxane dendrimers: Molecular structure and intramolecular mobility of terminal groups

    Science.gov (United States)

    Kurbatov, A. O.; Balabaev, N. K.; Mazo, M. A.; Kramarenko, E. Yu.

    2018-01-01

    Molecular dynamics simulations of two types of isolated siloxane dendrimers of various generations (from the 2nd to the 8th) have been performed for temperatures ranging from 150 K to 600 K. The first type of dendrimer molecules has short spacers consisting of a single oxygen atom. In the dendrimers of the second type, spacers are longer and comprised of two oxygen atoms separated by a single silicon atom. A comparative analysis of molecular macroscopic parameters such as the gyration radius and the shape factor as well as atom distributions within dendrimer interior has been performed for varying generation number, temperature, and spacer length. It has been found that the short-spacer dendrimers of the 7th and 8th generations have a stressed central part with elongated bonds and deformed valence angles. Investigation of the time evolution of radial displacements of the terminal Si atoms has shown that a fraction of the Si groups have a reduced mobility. Therefore, rather long time trajectories (of the order of tens of nanoseconds) are required to study dendrimer intramolecular dynamics.

  8. An Isocratic Toxic Chemical-Free Mobile Phase HPLC-PDA Analysis of Malachite Green and Leuco-Malachite Green

    OpenAIRE

    Furusawa, Naoto

    2014-01-01

    This paper describes a reserved-phase high-performance liquid chromatographic (HPLC) method for detecting malachite green (MG) and leuco-malachite green (LMG) using an isocratic toxic organic solvent/reagent-free mobile phase. Chromatographic separations were performed an Inertsil® WP300 C4 with 0.02 mol/L octane sulfonic acid–ethanol mobile phase and a photodiode-array detector. The total run time was <5 min. The system suitability was well within the international acceptance criteria. A...

  9. An Isocratic Toxic Chemical-Free Mobile Phase HPLC-PDA Analysis of Malachite Green and Leuco-Malachite Green

    Directory of Open Access Journals (Sweden)

    Naoto Furusawa

    2014-05-01

    Full Text Available This paper describes a reserved-phase high-performance liquid chromatographic (HPLC method for detecting malachite green (MG and leuco-malachite green (LMG using an isocratic toxic organic solvent/reagent-free mobile phase. Chromatographic separations were performed an Inertsil® WP300 C4 with 0.02 mol/L octane sulfonic acid–ethanol mobile phase and a photodiode-array detector. The total run time was <5 min. The system suitability was well within the international acceptance criteria. A harmless method for simultaneously detecting MG and LMG was developed and may be further applied to the quantification in foods.

  10. Film boiling from spheres in single- and two-phase flow

    International Nuclear Information System (INIS)

    Liu, C.; Theofanous, T.G.; Yuen, W.W.

    1992-01-01

    Experimental data on film boiling heat transfer from single, inductively heated, spheres in single- and two-phase flow (saturated water and steam, respectively) are presented. In the single-phase-flow experiments water velocities ranged from 0.1 to 2.0 m/s; in the two-phase-flow experiments superficial water and steam velocities covered 0.1 to 0.6 m/s and 4 to 10 m/s, respectively. All experiments were run at atmospheric pressure and with sphere temperatures from 900C down to quenching. Limited interpretations of the single-phase- flow data are possible, but the two-phase-flow data are new and unique

  11. Hydrostatic-pressure induced phase transition of phonons in single-walled nanotubes

    International Nuclear Information System (INIS)

    Feng Peng; Meng Qingchao

    2009-01-01

    We study the effect of the hydrostatic pressure on the phonons in single-walled carbon nanotubes (SWNTs) in a magnetic field. We calculate the magnetic moments of the phonons using a functional integral technique, and find that the phonons in SWNTs undergo a pressure-induced phase transition from the paramagnetic phase to the diamagnetic phase under hydrostatic pressure 2 GPa. We explain the mechanism of generating this phase transition.

  12. Analysis of free-surface flows through energy considerations: Single-phase versus two-phase modeling.

    Science.gov (United States)

    Marrone, Salvatore; Colagrossi, Andrea; Di Mascio, Andrea; Le Touzé, David

    2016-05-01

    The study of energetic free-surface flows is challenging because of the large range of interface scales involved due to multiple fragmentations and reconnections of the air-water interface with the formation of drops and bubbles. Because of their complexity the investigation of such phenomena through numerical simulation largely increased during recent years. Actually, in the last decades different numerical models have been developed to study these flows, especially in the context of particle methods. In the latter a single-phase approximation is usually adopted to reduce the computational costs and the model complexity. While it is well known that the role of air largely affects the local flow evolution, it is still not clear whether this single-phase approximation is able to predict global flow features like the evolution of the global mechanical energy dissipation. The present work is dedicated to this topic through the study of a selected problem simulated with both single-phase and two-phase models. It is shown that, interestingly, even though flow evolutions are different, energy evolutions can be similar when including or not the presence of air. This is remarkable since, in the problem considered, with the two-phase model about half of the energy is lost in the air phase while in the one-phase model the energy is mainly dissipated by cavity collapses.

  13. High-quality single crystalline NiO with twin phases grown on sapphire substrate by metalorganic vapor phase epitaxy

    Directory of Open Access Journals (Sweden)

    Kazuo Uchida

    2012-12-01

    Full Text Available High-quality single crystalline twin phase NiO grown on sapphire substrates by metalorganic vapor phase epitaxy is reported. X-ray rocking curve analysis of NiO films grown at different temperatures indicates a minimum full width at half maximum of the cubic (111 diffraction peak of 0.107° for NiO film grown at as low as 550 °C. Detailed microstructural analysis by Φ scan X-ray diffraction and transmission electron microscopy reveal that the NiO film consists of large single crystalline domains with two different crystallographic orientations which are rotated relative to each other along the [111] axis by 60°. These single crystal domains are divided by the twin phase boundaries.

  14. Phase transitions and steady-state microstructures in a two-temperature lattice-gas model with mobile active impurities

    DEFF Research Database (Denmark)

    Henriksen, Jonas Rosager; Sabra, Mads Christian; Mouritsen, Ole G.

    2000-01-01

    The nonequilibrium, steady-state phase transitions and the structure of the different phases of a two-dimensional system with two thermodynamic temperatures are studied via a simple lattice-gas model with mobile active impurities ("hot/cold spots'') whose activity is controlled by an external drive...... on the temperatures, microstructured phases of both lamellar and droplet symmetry arise, described by a length scale that is determined by the characteristic temperature controlling the diffusive motion of the active impurities....

  15. Single-shot femtosecond-pulsed phase-shifting digital holography.

    Science.gov (United States)

    Kakue, Takashi; Itoh, Seiya; Xia, Peng; Tahara, Tatsuki; Awatsuji, Yasuhiro; Nishio, Kenzo; Ura, Shogo; Kubota, Toshihiro; Matoba, Osamu

    2012-08-27

    Parallel phase-shifting digital holography is capable of three-dimensional measurement of a dynamically moving object with a single-shot recording. In this letter, we demonstrated a parallel phase-shifting digital holography using a single femtosecond light pulse whose central wavelength and temporal duration were 800 nm and 96 fs, respectively. As an object, we set spark discharge in atmospheric pressure air induced by applying a high voltage to between two electrodes. The instantaneous change in phase caused by the spark discharge was clearly reconstructed. The reconstructed phase image shows the change of refractive index of air was -3.7 × 10(-4).

  16. Mobility and height detection of particle labels in an optical evanescent wave biosensor with single-label resolution

    NARCIS (Netherlands)

    van Ommering, K.; Somers, P.A.; Koets, M.; Schleipen, J.J.H.B.; IJzendoorn, van L.J.; Prins, M.W.J.

    2010-01-01

    Particle labels are used in biosensors to detect the presence and concentration of analyte molecules. In this paper we demonstrate an optical technique to measure the mobility and height of bound particle labels on a biosensor surface with single-label resolution. The technique is based on the

  17. Initial transformer sizing for single-phase residential load

    International Nuclear Information System (INIS)

    Schneider, K.C.; Hoad, R.F.

    1992-01-01

    The purchase of distribution transformers represents a significant capital investment per year for an electric utility. Choosing the correct thermal and economic size transformer can help control this investment. This paper describes a method for determining the correct economic size of distribution transformers using end-use appliance load profiles and the ANSI/IEEE Standard C57.91-1981 thermal model. Although applied only to single family and multifamily residential load in this paper, the method can be extended to other types of load such as commercial or industrial

  18. A Single Phase to Three Phase PFC Half-Bridge Converter Using BLDC Drive with SPWM Technique.

    OpenAIRE

    Srinu Duvvada; Manmadha Kumar B

    2014-01-01

    In this paper, a buck half-bridge DC-DC converter is used as a single-stage power factor correction (PFC) converter for feeding a voltage source inverter (VSI) based permanent magnet brushless DC motor (BLDC) drive. The front end of this PFC converter is a diode bridge rectifier (DBR) fed from single-phase AC mains. The BLDC is used to drive a compressor load of an air conditioner through a three-phase VSI fed from a controlled DC link voltage. The speed of the compressor is controlled to ach...

  19. A Fuzzy Logic Based Three phase Inverter with Single DC Source for Grid Connected PV System Employing Three Phase Transformer

    OpenAIRE

    Mani, venkatesan; Ramachandran, Rajeswari; N, Deverajan

    2016-01-01

    A fuzzy based three phase inverter with single DC source for grid connected photo voltaic (PV) system employing three phase transformer is presented in this paper. Space Vector Pulse Width Modulation (SVPWM) control scheme is effectively used to generate the appropriate switching sequences to the inverter switches. The intend of the fuzzy logic approach is to meet high quality output, fast response and high robustness. Finally Total Harmonics Distortion (THD) generated by the inverter is comp...

  20. A High Energy and High Efficiency Spectral Shaping Single Frequency Fiber Laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase I project proposes a tunable single frequency high energy fiber laser system for coherent Lidar systems for remote sensing. Current state-of-art...

  1. A High Energy and High Efficiency Spectral Shaping Single Frequency Fiber Laser, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase II project proposes a single frequency high energy fiber laser system for coherent Lidar systems for remote sensing. Current state-of-art...

  2. A Novel Model Predictive Control for Single-Phase Grid-Connected Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Zangeneh Bighash, Esmaeil; Sadeghzadeh, Seyed Mohammad; Ebrahimzadeh, Esmaeil

    2017-01-01

    Single-phase grid-connected inverters with LCL filter are widely used to connect photovoltaic systems to the utility grid. Among the existing control schemes, predictive control methods are faster and more accurate but also more complicated to implement. Recently, the Model Predictive Control (MPC......) algorithm for single-phase inverter has been presented, where the algorithm implementation is straightforward. In the MPC approach, all switching states are considered in each switching period to achieve the control objectives. However, since the number of switching states in single-phase inverters is small......, the inverter output current has a high Total Harmonic Distortions (THD). In order to reduce this, this paper presents an improved MPC for single-phase grid-connected inverters. In the proposed approach, the switching algorithm is changed and the number of the switching states is increased by means of virtual...

  3. Standard Specification for Sampling Single-Phase Geothermal Liquid or Steam for Purposes of Chemical Analysis

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1983-01-01

    1.1 This specification covers the basic requirements for equipment to be used for the collection of uncontaminated and representative samples from single-phase geothermal liquid or steam. Geopressured liquids are included. See Fig 1.

  4. High Power Compact Single-Frequency Volume Bragg Er-Doped Fiber Laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this NASA SBIR Phase I proposal is to develop the prototype of a compact single-frequency mode one longitudinal and one transverse mode laser...

  5. POD-Galerkin Model for Incompressible Single-Phase Flow in Porous Media

    KAUST Repository

    Wang, Yi; Yu, Bo; Sun, Shuyu

    2017-01-01

    Fast prediction modeling via proper orthogonal decomposition method combined with Galerkin projection is applied to incompressible single-phase fluid flow in porous media. Cases for different configurations of porous media, boundary conditions

  6. Single dose pharmacokinetics of fenspiride hydrochloride: phase I clinical trial.

    Science.gov (United States)

    Montes, B; Catalan, M; Roces, A; Jeanniot, J P; Honorato, J M

    1993-01-01

    The absolute bioavailability of fenspiride has been studied in twelve healthy volunteers. It was administered IV and orally in single doses of 80 mg fenspiride hydrochloride according to a randomised crossover pattern. Following IV administration, the plasma clearance of fenspiride was about 184 ml.min-1, and its apparent volume of distribution was moderately large (215 l). When given orally as a tablet, fenspiride exhibited fairly slow ab- sorption; the maximum plasma concentration (206 ng.ml-1) was achieved 6 h after administration. The absolute bioavailability was almost complete (90%). The tablet had slow release characteristics. The elimination half-life obtained from the plasma data was 14 to 16 h independent of the route of administration.

  7. Structure-retention and mobile phase-retention relationships for reversed-phase high-performance liquid chromatography of several hydroxythioxanthone derivatives in binary acetonitrile-water mixtures

    International Nuclear Information System (INIS)

    Amiri, Ali Asghar; Hemmateenejad, Bahram; Safavi, Afsaneh; Sharghi, Hashem; Beni, Ali Reza Salimi; Shamsipur, Mojtaba

    2007-01-01

    The reversed-phase high-performance liquid chromatographic (RP-HPLC) behavior of some newly synthesized hydroxythioxanthone derivatives using binary acetonitrile-water mixtures as mobile phase has been examined. First, the variation in the retention time of each molecule as a function of mobile phase properties was studied by Kamlet-Taft solvatochromic equations. Then, the influences of molecular structure of the hydroxythioxanthone derivatives on their retention time in various mobile phase mixtures were investigated by quantitative structure-property relationship (QSPR) analysis. Finally, a unified model containing both the molecular structure parameters and mobile phase properties was developed to describe the chromatographic behavior of the systems studied. Among the solvent properties, polarity/polarizability parameter (π * ) and hydrogen-bond basicity (β), and among the solute properties, the most positive local charge (MPC), the sum of positive charges on hydrogen atoms contributing in hydrogen bonding (SPCH) and lipophilicity index (log P) were identified as controlling factors in the RP-HPLC behavior of hydroxythioxanthone derivatives in actonitrile-water binary solvents

  8. Mobility function of a prosthetic knee joint with an automatic stance phase lock.

    Science.gov (United States)

    Andrysek, Jan; Klejman, Susan; Torres-Moreno, Ricardo; Heim, Winfried; Steinnagel, Bryan; Glasford, Shane

    2011-06-01

    There is a need for a prosthetic knee joint design that is technologically and functionally appropriate for use in developing countries. To develop and clinically evaluate a new type of stance phase controlled prosthetic knee joint that provides stance phase stability without inhibiting swing phase flexion. A crossover repeated measures study design comparing the new knee joint to the participant's conventional low- or high-end prosthetic knee joint. The new knee joint was fitted to fourteen individuals aged 15 to 67 years with unilateral lower limb amputations. Walk tests were performed to measure walking speed. Energy expenditure was estimated using the physiological cost index (PCI). Walking speeds with the new knee joint were on average 0.14 m/s faster than conventional low-end knees (p < 0.0001), but 0.07 m/s slower than conventional high-end prosthetic knees (p = 0.008). The PCI was similar across all three knee joint technologies (p = 0.276). Mobility function with the new knee joint, in terms of walking speed, was more closely matched to high-end than low-end prosthetic knee joints. Therefore, given its relatively simple design, the new stance phase control mechanism may offer a functional and cost effective solution for active transfemoral amputees. This paper describes a new type of prosthetic knee joint mechanism that is intended to be cost-effective while providing high-level stance phase function to active individuals with a transfemoral amputation. Initial clinical testing suggests that the new knee joint may have some functional advantages over existing technologies in this category.

  9. Optimized Charging Scheduling with Single Mobile Charger for Wireless Rechargeable Sensor Networks

    Directory of Open Access Journals (Sweden)

    Qihua Wang

    2017-11-01

    Full Text Available Due to the rapid development of wireless charging technology, the recharging issue in wireless rechargeable sensor network (WRSN has been a popular research problem in the past few years. The weakness of previous work is that charging route planning is not reasonable. In this work, a dynamic optimal scheduling scheme aiming to maximize the vacation time ratio of a single mobile changer for WRSN is proposed. In the proposed scheme, the wireless sensor network is divided into several sub-networks according to the initial topology of deployed sensor networks. After comprehensive analysis of energy states, working state and constraints for different sensor nodes in WRSN, we transform the optimized charging path problem of the whole network into the local optimization problem of the sub networks. The optimized charging path with respect to dynamic network topology in each sub-network is obtained by solving an optimization problem, and the lifetime of the deployed wireless sensor network can be prolonged. Simulation results show that the proposed scheme has good and reliable performance for a small wireless rechargeable sensor network.

  10. Design and implementation of a personal mobility of single spherical drive

    International Nuclear Information System (INIS)

    Hoshino, Tasuku; Yazawa, Miki; Naganuma, Ryota; Takada, Kotaro

    2016-01-01

    This paper deals with a personal electric vehicle driven by a single spherical wheel. Using an appropriate feedback control, this driving strategy realizes dynamic stability in all directions and the vehicle can always be kept upright on the road surface of variety of slopes. It also enables immediate mobility to all directions, unlike personal vehicles of two- wheel type. The spherical wheel is driven by omnidirectional wheels as usual; however, since the number and location of wheels have huge effect on the driving performance, the authors firstly analyze kinematics of omnidirectional wheels and sphere and derive new configuration to achieve maximum power. Based on the kinematic analysis, the equation of motion of the vehicle is derived via Lagrangian formulation. The full dynamic model including kinematic constraints is then derived. Using the full model, a stabilizing controller for driving is designed based on partial feedback linearization technique. The vehicle is constructed and tested with a human driver. The proposed configuration of omnidirectional wheels, the controller design model and the control scheme are examined in practice. Results of the experiments, including going over uphill road and uneven ground, show much better driving performance than authors’ previous prototype of the similar. (paper)

  11. A single exercise bout augments adenovirus-specific T-cell mobilization and function.

    Science.gov (United States)

    Kunz, Hawley E; Spielmann, Guillaume; Agha, Nadia H; O'Connor, Daniel P; Bollard, Catherine M; Simpson, Richard J

    2018-04-30

    Adoptive transfer of virus-specific T-cells (VSTs) effectively treats viral infections following allogeneic hematopoietic stem cell transplantation (alloHSCT), but logistical difficulties have limited widespread availability of VSTs as a post-transplant therapeutic. A single exercise bout mobilizes VSTs specific for latent herpesviruses (i.e. CMV and EBV) to peripheral blood and augments their ex vivo expansion. We investigated whether exercise exerts similar effects on T-cells specific for a NON-latent virus such as adenovirus, which is a major contributor to infection-related morbidity and mortality after alloHSCT. Thirty minutes of cycling exercise increased circulating adenovirus-specific T-cells 2.0-fold and augmented their ex vivo expansion by ~33% compared to rest without altering antigen and MHC-specific autologous target cell killing capabilities. We conclude that exercise is a simple and economical adjuvant to boost the isolation and manufacture of therapeutic VSTs specific to latent and non-latent viruses from healthy donors. Copyright © 2018. Published by Elsevier Inc.

  12. Reducing Electromagnetic Interference in a Grid Tied Single Phase Power Inverter

    Science.gov (United States)

    2016-09-01

    With the growing demand for a reliable electrical grid, backup power supplies and energy management systems are a necessity. Systems such as server...ELECTROMAGNETIC INTERFERENCE IN A GRID TIED SINGLE PHASE POWER INVERTER by Jason Hassan Valiani September 2016 Thesis Advisor: Giovanna Oriti...3. REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE REDUCING ELECTROMAGNETIC INTERFERENCE IN A GRID TIED SINGLE PHASE POWER

  13. System Model of Heat and Mass Transfer Process for Mobile Solvent Vapor Phase Drying Equipment

    Directory of Open Access Journals (Sweden)

    Shiwei Zhang

    2014-01-01

    Full Text Available The solvent vapor phase drying process is one of the most important processes during the production and maintenance for large oil-immersed power transformer. In this paper, the working principle, system composition, and technological process of mobile solvent vapor phase drying (MVPD equipment for transformer are introduced in detail. On the basis of necessary simplification and assumption for MVPD equipment and process, a heat and mass transfer mathematical model including 40 mathematical equations is established, which represents completely thermodynamics laws of phase change and transport process of solvent, water, and air in MVPD technological processes and describes in detail the quantitative relationship among important physical quantities such as temperature, pressure, and flux in key equipment units and process. Taking a practical field drying process of 500 KV/750 MVA power transformer as an example, the simulation calculation of a complete technological process is carried out by programming with MATLAB software and some relation curves of key process parameters changing with time are obtained such as body temperature, tank pressure, and water yield. The change trend of theoretical simulation results is very consistent with the actual production record data which verifies the correctness of mathematical model established.

  14. Searching for Next Single-Phase High-Entropy Alloy Compositions

    Directory of Open Access Journals (Sweden)

    David E. Alman

    2013-10-01

    Full Text Available There has been considerable technological interest in high-entropy alloys (HEAs since the initial publications on the topic appeared in 2004. However, only several of the alloys investigated are truly single-phase solid solution compositions. These include the FCC alloys CoCrFeNi and CoCrFeMnNi based on 3d transition metals elements and BCC alloys NbMoTaW, NbMoTaVW, and HfNbTaTiZr based on refractory metals. The search for new single-phase HEAs compositions has been hindered by a lack of an effective scientific strategy for alloy design. This report shows that the chemical interactions and atomic diffusivities predicted from ab initio molecular dynamics simulations which are closely related to primary crystallization during solidification can be used to assist in identifying single phase high-entropy solid solution compositions. Further, combining these simulations with phase diagram calculations via the CALPHAD method and inspection of existing phase diagrams is an effective strategy to accelerate the discovery of new single-phase HEAs. This methodology was used to predict new single-phase HEA compositions. These are FCC alloys comprised of CoFeMnNi, CuNiPdPt and CuNiPdPtRh, and HCP alloys of CoOsReRu.

  15. Coordinated single-phase control scheme for voltage unbalance reduction in low voltage network.

    Science.gov (United States)

    Pullaguram, Deepak; Mishra, Sukumar; Senroy, Nilanjan

    2017-08-13

    Low voltage (LV) distribution systems are typically unbalanced in nature due to unbalanced loading and unsymmetrical line configuration. This situation is further aggravated by single-phase power injections. A coordinated control scheme is proposed for single-phase sources, to reduce voltage unbalance. A consensus-based coordination is achieved using a multi-agent system, where each agent estimates the averaged global voltage and current magnitudes of individual phases in the LV network. These estimated values are used to modify the reference power of individual single-phase sources, to ensure system-wide balanced voltages and proper power sharing among sources connected to the same phase. Further, the high X / R ratio of the filter, used in the inverter of the single-phase source, enables control of reactive power, to minimize voltage unbalance locally. The proposed scheme is validated by simulating a LV distribution network with multiple single-phase sources subjected to various perturbations.This article is part of the themed issue 'Energy management: flexibility, risk and optimization'. © 2017 The Author(s).

  16. Decoupling single nanowire mobilities limited by surface scattering and bulk impurity scattering

    International Nuclear Information System (INIS)

    Khanal, D. R.; Levander, A. X.; Wu, J.; Yu, K. M.; Liliental-Weber, Z.; Walukiewicz, W.; Grandal, J.; Sanchez-Garcia, M. A.; Calleja, E.

    2011-01-01

    We demonstrate the isolation of two free carrier scattering mechanisms as a function of radial band bending in InN nanowires via universal mobility analysis, where effective carrier mobility is measured as a function of effective electric field in a nanowire field-effect transistor. Our results show that Coulomb scattering limits effective mobility at most effective fields, while surface roughness scattering only limits mobility under very high internal electric fields. High-energy α particle irradiation is used to vary the ionized donor concentration, and the observed decrease in mobility and increase in donor concentration are compared to Hall effect results of high-quality InN thin films. Our results show that for nanowires with relatively high doping and large diameters, controlling Coulomb scattering from ionized dopants should be given precedence over surface engineering when seeking to maximize nanowire mobility.

  17. Automatic testing in the integration phase of mobile work machine (TINAT) - MASIT31

    Energy Technology Data Exchange (ETDEWEB)

    Multanen, P.; Hyvoenen, M. (Tampere University of Technology, Department of Intelligent Hydraulics and Automation, Tampere (Finland)); Ellman, A. (Tampere University of Technology, Department of Mechanics and Design, Tampere (Finland)); Rantala, S.; Alanen, J. (VTT Technical Research Centre of Finland, Espoo (Finland))

    2008-07-01

    Abstract The performance and reliability of mobile work machines are significantly affected by control systems of machines and their characteristics. Currently the testing of control systems and verification of their properties is often carried out just in the integration phase of controls and mechanical structure of machine. This is very time consuming, requires a lot of test personnel and is not extensive enough. In TINAT project a test concept will be developed for the testing of entire control systems of work machines without real the mechanical structures of the machines by utilizing modelling and real-time hardware-in-the-loop simulation. The simulator system enables automatic generation of test scenarios and automatic analysis and reporting of test results. (orig.)

  18. Directed self-assembly of liquid crystalline blue-phases into ideal single-crystals

    Science.gov (United States)

    Martínez-González, Jose A.; Li, Xiao; Sadati, Monirosadat; Zhou, Ye; Zhang, Rui; Nealey, Paul F.; de Pablo, Juan J.

    2017-06-01

    Chiral nematic liquid crystals are known to form blue phases--liquid states of matter that exhibit ordered cubic arrangements of topological defects. Blue-phase specimens, however, are generally polycrystalline, consisting of randomly oriented domains that limit their performance in applications. A strategy that relies on nano-patterned substrates is presented here for preparation of stable, macroscopic single-crystal blue-phase materials. Different template designs are conceived to exert control over different planes of the blue-phase lattice orientation with respect to the underlying substrate. Experiments are then used to demonstrate that it is indeed possible to create stable single-crystal blue-phase domains with the desired orientation over large regions. These results provide a potential avenue to fully exploit the electro-optical properties of blue phases, which have been hindered by the existence of grain boundaries.

  19. Results of single borehole hydraulic testing in the Mizunami Underground Research Laboratory project. Phase 2

    International Nuclear Information System (INIS)

    Daimaru, Shuji; Takeuchi, Ryuji; Onoe, Hironori; Saegusa, Hiromitsu

    2012-09-01

    This report summarize the results of the single borehole hydraulic tests of 79 sections conducted as part of the Construction phase (Phase 2) in the Mizunami Underground Research Laboratory (MIU) Project. The details of each test (test interval depth, geology, etc.) as well as the interpreted hydraulic parameters and analytical method used are presented in this report. (author)

  20. Multi-scale Modeling of Compressible Single-phase Flow in Porous Media using Molecular Simulation

    KAUST Repository

    Saad, Ahmed Mohamed

    2016-01-01

    potential model that accounts for the molecular quadrupole moment of fluids with non-spherical molecules such as CO2. The potential model was used to simulate the thermodynamic equilibrium properties for single-phase and two-phase systems using the canonical

  1. Dynamics Assessment of Grid-Synchronization Algorithms for Single-Phase Grid-Connected Converters

    DEFF Research Database (Denmark)

    Han, Yang; Luo, Mingyu; Guerrero, Josep M.

    2015-01-01

    Several advanced phase-lock-loop (PLL) algorithms have been proposed for single-phase power electronic systems. Among these algorithms, the orthogonal signal generators (OSGs) are widely utilized to generate a set of in-quadrature signals, owing to its benefit of simple digital implementation and...

  2. Comparative Performance Evaluation of Orthogonal-Signal-Generators-Based Single-Phase PLL Algorithms

    DEFF Research Database (Denmark)

    Han, Yang; Luo, Mingyu; Zhao, Xin

    2016-01-01

    The orthogonal signal generator based phase-locked loops (OSG-PLLs) are among the most popular single-phase PLLs within the areas of power electronics and power systems, mainly because they are often easy to be implement and offer a robust performance against the grid disturbances. The main aim o...

  3. A combined single-multiphase flow formulation of the premixing phase using the level set method

    International Nuclear Information System (INIS)

    Leskovar, M.; Marn, J.

    1999-01-01

    The premixing phase of a steam explosion covers the interaction of the melt jet or droplets with the water prior to any steam explosion occurring. To get a better insight of the hydrodynamic processes during the premixing phase beside hot premixing experiments, where the water evaporation is significant, also cold isothermal premixing experiments are performed. The specialty of isothermal premixing experiments is that three phases are involved: the water, the air and the spheres phase, but only the spheres phase mixes with the other two phases whereas the water and air phases do not mix and remain separated by a free surface. Our idea therefore was to treat the isothermal premixing process with a combined single-multiphase flow model. In this combined model the water and air phase are treated as a single phase with discontinuous phase properties at the water air interface, whereas the spheres are treated as usually with a multiphase flow model, where the spheres represent the dispersed phase and the common water-air phase represents the continuous phase. The common water-air phase was described with the front capturing method based on the level set formulation. In the level set formulation, the boundary of two-fluid interfaces is modeled as the zero set of a smooth signed normal distance function defined on the entire physical domain. The boundary is then updated by solving a nonlinear equation of the Hamilton-Jacobi type on the whole domain. With this single-multiphase flow model the Queos isothermal premixing Q08 has been simulated. A numerical analysis using different treatments of the water-air interface (level set, high-resolution and upwind) has been performed for the incompressible and compressible case and the results were compared to experimental measurements.(author)

  4. Single Phase Transformer-less Buck-Boost Inverter with Zero Leakage Current for PV Systems

    DEFF Research Database (Denmark)

    Mostaan, Ali; Abdelhakim, Ahmed; N. Soltani, Mohsen

    2017-01-01

    In this paper, a novel single-stage single-phase transformer-less buck-boost inverter is proposed, in which a reduced number of passive components is used. The proposed inverter combines the conventional buck, boost, and buck-boost converters in one converter in order to obtain a sinusoidal output...

  5. Lyapunov-Based Control Scheme for Single-Phase Grid-Connected PV Central Inverters

    NARCIS (Netherlands)

    Meza, C.; Biel, D.; Jeltsema, D.; Scherpen, J. M. A.

    A Lyapunov-based control scheme for single-phase single-stage grid-connected photovoltaic central inverters is presented. Besides rendering the closed-loop system globally stable, the designed controller is able to deal with the system uncertainty that depends on the solar irradiance. A laboratory

  6. A Direct Maximum Power Point Tracking Method for Single-Phase Grid Connected PV Inverters

    DEFF Research Database (Denmark)

    EL Aamri, Faicel; Maker, Hattab; Sera, Dezso

    2018-01-01

    in dynamic conditions, especially in low irradiance when the measurement of signals becomes more sensitive to noise. The proposed MPPT is designed for single-phase single-stage grid-connected PV inverters, and is based on estimating the instantaneous PV power and voltage ripples, using second...

  7. Fully tunable 360° microwave photonic phase shifter based on a single semiconductor optical amplifier.

    Science.gov (United States)

    Sancho, Juan; Lloret, Juan; Gasulla, Ivana; Sales, Salvador; Capmany, José

    2011-08-29

    A fully tunable microwave photonic phase shifter involving a single semiconductor optical amplifier (SOA) is proposed and demonstrated. 360° microwave phase shift has been achieved by tuning the carrier wavelength and the optical input power injected in an SOA while properly profiting from the dispersion feature of a conveniently designed notch filter. It is shown that the optical filter can be advantageously employed to switch between positive and negative microwave phase shifts. Numerical calculations corroborate the experimental results showing an excellent agreement.

  8. Fabrication of single phase 2D homologous perovskite microplates by mechanical exfoliation

    Science.gov (United States)

    Li, Junze; Wang, Jun; Zhang, Yingjun; Wang, Haizhen; Lin, Gaoming; Xiong, Xuan; Zhou, Weihang; Luo, Hongmei; Li, Dehui

    2018-04-01

    The two-dimensional (2D) Ruddlesden-Popper type perovskites have attracted intensive interest for their great environmental stability and various potential optoelectronic applications. Fundamental understanding of the photophysical and electronic properties of the 2D perovskites with pure single phase is essential for improving the performance of the optoelectronic devices and designing devices with new architectures. Investigating the optical and electronic properties of these materials with pure single phase is required to obtain pure single phase 2D perovskites. Here, we report on an alternative approach to fabricate (C4H9NH3)2(CH3NH3) n-1Pb n I3n+1 microplates with pure single n-number perovskite phase for n  >  2 by mechanical exfoliation. Micro-photoluminescence and absorption spectroscopy studies reveal that the as-synthesized 2D perovskite plates for n  >  2 are comprised by dominant n-number phase and small inclusions of hybrid perovskite phases with different n values, which is supported by excitation power dependent photoluminescence. By mechanical exfoliation method, 2D perovskite microplates with the thickness of around 20 nm are obtained, which surprisingly have single n-number perovskite phase for n  =  2-5. In addition, we have demonstrated that the exfoliated 2D perovskite microplates can be integrated with other 2D layered materials such as boron nitride, and are able to be transferred to prefabricated electrodes for photodetections. Our studies not only provide a strategy to prepare 2D perovskites with a single n-number perovskite phase allowing us to extract the basic optical and electronic parameters of pure phase perovskites, but also demonstrate the possibility to integrate the 2D perovskites with other 2D layered materials to extend the device’s functionalities.

  9. LIDAR forest inventory with single-tree, double- and single-phase procedures

    Science.gov (United States)

    Robert C. Parker; David L. Evans

    2009-01-01

    Light Detection and Ranging (LIDAR) data at 0.5- to 2-m postings were used with doublesample, stratified inventory procedures involving single-tree attribute relationships in mixed, natural, and planted species stands to yield sampling errors (one-half the confidence interval expressed as a percentage of the mean) ranging from ±2.1 percent to ±11.5...

  10. A single grain approach applied to modelling recrystallization kinetics in a single-phase metal

    NARCIS (Netherlands)

    Chen, S.P.; Zwaag, van der S.

    2004-01-01

    A comprehensive model for the recrystallization kinetics is proposed which incorporates both microstructure and the textural components in the deformed state. The model is based on the single-grain approach proposed previously. The influence of the as-deformed grain orientation, which affects the

  11. Performance Evaluation of Low/Zero Voltage Ride-Through Operations for Single-Stage Single-Phase Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Zhang, Zhen; Yang, Yongheng; Blaabjerg, Frede

    2017-01-01

    With the fast development of distributed power generations, stability and security have attracted extensive attention in the recent years. As a representative of clean energies, Photovoltaic (PV) systems have been installed extensively worldwide. This drives grid-connected requirements...... to be continuously updated. In current active grid requirements/codes, PV systems should be more intelligent in the considerations of the grid stability, reliability and fault protection. In this paper, two control strategies (i.e., the single-phase PQ control and power phase-angle control) are evaluated for grid...

  12. SINGLE PHASE ANALYTICAL MODELS FOR TERRY TURBINE NOZZLE

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Haihua; Zhang, Hongbin; Zou, Ling; O' Brien, James

    2016-11-01

    benchmarked with CFD simulations. The analytical models generally agree well with the experimental data and CFD simulations. The analytical models are suitable for implementation into a reactor system analysis code or severe accident code as part of mechanistic and dynamical models to understand the RCIC behaviors. The cases with two-phase flow at the turbine inlet will be pursued in future work.

  13. X-ray quality increasing system controlled by single-chip microcomputer in single phase fluoroscopy unit

    International Nuclear Information System (INIS)

    Wang Qiaolin; Gu Hongmei

    2004-01-01

    Objective: To decrease the amount of radiation that doctor and patient receives by increasing X-ray quality. Methods: Using Single-chip Microcomputer technology, test and modulate AC(Alternating Current) from high voltage generator by IGBT. X-ray tube generates X-rays only at high energy area. Thus the amount of radiation decreases. Results: The tube current decreases remarkably and the amount of radiation that doctor and patient receives decreases effectively. Conclusion: the system can effectively decrease the amount of radiation and is widely applicable to the upgrade of all kinds of single phase X-ray units. (authors)

  14. Similarity analysis and scaling criteria for LWRs under single-phase and two-phase natural circulation

    International Nuclear Information System (INIS)

    Ishii, M.; Kataoka, I.

    1983-03-01

    Scaling criteria for a natural circulation loop under single phase and two-phase flow conditions have been derived. For a single phase case the continuity, integral momentum, and energy equations in one-dimensional area average forms have been used. From this, the geometrical similarity groups, friction number, Richardson number, characteristic time constant ratio, Biot number, and heat source number are obtained. The Biot number involves the heat transfer coefficient which may cause some difficulties in simulating the turbulent flow regime. For a two-phase flow case, the similarity groups obtained from a perturbation analysis based on the one-dimensional drift-flux model have been used. The physical significance of the phase change number, subcooling number, drift-flux number, friction number are discussed and conditions imposed by these groups are evaluated. In the two-phase flow case, the critical heat flux is one of the most important transients which should be simulated in a scale model. The above results are applied to the LOFT facility in case of a natural circulation simulation. Some preliminary conclusions on the feasibility of the facility have been obtained

  15. Similarity analysis and scaling criteria for LWRs under single-phase and two-phase natural circulation

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, M.; Kataoka, I.

    1983-03-01

    Scaling criteria for a natural circulation loop under single phase and two-phase flow conditions have been derived. For a single phase case the continuity, integral momentum, and energy equations in one-dimensional area average forms have been used. From this, the geometrical similarity groups, friction number, Richardson number, characteristic time constant ratio, Biot number, and heat source number are obtained. The Biot number involves the heat transfer coefficient which may cause some difficulties in simulating the turbulent flow regime. For a two-phase flow case, the similarity groups obtained from a perturbation analysis based on the one-dimensional drift-flux model have been used. The physical significance of the phase change number, subcooling number, drift-flux number, friction number are discussed and conditions imposed by these groups are evaluated. In the two-phase flow case, the critical heat flux is one of the most important transients which should be simulated in a scale model. The above results are applied to the LOFT facility in case of a natural circulation simulation. Some preliminary conclusions on the feasibility of the facility have been obtained.

  16. Benchmarking of Grid Fault Modes in Single-Phase Grid-Connected Photovoltaic Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang

    2013-01-01

    Pushed by the booming installations of singlephase photovoltaic (PV) systems, the grid demands regarding the integration of PV systems are expected to be modified. Hence, the future PV systems should become more active with functionalities of Low Voltage Ride-Through (LVRT) and grid support...... phase systems under grid faults. The intent of this paper is to present a benchmarking of grid fault modes that might come in future single-phase PV systems. In order to map future challenges, the relevant synchronization and control strategies are discussed. Some faulty modes are studied experimentally...... and provided at the end of this paper. It is concluded that there are extensive control possibilities in single-phase PV systems under grid faults. The Second Order General Integral based PLL technique might be the most promising candidate for future single-phase PV systems because of its fast adaptive...

  17. System and method for single-phase, single-stage grid-interactive inverter

    Science.gov (United States)

    Liu, Liming; Li, Hui

    2015-09-01

    The present invention provides for the integration of distributed renewable energy sources/storages utilizing a cascaded DC-AC inverter, thereby eliminating the need for a DC-DC converter. The ability to segment the energy sources and energy storages improves the maintenance capability and system reliability of the distributed generation system, as well as achieve wide range reactive power compensation. In the absence of a DC-DC converter, single stage energy conversion can be achieved to enhance energy conversion efficiency.

  18. Single-phase and two-phase gas-liquid turbulent mixing between subchannels in a simulated rod bundle

    International Nuclear Information System (INIS)

    Sadatomi, Michio; Kawahara, Akimaro; Sato, Yoshifusa; Tomino, Takayoshi.

    1996-01-01

    This study is concerned with turbulent mixing which is one of the three mechanisms of cross flows between subchannels in a nuclear fuel rod bundle. The channel used in this experiments was a vertical simulated rod bundle having two subchannels connected through 1 to 3 gaps between two rods and/or rod and channel wall. The number of the gaps was changed to investigate the effect of the number on the turbulent mixing. Turbulent mixing rates of air and water and fluctuations of pressure difference between the subchannels were measured for single-phase and two-phase gas-liquid flows under hydrodynamic equilibrium flow conditions. It has been confirmed that the turbulent mixing rate is affected strongly by the fluctuations especially for liquid phase in two-phase slug or churn flow. (author)

  19. A Small Ku-Band Polarization Tracking Active Phased Array for Mobile Satellite Communications

    Directory of Open Access Journals (Sweden)

    Wei Shi

    2013-01-01

    Full Text Available A compact polarization tracking active phased array for Ku-band mobile satellite signal reception is presented. In contrast with conventional mechanically tracking antennas, the approach presented here meets the requirements of beam tracking and polarization tracking simultaneously without any servo components. The two-layer stacked square patch fed by two probes is used as antenna element. The impedance bandwidth of 16% for the element covers the operating frequency range from 12.25 GHz to 12.75 GHz. In the presence of mutual coupling, the dimensional parameters for each element of the small 7 × 7 array are optimized during beam scanning and polarization tracking. The compact polarization tracking modules based on the low-temperature cofired ceramic (LTCC system-in-package (SiP technology are proposed. A small active phased array prototype with the size of 120 mm (length × 120 mm (width × 55 mm (height is developed. The measured polarization tracking patterns of the prototype are given. The polarization tracking beam can be steered in the elevation up to 50°. The gain of no less than 16.0 dBi and the aperture efficiency of more than 50% are obtained. The measured and simulated polarization tracking patterns agreed well.

  20. Optimising mobile phase composition, its flow-rate and column temperature in HPLC using taboo search.

    Science.gov (United States)

    Guillaume, Y C; Peyrin, E

    2000-03-06

    A chemometric methodology is proposed to study the separation of seven p-hydroxybenzoic esters in reversed phase liquid chromatography (RPLC). Fifteen experiments were found to be necessary to find a mathematical model which linked a novel chromatographic response function (CRF) with the column temperature, the water fraction in the mobile phase and its flow rate. The CRF optimum was determined using a new algorithm based on Glover's taboo search (TS). A flow-rate of 0.9 ml min(-1) with a water fraction of 0.64 in the ACN-water mixture and a column temperature of 10 degrees C gave the most efficient separation conditions. The usefulness of TS was compared with the pure random search (PRS) and simplex search (SS). As demonstrated by calculations, the algorithm avoids entrapment in local minima and continues the search to give a near-optimal final solution. Unlike other methods of global optimisation, this procedure is generally applicable, easy to implement, derivative free, conceptually simple and could be used in the future for much more complex optimisation problems.

  1. Ratchet Effects, Negative Mobility, and Phase Locking for Skyrmions on Periodic Substrates

    Science.gov (United States)

    Reichhardt, Charles; Ray, Dipanjan; Olson Reichhardt, Cynthia

    We examine the dynamics of skyrmions interacting with 1D and 2D periodic substrates in the presence of dc and ac drives. We find that the Magnus term strongly affects the skyrmion dynamics and that new kinds of phenomena can occur which are absent for overdamped ac and dc driven particles interacting with similar substrates. We show that it is possible to realize a Magnus induced ratchet for skyrmions interacting with an asymmetric potential, where the application of an ac drive can produce quantized dc motion of the skyrmions even when the ac force is perpendicular to the substrate asymmetry direction. For symmetric substrates it is also possible to achieve a negative mobility effect where the net skyrmion motion runs counter to an applied dc drive. Here, as a function of increasing dc drive, the velocity-force curves show a series of locking phases that have different features from the classic Shapiro steps found in overdamped systems. In the phase locking and ratcheting states, the skyrmions undergo intricate 2D orbits induced by the Magnus term.

  2. Migration and clinical outcome of mobile-bearing versus fixed-bearing single-radius total knee arthroplasty.

    Science.gov (United States)

    Van Hamersveld, Koen T; Marang-Van De Mheen, Perla J; Van Der Heide, Huub J L; Van Der Linden-Van Der Zwaag, Henrica M J; Valstar, Edward R; Nelissen, Rob G H H

    2018-04-01

    Background and purpose - Mobile-bearing total knee prostheses (TKPs) were developed in the 1970s in an attempt to increase function and improve implant longevity. However, modern fixed-bearing designs like the single-radius TKP may provide similar advantages. We compared tibial component migration measured with radiostereometric analysis (RSA) and clinical outcome of otherwise similarly designed cemented fixed-bearing and mobile-bearing single-radius TKPs. Patients and methods - RSA measurements and clinical scores were assessed in 46 randomized patients at baseline, 6 months, 1 year, and annually thereafter up to 6 years postoperatively. A linear mixed-effects model was used to analyze the repeated measurements. Results - Both groups showed comparable migration (p = 0.3), with a mean migration at 6-year follow-up of 0.90 mm (95% CI 0.49-1.41) for the fixed-bearing group compared with 1.22 mm (95% CI 0.75-1.80) for the mobile-bearing group. Clinical outcomes were similar between groups. 1 fixed-bearing knee was revised for aseptic loosening after 6 years and 2 knees (1 in each group) were revised for late infection. 2 knees (1 in each group) were suspected for loosening due to excessive migration. Another mobile-bearing knee was revised after an insert dislocation due to failure of the locking mechanism 6 weeks postoperatively, after which study inclusion was preliminary terminated. Interpretation - Fixed-bearing and mobile-bearing single-radius TKPs showed similar migration. The latter may, however, expose patients to more complex surgical techniques and risks such as insert dislocations inherent to this rotating-platform design.

  3. Development of an atomic mobility database for liquid phase in multicomponent Al alloys. Focusing on binary systems

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shaoqing; Du, Yong; Zhang, Lijun [Central South Univ., Changsha, Hunan (China). State Key Laboratory of Powder Metallurgy; Liu, Dandan [Central South Univ., Changsha, Hunan (China). State Key Laboratory of Powder Metallurgy; Central South Univ., Changsha, Hunan (China). School of Materials Science and Engineering; Chen, Qing; Engstroem, Anders [Thermo-Calc Software AB, Stockholm (Sweden)

    2013-08-15

    An atomic mobility database for binary liquid phase in multicomponent Al-Cu-Fe-Mg-Mn-Ni-Si-Zn alloys was established based on critically reviewed experimental and theoretical diffusion data by using DICTRA (Diffusion Controlled TRAnsformation) software. The impurity diffusivities of the elements with limited experimental data are obtained by means of the least-squares method and semi-empirical correlations. Comprehensive comparisons between the calculated and measured diffusivities indicate that most of the reported diffusivities can be well reproduced by the currently obtained atomic mobilities. The reliability of this diffusivity database is further validated by comparing the simulated concentration profiles with the measured ones, as well as the measured main inter-diffusion coefficients of liquid Al-Cu-Zn alloys with the extrapolated ones from the present binary atomic mobility database. The approach is of general validity and applicable to establish mobility databases of other liquid alloys. (orig.)

  4. Criterion for traffic phases in single vehicle data and empirical test of a microscopic three-phase traffic theory

    International Nuclear Information System (INIS)

    Kerner, Boris S; Klenov, Sergey L; Hiller, Andreas

    2006-01-01

    Based on empirical and numerical microscopic analyses, the physical nature of a qualitatively different behaviour of the wide moving jam phase in comparison with the synchronized flow phase-microscopic traffic flow interruption within the wide moving jam phase-is found. A microscopic criterion for distinguishing the synchronized flow and wide moving jam phases in single vehicle data measured at a single freeway location is presented. Based on this criterion, empirical microscopic classification of different local congested traffic states is performed. Simulations made show that the microscopic criterion and macroscopic spatiotemporal objective criteria lead to the same identification of the synchronized flow and wide moving jam phases in congested traffic. Microscopic models in the context of three-phase traffic theory have been tested based on the microscopic criterion for the phases in congested traffic. It is found that microscopic three-phase traffic models can explain both microscopic and macroscopic empirical congested pattern features. It is obtained that microscopic frequency distributions for vehicle speed difference as well as fundamental diagrams and speed correlation functions can depend on the spatial co-ordinate considerably. It turns out that microscopic optimal velocity (OV) functions and time headway distributions are not necessarily qualitatively different, even if local congested traffic states are qualitatively different. The reason for this is that important spatiotemporal features of congested traffic patterns are lost in these as well as in many other macroscopic and microscopic traffic characteristics, which are widely used as the empirical basis for a test of traffic flow models, specifically, cellular automata traffic flow models

  5. Single particle analysis based on Zernike phase contrast transmission electron microscopy.

    Science.gov (United States)

    Danev, Radostin; Nagayama, Kuniaki

    2008-02-01

    We present the first application of Zernike phase-contrast transmission electron microscopy to single-particle 3D reconstruction of a protein, using GroEL chaperonin as the test specimen. We evaluated the performance of the technique by comparing 3D models derived from Zernike phase contrast imaging, with models from conventional underfocus phase contrast imaging. The same resolution, about 12A, was achieved by both imaging methods. The reconstruction based on Zernike phase contrast data required about 30% fewer particles. The advantages and prospects of each technique are discussed.

  6. Single-phase ProtoDUNE, the Prototype of a Single-Phase Liquid Argon TPC for DUNE at the CERN Neutrino Platform

    CERN Document Server

    Cavanna, F; Touramanis, C

    2017-01-01

    ProtoDUNE-SP is the single-phase DUNE Far Detector prototype that is under construction and will be operated at the CERN Neutrino Platform (NP) starting in 2018. It was proposed to the CERN SPSC in June 2015 (SPSC-P-351) and was approved in December 2015 as experiment NP04 (ProtoDUNE). ProtoDUNE-SP, a crucial part of the DUNE effort towards the construction of the first DUNE 10-kt fiducial mass far detector module (17 kt total LAr mass), is a significant experiment in its own right. With a total liquid argon (LAr) mass of 0.77 kt, it represents the largest monolithic single phase LArTPC detector to be built to date. It is housed in an extension to the EHN1 hall in the North Area, where the CERN NP is providing a new dedicated charged-particle test beamline. ProtoDUNE-SP aims to take its first beam data before the LHC long shutdown (LS2) at the end of 2018. ProtoDUNE-SP prototypes the designs of most of the single-phase DUNE far detector module (DUNE-SP) components at a 1:1 scale, with an extrapolation of abo...

  7. Nonorthogonal multiple access and carrierless amplitude phase modulation for flexible multiuser provisioning in 5G mobile networks

    NARCIS (Netherlands)

    Altabas, J.A.; Rommel, S.; Puerta, R.; Izquierdo, D.; Ignacio Garces, J.; Antonio Lazaro, J.; Vegas Olmos, J.J.; Tafur Monroy, I.

    2017-01-01

    In this paper, a combined nonorthogonal multiple access (NOMA) and multiband carrierless amplitude phase modulation (multiCAP) scheme is proposed for capacity enhancement of and flexible resource provisioning in 5G mobile networks. The proposed scheme is experimentally evaluated over a W-band

  8. Low-Cost Planar MM-Wave Phased Array Antenna for Use in Mobile Satellite (MSAT) Platforms

    DEFF Research Database (Denmark)

    Ojaroudiparchin, Naser; Shen, Ming; Pedersen, Gert F.

    2015-01-01

    In this paper, a compact 8×8 phased array antenna for mobile satellite (MSAT) devices is designed and investigated. 64-elements of 22 GHz patch antennas with coaxial-probe feeds have been used for the proposed planar design. The antenna is designed on a low-cost FR4 substrate with thickness, diel...

  9. A Planar Switchable 3-D-Coverage Phased Array Antenna and Its User Effects for 28-GHz Mobile Terminal Applications

    DEFF Research Database (Denmark)

    Zhang, Shuai; Chen, Xiaoming; Syrytsin, Igor A.

    2017-01-01

    This paper introduces a planar switchable 3D-coverage phased array for 28 GHz mobile terminal applications. In order to realize 3D-coverage beam scan with a simple planar array, chassis surface waves are efficiently excited and controlled by three identical slot subarrays. Three subarrays switch...

  10. 77 FR 7152 - Mobility Fund Phase I Auction Scheduled for September 27, 2012; Comment Sought on Competitive...

    Science.gov (United States)

    2012-02-10

    ... considered 3G or better: EV-DO, EV-DO Rev A, UMTS/HSPA, HSPA+, WiMAX, and LTE. If the American Roamer data... eligible census block for purposes of comparing bids and measuring the performance of Mobility Fund Phase I...

  11. Mobile phase effects on the retention on polar columns with special attention to the dual hydrophilic interaction-reversed-phase liquid chromatography mechanism, a review.

    Science.gov (United States)

    Jandera, Pavel; Hájek, Tomáš

    2018-01-01

    Hydrophilic interaction liquid chromatography on polar columns in aqueous-organic mobile phases has become increasingly popular for the separation of many biologically important compounds in chemical, environmental, food, toxicological, and other samples. In spite of many new applications appearing in literature, the retention mechanism is still controversial. This review addresses recent progress in understanding of the retention models in hydrophilic interaction liquid chromatography. The main attention is focused on the role of water, both adsorbed by the column and contained in the bulk mobile phase. Further, the theoretical retention models in the isocratic and gradient elution modes are discussed. The dual hydrophilic interaction liquid chromatography reversed-phase retention mechanism on polar columns is treated in detail, especially with respect to the practical use in one- and two-dimensional liquid chromatography separations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Some new possibilities for the diagnostics of single-phase and two-phase plasma jets

    Energy Technology Data Exchange (ETDEWEB)

    Goldfarb, V M

    1979-02-01

    The literature on three classes of methods for the diagnostics of plasma jets is reviewed. These classes include nonintrusive measurements (spectroscopy, refractometry, scatterometry, and plasma velocimetry) intrusive measurements (electrostatic probes and calorimeters) and measurements of solid-phase properties (pyrometry, particle track records, diffractometry, light attenuation measurements, and laser Doppler velocimeters).

  13. Tunable phase transition in single-layer TiSe2 via electric field

    Science.gov (United States)

    Liu, Lei; Zhuang, Houlong L.

    2018-06-01

    Phase transition represents an intriguing physical phenomenon that exists in a number of single-layer transition-metal dichalcogenides. This phenomenon often occurs below a critical temperature and breaks the long-range crystalline order leading to a reconstructed superstructure called the charge-density wave (CDW) structure, which can therefore be recovered by external stimuli such as temperature. Alternatively, we show here that another external stimulation, electric field can also result in the phase transition between the regular and CDW structures of a single-layer transition-metal dichalcogenide. We used single-layer TiSe2 as an example to elucidate the mechanism of the CDW followed by calculations of the electronic structure using a hybrid density functional. We found that applying electric field can tune the phase transition between the 1T and CDW phases of single-layer TiSe2. Our work opens up a route of tuning the phase transition of single-layer materials via electric field.

  14. A Simple and Consistent Equation of State for Sodium in the Single Phase and Two Phase Regions

    International Nuclear Information System (INIS)

    Breton, J.P.

    1976-01-01

    An equation of state valid over an extended temperature and density range has been derived. Then, the following properties have been deduced: coefficient of thermal expansion, isothermal coefficient of bulk compressibility, thermal pressure coefficient, heat capacity at constant pressure, at constant volume, along the saturation curve for liquid, for vapor, heat of vaporization, speed of sound, and finally the Mollier diagram and the entropy diagram. All the obtained properties are thermodynamically consistent and satisfy the basic relations of thermodynamics for both single phase and two-phase regions. Experimental results were always used when available

  15. A simple and consistent equation of state for sodium in the single phase and two phase regions

    International Nuclear Information System (INIS)

    Breton, J.P.

    1976-01-01

    An equation of state valid over an extended temperature and density range has been derived. Then, the following properties have been deduced : coefficient of thermal expansion, isothermal coefficient of bulk compressibility, thermal pressure coefficient, heat capacity at constant pressure, at constant volume, along the saturation curve for liquid, for vapor, heat of vaporization, speed of sound, and finally the Mollier diagram and the entropy diagram. All the obtained properties are thermodynamically consistent and satisfy the basic relations of thermodynamics for both single phase and two-phase regions. Experimental results were always used when available. (auth.)

  16. Enhanced mobility of non aqueous phase liquid (NAPL) during drying of wet sand

    Science.gov (United States)

    Govindarajan, Dhivakar; Deshpande, Abhijit P.; Raghunathan, Ravikrishna

    2018-02-01

    Enhanced upward mobility of a non aqueous phase liquid (NAPL) present in wet sand during natural drying, and in the absence of any external pressure gradients, is reported for the first time. This mobility was significantly higher than that expected from capillary rise. Experiments were performed in a glass column with a small layer of NAPL-saturated sand trapped between two layers of water-saturated sand. Drying of the wet sand was induced by flow of air across the top surface of the wet sand. The upward movement of the NAPL, in the direction of water transport, commenced when the drying effect reached the location of the NAPL and continued as long as there was significant water evaporation in the vicinity of NAPL, indicating a clear correlation between the NAPL rise and water evaporation. The magnitude and the rate of NAPL rise was measured at different water evaporation rates, different initial locations of the NAPL, different grain size of the sand and the type of NAPL (on the basis of different NAPL-glass contact angle, viscosity and density). A positive correlation was observed between average rate of NAPL rise and the water evaporation while a negative correlation was obtained between the average NAPL rise rate and the NAPL properties of contact angle, viscosity and density. There was no significant correlation of average NAPL rise rate with variation of sand grain size between 0.1 to 0.5 mm. Based on these observations and on previous studies reported in the literature, two possible mechanisms are hypothesized -a) the effect of the spreading coefficient resulting in the wetting of NAPL on the water films created and b) a moving water film due to evaporation that "drags" the NAPL upwards. The NAPL rise reported in this paper has implications in fate and transport of chemicals in NAPL contaminated porous media such as soils and exposed dredged sediment material, which are subjected to varying water saturation levels due to drying and rewetting.

  17. Phase-and-amplitude recovery from a single phase-contrast image using partially spatially coherent x-ray radiation

    Science.gov (United States)

    Beltran, Mario A.; Paganin, David M.; Pelliccia, Daniele

    2018-05-01

    A simple method of phase-and-amplitude extraction is derived that corrects for image blurring induced by partially spatially coherent incident illumination using only a single intensity image as input. The method is based on Fresnel diffraction theory for the case of high Fresnel number, merged with the space-frequency description formalism used to quantify partially coherent fields and assumes the object under study is composed of a single-material. A priori knowledge of the object’s complex refractive index and information obtained by characterizing the spatial coherence of the source is required. The algorithm was applied to propagation-based phase-contrast data measured with a laboratory-based micro-focus x-ray source. The blurring due to the finite spatial extent of the source is embedded within the algorithm as a simple correction term to the so-called Paganin algorithm and is also numerically stable in the presence of noise.

  18. Theoretical prediction of high carrier mobility in single-walled black phosphorus nanotubes

    Science.gov (United States)

    Li, Q. F.; Wang, H. F.; Yang, C. H.; Li, Q. Q.; Rao, W. F.

    2018-05-01

    One-dimensional semiconductors are promising materials for high-performance nanoscale devices. Using the first-principles calculations combined with deformation potential approximation, we study the electronic structures and carrier transport properties of black phosphorus nanotubes (BPNTs). It is found that both armchair and zigzag BPNTs with diameter 13.5-18.5 Å are direct bandgap semiconductors. At a similar diameter, the carrier mobility of zigzag BPNT is one order of magnitude larger than that of armchair BPNT. For armchair BPNTs, the electron mobility is about 90.70-155.33 cm2 V-1 s-1 at room temperature, which is about three times of its hole counterpart. For zigzag BPNTs, the maximum mobility can reach 2.87 ×103 cm2 V-1 s-1. Furthermore, the electronic properties can be effectively tuned by the strain. For zigzag (0,13) nanotube, there is a direct-to-indirect band gap transition at a tensile strain of about 6%. Moreover, the electron mobility is boosted sharply by one order of magnitude by applying the compressive or tensile strain. The electron mobility increases to 14.05 ×103 cm2 V-1 s-1 at a tensile strain of 9%. Our calculations highlight the tunable electronic properties and superior carrier mobility of BPNTs that are promising for interesting applications in future nano-electronic devices.

  19. Mobile hot cell transition design phase study for radioactive waste treatment on the Hanford reservation site

    International Nuclear Information System (INIS)

    Pons, Y.

    2010-01-01

    shipped to BNF number 164, named CEDRA on Cadarache site (in operation in 2009). AREVA TA (ATA) is pleased to provide AREVA Federal Services (AFS) a phased plan to provide an Adaptation Design Technical Report and Organization. This approach will facilitate the assessment of the Final design Phase (After September 2010) and funding to support the engineering, procurement, and construction planning leading to the fabrication of a Mobile Hot Cell (MHC). (author)

  20. Predicting the optimal process window for the coating of single-crystalline organic films with mobilities exceeding 7 cm2/Vs.

    Science.gov (United States)

    Janneck, Robby; Vercesi, Federico; Heremans, Paul; Genoe, Jan; Rolin, Cedric

    2016-09-01

    Organic thin film transistors (OTFTs) based on single crystalline thin films of organic semiconductors have seen considerable development in the recent years. The most successful method for the fabrication of single crystalline films are solution-based meniscus guided coating techniques such as dip-coating, solution shearing or zone casting. These upscalable methods enable rapid and efficient film formation without additional processing steps. The single-crystalline film quality is strongly dependent on solvent choice, substrate temperature and coating speed. So far, however, process optimization has been conducted by trial and error methods, involving, for example, the variation of coating speeds over several orders of magnitude. Through a systematic study of solvent phase change dynamics in the meniscus region, we develop a theoretical framework that links the optimal coating speed to the solvent choice and the substrate temperature. In this way, we can accurately predict an optimal processing window, enabling fast process optimization. Our approach is verified through systematic OTFT fabrication based on films grown with different semiconductors, solvents and substrate temperatures. The use of best predicted coating speeds delivers state of the art devices. In the case of C8BTBT, OTFTs show well-behaved characteristics with mobilities up to 7 cm2/Vs and onset voltages close to 0 V. Our approach also explains well optimal recipes published in the literature. This route considerably accelerates parameter screening for all meniscus guided coating techniques and unveils the physics of single crystalline film formation.

  1. Reliability Evaluation of a Single-phase H-bridge Inverter with Integrated Active Power Decoupling

    DEFF Research Database (Denmark)

    Tang, Junchaojie; Wang, Haoran; Ma, Siyuan

    2016-01-01

    it with the traditional passive DC-link solution. The converter level reliability is obtained by component level electro-thermal stress modeling, lifetime model, Weibull distribution, and Reliability Block Diagram (RBD) method. The results are demonstrated by a 2 kW single-phase inverter application.......Various power decoupling methods have been proposed recently to replace the DC-link Electrolytic Capacitors (E-caps) in single-phase conversion system, in order to extend the lifetime and improve the reliability of the DC-link. However, it is still an open question whether the converter level...... reliability becomes better or not, since additional components are introduced and the loading of the existing components may be changed. This paper aims to study the converter level reliability of a single-phase full-bridge inverter with two kinds of active power decoupling module and to compare...

  2. High Quality Model Predictive Control for Single Phase Grid Connected Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Zangeneh Bighash, Esmaeil; Sadeghzadeh, Seyed Mohammad; Ebrahimzadeh, Esmaeil

    2018-01-01

    Single phase grid-connected inverters with LCL filter are widely used to connect the photovoltaic systems to the utility grid. Among the presented control schemes, predictive control methods are faster and more accurate but are more complex to implement. Recently, the model-predictive control...... algorithm for single-phase inverter has been presented, where the algorithm implementation is straightforward. In the proposed approach, all switching states are tested in each switching period to achieve the control objectives. However, since the number of the switching states in single-phase inverter...... is low, the inverter output current has a high total harmonic distortions. In order to reduce the total harmonic distortions of the injected current, this paper presents a high-quality model-predictive control for one of the newest structure of the grid connected photovoltaic inverter, i.e., HERIC...

  3. Solid phase epitaxial growth of high mobility La:BaSnO_3 thin films co-doped with interstitial hydrogen

    International Nuclear Information System (INIS)

    Niedermeier, Christian A.; Rhode, Sneha; Fearn, Sarah; Moram, Michelle A.; Ide, Keisuke; Hiramatsu, Hidenori; Hosono, Hideo; Kamiya, Toshio

    2016-01-01

    This work presents the solid phase epitaxial growth of high mobility La:BaSnO_3 thin films on SrTiO_3 single crystal substrates by crystallization through thermal annealing of nanocrystalline thin films prepared by pulsed laser deposition at room temperature. The La:BaSnO_3 thin films show high epitaxial quality and Hall mobilities up to 26 ± 1 cm"2/Vs. Secondary ion mass spectroscopy is used to determine the La concentration profile in the La:BaSnO_3 thin films, and a 9%–16% La doping activation efficiency is obtained. An investigation of H doping to BaSnO_3 thin films is presented employing H plasma treatment at room temperature. Carrier concentrations in previously insulating BaSnO_3 thin films were increased to 3 × 10"1"9" cm"−"3 and in La:BaSnO_3 thin films from 6 × 10"1"9" cm"−"3 to 1.5 × 10"2"0" cm"−"3, supporting a theoretical prediction that interstitial H serves as an excellent n-type dopant. An analysis of the free electron absorption by infrared spectroscopy yields a small (H,La):BaSnO_3 electron effective mass of 0.27 ± 0.05 m_0 and an optical mobility of 26 ± 7 cm"2/Vs. As compared to La:BaSnO_3 single crystals, the smaller electron mobility in epitaxial thin films grown on SrTiO_3 substrates is ascribed to threading dislocations as observed in high resolution transmission electron micrographs.

  4. Phase retrieval from a single fringe pattern by using empirical wavelet transform

    International Nuclear Information System (INIS)

    Guo, Xiaopeng; Zhao, Hong; Wang, Xin

    2015-01-01

    Phase retrieval from a single fringe pattern is one of the key tasks in optical metrology. In this paper, we present a new method for phase retrieval from a single fringe pattern based on empirical wavelet transform. In the proposed method, a fringe pattern can be effectively divided into three components: nonuniform background, fringes and random noise, which are described in different sub-pass. So the phase distribution information can be robustly extracted from fringes representing a fundamental frequency component. In simulation and a practical projection fringes test, the performance of the present method is successfully verified by comparing with the conventional wavelet transform method in terms of both image quality and phase estimation errors. (paper)

  5. Algorithms for image recovery calculation in extended single-shot phase-shifting digital holography

    Science.gov (United States)

    Hasegawa, Shin-ya; Hirata, Ryo

    2018-04-01

    The single-shot phase-shifting method of image recovery using an inclined reference wave has the advantages of reducing the effects of vibration, being capable of operating in real time, and affording low-cost sensing. In this method, relatively low reference angles compared with that in the conventional method using phase shift between three or four pixels has been required. We propose an extended single-shot phase-shifting technique which uses the multiple-step phase-shifting algorithm and the corresponding multiple pixels which are the same as that of the period of an interference fringe. We have verified the theory underlying this recovery method by means of Fourier spectral analysis and its effectiveness by evaluating the visibility of the image using a high-resolution pattern. Finally, we have demonstrated high-contrast image recovery experimentally using a resolution chart. This method can be used in a variety of applications such as color holographic interferometry.

  6. Single-phase dual-energy CT urography in the evaluation of haematuria.

    Science.gov (United States)

    Ascenti, G; Mileto, A; Gaeta, M; Blandino, A; Mazziotti, S; Scribano, E

    2013-02-01

    To assess the value of a single-phase dual-energy computed tomography (DECT) urography protocol with synchronous nephrographic-excretory phase enhancement and to calculate the potential dose reduction by omitting the unenhanced scan. Eighty-four patients referred for haematuria underwent CT urography using a protocol that included single-energy unenhanced and dual-energy contrast-enhanced with synchronous nephrographic-excretory phase scans. DECT-based images [virtual unenhanced (VUE), weighted average, and colour-coded iodine overlay] were reconstructed. Opacification degree by contrast media of the upper urinary tract, and image quality of virtual unenhanced images were independently evaluated using a four-point scale. The diagnostic accuracy in detecting urothelial tumours on DECT-based images was determined. The dose of a theoretical dual-phase single-energy protocol was obtained by multiplying the effective dose of the unenhanced single-energy acquisition by two. Radiation dose saving by omitting the unenhanced scan was calculated. The degree of opacification was scored as optimal or good in 86.9% of cases (k = 0.72); VUE image quality was excellent or good in 83.3% of cases (k = 0.82). Sensitivity, specificity, positive predictive value, and negative predictive value for urothelial tumours detection were 85.7, 98.6, 92.3, and 97.1%. Omission of the unenhanced scan led to a mean dose reduction of 42.7 ± 5%. Single-phase DECT urography with synchronous nephrographic-excretory phase enhancement represents an accurate "all-in-one'' approach with a radiation dose saving up to 45% compared with a standard dual-phase protocol. Copyright © 2012 The Royal College of Radiologists. All rights reserved.

  7. Single-phase dual-energy CT urography in the evaluation of haematuria

    International Nuclear Information System (INIS)

    Ascenti, G.; Mileto, A.; Gaeta, M.; Blandino, A.; Mazziotti, S.; Scribano, E.

    2013-01-01

    Aim: To assess the value of a single-phase dual-energy computed tomography (DECT) urography protocol with synchronous nephrographic–excretory phase enhancement and to calculate the potential dose reduction by omitting the unenhanced scan. Materials and methods: Eighty-four patients referred for haematuria underwent CT urography using a protocol that included single-energy unenhanced and dual-energy contrast-enhanced with synchronous nephrographic–excretory phase scans. DECT-based images [virtual unenhanced (VUE), weighted average, and colour-coded iodine overlay] were reconstructed. Opacification degree by contrast media of the upper urinary tract, and image quality of virtual unenhanced images were independently evaluated using a four-point scale. The diagnostic accuracy in detecting urothelial tumours on DECT-based images was determined. The dose of a theoretical dual-phase single-energy protocol was obtained by multiplying the effective dose of the unenhanced single-energy acquisition by two. Radiation dose saving by omitting the unenhanced scan was calculated. Results: The degree of opacification was scored as optimal or good in 86.9% of cases (k = 0.72); VUE image quality was excellent or good in 83.3% of cases (k = 0.82). Sensitivity, specificity, positive predictive value, and negative predictive value for urothelial tumours detection were 85.7, 98.6, 92.3, and 97.1%. Omission of the unenhanced scan led to a mean dose reduction of 42.7 ± 5%. Conclusion: Single-phase DECT urography with synchronous nephrographic–excretory phase enhancement represents an accurate “all-in-one’’ approach with a radiation dose saving up to 45% compared with a standard dual-phase protocol.

  8. Single-Phase Single-Stage Grid Tied Solar PV System with Active Power Filtering Using Power Balance Theory

    Science.gov (United States)

    Singh, Yashi; Hussain, Ikhlaq; Singh, Bhim; Mishra, Sukumar

    2018-03-01

    In this paper, power quality features such as harmonics mitigation, power factor correction with active power filtering are addressed in a single-stage, single-phase solar photovoltaic (PV) grid tied system. The Power Balance Theory (PBT) with perturb and observe based maximum power point tracking algorithm is proposed for the mitigation of power quality problems in a solar PV grid tied system. The solar PV array is interfaced to a single phase AC grid through a Voltage Source Converter (VSC), which provides active power flow from a solar PV array to the grid as well as to the load and it performs harmonics mitigation using PBT based control. The solar PV array power varies with sunlight and due to this, the solar PV grid tied VSC works only 8-10 h per day. At night, when PV power is zero, the VSC works as an active power filter for power quality improvement, and the load active power is delivered by the grid to the load connected at the point of common coupling. This increases the effective utilization of a VSC. The system is modelled and simulated using MATLAB and simulated responses of the system at nonlinear loads and varying environmental conditions are also validated experimentally on a prototype developed in the laboratory.

  9. Tandem differential mobility analysis-mass spectrometry reveals partial gas-phase collapse of the GroEL complex.

    Science.gov (United States)

    Hogan, Christopher J; Ruotolo, Brandon T; Robinson, Carol V; Fernandez de la Mora, Juan

    2011-04-07

    A parallel-plate differential mobility analyzer and a time-of-flight mass spectrometer (DMA-MS) are used in series to measure true mobility in dry atmospheric pressure air for mass-resolved electrosprayed GroEL tetradecamers (14-mers; ~800 kDa). Narrow mobility peaks are found (2.6-2.9% fwhm); hence, precise mobilities can be obtained for these ions without collisional activation, just following their generation by electrospray ionization. In contrast to previous studies, two conformers are found with mobilities (Z) differing by ~5% at charge state z ~ 79. By extrapolating to small z, a common mobility/charge ratio Z(0)/z = 0.0117 cm(2) V(-1) s(-1) is found for both conformers. When interpreted as if the GroEL ion surface were smooth and the gas molecule-protein collisions were perfectly elastic and specular, this mobility yields an experimental collision cross section, Ω, 11% smaller than in an earlier measurement, and close to the cross section, A(C,crystal), expected for the crystal structure (determined by a geometric approximation). However, the similarity between Ω and A(C,crystal) does not imply a coincidence between the native and gas-phase structures. The nonideal nature of protein-gas molecule collisions introduces a drag enhancement factor, ξ = 1.36, with which the true cross section A(C) is related to Ω via A(C) = Ω/ξ. Therefore, A(C) for GroEL 14-mer ions determined by DMA measurements is 0.69A(C,crystal). The factor 1.36 used here is based on the experimental Stokes-Millikan equation, as well as on prior and new numerical modeling accounting for multiple scattering events via exact hard-sphere scattering calculations. Therefore, we conclude that the gas-phase structure of the GroEL complex as electrosprayed is substantially more compact than the corresponding X-ray crystal structure.

  10. Indirect Matrix Converter for Hybrid Electric Vehicle Application with Three-Phase and Single-Phase Outputs

    Directory of Open Access Journals (Sweden)

    Yeongsu Bak

    2015-04-01

    Full Text Available This paper presents an indirect matrix converter (IMC topology for hybrid electric vehicle (HEV application with three-phase and single-phase outputs. The HEV includes mechanical, electrical, control, and electrochemical systems among others. In the mechanical system, a traction motor and a compressor motor are used to drive the HEV. The traction motor and the compressor motor are usually operated as three-phase and single-phase motors, respectively. In this respect, a dual AC-drive system can operate the traction and the compressor motor simultaneously. Furthermore, compared to a conventional dual matrix converter system, the proposed topology can reduce the number of switches that the dual outputs share with a DC-link. The application of this system for HEV has advantages, like long lifetime and reduced volume due to the lack of a DC-link. The proposed control strategy and modulation schemes ensure the sinusoidal input and output waveforms and bidirectional power transmission. The proposed system for the HEV application is verified by simulation and experiments.

  11. A review of single-phase grid-connected inverters for photovoltaic modules

    DEFF Research Database (Denmark)

    Kjaer, Soren Baekhoej; Pedersen, John Kim; Blaabjerg, Frede

    2005-01-01

    -phase grid; 3) whether they utilizes a transformer (either line or high frequency) or not; and 4) the type of grid-connected power stage. Various inverter topologies are presented, compared, and evaluated against demands, lifetime, component ratings, and cost. Finally, some of the topologies are pointed out......This review focuses on inverter technologies for connecting photovoltaic (PV) modules to a single-phase grid. The inverters are categorized into four classifications: 1) the number of power processing stages in cascade; 2) the type of power decoupling between the PV module(s) and the single...

  12. Synchronization in single-phase grid-connected photovoltaic systems under grid faults

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede

    2012-01-01

    The highly increasing penetration of single-phase photovoltaic (PV) systems pushes the grid requirements related to the integration of PV power systems to be updated. These upcoming regulations are expected to direct the grid-connected renewable generators to support the grid operation and stabil......The highly increasing penetration of single-phase photovoltaic (PV) systems pushes the grid requirements related to the integration of PV power systems to be updated. These upcoming regulations are expected to direct the grid-connected renewable generators to support the grid operation...

  13. Single phase cascaded H5 inverter with leakage current elimination for transformerless photovoltaic system

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Jia, X.; Lu, Z.

    2016-01-01

    Leakage current reduction is one of the important issues for the transformelress PV systems. In this paper, the transformerless single-phase cascaded H-bridge PV inverter is investigated. The common mode model for the cascaded H4 inverter is analyzed. And the reason why the conventional cascade H4...... inverter fails to reduce the leakage current is clarified. In order to solve the problem, a new cascaded H5 inverter is proposed to solve the leakage current issue. Finally, the experimental results are presented to verify the effectiveness of the proposed topology with the leakage current reduction...... for the single-phase transformerless PV systems....

  14. Challenges in thermal design of industrial single-phase power inverter

    Directory of Open Access Journals (Sweden)

    Ninković Predrag

    2016-01-01

    Full Text Available This paper presents the influence of thermal aspects in design process of an industrial single-phase inverter, choice of its topology and components. Stringent design inputs like very high overload level, demand for natural cooling and very wide input voltage range have made conventional circuit topology inappropriate therefore asking for alternative solution. Different power losses calculations in semiconductors are performed and compared, outlining the guidelines how to choose the final topology. Some recommendations in power magnetic components design are given. Based on the final project, a 20kVA single-phase inverter for thermal power plant supervisory and control system is designed and commissioned.

  15. Single-Phase Hybrid Switched Reluctance Motor for Low-Power Low-Cost Applications

    DEFF Research Database (Denmark)

    Lu, Kaiyuan; Rasmussen, Peter Omand; Jakobsen, Uffe

    2011-01-01

    This paper presents a new single-phase, Hybrid Switched Reluctance (HSR) motor for low-cost, low-power, pump or fan drive systems. Its single-phase configuration allows use of a simple converter to reduce the system cost. Cheap ferrite magnets are used and arranged in a special flux concentration...... manner to increase effectively the torque density and efficiency of this machine. The efficiency of this machine is comparable to the efficiency of a traditional permanent magnet machine in the similar power range. The cogging torque, due to the existence of the permanent magnetic field, is beneficially...

  16. An Open-Loop Grid Synchronization Approach for Single-Phase Applications

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2018-01-01

    in the presence of frequency drifts. This is particularly true in single-phase applications, where the lack of multiple independent input signals makes the implementation of the synchronization technique difficult. The aim of this paper is to develop an effective OLS technique for single-phase power and energy...... applications. The proposed OLS method benefits from a straightforward implementation, a fast dynamic response (a response time less than two cycles of the nominal frequency), and a complete immunity against the DC component in the grid voltage. In addition, the designed OLS method totally blocks (significantly...

  17. Fractional single-phase-lagging heat conduction model for describing anomalous diffusion

    Directory of Open Access Journals (Sweden)

    T.N. Mishra

    2016-03-01

    Full Text Available The fractional single-phase-lagging (FSPL heat conduction model is obtained by combining scalar time fractional conservation equation to the single-phase-lagging (SPL heat conduction model. Based on the FSPL heat conduction model, anomalous diffusion within a finite thin film is investigated. The effect of different parameters on solution has been observed and studied the asymptotic behavior of the FSPL model. The analytical solution is obtained using Laplace transform method. The whole analysis is presented in dimensionless form. Numerical examples of particular interest have been studied and discussed in details.

  18. Modeling and Stability Assessment of Single-Phase Grid Synchronization Techniques

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Vasquez, Juan

    2018-01-01

    (GSTs) is of vital importance. This task is most often based on obtaining a linear time-invariant (LTI) model for the GST and applying standard stability tests to it. Another option is modeling and dynamics/stability assessment of GSTs in the linear time-periodic (LTP) framework, which has received...... a very little attention. In this letter, the procedure of deriving the LTP model for single-phase GSTs is first demonstrated. The accuracy of the LTP model in predicting the GST dynamic behavior and stability is then evaluated and compared with that of the LTI one. Two well-known single-phase GSTs, i...

  19. Zero-Voltage Ride-Through Capability of Single-Phase Grid-Connected Photovoltaic Systems

    Directory of Open Access Journals (Sweden)

    Zhen Zhang

    2017-03-01

    Full Text Available Distributed renewable energy systems play an increasing role in today’s energy paradigm. Thus, intensive research activities have been centered on improving the performance of renewable energy systems, including photovoltaic (PV systems, which should be of multiple-functionality. That is, the PV systems should be more intelligent in the consideration of grid stability, reliability, and fault protection. Therefore, in this paper, the performance of single-phase grid-connected PV systems under an extreme grid fault (i.e., when the grid voltage dips to zero is explored. It has been revealed that combining a fast and accurate synchronization mechanism with appropriate control strategies for the zero-voltage ride-through (ZVRT operation is mandatory. Accordingly, the representative synchronization techniques (i.e., the phase-locked loop (PLL methods in the ZVRT operation are compared in terms of detection precision and dynamic response. It shows that the second-order generalized integrator (SOGI-PLL is a promising solution for single-phase systems in the case of fault ride-through. A control strategy by modifying the SOGI-PLL scheme is then introduced to single-phase grid-connected PV systems for ZVRT operation. Simulations are performed to verify the discussions. The results have demonstrated that the proposed method can help single-phase PV systems to temporarily ride through zero-voltage faults with good dynamics.

  20. Ionic Mobility and Phase Transitions in Perovskite Oxides for Energy Application

    Directory of Open Access Journals (Sweden)

    Francesco Cordero

    2017-02-01

    Full Text Available Perovskite oxides find applications or are studied in many fields related to energy production, accumulation and saving. The most obvious application is oxygen or proton conductors in fuel cells (SOFCs, but the (antiferroelectric compositions may find application in high energy capacitors for energy storage, efficient electrocaloric cooling, and electromechanical energy harvesting. In SOFCs, the diffusion of O vacancies and other mobile ionic species, such as H+, are at the base of the functioning of the device, while in the other cases they constitute unwanted defects that reduce the performance and life-time of the device. Similarly, the (antiferroelectric phase transitions are a requisite for the use of some types of devices, but the accompanying domain walls can generate extended defects detrimental to the life of the material, and structural phase transformations should be avoided in SOFCs. All these phenomena can be studied by mechanical spectroscopy, the measurement of the complex elastic compliance as a function of temperature and frequency, which is the mechanical analogue of the dielectric susceptibility, but probes the elastic response and elastic dipoles instead of the dielectric response and electric dipoles. The two techniques can be combined to provide a comprehensive picture of the material properties. Examples are shown of the study of structural transitions and hopping and tunnelling processes of O vacancies and H in the ion conductor BaCe1-xYxO3-x and in SrTiO3-x, and of the aging and fatigue effects found in PZT at compositions where the ferro- and antiferroelectric states coexist.

  1. Quantum phase transitions in spin-1 X X Z chains with rhombic single-ion anisotropy

    Science.gov (United States)

    Ren, Jie; Wang, Yimin; You, Wen-Long

    2018-04-01

    We explore numerically the inverse participation ratios in the ground state of one-dimensional spin-1 X X Z chains with the rhombic single-ion anisotropy. By employing the techniques of density-matrix renormalization group, effects of the rhombic single-ion anisotropy on various information theoretical measures are investigated, such as the fidelity susceptibility, the quantum coherence, and the entanglement entropy. Their relations with the quantum phase transitions are also analyzed. The phase transitions from the Y -Néel phase to the large-Ex or the Haldane phase can be well characterized by the fidelity susceptibility. The second-order derivative of the ground-state energy indicates all the transitions are of second order. We also find that the quantum coherence, the entanglement entropy, the Schmidt gap, and the inverse participation ratios can be used to detect the critical points of quantum phase transitions. Results drawn from these quantum information observables agree well with each other. Finally we provide a ground-state phase diagram as functions of the exchange anisotropy Δ and the rhombic single-ion anisotropy E .

  2. Hydrodynamics of single- and two-phase flow in inclined rod arrays

    International Nuclear Information System (INIS)

    Ebeling-Koning, D.B.; Todreas, N.E.

    1983-09-01

    Required inputs for thermal-hydraulic codes are constitutive relations for fluid-solid flow resistance, in single-phase flow, and interfacial momentum exchange (relative phase motion), in two-phase flow. An inclined rod array air-water experiment was constructed to study the hydrodynamics of multidimensional porous medium flow in rod arrays. Velocities, pressures, and bubble distributions were measured in square rod arrays of P/d = 1.5, at 0, 30, 45, and 90 degree inclinations to the vertical flow direction. Constitutive models for single-phase flow resistance are reviewed, new comprehensive models developed, and an assessment with previously published and new data made. The principle of superimposing one-dimensional correlations proves successful for turbulent single-phase inclined flow. For bubbly two-phase incline flow a new flow separation phenomena was observed and modeled. A two-region liquid velocity model is developed to explain the experimentally observed phenomena. Fundamental data for bubbles rising in rod arrays were also taken

  3. Effect of completion geometry and phasing on single-phase liquid flow behaviour in horizontal wells

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, H.; Sarica, C.; Brill, P. [Tulsa Unov., OK (United States)

    1998-12-31

    The effects of completion geometries and the phasing and density of injection openings in horizontal wells was studied. A total of 1,257 tests were conducted for no fluid injections, no main flow at the test section inlet, and with fluid injection for Reynolds numbers ranging from 4,000 to 60,000 and for influx to main flow rate ratios ranging from 1/5 to 1/2000. Results demonstrated the dramatic effects of completion geometry, phasing density, Reynolds number and main flow rate on the pressure behaviour and therefore on the production behaviour of the well. A general friction factor expression for horizontal wells with multiple injection openings was developed based on the conservation of mass and momentum and using a commercial Computational Fluid Dynamics (CFD) computer program to determine the length of the flow developing region in a horizontal well. A field example is presented to show the importance of using the proper friction factor correlation to calculate the pressure drop in a horizontal well. 32 refs., 4 tabs., 20 figs.

  4. Liquid-solid phase transition of physical hydrogels subject to an externally applied electro-chemo-mechanical coupled field with mobile ionic species.

    Science.gov (United States)

    Wu, Tao; Li, Hua

    2017-08-09

    In this study, a model was multiphysically developed for the simulation of the phase transition of physical hydrogels between liquid solution and solid gel states, subject to an electro-chemo-mechanically coupled field, with the effect of the mobile ionic species in the solution. The present model consists of the governing equations for the equilibrium of forces and the conservation of mass, Maxwell's equations, and an evolution equation for the interface. Based on the second law of thermodynamics, the constitutive equations are formulated from the energy viewpoint, including a novel formulation of free energy with the effect of crosslink density. The present model may be reduced to Suo's non-equilibrium thermodynamic theory if the interface is ignored when only a single phase exists. It may also be reduced to Dolbow's model for gel-gel phase transition when the electric field is ignored. Therefore, the present model becomes more generalized since it is able to represent both the bulk phase and the interface behaviors, and the mechanical field is simultaneously coupled with both the electric and chemical fields. In the first case study, the system at equilibrium state was numerically investigated for analysis of the influences of the electrical and chemical potentials as well as the mechanical pressure externally imposed on the boundary of the system domain. The second case study presents a spherically symmetrical solution-gel phase transition at non-equilibrium states, with the emphasis on the evolution of both the interface and electrochemical potentials.

  5. Shot-noise-limited monitoring and phase locking of the motion of a single trapped ion.

    Science.gov (United States)

    Bushev, P; Hétet, G; Slodička, L; Rotter, D; Wilson, M A; Schmidt-Kaler, F; Eschner, J; Blatt, R

    2013-03-29

    We perform a high-resolution real-time readout of the motion of a single trapped and laser-cooled Ba+ ion. By using an interferometric setup, we demonstrate a shot-noise-limited measurement of thermal oscillations with a resolution of 4 times the standard quantum limit. We apply the real-time monitoring for phase control of the ion motion through a feedback loop, suppressing the photon recoil-induced phase diffusion. Because of the spectral narrowing in the phase-locked mode, the coherent ion oscillation is measured with a resolution of about 0.3 times the standard quantum limit.

  6. Theory of phase transformation and reorientation in single crystalline shape memory alloys

    International Nuclear Information System (INIS)

    Zhu, J J; Liang, N G; Cai, M; Liew, K M; Huang, W M

    2008-01-01

    A constitutive model, based on an (n+1)-phase mixture of the Mori–Tanaka average theory, has been developed for stress-induced martensitic transformation and reorientation in single crystalline shape memory alloys. Volume fractions of different martensite lattice correspondence variants are chosen as internal variables to describe microstructural evolution. Macroscopic Gibbs free energy for the phase transformation is derived with thermodynamics principles and the ensemble average method of micro-mechanics. The critical condition and the evolution equation are proposed for both the phase transition and reorientation. This model can also simulate interior hysteresis loops during loading/unloading by switching the critical driving forces when an opposite transition takes place

  7. Universal holonomic single quantum gates over a geometric spin with phase-modulated polarized light.

    Science.gov (United States)

    Ishida, Naoki; Nakamura, Takaaki; Tanaka, Touta; Mishima, Shota; Kano, Hiroki; Kuroiwa, Ryota; Sekiguchi, Yuhei; Kosaka, Hideo

    2018-05-15

    We demonstrate universal non-adiabatic non-abelian holonomic single quantum gates over a geometric electron spin with phase-modulated polarized light and 93% average fidelity. This allows purely geometric rotation around an arbitrary axis by any angle defined by light polarization and phase using a degenerate three-level Λ-type system in a negatively charged nitrogen-vacancy center in diamond. Since the control light is completely resonant to the ancillary excited state, the demonstrated holonomic gate not only is fast with low power, but also is precise without the dynamical phase being subject to control error and environmental noise. It thus allows pulse shaping for further fidelity.

  8. Berry phase of primordial scalar and tensor perturbations in single-field inflationary models

    Science.gov (United States)

    Balajany, Hamideh; Mehrafarin, Mohammad

    2018-06-01

    In the framework of the single-field slow-roll inflation, we derive the Hamiltonian of the linear primordial scalar and tensor perturbations in the form of time-dependent harmonic oscillator Hamiltonians. We find the invariant operators of the resulting Hamiltonians and use their eigenstates to calculate the adiabatic Berry phase for sub-horizon modes in terms of the Lewis-Riesenfeld phase. We conclude by discussing the discrepancy in the results of Pal et al. (2013) [21] for these Berry phases, which is resolved to yield agreement with our results.

  9. Improved state observers for sensorless single phase BLDC-PM motor drives

    DEFF Research Database (Denmark)

    Lepure, Liviu L.; Boldea, Ion; Andreescu, Gheorghe Daniel

    2010-01-01

    Two methods of extracting the rotor position and speed for a sensorless single phase BLDC-PM motor drive by measuring only the phase current are presented here. Both methods are based on a generated orthogonal flux system. The first method extracts the position information by using the tan−1...... function and then an improved observer is created by adding a 4th order harmonic term in the estimated position, while the second method uses a phase locked loop structure. The proposed state observers are detailed using simulation results and then validated by experimental results....

  10. Dual-Stack Single-Radio Communication Architecture for UAV Acting As a Mobile Node to Collect Data in WSNs

    Directory of Open Access Journals (Sweden)

    Ali Sayyed

    2015-09-01

    Full Text Available The use of mobile nodes to collect data in a Wireless Sensor Network (WSN has gained special attention over the last years. Some researchers explore the use of Unmanned Aerial Vehicles (UAVs as mobile node for such data-collection purposes. Analyzing these works, it is apparent that mobile nodes used in such scenarios are typically equipped with at least two different radio interfaces. The present work presents a Dual-Stack Single-Radio Communication Architecture (DSSRCA, which allows a UAV to communicate in a bidirectional manner with a WSN and a Sink node. The proposed architecture was specifically designed to support different network QoS requirements, such as best-effort and more reliable communications, attending both UAV-to-WSN and UAV-to-Sink communications needs. DSSRCA was implemented and tested on a real UAV, as detailed in this paper. This paper also includes a simulation analysis that addresses bandwidth consumption in an environmental monitoring application scenario. It includes an analysis of the data gathering rate that can be achieved considering different UAV flight speeds. Obtained results show the viability of using a single radio transmitter for collecting data from the WSN and forwarding such data to the Sink node.

  11. Dual-Stack Single-Radio Communication Architecture for UAV Acting As a Mobile Node to Collect Data in WSNs.

    Science.gov (United States)

    Sayyed, Ali; de Araújo, Gustavo Medeiros; Bodanese, João Paulo; Becker, Leandro Buss

    2015-09-16

    The use of mobile nodes to collect data in a Wireless Sensor Network (WSN) has gained special attention over the last years. Some researchers explore the use of Unmanned Aerial Vehicles (UAVs) as mobile node for such data-collection purposes. Analyzing these works, it is apparent that mobile nodes used in such scenarios are typically equipped with at least two different radio interfaces. The present work presents a Dual-Stack Single-Radio Communication Architecture (DSSRCA), which allows a UAV to communicate in a bidirectional manner with a WSN and a Sink node. The proposed architecture was specifically designed to support different network QoS requirements, such as best-effort and more reliable communications, attending both UAV-to-WSN and UAV-to-Sink communications needs. DSSRCA was implemented and tested on a real UAV, as detailed in this paper. This paper also includes a simulation analysis that addresses bandwidth consumption in an environmental monitoring application scenario. It includes an analysis of the data gathering rate that can be achieved considering different UAV flight speeds. Obtained results show the viability of using a single radio transmitter for collecting data from the WSN and forwarding such data to the Sink node.

  12. Modelling the transition between fixed and mobile bed conditions in two-phase free-surface flows: The Composite Riemann Problem and its numerical solution

    Science.gov (United States)

    Rosatti, Giorgio; Zugliani, Daniel

    2015-03-01

    In a two-phase free-surface flow, the transition from a mobile-bed condition to a fixed-bed one (and vice versa) occurs at a sharp interface across which the relevant system of partial differential equations changes abruptly. This leads to the possibility of conceiving a new type of Riemann Problem (RP), which we have called Composite Riemann Problem (CRP), where not only the initial constant values of the variables but also the system of equations change from left to right of a discontinuity. In this paper, we present a strategy for solving a CRP by reducing it to a standard RP of a single, composite system of equations. This can be obtained by combining the two original systems by means of a suitable weighting function, namely the erodibility variable, and the introduction of an appropriate differential equation for this quantity. In this way, the CRP problem can be analyzed theoretically with standard methods, and the features of the solutions can be clearly identified. In particular, a stationary contact wave is able to correctly describe the sharp transition between mobile- and fixed-bed conditions. A finite volume scheme based on the Multiple Averages Generalized Roe approach (Rosatti and Begnudelli (2013) [22]) was used to numerically solve the fixed-mobile CRP. Several test cases demonstrate the effectiveness, exact well balanceness and high accuracy of the scheme when applied to problems that fall within the physical range of applicability of the relevant mathematical model.

  13. Liquid Phase Deposition of Single-Phase Alpha-Copper-Indium-Diselenide

    Science.gov (United States)

    Hepp, Aloysius F.; Bailey, S.; Cowen, Jonathan; Lucas, L.; Ernst, Frank; Pirouz, P.

    2004-01-01

    The success of exploratory missions in outer space often depends on a highly efficient renewable energy supply, as provided by solar cells. Since future missions will demand large aggregates of solar cells, and space flight is expensive, the solar cells must furthermore be available at low costs and have a long lifetime and high resistance against structural damage introduced by irradiation with high energy electrons and protons. The photovoltaic materials that are presently available only partly fulfill all these requirements. Therefore, we propose to explore a new method for fabricating thin-films for cost-efficient solar cells with very high specific power,high irradiation resistance and long lifetime based on the alpha-phase of the Cu-In-Se system "alpha-CIS."

  14. [CLINICAL APPLICATION OF OXFORD MOBILE-BEARING BIPOLAR PROSTHESIS UNICOMPARTMENTAL KNEE ARTHROPLASTY FOR SINGLE COMPARTMENTAL KNEE OSTEOARTHRITIS].

    Science.gov (United States)

    Wang, Shangzeng; Cheng, Shao; Wang, Yisheng

    2016-01-01

    To evaluate the effectiveness of Oxford mobile-bearing bipolar prosthesis unicompartmental knee arthroplasty (UKA) in the treatment of single compartmental knee osteoarthritis. Between June 2011 and July 2013, 22 cases of single compartmental knee osteoarthritis were treated by Oxford mobile-bearing bipolar prosthesis UKA. Of 22 cases, 8 were male and 14 were female with an average age of 65 years (range, 45-80 years); the left knee was involved in 12 cases, and the right knee in 10 cases, with a mean disease duration of 32.5 months (range, 8-90 months). The mean weight was 55.2 kg (range, 50-65 kg), and the mean body mass index was 20.8 kg/m2 (range, 17-25 kg/m2). Osteoarthritis involved in the single knee medial compartment in all patients. Knee society score (KSS) and range of motion (ROM) were measured to evaluate the knee joint function. Primary healing of incision was obtained in all patients, and there was no complication of infection, bedsore, or deep venous thrombosis. Postoperative follow-up was 2-4 years (mean, 3.2 years). The X-ray films showed good position of prosthesis, no prosthesis dislocation, or periprosthetic infection during follow-up. Knee ROM, KSS function score, and KSS clinical score were significantly improved at 1 week after operation and at last follow-up when compared with preoperative ones (P 0.05). Oxford mobile-bearing bipolar prosthesis UKA is an effective method to treat single compartmental knee osteoarthritis, with the advantages of less trauma, earlier rehabilitation exercise, near physiological state in joint function, and less risk of complications.

  15. Position Control of the Single Spherical Wheel Mobile Robot by Using the Fuzzy Sliding Mode Controller

    OpenAIRE

    Hamed Navabi; Soroush Sadeghnejad; Sepehr Ramezani; Jacky Baltes

    2017-01-01

    A spherical wheel robot or Ballbot—a robot that balances on an actuated spherical ball—is a new and recent type of robot in the popular area of mobile robotics. This paper focuses on the modeling and control of such a robot. We apply the Lagrangian method to derive the governing dynamic equations of the system. We also describe a novel Fuzzy Sliding Mode Controller (FSMC) implemented to control a spherical wheel mobile robot. The nonlinear nature of the equations makes the controller nontrivi...

  16. Single and two-phase flow pressure drop for CANFLEX bundle

    Energy Technology Data Exchange (ETDEWEB)

    Park, Joo Hwan; Jun, Ji Su; Suk, Ho Chun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Dimmick, G R; Bullock, D E [Atomic Energy of Canada Limited, Ontario (Canada)

    1999-12-31

    Friction factor and two-phase flow frictional multiplier for a CANFLEX bundle are newly developed and presented in this paper. CANFLEX as a 43-element fuel bundle has been developed jointly by AECL/KAERI to provide greater operational flexibility for CANDU reactor operators and designers. Friction factor and two-phase flow frictional multiplier have been developed by using the experimental data of pressure drops obtained from two series of Freon-134a (R-134a) CHF tests with a string of simulated CANFLEX bundles in a single phase and a two-phase flow conditions. The friction factor for a CANFLEX bundle is found to be about 20% higher than that of Blasius for a smooth circular pipe. The pressure drop predicted by using the new correlations of friction factor and two-phase frictional multiplier are well agreed with the experimental pressure drop data of CANFLEX bundle within {+-} 5% error. 11 refs., 5 figs. (Author)

  17. Single and two-phase flow pressure drop for CANFLEX bundle

    Energy Technology Data Exchange (ETDEWEB)

    Park, Joo Hwan; Jun, Ji Su; Suk, Ho Chun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Dimmick, G. R.; Bullock, D. E. [Atomic Energy of Canada Limited, Ontario (Canada)

    1998-12-31

    Friction factor and two-phase flow frictional multiplier for a CANFLEX bundle are newly developed and presented in this paper. CANFLEX as a 43-element fuel bundle has been developed jointly by AECL/KAERI to provide greater operational flexibility for CANDU reactor operators and designers. Friction factor and two-phase flow frictional multiplier have been developed by using the experimental data of pressure drops obtained from two series of Freon-134a (R-134a) CHF tests with a string of simulated CANFLEX bundles in a single phase and a two-phase flow conditions. The friction factor for a CANFLEX bundle is found to be about 20% higher than that of Blasius for a smooth circular pipe. The pressure drop predicted by using the new correlations of friction factor and two-phase frictional multiplier are well agreed with the experimental pressure drop data of CANFLEX bundle within {+-} 5% error. 11 refs., 5 figs. (Author)

  18. Single phase computed tomography is equivalent to dual phase method for localizing hyperfunctioning parathyroid glands in patients with primary hyperparathyroidism: a retrospective review

    Directory of Open Access Journals (Sweden)

    Fanny Morón

    2017-08-01

    Full Text Available Objective This study aims to compare the sensitivity of dual phase (non-contrast and arterial versus single phase (arterial CT for detection of hyper-functioning parathyroid glands in patients with primary hyperparathyroidism. Methods The CT scans of thirty-two patients who have biochemical evidence of primary hyperparathyroidism, pathologically proven parathyroid adenomas, and pre-operative multiphase parathyroid imaging were evaluated retrospectively in order to compare the adequacy of single phase vs. dual phase CT scans for the detection of parathyroid adenomas. Results The parathyroid adenomas were localized in 83% of cases on single arterial phase CT and 80% of cases on dual phase CT. The specificity for localization of parathyroid tumor was 96% for single phase CT and 97% for dual phase CT. The results were not significantly different (p = 0.695. These results are similar to those found in the literature for multiphase CT of 55–94%. Conclusions Our study supports the use of a single arterial phase CT for the detection of hyperfunctioning parathyroid adenomas. Advances in knowledge: a single arterial phase CT has similar sensitivity for localizing parathyroid adenomas as dual phase CT and significantly reduces radiation dose to the patient.

  19. ARACMO: Advanced Regolith Anchoring for Cable-assisted Mobility, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — To enable future robotic exploration systems to have greater mobility capabilities on difficult terrain such as craters, cliffs, gullies, and skylights, Tethers...

  20. A 3-D Miniature LIDAR System for Mobile Robot Navigation, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Future lunar initiatives will demand sophisticated operation of mobile robotics platforms. In particular, lunar site operations will benefit from robots, both...

  1. A 3-D Miniature LIDAR System for Mobile Robot Navigation, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Future lunar site operations will benefit from mobile robots, both autonomous and tele-operated, that complement or replace human extravehicular activity....

  2. An efficiency improved single-phase PFC converter for electric vehicle charger applications

    DEFF Research Database (Denmark)

    Zhu, Dexuan; Tang, Yi; Jin, Chi

    2013-01-01

    This paper presents an efficiency improved single-phase power factor correction (PFC) converter with its target application to plug-in hybrid electric vehicle (PHEV) charging systems. The proposed PFC converter features sinusoidal input current, three-level output characteristic, and wide range...

  3. A double parameters measurement of steam-water two-phase flow with single orifice

    International Nuclear Information System (INIS)

    Zhong Shuoping; Tong Yunxian; Yu Meiying

    1992-08-01

    A double parameters measurement of steam-water two-phase flow with single orifice is described. An on-line measurement device based on micro-computer has been developed. The measured r.m.s error of steam quality is less than 6.5% and the measured relative r.m.s. error of mass flow rate is less than 9%

  4. Design and Implementation of Wireless Energy Meter System for Monitoring the Single Phase Supply

    OpenAIRE

    U. V, Prashanth B.

    2013-01-01

    Wireless energy meter is a system developed to serve as a basic single-phase energy meter with advanced functionalities such as Peak hour setting, Peak load setting Wireless reading transmission; further the system eliminates the role of a Meter Reader.

  5. Novel Motion Sensorless Control of Single Phase Brushless D.C. PM Motor Drive, with experiments

    DEFF Research Database (Denmark)

    Lepure, Liviu Ioan; Boldea, Ion; Andreescu, Gheorghe Daniel

    2010-01-01

    A motion sensorless control for single phase permanent magnet brushless d.c. (PM-BLDC) motor drives, based on flux integration and prior knowledge of the PM flux/position characteristic is proposed here and an adequate correction algorithm is adopted, in order to increase the robustness to noise...

  6. Single-Phase 3L PR Controlled qZS Inverter Connected to the Distorted Grid

    DEFF Research Database (Denmark)

    Makovenko, Elena; Husev, Oleksandr; Roncero-Clemente, Carlos

    2016-01-01

    This paper presents a single-phase three-level NPC qZS inverter connected to a distorted grid using PID and PR regulators. A case study system along with the control strategy are described. Tuning approaches for PID and PR regulators are addressed and validated by means of simulation results...

  7. PI and repetitive control for single phase inverter based on virtual rotating coordinate system

    Science.gov (United States)

    Li, Mengqi; Tong, Yibin; Jiang, Jiuchun; Liang, Jiangang

    2018-03-01

    Microgrid technology developed rapidly and nonlinear loads were connected increasingly. A new control strategy was proposed for single phase inverter when connected nonlinear loads under island condition. PI and repetitive compound controller was realized under synchronous rotating coordinate system and acquired high quality sinusoidal voltage output without voltage spike when loads step changed. Validity and correctness were verified by simulation using MATLAB/Simulink.

  8. Forest resources of southeast Alaska, 2000: results of a single-phase systematic sample.

    Science.gov (United States)

    Willem W.S. van Hees

    2003-01-01

    A baseline assessment of forest resources in southeast Alaska was made by using a single-phase, unstratified, systematic-grid sample, with ground plots established at each grid intersection. Ratio-of-means estimators were used to develop population estimates. Forests cover an estimated 48 percent of the 22.9-million-acre southeast Alaska inventory unit. Dominant forest...

  9. Modeling and Control of a Single-Phase Marine Cooling System

    DEFF Research Database (Denmark)

    Hansen, Michael; Stoustrup, Jakob; Bendtsen, Jan Dimon

    2013-01-01

    This paper presents two model-based control design approaches for a single-phase marine cooling system. Models are derived from first principles and aim at describing significant system dynamics including nonlinearities and transport delays, while keeping the model complexity low. The two...

  10. Benchmarking of grid fault modes in single-phase grid-connected photovoltaic systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang

    2012-01-01

    Pushed by the booming installations of single-phase photovoltaic (PV) systems, the grid demands regarding the integration of PV systems are expected to be modified. Hence, the future PV systems should become more active with functionalities of low voltage ride-through (LVRT) and the grid support...

  11. Frequency Adaptive Repetitive Control of Grid-Tied Single-Phase PV Inverters

    DEFF Research Database (Denmark)

    Zhou, Keliang; Yang, Yongheng; Blaabjerg, Frede

    2015-01-01

    . This paper thus explores a frequency adaptive repetitive control strategy for grid converters, which employs fractional delay filters in order to adapt to the change of the grid frequency. Case studies with experimental results of a single-phase grid-connected PV inverter system are provided to verify...

  12. The Effect of Grain Size on Mechanical Instability in Single-Phase Li-Alloy Anodes

    National Research Council Canada - National Science Library

    Wolfenstine, Jeff

    2000-01-01

    .... The results of this study suggest that decreasing the particle and/or grain size is not a practical approach to solving the mechanical instability problem of single phase Li alloys that are intended to be used as anodes in Li-ion batteries.

  13. Decoupling of fluctuating power in single-phase systems through a symmetrical half-bridge circuit

    DEFF Research Database (Denmark)

    Tang, Yi; Blaabjerg, Frede; Loh, Poh Chiang

    2014-01-01

    Single-phase AC/DC or DC/AC systems inherently subject to harmonic disturbance which is caused by the well-known double line frequency ripple power. This issue can be eased through the installation of bulky electrolytic capacitors in the dc-link, but such passive filtering approach may inevitably...

  14. Hybrid Control Method for a Single Phase PFC using a Low Cost Microcontroller

    DEFF Research Database (Denmark)

    Jakobsen, Lars Tønnes; Nielsen, Nils; Wolf, Christian

    2005-01-01

    This paper presents a hybrid control method for single phase boost PFCs. The high bandwidth current loop is analog while the voltage loop is implemented in an 8-bit microcontroller. The design focuses on minimizing the number of calculations done in the microcontroller. A 1kW prototype has been...

  15. A Generic Topology Derivation Method for Single-phase Converters with Active Capacitive DC-links

    DEFF Research Database (Denmark)

    Wang, Haoran; Wang, Huai; Zhu, Guorong

    2016-01-01

    capacitive DCDC- link solutions, but important aspects of the topology assess-ment, such as the total energy storage, overall capacitive energy buffer ratio, cost, and reliability are still not available. This paper proposes a generic topology derivation method of single-phase power converters...

  16. Flux Concentration and Pole Shaping in a Single Phase Hybrid Switched Reluctance Motor Drive

    DEFF Research Database (Denmark)

    Jakobsen, Uffe; Lu, Kaiyuan

    2010-01-01

    The single phase hybrid switched reluctance motor (HSRM) may be a good candidate for low-cost drives used for pump applications. This paper presents a new design of the HSRM with improved starting torque achieved by stator pole shaping, and a better arrangement of the embedded stator permanent...

  17. Modelling and simulation of multiple single - phase induction motor in parallel connection

    Directory of Open Access Journals (Sweden)

    Sujitjorn, S.

    2006-11-01

    Full Text Available A mathematical model for parallel connected n-multiple single-phase induction motors in generalized state-space form is proposed in this paper. The motor group draws electric power from one inverter. The model is developed by the dq-frame theory and was tested against four loading scenarios in which satisfactory results were obtained.

  18. Structural, vibrational and thermal characterization of phase transformation in L-histidinium bromide monohydrate single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Moura, G.M. [Universidade Federal do Maranhão, CCSST, Imperatriz, MA, 65900-410 (Brazil); Universidade Federal do Sul e Sudeste do Pará, ICEN, Marabá, PA 68505-080 (Brazil); Carvalho, J.O. [Universidade Federal do Maranhão, CCSST, Imperatriz, MA, 65900-410 (Brazil); Instituto Federal do Tocantins, Araguaína, TO, 77.826-170 (Brazil); Silva, M.C.D.; Façanha Filho, P.F. [Universidade Federal do Maranhão, CCSST, Imperatriz, MA, 65900-410 (Brazil); Santos, A.O. dos, E-mail: adenilson1@gmail.com [Universidade Federal do Maranhão, CCSST, Imperatriz, MA, 65900-410 (Brazil)

    2015-09-01

    L-Histidinium bromide monohydrate (LHBr) single crystal is a nonlinear optical material. In this work the high temperature phase transformation and the thermal stability of single crystals of LHBr was investigated by X-ray diffraction, thermogravimetric analysis, differential thermal analysis, differential scanning calorimetry and Raman spectroscopy. The results showed the LHBr phase transformation of orthorhombic (P2{sub 1}2{sub 1}2{sub 1}) to monoclinic system (P 1 2 1) at 120 °C, with the lattice parameters a = 12.162(1) Å, b = 16.821(2) Å, c = 19.477(2) Å and β = 108.56(2)°. These techniques are complementary and confirm the structural phase transformation due to loss water of crystallization. - Highlights: • -histidinium bromide single crystal was grown by slow evaporation technique. • X-ray diffraction characterize the high-temperature phase transformation. • The structural phase transformation occur due to loss of water of crystallization. • The LHBr thermal expansion coefficients exhibit an anisotropic behavior.

  19. Study of the mobilization of pollutants in soils of the Bogota Savanna - phase 1, Heavy Metals

    International Nuclear Information System (INIS)

    Gonzalez, Luz Myrian; Vargas Zarate, Orlando

    1997-01-01

    In this study the soils contamination of the Bogota Savanna was evaluated by heavy metals, that they have importance to be this the area of population's of the country bigger density, where the use of the soils has suffered changes in the last years that have affected its properties, as consequence of the not controlled growth of the urban area, of the industrialization and of the agricultural use not planned. As a first stage toward the risk evaluation for the presence of metals weighed in the soils of the Bogota Savanna, the concentrations of cadmium, cobalt, chromium, copper, manganese, nickel, lead, zinc, molybdenum, arsenic and mercury were measured. It was also measured the movilizable fraction and the mobile fraction, that is to say, the quantity of metals that can be taken by the roots of the plants or that it can be leached toward the water bodies. Equally, the soils of the Savanna were characterized in an area of the plane part that covers 800 km 2 , as for the physical and chemical properties that can affect the retention and mobilization of heavy metals. The results obtained shows elements, that will allow in a future to develop mobilization and transport models, adapted for our specific conditions and to make an risks evaluation for the population's health, foods consumption on these soils or for the possibility of contamination of the underground waters. The obtained data of levels of heavy metals and other properties of the soils will serve as base for future studies of the conditions of the Savanna soils and for the establishment of standard of quality in our country. During 1997 it plans to enlarge the study area to 1200 km 2 and to begin the sampling and analysis of the soils. In the first phase of the study were found levels of heavy metals that overcome the world averages especially cadmium, cobalt, nickel, lead and zinc and in some cases chromium and mercury, levels that put in evidence the existence an ecological risk and for the population

  20. Photon-counting-based diffraction phase microscopy combined with single-pixel imaging

    Science.gov (United States)

    Shibuya, Kyuki; Araki, Hiroyuki; Iwata, Tetsuo

    2018-04-01

    We propose a photon-counting (PC)-based quantitative-phase imaging (QPI) method for use in diffraction phase microscopy (DPM) that is combined with a single-pixel imaging (SPI) scheme (PC-SPI-DPM). This combination of DPM with the SPI scheme overcomes a low optical throughput problem that has occasionally prevented us from obtaining quantitative-phase images in DPM through use of a high-sensitivity single-channel photodetector such as a photomultiplier tube (PMT). The introduction of a PMT allowed us to perform PC with ease and thus solved a dynamic range problem that was inherent to SPI. As a proof-of-principle experiment, we performed a comparison study of analogue-based SPI-DPM and PC-SPI-DPM for a 125-nm-thick indium tin oxide (ITO) layer coated on a silica glass substrate. We discuss the basic performance of the method and potential future modifications of the proposed system.

  1. 100-nm thick single-phase wurtzite BAlN films with boron contents over 10%

    KAUST Repository

    Li, Xiaohang

    2017-01-11

    Growing thicker BAlN films while maintaining single-phase wurtzite structure and boron content over 10% has been challenging. In this study, we report on the growth of 100 nm-thick single-phase wurtzite BAlN films with boron contents up to 14.4% by MOCVD. Flow-modulated epitaxy was employed to increase diffusion length of group-III atoms and reduce parasitic reactions between the metalorganics and NH3. A large growth efficiency of ∼2000 μm mol−1 was achieved as a result. Small B/III ratios up to 17% in conjunction with high temperatures up to 1010 °C were utilized to prevent formation of the cubic phase and maintain wurtzite structure.

  2. 100-nm thick single-phase wurtzite BAlN films with boron contents over 10%

    KAUST Repository

    Li, Xiaohang; Wang, Shuo; Liu, Hanxiao; Ponce, Fernando A.; Detchprohm, Theeradetch; Dupuis, Russell D.

    2017-01-01

    Growing thicker BAlN films while maintaining single-phase wurtzite structure and boron content over 10% has been challenging. In this study, we report on the growth of 100 nm-thick single-phase wurtzite BAlN films with boron contents up to 14.4% by MOCVD. Flow-modulated epitaxy was employed to increase diffusion length of group-III atoms and reduce parasitic reactions between the metalorganics and NH3. A large growth efficiency of ∼2000 μm mol−1 was achieved as a result. Small B/III ratios up to 17% in conjunction with high temperatures up to 1010 °C were utilized to prevent formation of the cubic phase and maintain wurtzite structure.

  3. Phase III trial of high- vs. low-dose-rate interstitial radiotherapy for early mobile tongue cancer

    International Nuclear Information System (INIS)

    Inoue, Takehiro; Inoue, Toshihiko; Yoshida, Ken; Yoshioka, Yasuo; Shimamoto, Shigetoshi; Tanaka, Eiichi; Yamazaki, Hideya; Shimizutani, Kimishige; Teshima, Teruki; Furukawa, Souhei

    2001-01-01

    Purpose: Early mobile tongue cancer can be controlled with interstitial radiotherapy (ISRT). We carried out a Phase III trial to compare the treatment results of low-dose-rate (Ld) ISRT and high-dose-rate (HDR) ISRT for early mobile tongue cancer. Methods and Materials: From April 1992 through October 1996, 59 patients with cancer of the early mobile tongue were registered in this Phase III study. Eight patients were excluded from the evaluation because of violations of the requirements for this study. Of 51 eligible patients, 26 patients were treated with LDR-ISRT (70 Gy/4-9 days) and 25 patients with HDR-ISRT (60 Gy/10 fractions/1 week). For the hyperfractionated HDR-ISRT, the time interval between 2 fractions was more than 6 h. Results: Five-year local control rates of the LDR and HDR groups were 84% and 87% respectively. Nodal metastasis occurred in 6 patients in each group. Five-year nodal control rates of the LDR and HDR groups were 77% and 76%, respectively. Conclusion: Hyperfractionated HDR-ISRT for early mobile tongue cancer has the same local control compared with continuous LDR-ISRT. Hyperfractionated HDR-ISRT is an alternative treatment for continuous LDR-ISRT

  4. Development of a single-phase thermosiphon for cold collection and storage of radiative cooling

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Dongliang; Martini, Christine Elizabeth; Jiang, Siyu; Ma, Yaoguang; Zhai, Yao; Tan, Gang; Yin, Xiaobo; Yang, Ronggui

    2017-11-01

    A single-phase thermosiphon is developed for cold collection and storage of radiative cooling. Compared to the conventional nocturnal radiative cooling systems that use an electric pump to drive the heat transfer fluid, the proposed single-phase thermosiphon uses the buoyancy force to drive heat transfer fluid. This solution does not require electricity, therefore improving the net gain of the radiative cooling system. A single-phase thermosiphon was built, which consists of a flat panel, a cold collection tank, a water return tube, and a water distribution tank. Considering that outdoor radiative cooling flux is constantly changing (i.e. uncontrollable), an indoor testing facility was developed to provide a controllable cooling flux (comparable to a radiative cooling flux of 100 W/m2) for the evaluation of thermosiphon performance. The testing apparatus is a chilled aluminum flat plate that has a controlled air gap separation relative to the flat panel surface of the thermosiphon to emulate radiative cooling. With an average of 105 W/m2 cooling flux, the 18 liters of water in the thermosiphon was cooled to an average temperature of 12.5 degrees C from an initial temperature of 22.2 degrees C in 2 h, with a cold collection efficiency of 96.8%. The results obtained have demonstrated the feasibility of using a single-phase thermosiphon for cold collection and storage of radiative cooling. Additionally, the effects of the thermosiphon operation conditions, such as tilt angle of the flat panel, initial water temperature, and cooling energy flux, on the performance have been experimentally investigated. Modular design of the single-phase thermosiphon gives flexibility for its scalability. A radiative cooling system with multiple thermosiphon modules is expected to play an important role in cooling buildings and power plant condensers.

  5. Influence of microstructure on low cycle fatigue in some single phase and biphasic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Stolarz, J. [Ecole Nationale Superieure des Mines, Centre SMS, URA CNRS 1884, Saint-Etienne (France)

    2004-07-01

    This overview deals with the effects of microstructural parameters in different single phase and biphasic stainless steels on short crack behaviour and on fatigue life in the low cycle regime. The effect of the grain size is investigated in a single phase austenitic stainless steel. Under plastic strain control, the fatigue life increases when the grain size decreases. The results are discussed by analysing the distributions of crack depths as a function of the grain size. The second type of material is a metastable austenitic steel which partially transforms into martensite during LCF at temperatures between -50 C and +120 C. The grain size of the initially single phase austenitic microstructure has a combined influence on the volume fraction of martensite produced during fatigue and on the fatigue life. In this case, the grain size effect is still considerable but totally indirect because all fatigue cracks grow exclusively in the martensite. The cyclic behaviour analysis in biphasic alloys in which two phases undergo plastic deformation during LCF is considerably more complex because the conventional concept of microstructural barriers cannot be applied. The possible damage patterns in a pair of grains with different mechanical properties are discussed on the example of a solution treated and aged superduplex austenitic-ferritic stainless steel (SDSS). The hardening of one phase (ferrite) through ageing at 475 C changes the cyclic behaviour of the initial ''quasi single phase'' microstructure. Consequently, the fatigue life under plastic strain control decreases compared with the solution treated SDSS. The discussion is focussed on LCF damage mechanisms at the microstructure size scale with a particular accent put on the propagation of short cracks in the bulk. All the microstructures exhibit some common features with respect to the behaviour of short cracks. In particular a strong effect of microstructural barriers in the bulk and the

  6. Studies on Single-phase and Multi-phase Heat Pipe for LED Panel for Efficient Heat Dissipation

    Science.gov (United States)

    Vyshnave, K. C.; Rohit, G.; Maithreya, D. V. N. S.; Rakesh, S. G.

    2017-08-01

    The popularity of LED panel as a source of illumination has soared recently due to its high efficiency. However, the removal of heat that is produced in the chip is still a major challenge in its design since this has an adverse effect on its reliability. If high junction temperature develops, the colour of the emitted light may diminish over prolonged usage or even a colour shift may occur. In this paper, a solution has been developed to address this problem by using a combination of heat pipe and heat fin technology. A single-phase and a two-phase heat pipes have been designed theoretically and computational simulations carried out using ANSYS FLUENT. The results of the theoretical calculations and those obtained from the simulations are found to be in agreement with each other.

  7. Record mobility in transparent p-type tin monoxide films and devices by phase engineering

    KAUST Repository

    Caraveo-Frescas, Jesus Alfonso; Nayak, Pradipta K.; Al-Jawhari, Hala A.; Bianchi Granato, Danilo; Schwingenschlö gl, Udo; Alshareef, Husam N.

    2013-01-01

    developed SnO thin films with a Hall mobility of 18.71 cm2 V-1 s-1 and fabricated TFT devices with a linear field-effect mobility of 6.75 cm2 V-1 s -1 and 5.87 cm2 V-1 s-1 on transparent rigid and translucent flexible substrates, respectively. These values

  8. Automated selection of the optimal cardiac phase for single-beat coronary CT angiography reconstruction

    International Nuclear Information System (INIS)

    Stassi, D.; Ma, H.; Schmidt, T. G.; Dutta, S.; Soderman, A.; Pazzani, D.; Gros, E.; Okerlund, D.

    2016-01-01

    Purpose: Reconstructing a low-motion cardiac phase is expected to improve coronary artery visualization in coronary computed tomography angiography (CCTA) exams. This study developed an automated algorithm for selecting the optimal cardiac phase for CCTA reconstruction. The algorithm uses prospectively gated, single-beat, multiphase data made possible by wide cone-beam imaging. The proposed algorithm differs from previous approaches because the optimal phase is identified based on vessel image quality (IQ) directly, compared to previous approaches that included motion estimation and interphase processing. Because there is no processing of interphase information, the algorithm can be applied to any sampling of image phases, making it suited for prospectively gated studies where only a subset of phases are available. Methods: An automated algorithm was developed to select the optimal phase based on quantitative IQ metrics. For each reconstructed slice at each reconstructed phase, an image quality metric was calculated based on measures of circularity and edge strength of through-plane vessels. The image quality metric was aggregated across slices, while a metric of vessel-location consistency was used to ignore slices that did not contain through-plane vessels. The algorithm performance was evaluated using two observer studies. Fourteen single-beat cardiac CT exams (Revolution CT, GE Healthcare, Chalfont St. Giles, UK) reconstructed at 2% intervals were evaluated for best systolic (1), diastolic (6), or systolic and diastolic phases (7) by three readers and the algorithm. Pairwise inter-reader and reader-algorithm agreement was evaluated using the mean absolute difference (MAD) and concordance correlation coefficient (CCC) between the reader and algorithm-selected phases. A reader-consensus best phase was determined and compared to the algorithm selected phase. In cases where the algorithm and consensus best phases differed by more than 2%, IQ was scored by three

  9. Hydrodynamics of single- and two-phase flow in inclined rod arrays

    International Nuclear Information System (INIS)

    Todreas, N.E.

    1984-01-01

    Required inputs for thermal-hydraulic codes are constitutive relations for fluid-solid flow resistance, in single-phase flow, and interfacial momentum exchange (relative phase motion), in two-phase flow. An inclined rod array air-water experiment was constructed to study the hydrodynamics of multidimensional porous medium flow in rod arrays. Velocities, pressures, bubble distributions, and void fractions were measured in inline and rotational square rod arrays of P/d = 1.5, at 0, 30, 45, and 90 degree inclinations to the vertical flow direction. Constitutive models for single-phase flow resistance are reviewed, new comprehensive models developed, and an assessment with previously published and new data made. The principle of superimposing one-dimensional correlations proves successful for turbulent single-phase inclined flow. For bubbly two-phase yawed flow through incline rod arrays a new flow separation phenomena was observed and modeled. Bubbles of diameters significantly smaller than the rod diameter travel along the rod axis, while larger diameter bubbles move through the rod array gaps. The outcome is a flow separation not predictable with current interfacial momentum exchange models. This phenomenon was not observed in rotated square rod arrays. Current interfacial momentum exchange models were confirmed for this rod arrangement. Models for the two phase flow resistance multiplier for cross flow were reviewed and compared with data from cross and yawed flow rod arrays. Both drag and lift components of the multiplier were well predicted by the homogenous model. Other models reviewed overpredicted the data by a factor of two

  10. Thermal analysis of hybrid single-phase, two-phase and heat pump thermal control system (TCS) for future spacecraft

    International Nuclear Information System (INIS)

    Lee, S.H.; Mudawar, I.; Hasan, Mohammad M.

    2016-01-01

    Highlights: • Hybrid Thermal Control System (H-TCS) is proposed for future spacecraft. • Thermodynamic performance of H-TCS is examined for different space missions. • Operational modes including single-phase, two-phase and heat pump are explored. • R134a is deemed most appropriate working fluid. - Abstract: An urgent need presently exists to develop a new class of versatile spacecraft capable of conducting different types of missions and enduring varying gravitational and temperature environments, including Lunar, Martian and Near Earth Object (NEOs). This study concerns the spacecraft's Thermal Control System (TCS), which tackles heat acquisition, especially from crew and avionics, heat transport, and ultimate heat rejection by radiation. The primary goal of the study is to explore the design and thermal performance of a Hybrid Thermal Control System (H-TCS) that would satisfy the diverse thermal requirements of the different space missions. The H-TCS must endure both ‘cold’ and ‘hot’ environments, reduce weight and size, and enhance thermodynamic performance. Four different operational modes are considered: single-phase, two-phase, basic heat pump and heat pump with liquid-side, suction-side heat exchanger. A thermodynamic trade study is conducted for six different working fluids to assess important performance parameters including mass flow rate of the working fluid, maximum pressure, radiator area, compressor/pump work, and coefficient of performance (COP). R134a is determined to be most suitable based on its ability to provide a balanced compromise between reducing flow rate and maintaining low system pressure, and a moderate coefficient of performance (COP); this fluid is also both nontoxic and nonflammable, and features zero ozone depletion potential (ODP) and low global warming potential (GWP). It is shown how specific mission stages dictate which mode of operation is most suitable, and this information is used to size the radiator for the

  11. QUEUING ANALYSIS OF CAR SERVICING CUSTOMERS USED SINGLE CHANNEL MODEL AND KENDALL'S NOTATION IN PT. ARMADA MOBIL PURWOKERTO

    Directory of Open Access Journals (Sweden)

    Tugiyono

    2013-04-01

    Full Text Available This study aims to identify the customer’s problem queue, specify the model queue, the arrival and customer service frequency distributions at PT. Armada Mobil Purwokerto. Methods of the research conducted by observing and measuring directly the research object, the data from the study was calculated according to the theory of queues. The result appropriate to single channel queuing model Poisson distribution of the arrivals, exponential distribution of the time service. The characteristized of Kendall’s notation is M/M/3/3/571.

  12. Modelling by partial least squares the relationship between the HPLC mobile phases and analytes on phenyl column.

    Science.gov (United States)

    Markopoulou, Catherine K; Kouskoura, Maria G; Koundourellis, John E

    2011-06-01

    Twenty-five descriptors and 61 structurally different analytes have been used on a partial least squares (PLS) to latent structure technique in order to study chromatographically their interaction mechanism on a phenyl column. According to the model, 240 different retention times of the analytes, expressed as Y variable (log k), at different % MeOH mobile-phase concentrations have been correlated with their theoretical most important structural or molecular descriptors. The goodness-of-fit was estimated by the coefficient of multiple determinations r(2) (0.919), and the root mean square error of estimation (RMSEE=0.1283) values with a predictive ability (Q(2)) of 0.901. The model was further validated using cross-validation (CV), validated by 20 response permutations r(2) (0.0, 0.0146), Q(2) (0.0, -0.136) and validated by external prediction. The contribution of certain mechanism interactions between the analytes, the mobile phase and the column, proportional or counterbalancing is also studied. Trying to evaluate the influence on Y of every variable in a PLS model, VIP (variables importance in the projection) plot provides evidence that lipophilicity (expressed as Log D, Log P), polarizability, refractivity and the eluting power of the mobile phase are dominant in the retention mechanism on a phenyl column. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Scaling of the steady state and stability behaviour of single and two-phase natural circulation systems

    International Nuclear Information System (INIS)

    Vijayan, P.K.; Nayak, A.K.; Bade, M.H.; Kumar, N.; Saha, D.; Sinha, R.K.

    2002-01-01

    Scaling methods for both single-phase and two-phase natural circulation systems have been presented. For single-phase systems, simulation of the steady state flow can be achieved by preserving just one nondimensional parameter. For uniform diameter two-phase systems also, it is possible to simulate the steady state behaviour with just one non-dimensional parameter. Simulation of the stability behaviour requires geometric similarity in addition to the similarity of the physical parameters appearing in the governing equations. The scaling laws proposed have been tested with experimental data in case of single-phase natural circulation. (author)

  14. Position Control of the Single Spherical Wheel Mobile Robot by Using the Fuzzy Sliding Mode Controller

    Directory of Open Access Journals (Sweden)

    Hamed Navabi

    2017-01-01

    Full Text Available A spherical wheel robot or Ballbot—a robot that balances on an actuated spherical ball—is a new and recent type of robot in the popular area of mobile robotics. This paper focuses on the modeling and control of such a robot. We apply the Lagrangian method to derive the governing dynamic equations of the system. We also describe a novel Fuzzy Sliding Mode Controller (FSMC implemented to control a spherical wheel mobile robot. The nonlinear nature of the equations makes the controller nontrivial. We compare the performance of four different fuzzy controllers: (a regulation with one signal, (b regulation and position control with one signal, (c regulation and position control with two signals, and (d FSMC for regulation and position control with two signals. The system is evaluated in a realistic simulation and the robot parameters are chosen based on a LEGO platform, so the designed controllers have the ability to be implemented on real hardware.

  15. Optical π phase shift created with a single-photon pulse.

    Science.gov (United States)

    Tiarks, Daniel; Schmidt, Steffen; Rempe, Gerhard; Dürr, Stephan

    2016-04-01

    A deterministic photon-photon quantum logic gate is a long-standing goal. Building such a gate becomes possible if a light pulse containing only one photon imprints a phase shift of π onto another light field. We experimentally demonstrate the generation of such a π phase shift with a single-photon pulse. A first light pulse containing less than one photon on average is stored in an atomic gas. Rydberg blockade combined with electromagnetically induced transparency creates a phase shift for a second light pulse, which propagates through the medium. We measure the π phase shift of the second pulse when we postselect the data upon the detection of a retrieved photon from the first pulse. This demonstrates a crucial step toward a photon-photon gate and offers a variety of applications in the field of quantum information processing.

  16. Phase locking of a semiconductor double-quantum-dot single-atom maser

    Science.gov (United States)

    Liu, Y.-Y.; Hartke, T. R.; Stehlik, J.; Petta, J. R.

    2017-11-01

    We experimentally study the phase stabilization of a semiconductor double-quantum-dot (DQD) single-atom maser by injection locking. A voltage-biased DQD serves as an electrically tunable microwave frequency gain medium. The statistics of the maser output field demonstrate that the maser can be phase locked to an external cavity drive, with a resulting phase noise L =-99 dBc/Hz at a frequency offset of 1.3 MHz. The injection locking range, and the phase of the maser output relative to the injection locking input tone are in good agreement with Adler's theory. Furthermore, the electrically tunable DQD energy level structure allows us to rapidly switch the gain medium on and off, resulting in an emission spectrum that resembles a frequency comb. The free running frequency comb linewidth is ≈8 kHz and can be improved to less than 1 Hz by operating the comb in the injection locked regime.

  17. Rapid synthesis of single-phase bismuth ferrite by microwave-assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Wenqian [College of Materials Science and Engineering, China Jiliang University, 258 Xueyuan Street, Xiasha Higher Education District, Hangzhou 310018, Zhejiang Province (China); Chen, Zhi, E-mail: zchen0@gmail.com [College of Materials Science and Engineering, China Jiliang University, 258 Xueyuan Street, Xiasha Higher Education District, Hangzhou 310018, Zhejiang Province (China); Gao, Tong; Zhou, Dantong; Leng, Xiaonan; Niu, Feng [College of Materials Science and Engineering, China Jiliang University, 258 Xueyuan Street, Xiasha Higher Education District, Hangzhou 310018, Zhejiang Province (China); Zhu, Yuxiang [College of Materials Science and Engineering, China Jiliang University, 258 Xueyuan Street, Xiasha Higher Education District, Hangzhou 310018, Zhejiang Province (China); Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin University of Science and Technology, Tianjin (China); Qin, Laishun, E-mail: qinlaishun@yeah.net [College of Materials Science and Engineering, China Jiliang University, 258 Xueyuan Street, Xiasha Higher Education District, Hangzhou 310018, Zhejiang Province (China); Wang, Jiangying; Huang, Yuexiang [College of Materials Science and Engineering, China Jiliang University, 258 Xueyuan Street, Xiasha Higher Education District, Hangzhou 310018, Zhejiang Province (China)

    2016-06-01

    This paper describes on the fast synthesis of bismuth ferrite by the simple microwave-assisted hydrothermal method. The phase transformation and the preferred growth facets during the synthetic process have been investigated by X-ray diffraction. Bismuth ferrite can be quickly prepared by microwave hydrothermal method by simply controlling the reaction time, which is further confirmed by Fourier Transform infrared spectroscopy and magnetic measurement. - Graphical abstract: Single-phase BiFeO{sub 3} could be realized at a shortest reaction time of 65 min. The reaction time has strong influences on the phase transformation and the preferred growth facets. - Highlights: • Rapid synthesis (65 min) of BiFeO{sub 3} by microwave-assisted hydrothermal method. • Reaction time has influence on the purity and preferred growth facets. • FTIR and magnetic measurement further confirm the pure phase.

  18. Single-reactor process for producing liquid-phase organic compounds from biomass

    Science.gov (United States)

    Dumesic, James A [Verona, WI; Simonetti, Dante A [Middleton, WI; Kunkes, Edward L [Madison, WI

    2011-12-13

    Disclosed is a method for preparing liquid fuel and chemical intermediates from biomass-derived oxygenated hydrocarbons. The method includes the steps of reacting in a single reactor an aqueous solution of a biomass-derived, water-soluble oxygenated hydrocarbon reactant, in the presence of a catalyst comprising a metal selected from the group consisting of Cr, Mn, Fe, Co, Ni, Cu, Mo, Tc, Ru, Rh, Pd, Ag, W, Re, Os, Ir, Pt, and Au, at a temperature, and a pressure, and for a time sufficient to yield a self-separating, three-phase product stream comprising a vapor phase, an organic phase containing linear and/or cyclic mono-oxygenated hydrocarbons, and an aqueous phase.

  19. Rapid synthesis of single-phase bismuth ferrite by microwave-assisted hydrothermal method

    International Nuclear Information System (INIS)

    Cao, Wenqian; Chen, Zhi; Gao, Tong; Zhou, Dantong; Leng, Xiaonan; Niu, Feng; Zhu, Yuxiang; Qin, Laishun; Wang, Jiangying; Huang, Yuexiang

    2016-01-01

    This paper describes on the fast synthesis of bismuth ferrite by the simple microwave-assisted hydrothermal method. The phase transformation and the preferred growth facets during the synthetic process have been investigated by X-ray diffraction. Bismuth ferrite can be quickly prepared by microwave hydrothermal method by simply controlling the reaction time, which is further confirmed by Fourier Transform infrared spectroscopy and magnetic measurement. - Graphical abstract: Single-phase BiFeO_3 could be realized at a shortest reaction time of 65 min. The reaction time has strong influences on the phase transformation and the preferred growth facets. - Highlights: • Rapid synthesis (65 min) of BiFeO_3 by microwave-assisted hydrothermal method. • Reaction time has influence on the purity and preferred growth facets. • FTIR and magnetic measurement further confirm the pure phase.

  20. Single-Cycle Terahertz Pulse Generation from OH1 Crystal via Cherenkov Phase Matching

    Science.gov (United States)

    Uchida, Hirohisa; Oota, Kengo; Okimura, Koutarou; Kawase, Kodo; Takeya, Kei

    2018-06-01

    OH1 crystal is an organic nonlinear optical crystal with a large nonlinear optical constant. However, it has dispersion of refractive indices in the terahertz (THz) frequency. This limits the frequencies that satisfy the phase matching conditions for THz wave generation. In this study, we addressed the phase matching conditions for THz wave generation by combining an OH1 crystal with prism-coupled Cherenkov phase matching. We observed the generation of single-cycle THz pulses with a spectrum covering a frequency range of 3 THz. These results prove that combining prism-coupled Cherenkov phase matching with nonlinear optical crystals yields a THz wave generation method that is insusceptible to crystal dispersion.

  1. Investigation on phase noise of the signal from a singly resonant optical parametric oscillator

    Science.gov (United States)

    Jinxia, Feng; Yuanji, Li; Kuanshou, Zhang

    2018-04-01

    The phase noise of the signal from a singly resonant optical parametric oscillator (SRO) is investigated theoretically and experimentally. An SRO based on periodically poled lithium niobate is built up that generates the signal with a maximum power of 5.2 W at 1.5 µm. The intensity noise of the signal reaches the shot noise level for frequencies above 5 MHz. The phase noise of the signal oscillates depending on the analysis frequency, and there are phase noise peaks above the shot noise level at the peak frequencies. To explain the phase noise feature of the signal, a semi-classical theoretical model of SROs including the guided acoustic wave Brillouin scattering effect within the nonlinear crystal is developed. The theoretical predictions are in good agreement with the experimental results.

  2. Size and molecular weight determination of polysaccharides by means of nano electrospray gas-phase electrophoretic mobility molecular analysis (nES GEMMA).

    Science.gov (United States)

    Weiss, Victor U; Golesne, Monika; Friedbacher, Gernot; Alban, Susanne; Szymanski, Wladyslaw W; Marchetti-Deschmann, Martina; Allmaier, Günter

    2018-02-21

    Size, size distribution and molecular weight (MW) determination of nanoparticles and that are for example large polymers, are of great interest and pose an analytical challenge. In this context, nano electrospray gas-phase electrophoretic mobility molecular analysis (nES GEMMA) is a valuable tool with growing impact. Separation of single-charged analytes according to their electrophoretic mobility diameter (EMD) starting from single-digit EMDs up to several hundred nm diameters is possible. In case of spherical analytes, the EMD corresponds to the dry nanoparticle size. Additionally, the instrument is capable of number-based, single-particle detection following the recommendation of the European Commission for nanoparticle characterization (2011/696/EU). In case an EMD/MW correlation for a particular compound class (based on availability of well-defined standards) exists, a nanoparticle's MW can be determined from its EMD. In the present study, we focused on nES GEMMA of linear and branched, water-soluble polysaccharides forming nanoparticles and were able to obtain spectra for both analyte classes regarding single-charged species. Based on EMDs for corresponding analytes, an excellent EMD/MW correlation could be obtained in case of the branched natural polymer (dextran). This enables the determination of dextran MWs from nES GEMMA spectra despite high analyte polydispersity and in a size/MW range, where classical mass spectrometry is limited. EMD/MW correlations based on linear (pullulans, oat-ß-glucans) polymers were significantly different, possibly indicating challenges in the exact MW determination of these compounds by, for example, chromatographic and light scattering means. Despite these observations, nES GEMMA of linear, monosaccharide-based polymers enabled the determination of size and size-distribution of such dry bionanoparticles. © 2018 The Authors. Electrophoresis published by Wiley-VCH Verlag GmbH & Co. KGaA.

  3. Optimal multi-photon phase sensing with a single interference fringe

    Science.gov (United States)

    Xiang, G. Y.; Hofmann, H. F.; Pryde, G. J.

    2013-01-01

    Quantum entanglement can help to increase the precision of optical phase measurements beyond the shot noise limit (SNL) to the ultimate Heisenberg limit. However, the N-photon parity measurements required to achieve this optimal sensitivity are extremely difficult to realize with current photon detection technologies, requiring high-fidelity resolution of N + 1 different photon distributions between the output ports. Recent experimental demonstrations of precision beyond the SNL have therefore used only one or two photon-number detection patterns instead of parity measurements. Here we investigate the achievable phase sensitivity of the simple and efficient single interference fringe detection technique. We show that the maximally-entangled “NOON” state does not achieve optimal phase sensitivity when N > 4, rather, we show that the Holland-Burnett state is optimal. We experimentally demonstrate this enhanced sensitivity using a single photon-counted fringe of the six-photon Holland-Burnett state. Specifically, our single-fringe six-photon measurement achieves a phase variance three times below the SNL. PMID:24067490

  4. Non-Resonant Magnetoelectric Energy Harvesting Utilizing Phase Transformation in Relaxor Ferroelectric Single Crystals

    Directory of Open Access Journals (Sweden)

    Peter Finkel

    2015-12-01

    Full Text Available Recent advances in phase transition transduction enabled the design of a non-resonant broadband mechanical energy harvester that is capable of delivering an energy density per cycle up to two orders of magnitude larger than resonant cantilever piezoelectric type generators. This was achieved in a [011] oriented and poled domain engineered relaxor ferroelectric single crystal, mechanically biased to a state just below the ferroelectric rhombohedral (FR-ferroelectric orthorhombic (FO phase transformation. Therefore, a small variation in an input parameter, e.g., electrical, mechanical, or thermal will generate a large output due to the significant polarization change associated with the transition. This idea was extended in the present work to design a non-resonant, multi-domain magnetoelectric composite hybrid harvester comprised of highly magnetostrictive alloy, [Fe81.4Ga18.6 (Galfenol or TbxDy1-xFe2 (Terfenol-D], and lead indium niobate–lead magnesium niobate–lead titanate (PIN-PMN-PT domain engineered relaxor ferroelectric single crystal. A small magnetic field applied to the coupled device causes the magnetostrictive element to expand, and the resulting stress forces the phase change in the relaxor ferroelectric single crystal. We have demonstrated high energy conversion in this magnetoelectric device by triggering the FR-FO transition in the single crystal by a small ac magnetic field in a broad frequency range that is important for multi-domain hybrid energy harvesting devices.

  5. Characterization of Eag1 channel lateral mobility in rat hippocampal cultures by single-particle-tracking with quantum dots.

    Directory of Open Access Journals (Sweden)

    David Gómez-Varela

    2010-01-01

    Full Text Available Voltage-gated ion channels are main players involved in fast synaptic events. However, only slow intracellular mechanisms have so far been described for controlling their localization as real-time visualization of endogenous voltage-gated channels at high temporal and spatial resolution has not been achieved yet. Using a specific extracellular antibody and quantum dots we reveal and characterize lateral mobility as a faster mechanism to dynamically control the number of endogenous ether-a-go-go (Eag1 ion channels inside synapses. We visualize Eag1 entering and leaving synapses by lateral diffusion in the plasma membrane of rat hippocampal neurons. Mathematical analysis of their trajectories revealed how the motion of Eag1 gets restricted when the channels diffuse into the synapse, suggesting molecular interactions between Eag1 and synaptic components. In contrast, Eag1 channels switch to Brownian movement when they exit synapses and diffuse into extrasynaptic membranes. Furthermore, we demonstrate that the mobility of Eag1 channels is specifically regulated inside synapses by actin filaments, microtubules and electrical activity. In summary, using single-particle-tracking techniques with quantum dots nanocrystals, our study shows for the first time the lateral diffusion of an endogenous voltage-gated ion channel in neurons. The location-dependent constraints imposed by cytoskeletal elements together with the regulatory role of electrical activity strongly suggest a pivotal role for the mobility of voltage-gated ion channels in synaptic activity.

  6. Single-image phase retrieval using an edge illumination X-ray phase-contrast imaging setup

    Energy Technology Data Exchange (ETDEWEB)

    Diemoz, Paul C., E-mail: p.diemoz@ucl.ac.uk; Vittoria, Fabio A. [University College London, London WC1 E6BT (United Kingdom); Research Complex at Harwell, Oxford Harwell Campus, Didcot OX11 0FA (United Kingdom); Hagen, Charlotte K.; Endrizzi, Marco [University College London, London WC1 E6BT (United Kingdom); Coan, Paola [Ludwig-Maximilians-University, Munich 81377 (Germany); Ludwig-Maximilians-University, Garching 85748 (Germany); Brun, Emmanuel [Ludwig-Maximilians-University, Garching 85748 (Germany); European Synchrotron Radiation Facility, Grenoble 38043 (France); Wagner, Ulrich H.; Rau, Christoph [Diamond Light Source, Harwell Oxford Campus, Didcot OX11 0DE (United Kingdom); Robinson, Ian K. [Research Complex at Harwell, Oxford Harwell Campus, Didcot OX11 0FA (United Kingdom); London Centre for Nanotechnology, London WC1 H0AH (United Kingdom); Bravin, Alberto [European Synchrotron Radiation Facility, Grenoble 38043 (France); Olivo, Alessandro [University College London, London WC1 E6BT (United Kingdom); Research Complex at Harwell, Oxford Harwell Campus, Didcot OX11 0FA (United Kingdom)

    2015-06-25

    A method enabling the retrieval of thickness or projected electron density of a sample from a single input image is derived theoretically and successfully demonstrated on experimental data. A method is proposed which enables the retrieval of the thickness or of the projected electron density of a sample from a single input image acquired with an edge illumination phase-contrast imaging setup. The method assumes the case of a quasi-homogeneous sample, i.e. a sample with a constant ratio between the real and imaginary parts of its complex refractive index. Compared with current methods based on combining two edge illumination images acquired in different configurations of the setup, this new approach presents advantages in terms of simplicity of acquisition procedure and shorter data collection time, which are very important especially for applications such as computed tomography and dynamical imaging. Furthermore, the fact that phase information is directly extracted, instead of its derivative, can enable a simpler image interpretation and be beneficial for subsequent processing such as segmentation. The method is first theoretically derived and its conditions of applicability defined. Quantitative accuracy in the case of homogeneous objects as well as enhanced image quality for the imaging of complex biological samples are demonstrated through experiments at two synchrotron radiation facilities. The large range of applicability, the robustness against noise and the need for only one input image suggest a high potential for investigations in various research subjects.

  7. Phase transition sequence in ferroelectric Aurivillius compounds investigated by single crystal X-ray diffraction

    Science.gov (United States)

    Boullay, P.; Tellier, J.; Mercurio, D.; Manier, M.; Zuñiga, F. J.; Perez-Mato, J. M.

    2012-09-01

    The investigation of the phase transition sequence in SrBi2Ta2O9 (SBT) and SrBi2Nb2O9 (SBN) is reported using single-crystal X-ray diffraction. By monitoring specific reflections as a function of temperature, sensitive either to the superstructure formation or to polar displacements, it was possible to check the existence or not of an intermediate phase. This latter was confirmed in SBT, but within experimental accuracy could not be detected in SBN.

  8. Reaction kinetics of oxygen on single-phase alloys, oxidation of nickel and niobium alloys

    International Nuclear Information System (INIS)

    Lalauze, Rene

    1973-01-01

    This research thesis first addresses the reaction kinetics of oxygen on alloys. It presents some generalities on heterogeneous reactions (conventional theory, theory of jumps), discusses the core reaction (with the influence of pressure), discusses the influence of metal self-diffusion on metal oxidation kinetics (equilibrium conditions at the interface, hybrid diffusion regime), reports the application of the hybrid diffusion model to the study of selective oxidation of alloys (Wagner model, hybrid diffusion model) and the study of the oxidation kinetics of an alloy forming a solid solution of two oxides. The second part reports the investigation of the oxidation of single phase nickel and niobium alloys (phase α, β and γ)

  9. Dispersed single-phase-step Michelson interferometer for Doppler imaging using sunlight.

    Science.gov (United States)

    Wan, Xiaoke; Ge, Jian

    2012-09-15

    A Michelson interferometer is dispersed with a fiber array-fed spectrograph, providing 59 Doppler sensing channels using sunlight in the 510-570 nm wavelength region. The interferometer operates at a single-phase-step mode, which is particularly advantageous in multiplexing and data processing compared to the phase-stepping mode of other interferometer spectrometer instruments. Spectral templates are prepared using a standard solar spectrum and simulated interferometer modulations, such that the correlation function with a measured 1D spectrum determines the Doppler shift. Doppler imaging of a rotating cylinder is demonstrated. The average Doppler sensitivity is ~12 m/s, with some channels reaching ~5 m/s.

  10. Benchmarking of small-signal dynamics of single-phase PLLs

    DEFF Research Database (Denmark)

    Zhang, Chong; Wang, Xiongfei; Blaabjerg, Frede

    2015-01-01

    Phase-looked Loop (PLL) is a critical component for the control and grid synchronization of grid-connected power converters. This paper presents a benchmarking study on the small-signal dynamics of three commonly used PLLs for single-phase converters, including enhanced PLL, second......-order generalized integrator based PLL, and the inverse-PLL. First, a unified small-signal model of those PLLs is established for comparing their dynamics. Then, a systematic design guideline for parameters tuning of the PLLs is formulated. To confirm the validity of theoretical analysis, nonlinear time...

  11. Comparing Multipollutant Emissions-Based Mobile Source Indicators to Other Single Pollutant and Multipollutant Indicators in Different Urban Areas

    Directory of Open Access Journals (Sweden)

    Michelle M. Oakes

    2014-11-01

    Full Text Available A variety of single pollutant and multipollutant metrics can be used to represent exposure to traffic pollutant mixtures and evaluate their health effects. Integrated mobile source indicators (IMSIs that combine air quality concentration and emissions data have recently been developed and evaluated using data from Atlanta, Georgia. IMSIs were found to track trends in traffic-related pollutants and have similar or stronger associations with health outcomes. In the current work, we apply IMSIs for gasoline, diesel and total (gasoline + diesel vehicles to two other cities (Denver, Colorado and Houston, Texas with different emissions profiles as well as to a different dataset from Atlanta. We compare spatial and temporal variability of IMSIs to single-pollutant indicators (carbon monoxide (CO, nitrogen oxides (NOx and elemental carbon (EC and multipollutant source apportionment factors produced by Positive Matrix Factorization (PMF. Across cities, PMF-derived and IMSI gasoline metrics were most strongly correlated with CO (r = 0.31–0.98, while multipollutant diesel metrics were most strongly correlated with EC (r = 0.80–0.98. NOx correlations with PMF factors varied across cities (r = 0.29–0.67, while correlations with IMSIs were relatively consistent (r = 0.61–0.94. In general, single-pollutant metrics were more correlated with IMSIs (r = 0.58–0.98 than with PMF-derived factors (r = 0.07–0.99. A spatial analysis indicated that IMSIs were more strongly correlated (r > 0.7 between two sites in each city than single pollutant and PMF factors. These findings provide confidence that IMSIs provide a transferable, simple approach to estimate mobile source air pollution in cities with differing topography and source profiles using readily available data.

  12. State-Space Equations and the First-Phase Algorithm for Signal Control of Single Intersections

    Institute of Scientific and Technical Information of China (English)

    LI Jinyuan; PAN Xin; WANG Xiqin

    2007-01-01

    State-space equations were applied to formulate the queuing and delay of traffic at a single intersection in this paper. The signal control of a single intersection was then modeled as a discrete-time optimal control problem, with consideration of the constraints of stream conflicts, saturation flow rate, minimum green time, and maximum green time. The problem cannot be solved directly due to the nonlinear constraints.However, the results of qualitative analysis were used to develop a first-phase signal control algorithm. Simulation results show that the algorithm substantially reduces the total delay compared to fixed-time control.

  13. Self-phase modulation of a single-cycle THz pulse

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, M. C.

    2013-01-01

    We demonstrate self-phase modulation (SPM) of a single-cycle THz pulse in a semiconductor, using bulk n-GaAs as a model system. The SPM arises from the heating of free electrons in the electric field of the THz pulse. Electron heating leads to an ultrafast reduction of the plasma frequency, which...... results in a strong modification of the THz-range dielectric function of the material. THz SPM is observed directly in the time domain as a characteristic reshaping of single-cycle THz pulse. In the frequency domain, it corresponds to a strong frequency-dependent refractive index nonlinearity of n...

  14. Balancing the costs of mobility investments in work zones : phase 1 final report.

    Science.gov (United States)

    2015-06-01

    Work zone safety and mobility continue to be critical transportation concerns in Michigan and elsewhere. : Previous research has led to the development of a variety of tools, performance measures and decision-making frameworks to analyze work zone sa...

  15. Single-phase and two-phase anaerobic digestion of fruit and vegetable waste: Comparison of start-up, reactor stability and process performance

    International Nuclear Information System (INIS)

    Ganesh, Rangaraj; Torrijos, Michel; Sousbie, Philippe; Lugardon, Aurelien; Steyer, Jean Philippe; Delgenes, Jean Philippe

    2014-01-01

    Highlights: • Single-phase and two-phase systems were compared for fruit and vegetable waste digestion. • Single-phase digestion produced a methane yield of 0.45 m 3 CH 4 /kg VS and 83% VS removal. • Substrate solubilization was high in acidification conditions at 7.0 kg VS/m 3 d and pH 5.5–6.2. • Energy yield was lower by 33% for two-phase system compared to the single-phase system. • Simple and straight-forward operation favored single phase process over two-phase process. - Abstract: Single-phase and two-phase digestion of fruit and vegetable waste were studied to compare reactor start-up, reactor stability and performance (methane yield, volatile solids reduction and energy yield). The single-phase reactor (SPR) was a conventional reactor operated at a low loading rate (maximum of 3.5 kg VS/m 3 d), while the two-phase system consisted of an acidification reactor (TPAR) and a methanogenic reactor (TPMR). The TPAR was inoculated with methanogenic sludge similar to the SPR, but was operated with step-wise increase in the loading rate and with total recirculation of reactor solids to convert it into acidification sludge. Before each feeding, part of the sludge from TPAR was centrifuged, the centrifuge liquid (solubilized products) was fed to the TPMR and centrifuged solids were recycled back to the reactor. Single-phase digestion produced a methane yield of 0.45 m 3 CH 4 /kg VS fed and VS removal of 83%. The TPAR shifted to acidification mode at an OLR of 10.0 kg VS/m 3 d and then achieved stable performance at 7.0 kg VS/m 3 d and pH 5.5–6.2, with very high substrate solubilization rate and a methane yield of 0.30 m 3 CH 4 /kg COD fed. The two-phase process was capable of high VS reduction, but material and energy balance showed that the single-phase process was superior in terms of volumetric methane production and energy yield by 33%. The lower energy yield of the two-phase system was due to the loss of energy during hydrolysis in the TPAR and the

  16. Phase out Mobile Communication Technology: An Analysis Based on Public Policy and Business Values

    OpenAIRE

    Huang, Kuang-Chiu; Houng, Ming-Wie

    2017-01-01

    Through the progress of communication technology, the mobile services have broughtlots of benefits for our daily lives. However, with the recent advances in cellular communications and new systems being deployed alongside existing ones, an emerging question aboutwhether there still is someneedsfor the legacy infrastructure, in particular the widely deployed GSMsystemsat this moment.Forthe evolution of mobile communication, we have embrace convenience and efficiency offered bymobile service.We...

  17. Analysis of single quantum-dot mobility inside 1D nanochannel devices

    Science.gov (United States)

    Hoang, H. T.; Segers-Nolten, I. M.; Tas, N. R.; van Honschoten, J. W.; Subramaniam, V.; Elwenspoek, M. C.

    2011-07-01

    We visualized individual quantum dots using a combination of a confining nanochannel and an ultra-sensitive microscope system, equipped with a high numerical aperture lens and a highly sensitive camera. The diffusion coefficients of the confined quantum dots were determined from the experimentally recorded trajectories according to the classical diffusion theory for Brownian motion in two dimensions. The calculated diffusion coefficients were three times smaller than those in bulk solution. These observations confirm and extend the results of Eichmann et al (2008 Langmuir 24 714-21) to smaller particle diameters and more narrow confinement. A detailed analysis shows that the observed reduction in mobility cannot be explained by conventional hydrodynamic theory.

  18. Analysis of single quantum-dot mobility inside 1D nanochannel devices

    International Nuclear Information System (INIS)

    Hoang, H T; Tas, N R; Van Honschoten, J W; Elwenspoek, M C; Segers-Nolten, I M; Subramaniam, V

    2011-01-01

    We visualized individual quantum dots using a combination of a confining nanochannel and an ultra-sensitive microscope system, equipped with a high numerical aperture lens and a highly sensitive camera. The diffusion coefficients of the confined quantum dots were determined from the experimentally recorded trajectories according to the classical diffusion theory for Brownian motion in two dimensions. The calculated diffusion coefficients were three times smaller than those in bulk solution. These observations confirm and extend the results of Eichmann et al (2008 Langmuir 24 714-21) to smaller particle diameters and more narrow confinement. A detailed analysis shows that the observed reduction in mobility cannot be explained by conventional hydrodynamic theory.

  19. Assessing the measurement of aerosol single scattering albedo by Cavity Attenuated Phase-Shift Single Scattering Monitor (CAPS PMssa)

    Science.gov (United States)

    Perim de Faria, Julia; Bundke, Ulrich; Onasch, Timothy B.; Freedman, Andrew; Petzold, Andreas

    2016-04-01

    The necessity to quantify the direct impact of aerosol particles on climate forcing is already well known; assessing this impact requires continuous and systematic measurements of the aerosol optical properties. Two of the main parameters that need to be accurately measured are the aerosol optical depth and single scattering albedo (SSA, defined as the ratio of particulate scattering to extinction). The measurement of single scattering albedo commonly involves the measurement of two optical parameters, the scattering and the absorption coefficients. Although there are well established technologies to measure both of these parameters, the use of two separate instruments with different principles and uncertainties represents potential sources of significant errors and biases. Based on the recently developed cavity attenuated phase shift particle extinction monitor (CAPS PM_{ex) instrument, the CAPS PM_{ssa instrument combines the CAPS technology to measure particle extinction with an integrating sphere capable of simultaneously measuring the scattering coefficient of the same sample. The scattering channel is calibrated to the extinction channel, such that the accuracy of the single scattering albedo measurement is only a function of the accuracy of the extinction measurement and the nephelometer truncation losses. This gives the instrument an accurate and direct measurement of the single scattering albedo. In this study, we assess the measurements of both the extinction and scattering channels of the CAPS PM_{ssa through intercomparisons with Mie theory, as a fundamental comparison, and with proven technologies, such as integrating nephelometers and filter-based absorption monitors. For comparison, we use two nephelometers, a TSI 3563 and an Aurora 4000, and two measurements of the absorption coefficient, using a Particulate Soot Absorption Photometer (PSAP) and a Multi Angle Absorption Photometer (MAAP). We also assess the indirect absorption coefficient

  20. Creep in single crystals of γ single phase Ni-20Cr alloy and evolution of dynamic recrystallization

    International Nuclear Information System (INIS)

    Matsuo, T.; Terada, Y.; Takahashi, S.; Ishiwari, Y.

    2000-01-01

    The creep rate - time and the creep rate - strain curves of the single crystals of γ single phase Ni-20 mass%Cr alloy have been investigated at 1173 K under the wide stress range of 19.6 to 98 MPa, and compared with those of polycrystals. The orientation corresponding to the stress axis of the single crystals were chosen within the standard stereographic triangle. The creep curve in the Ni-20 mass%Cr single crystal consists of a transient stage and an accelerating stage without a steady state stage. The transient stage has two steps. In the first step, the creep rate slightly decreases, and in the second step, the decrease in creep rate becomes prominent with increasing the testing time. With decreasing the stress, the extension of transient stage becomes prominent, and by this extension, the decreasing ratio of the creep rate in transient stage is enlarged. At the lowest stress of 19.6 MPa, the most prominent extension of transient stage and the more than two order decrease in creep rate in transient stage are detected. The creep interrupting tests have been conducted at the stress of 29.4 MPa in the strain range of 0.1 to 0.6 to examine the appearance of dynamically recrystallized grains. At the strain of 0.1 corresponding to the end of the first step in transient stage, a straight subboundary parallel to slip plane appears in a wide distance of a few hundreds micrometers. With increasing the strain, the straight subboundary turns to waved one. At the strain showing the minimum creep rate, a lot of evolved subgrains appear. At the strain corresponding to the early stage of accelerating creep, dynamically recrystallized grains appear. It is confirmed that the onset of accelerating creep well corresponds to the appearance of dynamically recrystallized grains. In the single crystal creep ruptured, the whole gage portion turns to polycrystal with equiaxed grains having a diameter of 150 μm. (orig.)

  1. A New Power Calculation Method for Single-Phase Grid-Connected Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede

    2013-01-01

    A new method to calculate average active power and reactive power for single-phase systems is proposed in this paper. It can be used in different applications where the output active power and reactive power need to be calculated accurately and fast. For example, a grid-connected photovoltaic...... system in low voltage ride through operation mode requires a power feedback for the power control loop. Commonly, a Discrete Fourier Transform (DFT) based power calculation method can be adopted in such systems. However, the DFT method introduces at least a one-cycle time delay. The new power calculation...... method, which is based on the adaptive filtering technique, can achieve a faster response. The performance of the proposed method is verified by experiments and demonstrated in a 1 kW single-phase grid-connected system operating under different conditions.Experimental results show the effectiveness...

  2. Fourier phase retrieval with a single mask by Douglas-Rachford algorithms.

    Science.gov (United States)

    Chen, Pengwen; Fannjiang, Albert

    2018-05-01

    The Fourier-domain Douglas-Rachford (FDR) algorithm is analyzed for phase retrieval with a single random mask. Since the uniqueness of phase retrieval solution requires more than a single oversampled coded diffraction pattern, the extra information is imposed in either of the following forms: 1) the sector condition on the object; 2) another oversampled diffraction pattern, coded or uncoded. For both settings, the uniqueness of projected fixed point is proved and for setting 2) the local, geometric convergence is derived with a rate given by a spectral gap condition. Numerical experiments demonstrate global, power-law convergence of FDR from arbitrary initialization for both settings as well as for 3 or more coded diffraction patterns without oversampling. In practice, the geometric convergence can be recovered from the power-law regime by a simple projection trick, resulting in highly accurate reconstruction from generic initialization.

  3. Stability analysis of single-phase thermosyphon loops by finite difference numerical methods

    International Nuclear Information System (INIS)

    Ambrosini, W.

    1998-01-01

    In this paper, examples of the application of finite difference numerical methods in the analysis of stability of single-phase natural circulation loops are reported. The problem is here addressed for its relevance for thermal-hydraulic system code applications, in the aim to point out the effect of truncation error on stability prediction. The methodology adopted for analysing in a systematic way the effect of various finite difference discretization can be considered the numerical analogue of the usual techniques adopted for PDE stability analysis. Three different single-phase loop configurations are considered involving various kinds of boundary conditions. In one of these cases, an original dimensionless form of the governing equations is proposed, adopting the Reynolds number as a flow variable. This allows for an appropriate consideration of transition between laminar and turbulent regimes, which is not possible with other dimensionless forms, thus enlarging the field of validity of model assumptions. (author). 14 refs., 8 figs

  4. Microcontroller Based SPWM Single-Phase Inverter For Wind Power Application

    Directory of Open Access Journals (Sweden)

    Khin Ohmar Lin

    2017-04-01

    Full Text Available In this paper microcontroller based sinusoidal pulse width modulation SPWM single-phase inverter is emphasized to constant frequency conversion scheme for wind power application. The wind-power generator output voltage and frequency are fluctuated due to the variation of wind velocity. Therefore the AC output voltage of wind-generator is converted into DC voltage by using rectifier circuit and this DC voltage is converted back to AC voltage by using inverter circuit. SPWM technique is used in inverter to get nearly sine wave and reduce harmonic content. The rating of inverter is 500W single-phase 220V 50 Hz. The required SPWM timing pulses for the inverter are generated from the PIC16F877A microcontroller. Circuit simulation was done by using Proteus 7 Professional and MATLABR 2008 software. The software for microcontroller is implemented by using MPASM assembler.

  5. Improved Design Methods for Robust Single- and Three-Phase ac-dc-ac Power Converters

    DEFF Research Database (Denmark)

    Qin, Zian

    . The approaches for improving their performance, in terms of the voltage stress, efficiency, power density, cost, loss distribution, and temperature, will be studied. The structure of the thesis is as follows, Chapter 1 presents the introduction and motivation of the whole project as well as the background...... becomes a emerging challenge. Accordingly, installation of sustainable power generators like wind turbines and solar panels has experienced a large increase during the last decades. Meanwhile, power electronics converters, as interfaces in electrical system, are delivering approximately 80 % electricity...... back-to-back, and meanwhile improve the harmonics, control flexibility, and thermal distribution between the switches. Afterwards, active power decoupling methods for single-phase inverters or rectifiers that are similar to the single-phase ac-dc-ac converter, are studied in Chapter 4...

  6. A High Power Density Single-Phase PWM Rectifier With Active Ripple Energy Storage

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ruxi [Virginia Polytechnic Institute and State University (Virginia Tech); Wang, Fei [ORNL; Boroyevich, Dushan [Virginia Polytechnic Institute and State University (Virginia Tech); Burgos, Rolando [ABB; Lai, Rixin [General Electric; Ning, Puqi [ORNL; Rajashekara, Kaushik [Rolls Royce

    2011-01-01

    It is well known that single-phase pulse width modulation rectifiers have second-order harmonic currents and corresponding ripple voltages on the dc bus. The low-frequency harmonic current is normally filtered using a bulk capacitor in the bus, which results in low power density. However, pursuing high power density in converter design is a very important goal in the aerospace applications. This paper studies methods for reducing the energy storage capacitor for single-phase rectifiers. The minimum ripple energy storage requirement is derived independently of a specific topology. Based on theminimum ripple energy requirement, the feasibility of the active capacitor s reduction schemes is verified. Then, we propose a bidirectional buck boost converter as the ripple energy storage circuit, which can effectively reduce the energy storage capacitance. The analysis and design are validated by simulation and experimental results.

  7. Experimental research on single phase convection heat transfer in micro-fin tube

    International Nuclear Information System (INIS)

    Fan Guangming; Sun Zhongning; Zhu Sheng

    2011-01-01

    An experimental investigation of heat transfer and flow resistance characteristics of single phase water in three micro-fin tubes with different fin height was conducted. At the same time, the efficiency of micro-fin tubes within the experimental scope was evaluated and the optimal working region was determined. Based on the experimental data in the optimal working region, correlations for predicting the heat transfer and flow resistance were also given by multiple regression method. The result indicates that the micro-fin tubes can greatly enhance the single-phase heat transfer in turbulent flow, and the increase of heat transfer coefficient is higher than the increase of flow resistance. The accuracy of the correlation is very high, of which the deviation from the experimental value is very small. (authors)

  8. Experimental research of inclined-micro-fin flat tube on single phase convection heat transfer

    International Nuclear Information System (INIS)

    Fan Guangming; Sun Zhongning; Wang Meng

    2011-01-01

    The experimental research of heat transfer and flow resistance characteristics of single phase water in four inclined-micro-fin flat tubes with different physical dimensions was conducted. At the same time,suitable criteria were selected to evaluate the efficiency of inclined-micro-fin flat tubes within the experimental scope and the optimal working region was determined. The results indicate that inclined-micro-fin flat tubes can greatly enhance the single-phase heat transfer in turbulent flow and the maximum heat transfer coefficient attains to 5.9 times of that in smooth tube. The quantities of heat transfer for inclined-micro-fin flat tubes are three times higher than that of smooth tube with the same of heat exchange area and pump power. (authors)

  9. Photoluminescence Polarization Anisotropy in a Single Heterostructured III-V Nanowire with Mixed Crystal Phases

    International Nuclear Information System (INIS)

    Moses, A. F.; Hoang, T. B.; Ahtapodov, L.; Dheeraj, D. L.; Fimland, B. O.; Weman, H.; Helvoort, A. T. J. van

    2011-01-01

    Low temperature (10 K) micro-photoluminescence (μ-PL) of single GaAs/AlGaAs core-shell nanowires with single GaAsSb inserts were measured. The PL emission from the zinc blende GaAsSb insert is strongly polarized along the nanowire axis while the PL emission from the wurtzite GaAs nanowire is perpendiculary polarized to the nanowire axis. The result indicates that the crystal phase, through the optical selection rules, has significant effect on the polarization of the PL from NWs besides the dielectric mismatch. The analysis of the PL results based on the electronic structure of these nanowires supports the correlation between the crystal phase and the PL emission.

  10. A Synchronization Method for Single-Phase Grid-Tied Inverters

    DEFF Research Database (Denmark)

    Hadjidemetriou, Lenos; Kyriakides, Elias; Yang, Yongheng

    2016-01-01

    The controllers of single-phase grid-tied inverters require improvements to enable distribution generation systems to meet the grid codes/standards with respect to power quality and the fault ride through capability. In that case, the response of the selected synchronization technique is crucial...... for the performance of the entire grid-tied inverter. In this paper, a new synchronization method with good dynamics and high accuracy under a highly distorted voltage is proposed. This method uses a Multi-Harmonic Decoupling Cell (MHDC), which thus can cancel out the oscillations on the synchronization signals due...... to the harmonic voltage distortion while maintaining the dynamic response of the synchronization. Therefore, the accurate and dynamic response of the proposed MHDC-PLL can be beneficial for the performance of the whole single-phase grid-tied inverter....

  11. Chromatographic lipophilicity determination using large volume injections of the solvents non-miscible with the mobile phase.

    Science.gov (United States)

    Sârbu, Costel; Naşcu-Briciu, Rodica Domnica; Casoni, Dorina; Kot-Wasik, Agata; Wasik, Andrzej; Namieśnik, Jacek

    2012-11-30

    A new perspective in the lipophilicity evaluation through RP-HPLC is permitted by analysis of the retention factor (k) obtained by injecting large volumes of test samples prepared in solvents immiscible with mobile phase. The experiment is carried out on representative groups of compounds with increased toxicity (mycotoxins and alkaloids) and amines with important biological activity (naturally occurring monoamine compounds and related drugs), which are covering a large interval of lipophilicity. The stock solution of each compound was prepared in hexane and the used mobile phases were mixtures of methanol or acetonitrile and water, in suited volume ratio. The injected volume was between 10 and 100 μL, while the used stationary phases were RP-18 and RP-8. On both reverse stationary phases the retention factors were linearly decreasing while the injection volume was increasing. In all cases, the linear models were highly statistically significant. On the basis of the obtained results new lipophilicity indices were purposed and discussed. The developed lipophilicity indices and the computationally expressed ones are correlated at a high level of statistical significance. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Removal of Direct Current Link Harmonic Ripple in Single Phase Voltage Source Inverter Systems Using Supercapacitors

    Science.gov (United States)

    2016-09-01

    Khaligh, “Optimization of sizing and battery cycle life in battery/ultracapacitor hybrid energy storage systems for electric vehicle applications...depth cycling operation in photovoltaic system ,” in 22nd International Conference “Mixed Design of Integrated Circuits and Systems ,” Toruń, Poland...CURRENT LINK HARMONIC RIPPLE IN SINGLE-PHASE VOLTAGE SOURCE INVERTER SYSTEMS USING SUPERCAPACITORS by Gabriel D. Hernandez September 2016

  13. Geometric relationships for homogenization in single-phase binary alloy systems

    Science.gov (United States)

    Unnam, J.; Tenney, D. R.; Stein, B. A.

    1978-01-01

    A semiempirical relationship is presented which describes the extent of interaction between constituents in single-phase binary alloy systems having planar, cylindrical, or spherical interfaces. This relationship makes possible a quick estimate of the extent of interaction without lengthy numerical calculations. It includes two parameters which are functions of mean concentration and interface geometry. Experimental data for the copper-nickel system are included to demonstrate the usefulness of this relationship.

  14. Single-phase flow and flow boiling of water in horizontal rectangular microchannels

    OpenAIRE

    Mirmanto

    2013-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University The current study is part of a long term experimental project devoted to investigating single-phase flow pressure drop and heat transfer, flow boiling pressure drop and heat transfer, flow boiling instability and flow visualization of de-ionized water flow in microchannels. The experimental facility was first designed and constructed by S. Gedupudi (2009) and in the present study; ...

  15. A facility for the experimental investigation of single substance two phase flow

    International Nuclear Information System (INIS)

    Maeder, P.F.; Dickinson, D.A.; Nikitopoulos, D.E.; DiPippo, R.

    1985-01-01

    The paper describes a research facility dedicated to single-substance two-phase flow. The working fluid is dichlorotetrafluoroethane (or refrigerant R-114), allowing both operation at manageable pressures, temperatures and flowrates, and application of results to practical situations through similarity. Operation is in the blowdown mode. The control and data acquisition systems are fully automated and computer controlled. A range of flow conditions from predominantly liquid flow to high velocity, high void fraction choked flow can be attained

  16. High-performance liquid chromatographic separations of stereoisomers of chiral basic agrochemicals with polysaccharide-based chiral columns and polar organic mobile phases.

    Science.gov (United States)

    Matarashvili, Iza; Shvangiradze, Iamze; Chankvetadze, Lali; Sidamonidze, Shota; Takaishvili, Nino; Farkas, Tivadar; Chankvetadze, Bezhan

    2015-12-01

    The separation of the stereoisomers of 23 chiral basic agrochemicals was studied on six different polysaccharide-based chiral columns in high-performance liquid chromatography with various polar organic mobile phases. Along with the successful separation of analyte stereoisomers, emphasis was placed on the effect of the chiral selector and mobile phase composition on the elution order of stereoisomers. The interesting phenomenon of reversal of enantiomer/stereoisomer elution order function of the polysaccharide backbone (cellulose or amylose), type of derivative (carbamate or benzoate), nature, and position of the substituent(s) in the phenylcarbamate moiety (methyl or chloro) and the nature of the mobile phase was observed. For several of the analytes containing two chiral centers all four stereoisomers were resolved with at least one chiral selector/mobile phase combination. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. On the development of a grid-enhanced single-phase convective heat transfer correlation

    International Nuclear Information System (INIS)

    Miller, D.J.; Cheung, F.B.; Bajorek, S.M.

    2011-01-01

    A new single-phase convective heat transfer augmentation correlation has been developed using single phase steam cooling experimental data obtained from the Penn State/NRC Rod Bundle Heat Transfer (RBHT) facility. Experimental data obtained from the RBHT single phase steam cooling tests have been evaluated and new findings identified. Previous rod bundle tests showed the importance of spacer grid on the local heat transfer, and that the augmentation in heat transfer downstream of a grid decays exponentially. The RBHT data also shows that the Reynolds number affects the rate at which this augmentation decays. The new correlation includes the strong dependence of heat transfer on both the Reynolds number and the grid blockage ratio. While the effects of both parameters were clearly evident in the RBHT experimental data, existing correlations do not account for the Reynolds number effect. The developed correlation incorporates Reynolds number in the decay curve of heat transfer. The newly developed correlation adequately accounts for the dependence of the heat transfer augmentation decay rate on the local flow Reynolds number. (author)

  18. Atomistic simulation of fcc—bcc phase transition in single crystal Al under uniform compression

    International Nuclear Information System (INIS)

    Li Li; Liang Jiu-Qing; Shao Jian-Li; Duan Su-Qing; Li Yan-Fang

    2012-01-01

    By molecular dynamics simulations employing an embedded atom model potential, we investigate the fcc-to-bcc phase transition in single crystal Al, caused by uniform compression. Results show that the fcc structure is unstable when the pressure is over 250 GPa, in reasonable agreement with the calculated value through the density functional theory. The morphology evolution of the structural transition and the corresponding transition mechanism are analysed in detail. The bcc (011) planes are transited from the fcc (111-bar) plane and the (11-bar1) plane. We suggest that the transition mechanism consists mainly of compression, shear, slid and rotation of the lattice. In addition, our radial distribution function analysis explicitly indicates the phase transition of Al from fcc phase to bcc structure. (condensed matter: structural, mechanical, and thermal properties)

  19. Selectivity of single, mixed, and modified pseudostationary phases in electrokinetic chromatography.

    Science.gov (United States)

    Fuguet, Elisabet; Ràfols, Clara; Bosch, Elisabeth; Abraham, Michael H; Rosés, Martí

    2006-05-01

    The selectivity of a compilation of single, mixed, and modified EKC pseudostationary phases, described in the literature and characterized through the solvation parameter model, is analyzed. Not only have micellar systems of different nature been included but also microemulsions, polymeric, and liposomial phases. In order to compare the systems, a principal component analysis of the coefficients of the solvation equation is performed. From this analysis, direct information of the system properties, differences in selectivity, as well as evidence of lack of accuracy in some system characterizations are obtained. These results become a very useful tool to perform separations with mixtures of surfactants, since it is possible to know which mixtures will provide a greater selectivity variation by changing only the composition of the pseudostationary phases. Furthermore, the variation of the selectivity of some mixtures, as well as the effect of the addition of organic solvents on selectivity, is also discussed.

  20. Magnetic phases in Pt/Co/Pt films induced by single and multiple femtosecond laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Kisielewski, J., E-mail: jankis@uwb.edu.pl; Kurant, Z.; Sveklo, I.; Tekielak, M.; Maziewski, A. [Faculty of Physics, University of Białystok, Ciołkowskiego 1L, 15-245 Białystok (Poland); Wawro, A. [Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw (Poland)

    2016-05-21

    Ultrathin Pt/Co/Pt trilayers with initial in-plane magnetization were irradiated with femtosecond laser pulses. In this way, an irreversible structural modification was introduced, which resulted in the creation of numerous pulse fluence-dependent magnetic phases. This was particularly true with the out-of-plane magnetization state, which exhibited a submicrometer domain structure. This effect was studied in a broad range of pulse fluences up to the point of ablation of the metallic films. In addition to this single-pulse experiment, multiple exposure spots were also investigated, which exhibited an extended area of out-of-plane magnetization phases and a decreased damage threshold. Using a double exposure with partially overlapped spots, a two-dimensional diagram of the magnetic phases as a function of the two energy densities was built, which showed a strong inequality between the first and second incoming pulses.

  1. Magnetic phases in Pt/Co/Pt films induced by single and multiple femtosecond laser pulses

    International Nuclear Information System (INIS)

    Kisielewski, J.; Kurant, Z.; Sveklo, I.; Tekielak, M.; Maziewski, A.; Wawro, A.

    2016-01-01

    Ultrathin Pt/Co/Pt trilayers with initial in-plane magnetization were irradiated with femtosecond laser pulses. In this way, an irreversible structural modification was introduced, which resulted in the creation of numerous pulse fluence-dependent magnetic phases. This was particularly true with the out-of-plane magnetization state, which exhibited a submicrometer domain structure. This effect was studied in a broad range of pulse fluences up to the point of ablation of the metallic films. In addition to this single-pulse experiment, multiple exposure spots were also investigated, which exhibited an extended area of out-of-plane magnetization phases and a decreased damage threshold. Using a double exposure with partially overlapped spots, a two-dimensional diagram of the magnetic phases as a function of the two energy densities was built, which showed a strong inequality between the first and second incoming pulses.

  2. Creating diversified response profiles from a single quenchometric sensor element by using phase-resolved luminescence.

    Science.gov (United States)

    Tehan, Elizabeth C; Bukowski, Rachel M; Chodavarapu, Vamsy P; Titus, Albert H; Cartwright, Alexander N; Bright, Frank V

    2015-01-05

    We report a new strategy for generating a continuum of response profiles from a single luminescence-based sensor element by using phase-resolved detection. This strategy yields reliable responses that depend in a predictable manner on changes in the luminescent reporter lifetime in the presence of the target analyte, the excitation modulation frequency, and the detector (lock-in amplifier) phase angle. In the traditional steady-state mode, the sensor that we evaluate exhibits a linear, positive going response to changes in the target analyte concentration. Under phase-resolved conditions the analyte-dependent response profiles: (i) can become highly non-linear; (ii) yield negative going responses; (iii) can be biphasic; and (iv) can exhibit super sensitivity (e.g., sensitivities up to 300 fold greater in comparison to steady-state conditions).

  3. Optical study of phase transitions in single-crystalline RuP

    Science.gov (United States)

    Chen, R. Y.; Shi, Y. G.; Zheng, P.; Wang, L.; Dong, T.; Wang, N. L.

    2015-03-01

    RuP single crystals of MnP-type orthorhombic structure were synthesized by the Sn flux method. Temperature-dependent x-ray diffraction measurements reveal that the compound experiences two structural phase transitions, which are further confirmed by enormous anomalies shown in temperature-dependent resistivity and magnetic susceptibility. Particularly, the resistivity drops monotonically upon temperature cooling below the second transition, indicating that the material shows metallic behavior, in sharp contrast with the insulating ground state of polycrystalline samples. Optical conductivity measurements were also performed in order to unravel the mechanism of these two transitions. The measurement revealed a sudden reconstruction of band structure over a broad energy scale and a significant removal of conducting carriers below the first phase transition, while a charge-density-wave-like energy gap opens below the second phase transition.

  4. Influence of modulation method on using LC-traps with single-phase voltage source converters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Min, Huang; Bai, Haofeng

    2015-01-01

    The switching-frequency LC-trap filter has recently been employed with high-order passive filters for Voltage Source Inverters (VSIs). This paper investigates the influence of modulation method on using the LC-traps with single-phase VSIs. Two-level (bipolar) and three-level (unipolar) modulations...... that include phase distortion and alternative phase opposition distortion methods are analyzed. Harmonic filtering performances of four LC-trap-based filters with different locations of LC-traps are compared. It is shown that the use of parallel-LC-traps in series with filter inductors, either grid...... or converter side, has a worse harmonic filtering performance than using series-LC-trap in the shunt branch. Simulations and experimental results are presented for verifications....

  5. Orientational Phase Transition Around 274 K in C60 Single Crystal

    Institute of Scientific and Technical Information of China (English)

    徐亚伯; 何丕模; 杨宏顺; 郑萍; 余朝文; 陈兆甲; 张宣嘉; 李文铸

    1994-01-01

    The electrical conductivity of a C60 single crystal around 274 K and the specific heat of C60 crystals from 150 to 340 K have been measured.The delta-like specific heat peak at about 251 K related to the first-order phase transition has been reported.The activation energy change around 274 K and the lambda-like specific heat peak beginning at 270 K and ending at 310 K show that there is an orientational phase transition in fcc C60 crystals above 251 K.By taking the symmetry into consideration and further analyzing lambda-like specific heat peak and the activation energy change around 274 K,the conclusion has been reached that this new phase transition is an orientational structure transition from the merohedral twinning fcc to the orientationally disordered fcc.The temperature of free rotation of C60 molecules is about 281 K.

  6. Scintigraphic demonstration of single- or two-phase gastric emptying in diabetics

    International Nuclear Information System (INIS)

    Eikman, E.A.; Leichter, S.; Waldholtz, B.; Tenorio, L.; Brady, P.

    1989-01-01

    This paper discusses how a modified scintigraphic test of gastric emptying revealed two types of abnormal gastric emptying in diabetic patients. After ingestion of 100 mL of cooked egg whites labeled with 0.5 mCi of Tc-99m sulfur colloid, the geometric mean stomach radioactivity was recorded serially for 90 minutes. Linear regression computed for the log of radioactivity versus time facilitated recognition of changes in gastric emptying. In 16 of 25 consecutive diabetic patients with postprandial symptoms, initial slow emptying (half-life,>100 minutes) was observed. Single-phase emptying was shown in seven of these patients. In nine patients, the slow-emptying phase lasted up to 50 minutes, followed by a distinct second phase of normal or rapid emptying (half-life, <40 minutes). The existence of different gastric emptying implies differing mechanisms of delay and may be important in treatment

  7. A Nonadaptive Window-Based PLL for Single-Phase Applications

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2018-01-01

    The rectangular window filter, typically known as the moving average filter (MAF), is a quasi-ideal low-pass filter that has found wide application in designing advanced single-phase phase-locked loops (PLLs). Most often, the MAF is employed as an in-loop filter within the control loop of the sin......The rectangular window filter, typically known as the moving average filter (MAF), is a quasi-ideal low-pass filter that has found wide application in designing advanced single-phase phase-locked loops (PLLs). Most often, the MAF is employed as an in-loop filter within the control loop...... response is avoided. Nevertheless, the PLL implementation complexity considerably increases as MAFs are frequency-adaptive and, therefore, they require an additional frequency detector for estimating the grid frequency. To reduce the implementation complexity while maintaining a good performance, using...... a nonadaptive MAF-based QSG with some error compensators is suggested in this letter. The effectiveness of the resultant PLL, which is briefly called the nonadaptive MAF-based PLL, is verified using experimental results....

  8. Single-sphere multiple-detector neutron spectrometer. Final report on Phase 1

    International Nuclear Information System (INIS)

    Sinclair, F.; Stern, I.; Hahn, R.W.; Entine, G.

    1987-07-01

    To address the problem of accurate, timely estimates of the neutron spectral flux, researchers are developing a monitoring instrument based on a single moderating sphere with a large number of independent sensors. Such a single-sphere spectrometer would allow easy measurement of quality factors. This is made possible by the recent development of a novel digital sensor which detects radiation induced errors in a dynamic random-access memory. During Phase I of the SBIR program, researchers constructed a first prototype of the single-sphere spectrometer, measured its response in a neutron flux from an isotopic Am-Be source in several geometries, and compared these with the results of Monte Carlo simulations of neutron transport. The preliminary results show that the approach is feasible and relatively straightforward

  9. High resolution transmission electron microscopy studies of {sigma} phase in Ni-based single crystal superalloys

    Energy Technology Data Exchange (ETDEWEB)

    Sun Fei [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Zhang Jianxin, E-mail: jianxin@sdu.edu.cn [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Liu Pan [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China); Feng Qiang [National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Han Xiaodong; Mao Shengcheng [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China)

    2012-09-25

    Graphical abstract: (a) TEM micrograph of {sigma} phase; (b) HRTEM image of {sigma}/{gamma} interface corresponding to the area of the white frame in (a); (c) an enlarged image of area from the white frame in (b). The combination of {sigma}/{gamma} interface appears very well, and a two-atomic-layer step is shown on the {sigma}/{gamma} interface. In addition, {sigma} phase has the orientation relationship of [0 0 1]{sub {gamma}}//[1 1 2{sup Macron }]{sub {sigma}}, (2{sup Macron} 2 0){sub {gamma}}//(1{sup Macron} 1 0){sub {sigma}}, (2{sup Macron }2{sup Macron} 0){sub {gamma}}//(1 1 1){sub {sigma}}; [0 1 1]{sub {gamma}}//[1 1 0]{sub {sigma}}, (1 1{sup Macron} 1){sub {gamma}}//(0 0 1{sup Macron }){sub {sigma}} with the {gamma} phase. Highlights: Black-Right-Pointing-Pointer Elemental characteristic of {sigma} phase is studied by HAADF techniques and EDS analysis. Black-Right-Pointing-Pointer Interfacial characteristics of {sigma}/{gamma} interface are revealed by HRTEM. Black-Right-Pointing-Pointer An atomic structural {sigma}/{gamma} interface with a two-atomic-layer step has been proposed. - Abstract: By means of high resolution transmission electron microscopy (HRTEM) and high-angle annular dark-field image technique (HAADF), morphological of plate-shaped {sigma} phase and interfacial characteristics between plate-shaped {sigma} phase and {gamma} phase in Ni-based single crystal superalloys have been studied. On the basis of HRTEM observations, an atomic structural interface between {sigma} phase and {gamma} phase with a step has been proposed. {sigma} Phase has the relationship of [0 0 1]{sub {gamma}}//[1 1 2{sup Macron }]{sub {sigma}}, (2{sup Macron} 2 0){sub {gamma}}//(1{sup Macron} 1 0){sub {sigma},} (2{sup Macron }2{sup Macron} 0){sub {gamma}}//(1 1 1){sub {sigma}}; [0 1 1]{sub {gamma}}//[1 1 0]{sub {sigma}}, (1 1{sup Macron} 1){sub {gamma}}//(0 0 1{sup Macron }){sub {sigma}} with the {gamma} phase. The compositional characteristics of the {sigma} phase which

  10. The effects of ruthenium on the phase stability of fourth generation Ni-base single crystal superalloys

    International Nuclear Information System (INIS)

    Sato, Atsushi; Harada, Hiroshi; Yokokawa, Tadaharu; Murakumo, Takao; Koizumi, Yutaka; Kobayashi, Toshiharu; Imai, Hachiro

    2006-01-01

    The formation of topologically close-packed (TCP) phases in nickel-base single crystal superalloys causes considerable degradation of the mechanical properties. It has recently been found that platinum-group metals can be effective in controlling the precipitation of such phases, and this extent of precipitation control requires further investigation. This study compares Ru-containing and non-Ru-containing single crystal superalloys. Scanning electron microscopy microstructural observations showed that the rate of TCP phase precipitations decreased through Ru addition. Transmission electron microscopy microstructural observations showed that the P phase, one of the TCP phases, was eliminated through the addition of Ru. The occurrence of this phenomenon will be discussed

  11. Characterization of Single Phase and Two Phase Heat and Momentum Transport in a Spiraling Radial Inow Microchannel Heat Sink

    Science.gov (United States)

    Ruiz, Maritza

    Thermal management of systems under high heat fluxes on the order of hundreds of W/cm2 is important for the safety, performance and lifetime of devices, with innovative cooling technologies leading to improved performance of electronics or concentrating solar photovoltaics. A novel, spiraling radial inflow microchannel heat sink for high flux cooling applications, using a single phase or vaporizing coolant, has demonstrated enhanced heat transfer capabilities. The design of the heat sink provides an inward swirl flow between parallel, coaxial disks that form a microchannel of 1 cm radius and 300 micron channel height with a single inlet and a single outlet. The channel is heated on one side through a conducting copper surface, and is essentially adiabatic on the opposite side to simulate a heat sink scenario for electronics or concentrated photovoltaics cooling. Experimental results on the heat transfer and pressure drop characteristics in the heat sink, using single phase water as a working fluid, revealed heat transfer enhancements due to flow acceleration and induced secondary flows when compared to unidirectional laminar fully developed flow between parallel plates. Additionally, thermal gradients on the surface are small relative to the bulk fluid temperature gain, a beneficial feature for high heat flux cooling applications. Heat flux levels of 113 W/cm2 at a surface temperature of 77 deg C were reached with a ratio of pumping power to heat rate of 0.03%. Analytical models on single phase flow are used to explore the parametric trends of the flow rate and passage geometry on the streamlines and pressure drop through the device. Flow boiling heat transfer and pressure drop characteristics were obtained for this heat sink using water at near atmospheric pressure as the working fluid for inlet subcooling levels ranging from 20 to 80 deg C and mean mass flux levels ranging from 184-716 kg/m. 2s. Flow enhancements similar to singlephase flow were expected, as well

  12. Task Phase Recognition for Highly Mobile Workers in Large Building Complexes

    DEFF Research Database (Denmark)

    Stisen, Allan; Mathisen, Andreas; Krogh, Søren

    2016-01-01

    requirements on the accuracy of the indoor positioning, and thus come with low deployment and maintenance effort in real-world settings. We evaluated the proposed methods in a large hospital complex, where the highly mobile workers were recruited among the non-clinical workforce. The evaluation is based......-scale indoor work environments, namely from a WiFi infrastructure providing coarse grained indoor positioning, from inertial sensors in the workers’ mobile phones, and from a task management system yielding information about the scheduled tasks’ start and end locations. The methods presented have low...... on manually labelled real-world data collected over 4 days of regular work life of the mobile workforce. The collected data yields 83 tasks in total involving 8 different orderlies from a major university hospital with a building area of 160, 000 m2. The results show that the proposed methods can distinguish...

  13. Active Vibration Isolation System for Mobile Launch Platform Ground Support Equipment, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — During our Phase I STTR effort, Balcones Technologies, LLC and The University of Texas Center for Electromechanics (CEM) successfully achieved all Phase I objectives...

  14. Effect of duration of the pause single-phase auto-reclosing on electro-power transmission capacitance

    Directory of Open Access Journals (Sweden)

    Krasil'nikova Tatyana

    2017-01-01

    Full Text Available This paper discusses the problem associated with accidents in the aerial line (AL ultra-high voltage (UHV due to its big length. In lines with a voltage of 500-1150 kV the overwhelming proportion of trips (98% is caused by single-phase short circuit (SPSC. A substantial portion (70% single-phase short circuits is erratic arc accidents which can be successfully eliminated in a high-speed auto-reclosing (HSAR or single-phase auto-reclosing (SPAR. Success single-phase auto-reclosing (SPAR at liquidation by single-phase short circuit (SPSC, on the one hand, is determined by the characteristics of the secondary arc current, and on the other hand the effectiveness of ways to reduce secondary arc current and recovery voltage development. The minimum dead time, at a HSAR it is usually taken as 0.5 s., at single-phase autoreclosing (SPAR it depends on the current value of the arc support is in the range of 0.5-3.0 s. The article shows high efficiency of use single-phase auto reclosing (SPAR at liquidation SPSC in a single-chain AL voltage of 500 kV, the dependence of the bandwidth of transmission in maintaining the dynamic stability from the length of the pause SPAR.

  15. Rich magnetoelectric phase diagrams of multiferroic single-crystal α -NaFeO2

    Science.gov (United States)

    Terada, Noriki; Ikedo, Yuta; Sato, Hirohiko; Khalyavin, Dmitry D.; Manuel, Pascal; Miyake, Atsushi; Matsuo, Akira; Tokunaga, Masashi; Kindo, Koichi

    2017-07-01

    The magnetic and dielectric properties of the multiferroic triangular lattice magnet compound α -NaFeO2 were studied by magnetization, specific heat, dielectric permittivity, and pyroelectric current measurements and by neutron diffraction experiments using single crystals grown by a hydrothermal synthesis method. This work produced magnetic field (in the monoclinic a b -plane, Ba b, and along the c*-axis, Bc) versus temperature magnetic phase diagrams, including five and six magnetically ordered phases in Ba b and along Bc, respectively. In zero magnetic field, two spin-density-wave orderings with different k vectors—(0 ,q ,1/2 ) in phase I and (qa,qb,qc ) in phase II—appeared at T =9.5 and 8.25 K, respectively. Below T =5 K, a commensurate order with k =(0.5 ,0 ,0.5 ) was stabilized as the ground state in phase III. Both Ba b≥3 T and Bc≥5 T were found to induce ferroelectric phases at the lowest temperature (2 K), with an electric polarization that was not confined to any highly symmetric directions in phases IVa b (3.3 ≤Ba b≤8.5 T), Va b (8.5 ≤Ba b≤13.6 T), IVc (5.0 ≤Bc≤8.5 T), and Vc (8.5 ≤Bc≤13.5 T). In phase VIc, within a narrow temperature region in Bc, the polarization was confined to the a b plane. For each of the ferroelectric phases, the k vector was (qa,qb,qc ), and noncollinear structures were identified, including a general spiral in IVa b an a b cycloid in IVc and Vc, and a proper screw in VIc, along with a triclinic 11' magnetic point group allowing polarization in the general direction. Comparing the polarization direction to the magnetic structures in the ferroelectric phases, we conclude that the extended inverse Dzyaloshinskii-Moriya mechanism expressed by the orthogonal components p1∝ri j×(Si×Sj) and p2∝Si×Sj can explain the polarization directions. Based on calculations incorporating exchange interactions up to fourth-nearest-neighbor (NN) couplings, we infer that competition among antiferromagnetic second NN

  16. A control strategy for induction motors fed from single phase supply

    DEFF Research Database (Denmark)

    Søndergård, Lars Møller

    1993-01-01

    It is often required that a three-phased asynchronous motor can run at variable speed, which makes it necessary to use a three-phase inverter driven from a DC-source. Today, most inverters are driven from the network using a simple diode bridge and an electrolytic capacitor. The problem with the ......It is often required that a three-phased asynchronous motor can run at variable speed, which makes it necessary to use a three-phase inverter driven from a DC-source. Today, most inverters are driven from the network using a simple diode bridge and an electrolytic capacitor. The problem...... with the simple diode bridge and the electrolytic capacitor is that current is only drawn for short periods, which gives rise to harmonic currents in the network. For small drive systems (motor+inverter), i.e. less than 1.5 kW, a single phase network outlet is often used. The author describes a method whereby...

  17. New three-phase ac-ac converter incorporating three-phase boost integrated ZVT bridge and single-phase HF link

    International Nuclear Information System (INIS)

    Abdelhamid, Tamer H.; Sabzali, Ahmad J.

    2008-01-01

    This paper presents a new zero voltage transition (ZVT), power factor corrected three phase ac-ac converter with single phase high frequency (HF) link. It is a two stage converter; the first stage is a boost integrated bridge converter (combination of a 3 ph boost converter and a bridge converter) operated at fixed frequency and that operates in two modes at ZVT for all switches and establishes a 1 ph square wave HF link. The second stage is a bi-directional pulse width modulation (PWM) 3 ph bridge that converts the 1 ph HF link to a 3 ph voltage using a novel switching strategy. The converter modes of operation and key equations are outlined. Simulation of the overall system is conducted using Simulink. The switching strategy and its corresponding control circuit are clearly described. Experimental verification of the simulation is conducted for a prototype of 100 V, 500 W at 10 kHz link frequency

  18. Artificial neural network modelling of retention of pesticides in various octadecylsiloxane-bonded reversed-phase columns and water-acetonitrile mobile phase

    International Nuclear Information System (INIS)

    D'Archivio, Angelo Antonio; Maggi, Maria Anna; Mazzeo, Pietro; Ruggieri, Fabrizio

    2009-01-01

    Previously, retention of 26 pesticides in the reversed-phase column Gemini (Phenomenex) and water-acetonitrile mobile phase was modelled using a feed-forward artificial neural network (ANN) learned by error back-propagation, accounting for both the effect of solute structure and mobile phase composition. To this end, log K ow of solutes and four quantum chemical molecular descriptors (the dipole moment, the mean polarizability, the anisotropy of the polarizability and an hydrogen-bonding descriptor based on the atomic charges located on the acid and basic functional groups) and acetonitrile % (v/v) in the eluent (%ACN) were used as ANN inputs. The above ANN-based approach is here tested on further five similar octadecylsiloxane-bonded columns in water-acetonitrile mobile phase within the %ACN range 30-70%. A quite good predictive performance evaluated on three external solutes in the whole %ACN range is observed, prediction errors being lower than ±0.1 log k units or slightly higher although still within ±0.15 log k units. On the other hand, multilinear regression used in place of ANN provides a more diffuse and non-uniform residual distribution for all the investigated columns. ANN multiple-column retention prediction is attempted by adding to the above variables a column descriptor defined as the average retention of calibration solutes extrapolated to 100% water. This more general model is built using 16 solutes and five 5-μm columns in calibration, while its predictive performance is tested on the remaining 10 compounds. Under these conditions, prediction errors are generally within ±0.2 log k units regardless of the kind of column. The possibility of cross-column prediction is evaluated by column leave-one-out cross-validation within the five 5-μm stationary phases and on a 4-μm external column. This analysis reveals that accuracy of retention prediction for unknown solutes in unknown columns is acceptable provided that the external column is not very

  19. Artificial neural network modelling of retention of pesticides in various octadecylsiloxane-bonded reversed-phase columns and water-acetonitrile mobile phase

    Energy Technology Data Exchange (ETDEWEB)

    D' Archivio, Angelo Antonio, E-mail: angeloantonio.darchivio@univaq.it [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy); Maggi, Maria Anna; Mazzeo, Pietro; Ruggieri, Fabrizio [Dipartimento di Chimica, Ingegneria Chimica e Materiali, Universita degli Studi di L' Aquila, Via Vetoio, 67010 Coppito, L' Aquila (Italy)

    2009-07-30

    Previously, retention of 26 pesticides in the reversed-phase column Gemini (Phenomenex) and water-acetonitrile mobile phase was modelled using a feed-forward artificial neural network (ANN) learned by error back-propagation, accounting for both the effect of solute structure and mobile phase composition. To this end, log K{sub ow} of solutes and four quantum chemical molecular descriptors (the dipole moment, the mean polarizability, the anisotropy of the polarizability and an hydrogen-bonding descriptor based on the atomic charges located on the acid and basic functional groups) and acetonitrile % (v/v) in the eluent (%ACN) were used as ANN inputs. The above ANN-based approach is here tested on further five similar octadecylsiloxane-bonded columns in water-acetonitrile mobile phase within the %ACN range 30-70%. A quite good predictive performance evaluated on three external solutes in the whole %ACN range is observed, prediction errors being lower than {+-}0.1 log k units or slightly higher although still within {+-}0.15 log k units. On the other hand, multilinear regression used in place of ANN provides a more diffuse and non-uniform residual distribution for all the investigated columns. ANN multiple-column retention prediction is attempted by adding to the above variables a column descriptor defined as the average retention of calibration solutes extrapolated to 100% water. This more general model is built using 16 solutes and five 5-{mu}m columns in calibration, while its predictive performance is tested on the remaining 10 compounds. Under these conditions, prediction errors are generally within {+-}0.2 log k units regardless of the kind of column. The possibility of cross-column prediction is evaluated by column leave-one-out cross-validation within the five 5-{mu}m stationary phases and on a 4-{mu}m external column. This analysis reveals that accuracy of retention prediction for unknown solutes in unknown columns is acceptable provided that the external

  20. Simulation of single grid-based phase-contrast x-ray imaging (g-PCXI)

    Energy Technology Data Exchange (ETDEWEB)

    Lim, H.W.; Lee, H.W. [Department of Radiation Convergence Engineering, iTOMO Group, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 26493 (Korea, Republic of); Cho, H.S., E-mail: hscho1@yonsei.ac.kr [Department of Radiation Convergence Engineering, iTOMO Group, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 26493 (Korea, Republic of); Je, U.K.; Park, C.K.; Kim, K.S.; Kim, G.A.; Park, S.Y.; Lee, D.Y.; Park, Y.O.; Woo, T.H. [Department of Radiation Convergence Engineering, iTOMO Group, Yonsei University, 1 Yonseidae-gil, Wonju, Gangwon-do 26493 (Korea, Republic of); Lee, S.H.; Chung, W.H.; Kim, J.W.; Kim, J.G. [R& D Center, JPI Healthcare Co., Ltd., Ansan 425-833 (Korea, Republic of)

    2017-04-01

    Single grid-based phase-contrast x-ray imaging (g-PCXI) technique, which was recently proposed by Wen et al. to retrieve absorption, scattering, and phase-gradient images from the raw image of the examined object, seems a practical method for phase-contrast imaging with great simplicity and minimal requirements on the setup alignment. In this work, we developed a useful simulation platform for g-PCXI and performed a simulation to demonstrate its viability. We also established a table-top setup for g-PCXI which consists of a focused-linear grid (200-lines/in strip density), an x-ray tube (100-μm focal spot size), and a flat-panel detector (48-μm pixel size) and performed a preliminary experiment with some samples to show the performance of the simulation platform. We successfully obtained phase-contrast x-ray images of much enhanced contrast from both the simulation and experiment and the simulated contract seemed similar to the experimental contrast, which shows the performance of the developed simulation platform. We expect that the simulation platform will be useful for designing an optimal g-PCXI system. - Highlights: • It is proposed for the single grid-based phase-contrast x-ray imaging (g-PCXI) technique. • We implemented for a numerical simulation code. • The preliminary experiment with several samples to compare is performed. • It is expected to be useful to design an optimal g-PCXI system.

  1. Mixture-mixture design for the fingerprint optimization of chromatographic mobile phases and extraction solutions for Camellia sinensis.

    Science.gov (United States)

    Borges, Cleber N; Bruns, Roy E; Almeida, Aline A; Scarminio, Ieda S

    2007-07-09

    A composite simplex centroid-simplex centroid mixture design is proposed for simultaneously optimizing two mixture systems. The complementary model is formed by multiplying special cubic models for the two systems. The design was applied to the simultaneous optimization of both mobile phase chromatographic mixtures and extraction mixtures for the Camellia sinensis Chinese tea plant. The extraction mixtures investigated contained varying proportions of ethyl acetate, ethanol and dichloromethane while the mobile phase was made up of varying proportions of methanol, acetonitrile and a methanol-acetonitrile-water (MAW) 15%:15%:70% mixture. The experiments were block randomized corresponding to a split-plot error structure to minimize laboratory work and reduce environmental impact. Coefficients of an initial saturated model were obtained using Scheffe-type equations. A cumulative probability graph was used to determine an approximate reduced model. The split-plot error structure was then introduced into the reduced model by applying generalized least square equations with variance components calculated using the restricted maximum likelihood approach. A model was developed to calculate the number of peaks observed with the chromatographic detector at 210 nm. A 20-term model contained essentially all the statistical information of the initial model and had a root mean square calibration error of 1.38. The model was used to predict the number of peaks eluted in chromatograms obtained from extraction solutions that correspond to axial points of the simplex centroid design. The significant model coefficients are interpreted in terms of interacting linear, quadratic and cubic effects of the mobile phase and extraction solution components.

  2. Chiral separation of aryloxyphenoxy-propionate herbicides in a permethyl-β-cyclodextrin based column. Influence of temperature and mobile phase composition on enantioselectivity.

    Science.gov (United States)

    Lubomirsky, Ester; Padró, Juan M; Di Loreto, Héctor; Castells, Cecilia B

    2017-08-01

    We used a permethyl-β-cyclodextrin chiral stationary phase under reversed-phase conditions for the chiral separation of four aryloxyphenoxy-propionate herbicides (fenoxaprop-p-ethyl, quizalofop-p-ethyl and tefuryl, and haloxyfop-p-methyl) with mixtures of methanol, ethanol, 2-propanol, n-propanol, tert-butanol, or acetonitrile and water as mobile phases and investigated the influence of mobile phase composition and column temperature (from 0 to 50°C) on the separation. The retention factors (k) and selectivity factors (α) of all the herbicides investigated decreased with increasing temperature. The lnα versus 1/T and lnk versus 1/T plots for the enantiomers of the chiral pesticides were linear within the range of 0-50°C with all alcohol/water mixtures constituting the mobile phase, but the lnk versus 1/T plots were nonlinear for all the enantiomers chromatographed in acetonitrile/water mixtures. The thermodynamic parameters based on linear van't Hoff plots were calculated. The influence of temperature and mobile phase composition on the enantioseparation of the solutes has rarely been considered simultaneously. The temperature and the solvents used in the mobile phase, however, were found to have a profound effect on the enantioseparation of these herbicides. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Replica Node Detection Using Enhanced Single Hop Detection with Clonal Selection Algorithm in Mobile Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    L. S. Sindhuja

    2016-01-01

    Full Text Available Security of Mobile Wireless Sensor Networks is a vital challenge as the sensor nodes are deployed in unattended environment and they are prone to various attacks. One among them is the node replication attack. In this, the physically insecure nodes are acquired by the adversary to clone them by having the same identity of the captured node, and the adversary deploys an unpredictable number of replicas throughout the network. Hence replica node detection is an important challenge in Mobile Wireless Sensor Networks. Various replica node detection techniques have been proposed to detect these replica nodes. These methods incur control overheads and the detection accuracy is low when the replica is selected as a witness node. This paper proposes to solve these issues by enhancing the Single Hop Detection (SHD method using the Clonal Selection algorithm to detect the clones by selecting the appropriate witness nodes. The advantages of the proposed method include (i increase in the detection ratio, (ii decrease in the control overhead, and (iii increase in throughput. The performance of the proposed work is measured using detection ratio, false detection ratio, packet delivery ratio, average delay, control overheads, and throughput. The implementation is done using ns-2 to exhibit the actuality of the proposed work.

  4. Ultrahigh Carrier Mobility Achieved in Photoresponsive Hybrid Perovskite Films via Coupling with Single-Walled Carbon Nanotubes

    KAUST Repository

    Li, Feng; Wang, Hong; Kufer, Dominik; Liang, Liangliang; Yu, Weili; Alarousu, Erkki; Ma, Chun; Li, Yangyang; Liu, Zhixiong; Liu, Changxu; Wei, Nini; Wang, Fei; Chen, Lang; Mohammed, Omar F.; Fratalocchi, Andrea; Liu, Xiaogang; Konstantatos, Gerasimos; Wu, Tao

    2017-01-01

    Organolead trihalide perovskites have drawn substantial interest for photovoltaic and optoelectronic applications due to their remarkable physical properties and low processing cost. However, perovskite thin films suffer from low carrier mobility as a result of their structural imperfections such as grain boundaries and pinholes, limiting their device performance and application potential. Here we demonstrate a simple and straightforward synthetic strategy based on coupling perovskite films with embedded single-walled carbon nanotubes. We are able to significantly enhance the hole and electron mobilities of the perovskite film to record-high values of 595.3 and 108.7 cm(2) V(-1) s(-1) , respectively. Such a synergistic effect can be harnessed to construct ambipolar phototransistors with an ultrahigh detectivity of 3.7 × 10(14) Jones and a responsivity of 1 × 10(4) A W(-1) , on a par with the best devices available to date. The perovskite/carbon nanotube hybrids should provide a platform that is highly desirable for fields as diverse as optoelectronics, solar energy conversion, and molecular sensing.

  5. Ultrahigh Carrier Mobility Achieved in Photoresponsive Hybrid Perovskite Films via Coupling with Single-Walled Carbon Nanotubes

    KAUST Repository

    Li, Feng

    2017-02-22

    Organolead trihalide perovskites have drawn substantial interest for photovoltaic and optoelectronic applications due to their remarkable physical properties and low processing cost. However, perovskite thin films suffer from low carrier mobility as a result of their structural imperfections such as grain boundaries and pinholes, limiting their device performance and application potential. Here we demonstrate a simple and straightforward synthetic strategy based on coupling perovskite films with embedded single-walled carbon nanotubes. We are able to significantly enhance the hole and electron mobilities of the perovskite film to record-high values of 595.3 and 108.7 cm(2) V(-1) s(-1) , respectively. Such a synergistic effect can be harnessed to construct ambipolar phototransistors with an ultrahigh detectivity of 3.7 × 10(14) Jones and a responsivity of 1 × 10(4) A W(-1) , on a par with the best devices available to date. The perovskite/carbon nanotube hybrids should provide a platform that is highly desirable for fields as diverse as optoelectronics, solar energy conversion, and molecular sensing.

  6. Direct phase selection of initial phases from single-wavelength anomalous dispersion (SAD) for the improvement of electron density and ab initio structure determination

    International Nuclear Information System (INIS)

    Chen, Chung-De; Huang, Yen-Chieh; Chiang, Hsin-Lin; Hsieh, Yin-Cheng; Guan, Hong-Hsiang; Chuankhayan, Phimonphan; Chen, Chun-Jung

    2014-01-01

    A novel direct phase-selection method to select optimized phases from the ambiguous phases of a subset of reflections to replace the corresponding initial SAD phases has been developed. With the improved phases, the completeness of built residues of protein molecules is enhanced for efficient structure determination. Optimization of the initial phasing has been a decisive factor in the success of the subsequent electron-density modification, model building and structure determination of biological macromolecules using the single-wavelength anomalous dispersion (SAD) method. Two possible phase solutions (ϕ 1 and ϕ 2 ) generated from two symmetric phase triangles in the Harker construction for the SAD method cause the well known phase ambiguity. A novel direct phase-selection method utilizing the θ DS list as a criterion to select optimized phases ϕ am from ϕ 1 or ϕ 2 of a subset of reflections with a high percentage of correct phases to replace the corresponding initial SAD phases ϕ SAD has been developed. Based on this work, reflections with an angle θ DS in the range 35–145° are selected for an optimized improvement, where θ DS is the angle between the initial phase ϕ SAD and a preliminary density-modification (DM) phase ϕ DM NHL . The results show that utilizing the additional direct phase-selection step prior to simple solvent flattening without phase combination using existing DM programs, such as RESOLVE or DM from CCP4, significantly improves the final phases in terms of increased correlation coefficients of electron-density maps and diminished mean phase errors. With the improved phases and density maps from the direct phase-selection method, the completeness of residues of protein molecules built with main chains and side chains is enhanced for efficient structure determination

  7. A Switchable 3D-Coverage Phased Array Antenna Package for 5G Mobile Terminals

    DEFF Research Database (Denmark)

    Ojaroudiparchin, Naser; Shen, Ming; Zhang, Shuai

    2016-01-01

    This manuscript proposes a new design of a millimeter-wave (mm-Wave) array antenna package with beam steering characteristic for the fifth generation (5G) mobile applications. In order to achieve a broad 3D scanning coverage of the space with high-gain beams, three identical sub arrays of patch a...... and efficiency, which is suitable for 5G mobile communications. In addition, the impact of user’s hand on the antenna performance has been investigated....... antennas have been compactly arranged along the edge region of the mobile phone PCB to form the antenna package. By switching the feeding to one of the sub arrays, the desired direction of coverage can be achieved. The proposed design has >10 dB gain in the upper spherical space, good directivity......This manuscript proposes a new design of a millimeter-wave (mm-Wave) array antenna package with beam steering characteristic for the fifth generation (5G) mobile applications. In order to achieve a broad 3D scanning coverage of the space with high-gain beams, three identical sub arrays of patch...

  8. 8×8 Planar Phased Array Antenna with High Efficiency and Insensitivity Properties for 5G Mobile Base Stations

    DEFF Research Database (Denmark)

    Ojaroudiparchin, Naser; Shen, Ming; Pedersen, Gert F.

    2016-01-01

    An insensitive planar phased array antenna with high efficiency function for 5G applications is introduced in this study. 64-elements of compact slot-loop antenna elements have been used to form the 8×8 planar array. The antenna is designed on a low cost FR4 substrate and has good performance in ...... at both sides of the substrate and could be used for mobile base station (MBS) applications. The proposed planar array could be integrated with the transceivers on the low-cost printed circuit boards (PCBs) to reduce the manufacturing cost....

  9. Design of Controller for Reducing In-Rush Current of Single-Phase Induction Motor

    Energy Technology Data Exchange (ETDEWEB)

    Park, Su Kang; Baek, Hyung Lae; Lee, Sang Il [Chosun University, Kwangju (Korea)

    2001-05-01

    During an AC motor's start-up accelerating period, a large amount of current is required to reach to the rating speed. This is called in-rush current. This peak in-rush current can be more than about several times the operating or steady-state current in the full load rating of the motor. In-rush current is present in both and electronic ballasts. The main area of concern is the tripping of circuit breaker and fuses which can affect electrical system components From this, we can see that the electrical power controllers will be rather concerned, since they have to supply the actual current necessary to start the motor. This paper presents a new method to reducing in-rush current and energy saving of the single-phase induction motor used in air-conditioner. It can be obtained that proposed system is low cost and small size as compared with other controller. Experiments are focused on a capacitor starting single-phase induction motor. The optimal power saving and in-rush current limiting by phase angle control are verified by experimental results. Also, auxiliary winding was controlled by electronic starting switch. (author). 10 refs., 13 figs., 2 tabs.

  10. Paramagnetism and antiferromagnetic interactions in single-phase Fe-implanted ZnO

    CERN Document Server

    Pereira, Lino Miguel da Costa; Correia, João Guilherme; Van Bael, M J; Temst, Kristiaan; Vantomme, André; Araújo, João Pedro

    2013-01-01

    As the intrinsic origin of the high temperature ferromagnetism often observed in wide-gap dilute magnetic semiconductors becomes increasingly debated, there is a growing need for comprehensive studies on the single-phase region of the phase diagram of these materials. Here we report on the magnetic and structural properties of Fe-doped ZnO prepared by ion implantation of ZnO single crystals. A detailed structural characterization shows that the Fe impurities substitute for Zn in ZnO in a wurtzite Zn$_{1−x}$Fe$_{x}$O phase which is coherent with the ZnO host. In addition, the density of beam-induced defects is progressively decreased by thermal annealing up to 900$^{\\circ}$C, from highly disordered after implantation to highly crystalline upon subsequent annealing. Based on a detailed analysis of the magnetometry data, we demonstrate that isolated Fe impurities occupying Zn substitutional sites behave as localized paramagnetic moments down to 2$^{\\circ}$K, irrespective of the Fe concentration and the density...

  11. Application of Phased Array Ultrasonic Testing (PAUT) on Single V-Butt Weld Integrity Determination

    International Nuclear Information System (INIS)

    Amry Amin Abas; Mohd Kamal Shah Shamsudin; Norhazleena Azaman

    2015-01-01

    Phased Array Ultrasonic Testing (PAUT) utilizes arrays of piezoelectric elements that are embedded in an epoxy base. The benefit of having such kind of array is that beam forming such as steering and focusing the beam front possible. This enables scanning patterns such as linear scan, sectorial scan and depth focusing scan to be performed. Ultrasonic phased array systems can potentially be employed in almost any test where conventional ultrasonic flaw detectors have traditionally been used. Weld inspection and crack detection are the most important applications, and these tests are done across a wide range of industries including aerospace, power generation, petrochemical, metal billet and tubular goods suppliers, pipeline construction and maintenance, structural metals, and general manufacturing. Phased arrays can also be effectively used to profile remaining wall thickness in corrosion survey applications. The benefits of PAUT are simplifying inspection of components of complex geometry, inspection of components with limited access, testing of welds with multiple angles from a single probe and increasing the probability of detection while improving signal-to-noise ratio. This paper compares the result of inspection on several specimens using PAUT as to digital radiography. The specimens are welded plates with single V-butt weld made of carbon steel. Digital radiography is done using blue imaging plate with x-ray source. PAUT is done using Olympus MX2 with 5 MHz probe consisting of 64 elements. The location, size and length of defect is compared. (author)

  12. Numerical investigation of refrigeration machine compressor operation considering single-phase electric motor dynamic characteristics

    Science.gov (United States)

    Baidak, Y.; Smyk, V.

    2017-08-01

    Using as the base the differential equations system which was presented in relative units for generalized electric motor of hermetic refrigeration compressor, mathematical model of the software for dynamic performance calculation of refrigeration machine compressors drive low-power asynchronous motors was developed. Performed on its ground calculations of the basic model of two-phase electric motor drive of hermetic compressor and the proposed newly developed model of the motor with single-phase stator winding, which is an alternative to the industrial motor winding, have confirmed the benefits of the motor with innovative stator winding over the base engine. Given calculations of the dynamic characteristics of compressor drive motor have permitted to determine the value of electromagnetic torque swinging for coordinating compressor and motor mechanical characteristics, and for taking them into consideration in choosing compressor elements construction materials. Developed and used in the process of investigation of refrigeration compressor drive asynchronous single-phase motor mathematical and software can be considered as an element of computer-aided design system for design of the aggregate of refrigeration compression unit refrigerating machine.

  13. Validation of CATHENA MOD-3.5/Rev0 for single-phase water hammer

    International Nuclear Information System (INIS)

    Beuthe, T.G.

    2000-01-01

    This paper describes work performed to validate the system thermalhydraulics code CATHENA MOD-3.5c/Rev0 for single-phase water hammer. Simulations were performed and are compared quantitatively against numerical tests and experimental results from the Seven Sisters Water Hammer Facility to demonstrate CATHENA can predict the creation and propagation of pressure waves when valves are opened and closed. Simulations were also performed to show CATHENA can model the behaviour of reflected and transmitted pressure waves at area changes, dead ends, tanks, boundary conditions, and orifices in simple and more complex piping systems. The CATHENA results are shown to calculate pressure and wave propagation speeds to within 0.2% and 0.5% respectively for numerical tests and within 3.3% and 5% for experimental results respectively. These results are used to help validate CATHENA for use in single-phase water hammer analysis. They also provide assurance that the fundamental parameters needed to successfully model more complex forms of water hammer are accounted for in the MOD-3.5c/Rev0 version of CATHENA, and represent the first step in the process to validate the code for use in modelling two-phase water hammer and condensation-induced water hammer. (author)

  14. Magnetic phase transitions in Er7Rh3 studied on single crystals

    International Nuclear Information System (INIS)

    Tsutaoka, Takanori; Obata, Keisuke; Cheyvuth, Seng; Koyama, Keiichi

    2014-01-01

    Highlights: • Magnetic and electrical properties of Er 7 Rh 3 were studied on single crystals. • The magnetic phase diagram along the c-axis was constructed. • The field-induced magnetic transitions in Er 7 Rh 3 can be explained by the magnetic structure with two magnetic propagation vectors. • The anomalies of electrical resistivity can also be described by the magnetic structure in Er 7 Rh 3 . - Abstract: Magnetic phase transitions in Er 7 Rh 3 with the Th 7 Fe 3 type hexagonal structure have been studied on single crystals by measuring magnetization, magnetic susceptibility and electrical resistivity. Er 7 Rh 3 possesses antiferromagnetic state below T N = 13 K. In the ordered state, the two successive magnetic transitions at T t1 = 6.2 K and T t2 = 4.5 K were observed. Several field-induced magnetic transitions were also observed along the a- and c-axes below T N ; magnetic field H – temperature T phase diagram along the c-axis was constructed. The field-induced magnetic transitions in Er 7 Rh 3 can be explained by the magnetic structure with two magnetic propagation vectors which were derived by the previous neutron diffraction studies. Electrical resistivity shows humps just below the magnetic transition temperatures, T N and T t1 due to the super-zone gap formation at the Fermi level; these anomalies can also be described by the magnetic structure changes in Er 7 Rh 3

  15. FUZZY LOGIC BASED OPTIMIZATION OF CAPACITOR VALUE FOR SINGLE PHASE OPEN WELL SUBMERSIBLE INDUCTION MOTOR

    Directory of Open Access Journals (Sweden)

    R. Subramanian

    2011-01-01

    Full Text Available Purpose – The aim of this paper is to optimize the capacitor value of a single phase open well submersible motor operating under extreme voltage conditions using fuzzy logic optimization technique and compared with no-load volt-ampere method. This is done by keeping the displacement angle (a between main winding and auxiliary winding near 90o, phase angle (f between the supply voltage and line current near 0o. The optimization work is carried out by using Fuzzy Logic Toolbox software built on the MATLAB technical computing environment with Simulink software. Findings – The optimum capacitor value obtained is used with a motor and tested for different supply voltage conditions. The vector diagrams obtained from the experimental test results indicates that the performance is improved from the existing value. Originality/value – This method will be highly useful for the practicing design engineers in selecting the optimum capacitance value for single phase induction motors to achieve the best performance for operating at extreme supply voltage conditions.

  16. Mobility and height detection of particle labels in an optical evanescent wave biosensor with single-label resolution

    Energy Technology Data Exchange (ETDEWEB)

    Van Ommering, Kim; Koets, Marjo; Schleipen, Jean J H B; Prins, Menno W J [Philips Research Laboratories, 5656 AE Eindhoven (Netherlands); Somers, Philip A; Van IJzendoorn, Leo J, E-mail: menno.prins@philips.co [Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands)

    2010-04-21

    Particle labels are used in biosensors to detect the presence and concentration of analyte molecules. In this paper we demonstrate an optical technique to measure the mobility and height of bound particle labels on a biosensor surface with single-label resolution. The technique is based on the detection of the particle-induced light scattering in an optical evanescent field. We show that the thermal particle motion in the optical evanescent field leads to intensity fluctuations that can accurately be detected. The technique is demonstrated using 290 bp (99 nm) DNA as an analyte and using polystyrene particles and magnetic particles with diameters between 500 and 1000 nm as labels. The particle intensity histograms show that quantitative height measurements are obtained for particles with uniform optical properties, and the intensity versus position plots reflect the analyte-antibody orientation and the analyte flexibility. The novel optical detection technique will lead to biosensors with very high sensitivity and specificity.

  17. A High-Rate, Single-Crystal Model including Phase Transformations, Plastic Slip, and Twinning

    Energy Technology Data Exchange (ETDEWEB)

    Addessio, Francis L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Bronkhorst, Curt Allan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Bolme, Cynthia Anne [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Explosive Science and Shock Physics Division; Brown, Donald William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Cerreta, Ellen Kathleen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Lebensohn, Ricardo A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Lookman, Turab [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Luscher, Darby Jon [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Mayeur, Jason Rhea [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Theoretical Division; Morrow, Benjamin M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Materials Science and Technology Division; Rigg, Paulo A. [Washington State Univ., Pullman, WA (United States). Dept. of Physics. Inst. for Shock Physics

    2016-08-09

    An anisotropic, rate-­dependent, single-­crystal approach for modeling materials under the conditions of high strain rates and pressures is provided. The model includes the effects of large deformations, nonlinear elasticity, phase transformations, and plastic slip and twinning. It is envisioned that the model may be used to examine these coupled effects on the local deformation of materials that are subjected to ballistic impact or explosive loading. The model is formulated using a multiplicative decomposition of the deformation gradient. A plate impact experiment on a multi-­crystal sample of titanium was conducted. The particle velocities at the back surface of three crystal orientations relative to the direction of impact were measured. Molecular dynamics simulations were conducted to investigate the details of the high-­rate deformation and pursue issues related to the phase transformation for titanium. Simulations using the single crystal model were conducted and compared to the high-­rate experimental data for the impact loaded single crystals. The model was found to capture the features of the experiments.

  18. Single-crystal FCC and DHCP phases in Ce/Pr superlattices

    International Nuclear Information System (INIS)

    Lee, S.; Goff, J.P.; Ward, R.C.C.; Wells, M.R.; McIntyre, G.J.

    2002-01-01

    Cerium usually comprises a mixture of polycrystalline FCC and DHCP allotropes. Single-crystal Ce has been stabilised in Ce/Pr superlattices grown using molecular beam epitaxy. It is found that FCC or DHCP phases can be obtained depending on superlattice composition and growth conditions. Low-temperature neutron scattering was performed on Ce/Pr samples using the triple-axis spectrometer D10 at the ILL. Such measurements revealed one sample, [Ce 20 Pr 20 ] 60 , to be a single crystal with a DHCP unit cell; while another, [Ce 30 Pr 10 ] 56 , was a mixture of FCC and DHCP phases. Antiferromagnetic ordering of magnetic moments was observed in the DHCP sample (T N =11.1 K) with a magnetic structure similar to that found in bulk β-Ce. Surprisingly, the magnetic ordering was found to be confined to single Ce blocks. Furthermore, it was found that, at low temperatures, the lattice contraction observed for bulk FCC Ce was suppressed in Ce/Pr superlattices. (orig.)

  19. Growth of single crystalline seeds into polycrystalline strontium titanate: Anisotropy of the mobility, intrinsic drag effects and kinetic shape of grain boundaries

    International Nuclear Information System (INIS)

    Rheinheimer, Wolfgang; Bäurer, Michael; Handwerker, Carol A.; Blendell, John E.; Hoffmann, Michael J.

    2015-01-01

    We present a suite of measurements and combined analyses of grain growth in SrTiO 3 for oriented single crystals into polycrystals. The growth distance and standard deviation and the microstructure evolution along the single crystal–matrix interface are used to locally characterize the change in migration behavior as a function of temperature, time and interface orientation. The relative grain boundary mobility was determined between 1250 °C and 1600 °C for four crystallographic orientations {1 0 0}, {1 1 0}, {1 1 1} and {3 1 0}. An absolute mobility of these orientations is estimated. Under fast growth conditions the morphology of single crystals shows macroscopic stepping with parts of the interface rotating to low mobility orientations. This effect represents a kinetic influence on the grain boundary morphology. The results also indicate dragging effects on microstructure coarsening, which indicate the existence of a critical driving force for grain growth. This critical driving force seems to be related to an ‘intrinsic’ interface drag similar to the solute drag, but based on intrinsic defects. At 1460 °C the growth of single crystals was significantly faster than expected from the mobility of the polycrystal and was identified as exaggerated grain growth. The findings give new insights into the recently published grain growth anomaly of strontium titanate, leading to a hypothesis based on the temperature dependent relative mobility of {1 0 0} oriented grain boundaries

  20. Phase Locking of Multiple Single Neurons to the Local Field Potential in Cat V1.

    Science.gov (United States)

    Martin, Kevan A C; Schröder, Sylvia

    2016-02-24

    The local field potential (LFP) is thought to reflect a temporal reference for neuronal spiking, which may facilitate information coding and orchestrate the communication between neural populations. To explore this proposed role, we recorded the LFP and simultaneously the spike activity of one to three nearby neurons in V1 of anesthetized cats during the presentation of drifting sinusoidal gratings, binary dense noise stimuli, and natural movies. In all stimulus conditions and during spontaneous activity, the average LFP power at frequencies >20 Hz was higher when neurons were spiking versus not spiking. The spikes were weakly but significantly phase locked to all frequencies of the LFP. The average spike phase of the LFP was stable across high and low levels of LFP power, but the strength of phase locking at low frequencies (≤10 Hz) increased with increasing LFP power. In a next step, we studied how strong stimulus responses of single neurons are reflected in the LFP and the LFP-spike relationship. We found that LFP power was slightly increased and phase locking was slightly stronger during strong compared with weak stimulus-locked responses. In summary, the coupling strength between high frequencies of the LFP and spikes was not strongly modulated by LFP power, which is thought to reflect spiking synchrony, nor was it strongly influenced by how strongly the neuron was driven by the stimulus. Furthermore, a comparison between neighboring neurons showed no clustering of preferred LFP phase. We argue that hypotheses on the relevance of phase locking in their current form are inconsistent with our findings. Copyright © 2016 the authors 0270-6474/16/362494-09$15.00/0.

  1. The use of phase sequence image sets to reconstruct the total volume occupied by a mobile lung tumor

    International Nuclear Information System (INIS)

    Gagne, Isabelle M.; Robinson, Don M.; Halperin, Ross; Roa, Wilson

    2005-01-01

    The use of phase sequence image (PSI) sets to reveal the total volume occupied by a mobile target is presented. Isocontrast composite clinical target volumes (CCTVs) may be constructed from PSI sets in order to reveal the total volume occupied by a mobile target during the course of its travel. The ability of the CCTV technique to properly account for target motion is demonstrated by comparison to contours of the true total volume occupied (TVO) for a number of experimental phantom geometries. Finally, using real patient data, the clinical utility of the CCTV technique to properly account for internal tumor motion while minimizing the volume of healthy lung tissue irradiated is assessed by comparison to the standard approach of applying safety margins. Results of the phantom study reveal that CCTV cross sections constructed at the 20% isocontrast level yield good agreement with the total cross sections (TXO) of mobile targets. These CCTVs conform well to the TVOs of the moving targets examined whereby the addition of small uniform margins ensures complete circumscription of the TVO with the inclusion of minimal amounts of surrounding external volumes. The CCTV technique is seen to be clearly superior to the common practice of the addition of safety margins to individual CTV contours in order to account for internal target motion. Margins required with the CCTV technique are eight to ten times smaller than those required with individual CTVs

  2. A PWM strategy for acoustic noise reduction for grid-connected single-phase inverters

    Energy Technology Data Exchange (ETDEWEB)

    Shao, R.; Guo, Z.; Chang, L. [New Brunswick Univ., Fredericton, NB (Canada). Dept. of Electrical and Computer Engineering

    2006-07-01

    This paper presented a newly proposed and improved pulse width modulation (PWM) strategy for grid-connected single-phase inverters. Small distributed generators using energy from renewable resources such as PV and wind systems typically use grid-connected single-phase inverters as voltage source inverters for good acoustic performance. PWM is generally applied in these inverters in order to achieve good waveforms of output current as required by interconnection standards. In routine simultaneous switching PWM methods, the current ripples through the inverter output filter inductor are at the carrier switching frequency, which is one of the major causes for inverter acoustic noise. The new PWM strategy effectively alleviates acoustic noise and improves output power quality. It is based on the principle of evenly splitting the switching of Insulated Gate Bipolar Transistors (IGBT) in each switching cycle among all IGBTs of the full bridge, thereby using a non-simultaneous mode of PWM which doubles the output current ripple frequency. This increases the inductor current ripple frequency to twice the carrier frequency. It is therefore possible to increase the current ripple frequency, or noise frequency into the range of ultrasonic which is inaudible to the human ear, without increasing the inverter's switching frequency to which the inverter's switching loss is proportional. In addition, this new PWM scheme can reduce the output current harmonics distortion and dc link current ripples. As such, lower capacitance in dc link capacitors and lower inductance of output inductor are needed. The improved PWM scheme was verified in a 3 kW grid-connected single-phase inverter. It was shown that the PWM strategy can be readily implemented with a digital signal processing microcontroller. 8 refs., 11 figs.

  3. Reactive Power Injection Strategies for Single-Phase Photovoltaic Systems Considering Grid Requirements

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

    2014-01-01

    .g. Germany and Italy. Those advanced features can be provided by next generation PV systems, and will be enhanced in the future to ensure an even efficient and reliable utilization of PV systems. In light of this, Reactive Power Injection (RPI) strategies for single-phase PV systems are explored...... in this paper. The RPI possibilities are: a) constant average active power control, b) constant active current control, c) constant peak current control and d) thermal optimized control strategy. All those strategies comply with the currently active grid codes, but are with different objectives. The proposed...... RPI strategies are demonstrated firstly by simulations and also tested experimentally on a 1 kW singe-phase grid-connected system in LVRT operation mode. Those results show the effectiveness and feasibilities of the proposed strategies with reactive power control during LVRT operation. The design...

  4. Phase Portraits of the Autonomous Duffing Single-Degree-of-Freedom Oscillator with Coulomb Dry Friction

    Directory of Open Access Journals (Sweden)

    Nikola Jakšić

    2014-01-01

    Full Text Available The paper presents phase portraits of the autonomous Duffing single-degree-of-freedom system with Coulomb dry friction in its δ-γ-ε parameter space. The considered nonlinearities of the cubic stiffness (ε and Coulomb dry friction (γ are widely used throughout the literature. It has been shown that there can be more than one sticking region in the phase plane. It has also been shown that an equilibrium point occurs at the critical combinations of values of the parameters γ and ε which gives rise to zero eigenvalue of the linearised system. The unstable limit cycle may appear in the case of negative viscous damping (δ; δ<0.

  5. Quantum sensing of the phase-space-displacement parameters using a single trapped ion

    Science.gov (United States)

    Ivanov, Peter A.; Vitanov, Nikolay V.

    2018-03-01

    We introduce a quantum sensing protocol for detecting the parameters characterizing the phase-space displacement by using a single trapped ion as a quantum probe. We show that, thanks to the laser-induced coupling between the ion's internal states and the motion mode, the estimation of the two conjugated parameters describing the displacement can be efficiently performed by a set of measurements of the atomic state populations. Furthermore, we introduce a three-parameter protocol capable of detecting the magnitude, the transverse direction, and the phase of the displacement. We characterize the uncertainty of the two- and three-parameter problems in terms of the Fisher information and show that state projective measurement saturates the fundamental quantum Cramér-Rao bound.

  6. Reliable Grid Condition Detection and Control of Single-Phase Distributed Power Generation Systems

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai

    standards addressed to the grid-connected systems will harmonize the combination of the DPGS and the classical power plants. Consequently, the major tasks of this thesis were to develop new grid condition detection techniques and intelligent control in order to allow the DPGS not only to deliver power...... to the utility grid but also to sustain it. This thesis was divided into two main parts, namely "Grid Condition Detection" and "Control of Single-Phase DPGS". In the first part, the main focus was on reliable Phase Locked Loop (PLL) techniques for monitoring the grid voltage and on grid impedance estimation...... techniques. Additionally, a new technique for detecting the islanding mode has been developed and successfully tested. In the second part, the main reported research was concentrated around adaptive current controllers based on the information provided by the grid condition detection techniques. To guarantee...

  7. Green synthesis of isopropyl myristate in novel single phase medium Part I: Batch optimization studies.

    Science.gov (United States)

    Vadgama, Rajeshkumar N; Odaneth, Annamma A; Lali, Arvind M

    2015-12-01

    Isopropyl myristate finds many applications in food, cosmetic and pharmaceutical industries as an emollient, thickening agent, or lubricant. Using a homogeneous reaction phase, non-specific lipase derived from Candida antartica, marketed as Novozym 435, was determined to be most suitable for the enzymatic synthesis of isopropyl myristate. The high molar ratio of alcohol to acid creates novel single phase medium which overcomes mass transfer effects and facilitates downstream processing. The effect of various reaction parameters was optimized to obtain a high yield of isopropyl myristate. Effect of temperature, agitation speed, organic solvent, biocatalyst loading and batch operational stability of the enzyme was systematically studied. The conversion of 87.65% was obtained when the molar ratio of isopropyl alcohol to myristic acid (15:1) was used with 4% (w/w) catalyst loading and agitation speed of 150 rpm at 60 °C. The enzyme has also shown good batch operational stability under optimized conditions.

  8. Zero-voltage ride-through capability of single-phase grid-connected photovoltaic systems

    DEFF Research Database (Denmark)

    Zhang, Zhen; Yang, Yongheng; Ma, Ruiqing

    2017-01-01

    Distributed renewable energy systems play an increasing role in today’s energy paradigm. Thus, intensive research activities have been centered on improving the performance of renewable energy systems, including photovoltaic (PV) systems, which should be of multiple-functionality. That is, the PV...... systems should be more intelligent in the consideration of grid stability, reliability, and fault protection. Therefore, in this paper, the performance of single-phase grid-connected PV systems under an extreme grid fault (i.e., when the grid voltage dips to zero) is explored. It has been revealed...... that combining a fast and accurate synchronization mechanism with appropriate control strategies for the zero-voltage ride-through (ZVRT) operation is mandatory. Accordingly, the representative synchronization techniques (i.e., the phase-locked loop (PLL) methods) in the ZVRT operation are compared in terms...

  9. Conceptual Design of a Single Phase 33 MVA HTS Transformer with a Tertiary Winding

    International Nuclear Information System (INIS)

    Lee, S. W.; Kim, W. S.; Hahn, S. Y.; Hwang, Y. I.; Choi, K. D.

    2006-01-01

    We have proposed a 3 phase, 100 MVA, 154 kV class HTS transformer substituting for a 60 MVA conventional transformer. The power transformer of 154 kV class has a tertiary winding besides primary and secondary windings. So the HTS transformer should have the 3rd superconducting winding. In this paper, we designed conceptually the structure of the superconducting windings of a single phase 33 MVA transformer. The electrical characteristics of the HTS transformer such as % impedance and AC loss vary with the arrangement of the windings and gaps between windings. We analyzed the effects of the winding parameters, evaluated the cost of each design, and proposed a suitable HTS transformer model for future power distribution system.

  10. Phase transitions in trajectories of a superconducting single-electron transistor coupled to a resonator.

    Science.gov (United States)

    Genway, Sam; Garrahan, Juan P; Lesanovsky, Igor; Armour, Andrew D

    2012-05-01

    Recent progress in the study of dynamical phase transitions has been made with a large-deviation approach to study trajectories of stochastic jumps using a thermodynamic formalism. We study this method applied to an open quantum system consisting of a superconducting single-electron transistor, near the Josephson quasiparticle resonance, coupled to a resonator. We find that the dynamical behavior shown in rare trajectories can be rich even when the mean dynamical activity is small, and thus the formalism gives insights into the form of fluctuations. The structure of the dynamical phase diagram found from the quantum-jump trajectories of the resonator is studied, and we see that sharp transitions in the dynamical activity may be related to the appearance and disappearance of bistabilities in the state of the resonator as system parameters are changed. We also demonstrate that for a fast resonator, the trajectories of quasiparticles are similar to the resonator trajectories.

  11. Precision in single atom localization via Raman-driven coherence: Role of detuning and phase shift

    Energy Technology Data Exchange (ETDEWEB)

    Rahmatullah,; Qamar, Sajid, E-mail: sajid_qamar@comsats.edu.pk

    2013-10-01

    Role of detuning and phase shift associated with the standing-wave driving fields is revisited for precision position measurement of single atom during its motion through two standing-wave fields. A four-level atomic system in diamond configuration is considered where the intermediate levels are coupled to upper and lower level via standing-wave driving fields and atomic decay channels, respectively. The former is responsible for the generation of quantum mechanical coherence via two-photon Raman transition while the latter leads to spontaneous emission of a photon. Due to standing-wave driving fields the atom–field interaction becomes position-dependent and measurement of the frequency of spontaneously emitted photon gives the position information of the atom. The unique position of the atom with much higher spatial resolution, i.e., of the order of λ/100 is observed using detuning and phase shift associated with the standing-wave driving fields.

  12. Mechanism of falling water limitation in two-phase counter flow through single hole vertical channel

    International Nuclear Information System (INIS)

    Sudo, Yukio; Ohnuki, Akira

    1983-01-01

    In the safety evaluation at the time of loss coolant accident, which is a credible accident in LWRs, recently main effort has been concentrated to the optimum evaluation calculation, and the grasp of vapor-liquid two-phase flow phenomena has become important. As one of the important phenomena, there is the limitation of falling water in two-phase counter flow through a vertical channel. This phenomenon is divided into the limitation of falling water stored in an upper plenum to a core through an upper core-supporting plate and a tie plate at the time of reflooding, and the limitation of falling emergency core-cooling water in downcomer channels at the time of reflooding in PWRs, under the presence of rising steam flow. In both cases, the evaluation of the quantity of falling water is important, because it contributes directly to core cooling. In this research, in order to clarify the mechanism of limitation of falling water in two-phase vertical counter flow, first, two-phase flow of air-water system through a single-hole vertical channel was taken up, and the effect of main parameters was experimentally studied. At the same time, the theoretical investigation was performed, and the comparison with the experimental results obtained so far was carried out. The different mechanisms for short and long channels gave the good results. (Kako, I.)

  13. Reliability-Oriented Design and Analysis of Input Capacitors in Single-Phase Transformer-less Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Wang, Huai; Yang, Yongheng; Blaabjerg, Frede

    2013-01-01

    While 99% efficiency has been reported, the target of 20 years of service time imposes new challenge to cost-effective solutions for grid-connected photovoltaic (PV) inverters. Aluminum electrolytic capacitors are the weak-link in terms of reliability and lifetime in single-phase PV systems....... A reliability-oriented design guideline is proposed in this paper for the input capacitors in single-phase transformer-less PV inverters. The guideline ensures that the service time requirement is to be accomplished under different power levels and ambient temperature profiles. The theoretical analysis has been...... demonstrated by a 1 kW single-phase PV inverter....

  14. Factors that affect the calibration of turbines in single-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Piper, T. C.

    1977-05-01

    Basic turbine operation in single-phase flow is related. Causes and relative magnitudes of retarding torque are given for two sizes of turbines when used for water flow measurement. An equation for slip caused by retarding torques is given. Evaluation of turbine slip behavior at the turbine low flow region shows that bearing retarding torques, change in flow patterns, or other effects can predominate in the relatively large changes in the calibration ''constant'' that occurs there. Fluid lubricity is singled out as an important fluid property in certain types of bearings and flow. Temperature induced changes in turbine size are shown to cause calibration changes if a turbine is used at a temperature significantly different than that at which it was calibrated.

  15. Solid-phase single molecule biosensing using dual-color colocalization of fluorescent quantum dot nanoprobes

    Science.gov (United States)

    Liu, Jianbo; Yang, Xiaohai; Wang, Kemin; Wang, Qing; Liu, Wei; Wang, Dong

    2013-10-01

    The development of solid-phase surface-based single molecule imaging technology has attracted significant interest during the past decades. Here we demonstrate a sandwich hybridization method for highly sensitive detection of a single thrombin protein at a solid-phase surface based on the use of dual-color colocalization of fluorescent quantum dot (QD) nanoprobes. Green QD560-modified thrombin binding aptamer I (QD560-TBA I) were deposited on a positive poly(l-lysine) assembled layer, followed by bovine serum albumin blocking. It allowed the thrombin protein to mediate the binding of the easily detectable red QD650-modified thrombin binding aptamer II (QD650-TBA II) to the QD560-TBA I substrate. Thus, the presence of the target thrombin can be determined based on fluorescent colocalization measurements of the nanoassemblies, without target amplification or probe separation. The detection limit of this assay reached 0.8 pM. This fluorescent colocalization assay has enabled single molecule recognition in a separation-free detection format, and can serve as a sensitive biosensing platform that greatly suppresses the nonspecific adsorption false-positive signal. This method can be extended to other areas such as multiplexed immunoassay, single cell analysis, and real time biomolecule interaction studies.The development of solid-phase surface-based single molecule imaging technology has attracted significant interest during the past decades. Here we demonstrate a sandwich hybridization method for highly sensitive detection of a single thrombin protein at a solid-phase surface based on the use of dual-color colocalization of fluorescent quantum dot (QD) nanoprobes. Green QD560-modified thrombin binding aptamer I (QD560-TBA I) were deposited on a positive poly(l-lysine) assembled layer, followed by bovine serum albumin blocking. It allowed the thrombin protein to mediate the binding of the easily detectable red QD650-modified thrombin binding aptamer II (QD650-TBA II) to

  16. Factors that affect the calibration of turbines in single-phase flow

    International Nuclear Information System (INIS)

    Piper, T.C.

    1977-05-01

    Basic turbine operation in single-phase flow is related. Causes and relative magnitudes of retarding torque are given for two sizes of turbines when used for water flow measurement. An equation for slip caused by retarding torques is given. Evaluation of turbine slip behavior at the turbine low flow region shows that bearing retarding torques, change in flow patterns, or other effects can predominate in the relatively large changes in the calibration ''constant'' that occurs there. Fluid lubricity is singled out as an important fluid property in certain types of bearings and flow. Temperature induced changes in turbine size are shown to cause calibration changes if a turbine is used at a temperature significantly different than that at which it was calibrated

  17. Sliding three-phase contact line of printed droplets for single-crystal arrays

    International Nuclear Information System (INIS)

    Kuang, Minxuan; Wu, Lei; Li, Yifan; Gao, Meng; Zhang, Xingye; Jiang, Lei; Song, Yanlin

    2016-01-01

    Controlling the behaviours of printed droplets is an essential requirement for inkjet printing of delicate three-dimensional (3D) structures or high-resolution patterns. In this work, molecular deposition and crystallization are regulated by manipulating the three-phase contact line (TCL) behaviour of the printed droplets. The results show that oriented single-crystal arrays are fabricated based on the continuously sliding TCL. Owing to the sliding of the TCL on the substrate, the outward capillary flow within the evaporating droplet is suppressed and the molecules are brought to the centre of the droplet, resulting in the formation of a single crystal. This work provides a facile strategy for controlling the structures of printed units by manipulating the TCL of printed droplets, which is significant for realizing high-resolution patterns and delicate 3D structures. (paper)

  18. A Robust DC-Split-Capacitor Power Decoupling Scheme for Single-Phase Converter

    DEFF Research Database (Denmark)

    Yao, Wenli; Loh, Poh Chiang; Tang, Yi

    2017-01-01

    Instead of bulky electrolytic capacitors, active power decoupling circuit can be introduced to a single-phase converter for diverting second harmonic ripple away from its dc source or load. One possible circuit consists of a half-bridge and two capacitors in series for forming a dc-split capacitor......, instead of the usual single dc-link capacitor bank. Methods for regulating this power decoupler have earlier been developed, but almost always with equal capacitances assumed for forming the dc-split capacitor, even though it is not realistic in practice. The assumption should, hence, be evaluated more...... thoroughly, especially when it is shown in the paper that even a slight mismatch can render the power decoupling scheme ineffective and the IEEE 1547 standard to be breached. A more robust compensation scheme is, thus, needed for the dc-split capacitor circuit, as proposed and tested experimentally...

  19. Phase diagram of the Ge-rich of the Ba–Ge system and characterisation of single-phase BaGe4

    International Nuclear Information System (INIS)

    Prokofieva, Violetta K.; Pavlova, Lydia M.

    2014-01-01

    Highlights: • The Ba-Ge phase diagram for the range 50–100 at.% Ge was constructed. • Single-phase BaGe 4 grown by the Czochralski method was characterised. • A phenomenological model for a liquid-liquid phase transition is proposed. - Abstract: The Ba–Ge binary system has been investigated by several authors, but some uncertainties remain regarding phases with Ba/Ge ⩽ 2. The goal of this work was to resolve the uncertainty about the current phase diagram of Ba–Ge by performing DTA, X-ray powder diffraction, metallographic and chemical analyses, and measurements of the electrical conductivity and viscosity. The experimental Ba–Ge phase diagram over the composition range of 50–100 at.% Ge was constructed from the cooling curves and single-phase BaGe 4 grown by the Czochralski crystal pulling method was characterised. Semiconducting BaGe 4 crystallised peritectically from the liquid phase near the eutectic. In the liquid state, the caloric effects were observed in the DTA curves at 1050 °C where there are no definite phase lines in the Ba–Ge phase diagram. These effects are confirmed by significant changes in the viscosity and electrical conductivity of a Ba–Ge alloy with eutectic composition at this temperature. A phenomenological model based on two different approaches, a phase approach and a chemical approach, is proposed to explain the isothermal liquid–liquid phase transition observed in the Ba–Ge system from the Ge side. Our results suggest that this transition is due to the peritectic reactions in the liquid phase. This reversible phase transition results in the formation of precursors of various metastable clathrate phases and is associated with sudden changes in the structure of Ba–Ge liquid alloys. Characteristics of both first- and second-order phase transitions are observed. Charge transfer appears to play an important role in this transition

  20. Physicomechanical properties of single- and two-phase polycrystalline materials on micro- and macroscopic levels

    International Nuclear Information System (INIS)

    Kuksa, L.V.; Arzamaskova, L.M.

    2000-01-01

    The results of studies on elastic and plastic properties of the single- and two-phase polycrystalline materials in dependence on the choice of the consideration scale level are presented. The experimental and theoretical methods, making it possible to study the role of the scale factor by consideration on the micro- and macrolevel and the peculiarities of forming the physicomechanical properties of the material as a whole, are developed. The dependences, characterizing the change of the physicomechanical properties by different scales of consideration, are obtained [ru

  1. Indirect Control of a low power Single-Phase Active Power Filter

    Directory of Open Access Journals (Sweden)

    SILVIU EPURE

    2010-12-01

    Full Text Available This paper deals with a low power, single phase active filter used to compensate nonlinear loads. The filter uses the indirect control method and it is based on a particular connection between filter, polluting load and grid to avoid timeconsuming mathematic operations or signal processing computations and assures good rejection of harmonic currents injected by the nonlinear load into the grid. A scale model was first simulated in Simulink and then physically implemented. The paper presents simulation and experimental results, and highlight problems encountered during experiments.

  2. Pressure-induced phase transitions in single-crystalline Cu4Bi4S9 nanoribbons

    International Nuclear Information System (INIS)

    Hu Jing-Yu; Li Jing; Zhao Qing; Shi Li-Jie; Zou Bing-Suo; Zhang Si-Jia; Zhao Hao-Fei; Zhang Qing-Hua; Yao Yuan; Zhu Ke; Liu Yu-Long; Jin Chang-Qing; Yu Ri-Cheng; Li Yan-Chun; Li Xiao-Dong; Liu Jing

    2013-01-01

    In situ angle dispersive synchrotron X-ray diffraction and Raman scattering measurements under pressure are employed to study the structural evolution of Cu 4 Bi 4 S 9 nanoribbons, which are fabricated by using a facile solvothermal method. Both experiments show that a structural phase transition occurs near 14.5 GPa, and there is a pressure-induced reversible amorphization at about 25.6 GPa. The electrical transport property of a single Cu 4 Bi 4 S 9 nanoribbon under different pressures is also investigated

  3. Detection and characterization of single nanoparticles by interferometric phase modulated ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Barroso, F.; Bosch, S.; Tort, N.; Arteaga, O. [Universitat de Barcelona, IN2UB, Dep. Fisica Aplicada i Optica, c/Marti i Franques 1, 08028 (Spain); Sancho-Parramon, J. [Rudjer Boskovic Institute, Bijenicka c. 54, Zagreb 10002 (Croatia); Jover, E.; Bertran, E. [Universitat de Barcelona, IN2UB, Dep. Fisica Aplicada i Optica, c/Marti i Franques 1, 08028 (Spain); Canillas, A., E-mail: acanillas@ub.ed [Universitat de Barcelona, IN2UB, Dep. Fisica Aplicada i Optica, c/Marti i Franques 1, 08028 (Spain)

    2011-02-28

    We introduce a new measurement system called Nanopolar interferometer devoted to monitor and characterize single nanoparticles which is based on the interferometric phase modulated ellipsometry technique. The system collects the backscattered light by the particles in the solid angle subtended by a microscope objective and then analyses its frequency components. The results for the detection of 2 {mu}m and 50 nm particles are explained in terms of a cross polarization effect of the polarization vectors when the beam converts from divergent to parallel in the microscope objective. This explanation is supported with the results of the optical modelling using the exact Mie theory for the light scattered by the particles.

  4. A Novel Flying Capacitor Transformerless Inverter for Single-Phase Grid Connected Solar Photovoltaic System

    DEFF Research Database (Denmark)

    Siwakoti, Yam Prasad; Blaabjerg, Frede

    2016-01-01

    This paper proposes a new single-phase flying capacitor transformerless PV inverter for grid-connected photovoltaic (PV) systems. The neutral of the grid can be directly connected to the negative terminal of the source (PV). It consists of four power switches, one diode, one capacitor and a small...... and some topologies, which requires two times of the peak ac-voltage magnitude) and, (5) the flying capacitor charges every switching cycle, which reduces the size of the required capacitor with switching frequency. In addition, industry standard half bridge module can be used in the new inverter without...

  5. S4 Grid-Connected Single-Phase Transformerless Inverter for PV Application

    DEFF Research Database (Denmark)

    Ardashir, Jaber Fallah; Siwakoti, Yam Prasad; Sabahi, Mehran

    2016-01-01

    This paper introduces a new single-phase transformerless inverter for grid-connected photovoltaic systems with low leakage current. It consists of four power switches, two diodes, two capacitors and a filter at the output stage. The neutral of the grid is directly connected to the negative terminal...... size, low cost, flexible grounding configuration and higher efficiency. The operating principle and analysis of the proposed circuit are presented in details. Experimental results of a 500 W prototype are demonstrated to validate the proposed topology and the overall concept. The results obtained...... clearly verify the performance of the proposed inverter and its practical application for grid-connected PV systems....

  6. Sampling device for withdrawing a representative sample from single and multi-phase flows

    Science.gov (United States)

    Apley, Walter J.; Cliff, William C.; Creer, James M.

    1984-01-01

    A fluid stream sampling device has been developed for the purpose of obtaining a representative sample from a single or multi-phase fluid flow. This objective is carried out by means of a probe which may be inserted into the fluid stream. Individual samples are withdrawn from the fluid flow by sampling ports with particular spacings, and the sampling parts are coupled to various analytical systems for characterization of the physical, thermal, and chemical properties of the fluid flow as a whole and also individually.

  7. Low voltage ride-through of single-phase transformerless photovoltaic inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Wang, Huai

    2013-01-01

    Transformerless photovoltaic (PV) inverters are going to be more widely adopted in order to achieve high efficiency, as the penetration level of PV systems is continuously booming. However, problems may arise in highly PV-integrated distribution systems. For example, a sudden stoppage of all PV...... discussed. The selected inverters are the full-bridge inverter with bipolar modulation, full-bridge inverter with DC bypass and the Highly Efficient and Reliable Inverter Concept (HERIC). A 1 kW single-phase grid-connected PV system is analyzed to verify the discussions. The tests confirmed that, although...

  8. H-Bridge Transformerless Inverter with Common Ground for Single-Phase Solar-Photovoltaic System

    DEFF Research Database (Denmark)

    Siwakoti, Yam Prasad; Blaabjerg, Frede

    2017-01-01

    This paper proposes a new single-phase H-Bridge transformerless inverter with common ground for grid-connected photovoltaic systems (hereafter it is called ‘Siwakoti-H’ inverter). The inverter works on the principle of flying capacitor and consists of only four power switches (two reverse blocking...... IGBT's (RB-IGBT) and two MOSFET's), a capacitor and a small filter at the output stage. The proposed topology share a common ground with the grid and the PV source. A Unipolar Sinusoidal Pulse-Width Modulation (SPWM) technique is used to modulate the inverter to minimize switching loss, output current...

  9. Pressure drop and heat transfer of lithium single-phase flow under transverse magnetic field

    International Nuclear Information System (INIS)

    Takahashi, Minoru; Aritomi, Masanori; Inoue, Akira; Matsuzaki, Mitsuo

    1996-01-01

    Pressure drop and heat transfer characteristics of a lithium single-phase flow in a rectangular channel was investigated experimentally in the presence of a magnetic field. Friction loss coefficient under non-magnetic field and skin friction coefficient under magnetic field agreed well with the Blasius formula and a simple analytical expression, respectively. Nusselt number under non-magnetic field was slightly lower than the correlation by Hartnett and Irvine. Heat transfer was enhanced by increasing magnetic field above the Hartmann number of about 200. (author)

  10. Single-crystal neutron diffraction study of ammonium nitrate phase III

    International Nuclear Information System (INIS)

    Choi, C.S.; Prask, H.J.

    1982-01-01

    The crystal structure of ammonium nitrate phase III has been studied at room temperature by neutron diffraction using a single crystal containing 5% KNO 3 in solid-solution form. The space group is Pnma, with a = 7.6772 (4), b = 5.8208 (4), c = 7.1396 (5) A, Z = 4. The final residual after full-matrix least-squares refinement was R = 0.042 for 348 observed reflections. The ammonium ions are thermally disordered into two orientations, displaced by an angle of approximately 42 0 about an axis parallel to the c axis. (Auth.)

  11. Fixed switching frequency applied in single-phase boost AC to DC converter

    International Nuclear Information System (INIS)

    Chen, T.-C.; Ren, T.-J.; Ou, J.-C.

    2009-01-01

    The fixed switching frequency control for a single-phase boost AC to DC converter to achieve a sinusoidal line current and unity power factor is proposed in this paper. The relation between the line current error and the fixed switching frequency was developed. For a limit line current error, the minimum switching frequency for a boost AC to DC converter can be achieved. The proposed scheme was implemented using a 32-bit digital signal processor TMS320C32. Simulations and experimental results demonstrate the feasibility and fast dynamic response of the proposed control strategy.

  12. Environment-assisted error correction of single-qubit phase damping

    International Nuclear Information System (INIS)

    Trendelkamp-Schroer, Benjamin; Helm, Julius; Strunz, Walter T.

    2011-01-01

    Open quantum system dynamics of random unitary type may in principle be fully undone. Closely following the scheme of environment-assisted error correction proposed by Gregoratti and Werner [J. Mod. Opt. 50, 915 (2003)], we explicitly carry out all steps needed to invert a phase-damping error on a single qubit. Furthermore, we extend the scheme to a mixed-state environment. Surprisingly, we find cases for which the uncorrected state is closer to the desired state than any of the corrected ones.

  13. An empirical relationship for homogenization in single-phase binary alloy systems

    Science.gov (United States)

    Unnam, J.; Tenney, D. R.; Stein, B. A.

    1979-01-01

    A semiempirical formula is developed for describing the extent of interaction between constituents in single-phase binary alloy systems with planar, cylindrical, or spherical interfaces. The formula contains two parameters that are functions of mean concentration and interface geometry of the couple. The empirical solution is simple, easy to use, and does not involve sequential calculations, thereby allowing quick estimation of the extent of interactions without lengthy calculations. Results obtained with this formula are in good agreement with those from a finite-difference analysis.

  14. A Study on Energy Saving of Single Phase Induction Motor By Voltage Control

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Jong Moon [Pusan College of Information Technolgy, Pusan (Korea); Kim, Joon Hong [Dong Myong College, Pusan (Korea)

    2001-06-01

    This paper describes a simple effective method for energy saving of AC motors having a widely variable load. The proposed method is based on an optimal efficiency control which is operated by voltage-current pattern such as to maintain the maximum efficiency on the efficiency-output characteristics of the motor, TRIAC voltage control characteristics. The parameters of simplified voltage-current pattern can be determined approximately and reliably from the rated voltage and current of the motor. Experiments are focused on a single phase capacitor motor, the optimal energy saving are proved by proposed method. (author). 8 refs., 15 figs.

  15. Experimental investigations of single and two-phase flow in a heated rod bundle

    International Nuclear Information System (INIS)

    Barthel, Frank; Franz, Ronald; Hampel, Uwe; Technische Univ. Dresden

    2013-01-01

    An experimental facility for the study of boiling flows in a 3 x 3 rod bundle geometry was setup. The bundle resembles in essential geometrical parts the geometry in a pressurized water reactor fuel element. The facility is operated with a refrigerant fluid. Beside standard instrumentation for temperature, pressure and flow rate we employed particle image velocimetry for single phase flow studies, gamma ray densitometry for integral gas fraction measurement sand ultrafast X-ray tomography for the study of the void dynamics in the cross-section. Moreover extensive thermo-instrumentation allows axial rod surface temperature measurements for the central heated rod. First results will be discussed in this article. (orig.)

  16. Detection and characterization of single nanoparticles by interferometric phase modulated ellipsometry

    International Nuclear Information System (INIS)

    Barroso, F.; Bosch, S.; Tort, N.; Arteaga, O.; Sancho-Parramon, J.; Jover, E.; Bertran, E.; Canillas, A.

    2011-01-01

    We introduce a new measurement system called Nanopolar interferometer devoted to monitor and characterize single nanoparticles which is based on the interferometric phase modulated ellipsometry technique. The system collects the backscattered light by the particles in the solid angle subtended by a microscope objective and then analyses its frequency components. The results for the detection of 2 μm and 50 nm particles are explained in terms of a cross polarization effect of the polarization vectors when the beam converts from divergent to parallel in the microscope objective. This explanation is supported with the results of the optical modelling using the exact Mie theory for the light scattered by the particles.

  17. Power quality improvement of single-phase photovoltaic systems through a robust synchronization method

    DEFF Research Database (Denmark)

    Hadjidemetriou, Lenos; Kyriakides, Elias; Yang, Yongheng

    2014-01-01

    An increasing amount of single-phase photovoltaic (PV) systems on the distribution network requires more advanced synchronization methods in order to meet the grid codes with respect to power quality and fault ride through capability. The response of the synchronization technique selected...... is crucial for the performance of PV inverters. In this paper, a new synchronization method with good dynamics and accurate response under highly distorted voltage is proposed. This method uses a Multi-Harmonic Decoupling Cell (MHDC), which cancels out the oscillations on the synchronization signals due...

  18. DQ reference frame modeling and control of single-phase active power decoupling circuits

    DEFF Research Database (Denmark)

    Tang, Yi; Qin, Zian; Blaabjerg, Frede

    2015-01-01

    . This paper presents the dq synchronous reference frame modeling of single-phase power decoupling circuits and a complete model describing the dynamics of dc-link ripple voltage is presented. The proposed model is universal and valid for both inductive and capacitive decoupling circuits, and the input...... of decoupling circuits can be either dependent or independent of its front-end converters. Based on this model, a dq synchronous reference frame controller is designed which allows the decoupling circuit to operate in two different modes because of the circuit symmetry. Simulation and experimental results...... are presented to verify the effectiveness of the proposed modeling and control method....

  19. A New Synchronous Reference Frame-Based Method for Single-Phase Shunt Active Power Filters

    DEFF Research Database (Denmark)

    Monfared, Mohammad; Golestan, Saeed; Guerrero, Josep M.

    2013-01-01

    This paper deals with the design of a novel method in the synchronous reference frame (SRF) to extract the reference compensating current for single-phase shunt active power filters (APFs). Unlike previous works in the SRF, the proposed method has an innovative feature that it does not need...... the fictitious current signal. Frequency-independent operation, accurate reference current extraction and relatively fast transient response are other key features of the presented strategy. The effectiveness of the proposed method is investigated by means of detailed mathematical analysis. The results confirm...

  20. Control Method of Single-phase Inverter Based Grounding System in Distribution Networks

    DEFF Research Database (Denmark)

    Wang, Wen; Yan, L.; Zeng, X.

    2016-01-01

    of neutral-to-ground voltage is critical for the safety of distribution networks. An active grounding system based on single-phase inverter is proposed to achieve this objective. Relationship between output current of the system and neutral-to-ground voltage is derived to explain the principle of neutral......The asymmetry of the inherent distributed capacitances causes the rise of neutral-to-ground voltage in ungrounded system or high resistance grounded system. Overvoltage may occur in resonant grounded system if Petersen coil is resonant with the distributed capacitances. Thus, the restraint...

  1. Single Phase Current-Source Active Rectifier for Traction: Control System Design and Practical Problems

    Directory of Open Access Journals (Sweden)

    Jan Michalik

    2006-01-01

    Full Text Available This research has been motivated by industrial demand for single phase current-source active rectifier dedicated for reconstruction of older types of dc machine locomotives. This paper presents converters control structure design and simulations. The proposed converter control is based on the mathematical model and due to possible interaction with railway signaling and required low switching frequency employs synchronous PWM. The simulation results are verified by experimental tests performed on designed laboratory prototype of power of 7kVA

  2. Photoacoustic wave propagating from normal into superconductive phases in Pb single crystals

    OpenAIRE

    Iwanaga, Masanobu

    2005-01-01

    Photoacoustic (PA) wave has been examined in a superconductor of the first kind, Pb single crystal. The PA wave is induced by optical excitation of electronic state and propagates from normal into superconductive phases below T$_{\\rm C}$. It is clearly shown by wavelet analysis that the measured PA wave includes two different components. The high-frequency component is MHz-ultrasonic and the relative low-frequency one is induced by thermal wave. The latter is observed in a similar manner irre...

  3. Control of single-phase islanded PV/battery minigrids based on power-line signaling

    DEFF Research Database (Denmark)

    Quintana, Pablo; Guerrero, Josep M.; Dragicevic, Tomislav

    2014-01-01

    should be utilized as efficiently as possible. This paper proposes a coordinated control strategy based on power-line signaling (PLS), instead of common communications, for a single-phase minigrid in which each unit can operate in different operation modes taking into account the resource limitation...... types of renewable energy sources (RES) and energy storage systems (ESS). Specifically, the recharging process of secondary battery, the most prominent ESS, should be done in a specific manner to preserve its life-time, microgrid line voltage must be kept within the bounds and the energy offered by RES...

  4. Energy efficient power electronic controller for a capacitor-run single-phase induction motor

    International Nuclear Information System (INIS)

    Saravana Ilango, G.; Samidurai, K.; Roykumar, M.; Thanushkodi, K.

    2009-01-01

    At present the speed control of a capacitor-run single-phase induction motor is being achieved by using triac based voltage regulators. This paper proposes a new scheme; an electronic transformer acts as a voltage regulator. Performance comparison is made between these two schemes in this paper. It is found that the proposed scheme has superior operating and performance characteristics. Experimental results show that apart from improvement in performance with respect to power factor and total harmonic distortion an appreciable amount of energy saving is also obtained in the electronic transformer based scheme.

  5. Novel Position and Speed Estimator for PM Single Phase Brushless D.C. Motor Drives

    DEFF Research Database (Denmark)

    Lepure, Liviu I.; Andreescu, Gheorghe-Daniel; Iles, Doris

    2010-01-01

    A novel position and speed estimator for single phase permanent magnet brushless d.c. (PMBLDC) motor drives, based on flux integration and prior knowledge of ΨPM (θ) is proposed here and an adequate correction algorithm is adopted in order to increase the robustness to noise and to reduce...... the sensitivity to accuracy of flux linkage estimation. A speed and current close loop control is employed based on the Hall signal and the motor is controlled at different speeds in order to validate the proposed estimation algorithm with satisfying results. The position correction effect is analyzed...

  6. Measurement of the single and two phase flow using newly developed average bidirectional flow tube

    International Nuclear Information System (INIS)

    Yun, Byong Jo; Euh, Dong Jin; Kang, Kyung Ho; Song, Chul Hwa; Baek, Won Pil

    2005-01-01

    A new instrument, an average BDFT (Birectional Flow Tube), was proposed to measure the flow rate in single and two phase flows. Its working principle is similar to that of the pitot tube, wherein the dynamic pressure is measured. In an average BDFT, the pressure measured at the front of the flow tube is equal to the total pressure, while that measured at the rear tube is slightly less than the static pressure of the flow field due to the suction effect downstream. The proposed instrument was tested in air/water vertical and horizontal test sections with an inner diameter of 0.08m. The tests were performed primarily in single phase water and air flow conditions to obtain the amplification factor(k) of the flow tube in the vertical and horizontal test sections. Tests were also performed in air/water vertical two phase flow conditions in which the flow regimes were bubbly, slug, and churn turbulent flows. In order to calculate the phasic mass flow rates from the measured differential pressure, the Chexal dirft-flux correlation and a momentum exchange factor between the two phases were introduced. The test results show that the proposed instrument with a combination of the measured void fraction, Chexal drift-flux correlation, and Bosio and Malnes' momentum exchange model could predict the phasic mass flow rates within a 15% error. A new momentum exchange model was also proposed from the present data and its implementation provides a 5% improvement to the measured mass flow rate when compared to that with the Bosio and Malnes' model

  7. Pressure transient analysis in single and two-phase water by finite difference methods

    International Nuclear Information System (INIS)

    Berry, G.F.; Daley, J.G.

    1977-01-01

    An important consideration in the design of LMFBR steam generators is the possibility of leakage from a steam generator water tube. The ensuing sodium/water reaction will be largely controlled by the amount of water available at the leak site, thus analysis methods treating this event must have the capability of accurately modeling pressure transients through all states of water occurring in a steam generator, whether single or two-phase. The equation systems of the present model consist of the conservation equations together with an equation of state for one-dimensional homogeneous flow. These equations are then solved using finite difference techniques with phase considerations and non-equilibrium effects being treated through the equation of state. The basis for water property computation is Keenan's 'fundamental equation of state' which is applicable to single-phase water at pressures less than 1000 bars and temperatures less than 1300 0 C. This provides formulations allowing computation of any water property to any desired precision. Two-phase properties are constructed from values on the saturation line. The use of formulations permits the direct calculation of any thermodynamic property (or property derivative) to great precision while requiring very little computer storage, but does involve considerable computation time. For this reason an optional calculation scheme based on the method of 'transfinite interpolation' is included to give rapid computation in selected regions with decreased precision. The conservation equations were solved using the second order Lax-Wendroff scheme which includes wall friction, allows the formation of shocks and locally supersonic flow. Computational boundary conditions were found from a method-of-characteristics solution at the reservoir and receiver ends. The local characteristics were used to interpolate data from inside the pipe to the boundary

  8. Phase transitions of single polymer chains and of polymer solutions: insights from Monte Carlo simulations

    International Nuclear Information System (INIS)

    Binder, K; Paul, W; Strauch, T; Rampf, F; Ivanov, V; Luettmer-Strathmann, J

    2008-01-01

    The statistical mechanics of flexible and semiflexible macromolecules is distinct from that of small molecule systems, since the thermodynamic limit can also be approached when the number of (effective) monomers of a single chain (realizable by a polymer solution in the dilute limit) is approaching infinity. One can introduce effective attractive interactions into a simulation model for a single chain such that a swollen coil contracts when the temperature is reduced, until excluded volume interactions are effectively canceled by attractive forces, and the chain conformation becomes almost Gaussian at the theta point. This state corresponds to a tricritical point, as the renormalization group theory shows. Below the theta temperature a fluid globule is predicted (at nonzero concentration then phase separation between dilute and semidilute solutions occurs), while at still lower temperature a transition to a solid phase (crystal or glass) occurs. Monte Carlo simulations have shown, however, that the fluid globule phase may become suppressed, when the range of the effective attractive forces becomes too short, with the result that a direct (ultimately first-order) transition from the swollen coil to the solid occurs. This behavior is analogous to the behavior of colloidal particles with a very short range of attractive forces, where liquid-vapor-type phase separation may be suppressed. Analogous first-order transitions from swollen coils to dense rodlike or toroidal structures occur for semiflexible polymers. Finally, the modifications of the behavior discussed when the polymers are adsorbed at surfaces are also mentioned, and possible relations to wetting behavior of polymer solutions are addressed.

  9. Evaluation of single-walled carbon nanohorns as sorbent in dispersive micro solid-phase extraction

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Soto, Juan Manuel; Cardenas, Soledad [Department of Analytical Chemistry, Institute of Fine Chemistry and Nanochemistry, Marie Curie Building, Campus de Rabanales, University of Cordoba, 14071 Cordoba (Spain); Valcarcel, Miguel, E-mail: qa1meobj@uco.es [Department of Analytical Chemistry, Institute of Fine Chemistry and Nanochemistry, Marie Curie Building, Campus de Rabanales, University of Cordoba, 14071 Cordoba (Spain)

    2012-02-10

    Highlights: Black-Right-Pointing-Pointer The potential of single walled carbon nanohorns in dispersive solid phase microextraction has been evaluated. Black-Right-Pointing-Pointer The method was characterized for the extraction of PAHs from waters. Black-Right-Pointing-Pointer Single walled carbon nanohorns were better extractant than carbon nanotubes and carbon nanocones. Black-Right-Pointing-Pointer The limits of detection were adequate for the target analytes in environmental waters. - Abstract: A new dispersive micro solid-phase extraction method which uses single-walled carbon nanohorns (SWNHs) as sorbent is proposed. The procedure combines the excellent sorbent properties of the nanoparticles with the efficiency of the dispersion of the material in the sample matrix. Under these conditions, the interaction with the analytes is maximized. The determination of polycyclic aromatic hydrocarbons was selected as model analytical problem. Two dispersion strategies were evaluated, being the functionalization via microwave irradiation better than the use of a surfactant. The extraction was accomplished by adding 1 mL of oxidized SWHNs (o-SWNHs) dispersion to 10 mL of water sample. After extraction, the mixture was passed through a disposable Nylon filter were the nanoparticles enriched with the PAHs were retained. The elution was carried out with 100 {mu}L of hexane. The limits of detection achieved were between 30 and 60 ng L{sup -1} with a precision (as repeatability) better than 12.5%. The recoveries obtained for the analytes in three different water samples were acceptable in all instances. The performance of o-SWNHs was favourably compared with that provided by carboxylated single-walled carbon nanotubes and thermally treated carbon nanocones.

  10. Trellis coding with Continuous Phase Modulation (CPM) for satellite-based land-mobile communications

    Science.gov (United States)

    1989-01-01

    This volume of the final report summarizes the results of our studies on the satellite-based mobile communications project. It includes: a detailed analysis, design, and simulations of trellis coded, full/partial response CPM signals with/without interleaving over various Rician fading channels; analysis and simulation of computational cutoff rates for coherent, noncoherent, and differential detection of CPM signals; optimization of the complete transmission system; analysis and simulation of power spectrum of the CPM signals; design and development of a class of Doppler frequency shift estimators; design and development of a symbol timing recovery circuit; and breadboard implementation of the transmission system. Studies prove the suitability of the CPM system for mobile communications.

  11. Combined effects of potassium chloride and ethanol as mobile phase modulators on hydrophobic interaction and reversed-phase chromatography of three insulin variants.

    Science.gov (United States)

    Johansson, Karolina; Frederiksen, Søren S; Degerman, Marcus; Breil, Martin P; Mollerup, Jørgen M; Nilsson, Bernt

    2015-02-13

    The two main chromatographic modes based on hydrophobicity, hydrophobic interaction chromatography (HIC) and reversed-phase chromatography (RPC), are widely used for both analytical and preparative chromatography of proteins in the pharmaceutical industry. Despite the extensive application of these separation methods, and the vast amount of studies performed on HIC and RPC over the decades, the underlying phenomena remain elusive. As part of a systematic study of the influence of mobile phase modulators in hydrophobicity-based chromatography, we have investigated the effects of both KCl and ethanol on the retention of three insulin variants on two HIC adsorbents and two RPC adsorbents. The focus was on the linear adsorption range, separating the modulator effects from the capacity effects, but some complementary experiments at higher load were included to further investigate observed phenomena. The results show that the modulators have the same effect on the two RPC adsorbents in the linear range, indicating that the modulator concentration only affects the activity of the solute in the mobile phase, and not that of the solute-ligand complex, or that of the ligand. Unfortunately, the HIC adsorbents did not show the same behavior. However, the insulin variants displayed a strong tendency toward self-association on both HIC adsorbents; on one in particular. Since this causes peak fronting, the retention is affected, and this could probably explain the lack of congruity. This conclusion was supported by the results from the non-linear range experiments which were indicative of double-layer adsorption on the HIC adsorbents, while the RPC adsorbents gave the anticipated increased tailing at higher load. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Semiconducting tin and lead iodide perovskites with organic cations: phase transitions, high mobilities, and near-infrared photoluminescent properties.

    Science.gov (United States)

    Stoumpos, Constantinos C; Malliakas, Christos D; Kanatzidis, Mercouri G

    2013-08-05

    A broad organic-inorganic series of hybrid metal iodide perovskites with the general formulation AMI3, where A is the methylammonium (CH3NH3(+)) or formamidinium (HC(NH2)2(+)) cation and M is Sn (1 and 2) or Pb (3 and 4) are reported. The compounds have been prepared through a variety of synthetic approaches, and the nature of the resulting materials is discussed in terms of their thermal stability and optical and electronic properties. We find that the chemical and physical properties of these materials strongly depend on the preparation method. Single crystal X-ray diffraction analysis of 1-4 classifies the compounds in the perovskite structural family. Structural phase transitions were observed and investigated by temperature-dependent single crystal X-ray diffraction in the 100-400 K range. The charge transport properties of the materials are discussed in conjunction with diffuse reflectance studies in the mid-IR region that display characteristic absorption features. Temperature-dependent studies show a strong dependence of the resistivity as a function of the crystal structure. Optical absorption measurements indicate that 1-4 behave as direct-gap semiconductors with energy band gaps distributed in the range of 1.25-1.75 eV. The compounds exhibit an intense near-IR photoluminescence (PL) emission in the 700-1000 nm range (1.1-1.7 eV) at room temperature. We show that solid solutions between the Sn and Pb compounds are readily accessible throughout the composition range. The optical properties such as energy band gap, emission intensity, and wavelength can be readily controlled as we show for the isostructural series of solid solutions CH3NH3Sn(1-x)Pb(x)I3 (5). The charge transport type in these materials was characterized by Seebeck coefficient and Hall-effect measurements. The compounds behave as p- or n-type semiconductors depending on the preparation method. The samples with the lowest carrier concentration are prepared from solution and are n-type; p

  13. Safe routes to school (SRTS) statewide mobility assessment study : phase I report.

    Science.gov (United States)

    2010-01-01

    This report presents the results of phase one of a two phase study designed to support state-level management of the Federal Highway Administration Safe Routes to School (SRTS) program. The study aims to achieve three objectives: (1) identify and use...

  14. Ion Mobility Spectrometry-Mass Spectrometry Coupled with Gas-Phase Hydrogen/Deuterium Exchange for Metabolomics Analyses

    Science.gov (United States)

    Maleki, Hossein; Karanji, Ahmad K.; Majuta, Sandra; Maurer, Megan M.; Valentine, Stephen J.

    2018-02-01

    Ion mobility spectrometry-mass spectrometry (IMS-MS) in combination with gas-phase hydrogen/deuterium exchange (HDX) and collision-induced dissociation (CID) is evaluated as an analytical method for small-molecule standard and mixture characterization. Experiments show that compound ions exhibit unique HDX reactivities that can be used to distinguish different species. Additionally, it is shown that gas-phase HDX kinetics can be exploited to provide even further distinguishing capabilities by using different partial pressures of reagent gas. The relative HDX reactivity of a wide variety of molecules is discussed in light of the various molecular structures. Additionally, hydrogen accessibility scoring (HAS) and HDX kinetics modeling of candidate ( in silico) ion structures is utilized to estimate the relative ion conformer populations giving rise to specific HDX behavior. These data interpretation methods are discussed with a focus on developing predictive tools for HDX behavior. Finally, an example is provided in which ion mobility information is supplemented with HDX reactivity data to aid identification efforts of compounds in a metabolite extract.

  15. Effect of increasing proportions of lignocellulosic cosubstrate on the single-phase and two-phase digestion of readily biodegradable substrate

    International Nuclear Information System (INIS)

    Ganesh, Rangaraj; Torrijos, Michel; Sousbie, Philippe; Lugardon, Aurelien; Steyer, Jean Philippe; Delgenes, Jean Philippe

    2015-01-01

    The influence of different proportions of lignocellulosic substrate (cow manure with straw, CM) on the single-phase (conventional reactor) and two-phase (acidification/methanation with solids and liquid recirculation) digestion of a readily biodegradable substrate (fruit and vegetable waste, FVW) was investigated in order to determine the optimum cosubstrate ratio and the process best suited for codigestion. Both processes were fed initially with FVW, followed by FVW and CM at 80%:20% and 60%:40% (on volatile solids, VS basis) during an experiment run over eleven months. For the single-phase process, energy yield and VS destruction decreased by 11% and 9% with the 80%:20% FVW and CM ratio and by 16% and 17% with the 60%:40% feed ratio when compared to 100% FVW feed. For the two-phase process, energy yield and VS destruction decreased by 21% and 14% with 80%:20% feed ratio and by 48% and 33% with 60%:40% feed ratio compared to 100% FVW. Substrate solubilization in the acidification reactor was very efficient for all the feed proportions but it resulted in compounds other than volatile fatty acid (non-VFA COD) which were not easily amenable to methane generation. This led to a lower energy yield per kg of VS fed in the two-phase process compared to the single-phase process for the respective waste combination. For single-phase digestion, both 80%:20% and 60%:40% ratios were effective co-substrate combinations due to their higher energy yield. The two-phase process can be used for these ratios if higher VS reduction and a higher loading rate are the objectives. - Highlights: • Effect of cow manure addition on the digestion of fruit and vegetable waste studied. • Single and two-phase processes were compared for three different waste ratios. • Methane and energy yields were higher by single-phase than the two-phase process. • FVW-Cow manure ratios of 80%:20% and 60%:40% found effective for single-phase digestion. • Two-phase process resulted in higher solids

  16. Electron attachment to DNA single strands: gas phase and aqueous solution.

    Science.gov (United States)

    Gu, Jiande; Xie, Yaoming; Schaefer, Henry F

    2007-01-01

    The 2'-deoxyguanosine-3',5'-diphosphate, 2'-deoxyadenosine-3',5'-diphosphate, 2'-deoxycytidine-3',5'-diphosphate and 2'-deoxythymidine-3',5'-diphosphate systems are the smallest units of a DNA single strand. Exploring these comprehensive subunits with reliable density functional methods enables one to approach reasonable predictions of the properties of DNA single strands. With these models, DNA single strands are found to have a strong tendency to capture low-energy electrons. The vertical attachment energies (VEAs) predicted for 3',5'-dTDP (0.17 eV) and 3',5'-dGDP (0.14 eV) indicate that both the thymine-rich and the guanine-rich DNA single strands have the ability to capture electrons. The adiabatic electron affinities (AEAs) of the nucleotides considered here range from 0.22 to 0.52 eV and follow the order 3',5'-dTDP > 3',5'-dCDP > 3',5'-dGDP > 3',5'-dADP. A substantial increase in the AEA is observed compared to that of the corresponding nucleic acid bases and the corresponding nucleosides. Furthermore, aqueous solution simulations dramatically increase the electron attracting properties of the DNA single strands. The present investigation illustrates that in the gas phase, the excess electron is situated both on the nucleobase and on the phosphate moiety for DNA single strands. However, the distribution of the extra negative charge is uneven. The attached electron favors the base moiety for the pyrimidine, while it prefers the 3'-phosphate subunit for the purine DNA single strands. In contrast, the attached electron is tightly bound to the base fragment for the cytidine, thymidine and adenosine nucleotides, while it almost exclusively resides in the vicinity of the 3'-phosphate group for the guanosine nucleotides due to the solvent effects. The comparatively low vertical detachment energies (VDEs) predicted for 3',5'-dADP(-) (0.26 eV) and 3',5'-dGDP(-) (0.32 eV) indicate that electron detachment might compete with reactions having high activation barriers

  17. Characterisation of different single and multilayer films using phase modulated spectroscopic ellipsometry

    International Nuclear Information System (INIS)

    Das, N.C.; Bhattacharyya, D.; Thakur, S.

    1998-06-01

    Different single layers and multilayer coatings deposited by e-beam evaporation and r.f. sputtering techniques have been characterised by the Phase Modulated Spectroscopic Ellipsometer, installed recently in the Spectroscopy Division, B.A.R.C. The Phase Modulated technique provides a faster and more accurate data acquisition process than the conventional ellipsometry. Measurements have been done on single layers of Cu, Si and ZrO 2 films and on multilayer thin films devices e.g., high reflectivity mirror, beam combiner, beam splitter, narrow band filter etc. consisting of several bilayers of TiO 2 /SiO 2 . The measured Ellipsometry spectra is then fitted with a theoretical spectra generated assuming an appropriate model regarding the sample. The layer thickness and composition have been used as fitting parameters. The optical constants of the substrates have been supplied and a trial dispersion relation have been used for the layers. In case of inhomogeneous layers, trial compositions have been given for the individual components for each layer. The roughness of the layers has been taken into account by assuming the film to be an inhomogeneous mixture of material and voids. The fittings have been done objectively by minimising the squared difference (χ 2 ) between the measured and calculated values of the ellipsometric parameters and thus accurate information have been derived regarding the thickness and optical constants (viz, the refractive index and extinction coefficient) of the different layers, the surface roughness and the inhomogeneities present in the layers. (author)

  18. Common-Ground-Type Transformerless Inverters for Single-Phase Solar Photovoltaic Systems

    DEFF Research Database (Denmark)

    Siwakoti, Yam Prasad; Blaabjerg, Frede

    2018-01-01

    This paper proposes a family of novel flying capacitor transformerless inverters for single-phase photovoltaic (PV) systems. Each of the new topologies proposed is based on a flying capacitor principle and requires only four power switches and/or diodes, one capacitor, and a small filter at the o......This paper proposes a family of novel flying capacitor transformerless inverters for single-phase photovoltaic (PV) systems. Each of the new topologies proposed is based on a flying capacitor principle and requires only four power switches and/or diodes, one capacitor, and a small filter...... at the output stage. A simple unipolar sinusoidal pulse width modulation technique is used to modulate the inverter to minimize the switching loss, output current ripple, and the filter requirements. In general, the main advantages of the new inverter topologies are: 1) the negative polarity of the PV...... description of the operating principle with modulation techniques, design guidelines, and comprehensive comparisons is presented to reveal the properties and limitations of each topology in detail. Finally, experimental results of 1-kVA prototypes are presented to prove the concept and theoretical analysis...

  19. A Standalone Solar Photovoltaic Power Generation using Cuk Converter and Single Phase Inverter

    Science.gov (United States)

    Verma, A. K.; Singh, B.; Kaushika, S. C.

    2013-03-01

    In this paper, a standalone solar photovoltaic (SPV) power generating system is designed and modeled using a Cuk dc-dc converter and a single phase voltage source inverter (VSI). In this system, a dc-dc boost converter boosts a low voltage of a PV array to charge a battery at 24 V using a maximum power point tracking control algorithm. To step up a 24 V battery voltage to 360 V dc, a high frequency transformer based isolated dc-dc Cuk converter is used to reduce size, weight and losses. The dc voltage of 360 V is fed to a single phase VSI with unipolar switching to achieve a 230 Vrms, 50 Hz ac. The main objectives of this investigation are on efficiency improvement, reduction in cost, weight and size of the system and to provide an uninterruptible power to remotely located consumers. The complete SPV system is designed and it is modeled in MATLAB/Simulink. The simulated results are presented to demonstrate its satisfactory performance for validating the proposed design and control algorithm.

  20. Fabrication and Characterization of Single Phase α-Alumina Membranes with Tunable Pore Diameters

    Science.gov (United States)

    Masuda, Tatsuya; Asoh, Hidetaka; Haraguchi, Satoshi; Ono, Sachiko

    2015-01-01

    Nanoporous and single phase α-alumina membranes with pore diameters tunable over a wide range of approximately 60–350 nm were successfully fabricated by optimizing the conditions for anodizing, subsequent detachment, and heat treatment. The pore diameter increased and the cell diameter shrunk upon crystallization to α-alumina by approximately 20% and 3%, respectively, in accordance with the 23% volume shrinkage resulting from the change in density associated with the transformation from the amorphous state to α-alumina. Nevertheless, flat α-alumina membranes, each with a diameter of 25 mm and a thickness of 50 μm, were obtained without thermal deformation. The α-alumina membranes exhibited high chemical resistance in various concentrated acidic and alkaline solutions as well as when exposed to high temperature steam under pressure. The Young’s modulus and hardness of the single phase α-alumina membranes formed by heat treatment at 1250 °C were notably decreased compared to the corresponding amorphous membranes, presumably because of the nodular crystallite structure of the cell walls and the substantial increase in porosity. Furthermore, when used for filtration, the α-alumina membrane exhibited a level of flux higher than that of the commercial ceramic membrane. PMID:28788005

  1. Fabrication and Characterization of Single Phase α-Alumina Membranes with Tunable Pore Diameters

    Directory of Open Access Journals (Sweden)

    Tatsuya Masuda

    2015-03-01

    Full Text Available Nanoporous and single phase α-alumina membranes with pore diameters tunable over a wide range of approximately 60–350 nm were successfully fabricated by optimizing the conditions for anodizing, subsequent detachment, and heat treatment. The pore diameter increased and the cell diameter shrunk upon crystallization to α-alumina by approximately 20% and 3%, respectively, in accordance with the 23% volume shrinkage resulting from the change in density associated with the transformation from the amorphous state to α-alumina. Nevertheless, flat α-alumina membranes, each with a diameter of 25 mm and a thickness of 50 μm, were obtained without thermal deformation. The α-alumina membranes exhibited high chemical resistance in various concentrated acidic and alkaline solutions as well as when exposed to high temperature steam under pressure. The Young’s modulus and hardness of the single phase α-alumina membranes formed by heat treatment at 1250 °C were notably decreased compared to the corresponding amorphous membranes, presumably because of the nodular crystallite structure of the cell walls and the substantial increase in porosity. Furthermore, when used for filtration, the α-alumina membrane exhibited a level of flux higher than that of the commercial ceramic membrane.

  2. A note on similarity in single-phase and porous-medium natural convection

    International Nuclear Information System (INIS)

    Lyall, H.G.

    1981-03-01

    The similarity laws for single-phase and porous-medium natural convection are developed. For single-phase flow Nu = Nu(Ra) implies that inertial effects are negligible, while Nu = Nu(Ra.Pr) implies that viscous effects are. The first correlation is adequate for Pr>10, while the second applies for Pr<0.01. For intermediate values of Pr, a more general correlation, Nu = Nu(Ra,Pr) is necessary. For a porous-medium, if inertial effects and dispersion are negligible, Nu* = Nu*(Ra*). However dispersion will only be negligible if the ratio of grain size d to the width of the region L is very small (d/L<< l). If this condition does not hold it is necessary to model d/L. If inertial effects are significant, i.e. the Reynolds number is too large for Darcy's law to apply, a group containing the effective Prandtl number, Pr*, also needs to be modelled for similarity. (author)

  3. Simplified thermal-hydraulic analysis of single phase natural circulation circuit with two heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, Larissa Cunha; Su, Jian, E-mail: larissa@lasme.coppe.ufrj.br, E-mail: sujian@lasme.coppe.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenhraria Nuclear; Cotta, Renato Machado, E-mail: cotta@mecanica.coppe.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (POLI/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Mecanica

    2015-07-01

    Single phase natural circulation circuits composed of two convective heat exchangers and connecting tubes are important for the passive heat removal from spent fuel pools (SFP). To keep the structural integrity of the stored spent fuel assemblies, continuously cooling has to be provided in order to avoid increase at the pool temperature and subsequent uncovering of the fuel and enhanced reaction between water and metal releasing hydrogen. Decay heat can achieve considerably high amounts of energy e.g. in the AP1000, considering the emergency fuel assemblies, the maximum heat decay will reach 13 MW in the 15th day (Westinghouse Electric Company, 2010). A highly efficient alternative to do so is by means of natural circulation, which is cost-effective compared to active cooling systems and is inherently safer since presents less associated devices and no external work is required. Many researchers have investigated safety and stability aspects of natural circulation loops (NCL). However, there is a lack of literature concerning the improvement of NCL through a standard unified methodology, especially for natural circulation circuits with two heat exchangers. In the present study, a simplified thermal-hydraulic analysis of single phase natural circulation circuit with two heat exchanges is presented. Relevant dimensionless key groups were proposed to for the design and safety analysis of a scaled NCL for the cooling of spent fuel storage pool with convective cooling and heating. (author)

  4. Experimental studies in a single-phase parallel channel natural circulation system. Preliminary results

    International Nuclear Information System (INIS)

    Bodkha, Kapil; Pilkhwal, D.S.; Jana, S.S.; Vijayan, P.K.

    2016-01-01

    Natural circulation systems find extensive applications in industrial engineering systems. One of the applications is in nuclear reactor where the decay heat is removed by natural circulation of the fluid under off-normal conditions. The upcoming reactor designs make use of natural circulation in order to remove the heat from core under normal operating conditions also. These reactors employ multiple vertical fuel channels with provision of on-power refueling/defueling. Natural circulation systems are relatively simple, safe and reliable when compared to forced circulation systems. However, natural circulation systems are prone to encounter flow instabilities which are highly undesirable for various reasons. Presence of parallel channels under natural circulation makes the system more complicated. To examine the behavior of parallel channel system, studies were carried out for single-phase natural circulation flow in a multiple vertical channel system. The objective of the present work is to study the flow behavior of the parallel heated channel system under natural circulation for different operating conditions. Steady state and transient studies have been carried out in a parallel channel natural circulation system with three heated channels. The paper brings out the details of the system considered, different cases analyzed and preliminary results of studies carried out on a single-phase parallel channel system.

  5. Experimental study of single-phase pressure drops in coarse particle beds

    Energy Technology Data Exchange (ETDEWEB)

    Clavier, R., E-mail: remi.clavier@irsn.fr [IRSN Cadarache, Saint Paul-lez-Durance (France); Chikhi, N., E-mail: nourdine.chikhi@irsn.fr [IRSN Cadarache, Saint Paul-lez-Durance (France); Fichot, F., E-mail: florian.fichot@irsn.fr [IRSN Cadarache, Saint Paul-lez-Durance (France); Quintard, M., E-mail: Michel.Quintard@imft.fr [Université de Toulouse, Allée Camille Soula, F-31400 Toulouse (France); INPT, UPS, Allée Camille Soula, F-31400 Toulouse (France); IMFT (Institut de Mécanique des Fluides de Toulouse), Allée Camille Soula, F-31400 Toulouse (France); CNRS, F-31400 Toulouse (France)

    2017-02-15

    Motivated by uncertainty reduction in nuclear debris beds coolability, experiments have been conducted on the CALIDE facility in order to investigate single-phase pressure losses in representative debris beds, i.e., high sphericity (>80%) particle beds with small size dispersion (from 1 mm to 10 mm), for which no validated model exists. In this paper, experimental results are presented and analyzed in order to identify a simple correlation for single-phase flow pressure losses generated in this kind of porous media in reflooding flowing conditions, which cover Darcy to weakly turbulent regimes. In the literature, it has been observed that their behavior can be accurately described by a Darcy–Forchheimer law, involving the sum of a linear term and a quadratic non-linear deviation, with respect to the filtration velocity. Expressions for the coefficients of the linear and quadratic terms are determined by assessing the possibility to evaluate equivalent diameters, i.e., characteristic lengths allowing correct predictions of the linear and quadratic terms by the Ergun equation. It has been observed that the Sauter diameter of particles allows a very precise prediction of the linear term, while the quadratic term can be predicted using the product of the Sauter diameter and a sphericity coefficient as an equivalent diameter.

  6. Predicting muscle forces during the propulsion phase of single leg triple hop test.

    Science.gov (United States)

    Alvim, Felipe Costa; Lucareli, Paulo Roberto Garcia; Menegaldo, Luciano Luporini

    2018-01-01

    Functional biomechanical tests allow the assessment of musculoskeletal system impairments in a simple way. Muscle force synergies associated with movement can provide additional information for diagnosis. However, such forces cannot be directly measured noninvasively. This study aims to estimate muscle activations and forces exerted during the preparation phase of the single leg triple hop test. Two different approaches were tested: static optimization (SO) and computed muscle control (CMC). As an indirect validation, model-estimated muscle activations were compared with surface electromyography (EMG) of selected hip and thigh muscles. Ten physically healthy active women performed a series of jumps, and ground reaction forces, kinematics and EMG data were recorded. An existing OpenSim model with 92 musculotendon actuators was used to estimate muscle forces. Reflective markers data were processed using the OpenSim Inverse Kinematics tool. Residual Reduction Algorithm (RRA) was applied recursively before running the SO and CMC. For both, the same adjusted kinematics were used as inputs. Both approaches presented similar residuals amplitudes. SO showed a closer agreement between the estimated activations and the EMGs of some muscles. Due to inherent EMG methodological limitations, the superiority of SO in relation to CMC can be only hypothesized. It should be confirmed by conducting further studies comparing joint contact forces. The workflow presented in this study can be used to estimate muscle forces during the preparation phase of the single leg triple hop test and allows investigating muscle activation and coordination. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. MDCT of acute pancreatitis: Intraindividual comparison of single-phase versus dual-phase MDCT for initial assessment of acute pancreatitis using different CT scoring systems

    Energy Technology Data Exchange (ETDEWEB)

    Avanesov, Maxim, E-mail: m.avanesov@uke.de [Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg (Germany); Weinrich, Julius M.; Kraus, Thomas [Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg (Germany); Derlin, Thorsten [Department of Nuclear Medicine, Hannover Medical School (Germany); Adam, Gerhard; Yamamura, Jin [Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg (Germany); Karul, Murat [Department of Diagnostic and Interventional Radiology, Marienkrankenhaus Hamburg (Germany)

    2016-11-15

    Objectives: The purpose of the retrospective study was to evaluate the additional value of dual-phase multidetector computed tomography (MDCT) protocols over a single-phase protocol on initial MDCT in patients with acute pancreatitis using three CT-based pancreatitis severity scores with regard to radiation dose. Methods: In this retrospective, IRB approved study MDCT was performed in 102 consecutive patients (73 males; 55years, IQR48–64) with acute pancreatitis. Inclusion criteria were CT findings of interstitial edematous pancreatitis (IP) or necrotizing pancreatitis (NP) and a contrast-enhanced dual-phase (arterial phase and portal-venous phase) abdominal CT performed at ≥72 h after onset of symptoms. The severity of pancreatic and extrapancreatic changes was independently assessed by 2 observers using 3 validated CT-based scoring systems (CTSI, mCTSI, EPIC). All scores were applied to arterial phase and portal venous phase scans and compared to score results of portal venous phase scans, assessed ≥14 days after initial evaluation. For effective dose estimation, volume CT dose index (CTDIvol) and dose length product (DLP) were recorded in all examinations. Results: In neither of the CT severity scores a significant difference was observed after application of a dual-phase protocol compared with a single-phase protocol (IP: CTSI: 2.7 vs. 2.5, p = 0.25; mCTSI: 4.0 vs. 4.0, p = 0.10; EPIC: 2.0 vs. 2.0, p = 0.41; NP: CTSI: 8.0 vs. 7.0, p = 0.64; mCTSI: 8.0 vs. 8.0, p = 0.10; EPIC: 3.0 vs. 3.0, p = 0.06). The application of a single-phase CT protocol was associated with a median effective dose reduction of 36% (mean dose reduction 31%) compared to a dual-phase CT scan. Conclusions: An initial dual-phase abdominal CT after ≥72 h after onset of symptoms of acute pancreatitis was not superior to a single-phase protocol for evaluation of the severity of pancreatic and extrapancreatic changes. However, the effective radiation dose may be reduced by 36% using a

  8. Phase-coexistence simulations of fluid mixtures by the Markov Chain Monte Carlo method using single-particle models

    KAUST Repository

    Li, Jun; Calo, Victor M.

    2013-01-01

    models although its deviation in the liquid phase is greater. Since the single-particle model reduces the particle number and avoids the time-consuming Ewald summation used to evaluate Coulomb interactions, the proposed model improves the computational

  9. Single Crystal Piezoelectric Stack Actuator DM with Integrated Low-Power HVA-Based Driver ASIC, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I project aims to develop an innovative batch fabrication technique to create single crystal PMN-PT stack actuator deformable mirrors (DM) at low...

  10. Mobilities Mobilities

    Directory of Open Access Journals (Sweden)

    César Pompeyo

    2011-12-01

    Full Text Available Urry, John (2007 Mobilities.Oxford: Polity Press.Urry, John (2007 Mobilities.Oxford: Polity Press.John Urry (1946-, profesor en la Universidad de Lancaster, es un sociólogo de sobra conocido y altamente reputado en el panorama internacional de las ciencias sociales. Su dilatada carrera, aparentemente dispersa y diversificada, ha seguido senderos bastante bien definidos dejando tras de sí un catálogo extenso de obras sociológicas de primer nivel. Sus primeros trabajos se centraban en el campo de la teoría social y la filosofía de las ciencias sociales o de la sociología del poder [...

  11. Comparative performance and microbial community of single-phase and two-phase anaerobic systems co-digesting cassava pulp and pig manure

    DEFF Research Database (Denmark)

    Panichnumsin, P.; Ahring, B.K.; Nopharatana, A.

    2010-01-01

    In this study, we illustrated the performance and microbial community of single- and two-phase systems anaerobically co-digesting cassava pulp and pig manure. The results showed that the volatile solid reduction and biogas productivity of two-phase CSTR were 66 ± 4% and 2000 ± 210 ml l-1 d-1, while...... those of singlephase CSTR were 59 ± 1% and 1670 ± 60 ml l-1 d-1, respectively. Codigestion in two-phase CSTR gave higher 12% solid degradation and 25% methane production than single-phase CSTR. Phylogenetic analysis of 16S rDNA clone library revealed that the Bacteroidetes were the most abundant group......, followed by the Clostridia in singlephase CSTR. In hydrolysis/acidification reactor of two-phase system, the bacteria within the phylum Firmicutes, especially Clostridium, Eubacteriaceae and Lactobacillus were the dominant phylogenetic groups. Among the Archaea, Methanosaeta sp. was the exclusive...

  12. On the use of nuclear magnetic resonance to measure velocity and its fluctuations in single-phase and two-phase flows

    International Nuclear Information System (INIS)

    Jullien, Pierre

    2013-01-01

    This work deals with the use of NMR to measure velocity and its fluctuations in single-phase and two-phase flows. PGSE and imaging sequences have been used to determine the velocity distributions in upward turbulent pipe flows. NMR signals have been analysed in detail and the main artifacts have been characterized and suppressed. The measuring technique has been validated by comparison with a reference published data. A first comparison to 'homemade' hot-wire results in single-phase flow of water is presented and is very promising. Preliminary NMR results in two-phase flows emphasize the interest of NMR to benchmark velocity measurements in two-phase flows. Prospects of research have been identified, which will pave the way for the sequel of this research. (author) [fr

  13. Low Voltage Ride-Through Capability of a Single-Stage Single-Phase Photovoltaic System Connected to the Low-Voltage Grid

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede

    2013-01-01

    The progressively growing of single-phase photovoltaic (PV) systems makes the Distribution System Operators (DSO) to update or revise the existing grid codes in order to guarantee the availability, quality and reliability of the electrical system. It is expected that the future PV systems connected...... to the low-voltage grid will be more active with functionalities of low voltage ride-through (LVRT) and the grid support capability, which is not the case today. In this paper, the operation principle is demonstrated for a single-phase grid-connected PV system in low voltage ride through operation in order...... to map future challenges. The system is verified by simulations and experiments. Test results show that the proposed power control method is effective and the single-phase PV inverters connected to low-voltage networks are ready to provide grid support and ride-through voltage fault capability...

  14. An Ultrathin Single Crystalline Relaxor Ferroelectric Integrated on a High Mobility Semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Moghadam, Reza M. [Department; Xiao, Zhiyong [Department; Ahmadi-Majlan, Kamyar [Department; Grimley, Everett D. [Department; Bowden, Mark [Environmental; amp, Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Ong, Phuong-Vu [Physical; amp, Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Chambers, Scott A. [Physical; amp, Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Lebeau, James M. [Department; Hong, Xia [Department; Sushko, Peter V. [Physical; amp, Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Ngai, Joseph H. [Department

    2017-09-13

    The epitaxial growth of multifunctional oxides on semiconductors has opened a pathway to introduce new functionalities to semiconductor device technologies. In particular, ferroelectric materials integrated on semiconductors could lead to low-power field-effect devices that can be used for logic or memory. Essential to realizing such field-effect devices is the development of ferroelectric metal-oxide-semiconductor (MOS) capacitors, in which the polarization of a ferroelectric gate is coupled to the surface potential of a semiconducting channel. Here we demonstrate that ferroelectric MOS capacitors can be realized using single crystalline SrZrxTi1-xO3 (x= 0.7) that has been epitaxially grown on Ge. We find that the ferroelectric properties of SrZrxTi1-xO3 are exceptionally robust, as gate layers as thin as 5 nm give rise to hysteretic capacitance-voltage characteristics that are 2 V in width. The development of ferroelectric MOS capacitors with gate thicknesses that are technologically relevant opens a pathway to realize scalable ferroelectric field-effect devices.

  15. Ionic liquid as a mobile phase additive in high-performance liquid chromatography for the simultaneous determination of eleven fluorescent whitening agents in paper materials.

    Science.gov (United States)

    Wang, Qing; Chen, Xianbo; Qiu, Bin; Zhou, Liang; Zhang, Hui; Xie, Juan; Luo, Yan; Wang, Bin

    2016-04-01

    In the present study, 11 4,4'-diaminostilbene-2,2'-disulfonic acid based fluorescent whitening agents with different numbers of sulfonic acid groups were separated by using an ionic liquid as a mobile phase additive in high-performance liquid chromatography with fluorescence detection. The effects of ionic liquid concentration, pH of mobile phase B, and composition of mobile phase A on the separation of fluorescent whitening agents were systematically investigated. The ionic liquid tetrabutylammonium tetrafluoroborate is superior to tetrabutylammomnium bromide for the separation of the fluorescent whitening agents. The optimal separation conditions were an ionic liquid concentration at 8 mM and the pH of mobile phase B at 8.5 with methanol as mobile phase A. The established method exhibited low limits of detection (0.04-0.07 ng/mL) and wide linearity ranges (0.30-20 ng/mL) with high linear correlation coefficients from 0.9994 to 0.9998. The optimized procedure was applied to analyze target analytes in paper samples with satisfactory results. Eleven target analytes were quantified, and the recoveries of spiked paper samples were in the range of 85-105% with the relative standard deviations from 2.1 to 5.1%. The obtained results indicated that the method was efficient for detection of 11 fluorescent whitening agents. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. An accurate mobility model for the I-V characteristics of n-channel enhancement-mode MOSFETs with single-channel boron implantation

    International Nuclear Information System (INIS)

    Chingyuan Wu; Yeongwen Daih

    1985-01-01

    In this paper an analytical mobility model is developed for the I-V characteristics of n-channel enhancement-mode MOSFETs, in which the effects of the two-dimensional electric fields in the surface inversion channel and the parasitic resistances due to contact and interconnection are included. Most importantly, the developed mobility model easily takes the device structure and process into consideration. In order to demonstrate the capabilities of the developed model, the structure- and process-oriented parameters in the present mobility model are calculated explicitly for an n-channel enhancement-mode MOSFET with single-channel boron implantation. Moreover, n-channel MOSFETs with different channel lengths fabricated in a production line by using a set of test keys have been characterized and the measured mobilities have been compared to the model. Excellent agreement has been obtained for all ranges of the fabricated channel lengths, which strongly support the accuracy of the model. (author)

  17. Reconfigurable Transmission Line for a Series-Fed Ku-Band Phased Array Using a Single Feed

    Science.gov (United States)

    Host, Nicholas K.; Chen, Chi-Chih; Volakis, John L.; Miranda. Felix, A.

    2013-01-01

    The paper presents a novel approach to realize a lowcost phased array using a simple feeding mechanism. Specifically, a single coplanar stripline (CPS) transmission line is used to feed the antenna array elements. By controlling the CPS's dielectric properties using a movable dielectric plunger, scanning is achieved. Due to its simplicity, single feed, and no phase shifters, this approach leads to a dramatic reduction in cost which does not scale for larger arrays.

  18. Numerical design of in-line X-ray phase-contrast imaging based on ellipsoidal single-bounce monocapillary

    International Nuclear Information System (INIS)

    Sun, Weiyuan; Liu, Zhiguo; Sun, Tianxi; Peng, Song; Ma, Yongzhong; Ding, Xunliang

    2014-01-01

    A new device using an ellipsoidal single-bounce monocapillary X-ray optics was numerically designed to realize in-line X-ray phase-contrast imaging by using conventional laboratory X-ray source with a large spot. Numerical simulation results validated the effectiveness of the proposed device and approach. The ellipsoidal single-bounce monocapillary X-ray optics had potential applications in the in-line phase contrast imaging with polychromatic X-rays

  19. Numerical design of in-line X-ray phase-contrast imaging based on ellipsoidal single-bounce monocapillary

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Weiyuan; Liu, Zhiguo [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Sun, Tianxi, E-mail: stx@bnu.edu.cn [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Peng, Song [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Ma, Yongzhong [Center for Disease Control and Prevention of Beijing, Beijing 100013 (China); Ding, Xunliang [The Key Laboratory of Beam Technology and Materials Modification of the Ministry of Education, Beijing Normal University, Beijing 100875 (China); College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2014-05-11

    A new device using an ellipsoidal single-bounce monocapillary X-ray optics was numerically designed to realize in-line X-ray phase-contrast imaging by using conventional laboratory X-ray source with a large spot. Numerical simulation results validated the effectiveness of the proposed device and approach. The ellipsoidal single-bounce monocapillary X-ray optics had potential applications in the in-line phase contrast imaging with polychromatic X-rays.

  20. Multi-scale Modeling of Compressible Single-phase Flow in Porous Media using Molecular Simulation

    KAUST Repository

    Saad, Ahmed Mohamed

    2016-05-01

    In this study, an efficient coupling between Monte Carlo (MC) molecular simulation and Darcy-scale flow in porous media is presented. The cell-centered finite difference method with a non-uniform rectangular mesh were used to discretize the simulation domain and solve the governing equations. To speed up the MC simulations, we implemented a recently developed scheme that quickly generates MC Markov chains out of pre-computed ones, based on the reweighting and reconstruction algorithm. This method astonishingly reduces the required computational time by MC simulations from hours to seconds. In addition, the reweighting and reconstruction scheme, which was originally designed to work with the LJ potential model, is extended to work with a potential model that accounts for the molecular quadrupole moment of fluids with non-spherical molecules such as CO2. The potential model was used to simulate the thermodynamic equilibrium properties for single-phase and two-phase systems using the canonical ensemble and the Gibbs ensemble, respectively. Comparing the simulation results with the experimental data showed that the implemented model has an excellent fit outperforming the standard LJ model. To demonstrate the strength of the proposed coupling in terms of computational time efficiency and numerical accuracy in fluid properties, various numerical experiments covering different compressible single-phase flow scenarios were conducted. The novelty in the introduced scheme is in allowing an efficient coupling of the molecular scale and Darcy scale in reservoir simulators. This leads to an accurate description of the thermodynamic behavior of the simulated reservoir fluids; consequently enhancing the confidence in the flow predictions in porous media.