WorldWideScience

Sample records for single mobile phase

  1. 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...... structures and properties have been proposed in the literature. The main aim of this paper is to provide a review of these PLLs. To this end, the single-phase PLLs are first classified into two major categories: 1) power-based PLLs (pPLLs), and 2) quadrature signal generation-based PLLs (QSG......-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....

  2. CsSnI3: Semiconductor or metal? High electrical conductivity and strong near-infrared photoluminescence from a single material. High hole mobility and phase-transitions.

    Science.gov (United States)

    Chung, In; Song, Jung-Hwan; Im, Jino; Androulakis, John; Malliakas, Christos D; Li, Hao; Freeman, Arthur J; Kenney, John T; Kanatzidis, Mercouri G

    2012-05-23

    CsSnI(3) is an unusual perovskite that undergoes complex displacive and reconstructive phase transitions and exhibits near-infrared emission at room temperature. Experimental and theoretical studies of CsSnI(3) have been limited by the lack of detailed crystal structure characterization and chemical instability. Here we describe the synthesis of pure polymorphic crystals, the preparation of large crack-/bubble-free ingots, the refined single-crystal structures, and temperature-dependent charge transport and optical properties of CsSnI(3), coupled with ab initio first-principles density functional theory (DFT) calculations. In situ temperature-dependent single-crystal and synchrotron powder X-ray diffraction studies reveal the origin of polymorphous phase transitions of CsSnI(3). The black orthorhombic form of CsSnI(3) demonstrates one of the largest volumetric thermal expansion coefficients for inorganic solids. Electrical conductivity, Hall effect, and thermopower measurements on it show p-type metallic behavior with low carrier density, despite the optical band gap of 1.3 eV. Hall effect measurements of the black orthorhombic perovskite phase of CsSnI(3) indicate that it is a p-type direct band gap semiconductor with carrier concentration at room temperature of ∼ 10(17) cm(-3) and a hole mobility of ∼585 cm(2) V(-1) s(-1). The hole mobility is one of the highest observed among p-type semiconductors with comparable band gaps. Its powders exhibit a strong room-temperature near-IR emission spectrum at 950 nm. Remarkably, the values of the electrical conductivity and photoluminescence intensity increase with heat treatment. The DFT calculations show that the screened-exchange local density approximation-derived band gap agrees well with the experimentally measured band gap. Calculations of the formation energy of defects strongly suggest that the electrical and light emission properties possibly result from Sn defects in the crystal structure, which arise

  3. Single-phase to three-phase power conversion interface

    Science.gov (United States)

    Wu, Jinn-Chang; Wang, Yung-Shan; Jou, Hurng-Liahng; Lu, Wei-Tso

    2016-07-01

    This study proposes a single-phase to three-phase power conversion interface which converts the power from a single-phase utility to three-phase power for a three-phase load. The proposed single-phase to three-phase power conversion interface comprises a bridge-type switch set, a set of three-phase inductors, a transformer set and a set of three-phase capacitors. A current-mode control controls the switching of bridge-type switch set, to generate a set of nonzero-sequence (NZS) currents and a set of zero-sequence (ZS) currents. The transformer set is used to decouple the NZS currents and the ZS currents. The NZS currents are used to generate a high-quality three-phase voltage that supplies power to a three-phase load. The ZS currents flow to the single-phase utility so that the utility current is sinusoidal and in phase with the utility voltage. Accordingly, only a bridge-type switch set is used in the single-phase to three-phase power conversion interface to simply the power circuit. A prototype is developed and tested to verify the performance of the proposed single-phase to three-phase power conversion interface.

  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. 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...

  6. Ferroelectric phase transition in Ga2Te3 single crystals

    Science.gov (United States)

    Gamal, G. A.; Abdalrahman, M. M.; Ashraf, M. I.; Eman, H. J.

    2005-01-01

    Measurements of the electrical conductivity and Hall effect were carried out in a wide temperature range (200-500 K) for Ga2Te3 crystals. The crystals were grown in single crystalline form by making a modification of the travelling heater method technique. The measurements revealed unusual observations in the electric conductivity and Hall mobility indicating the presence of some type of phase transitions at about 430 K. So, ferroelectric behavior was examined for confirming the presence of second-order (ferroelectric) phase transition. An energy gap of 1.21 eV and depth of the impurity center of 0.11 eV were found.

  7. 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.

  8. 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...

  9. Adduct Formation in ESI/MS by Mobile Phase Additives.

    Science.gov (United States)

    Kruve, Anneli; Kaupmees, Karl

    2017-05-01

    Adduct formation is a common ionization method in electrospray ionization mass spectrometry (ESI/MS). However, this process is poorly understood and complicated to control. We demonstrate possibilities to control adduct formation via mobile phase additives in ESI positive mode for 17 oxygen and nitrogen bases. Mobile phase additives were found to be a very effective measure for manipulating the formation efficiencies of adducts. An appropriate choice of additive may increase sensitivity by up to three orders of magnitude. In general, sodium adduct [M + Na] + and protonated molecule [M + H] + formation efficiencies were found to be in good correlation; however, the former were significantly more influenced by mobile phase properties. Although the highest formation efficiencies for both species were observed in water/acetonitrile mixtures not containing additives, the repeatability of the formation efficiencies was found to be improved by additives. It is concluded that mobile phase additives are powerful, yet not limiting factors, for altering adduct formation. Graphical Abstract ᅟ.

  10. 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...

  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. 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.

  13. 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

  14. 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........ The main elements of the PV control structure are: - a maximum power point tracker (MPPT) algorithm using the incremental conductance method; - a synchronization method using the phase-locked-loop (PLL), based on delay; - the input power control using the dc voltage controller and power feed...

  15. Effect of Maitland mobilization and exercises for the treatment of shoulder adhesive capsulitis: a single-case design.

    Science.gov (United States)

    Maricar, N; Shacklady, C; McLoughlin, L

    2009-04-01

    The purpose of this single-case design (ABCBC) was to investigate the response of shoulder motions, pain, and function to two commonly used physiotherapy management approaches. An individual with stage three shoulder adhesive capsulitis was treated with exercise (phase B) and exercise plus mobilization (phase C). Initially, a "baseline" phase (phase A) when treatment had not started was established for comparison. Two types of Maitland "accessory" glenohumeral mobilization techniques, anteroposterior mobilization in shoulder flexion and longitudinal caudad in shoulder abduction, were evaluated during phase C. The Shoulder Pain and Disability Index (SPADI) was used to monitor pain and functional disability, and four shoulder movements (flexion, abduction, internal, and external rotations) were measured. The results were evaluated by using single-case design analysis method of Split Middle Technique and visual observation. The SPADI scores deteriorated in phase A but improved in phase B1, C1, and B2. All four shoulder movements improved under both management approaches, although more gain in motion was observed when mobilizations were added to an exercise program. The exercise plus mobilization intervention shows promise as a cost-effective management. The deterioration in shoulder motion, pain, and function observed in phase A may suggest benefit of an earlier physiotherapy intervention.

  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. 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

  19. 77 FR 15369 - Mobility Fund Phase I Auction GIS Data of Potentially Eligible Census Blocks

    Science.gov (United States)

    2012-03-15

    ... FEDERAL COMMUNICATIONS COMMISSION [AU Docket No. 12-25; DA 12-355] Mobility Fund Phase I Auction... census blocks potentially eligible for Mobility Fund Phase I support to be offered in Auction 901. This...). SUPPLEMENTARY INFORMATION: This is a summary of the Mobility Fund Phase I Auction GIS Data for Potentially...

  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. 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...

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

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2016-01-01

    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......-phase applications as a promising harmonic mitigation solution. Experiments on single-phase grid-connected systems have verified the correctness of the relevant analysis and also the effectiveness of the tailor-made control solution in terms of good harmonic mitigation....

  3. 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.

  4. MPC of Single Phase Inverter for PV System

    OpenAIRE

    Irtaza M. Syed; Kaamran Raahemifar

    2014-01-01

    This paper presents a model predictive control (MPC) of a utility interactive (UI) single phase inverter (SPI) for a photovoltaic (PV) system at residential/distribution level. The proposed model uses single-phase phase locked loop (PLL) to synchronize SPI with the grid and performs MPC control in a dq reference frame. SPI model consists of boost converter (BC), maximum power point tracking (MPPT) control, and a full bridge (FB) voltage source inverter (VSI). No PI regula...

  5. 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...

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

    DEFF Research Database (Denmark)

    Liang, Jianing; Xu, Guoqing; Jian, Linni

    2011-01-01

    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......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...

  7. 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.

  8. 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.

  9. Regeneration of phase unlocked serial multiplexed DPSK signals in a single phase sensitive amplifier

    DEFF Research Database (Denmark)

    Guan, Pengyu; Da Ros, Francesco; Kjøller, Niels-Kristian

    2017-01-01

    We demonstrate phase-regeneration of phase unlocked OTDM-DPSK serial signals in a single phase sensitive amplifier through optical cross-phase modulation. The BER of an 8×10 Gbit/s OTDM-DPSK signal is improved by 2 orders of magnitude....

  10. 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...

  11. 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...

  12. 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...

  13. 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 report the first comprehensive experimental and theoretical study of the optical properties of single crystal phase quantum dots in InP nanowires. Crystal phase quantum dots are defined by a transition in the crystallographic lattice between zinc blende and wurtzite segments and therefore offe...

  14. 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)

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

    African Journals Online (AJOL)

    DR OKE

    Wavelet based techniques have been extensively used in various power engineering applications. Recently, wavelet has also been proposed to generate switching signal for single-phase pulse-width-modulated (PWM) dc-ac inverter. The main advantage of the wavelet modulated (WM) scheme is that a single synthesis ...

  16. Phase-predictable tuning of single-frequency optical synthesizers.

    Science.gov (United States)

    Rohde, Felix; Benkler, Erik; Puppe, Thomas; Unterreitmayer, Reinhard; Zach, Armin; Telle, Harald R

    2014-07-15

    We investigate the tuning behavior of a novel type of single-frequency optical synthesizers by phase comparison of the output signals of two identical devices. We achieve phase-stable and cycle-slip free frequency tuning over 28.1 GHz with a maximum zero-to-peak phase deviation of 62 mrad. In contrast to previous implementations of single-frequency optical synthesizers, no comb line order switching is needed when tuned over more than one comb line spacing range of the employed frequency comb.

  17. 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.)

  18. A single phase multilevel inverter as power converter for 3-phase ...

    African Journals Online (AJOL)

    A single phase multilevel inverter as power converter for 3-phase electric loads. ... m-phase maker was simulated using MATLAB and the results confirmed the excellent perfor-mance of the RBNPS. The listed advantages attained could be incorporated in the design and operation of a converter for an electric drive of a car.

  19. Aggregation kinetics of colloidal particles measured by gas-phase differential mobility analysis.

    Science.gov (United States)

    Tsai, D-H; Pease, L F; Zangmeister, R A; Tarlov, M J; Zachariah, M R

    2009-01-06

    We demonstrate the utility of electrospray gas-phase ion-mobility analysis as a new method to investigate nanoparticle flocculation, or aggregation. Au nanoparticle (Au-NP) solutions were sampled via electrospray (ES), followed by differential ion-mobility analysis (DMA) to determine the particle mobility distribution. Multimodal size distributions obtained with ES-DMA indicated the presence of single Au-NPs (monomer) as well as larger Au-NP clusters such as dimers, trimers, and tetramers under specific solution conditions. The fraction of each aggregate species as a function of time was quantitatively characterized, from which the degree of aggregation, aggregation rate, and stability ratio at different ionic strengths were determined. The latter enabled the extraction of a surface potential (or surface charge density) of 64 +/- 2 mV for 10 nm Au-NPs, which is in good agreement with values obtained from other methods, thus validating our approach. Our results show that ES-DMA is a valuable tool for quantitatively probing the early stages of colloidal aggregation or as a preparatory tool for the size election of aggregates.

  20. 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

    Eco-production and logistics with environmental consciousness are playing a larger role in manufacturing firms. They involve scheduling, planning, developing and implementing manufacturing processes and technologies that are required not only to keep productivity high but also to respond....... 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...... is to minimize total traveling time of the robot with the smallest consumed amount of battery energy in a given planning horizon. A mixed-integer programming (MIP) model is developed to find the optimal solutions for the problem. Two case studies are implemented at an impeller production line to demonstrate...

  1. Instantaneous power flow determination for single-phase UPFC

    Energy Technology Data Exchange (ETDEWEB)

    Dobrucky, B.; Drozdy, S.; Pokorny, M.; Pavlanin, R. [Zilina Univ., Zilina (Slovakia)

    2007-07-01

    The parallel shunt active filter in a unified power flow conditioner (UPFC) can filter and compensate the reactive power of basic and higher current harmonics. This paper reported on a study in which a new theory of orthogonal transform was used to control a single-phase UPFC system and transform it into a two-axes system. In addition to estimating the load current phase shifts, the study also determined the instantaneous active and reactive powers. The new theory is based on the premise that ordinary single-phase quantity can be complemented by a virtual fictitious phase so that both of them will create an orthogonal system, as is usual in three-phase systems. The theory uses efficient methods of analysis, such as time-sub-optimal determination of fundamental harmonics; average- and/or root-mean-square values; or instantaneous reactive power methods. The load current phase shift can be used to compensate for voltage drops. This paper outlined a practical application of the method in a case of active and reactive power determination for single-phase UPFC. It also presented some examples of the successful simulation experiments results focused on regulation output voltage of UPFC. 9 refs., 13 figs., 1 appendix.

  2. 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

  3. 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.

  4. 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...... investigates the latest SJ devices in order to set a reference for future research on improvement over silicon (Si) attained with the introduction of wide bandgap devices in single phase PFC applications. The obtained results show that the latest generation of SJ devices set a new benchmark for its wide...

  5. 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.

  6. 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.

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

    Science.gov (United States)

    Li, Shengnan; Tian, Minglei; Row, Kyung Ho

    2010-01-01

    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. PMID:20559512

  8. 77 FR 7152 - Mobility Fund Phase I Auction Scheduled for September 27, 2012; Comment Sought on Competitive...

    Science.gov (United States)

    2012-02-10

    ... FEDERAL COMMUNICATIONS COMMISSION [AU Docket No. 12-25; DA 12-121] Mobility Fund Phase I Auction... auction to award $300 million in one-time Mobility Fund Phase I support scheduled to commence on September... Spectrum Access Division: For Mobility Fund Phase I questions: Sayuri Rajapakse at (202) 418-0660; for...

  9. 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...

  10. 78 FR 21355 - Tribal Mobility Fund Phase I Auction Scheduled for October 24, 2013; Comment Sought on...

    Science.gov (United States)

    2013-04-10

    ... FEDERAL COMMUNICATIONS COMMISSION [AU Docket No. 13-53; DA 13-323] Tribal Mobility Fund Phase I... announce a reverse auction to award up to $50 million in one-time Tribal Mobility Fund Phase I support... Access Division: For Tribal Mobility Fund Phase I questions: Patricia Robbins at (202) 418-0660; for...

  11. 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...

  12. 78 FR 56875 - Tribal Mobility Fund Phase I Auction Rescheduled for December 19, 2013; Notice and Filing...

    Science.gov (United States)

    2013-09-16

    ... FEDERAL COMMUNICATIONS COMMISSION [AU Docket No. 13-53; DA 13-1672] Tribal Mobility Fund Phase I... requirements for a reverse auction to award up to $50 million in one-time Tribal Mobility Fund Phase I support..., Auctions and Spectrum Access Division: For Tribal Mobility Fund Phase I questions: Patricia Robbins at (202...

  13. 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.

  14. 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

  15. 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.

  16. 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...

  17. 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,...

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

    African Journals Online (AJOL)

    2012-11-03

    Nov 3, 2012 ... The paper reports the derivation of the steady- state equivalent circuit of a single phase transfer ... series opposition between the two halves of the ma- ..... from its equivalent circuit of fig 6 for different values of slip. Impedance due to forward field. Zf = Rf + jXf = Rr. 2(2s - 1). + jxr. 2. (19) in parallel with jxm. 2.

  19. 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...

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

    African Journals Online (AJOL)

    Existing single phase induction motors exhibit low starting torque. Moreover, during accelerating time and at steady state, they produce a significant level of torque pulsations which gives rise to noise and vibration in the machine. As part of efforts to mitigate these problems, a performance improvement strategy using a PWM ...

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

    African Journals Online (AJOL)

    Experimental Implementation of SPWM VSI with R-L Load. 3. Figure 2: Switching pattern of the proposed single-phase, three-level PWM inverter. Figure 3: Prototype setup. (a) Power circuits for both inverters. (b) Logic and Driver circuits. Nigerian Journal of Technology. Vol. 31, No. 1, March 2012.

  2. 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 ...

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

    African Journals Online (AJOL)

    In this paper a new control strategy for series active filter has been proposed for improvement of power quality problems in single phase system. Since the non linear loads in the system comprises of both voltage source harmonic and current source harmonic loads and the dominancy of each type of load varies from time to ...

  4. 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...

  5. 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

  6. 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...

  7. Reevaluation of ethanol as organic modifier for use in HPLS-RP mobile phases

    Directory of Open Access Journals (Sweden)

    Ribeiro Ricardo L. V.

    2004-01-01

    Full Text Available Ethanol:water mixtures have been reevaluated for use as reversed phase mobile phases. Optimization of the chromatographic conditions for both C8 and C18 columns was carried out through a factorial design which evaluates temperature, ethanol concentration and mobile phase flow rate. With the C8 stationary phase, peak asymmetries were not significantly altered at the different points in the factorial design while the retention factors and resolutions were somewhat lower at higher temperatures, where the viscosity of EtOH is lower. Similar observations were obtained with the C18 phase. The efficiency of the ethanol:water mobile phase for the separation of mixtures containing neutral and basic compounds was compared with those obtained using methanol:water and acetonitrile:water mobile phases. Ethanol was shown to be a good organic modifier for RP-HPLC, with good chromatographic properties. This, considering the much lower toxicity of ethanol, the facility of its disposal, and its favorable cost, should make ethanol:H2O the mobile phase of choice for many RP-HPLC applications.

  8. 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.

  9. 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)

  10. Asymmetrical stabilization and mobilization exploited during static single leg stance and goal directed kicking.

    Science.gov (United States)

    King, Adam C; Wang, Zheng

    2017-08-01

    The motor control properties of the right and left legs are dependent on the stabilization and mobilization features of the motor tasks. The current investigation examined the right and left leg control differences - interlateral asymmetries - during static single leg stance and dynamic goal directed kicking with an emphasis of the asymmetrical stabilization and mobilization components of movements. Ten young, healthy, right-leg preferred individuals with minimal kicking experience completed both tests on each limb. During static single leg stance, participants were requested to stand as still as possible with one leg in contact with a force platform. Interlateral asymmetries of the standing leg were quantified using postural variability measures of the center of pressure (COP) standard deviation in the anterior-posterior (SD-COP AP ) and medial-lateral (SD-COP ML ) directions, resultant COP length and velocity, and 95% COP elliptical area. During dynamic goal directed kicking, participants stood on two adjacent force platforms in a side-by-side foot position and kicked a soccer ball toward three different directions as soon as they received an auditory cue of kicking. Three targets were located -30°, 0° or 30° in front and 3.05 m away from the participants' midline. Participants kicked the ball toward the targets with each of their feet. The vertical ground reaction force (vGRF) of the kicking leg was used to define the preparation (from above two standard deviations of vGRF baseline to toe-off) and swing (from toe-off to toe-return) phases of dynamic kicking. To determine the presence of interlateral asymmetries during dynamic kicking, the magnitude and timing of the anticipatory postural adjustments (APA) during the preparation phase of kicking were quantified using the lateral net COP (COPnet-ML) time series derived from both force platforms. Postural variability measures of the support leg and the kinematic joint range of motion (JROM) trajectories of the

  11. Improved PLL structures for single-phase grid inverters

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Teodorescu, Remus; Blaabjerg, Frede

    2005-01-01

    of the reference signals. This paper presents two improved phase-locked-loop (PLL) methods for single-phase grid connected systems. The investigated PLL methods are based on a transport delay method and an inverse Park transformation method. The improvements in the case of using the delay-based PLL are: non......-frequency dependent and better filtering of the harmonics. For the other investigated PLL method based on inverse Park transformation the improvement consists of better filtering of the harmonics. Experimental results validate the effectiveness of the two proposed methods....

  12. Dynamics Assessment of Advanced Single-Phase PLL Structures

    DEFF Research Database (Denmark)

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

    2013-01-01

    , and desired performance under frequency-varying and harmonically distorted grid conditions. Despite the wide acceptance and use of these two advanced PLLs, no comprehensive design guidelines to fine-tune their parameters have been reported yet. Through a detailed mathematical analysis it is shown......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...

  13. Evaluation of thromboembolic disease using single dose dual phase scintigraphy

    International Nuclear Information System (INIS)

    Sharma, A.R.; Charan, S.; Silva, I.

    2004-01-01

    Introduction: Clinical presentation of thromboembolic disease (TED) is caused by three mechanisms 1) obstruction to venous outflow 2) vascular inflammation and 3) pulmonary emboli. Single Dose (Tc-99m MAA) Dual Phases (Veno-Pulmonary) scintigraphy is theoretically capable of evaluating two of three above mentioned patho-physiological factors. Therefore, a prospective study was designed to explore potential of Single Dose Dual Phase (SDDP) scintigraphy in the evaluation of thromboembolic disease. Materials and methods: Sixty consecutive patients with high clinical likelihood of thromboembolic disease (onset of painful and edematous lower limb, chest pain, shortness of breath, presence of risk factors for DVT, H/o of previous episode of DVT, right ventricular strain on ECHO, hypoxaemia on blood gas analysis), were included in this study. There were 43 men and 17 women (mean age 36 years). They were subjected to single dose dual phase (SDDP) scintigraphy using Tc-99m MAA (4 mci). Firstly venous phase of imaging was obtained with simultaneous injection of Tc-99m MAA diluted in 10 ml normal saline in syringe into superficial veins of dorsum of both feet (large volume continuous flow technique) in whole body acquisition mode on Dual Detectors Gamma Camera; followed by lung perfusion scintigraphy in conventional projections as second phase of study. Venous phase (Venography) was interpreted as per Ziffer's criteria in four venous segments (Unpaired- Inferior Vena Cava, 3 paired - Iliac, Femoral and Popliteal). Interpretation of lung perfusion scan was made as per PIOPED Criteria. Results: Forty-one of sixty patients (67%) showed scintigraphic evidence of venous occlusion (DVT) during venous phase. Out of these, 17 patients eventually had high probability lung scan for pulmonary embolism (29%). None of the patient with negative venous phase (n=19) showed perfusion defects on lung perfusion scan. Venous thrombosis most commonly affected the left lower limb (n=29, 71%). In 5

  14. Effects of single particle on shape phase transitions and phase coexistence in odd-even nuclei

    Science.gov (United States)

    Yu, Xiang-Ru; Hu, Jing; Li, Xiao-Xue; An, Si-Yu; Zhang, Yu

    2018-02-01

    A classical analysis of shape phase transitions and phase coexistence in odd-even nuclei has been performed in the framework of the interacting boson-fermion model. The results indicate that the effects of a single particle may influence different types of transitions in different ways. Especially, it is revealed that phase coexistence can clearly emerge in the critical region and thus be taken as a indicator of the shape phase transitions in odd-even nuclei. Supported by National Natural Science Foundation of China (11375005)

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

    African Journals Online (AJOL)

    Objectives: This study investigated the presence of MAS codes on medicines mandated by NAFDAC to have the code and a preliminary assessment of MAS ... 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 ...

  16. 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...

  17. 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)

  18. 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...

  19. 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...

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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...

  5. 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)

  6. 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

    The first few minutes of play, commonly referred to as the onboarding phase, of Free-to-Play mobile games typically display a substantial churn rate among new players. It is therefore vital for designers to effectively evaluate this phase to investigate its satisfaction of player expectations....... 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...... as a range of self-reported proxy measures including: a) stimulated recall, engagement graphs, b) flow state survey and c) post-game experience questionnaire. These techniques were applied across 28 participants using three mobile Free-to-Play titles from different genres. This paper makes two important...

  7. Task Phase Recognition for Highly Mobile Workers in Large Building Complexes

    DEFF Research Database (Denmark)

    Stisen, Allan; Mathisen, Andreas; Krogh, Søren

    2016-01-01

    Being aware of activities of co-workers is a basic and vital mechanism for efficient work in highly distributed work settings. Thus, automatic recognition of the task phases the mobile workers are currently (or have been) in has many applications, e.g., efficient coordination of tasks by visualiz......Being aware of activities of co-workers is a basic and vital mechanism for efficient work in highly distributed work settings. Thus, automatic recognition of the task phases the mobile workers are currently (or have been) in has many applications, e.g., efficient coordination of tasks...... by visualizing coworkers’ task progress, automatic notifications based on context awareness, and record filing of task statuses and completions. This paper presents methods to sense and detect highly mobile workers’ tasks phases in large building complexes. Large building complexes restrict the technologies...

  8. Modeling Dynamics and Exploring Control of a Single-Wheeled Dynamically Stable Mobile Robot with Arms

    Science.gov (United States)

    2006-08-31

    Takahashi, T., and Kawamura, A. "A Study on the Zero Moment Point Measurement for Biped Walking Robots ", Proc. of the 7th International Workshop on...STABLE MOBILE ROBOT WITH ARMS" 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER CAPT SCHEARER ERIC M 5e. TASK NUMBER 5f. WORK...Std. Z39.18 Modeling Dynamics and Exploring Control of a Single-Wheeled Dynamically Stable Mobile Robot with Arms Eric M. Schearer CMU-RI-TR-06-37

  9. 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

  10. 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.

  11. Solution Concept of Modular Single Phase Active Power Filters

    Directory of Open Access Journals (Sweden)

    Marek Roch

    2006-01-01

    Full Text Available This paper investigates a modular or a decentralised single-phase active power filter control strategy. It is based on the evaluation of the harmonic reference load currents for the active power filter blocks operating under specific harmonic frequencies. The underlying principle of the modular active power filter is explained and it is shown how the required reference harmonic currents can be evaluated. Simulation results demonstrated the improvement in the dynamic performance of the modular active power filter presented here in comparison with the conventional type.

  12. 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...... components compared with its counterparts and only one switch conducts during the active states which enhance the inverter efficiency. The proposed inverter is analyzed in details and compared with some existing topologies. The performance of the proposed inverter is validated using the simulation results....

  13. 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...... 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...... of the proposed PSU and its power management strategy, the loads among different phases can be properly supplied and the energy can be fully utilized as well as obtaining better load sharing. Simulation and experimental results are provided to demonstrate the validity of the proposed hybrid microgrid structure...

  14. 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.

  15. Synthesis and magnetic properties of single phase titanomagnetites

    Energy Technology Data Exchange (ETDEWEB)

    Schoenthal, W., E-mail: wms@andrew.cmu.edu; Liu, X.; Cox, T.; Laughlin, D. E.; McHenry, M. E. [Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Mesa, J. L.; Diaz-Michelena, M. [Instituto Nacional de Tecnica Aeroespacial, Madrid (Spain); Maicas, M. [Universidad Politecnica de Madrid, ISOM-ETSIT, Madrid (Spain)

    2014-05-07

    The focus of this paper is the study of cation distributions and resulting magnetizations in titanomagnetites (TMs), (1−x)Fe{sub 3}O{sub 4−x}Fe{sub 2}TiO{sub 4} solid solutions. TM remnant states are hypothesized to contribute to planetary magnetic field anomalies. This work correlates experimental data with proposed models for the TM pseudobinary. Improved synthesis procedures are reported for single phase Ulvöspinel (Fe{sub 2}TiO{sub 4}), and TM solid solutions were made using solid state synthesis techniques. X-ray diffraction and scanning electron microscopy show samples to be single phase solid solutions. M-H curves of TM75, 80, 85, 90, and 95 (TMX where X = at. % of ulvöspinel) were measured using a Physical Property Measurement System at 10 K, in fields of 0 to 8 T. The saturation magnetization was found to be close to that predicted by the Neel model for cation distribution in TMs. M-T curves of the remnant magnetization were measured from 10 K to 350 K. The remnant magnetization was acquired at 10 K by applying an 8 T field and then releasing the field. Experimental Neel temperatures are reported for samples in the Neel model ground state.

  16. 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

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

    Science.gov (United States)

    2016-09-01

    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...The addition of a passive filter proved to minimize the conducted EMI for a single -phase grid-tied inverter. 14. SUBJECT TERMS single -phase

  18. 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.

  19. 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...

  20. 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...

  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. 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.

  3. Investigations of high mobility single crystal chemical vapor deposition diamond for radiotherapy photon beam monitoring

    Science.gov (United States)

    Tromson, D.; Descamps, C.; Tranchant, N.; Bergonzo, P.; Nesladek, M.; Isambert, A.

    2008-03-01

    The intrinsic properties of diamond make this material theoretically very suitable for applications in medical physics. Until now ionization chambers have been fabricated from natural stones and are commercialized by PTW, but their fairly high costs and long delivery times have often limited their use in hospital. The properties of commercialized intrinsic polycrystalline diamond were investigated in the past by many groups. The results were not completely satisfactory due to the nature of the polycrystalline material itself. In contrast, the recent progresses in the growth of high mobility single crystal synthetic diamonds prepared by chemical vapor deposition (CVD) technique offer new alternatives. In the framework of the MAESTRO project (Methods and Advanced Treatments and Simulations for Radio Oncology), the CEA-LIST is studying the potentialities of synthetic diamond for new techniques of irradiation such as intensity modulated radiation therapy. In this paper, we present the growth and characteristics of single crystal diamond prepared at CEA-LIST in the framework of the NoRHDia project (Novel Radiation Hard CVD Diamond Detector for Hadrons Physics), as well as the investigations of high mobility single crystal CVD diamond for radiotherapy photon beam monitoring: dosimetric analysis performed with the single crystal diamond detector in terms of stability and repeatability of the response signal, signal to noise ratio, response speed, linearity of the signal versus the absorbed dose, and dose rate. The measurements performed with photon beams using radiotherapy facilities demonstrate that single crystal CVD diamond is a good alternative for air ionization chambers for beam quality control.

  4. 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.

  5. 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,...

  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. 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...

  8. 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...

  9. Model Based Control of Single-Phase Marine Cooling Systems

    DEFF Research Database (Denmark)

    Hansen, Michael

    2014-01-01

    these systems. Traditionally, control for this type of cooling system has been limited to open-loop control of pumps combined with a couple of local PID controllers for bypass valves to keep critical temperatures within design limits. This research considers improvements in a retrofit framework to the control...... linearization, an H∞-control design is applied to the resulting linear system. Disturbance rejection capabilities and robustness of performance for this control design methodology is compared to a baseline design derived from classical control theory. This shows promising results for the nonlinear robust design......This thesis is concerned with the problem of designing model-based control for a class of single-phase marine cooling systems. While this type of cooling system has been in existence for several decades, it is only recently that energy efficiency has become a focus point in the design and operation...

  10. Modeling of a single-phase photovoltaic inverter

    Energy Technology Data Exchange (ETDEWEB)

    Maris, T.I. [Department of Electrical Engineering, Technological Educational Institute of Chalkida, 334 40 Psachna Evias (Greece); Kourtesi, St. [Hellenic Public Power Corporation S.A., 22 Chalcocondyli Str., 104 32 Athens (Greece); Ekonomou, L. [Hellenic American University, 12 Kaplanon Str., 106 80 Athens (Greece); Fotis, G.P. [National Technical University of Athens, School of Electrical and Computer Engineering, High Voltage Laboratory, 9 Iroon Politechniou St., Zografou, 157 80 Athens (Greece)

    2007-11-06

    The paper presents the design of a single-phase photovoltaic inverter model and the simulation of its performance. Furthermore, the concept of moving real and reactive power after coupling this inverter model with an a.c. source representing the main power distribution grid was studied. Brief technical information is given on the inverter design, with emphasis on the operation of the circuit used. In the technical information section, a description of real and reactive power components is given with special reference to the control of these power components by controlling the power angle or the difference in voltage magnitudes between two voltage sources. This a.c. converted voltage has practical interest, since it is useful for feeding small house appliances. (author)

  11. Benchmarks for single-phase flow in fractured porous media

    Science.gov (United States)

    Flemisch, Bernd; Berre, Inga; Boon, Wietse; Fumagalli, Alessio; Schwenck, Nicolas; Scotti, Anna; Stefansson, Ivar; Tatomir, Alexandru

    2018-01-01

    This paper presents several test cases intended to be benchmarks for numerical schemes for single-phase fluid flow in fractured porous media. A number of solution strategies are compared, including a vertex and two cell-centred finite volume methods, a non-conforming embedded discrete fracture model, a primal and a dual extended finite element formulation, and a mortar discrete fracture model. The proposed benchmarks test the schemes by increasing the difficulties in terms of network geometry, e.g. intersecting fractures, and physical parameters, e.g. low and high fracture-matrix permeability ratio as well as heterogeneous fracture permeabilities. For each problem, the results presented are the number of unknowns, the approximation errors in the porous matrix and in the fractures with respect to a reference solution, and the sparsity and condition number of the discretized linear system. All data and meshes used in this study are publicly available for further comparisons.

  12. Realization of single-phase single-stage grid-connected PV system

    Directory of Open Access Journals (Sweden)

    Osama M. Arafa

    2017-05-01

    Full Text Available This paper presents a single phase single stage grid-tied PV system. Grid angle detection is introduced to allow operation at any arbitrary power factor but unity power factor is chosen to utilize the full inverter capacity. The system ensures MPPT using the incremental conductance method and it can track the changes in insolation level without oscillations. A PI voltage controller and a dead-beat current controller are used to ensure high quality injected current to the grid. The paper investigates the system structure and performance through numerical simulation using Matlab/Simulink. An experimental setup controlled by the MicrolabBox DSP prototyping platform is utilized to realize the system and study its performance. The precautions for smooth and safe system operation including the startup sequence are fully considered in the implementation.

  13. 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.

  14. Multimodal chromatography: Characterization of protein binding and selectivity enhancement through mobile phase modulators.

    Science.gov (United States)

    Wolfe, Leslie S; Barringer, Cartney P; Mostafa, Sigma S; Shukla, Abhinav A

    2014-05-02

    The unique selectivity of mixed mode chromatography resins is driving increasing utilization of these novel selectivities into bioprocess applications. There is a need for improved fundamental understanding of protein binding to these stationary phases to enable the development of efficient and robust purification processes. A panel of four monoclonal antibodies and two model proteins were employed to characterize protein interaction with a mixed-mode chromatographic resin comprising a hydrophobic ligand with cation-exchange functionality. Binding of these proteins was studied as a function of salt concentration and pH in the presence of various mobile phase modulators. This knowledge was applied towards screening mobile phase modulators that could selectively decrease host cell protein levels during monoclonal antibody purification. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Single Scattering Detection in Turbin Media Using Single-Phase Structured Illumination Filtering

    Science.gov (United States)

    Berrocal, E.; Johnsson, J.; Kristensson, E.; Alden, M.

    2012-05-01

    This work shows a unique possibility of visualizing the exponential intensity decay due to light extinction, when laser adiation propagates through a homogeneous scattering edium. This observation implies that the extracted intensity mostly riginates from single scattering events. The filtering of this single light scattering intensity is performed by means of a single-phase structured illumination filtering approach. Results from numerical Monte Carlo simulation confirm the experimental findings for an extinction coefficient of μ_e = 0.36 mm^-1. This article demonstrates an original and reliable way of measuring the extinction coefficient of particulate turbid media based on sidescattering imaging. Such an approach has capabilities to replace the commonly used transmission measurement within the intermediate single-to multiple scattering regime where the optical depth ranges between 1 procedure and set-up. Applications of the technique has potential in probing challenging homogeneous scattering media, such as biomedical tissues, turbid emulsions, etc, in situations where dilution cannot be applied and where conventional transmission measurements fail.

  16. 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.

  17. 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)

  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 Balancing by Means of Electric Vehicles Single-Phase Connection Shifting in a Low Voltage Danish Grid

    DEFF Research Database (Denmark)

    Lico, Pasqualino; Marinelli, Mattia; Knezovic, Katarina

    2015-01-01

    In Denmark, household consumers are supplied with three phase with neutral cable. In addition, the distribution service operator cannot decide to which phase electrical appliance are connected. The technician who realizes the installation connects the loads according to his technical expertise...... stations are equipped with single-phase converters. According to the designed control strategy, the charging spot can select the phase to be used for the charge. The selection is done according to a phase voltage measurement....

  20. 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

  1. The development and validation of a novel outcome measure to quantify mobility in the dysvascular lower extremity amputee: the amputee single item mobility measure

    Science.gov (United States)

    Norvell, Daniel C; Williams, Rhonda M; Turner, Aaron P; Czerniecki, Joseph M

    2016-01-01

    Objective: This study describes the development and psychometric evaluation of a novel patient-reported single-item mobility measure. Design: Prospective cohort study. Setting: Four Veteran’s Administration Medical Centers. Subjects: Individuals undergoing their first major unilateral lower extremity amputation; 198 met inclusion criteria; of these, 113 (57%) enrolled. Interventions: None. Main measures: The Amputee Single Item Mobility Measure, a single item measure with scores ranging from 0 to 6, was developed by an expert panel, and concurrently administered with the Locomotor Capabilities Index-5 (LCI-5) and other outcome measures at six weeks, four months, and 12 months post-amputation. Criterion and construct validity, responsiveness, and floor/ceiling effects were evaluated. Responsiveness was assessed using the standardized response mean. Results: The overall mean 12-month Amputee Single Item Mobility Measure score was 3.39 ±1.4. Scores for transmetatarsal, transtibial, and transfemoral amputees were 4.2 (±1.3), 3.2 (±1.5), and 2.9 (±1.1), respectively. Amputee Single Item Mobility Measure scores demonstrated “large” and statistically significant correlations with the LCI-5 scores at six weeks (r = 0.72), four months (r = 0.81), and 12 months (r = 0.86). At four months and 12 months, the correlation between Amputee Single Item Mobility Measure scores and hours of prosthetic use were r = 0.69 and r = 0.66, respectively, and between Amputee Single Item Mobility Measure scores and Trinity Amputation and Prosthesis Experience Scales functional restriction scores were r = 0.45 and r = 0.67, respectively. Amputee Single Item Mobility Measure scores increased significantly from six weeks to 12 months post-amputation. Minimal floor/ceiling effects were demonstrated. Conclusions: In the unilateral dysvascular amputee, the Amputee Single Item Mobility Measure has strong criterion and construct validity, excellent

  2. Mobilities

    DEFF Research Database (Denmark)

    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...... for all students and scholars with an interest in the ‘mobilities turn’ and its contributions to a deeper understanding of the contemporary and mobile world. The entries chosen all are amongst the most creative, thought provoking, and thoughtful of this diverse field of analysis and thought. The selection...

  3. 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)

  4. Servo characteristics of single-phase spindle motor in DVD-ROM

    Science.gov (United States)

    Wang, KingYin; Kuei, ChingPing; Chang, SungSan; Lee, YaoYu; Kuo, YuHung

    2000-07-01

    The single-phase DC motor has the low-cost advantage over 3- phase DC motor owing to its easy-assembling and high yield- rate, however, it has larger torque ripple and cogging torque. Single-phase DC motor is currently applied to low profit margin products such as cooling fan. In order to utilize single-phase DC motor to high precision system, for instance, DVD (Digital Versatile Disk), the vibration caused by torque ripple and cogging torque needs to be solved. In this paper, focusing error, tracking error, seeking ability and some velocity control performances are studied when single-phase DC motor is used in DVD related products.

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

    OpenAIRE

    Menxi Xie; CanYan Zhu; BingWei Shi; Yong Yang

    2017-01-01

    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...

  6. Performance Improvement of Single Phase Inverter using SPWM

    Science.gov (United States)

    Gavaskar Reddy, B., Dr; Maheswari, L., Dr; Ganeswari Kale, Adi

    2017-08-01

    This paper concentrates on modelling and simulation of single phase inverter as a frequency changer modulated by Pulse Width Modulation (PWM). An inverter is a circuit that converts DC sources to AC sources. Pulse Width Modulation is a method that utilization as an approach to abatement add up to harmonic distortion in inverter circuit. The model is executed utilizing MATLAB/Simulink software with the SimPower System Block Set in light of PC simulation. PC simulation assumes an imperative part in the plan, investigation, and assessment of force electronic converter and their controller. MATLAB is a successful instrument to examine a PWM inverter. Preferences of utilizing MATLAB are the accompanying: Faster reaction, accessibility of different simulation devices and utilitarian squares and the nonappearance of joining issues. Safe-replacement methodology need be actualized is to explain exchanging Transients. In this way, Insulated Gate Bipolar Transistor (IGBT) is use as exchanging gadgets. IGBT is ideal since it is anything but difficult to control and low misfortunes. The outcome from Simulink was checked utilizing MATLAB simulation.

  7. 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.

  8. 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.

  9. 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.

  10. Massive fermions with low mobility in antiferromagnet orthorhombic CuMnAs single crystals

    Science.gov (United States)

    Zhang, Xiao; Sun, Shanshan; Lei, Hechang

    2017-12-01

    We report the physical properties of orthorhombic o -CuMnAs single crystal, which is predicted to be a topological Dirac semimetal with magnetic ground state and inversion symmetry broken. o -CuMnAs exhibits an antiferromagnetic (AFM) transition with TN˜312 K . Further characterizations of magnetic properties suggest that the AFM order may be canted with the spin orientation in the b c plane. Small isotropic magnetoresistance and linearly field-dependent Hall resistivity with positive slope indicate that single hole-type carries with high density and low mobility dominate the transport properties of o -CuMnAs . Furthermore, the result of low-temperature heat capacity shows that the effective mass of carriers is much larger than those in typical topological semimetals. These results imply that the carriers in o -CuMnAs exhibit remarkably different features from those of Dirac fermions predicted in theory.

  11. 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

  12. 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...

  13. Single-molecule study of molecular mobility in the cytoplasm of Escherichia coli

    Science.gov (United States)

    Lill, Yoriko; Kaserer, Wallace A.; Newton, Salete M.; Lill, Markus; Klebba, Phillip E.; Ritchie, Ken

    2012-08-01

    The cytoplasm of bacterial cells is filled with individual molecules and molecular complexes that rely on diffusion to bring them together for interaction. The mobility of molecules in the cytoplasm has been characterized by several techniques mainly using fluorescent probes and ensemble methods. In order to probe the microenvrionment inside the cytoplasm as viewed by an individual molecule, we have studied single green fluorescent proteins (GFPs) diffusing in the cytoplasm of Escherichia coli cells at observation at rates ranging from 60 to 1000 Hz. Over long times the diffusion shows confinement due to the geometry of the cells themselves. A simulation in model cells using the actual distribution of cell sizes found in the experiments describes accurately the experimental results as well as reveals a short time diffusion coefficient that agrees well with that determined by ensemble methods. Higher short time diffusion coefficients can be obtained by filling the simulated cell with small spheres modeling cytoplasmic molecules and, depending on the density of particles included in the modeled cytoplasm, can approach the diffusion coefficient of GFPs found in water. Thus, single-molecule tracking combined with analysis using simple simulation of Brownian motion is able to reveal the main contributors to the GFP mobility in the cytoplasm of E. coli.

  14. Roflumilast - A reversible single-crystal to single-crystal phase transition at 50 °C

    Science.gov (United States)

    Viertelhaus, Martin; Holst, Hans Christof; Volz, Jürgen; Hummel, Rolf-Peter

    2013-01-01

    Roflumilast is a selective phosphodiesterase type 4 inhibitor and is marketed under the brand names Daxas®, Daliresp® and Libertec®. A phase transition of the drug substance roflumilast was observed at 50 °C. The low temperature form, the high temperature form and the phase transition were characterised by differential scanning calorimetry, variable temperature powder X-ray diffraction and single crystal X-ray diffraction, Raman spectroscopy and solid state NMR spectroscopy. The phase transition of roflumilast at 50 °C is completely reversible, the high temperature form cannot be stabilised by quench cooling and the phase transition does not influence the quality of the active pharmaceutical ingredient (API) and the drug product. It was observed to be a single crystal to single crystal phase transition.

  15. 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 establish...

  16. Hematopoietic stem cell mobilization using plerixafor – single center experience at the University medical centre Ljubljana

    Directory of Open Access Journals (Sweden)

    Matjaž Sever

    2012-12-01

    Conclusions: Plerixafor is a new highly successful mobilizing agent in high-risk patients or patients with previously failed mobilization. According to our experience, 13 (81 % poor mobilizers collected a sufficient amount of HSC on plerixafor to proceed to transplant.

  17. Single Molecule Imaging Deciphers the Relation between Mobility and Signaling of a Prototypical G Protein-coupled Receptor in Living Cells.

    Science.gov (United States)

    Veya, Luc; Piguet, Joachim; Vogel, Horst

    2015-11-13

    Lateral diffusion enables efficient interactions between membrane proteins, leading to signal transmission across the plasma membrane. An open question is how the spatiotemporal distribution of cell surface receptors influences the transmembrane signaling network. Here we addressed this issue by studying the mobility of a prototypical G protein-coupled receptor, the neurokinin-1 receptor, during its different phases of cellular signaling. Attaching a single quantum dot to individual neurokinin-1 receptors enabled us to follow with high spatial and temporal resolution over long time regimes the fate of individual receptors at the plasma membrane. Single receptor trajectories revealed a very heterogeneous mobility distribution pattern with diffusion constants ranging from 0.0005 to 0.1 μm(2)/s comprising receptors freely diffusing and others confined in 100-600-nm-sized membrane domains as well as immobile receptors. A two-dimensional representation of mobility and confinement resolved two major, broadly distributed receptor populations, one showing high mobility and low lateral restriction and the other showing low mobility and high restriction. We found that about 40% of the receptors in the basal state are already confined in membrane domains and are associated with clathrin. After stimulation with an agonist, an additional 30% of receptors became further confined. Using inhibitors of clathrin-mediated endocytosis, we found that the fraction of confined receptors at the basal state depends on the quantity of membrane-associated clathrin and is correlated to a significant decrease of the canonical pathway activity of the receptors. This shows that the high plasticity of receptor mobility is of central importance for receptor homeostasis and fine regulation of receptor activity. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. Controlling geometric phase optically in a single spin in diamond

    Science.gov (United States)

    Yale, Christopher G.

    Geometric phase, or Berry phase, is an intriguing quantum mechanical phenomenon that arises from the cyclic evolution of a quantum state. Unlike dynamical phases, which rely on the time and energetics of the interaction, the geometric phase is determined solely by the geometry of the path travelled in parameter space. As such, it is robust to certain types of noise that preserve the area enclosed by the path, and shows promise for the development of fault-tolerant logic gates. Here, we demonstrate the optical control of geometric phase within a solid-state spin qubit, the nitrogen-vacancy center in diamond. Using stimulated Raman adiabatic passage (STIRAP), we evolve a coherent dark state along `tangerine slice' trajectories on the Bloch sphere and probe these paths through time-resolved state tomography. We then measure the accumulated geometric phase through phase reference to a third ground spin state. In addition, we examine the limits of this control due to adiabatic breakdown as well as the longer timescale effect of far-detuned optical fields. Finally, we intentionally introduce noise into the experimental control parameters, and measure the distributions of the resulting phases to probe the resilience of the phase to differing types of noise. We also examine this robustness as a function of traversal time as well as the noise amplitude. Through these studies, we demonstrate that geometric phase is a promising route toward fault-tolerant quantum information processing. This work is supported by the AFOSR, the NSF, and the German Research Foundation.

  19. Optimization of mobile phase for separation of carbohydrates in honey by high performance liquid chromatography using a mixture design

    Directory of Open Access Journals (Sweden)

    Cano Cristiane B.

    2006-01-01

    Full Text Available A mixture design was used to optimize the mobile phase composition for separation of carbohydrates in honey by High Performance Liquid Chromatography. Nine ternary acetronitrile, water and ethyl acetate mobile phases corresponding to a simplex centroid design with axial points were test to separate those carbohydrates most frequently encountered in honey samples. The results suggest that a special cubic model accurately describes changes in the proportions of these solvents in the mobile phase close to the region of optimal peak separation. The addition of a third solvent, ethyl acetate, to binary mobile phase of water and acetonitrile permitted a significant improvement in carbohydrate separation that can be applied to the quantitative analysis of these compounds in honey.

  20. 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.

  1. A design of a two-phase permanent magnet vibration motor used for mobile phones

    Science.gov (United States)

    Chung, Shi-Uk; Hwang, Sang-Moon; Kim, Tae-Jong; Hwang, Gun-Yong; Kang, Beom-Soo

    2002-05-01

    With the advent of the telecommunications era, a mobile phone becomes a necessary communication device in modern society. However, a paging signal by a sound transducer often acts as an unpleasant noise, thus necessitating a paging signal by a vibration motor. The conventional flat type vibration motor uses three-phase windings with three phase coils. In this article, a new design of a vibration motor using a V connection with two phase coils is presented, increasing mass productivity. For electromagnetic field analysis, due to the motor symmetry, two-dimensional modeling can be implemented for fast computation, and performance is predicted by the finite element method. The winding distribution angle turns out to be the most important design parameter for the elimination of dead points, and a new coil configuration is suggested which has no adverse effect on motor size and weight. Experimental tests of vibration confirm the validity of the proposed design.

  2. 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)

  3. 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......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...

  4. Composite single crystal silicon scan mirror substrates, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Single crystal silicon is a desirable mirror substrate for scan mirrors in space telescopes. As diameters of mirrors become larger, existing manufacturing...

  5. 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

  6. Multiple Gas-Phase Conformations of a Synthetic Linear Poly(acrylamide) Polymer Observed Using Ion Mobility-Mass Spectrometry

    Science.gov (United States)

    Haler, Jean R. N.; Far, Johann; Aqil, Abdelhafid; Claereboudt, Jan; Tomczyk, Nick; Giles, Kevin; Jérôme, Christine; De Pauw, Edwin

    2017-08-01

    Ion mobility-mass spectrometry (IM-MS) has emerged as a powerful separation and identification tool to characterize synthetic polymer mixtures and topologies (linear, cyclic, star-shaped,…). Electrospray coupled to IM-MS already revealed the coexistence of several charge state-dependent conformations for a single charge state of biomolecules with strong intramolecular interactions, even when limited resolving power IM-MS instruments were used. For synthetic polymers, the sample's polydispersity allows the observation of several chain lengths. A unique collision cross-section (CCS) trend is usually observed when increasing the degree of polymerization (DP) at constant charge state, allowing the deciphering of different polymer topologies. In this paper, we report multiple coexisting CCS trends when increasing the DP at constant charge state for linear poly(acrylamide) PAAm in the gas phase. This is similar to observations on peptides and proteins. Biomolecules show in addition population changes when collisionally heating the ions. In the case of synthetic PAAm, fragmentation occurred before reaching the energy for conformation conversion. These observations, which were made on two different IM-MS instruments (SYNAPT G2 HDMS and high resolution multi-pass cyclic T-Wave prototype from Waters), limit the use of ion mobility for synthetic polymer topology interpretations to polymers where unique CCS values are observed for each DP at constant charge state. [Figure not available: see fulltext.

  7. The promise of mobile technologies and single case designs for the study of individuals in their natural environment.

    Science.gov (United States)

    Vilardaga, Roger; Bricker, Jonathan; McDonell, Michael

    2014-04-01

    Mobile technologies are growing rapidly around the world to broad demographics of society. These technologies hold great promise for their integration with Single Case Designs (SCDs) and the study of individuals in their natural environment. This paper discusses the theoretical, methodological and analytic implications of these tools for the advancement of the contextual behavioral etiology of behavioral disorders, and their remediation. We hope this paper will highlight the scientific advantages of combining mobile technologies and SCDs and encourage their adoption among CBS scientists.

  8. 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)

  9. 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.

  10. Analysis of phase-locked loop influence on the stability of single-phase grid-connected inverter

    DEFF Research Database (Denmark)

    Zhang, Chong; Wang, Xiongfei; Blaabjerg, Frede

    2015-01-01

    A controlled power inverter can cause instability at the point of common coupling (PCC) with its output filter and the grid. This paper analyzes the influence of the Phase-Locked Loop (PLL) on the output admittance of single-phase current-controlled inverters with different grid stiffness. It shows...

  11. Structure and magnetism of single-phase epitaxial gamma '-Fe4N

    NARCIS (Netherlands)

    Costa-Kramer, JL; Borsa, DM; Garcia-Martin, JM; Martin-Gonzalez, MS; Boerma, DO; Briones, F

    Single phase epitaxial pure gamma(')-Fe4N films are grown on MgO (001) by molecular beam epitaxy of iron in the presence of nitrogen obtained from a radio frequency atomic source. The epitaxial, single phase nature of the films is revealed by x-ray diffraction and by the local magnetic environment

  12. 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.

  13. 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....

  14. Gas-phase metalloprotein complexes interrogated by ion mobility-mass spectrometry

    Science.gov (United States)

    Faull, Peter A.; Korkeila, Karoliina E.; Kalapothakis, Jason M.; Gray, Andrew; McCullough, Bryan J.; Barran, Perdita E.

    2009-06-01

    Gas-phase biomolecular structure may be explored through a number of analytical techniques. Ion mobility-mass spectrometry (IM-MS) continues to prove itself as a sensitive and reliable bioanalytical tool for gas-phase structure determination due to intense study and development over the past 15 years. A vast amount of research interest, especially in protein and peptide conformational studies has generated a wealth of structural information for biological systems from small peptides to megadalton-sized biomolecules. In this work, linear low field IM-MS has been used to study gas-phase conformations and determine rotationally averaged collision cross-sections of three metalloproteins--cytochrome c, haemoglobin and calmodulin. Measurements have been performed on the MoQToF, a modified QToF 1 instrument (Micromass UK Ltd., Manchester, UK) modified in house. Gas-phase conformations and cross-sections of multimeric cytochrome c ions of the form [xM + nH+]n+ for x = 1-3 (monomer to trimer) have been successfully characterised and measured. We believe these to be the first reported collision cross-sections of higher order multimeric cytochrome c. Haemoglobin is investigated to obtain structural information on the associative mechanism of tetramer formation. Haemoglobin molecules, comprising apo- and holo-monomer chains, dimer and tetramer are transferred to the gas phase under a range of solution conditions. Structural information on the proposed critical intermediate, semi-haemoglobin, is reported. Cross-sections of the calcium binding protein calmodulin have been obtained under a range of calcium-bound conditions. Metalloprotein collision cross-sections from ion mobility measurements are compared with computationally derived values from published NMR and X-ray crystallography structural data. Finally we consider the change in the density of the experimentally measured rotationally averaged collision cross-section for compact geometries of the electrosprayed proteins.

  15. Tree Height Growth Measurement with Single-Scan Airborne, Static Terrestrial and Mobile Laser Scanning

    Directory of Open Access Journals (Sweden)

    Yi Lin

    2012-09-01

    Full Text Available This study explores the feasibility of applying single-scan airborne, static terrestrial and mobile laser scanning for improving the accuracy of tree height growth measurement. Specifically, compared to the traditional works on forest growth inventory with airborne laser scanning, two issues are regarded: “Can the new technique characterize the height growth for each individual tree?” and “Can this technique refine the minimum growth-discernable temporal interval further?” To solve these two puzzles, the sampling principles of the three laser scanning modes were first examined, and their error sources against the task of tree-top capturing were also analyzed. Next, the three-year growths of 58 Nordic maple trees (Crimson King for test were intermittently surveyed with one type of laser scanning each time and then analyzed by statistics. The evaluations show that the height growth of each individual tree still cannot be reliably characterized even by single-scan terrestrial laser scanning, and statistical analysis is necessary in this scenario. After Gaussian regression, it is found that the minimum temporal interval with distinguishable tree height growths can be refined into one month based on terrestrial laser scanning, far better than the two years deduced in the previous works based on airborne laser scanning. The associated mean growth was detected to be about 0.12 m. Moreover, the parameter of tree height generally under-estimated by airborne and even mobile laser scanning can be relatively revised by means of introducing static terrestrial laser scanning data. Overall, the effectiveness of the proposed technique is primarily validated.

  16. Mobilities

    DEFF Research Database (Denmark)

    will cover diverse topics such as theories, concepts, methods, and approaches as well as it will explore various modes of mobilities and the relationship to everyday life practices. The selection also covers the ‘politics of mobilities’ from local urban planning schemes to geopolitical issues of refugees...

  17. Single Crystal Bimorph Array Driven Deformable Mirrors, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research (SBIR) Phase I project will research a novel deformable mirror design for NASA adaptive optics telescope applications . The...

  18. 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.

  19. 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...

  20. 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...

  1. 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;...

  2. 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

  3. 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.

  4. 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....... The properties of the model are calculated by Monte Carlo computer-simulation techniques. The two temperatures and the external drive on the system lead to a rich phase diagram including regions of microstructured phases in addition to macroscopically ordered (phase-separated) and disordered phases. Depending...

  5. Trying to detect gas-phase ions? Understanding Ion Mobility Spectrometry

    Science.gov (United States)

    Cumeras, R.; Figueras, E.; Davis, C.E.; Baumbach, J.I.; Gràcia, I.

    2014-01-01

    Ion Mobility Spectrometry (IMS) is a widely used and ‘well-known’ technique of ion separation in gaseous phase based on the differences of ion mobilities under an electric field. This technique has received increased interest over the last several decades as evidenced by the pace and advances of new IMS devices available. In this review we explore the hyphenated techniques that are used with IMS, especially mass spectrometry as identification approach and multi-capillary column as pre-separation approach. Also, we will pay special attention to the key figures of merit of the ion mobility spectrum and how data is treated, and the influences of the experimental parameters in both a conventional drift time IMS (DTIMS) and a miniaturized IMS also known as high Field Asymmetric IMS (FAIMS) in the planar configuration. The current review article is preceded by a companion review article which details the current instrumentation and to the sections that configures both a conventional DTIMS and FAIMS devices. Those reviews will give the reader an insightful view of the main characteristics and aspects of the IMS technique. PMID:25465248

  6. A single-component liquid-phase hydrogen storage material.

    Science.gov (United States)

    Luo, Wei; Campbell, Patrick G; Zakharov, Lev N; Liu, Shih-Yuan

    2011-12-07

    The current state-of-the-art for hydrogen storage is compressed H(2) at 700 bar. The development of a liquid-phase hydrogen storage material has the potential to take advantage of the existing liquid-based distribution infrastructure. We describe a liquid-phase hydrogen storage material that is a liquid under ambient conditions (i.e., at 20 °C and 1 atm pressure), air- and moisture-stable, and recyclable; releases H(2) controllably and cleanly at temperatures below or at the proton exchange membrane fuel cell waste-heat temperature of 80 °C; utilizes catalysts that are cheap and abundant for H(2) desorption; features reasonable gravimetric and volumetric storage capacity; and does not undergo a phase change upon H(2) desorption. © 2011 American Chemical Society

  7. 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.)

  8. An Adaptive Quadrature Signal Generation Based Single-Phase Phase-Locked Loop for Grid-Connected Applications

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Abusorrah, Abdullah

    2017-01-01

    The quadrature signal generation based phase-locked loops (QSG-PLLs) are highly popular for synchronization purposes in single-phase systems. The main difference among these PLLs often lies in the technique they use for creating the fictitious quadrature component. One of the easiest QSG approaches...... is delaying the original single-phase signal by a quarter of a cycle. The PLL with such QSG technique is often called the transfer delay based PLL (TD-PLL). The TD-PLL benefits from a simple structure, rather fast dynamic response, and a good detection accuracy when the grid frequency is at its nominal value......, but it suffers from a phase offset error and double frequency oscillatory error in the estimated phase and frequency in the presence of frequency drifts. In this paper, a simple yet effective approach to remove the aforementioned errors of the TD-PLL is proposed. The resultant PLL structure is called...

  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. An Asymmetrical Space Vector Method for Single Phase Induction Motor

    DEFF Research Database (Denmark)

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

    2002-01-01

    the motor torque performance is not good enough. This paper addresses a new control method, an asymmetrical space vector method with PWM modulation, also a three-phase inverter is used for the main winding and the auxiliary winding. This method with PWM modulation is implemented to control the motor speed...

  11. Single-layer dual germanene phases on Ag(111)

    Science.gov (United States)

    Lin, Chung-Huang; Huang, Angus; Pai, Woei Wu; Chen, Wei-Chuan; Chen, Ting-Yu; Chang, Tay-Rong; Yukawa, Ryu; Cheng, Cheng-Maw; Mou, Chung-Yu; Matsuda, Iwao; Chiang, T.-C.; Jeng, H.-T.; Tang, S.-J.

    2018-02-01

    Two-dimensional (2D) honeycomb lattices beyond graphene promise new physical properties such as quantum spin Hall effect. While there have been claims of growth of such lattices (silicene, germanene, stanene), their existence needs further support and their preparation and characterization remain a difficult challenge. Our findings suggest that two distinct phases associated with germanene, the analog of graphene made of germanium (Ge) instead of carbon, can be grown on Ag(111) as observed by scanning tunneling microscopy, low-energy electron diffraction, and angle-resolved photoemission spectroscopy. One such germanene exhibits an atom-resolved alternatively buckled full honeycomb lattice, which is tensile strained and partially commensurate with the substrate to form a striped phase (SP). The other, a quasifreestanding phase (QP), is also consistent with a honeycomb lattice with a lattice constant incommensurate with the substrate but very close to the theoretical value for freestanding germanene. The SP, with a lower atomic density, can be driven into the QP and coexist with the QP by additional Ge deposition. Band mapping and first-principles calculations with proposed SP and QP models reveal an interface state exists only in the SP but the characteristic σ band of freestanding germanene emerges only in the QP—this leads to an important conclusion that adlayer-substrate commensurability plays a key role to affect the electronic structure of germanene. The evolution of the dual germanene phases manifests the competitive formation of Ge-Ge covalent and Ge-Ag interfacial bonds.

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

    Indian Academy of Sciences (India)

    during light load condition the excess energy generated from the PV inverter is fed to the grid and; during an overload condition or in case of unfavorable atmospheric conditions the load demand is met by both PV inverter and the grid. In order to synchronize the PV inverter with the grid a dual transport delay based phase ...

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

    Indian Academy of Sciences (India)

    Melo G and Canesin C A 2013 Evaluation of the main MPPT techniques for photovoltaic applications. IEEE Trans. Ind. Electron. 60(3): 1156–1167. [7] Jain S and Agarwal V 2007 Comparison of the perfor- mance of maximum power point tracking schemes applied to single-stage grid-connected photovoltaic systems.

  14. 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.

  15. Single-arm phase II trial design under parametric cure models.

    Science.gov (United States)

    Wu, Jianrong

    2015-01-01

    The current practice of designing single-arm phase II survival trials is limited under the exponential model. Trial design under the exponential model may not be appropriate when a portion of patients are cured. There is no literature available for designing single-arm phase II trials under the parametric cure model. In this paper, a test statistic is proposed, and a sample size formula is derived for designing single-arm phase II trials under a class of parametric cure models. Extensive simulations showed that the proposed test and sample size formula perform very well under different scenarios. Copyright © 2015 John Wiley & Sons, Ltd.

  16. 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.

  17. 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).

  18. Trying to detect gas-phase ions? Understanding Ion Mobility Spectrometry: Part 2: Hyphenated Methods and Effects of Experimental Parameters

    OpenAIRE

    Cumeras, R.; Figueras, E.; Davis, C.E.; Baumbach, J.I.; Gràcia, I.

    2015-01-01

    Ion Mobility Spectrometry (IMS) is a widely used and ‘well-known’ technique of ion separation in gaseous phase based on the differences of ion mobilities under an electric field. This technique has received increased interest over the last several decades as evidenced by the pace and advances of new IMS devices available. In this review we explore the hyphenated techniques that are used with IMS, especially mass spectrometry as identification approach and multi-capillary column as pre-separat...

  19. Single-Phase Direct Boost AC-AC Converter

    Directory of Open Access Journals (Sweden)

    URSARU, O.

    2017-11-01

    Full Text Available This paper introduces and studies a boost AC-AC converter circuit that can be used to supply power to the 220V receivers in the 110V grids or to increase and adjust voltage at the end of long lines. High frequency AC-AC converters have better specifications than alternative voltage phase control drives with thyristors or TRIACs. When frequency exceeds 20kHz, noise is eliminated, filters are smaller and efficiency is higher. The current waveform is much better, the output voltage can be higher than the input voltage and voltage control is more accurate.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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)

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

    Science.gov (United States)

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

    2016-09-01

    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.

  6. 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...... vectors. Simulation results show that the proposed approach lead to a lower THD in the injected current combined with fast dynamics. The proposed predictive control has been simulated and implemented on a 1 kW single-phase HERIC (highly efficient and reliable inverter concept) inverter with an LCL filter...

  7. High Energy Single Frequency Fiber Laser at Low Repetition Rate, 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...

  8. Tunable High-Power Single-Frequency Laser at 2050 nm, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a novel new architecture for a low-phase noise electronically tunable laser single-frequency laser at 2.05 microns that meets all the demanding...

  9. High Energy Single Frequency Fiber Laser at Low Repetition Rate, 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 operating at low repetition rate of 10 Hz to 1 kHz for coherent Lidar systems...

  10. Pulsed, Single-Frequency, 2-um Seed Source for Coherent LIDAR Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The primary objective of the proposed Phase I effort is to develop and demonstrate a low-average power, pulsed, single-frequency, 2-um Ho-laser source for...

  11. Light-Weight, Low-Cost, Single-Phase, Liquid-Cooled Cold Plate (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Narumanchi, S.

    2013-07-01

    This presentation, 'Light-Weight, Low-Cost, Single-Phase Liquid-Cooled Cold Plate,' directly addresses program goals of increased power density, specific power, and lower cost of power electronics components through improved thermal management.

  12. 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...

  13. 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.

  14. 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...

  15. 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...

  16. Gas-phase ion-mobility characterization of SAM-functionalized Au nanoparticles.

    Science.gov (United States)

    Tsai, D-H; Zangmeister, R A; Pease, L F; Tarlov, M J; Zachariah, M R

    2008-08-19

    We present results of a systematic examination of functionalized gold nanoparticles (Au-NPs) by electrospray-differential mobility analysis (ES-DMA). Commercially available, citrate-stabilized Au colloid solutions (10-60 nm) were sized using ES-DMA, from which changes in particle size of less than 0.3 nm were readily discerned. It was found that the formation of salt particles and the coating of Au-NPs by salt during the electrospray process can interfere with the mobility analysis, which required the development of sample preparation and data correction protocols to extract correct values for the Au-NP size. Formation of self-assembled monolayers (SAMs) of alkanethiol molecules on the Au-NP surface was detected from a change in particle mobility, which could be modeled to extract the surface packing density of SAMs. A gas-phase temperature-programmed desorption (TPD) kinetic study of SAMs on Au-NPs found the data to be consistent with a second-order Arrhenius-based rate law, yielding an Arrhenius factor of 1.0 x 10 (11) s (-1) and an activation energy approximately 105 kJ/mol. For the size range of SAM-modified Au-NP we considered, the effect of surface curvature on the energetics of binding of carboxylic acid terminated SAMs is evidently negligible, with binding energies determined by TPD agreeing with those reported for the same SAMs on planar surfaces. This study suggests that the ES-DMA can be added to the tool set of characterization methods used to study the structure and properties of coated nanoparticles.

  17. Direct single to two/three phase power electronic conversion for AC traction applications

    Energy Technology Data Exchange (ETDEWEB)

    Dobrucky, B.; Pavlanin, R.; Pokorny, M. [Zilina Univ. (Slovakia). Faculty of Electrical Engineering

    2008-07-01

    This paper discussed single to 3-phase power electronic converters. Conversion rates were evaluated using a middle frequency transformer with matrix converters. The use of a matrix converter subsystem with a 2-phase orthogonal induction motor was compared with conventional drives as a means of reducing the number of converter power switching elements. The converter was a high voltage modular multilevel converter where the transformer was fed directly by the single phase converter system operating on an AC line voltage. The converter offered sinusoidal input and output harmonics, eliminated the need for a DC link circuit, and decreased the number of switching elements for converters in AC-AC drives. A power active filter was used to improve the harmonic content of the input and output currents. Simulations of the 2-phase matrix converter orthogonal driving concept indicated that the converter can be used to provide solutions for single phase electric traction applications. 21 refs., 15 figs.

  18. 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.

  19. 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).

  20. 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.

  1. Performance of different C18 columns in reversed-phase liquid chromatography with hydro-organic and micellar-organic mobile phases.

    Science.gov (United States)

    Ruiz-Angel, M J; Pous-Torres, S; Carda-Broch, S; García-Alvarez-Coque, M C

    2014-05-30

    Column selection in reversed-phase liquid chromatography (RPLC) can become a challenge if the target compounds interact with the silica-based packing. One of such interactions is the attraction of cationic solutes to the free silanols in silica-based columns, which is a slow sorption-desorption interaction process that gives rise to tailed and broad peaks. The effect of silanols is minimised by the addition of a competing agent in the mobile phase, such as the anionic surfactant sodium dodecyl sulphate (SDS). In micellar-organic RPLC, the adsorption of an approximately fixed amount of SDS monomers gives rise to a stable modified stationary phase, with properties remarkably different from those of the underlying bonded phase. The chromatographic behaviour (in terms of selectivity, analysis time and peak shape) of eight C18 columns in the analysis of weakly acidic phenols and basic β-blockers was examined with hydro-organic and micellar-organic mobile phases. The behaviour of the columns differed significantly when the cationic basic drugs were eluted with hydro-organic mobile phases. With micellar-organic mobile phases, the adsorption of surfactant, instead of making the columns similar, gave rise to a greater diversity of behaviours (especially in terms of selectivity and analysis time), for both groups of phenols and β-blockers, which should be explained by the residual effect of the underlying bonded stationary phase and the different amount of surfactant covering the packing. Therefore, the implementation of a micellar-organic procedure in RPLC will depend significantly on the selected type of C18 column. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. 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)

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

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede

    2012-01-01

    under grid faults. The focus of this paper is put on the benchmarking of synchronization techniques, mainly about phase locked loop (PLL) based methods, in single-phase PV power systems operating under grid faults. Some faulty mode cases are studied at the end of this paper in order to compare...

  4. Preliminary experiments on phase conjugation for flow visualization. [barium titanate single crystals

    Science.gov (United States)

    Weimer, D.; Howes, W. L.

    1984-01-01

    Barium titanate single crystals are discussed in the context of: the procedure for polarizing a crystal; a test for phase conjugation; transients in the production of phase conjugation; real time readout by a separate laser of a hologram induced within the crystal, including conjugation response times to on-off switching of each beam; and a demonstration of a Twyman-Green interferometer utilizing phase conjugation.

  5. 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

    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...

  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. 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.

  8. Mask-based approach to phasing of single-particle diffraction data.

    Science.gov (United States)

    Lunin, Vladimir Y; Lunina, Natalia L; Petrova, Tatiana E; Baumstark, Manfred W; Urzhumtsev, Alexandre G

    2016-01-01

    A Monte Carlo-type approach for low- and medium-resolution phasing of single-particle diffraction data is suggested. Firstly, the single-particle phase problem is substituted with the phase problem for an imaginary crystal. A unit cell of this crystal contains a single isolated particle surrounded by a large volume of bulk solvent. The developed phasing procedure then generates a large number of connected and finite molecular masks, calculates their Fourier coefficients, selects the sets with magnitudes that are highly correlated with the experimental values and finally aligns the selected phase sets and calculates the averaged phase values. A test with the known structure of monomeric photosystem II resulted in phases that have 97% correlation with the exact phases in the full 25 Å resolution shell (1054 structure factors) and correlations of 99, 94, 81 and 79% for the resolution shells ∞-60, 60-40, 40-30 and 30-25 Å, respectively. The same procedure may be used for crystallographic ab initio phasing.

  9. Thickness-dependent electron mobility of single and few-layer MoS2 thin-film transistors

    Directory of Open Access Journals (Sweden)

    Ji Heon Kim

    2016-06-01

    Full Text Available We investigated the dependence of electron mobility on the thickness of MoS2 nanosheets by fabricating bottom-gate single and few-layer MoS2 thin-film transistors with SiO2 gate dielectrics and Au electrodes. All the fabricated MoS2 transistors showed on/off-current ratio of ∼107 and saturated output characteristics without high-k capping layers. As the MoS2 thickness increased from 1 to 6 layers, the field-effect mobility of the fabricated MoS2 transistors increased from ∼10 to ∼18 cm2V−1s−1. The increased subthreshold swing of the fabricated transistors with MoS2 thickness suggests that the increase of MoS2 mobility with thickness may be related to the dependence of the contact resistance and the dielectric constant of MoS2 layer on its thickness.

  10. Correlation between crystal structure and mobility in organic field-effect transistors based on single crystals of tetrathiafulvalene derivatives.

    Science.gov (United States)

    Mas-Torrent, Marta; Hadley, Peter; Bromley, Stefan T; Ribas, Xavi; Tarrés, Judit; Mas, Montserrat; Molins, Elies; Veciana, Jaume; Rovira, Concepció

    2004-07-14

    Recently, it was reported that crystals of the organic material dithiophene-tetrathiafulvalene (DT-TTF) have a high field-effect charge carrier mobility of 1.4 cm(2)/(V x s). These crystals were formed by a simple drop-casting method, making this material interesting to investigate for possible applications in low-cost electronics. Here, organic single-crystal field-effect transistors based on materials related to DT-TTF are presented and a clear correlation between the crystal structure and the electrical characteristics is observed. The observed relationship between the mobilities in the different crystal structures is strongly corroborated by calculations of both the molecular reorganization energies and the maximum intermolecular transfer integrals. The most suitable materials described here exhibit mobilities that are among the highest reported for organic field-effect transistors and that are the highest reported for solution-processed materials.

  11. Stability boundary analysis in single-phase grid-connected inverters with PLL by LTP theory

    OpenAIRE

    Salis, Valerio; Costabeber, Alessando; Cox, Stephen M.; Zanchetta, Pericle; Formentini, Andrea

    2017-01-01

    Stability analysis of power converters in AC net¬works is complex due to the non-linear nature of the conversion systems. Whereas interactions of converters in DC networks can be studied by linearising about the operating point, the extension of the same approach to AC systems poses serious challenges, especially for single-phase or unbalanced three-phase systems. A general method for stability analysis of power converters suitable for single-phase or unbalanced AC networks is presented in th...

  12. 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...

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. Coordinated control of tethered space robot using mobile tether attachment point in approaching phase

    Science.gov (United States)

    Wang, Dongke; Huang, Panfeng; Cai, Jia; Meng, Zhongjie

    2014-09-01

    Tethered space robots (TSRs) have wide applications in future on-orbit service owing to its flexibility and great workspace. However, the control problem is quite complex and difficult in the phase of approaching target, and the fuel consumption must also be taken into account. Hence, we present a novel scheme of achieving coordinated orbit and attitude control simultaneously for the TSR. Space tether, which can provide greater force compared with the thruster force, is used in the design of the orbit and attitude coordinated controller. A coordinated control mechanism is designed to provide attitude control torques of the pitch and yaw motions by adjusting the position of the mobile tether attachment point, while the roll motion is stabilized by the thruster. In order to guarantee this mechanism to work properly, constant tether tension strategies are utilized to plan an optimal approaching trajectory which is tracked by the coordinated controller of tether force and thruster force. Numerical simulation validates the feasibility of our proposed coordinated control scheme for TSR in the approaching phase. Furthermore, fuel consumption of the orbit and attitude control are both significantly reduced compared with traditional thruster control.

  18. Fast detection of narcotics by single photon ionization mass spectrometry and laser ion mobility spectrometry

    Science.gov (United States)

    Laudien, Robert; Schultze, Rainer; Wieser, Jochen

    2010-10-01

    In this contribution two analytical devices for the fast detection of security-relevant substances like narcotics and explosives are presented. One system is based on an ion trap mass spectrometer (ITMS) with single photon ionization (SPI). This soft ionization technique, unlike electron impact ionization (EI), reduces unwanted fragment ions in the mass spectra allowing the clear determination of characteristic (usually molecular) ions. Their enrichment in the ion trap and identification by tandem MS investigations (MS/MS) enables the detection of the target substances in complex matrices at low concentrations without time-consuming sample preparation. For SPI an electron beam pumped excimer light source of own fabrication (E-Lux) is used. The SPI-ITMS system was characterized by the analytical study of different drugs like cannabis, heroin, cocaine, amphetamines, and some precursors. Additionally, it was successfully tested on-site in a closed illegal drug laboratory, where low quantities of MDMA could be directly detected in samples from floors, walls and lab equipments. The second analytical system is based on an ion mobility (IM) spectrometer with resonant multiphoton ionization (REMPI). With the frequency quadrupled Nd:YAG laser (266 nm), used for ionization, a selective and sensitive detection of aromatic compounds is possible. By application of suited aromatic dopants, in addition, also non-aromatic polar compounds are accessible by ion molecule reactions like proton transfer or complex formation. Selected drug precursors could be successfully detected with this device as well, qualifying it to a lower-priced alternative or useful supplement of the SPI-ITMS system for security analysis.

  19. Ion beam induced single phase nanocrystalline TiO2 formation

    Science.gov (United States)

    Rukade, Deepti A.; Tribedi, L. C.; Bhattacharyya, Varsha

    2014-06-01

    Single phase TiO2 nanostructures are fabricated by oxygen ion implantation (60 keV) at fluence ranging from 1×1016 ions/cm2 to 1×1017 ions/cm2 in titanium thin films deposited on fused silica substrate and subsequent thermal annealing in argon atmosphere. GAXRD and Raman spectroscopy study reveals formation of single rutile phases of TiO2. Particle size is found to vary from 29 nm to 35 nm, establishing nanostructure formation. Nanostructure formation is also confirmed by the quantum confinement effect manifested by the blueshift of the UV-vis absorption spectra. Photoluminescence spectra show peaks corresponding to TiO2 rutile phase and reveal the presence of oxygen defects due to implantation. The controlled synthesis of single phase nanostructure is attributed to ion induced defects and post-implantation annealing. It is observed that the size of the nanostructures formed is strongly dependent on the ion fluence.

  20. 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...... of simple configuration, low-cost, low-profile, and easy fabrication. Simulations have been done to validate the feasibility of the proposed phased array antenna for MSAT applications....

  1. 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.

  2. Phase transitions and optical properties of the semiconducting and metallic phases of single-layer MoS₂.

    Science.gov (United States)

    Fair, K M; Ford, M J

    2015-10-30

    We report density functional theory calculations for single layer MoS2 in its 2H, semiconducting and 1T metallic phases in order to understand the relative stability of these two phases and transition between them in the presence of adsorbed lithium atoms and under compressive strain. We have determined the diffusion barriers between the two phases and demonstrate how the presence of Li adatoms or strain can significantly reduce these barriers. We show that the 2H and 1T structures have the same energy under 15% biaxial, compressive strain. This is the same strain value posited by Lin et al (2014 Nat. Nanotechnology 9 391-396) for their intermediate α phase. Calculations of the 1T and 2H permittivity and electron energy loss spectrum are also performed and characterized.

  3. 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.

  4. 77 FR 32092 - Mobility Fund Phase I Auction Scheduled for September 27, 2012; Notice and Filing Requirements...

    Science.gov (United States)

    2012-05-31

    ... Bureaus used geographic information system (GIS) software to determine whether the American Roamer data... information system (GIS) data for the census blocks eligible for Mobility Fund Phase I support to be offered... typically connect to highways and other types of roads, and private roads that are used in areas with...

  5. Enhanced extraction yields and mobile phase separations by solvent mixtures for the analysis of metabolites in Annona muricata L. leaves.

    Science.gov (United States)

    Ribeiro de Souza, Eloana Benassi; da Silva, Renata Reis; Afonso, Sabrina; Scarminio, Ieda Spacino

    2009-12-01

    The effects of five extraction solvents and their mixtures on the yield of metabolites in crude and fractionated extracts of Annona muricata L. leaves were investigated by direct comparison. Extraction media were prepared using simplex centroid mixtures of ethanol, ethyl acetate, dichloromethane, acetone, and chloroform. The effects of the mobile phase solvent strength and the analysis wavelength on the chromatographic separation were also investigated. Solvent mixtures rather than pure solvents were found to be the most efficient extractors for the different fractions. The results indicated that the mobile phase composed of methanol/acetonitrile/water (26:27:47 v/v/v) was most suitable for the basic fraction analysis at 254 nm, whereas the mobile phase composed of methanol/acetonitrile/water (35:35:30 v/v/v) was the most adequate for the organic fraction analysis at 254 nm. The results indicated that the chromatographic profiles and number of peaks were affected by the mobile phase strength and analysis wavelength.

  6. Quinine-Based Zwitterionic Chiral Stationary Phase as a Complementary Tool for Peptide Analysis: Mobile Phase Effects on Enantio- and Stereoselectivity of Underivatized Oligopeptides.

    Science.gov (United States)

    Ianni, Federica; Sardella, Roccaldo; Carotti, Andrea; Natalini, Benedetto; Lindner, Wolfgang; Lämmerhofer, Michael

    2016-01-01

    Peptide stereoisomer analysis is of importance for quality control of therapeutic peptides, the analysis of stereochemical integrity of bioactive peptides in food, and the elucidation of the stereochemistry of peptides from a natural chiral pool which often contains one or more D-amino acid residues. In this work, a series of model peptide stereoisomers (enantiomers and diastereomers) were analyzed on a zwitterionic ion-exchanger chiral stationary phase (Chiralpak ZWIX(+) 5 µm), in order to investigate the retention and separation performance for such compounds on this chiral stationary phase and elucidate its utility for this purpose. The goal of the study focused on 1) investigations of the effects of the sample matrix used to dissolve the peptide samples; 2) optimization of the mobile phase (enabling deriving information on factors of relevance for retention and separation); and 3) derivation of structure-selectivity relationships. It turned out that small di- and tripeptides can be well resolved under optimized conditions, typically with resolutions larger than 1.5. The optimized mobile phase often consisted of methanol-tetrahydrofuran-water (49:49:2; v/v/v) with 25 mM formic acid and 12.5 mM diethylamine. This work proposes some guidance on which mobile phases can be most efficiently used for peptide stereoisomer separations on Chiralpak ZWIX. Chirality 28:5-16, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  7. Single-shot X-ray phase-contrast imaging using two-dimensional gratings

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Genta; Itoh, Hidenosuke; Nagai, Kentaro; Nakamura, Takashi; Yamaguchi, Kimiaki; Kondoh, Takeshi; Handa, Soichiro; Ouchi, Chidane; Teshima, Takayuki; Setomoto, Yutaka; Den, Toru [Frontier Research Center, Corporate R and D Headquarters, Canon Inc., 3-30-2 Shimomaruko, Ohta-ku, Tokyo 146-8501 (Japan); Optics Technology Development Center, Corporate R and D Headquarters, Canon Inc., 23-10, Kiyohara-Kogyodanchi, Utsunomiya Tochigi 321-3231 (Japan); Nanotechnology R and D Center, Corporate R and D Headquarters, Canon Inc., 3-30-2 Shimomaruko, Ohta-ku, Tokyo 146-8501 (Japan)

    2012-07-31

    We developed a two-dimensional gratings-based X-ray interferometer that requires only a single exposure for clinical radiography. The interferometer consisted of a checkerboard phase grating for {pi} phase modulation and a latticed amplitude grating. Using a synchrotron radiation source, the phase grating modulates the X-rays and generates a self-image, transformed to a moire fringe by the amplitude grating. To allow use of a conventional X-ray tube, the latticed source grating was installed downstream from the X-ray tube. Differential phase-contrast and scattering images in two orthogonal directions were obtained by Fourier analysis of the single moire fringe image and an absorption image. Results show that characteristic features of soft tissue in two orthogonal directions were clearly shown in the differential phase-contrast images.

  8. 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

  9. 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.

  10. 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...

  11. Hard Upper Torso Shoulder Joint Design for Crew Member Sizing Adjustment and Enhanced Mobility, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Air-Lock, Incorporated proposes to design an Enhanced Shoulder Mobility Joint Assembly (ESMJA) that increases dynamic mobility and static sizing capabilities for...

  12. Innovation design of beta test loop system for heat transfer experiments in single-phase and two-phase flows

    International Nuclear Information System (INIS)

    Kiswanta; Edy Sumarno; Joko Prasetio W; Ainur Rosidi; G B Heru K

    2013-01-01

    Innovation design of BETA test loop has been done. BETA test loop is a research facility used as a support for experiments of reactor accident simulation. The innovation was performed to prepare experimental facilities in order to study flow of heat transfer in single-phase and two-phase flows. The design was executed by modifying new piping of UUB's primary system, addition of heat flux measurements and imaging thermal for easiness of experimental result analysis. UUB development and experiments were carried out to understand heat transfer process in the narrow gap of two-phase flow considering this phenomenon is one of the conditions postulated in PWR typed nuclear power plant accident scenario. The innovation design of BETA test loop is still in the planning stages so that the design has not been constructed. Piping systems made of SS-304 with the ability to use a maximum pressure of 10 bar with a diameter of % inch pipe to, from the calculation of minimal design that is 7.27 mm. If the tube SS-304 - ASTM B88 is the wall thickness of 0.083 inches. From this design it is indicated that the design is able to be fabricated and used for experimental study of heat transfer in single-phase and two-phase flows. (author)

  13. 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.)

  14. Scalable WDM phase regeneration in a single phase-sensitive amplifier through optical time lenses

    DEFF Research Database (Denmark)

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

    2018-01-01

    elusive, constituting a key challenge, which must be overcome for optical regeneration to have any prospect of being adapted in actual communication systems. Here we report a scalable wavelength-division multiplexing (WDM) regeneration scheme for phase only regeneration, which satisfies the multichannel...

  15. 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.

  16. Current Status of Single-Agent Phase I Trials in Japan: Toward Globalization.

    Science.gov (United States)

    Mizugaki, Hidenori; Yamamoto, Noboru; Fujiwara, Yutaka; Nokihara, Hiroshi; Yamada, Yasuhide; Tamura, Tomohide

    2015-06-20

    In Japan, phase I trials, except first-in-human trials, are usually initiated from approximately 50% of the maximum-tolerated dose (MTD) or maximum administered dose (MAD) determined during the initial phase I trials in North America and Europe (the West). However, the key findings of phase I trials in Japan and the West, such as dose-limiting toxicity (DLT) profiles and MTD or MAD levels, have not been compared. We retrospectively analyzed data for patients enrolled onto single-agent phase I trials at the National Cancer Center Hospital between 1995 and 2012. DLT profiles, MTDs, and MADs of single-agent phase I trials in Japan were compared with those from trials in the West that were obtained from the literature. A total of 777 patients were enrolled onto 54 single-agent phase I trials, including five first-in-human trials. DLTs were observed in 11.1% of the patients. Importantly, 66.4% of the DLTs were observed within a dose range (80% to 120%) similar to those reported for the trials in the West. The majority of MTDs or MADs could be considered similar between patients, and 80.3% of the drugs had similar MTDs or MADs in the West. The toxicity profiles of single-agent phase I agents determined from trials conducted in Japan were comparable to those obtained from trials in the West. We believe that phase I trials in Japan could be conducted over timelines similar to those in the West, allowing for global or parallel phase I clinical trials. © 2015 by American Society of Clinical Oncology.

  17. Solid phase epitaxial growth of high mobility La:BaSnO3 thin films co-doped with interstitial hydrogen

    Science.gov (United States)

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

    2016-04-01

    This work presents the solid phase epitaxial growth of high mobility La:BaSnO3 thin films on SrTiO3 single crystal substrates by crystallization through thermal annealing of nanocrystalline thin films prepared by pulsed laser deposition at room temperature. The La:BaSnO3 thin films show high epitaxial quality and Hall mobilities up to 26 ± 1 cm2/Vs. Secondary ion mass spectroscopy is used to determine the La concentration profile in the La:BaSnO3 thin films, and a 9%-16% La doping activation efficiency is obtained. An investigation of H doping to BaSnO3 thin films is presented employing H plasma treatment at room temperature. Carrier concentrations in previously insulating BaSnO3 thin films were increased to 3 × 1019 cm-3 and in La:BaSnO3 thin films from 6 × 1019 cm-3 to 1.5 × 1020 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):BaSnO3 electron effective mass of 0.27 ± 0.05 m0 and an optical mobility of 26 ± 7 cm2/Vs. As compared to La:BaSnO3 single crystals, the smaller electron mobility in epitaxial thin films grown on SrTiO3 substrates is ascribed to threading dislocations as observed in high resolution transmission electron micrographs.

  18. The Influence of phase-locked loop on the stability of single-phase grid-connected inverter

    DEFF Research Database (Denmark)

    Zhang, Chong; Wang, Xiongfei; Blaabjerg, Frede

    2015-01-01

    admittance of single-phase current-controlled inverters with different grid stiffness is analyzed in this paper. It shows that the PLL introduces a negative paralleled admittance into the output admittance of the inverter, which may lead to unintentional low-order harmonic oscillation in a weak grid...... for avoiding the PLL induced instability in single-phase inverters. At last the relationship between PLL bandwidth and the Short Circuit Ratio (SCR) of the grid has been derived to guide the design of the PLL. Experimental results are presented in order to verify this analysis, and the resonant frequencies can...... be predicted by the method. The possible instability due to different PLL bandwidth is also demonstrated....

  19. 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

    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...... 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....

  20. Field-circuit analysis and measurements of a single-phase self-excited induction generator

    Science.gov (United States)

    Makowski, Krzysztof; Leicht, Aleksander

    2017-12-01

    The paper deals with a single-phase induction machine operating as a stand-alone self-excited single-phase induction generator for generation of electrical energy from renewable energy sources. By changing number of turns and size of wires in the auxiliary stator winding, an improvement of performance characteristics of the generator were obtained as regards no-load and load voltage of the stator windings as well as stator winding currents of the generator. Field-circuit simulation models of the generator were developed using Flux2D software package for the generator with shunt capacitor in the main stator winding. The obtained results have been validated experimentally at the laboratory setup using the single-phase capacitor induction motor of 1.1 kW rated power and 230 V voltage as a base model of the generator.

  1. 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...... capability. The control methods, together with grid synchronization techniques, are responsible for the generation of appropriate reference signals in order to handle ride-through grid faults. Thus, it is necessary to evaluate the behaviors of grid synchronization methods and control possibilities in single...... 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 detection and control strategies are discussed. Some faulty modes are studied experimentally...

  2. 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.

  3. 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)

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

    Science.gov (United States)

    Hasegawa, Shin-ya; Hirata, Ryo

    2018-02-01

    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.

  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. Development of optimized mobile phases for protein separation by high performance thin layer chromatography.

    Science.gov (United States)

    Biller, Julia; Morschheuser, Lena; Riedner, Maria; Rohn, Sascha

    2015-10-09

    In recent years, protein chemistry tends inexorably toward the analysis of more complex proteins, proteoforms, and posttranslational protein modifications. Although mass spectrometry developed quite fast correspondingly, sample preparation and separation of these analytes is still a major issue and quite challenging. For many years, electrophoresis seemed to be the method of choice; nonetheless its variance is limited to parameters such as size and charge. When taking a look at traditional (thin-layer) chromatography, further parameters such as polarity and different mobile and stationary phases can be utilized. Further, possibilities of detection are manifold compared to electrophoresis. Similarly, two-dimensional separation can be also performed with thin-layer chromatography (TLC). As the revival of TLC developed enormously in the last decade, it seems to be also an alternative to use high performance thin-layer chromatography (HPTLC) for the separation of proteins. The aim of this study was to establish an HPTLC separation system that allows a separation of protein mixtures over a broad polarity range, or if necessary allowing to modify the separation with only few steps to improve the separation for a specific scope. Several layers and solvent systems have been evaluated to reach a fully utilized and optimized separation system. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. The Application Three-phase to Single-phase Z-Source Matrix Converter in Wind Turbine

    Directory of Open Access Journals (Sweden)

    vahid asadi rad

    2017-01-01

    Full Text Available In this paper a new idea of direct three-phase to single-phase Z-source matrix converter (impedance-source matrix converter applicable in stand-alone wind turbine is introduced. In the direct Z-source matrix converter amplitude of output voltage and frequency regulation are of importance to control system. In wind turbines, input voltage and frequency are usually changing due to wind speed variation that these alterations could be easily regulated by means of a direct Z-source matrix converter. A scheme is also offered to control the proposed direct three-phase to single-phase Z-source matrix converter. the control strategy would be able to adjust the output voltage and frequency at desired value as well as producing low THD (total harmonic distortion at the output voltage. The proposed structure and the control methodology are simulated using matlab simulink software and results are investigated and discussed to confirm the performance of the direct Z-source matrix converter in wind turbine.

  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. Single-carrier phase-disposition PWM implementation for multilevel flying capacitor converters

    OpenAIRE

    Ghias, Amer M.Y.M; Pou Félix, Josep; Capellá Frau, Gabriel José; Agelidis, Vassilios; Aguilera, Ricardo P; Meynard, Thierry A.

    2015-01-01

    This letter proposes a new implementation of phase-disposition pulse-width modulation (PD-PWM) for multilevel flying capacitor (FC) converters using a single triangular carrier. The proposed implementation is much simpler than conventional PD-PWM techniques based on multiple trapezoidal-shaped carriers, generates the same results as far as natural capacitor voltage balance is concerned and offers better quality line-to-line voltages when compared to phase-shifted PWM. The proposed algorithm i...

  12. A re-look at critical factors influencing single-phase formation of Ba2 ...

    Indian Academy of Sciences (India)

    TECS

    BaSnO3, B2O3 etc, single-phase 2: 9 has been achieved through solid-state route (Yu et al 1994; Lin and Robert. 1999; Wang et al 2003). It is recorded in literature that phase pure 2:9 ceramics without any stabilizing agent will result in better material for microwave dielectric applica- tions (Lin et al 1997; Lin and Robert ...

  13. Single-phase power distribution system power flow and fault analysis

    Science.gov (United States)

    Halpin, S. M.; Grigsby, L. L.

    1992-01-01

    Alternative methods for power flow and fault analysis of single-phase distribution systems are presented. The algorithms for both power flow and fault analysis utilize a generalized approach to network modeling. The generalized admittance matrix, formed using elements of linear graph theory, is an accurate network model for all possible single-phase network configurations. Unlike the standard nodal admittance matrix formulation algorithms, the generalized approach uses generalized component models for the transmission line and transformer. The standard assumption of a common node voltage reference point is not required to construct the generalized admittance matrix. Therefore, truly accurate simulation results can be obtained for networks that cannot be modeled using traditional techniques.

  14. Common-Ground-Type Tansformerless 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...

  15. 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.

  16. Referential ZMP Trajectory for Minimizing Variation of COG Velocity in Single Support Phase of Biped Robot

    Science.gov (United States)

    Sato, Tomoya; Ohnishi, Kouhei

    The referential ZMP (Zero-Moment Point) trajectory that minimizes the variation of COG (Center of Gravity) velocity in the single support phase of a biped robot is shown. Two advantages of using this ZMP trajectory are discussed. The first advantage is that the variation of COG velocity is gradual. The second advantage is that the biped robot enables the heel-contact motion and the toe-off motion in the single support phase. The trajectory planning based on this ZMP trajectory is proposed. In simulation and experiment, the validity of the proposed method was confirmed.

  17. Soft-Switched Neutral-Point-Clamped Single-Phase Boost Rectifier

    Science.gov (United States)

    Itoh, Ryozo; Ishizaka, Kouichi

    A soft-switched neutral-point-clamped single-phase boost rectifier capable of compensating the imbalance load voltage is studied. This is based on a single-phase rectifier, in which an inductor is placed in series with the AC supply to resonate with a capacitor connected across the DC output of a full-bridge rectifier and the switching transition is mainly governed by a series resonance. The experimental prototype using insulated-gate bipolar transistors is implemented to investigate the operation under the charge control. The experimental results confirm that the rectifier has a neutral-point-clamp feature providing a good quality AC current.

  18. Estimates of aqueous-phase sulfate production from tandem differential mobility analysis

    Science.gov (United States)

    Santarpia, Joshua L.; Collins, Don R.; Hegg, Dean A.; Kaku, Kathleen C.; Covert, David S.; Jonsson, Haflidi; Buzorius, Gintautas

    2011-10-01

    During June and July of 2004, airborne measurements of size-resolved aerosol properties were made over the coastal Pacific near Marina, California. Tandem differential mobility analysis was used to determine the hygroscopic properties of these aerosols and, subsequently, to examine the change in soluble mass after the aerosol had been cloud-processed. Three of the eight cases analyzed during the field campaign exhibited increased soluble mass attributable to cloud-processing. The calculated change in soluble mass after cloud-processing, derived from measurements made below and above cloud, ranged from 1.08 ϒ g m -3 to 1.40 ϒ g m -3. These values are in agreement with those determined using data collected during previous field studies in the same region. Aerosol size distributions measured throughout the study with a Passive Cavity Aerosol Spectrometer Probe were averaged to create a single representative distribution, which was used to examine the impact of the addition of sulfate to a typical aerosol measured during this project. Mass light-scattering efficiencies were calculated for both the initial and cloud-processed size distributions using Mie-Lorenz theory. These calculations show that the increase in mass light-scattering efficiency following passage through a single non-precipitating cloud to be 14%, which is in agreement with findings of previous studies in the same region. This new technique produces results that are consistent with existing methods for measuring in-cloud sulfate production and has the advantage of intrinsic consistency with the hygroscopicity and CCN activity of the aerosol.

  19. 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.

  20. 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.

  1. [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.

  2. Estimation of phase derivative from a single fringe pattern using Riesz transforms

    Science.gov (United States)

    Tounsi, Yassine; Zada, Sara; Muhire, Desire; Siari, Ahmed; Nassim, Abdelkrim

    2017-11-01

    We propose a technique to estimate the phase derivative in both x and y directions based on Riesz transform from a single speckle correlation fringes. The originality of this technique is to exploit Riesz transform for phase derivatives estimation, spatial modulation, speckle denoising, and measure of features similarity. Phase modulation process is realized by combining a digital spatial carrier and Riesz quadrature; speckle denoising is computed using Riesz wavelets transform, and the performance is evaluated by Riesz features SIMilarity. Before applying our method on real speckle correlation fringes, its performance is tested by numerical simulation.

  3. 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 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...

  4. 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)

  5. 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...

  6. 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...

  7. 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....

  8. Stabilization of gas-phase uranyl complexes enables rapid speciation using electrospray ionization and ion mobility-mass spectrometry.

    Science.gov (United States)

    Davis, Austen L; Clowers, Brian H

    2018-01-01

    Significant challenges exist when characterizing f-element complexes in solution using traditional approaches such as electrochemical and spectroscopic techniques as they do not always capture information for lower abundance species. However, provided a metal-complex with sufficient stability, soft ionization techniques such as electrospray offer a means to quantify and probe the characteristics of such systems using mass spectrometry. Unfortunately, the gas-phase species observed in ESI-MS systems do not always reflect the solution phase distributions due to the inherent electrochemical mechanism of the electrospray process, ion transfer from ambient to low pressures conditions, and other factors that are related to droplet evaporation. Even for simple systems (e.g. hydrated cations), it is not always clear whether the distribution observed reflects the solution phase populations or whether it is simply a result of the ionization process. This complexity is further compounded in mixed solvent systems and when multiply charged species are present. Despite these challenges, the benefits of mass spectrometry with respect to speed, sensitivity, and the ability to resolve isotopes continue to drive efforts to develop techniques for the speciation of metal complexes. Using an electrospray ionization atmospheric pressure ion mobility mass spectrometer (ESI-apIMS-MS), we demonstrate an approach to stabilize simple uranyl complexes during the ionization process and mobility separation to aid speciation and isotope profile analysis. Specifically, we outline and demonstrate the capacity of ESI-apIMS-MS methods to measure mobilities of different uranyl species, in simple mixtures, by promoting stable gas phase conformations with the addition of sulfoxides (i.e. dimethyl sulfoxide (DMSO), dibutyl sulfoxide (DBSO), and methyl phenyl sulfoxide (MPSO)). Addition of these sulfoxides, as observed in the mass spectrum and mobility domain, produce stable gas-phase conformations that

  9. 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.

  10. 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

  11. 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...

  12. Low Voltage Ride-Through of Single-Phase Transformerless Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Wang, Huai

    2014-01-01

    , e.g. Low Voltage Ride-Through (LVRT) under grid faults and grid support service. In order to map future challenges, the LVRT capability of three mainstream single-phase transformerless PV inverters under grid faults are explored in this paper. Control strategies with reactive power injections...

  13. 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.

  14. 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...

  15. 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%

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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 H...

  1. 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...

  2. 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...

  3. A re-look at critical factors influencing single-phase formation of Ba2 ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 30; Issue 4. A re-look at critical factors influencing single-phase formation of Ba2Ti9O20 microwave dielectrics. Unnikrishnan Gopinath Dhanya Chandran Seema Ansari Bindu Krishnan Rani Panicker Raghu Natarajan. Electrical Properties Volume 30 Issue 4 August ...

  4. Analysis of Variable-Speed Operation of Drives with Single-Phase Machines

    Czech Academy of Sciences Publication Activity Database

    Chomát, Miroslav; Schreier, Luděk; Bendl, Jiří

    2007-01-01

    Roč. 52, č. 2 (2007), s. 139-147 ISSN 0001-7043 R&D Projects: GA ČR GA102/06/0215 Institutional research plan: CEZ:AV0Z20570509 Keywords : single-phase machines * induction machines * variable-speed drives Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  5. Single-plane multiple speckle pattern phase retrieval using a deformable mirror

    DEFF Research Database (Denmark)

    Almoro, Percival F.; Glückstad, Jesper; Hanson, Steen Grüner

    2010-01-01

    A design for a single-plane multiple speckle pattern phase retrieval technique using a deformable mirror (DM) is analyzed within the formalism of complex ABCD-matrices, facilitating its use in conjunction with dynamic wavefronts. The variable focal length DM positioned at a Fourier plane of a lens...

  6. 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...

  7. 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 cont......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......-connected single-stage single-phase PV systems in the case of Low/Zero Voltage Ride-Through (LVRT/ZVRT) operation. A comparative analysis of the two LVRT/ZVRT control methods for PV systems is presented. Simulation results are presented, which verifies that the LVRT/ZVRT methods can help the PV systems...... to temporarily ride-through the grid low-/zero-voltage faults. The power phase-angle control method has a better dynamic response....

  8. 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.

  9. 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.

  10. Mixed response and time-to-event endpoints for multistage single-arm phase II design.

    Science.gov (United States)

    Lai, Xin; Zee, Benny Chung-Ying

    2015-06-04

    The objective of phase II cancer clinical trials is to determine if a treatment has sufficient activity to warrant further study. The efficiency of a conventional phase II trial design has been the object of considerable debate, particularly when the study regimen is characteristically cytostatic. At the time of development of a phase II cancer trial, we accumulated clinical experience regarding the time to progression (TTP) for similar classes of drugs and for standard therapy. By considering the time to event (TTE) in addition to the tumor response endpoint, a mixed-endpoint phase II design may increase the efficiency and ability of selecting promising cytotoxic and cytostatic agents for further development. We proposed a single-arm phase II trial design by extending the Zee multinomial method to fully use mixed endpoints with tumor response and the TTE. In this design, the dependence between the probability of response and the TTE outcome is modeled through a Gaussian copula. Given the type I and type II errors and the hypothesis as defined by the response rate (RR) and median TTE, such as median TTP, the decision rules for a two-stage phase II trial design can be generated. We demonstrated through simulation that the proposed design has a smaller expected sample size and higher early stopping probability under the null hypothesis than designs based on a single-response endpoint or a single TTE endpoint. The proposed design is more efficient for screening new cytotoxic or cytostatic agents and less likely to miss an effective agent than the alternative single-arm design.

  11. Doping-controlled phase transitions in single-layer MoS2

    Science.gov (United States)

    Zhuang, Houlong L.; Johannes, Michelle D.; Singh, Arunima K.; Hennig, Richard G.

    2017-10-01

    The electronic properties of single-layer MoS2 make it an ideal two-dimensional (2D) material for application in electronic devices. Experiments show that MoS2 can undergo structural phase transitions. Applications of single-layer MoS2 will require firm laboratory control over the phase formation. Here we compare the stability and electronic structure of the three experimentally observed single-layer MoS2 phases, 2 H ,1 T , and 1 T' , and an in-plane metal/semiconductor heterostructure. We reveal by density-functional theory calculations that charge doping can induce the phase transition of single-layer MoS2 from the 2 H to the 1 T structure. Further, the 1 T structure undergoes a second phase transition due to the occurrence of a charge-density wave (CDW). By comparing the energies of several possible resulting CDW structures, we find that the 1 T' orthorhombic structure is the most stable one, consistent with experimental observations and previous theoretical studies. We show that the underlying CDW transition mechanism is not due to Fermi surface nesting, but nonetheless, can be controlled by charge doping. In addition, the stability landscape is highly sensitive to charge doping, which can be used as a practical phase selector. We also provide a prescription for obtaining the 1 T' structure via growth or deposition of MoS2 on a Hf substrate, which transfers electrons uniformly and with minimal structural distortion. Finally, we show that lateral heterostructures formed by the 2 H and 1 T' structures exhibit a low interfacial energy of 0.17 eV/Å, a small Schottky barrier of 0.3 eV for holes, and a large barrier of 1.6 eV for electrons.

  12. Chirality-Controlled Growth of Single-Wall Carbon Nanotubes Using Vapor Phase Epitaxy: Mechanistic Understanding and Scalable Production

    Science.gov (United States)

    2016-09-15

    AFRL-AFOSR-VA-TR-2016-0319 Chirality-Controlled Growth of Single -Wall Carbon Nanotubes Using Vapor Phase Epitaxy: Mechanistic Understanding and...controlled growth of single -wall carbon nanotubes using vapor phase epitaxy: mechanistic understanding and scalable production FA9550-14-1-0115 Zhou...controlled synthesis of single -wall carbon nanotubes. Firstly, we have successfully demonstrated a vapor-phase-epitaxy-analogous general strategy for

  13. 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...... their beams to three distinct regions. Each subarray works as a phased array to steer the beam within each region. Large coverage efficiency is achieved (e.g., 80% of the space sphere has the realized gain of over 8 dBi). The proposed antenna covers a bandwidth of over 2 GHz in the band of 28 GHz. User...

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

    Energy Technology Data Exchange (ETDEWEB)

    Stassi, D.; Ma, H.; Schmidt, T. G., E-mail: taly.gilat-schmidt@marquette.edu [Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin 53201 (United States); Dutta, S.; Soderman, A.; Pazzani, D.; Gros, E.; Okerlund, D. [GE Healthcare, Waukesha, Wisconsin 53188 (United States)

    2016-01-15

    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

  15. 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.

  16. 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.

  17. 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

  18. Single-well and inter-well dual-tracer test design for quantifying phase volumes and interface areas in subsurface flow and transport systems

    Science.gov (United States)

    Ghergut, I.; Behrens, H.; Licha, T.; Maier, F.; Nottebohm, M.; Schaffer, M.; Sauter, M.

    2012-04-01

    Technology-relevant georeservoirs in the realm of energy production (such as: spent-radionuclide repositories, gas-storage, geothermal, as well as CCS candidate reservoirs) contain mobile and immobile fluid regions, and often also different fluid and solid phases. The lifetime of a particular reservoir (from a hydraulic, thermal, geomechanical and/or hydrogeochemical point of view) depends on the volumes and/or interface areas of some of these regions and/or phases. Mostly, their lifetime-effective values cannot be measured by geophysical and hydraulic methods. Since they essentially relate to fluid-based transport processes, attempting to measure them by tracer tests is a sensible endeavour. However, in designing and dimensioning such tracer tests, one should keep in mind that not every tracer test is sensitive w. r. to every fluid transport parameter. A certain complementarity exists, w. r. to parameter sensitivity, between single-well and inter-well methods, between equilibrium and kinetic exchange processes, between volume and area parameters. Mobile-fluid volumes can be measured from inter-well conservative-tracer tests, whereas single-well push-pull tests are generally insensitive w. r. to mobile-fluid volumes. Immobile-fluid volumes, in single-phase systems, are rather difficult to measure, by either kind of test. Different-phase volumes can be determined from inter-well tests using partitioning tracers at equilibrium exchange between phases; whereas single-well tracer push-pull tests are rather insensitive w. r. to tracer exchange processes at equilibrium. Im-/mobile fluid, or inter-phase interface areas can be determined from single-well tracer push-pull tests relying on kinetic exchange processes between compartments or phases. Single-well tests are often believed to be more sensitive w. r. to such processes than w. r. to advective-dispersive processes, and than inter-well tests. Inter-well tests are not physically insensitive w. r. to kinetic exchange

  19. 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)

  20. 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.

  1. 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.

  2. Modeling and analysis of variable speed single phase induction motors with iron loss

    International Nuclear Information System (INIS)

    Vaez-Zadeh, S.; Zahedi, B.

    2009-01-01

    Despite their usual low power ratings of single phase induction motors, they consume a considerable part of total motors energy consumption due to their large and ever-increasing quantity. The recent rising of oil prices and environmental crises has fortified the idea of energy saving practices in all applications; particularly in single phase induction motors due to their typical low efficiency. An essential requirement for this practice is the modeling and analysis of machine electrical losses under variable frequency operation. In this paper an improved steady state model of single phase induction motors is derived to investigate major motor characteristics like torque-speed, input power, output power, etc. A special emphasis is placed on accurately representing core losses at variable frequency. The winding currents phase difference is reintroduced as a fundamental motor variable to determine motor performances including losses and efficiency. An advanced computerized motor test setup is designed and built for on-line measurement of motor characteristics at different supply and operating conditions. The extensive experimental results, in good agreement with the simulation results based on the mentioned analysis, confirm the validity of the proposed model.

  3. Ion beam induced single phase nanocrystalline TiO{sub 2} formation

    Energy Technology Data Exchange (ETDEWEB)

    Rukade, Deepti A. [Department of Physics, University of Mumbai, Mumbai 400098 (India); Tribedi, L.C. [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India); Bhattacharyya, Varsha, E-mail: varsha.b1.physics@gmail.com [Department of Physics, University of Mumbai, Mumbai 400098 (India)

    2014-06-15

    Single phase TiO{sub 2} nanostructures are fabricated by oxygen ion implantation (60 keV) at fluence ranging from 1×10{sup 16} ions/cm{sup 2} to 1×10{sup 17} ions/cm{sup 2} in titanium thin films deposited on fused silica substrate and subsequent thermal annealing in argon atmosphere. GAXRD and Raman spectroscopy study reveals formation of single rutile phases of TiO{sub 2}. Particle size is found to vary from 29 nm to 35 nm, establishing nanostructure formation. Nanostructure formation is also confirmed by the quantum confinement effect manifested by the blueshift of the UV–vis absorption spectra. Photoluminescence spectra show peaks corresponding to TiO{sub 2} rutile phase and reveal the presence of oxygen defects due to implantation. The controlled synthesis of single phase nanostructure is attributed to ion induced defects and post-implantation annealing. It is observed that the size of the nanostructures formed is strongly dependent on the ion fluence.

  4. 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

  5. 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.

  6. Massively Parallel Haplotyping on Microscopic Beads for the High-Throughput Phase Analysis of Single Molecules

    Science.gov (United States)

    Tiemann-Boege, Irene

    2012-01-01

    In spite of the many advances in haplotyping methods, it is still very difficult to characterize rare haplotypes in tissues and different environmental samples or to accurately assess the haplotype diversity in large mixtures. This would require a haplotyping method capable of analyzing the phase of single molecules with an unprecedented throughput. Here we describe such a haplotyping method capable of analyzing in parallel hundreds of thousands single molecules in one experiment. In this method, multiple PCR reactions amplify different polymorphic regions of a single DNA molecule on a magnetic bead compartmentalized in an emulsion drop. The allelic states of the amplified polymorphisms are identified with fluorescently labeled probes that are then decoded from images taken of the arrayed beads by a microscope. This method can evaluate the phase of up to 3 polymorphisms separated by up to 5 kilobases in hundreds of thousands single molecules. We tested the sensitivity of the method by measuring the number of mutant haplotypes synthesized by four different commercially available enzymes: Phusion, Platinum Taq, Titanium Taq, and Phire. The digital nature of the method makes it highly sensitive to detecting haplotype ratios of less than 1∶10,000. We also accurately quantified chimera formation during the exponential phase of PCR by different DNA polymerases. PMID:22558329

  7. 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.

  8. Single-image phase retrieval using an edge illumination X-ray phase-contrast imaging setup

    International Nuclear Information System (INIS)

    Diemoz, Paul C.; Vittoria, Fabio A.; Hagen, Charlotte K.; Endrizzi, Marco; Coan, Paola; Brun, Emmanuel; Wagner, Ulrich H.; Rau, Christoph; Robinson, Ian K.; Bravin, Alberto; Olivo, Alessandro

    2015-01-01

    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

  9. 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.

  10. 77 FR 73586 - Further Inquiry Into Issues Related to Mobility Fund Phase II

    Science.gov (United States)

    2012-12-11

    ..., including at the cell edge, at a high probability, and with substantial sector loading. The Commission... mobile broadband service in urban areas. Commenters generally recommend periodic review and modification...

  11. Reliable Grid Condition Detection and Control of Single-Phase Distributed Power Generation Systems

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai

    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...... of the entire system. Regarding the advance control of DPGS, an active damping technique for grid-connected systems using inductor-capacitorinductor (LCL) filters was proposed in the thesis. The method is based on a notch filter, whose stopband can be automatically adjusted in relation with an estimated value...

  12. 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...

  13. A MPPT Algorithm Based PV System Connected to Single Phase Voltage Controlled Grid

    Science.gov (United States)

    Sreekanth, G.; Narender Reddy, N.; Durga Prasad, A.; Nagendrababu, V.

    2012-10-01

    Future ancillary services provided by photovoltaic (PV) systems could facilitate their penetration in power systems. In addition, low-power PV systems can be designed to improve the power quality. This paper presents a single-phase PV systemthat provides grid voltage support and compensation of harmonic distortion at the point of common coupling thanks to a repetitive controller. The power provided by the PV panels is controlled by a Maximum Power Point Tracking algorithm based on the incremental conductance method specifically modified to control the phase of the PV inverter voltage. Simulation and experimental results validate the presented solution.

  14. 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)

  15. 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.

  16. 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.

  17. 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...... voltage. In the proposed inverter, the input DC source and the load or grid have the same ground. Therefore, the leakage current problem in photovoltaic (PV) systems is eliminated. Furthermore, the proposed inverter supports the bi-directional power flow capability and it can inject reactive power...

  18. 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

  19. 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.

  20. Effect of mobile phase additives on qualitative and quantitative analysis of ginsenosides by liquid chromatography hybrid quadrupole-time of flight mass spectrometry.

    Science.gov (United States)

    Liang, Yan; Guan, Tianye; Zhou, Yuanyuan; Liu, Yanna; Xing, Lu; Zheng, Xiao; Dai, Chen; Du, Ping; Rao, Tai; Zhou, Lijun; Yu, Xiaoyi; Hao, Kun; Xie, Lin; Wang, Guangji

    2013-07-05

    This study was to systematically investigate the effect of mobile phase additives, including ammonia water, formic acid, acetic acid, ammonium chloride and water (as a control), on qualitative and quantitative analysis of fifteen representative ginsenosides based on liquid chromatography hybrid quadrupole-time of flight mass spectrometry (LC-Q-TOF/MS). To evaluate the influence of mobile phase additives on qualitative performance, the quality of the negative mode MS/MS spectra of ginsenosides produced by online LC-Q-TOF/MS analyses, particularly the numbers and intensities of fragment ions, were compared under different adduct ion states, and found to be strongly affected by the mobile phase additives. When 0.02% acetic acid was added in the mobile phase, the deprotonated ginsenosides ions produced the most abundant product ions, while almost no product ion was observed for the chlorinated ginsenoside ions when 0.1mM ammonium chloride was used as the mobile phase additive. On the other hand, sensitivity, linear range and precision were adopted to investigate the quantitative performance affected by different mobile phase additives. Validation results of the LC-Q-TOF/MS-based quantitative performance for ginsenosides showed that ammonium chloride not only provided the highest sensitivity for all the target analytes, but also dramatically improved the linear ranges, the intra-day and inter-day precisions comparing to the results obtained using other mobile phase additives. Importantly, the validated method, using 0.1mM ammonium chloride as the mobile phase additive, was successfully applied to the quantitative analysis of ginsenosides in rat plasma after intragastric administration of Ginsenoside Extract at 200mg/kg. In conclusion, 0.02% acetic acid was deemed to be the most suitable mobile phase additive for qualitative analysis of ginsenosides, and 0.1mM ammonium chloride in mobile phase could lead to the best quantitative performance. Our results reveal that

  1. 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.

  2. Scan-less hyperspectral dual-comb single-pixel-imaging in both amplitude and phase

    Science.gov (United States)

    Shibuya, Kyuki; Minamikawa, Takeo; Mizutani, Yasuhiro; Yamamoto, Hirotsugu; Minoshima, Kaoru; Yasui, Takeshi; Iwata, Tetsuo

    2017-09-01

    We have developed a hyperspectral imaging scheme that involves a combination of dual-comb spectroscopy and Hadamard-transform-based single-pixel imaging. The scheme enables us to obtain 12,000 hyperspectral images of amplitude and phase at a spatial resolution of 46 um without mechanical scanning. The spectral resolution is 20 MHz, as determined by the linewidth of a single comb mode, and the spectral interval is 100 MHz over a spectral range of 1.2 THz centred at 191.5 THz. As an initial demonstration of our scheme, we obtained spectroscopic images of a standard test chart through an etalon plate. The thickness of an absorptive chromium-coated layer on a float-glass substrate was determined to be 70 nm from the hyperspectral phase images in the near-infrared wavelength region.

  3. 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...... attenuates) all harmonics up to the aliasing point under a nominal (off-nominal) frequency. The effectiveness of the designed OLS technique is verified using comparative experimental results....

  4. 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.

  5. 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...... used to reduce the torque ripple and enable self-starting of the machine. The starting torque of this machine is significantly improved by a slight extension of the stator pole-arc. A prototype machine and a complete drive system has been manufactured and tested. Results are given in this paper....

  6. Evaluation of 600V Superjunction Devices in Single Phase PFC Applications under CCM Operation

    DEFF Research Database (Denmark)

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

    2014-01-01

    This paper pr esents a power density/efficiency evaluation in single phase power factor correction (PFC) applications operating in continuous conduction mode (CCM). The comparison is based on semiconductor dynamic characterization and a mathematical model for prediction of the conducted electroma......This paper pr esents a power density/efficiency evaluation in single phase power factor correction (PFC) applications operating in continuous conduction mode (CCM). The comparison is based on semiconductor dynamic characterization and a mathematical model for prediction of the conducted...... electromagnetic interference (EMI). The dynamic characterization is based on a low inductive double pulse tester (DPT). The measured switching energy is used in order to evaluate the devices performance in a conventional PFC. This data is used together with the mathematical model for prediction of the conducted...... electromagnetic interference. The method allows comparing different devices and evaluating the performance as a function of the PFC power density and efficiency....

  7. Power decoupling with autonomous reference generation for single-phase differential inverters

    DEFF Research Database (Denmark)

    Yao, Wenli; Zhang, Xiaobin; Wang, Xiongfei

    2015-01-01

    The second-harmonic power ripple in single-phase inverter may introduce the issue of low reliability and low power density. In order to replace the bulky dc-link capacitor, an alternative approach is to use active power decoupling so that the ripple power can be diverted into other energy storages...... are used for realizing an improved power decoupling control, capacitor voltage and inductor current regulation. By substituting the corresponding parameter into unified model, the proposed control loop can be applied to different inverter types (Buck, Buck-Boost and Boost). Finally, detailed laboratory....... However, the performance of existing active power decoupling methods depends heavily on certain control references, which unfortunately are parameter dependent. In this paper an autonomous reference generation technique is proposed for single phase differential inverter without relying on the system...

  8. 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

    Power decoupling circuits can compensate the inherent double line frequency ripple power in single-phase systems and greatly facilitate their dc-link capacitor design. Example applications of power decoupling circuit include photovoltaic, light-emitting diode, fuel cell, and motor drive systems....... 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...

  9. 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...

  10. 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...... of output DC voltage. Moreover, the involved DC/DC buck conversion stage may only need to convert partial input power rather than full scale of input power, and therefore the system overall efficiency can be much improved. Through proper control of the buck converter, it is also possible to mitigate...... the double-line frequency ripple power that is inherent in a single-phase AC/DC system. Both simulation and experimental results are presented to show the effectiveness of this converter....

  11. 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...... capability. The control methods, together with grid synchronization techniques, are responsible for the generation of appropriate reference signals in order to handle ride-through grid faults. Thus, it is necessary to evaluate the behaviors of grid synchronization methods and control possibilities in single...... 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...

  12. Improved Design Methods for Robust Single- and Three-Phase ac-dc-ac Power Converters

    DEFF Research Database (Denmark)

    Qin, Zian

    After a century of fast developing, the society is facing energy issues again, e.g. the exhaustion of fossil fuel, emission caused air pollution, radiation leakage of nuclear generation, and so on. How to produce and use electricity in a more sustainable, efficient, and cost-effective way thus...... 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......, the emerging challenges, and the structure of the thesis. The main content of the thesis starts with single-phase converters: Chapter 2 and Chapter 3 propose new modulation methods for single-phase B6 and H6 converters, respectively, in order to retain the same dc link voltage with two full-bridges connected...

  13. Strain-hardening in nano-structured single phase steels: mechanisms and control.

    Science.gov (United States)

    Bouaziz, O; Barbier, D

    2012-11-01

    The detrimental effect of grain size refinement on the strain hardening is highlighted in single phase steels. A physical based approach for understanding the underlying mechanisms is presented. In order to overcome this limitation a promising metallurgical route exploiting the thermal stability of mechanically induced twins in austenitic steels has been successfully applied to a stainless grade confirming the opportunity to get nano-structured alloys exhibiting high yield stress with high strain-hardening.

  14. 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 f...... the excellent performance of the suggested approach. Theoretical evaluations are confirmed by experimental results....

  15. Vortex phase diagram studies in the weakly pinned single crystals of ...

    Indian Academy of Sciences (India)

    Vortex phase diagram studies in the weakly pinned single crystals of YNi2B2C and LuNi2B2C. D JAISWAL-NAGAR1,∗, D PAL2, M R ESKILDSEN2, P C CANFIELD3,. H TAKEYA4, S RAMAKRISHNAN1 and A K GROVER1,†. 1Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental ...

  16. Physical investigation of square cylinder array dynamical response under single-phase cross-flow

    International Nuclear Information System (INIS)

    Longatte, E.; Baj, F.

    2014-01-01

    Fluid structure interaction and flow-induced vibration in square cylinder arrangement under single-phase incompressible laminar cross flow are investigated in the present paper. Dynamic instability governed by damping generation is studied without any consideration about mixing with turbulence effects. Conservative and non-conservative effects are pointed out and dynamical stability limit sensitivity to physical parameters is analyzed. Finally the influence of key physical parameters on fluid solid dynamics interaction is quantified. (authors)

  17. All-optical phase-change memory in a single gallium nanoparticle.

    Science.gov (United States)

    Soares, Bruno F; Jonsson, Fredrik; Zheludev, Nikolay I

    2007-04-13

    We report on the first demonstration of a quaternary-logical resonatorless optical memory element with information encoded in the structural phase of a single 80 nm gallium nanoparticle. The size of the memory element is comparable with bits in next-generation hard disks, and radically smaller than previously suggested memories exploiting optical resonators. Furthermore, the energy required for switching the nanoparticle is an order of magnitude less than needed in DVD, DVR, or hard disk technologies.

  18. 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

    2015-01-01

    Single-phase ac/dc or dc/ac systems are inherently subject to the harmonic disturbance that 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. Unfortunately, such passive filtering...... power decoupling method, and both the input current and output voltage of the converter can be well regulated even when very small dc-link capacitors are employed....

  19. 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

  20. Peak shapes of acids and bases under overloaded conditions in reversed-phase liquid chromatography, with weakly buffered mobile phases of various pH: a thermodynamic interpretation.

    Science.gov (United States)

    Gritti, Fabrice; Guiochon, Georges

    2009-01-02

    We measured overloaded band profiles for a series of nine compounds (phenol, caffeine, 3-phenyl 1-propanol, 2-phenylbutyric acid, amphetamine, aniline, benzylamine, p-toluidine, and procainamidium chloride) on columns packed with four different C(18)-bonded packing materials: XTerra-C(18), Gemini-C(18), Luna-C(18)(2), and Halo-C(18), using buffered methanol-water mobile phases. The pHWS of the mobile phase was increased from 2.6 to 11.3. The buffer concentration (either phosphate, acetate, or carbonate buffers) was set constant at values below the maximum concentration of the sample in the band. The influence of the surface chemistry of the packing material on the retention and the shape of the peaks was investigated. Adsorbents having a hybrid inorganic/organic structure tend to give peaks exhibiting moderate or little tailing. The retention and the shape of the band profiles can easily be interpreted at pHsWS that are well above or well below the pKWS(a) of the compound studied. In contrast, the peak shapes in the intermediary pH range (i.e., close to the compound pKWS(a)) have rarely been studied. These shapes reveal the complexity of the competitive adsorption behavior of couples of acido-basic conjugated compounds at pHsWS that are close to their pKWS(a). They also reveal the role of the buffer capacity on the resulting peak shape. With increasing pHWS, the overloaded profiles are first langmuirian (isotherm type I) at low pHsWS, they become S-shaped (isotherm type II), then anti-langmuirian (isotherm type III), S-shaped again at intermediate pHsWS, and finally return to a langmuirian shape at high pHsWS. A new general adsorption isotherm model that takes into account the dissociation equilibrium of conjugated acidic and basic species in the bulk mobile phase accounts for these transient band shapes. An excellent agreement was achieved between experimental profiles and those calculated with a two-sites adsorption isotherm model at all pHsWS. The neutral

  1. Abrasion resistance, microhardness and microstructures of single-phase niobium nitride films

    International Nuclear Information System (INIS)

    Singer, I.L.; Bolster, R.N.; Wolf, S.A.; Skelton, E.F.; Jeffries, R.A.

    1983-01-01

    The relative abrasive wear resistance of single-phase niobium nitride films deposited at 900 and 500 0 C was measured. Wear resistance versus depth profiles of films abraded against 1-5 μm diamond were obtained by weight loss methods. A β phase Nb 2 N film was five to 20 times more abrasion resistant, but only slightly (40%) harder, than the delta phase NbN films made at the same temperature. The β-Nb 2 N film was deformed plastically during wear, reorienting the [002] c axis perpendicular to the plane of the substrate. The abrasion resistance of the delta-NbN films was initially proportional to the microhardness. Two films had changes in their abrasion resistance as wear proceeded: for one film the change was attributable to deviations in stoichiometry and for the other film it was attributable to increased lattice distortion. (Auth.)

  2. 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....

  3. 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.

  4. 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.

  5. Tensile loading induced phase transition and rippling in single-layer MoS2

    Science.gov (United States)

    Bao, Hongwei; Huang, Yuhong; Yang, Zhi; Miao, Yaping; Chu, Paul K.; Xu, Kewei; Ma, Fei

    2017-05-01

    Molecular dynamics (MD) simulation is performed to study the structural evolution of single-layer MoS2 nanosheets under tensile loading and a phase transition from hexagonal structure to quadrilateral one is observed at a large strain when loaded along the zigzag direction but not along the armchair direction. Density functional theory (DFT) calculation illustrates that the newly generated quadrilateral phase is metallic. Further loading along the zigzag direction promotes an inhomogeneous distribution of lateral and shear stress around the phase boundaries due to local mechanical mismatch. As a result, periodic rippling parallel to the loading direction emerges and the wavelength and wave height change with strain according to λ∼ε-1/4 and h∼ε1/4. Accordingly, a graded distribution of strain can be produced or modulated by a simple tensile loading and the strategy might be utilized to enhance the photoelectrical properties of 2D materials and design strain-tunable nanodevices.

  6. 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....

  7. Investigation of snow single scattering properties based on first order Legendre phase function

    Science.gov (United States)

    Eppanapelli, Lavan Kumar; Casselgren, Johan; Wåhlin, Johan; Sjödahl, Mikael

    2017-04-01

    Angularly resolved bidirectional reflectance measurements were modelled by approximating a first order Legendre expanded phase function to retrieve single scattering properties of snow. The measurements from 10 different snow types with known density and specific surface area (SSA) were investigated. A near infrared (NIR) spectrometer was used to measure reflected light above the snow surface over the hemisphere in the wavelength region of 900-1650 nm. A solver based on discrete ordinate radiative transfer (DISORT) model was used to retrieve the estimated Legendre coefficients of the phase function and a correlation between the coefficients and physical properties of different snow types is investigated. Results of this study suggest that the first two coefficients of the first order Legendre phase function provide sufficient information about the physical properties of snow where the latter captures the anisotropic behaviour of snow and the former provides a relative estimate of the single scattering albedo of snow. The coefficients of the first order phase function were compared with the experimental data and observed that both the coefficients are in good agreement with the experimental data. These findings suggest that our approach can be applied as a qualitative tool to investigate physical properties of snow and also to classify different snow types.

  8. 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

  9. High-resolution peptide mapping separations with MS-friendly mobile phases and charge-surface-modified C18.

    Science.gov (United States)

    Lauber, Matthew A; Koza, Stephan M; McCall, Scott A; Alden, Bonnie A; Iraneta, Pamela C; Fountain, Kenneth J

    2013-07-16

    Ionic analytes, such as peptides, can be challenging to separate by reverse-phase chromatography with optimal efficiency. They tend, for instance, to exhibit poor peak shapes, particularly when eluted with mobile phases preferred for electrospray ionization mass spectrometry. We demonstrate that a novel charged-surface C18 stationary phase alleviates some of the challenges associated with reverse-phase peptide separations. This column chemistry, known as CSH (charged-surface hybrid) C18, improves upon an already robust organosilica hybrid stationary phase, BEH (ethylene-bridged hybrid) C18. Based on separations of a nine-peptide standard, CSH C18 was found to exhibit improved loadability, greater peak capacities, and unique selectivity compared to BEH C18. Its performance was also seen to be significantly less dependent on TFA-ion pairing, making it ideal for MS applications where high sensitivity is desired. These performance advantages were evaluated through application to peptide mapping, wherein CSH C18 was found to aid the development of a high-resolution, high-sensitivity LC-UV-MS peptide mapping method for the therapeutic antibody, trastuzumab. From these results, the use of a C18 stationary phase with a charged surface, such as CSH C18, holds significant promise for facilitating challenging peptide analyses.

  10. 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...

  11. Small-Signal Analysis of Single-Phase and Three-phase DC/AC and AC/DC PWM Converters with the Frequency-Shift Technique

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Aquila, A. Dell’; Liserre, Marco

    2004-01-01

    of dc/dc converters via a 50 Hz frequency-shift. The input admittance is calculated and measured for two study examples (a three-phase active rectifier and a single-phase photovoltaic inverter). These examples show that the purpose of a well designed controller for grid-connected converters......A systematic approach to study dc/ac and ac/dc converters without the use of synchronous transformation is proposed. The use of a frequency-shift technique allows a straightforward analysis of single-phase and three-phase systems. The study of dc/ac and of ac/dc converters is reported to the study...

  12. 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 condition of conserved vacancy density and nonconserved Potts order. The dynamics of ordering and phase separation is found to follow algebraic growth laws with exponent values that depend on the phase to which the quench is performed. Strong transient effects are observed in the dilute Potts-ordered phase...

  13. 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

  14. 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...... 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...

  15. Phase change material for thermotherapy of Buruli ulcer: a prospective observational single centre proof-of-principle trial.

    Directory of Open Access Journals (Sweden)

    Thomas Junghanss

    Full Text Available BACKGROUND: Buruli ulcer (BU is an infection of the subcutaneous tissue leading to chronic necrotizing skin ulcers. The causative pathogen, Mycobacterium ulcerans, grows best at 30 degrees C-33 degrees C and not above 37 degrees C. We explored the safety, tolerability and efficacy of phase change material (PCM, a novel heat application system for thermotherapy of BU. METHODOLOGY/PRINCIPAL FINDINGS: In a prospective observational single centre proof-of-principle trial in Ayos/Cameroon, six laboratory reconfirmed patients with ulcerative Buruli lesions received 28-31 (ulcers 2 cm days of thermotherapy with the PCM sodium acetate trihydrate as heat application system. This PCM is widely used in commercial pocket heat pads, it is easy to apply, rechargeable in hot water, non-toxic and non-hazardous to the environment. All patients enrolled in the trial completed treatment. Being completely mobile during the well-tolerated heat application, acceptability of the PCM bandages was very high. In patients with smaller ulcers, wounds healed completely without further intervention. Patients with large defects had skin grafting after successful heat treatment. Heat treatment was not associated with marked increases in local inflammation or the development of ectopic lymphoid tissue. One and a half years after completion of treatment, all patients are relapse-free. CONCLUSIONS/SIGNIFICANCE: Our reusable PCM-based heat application device appears perfectly suited to treat BU in endemic countries with limited resources and infrastructure. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN88392614.

  16. Charge-carrier mobilities in Cd(0.8)Zn(0.2)Te single crystals used as nuclear radiation detectors

    Science.gov (United States)

    Burshtein, Z.; Jayatirtha, H. N.; Burger, A.; Butler, J. F.; Apotovsky, B.; Doty, F. P.

    1993-01-01

    Charge-carrier mobilities were measured for the first time in Cd(0.8)Zn(0.2)Te single crystals using time-of-flight measurements of charge carriers produced by short (10 ns) light pulses from a frequency-doubled Nd:YAG laser (532 nm). The electron mobility displayed a T exp -1.1 dependence on the absolute temperature T in the range 200-320 K, with a room-temperature mobility of 1350 sq cm/V s. The hole mobility displayed a T exp -2.0 dependence in the same temperature range, with a room-temperature mobility of 120 sq cm/V s. Cd(0.8)Zn(0.2)Te appears to be a very favorable material for a room-temperature electronic nuclear radiation detector.

  17. 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.

  18. Artificial neural network modelling of retention of pesticides in various octadecylsiloxane-bonded reversed-phase columns and water-acetonitrile mobile phase.

    Science.gov (United States)

    D'Archivio, Angelo Antonio; Maggi, Maria Anna; Mazzeo, Pietro; Ruggieri, Fabrizio

    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, logK(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-microm 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-microm stationary phases and on a 4-microm external column. This analysis reveals that accuracy of retention prediction for unknown solutes in unknown columns is acceptable provided that the external column is

  19. 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

  20. 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.

  1. Analysis of erythromycin by liquid chromatography/mass spectrometry using involatile mobile phases with a novel atmospheric pressure ionization source.

    Science.gov (United States)

    Bajic, S; Doerge, D R; Lu, L; Hansen, E B

    2000-01-01

    A critical limitation of electrospray ionization (ESI) liquid chromatography/mass spectrometry (LC/MS) sources is the susceptibility to blockage of interface orifices due to the deposition of involatile components from the sample and/or mobile phase. These components, including salts, buffers, and ion-pairing agents, can be essential to the performance of the chosen analytical method. We report here the performance enhancements provided by a novel atmospheric pressure ionization (API) source in the analysis of erythromycin A (ERY) using mobile phases that contain involatile components. The enhanced robustness of the new source is derived from the use of a continuous flow of aqueous solvent at the sampling cone orifice that maintains unobstructed ion transmission. The ESI mass spectral responses measured for ERY, using an LC separation that incorporates 10 mM sodium phosphate with and without 10 mM octane sulfonate, were monitored by repeated injections over 13-15 h total analysis time. Minimal effects on ESI mass spectral responses (integrated peak area) or chromatographic performance (peak shape, retention time) were observed during these studies. In the absence of the aqueous cleaning flow, complete loss of mass spectral responses and total blocking of the sampling cone was observed in less than 30 min. Responses for ERY spiked into chicken and beef liver, and catfish muscle at or below the regulatory level of interest (100 ppb), were quantified by internal standard calibration using this procedure. These results demonstrate the ability of a novel API-MS ion source to perform analyses that require the use of involatile mobile phase additives. Copyright 2000 John Wiley & Sons, Ltd.

  2. Advanced heat pump for recovery of volatile organic compounds, Phase III - demonstration of BCSRHP mobile regenerator. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1994-11-01

    Under Phase I of the subject contract, feasibility studies and basic engineering studies were performed for a Brayton Cycle Solvent Recovery Heat Pump (BCSRBP) system to prevent pollution from small source emitters. It was determined that the cost of a complete system, including adsorbers and regeneration process, would be far too much for the small emission source in most cases. This {open_quotes}integrated{close_quotes} approach was therefore not feasible. However, it was concluded that the expensive portion of the Brayton cycle process, the regenerator, could be shared by mounting it on a trailer that could be transported to different sites to regenerate an adsorber. Under Phase II of the project a mobile regenerator (BCSRI-IP) was designed and built to serve a large number of sites. Adsorbers were designed to control emissions for a week or more between regenerations. The purpose of phase III was to demonstrate the cost effectiveness and efficiency of the shared (decoupled) BRAYSORB{reg_sign} solvent recovery system in energy use and emission control compared to other control technologies through a performance testing program at representative industrial and commercial host sites in Southern California. NUCON was the prime contractor for the demonstration portion of this project. Support and funding were received from Southern California Edison Company, South Coast Air Quality Management District, and the U.S. Department of Energy in addition to the contribution by NUCON. Contractual arrangements were completed with each of the host sites and permits for both the stationary and mobile equipment were acquired. The adsorbers were installed at each host site and the appropriate interface connections were made. The mobile regenerator was transported to Southern California for the demonstration.

  3. 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

  4. Single-channel color image encryption using phase retrieve algorithm in fractional Fourier domain

    Science.gov (United States)

    Sui, Liansheng; Xin, Meiting; Tian, Ailing; Jin, Haiyan

    2013-12-01

    A single-channel color image encryption is proposed based on a phase retrieve algorithm and a two-coupled logistic map. Firstly, a gray scale image is constituted with three channels of the color image, and then permuted by a sequence of chaotic pairs generated by the two-coupled logistic map. Secondly, the permutation image is decomposed into three new components, where each component is encoded into a phase-only function in the fractional Fourier domain with a phase retrieve algorithm that is proposed based on the iterative fractional Fourier transform. Finally, an interim image is formed by the combination of these phase-only functions and encrypted into the final gray scale ciphertext with stationary white noise distribution by using chaotic diffusion, which has camouflage property to some extent. In the process of encryption and decryption, chaotic permutation and diffusion makes the resultant image nonlinear and disorder both in spatial domain and frequency domain, and the proposed phase iterative algorithm has faster convergent speed. Additionally, the encryption scheme enlarges the key space of the cryptosystem. Simulation results and security analysis verify the feasibility and effectiveness of this method.

  5. Single-phase and two-phase flow properties of mesaverde tight sandstone formation; random-network modeling approach

    Science.gov (United States)

    Bashtani, Farzad; Maini, Brij; Kantzas, Apostolos

    2016-08-01

    3D random networks are constructed in order to represent the tight Mesaverde formation which is located in north Wyoming, USA. The porous-space is represented by pore bodies of different shapes and sizes which are connected to each other by pore throats of varying length and diameter. Pore bodies are randomly distributed in space and their connectivity varies based on the connectivity number distribution which is used in order to generate the network. Network representations are then validated using publicly available mercury porosimetry experiments. The network modeling software solves the fundamental equations of two-phase immiscible flow incorporating wettability and contact angle variability. Quasi-static displacement is assumed. Single phase macroscopic properties (porosity, permeability) are calculated and whenever possible are compared to experimental data. Using this information drainage and imbibition capillary pressure, and relative permeability curves are predicted and (whenever possible) compared to experimental data. The calculated information is grouped and compared to available literature information on typical behavior of tight formations. Capillary pressure curve for primary drainage process is predicted and compared to experimental mercury porosimetry in order to validate the virtual porous media by history matching. Relative permeability curves are also calculated and presented.

  6. 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.

  7. 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.

  8. Non-Orthogonal Multiple Access and Carrierless Amplitude Phase Modulation for 5G Mobile Networks

    DEFF Research Database (Denmark)

    Altabas, Jose A.; Rommel, Simon; Puerta Ramírez, Rafael

    2017-01-01

    A combined NOMA and multiCAP scheme is proposed for capacity enhancement of 5G mobile networks and experimentally tested over a W-band millimeter-wave radio-over-fiber system. The evaluated NOMA-CAP system provides an aggregated transmission rate of 30Gbps....

  9. 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.

  10. Development of an achiral supercritical fluid chromatography method with ultraviolet absorbance and mass spectrometric detection for impurity profiling of drug candidates. Part I: Optimization of mobile phase composition.

    Science.gov (United States)

    Lemasson, Elise; Bertin, Sophie; Hennig, Philippe; Boiteux, Hélène; Lesellier, Eric; West, Caroline

    2015-08-21

    Supercritical fluid chromatography (SFC) is a very useful tool in the purpose of impurity profiling of drug candidates, as an adequate selection of stationary phases can provide orthogonal separations so as to maximize the chances to see all impurities. The purpose of the present work is to develop a method for chemical purity assessment. The first part, presented here, focuses on mobile phase selection to ensure adequate elution and detection of drug-like molecules, while the second part focuses on stationary phase selection for optimal separation and orthogonality. The use of additives in the carbon dioxide - solvent mobile phase in SFC is now commonplace, and enables in particular to increase the number of eluted compounds and to improve peak shapes. The objective of this first part was to test different additives (acids, bases, salts and water) for their chromatographic performance assessed in gradient elution with a diode-array detector, but also for the mass responses obtained with a single-quadrupole mass detector, equipped with an electrospray ionization source (Waters ACQUITY QDa). In this project, we used a selection of one hundred and sixty compounds issued from Servier Research Laboratories to screen a set of columns and additives in SFC with a Waters ACQUITY UPC(2) system. The selected columns were all high-performance columns (1.7-1.8μm with totally porous particles or 2.6-2.7μm with superficially porous particles) with a variety of stationary phase chemistries. Initially, eight additives dissolved in the methanol co-solvent were tested on a UPC(2) ACQUITY UPC(2) HSS C18 SB column. A Derringer desirability function was used to classify the additives according to selected criteria: elution capability, peak shapes, UV baseline drift, and UV and mass responses (signal-to-noise ratios). Following these tests, the two best additives (ammonium acetate and ammonium hydroxide) were tested on a larger number of columns (10) where the two additives appeared

  11. Chirality-Dependent Vapor-Phase Epitaxial Growth and Termination of Single-Wall Carbon Nanotubes

    Science.gov (United States)

    Liu, Bilu; Liu, Jia; Zhou, Chongwu; USC nanolab Team

    2014-03-01

    Chirality-pure single-wall carbon nanotubes are highly desired for both fundamental study and many of their technological applications. Recently, we have shown that chirality-pure short nanotubes can be used as seeds for vapor-phase epitaxial cloning growth, opening up a new route toward chirality-controlled carbon nanotube synthesis. Nevertheless, the yield of vapor-phase epitaxial growth is rather limited at the present stage, due to the lack of mechanistic understanding of the process. Here we report chirality-dependent growth kinetics and termination mechanism for the vapor-phase epitaxial growth of seven single- chirality nanotubes of (9, 1), (6, 5), (8, 3), (7, 6), (10, 2), (6, 6), and (7, 7), covering near zigzag, medium chiral angle, and near armchair semiconductors, as well as armchair metallic nanotubes. Our results reveal that the growth rates of nanotubes increase with their chiral angles while the active lifetimes of the growth hold opposite trend. Consequently, the chirality distribution of a nanotube ensemble is jointly determined by both growth rates and lifetimes. These results correlate nanotube structures and properties with their growth behaviors and deepen our understanding of chirality-controlled growth of nanotubes.

  12. 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)

  13. 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.

  14. Bidirectional reflectance spectroscopy 7. The single particle phase function hockey stick relation

    Science.gov (United States)

    Hapke, Bruce

    2012-11-01

    The measured volume-average single particle angular scattering functions of a large number of types of particle of interest for planetary regoliths in the visible-near-IR wavelength region can be represented to a reasonable approximation by two-parameter, double Henyey-Greenstein functions. When the two parameters of this function are plotted against one another they are found to be inversely correlated and lie within a restricted zone shaped like a hockey stick within the parameter space. The centroid of the zone is a curve that can be represented by a simple empirical equation. The wide variety of types of particles used to construct the plot implies that this equation may represent most of the particles found in regoliths. This means that when modeling the bidirectional reflectance of a regolith it may be possible to reduce the number of parameters necessary to specify the reflectance, and also to characterize the entire single particle phase function from observations at phase angles less than 90°. Even if the hockey stick relation has a finite width, rather than being a line, it restricts the parameter space that must be searched when fitting data. The curve should also be useful for forward modeling particle phase functions.

  15. 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.

  16. 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)

  17. 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

  18. 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.

  19. 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

  20. Determination of gas phase triacetone triperoxide with aspiration ion mobility spectrometry and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Räsänen, Riikka-Marjaana; Nousiainen, Marjaana; Peräkorpi, Kaleva; Sillanpää, Mika; Polari, Lauri; Anttalainen, Osmo; Utriainen, Mikko

    2008-08-08

    Aspiration ion mobility spectrometry (IMS) has been used for the first time to screen 3,3,6,6,9,9-hexamethyl-1,2,4,5,7,8-hexaoxacyclononane explosive, the most commonly known as triacetone triperoxide (TATP). Gaseous TATP was generated from synthesized solid compound, sublimed and directed to a portable chemical detection system comprised of an aspiration-type IMS detector and six semiconductor sensors. Different unknown TATP gas phase concentrations were produced and corresponding IMS and semiconductor responses were measured. The experimental concentrations were determined by gas chromatography-mass spectrometry (GC-MS). The results evidenced that the monitored compound in the gas phase was TATP. In addition, the determined TATP concentrations and corresponding IMS intensities showed that the IMS response values were proportional to the measured TATP concentrations.

  1. Totally robotic single-position 'flip' arm technique for splenic flexure mobilizations and low anterior resections.

    Science.gov (United States)

    Obias, Vincent; Sanchez, Caroline; Nam, Arthur; Montenegro, Grace; Makhoul, Rami

    2011-06-01

    Using the da Vinci robot in low anterior resection (LAR) has not been widely adopted due to limited range of motion of the robotic arms and the need to move the robot during operations. Our technique uses all three arms for both the splenic flexure and the pelvis, but with only one docking position. The robot is placed to the left of the patient. The camera port is 3 cm to the right of the umbilicus. Arm 1 is placed in the RLQ. Arm 2 is placed midepigastric. Arm 3 is placed in the LLQ. Arm 3 starts off on the left side of the robot, on the same side as Arm 1 aimed cephalad. During mobilization of colon and splenic flexure, Arms 2 and 3 help retract the colon while Arm 1 dissects. Our pelvic dissection begins with Arm 3 "flipped" to the right side of the robot and redocked to the same left sided port aimed caudally. The robot does not need to be repositioned and the patient does not need to be moved. The pelvic dissection can now be done in the standard fashion. Our early experience includes four patients: two LARs and two left hemicolectomies. Mean operative time = 347 minutes, docking time = 20 minutes, and robotic surgical time = 195 minutes. Two complications occurred: post-operative ileus and high ostomy output. Mean LOS = 5. The robotic "flip" arm technique allows the surgeon to fully utilize all the robotic arms in LAR, which is unique versus other techniques. Copyright © 2011 John Wiley & Sons, Ltd.

  2. 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...

  3. Phases in development of an interactive mobile phone-based system to support self-management of hypertension

    Directory of Open Access Journals (Sweden)

    Hallberg I

    2014-05-01

    Full Text Available Inger Hallberg,1,11 Charles Taft,1,11 Agneta Ranerup,2,11 Ulrika Bengtsson,1,11 Mikael Hoffmann,3,10 Stefan Höfer,4 Dick Kasperowski,5 Åsa Mäkitalo,6 Mona Lundin,6 Lena Ring,7,8 Ulf Rosenqvist,9 Karin Kjellgren1,10,11 1Institute of Health and Care Sciences, 2Department of Applied Information Technology, University of Gothenburg, Gothenburg, 3The NEPI Foundation, Linköping, Sweden; 4Department of Medical Psychology, Innsbruck Medical University, Innsbruck, Austria; 5Department of Philosophy, Linguistics and Theory of Science, 6Department of Education, Communication and Learning, University of Gothenburg, Gothenburg, 7Centre for Research Ethics and Bioethics, Uppsala University, 8Department of Use of Medical Products, Medical Products Agency, Uppsala, 9Department of Medical Specialist and Department of Medical and Health Sciences, Linköping University, Motala, 10Department of Medical and Health Sciences, Linköping University, Linköping, 11Centre for Person-Centred Care, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden Abstract: Hypertension is a significant risk factor for heart disease and stroke worldwide. Effective treatment regimens exist; however, treatment adherence rates are poor (30%–50%. Improving self-management may be a way to increase adherence to treatment. The purpose of this paper is to describe the phases in the development and preliminary evaluation of an interactive mobile phone-based system aimed at supporting patients in self-managing their hypertension. A person-centered and participatory framework emphasizing patient involvement was used. An interdisciplinary group of researchers, patients with hypertension, and health care professionals who were specialized in hypertension care designed and developed a set of questions and motivational messages for use in an interactive mobile phone-based system. Guided by the US Food and Drug Administration framework for the development of patient-reported outcome

  4. Phase diagram of the Ge-rich of the Ba–Ge system and characterisation of single-phase BaGe{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Prokofieva, Violetta K.; Pavlova, Lydia M., E-mail: fhim@mail.ru

    2014-06-25

    Highlights: • The Ba-Ge phase diagram for the range 50–100 at.% Ge was constructed. • Single-phase BaGe{sub 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{sub 4} grown by the Czochralski crystal pulling method was characterised. Semiconducting BaGe{sub 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.

  5. High Performance Harmonic Isolation By Means of The Single-phase Series Active Filter Employing The Waveform Reconstruction Method

    DEFF Research Database (Denmark)

    Senturk, Osman Selcuk; Hava, Ahmet M.

    2009-01-01

    This paper proposes the Waveform Reconstruction Method (WRM), which is utilized in the single-phase Series Active Filter's (SAF's) control algorithm, in order to extract the load harmonic voltage component of voltage harmonic type single-phase diode rectifier loads. Employing WRM and the line...... current sampling delay reduction method (SDRM), a single-phase SAF compensated system provides higher harmonic isolation performance and higher stability margins compared to the system using conventional synchronous reference frame based methods. The analytical, simulation, and experimental studies of a 2...

  6. 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.

  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. Selective distributions of functionalized single-walled carbon nanotubes in a polymeric reverse hexagonal phase.

    Science.gov (United States)

    Ha, Jae-Min; Jang, Hyung-Sik; Lim, Sung-Hwan; Choi, Sung-Min

    2015-08-07

    We have investigated the distributions of individually isolated and hydrophilically functionalized single-walled carbon nanotubes (p-SWNTs) in the Pluronic L121-water system at the reverse hexagonal phase using small-angle X-ray scattering (SAXS) and contrast-matched small-angle neutron scattering (SANS) measurements. As the p-SWNT-L121-water system is transitioned from the lamellar phase to the reverse hexagonal phase with temperature, p-SWNTs which were selectively distributed in the polar layers of the lamellar structure become selectively distributed in the cylindrical polar cores of the reverse hexagonal structure, forming a hexagonal array of p-SWNTs. This was clearly confirmed by the contrast-matched SANS measurements. The selective distribution of p-SWNTs in the reverse hexagonal phase is driven by the selective affinity of p-SWNTs to the polar domains of the block copolymer system. The method demonstrated in this study provides a new route for fabricating ordered SWNT superstructures and may be applicable for inorganic 1D nanoparticles such as semiconducting, metallic and magnetic nanorods which are of great interest.

  10. 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...

  11. 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.

  12. Single-Phase Microgrid with Seamless Transition Capabilities between Modes of Operation

    DEFF Research Database (Denmark)

    Micallef, Alexander; Apap, Maurice; Spiteri-Staines, Cyril

    2015-01-01

    Microgrids are an effective way to increase the penetration of DG into the grid. They are capable of operating either in grid-connected or in islanded mode thereby increasing the supply reliability for the end user. This paper focuses on achieving seamless transitions from islanded to grid......-connected and vice versa for a single phase microgrid made up from voltage controlled voltage source inverters (VC-VSIs) and current controlled voltage source inverters (CC-VSIs) working together in both modes of operation. The primary control structures for the VC-VSIs and CC-VSIs is considered together...... with the secondary control loops that are used to synchronize the microgrid as a single unit to the grid. Simulation results are given that show the seamless transitions between the two modes without any disconnection times for the CC-VSIs and VC-VSIs connected to the microgrid....

  13. 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.

  14. 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

  15. Stability of the single-mode output of a laser diode array with phase conjugate feedback

    DEFF Research Database (Denmark)

    Juul Jensen, S.; Løbel, M.; Petersen, P.M.

    2000-01-01

    . The output power and the center wavelength are found to be extremely stable in a 100 h stability measurement. External feedback of the output beam into the laser is seen to decrease both the spatial and the temporal coherence of the output significantly. We outline an approach to obtain a stable single......The stability of the output of a single-mode laser diode array with frequency selective phase conjugate feedback has been investigated experimentally. Both the long-term stability of the laser output and the sensitivity to feedback generated by external reflection of the output beam are examined......-mode output when external feedback is present using spatial filtering in the path of the output beam. (C) 2000 American Institute of Physics....

  16. Scaling analysis for the ocean motions in single phase natural circulation

    International Nuclear Information System (INIS)

    Yan, B.H.; Wen, Q.L.

    2015-01-01

    Highlights: • The scaling criteria for ocean motions are obtained. • The optimization and selection of the scaling criteria is also analyzed. • The oscillating period in experiments is determined by the time scale. - Abstract: The effects of ocean motions should be analyzed properly in order to guarantee the safety margin of facilities in the engineering design of floating nuclear reactor system. The scaling analysis for the ocean motions in single phase natural circulation is performed. The scaling criteria for both single ocean motions and compound ocean motions are obtained. The selection and optimization of scaling criteria is also analyzed. The oscillating amplitude in experiments should be kept to be identical to that in actual ocean motions. The oscillating period is determined by the time scale. The length scale, oscillating period and experimental power should be taken into consideration synthetically to obtain a reasonable experimental period

  17. 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 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......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...... 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...

  18. 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

  19. 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.

  20. 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...... to the harmonic voltage distortion without affecting the dynamic response of the synchronization. Therefore, the accurate response of the proposed MHDC-PLL enhances the power quality of the PV inverter systems and additionally, the proper fault ride-through operation of PV systems can be enabled by the fast...

  1. 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......The internal model principle based Repetitive Control (RC) offers an accurate control strategy for grid-tied power converters to feed sinusoidal current into the grid. However, in the presence of grid frequency variations, the conventional RC fails to produce high quality feeding current...... the proposed controller....

  2. Design and analysis of sensorless torque optimization for single phase induction motors

    International Nuclear Information System (INIS)

    Vaez-Zadeh, S.; Payman, A.

    2006-01-01

    Single phase induction motors are traditionally used in constant speed applications and suffer from unsymmetrical performance. A reliable speed signal can improve their performance and extend their applications as variable speed drives. In this paper, a speed estimation method for these motors is proposed based on a machine model in the stator flux reference frame. The method is examined in a sensorless torque optimization system over a wide operating range. Extensive simulation results prove the validity of the proposed method. Also, the motor performance under the torque optimization system is analyzed

  3. 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.

  4. 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)

  5. An LLCL Power Filter for Single-Phase Grid-Tied Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; He, Yuanbin; Blaabjerg, Frede

    2012-01-01

    This paper presents a new topology of higher order power filter for grid-tied voltage-source inverters, named the LLCL filter, which inserts a small inductor in the branch loop of the capacitor in the traditional LCL filter to compose a series resonant circuit at the switching frequency...... to the inverter system control. The parameter design criteria of the proposed LLCL filter is also introduced. The comparative analysis and discussions regarding the traditional LCL filter and the proposed LLCL filter have been presented and evaluated through experiment on a 1.8-kW-single-phase grid-tied inverter...

  6. 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...

  7. 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.

  8. A low capacitance single-phase AC-DC converter with inherent power ripple decoupling

    OpenAIRE

    Gottardo, Davide; De Lillo, Liliana; Empringham, Lee; Costabeber, Alessando

    2016-01-01

    This paper proposes a new single-phase AC-DC conversion topology with inherent power ripple decoupling, based on the combination of a PWM H-bridge inverter, an AC side LC filter and a ZVS line commutated H-bridge. A capacitor on the AC side is used as power decoupling element. By appropriate selection of the capacitor voltage, the power ripple at twice the AC frequency can be cancelled from the DC side instantaneous power, achieving negligible DC voltage ripple using a smaller total capacitan...

  9. 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

  10. 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

    and low computational burden. Meanwhile, some other techniques have been proposed to enhance system robustness and stability characteristics. In this paper, a comprehensive comparison among the OSG-based PLLs and the advanced single-phase PLLs is presented when the grid voltage undergoes disturbances......, and the performance comparison of transient response and disturbance rejection capabilities are presented. Finally, the moving average filter (MAF) is applied to enhance steady state and dynamic response of the delayed-type PLL, derivator-based PLL and the complex-coefficient filter (CCF-PLL) under grid frequency...

  11. 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...... 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...

  12. 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

  13. A new type of single-phase five-level inverter

    Science.gov (United States)

    Xu, Zhi; Li, Shengnan; Qin, Risheng; Zhao, Yanhang

    2017-11-01

    At present, Neutral Point Clamped (NPC) multilevel inverter is widely applied in new energy field. However, it has some disadvantages including low utilization rate of direct current (DC) voltage source and the unbalance of neutral potential. Therefore, a new single-phase five level inverter is proposed in this paper. It has two stage structure, the former stage is equivalent to three level DC/DC converter, and the back stage uses H bridge to realize inverter. Compared with the original central clamp type inverter, the new five level inverter can improve the utilization of DC voltage, and realize the neutral point potential balance with hysteresis comparator.

  14. Single-phase cadmium telluride thin films deposited by electroless electrodeposition

    International Nuclear Information System (INIS)

    Khrypunov, G.; Klochko, N.; Lyubov, V.; Li, T.; Volkova, N.

    2010-01-01

    Full text : Today cadmium telluride (CdTe) is a leading base material for the fabrication of thin film solar cells. Equally with the creation of traditional thin film photovoltaic devices on the base of CdTe in recent years several approaches have been investigated to develop solar cells with extremely thin (80-500 nm) CdTe absorber (so-called ηE(eta)-solar cells) that offer the potential to reduce recombination losses in the base layers and thus use low cost materials. Until today the CdTe depositions for the η-solar cells manufacture were performed by vapour phase epitaxy under dynamical vacuum at working temperature 750 degrees Celsium or by electrodeposition in the special electrochemical cell equipped with the potentiostat. Development research of simple and inexpensive method for obtaining of the single-phase stoichiometric cadmium telluride films has required an improvement of the electroless electrodeposition technique, which theretofore was characterized by some disadvantages, namely, the CdTe films were polluted by free tellurium additions and the composition of the films was Cd:Te=55:45. So, for the showing up the synthesis of doped or stoichiometric cadmium telluride films conditions and in order to decide the problem of the deposition of single-phase CdTe layers it was researched the electrochemical processes going during electroless electrolysis in sulfate solutions with different acidities and CdSO 4 concentrations. Some film samples during deposition were illuminated by 500 W halogen lamp. Deposition time was 10-15 min. The phase composition and structure of the deposited films were determined by XRD-method, the average sizes of the crystalline grains in the films were estimated using Debye-Scherer formula. The transmittance spectra of the samples were measured by double beam spectrophotometer in the spectral range of 0.6-1.1 μm. Surface morphology of the films was researched by scanning electron microscopy. By means of analysis of the

  15. Effect of crystal orientation on conductivity and electron mobility in single-crystal alumina

    Science.gov (United States)

    Will, Fritz G.; Delorenzi, Horst G.; Janora, Kevin H.

    1992-01-01

    The electrical conductivity of high-purity, single-crystal alumina is determined parallel to and perpendicular to the c-axis. The mean conductivity of four samples of each orientation is a factor 3.3 higher parallel to the c-axis than perpendicular to it. The conductivity as a function of temperature is attributed to extrinsic electron conduction at temperatures from 400 to 900 C, and intrinsic semiconduction at temperatures from 900 to 1300 C. In the high-temperature regime, the slope on all eight specimens is 4.7 +/- 0.1 eV. Hence, the thermal bandgap at O K is 9.4 +/- 0.2 eV.

  16. Mobile Robot Self-Localization System Using Single Webcam Distance Measurement Technology in Indoor Environments

    Directory of Open Access Journals (Sweden)

    I-Hsum Li

    2014-01-01

    Full Text Available A single-webcam distance measurement technique for indoor robot localization is proposed in this paper. The proposed localization technique uses webcams that are available in an existing surveillance environment. The developed image-based distance measurement system (IBDMS and parallel lines distance measurement system (PLDMS have two merits. Firstly, only one webcam is required for estimating the distance. Secondly, the set-up of IBDMS and PLDMS is easy, which only one known-dimension rectangle pattern is needed, i.e., a ground tile. Some common and simple image processing techniques, i.e., background subtraction are used to capture the robot in real time. Thus, for the purposes of indoor robot localization, the proposed method does not need to use expensive high-resolution webcams and complicated pattern recognition methods but just few simple estimating formulas. From the experimental results, the proposed robot localization method is reliable and effective in an indoor environment.

  17. 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

  18. 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.

  19. Mobile Greenhouse Gas Flux Analyzer for Unmanned Aerial Vehicles, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In this SBIR Phase I effort, Los Gatos Research (LGR) proposes to develop a highly-accurate, lightweight, low-power gas analyzer for eddy flux covariance...

  20. 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

  1. MDCT of acute pancreatitis: Intraindividual comparison of single-phase versus dual-phase MDCT for initial assessment of acute pancreatitis using different CT scoring systems.

    Science.gov (United States)

    Avanesov, Maxim; Weinrich, Julius M; Kraus, Thomas; Derlin, Thorsten; Adam, Gerhard; Yamamura, Jin; Karul, Murat

    2016-11-01

    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. 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 ≥72h 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 ≥14days after initial evaluation. For effective dose estimation, volume CT dose index (CTDIvol) and dose length product (DLP) were recorded in all examinations. 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. An initial dual-phase abdominal CT after ≥72h 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 single-phase protocol. Copyright © 2016. Published by Elsevier

  2. 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...

  3. Novel Family of Single-Phase Modified Impedance-Source Buck-Boost Multilevel Inverters with Reduced Switch Count

    DEFF Research Database (Denmark)

    Husev, Oleksandr; Strzelecki, Ryszard; Blaabjerg, Frede

    2016-01-01

    This paper describes novel single-phase solutions with increased inverter voltage levels derived by means of a nonstandard inverter configuration and impedance source networks. Operation principles based on special modulation techniques are presented. Detailed component design guidelines along wi...

  4. 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)

  5. 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.

  6. 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)

  7. 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)

  8. 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.

  9. 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)

  10. Next Phase of Mobile Communications – LTE: The End of Fixed Broadband?

    OpenAIRE

    Eylert, Bernd; Eras, Martin; Zeh, Thomas

    2008-01-01

    With the introduction of the Internet in the early 90th years of the last century, broadband demand has increased tremendously. As ISDN was the modern technology at that time, which has had its correspondence in the mobile world in the GSM technology, DSL and its evolution has its correspondence in UMTS/3G and its evolution into HSPA (High Speed Packet Access) and soon in LTE (Long Term Evolution). With the globalisation of our industries business has changed during the last 15 years. Employe...

  11. 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...

  12. 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

  13. Spectrophotometric resonant measurement of wavelength phase dispersion on femtosecond laser cavities and single elements during their fabrication

    Science.gov (United States)

    Bukhshtab, Michael A.

    1996-02-01

    A spectrophotometric reflection technique and measurement results of wavelength phase dispersion on femtosecond laser cavities and distinct elements are reported. In contrast to novel frequency-domain and interferometric Fourier-transform methods, the proposed reflection-based measurement procedure maintains a notably high sensitivity while studying either cavities or single elements. Resolved phase spectrums are evaluated using a standard spectrophotometer with a single-beam reflection attachment.

  14. Muscle power failure in mobility-limited older adults: preserved single fiber function despite lower whole muscle size, quality and rate of neuromuscular activation.

    Science.gov (United States)

    Reid, Kieran F; Doros, Gheorghe; Clark, David J; Patten, Carolynn; Carabello, Robert J; Cloutier, Gregory J; Phillips, Edward M; Krivickas, Lisa S; Frontera, Walter R; Fielding, Roger A

    2012-06-01

    This study investigated the physiological and gender determinants of the age-related loss of muscle power in 31 healthy middle-aged adults (aged 40-55 years), 28 healthy older adults (70-85 years) and 34 mobility-limited older adults (70-85 years). We hypothesized that leg extensor muscle power would be significantly lower in mobility-limited elders relative to both healthy groups and sought to characterize the physiological mechanisms associated with the reduction of muscle power with aging. Computed tomography was utilized to assess mid-thigh body composition and calculate specific muscle power and strength. Surface electromyography was used to assess rate of neuromuscular activation and muscle biopsies were taken to evaluate single muscle fiber contractile properties. Peak muscle power, strength, muscle cross-sectional area, specific muscle power and rate of neuromuscular activation were significantly lower among mobility-limited elders compared to both healthy groups (P ≤ 0.05). Mobility-limited older participants had greater deposits of intermuscular adipose tissue (P mobility-limited elders relative to both healthy groups. Male gender was associated with greater decrements in peak and specific muscle power among mobility-limited participants. Impairments in the rate of neuromuscular activation and concomitant reductions in muscle quality are important physiological mechanisms contributing to muscle power deficits and mobility limitations. The dissociation between age-related changes at the whole muscle and single fiber level suggest that, even among older adults with overt mobility problems, contractile properties of surviving muscle fibers are preserved in an attempt to maintain overall muscle function.

  15. Gradient retention prediction of acid-base analytes in reversed phase liquid chromatography: a simplified approach for acetonitrile-water mobile phases.

    Science.gov (United States)

    Andrés, Axel; Rosés, Martí; Bosch, Elisabeth

    2014-11-28

    In previous work, a two-parameter model to predict chromatographic retention of ionizable analytes in gradient mode was proposed. However, the procedure required some previous experimental work to get a suitable description of the pKa change with the mobile phase composition. In the present study this previous experimental work has been simplified. The analyte pKa values have been calculated through equations whose coefficients vary depending on their functional group. Forced by this new approach, other simplifications regarding the retention of the totally neutral and totally ionized species also had to be performed. After the simplifications were applied, new prediction values were obtained and compared with the previously acquired experimental data. The simplified model gave pretty good predictions while saving a significant amount of time and resources. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. 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.

  17. Synthesis of single phase of CuTl-1234 thin films

    CERN Document Server

    Khan, N A; Ishida, K; Tateai, F; Kojima, T; Terada, N; Ihara, H

    1999-01-01

    Thin films of CuTl-1234 superconductor have been prepared for the first time using an amorphous phase epitaxy method (APE). In this method, an amorphous phase is sputtered from a target of stoichiometric composition CuBa/sub 2/Ca/sub 3/Cu/sub 4/O/sub x/. Thin films on the SrTiO/sub 3/ substrate after the thallium treatment are biaxially oriented. The XRD reflected a predominant single phase with c-axis 18.7 AA and pole figure measurements of (103) reflections showed a-axis oriented films with Delta phi =0.8 degrees . Resistivity measurements showed T/sub c/=113 K and preliminary J/sub c/ measurements manifested a current density of 1.0*10/sup 6/ A/cm (77 K, 0 T). The composition of films after EDX measurements is Cu /sub 0.3/Tl/sub 0.7/CuBa/sub 2/Ca/sub 3/Cu/sub 4/O/sub 12-y/. (8 refs).

  18. A two-phase inspection model for a single component system with three-stage degradation

    International Nuclear Information System (INIS)

    Wang, Huiying; Wang, Wenbin; Peng, Rui

    2017-01-01

    This paper presents a two-phase inspection schedule and an age-based replacement policy for a single plant item contingent on a three-stage degradation process. The two phase inspection schedule can be observed in practice. The three stages are defined as the normal working stage, low-grade defective stage and critical defective stage. When an inspection detects that an item is in the low-grade defective stage, we may delay the preventive replacement action if the time to the age-based replacement is less than or equal to a threshold level. However, if it is above this threshold level, the item will be replaced immediately. If the item is found in the critical defective stage, it is replaced immediately. A hybrid bee colony algorithm is developed to find the optimal solution for the proposed model which has multiple decision variables. A numerical example is conducted to show the efficiency of this algorithm, and simulations are conducted to verify the correctness of the model. - Highlights: • A two-phase inspection model is studied. • The failure process has three stages. • The delayed replacement is considered.

  19. Migration and clinical outcome of mobile-bearing versus fixed-bearing single-radius total knee arthroplasty : A randomized controlled trial

    NARCIS (Netherlands)

    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, E.R.; Nelissen, R.G.H.H.

    2018-01-01

    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

  20. Adsorption mechanism of acids and bases in reversed-phase liquid chromatography in weak buffered mobile phases designed for liquid chromatography/mass spectrometry.

    Science.gov (United States)

    Gritti, Fabrice; Guiochon, Georges

    2009-03-06

    The overloaded band profiles of five acido-basic compounds were measured, using weakly buffered mobile phases. Low buffer concentrations were selected to provide a better understanding of the band profiles recorded in LC/MS analyses, which are often carried out at low buffer concentrations. In this work, 10 microL samples of a 50 mM probe solution were injected into C(18)-bonded columns using a series of five buffered mobile phases at (SW)pH between 2 and 12. The retention times and the shapes of the bands were analyzed based on thermodynamic arguments. A new adsorption model that takes into account the simultaneous adsorption of the acidic and the basic species onto the endcapped adsorbent, predicts accurately the complex experimental profiles recorded. The adsorption mechanism of acido-basic compounds onto RPLC phases seems to be consistent with the following microscopic model. No matter whether the acid or the base is the neutral or the basic species, the neutral species adsorbs onto a large number of weak adsorption sites (their saturation capacity is several tens g/L and their equilibrium constant of the order of 0.1 L/g). In contrast, the ionic species adsorbs strongly onto fewer active sites (their saturation capacity is about 1g/L and their equilibrium constant of the order of a few L/g). From a microscopic point of view and in agreement with the adsorption isotherm of the compound measured by frontal analysis (FA) and with the results of Monte-Carlo calculations performed by Schure et al., the first type of adsorption sites are most likely located in between C(18)-bonded chains and the second type of adsorption sites are located deeper in contact with the silica surface. The injected concentration (50 mM) was too low to probe the weakest adsorption sites (saturation capacity of a few hundreds g/L with an equilibrium constant of one hundredth of L/g) that are located at the very interface between the C(18)-bonded layer and the bulk phase.

  1. Towards the Development of a Mobile Phonopneumogram: Automatic Breath-Phase Classification Using Smartphones.

    Science.gov (United States)

    Reyes, Bersain A; Reljin, Natasa; Kong, Youngsun; Nam, Yunyoung; Ha, Sangho; Chon, Ki H

    2016-09-01

    Correct labeling of breath phases is useful in the automatic analysis of respiratory sounds, where airflow or volume signals are commonly used as temporal reference. However, such signals are not always available. The development of a smartphone-based respiratory sound analysis system has received increased attention. In this study, we propose an optical approach that takes advantage of a smartphone's camera and provides a chest movement signal useful for classification of the breath phases when simultaneously recording tracheal sounds. Spirometer and smartphone-based signals were acquired from N = 13 healthy volunteers breathing at different frequencies, airflow and volume levels. We found that the smartphone-acquired chest movement signal was highly correlated with reference volume (ρ = 0.960 ± 0.025, mean ± SD). A simple linear regression on the chest signal was used to label the breath phases according to the slope between consecutive onsets. 100% accuracy was found for the classification of the analyzed breath phases. We found that the proposed classification scheme can be used to correctly classify breath phases in more challenging breathing patterns, such as those that include non-breath events like swallowing, talking, and coughing, and alternating or irregular breathing. These results show the feasibility of developing a portable and inexpensive phonopneumogram for the analysis of respiratory sounds based on smartphones.

  2. Single-phase and two-phase anaerobic digestion of fruit and vegetable waste: Comparison of start-up, reactor stability and process performance

    Energy Technology Data Exchange (ETDEWEB)

    Ganesh, Rangaraj [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France); Torrijos, Michel, E-mail: michel.torrijos@supagro.inra.fr [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France); Sousbie, Philippe [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France); Lugardon, Aurelien [Naskeo Environnment, 52 rue Paul Vaillant Couturier, F-92240 Malakoff (France); Steyer, Jean Philippe; Delgenes, Jean Philippe [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France)

    2014-05-01

    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{sup 3} CH{sub 4}/kg VS and 83% VS removal. • Substrate solubilization was high in acidification conditions at 7.0 kg VS/m{sup 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{sup 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{sup 3} CH{sub 4}/kg VS fed and VS removal of 83%. The TPAR shifted to acidification mode at an OLR of 10.0 kg VS/m{sup 3} d and then achieved stable performance at 7.0 kg VS/m{sup 3} d and pH 5.5–6.2, with very high substrate solubilization rate and a methane yield of 0.30 m{sup 3} CH{sub 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

  3. An Islanding Detection Method by Using Frequency Positive Feedback Based on FLL for Single-Phase Microgrid

    DEFF Research Database (Denmark)

    Sun, Qinfei; Guerrero, Josep M.; Jing, Tianjun

    2017-01-01

    An active islanding detection method based on Frequency-Locked Loop (FLL) for constant power controlled inverter in single-phase microgrid is proposed. This method generates a phase shift comparing the instantaneous frequency obtained from FLL unit with the nominal frequency to modify the reference...

  4. A comparative study of microstructure and mechanical properties between friction stir welded single and double phase brass alloys

    Energy Technology Data Exchange (ETDEWEB)

    Heidarzadeh, A.; Saeid, T., E-mail: saeid@sut.ac.ir

    2016-01-01

    This study was done in order to compare the microstructure and mechanical properties of friction stir welded single and double phase brass alloys. The microstructure of the joints were examined using optical microscope, scanning electron microscope (SEM), scanning transmission electron microscope (STEM), and X-ray diffraction. Furthermore, tensile test and fractography were applied to evaluate the mechanical properties of the joints. The results showed that the grain size of the stir zone in the double phase joint was smaller than that of the single phase alloy. In comparison with base metals, both of the joints contained high density of dislocations with a qualitatively similar texture. However, the dislocation density of the double phase joint was somewhat lower than that of the single phase one. Moreover, the joints had higher tensile strength, lower elongation and less ductile fracture compared to their base metals due to their finer grain size and higher dislocation density. The double phase joint had higher strength and lower elongation than single phase joint due to the effect of the second phase.

  5. Energy production from distillery wastewater using single and double-phase upflow anaerobic sludge blanket (UASB) reactor

    Energy Technology Data Exchange (ETDEWEB)

    Muyodi, F.J.; Rubindamayugi, M.S.T. [Univ. of Dar es Salaam, Applied Microbiology Unit (Tanzania, United Republic of)

    1997-12-31

    A Single-phase (SP) and Double-phase (DP) Upflow Anaerobic Sludge Blanket (UASB) reactors treating distillery wastewater were operated in parallel. The DP UASB reactor showed better performance than the SP UASB reactor in terms of maximum methane production rate, methane content and Chemical Oxygen Demand (COD) removal efficiency. (au) 20 refs.

  6. Mobile phone base stations and adverse health effects: phase 1 of a population-based, cross-sectional study in Germany

    DEFF Research Database (Denmark)

    Blettner, M; Schlehofer, B; Breckenkamp, J

    2009-01-01

    OBJECTIVE: The aim of this first phase of a cross-sectional study from Germany was to investigate whether proximity of residence to mobile phone base stations as well as risk perception is associated with health complaints. METHODS: The researchers conducted a population-based, multi-phase, cross......-sectional study within the context of a large panel survey regularly carried out by a private research institute in Germany. In the initial phase, reported on in this paper, 30,047 persons from a total of 51,444 who took part in the nationwide survey also answered questions on how mobile phone base stations...... affected their health. A list of 38 health complaints was used. A multiple linear regression model was used to identify predictors of health complaints including proximity of residence to mobile phone base stations and risk perception. RESULTS: Of the 30,047 participants (response rate 58.6%), 18...

  7. Identification of phase-II metabolites of flavonoids by liquid chromatography-ion-mobility spectrometry-mass spectrometry.

    Science.gov (United States)

    Chalet, Clément; Hollebrands, Boudewijn; Janssen, Hans-Gerd; Augustijns, Patrick; Duchateau, Guus

    2018-01-01

    Flavonoids are a class of natural compounds with a broad range of potentially beneficial health properties. They are subjected to an extensive intestinal phase-II metabolism, i.e., conjugation to glucuronic acid, sulfate, and methyl groups. Flavonoids and their metabolites can interact with drug transporters and thus interfere with drug absorption, causing food-drug interactions. The site of metabolism plays a key role in the activity, but the identification of the various metabolites remains a challenge. Here, we developed an analytical method to identify the phase-II metabolites of structurally similar flavonoids. We used liquid chromatography-ion-mobility spectrometry-mass spectrometry (LC-IMS-MS) analysis to identify phase-II metabolites of flavonols, flavones, and catechins produced by HT29 cells. We showed that IMS could bring valuable structural information on the different positional isomers of the flavonols and flavones. The position of the glucuronide moiety had a strong influence on the collision cross section (CCS) of the metabolites, with only minor contribution of hydroxyl and methyl moieties. For the catechins, fragmentation data obtained from MS/MS analysis appeared more useful than IMS to determine the structure of the metabolites, mostly due to the high number of metabolites formed. Nevertheless, CCS information as a molecular fingerprint proved to be useful to identify peaks from complex mixtures. LC-IMS-MS thus appears as a valuable tool for the identification of phase-II metabolites of flavonoids. Graphical abstract Structural identification of phase-II metabolites of flavonoids using LC-IMS-MS.

  8. Contaminants migration in the soil: the influence of transfer between the mobile and stationary phases

    International Nuclear Information System (INIS)

    Moreira, R.M.; Sabino, C.S.V.; Macedo, W.A.

    1996-01-01

    Three transport mechanisms control the contaminant migration in saturated soils: advection, diffusion and interchanges between liquid and solid phases. These interchanges define the retention by the soil and the contaminant delay related to the liquid phase flow. Therefore, the knowledge of the adsorption/desorption characteristics of the solute in solid surfaces is fundamental for the evaluation of toxic agent releases to the compartment soil. This communication reports the study which is being performed by the Centro de Desenvolvimento da Tecnologia Nuclear (CDTN) in this area, particularly with cesium and mercury by using X-ray absorption spectroscopy for contaminants migration

  9. Performance Evaluation of the Single-Phase Split-Source Inverter Using an Alternative DC-AC Configuration

    DEFF Research Database (Denmark)

    Abdelhakim, Ahmed; Mattavelli, Paolo; Davari, Pooya

    2018-01-01

    This paper investigates and evaluates the performance of a single-phase split-source inverter (SSI), where an alternative unidirectional dc-ac configuration is used. Such configuration is utilized in order to use two common-cathode diodes in a single-device instead of using two separate diodes, r...

  10. Safe-commutation principle for direct single-phase AC-AC converters for use in audio power amplification

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2004-01-01

    This paper presents an alternative safe commutation principle for a single phase bidirectional bridge, for use in the new generation of direct single-stage AC-AC audio power amplifiers. As compared with the bridge commutation with load current or source voltage sensing, in this approach...

  11. Single phase flow pressure drop and heat transfer in rectangular metallic microchannels

    International Nuclear Information System (INIS)

    Sahar, Amirah M.; Özdemir, Mehmed R.; Fayyadh, Ekhlas M.; Wissink, Jan; Mahmoud, Mohamed M.; Karayiannis, Tassos G.

    2016-01-01

    Numerical simulations were performed using Fluent 14.5 to investigate single phase flow and conjugate heat transfer in copper rectangular microchannels. Two different configurations were simulated: (1) single channel with hydraulic diameter of 0.561 mm and (2) multichannel configuration consisting of inlet and outlet manifolds and 25 channels with hydraulic diameter of 0.409 mm. In the single channel configuration, four numerical models were investigated namely, 2D thin-wall, 3D thin-wall (heated from the bottom), 3D thin-wall (three side heated) and 3D full conjugate models. In the multichannel configuration, only 3D full conjugate model was used. The simulation results of the single channel configuration were validated using experimental data of water as a test fluid while the results of the multichannel configuration were validated using experimental data of R134a refrigerant. In the multichannel configuration, flow distribution among the channels was also investigated. The 3D thin-wall model simulation was conducted at thermal boundary conditions similar to those assumed in the experimental data reduction (uniform heat flux) and showed excellent agreement with the experimental data. However, the results of the 3D full conjugate model demonstrated that there is a significant conjugate effect and the heat flux is not uniformly distributed along the channel resulting in significant deviation compared to the experimental data (more than 50%). Also, the results demonstrated that there is a significant difference between the 3D thin-wall and full conjugate models. The simulation of the multichannel configuration with an inlet manifold having gradual decrease in cross sectional area achieved very reasonable uniform flow distribution among the channels which will provide uniform heat transfer rates across the base of the microchannels.

  12. Environmental mobility of cobalt-Influence of solid phase characteristics and groundwater chemistry

    International Nuclear Information System (INIS)

    Payne, T.E.; Itakura, T.; Comarmond, M.J.; Harrison, J.J.

    2009-01-01

    The adsorption of cobalt on samples from a potential waste repository site in an arid region was investigated in batch experiments, as a function of various solution phase parameters including the pH and ionic strength. The samples were characterized using a range of techniques, including BET surface area measurements, total clay content and quantitative X-ray diffraction. The statistical relationships between the measured cobalt distribution coefficients (K d values) and the solid and liquid phase characteristics were assessed. The sorption of cobalt increased with the pH of the aqueous phase. In experiments with a fixed pH value, the measured K d values were strongly correlated to the BET surface area, but not to the amount of individual clay minerals (illite, kaolinite or smectite). A further set of sorption experiments was undertaken with two samples of distinctive mineralogy and surface area, and consequently different sorption properties. A simple surface complexation model (SCM) that conceptualized the surface sites as having equivalent sorption properties to amorphous Fe-oxide was moderately successful in explaining the pH dependence of the sorption data on these samples. Two different methods of quantifying the input parameters for the SCM were assessed. While a full SCM for cobalt sorption on these complex environmental substrates is not yet possible, the basic applicability and predictive capability of this type of modeling is demonstrated. A principal requirement to further develop the modeling approach is adequate models for cobalt sorption on component mineral phases of complex environmental sorbents.

  13. Gas-Phase Enrichment of Multiply Charged Peptide Ions by Differential Ion Mobility Extend the Comprehensiveness of SUMO Proteome Analyses.

    Science.gov (United States)

    Pfammatter, Sibylle; Bonneil, Eric; McManus, Francis P; Thibault, Pierre

    2018-04-05

    The small ubiquitin-like modifier (SUMO) is a member of the family of ubiquitin-like modifiers (UBLs) and is involved in important cellular processes, including DNA damage response, meiosis and cellular trafficking. The large-scale identification of SUMO peptides in a site-specific manner is challenging not only because of the low abundance and dynamic nature of this modification, but also due to the branched structure of the corresponding peptides that further complicate their identification using conventional search engines. Here, we exploited the unusual structure of SUMO peptides to facilitate their separation by high-field asymmetric waveform ion mobility spectrometry (FAIMS) and increase the coverage of SUMO proteome analysis. Upon trypsin digestion, branched peptides contain a SUMO remnant side chain and predominantly form triply protonated ions that facilitate their gas-phase separation using FAIMS. We evaluated the mobility characteristics of synthetic SUMO peptides and further demonstrated the application of FAIMS to profile the changes in protein SUMOylation of HEK293 cells following heat shock, a condition known to affect this modification. FAIMS typically provided a 10-fold improvement of detection limit of SUMO peptides, and enabled a 36% increase in SUMO proteome coverage compared to the same LC-MS/MS analyses performed without FAIMS. Graphical Abstract ᅟ.

  14. 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 terms of gain and efficiency. This property has been achieved by applying a new slot-loop resonators. The proposed antenna is designed to operate at 21-23.5 GHz and has a same performance for different values of dielectric constant and loss tangent. It has high-gain, high-efficiency radiation beams...... 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....

  15. Intelligent mobile sensor system for drum inspection and monitoring: Phase 1

    International Nuclear Information System (INIS)

    1993-06-01

    The objective of this project was to develop an operational system for monitoring and inspection activities for waste storage facility operations at several DOE sites. Specifically, the product of this effort is a robotic device with enhanced intelligence and maneuverability capable of conducting routine inspection of stored waste drums. The device is capable of operating in narrow aisles and interpolating the free aisle space between rows of stacked drums. The system has an integrated sensor suite for leak detection, and is interfaced with a site database both for inspection planning and for data correlation, updating, and report generation. The system is capable of departing on an assigned mission, collecting required data, recording which positions of its mission had to be aborted or modified due to environmental constraints, and reporting back when the mission is complete. Successful identification of more than 90% of all drum defects has been demonstrated in a high fidelity waste storage facility mockup. Identified anomalies included rust spots, rust streaks, areas of corrosion, dents, and tilted drums. All drums were positively identified and correlated with the site database. This development effort is separated into three phases of which phase one is now complete. The first phase has demonstrated an integrated system for monitoring and inspection activities for waste storage facility operations. This demonstration system was quickly fielded and evaluated by leveraging technologies developed from previous NASA and DARPA contracts and internal research. The second phase will demonstrate a prototype system appropriate for operational use in an actual storage facility. The prototype provides an integrated design that considers operational requirements, hardware costs, maintenance, safety, and robustness. The final phase will demonstrate commercial viability using the prototype vehicle in a pilot waste operations and inspection project

  16. Length distribution of single-walled carbon nanotubes in aqueous suspension measured by electrospray differential mobility analysis.

    Science.gov (United States)

    Pease, Leonard F; Tsai, De-Hao; Fagan, Jeffery A; Bauer, Barry J; Zangmeister, Rebecca A; Tarlov, Michael J; Zachariah, Michael R

    2009-12-01

    The first characterization of the length distribution of single-walled carbon nanotubes (SWCNT) dispersed in a liquid by electrospray differential mobility analysis (ES-DMA) is presented. Although an understanding of geometric properties of SWCNTs, including length, diameter, aspect ratio, and chirality, is essential for commercial applications, rapid characterization of nanotube length distributions remains challenging. Here the use of ES-DMA to obtain length distributions of DNA-wrapped SWCNTs dispersed in aqueous solutions is demonstrated. Lengths measured by ES-DMA compare favorably with those obtained from multiangle light scattering, dynamic light scattering, field flow fractionation with UV/vis detection, and atomic force microscopy, validating ES-DMA as a technique to measure SWCNTs of <250 nm in length. The nanotubes are previously purified and dispersed by wrapping with oligomeric DNA in aqueous solution and centrifuging to remove bundles and amorphous carbon. These dispersions are particularly attractive due to their amenability to bulk processing, ease of storage, high concentration, compatibility with biological and high-throughput manufacturing environments, and for their potential applications ranging from electronics and hydrogen-storage vessels to anticancer agents.

  17. Comprehensive Gas-Phase Peptide Ion Structure Studies Using Ion Mobility Techniques: Part 2. Gas-Phase Hydrogen/Deuterium Exchange for Ion Population Estimation

    Science.gov (United States)

    Khakinejad, Mahdiar; Ghassabi Kondalaji, Samaneh; Tafreshian, Amirmahdi; Valentine, Stephen J.

    2017-05-01

    Gas-phase hydrogen/deuterium exchange (HDX) using D2O reagent and collision cross-section (CCS) measurements are utilized to monitor the ion conformers of the model peptide acetyl-PAAAAKAAAAKAAAAKAAAAK. The measurements are carried out on a home-built ion mobility instrument coupled to a linear ion trap mass spectrometer containing electron transfer dissociation (ETD) capabilities. ETD is utilized to obtain per-residue deuterium uptake data for select ion conformers, and a new algorithm is presented for interpreting the HDX data. Using molecular dynamics (MD) production data and a hydrogen accessibility scoring (HAS)-number of effective collisions (NEC) model, hypothetical HDX behavior is attributed to various in-silico candidate (CCS match) structures. The HAS-NEC model is applied to all candidate structures, and non-negative linear regression is employed to determine structure contributions resulting in the best match to deuterium uptake. The accuracy of the HAS-NEC model is tested with the comparison of predicted and experimental isotopic envelopes for several of the observed c-ions. It is proposed that gas-phase HDX can be utilized effectively as a second criterion (after CCS matching) for filtering suitable MD candidate structures. In this study, the second step of structure elucidation, 13 nominal structures were selected (from a pool of 300 candidate structures) and each with a population contribution proposed for these ions.

  18. Comparison of iso-eluotropic mobile phases at different temperatures for the separation of triacylglycerols in Non-Aqueous Reversed Phase Liquid Chromatography.

    Science.gov (United States)

    Hmida, Dorra; Abderrabba, Manef; Tchapla, Alain; Héron, Sylvie; Moussa, Fathi

    2015-05-15

    Triacylglycerols (TAGs) are a large class of neutral lipids that naturally occur in both plant and animal oils and fats. Their analyses in Non-Aqueous Reversed Phase Liquid Chromatography (NARP) require a mixture of weak solvent (mostly acetonitrile) and strong solvent. In the present work, we have established eluotropic solvent strength scale of several binary mobile phases on C18 bonded silica at different temperatures (acetonitrile/methylene chloride, acetonitrile/acetone, acetonitrile/ethyl acetate, acetonitrile/propan-2-ol, and acetonitrile/butan-1-ol at 25°C, 43°C, 63°C and 85°C); it is based on the methylene selectivity and the use of homologous series. We show that this scale is well suited to the TAGs analysis. The analysis of nine seed oils (Aleurites fordii, Calophyllum inophyllum, Glycina max, Olea europea, Orbignya olifeira, Pinus koraiensis, Pistacia lentiscus, Punica granatum and Ribes nigrum) in iso-eluotropic conditions leads to propose unambiguously the couple MeCN/BuOH at 25°C as the best system to separate TAGs. The use of butanol, as strong solvent, provides very good TAGs congeners separations and avoids the use of chlorinated solvents which gave to this day the best separations. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Dielectric behavior and phase transition in [111]-oriented PIN–PMN–PT single crystals under dc bias

    Directory of Open Access Journals (Sweden)

    Yuhui Wan

    2014-01-01

    Full Text Available Temperature and electric field dependences of the dielectric behavior and phase transition for [111]-oriented 0.23PIN–0.52PMN–0.25PT (PIN-PMN–0.25PT and 0.24PIN–0.43PMN–0.33PT (PIN–PMN–0.33PT single crystals were investigated over a temperature range from -100°C to 250°C using field-heating (FH dielectric measurements. The transition phenomenon from ferroelectric microdomain to macrodomain was found in rhombohedra (R phase region in the single crystals under dc bias. This transition temperature Tf of micro-to-macrodomain is sensitive to dc bias and move quickly to lower temperature with increasing dc bias. The phase transition temperatures in the two single crystals shift toward high temperature and the dielectric permittivities at the phase transition temperature decrease with increasing dc bias. Especially, the phase transition peaks are gradually broad in PIN–PMN–0.33PT single crystal with the increasing dc bias. Effects of dc bias on the dielectric behavior and phase transition in PIN–PMN–PT single crystals are discussed.

  20. High mobility single-crystalline-like GaAs thin films on inexpensive flexible metal substrates by metal-organic chemical vapor deposition

    International Nuclear Information System (INIS)

    Dutta, P.; Rathi, M.; Gao, Y.; Yao, Y.; Selvamanickam, V.; Zheng, N.; Ahrenkiel, P.; Martinez, J.

    2014-01-01

    We demonstrate heteroepitaxial growth of single-crystalline-like n and p-type doped GaAs thin films on inexpensive, flexible, and light-weight metal foils by metal-organic chemical vapor deposition. Single-crystalline-like Ge thin film on biaxially textured templates made by ion beam assisted deposition on metal foil served as the epitaxy enabling substrate for GaAs growth. The GaAs films exhibited strong (004) preferred orientation, sharp in-plane texture, low grain misorientation, strong photoluminescence, and a defect density of ∼10 7  cm −2 . Furthermore, the GaAs films exhibited hole and electron mobilities as high as 66 and 300 cm 2 /V-s, respectively. High mobility single-crystalline-like GaAs thin films on inexpensive metal substrates can pave the path for roll-to-roll manufacturing of flexible III-V solar cells for the mainstream photovoltaics market.

  1. Energetics analysis of interstitial loops in single-phase concentrated solid-solution alloys

    Science.gov (United States)

    Wang, Xin-Xin; Niu, Liang-Liang; Wang, Shaoqing

    2018-04-01

    Systematic energetics analysis on the shape preference, relative stability and radiation-induced segregation of interstitial loops in nickel-containing single-phase concentrated solid-solution alloys have been conducted using atomistic simulations. It is shown that the perfect loops prefer rhombus shape for its low potential energy, while the Frank faulted loops favor ellipse for its low potential energy and the possible large configurational entropy. The decrease of stacking fault energy with increasing compositional complexity provides the energetic driving force for the formation of faulted loops, which, in conjunction with the kinetic factors, explains the experimental observation that the fraction of faulted loops rises with increasing compositional complexity. Notably, the kinetics is primarily responsible for the absence of faulted loops in nickel-cobalt with a very low stacking fault energy. We further demonstrate that the simultaneous nickel enrichment and iron/chromium depletion on interstitial loops can be fully accounted for by their energetics.

  2. On Thermodynamics Problems in the Single-Phase-Lagging Heat Conduction Model

    Directory of Open Access Journals (Sweden)

    Shu-Nan Li

    2016-11-01

    Full Text Available Thermodynamics problems for the single-phase-lagging (SPL model have not been much studied. In this paper, the violation of the second law of thermodynamics by the SPL model is studied from two perspectives, which are the negative entropy production rate and breaking equilibrium spontaneously. The methods for the SPL model to avoid the negative entropy production rate are proposed, which are extended irreversible thermodynamics and the thermal relaxation time. Modifying the entropy production rate positive or zero is not enough to avoid the violation of the second law of thermodynamics for the SPL model, because the SPL model could cause breaking equilibrium spontaneously in some special circumstances. As comparison, it is shown that Fourier’s law and the CV model cannot break equilibrium spontaneously by analyzing mathematical energy integral.

  3. Single-drop liquid phase microextraction accelerated by surface acoustic wave.

    Science.gov (United States)

    Zhang, Anliang; Zha, Yan

    2013-03-01

    A single-drop liquid phase microextraction method is presented, in which surface acoustic wave (SAW) is used for accelerating extraction speed. A pair of interdigital transducers with 27.5 MHz center frequency is fabricated on a 128° yx-LiNbO3 substrate. A radio frequency signal is applied to one of interdigital transducers to excite SAW. Plastic straw is filled with PDMS, leaving 1 mL for holding sample solution. Plastic straw with sample solution droplet is then dipping into extractant, into which SAW is radiated. Mass transportation from sample solution to extractant drop is accelerated due to acoustic streaming, and extraction time is decreased. An ionic liquid and an acid green-25 solution are used for extraction experiments. Results show that the extraction process is almost finished within 2 min, and extraction speed is increased with radio frequency signal power. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Single-phase pump model for analysis of LMFBR heat transport systems

    International Nuclear Information System (INIS)

    Madni, I.K.; Cazzoli, E.

    1978-05-01

    A single-phase pump model for transient and steady-state analysis of LMFBR heat transport systems is presented. Fundamental equations of the model are angular momentum balance to determine transient impeller speed and mass balance (including thermal expansion effects) to determine the level of sodium in the pump tank. Pump characteristics are modeled by homologous head and torque relations. All regions of pump operation are represented with reverse rotation allowed. The model also includes option for enthalpy rise calculations and pony motor operation. During steady state, the pump operating speed is determined by matching required head with total load in the circuit. Calculated transient results are presented for pump coastdown and double-ended pipe break accidents. The report examines the influence of frictional torque and specific speed on predicted response for the pump coastdown to natural circulation transient. The results for a double-ended pipe break accident indicate the necessity of including all regions of operation for pump characteristics

  5. Single-phase sodium pump model for LMFBR thermal-hydraulic analysis

    International Nuclear Information System (INIS)

    Madni, I.K.; Cazzoli, E.G.; Agrawal, A.K.

    1979-01-01

    A single-phase, homologous pump model has been developed for simulation of safety-related transients in LMFBR systems. Pump characteristics are modeled by homologous head and torque relations encompassing all regimes of operation. These relations were derived from independent model test results with a centrifugal pump of specific speed equal to 35 (SI units) or 1800 (gpm units), and are used to analyze the steady-state and transient behavior of sodium pumps in a number of LMFBR plants. Characteristic coefficients for the polynomials in all operational regimes are provided in a tabular form. The speed and flow dependence of head is included through solutions of the impeller and coolant dynamic equations. Results show the model to yield excellent agreement with experimental data in sodium for the FFTF prototype pump, and with vendor calculations for the CRBR pump. A sample pipe rupture calculation is also performed to demonstrate the necessity for modeling the complete pump characteristics

  6. Exploration of the Berry phase interference in a single-molecule magnets of trigonal symmetry

    Science.gov (United States)

    Quddusi, H. M.; Liu, J.; Feng, P. L.; Del Barco, E.; Hill, S.; Hendrickson, D. N.

    2012-02-01

    The quantum behavior of single-molecule magnets (SMM) is mainly governed by their molecular composition and crystallographic symmetries, thus playing an essential role in the tunneling dynamics. We present low temperature magnetometry measurements on a trigonal symmetric, low nuclearity Mn3 SMM. The experiments are designed to explore the behavior of the tunnel splittings within the transverse field magnitude/direction phase space, by applying a transverse field (0-1 T) along different directions within the hard anisotropy plane of the molecules. The expected quantum interference pattern can be understood as an outcome of a competition between different intramolecular magnetic interactions. A multi-spin description using non-collinear zero-field splitting tensors and intra molecular dipolar interactions between the manganese ions is employed to explain the symmetry patterns.

  7. Analytical Determining Of The Steinmetz Equivalent Diagram Elements Of Single-Phase Transformer

    Directory of Open Access Journals (Sweden)

    T. Aly Saandy

    2015-08-01

    Full Text Available This article presents to an analytical calculation methodology of the Steinmetz Equivalent Diagram Elements applied to the prediction of Eddy current loss in a single-phase transformer. Based on the electrical circuit theory the active and reactive powers consumed by the core are expressed analytically in function of the electromagnetic parameters as resistivity permeability and the geometrical dimensions of the core. The proposed modeling approach is established with the duality parallel series. The equivalent diagram elements empirically determined by Steinmetz are analytically expressed using the expressions of the no loaded transformer consumptions. To verify the relevance of the model validations both by simulations with different powers and measurements were carried out to determine the resistance and reactance of the core. The obtained results are in good agreement with the theoretical approach and the practical results.

  8. Analytical Modeling Of The Steinmetz Coefficient For Single-Phase Transformer Eddy Current Loss Prediction

    Directory of Open Access Journals (Sweden)

    T. Aly Saandy

    2015-08-01

    Full Text Available Abstract This article presents to an analytical calculation methodology of the Steinmetz coefficient applied to the prediction of Eddy current loss in a single-phase transformer. Based on the electrical circuit theory the active power consumed by the core is expressed analytically in function of the electrical parameters as resistivity and the geometrical dimensions of the core. The proposed modeling approach is established with the duality parallel series. The required coefficient is identified from the empirical Steinmetz data based on the experimented active power expression. To verify the relevance of the model validations both by simulations with two in two different frequencies and measurements were carried out. The obtained results are in good agreement with the theoretical approach and the practical results.

  9. 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...... systems due to anti-islanding protection may trigger grid disturbances. Thus, standards featuring with ancillary services for the next generation PV systems are under a revision in some countries. The future PV systems have to provide a full range of services as what the conventional power plants do, e...... 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...

  10. Modelling and Simulation of Single-Phase Series Active Compensator for Power Quality Improvement

    Science.gov (United States)

    Verma, Arun Kumar; Mathuria, Kirti; Singh, Bhim; Bhuvaneshwari, G.

    2017-10-01

    A single-phase active series compensator is proposed in this work to reduce harmonic currents at the ac mains and to regulate the dc link voltage of a diode bridge rectifier (DBR) that acts as the front end converter for a voltage source inverter feeding an ac motor. This ac motor drive is used in any of the domestic, commercial or industrial appliances. Under fluctuating ac mains voltages, the dc link voltage of the DBR depicts wide variations and hence the ac motor is used at reduced rating as compared to its name-plate rating. The active series compensator proposed here provides dual functions of improving the power quality at the ac mains and regulating the dc link voltage thus averting the need for derating of the ac motor.

  11. Capsule-like voids in SiC single crystal: Phase contrast imaging and computer simulations

    Directory of Open Access Journals (Sweden)

    V. G. Kohn

    2014-09-01

    Full Text Available The results of observation of capsule-like voids in silicon carbide (6H-SiC single crystal by means of a phase contrast imaging technique with synchrotron radiation at the Pohang Light Source as well as computer simulations of such images are presented. A pink beam and a monochromated beam were used. The latter gives more pronounced images but they still are smoothed due to a finite detector resolution and the spatial coherence of the beam. Sizes and a structure of far field images are different from these of the objects. The computer simulations allow us to reproduce a shape and a size of the capsule-like void.

  12. 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...... like what the conventional power plants do today in the grid regulation participation. Requirements of ancillary services like Low-Voltage Ride-Through (LVRT) associated with reactive current injection and voltage support through reactive power control, have been in effectiveness in some countries, e...... 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...

  13. 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

    . 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 the light of this, Reactive Power Injection (RPI) strategies for single-phase PV systems are explored in this paper. The RPI...... like what the conventional power plants do today in the grid regulation participation. Requirements of ancillary services like Low-Voltage Ride-Through (LVRT) associated with reactive current injection and voltage support through reactive power control, have been in effectiveness in some countries...... 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 thermal optimized control strategy...

  14. Quantitative X-ray dark-field and phase tomography using single directional speckle scanning technique

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongchang, E-mail: hongchang.wang@diamond.ac.uk; Kashyap, Yogesh; Sawhney, Kawal [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

    2016-03-21

    X-ray dark-field contrast tomography can provide important supplementary information inside a sample to the conventional absorption tomography. Recently, the X-ray speckle based technique has been proposed to provide qualitative two-dimensional dark-field imaging with a simple experimental arrangement. In this letter, we deduce a relationship between the second moment of scattering angle distribution and cross-correlation degradation of speckle and establish a quantitative basis of X-ray dark-field tomography using single directional speckle scanning technique. In addition, the phase contrast images can be simultaneously retrieved permitting tomographic reconstruction, which yields enhanced contrast in weakly absorbing materials. Such complementary tomography technique can allow systematic investigation of complex samples containing both soft and hard materials.

  15. Condition monitoring of shaft of single-phase induction motor using optical sensor

    Science.gov (United States)

    Fulzele, Asmita G.; Arajpure, V. G.; Holay, P. P.; Patil, N. M.

    2012-05-01

    Transmission type of optical technique is developed to sense the condition of rotating shafts from a distance. A parallel laser beam is passed tangential over the surface of rotating shaft of a single phase induction motor and its flickering shadow is received on a photo sensor. Variations in sensor voltage output are observed on a digital storage oscilloscope. It is demonstrated that this signal carries information about shaft defects like miss alignment, play and impacts in bearings along with surface deformities. Mathematical model of signals corresponding to these shaft defects is developed. During the development and testing of the sensor, effects of reflections are investigated, sensing phenomenon is simulated, frequency response of the sensor is obtained and its performance is compared with conventional accelerometer.

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

    KAUST Repository

    Wang, Yi

    2017-01-25

    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 and problem scales are designed to examine the fidelity and robustness of the model. High precision (relative deviation 1.0 x 10(-4)% similar to 2.3 x 10(-1)%) and large acceleration (speed-up 880 similar to 98454 times) of POD model are found in these cases. Moreover, the computational time of POD model is quite insensitive to the complexity of problems. These results indicate POD model is especially suitable for large-scale complex problems in engineering.

  17. Broadband single-phase hyperbolic elastic metamaterials for super-resolution imaging.

    Science.gov (United States)

    Dong, Hao-Wen; Zhao, Sheng-Dong; Wang, Yue-Sheng; Zhang, Chuanzeng

    2018-02-02

    Hyperbolic metamaterials, the highly anisotropic subwavelength media, immensely widen the engineering feasibilities for wave manipulation. However, limited by the empirical structural topologies, the reported hyperbolic elastic metamaterials (HEMMs) suffer from the limitations of the relatively narrow frequency width, inflexible adjustable operating subwavelength scale and difficulty to further improve the imaging resolution. Here, we show an inverse-design strategy for HEMMs by topology optimization. We design broadband single-phase HEMMs supporting multipolar resonances at different prescribed deep-subwavelength scales, and demonstrate the super-resolution imaging for longitudinal waves. Benefiting from the extreme enhancement of the evanescent waves, an optimized HEMM at an ultra-low frequency can yield an imaging resolution of ~λ/64, representing the record in the field of elastic metamaterials. The present research provides a novel and general design methodology for exploring the HEMMs with unrevealed mechanisms and guides the ultrasonography and general biomedical applications.

  18. Pressure drop characteristics of single-phase flow in vertical rolling pipes

    International Nuclear Information System (INIS)

    Cao Xiaxin; Yan Changqi; Sun Licheng; Sun Zhongning

    2007-01-01

    Experimental studies of single-phase pressure drop in rolling pipes were carried out. The inside diameters of three pipes which were fixed on the rolling platform were 15 mm, 25 mm, and 34.5 mm respectively, the rolling periods of the rolling platform could be set as 5s, 10s, 15s, and rolling angles of the rolling platform were 10 degree and 20 degree. The experimental results showed that the frictional factor periodically fluctuated with the time variable, and its amplitude was obviously affected by the change of Reynolds number and pipe diameters. The amplitude and average value of frictional factor both decreased with the increase of Re number, but the bigger the tube diameter was, the larger the amplitude of frictional factor was. At any moment, the transient frictional factor increased with the increase of rolling period. However, the effect of changing rolling angles on the frictional factor was not obvious. (authors)

  19. Rotor Design for an Efficient Single-Phase Induction Motor for Refrigerator Compressors

    Directory of Open Access Journals (Sweden)

    Hyun-Jin Ahn

    2016-03-01

    Full Text Available This article describes a rotor making technology for the production of high-efficiency single-phase induction motors (SPIMs to be used in refrigerator compressors. Rotors can have different aluminum fill factors according to the fabrication method. In order to examine the association between the fill factor and the efficiency of the rotor, we analyzed the distribution of magnetic flux density using the finite element method (FEM. Next, we made prototype rotors by conventional casting methods and by the proposed casting method and compared their fill factors. In addition, SPIMs were made using the rotors, and their efficiencies were measured using a dynamometer. Moreover, the SPIMs were put to use in a compressor, for testing, and for each SPIM the refrigerating capacity of the compressor was measured with a calorimeter. Based on the results of the FEM analysis of the magnetic flux density and the experiments, the reliability and validity of the proposed method were proven.

  20. 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

    Power regulation of all converter units in a micro-grid should not be only determined by load demand, but also by the available power of each unit, i.e. a converter fed by a battery. Energy management control is essential in order to handle the variety of prime movers which may include different...... 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....... The whole system is explained ahead and finally, Hardware in the loop results obtained with a dSPACE are presented in order to validate the proposed control strategy....

  1. Reliability assessment of single-phase grid-connected PV microinverters considering mission profile and uncertainties

    DEFF Research Database (Denmark)

    Zare, Mohammad Hadi; Mohamadian, Mustafa; Wang, Huai

    2017-01-01

    Microinverters usually connect a PV panel to a Single-phase power grid. In such system, the input power is constant while the output power oscillates twice the line frequency. Thus, the input and output power differences should be stored in a storage component, which is typically an electrolytic...... capacitor. However, electrolytic capacitors are usually blamed for their short lifetime. Recently, some active power decoupling methods are introduced in the literature which can takes advantage of high reliable film capacitors. However, some extra switches and diodes are added to the microinverter which...... can influence the microinverter lifetime. This paper investigates the microinverter reliability according to mission profile where it is installed. To get more accurate results, uncertainties in both lifetime model and manufacturing process are considered. The effect of ambient temperature and solar...

  2. 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...... or film capacitors to store the ripple power, and this again leads to increased component costs. In view of this, this paper presents a symmetrical half-bridge circuit which utilizes the dc-link capacitors to absorb the ripple power, and the only additional components are a pair of switches and a small...... filtering inductor. A design example is presented and the proposed circuit concept is also verified with simulation and experimental results. It shows that at least ten times capacitance reduction can be achieved with the proposed active power decoupling method, which proves its effectiveness....

  3. Pattern formation in single-phase FAC. A stability analysis of an oxide layer

    Energy Technology Data Exchange (ETDEWEB)

    Zinemanas, Daniel [The Israel Electric Corp., Haifa (Israel). Dept. of Chemistry; Herszage, Amiel [The Israel Electric Corp., Haifa (Israel). Dept. of Energy Technologies Development

    2013-03-15

    Pattern formation is a salient characteristic of the flow-accelerated corrosion process, particularly in single-phase flow, where a typical ''orange peel'' surface texture is normally formed. The process of such pattern formation is, however, not well understood. In order to gain some insight into the role of the various processes and parameters involved in this process, a linear stability analysis of an oxide layer based on the Sanchez-Caldera model was performed. According to the results obtained in this study, it follows that the oxide layer is stable regarding perturbations of the oxide thickness or the reaction constant, but it is unstable in respect to perturbations of the mass transfer coefficient. These results suggest therefore that the flow, and not local surface in homogeneities, plays a central role in the pattern formation process. (orig.)

  4. Adaptive fuzzy sliding control of single-phase PV grid-connected inverter.

    Directory of Open Access Journals (Sweden)

    Juntao Fei

    Full Text Available In this paper, an adaptive fuzzy sliding mode controller is proposed to control a two-stage single-phase photovoltaic (PV grid-connected inverter. Two key technologies are discussed in the presented PV system. An incremental conductance method with adaptive step is adopted to track the maximum power point (MPP by controlling the duty cycle of the controllable power switch of the boost DC-DC converter. An adaptive fuzzy sliding mode controller with an integral sliding surface is developed for the grid-connected inverter where a fuzzy system is used to approach the upper bound of the system nonlinearities. The proposed strategy has strong robustness for the sliding mode control can be designed independently and disturbances can be adaptively compensated. Simulation results of a PV grid-connected system verify the effectiveness of the proposed method, demonstrating the satisfactory robustness and performance.

  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...... of the PV source. This results in a constant common-mode voltage and almost zero leakage current. A unipolar Sinusoidal Pulse-Width Modulation (SPWM) technique is used to modulate the inverter to reduce the output current ripple and the filter requirements. The main advantages of this inverter are compact...... clearly verify the performance of the proposed inverter and its practical application for grid-connected PV systems....

  6. Modelling of the modified-LLCL-filter-based single-phase grid-tied Aalborg inverter

    DEFF Research Database (Denmark)

    Liu, Zifa; Wu, Huiyun; Liu, Yuan

    2017-01-01

    Owing to less conduction and switching power losses, the recently proposed Aalborg inverter has high efficiency within a wide range of input DC voltage for single-phase DC/AC power conversion. In theory, the conduction power losses can be further decreased, if an LLCL-filter is adopted instead....... In this study, the small signal analysis for the modified-LLCL-filter-based Aalborg inverter is addressed. Through the modelling, it can be proven that compared with the LCL-filter, the modified-LLCL-filter causes no extra control challenge for the Aalborg inverter, and therefore more inductance in the power...... of an LCL-filter for a voltage source inverter, mainly due to the reduced inductance. The Aalborg inverter shows the characteristic of a current source inverter, when working in the `boost' state. Whether the LLCL-filter can meet the control requirement of this type inverter needs to be further explored...

  7. Solution-phase synthesis of chromium-functionalized single-walled carbon nanotubes

    KAUST Repository

    Kalinina, Irina V.

    2015-03-01

    The solution phase reactions of single-walled carbon nanotubes (SWNTs) with Cr(CO)6 and benzene-Cr(CO)3 can lead to the formation of small chromium clusters. The cluster size can be varied from less than 1 nm to about 4 nm by increasing the reaction time. TEM images suggest that the clusters are deposited predominantly on the exterior walls of the nanotubes. TGA analysis was used to obtain the Cr content and carbon to chromium ratio in the Cr-complexed SWNTs. It is suggested that the carbon nanotube benzenoid structure templates the condensation of chromium atoms and facilitates the loss of carbon monoxide leading to well defined metal clusters.

  8. Compact ASD Topologies for Single-Phase Integrated Motor Drives with Sinusoidal Input Current

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede; Thoegersen, Paul

    2005-01-01

    A standard configuration of an Adjustable Speed Drive (ASD) consists of two separate units: an AC motor, which runs with fixed speed when it is supplied from a constant frequency grid voltage and a frequency converter, which is used to provide the motor with variable voltage-variable frequency......-density integration of the converter caused by the large size of the passive components (electrolytic capacitors and iron chokes) and vibration of the converter enclosure. This paper analyzes the implementation aspects for obtaining a compact and cost effective single-phase ASD with sinusoidal input current...... for high frequency operation, higher core losses will occur, but outside the converter enclosure. The advantages are: the reduction of the number of active semiconductor devices, the reduction of the ASD size and the better integration potential....

  9. A Rotor Flux and Speed Observer for Sensorless Single-Phase Induction Motor Applications

    Directory of Open Access Journals (Sweden)

    Massimo Caruso

    2012-01-01

    Full Text Available It is usual to find single-phase induction motor (SPIM in several house, office, shopping, farm, and industry applications, which are become each time more sophisticated and requiring the development of efficient alternatives to improve the operational performance of this machine. Although the rotor flux and rotational speed are essential variables in order to optimize the operation of a SPIM, the use of conventional sensors to measure them is not a viable option. Thus, the adoption of sensorless strategies is the more reasonable proposal for these cases. This paper presents a rotor flux and rotational speed observer for sensorless applications involving SPIMs. Computer simulations and the experimental results are used to verify the performance of the proposed observer.

  10. Single-phase pressure-drop measurements over low void reactivity fuel

    International Nuclear Information System (INIS)

    Senaratne, U.P.M.; Leung, L.K.H.; Doria, F.J.; Lau, J.H.

    2006-01-01

    An experiment has been performed to obtain pressure-drop measurements over Low Reactivity Fuel (LVRF) bundles in Refrigerant-134a flow. Production LVRF bundles inserted into the test station with either an uncrept or a 5.1% crept flow channel. For comparison purposes, several production Bruce 37-element bundles were also included in the test string. Overall, the single-phase pressure drop of the LVRF bundle is slightly higher than that Bruce 37-element bundle. Pressure-drop measurements were used to derive bundle and loss coefficients for hydraulic calculations in safety analyses. Applying these loss coefficients, an assessment showed that the overall pressure drop over a string of 12 LVRF bundles (after conversion) remains less than that over a string of 13 Bruce 37-element fuel bundles (before conversion) at the Bruce Nuclear Generating Station. (author)

  11. Calculation of single phase AC and monopolar DC hybrid corona effects

    International Nuclear Information System (INIS)

    Zhao, T.; Sebo, S.A.; Kasten, D.G.

    1996-01-01

    Operating a hybrid HVac and HVdc line is an option for increasing the efficiency of power transmission and overcoming the difficulties in obtaining a new right-of-way. This paper proposes a new calculation method for the study of hybrid line corona. The proposed method can be used to calculate dc corona losses and corona currents in dc or ac conductors for single phase ac and monopolar dc hybrid lines. Profiles of electric field strength and ion current density at ground level can be estimated. The effects of the presence of an energized ac conductor on dc conductor corona and dc voltage on ac conductor corona are included in the method. Full-scale and reduced-scale experiments were utilized to investigate the hybrid line corona effects. Verification of the proposed calculation method is given

  12. Comparative study of Nusselt number for a single phase fluid flow using plate heat exchanger

    Directory of Open Access Journals (Sweden)

    Shanmugam Rajasekaran

    2016-01-01

    Full Text Available In this study, the plate heat exchangers are used for various applications in the industries for heat exchange process such as heating, cooling and condensation. The performance of plate heat exchanger depends on many factors such as flow arrangements, plate design, chevron angle, enlargement factor, type of fluid used, etc. The various Nusselt number correlations are developed by considering that the water as a working fluid. The main objective of the present work is to design the experimental set-up for a single phase fluid flow using plate heat exchanger and studied the heat transfer performance. The experiments are carried out for various Reynolds number between 500 and 2200, the heat transfer coefficients are estimated. Based on the experimental results the new correlation is developed for Nusselt number and compared with an existing correlation.

  13. From quantum physics to digital communication: Single sideband continuous phase modulation

    Science.gov (United States)

    Farès, Haïfa; Christian Glattli, D.; Louët, Yves; Palicot, Jacques; Moy, Christophe; Roulleau, Preden

    2018-01-01

    In the present paper, we propose a new frequency-shift keying continuous phase modulation (FSK-CPM) scheme having, by essence, the interesting feature of single-sideband (SSB) spectrum providing a very compact frequency occupation. First, the original principle, inspired from quantum physics (levitons), is presented. Besides, we address the problem of low-complexity coherent detection of this new waveform, based on orthonormal wave functions used to perform matched filtering for efficient demodulation. Consequently, this shows that the proposed modulation can operate using existing digital communication technology, since only well-known operations are performed (e.g., filtering, integration). This SSB property can be exploited to allow large bit rates transmissions at low carrier frequency without caring about image frequency degradation effects typical of ordinary double-sideband signals. xml:lang="fr"

  14. Harmonics Suppression for Single-Phase Grid-Connected Photovoltaic Systems in Different Operation Modes

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2013-01-01

    -connected PV inverters may be severely affected in different operation modes. In this paper, a detailed analysis is conducted to reveal the relationship between the harmonics level with the power factor and the current level in the PV systems. A current control solution which employs an Internal Model...... Principle (IMP) is proposed to suppress the harmonic currents injected into the grid. Experiments are carried out to verify the analysis and the performance of the proposed control method. It is demonstrated that the proposed method presents an effective solution to harmonics suppression for single......-phase grid-connected PV systems in different operation modes. Especially, it can remove higher order harmonics effectively leading to a better power quality compared to the Proportional plus Multi-Resonant Controller, and it has less computational burden....

  15. Femtosecond single electron bunch generation by rotating longitudinal bunch phase space in magnetic field

    International Nuclear Information System (INIS)

    Yang, J.; Kondoh, T.; Kan, K.; Kozawa, T.; Yoshida, Y.; Tagawa, S.

    2006-01-01

    A femtosecond (fs) electron bunching was observed in a photoinjector with a magnetic compressor by rotating the bunch in longitudinal phase space. The bunch length was obtained by measuring Cherenkov radiation of the electron beam with a femtosecond streak camera technique. A single electron bunch with rms bunch length of 98 fs was observed for a 32 MeV electron beam at a charge of 0.17 nC. The relative energy spread and the normalized transverse emittance of the electron beam were 0.2% and 3.8 mm-mrad, respectively. The effect of space charge on the bunch compression was investigated experimentally for charges from 0.17 to 1.25 nC. The dependences of the relative energy spread and the normalized beam transverse emittance on the bunch charge were measured

  16. Simulation of the remanence influence on the transient states in a single-phase multiwinding transformer

    Directory of Open Access Journals (Sweden)

    Wilk Andrzej

    2017-03-01

    Full Text Available This paper presents the mathematical model of a single-phase multi-winding core type transformer taking into account magnetic hysteresis phenomenon based on the feedback Preisach model (FPM. The set of loop differential equations was developed for a K-th winding transformer model where the flux linkages of each winding includes flux Φ common to all windings as a function of magneto motive force Θ of all windings. The first purpose of this paper is to implement a hysteresis nonlinearity involved in the Φ(Θ function which also accounts residual magnetic flux. The second purpose of this paper is experimental validation of the developed transformer model in a capacitor discharge test and several different values of residual magnetic flux.

  17. Adaptive fuzzy sliding control of single-phase PV grid-connected inverter.

    Science.gov (United States)

    Fei, Juntao; Zhu, Yunkai

    2017-01-01

    In this paper, an adaptive fuzzy sliding mode controller is proposed to control a two-stage single-phase photovoltaic (PV) grid-connected inverter. Two key technologies are discussed in the presented PV system. An incremental conductance method with adaptive step is adopted to track the maximum power point (MPP) by controlling the duty cycle of the controllable power switch of the boost DC-DC converter. An adaptive fuzzy sliding mode controller with an integral sliding surface is developed for the grid-connected inverter where a fuzzy system is used to approach the upper bound of the system nonlinearities. The proposed strategy has strong robustness for the sliding mode control can be designed independently and disturbances can be adaptively compensated. Simulation results of a PV grid-connected system verify the effectiveness of the proposed method, demonstrating the satisfactory robustness and performance.

  18. Effects of rolling on single-phase water forced convective heat transfer characteristics

    International Nuclear Information System (INIS)

    Guo Yanming; Gao Puzhen; Huang Zhen

    2010-01-01

    A series of single-phase forced circulation tests in a vertical tube with rolling motion were performed in order to investigate effects of rolling motion on thermal-hydraulic characteristics. The amplitudes of the rolling motion in the tests were 10 degree, 15 degree and 20 degree. The rolling periods were 7.5 s, 10 s, 15 s and 20 s. The Reynolds number was from 6000 to 15000. Heat transfer in the test tube is bated by the rolling motion. As the test-bed rolling more acutely, the heat transfer coefficient of the test tube becomes smaller when the mass flow rate in the test tube is a constant. The heat transfer coefficient calculated by the formula which is for stable state doesn't fit very well with that from experiments. At last a formula for calculating heat transfer in rolling motion was introduced. (authors)

  19. A unified active damping control for single-phase differential buck inverter with LCL-filter

    DEFF Research Database (Denmark)

    Yao, Wenli; Wang, Xiongfei; Zhang, Xiaobin

    2015-01-01

    and control of a grid-connected differential mode buck inverter with an LCL filter. A generalized small-signal model of the inverter is built first with the averaged switching model. It is shown that the LCL filter resonance merely occurs in the differential mode, while an LC filter resonance exists......The single-phase differential mode buck inverter is recently introduced with a differential mode for power transfer and a common mode for actively decoupling the second-order power oscillation. However, it is limited to islanded applications with an LC filter. This paper addresses the stability...... in the common mode, provided that the filter parameters of the two bridges are kept the same. A unified active damping control approach is then proposed for stabilizing the inverter and improving the transient performance under a wide range of grid impedance. Lastly, experimental tests are carried out...

  20. The Use of Mobile, Electrochemical Sensor Nodes for the Measurement of Personal Exposure to Gas-Phase Air Pollutants

    Science.gov (United States)

    Stewart, G.; Popoola, O. A.; Mead, M. I.; McKeating, S. J.; Calleja, M.; Hayes, M.; Baron, R. P.; Saffell, J.; Jones, R.

    2012-12-01

    , and thus also the potential insufficiency at quantifying the risks to health in the surrounding area. Recent campaigns with mobile sensor nodes have included attempts to probe the differences in personal exposure to gas-phase air pollutants at different heights of breathing zone and between different methods of transport.