A Novel Three Phase to Seven Phase Conversion Technique Using Transformer Winding Connections

Directory of Open Access Journals (Sweden)

M. Tabrez

2017-10-01

Full Text Available This paper proposes a novel multiphase transformer connection scheme which converts three phase balanced AC input to seven phase balanced AC output. Generalized theory to convert a three phase utility supply into any number of phases is presented. Based on the proposed generalized principle, a three phase to seven phase power converting transformer design is presented with connection scheme, analysis and simulation and experimental results of the proposed three phase to seven phase conversion transformer. The proposed transformer in this paper is analyzed and compared with the connection scheme for seven phase available in the literature. The connection scheme is found to have higher power density, lower core area and lower core requirement as compared to the available connection scheme of the same rating. Impedance mismatching between different phases of the transformer is observed in the three phase to seven phase transformer available in the literature. As this mismatching introduces error in study of per phase equivalent circuit diagrams as well as imbalance in voltage and currents. The present design also addresses the impedance mismatching issue and reduces mismatching in the proposed transformer design. A prototype of the proposed system is developed and waveforms are presented. The proposed design is verified using simulation and validated using experimental approach.

Unconventional magnetic phase separation in γ -CoV2O6

Science.gov (United States)

Shen, L.; Jellyman, E.; Forgan, E. M.; Blackburn, E.; Laver, M.; Canévet, E.; Schefer, J.; He, Z.; Itoh, M.

2017-08-01

We have explored the magnetism in the nongeometrically frustrated spin-chain system γ -CoV2O6 which possesses a complex magnetic exchange network. Our neutron diffraction patterns at low temperatures (T ≤TN=6.6 K) are best described by a model in which two magnetic phases coexist in a volume ratio 65(1) : 35(1), with each phase consisting of a single spin modulation. This model fits previous studies and our observations better than the model proposed by Lenertz et al. [J. Phys. Chem. C 118, 13981 (2014), 10.1021/jp503389c], which consisted of one phase with two spin modulations. By decreasing the temperature from TN, the minority phase of our model undergoes an incommensurate-commensurate lock-in transition at T*=5.6 K. Based on these results, we propose that phase separation is an alternative approach for degeneracy-lifting in frustrated magnets.

Predictive Duty Cycle Control of Three-Phase Active-Front-End Rectifiers

DEFF Research Database (Denmark)

Song, Zhanfeng; Tian, Yanjun; Chen, Wei

2016-01-01

This paper proposed an on-line optimizing duty cycle control approach for three-phase active-front-end rectifiers, aiming to obtain the optimal control actions under different operating conditions. Similar to finite control set model predictive control strategy, a cost function previously...

On Low-Pass Phase Noise Mitigation in OFDM System for mmWave Communications

DEFF Research Database (Denmark)

Chen, Xiaoming; Fan, Wei; Zhang, Anxue

2017-01-01

A phase noise (PN) mitigation scheme was proposed for orthogonal frequency division multiplexing (OFDM) in a previous work. The proposed scheme does not require detailed knowledge of PN statistics and can eectively compensate the PN with sucient number of unknowns. In this paper, we analyze....... It is also shown that the PN spectral shape of the phase-lockedloop (PLL) based oscillator also aects the PN mitigation and that a larger PN may not necessarily degrade the performance of the OFDM system with PN mitigation. Simulations with realistic millimeter-wave (mmWave) PN and channel models...

7 CFR 3403.9 - Submission of proposals.

Science.gov (United States)

2010-01-01

... Submission and Evaluation of Proposals § 3403.9 Submission of proposals. The SBIR program solicitation for Phase I proposals and the correspondence requesting Phase II proposals will provide the deadline date... 7 Agriculture 15 2010-01-01 2010-01-01 false Submission of proposals. 3403.9 Section 3403.9...

7 CFR 3403.6 - Content of proposals.

Science.gov (United States)

2010-01-01

... SBIR Phase I or Phase II effort. Proposals principally for the development of proven concepts toward... 7 Agriculture 15 2010-01-01 2010-01-01 false Content of proposals. 3403.6 Section 3403.6... Preparation of Proposals § 3403.6 Content of proposals. (a) The proposed research must be responsive to one of...

Stochastic modelling of two-phase flows including phase change

International Nuclear Information System (INIS)

Hurisse, O.; Minier, J.P.

2011-01-01

Stochastic modelling has already been developed and applied for single-phase flows and incompressible two-phase flows. In this article, we propose an extension of this modelling approach to two-phase flows including phase change (e.g. for steam-water flows). Two aspects are emphasised: a stochastic model accounting for phase transition and a modelling constraint which arises from volume conservation. To illustrate the whole approach, some remarks are eventually proposed for two-fluid models. (authors)

interThermalPhaseChangeFoam—A framework for two-phase flow simulations with thermally driven phase change

Directory of Open Access Journals (Sweden)

Mahdi Nabil

2016-01-01

Full Text Available The volume-of-fluid (VOF approach is a mature technique for simulating two-phase flows. However, VOF simulation of phase-change heat transfer is still in its infancy. Multiple closure formulations have been proposed in the literature, each suited to different applications. While these have enabled significant research advances, few implementations are publicly available, actively maintained, or inter-operable. Here, a VOF solver is presented (interThermalPhaseChangeFoam, which incorporates an extensible framework for phase-change heat transfer modeling, enabling simulation of diverse phenomena in a single environment. The solver employs object oriented OpenFOAM library features, including Run-Time-Type-Identification to enable rapid implementation and run-time selection of phase change and surface tension force models. The solver is packaged with multiple phase change and surface tension closure models, adapted and refined from earlier studies. This code has previously been applied to study wavy film condensation, Taylor flow evaporation, nucleate boiling, and dropwise condensation. Tutorial cases are provided for simulation of horizontal film condensation, smooth and wavy falling film condensation, nucleate boiling, and bubble condensation. Validation and grid sensitivity studies, interfacial transport models, effects of spurious currents from surface tension models, effects of artificial heat transfer due to numerical factors, and parallel scaling performance are described in detail in the Supplemental Material (see Appendix A. By incorporating the framework and demonstration cases into a single environment, users can rapidly apply the solver to study phase-change processes of interest.

interThermalPhaseChangeFoam-A framework for two-phase flow simulations with thermally driven phase change

Science.gov (United States)

Nabil, Mahdi; Rattner, Alexander S.

The volume-of-fluid (VOF) approach is a mature technique for simulating two-phase flows. However, VOF simulation of phase-change heat transfer is still in its infancy. Multiple closure formulations have been proposed in the literature, each suited to different applications. While these have enabled significant research advances, few implementations are publicly available, actively maintained, or inter-operable. Here, a VOF solver is presented (interThermalPhaseChangeFoam), which incorporates an extensible framework for phase-change heat transfer modeling, enabling simulation of diverse phenomena in a single environment. The solver employs object oriented OpenFOAM library features, including Run-Time-Type-Identification to enable rapid implementation and run-time selection of phase change and surface tension force models. The solver is packaged with multiple phase change and surface tension closure models, adapted and refined from earlier studies. This code has previously been applied to study wavy film condensation, Taylor flow evaporation, nucleate boiling, and dropwise condensation. Tutorial cases are provided for simulation of horizontal film condensation, smooth and wavy falling film condensation, nucleate boiling, and bubble condensation. Validation and grid sensitivity studies, interfacial transport models, effects of spurious currents from surface tension models, effects of artificial heat transfer due to numerical factors, and parallel scaling performance are described in detail in the Supplemental Material (see Appendix A). By incorporating the framework and demonstration cases into a single environment, users can rapidly apply the solver to study phase-change processes of interest.

Phase-flip bifurcation in a coupled Josephson junction neuron system

Energy Technology Data Exchange (ETDEWEB)

Segall, Kenneth, E-mail: ksegall@colgate.edu [Department of Physics and Astronomy, Colgate University, Hamilton, NY 13346 (United States); Guo, Siyang; Crotty, Patrick [Department of Physics and Astronomy, Colgate University, Hamilton, NY 13346 (United States); Schult, Dan [Department of Mathematics, Colgate University, Hamilton, NY 13346 (United States); Miller, Max [Department of Physics and Astronomy, Colgate University, Hamilton, NY 13346 (United States)

2014-12-15

Aiming to understand group behaviors and dynamics of neural networks, we have previously proposed the Josephson junction neuron (JJ neuron) as a fast analog model that mimics a biological neuron using superconducting Josephson junctions. In this study, we further analyze the dynamics of the JJ neuron numerically by coupling one JJ neuron to another. In this coupled system we observe a phase-flip bifurcation, where the neurons synchronize out-of-phase at weak coupling and in-phase at strong coupling. We verify this by simulation of the circuit equations and construct a bifurcation diagram for varying coupling strength using the phase response curve and spike phase difference map. The phase-flip bifurcation could be observed experimentally using standard digital superconducting circuitry.

Phase-flip bifurcation in a coupled Josephson junction neuron system

International Nuclear Information System (INIS)

Segall, Kenneth; Guo, Siyang; Crotty, Patrick; Schult, Dan; Miller, Max

2014-01-01

Aiming to understand group behaviors and dynamics of neural networks, we have previously proposed the Josephson junction neuron (JJ neuron) as a fast analog model that mimics a biological neuron using superconducting Josephson junctions. In this study, we further analyze the dynamics of the JJ neuron numerically by coupling one JJ neuron to another. In this coupled system we observe a phase-flip bifurcation, where the neurons synchronize out-of-phase at weak coupling and in-phase at strong coupling. We verify this by simulation of the circuit equations and construct a bifurcation diagram for varying coupling strength using the phase response curve and spike phase difference map. The phase-flip bifurcation could be observed experimentally using standard digital superconducting circuitry

Calculation of proton-deuteron phase parameters including the Coulomb force

International Nuclear Information System (INIS)

Alt, E.O.; Sandhas, W.; Ziegelmann, H.

1985-04-01

A previously proposed exact method for including the Coulomb force in three-body collisions is applied to proton-deuteron scattering. We present phase shifts for angular momenta up to L=9, from elastic threshold to 50 MeV proton laboratory energy. Separable rank-one potentials are taken for the nuclear interactions. A charge-independent and a charge-symmetric choise, while leading to different neutron-deuteron and proton-deuteron phase parameters, nevertheless yields practically the same Coulomb corrections. We, moreover, investigate the question of P-wave resonances.A critical comparison of our results with those obtained in a co-ordinate space formalism is performed. Furthermore, proposals for an approximate inclusion of the Coulomb potential are tested, and found unsatisfactory. (orig.)

Improving the phase stability of the SLAC rf driveline network for SLC operation

International Nuclear Information System (INIS)

Weaver, J.N.; Hogg, H.A.

1983-01-01

Successful operation of the Stanford Linear Collider (SLC) will require greater phase stability from the two-mile long rf drive network than previous linac operation did. This paper discusses four proposed modifications of the present system that should help achieve the general objective to reduce all long term temperature and atmospheric pressure induced phase variations to less than 20 0 at 2856 MHz, so that the phase/amplitude detector subsystems, which will control the network output phases relative to a beam reference, will operate within their most accurate ranges

Phase pupil functions for focal-depth enhancement derived from a Wigner distribution function.

Science.gov (United States)

Zalvidea, D; Sicre, E E

1998-06-10

A method for obtaining phase-retardation functions, which give rise to an increase of the image focal depth, is proposed. To this end, the Wigner distribution function corresponding to a specific aperture that has an associated small depth of focus in image space is conveniently sheared in the phase-space domain to generate a new Wigner distribution function. From this new function a more uniform on-axis image irradiance can be accomplished. This approach is illustrated by comparison of the imaging performance of both the derived phase function and a previously reported logarithmic phase distribution.

Technical Proposal for the Phase-II Upgrade of the CMS Detector

CERN Document Server

CMS Collaboration; Contardo, D; Klute, M; Mans, J; Silvestris, L; Butler, J; CERN. Geneva. The LHC experiments Committee; LHCC

2015-01-01

This Technical Proposal presents the upgrades foreseen to prepare the CMS experiment for the High Luminosity LHC. In this second phase of the LHC physics program, the accelerator will provide to CMS an additional integrated luminosity of about 2500 fb-1 over 10 years of operation, starting in 2025. This will substantially enlarge the mass reach in the search for new particles and will also greatly extend the potential to study the properties of the Higgs boson discovered at the LHC in 2012. In order to meet the experimental challenges of unprecedented p-p luminosity, the CMS collaboration will need to address the aging of the present detector and to improve the ability of the apparatus to isolate and precisely measure the products of the most interesting collisions. This document describes the conceptual designs and the expected performance of the upgrades, along with the plans to develop the appropriate experimental techniques. The infrastructure upgrades and the logistics of the installation in the experim...

Improving the efficiency of molecular replacement by utilizing a new iterative transform phasing algorithm

Energy Technology Data Exchange (ETDEWEB)

He, Hongxing; Fang, Hengrui [Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, Texas 77204 (United States); Miller, Mitchell D. [Department of BioSciences, Rice University, Houston, Texas 77005 (United States); Phillips, George N. Jr [Department of BioSciences, Rice University, Houston, Texas 77005 (United States); Department of Chemistry, Rice University, Houston, Texas 77005 (United States); Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Su, Wu-Pei, E-mail: wpsu@uh.edu [Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, Texas 77204 (United States)

2016-07-15

An iterative transform algorithm is proposed to improve the conventional molecular-replacement method for solving the phase problem in X-ray crystallography. Several examples of successful trial calculations carried out with real diffraction data are presented. An iterative transform method proposed previously for direct phasing of high-solvent-content protein crystals is employed for enhancing the molecular-replacement (MR) algorithm in protein crystallography. Target structures that are resistant to conventional MR due to insufficient similarity between the template and target structures might be tractable with this modified phasing method. Trial calculations involving three different structures are described to test and illustrate the methodology. The relationship of the approach to PHENIX Phaser-MR and MR-Rosetta is discussed.

QPSK Modulator with Continuous Phase and Fast Response Based on Phase-Locked Loop

Directory of Open Access Journals (Sweden)

L. Kirasamuthranon

2017-06-01

Full Text Available Among M-phase shift keying (M-PSK schemes, quadrature phase-shift keying (QPSK is used most often because of its efficient bandwidth consumption. However, in comparison with minimum-shift keying, which has continuous phase transitions, QPSK requires a higher bandwidth to transmit a signal. This article focuses on the phase transitions in QPSK signals, and a QPSK modulator based on a phase-locked loop (PLL is proposed. The PLL circuit in the proposed system differs from that of conventional PLL circuits because a three-input XOR gate and a summing circuit are used. With these additional components, the proposed PLL provides a continuous phase change in the QPSK signal. Consequently, the required bandwidth for transmitting the QPSK signal when using the proposed circuit is less than that for a conventional QPSK signal with a discontinuous phase. The analytical results for the proposed system in the time domain agree well with the experimental and simulation results of the circuit. Both the theoretical and experimental results thus confirm that the proposed technique can be realized in real-world applications.

Low-activity waste envelope definitions for the TWRS Privatization Phase I Request For Proposal

International Nuclear Information System (INIS)

Patello, G.K.; Lauerhass, L.; Myers, R.L.; Wiemers, K.D.

1996-11-01

Radioactive waste has been stored in large underground storage tanks at the Hanford Site since 1944. Approximately 212 million liters of waste containing approximately 240,000 metric tons of processed chemicals and 177 mega-curies of radionuclides are now stored in 177 tanks. These caustic wastes are in the form of liquids, slurries, saltcakes, and sludge. In 1991, the Tank Waste Remediation System (TWRS) Program was established to manage, retrieve, treat, immobilize, and dispose of these wastes in a safe, environmentally sound, and cost-effective manner. The Department of Energy (DOE) has believes that it is feasible to privatize portions of the TWRS Program. Under the privatization strategy embodied in the Request for Proposal (RFP), DOE will purchase services from a contractor-owned, contractor-operated facility under a fixed-price contract. Phase I of the TWRS privatization strategy is a proof-of-concept/commercial demonstration-scale effort. The objectives of Phase I are to demonstrate the technical and business viability of using privatized facilities to treat Hanford tank waste; define and maintain required levels of radiological, nuclear, process, and occupational safety; maintain environmental protection and compliance; and substantially reduce life-cycle costs and time required to treat Hanford tank waste. Three low-activity waste (LAW) envelopes are identified for Phase I of the privatization contract and are representative of the range of Hanford double-shelled tank (DST) waste

Low-activity waste envelope definitions for the TWRS Privatization Phase I Request For Proposal

Energy Technology Data Exchange (ETDEWEB)

Patello, G.K.; Lauerhass, L.; Myers, R.L.; Wiemers, K.D.

1996-11-01

Radioactive waste has been stored in large underground storage tanks at the Hanford Site since 1944. Approximately 212 million liters of waste containing approximately 240,000 metric tons of processed chemicals and 177 mega-curies of radionuclides are now stored in 177 tanks. These caustic wastes are in the form of liquids, slurries, saltcakes, and sludge. In 1991, the Tank Waste Remediation System (TWRS) Program was established to manage, retrieve, treat, immobilize, and dispose of these wastes in a safe, environmentally sound, and cost-effective manner. The Department of Energy (DOE) has believes that it is feasible to privatize portions of the TWRS Program. Under the privatization strategy embodied in the Request for Proposal (RFP), DOE will purchase services from a contractor-owned, contractor-operated facility under a fixed-price contract. Phase I of the TWRS privatization strategy is a proof-of-concept/commercial demonstration-scale effort. The objectives of Phase I are to demonstrate the technical and business viability of using privatized facilities to treat Hanford tank waste; define and maintain required levels of radiological, nuclear, process, and occupational safety; maintain environmental protection and compliance; and substantially reduce life-cycle costs and time required to treat Hanford tank waste. Three low-activity waste (LAW) envelopes are identified for Phase I of the privatization contract and are representative of the range of Hanford double-shelled tank (DST) waste.

Frequency domain phase retrieval of simultaneous multi-wavelength phase-shifting interferometry

International Nuclear Information System (INIS)

Yin, Zhenxing; Zhong, Liyun; Xu, Xiaofei; Zhang, Wangping; Lu, Xiaoxu; Tian, Jindong

2016-01-01

In simultaneous multi-wavelength phase-shifting interferometry, we propose a novel frequency domain phase retrieval (FDPR) algorithm. First, using only a one-time phase-shifting operation, a sequence of simultaneous multi-wavelength phase-shifting interferograms (SPSMWIs) are captured by a monochrome charge-coupled device. Second, by performing a Fourier transform for each pixel of SPSMWIs, the wrapped phases of each wavelength can be retrieved from the complex amplitude located in the spectral peak of each wavelength. Finally, the phase of the synthetic wavelength can be obtained by the subtraction between the wrapped phases of a single wavelength. In this study, the principle and the application condition of the proposed approach are discussed. Both the simulation and the experimental result demonstrate the simple and convenient performance of the proposed FDPR approach. (paper)

Project NOAH: Regulating modern sea-level rise. Phase II: Jerusalem Underground

Science.gov (United States)

Newman, Walter S.; Fairbridge, Rhodes W.

This proposal builds a high-speed inter-urban express between Jerusalem and Tel Aviv, generates 1500 megawatts of hydroelectric energy, curtails littoral erosion, builds a port along the Israeli Mediterranean coast and demands peaceful cooperation on both sides of the Jordan River. Phase II represents a pilot project demonstrating the feasibility of continuing to regulate world sea-level by a new series of water regulation schemes. Phase I previously described all those projects already completed or underway which have inadvertently and/or unintentionally served the purpose of sea-level regulation. These forms of Phase I sea-level regulation include large and small reservoirs, irrigation projects, water infiltration schemes, farm ponds, and swimming and reflecting pools. All these water storage projects have already exercised a very appreciable brake on 20th century sea-level rise. Phase II outlines a high-visibility proposal which will serve to illustrate the viability of “Project NOAH”.

The next phase in professional services research: From implementation to sustainability.

Science.gov (United States)

Crespo-Gonzalez, Carmen; Garcia-Cardenas, Victoria; Benrimoj, Shalom I

The provision of professional pharmacy services has been heralded as the professional and the economic future of pharmacy. There are different phases involved in a service creation including service design, impact evaluation, implementation and sustainability. The two first phases have been subject to extensive research. In the last years the principles of Implementation science have been applied in pharmacy to study the initial uptake and integration of evidence-based services into routine practice. However, little attention has been paid to the sustainability of those services, during which there is a continued use of the service previously implemented to achieve and sustain long-term outcomes. The objective of this commentary is to describe the differences and common characteristics between the implementation and the sustainability phase and to propose a definition for pharmacy. A literature search was performed. Four critical elements were identified: 1. The aim of the implementation phase is to incorporate new services into practice, the sustainability phase's aim is to make the services routine to achieve and sustain long-term benefits 2. At the implementation phase planned activities are used as a process to integrate the new service, at the sustainability phase there is a continuous improvement of the service 3. The implementation phase occurs during the period of time between the adoption of a service and its integration. Some authors suggest the sustainability phase is a concomitant phase with the implementation phase and others suggest it is independent 4. There is a lack of consensus regarding the duration of each phase. The following definition of sustainability for pharmacy services is proposed: "Sustainability is a phase in the process of a professional pharmacy service, in which the service previously integrated into practice during the implementation phase is routinized and institutionalized over time to achieve and sustain the expected service

X-cube model on generic lattices: Fracton phases and geometric order

Science.gov (United States)

Slagle, Kevin; Kim, Yong Baek

2018-04-01

Fracton order is a new kind of quantum order characterized by topological excitations that exhibit remarkable mobility restrictions and a robust ground-state degeneracy (GSD) which can increase exponentially with system size. In this paper, we present a generic lattice construction (in three dimensions) for a generalized X-cube model of fracton order, where the mobility restrictions of the subdimensional particles inherit the geometry of the lattice. This helps explain a previous result that lattice curvature can produce a robust GSD, even on a manifold with trivial topology. We provide explicit examples to show that the (zero-temperature) phase of matter is sensitive to the lattice geometry. In one example, the lattice geometry confines the dimension-1 particles to small loops, which allows the fractons to be fully mobile charges, and the resulting phase is equivalent to (3+1)-dimensional toric code. However, the phase is sensitive to more than just lattice curvature; different lattices without curvature (e.g., cubic or stacked kagome lattices) also result in different phases of matter, which are separated by phase transitions. Unintuitively, however, according to a previous definition of phase [X. Chen et al., Phys. Rev. B 82, 155138 (2010), 10.1103/PhysRevB.82.155138], even just a rotated or rescaled cubic results in different phases of matter, which motivates us to propose a coarser definition of phase for gapped ground states and fracton order. This equivalence relation between ground states is given by the composition of a local unitary transformation and a quasi-isometry (which can rotate and rescale the lattice); equivalently, ground states are in the same phase if they can be adiabatically connected by varying both the Hamiltonian and the positions of the degrees of freedom (via a quasi-isometry). In light of the importance of geometry, we further propose that fracton orders should be regarded as a geometric order.

Gefitinib plus cisplatin and radiotherapy in previously untreated head and neck squamous cell carcinoma: A phase II, randomized, double-blind, placebo-controlled study

International Nuclear Information System (INIS)

Gregoire, Vincent; Hamoir, Marc; Chen Changhu; Kane, Madeleine; Kawecki, Andrzej; Julka, Pramod K.; Wang, Hung-Ming; Prasad, Srihari; D'Cruz, Anil K.; Radosevic-Jelic, Ljiljana; Kumar, Rejnish R.; Korzeniowski, Stanislaw; Fijuth, Jacek; Machiels, Jean-Pascal; Sellers, Mark V.; Tchakov, Ilian; Raben, David

2011-01-01

Background and purpose: To assess the efficacy and safety of gefitinib given concomitantly and/or as maintenance therapy to standard cisplatin/radiotherapy for previously untreated, unresected, stage III/IV non-metastatic SCCHN. Materials and methods: In this phase II, double-blind, study, 226 patients were randomized to gefitinib 250 mg/day, 500 mg/day or placebo in two phases: a concomitant phase (gefitinib or placebo with chemoradiotherapy), followed by a maintenance phase (gefitinib or placebo alone). Primary endpoint was local disease control rate (LDCR) at 2 years; secondary endpoints were LDCR at 1 year, objective response rate, progression-free survival, overall survival, and safety and tolerability. Results: Gefitinib (250 and 500 mg/day) did not improve 2-year LDCR compared with placebo either when given concomitantly with chemoradiotherapy (32.7% vs. 33.6%, respectively; OR 0.921, 95% CI 0.508, 1.670 [1-sided p = 0.607]) or as maintenance therapy (28.8% vs. 37.4%, respectively; OR 0.684, 95% CI 0.377, 1.241 [1-sided p = 0.894]). Secondary efficacy outcomes were broadly consistent with the 2-year LDCR results. In both doses, gefitinib was well-tolerated and did not adversely affect the safety and tolerability of concomitant chemoradiotherapy. Conclusion: Gefitinib was well-tolerated, but did not improve efficacy compared with placebo when given concomitantly with chemoradiotherapy, or as maintenance therapy alone.

77 FR 32069 - Airworthiness Directives; Gulfstream Aerospace LP (Type Certificate Previously Held by Israel...

Science.gov (United States)

2012-05-31

... Aerospace LP (Type Certificate Previously Held by Israel Aircraft Industries, Ltd.) Airplanes AGENCY... previously held by Israel Aircraft Industries, Ltd.) Model Galaxy and Gulfstream 200 airplanes. This proposed... receive about this proposed AD. Discussion The Civil Aviation Authority of Israel (CAAI), which is the...

A previous hamstring injury affects kicking mechanics in soccer players.

Science.gov (United States)

Navandar, Archit; Veiga, Santiago; Torres, Gonzalo; Chorro, David; Navarro, Enrique

2018-01-10

Although the kicking skill is influenced by limb dominance and sex, how a previous hamstring injury affects kicking has not been studied in detail. Thus, the objective of this study was to evaluate the effect of sex and limb dominance on kicking in limbs with and without a previous hamstring injury. 45 professional players (males: n=19, previously injured players=4, age=21.16 ± 2.00 years; females: n=19, previously injured players=10, age=22.15 ± 4.50 years) performed 5 kicks each with their preferred and non-preferred limb at a target 7m away, which were recorded with a three-dimensional motion capture system. Kinematic and kinetic variables were extracted for the backswing, leg cocking, leg acceleration and follow through phases. A shorter backswing (20.20 ± 3.49% vs 25.64 ± 4.57%), and differences in knee flexion angle (58 ± 10o vs 72 ± 14o) and hip flexion velocity (8 ± 0rad/s vs 10 ± 2rad/s) were observed in previously injured, non-preferred limb kicks for females. A lower peak hip linear velocity (3.50 ± 0.84m/s vs 4.10 ± 0.45m/s) was observed in previously injured, preferred limb kicks of females. These differences occurred in the backswing and leg-cocking phases where the hamstring muscles were the most active. A variation in the functioning of the hamstring muscles and that of the gluteus maximus and iliopsoas in the case of a previous injury could account for the differences observed in the kicking pattern. Therefore, the effects of a previous hamstring injury must be considered while designing rehabilitation programs to re-educate kicking movement.

Proposal for a phase-coherent thermoelectric transistor

International Nuclear Information System (INIS)

Giazotto, F.; Robinson, J. W. A.; Moodera, J. S.; Bergeret, F. S.

2014-01-01

Identifying materials and devices which offer efficient thermoelectric effects at low temperature is a major obstacle for the development of thermal management strategies for low-temperature electronic systems. Superconductors cannot offer a solution since their near perfect electron-hole symmetry leads to a negligible thermoelectric response; however, here we demonstrate theoretically a superconducting thermoelectric transistor which offers unparalleled figures of merit of up to ∼45 and Seebeck coefficients as large as a few mV/K at sub-Kelvin temperatures. The device is also phase-tunable meaning its thermoelectric response for power generation can be precisely controlled with a small magnetic field. Our concept is based on a superconductor-normal metal-superconductor interferometer in which the normal metal weak-link is tunnel coupled to a ferromagnetic insulator and a Zeeman split superconductor. Upon application of an external magnetic flux, the interferometer enables phase-coherent manipulation of thermoelectric properties whilst offering efficiencies which approach the Carnot limit

Proposal for a phase-coherent thermoelectric transistor

Energy Technology Data Exchange (ETDEWEB)

Giazotto, F., E-mail: giazotto@sns.it [NEST, Instituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa (Italy); Robinson, J. W. A., E-mail: jjr33@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Moodera, J. S. [Department of Physics and Francis Bitter Magnet Lab, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Bergeret, F. S., E-mail: sebastian-bergeret@ehu.es [Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, Manuel de Lardizabal 4, E-20018 San Sebastián (Spain); Donostia International Physics Center (DIPC), Manuel de Lardizabal 5, E-20018 San Sebastián (Spain)

2014-08-11

Identifying materials and devices which offer efficient thermoelectric effects at low temperature is a major obstacle for the development of thermal management strategies for low-temperature electronic systems. Superconductors cannot offer a solution since their near perfect electron-hole symmetry leads to a negligible thermoelectric response; however, here we demonstrate theoretically a superconducting thermoelectric transistor which offers unparalleled figures of merit of up to ∼45 and Seebeck coefficients as large as a few mV/K at sub-Kelvin temperatures. The device is also phase-tunable meaning its thermoelectric response for power generation can be precisely controlled with a small magnetic field. Our concept is based on a superconductor-normal metal-superconductor interferometer in which the normal metal weak-link is tunnel coupled to a ferromagnetic insulator and a Zeeman split superconductor. Upon application of an external magnetic flux, the interferometer enables phase-coherent manipulation of thermoelectric properties whilst offering efficiencies which approach the Carnot limit.

Gravitational radiation from first-order phase transitions

International Nuclear Information System (INIS)

Child, Hillary L.; Giblin, John T. Jr.

2012-01-01

It is believed that first-order phase transitions at or around the GUT scale will produce high-frequency gravitational radiation. This radiation is a consequence of the collisions and coalescence of multiple bubbles during the transition. We employ high-resolution lattice simulations to numerically evolve a system of bubbles using only scalar fields, track the anisotropic stress during the process and evolve the metric perturbations associated with gravitational radiation. Although the radiation produced during the bubble collisions has previously been estimated, we find that the coalescence phase enhances this radiation even in the absence of a coupled fluid or turbulence. We comment on how these simulations scale and propose that the same enhancement should be found at the Electroweak scale; this modification should make direct detection of a first-order electroweak phase transition easier

Gravitational radiation from first-order phase transitions

Energy Technology Data Exchange (ETDEWEB)

Child, Hillary L.; Giblin, John T. Jr., E-mail: childh@kenyon.edu, E-mail: giblinj@kenyon.edu [Department of Physics, Kenyon College, 201 North College Road, Gambier, OH 43022 (United States)

2012-10-01

It is believed that first-order phase transitions at or around the GUT scale will produce high-frequency gravitational radiation. This radiation is a consequence of the collisions and coalescence of multiple bubbles during the transition. We employ high-resolution lattice simulations to numerically evolve a system of bubbles using only scalar fields, track the anisotropic stress during the process and evolve the metric perturbations associated with gravitational radiation. Although the radiation produced during the bubble collisions has previously been estimated, we find that the coalescence phase enhances this radiation even in the absence of a coupled fluid or turbulence. We comment on how these simulations scale and propose that the same enhancement should be found at the Electroweak scale; this modification should make direct detection of a first-order electroweak phase transition easier.

Simulation of the catalyst layer in PEMFC based on a novel two-phase lattice model

Energy Technology Data Exchange (ETDEWEB)

Zhang Jiejing; Yang Wei; Xu Li [School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, Tianjin University, Tianjin 300072 (China); Wang Yuxin, E-mail: yxwang@tju.edu.cn [School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, Tianjin University, Tianjin 300072 (China)

2011-08-01

Highlights: > We propose a novel two phase lattice model of catalyst layer in PEMFC. > The model features a catalyst phase and a mixed ionomer and pores phase. > Transport and electrochemical reaction in the lattice are simulated. > The model enables more accurate results than pore-solid two phase model. > Profiles of oxygen level and reaction rate across catalyst layer vary with cell current. - Abstract: A lattice model of catalyst layer in proton exchange membrane fuel cells (PEMFCs), consisting of randomly distributed catalyst phase (C phase) and mixed ionomer-pore phase (IP phase), was established by means of Monte Carlo method. Transport and electrochemical reactions in the model catalyst layer were calculated. The newly proposed C-IP model was compared with previously established pore-solid two phase model. The variation of oxygen level and reaction rate along the thickness of catalyst layer with cell current was discussed. The effect of ionomer distribution across catalyst layer was studied by comparing profiles of oxygen level, reaction rate and overpotential, as well as corresponding polarization curves.

Grating-based x-ray differential phase contrast imaging with twin peaks in phase-stepping curves—phase retrieval and dewrapping

Energy Technology Data Exchange (ETDEWEB)

Yang, Yi; Xie, Huiqiao; Tang, Xiangyang, E-mail: xiangyang.tang@emory.edu [Imaging and Medical Physics, Department of Radiology and Imaging Sciences, Emory University School of Medicine, 1701 Uppergate Dr., C-5018, Atlanta, Georgia 30322 (United States); Cai, Weixing [Department of Radiation Oncology, Brigham and Women’s Hospital Harvard Medical School, 75 Francis Street, Boston, Massachusetts 02115 (United States); Mao, Hui [Laboratory of Functional and Molecular Imaging and Nanomedicine, Department of Radiology and Imaging Sciences, Emory University School of Medicine, 1841 Clifton Road NE, Atlanta, Georgia 30329 (United States)

2016-06-15

Purpose: X-ray differential phase contrast CT implemented with Talbot interferometry employs phase-stepping to extract information of x-ray attenuation, phase shift, and small-angle scattering. Since inaccuracy may exist in the absorption grating G{sub 2} due to an imperfect fabrication, the effective period of G{sub 2} can be as large as twice the nominal period, leading to a phenomenon of twin peaks that differ remarkably in their heights. In this work, the authors investigate how to retrieve and dewrap the phase signal from the phase-stepping curve (PSC) with the feature of twin peaks for x-ray phase contrast imaging. Methods: Based on the paraxial Fresnel–Kirchhoff theory, the analytical formulae to characterize the phenomenon of twin peaks in the PSC are derived. Then an approach to dewrap the retrieved phase signal by jointly using the phases of the first- and second-order Fourier components is proposed. Through an experimental investigation using a prototype x-ray phase contrast imaging system implemented with Talbot interferometry, the authors evaluate and verify the derived analytic formulae and the proposed approach for phase retrieval and dewrapping. Results: According to theoretical analysis, the twin-peak phenomenon in PSC is a consequence of combined effects, including the inaccuracy in absorption grating G{sub 2}, mismatch between phase grating and x-ray source spectrum, and finite size of x-ray tube’s focal spot. The proposed approach is experimentally evaluated by scanning a phantom consisting of organic materials and a lab mouse. The preliminary data show that compared to scanning G{sub 2} over only one single nominal period and correcting the measured phase signal with an intuitive phase dewrapping method that is being used in the field, stepping G{sub 2} over twice its nominal period and dewrapping the measured phase signal with the proposed approach can significantly improve the quality of x-ray differential phase contrast imaging in both

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.

Implant breast reconstruction after salvage mastectomy in previously irradiated patients.

Science.gov (United States)

Persichetti, Paolo; Cagli, Barbara; Simone, Pierfranco; Cogliandro, Annalisa; Fortunato, Lucio; Altomare, Vittorio; Trodella, Lucio

2009-04-01

The most common surgical approach in case of local tumor recurrence after quadrantectomy and radiotherapy is salvage mastectomy. Breast reconstruction is the subsequent phase of the treatment and the plastic surgeon has to operate on previously irradiated and manipulated tissues. The medical literature highlights that breast reconstruction with tissue expanders is not a pursuable option, considering previous radiotherapy a contraindication. The purpose of this retrospective study is to evaluate the influence of previous radiotherapy on 2-stage breast reconstruction (tissue expander/implant). Only patients with analogous timing of radiation therapy and the same demolitive and reconstructive procedures were recruited. The results of this study prove that, after salvage mastectomy in previously irradiated patients, implant reconstruction is still possible. Further comparative studies are, of course, advisable to draw any conclusion on the possibility to perform implant reconstruction in previously irradiated patients.

The Proposed Heating and Cooling System in the CH2 Building and Its Impact on Occupant Productivity

Directory of Open Access Journals (Sweden)

Lu Aye

2012-11-01

Full Text Available Melbourne's climatic conditions demand that its buildings require both heating and cooling systems. In a multi-storey office building , however, cooling requirements will dominate. How the internal space is cooled and ventilation air is delivered will significantly impact on occupant comfort. This paper discusses the heating and cooling systems proposed for the CH2building. The paper critiques the proposed systems against previous experience, both internationally and in Australia. While the heating system employs proven technologies, less established techniques are proposed for the cooling system. Air movement in the shower towers, for example, is to be naturally induced and this has not always been successful elsewhere. Phase change material for storage of "coolth" does not appear to have been demonstrated previously in a commercial building, so the effectiveness of the proposed system is uncertain. A conventional absorption chiller backs up the untried elements of the cooling system, so that ultimately occupant comfort should not be compromised .

Phase unwrapping algorithm using polynomial phase approximation and linear Kalman filter.

Science.gov (United States)

Kulkarni, Rishikesh; Rastogi, Pramod

2018-02-01

A noise-robust phase unwrapping algorithm is proposed based on state space analysis and polynomial phase approximation using wrapped phase measurement. The true phase is approximated as a two-dimensional first order polynomial function within a small sized window around each pixel. The estimates of polynomial coefficients provide the measurement of phase and local fringe frequencies. A state space representation of spatial phase evolution and the wrapped phase measurement is considered with the state vector consisting of polynomial coefficients as its elements. Instead of using the traditional nonlinear Kalman filter for the purpose of state estimation, we propose to use the linear Kalman filter operating directly with the wrapped phase measurement. The adaptive window width is selected at each pixel based on the local fringe density to strike a balance between the computation time and the noise robustness. In order to retrieve the unwrapped phase, either a line-scanning approach or a quality guided strategy of pixel selection is used depending on the underlying continuous or discontinuous phase distribution, respectively. Simulation and experimental results are provided to demonstrate the applicability of the proposed method.

Self-Tuning Threshold Method for Real-Time Gait Phase Detection Based on Ground Contact Forces Using FSRs

Directory of Open Access Journals (Sweden)

Jing Tang

2018-02-01

Full Text Available This paper presents a novel methodology for detecting the gait phase of human walking on level ground. The previous threshold method (TM sets a threshold to divide the ground contact forces (GCFs into on-ground and off-ground states. However, the previous methods for gait phase detection demonstrate no adaptability to different people and different walking speeds. Therefore, this paper presents a self-tuning triple threshold algorithm (STTTA that calculates adjustable thresholds to adapt to human walking. Two force sensitive resistors (FSRs were placed on the ball and heel to measure GCFs. Three thresholds (i.e., high-threshold, middle-threshold andlow-threshold were used to search out the maximum and minimum GCFs for the self-adjustments of thresholds. The high-threshold was the main threshold used to divide the GCFs into on-ground and off-ground statuses. Then, the gait phases were obtained through the gait phase detection algorithm (GPDA, which provides the rules that determine calculations for STTTA. Finally, the STTTA reliability is determined by comparing the results between STTTA and Mariani method referenced as the timing analysis module (TAM and Lopez–Meyer methods. Experimental results show that the proposed method can be used to detect gait phases in real time and obtain high reliability when compared with the previous methods in the literature. In addition, the proposed method exhibits strong adaptability to different wearers walking at different walking speeds.

Tunable topological phases in photonic and phononic crystals

KAUST Repository

Chen, Zeguo

2018-02-18

Topological photonics/phononics, inspired by the discovery of topological insulators, is a prosperous field of research, in which remarkable one-way propagation edge states are robust against impurities or defect without backscattering. This dissertation discusses the implementation of multiple topological phases in specific designed photonic and phononic crystals. First, it reports a tunable quantum Hall phase in acoustic ring-waveguide system. A new three-band model focused on the topological transitions at the Γ point is studied, which gives the functionality that nontrivial topology can be tuned by changing the strengths of the couplings and/or the broken time-reversal symmetry. The resulted tunable topological edge states are also numerically verified. Second, based on our previous studied acoustic ring-waveguide system, we introduce anisotropy by tuning the couplings along different directions. We find that the bandgap topology is related to the frequency and directions. We report our proposal on a frequency filter designed from such an anisotropic topological phononic crystal. Third, motivated by the recent progress on quantum spin Hall phases, we propose a design of time-reversal symmetry broken quantum spin Hall insulators in photonics, in which a new quantum anomalous Hall phase emerges. It supports a chiral edge state with certain spin orientations, which is robust against the magnetic impurities. We also report the realization of the quantum anomalous Hall phase in phononics.

Proposal of a relationship between dynamic aperture adn intensity evolution in a storage ring

CERN Document Server

Giovannozzi, M

2010-01-01

A scaling law for the time-dependence of the dynamic aperture, i.e., the region of phase space where stable motion occurs, was proposed in previous papers, about ten years ago. The use of fundamental theorems of the theory of dynamical systems allowed showing that the dynamic aperture has a logarithmic dependence on time. In this paper this result, proved by mean of numerical simulations, is used as a basis for deriving a scaling law for the intensity evolution in a storage ring. The proposed scaling law is also tested against experimental data showing a remarkable agreement.

Single shot fringe pattern phase demodulation using Hilbert-Huang transform aided by the principal component analysis.

Science.gov (United States)

Trusiak, Maciej; Służewski, Łukasz; Patorski, Krzysztof

2016-02-22

Hybrid single shot algorithm for accurate phase demodulation of complex fringe patterns is proposed. It employs empirical mode decomposition based adaptive fringe pattern enhancement (i.e., denoising, background removal and amplitude normalization) and subsequent boosted phase demodulation using 2D Hilbert spiral transform aided by the Principal Component Analysis method for novel, correct and accurate local fringe direction map calculation. Robustness to fringe pattern significant noise, uneven background and amplitude modulation as well as local fringe period and shape variations is corroborated by numerical simulations and experiments. Proposed automatic, adaptive, fast and comprehensive fringe analysis solution compares favorably with other previously reported techniques.

TWRS Privatization Phase I waste characterization data evaluation for the request for proposal

Energy Technology Data Exchange (ETDEWEB)

Patello, G.K.; Wiemers, K.D.

1996-09-01

Radioactive wastes have been stored in large underground tanks at Hanford since 1944. In 1991, The Tank Waste Remediation System (TWRS) program was established to manage, retrieve, treat, immobilize, and dispose of these wastes in a safe, effective manner. DOE believes that it is feasible to privatize portions of the TWRS program. Under the Privatization strategy embodied in the request for proposal, DOE will purchase services from a contractor-owned, contractor-operated facility under a fixed-price type of contract. Phase I is a proof-of- concept/commercial demonstration-scale effort. Method used to achieve the objective of producing a technically reviewed inventory is outlined. Organic speciation and physical properties were gathered for the tank wastes and may be found in the individual tank section of this document; reference reviews and tank volume and sampling summary graphs are also provided for each tank.

TWRS Privatization Phase I waste characterization data evaluation for the request for proposal

International Nuclear Information System (INIS)

Patello, G.K.; Wiemers, K.D.

1996-09-01

Radioactive wastes have been stored in large underground tanks at Hanford since 1944. In 1991, The Tank Waste Remediation System (TWRS) program was established to manage, retrieve, treat, immobilize, and dispose of these wastes in a safe, effective manner. DOE believes that it is feasible to privatize portions of the TWRS program. Under the Privatization strategy embodied in the request for proposal, DOE will purchase services from a contractor-owned, contractor-operated facility under a fixed-price type of contract. Phase I is a proof-of- concept/commercial demonstration-scale effort. Method used to achieve the objective of producing a technically reviewed inventory is outlined. Organic speciation and physical properties were gathered for the tank wastes and may be found in the individual tank section of this document; reference reviews and tank volume and sampling summary graphs are also provided for each tank

Phase I/II study of gefitinib (Iressa(®)) and vorinostat (IVORI) in previously treated patients with advanced non-small cell lung cancer.

Science.gov (United States)

Han, Ji-Youn; Lee, Soo Hyun; Lee, Geon Kook; Yun, Tak; Lee, Young Joo; Hwang, Kum Hui; Kim, Jin Young; Kim, Heung Tae

2015-03-01

Vorinostat has been shown to overcome resistance to gefitinib. We performed a phase I/II study combining gefitinib with vorinostat in previously treated non-small cell lung cancer (NSCLC). A 3 + 3 dose-escalation design was used to determine maximum tolerated dose (MTD) and recommended phase II dose (RP2D). Three dose levels were tested: 250 mg/day gefitinib on days 1-28 and 200, 300 or 400 mg/day vorinostat on days 1-7, and 15-21 out of every 28 days. The primary endpoint was median progression-free survival (PFS). Fifty-two patients were enrolled and treated (43 in phase II). The median age was 59 years, 28 patients were male, 44 had adenocarcinoma, 29 had never smoked, and 36 had undergone one prior treatment. Twenty-two patients exhibited sensitive EGFR mutations. Planned dose escalation was completed without reaching the MTD. The RP2D was 250 mg gefitinib and 400 mg vorinostat. In 43 assessable patients in phase II, the median PFS was 3.2 months; the overall survival (OS) was 19.0 months. There were 16 partial responses and six cases of stable disease. In EGFR-mutant NSCLC, response rate was 77 %, median PFS was 9.1 months, and median OS was 24.1 months. The most common adverse events were anorexia and diarrhea. Treatment with 250 mg gefitinib daily with biweekly 400 mg/day vorinostat was feasible and well tolerated. In an unselected patient population, this combination dose did not improve PFS. However, this combination showed a potential for improving efficacy of gefitinib in EGFR-mutant NSCLC (NCT01027676).

First principles study of the optical contrast in phase change materials

Energy Technology Data Exchange (ETDEWEB)

Caravati, S; Parrinello, M [Department of Chemistry and Applied Biosciences, ETH Zurich, USI Campus, Via Giuseppe Buffi 13, 6900 Lugano (Switzerland); Bernasconi, M, E-mail: marco.bernasconi@mater.unimib.i [Dipartimento di Scienza dei Materiali, Universita di Milano-Bicocca, Via R Cozzi 53, I-20125, Milano (Italy)

2010-08-11

We study from first principles the optical properties of the phase change materials Ge{sub 2}Sb{sub 2}Te{sub 5} (GST), GeTe and Sb{sub 2}Te{sub 3} in the crystalline phase and in realistic models of the amorphous phase generated by quenching from the melt in ab initio molecular dynamics simulations. The calculations reproduce the strong optical contrast between the crystalline and amorphous phases measured experimentally and exploited in optical data storage. It is demonstrated that the optical contrast is due to a change in the optical matrix elements across the phase change in all the compounds. It is concluded that the reduction of the optical matrix elements in the amorphous phases is due to angular disorder in p-bonding which dominates the amorphous network in agreement with previous proposals (Huang and Robertson 2010 Phys. Rev. B 81 081204) based on calculations on crystalline models.

Methodology Proposal for Increasing Swift Trust within Virtual Teams in the Inception Phase of a Project Life-Cycle: Project Manager’s Perspective

Directory of Open Access Journals (Sweden)

Milovanović Bojan Morić

2015-12-01

Full Text Available This paper proposes team building methodology for project managers in virtual teams as means to develop swift trust between new team members in the inception phase of the project life cycle. Proposed methodology encompasses activities within the first three days after the team formation and proposes the measuring tools for monitoring and managing trust development within the project team. Aim of this paper is to provide new insights to various decision makers potentially interested in increasing the performance of project teams operating in virtual environment, such as: investors, business owners and project managers working in virtual environment.

An efficient reconstruction algorithm for differential phase-contrast tomographic images from a limited number of views

International Nuclear Information System (INIS)

Sunaguchi, Naoki; Yuasa, Tetsuya; Gupta, Rajiv; Ando, Masami

2015-01-01

The main focus of this paper is reconstruction of tomographic phase-contrast image from a set of projections. We propose an efficient reconstruction algorithm for differential phase-contrast computed tomography that can considerably reduce the number of projections required for reconstruction. The key result underlying this research is a projection theorem that states that the second derivative of the projection set is linearly related to the Laplacian of the tomographic image. The proposed algorithm first reconstructs the Laplacian image of the phase-shift distribution from the second-derivative of the projections using total variation regularization. The second step is to obtain the phase-shift distribution by solving a Poisson equation whose source is the Laplacian image previously reconstructed under the Dirichlet condition. We demonstrate the efficacy of this algorithm using both synthetically generated simulation data and projection data acquired experimentally at a synchrotron. The experimental phase data were acquired from a human coronary artery specimen using dark-field-imaging optics pioneered by our group. Our results demonstrate that the proposed algorithm can reduce the number of projections to approximately 33% as compared with the conventional filtered backprojection method, without any detrimental effect on the image quality

Long-range correlation in synchronization and syncopation tapping: a linear phase correction model.

Directory of Open Access Journals (Sweden)

Didier Delignières

Full Text Available We propose in this paper a model for accounting for the increase in long-range correlations observed in asynchrony series in syncopation tapping, as compared with synchronization tapping. Our model is an extension of the linear phase correction model for synchronization tapping. We suppose that the timekeeper represents a fractal source in the system, and that a process of estimation of the half-period of the metronome, obeying a random-walk dynamics, combines with the linear phase correction process. Comparing experimental and simulated series, we show that our model allows accounting for the experimentally observed pattern of serial dependence. This model complete previous modeling solutions proposed for self-paced and synchronization tapping, for a unifying framework of event-based timing.

Detecting phase synchronization between coupled non-phase-coherent oscillators

International Nuclear Information System (INIS)

Follmann, Rosangela; Macau, Elbert E.N.; Rosa, Epaminondas

2009-01-01

We compare two methods for detecting phase synchronization in coupled non-phase-coherent oscillators. One method is based on the locking of self-sustained oscillators with an irregular signal. The other uses trajectory recurrences in phase space. We identify the pros and cons of both methods and propose guidelines to detect phase synchronization in data series.

Phase accuracy evaluation for phase-shifting fringe projection profilometry based on uniform-phase coded image

Science.gov (United States)

Zhang, Chunwei; Zhao, Hong; Zhu, Qian; Zhou, Changquan; Qiao, Jiacheng; Zhang, Lu

2018-06-01

Phase-shifting fringe projection profilometry (PSFPP) is a three-dimensional (3D) measurement technique widely adopted in industry measurement. It recovers the 3D profile of measured objects with the aid of the fringe phase. The phase accuracy is among the dominant factors that determine the 3D measurement accuracy. Evaluation of the phase accuracy helps refine adjustable measurement parameters, contributes to evaluating the 3D measurement accuracy, and facilitates improvement of the measurement accuracy. Although PSFPP has been deeply researched, an effective, easy-to-use phase accuracy evaluation method remains to be explored. In this paper, methods based on the uniform-phase coded image (UCI) are presented to accomplish phase accuracy evaluation for PSFPP. These methods work on the principle that the phase value of a UCI can be manually set to be any value, and once the phase value of a UCI pixel is the same as that of a pixel of a corresponding sinusoidal fringe pattern, their phase accuracy values are approximate. The proposed methods provide feasible approaches to evaluating the phase accuracy for PSFPP. Furthermore, they can be used to experimentally research the property of the random and gamma phase errors in PSFPP without the aid of a mathematical model to express random phase error or a large-step phase-shifting algorithm. In this paper, some novel and interesting phenomena are experimentally uncovered with the aid of the proposed methods.

Phase shifts in the Fourier spectra of phase gratings and phase grids: an application for one-shot phase-shifting interferometry.

Science.gov (United States)

Toto-Arellano, Noel-Ivan; Rodriguez-Zurita, Gustavo; Meneses-Fabian, Cruz; Vazquez-Castillo, Jose F

2008-11-10

Among several techniques, phase shifting interferometry can be implemented with a grating used as a beam divider to attain several interference patterns around each diffraction order. Because each pattern has to show a different phase-shift, a suitable shifting technique must be employed. Phase gratings are attractive to perform the former task due to their higher diffraction efficiencies. But as is very well known, the Fourier coefficients of only-phase gratings are integer order Bessel functions of the first kind. The values of these real-valued functions oscillate around zero, so they can adopt negative values, thereby introducing phase shifts of pi at certain diffraction orders. Because this almost trivial fact seems to have been overlooked in the literature regarding its practical implications, in this communication such phase shifts are stressed in the description of interference patterns obtained with grating interferometers. These patterns are obtained by placing two windows in the object plane of a 4f system with a sinusoidal grating/grid in the Fourier plane. It is shown that the corresponding experimental observations of the fringe modulation, as well as the corresponding phase measurements, are all in agreement with the proposed description. A one-shot phase shifting interferometer is finally proposed taking into account these properties after proper incorporation of modulation of polarization.

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

DEFF Research Database (Denmark)

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

2015-01-01

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

Two-step phase retrieval algorithm based on the quotient of inner products of phase-shifting interferograms

International Nuclear Information System (INIS)

Niu, Wenhu; Zhong, Liyun; Sun, Peng; Zhang, Wangping; Lu, Xiaoxu

2015-01-01

Based on the quotient of inner products, a simple and rapid algorithm is proposed to retrieve the measured phase from two-frame phase-shifting interferograms with unknown phase shifts. Firstly, we filtered the background of interferograms by a Gaussian high-pass filter. Secondly, we calculated the inner products of the background-filtered interferograms. Thirdly, we extracted the phase shifts by the quotient of the inner products then calculated the measured phase by an arctangent function. Finally, we tested the performance of the proposed algorithm by the simulation calculation and the experimental research for a vortex phase plate. Both the simulation calculation and the experimental result showed that the phase shifts and the measured phase with high accuracy can be obtained by the proposed algorithm rapidly and conveniently. (paper)

Phase Equilibrium of TiO2 Nanocrystals in Flame-Assisted Chemical Vapor Deposition.

Science.gov (United States)

Liu, Changran; Camacho, Joaquin; Wang, Hai

2018-01-19

Nano-scale titanium oxide (TiO 2 ) is a material useful for a wide range of applications. In a previous study, we showed that TiO 2 nanoparticles of both rutile and anatase crystal phases could be synthesized over the size range of 5 to 20 nm in flame-assisted chemical vapor deposition. Rutile was unexpectedly dominant in oxygen-lean synthesis conditions, whereas anatase is the preferred phase in oxygen-rich gases. The observation is in contrast to the 14 nm rutile-anatase crossover size derived from the existing crystal-phase equilibrium model. In the present work, we made additional measurements over a wider range of synthesis conditions; the results confirm the earlier observations. We propose an improved model for the surface energy that considers the role of oxygen desorption at high temperatures. The model successfully explains the observations made in the current and previous work. The current results provide a useful path to designing flame-assisted chemical vapor deposition of TiO 2 nanocrystals with controllable crystal phases. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Phase Difference Measurement Method Based on Progressive Phase Shift

Directory of Open Access Journals (Sweden)

Min Zhang

2018-06-01

Full Text Available This paper proposes a method for phase difference measurement based on the principle of progressive phase shift (PPS. A phase difference measurement system based on PPS and implemented in the FPGA chip is proposed and tested. In the realized system, a fully programmable delay line (PDL is constructed, which provides accurate and stable delay, benefitting from the feed-back structure of the control module. The control module calibrates the delay according to process, voltage and temperature (PVT variations. Furthermore, a modified method based on double PPS is incorporated to improve the resolution. The obtained resolution is 25 ps. Moreover, to improve the resolution, the proposed method is implemented on the 20 nm Xilinx Kintex Ultrascale platform, and test results indicate that the obtained measurement error and clock synchronization error is within the range of ±5 ps.

Phase retrieval for X-ray in-line phase contrast imaging

International Nuclear Information System (INIS)

Scattarella, F.; Bellotti, R.; Tangaro, S.; Gargano, G.; Giannini, C.

2011-01-01

A review article about phase retrieval problem in X-ray phase contrast imaging is presented. A simple theoretical framework of Fresnel diffraction imaging by X-rays is introduced. A review of the most important methods for phase retrieval in free-propagation-based X-ray imaging and a new method developed by our collaboration are shown. The proposed algorithm, Combined Mixed Approach (CMA) is based on a mixed transfer function and transport of intensity approach, and it requires at most an initial approximate estimate of the average phase shift introduced by the object as prior knowledge. The accuracy with which this initial estimate is known determines the convenience speed of algorithm. The new proposed algorithm is based on the retrieval of both the object phase and its complex conjugate. The results obtained by the algorithm on simulated data have shown that the obtained reconstructed phase maps are characterized by particularly low normalized mean square errors. The algorithm was also tested on noisy experimental phase contrast data, showing a good efficiency in recovering phase information and enhancing the visibility of details inside soft tissues.

A Conceptual Model for Shear-Induced Phase Behavior in Crystallizing Cocoa Butter

International Nuclear Information System (INIS)

Mazzanti, G.; Guthrie, S.; Marangoni, A.; Idziak, S.

2007-01-01

We propose a conceptual model to explain the quantitative data from synchrotron X-ray diffraction experiments on the shear-induced phase behavior of cocoa butter, the main structural component of chocolate. We captured two-dimensional diffraction patterns from cocoa butter at crystallization temperatures of 17.5, 20.0, and 22.5 o C under shear rates from 45 to 1440 s -1 and under static conditions. From the simultaneous analysis of the integrated intensity, correlation length, lamellar thickness, and crystalline orientation, we postulate a conceptual model to provide an explanation for the distribution of phases II, IV, V, and X and the kinetics of the process. As previously proposed in the literature, we assume that the crystallites grow layer upon layer of slightly different composition. The shear rate and temperature applied define these compositions. Simultaneously, the shear and temperature define the crystalline interface area available for secondary nucleation by promoting segregation and affecting the size distribution of the crystallites. The combination of these factors (composition, area, and size distribution) favors dramatically the early onset of phase V under shear and determines the proportions of phases II, IV, V, and X after the transition. The experimental observations, the methodology used, and the proposed explanation are of fundamental and industrial interest, since the structural properties of crystalline networks are determined by their microstructure and polymorphic crystalline state. Different proportions of the phases will thus result in different characteristics of the final material

TWRS privatization phase 1 monitoring wells engineering study

International Nuclear Information System (INIS)

Williams, B.A.; Newcomer, D.R.

1998-04-01

This engineering study provides an evaluation of existing wells and boreholes (wells) within the proposed location for the Tank Waste Remediation System (TWRS) Privatization Phase 1 demonstration site. Phase 1 is part of the TWRS program that was established to manage, retrieve, treat, immobilize, and dispose of high-level waste stored in underground tanks at the Hanford Site. This evaluation is to determine which wells will remain active within the demonstration site based on regulatory, programmatic, or other beneficial use requirements. An initial evaluation of wells within the demonstration site was conducted in 1996. However, changes in construction plans and expansion of the demonstration site necessitated a reevaluation and reclassification of the wells that are within the expanded site. Impacted wells include many of those previously evaluated as well as additional wells identified in or near the expansion areas. Thirty-three wells exist within and immediately adjacent to the identified boundary of the proposed demonstration site. The wells identified for decommissioning will be abandoned according to the well decommissioning plan. Future well requirements within the site include replacement wells for those wells impacted by construction activities, replacements for Resource Conservation and Recovery Act of 1976 (RCRA) wells going dry, and a new characterization well installed to support a TWRS Phase 2 site assessment

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

Science.gov (United States)

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

2018-06-01

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

Phase-only optical encryption based on the zeroth-order phase-contrast technique

Science.gov (United States)

Pizolato, José Carlos; Neto, Luiz Gonçalves

2009-09-01

A phase-only encryption/decryption scheme with the readout based on the zeroth-order phase-contrast technique (ZOPCT), without the use of a phase-changing plate on the Fourier plane of an optical system based on the 4f optical correlator, is proposed. The encryption of a gray-level image is achieved by multiplying the phase distribution obtained directly from the gray-level image by a random phase distribution. The robustness of the encoding is assured by the nonlinearity intrinsic to the proposed phase-contrast method and the random phase distribution used in the encryption process. The experimental system has been implemented with liquid-crystal spatial modulators to generate phase-encrypted masks and a decrypting key. The advantage of this method is the easy scheme to recover the gray-level information from the decrypted phase-only mask applying the ZOPCT. An analysis of this decryption method was performed against brute force attacks.

Theoretical extension and experimental demonstration of spectral compression in second-harmonic generation by Fresnel-inspired binary phase shaping

Science.gov (United States)

Li, Baihong; Dong, Ruifang; Zhou, Conghua; Xiang, Xiao; Li, Yongfang; Zhang, Shougang

2018-05-01

Selective two-photon microscopy and high-precision nonlinear spectroscopy rely on efficient spectral compression at the desired frequency. Previously, a Fresnel-inspired binary phase shaping (FIBPS) method was theoretically proposed for spectral compression of two-photon absorption and second-harmonic generation (SHG) with a square-chirped pulse. Here, we theoretically show that the FIBPS can introduce a negative quadratic frequency phase (negative chirp) by analogy with the spatial-domain phase function of Fresnel zone plate. Thus, the previous theoretical model can be extended to the case where the pulse can be transformed limited and in any symmetrical spectral shape. As an example, we experimentally demonstrate spectral compression in SHG by FIBPS for a Gaussian transform-limited pulse and show good agreement with the theory. Given the fundamental pulse bandwidth, a narrower SHG bandwidth with relatively high intensity can be obtained by simply increasing the number of binary phases. The experimental results also verify that our method is superior to that proposed in [Phys. Rev. A 46, 2749 (1992), 10.1103/PhysRevA.46.2749]. This method will significantly facilitate the applications of selective two-photon microscopy and spectroscopy. Moreover, as it can introduce negative dispersion, hence it can also be generalized to other applications in the field of dispersion compensation.

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.

SAFETY AND ACTIVITY OF TEMSIROLIMUS AND BEVACIZUMAB IN PATIENTS WITH ADVANCED RENAL CELL CARCINOMA PREVIOUSLY TREATED WITH TYROSINE KINASE INHIBITORS: A PHASE 2 CONSORTIUM STUDY

Science.gov (United States)

Merchan, Jaime R.; Qin, Rui; Pitot, Henry; Picus, Joel; Liu, Glenn; Fitch, Tom; Maples, William J.; Flynn, Patrick J.; Fruth, Briant F.; Erlichman, Charles

2015-01-01

Purpose Bevacizumab or Temsirolimus regimens have clinical activity in the first line treatment of advanced renal cell carcinoma (RCC). This phase I/II trial was conducted to determine the safety of combining both agents and its efficacy in RCC patients who progressed on at least one prior anti-VEGF receptor tyrosine kinase inhibitor (RTKI) agent. Methods In the phase I portion, eligible patients were treated with Temsirolimus (25 mg IV weekly) and escalating doses of IV Bevacizumab (level 1=5mg/kg; level 2=10 mg/kg) every other week. The primary endpoint for the phase II portion (RTKI resistant patients) was the 6-month progression free rate. Secondary endpoints were response rate, toxicity evaluation, PFS and OS. Results MTD was not reached at the maximum dose administered in 12 phase I patients. Forty evaluable patients were treated with the phase II recommended dose (Temsirolimus 25 mg IV weekly and Bevacizumab 10 mg/kg IV every two weeks). The 6-month progression free rate was 40% (16/40 pts). Median PFS was 5.9 (4-7.8) months, and median OS was 20.6 (11.5-23.7) months. Partial response/stable/progressive disease were seen in 23%/63%/14% of patients. Most common grade 3-4 AEs included fatigue (17.8%), hypertriglyceridemia (11.1%), stomatitis (8.9%), proteinuria (8.9%), abdominal pain (6.7%), and anemia (6.7%). Baseline levels of serum sFLT-1 and VEGF-A were inversely correlated with PFS and OS, respectively. Conclusions Temsirolimus and Bevacizumab is a feasible combination in patients with advanced RCC previously exposed to oral anti-VEGF agents. The safety and efficacy results warrant further confirmatory studies in this patient population. PMID:25556030

Kidnapping Detection and Recognition in Previous Unknown Environment

Directory of Open Access Journals (Sweden)

Yang Tian

2017-01-01

Full Text Available An unaware event referred to as kidnapping makes the estimation result of localization incorrect. In a previous unknown environment, incorrect localization result causes incorrect mapping result in Simultaneous Localization and Mapping (SLAM by kidnapping. In this situation, the explored area and unexplored area are divided to make the kidnapping recovery difficult. To provide sufficient information on kidnapping, a framework to judge whether kidnapping has occurred and to identify the type of kidnapping with filter-based SLAM is proposed. The framework is called double kidnapping detection and recognition (DKDR by performing two checks before and after the “update” process with different metrics in real time. To explain one of the principles of DKDR, we describe a property of filter-based SLAM that corrects the mapping result of the environment using the current observations after the “update” process. Two classical filter-based SLAM algorithms, Extend Kalman Filter (EKF SLAM and Particle Filter (PF SLAM, are modified to show that DKDR can be simply and widely applied in existing filter-based SLAM algorithms. Furthermore, a technique to determine the adapted thresholds of metrics in real time without previous data is presented. Both simulated and experimental results demonstrate the validity and accuracy of the proposed method.

Phase modulated high density collinear holographic data storage system with phase-retrieval reference beam locking and orthogonal reference encoding.

Science.gov (United States)

Liu, Jinpeng; Horimai, Hideyoshi; Lin, Xiao; Huang, Yong; Tan, Xiaodi

2018-02-19

A novel phase modulation method for holographic data storage with phase-retrieval reference beam locking is proposed and incorporated into an amplitude-encoding collinear holographic storage system. Unlike the conventional phase retrieval method, the proposed method locks the data page and the corresponding phase-retrieval interference beam together at the same location with a sequential recording process, which eliminates piezoelectric elements, phase shift arrays and extra interference beams, making the system more compact and phase retrieval easier. To evaluate our proposed phase modulation method, we recorded and then recovered data pages with multilevel phase modulation using two spatial light modulators experimentally. For 4-level, 8-level, and 16-level phase modulation, we achieved the bit error rate (BER) of 0.3%, 1.5% and 6.6% respectively. To further improve data storage density, an orthogonal reference encoding multiplexing method at the same position of medium is also proposed and validated experimentally. We increased the code rate of pure 3/16 amplitude encoding method from 0.5 up to 1.0 and 1.5 using 4-level and 8-level phase modulation respectively.

Crystalline phases by an improved gradient expansion technique

Science.gov (United States)

Carignano, S.; Mannarelli, M.; Anzuini, F.; Benhar, O.

2018-02-01

We develop an innovative technique for studying inhomogeneous phases with a spontaneous broken symmetry. The method relies on the knowledge of the exact form of the free energy in the homogeneous phase and on a specific gradient expansion of the order parameter. We apply this method to quark matter at vanishing temperature and large chemical potential, which is expected to be relevant for astrophysical considerations. The method is remarkably reliable and fast as compared to performing the full numerical diagonalization of the quark Hamiltonian in momentum space and is designed to improve the standard Ginzburg-Landau expansion close to the phase transition points. For definiteness, we focus on inhomogeneous chiral symmetry breaking, accurately reproducing known results for one-dimensional and two-dimensional modulations and examining novel crystalline structures, as well. Consistently with previous results, we find that the energetically favored modulation is the so-called one-dimensional real-kink crystal. We propose a qualitative description of the pairing mechanism to motivate this result.

Phase-step retrieval for tunable phase-shifting algorithms

Science.gov (United States)

Ayubi, Gastón A.; Duarte, Ignacio; Perciante, César D.; Flores, Jorge L.; Ferrari, José A.

2017-12-01

Phase-shifting (PS) is a well-known technique for phase retrieval in interferometry, with applications in deflectometry and 3D-profiling, which requires a series of intensity measurements with certain phase-steps. Usually the phase-steps are evenly spaced, and its knowledge is crucial for the phase retrieval. In this work we present a method to extract the phase-step between consecutive interferograms. We test the proposed technique with images corrupted by additive noise. The results were compared with other known methods. We also present experimental results showing the performance of the method when spatial filters are applied to the interferograms and the effect that they have on their relative phase-steps.

OSQAR-CHASE Proposal

CERN Document Server

(Pugnat, P; (Sulc, M

2015-01-01

For 2015, the OSQAR collaboration will focus on a new proposal for the search of chameleon, a hypothetical scalar particle postulated as a dark energy candidate with an environment-dependant mass. The required experimental set-up has been successfully tested and validated in 2014 at the SM-18 experimental hall. This proposal will focus on the sensitivity that can be reached during the OSQAR chameleon run in 2015 as well as to possible upgrade phases of the experiment for the coming years.

QPSK regeneration without active phase-locking

DEFF Research Database (Denmark)

Kjøller, Niels-Kristian; Da Ros, Francesco; Røge, Kasper Meldgaard

2016-01-01

QPSK regeneration without active phase stabilization is investigated in numerical simulations. We propose an improved scheme for phase-locking free QPSK regeneration showing significant improvements in the error vector magnitude of the signal.......QPSK regeneration without active phase stabilization is investigated in numerical simulations. We propose an improved scheme for phase-locking free QPSK regeneration showing significant improvements in the error vector magnitude of the signal....

Competing failure analysis in phased-mission systems with multiple functional dependence groups

International Nuclear Information System (INIS)

Wang, Chaonan; Xing, Liudong; Peng, Rui; Pan, Zhusheng

2017-01-01

A phased-mission system (PMS) involves multiple, consecutive, non-overlapping phases of operation. The system structure function and component failure behavior in a PMS can change from phase to phase, posing big challenges to the system reliability analysis. Further complicating the problem is the functional dependence (FDEP) behavior where the failure of certain component(s) causes other component(s) to become unusable or inaccessible or isolated. Previous studies have shown that FDEP can cause competitions between failure propagation and failure isolation in the time domain. While such competing failure effects have been well addressed in single-phase systems, only little work has focused on PMSs with a restrictive assumption that a single FDEP group exists in one phase of the mission. Many practical systems (e.g., computer systems and networks), however may involve multiple FDEP groups during the mission. Moreover, different FDEP groups can be dependent due to sharing some common components; they may appear in a single phase or multiple phases. This paper makes new contributions by modeling and analyzing reliability of PMSs subject to multiple FDEP groups through a Markov chain-based methodology. Propagated failures with both global and selective effects are considered. Four case studies are presented to demonstrate application of the proposed method. - Highlights: • Reliability of phased-mission systems subject to competing failure propagation and isolation effects is modeled. • Multiple independent or dependent functional dependence groups are considered. • Propagated failures with global effects and selective effects are studied. • Four case studies demonstrate generality and application of the proposed Markov-based method.

A three-phase model proposal for the evolution of scientific communication: from first print periodicals to current electronic communication system

Directory of Open Access Journals (Sweden)

Patrícia Bertin

Full Text Available Scientific communication has undergone deep transformations, since the emergence of Internet. Aiming to provide further thought on the evolution of scientific communication, this paper features a historical overview of the scientific communication advances over the last twenty years through a three-phase model for the evolution of the electronic journal and the preprints services, and presents Brazilian contemporary panorama for scientific communication. The three-phase model presented in this work is an adaptation of that one proposed by Tenopir et al. (2003 to describe the patterns of journal use by scientists since 1990. The early evolutionary phase followed the emergence of the first digital journals and the creation of repositories in the Web for publishing preliminary versions of scientific literature on the author’s initiative; by that time, most academics reproved electronic publishing initiatives. From 1996 and forward, in the consolidation phase, electronic journals were commonly identical to their print counterparts; the acceptance of the electronic format began to increase, and preprint services got underway in several disciplines. The advanced evolutionary phase started with the world discussion on open access to scientific information. The comparison of the current electronic journal with that viewed by enthusiasts in the first years of the 1990s shows that some aspects still remain to be improved in electronic formal and informal communication, towards effective dissemination of scientific information.

Online Phase Detection Using Wearable Sensors for Walking with a Robotic Prosthesis

Directory of Open Access Journals (Sweden)

Maja Goršič

2014-02-01

Full Text Available This paper presents a gait phase detection algorithm for providing feedback in walking with a robotic prosthesis. The algorithm utilizes the output signals of a wearable wireless sensory system incorporating sensorized shoe insoles and inertial measurement units attached to body segments. The principle of detecting transitions between gait phases is based on heuristic threshold rules, dividing a steady-state walking stride into four phases. For the evaluation of the algorithm, experiments with three amputees, walking with the robotic prosthesis and wearable sensors, were performed. Results show a high rate of successful detection for all four phases (the average success rate across all subjects >90%. A comparison of the proposed method to an off-line trained algorithm using hidden Markov models reveals a similar performance achieved without the need for learning dataset acquisition and previous model training.

Fiber-based coherent polarization beam combining with cascaded phase-locking and polarization-transforming controls

Science.gov (United States)

Yang, Yan; Geng, Chao; Li, Feng; Huang, Guan; Li, Xinyang

2018-05-01

In this paper, the fiber-based coherent polarization beam combining (CPBC) with cascaded phase-locking (PL) and polarization-transforming (PT) controls was proposed to combine imbalanced input beams where the number of the input beams is not binary, in which the PL control was performed using the piezoelectric-ring fiber-optic phase compensator, and the PT control was realized by the dynamic polarization controller, simultaneously. The principle of the proposed CPBC was introduced. The performance of the proposed CPBC was analyzed in comparison with the CPBC based on PL control and the CPBC based on PT control. The basic experiment of CPBC of three laser beams was carried out to validate the feasibility of the proposed CPBC, where cascaded controls of PL and PT were implemented based on stochastic parallel gradient descent algorithm. Simulation and experimental results show that the proposed CPBC incorporates the advantages of the two previous CPBC schemes and performs well in the closed loop. Moreover, the expansibility and the application of the proposed CPBC were validated by scaling the CPBC to combine seven laser beams. We believe that the proposed fiber-based CPBC with cascaded PL and PT controls has great potential in free space optical communications employing the multi-aperture receiver with asymmetric structure.

78 FR 33911 - Phased Retirement

Science.gov (United States)

2013-06-05

... to implement phased retirement, a new human resources tool that allows full-time employees to work a..., 582, 831, et al. Phased Retirement; Proposed Rule #0;#0;Federal Register / Vol. 78 , No. 108 / Wednesday, June 5, 2013 / Proposed Rules#0;#0; [[Page 33912

Vertical blind phase search for low-complexity carrier phase recovery of offset-QAM Nyquist WDM transmission

Science.gov (United States)

Lu, Jianing; Fu, Songnian; Tang, Haoyuan; Xiang, Meng; Tang, Ming; Liu, Deming

2017-01-01

Low complexity carrier phase recovery (CPR) scheme based on vertical blind phase search (V-BPS) for M-ary offset quadrature amplitude modulation (OQAM) is proposed and numerically verified. After investigating the constellations of both even and odd samples with respect to the phase noise, we identify that the CPR can be realized by measuring the verticality of constellation with respect to different test phase angles. Then measurement without multiplication in the complex plane is found with low complexity. Furthermore, a two-stage configuration is put forward to further reduce the computational complexity (CC). Compared with our recently proposed modified blind phase search (M-BPS) algorithm, the proposed algorithm shows comparable tolerance of phase noise, but reduces the CC by a factor of 3.81 (or 3.05) in the form of multipliers (or adders), taking the CPR of 16-OQAM into account.

Phase III Study of Cabozantinib in Previously Treated Metastatic Castration-Resistant Prostate Cancer: COMET-1.

Science.gov (United States)

Smith, Matthew; De Bono, Johann; Sternberg, Cora; Le Moulec, Sylvestre; Oudard, Stéphane; De Giorgi, Ugo; Krainer, Michael; Bergman, Andries; Hoelzer, Wolfgang; De Wit, Ronald; Bögemann, Martin; Saad, Fred; Cruciani, Giorgio; Thiery-Vuillemin, Antoine; Feyerabend, Susan; Miller, Kurt; Houédé, Nadine; Hussain, Syed; Lam, Elaine; Polikoff, Jonathan; Stenzl, Arnulf; Mainwaring, Paul; Ramies, David; Hessel, Colin; Weitzman, Aaron; Fizazi, Karim

2016-09-01

Cabozantinib is an inhibitor of kinases, including MET and vascular endothelial growth factor receptors, and has shown activity in men with previously treated metastatic castration-resistant prostate cancer (mCRPC). This blinded phase III trial compared cabozantinib with prednisone in patients with mCRPC. Men with progressive mCRPC after docetaxel and abiraterone and/or enzalutamide were randomly assigned at a two-to-one ratio to cabozantinib 60 mg once per day or prednisone 5 mg twice per day. The primary end point was overall survival (OS). Bone scan response (BSR) at week 12 as assessed by independent review committee was the secondary end point; radiographic progression-free survival (rPFS) and effects on circulating tumor cells (CTCs), bone biomarkers, serum prostate-specific antigen (PSA), and symptomatic skeletal events (SSEs) were exploratory assessments. A total of 1,028 patients were randomly assigned to cabozantinib (n = 682) or prednisone (n = 346). Median OS was 11.0 months with cabozantinib and 9.8 months with prednisone (hazard ratio, 0.90; 95% CI, 0.76 to 1.06; stratified log-rank P = .213). BSR at week 12 favored cabozantinib (42% v 3%; stratified Cochran-Mantel-Haenszel P < .001). rPFS was improved in the cabozantinib group (median, 5.6 v 2.8 months; hazard ratio, 0.48; 95% CI, 0.40 to 0.57; stratified log-rank P < .001). Cabozantinib was associated with improvements in CTC conversion, bone biomarkers, and post-random assignment incidence of SSEs but not PSA outcomes. Grade 3 to 4 adverse events and discontinuations because of adverse events were higher with cabozantinib than with prednisone (71% v 56% and 33% v 12%, respectively). Cabozantinib did not significantly improve OS compared with prednisone in heavily treated patients with mCRPC and progressive disease after docetaxel and abiraterone and/or enzalutamide. Cabozantinib had some activity in improving BSR, rPFS, SSEs, CTC conversions, and bone biomarkers but not PSA outcomes. © 2016 by

Phase II trial of veliparib in patients with previously treated BRCA-mutated pancreas ductal adenocarcinoma.

Science.gov (United States)

Lowery, Maeve A; Kelsen, David P; Capanu, Marinela; Smith, Sloane C; Lee, Jonathan W; Stadler, Zsofia K; Moore, Malcolm J; Kindler, Hedy L; Golan, Talia; Segal, Amiel; Maynard, Hannah; Hollywood, Ellen; Moynahan, MaryEllen; Salo-Mullen, Erin E; Do, Richard Kinh Gian; Chen, Alice P; Yu, Kenneth H; Tang, Laura H; O'Reilly, Eileen M

2018-01-01

BRCA-associated cancers have increased sensitivity to poly(ADP-ribose) polymerase inhibitors (PARPis). This single arm, non-randomised, multicentre phase II trial evaluated the response rate of veliparib in patients with previously treated BRCA1/2- or PALB2-mutant pancreatic adenocarcinoma (PDAC). Patients with stage III/IV PDAC and known germline BRCA1/2 or PALB2 mutation, 1-2 lines of treatment, Eastern Cooperative Oncology Group 0-2, were enrolled. Veliparib was dosed at a volume of 300 mg twice-daily (N = 3), then 400 mg twice-daily (N = 15) days 1-28. The primary end-point was to determine the response rate of veliparib; secondary end-points included progression-free survival (PFS), duration of response, overall survival (OS) and safety. Sixteen patients were enrolled; male N = 8 (50%). Median age was 52 years (range 43-77). Five (31%) had a BRCA1 and 11 (69%) had a BRCA2 mutation. Fourteen (88%) patients had received prior platinum-based therapy. No confirmed partial responses (PRs) were seen: one (6%) unconfirmed PR was observed at 4 months with disease progression (PD) at 6 months; four (25%) had stable disease (SD), whereas 11 (69%) had PD as best response including one with clinical PD. Median PFS was 1.7 months (95% confidence interval [CI] 1.57-1.83) and median OS was 3.1 months (95% CI 1.9-4.1). Six (38%) patients had grade III toxicity, including fatigue (N = 3), haematology (N = 2) and nausea (N = 1). Veliparib was well tolerated, but no confirmed response was observed although four (25%) patients remained on study with SD for ≥ 4 months. Additional strategies in this population are needed, and ongoing trials are evaluating PARPis combined with chemotherapy (NCT01585805) and as a maintenance strategy (NCT02184195). Copyright © 2017 Elsevier Ltd. All rights reserved.

A New Synchronous Reference Frame-Based Method for Single-Phase Shunt Active Power Filters

DEFF Research Database (Denmark)

Monfared, Mohammad; Golestan, Saeed; Guerrero, Josep M.

2013-01-01

This paper deals with the design of a novel method in the synchronous reference frame (SRF) to extract the reference compensating current for single-phase shunt active power filters (APFs). Unlike previous works in the SRF, the proposed method has an innovative feature that it does not need...... the fictitious current signal. Frequency-independent operation, accurate reference current extraction and relatively fast transient response are other key features of the presented strategy. The effectiveness of the proposed method is investigated by means of detailed mathematical analysis. The results confirm...

On the location of the surface-attached globule phase in collapsing polymers

International Nuclear Information System (INIS)

Owczarek, A L; Rechnitzer, A; Krawczyk, J; Prellberg, T

2007-01-01

We investigate the existence and location of the surface phase known as the 'surface-attached globule' (SAG) conjectured previously to exist in lattice models of three-dimensional polymers when they are attached to a wall that has a short-range potential. The bulk phase, where the attractive intra-polymer interactions are strong enough to cause a collapse of the polymer into a liquid-like globule and the wall either has weak attractive or repulsive interactions, is usually denoted desorbed-collapsed or DC. Recently, this DC phase was conjectured to harbour two surface phases separated by a boundary where the bulk free energy is analytic while the surface free energy is singular. The surface phase for more attractive values of the wall interaction is the SAG phase. We discuss in more detail the properties of this proposed surface phase and provide Monte Carlo evidence for self-avoiding walks up to a length 256 that this surface phase most likely does exist. Importantly, we discuss alternatives for the surface phase boundary. In particular, we conclude that this boundary may lie along the zero wall interaction line and the bulk phase boundaries rather than any new phase boundary curve

On the location of the surface-attached globule phase in collapsing polymers

Energy Technology Data Exchange (ETDEWEB)

Owczarek, A L [Department of Mathematics and Statistics, University of Melbourne, Victoria 3010 (Australia); Rechnitzer, A [Department of Mathematics, University of British Columbia, BC V6T-1Z2 (Canada); Krawczyk, J [Department of Mathematics and Statistics, University of Melbourne, Victoria 3010 (Australia); Prellberg, T [School of Mathematical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom)

2007-11-02

We investigate the existence and location of the surface phase known as the 'surface-attached globule' (SAG) conjectured previously to exist in lattice models of three-dimensional polymers when they are attached to a wall that has a short-range potential. The bulk phase, where the attractive intra-polymer interactions are strong enough to cause a collapse of the polymer into a liquid-like globule and the wall either has weak attractive or repulsive interactions, is usually denoted desorbed-collapsed or DC. Recently, this DC phase was conjectured to harbour two surface phases separated by a boundary where the bulk free energy is analytic while the surface free energy is singular. The surface phase for more attractive values of the wall interaction is the SAG phase. We discuss in more detail the properties of this proposed surface phase and provide Monte Carlo evidence for self-avoiding walks up to a length 256 that this surface phase most likely does exist. Importantly, we discuss alternatives for the surface phase boundary. In particular, we conclude that this boundary may lie along the zero wall interaction line and the bulk phase boundaries rather than any new phase boundary curve.

77 FR 58323 - Airworthiness Directives; Gulfstream Aerospace LP (Type Certificate Previously Held by Israel...

Science.gov (United States)

2012-09-20

... Aerospace LP (Type Certificate Previously Held by Israel Aircraft Industries, Ltd.) Airplanes AGENCY... Previously Held by Israel Aircraft Industries, Ltd.) Model Gulfstream G150 airplanes. This proposed AD was.... Discussion The Civil Aviation Authority of Israel (CAAI), which is the aviation authority for Israel, has...

Speedup of minimum discontinuity phase unwrapping algorithm with a reference phase distribution

Science.gov (United States)

Liu, Yihang; Han, Yu; Li, Fengjiao; Zhang, Qican

2018-06-01

In three-dimensional (3D) shape measurement based on phase analysis, the phase analysis process usually produces a wrapped phase map ranging from - π to π with some 2 π discontinuities, and thus a phase unwrapping algorithm is necessary to recover the continuous and nature phase map from which 3D height distribution can be restored. Usually, the minimum discontinuity phase unwrapping algorithm can be used to solve many different kinds of phase unwrapping problems, but its main drawback is that it requires a large amount of computations and has low efficiency in searching for the improving loop within the phase's discontinuity area. To overcome this drawback, an improvement to speedup of the minimum discontinuity phase unwrapping algorithm by using the phase distribution on reference plane is proposed. In this improved algorithm, before the minimum discontinuity phase unwrapping algorithm is carried out to unwrap phase, an integer number K was calculated from the ratio of the wrapped phase to the nature phase on a reference plane. And then the jump counts of the unwrapped phase can be reduced by adding 2K π, so the efficiency of the minimum discontinuity phase unwrapping algorithm is significantly improved. Both simulated and experimental data results verify the feasibility of the proposed improved algorithm, and both of them clearly show that the algorithm works very well and has high efficiency.

Fourier phasing with phase-uncertain mask

International Nuclear Information System (INIS)

Fannjiang, Albert; Liao, Wenjing

2013-01-01

Fourier phasing is the problem of retrieving Fourier phase information from Fourier intensity data. The standard Fourier phase retrieval (without a mask) is known to have many solutions which cause the standard phasing algorithms to stagnate and produce wrong or inaccurate solutions. In this paper Fourier phase retrieval is carried out with the introduction of a randomly fabricated mask in measurement and reconstruction. Highly probable uniqueness of solution, up to a global phase, was previously proved with exact knowledge of the mask. Here the uniqueness result is extended to the case where only rough information about the mask’s phases is assumed. The exponential probability bound for uniqueness is given in terms of the uncertainty-to-diversity ratio of the unknown mask. New phasing algorithms alternating between the object update and the mask update are systematically tested and demonstrated to have the capability of recovering both the object and the mask (within the object support) simultaneously, consistent with the uniqueness result. Phasing with a phase-uncertain mask is shown to be robust with respect to the correlation in the mask as well as the Gaussian and Poisson noises. (paper)

An alternative phase-space distribution to sample initial conditions for classical dynamics simulations

International Nuclear Information System (INIS)

Garcia-Vela, A.

2002-01-01

A new quantum-type phase-space distribution is proposed in order to sample initial conditions for classical trajectory simulations. The phase-space distribution is obtained as the modulus of a quantum phase-space state of the system, defined as the direct product of the coordinate and momentum representations of the quantum initial state. The distribution is tested by sampling initial conditions which reproduce the initial state of the Ar-HCl cluster prepared by ultraviolet excitation, and by simulating the photodissociation dynamics by classical trajectories. The results are compared with those of a wave packet calculation, and with a classical simulation using an initial phase-space distribution recently suggested. A better agreement is found between the classical and the quantum predictions with the present phase-space distribution, as compared with the previous one. This improvement is attributed to the fact that the phase-space distribution propagated classically in this work resembles more closely the shape of the wave packet propagated quantum mechanically

A Novel Phase-Locking-Free Phase Sensitive Amplifier based Regenerator

DEFF Research Database (Denmark)

Kjøller, Niels-Kristian; Røge, Kasper Meldgaard; Guan, Pengyu

2016-01-01

We propose a scheme for phase regeneration of optical binary phase-shift keying (BPSK) data signals based on phase sensitive amplification without active phase-locking. A delay interferometer (DI) is used to convert a BPSK signal impaired by noise to an amplitude modulated signal followed by cross......-locked pumps. As a result, active phase-stabilization is avoided. A proof-of-principle experiment is carried out with a dual-pump degenerate phase sensitive amplifier (PSA), demonstrating regeneration for a 10 Gb/s non-return-to-zero differential BPSK (NRZ-DPSK) data signal degraded by a sinusoidal phase...

Performance of an improved logarithmic phase mask with optimized parameters in a wavefront-coding system.

Science.gov (United States)

Zhao, Hui; Li, Yingcai

2010-01-10

In two papers [Proc. SPIE 4471, 272-280 (2001) and Appl. Opt. 43, 2709-2721 (2004)], a logarithmic phase mask was proposed and proved to be effective in extending the depth of field; however, according to our research, this mask is not that perfect because the corresponding defocused modulation transfer function has large oscillations in the low-frequency region, even when the mask is optimized. So, in a previously published paper [Opt. Lett. 33, 1171-1173 (2008)], we proposed an improved logarithmic phase mask by making a small modification. The new mask can not only eliminate the drawbacks to a certain extent but can also be even less sensitive to focus errors according to Fisher information criteria. However, the performance comparison was carried out with the modified mask not being optimized, which was not reasonable. In this manuscript, we optimize the modified logarithmic phase mask first before analyzing its performance and more convincing results have been obtained based on the analysis of several frequently used metrics.

Model of a Plasmonic Phase Interrogation Probe for Optical Sensing of Hemoglobin in Blood Samples

Science.gov (United States)

Sharma, Anuj K.

2015-11-01

Phase interrogation based surface plasmon resonance (SPR) biosensor is proposed for the determination of Hb concentration. Previous experimental results describing variation of refractive index of human blood with Hb concentration at different wavelengths are considered for design simulations. The biosensor design with silica substrate and gold layer is considered. The sensor's performance is closely analyzed in terms of phase sensitivity and resolution. The influence of operating wavelength on biosensor's performance for Hb measurement is critically investigated, which points to carry out the Hb measurement at a shorter wavelength as phase sensitivity and resolution increase significantly with decrease in wavelength. The results are explained in terms of suitable physical concepts such as radiation damping. Use of contamination-preventing biochemical layer ascertains the stability of measurement with the intended SPR biosensor probe. The simulation results also highlight that the resolution of Hb measurement achievable with the proposed biosensor is much higher compared with several existing methods.

Proposal for nanoscale cascaded plasmonic majority gates for non-Boolean computation.

Science.gov (United States)

Dutta, Sourav; Zografos, Odysseas; Gurunarayanan, Surya; Radu, Iuliana; Soree, Bart; Catthoor, Francky; Naeemi, Azad

2017-12-19

Surface-plasmon-polariton waves propagating at the interface between a metal and a dielectric, hold the key to future high-bandwidth, dense on-chip integrated logic circuits overcoming the diffraction limitation of photonics. While recent advances in plasmonic logic have witnessed the demonstration of basic and universal logic gates, these CMOS oriented digital logic gates cannot fully utilize the expressive power of this novel technology. Here, we aim at unraveling the true potential of plasmonics by exploiting an enhanced native functionality - the majority voter. Contrary to the state-of-the-art plasmonic logic devices, we use the phase of the wave instead of the intensity as the state or computational variable. We propose and demonstrate, via numerical simulations, a comprehensive scheme for building a nanoscale cascadable plasmonic majority logic gate along with a novel referencing scheme that can directly translate the information encoded in the amplitude and phase of the wave into electric field intensity at the output. Our MIM-based 3-input majority gate displays a highly improved overall area of only 0.636 μm 2 for a single-stage compared with previous works on plasmonic logic. The proposed device demonstrates non-Boolean computational capability and can find direct utility in highly parallel real-time signal processing applications like pattern recognition.

Phase diagram of the Fe-Sn-Zr system at 800 °C

International Nuclear Information System (INIS)

Nieva, N.; Corvalán, C.; Jiménez, M.J.; Gómez, A.; Arreguez, C.; Joubert, J.-M.; Arias, D.

2017-01-01

New experimental results on the Fe-Sn-Zr phase diagram at 800 °C are presented, particularly in the central, Fe rich and Sn rich regions of the Gibbs triangle. Seven ternary alloys were designed, produced and examined by different techniques: optical and scanning electron microscopy, semi-quantitative microanalysis, quantitative microanalysis and X-ray diffraction. The results of this work and previous experimental data were used to determine the phase diagram section at 800 °C which contains at least five ternary compounds: Fe 6 Sn 6 Zr, Y, X′, θ and C36. - Highlights: •A phase diagram of Fe-Sn-Zr system at 800 °C is proposed. •The isothermal section of Fe-Sn-Zr system at 800 °C and that at 900 °C determined previously allow reliable extrapolations at low temperatures. •The study at different temperatures (900 °C and 800 °C in this case) is highly desirable because it allows the separation between enthalpic and entropic effects in a future Calphad modelling.

Phase diagram of the Fe-Sn-Zr system at 800 °C

Energy Technology Data Exchange (ETDEWEB)

Nieva, N. [Laboratorio de Física del Sólido, Departamento de Física, Facultad de Ciencias Exactas y Tecnología, Universidad Nacional de Tucumán (Argentina); Corvalán, C., E-mail: corvalan@cnea.gov.ar [Gerencia de Materiales, Comisión Nacional de Energía Atómica Argentina (CNEA), Universidad Nacional de Tres de Febrero, Argentina, CONICET, Consejo Nacional de Ciencia y Técnica (Argentina); Jiménez, M.J. [IFISUR, CONICET, Departamento de Física, Universidad Nacional del Sur, Bahía Blanca (Argentina); Gómez, A. [Grupo LMFAE – PPFAE, Centro Atómico Ezeiza, Comisión Nacional de Energía Atómica (Argentina); Arreguez, C. [Laboratorio de Física del Sólido, Departamento de Física, Facultad de Ciencias Exactas y Tecnología, Universidad Nacional de Tucumán (Argentina); Joubert, J.-M. [Chimie Métallurgique des Terres Rares (CMTR), Institut de Chimie et des Matériaux Paris-Est (ICMPE), CNRS, Université Paris-Est Créteil, 2-8 rue Henri Dunant, 94320 Thiais Cedex (France); Arias, D. [Instituto de Tecnología J. Sabato, Universidad Nacional de San Martín-CNEA (Argentina)

2017-04-15

New experimental results on the Fe-Sn-Zr phase diagram at 800 °C are presented, particularly in the central, Fe rich and Sn rich regions of the Gibbs triangle. Seven ternary alloys were designed, produced and examined by different techniques: optical and scanning electron microscopy, semi-quantitative microanalysis, quantitative microanalysis and X-ray diffraction. The results of this work and previous experimental data were used to determine the phase diagram section at 800 °C which contains at least five ternary compounds: Fe{sub 6}Sn{sub 6}Zr, Y, X′, θ and C36. - Highlights: •A phase diagram of Fe-Sn-Zr system at 800 °C is proposed. •The isothermal section of Fe-Sn-Zr system at 800 °C and that at 900 °C determined previously allow reliable extrapolations at low temperatures. •The study at different temperatures (900 °C and 800 °C in this case) is highly desirable because it allows the separation between enthalpic and entropic effects in a future Calphad modelling.

Spline based iterative phase retrieval algorithm for X-ray differential phase contrast radiography.

Science.gov (United States)

Nilchian, Masih; Wang, Zhentian; Thuering, Thomas; Unser, Michael; Stampanoni, Marco

2015-04-20

Differential phase contrast imaging using grating interferometer is a promising alternative to conventional X-ray radiographic methods. It provides the absorption, differential phase and scattering information of the underlying sample simultaneously. Phase retrieval from the differential phase signal is an essential problem for quantitative analysis in medical imaging. In this paper, we formalize the phase retrieval as a regularized inverse problem, and propose a novel discretization scheme for the derivative operator based on B-spline calculus. The inverse problem is then solved by a constrained regularized weighted-norm algorithm (CRWN) which adopts the properties of B-spline and ensures a fast implementation. The method is evaluated with a tomographic dataset and differential phase contrast mammography data. We demonstrate that the proposed method is able to produce phase image with enhanced and higher soft tissue contrast compared to conventional absorption-based approach, which can potentially provide useful information to mammographic investigations.

Multiplexed phase-space imaging for 3D fluorescence microscopy.

Science.gov (United States)

Liu, Hsiou-Yuan; Zhong, Jingshan; Waller, Laura

2017-06-26

Optical phase-space functions describe spatial and angular information simultaneously; examples of optical phase-space functions include light fields in ray optics and Wigner functions in wave optics. Measurement of phase-space enables digital refocusing, aberration removal and 3D reconstruction. High-resolution capture of 4D phase-space datasets is, however, challenging. Previous scanning approaches are slow, light inefficient and do not achieve diffraction-limited resolution. Here, we propose a multiplexed method that solves these problems. We use a spatial light modulator (SLM) in the pupil plane of a microscope in order to sequentially pattern multiplexed coded apertures while capturing images in real space. Then, we reconstruct the 3D fluorescence distribution of our sample by solving an inverse problem via regularized least squares with a proximal accelerated gradient descent solver. We experimentally reconstruct a 101 Megavoxel 3D volume (1010×510×500µm with NA 0.4), demonstrating improved acquisition time, light throughput and resolution compared to scanning aperture methods. Our flexible patterning scheme further allows sparsity in the sample to be exploited for reduced data capture.

Density Functional Theory for Phase-Ordering Transitions

Energy Technology Data Exchange (ETDEWEB)

Wu, Jianzhong [Univ. of California, Riverside, CA (United States)

2016-03-30

Colloids display astonishing structural and dynamic properties that can be dramatically altered by modest changes in the solution condition or an external field. This complex behavior stems from a subtle balance of colloidal forces and intriguing mesoscopic and macroscopic phase transitions that are sensitive to the processing conditions and the dispersing environment. Whereas the knowledge on the microscopic structure and phase behavior of colloidal systems at equilibrium is now well-advanced, quantitative predictions of the dynamic properties and the kinetics of phase-ordering transitions in colloids are not always realized. Many important mesoscopic and off-equilibrium colloidal states remain poorly understood. The proposed research aims to develop a new, unifying approach to describe colloidal dynamics and the kinetics of phase-ordering transitions based on accomplishments from previous work for the equilibrium properties of both uniform and inhomogeneous systems and on novel concepts from the state-of-the-art dynamic density functional theory. In addition to theoretical developments, computational research is designed to address a number of fundamental questions on phase-ordering transitions in colloids, in particular those pertinent to a competition of the dynamic pathways leading to various mesoscopic structures, off-equilibrium states, and crystalline phases. By providing a generic theoretical framework to describe equilibrium, metastable as well as non-ergodic phase transitions concurrent with the colloidal self-assembly processes, accomplishments from this work will have major impacts on both fundamental research and technological applications.

Assessment of the environmental impact statement for the proposed expansion of the Olympic Dam operations at Roxby Downs

International Nuclear Information System (INIS)

1997-01-01

This Environmental Assessment Report assesses the social, environmental and economic impact of the proposal by Western Mining Corporation (Olympic Dam Corporation) Pty Ltd. (WMC) to increase their production at Olympic Dam mine from 150,000t/a of copper and associated products to 350,000t/a by a phased expansion. The first phase would take production to approximately 200,000t/a. The report reviews the 1997 Environmental Impact Statement (EIS), public comments on the EIS, and the proponent's responses to these comments in the Supplement to the EIS. It also relies on information, comments and advice provided by appropriate South Australian and Commonwealth government agencies (through the joint assessment process) and previous studies undertaken in the region.The focus of the contents of this assessment report are: water usage; tailing management; radiation management; economic and employment estimates; EIS process, regulation and monitoring as well as flora, fauna and town management issues. This report also recognises that the Olympic Dam mine has been subject to previous environmental assessments which resulted in the environmental regime currently in place for the existing operations.It is concluded that the risks to the biophysical, historical, cultural and social environments from the proposed Olympic dam expansion are acceptable provided the mine continues to operate under stringent environmental control

Assessment of the environmental impact statement for the proposed expansion of the Olympic Dam operations at Roxby Downs

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-07-01

This Environmental Assessment Report assesses the social, environmental and economic impact of the proposal by Western Mining Corporation (Olympic Dam Corporation) Pty Ltd. (WMC) to increase their production at Olympic Dam mine from 150,000t/a of copper and associated products to 350,000t/a by a phased expansion. The first phase would take production to approximately 200,000t/a. The report reviews the 1997 Environmental Impact Statement (EIS), public comments on the EIS, and the proponent's responses to these comments in the Supplement to the EIS. It also relies on information, comments and advice provided by appropriate South Australian and Commonwealth government agencies (through the joint assessment process) and previous studies undertaken in the region.The focus of the contents of this assessment report are: water usage; tailing management; radiation management; economic and employment estimates; EIS process, regulation and monitoring as well as flora, fauna and town management issues. This report also recognises that the Olympic Dam mine has been subject to previous environmental assessments which resulted in the environmental regime currently in place for the existing operations.It is concluded that the risks to the biophysical, historical, cultural and social environments from the proposed Olympic dam expansion are acceptable provided the mine continues to operate under stringent environmental control.

Absence of phase-dependent noise in time-domain reflectivity studies of impulsively excited phonons

KAUST Repository

Hussain, A.

2010-06-17

There have been several reports of phase-dependent noise in time-domain reflectivity studies of optical phonons excited by femtosecond laser pulses in semiconductors, semimetals, and superconductors. It was suggested that such behavior is associated with the creation of squeezed phonon states although there is no theoretical model that directly supports such a proposal. We have experimentally re-examined the studies of phonons in bismuth and gallium arsenide, and find no evidence of any phase-dependent noise signature associated with the phonons. We place an upper limit on any such noise at least 40–50 dB lower than previously reported.

Absence of phase-dependent noise in time-domain reflectivity studies of impulsively excited phonons

KAUST Repository

Hussain, A.; Andrews, S. R.

2010-01-01

There have been several reports of phase-dependent noise in time-domain reflectivity studies of optical phonons excited by femtosecond laser pulses in semiconductors, semimetals, and superconductors. It was suggested that such behavior is associated with the creation of squeezed phonon states although there is no theoretical model that directly supports such a proposal. We have experimentally re-examined the studies of phonons in bismuth and gallium arsenide, and find no evidence of any phase-dependent noise signature associated with the phonons. We place an upper limit on any such noise at least 40–50 dB lower than previously reported.

How to quantify the transition phase during golf swing performance: Torsional load affects low back complaints during the transition phase.

Science.gov (United States)

Sim, Taeyong; Choi, Ahnryul; Lee, Soeun; Mun, Joung Hwan

2017-10-01

The transition phase of a golf swing is considered to be a decisive instant required for a powerful swing. However, at the same time, the low back torsional loads during this phase can have a considerable effect on golf-related low back pain (LBP). Previous efforts to quantify the transition phase were hampered by problems with accuracy due to methodological limitations. In this study, vector-coding technique (VCT) method was proposed as a comprehensive methodology to quantify the precise transition phase and examine low back torsional load. Towards this end, transition phases were assessed using three different methods (VCT, lead hand speed and X-factor stretch) and compared; then, low back torsional load during the transition phase was examined. As a result, the importance of accurate transition phase quantification has been documented. The largest torsional loads were observed in healthy professional golfers (10.23 ± 1.69 N · kg -1 ), followed by professional golfers with a history of LBP (7.93 ± 1.79 N · kg -1 ), healthy amateur golfers (1.79 ± 1.05 N · kg -1 ) and amateur golfers with a history of LBP (0.99 ± 0.87 N · kg -1 ), which order was equal to that of the transition phase magnitudes of each group. These results indicate the relationship between the transition phase and LBP history and the dependency of the torsional load magnitude on the transition phase.

Fractional Fourier domain optical image hiding using phase retrieval algorithm based on iterative nonlinear double random phase encoding.

Science.gov (United States)

Wang, Xiaogang; Chen, Wen; Chen, Xudong

2014-09-22

We present a novel image hiding method based on phase retrieval algorithm under the framework of nonlinear double random phase encoding in fractional Fourier domain. Two phase-only masks (POMs) are efficiently determined by using the phase retrieval algorithm, in which two cascaded phase-truncated fractional Fourier transforms (FrFTs) are involved. No undesired information disclosure, post-processing of the POMs or digital inverse computation appears in our proposed method. In order to achieve the reduction in key transmission, a modified image hiding method based on the modified phase retrieval algorithm and logistic map is further proposed in this paper, in which the fractional orders and the parameters with respect to the logistic map are regarded as encryption keys. Numerical results have demonstrated the feasibility and effectiveness of the proposed algorithms.

Proposal of new bonding technique 'Instantaneous Liquid Phase (ILP) Bonding'

International Nuclear Information System (INIS)

Zhang, Yue-Chang; Nakagawa, Hiroji; Matsuda, Fukuhisa.

1987-01-01

A new bonding technique named ''Instantaneous Liquid Phase (ILP) bonding'' suitable mainly for welding dissimilar materials was proposed by which instantaneous melting of one or two of the faying surfaces is utilized. The processes of ILP bonding are mainly consisted of three stages, namely the first stage forming thin liquid layer by rapid heating, the second stage joining both specimens by thin liquid layer, and the third stage cooling the specimens rapidly to avoid the formation of brittle layer. The welding temperatures of the specimens to be welded in ILP bonding are generally differentiated from each other. ILP bonding was applied for a variety of combinations of dissimilar materials of aluminum, aluminum alloys, titanium, titanium alloy, carbon steel, austenitic stainless steel, copper and tungsten, and for similar materials of stainless steel and nickel-base alloy. There were no microvoids in these welding joints, and the formation of brittle layer at the bonding interface was suppressed. The welded joints of Al + Ti, Cu + carbon steel and Cu + austenitic stainless steel showed the fracture in base metal having lower tensile strength. Further, the welded joints of Al + carbon steel, Al alloy + Ti, Al alloy + carbon steel or + austenitic stainless steel, Ti + carbon steel or + austenitic stainless steel showed better tensile properties in the comparison with diffusion welding. Furthermore, ILP bonding was available for welding same materials susceptible to hot cracking. Because of the existence of liquid layer, the welding pressure required was extremely low, and preparation of faying surface by simple tooling or polishing by no.80 emery paper was enough. The change in specimen length before and after welding was relatively little, only depending on the thickness of liquid layer. The welding time was very short, and thus high welding efficiency was obtained. (author)

Some proposals of performance for the management of groundwater in the province of Jaen

International Nuclear Information System (INIS)

Gonzalez Marquez, F. J.

2009-01-01

The object of this document is the basic configuration of a system of work oriented and directed to all the parts interested in the study, the management, the investigation, the use and the operation of underground waters in the province of Jaen, by means of which from a made diagnosis that reflects the present reality, the concretion of the existing problems, the proposal of a series of performances and the essential administrative support, to regularize, to balance and to harness the correct use of the facilities of water pick up, as other types of facilities mining-industrialists, as much in the previous phase (construction) like in later phase (operation, maintenance, etc.) in order to as much approximate us to a suitable regime of sustain ability quantitatively as qualitatively. (Author) 10 refs

Local blur analysis and phase error correction method for fringe projection profilometry systems.

Science.gov (United States)

Rao, Li; Da, Feipeng

2018-05-20

We introduce a flexible error correction method for fringe projection profilometry (FPP) systems in the presence of local blur phenomenon. Local blur caused by global light transport such as camera defocus, projector defocus, and subsurface scattering will cause significant systematic errors in FPP systems. Previous methods, which adopt high-frequency patterns to separate the direct and global components, fail when the global light phenomenon occurs locally. In this paper, the influence of local blur on phase quality is thoroughly analyzed, and a concise error correction method is proposed to compensate the phase errors. For defocus phenomenon, this method can be directly applied. With the aid of spatially varying point spread functions and local frontal plane assumption, experiments show that the proposed method can effectively alleviate the system errors and improve the final reconstruction accuracy in various scenes. For a subsurface scattering scenario, if the translucent object is dominated by multiple scattering, the proposed method can also be applied to correct systematic errors once the bidirectional scattering-surface reflectance distribution function of the object material is measured.

Robust maximum power point tracker using sliding mode controller for the three-phase grid-connected photovoltaic system

Energy Technology Data Exchange (ETDEWEB)

Kim, Il-Song [LG Chem. Ltd./Research park, Mobile Energy R and D, 104-1 Moonji-Dong, Yuseong-Gu, Daejeon 305-380 (Korea)

2007-03-15

A robust maximum power point tracker (MPPT) using sliding mode controller for the three-phase grid-connected photovoltaic system has been proposed in this paper. Contrary to the previous controller, the proposed system consists of MPPT controller and current controller for tight regulation of the current. The proposed MPPT controller generates current reference directly from the solar array power information and the current controller uses the integral sliding mode for the tight control of current. The proposed system can prevent the current overshoot and provide optimal design for the system components. The structure of the proposed system is simple, and it shows robust tracking property against modeling uncertainties and parameter variations. Mathematical modeling is developed and the experimental results verify the validity of the proposed controller. (author)

Hydrodynamic suppression of phase separation in active suspensions.

Science.gov (United States)

Matas-Navarro, Ricard; Golestanian, Ramin; Liverpool, Tanniemola B; Fielding, Suzanne M

2014-09-01

We simulate with hydrodynamics a suspension of active disks squirming through a Newtonian fluid. We explore numerically the full range of squirmer area fractions from dilute to close packed and show that "motility induced phase separation," which was recently proposed to arise generically in active matter, and which has been seen in simulations of active Brownian disks, is strongly suppressed by hydrodynamic interactions. We give an argument for why this should be the case and support it with counterpart simulations of active Brownian disks in a parameter regime that provides a closer counterpart to hydrodynamic suspensions than in previous studies.

Phase diagram of an extended Agassi model

Science.gov (United States)

García-Ramos, J. E.; Dukelsky, J.; Pérez-Fernández, P.; Arias, J. M.

2018-05-01

Background: The Agassi model [D. Agassi, Nucl. Phys. A 116, 49 (1968), 10.1016/0375-9474(68)90482-X] is an extension of the Lipkin-Meshkov-Glick (LMG) model [H. J. Lipkin, N. Meshkov, and A. J. Glick, Nucl. Phys. 62, 188 (1965), 10.1016/0029-5582(65)90862-X] that incorporates the pairing interaction. It is a schematic model that describes the interplay between particle-hole and pair correlations. It was proposed in the 1960s by D. Agassi as a model to simulate the properties of the quadrupole plus pairing model. Purpose: The aim of this work is to extend a previous study by Davis and Heiss [J. Phys. G: Nucl. Phys. 12, 805 (1986), 10.1088/0305-4616/12/9/006] generalizing the Agassi model and analyze in detail the phase diagram of the model as well as the different regions with coexistence of several phases. Method: We solve the model Hamiltonian through the Hartree-Fock-Bogoliubov (HFB) approximation, introducing two variational parameters that play the role of order parameters. We also compare the HFB calculations with the exact ones. Results: We obtain the phase diagram of the model and classify the order of the different quantum phase transitions appearing in the diagram. The phase diagram presents broad regions where several phases, up to three, coexist. Moreover, there is also a line and a point where four and five phases are degenerated, respectively. Conclusions: The phase diagram of the extended Agassi model presents a rich variety of phases. Phase coexistence is present in extended areas of the parameter space. The model could be an important tool for benchmarking novel many-body approximations.

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

International Nuclear Information System (INIS)

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

2016-01-01

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

Clinical Research Environment in India: Challenges and Proposed Solutions.

Science.gov (United States)

Burt, Tal; Sharma, Pooja; Dhillon, Savita; Manchanda, Mukul; Mittal, Sanjay; Trehan, Naresh

2014-11-01

India has compelling need and keen aspirations for indigenous clinical research. Notwithstanding this need and previously reported growth the expected expansion of Indian clinical research has not materialized. We reviewed the scientific literature, lay press reports, and ClinicalTrials.gov data for information and commentary on projections, progress, and impediments associated with clinical trials in India. We also propose targeted solutions to identified challenges. The Indian clinical trial sector grew by (+) 20.3% CAGR (compound annual growth rate) between 2005 and 2010 and contracted by (-) 14.6% CAGR between 2010 and 2013. Phase-1 trials grew by (+) 43.5% CAGR from 2005-2013, phase-2 trials grew by (+) 19.8% CAGR from 2005-2009 and contracted by (-) 12.6% CAGR from 2009-2013, and phase-3 trials grew by (+) 13.0% CAGR from 2005-2010 and contracted by (-) 28.8% CAGR from 2010-2013. This was associated with a slowing of the regulatory approval process, increased media coverage and activist engagement, and accelerated development of regulatory guidelines and recuperative initiatives. We propose the following as potential targets for restorative interventions: Regulatory overhaul (leadership and enforcement of regulations, resolution of ambiguity in regulations, staffing, training, guidelines, and ethical principles [e.g., compensation]).Education and training of research professionals, clinicians, and regulators.Public awareness and empowerment. After a peak in 2009-2010, the clinical research sector in India appears to be experiencing a contraction. There are indications of challenges in regulatory enforcement of guidelines; training of clinical research professionals; and awareness, participation, partnership, and the general image amongst the non-professional media and public. Preventative and corrective principles and interventions are outlined with the goal of realizing the clinical research potential in India.

Kalman filters for real-time magnetic island phase tracking

International Nuclear Information System (INIS)

Borgers, D.P.; Lauret, M.; Baar, M.R. de

2013-01-01

Highlights: • We propose two Kalman filters for tracking of NTMs on ASDEX Upgrade. • The Kalman filters can track NTMs in a much larger frequency range than PLLs. • The filters are tested on synthetic and experimental data from TEXTOR and TCV. • We conclude that the unscented Kalman filter can be useful for NTM control. -- Abstract: For control of neoclassical tearing modes (NTMs) and the resulting rotating magnetic islands in tokamak plasmas, the frequency and phase of the magnetic islands need to be accurately tracked in real-time. In previous experiments on TEXTOR, this was achieved using a phase-locked loop (PLL). For ASDEX Upgrade however, the desired frequency range in which the islands are to be tracked (100 Hz–10 kHz) is much larger than is possible with a PLL. In this contribution, an extended Kalman filter (EKF) and an unscented Kalman filter (UKF) are proposed for real-time frequency, phase and amplitude tracking of sinusoidal signals, based on noisy measurements. Compared to PLLs, the EKF and UKF are able to track sinusoidal signals in a much larger frequency range. The filters are applied on synthetic data and on experimental data from the TEXTOR and TCV tokamaks, from which we conclude that the UKF can be useful for real-time control of magnetic islands on ASDEX Upgrade

Kalman filters for real-time magnetic island phase tracking

Energy Technology Data Exchange (ETDEWEB)

Borgers, D.P. [Hybrid and Networked Systems, Department of Mechanical Engineering – Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Lauret, M., E-mail: M.Lauret@tue.nl [FOM Institute DIFFER – Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, Nieuwegein (Netherlands); Control Systems Technology, Department of Mechanical Engineering – Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Baar, M.R. de [FOM Institute DIFFER – Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Trilateral Euregio Cluster, P.O. Box 1207, Nieuwegein (Netherlands); Control Systems Technology, Department of Mechanical Engineering – Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

2013-11-15

Highlights: • We propose two Kalman filters for tracking of NTMs on ASDEX Upgrade. • The Kalman filters can track NTMs in a much larger frequency range than PLLs. • The filters are tested on synthetic and experimental data from TEXTOR and TCV. • We conclude that the unscented Kalman filter can be useful for NTM control. -- Abstract: For control of neoclassical tearing modes (NTMs) and the resulting rotating magnetic islands in tokamak plasmas, the frequency and phase of the magnetic islands need to be accurately tracked in real-time. In previous experiments on TEXTOR, this was achieved using a phase-locked loop (PLL). For ASDEX Upgrade however, the desired frequency range in which the islands are to be tracked (100 Hz–10 kHz) is much larger than is possible with a PLL. In this contribution, an extended Kalman filter (EKF) and an unscented Kalman filter (UKF) are proposed for real-time frequency, phase and amplitude tracking of sinusoidal signals, based on noisy measurements. Compared to PLLs, the EKF and UKF are able to track sinusoidal signals in a much larger frequency range. The filters are applied on synthetic data and on experimental data from the TEXTOR and TCV tokamaks, from which we conclude that the UKF can be useful for real-time control of magnetic islands on ASDEX Upgrade.

High frequency write head measurement with the phase detection magnetic force microscope

International Nuclear Information System (INIS)

Abe, M.; Tanaka, Y.

2001-01-01

We demonstrated the measurement of the high frequency (HF) magnetic field of a write head with the phase detection magnetic force microscope. An amplitude-modulated current was applied to the head coil to detect the force gradient induced by the HF magnetic field. Spatial resolution of this method was higher than that of the deflection detection method previously proposed. By the phase detection method, dynamic HF magnetic fields at the poles of the write heads were clearly imaged. HF magnetic field leakage was observed along the P2 pole shape on the air-bearing surface. The frequency dependence of the write head dynamics up to 350 MHz was also investigated. [copyright] 2001 American Institute of Physics

Strong coupling phase in QED

International Nuclear Information System (INIS)

Aoki, Ken-ichi

1988-01-01

Existence of a strong coupling phase in QED has been suggested in solutions of the Schwinger-Dyson equation and in Monte Carlo simulation of lattice QED. In this article we recapitulate the previous arguments, and formulate the problem in the modern framework of the renormalization theory, Wilsonian renormalization. This scheme of renormalization gives the best understanding of the basic structure of a field theory especially when it has a multi-phase structure. We resolve some misleading arguments in the previous literature. Then we set up a strategy to attack the strong phase, if any. We describe a trial; a coupled Schwinger-Dyson equation. Possible picture of the strong coupling phase QED is presented. (author)

Three layer model analysis on two-phase critical flow through a converging nozzle

International Nuclear Information System (INIS)

Ochi, J.; Ayukawa, K.

1991-01-01

A three layer model is proposed for a two-phase critical flow through a converging nozzle in this paper. Most previous analyses of the two phase flow have been based on a homogeneous or a separated flow model as the conservation equations. These results were found to have large deviations from the actual measurements for two phase critical flows. The presented model is based on the assumption that a flow consists of three layers with a mixing region between gas and liquid phase layers. The effect of gas and liquid fraction occupied in the mixing layer was made clear from the numerical results. The measurements of the critical flow rate and the pressure profiles through a converging nozzle were made with air-water flow. The calculated results of these models are discussed in comparison with the experimental data for the flow rates and the pressure distributions under critical conditions

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.

The role of non-fig-wasp insects on fig tree biology, with a proposal of the F phase (Fallen figs)

Science.gov (United States)

Palmieri, Luciano; Pereira, Rodrigo Augusto Santinelo

2018-07-01

The two seminal papers by Galil and Eisikowitch describing the development of Ficus flowers and their sycophilous wasps (i.e., phases A-E) have been adopted in several ecological and evolutionary studies on a wide range of fig tree-insect interactions. Their classification, however, is not inclusive enough to encompass all the diversity of insects associated with the fig development, and the impact of this fauna on the fig-fig wasp mutualism is still unexplored. Here we describe the life history of the non-fig-wasp insects and propose an additional phase to fig-development classification, the F phase (Fallen figs). These figs are not consumed by frugivores while still on the parent tree, fall to the ground and turn into a resource for a diverse range of animals. To support the relevance of the F phase, we summarized a 5-years-period of field observations made on different biomes in three continents. Additionally, we compiled data from the literature of non-fig-wasp insects including only insects associated with inflorescences of wild fig tree species. We report 129 species of non-fig-wasp insects feeding on figs; they colonize the figs in different phases of development and some groups rely on the fallen figs to complete their life cycles. Their range of interaction varies from specialists - that use exclusively fig pulp or fig seeds in their diets - to generalists, opportunists and parasitoids species. The formalization of this additional phase will encourage new studies on fig tree ecology and improve our knowledge on the processes that affect the diversification of insects. It will also help us to understand the implications this fauna may have had on the origin and maintenance of mutualistic interactions.

Predicting fruit consumption: the role of habits, previous behavior and mediation effects

NARCIS (Netherlands)

de Vries, H.; Eggers, S.M.; Lechner, L.; van Osch, L.; van Stralen, M.M.

2014-01-01

Background: This study assessed the role of habits and previous behavior in predicting fruit consumption as well as their additional predictive contribution besides socio-demographic and motivational factors. In the literature, habits are proposed as a stable construct that needs to be controlled

The Effects of the Previous Outcome on Probabilistic Choice in Rats

Science.gov (United States)

Marshall, Andrew T.; Kirkpatrick, Kimberly

2014-01-01

This study examined the effects of previous outcomes on subsequent choices in a probabilistic-choice task. Twenty-four rats were trained to choose between a certain outcome (1 or 3 pellets) versus an uncertain outcome (3 or 9 pellets), delivered with a probability of .1, .33, .67, and .9 in different phases. Uncertain outcome choices increased with the probability of uncertain food. Additionally, uncertain choices increased with the probability of uncertain food following both certain-choice outcomes and unrewarded uncertain choices. However, following uncertain-choice food outcomes, there was a tendency to choose the uncertain outcome in all cases, indicating that the rats continued to “gamble” after successful uncertain choices, regardless of the overall probability or magnitude of food. A subsequent manipulation, in which the probability of uncertain food varied within each session as a function of the previous uncertain outcome, examined how the previous outcome and probability of uncertain food affected choice in a dynamic environment. Uncertain-choice behavior increased with the probability of uncertain food. The rats exhibited increased sensitivity to probability changes and a greater degree of win–stay/lose–shift behavior than in the static phase. Simulations of two sequential choice models were performed to explore the possible mechanisms of reward value computations. The simulation results supported an exponentially decaying value function that updated as a function of trial (rather than time). These results emphasize the importance of analyzing global and local factors in choice behavior and suggest avenues for the future development of sequential-choice models. PMID:23205915

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.

Optimized phase gradient measurements and phase-amplitude interplay in optical coherence elastography

Science.gov (United States)

Zaitsev, Vladimir Y.; Matveyev, Alexander L.; Matveev, Lev A.; Gelikonov, Grigory V.; Sovetsky, Aleksandr A.; Vitkin, Alex

2016-11-01

In compressional optical coherence elastography, phase-variation gradients are used for estimating quasistatic strains created in tissue. Using reference and deformed optical coherence tomography (OCT) scans, one typically compares phases from pixels with the same coordinates in both scans. Usually, this limits the allowable strains to fairly small values advantages of the proposed optimized phase-variation methodology.

Improving image quality of parallel phase-shifting digital holography

International Nuclear Information System (INIS)

Awatsuji, Yasuhiro; Tahara, Tatsuki; Kaneko, Atsushi; Koyama, Takamasa; Nishio, Kenzo; Ura, Shogo; Kubota, Toshihiro; Matoba, Osamu

2008-01-01

The authors propose parallel two-step phase-shifting digital holography to improve the image quality of parallel phase-shifting digital holography. The proposed technique can increase the effective number of pixels of hologram twice in comparison to the conventional parallel four-step technique. The increase of the number of pixels makes it possible to improve the image quality of the reconstructed image of the parallel phase-shifting digital holography. Numerical simulation and preliminary experiment of the proposed technique were conducted and the effectiveness of the technique was confirmed. The proposed technique is more practical than the conventional parallel phase-shifting digital holography, because the composition of the digital holographic system based on the proposed technique is simpler.

A mass-conserving lattice Boltzmann method with dynamic grid refinement for immiscible two-phase flows

Energy Technology Data Exchange (ETDEWEB)

Fakhari, Abbas, E-mail: afakhari@nd.edu [Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556 (United States); Geier, Martin [TU Braunschweig, Institute for Computational Modeling in Civil Engineering (iRMB), TU-Braunschweig, Pockelsstr. 3, 38106 Braunschweig (Germany); Lee, Taehun [Department of Mechanical Engineering, The City College of the City University of New York, New York, NY 10031 (United States)

2016-06-15

A mass-conserving lattice Boltzmann method (LBM) for multiphase flows is presented in this paper. The proposed LBM improves a previous model (Lee and Liu, 2010 [21]) in terms of mass conservation, speed-up, and efficiency, and also extends its capabilities for implementation on non-uniform grids. The presented model consists of a phase-field lattice Boltzmann equation (LBE) for tracking the interface between different fluids and a pressure-evolution LBM for recovering the hydrodynamic properties. In addition to the mass conservation property and the simplicity of the algorithm, the advantages of the current phase-field LBE are that it is an order of magnitude faster than the previous interface tracking LBE proposed by Lee and Liu (2010) [21] and it requires less memory resources for data storage. Meanwhile, the pressure-evolution LBM is equipped with a multi-relaxation-time (MRT) collision operator to facilitate attainability of small relaxation rates thereby allowing simulation of multiphase flows at higher Reynolds numbers. Additionally, we reformulate the presented MRT-LBM on nonuniform grids within an adaptive mesh refinement (AMR) framework. Various benchmark studies such as a rising bubble and a falling drop under buoyancy, droplet splashing on a wet surface, and droplet coalescence onto a fluid interface are conducted to examine the accuracy and versatility of the proposed AMR-LBM. The proposed model is further validated by comparing the results with other LB models on uniform grids. A factor of about 20 in savings of computational resources is achieved by using the proposed AMR-LBM. As a more demanding application, the Kelvin–Helmholtz instability (KHI) of a shear-layer flow is investigated for both density-matched and density-stratified binary fluids. The KHI results of the density-matched fluids are shown to be in good agreement with the benchmark AMR results based on the sharp-interface approach. When a density contrast between the two fluids exists, a

A mass-conserving lattice Boltzmann method with dynamic grid refinement for immiscible two-phase flows

International Nuclear Information System (INIS)

Fakhari, Abbas; Geier, Martin; Lee, Taehun

2016-01-01

A mass-conserving lattice Boltzmann method (LBM) for multiphase flows is presented in this paper. The proposed LBM improves a previous model (Lee and Liu, 2010 [21]) in terms of mass conservation, speed-up, and efficiency, and also extends its capabilities for implementation on non-uniform grids. The presented model consists of a phase-field lattice Boltzmann equation (LBE) for tracking the interface between different fluids and a pressure-evolution LBM for recovering the hydrodynamic properties. In addition to the mass conservation property and the simplicity of the algorithm, the advantages of the current phase-field LBE are that it is an order of magnitude faster than the previous interface tracking LBE proposed by Lee and Liu (2010) [21] and it requires less memory resources for data storage. Meanwhile, the pressure-evolution LBM is equipped with a multi-relaxation-time (MRT) collision operator to facilitate attainability of small relaxation rates thereby allowing simulation of multiphase flows at higher Reynolds numbers. Additionally, we reformulate the presented MRT-LBM on nonuniform grids within an adaptive mesh refinement (AMR) framework. Various benchmark studies such as a rising bubble and a falling drop under buoyancy, droplet splashing on a wet surface, and droplet coalescence onto a fluid interface are conducted to examine the accuracy and versatility of the proposed AMR-LBM. The proposed model is further validated by comparing the results with other LB models on uniform grids. A factor of about 20 in savings of computational resources is achieved by using the proposed AMR-LBM. As a more demanding application, the Kelvin–Helmholtz instability (KHI) of a shear-layer flow is investigated for both density-matched and density-stratified binary fluids. The KHI results of the density-matched fluids are shown to be in good agreement with the benchmark AMR results based on the sharp-interface approach. When a density contrast between the two fluids exists, a

Solid-phase data from cores at the proposed Dewey Burdock uranium in-situ recovery mine, near Edgemont, South Dakota

Science.gov (United States)

Johnson, Raymond H.; Diehl, Sharon F.; Benzel, William M.

2013-01-01

This report releases solid-phase data from cores at the proposed Dewey Burdock uranium in-situ recovery site near Edgemont, South Dakota. These cores were collected by Powertech Uranium Corporation, and material not used for their analyses were given to the U.S. Geological Survey for additional sampling and analyses. These additional analyses included total carbon and sulfur, whole rock acid digestion for major and trace elements, 234U/238U activity ratios, X-ray diffraction, thin sections, scanning electron microscopy analyses, and cathodoluminescence. This report provides the methods and data results from these analyses along with a short summary of observations.

Determination of the full polarimetric transition matrix of a magnetized plasma from measurements of phase only

International Nuclear Information System (INIS)

Segre, S.E.

1996-09-01

It is shown that, by using a convenient modulated input polarization, it is possible to determine the full plasma polarimetric transition matrix purely from phase measurements. These are advantageous compared to previously proposed amplitude measurements. Two alternative sets of configurations for the input polarization are considered. The elements of the transition matrix thus found can be used in the reconstruction of the MHD equilibrium

A Dynamic and Heuristic Phase Balancing Method for LV Feeders

Directory of Open Access Journals (Sweden)

Samad Taghipour Boroujeni

2016-01-01

Full Text Available Due to the single-phase loads and their stochastic behavior, the current in the distribution feeders is not balanced. In addition, the single-phase loads are located in different positions along the LV feeders. So the amount of the unbalanced load and its location affect the feeder losses. An unbalanced load causes the feeder losses and the voltage drop. Because of time-varying behavior of the single-phase loads, phase balancing is a dynamic and combinatorial problem. In this research, a heuristic and dynamic solution for the phase balancing of the LV feeders is proposed. In this method, it is supposed that the loads’ tie could be connected to all phases through a three-phase switch. The aim of the proposed method is to make the feeder conditions as balanced as possible. The amount and the location of single-phase loads are considered in the proposed phase balancing method. Since the proposed method needs no communication interface or no remote controller, it is inexpensive, simple, practical, and robust. Applying this method provides a distributed and dynamic phase balancing control. In addition, the feasibility of reducing the used switches is investigated. The ability of the proposed method in the phase balancing of the LV feeders is approved by carrying out some simulations.

Phase II study of a 3-day schedule with topotecan and cisplatin in patients with previously untreated small cell lung cancer and extensive disease

DEFF Research Database (Denmark)

Sorensen, M.; Lassen, Ulrik Niels; Jensen, Peter Buhl

2008-01-01

INTRODUCTION: Treatment with a topoisomerase I inhibitor in combination with a platinum results in superior or equal survival compared with etoposide-based treatment in extensive disease small cell lung cancer (SCLC). Five-day topotecan is inconvenient and therefore shorter schedules of topotecan...... and cisplatin are needed. The aim of this phase II study was to establish the response rate and response duration in chemo-naive patients with SCLC receiving a 3-day topotecan and cisplatin schedule. METHODS: Simons optimal two-stage design was used. Patients with previously untreated extensive disease SCLC...... age was 59 (range 44-74), 79% had performance status 0 or 1. Thirty-one patients completed all six cycles. Grade 3/4 anemia, neutrocytopenia, and thrombocytopenia were recorded in 9.5%, 66.7%, and 21.4% of patients, respectively. Fourteen percent of patients experienced neutropenic fever. No episodes...

Aerospace Systems Monitor, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Proposal Title: Aerospace Systems Monitor PHASE 1 Technical Abstract: This Phase II STTR project will continue development and commercialization of the Aerospace...

Tilt shift determinations with spatial-carrier phase-shift method in temporal phase-shift interferometry

International Nuclear Information System (INIS)

Liu, Qian; Wang, Yang; He, Jianguo; Ji, Fang; Wang, Baorui

2014-01-01

An algorithm is proposed to deal with tilt-shift errors in temporal phase-shift interferometry (PSI). In the algorithm, the tilt shifts are detected with the spatial-carrier phase-shift (SCPS) method and then the tilt shifts are applied as priori information to the least-squares fittings of phase retrieval. The algorithm combines the best features of the SCPS and the temporal PSI. The algorithm could be applied to interferograms of arbitrary aperture without data extrapolation for the Fourier transform is not involved. Simulations and experiments demonstrate the effectiveness of the algorithm. The statistics of simulation results show a satisfied accuracy in detecting tilt-shift errors. Comparisons of the measurements with and without environmental vibration show that the proposed algorithm could compensate tilt-shift errors and retrieve wavefront phase accurately. The algorithm provides an approach to retrieve wavefront phase for the temporal PSI in vibrating environment. (paper)

Proposed Terminology and Classification of Pre-Malignant Neoplastic Conditions: A Consensus Proposal

Directory of Open Access Journals (Sweden)

Peter Valent

2017-12-01

Full Text Available Cancer evolution is a step-wise non-linear process that may start early in life or later in adulthood, and includes pre-malignant (indolent and malignant phases. Early somatic changes may not be detectable or are found by chance in apparently healthy individuals. The same lesions may be detected in pre-malignant clonal conditions. In some patients, these lesions may never become relevant clinically whereas in others, they act together with additional pro-oncogenic hits and thereby contribute to the formation of an overt malignancy. Although some pre-malignant stages of a malignancy have been characterized, no global system to define and to classify these conditions is available. To discuss open issues related to pre-malignant phases of neoplastic disorders, a working conference was organized in Vienna in August 2015. The outcomes of this conference are summarized herein and include a basic proposal for a nomenclature and classification of pre-malignant conditions. This proposal should assist in the communication among patients, physicians and scientists, which is critical as genome-sequencing will soon be offered widely for early cancer-detection.

A cascaded three-phase symmetrical multistage voltage multiplier

International Nuclear Information System (INIS)

Iqbal, Shahid; Singh, G K; Besar, R; Muhammad, G

2006-01-01

A cascaded three-phase symmetrical multistage Cockcroft-Walton voltage multiplier (CW-VM) is proposed in this report. It consists of three single-phase symmetrical voltage multipliers, which are connected in series at their smoothing columns like string of batteries and are driven by three-phase ac power source. The smoothing column of each voltage multiplier is charged twice every cycle independently by respective oscillating columns and discharged in series through load. The charging discharging process completes six times a cycle and therefore the output voltage ripple's frequency is of sixth order of the drive signal frequency. Thus the proposed approach eliminates the first five harmonic components of load generated voltage ripples and sixth harmonic is the major ripple component. The proposed cascaded three-phase symmetrical voltage multiplier has less than half the voltage ripple, and three times larger output voltage and output power than the conventional single-phase symmetrical CW-VM. Experimental and simulation results of the laboratory prototype are given to show the feasibility of proposed cascaded three-phase symmetrical CW-VM

Stereoelectronic model to explain the resolution of enantiomeric ibuprofen amides on the Pirkle chiral stationary phase.

Science.gov (United States)

Nicoll-Griffith, D A

1987-07-31

A chiral recognition model is proposed which incorporates the electronic and steric interactions between amide derivatives of ibuprofen and the (R)-N-(3,5-dinitrobenzoyl)phenylglycine-derived Pirkle chiral stationary phase during high-performance liquid chromatography. Based on this rationale, amide derivatives of ibuprofen were prepared using 4-chloroaniline, 4-bromoaniline, aniline, 4-methoxyaniline and 1-aminonaphthylene to improve the enantiomer separation over previously reported results with this column. The amides prepared gave separation values of 1.16, 1.16, 1.19, 1.21 and 1.23, respectively. These high separation values are consistent with the proposed model.

Flexible, Phase Change Fabric for Deployable Decelerators, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — SDMA proposes to develop a flexible fabric containing Phase Change Materials that is suitable for use on Deployable Decelerators. This technology will make...

Free-piston reciprocating cryogenic expander utilizing phase controller

Science.gov (United States)

Cha, Jeongmin; Park, Jiho; Kim, Kyungjoong; Jeong, Sangkwon

2017-02-01

In a free-piston expander which eliminates mechanical linkages, a prescribed behaviour of the free-piston movement is the key to an expander performance. In this paper, we have proposed an idea of reducing complexity of the free-piston expander. It is to replace both multiple solenoid valves and reservoirs that are indispensable in a previous machine with a combination of a single orifice-reservoir assembly. It functions as a phase controller like that of a pulse tube refrigerator so that it generates time-delay of pressure variation between the warm-end and the reservoir resulting in the intended expansion of the cold-end volume down to the pre-set reservoir pressure. The modeling of this unique free-piston reciprocating expander utilizing phase controller is developed to understand and predict the performance of the new-type expander. Additionally, the operating parameters are analysed at the specified conditions to enable one to develop a more efficient free-piston type cryogenic expander.

An Efficient and Packing-Resilient Two-Phase Android Cloned Application Detection Approach

Directory of Open Access Journals (Sweden)

Fang Lyu

2017-01-01

Full Text Available The huge benefit of mobile application industry has attracted a large number of developers and attendant attackers. Application repackaging provides help for the distribution of most Android malware. It is a serious threat to the entire Android ecosystem, as it not only compromises the security and privacy of the app users but also plunders app developers’ income. Although massive approaches have been proposed to address this issue, plagiarists try to fight back through packing their malicious code with the help of commercial packers. Previous works either do not consider the packing issue or rely on time-consuming computations, which are not scalable for large-scale real-world scenario. In this paper, we propose FUIDroid, a novel two-phase app clones detection system that can detect the packed cloned app. FUIDroid includes a function-based fast selection phase to quickly select suspicious apps by analyzing apps’ description and a further UI-based accurate detection phase to refine the detection result. We evaluate our system on two sets of apps. The result from experiment on 320 packed samples demonstrates that FUIDroid is resilient to packed apps. The evaluation on more than 150,000 real-world apps shows the efficiency of FUIDroid in large-scale scenario.

Concurrent Chemoradiotherapy Followed by Consolidation Chemotherapy With Bi-Weekly Docetaxel and Carboplatin for Stage III Unresectable, Non-Small-Cell Lung Cancer: Clinical Application of a Protocol Used in a Previous Phase II Study

International Nuclear Information System (INIS)

Saitoh, Jun-Ichi; Saito, Yoshihiro; Kazumoto, Tomoko; Kudo, Shigehiro; Yoshida, Daisaku; Ichikawa, Akihiro; Sakai, Hiroshi; Kurimoto, Futoshi; Kato, Shingo; Shibuya, Kei

2012-01-01

Purpose: To assess the clinical applicability of a protocol evaluated in a previously reported phase II study of concurrent chemoradiotherapy followed by consolidation chemotherapy with bi-weekly docetaxel and carboplatin in patients with stage III, unresectable, non-small-cell lung cancer (NSCLC). Methods and Materials: Between January 2000 and March 2006, 116 previously untreated patients with histologically proven, stage III NSCLC were treated with concurrent chemoradiotherapy. Radiation therapy was administered in 2-Gy daily fractions to a total dose of 60 Gy in combination with docetaxel, 30 mg/m 2 , and carboplatin at an area under the curve value of 3 every 2 weeks during and after radiation therapy. Results: The median survival time for the entire group was 25.5 months. The actuarial 2-year and 5-year overall survival rates were 53% and 31%, respectively. The 3-year cause-specific survival rate was 60% in patients with stage IIIA disease, whereas it was 35% in patients with stage IIIB disease (p = 0.007). The actuarial 2-year and 5-year local control rates were 62% and 55%, respectively. Acute hematologic toxicities of Grade ≥3 severity were observed in 20.7% of patients, while radiation pneumonitis and esophagitis of Grade ≥3 severity were observed in 2.6% and 1.7% of patients, respectively. Conclusions: The feasibility of the protocol used in the previous phase II study was reconfirmed in this series, and excellent treatment results were achieved.

Concurrent Chemoradiotherapy Followed by Consolidation Chemotherapy With Bi-Weekly Docetaxel and Carboplatin for Stage III Unresectable, Non-Small-Cell Lung Cancer: Clinical Application of a Protocol Used in a Previous Phase II Study

Energy Technology Data Exchange (ETDEWEB)

Saitoh, Jun-Ichi, E-mail: junsaito@sannet.ne.jp [Division of Radiation Oncology, Saitama Cancer Center, Saitama (Japan); Saito, Yoshihiro; Kazumoto, Tomoko; Kudo, Shigehiro; Yoshida, Daisaku; Ichikawa, Akihiro [Division of Radiation Oncology, Saitama Cancer Center, Saitama (Japan); Sakai, Hiroshi; Kurimoto, Futoshi [Division of Respiratory Disease, Saitama Cancer Center, Saitama (Japan); Kato, Shingo [Research Center Hospital for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan); Shibuya, Kei [Department of Radiation Oncology, Gunma University Graduate School of Medicine, Gunma (Japan)

2012-04-01

Purpose: To assess the clinical applicability of a protocol evaluated in a previously reported phase II study of concurrent chemoradiotherapy followed by consolidation chemotherapy with bi-weekly docetaxel and carboplatin in patients with stage III, unresectable, non-small-cell lung cancer (NSCLC). Methods and Materials: Between January 2000 and March 2006, 116 previously untreated patients with histologically proven, stage III NSCLC were treated with concurrent chemoradiotherapy. Radiation therapy was administered in 2-Gy daily fractions to a total dose of 60 Gy in combination with docetaxel, 30 mg/m{sup 2}, and carboplatin at an area under the curve value of 3 every 2 weeks during and after radiation therapy. Results: The median survival time for the entire group was 25.5 months. The actuarial 2-year and 5-year overall survival rates were 53% and 31%, respectively. The 3-year cause-specific survival rate was 60% in patients with stage IIIA disease, whereas it was 35% in patients with stage IIIB disease (p = 0.007). The actuarial 2-year and 5-year local control rates were 62% and 55%, respectively. Acute hematologic toxicities of Grade {>=}3 severity were observed in 20.7% of patients, while radiation pneumonitis and esophagitis of Grade {>=}3 severity were observed in 2.6% and 1.7% of patients, respectively. Conclusions: The feasibility of the protocol used in the previous phase II study was reconfirmed in this series, and excellent treatment results were achieved.

Determination of complex formation constants by phase sensitive alternating current polarography: Cadmium-polymethacrylic acid and cadmium-polygalacturonic acid.

Science.gov (United States)

Garrigosa, Anna Maria; Gusmão, Rui; Ariño, Cristina; Díaz-Cruz, José Manuel; Esteban, Miquel

2007-10-15

The use of phase sensitive alternating current polarography (ACP) for the evaluation of complex formation constants of systems where electrodic adsorption is present has been proposed. The applicability of the technique implies the previous selection of the phase angle where contribution of capacitive current is minimized. This is made using Multivariate Curve Resolution by Alternating Least Squares (MCR-ALS) in the analysis of ACP measurements at different phase angles. The method is checked by the study of the complexation of Cd by polymethacrylic (PMA) and polygalacturonic (PGA) acids, and the optimal phase angles have been ca. -10 degrees for Cd-PMA and ca. -15 degrees for Cd-PGA systems. The goodness of phase sensitive ACP has been demonstrated comparing the determined complex formation constants with those obtained by reverse pulse polarography, a technique that minimizes the electrode adsorption effects on the measured currents.

Optical trapping via guided resonance modes in a Slot-Suzuki-phase photonic crystal lattice.

Science.gov (United States)

Ma, Jing; Martínez, Luis Javier; Povinelli, Michelle L

2012-03-12

A novel photonic crystal lattice is proposed for trapping a two-dimensional array of particles. The lattice is created by introducing a rectangular slot in each unit cell of the Suzuki-Phase lattice to enhance the light confinement of guided resonance modes. Large quality factors on the order of 10⁵ are predicted in the lattice. A significant decrease of the optical power required for optical trapping can be achieved compared to our previous design.

APT, The Phase I tool for HST Cycle 12

Science.gov (United States)

Blacker, Brett S.; Bertch, Maria; Curtis, Gary; Douglas, Robert E., Jr.; Krueger, Anthony P.

2002-12-01

In the continuing effort to streamline our systems and improve service to the science community, the Space Telescope Science Institute (STScI) is developing and releasing, APT The Astronomer’s Proposal Tool as the new interface for Hubble Space Telescope (HST) Phase I and Phase II proposal submissions for HST Cycle 12. APT, was formerly called the Scientist’s Expert Assistant (SEA), which started as a prototype effort to try and bring state of the art technology, more visual tools and power into the hands of proposers so that they can optimize the scientific return of their programs as well as HST. Proposing for HST and other missions, consists of requesting observing time and/or archival research funding. This step is called Phase I, where the scientific merit of a proposal is considered by a community based peer-review process. Accepted proposals then proceed thru Phase II, where the observations are specified in sufficient detail to enable scheduling on the telescope. In this paper, we will present our concept and implementation plans for our Phase I development and submission tool, APT. More importantly, we will go behind the scenes and discuss why it’s important for the Science Policies Division (SPD) and other groups at the STScI to have a new submission tool and submission output products. This paper is an update of the status of the HST Phase I Proposal Processing System that was described in the published paper “A New Era for HST Phase I Development and Submission.”

Does quasi-long-range order in the two-dimensional XY model really survive weak random phase fluctuations?

International Nuclear Information System (INIS)

Mudry, Christopher; Wen Xiaogang

1999-01-01

Effective theories for random critical points are usually non-unitary, and thus may contain relevant operators with negative scaling dimensions. To study the consequences of the existence of negative-dimensional operators, we consider the random-bond XY model. It has been argued that the XY model on a square lattice, when weakly perturbed by random phases, has a quasi-long-range ordered phase (the random spin wave phase) at sufficiently low temperatures. We show that infinitely many relevant perturbations to the proposed critical action for the random spin wave phase were omitted in all previous treatments. The physical origin of these perturbations is intimately related to the existence of broadly distributed correlation functions. We find that those relevant perturbations do enter the Renormalization Group equations, and affect critical behavior. This raises the possibility that the random XY model has no quasi-long-range ordered phase and no Kosterlitz-Thouless (KT) phase transition

Quantum phases, supersolids and quantum phase transitions of interacting bosons in frustrated lattices

International Nuclear Information System (INIS)

Ye, Jinwu; Chen, Yan

2013-01-01

By using the dual vortex method (DVM), we develop systematically a simple and effective scheme to use the vortex degree of freedoms on dual lattices to characterize the symmetry breaking patterns of the boson insulating states in the direct lattices. Then we apply our scheme to study quantum phases and phase transitions in an extended boson Hubbard model slightly away from 1/3 (2/3) filling on frustrated lattices such as triangular and Kagome lattice. In a triangular lattice at 1/3, we find a X-CDW, a stripe CDW phase which was found previously by a density operator formalism (DOF). Most importantly, we also find a new CDW-VB phase which has both local CDW and local VB orders, in sharp contrast to a bubble CDW phase found previously by the DOF. In the Kagome lattice at 1/3, we find a VBS phase and a 6-fold CDW phase. Most importantly, we also identify a CDW-VB phase which has both local CDW and local VB orders which was found in previous QMC simulations. We also study several other phases which are not found by the DVM. By analyzing carefully the saddle point structures of the dual gauge fields in the translational symmetry breaking sides and pushing the effective actions slightly away from the commensurate filling f=1/3(2/3), we classified all the possible types of supersolids and analyze their stability conditions. In a triangular lattice, there are X-CDW supersolid, stripe CDW supersolid, but absence of any valence bond supersolid (VB-SS). There are also a new kind of supersolid: CDW-VB supersolid. In a Kagome lattice, there are 6-fold CDW supersolid, stripe CDW supersolid, but absence of any valence bond supersolid (VB-SS). There are also a new kind of supersolid: CDW-VB supersolid. We show that independent of the types of the SS, the quantum phase transitions from solids to supersolids driven by a chemical potential are in the same universality class as that from a Mott insulator to a superfluid, therefore have exact exponents z=2, ν=1/2, η=0 (with

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.

A New Built-in Self Test Scheme for Phase-Locked Loops Using Internal Digital Signals

Science.gov (United States)

Kim, Youbean; Kim, Kicheol; Kim, Incheol; Kang, Sungho

Testing PLLs (phase-locked loops) is becoming an important issue that affects both time-to-market and production cost of electronic systems. Though a PLL is the most common mixed-signal building block, it is very difficult to test due to internal analog blocks and signals. In this paper, we propose a new PLL BIST (built-in self test) using the distorted frequency detector that uses only internal digital signals. The proposed BIST does not need to load any analog nodes of the PLL. Therefore, it provides an efficient defect-oriented structural test scheme, reduced area overhead, and improved test quality compared with previous approaches.

Thermodynamics of phase formation and heavy quasiparticles in Sr{sub 3}Ru{sub 2}O{sub 7}

Energy Technology Data Exchange (ETDEWEB)

Rost, Andreas W.; Bruin, Jan A.N.; Tian, Demian; Mackenzie, Andrew P. [SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY169SS (United Kingdom); Grigera, Santiago A. [SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY169SS (United Kingdom); Instituto de Fisica de Liquidos y Sistemas Biologicos, UNLP-CONICET, La Plata 1900 (Argentina); Perry, Robin S. [SUPA, School of Physics, University of Edinburgh, Mayfield Road, Edinburgh EH93JZ (United Kingdom); Raghu, Sri [Department of Physics and Astronomy, Rice University, Houston, Texas, 77005 (United States); Kivelson, Steve A. [Department of Physics, Stanford University, Stanford, California, 94305 (United States)

2012-07-01

The itinerant metamagnet Sr{sub 3}Ru{sub 2}O{sub 7} has motivated a wide range of experimental and theoretical work in recent years because of the discovery of an unusual low temperature phase which is forming in the vicinity of a proposed quantum critical point. A major challenge is the investigation of the thermodynamic properties of both this unusual phase and the fluctuations associated with the quantum critical point. Here we report on new specific heat measurements extending previous work to the wider phase diagram. Our results shed light on two important aspects of the system. First we discuss the entropic details of the formation of heavy quasiparticles as a function of temperature in this compound relevant for a wide class of materials. Secondly we present thermodynamic evidence for the anomalous low temperature phase forming directly out of the critical high temperature phase.

Proposal for a study of laser acceleration of electrons using micrograting structures at ATF (Phase 1)

International Nuclear Information System (INIS)

Chen, W.; Claus, J.; Fernow, R.C.

1989-01-01

We propose to investigate new methods of particle acceleration using a short-pulse CO 2 laser as the power source and grating-like structures as accelerator ''cavities''. Phase I of this program is intended to demonstrate the principle of the method. We will focus the laser light to a 3 mm line on the surface of the microstructure. The structure is used to transform the electric field pattern of the incoming transversely polarized laser beam to a mode which has a component along the electron beam direction in the vicinity of the surface. With 6 mJ of laser energy and a 6 ps pulse length, the electric field in the spot will be around 1 GV/m. The electron beam from the Brookhaven Accelerator Test Facility (ATF) will be focused transversely within the few micron transverse dimension of the microstructure. The maximum expected acceleration for a 1 GV/m field and a 3 mm acceleration length is 3 MeV. 17 refs., 11 figs., 2 tabs

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

Experimental study of low-titre critical two-phase flows

International Nuclear Information System (INIS)

Seynhaeve, Jean-Marie

1980-02-01

This report for engineering graduation addresses the analysis of two-phase critical flows obtained by expansion of a saturated or under-cooled liquid. For a titre greater than 0,1, theoretical studies give a rather good prediction of critical flow rates, whereas in the case of a lower titre, results obtained by published studies display some discrepancies, and the test duct geometry and important unbalances between phases seem to be at the origin of these discrepancies. In order to study these origins of discrepancies, three test campaigns have been performed: on a test duct provided by the CENG, on two long tubes, and on holes. Thus, after a bibliographical study which outlines drawbacks of previous studies, the author proposes a detailed description of experimental installations (creation of critical flows, measurement chain, measurement processing, measurement device calibration, quality and precision). Experimental results are then systematically explored, and differences are explained. The author then addresses the theoretical aspect of the determination of critical flow rates by reviewing calculation models and by comparing their results with experimental results. The validity of each model is thus discussed. The author then proposes a calculation model which can be applied to critical flows developed in holes. This model is notably inspired by experimental conclusions and gives very satisfying practical results

Direct imaging of phase objects enables conventional deconvolution in bright field light microscopy.

Directory of Open Access Journals (Sweden)

Carmen Noemí Hernández Candia

Full Text Available In transmitted optical microscopy, absorption structure and phase structure of the specimen determine the three-dimensional intensity distribution of the image. The elementary impulse responses of the bright field microscope therefore consist of separate absorptive and phase components, precluding general application of linear, conventional deconvolution processing methods to improve image contrast and resolution. However, conventional deconvolution can be applied in the case of pure phase (or pure absorptive objects if the corresponding phase (or absorptive impulse responses of the microscope are known. In this work, we present direct measurements of the phase point- and line-spread functions of a high-aperture microscope operating in transmitted bright field. Polystyrene nanoparticles and microtubules (biological polymer filaments serve as the pure phase point and line objects, respectively, that are imaged with high contrast and low noise using standard microscopy plus digital image processing. Our experimental results agree with a proposed model for the response functions, and confirm previous theoretical predictions. Finally, we use the measured phase point-spread function to apply conventional deconvolution on the bright field images of living, unstained bacteria, resulting in improved definition of cell boundaries and sub-cellular features. These developments demonstrate practical application of standard restoration methods to improve imaging of phase objects such as cells in transmitted light microscopy.

Phase separation over an extended compositional range: Studies of the Ca1-xBixMnO3 (x≤0.25) phase diagram

International Nuclear Information System (INIS)

Santhosh, P. N.; Goldberger, J.; Woodward, P. M.; Vogt, T.; Lee, W. P.; Epstein, A. J.

2000-01-01

Phase transitions on the electron-doped side of the Ca 1-x Bi x MnO 3 system (x≤0.25) have been investigated using high-resolution synchrotron x-ray and neutron powder-diffraction techniques, electrical transport and magnetic susceptibility measurements. At room temperature all samples investigated were single phase, paramagnetic conductors (ρ 3 (space group Pnma). The Mn-O-Mn angles remain nearly constant from x=0 to x=0.25, while the Mn-O distances steadily increase with the Mn 3+ content. Three distinct phases are observed at 25 K. The first one, observed from 0.15≥x≥0.03, is characterized by the absence of charge and orbital ordering, a canted G-type antiferromagnetic spin structure, and delocalized electron transport. The second phase, observed from 0.25≥x≥0.12 (single phase at x=0.18), is characterized by pronounced orbital ordering, a C-type antiferromagnetic spin structure, and insulating behavior. The third low-temperature phase, observed for x≥0.20, is characterized by orbital and magnetic ordering similar to the Wigner crystal structure previously observed for Ca 0.67 La 0.33 MnO 3 , but with a 4axbx2c unit cell. The most striking feature of the phase diagram is the wide compositional range over which low-temperature phase separation is observed. Only those samples with x<0.12 and x=0.18 did not undergo phase separation upon cooling. We show that this behavior cannot be attributed to compositional variations, and therefore, propose that anisotropic strain interactions between crystallites may be partially responsible for this behavior

MEMS based monolithic Phased array using 3-bit Switched-line Phase Shifter

Directory of Open Access Journals (Sweden)

A. Karmakr

2017-10-01

Full Text Available This article details the design of an electronically scanning phased array antenna with proposed fabrication process steps. Structure is based upon RF micro-electromechanical system (MEMS technology. Capacitive type shunt switches have been implemented here to cater high frequency operation. The architecture, which is deigned at 30 GHz, consists of 3-bit (11.25º, 22.5º and 45º integrated Switched-line phase shifter and a linearly polarized microstrip patch antenna. Detailed design tricks of the Ka-band phase shifter is outlined here. The whole design is targeted for future monolithic integration. So, the substrate of choice is High Resistive Silicon (ρ > 8kΩ-cm, tan δ =0.01 and ϵr =11.8. The overall circuit occupies an cross-sectional area of 20 × 5 mm2. The simulated results show that the phase shifter can provide nearly 11.25º/22.5º/45º phase shifts and their combinations at the expense of 1dB average insertion loss at 30 GHz for eight combinations. Practical fabrication process flow using surface micromachining is proposed here. Critical dimensions of the phased array structure is governed by the deign rules of the standard CMOS/MEMS foundry.

Superconductivity in the Sr-Ca-Cu-O system and the phase with infinite-layer structure

International Nuclear Information System (INIS)

Shaked, H.; Shimakawa, Y.; Hunter, B.A.; Hitterman, R.L.; Jorgensen, J.D.; Han, P.D.; Payne, D.A.

1995-01-01

Superconductivity and structure in samples of (Sr,Ca)CuO 2 with the infinite-layer structure, prepared by high-pressure synthesis, have been studied using magnetic susceptibility measurements, small angle x-ray diffraction, and neutron diffraction. It is found that the superconducting (T c ∼100 K) samples in this system are phase impure and contain, in addition to the infinite-layer phase, members of the two homologous series Sr n-1 Cu n+1 O 2n (n=3,5,...; orthorhombic), and Sr n+1 Cu n O 2n+1+δ (n=1,2,...; tetragonal), as minor phases. Samples with larger phase fractions of the Sr n+1 Cu n O 2n+1+δ compounds showed higher superconducting fractions. Phase-pure infinite-layer samples are not superconducting. Based on these results, and results previously published in the literature, it is proposed that the superconductivity in these infinite-layer samples comes from the tetragonal Sr n+1 Cu n O 2n+1+δ compounds, not from the phase with the infinite-layer structure

Polarized differential-phase laser scanning microscope

International Nuclear Information System (INIS)

Chou Chien; Lyu, C.-W.; Peng, L.-C.

2001-01-01

A polarized differential-phase laser scanning microscope, which combines a polarized optical heterodyne Mach-Zehnder interferometer and a differential amplifier to scan the topographic image of a surface, is proposed. In the experiment the differential amplifier, which acts as a PM-AM converter, in the experiment, converting phase modulation (PM) into amplitude modulation (AM). Then a novel, to our knowledge, phase demodulator was proposed and implemented for the differential-phase laser scanning microscope. An optical grating (1800 lp/mm) was imaged. The lateral and the depth resolutions of the imaging system were 0.5 μm and 1 nm, respectively. The detection accuracy, which was limited by the reflectivity variation of the test surface, is discussed

NASA Research Announcement Phase 1 Report and Phase 2 Proposal for the Development of a Power Assisted Space Suit Glove Assembly

Science.gov (United States)

Cadogan, Dave; Lingo, Bob

1996-01-01

In July of 1996, ILC Dover was awarded Phase 1 of a contract for NASA to develop a prototype Power Assisted Space Suit glove to enhance the performance of astronauts during Extra-Vehicular Activity (EVA). This report summarizes the work performed to date on Phase 1, and details the work to be conducted on Phase 2 of the program. Phase 1 of the program consisted of research and review of related technical sources, concept brainstorming, baseline design development, modeling and analysis, component mock-up testing, and test data analysis. ILC worked in conjunction with the University of Maryland's Space Systems Laboratory (SSL) to develop the power assisted glove. Phase 2 activities will focus on the design maturation and the manufacture of a working prototype system. The prototype will be tested and evaluated in conjunction with existing space suit glove technology to determine the performance enhancement anticipated with the implementation of the power assisted joint technology in space suit gloves.

Experimental investigation of a two-phase closed thermosyphon assembly for passive containment cooling system

Energy Technology Data Exchange (ETDEWEB)

Nam, Kyung Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Sang Nyung [Kyunghee Univ., Gyeonggi-do (Korea, Republic of)

2017-06-15

After the Fukushima accident, increasing interest has been raised in passive safety systems that maintain the integrity of the containment building. To improve the reliability and safety of nuclear power plants, long-term passive cooling concepts have been developed for advanced reactors. In a previous study, the proposed design was based on an ordinary cylindrical Two-Phase Closed Thermosyphon (TPCT). The exact assembly size and number of TPCTs should be elaborated upon through accurate calculations based on experiments. While the ultimate goal is to propose an effective MPHP design for the PCCS and experimentally verify its performance, a TPCT assembly that was manufactured based on the conceptual design in this paper was tested.

A new approach to the analysis of the phase space of f(R)-gravity

Energy Technology Data Exchange (ETDEWEB)

Carloni, S., E-mail: sante.carloni@tecnico.ulisboa.pt [Centro Multidisciplinar de Astrofisica—CENTRA, Instituto Superior Tecnico – IST, Universidade de Lisboa – UL, Avenida Rovisco Pais 1, 1049-001 (Portugal)

2015-09-01

We propose a new dynamical system formalism for the analysis of f(R) cosmologies. The new approach eliminates the need for cumbersome inversions to close the dynamical system and allows the analysis of the phase space of f(R)-gravity models which cannot be investigated using the standard technique. Differently form previously proposed similar techniques, the new method is constructed in such a way to associate to the fixed points scale factors, which contain four integration constants (i.e. solutions of fourth order differential equations). In this way a new light is shed on the physical meaning of the fixed points. We apply this technique to some f(R) Lagrangians relevant for inflationary and dark energy models.

77 FR 5998 - Airworthiness Directives; EADS CASA (Type Certificate Previously Held by Construcciones...

Science.gov (United States)

2012-02-07

... Airworthiness Directives; EADS CASA (Type Certificate Previously Held by Construcciones Aeronauticas, S.A... proposed to correct an unsafe condition for the specified products. The MCAI states: EADS-CASA received... address this condition, EADS-CASA has developed an engine condition control cable P/N 35-56382-0005 with...

Fast conjugate phase image reconstruction based on a Chebyshev approximation to correct for B0 field inhomogeneity and concomitant gradients.

Science.gov (United States)

Chen, Weitian; Sica, Christopher T; Meyer, Craig H

2008-11-01

Off-resonance effects can cause image blurring in spiral scanning and various forms of image degradation in other MRI methods. Off-resonance effects can be caused by both B0 inhomogeneity and concomitant gradient fields. Previously developed off-resonance correction methods focus on the correction of a single source of off-resonance. This work introduces a computationally efficient method of correcting for B0 inhomogeneity and concomitant gradients simultaneously. The method is a fast alternative to conjugate phase reconstruction, with the off-resonance phase term approximated by Chebyshev polynomials. The proposed algorithm is well suited for semiautomatic off-resonance correction, which works well even with an inaccurate or low-resolution field map. The proposed algorithm is demonstrated using phantom and in vivo data sets acquired by spiral scanning. Semiautomatic off-resonance correction alone is shown to provide a moderate amount of correction for concomitant gradient field effects, in addition to B0 imhomogeneity effects. However, better correction is provided by the proposed combined method. The best results were produced using the semiautomatic version of the proposed combined method.

Microgravity Two-Phase Flow Transition

Science.gov (United States)

Parang, M.; Chao, D.

1999-01-01

Two-phase flows under microgravity condition find a large number of important applications in fluid handling and storage, and spacecraft thermal management. Specifically, under microgravity condition heat transfer between heat exchanger surfaces and fluids depend critically on the distribution and interaction between different fluid phases which are often qualitatively different from the gravity-based systems. Heat transfer and flow analysis in two-phase flows under these conditions require a clear understanding of the flow pattern transition and development of appropriate dimensionless scales for its modeling and prediction. The physics of this flow is however very complex and remains poorly understood. This has led to various inadequacies in flow and heat transfer modeling and has made prediction of flow transition difficult in engineering design of efficient thermal and flow systems. In the present study the available published data for flow transition under microgravity condition are considered for mapping. The transition from slug to annular flow and from bubbly to slug flow are mapped using dimensionless variable combination developed in a previous study by the authors. The result indicate that the new maps describe the flow transitions reasonably well over the range of the data available. The transition maps are examined and the results are discussed in relation to the presumed balance of forces and flow dynamics. It is suggested that further evaluation of the proposed flow and transition mapping will require a wider range of microgravity data expected to be made available in future studies.

Performance improvement of coherent free-space optical communication with quadrature phase-shift keying modulation using digital phase estimation.

Science.gov (United States)

Li, Xueliang; Geng, Tianwen; Ma, Shuang; Li, Yatian; Gao, Shijie; Wu, Zhiyong

2017-06-01

The performance of coherent free-space optical (CFSO) communication with phase modulation is limited by both phase fluctuations and intensity scintillations induced by atmospheric turbulence. To improve the system performance, one effective way is to use digital phase estimation. In this paper, a CFSO communication system with quadrature phase-shift keying modulation is studied. With consideration of the effects of log-normal amplitude fluctuations and Gauss phase fluctuations, a two-stage Mth power carrier phase estimation (CPE) scheme is proposed. The simulation results show that the phase noise can be suppressed greatly by this scheme, and the system symbol error rate performance with the two-stage Mth power CPE can be three orders lower than that of the single-stage Mth power CPE. Therefore, the two-stage CPE we proposed can contribute to the performance improvements of the CFSO communication system and has determinate guidance sense to its actual application.

Proposed equation of state experimental program at NOVA/NIF

International Nuclear Information System (INIS)

Holmes, N.C.; Cauble, R.; Celliers, P.; Collins, G.; DaSilva, L.; Hammel, B.; Stewart, R.; Strand, O.; Sullivan, A.

1996-03-01

The high pressure equations of state of materials must be accurately known for confident design, simulation, and interpretation of ICF target experiments and for weapons. Here, the authors sketch out a program to perform precise and accurate equation of state (EOS) experiments using large, high-power lasers. The program is divided into three phases: (1) a driver qualification program which will determine the necessary drive and target design parameters; (2) characterization of low and high-Z standard materials; (3) accurate impedance-match experiments to determine equations of state of materials of interest relative to the qualified standards. Novel methods are proposed for the first phase which are an order of magnitude more sensitive than those applied previously. They identify and describe the choices for standards and the samples slated for initial studies. In all cases, their goal is to obtain data that is of sufficiently high quality to serve for design purposes and to validate theories of material response at high pressures of the order of 1--10 TPa. This is particularly important right now, for materials such as CH plastics and hydrogen (DT). In addition, they will suggest a program for EOS measurements for P > 10 TPa, the region of maximum theoretical EOS uncertainty for many materials

Proposed Terminology and Classification of Pre-Malignant Neoplastic Conditions: A Consensus Proposal.

Science.gov (United States)

Valent, Peter; Akin, Cem; Arock, Michel; Bock, Christoph; George, Tracy I; Galli, Stephen J; Gotlib, Jason; Haferlach, Torsten; Hoermann, Gregor; Hermine, Olivier; Jäger, Ulrich; Kenner, Lukas; Kreipe, Hans; Majeti, Ravindra; Metcalfe, Dean D; Orfao, Alberto; Reiter, Andreas; Sperr, Wolfgang R; Staber, Philipp B; Sotlar, Karl; Schiffer, Charles; Superti-Furga, Giulio; Horny, Hans-Peter

2017-12-01

Cancer evolution is a step-wise non-linear process that may start early in life or later in adulthood, and includes pre-malignant (indolent) and malignant phases. Early somatic changes may not be detectable or are found by chance in apparently healthy individuals. The same lesions may be detected in pre-malignant clonal conditions. In some patients, these lesions may never become relevant clinically whereas in others, they act together with additional pro-oncogenic hits and thereby contribute to the formation of an overt malignancy. Although some pre-malignant stages of a malignancy have been characterized, no global system to define and to classify these conditions is available. To discuss open issues related to pre-malignant phases of neoplastic disorders, a working conference was organized in Vienna in August 2015. The outcomes of this conference are summarized herein and include a basic proposal for a nomenclature and classification of pre-malignant conditions. This proposal should assist in the communication among patients, physicians and scientists, which is critical as genome-sequencing will soon be offered widely for early cancer-detection. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Phase calibration approaches for radar interferometry and imaging configurations: equatorial spread F results

Directory of Open Access Journals (Sweden)

J. L. Chau

2008-08-01

Full Text Available In recent years, more and more radar systems with multiple-receiver antennas are being used to study the atmospheric and ionospheric irregularities with either interferometric and/or imaging configurations. In such systems, one of the major challenges is to know the phase offsets between the different receiver channels. Such phases are intrinsic to the system and are due to different cable lengths, filters, attenuators, amplifiers, antenna impedance, etc. Moreover, such phases change as function of time, on different time scales, depending on the specific installation. In this work, we present three approaches using natural targets (radio stars, meteor-head and meteor trail echoes that allow either an absolute or relative phase calibration. In addition, we present the results of using an artificial source (radio beacon for a continuous calibration that complements the previous approaches. These approaches are robust and good alternatives to other approaches, e.g. self-calibration techniques using known data features, or for multiple-receiver configurations constantly changing their receiving elements. In order to show the good performance of the proposed phase calibration techniques, we present new radar imaging results of equatorial spread F (ESF irregularities. Finally we introduce a new way to represent range-time intensity (RTI maps color coded with the Doppler information. Such modified map allows the identification and interpretation of geophysical phenomena, previously hidden in conventional RTI maps, e.g. the time and altitude of occurrence of ESF irregularities pinching off from the bottomside and their respective Doppler velocity.

Decomposition of Composite Electric Field in a Three-Phase D-Dot Voltage Transducer Measuring System

Directory of Open Access Journals (Sweden)

Xueqi Hu

2016-10-01

Full Text Available In line with the wider application of non-contact voltage transducers in the engineering field, transducers are required to have better performance for different measuring environments. In the present study, the D-dot voltage transducer is further improved based on previous research in order to meet the requirements for long-distance measurement of electric transmission lines. When measuring three-phase electric transmission lines, problems such as synchronous data collection and composite electric field need to be resolved. A decomposition method is proposed with respect to the superimposed electric field generated between neighboring phases. The charge simulation method is utilized to deduce the decomposition equation of the composite electric field and the validity of the proposed method is verified by simulation calculation software. With the deduced equation as the algorithm foundation, this paper improves hardware circuits, establishes a measuring system and constructs an experimental platform for examination. Under experimental conditions, a 10 kV electric transmission line was tested for steady-state errors, and the measuring results of the transducer and the high-voltage detection head were compared. Ansoft Maxwell Stimulation Software was adopted to obtain the electric field intensity in different positions under transmission lines; its values and the measuring values of the transducer were also compared. Experimental results show that the three-phase transducer is characterized by a relatively good synchronization for data measurement, measuring results with high precision, and an error ratio within a prescribed limit. Therefore, the proposed three-phase transducer can be broadly applied and popularized in the engineering field.

Dabrafenib plus trametinib in patients with previously untreated BRAFV600E-mutant metastatic non-small-cell lung cancer: an open-label, phase 2 trial.

Science.gov (United States)

Planchard, David; Smit, Egbert F; Groen, Harry J M; Mazieres, Julien; Besse, Benjamin; Helland, Åslaug; Giannone, Vanessa; D'Amelio, Anthony M; Zhang, Pingkuan; Mookerjee, Bijoyesh; Johnson, Bruce E

2017-10-01

BRAF V600E mutation occurs in 1-2% of lung adenocarcinomas and acts as an oncogenic driver. Dabrafenib, alone or combined with trametinib, has shown substantial antitumour activity in patients with previously treated BRAF V600E -mutant metastatic non-small-cell lung cancer (NSCLC). We aimed to assess the activity and safety of dabrafenib plus trametinib treatment in previously untreated patients with BRAF V600E -mutant metastatic NSCLC. In this phase 2, sequentially enrolled, multicohort, multicentre, non-randomised, open-label study, adults (≥18 years of age) with previously untreated metastatic BRAF V600E -mutant NSCLC were enrolled into cohort C from 19 centres in eight countries within North America, Europe, and Asia. Patients received oral dabrafenib 150 mg twice per day plus oral trametinib 2 mg once per day until disease progression, unacceptable adverse events, consent withdrawal, or death. The primary endpoint was investigator-assessed overall response, defined as the percentage of patients who achieved a confirmed complete response or partial response per Response Evaluation Criteria In Solid Tumors version 1.1. The primary and safety analyses were by intention to treat in the protocol-defined population (previously untreated patients). The study is ongoing, but no longer recruiting patients. This trial is registered with ClinicalTrials.gov, number NCT01336634. Between April 16, 2014, and Dec 28, 2015, 36 patients were enrolled and treated with first-line dabrafenib plus trametinib. Median follow-up was 15·9 months (IQR 7·8-22·0) at the data cutoff (April 28, 2017). The proportion of patients with investigator-assessed confirmed overall response was 23 (64%, 95% CI 46-79), with two (6%) patients achieving a complete response and 21 (58%) a partial response. All patients had one or more adverse event of any grade, and 25 (69%) had one or more grade 3 or 4 event. The most common (occurring in more than two patients) grade 3 or 4 adverse events were

Multi-phase alternative current machine winding design | Khan ...

African Journals Online (AJOL)

... single-phase to 18-phase excitation. Experimental results of a five-phase induction machine supplied from a static five-phase supply are provided to support the proposed design. Keywords: AC machine, Multi-phase machine, Stator winding, Five-phase. International Journal of Engineering, Science and Technology, Vol.

Analytical approximations to seawater optical phase functions of scattering

Science.gov (United States)

Haltrin, Vladimir I.

2004-11-01

This paper proposes a number of analytical approximations to the classic and recently measured seawater light scattering phase functions. The three types of analytical phase functions are derived: individual representations for 15 Petzold, 41 Mankovsky, and 91 Gulf of Mexico phase functions; collective fits to Petzold phase functions; and analytical representations that take into account dependencies between inherent optical properties of seawater. The proposed phase functions may be used for problems of radiative transfer, remote sensing, visibility and image propagation in natural waters of various turbidity.

The phase diagram of the Shastry-Sutherland antiferromagnet

International Nuclear Information System (INIS)

Zheng, W.; Oitmaa, J.; Hamer, C.J.

2002-01-01

Full text: The material SrCu 2 (BO 3 ) 2 , synthesised only a few years ago, appears to be an excellent realization of the Shastry-Sutherland model. The main physics of this model is a competition between Neel order and dimerization. Early studies suggested a single quantum phase transition separating these two phases, but recent studies suggest the presence of an intermediate phase. Various candidates for this intermediate phase have been proposed, including long-range helical order, and a plaquette-singlet phase. We use series expansion methods to argue against each of these, although our new extended results do support the existence of an intermediate phase of some kind. We propose a columnar dimer phase, as a possible candidate, and explore some of its properties

Isotropic differential phase contrast microscopy for quantitative phase bio-imaging.

Science.gov (United States)

Chen, Hsi-Hsun; Lin, Yu-Zi; Luo, Yuan

2018-05-16

Quantitative phase imaging (QPI) has been investigated to retrieve optical phase information of an object and applied to biological microscopy and related medical studies. In recent examples, differential phase contrast (DPC) microscopy can recover phase image of thin sample under multi-axis intensity measurements in wide-field scheme. Unlike conventional DPC, based on theoretical approach under partially coherent condition, we propose a new method to achieve isotropic differential phase contrast (iDPC) with high accuracy and stability for phase recovery in simple and high-speed fashion. The iDPC is simply implemented with a partially coherent microscopy and a programmable thin-film transistor (TFT) shield to digitally modulate structured illumination patterns for QPI. In this article, simulation results show consistency of our theoretical approach for iDPC under partial coherence. In addition, we further demonstrate experiments of quantitative phase images of a standard micro-lens array, as well as label-free live human cell samples. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The role of the incommensurate phase in the opalescence of quartz

Science.gov (United States)

Dolino, G.; Bastie, P.

2001-12-01

Forty five years ago, an intense light scattering was observed at the α-β transition of quartz but the origin of this opalescence has remained mysterious for a long time. Recently Saint-Grégoire et al and Aslanyan et al have explained the origin of the opalescence by introducing new incommensurate (`inc') phases with ferroelastic properties in the transition region. In this paper we recall the main features of the α-β transition, of the inc phase and of the opalescence of quartz, which presents different properties in two regions of the α-inc phase boundary. We also describe the three typical structures observed in the phase boundary regions by electron microscopy. We present briefly the two previous ferroelastic models and we propose our own explanation for the origin of the opalescence. We discuss the relations of these three models with experimental results concerning thermal behaviour, microscopic structures and the origin of the refractive index variations. Most experimental results are in agreement, at least qualitatively, with our model where the two opalescence regions correspond respectively to the presence of inc rotation patches and of irregular Dauphiné microtwins, both in a non-equilibrium state.

The role of the incommensurate phase in the opalescence of quartz

Energy Technology Data Exchange (ETDEWEB)

Dolino, G.; Bastie, P. [Laboratoire de Spectrometrie Physique, Universite J. Fourier (Grenoble I), CNRS UMR 5588, BP 87, Saint Martin d' Heres Cedex (France)]. E-mail: Dolino@spectro.ujf-grenoble.fr

2001-12-17

Forty five years ago, an intense light scattering was observed at the {alpha}-{beta} transition of quartz but the origin of this opalescence has remained mysterious for a long time. Recently Saint-Gregoire et al and Aslanyan et al have explained the origin of the opalescence by introducing new incommensurate ('inc') phases with ferroelastic properties in the transition region. In this paper we recall the main features of the {alpha}- {beta} transition, of the inc phase and of the opalescence of quartz, which presents different properties in two regions of the -inc phase boundary. We also describe the three typical structures observed in the phase boundary regions by electron microscopy. We present briefly the two previous ferroelastic models and we propose our own explanation for the origin of the opalescence. We discuss the relations of these three models with experimental results concerning thermal behaviour, microscopic structures and the origin of the refractive index variations. Most experimental results are in agreement, at least qualitatively, with our model where the two opalescence regions correspond respectively to the presence of inc rotation patches and of irregular Dauphine microtwins, both in a non-equilibrium state. (author)

Synthesis and characterization of mixed phases in the Ca–Co–O system using the Pechini method

Energy Technology Data Exchange (ETDEWEB)

Tran, Hoa; Mehta, Tejas [College of DuPage, 425 Fawell Blvd, Glen Ellyn, IL 60137-6599 (United States); Zeller, Matthias [Department of Chemistry, Youngstown State University, 1 University Plaza, Youngstown, OH 44555-3663 (United States); Jarman, Richard H., E-mail: Jarman@cod.edu [College of DuPage, 425 Fawell Blvd, Glen Ellyn, IL 60137-6599 (United States)

2013-07-15

Highlights: ► We have prepared mixed Ca–Co–O phases using the Pechini method. ► Reaction times are reduced relative to conventional solid-state synthesis. ► Products have high surface area suitable for ceramic processing. ► Product composition is dictated by both kinetic and thermodynamic control. ► A revised phase diagram of the Ca–Co–O system is proposed. - Abstract: The synthesis of mixed phases in the Ca–Co–O system using the Pechini method was investigated. The phases CaCo{sub 2}O{sub 4}, Ca{sub 3}Co{sub 4}O{sub 9} and Ca{sub 3}Co{sub 2}O{sub 6}, which can be expressed in terms of the molar ratios of the binary oxides (CaO:Co{sub 2}O{sub 3}) as (1:1), (3:2) and (3:1) respectively, were obtained in pure form. Powder X-ray diffraction data showed they are comparable with materials obtained by conventional solid-state synthesis. The mild synthesis conditions of the Pechini method allowed the evolution of the Ca–Co–O phases to be studied as a function of temperature and heating time. Both variables have a strong influence on the composition of the products, indicating that both kinetic and thermodynamic factors play a role, with the former being of more importance at lower temperatures. The (1:1) phase, previously not identified in the phase diagram of the Ca–Co–O system, was obtained preferentially across the composition range below ca. 650 °C. The (3:2) phase was preferred until ca. 800 °C. At even higher temperatures, the (3:1) phase is obtained. The upper thermal stability limit of mixed phases in the Ca–Co–O system increases with the Ca:Co ratio. An updated phase diagram for the Ca–Co–O system is proposed.

Vorinostat in patients with advanced malignant pleural mesothelioma who have progressed on previous chemotherapy (VANTAGE-014): a phase 3, double-blind, randomised, placebo-controlled trial.

Science.gov (United States)

Krug, Lee M; Kindler, Hedy L; Calvert, Hilary; Manegold, Christian; Tsao, Anne S; Fennell, Dean; Öhman, Ronny; Plummer, Ruth; Eberhardt, Wilfried E E; Fukuoka, Kazuya; Gaafar, Rabab M; Lafitte, Jean-Jacques; Hillerdal, Gunnar; Chu, Quincy; Buikhuisen, Wieneke A; Lubiniecki, Gregory M; Sun, Xing; Smith, Margaret; Baas, Paul

2015-04-01

Vorinostat is a histone deacetylase inhibitor that changes gene expression and protein activity. On the basis of the clinical benefit reported in patients with malignant pleural mesothelioma treated in a phase 1 study of vorinostat, we designed this phase 3 trial to investigate whether vorinostat given as a second-line or third-line therapy improved patients' overall survival. This double-blind, randomised, placebo-controlled trial was done in 90 international centres. Patients with measurable advanced malignant pleural mesothelioma and disease progression after one or two previous systemic regimens were eligible. After stratification for Karnofsky performance status, histology, and number of previous chemotherapy regimens, patients were randomly assigned (1:1) by use of an interactive voice response system with a block size of four to either treatment with vorinostat or placebo. Patients received oral vorinostat 300 mg (or matching placebo) twice daily on days 1, 2, 3, 8, 9, 10, 15, 16, and 17 of a 21-day cycle. The primary endpoints were overall survival and safety and tolerability of vorinostat. The primary efficacy comparison was done in the intention-to-treat population, and safety and tolerability was assessed in the treated population. This trial is registered with ClinicalTrials.gov, number NCT00128102. From July 12, 2005, to Feb 14, 2011, 661 patients were enrolled and randomly assigned to receive either vorinostat (n=329) or placebo (n=332) and included in the intention-to-treat analysis. Median overall survival for vorinostat was 30·7 weeks (95% CI 26·7-36·1) versus 27·1 weeks (23·1-31·9) for placebo (hazard ratio 0·98, 95% CI 0·83-1·17, p=0·86). The most common grade 3 or worse adverse events for patients treated with vorinostat were fatigue or malaise (51 [16%] patients in the vorinostat group vs 25 [8%] in the placebo group]) and dyspnoea (35 [11%] vs 45 [14%]). In this randomised trial, vorinostat given as a second-line or third

A Phase Current Reconstruction Approach for Three-Phase Permanent-Magnet Synchronous Motor Drive

Directory of Open Access Journals (Sweden)

Hao Yan

2016-10-01

Full Text Available Three-phase permanent-magnet synchronous motors (PMSMs are widely used in renewable energy applications such as wind power generation, tidal energy and electric vehicles owing to their merits such as high efficiency, high precision and high reliability. To reduce the cost and volume of the drive system, techniques of reconstructing three-phase current using a single current sensor have been reported for three-phase alternating current (AC control system using the power converts. In existing studies, the reconstruction precision is largely influenced by reconstructing dead zones on the Space Vector Pulse Width Modulation (SVPWM plane, which requires other algorithms to compensate either by modifying PWM modulation or by phase-shifting of the PWM signal. In this paper, a novel extended phase current reconstruction approach for PMSM drive is proposed. Six novel installation positions are obtained by analyzing the sampling results of the current paths between each two power switches. By arranging the single current sensor at these positions, the single current sensor is sampled during zero voltage vectors (ZVV without modifying the PWM signals. This proposed method can reconstruct the three-phase currents without any complex algorithms and is available in the sector boundary region and low modulation region. Finally, this method is validated by experiments.

Competing failure analysis in phased-mission systems with functional dependence in one of phases

International Nuclear Information System (INIS)

Wang, Chaonan; Xing, Liudong; Levitin, Gregory

2012-01-01

This paper proposes an algorithm for the reliability analysis of non-repairable phased-mission systems (PMS) subject to competing failure propagation and isolation effects. A failure originating from a system component which causes extensive damage to other system components is a propagated failure. When the propagated failure affects all the system components, causing the entire system failure, a propagated failure with global effect (PFGE) is said to occur. However, the failure propagation can be isolated in systems subject to functional dependence (FDEP) behavior, where the failure of a component (referred to as trigger component) causes some other components (referred to as dependent components) to become inaccessible or unusable (isolated from the system), and thus further failures from these dependent components have no effect on the system failure behavior. On the other hand, if any PFGE from dependent components occurs before the trigger failure, the failure propagation effect takes place, causing the overall system failure. In summary, there are two distinct consequences of a PFGE due to the competition between the failure isolation and failure propagation effects in the time domain. Existing works on such competing failures focus only on single-phase systems. However, many real-world systems are phased-mission systems (PMS), which involve multiple, consecutive and non-overlapping phases of operations or tasks. Consideration of competing failures for PMS is a challenging and difficult task because PMS exhibit dynamics in the system configuration and component behavior as well as statistical dependencies across phases for a given component. This paper proposes a combinatorial method to address the competing failure effects in the reliability analysis of binary non-repairable PMS. The proposed method is verified using a Markov-based method through a numerical example. Different from the Markov-based approach that is limited to exponential distribution, the

Coupled gamma/alpha phase transformations in low-carbon steels

Science.gov (United States)

Mizutani, Yasushi

Since steels have been the most prevalently utilized materials for many years, the desire for steels with low alloying components with a well-balanced combination of high strength and toughness is increasing. Low carbon steels consisting of bainitic microstructures are ideally suited to meeting such technological and economic requirements. Thus it is extremely important to fully clarify the mechanism of bainite formation in order to produce this type of engineering steel by optimized alloy and process design. This research focuses on understanding the mechanism of coupled displacive/diffusional gamma/alpha transformation in low-carbon steels including bainitic and martensitic transformation, and establishing a more comprehensive and physically rational computational model for predictive control of coupled gamma/alpha transformation phenomena. Models for coupled gamma/alpha phase transformation proposed in this study are based on a mechanistic and unified theory and the following assumptions: (1) The energy dissipation due to interface motion can be linearly combined with the energy dissipation due to carbon diffusion. (2) The carbon concentrations at the interface in both gamma and alpha phases are constrained by an interface solute trapping law. (3) Interface motion during nucleation is also governed by the carbon diffusion field velocity. (4) The response function of glissile interface motion can be expressed in the form of thermally activated dislocation glide. In contrast to the conventional semi-empirical models of the previous literature, the computational model proposed in this study is demonstrated to successfully provide a comprehensive and quantitative prediction of the effects of temperature, composition, microstructure, and the interactions among them. This includes the effects of substitutional solutes, morphology of the parent gamma phase, density of nucleation sites, temperature dependent variation of flow stress of matrix, and dynamic recovery of

Penalized maximum likelihood reconstruction for x-ray differential phase-contrast tomography

International Nuclear Information System (INIS)

Brendel, Bernhard; Teuffenbach, Maximilian von; Noël, Peter B.; Pfeiffer, Franz; Koehler, Thomas

2016-01-01

Purpose: The purpose of this work is to propose a cost function with regularization to iteratively reconstruct attenuation, phase, and scatter images simultaneously from differential phase contrast (DPC) acquisitions, without the need of phase retrieval, and examine its properties. Furthermore this reconstruction method is applied to an acquisition pattern that is suitable for a DPC tomographic system with continuously rotating gantry (sliding window acquisition), overcoming the severe smearing in noniterative reconstruction. Methods: We derive a penalized maximum likelihood reconstruction algorithm to directly reconstruct attenuation, phase, and scatter image from the measured detector values of a DPC acquisition. The proposed penalty comprises, for each of the three images, an independent smoothing prior. Image quality of the proposed reconstruction is compared to images generated with FBP and iterative reconstruction after phase retrieval. Furthermore, the influence between the priors is analyzed. Finally, the proposed reconstruction algorithm is applied to experimental sliding window data acquired at a synchrotron and results are compared to reconstructions based on phase retrieval. Results: The results show that the proposed algorithm significantly increases image quality in comparison to reconstructions based on phase retrieval. No significant mutual influence between the proposed independent priors could be observed. Further it could be illustrated that the iterative reconstruction of a sliding window acquisition results in images with substantially reduced smearing artifacts. Conclusions: Although the proposed cost function is inherently nonconvex, it can be used to reconstruct images with less aliasing artifacts and less streak artifacts than reconstruction methods based on phase retrieval. Furthermore, the proposed method can be used to reconstruct images of sliding window acquisitions with negligible smearing artifacts

Optical multiple-image encryption based on multiplane phase retrieval and interference

International Nuclear Information System (INIS)

Chen, Wen; Chen, Xudong

2011-01-01

In this paper, we propose a new method for optical multiple-image encryption based on multiplane phase retrieval and interference. An optical encoding system is developed in the Fresnel domain. A phase-only map is iteratively extracted based on a multiplane phase retrieval algorithm, and multiple plaintexts are simultaneously encrypted. Subsequently, the extracted phase-only map is further encrypted into two phase-only masks based on a non-iterative interference algorithm. During image decryption, the advantages and security of the proposed optical cryptosystem are analyzed. Numerical results are presented to demonstrate the validity of the proposed optical multiple-image encryption method

Optimizing adaptive design for Phase 2 dose-finding trials incorporating long-term success and financial considerations: A case study for neuropathic pain.

Science.gov (United States)

Gao, Jingjing; Nangia, Narinder; Jia, Jia; Bolognese, James; Bhattacharyya, Jaydeep; Patel, Nitin

2017-06-01

In this paper, we propose an adaptive randomization design for Phase 2 dose-finding trials to optimize Net Present Value (NPV) for an experimental drug. We replace the traditional fixed sample size design (Patel, et al., 2012) by this new design to see if NPV from the original paper can be improved. Comparison of the proposed design to the previous design is made via simulations using a hypothetical example based on a Diabetic Neuropathic Pain Study. Copyright © 2017 Elsevier Inc. All rights reserved.

Security-enhanced phase encryption assisted by nonlinear optical correlation via sparse phase

International Nuclear Information System (INIS)

Chen, Wen; Chen, Xudong; Wang, Xiaogang

2015-01-01

We propose a method for security-enhanced phase encryption assisted by a nonlinear optical correlation via a sparse phase. Optical configurations are established based on a phase retrieval algorithm for embedding an input image and the secret data into phase-only masks. We found that when one or a few phase-only masks generated during data hiding are sparse, it is possible to integrate these sparse masks into those phase-only masks generated during the encoding of the input image. Synthesized phase-only masks are used for the recovery, and sparse distributions (i.e., binary maps) for generating the incomplete phase-only masks are considered as additional parameters for the recovery of secret data. It is difficult for unauthorized receivers to know that a useful phase has been sparsely distributed in the finally generated phase-only masks for secret-data recovery. Only when the secret data are correctly verified can the input image obtained with valid keys be claimed as targeted information. (paper)

78 FR 52872 - Airworthiness Directives; 328 Support Services GmbH (Type Certificate Previously Held by AvCraft...

Science.gov (United States)

2013-08-27

... Services GmbH (Type Certificate Previously Held by AvCraft Aerospace GmbH; Fairchild Dornier GmbH; Dornier... certain 328 Support Services GmbH (Type Certificate Previously Held by AvCraft Aerospace GmbH; Fairchild... send any written relevant data, views, or arguments about this proposed AD. Send your comments to an...

A novel single-phase phase space-based voltage mode controller for distributed static compensator to improve voltage profile of distribution systems

International Nuclear Information System (INIS)

Shokri, Abdollah; Shareef, Hussain; Mohamed, Azah; Farhoodnea, Masoud; Zayandehroodi, Hadi

2014-01-01

Highlights: • A new phase space based voltage mode controller for D-STATCOM was proposed. • The proposed compensator was tested to mitigate voltage disturbances in distribution systems. • Voltage fluctuation, voltage sag and voltage swell are considered to evaluate the performance of the proposed compensator. - Abstract: Distribution static synchronous compensator (D-STATCOM) has been developed and attained a great interest to compensate the power quality disturbances of distribution systems. In this paper, a novel single-phase control scheme for D-STATCOM is proposed to improve voltage profile at the Point of Common Coupling (PCC). The proposed voltage mode (VM) controller is based on the phase space algorithm, which is able to rapidly detect and mitigate any voltage deviations from reference voltage including voltage sags and voltage swells. To investigate the efficiency and accuracy of the proposed compensator, a system is modeled using Matlab/Simulink. The simulation results approve the capability of the proposed VM controller to provide a regulated and disturbance-free voltage for the connected loads at the PCC

Two-harmonic complex spectral-domain optical coherence tomography using achromatic sinusoidal phase modulation

Science.gov (United States)

Lu, Sheng-Hua; Huang, Siang-Ru; Chou, Che-Chung

2018-03-01

We resolve the complex conjugate ambiguity in spectral-domain optical coherence tomography (SD-OCT) by using achromatic two-harmonic method. Unlike previous researches, the optical phase of the fiber interferometer is modulated by an achromatic phase shifter based on an optical delay line. The achromatic phase modulation leads to a wavelength-independent scaling coefficient for the two harmonics. Dividing the mean absolute value of the first harmonic by that of the second harmonic in a B-scan interferogram directly gives the scaling coefficient. It greatly simplifies the determination of the magnitude ratio between the two harmonics without the need of third harmonic and cumbersome iterative calculations. The inverse fast Fourier transform of the complex-valued interferogram constructed with the scaling coefficient, first and second harmonics yields a full-range OCT image. Experimental results confirm the effectiveness of the proposed achromatic two-harmonic technique for suppressing the mirror artifacts in SD-OCT images.

Phase-field-based lattice Boltzmann modeling of large-density-ratio two-phase flows

Science.gov (United States)

Liang, Hong; Xu, Jiangrong; Chen, Jiangxing; Wang, Huili; Chai, Zhenhua; Shi, Baochang

2018-03-01

In this paper, we present a simple and accurate lattice Boltzmann (LB) model for immiscible two-phase flows, which is able to deal with large density contrasts. This model utilizes two LB equations, one of which is used to solve the conservative Allen-Cahn equation, and the other is adopted to solve the incompressible Navier-Stokes equations. A forcing distribution function is elaborately designed in the LB equation for the Navier-Stokes equations, which make it much simpler than the existing LB models. In addition, the proposed model can achieve superior numerical accuracy compared with previous Allen-Cahn type of LB models. Several benchmark two-phase problems, including static droplet, layered Poiseuille flow, and spinodal decomposition are simulated to validate the present LB model. It is found that the present model can achieve relatively small spurious velocity in the LB community, and the obtained numerical results also show good agreement with the analytical solutions or some available results. Lastly, we use the present model to investigate the droplet impact on a thin liquid film with a large density ratio of 1000 and the Reynolds number ranging from 20 to 500. The fascinating phenomena of droplet splashing is successfully reproduced by the present model and the numerically predicted spreading radius exhibits to obey the power law reported in the literature.

Design and Development of a compact and ruggest phase and flouresence microscope for space utilization, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — In this SBIR Phase 1 we propose to develop a novel microscope by integrating Fourier phase contrast microscopy (FPCM) and epi-fluorescence microscopy. In FPCM, the...

Gas hydrate phase equilibria measurement techniques and phase rule considerations

International Nuclear Information System (INIS)

Beltran, Juan G.; Bruusgaard, Hallvard; Servio, Phillip

2012-01-01

Highlights: → Inconsistencies found in hydrate literature. → Clarification to the number of variables needed to satisfy and justify equilibrium data. → Application of phase rule to mixed hydrate systems. → Thermodynamically consistent format to present data. - Abstract: A brief review of the Gibbs phase rule for non-reacting systems and its correct application to clathrate hydrates is presented. Clarification is provided for a common mistake found in hydrate phase-equilibria literature, whereby initial compositions are used as intensive variables to satisfy the Gibbs phase rule instead of the equilibrium values. The system of (methane + carbon dioxide + water) under (hydrate + liquid + vapor) equilibrium is used as a case study to illustrate key points and suggestions to improve experimental techniques are proposed.

The evaluation of doctoral thesis. A model proposal

Directory of Open Access Journals (Sweden)

de-Miguel, Mario

2010-04-01

Full Text Available The aim of this work is the development of a model that can be used as a framework for evaluators and PhD tribunal members, either during the previous administrative processing phase or at the actual exposition and viva on doctoral dissertations. To this end, once reviewed the existing literature and normative, a new proposal is laid out on the main aspects and criteria to be analysed and assessed from any given scientific work, thus introducing a tool that facilitates and specifies this work. Our model is intended to be an open proposal on which we would welcome any contribution and suggestion. El objetivo del presente trabajo es la elaboración de un modelo que pueda ser utilizado como marco de referencia por los evaluadores y miembros de tribunales de las tesis doctorales tanto en la fase previa a la tramitación administrativa como en el acto de exposición y defensa de la misma. Para ello, una vez revisada la literatura y la normativa vigente al respecto, efectuamos una propuesta sobre los principales aspectos y criterios que deben ser objeto de análisis y valoración en todo trabajo científico, y presentamos una herramienta que facilita y precisa esta tarea. Nuestro modelo constituye una propuesta abierta sobre la que esperamos aportaciones y sugerencias.

CrowdPhase: crowdsourcing the phase problem

International Nuclear Information System (INIS)

Jorda, Julien; Sawaya, Michael R.; Yeates, Todd O.

2014-01-01

The idea of attacking the phase problem by crowdsourcing is introduced. Using an interactive, multi-player, web-based system, participants work simultaneously to select phase sets that correspond to better electron-density maps in order to solve low-resolution phasing problems. The human mind innately excels at some complex tasks that are difficult to solve using computers alone. For complex problems amenable to parallelization, strategies can be developed to exploit human intelligence in a collective form: such approaches are sometimes referred to as ‘crowdsourcing’. Here, a first attempt at a crowdsourced approach for low-resolution ab initio phasing in macromolecular crystallography is proposed. A collaborative online game named CrowdPhase was designed, which relies on a human-powered genetic algorithm, where players control the selection mechanism during the evolutionary process. The algorithm starts from a population of ‘individuals’, each with a random genetic makeup, in this case a map prepared from a random set of phases, and tries to cause the population to evolve towards individuals with better phases based on Darwinian survival of the fittest. Players apply their pattern-recognition capabilities to evaluate the electron-density maps generated from these sets of phases and to select the fittest individuals. A user-friendly interface, a training stage and a competitive scoring system foster a network of well trained players who can guide the genetic algorithm towards better solutions from generation to generation via gameplay. CrowdPhase was applied to two synthetic low-resolution phasing puzzles and it was shown that players could successfully obtain phase sets in the 30° phase error range and corresponding molecular envelopes showing agreement with the low-resolution models. The successful preliminary studies suggest that with further development the crowdsourcing approach could fill a gap in current crystallographic methods by making it

CrowdPhase: crowdsourcing the phase problem

Energy Technology Data Exchange (ETDEWEB)

Jorda, Julien; Sawaya, Michael R. [Institute for Genomics and Proteomics, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States); Yeates, Todd O., E-mail: yeates@mbi.ucla.edu [Institute for Genomics and Proteomics, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States); Molecular Biology Institute, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States); University of California, 611 Charles Young Drive East, Los Angeles, CA 90095 (United States)

2014-06-01

The idea of attacking the phase problem by crowdsourcing is introduced. Using an interactive, multi-player, web-based system, participants work simultaneously to select phase sets that correspond to better electron-density maps in order to solve low-resolution phasing problems. The human mind innately excels at some complex tasks that are difficult to solve using computers alone. For complex problems amenable to parallelization, strategies can be developed to exploit human intelligence in a collective form: such approaches are sometimes referred to as ‘crowdsourcing’. Here, a first attempt at a crowdsourced approach for low-resolution ab initio phasing in macromolecular crystallography is proposed. A collaborative online game named CrowdPhase was designed, which relies on a human-powered genetic algorithm, where players control the selection mechanism during the evolutionary process. The algorithm starts from a population of ‘individuals’, each with a random genetic makeup, in this case a map prepared from a random set of phases, and tries to cause the population to evolve towards individuals with better phases based on Darwinian survival of the fittest. Players apply their pattern-recognition capabilities to evaluate the electron-density maps generated from these sets of phases and to select the fittest individuals. A user-friendly interface, a training stage and a competitive scoring system foster a network of well trained players who can guide the genetic algorithm towards better solutions from generation to generation via gameplay. CrowdPhase was applied to two synthetic low-resolution phasing puzzles and it was shown that players could successfully obtain phase sets in the 30° phase error range and corresponding molecular envelopes showing agreement with the low-resolution models. The successful preliminary studies suggest that with further development the crowdsourcing approach could fill a gap in current crystallographic methods by making it

Phase-unwrapping algorithm by a rounding-least-squares approach

Science.gov (United States)

Juarez-Salazar, Rigoberto; Robledo-Sanchez, Carlos; Guerrero-Sanchez, Fermin

2014-02-01

A simple and efficient phase-unwrapping algorithm based on a rounding procedure and a global least-squares minimization is proposed. Instead of processing the gradient of the wrapped phase, this algorithm operates over the gradient of the phase jumps by a robust and noniterative scheme. Thus, the residue-spreading and over-smoothing effects are reduced. The algorithm's performance is compared with four well-known phase-unwrapping methods: minimum cost network flow (MCNF), fast Fourier transform (FFT), quality-guided, and branch-cut. A computer simulation and experimental results show that the proposed algorithm reaches a high-accuracy level than the MCNF method by a low-computing time similar to the FFT phase-unwrapping method. Moreover, since the proposed algorithm is simple, fast, and user-free, it could be used in metrological interferometric and fringe-projection automatic real-time applications.

Analyzing phase diagrams and phase transitions in networked competing populations

Science.gov (United States)

Ni, Y.-C.; Yin, H. P.; Xu, C.; Hui, P. M.

2011-03-01

Phase diagrams exhibiting the extent of cooperation in an evolutionary snowdrift game implemented in different networks are studied in detail. We invoke two independent payoff parameters, unlike a single payoff often used in most previous works that restricts the two payoffs to vary in a correlated way. In addition to the phase transition points when a single payoff parameter is used, phase boundaries separating homogeneous phases consisting of agents using the same strategy and a mixed phase consisting of agents using different strategies are found. Analytic expressions of the phase boundaries are obtained by invoking the ideas of the last surviving patterns and the relative alignments of the spectra of payoff values to agents using different strategies. In a Watts-Strogatz regular network, there exists a re-entrant phenomenon in which the system goes from a homogeneous phase into a mixed phase and re-enters the homogeneous phase as one of the two payoff parameters is varied. The non-trivial phase diagram accompanying this re-entrant phenomenon is quantitatively analyzed. The effects of noise and cooperation in randomly rewired Watts-Strogatz networks are also studied. The transition between a mixed phase and a homogeneous phase is identify to belong to the directed percolation universality class. The methods used in the present work are applicable to a wide range of problems in competing populations of networked agents.

Phase Startup Initiative Phases 3 and 4 Test Plan and Test Specification ( OCRWM)

Energy Technology Data Exchange (ETDEWEB)

PAJUNEN, A.L.; LANGEVIN, M.J.

2000-08-07

Construction for the Spent Nuclear Fuel (SNF) Project facilities is continuing per the Level III Baseline Schedule, and installation of the Fuel Retrieval System (FRS) and Integrated Water Treatment System (IWTS) in K West Basin is now complete. In order to accelerate the project, a phased start up strategy to initiate testing of the FRS and IWTS early in the overall project schedule was proposed (Williams 1999). Wilkinson (1999) expands the definition of the original proposal into four functional testing phases of the Phased Startup Initiative (PSI). Phases 1 and 2 are based on performing functional tests using dummy fuel. This test plan provides overall guidance for Phase 3 and 4 tests, which are performed using actual irradiated N fuel assemblies. The overall objective of the Phase 3 and 4 testing is to verify how the FRS and IWTS respond while processing actual fuel. Conducting these tests early in the project schedule will allow identification and resolution of equipment and process problems before they become activities on the start-up critical path. The specific objectives of this test plan are to: Define the Phase 3 and 4 test scope for the FRS and IWTS; Provide detailed test requirements that can be used to write the specific test procedures; Define data required and measurements to be taken. Where existing methods to obtain these do not exist, enough detail will be provided to define required additional equipment; and Define specific test objectives and acceptance criteria.

Phase Startup Initiative Phases 3 and 4 Test Plan and Test Specification (OCRWM)

International Nuclear Information System (INIS)

PAJUNEN, A.L.; LANGEVIN, M.J.

2000-01-01

Construction for the Spent Nuclear Fuel (SNF) Project facilities is continuing per the Level III Baseline Schedule, and installation of the Fuel Retrieval System (FRS) and Integrated Water Treatment System (IWTS) in K West Basin is now complete. In order to accelerate the project, a phased start up strategy to initiate testing of the FRS and IWTS early in the overall project schedule was proposed (Williams 1999). Wilkinson (1999) expands the definition of the original proposal into four functional testing phases of the Phased Startup Initiative (PSI). Phases 1 and 2 are based on performing functional tests using dummy fuel. This test plan provides overall guidance for Phase 3 and 4 tests, which are performed using actual irradiated N fuel assemblies. The overall objective of the Phase 3 and 4 testing is to verify how the FRS and IWTS respond while processing actual fuel. Conducting these tests early in the project schedule will allow identification and resolution of equipment and process problems before they become activities on the start-up critical path. The specific objectives of this test plan are to: Define the Phase 3 and 4 test scope for the FRS and IWTS; Provide detailed test requirements that can be used to write the specific test procedures; Define data required and measurements to be taken. Where existing methods to obtain these do not exist, enough detail will be provided to define required additional equipment; and Define specific test objectives and acceptance criteria

A wavelet phase filter for emission tomography

International Nuclear Information System (INIS)

Olsen, E.T.; Lin, B.

1995-01-01

The presence of a high level of noise is a characteristic in some tomographic imaging techniques such as positron emission tomography (PET). Wavelet methods can smooth out noise while preserving significant features of images. Mallat et al. proposed a wavelet based denoising scheme exploiting wavelet modulus maxima, but the scheme is sensitive to noise. In this study, the authors explore the properties of wavelet phase, with a focus on reconstruction of emission tomography images. Specifically, they show that the wavelet phase of regular Poisson noise under a Haar-type wavelet transform converges in distribution to a random variable uniformly distributed on [0, 2π). They then propose three wavelet-phase-based denoising schemes which exploit this property: edge tracking, local phase variance thresholding, and scale phase variation thresholding. Some numerical results are also presented. The numerical experiments indicate that wavelet phase techniques show promise for wavelet based denoising methods

Nucleation mechanism for the direct graphite-to-diamond phase transition

Science.gov (United States)

Khaliullin, Rustam Z.; Eshet, Hagai; Kühne, Thomas D.; Behler, Jörg; Parrinello, Michele

2011-09-01

Graphite and diamond have comparable free energies, yet forming diamond from graphite in the absence of a catalyst requires pressures that are significantly higher than those at equilibrium coexistence. At lower temperatures, the formation of the metastable hexagonal polymorph of diamond is favoured instead of the more stable cubic diamond. These phenomena cannot be explained by the concerted mechanism suggested in previous theoretical studies. Using an ab initio quality neural-network potential, we carried out a large-scale study of the graphite-to-diamond transition assuming that it occurs through nucleation. The nucleation mechanism accounts for the observed phenomenology and reveals its microscopic origins. We demonstrate that the large lattice distortions that accompany the formation of diamond nuclei inhibit the phase transition at low pressure, and direct it towards the hexagonal diamond phase at higher pressure. The proposed nucleation mechanism should improve our understanding of structural transformations in a wide range of carbon-based materials.

Short- and long- term ageing effects on the phase transformation in Au-49.5 at % Cd

International Nuclear Information System (INIS)

Kelly, G.L.; Finlayson, T.R.; Ersez, T.; Smith, T.F.

1999-01-01

Full text: Gold-Cadmium alloys of approximately equiatomic composition are widely studied as model systems for the shape-memory effect and 'rubber-elasticity'. Rubber-elasticity occurs after ageing for a time in the low-temperature martensite phase. This ageing is accompanied by an increase in the martensite → austenite phase transformation temperature (A s ). The ageing dependence of the transformation is a critical problem when finding applications for the shape-memory effect in these materials. The origin of the ageing effect is controversial with proposed mechanisms including stabilisation of the martensite by a change in short range order or pinning of the martensite by defects. In the present study, a Au-49.5at%Cd alloy has been subjected to a series of ageing times and the phase transformation temperatures monitored using a push-rod dilatometer. One test series comprising a range of ageing times was completed and then the sample was aged in the martensite phase for several months before re-testing. Both test series show that ageing in the martensite phase increases the temperature of the reverse transformation (A s ) as expected. Previous work had suggested that all effects of any previous ageing treatments were obliterated by a single cycle through the martensite-austenite-martensite transformations. The present study shows that this is not the case. The A f and A s temperatures for each ageing time in the test series had increased by several degrees after a year of ageing and this increase was maintained despite repeated cycling through the phase transformations

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

DEFF Research Database (Denmark)

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

2017-01-01

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

Effective interactions approach to phase stability in alloys under irradiation

International Nuclear Information System (INIS)

Enrique, R.A.; Bellon, P.

1999-01-01

Phase stability in alloys under irradiation is studied considering effective thermodynamic potentials. A simple kinetic model of a binary alloy with phase separation is investigated. Time evolution in the alloy results form two competing dynamics: thermal diffusion, and irradiation induced ballistic exchanges. The dynamical (steady state) phase diagram is evaluated exactly performing Kinetic Monte Carlo simulations. The solution is then compared to two theoretical frameworks: the effective quasi-interactions model as proposed by Vaks and Kamishenko, and the effective free energy model as proposed by Martin. New developments of these models are proposed to allow for quantitative comparisons. Both theoretical frameworks yield fairly good approximations to the dynamical phase diagram

Effective interactions approach to phase stability in alloys under irradiation

International Nuclear Information System (INIS)

Enrique, R.A.; Bellon, P.

1999-01-01

Phase stability in alloys under irradiation is studied considering effective thermodynamic potentials. A simple kinetic model of a binary alloy with phase separation is investigated. Time evolution in the alloy results from two competing dynamics: thermal diffusion, and irradiation induced ballistic exchanges The dynamical (steady state) phase diagram is evaluated exactly performing Kinetic Monte Carlo simulations. The solution is then compared to two theoretical frameworks: the effective quasi-interactions model as proposed by Vaks and Kamishenko, and the effective free energy model as proposed by Martin. New developments of these models are proposed to allow for quantitative comparisons. Both theoretical frameworks yield fairly good approximations to the dynamical phase diagram

Phase difference estimation method based on data extension and Hilbert transform

International Nuclear Information System (INIS)

Shen, Yan-lin; Tu, Ya-qing; Chen, Lin-jun; Shen, Ting-ao

2015-01-01

To improve the precision and anti-interference performance of phase difference estimation for non-integer periods of sampling signals, a phase difference estimation method based on data extension and Hilbert transform is proposed. Estimated phase difference is obtained by means of data extension, Hilbert transform, cross-correlation, auto-correlation, and weighted phase average. Theoretical analysis shows that the proposed method suppresses the end effects of Hilbert transform effectively. The results of simulations and field experiments demonstrate that the proposed method improves the anti-interference performance of phase difference estimation and has better performance of phase difference estimation than the correlation, Hilbert transform, and data extension-based correlation methods, which contribute to improving the measurement precision of the Coriolis mass flowmeter. (paper)

Phase transitions and self-organized criticality in networks of stochastic spiking neurons.

Science.gov (United States)

Brochini, Ludmila; de Andrade Costa, Ariadne; Abadi, Miguel; Roque, Antônio C; Stolfi, Jorge; Kinouchi, Osame

2016-11-07

Phase transitions and critical behavior are crucial issues both in theoretical and experimental neuroscience. We report analytic and computational results about phase transitions and self-organized criticality (SOC) in networks with general stochastic neurons. The stochastic neuron has a firing probability given by a smooth monotonic function Φ(V) of the membrane potential V, rather than a sharp firing threshold. We find that such networks can operate in several dynamic regimes (phases) depending on the average synaptic weight and the shape of the firing function Φ. In particular, we encounter both continuous and discontinuous phase transitions to absorbing states. At the continuous transition critical boundary, neuronal avalanches occur whose distributions of size and duration are given by power laws, as observed in biological neural networks. We also propose and test a new mechanism to produce SOC: the use of dynamic neuronal gains - a form of short-term plasticity probably located at the axon initial segment (AIS) - instead of depressing synapses at the dendrites (as previously studied in the literature). The new self-organization mechanism produces a slightly supercritical state, that we called SOSC, in accord to some intuitions of Alan Turing.

77 FR 15980 - Airworthiness Directives; Alpha Aviation Concept Limited (Type Certificate Previously Held by...

Science.gov (United States)

2012-03-19

... Concept Limited (Type Certificate Previously Held by Alpha Aviation Design Limited) Airplanes AGENCY... rulemaking (NPRM). SUMMARY: We propose to adopt a new airworthiness directive (AD) for Alpha Aviation Concept... condition on an aviation product. The MCAI describes the unsafe condition as oil lines fitted to affected...

76 FR 41432 - Airworthiness Directives; Gulfstream Aerospace LP (Type Certificate Previously Held by Israel...

Science.gov (United States)

2011-07-14

... Aerospace LP (Type Certificate Previously Held by Israel Aircraft Industries, Ltd.) Model Galaxy, Gulfstream... proposed AD. Discussion The Civil Aviation Authority (CAA), which is the aviation authority for Israel, has... Held by Israel Aircraft Industries, Ltd.): Docket No. FAA-2011-0716; Directorate Identifier 2011-NM-013...

75 FR 36296 - Airworthiness Directives; Gulfstream Aerospace LP (Type Certificate Previously Held by Israel...

Science.gov (United States)

2010-06-25

... Airworthiness Directives; Gulfstream Aerospace LP (Type Certificate Previously Held by Israel Aircraft... contact we receive about this proposed AD. Discussion The Civil Aviation Authority of Israel (CAAI), which is the aviation authority for Israel, has issued Israeli Airworthiness Directive 01-10-01-07R1, dated...

Phase II activity of belinostat (PXD-101), carboplatin, and paclitaxel in women with previously treated ovarian cancer

DEFF Research Database (Denmark)

Dizon, Don S; Damstrup, Lars; Finkler, Neil J

2012-01-01

specifically for women with recurrent epithelial ovarian cancer (EOC). METHODS: Thirty-five women were treated on the phase 2 expansion cohort. BelCap was given as follows: belinostat, 1000 mg/m² daily for 5 days with carboplatin, AUC 5; and paclitaxel, 175 mg/m² given on day 3 of a 21-day cycle. The primary...

Spectrophotometric determination of uranium by previous extraction chromatography separation in polimetalic mineral, phosphorites and technological licours

International Nuclear Information System (INIS)

Moreno Bermudez, J.; Cabrera Quevedo, C.; Alfonso Mendez, L.; Rodriguez Aguilera, M.

1994-01-01

The development of an analytical procedure for spectrophotometric determination of uranium in polimetalic mineral, phosphorites and technological licours is described. The method is based on the previous separation of interfering elements by extraction chromatography and on spectrophotometric determination of uranium (IV) with arsenazo III in concentrated hydrochloric acid. Tributyl phosphate impregnate on politetrafluoroethylene is used as stationary phase and 5.5 M nitric acid is used as movie phase. The influence of matrix-component elements was studies. The development procedure was applied to real samples, being the results compared with those obtained by other well established analytical methods like gamma-spectrometry, laser fluorimetric, spectrophotometry previous uranium separation by liquid liquid extraction and anion exchange. The reproducibility is evaluated and the detection limited has been established for each studied matrix. A procedure for correcting the thorium interference has been developed for samples with a Th/ 3U8O higher than 0.2

Catastrophic regime shifts in model ecological communities are true phase transitions

International Nuclear Information System (INIS)

Capitán, J A; Cuesta, J A

2010-01-01

Ecosystems often undergo abrupt regime shifts in response to gradual external changes. These shifts are theoretically understood as a regime switch between alternative stable states of the ecosystem dynamical response to smooth changes in external conditions. Usual models introduce nonlinearities in the macroscopic dynamics of the ecosystem that lead to different stable attractors among which the shift takes place. Here we propose an alternative explanation of catastrophic regime shifts based on a recent model that pictures ecological communities as systems in continuous fluctuation, according to certain transition probabilities, between different micro-states in the phase space of viable communities. We introduce a spontaneous extinction rate that accounts for gradual changes in external conditions, and upon variations on this control parameter the system undergoes a regime shift with similar features to those previously reported. Under our microscopic viewpoint we recover the main results obtained in previous theoretical and empirical work (anomalous variance, hysteresis cycles, trophic cascades). The model predicts a gradual loss of species in trophic levels from bottom to top near the transition. But more importantly, the spectral analysis of the transition probability matrix allows us to rigorously establish that we are observing the fingerprints, in a finite size system, of a true phase transition driven by background extinctions

Phase-I monitoring of standard deviations in multistage linear profiles

Science.gov (United States)

Kalaei, Mahdiyeh; Soleimani, Paria; Niaki, Seyed Taghi Akhavan; Atashgar, Karim

2018-03-01

In most modern manufacturing systems, products are often the output of some multistage processes. In these processes, the stages are dependent on each other, where the output quality of each stage depends also on the output quality of the previous stages. This property is called the cascade property. Although there are many studies in multistage process monitoring, there are fewer works on profile monitoring in multistage processes, especially on the variability monitoring of a multistage profile in Phase-I for which no research is found in the literature. In this paper, a new methodology is proposed to monitor the standard deviation involved in a simple linear profile designed in Phase I to monitor multistage processes with the cascade property. To this aim, an autoregressive correlation model between the stages is considered first. Then, the effect of the cascade property on the performances of three types of T 2 control charts in Phase I with shifts in standard deviation is investigated. As we show that this effect is significant, a U statistic is next used to remove the cascade effect, based on which the investigated control charts are modified. Simulation studies reveal good performances of the modified control charts.

Two-phase flow characterisation by nuclear magnetic resonance

International Nuclear Information System (INIS)

Leblond, J.; Javelot, S.; Lebrun, D.; Lebon, L.

1998-01-01

The results presented in this paper demonstrate the performance of the PFGSE-NMR to obtain a complete characterisation of two-phase flows. Different methods are proposed to characterise air-water flows in different regimes: stationary two-phase flows and flows in transient condition. Finally a modified PFGSE is proposed to analyse the turbulence of air-water bubbly flow. (author)

A GPS Phase-Locked Loop Performance Metric Based on the Phase Discriminator Output.

Science.gov (United States)

Stevanovic, Stefan; Pervan, Boris

2018-01-19

We propose a novel GPS phase-lock loop (PLL) performance metric based on the standard deviation of tracking error (defined as the discriminator's estimate of the true phase error), and explain its advantages over the popular phase jitter metric using theory, numerical simulation, and experimental results. We derive an augmented GPS phase-lock loop (PLL) linear model, which includes the effect of coherent averaging, to be used in conjunction with this proposed metric. The augmented linear model allows more accurate calculation of tracking error standard deviation in the presence of additive white Gaussian noise (AWGN) as compared to traditional linear models. The standard deviation of tracking error, with a threshold corresponding to half of the arctangent discriminator pull-in region, is shown to be a more reliable/robust measure of PLL performance under interference conditions than the phase jitter metric. In addition, the augmented linear model is shown to be valid up until this threshold, which facilitates efficient performance prediction, so that time-consuming direct simulations and costly experimental testing can be reserved for PLL designs that are much more likely to be successful. The effect of varying receiver reference oscillator quality on the tracking error metric is also considered.

High-field magnetic phase transitions and spin excitations in magnetoelectric LiNiPO4

DEFF Research Database (Denmark)

Toft-Petersen, Rasmus; Jensen, Jens; Jensen, Thomas Bagger Stibius

2011-01-01

The magnetically ordered phases and spin dynamics of magnetoelectric LiNiPO4 have been studied in fields up to 17.3 T along the c axis. Using neutron diffraction, we show that a previously proposed linearly polarized incommensurate (IC) structure exists only for temperatures just below the Neel...... temperature T-N. The ordered IC structure at the lowest temperatures is shown instead to be an elliptically polarized canted spiral for fields larger than 12 T. The transition between the two IC phases is of second order and takes place about 2 K below T-N. For mu H-0 > 16 T and temperatures below 10 K......, the spiral structure is found to lock in to a period of five crystallographic unit cells along the b axis. Based on the neutron-diffraction data, combined with detailed magnetization measurements along all three crystallographic axes, we establish the magnetic phase diagrams for fields up to 17.3 T along c...

Multispecies Coevolution Particle Swarm Optimization Based on Previous Search History

Directory of Open Access Journals (Sweden)

Danping Wang

2017-01-01

Full Text Available A hybrid coevolution particle swarm optimization algorithm with dynamic multispecies strategy based on K-means clustering and nonrevisit strategy based on Binary Space Partitioning fitness tree (called MCPSO-PSH is proposed. Previous search history memorized into the Binary Space Partitioning fitness tree can effectively restrain the individuals’ revisit phenomenon. The whole population is partitioned into several subspecies and cooperative coevolution is realized by an information communication mechanism between subspecies, which can enhance the global search ability of particles and avoid premature convergence to local optimum. To demonstrate the power of the method, comparisons between the proposed algorithm and state-of-the-art algorithms are grouped into two categories: 10 basic benchmark functions (10-dimensional and 30-dimensional, 10 CEC2005 benchmark functions (30-dimensional, and a real-world problem (multilevel image segmentation problems. Experimental results show that MCPSO-PSH displays a competitive performance compared to the other swarm-based or evolutionary algorithms in terms of solution accuracy and statistical tests.

Adaptive phase k-means algorithm for waveform classification

Science.gov (United States)

Song, Chengyun; Liu, Zhining; Wang, Yaojun; Xu, Feng; Li, Xingming; Hu, Guangmin

2018-01-01

Waveform classification is a powerful technique for seismic facies analysis that describes the heterogeneity and compartments within a reservoir. Horizon interpretation is a critical step in waveform classification. However, the horizon often produces inconsistent waveform phase, and thus results in an unsatisfied classification. To alleviate this problem, an adaptive phase waveform classification method called the adaptive phase k-means is introduced in this paper. Our method improves the traditional k-means algorithm using an adaptive phase distance for waveform similarity measure. The proposed distance is a measure with variable phases as it moves from sample to sample along the traces. Model traces are also updated with the best phase interference in the iterative process. Therefore, our method is robust to phase variations caused by the interpretation horizon. We tested the effectiveness of our algorithm by applying it to synthetic and real data. The satisfactory results reveal that the proposed method tolerates certain waveform phase variation and is a good tool for seismic facies analysis.

Tank waste remediation system retrieval and disposal mission - Phase 1: Financial analysis

International Nuclear Information System (INIS)

Bickford, J.C.

1998-01-01

In Section 1.0, an overview of the Financial Analysis was provided and summarized in Table 1 for both the Retrieval and Disposal program and the TWRS project life cycle. A table recaps the pre-Phase 1B analysis budget requirements as discussed in previous sections. Another table in this section shows a similar build-up of costs and the impact of proposed offsets and increases to the pre-Phase 1B analysis. The issues concerning the increased requirements in FY 1998/1999 and the recommended adjustments were discussed. The Phase 1B Program as recommended is achievable. Specific recommendations are as follows: (a) Adopt the revised project baseline as presented in the cited tables; (b) Incorporate the $248.5 million in allowances for risk into the baseline; (c) Develop detailed action plans to realize the costs reduction opportunities; (d) Incorporate site indirect and benefits reduction rates into baseline; (e) Delay non-critical path scope which can be moved beyond FY 1999, as indicated: and (f) Renegotiate the Tri-Party Agreement milestones associated with the current compliance unfunded list for FY 1998

Study of 18-Pulse Rectifier Utilizing Hexagon Connected 3-Phase to 9-Phase Transformer

Directory of Open Access Journals (Sweden)

Ahmad Saudi Samosir

2008-04-01

Full Text Available The 18-pulse converter, using Y or -connected differential autotransformer, is very interesting since it allows natural high power factor correction. The lowest input current harmonic components are the 17th and 19th. The Transformer is designed to feed three six-pulse bridge rectifiers displaced in phase by 200. This paper present a high power factor three-phase rectifier bases on 3-phase to 9-phase transformer and 18-pulse rectifier. The 9-phase polygon-connected transformer followed by 18-pulse diode rectifiers ensures the fundamental concept of natural power factor correction. Simulation results to verify the proposed concept are shown in this paper.

Sound speed during the QCD phase transition

International Nuclear Information System (INIS)

Nagasawa, Michiyasu; Yokoyama, Jun'ichi

1998-01-01

The Jeans scale is estimated during the coexistence epoch of quark-gluon and hadron phases in the first-order QCD phase transition. It is shown that, contrary to previous claims, reduction of the sound speed is so little that the phase transition does not affect evolution of cosmological density fluctuations appreciably. (author)

Geometric Phases for Mixed States in Trapped Ions

International Nuclear Information System (INIS)

Lu Hongxia

2006-01-01

The generalization of geometric phase from the pure states to the mixed states may have potential applications in constructing geometric quantum gates. We here investigate the mixed state geometric phases and visibilities of the trapped ion system in both non-degenerate and degenerate cases. In the proposed quantum system, the geometric phases are determined by the evolution time, the initial states of trapped ions, and the initial states of photons. Moreover, special periods are gained under which the geometric phases do not change with the initial states changing of photon parts in both non-degenerate and degenerate cases. The high detection efficiency in the ion trap system implies that the mixed state geometric phases proposed here can be easily tested.

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

NARCIS (Netherlands)

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

1995-01-01

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

Treatment response with mepolizumab in severe eosinophilic asthma patients with previous omalizumab treatment.

Science.gov (United States)

Magnan, A; Bourdin, A; Prazma, C M; Albers, F C; Price, R G; Yancey, S W; Ortega, H

2016-09-01

We performed post hoc analyses to evaluate the effect of humanized monoclonal antibody mepolizumab in patients with severe eosinophilic asthma previously treated with omalizumab. Data were collected from two randomized double-blind, placebo-controlled studies: MENSA (NCT01691521: 32-week treatment phase) and SIRIUS (NCT01691508: 24-week treatment phase). Active treatment was 75 mg intravenous mepolizumab (MENSA) or 100 mg subcutaneous mepolizumab (MENSA, SIRIUS). Patients had evidence of eosinophilic inflammation ≥150 cells/μl (at screening) or ≥300 cells/μl (during the previous year). Primary outcomes were the rate of exacerbations (MENSA) and the percentage reduction in oral corticosteroid (OCS) dose (SIRIUS). Other outcomes included lung function (forced expiratory volume in 1 s and morning peak expiratory flow), Asthma Control Questionnaire (ACQ-5), St George's Respiratory Questionnaire (SGRQ) scores, and safety. Overall, 576 patients were included from MENSA and 135 from SIRIUS, with 13% and 33% previously receiving omalizumab, respectively. In MENSA, mepolizumab reduced the rate of exacerbations by 57% (prior omalizumab) and 47% (no prior omalizumab) vs placebo. In SIRIUS, reductions in OCS use were comparable regardless of prior omalizumab use. Despite reducing chronic OCS use, mepolizumab also resulted in similar reductions in exacerbation rate relative to placebo in both subgroups. Asthma control and quality of life improved with mepolizumab vs placebo in both studies independent of prior omalizumab use, as shown by ACQ-5 and SGRQ scores. Adverse events were also comparable irrespective of prior omalizumab use. These post hoc analyses indicate that patients with severe eosinophilic asthma respond positively to mepolizumab regardless of prior use of omalizumab. © 2016 The Authors. Allergy Published by John Wiley & Sons Ltd.

PERFORMANCE-BASED CONTRACTING IN CONSTRUCTION PHASE AND MAINTENANCE PHASE OF PAVEMENT

Science.gov (United States)

Yoshida, Takeshi

Performance-based contracting for pavement in Japan started as performance warranties in construction phase, in 1999. Recently, road agencies have recognized the applicability of this type of contracting in outsourcing of maintenance activities. The objectives of this study are to clarify the issues of performance specifying in construction phase and maintenance phase of pavement, and to propose measures to be taken. This paper, with the recognition that the life of each pavement depends on performance standards for various attributes, reviews domestic and foreign examples of performance-based contracting. A performance standard based on the average of current practices can enhance product quality and service life with a warranty contract. Repair thresholds and response time for each deficiency should be considered as performance standards in maintenance phase.

Mechanical modulation method for ultrasensitive phase measurements in photonics biosensing.

Science.gov (United States)

Patskovsky, S; Maisonneuve, M; Meunier, M; Kabashin, A V

2008-12-22

A novel polarimetry methodology for phase-sensitive measurements in single reflection geometry is proposed for applications in optical transduction-based biological sensing. The methodology uses altering step-like chopper-based mechanical phase modulation for orthogonal s- and p- polarizations of light reflected from the sensing interface and the extraction of phase information at different harmonics of the modulation. We show that even under a relatively simple experimental arrangement, the methodology provides the resolution of phase measurements as low as 0.007 deg. We also examine the proposed approach using Total Internal Reflection (TIR) and Surface Plasmon Resonance (SPR) geometries. For TIR geometry, the response appears to be strongly dependent on the prism material with the best values for high refractive index Si. The detection limit for Si-based TIR is estimated as 10(-5) in terms Refractive Index Units (RIU) change. SPR geometry offers much stronger phase response due to a much sharper phase characteristics. With the detection limit of 3.2*10(-7) RIU, the proposed methodology provides one of best sensitivities for phase-sensitive SPR devices. Advantages of the proposed method include high sensitivity, simplicity of experimental setup and noise immunity as a result of a high stability modulation.

Sensitivity analysis of a complex, proposed geologic waste disposal system using the Fourier Amplitude Sensitivity Test method

International Nuclear Information System (INIS)

Lu Yichi; Mohanty, Sitakanta

2001-01-01

The Fourier Amplitude Sensitivity Test (FAST) method has been used to perform a sensitivity analysis of a computer model developed for conducting total system performance assessment of the proposed high-level nuclear waste repository at Yucca Mountain, Nevada, USA. The computer model has a large number of random input parameters with assigned probability density functions, which may or may not be uniform, for representing data uncertainty. The FAST method, which was previously applied to models with parameters represented by the uniform probability distribution function only, has been modified to be applied to models with nonuniform probability distribution functions. Using an example problem with a small input parameter set, several aspects of the FAST method, such as the effects of integer frequency sets and random phase shifts in the functional transformations, and the number of discrete sampling points (equivalent to the number of model executions) on the ranking of the input parameters have been investigated. Because the number of input parameters of the computer model under investigation is too large to be handled by the FAST method, less important input parameters were first screened out using the Morris method. The FAST method was then used to rank the remaining parameters. The validity of the parameter ranking by the FAST method was verified using the conditional complementary cumulative distribution function (CCDF) of the output. The CCDF results revealed that the introduction of random phase shifts into the functional transformations, proposed by previous investigators to disrupt the repetitiveness of search curves, does not necessarily improve the sensitivity analysis results because it destroys the orthogonality of the trigonometric functions, which is required for Fourier analysis

Thermodynamics of phase transitions

International Nuclear Information System (INIS)

Cofta, H.

1972-01-01

The phenomenology of the phase transitions has been considered. The definitions of thermodynamic functions and parameters, as well as those of the phase transitions, are given and some of the relations between those quantities are discussed. The phase transitions classification proposed by Ehrenfest has been described. The most important features of phase transitions are discussed using the selected physical examples including the critical behaviour of ferromagnetic materials at the Curie temperature and antiferromagnetic materials at the Neel temperature. Some aspects of the Ehrenfest's equations, that have been derived, for the interfacial lines and surfaces are considered as well as the role the notion of interfaces. (S.B.)

The Genealogical Tree of Ethanol: Gas-phase Formation of Glycolaldehyde, Acetic Acid, and Formic Acid

Science.gov (United States)

Skouteris, Dimitrios; Balucani, Nadia; Ceccarelli, Cecilia; Vazart, Fanny; Puzzarini, Cristina; Barone, Vincenzo; Codella, Claudio; Lefloch, Bertrand

2018-02-01

Despite the harsh conditions of the interstellar medium, chemistry thrives in it, especially in star-forming regions where several interstellar complex organic molecules (iCOMs) have been detected. Yet, how these species are synthesized is a mystery. The majority of current models claim that this happens on interstellar grain surfaces. Nevertheless, evidence is mounting that neutral gas-phase chemistry plays an important role. In this paper, we propose a new scheme for the gas-phase synthesis of glycolaldehyde, a species with a prebiotic potential and for which no gas-phase formation route was previously known. In the proposed scheme, the ancestor is ethanol and the glycolaldehyde sister species are acetic acid (another iCOM with unknown gas-phase formation routes) and formic acid. For the reactions of the new scheme with no available data, we have performed electronic structure and kinetics calculations deriving rate coefficients and branching ratios. Furthermore, after a careful review of the chemistry literature, we revised the available chemical networks, adding and correcting several reactions related to glycolaldehyde, acetic acid, and formic acid. The new chemical network has been used in an astrochemical model to predict the abundance of glycolaldehyde, acetic acid, and formic acid. The predicted abundance of glycolaldehyde depends on the ethanol abundance in the gas phase and is in excellent agreement with the measured one in hot corinos and shock sites. Our new model overpredicts the abundance of acetic acid and formic acid by about a factor of 10, which might imply a yet incomplete reaction network.

A Unified Impedance Model of Voltage-Source Converters with Phase-Locked Loop Effect

DEFF Research Database (Denmark)

Wang, Xiongfei; Harnefors, Lennart; Blaabjerg, Frede

2016-01-01

This paper proposes a unified impedance model for analyzing the effect of Phase-Locked Loop (PLL) on the stability of grid-connected voltage-source converters. In the approach, the dq-frame impedance model is transformed into the stationary αβ-frame by means of complex transfer functions...... and complex space vectors, which not only predicts the stability impact of the PLL, but reveals also its frequency coupling effect in the phase domain. Thus, the impedance models previously developed in the different domains can be unified. Moreover, the impedance shaping effects of PLL are structurally...... characterized for the current control in the rotating dq-frame and the stationary αβ-frame. Case studies based on the unified impedance model are presented, which are then verified in the time-domain simulations and experiments. The results closely correlate with the impedance-based analysis....

Optical image encryption with silhouette removal based on interference and phase blend processing

Science.gov (United States)

Wang, Qu

2012-10-01

To completely eliminate the silhouette problem that inherently exists in the earlier interference-based encryption scheme with two phase-only masks (POMs), we propose a simple new encryption method based on optical interference of one random POM and two analytically obtained POMs. Different from the previous methods which require time-consuming iterative computation or postprocessing of the POMs for silhouette removal, our method can resolve the problem during the production of the POMs based on interference principle. Information associated with the original image is smoothed away by modulation of the random POM. Illegal deciphers cannot retrieve the primitive image using only one or two of the POMs. Incorporated with the linear phase blend operation, our method can provide higher robustness against brute force attacks. Simulation results are presented to support the validity and feasibility of our method.

Electric vehicles batteries thermal management systems employing phase change materials

Science.gov (United States)

Ianniciello, Lucia; Biwolé, Pascal Henry; Achard, Patrick

2018-02-01

Battery thermal management is necessary for electric vehicles (EVs), especially for Li-ion batteries, due to the heat dissipation effects on those batteries. Usually, air or coolant circuits are employed as thermal management systems in Li-ion batteries. However, those systems are expensive in terms of investment and operating costs. Phase change materials (PCMs) may represent an alternative which could be cheaper and easier to operate. In fact, PCMs can be used as passive or semi-passive systems, enabling the global system to sustain near-autonomous operations. This article presents the previous developments introducing PCMs for EVs battery cooling. Different systems are reviewed and solutions are proposed to enhance PCMs efficiency in those systems.

Computing optimal interfacial structure of modulated phases

OpenAIRE

Xu, Jie; Wang, Chu; Shi, An-Chang; Zhang, Pingwen

2016-01-01

We propose a general framework of computing interfacial structures between two modulated phases. Specifically we propose to use a computational box consisting of two half spaces, each occupied by a modulated phase with given position and orientation. The boundary conditions and basis functions are chosen to be commensurate with the bulk structures. It is observed that the ordered nature of modulated structures stabilizes the interface, which enables us to obtain optimal interfacial structures...

Proposals for the solution of the phase problem in electron microscopy

International Nuclear Information System (INIS)

Toorn, P. van.

1979-01-01

This thesis discusses the phase problem in electron microscopy, i.e. the determination of the unknown complex wave function in the image plane or in the exit pupil from the measured intensity distributions in both planes. The calculation of the wave function is the first problem to be solved for the determination of the object structure from electron micrographs. (Auth.)

Modelling gas migration in compacted bentonite: gambit club phase 3. Final report

International Nuclear Information System (INIS)

Hoch, A.R.; Cliffe, K.A.; Swift, B.T.; Rodwell, W.R.

2004-04-01

This report describes the third phase of a programme of work to develop a computational model of gas migration through highly compacted water-saturated bentonite. One difficulty with this endeavour is the definitive determination of the mechanism of the gas migration from the available experimental data. The report contains a brief review of the experimental data and their interpretation. The model development work reported involves the investigation of two ways of enhancing a model proposed in the previous phase of the programme. This model was based on the concept that gas migration pathways were created by consolidating the clay fabric by application of gas pressure to create porosity through which the gas could flow. The two developments of this model that are separately explored in this work are: (a) The incorporation of a proper treatment of the stress-strain behaviour of the clay in (b) response to gas migration. The previous model had only considered stress effects through simple volume changes to the clay fabric. The inclusion of a dual-porosity feature into the model in an attempt to address the role that the clay fabric might play in gas migration through the clay, in particular the role that pre-existing interstack voids might have in gas migration. The consideration of hysteresis effects was also included in this study. As in previous GAMBIT Club work, the models are tested against the results of laboratory experiments. (orig.)

Improvement of the accuracy of phase observation by modification of phase-shifting electron holography

International Nuclear Information System (INIS)

Suzuki, Takahiro; Aizawa, Shinji; Tanigaki, Toshiaki; Ota, Keishin; Matsuda, Tsuyoshi; Tonomura, Akira

2012-01-01

We found that the accuracy of the phase observation in phase-shifting electron holography is strongly restricted by time variations of mean intensity and contrast of the holograms. A modified method was developed for correcting these variations. Experimental results demonstrated that the modification enabled us to acquire a large number of holograms, and as a result, the accuracy of the phase observation has been improved by a factor of 5. -- Highlights: ► A modified phase-shifting electron holography was proposed. ► The time variation of mean intensity and contrast of holograms were corrected. ► These corrections lead to a great improvement of the resultant phase accuracy. ► A phase accuracy of about 1/4000 rad was achieved from experimental results.

Reactions between Ti3Al-Nb and mixed second phases

International Nuclear Information System (INIS)

Bowden, D.M.; Sastry, S.M.L.; Smith, P.R.

1989-01-01

In engineered multiphase materials, the interfacial characteristics that develop between individual phases during high-temperature exposure can play a significant role in determining mechanical behavior. In titanium alloys containing silicon carbide and boron fibers, rule-of-mixtures strength values are not realized, primarily because of the chemical reactions that occur between the matrix alloys and these phases. Previous investigations of the reaction between titanium alloys and boron have shown that a uniform reaction layer of the phase TiB 2 is formed, followed by growth of TiB needles. The primary mechanism of this reaction was observed to be the one-way diffusion of boron into titanium. The use of a B 4 C coating on the boron (B 4 C/B) as a diffusion barrier was found to significantly slow the reaction between the titanium and boron. Certain alloy additions to titanium, such as aluminum, vanadium, and molybdenum, can increase the chemical compatibility of these two phases. For the case of SiC, the reaction zone is formed by the interdiffusion of silicon and carbon atoms with titanium. X-ray diffraction studies have shown the reaction components to include TiC, Ti 5 Si 3 , and TiSi 2 . In the present study, the reactions between a Ti 3 Al alloy and both B 4 C/B and SiC have been examined. Reaction models are proposed to describe the development of the chemical interaction zone formed between these phases

Simulation of bulk phases formed by polyphilic liquid crystal dendrimers

Directory of Open Access Journals (Sweden)

J.M. Ilnytskyi

2010-01-01

Full Text Available A coarse-grained simulation model for a third generation liquid crystalline dendrimer (LCDr is presented. It allows, for the first time, for a successful molecular simulation study of a relation between the shape of a polyphilic macromolecular mesogen and the symmetry of a macroscopic phase. The model dendrimer consists of a soft central sphere and 32 grafted chains each terminated by a mesogen group. The mesogenic pair interactions are modelled by the recently proposed soft core spherocylinder model of Lintuvuori and Wilson [J. Chem. Phys, 128, 044906, (2008]. Coarse-grained (CG molecular dynamics (MD simulations are performed on a melt of 100 molecules in the anisotropic-isobaric ensemble. The model LCDr shows conformational bistability, with both rod-like and disc-like conformations stable at lower temperatures. Each conformation can be induced by an external aligning field of appropriate symmetry that acts on the mesogens (uniaxial for rod-like and planar for disc-like, leading to formation of a monodomain smectic A (SmA or a columnar (Col phase, respectively. Both phases are stable for approximately the same temperature range and both exhibit a sharp transition to an isotropic cubic-like phase upon heating. We observe a very strong coupling between the conformation of the LCDr and the symmetry of a bulk phase, as suggested previously by theory. The study reveals rich potential in terms of the application of this form of CG modelling to the study of molecular self-assembly of liquid crystalline macromolecules.

Deterministic nonlinear phase gates induced by a single qubit

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Park, Kimin; Marek, Petr; Filip, Radim

2018-05-01

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

Identification of emission sources of umbral flashes using phase congruency

International Nuclear Information System (INIS)

Feng Song; Yang Yun-Fei; Ji Kai-Fan; Yu Lan

2014-01-01

The emission sources of umbral flashes (UFs) are believed to be closely related to running umbral and penumbral waves, and are concluded to be associated with umbral dots in the solar photosphere. Accurate identification of emission sources of UFs is crucial for investigating these physical phenomena and their inherent relationships. A relatively novel model of shape perception, namely phase congruency (PC), uses phase information in the Fourier domain to identify the geometrical shape of the region of interest in different intensity levels, rather than intensity or gradient. Previous studies indicate that the model is suitable for identifying features with low contrast and low luminance. In the present paper, we applied the PC model to identify the emission sources of UFs and to locate their positions. For illustrating the high performance of our proposed method, two time sequences of Ca II H images derived from the Hinode/SOT on 2010 August 10 and 2013 August 20 were used. Furthermore, we also compared these results with the analysis results that are identified by the traditional/classical identification methods, including the gray-scale adjusted technique and the running difference technique. The result of our analysis demonstrates that our proposed method is more accurate and effective than the traditional identification methods when applied to identifying the emission sources of UFs and to locating their positions. (research papers)

Suppression of laser phase noise in direct-detection optical OFDM transmission using phase-conjugated pilots

Science.gov (United States)

Zhang, Lu; Ming, Yi; Li, Jin

2017-11-01

Due to the unique phase noise (PN) characteristics in direct-detection optical OFDM (DDO-OFDM) systems, the design of PN compensator is considered as a difficult task. In this paper, a laser PN suppression scheme with low complexity for DDO-OFDM based on coherent superposition of data carrying subcarriers and their phase conjugates is proposed. Through theoretical derivation, the obvious PN suppression is observed. The effectiveness of this technique is demonstrated by simulation of a 4-QAM DDO-OFDM system over 1000 km transmission length at different laser line-width and subcarrier frequency spacing. The results show that the proposed scheme can significantly suppress both varied phase rotation term (PTR) and inter-carrier interference (ICI), and the laser line-width can be relaxed with up to 9 dB OSNR saving or even breakthrough of performance floor.

An alternative approach in operator allocation labor intensive manufacturing system: A three-phase methodology framework

Science.gov (United States)

Mat Rani, Ruzanita; Ismail, Wan Rosmanira

2013-04-01

Operator allocation is one of the most important decisions that can affect productivity in labor-intensive manufacturing system. Improper decision on operator allocation will reduce company's throughput and increase waste. Therefore, all factors such as operators' performance and operational constraints need to be considered in making the best operator allocation decision. Most of previous studies used two phases methodology. In two phases methodology, they used operational constraints and treated all operators to have the same level of performance for making decision on operator allocation. Therefore, in this paper a three-phase methodology is proposed to determine the optimal operator allocation. This methodology advances the existing approach on operator allocation by combining operators' performance and operational constraints. The methodology starts with evaluating the operators' performance. Then, it is followed with determining inputs and outputs for operator allocation alternatives and it ends with determining the optimal operator allocation. This paper will give ideas and directions to the management of the manufacturing company in determining the optimal operator allocation decision.

A Phase-Adaptive Garbage Collector Using Dynamic Heap Partitioning and Opportunistic Collection

Science.gov (United States)

Roh, Yangwoo; Kim, Jaesub; Park, Kyu Ho

Applications usually have their own phases in heap memory usage. The traditional garbage collector fails to match various application phases because the same heuristic on the object behavior is used throughout the entire execution. This paper introduces a phase-adaptive garbage collector which reorganizes the heap layout and adjusts the invocation time of the garbage collection according to the phases. The proposed collector identifies phases by detecting the application methods strongly related to the phase boundaries. The experimental results show that the proposed phase-adaptive collector successfully recognizes application phases and improves the garbage collection time by as much as 41%.

Examination and modeling of void growth kinetics in modern high strength dual phase steels during uniaxial tensile deformation

Energy Technology Data Exchange (ETDEWEB)

Saeidi, N., E-mail: navidsae@gmail.com [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Ashrafizadeh, F.; Niroumand, B. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Forouzan, M.R.; Mohseni mofidi, S. [Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Barlat, F. [Materials Mechanics Laboratory (MML), Graduate Institute of Ferrous Technology (GIFT), Pohang University of Science and Technology - POSTECH, San 31 Hyoja-dong, Nam-gu, Pohang, Gyeongbuk 790-784 (Korea, Republic of)

2016-04-01

Ductile fracture mechanisms during uniaxial tensile testing of two different modern high strength dual phase steels, i.e. DP780 and DP980, were studied. Detailed microstructural characterization of the strained and sectioned samples was performed by scanning electron microscopy as well as EBSD examination. The results revealed that interface decohesion, especially at martensite particles located at ferrite grain boundaries, was the most probable mechanism for void nucleation. It was also revealed that the creation of cellular substructure can reduce stored strain energy and thereby, higher true fracture strain was obtained in DP980 than DP780 steel. Prediction of void growth behavior based on some previously proposed models showed unreliable results. Therefore, a modified model based on Rice-Tracey family models was proposed which showed a very lower prediction error compared with other models. - Highlights: • Damage mechanism in two modern high strength dual phase steels was studied. • Creation of cellular substructures can reduce the stored strain energy within the ferrite grains. • The experimental values were examined by Agrawal as well as RT family models. • A modified model was proposed for prediction of void growth behavior of DP steels.

Reversed Phase Column HPLC-ICP-MS Conditions for Arsenic Speciation Analysis of Rice Flour.

Science.gov (United States)

Narukawa, Tomohiro; Matsumoto, Eri; Nishimura, Tsutomu; Hioki, Akiharu

2015-01-01

New measurement conditions for arsenic speciation analysis of rice flour were developed using HPLC-ICP-MS equipped with a reversed phase ODS column. Eight arsenic species, namely, arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid (MMAA), dimethylarsinic acid (DMAA), trimethylarsine oxide (TMAO), tetramethylarsonium (TeMA), arsenobetaine (AsB) and arsenocholine (AsC), were separated and determined under the proposed conditions. In particular, As(III) and MMAA and DMAA and AsB were completely separated using a newly proposed eluent containing ammonium dihydrogen phosphate. Importantly, the sensitivity changes, in particular those of As(V) and As(III) caused by coexisting elements and by complex matrix composition, which had been problematical in previously reported methods, were eliminated. The new eluent can be applied to C8, C18 and C30 ODS columns with the same effectiveness and with excellent repeatability. The proposed analytical method was successfully applied to extracts of rice flour certified reference materials.

Phase-Image Encryption Based on 3D-Lorenz Chaotic System and Double Random Phase Encoding

Science.gov (United States)

Sharma, Neha; Saini, Indu; Yadav, AK; Singh, Phool

2017-12-01

In this paper, an encryption scheme for phase-images based on 3D-Lorenz chaotic system in Fourier domain under the 4f optical system is presented. The encryption scheme uses a random amplitude mask in the spatial domain and a random phase mask in the frequency domain. Its inputs are phase-images, which are relatively more secure as compared to the intensity images because of non-linearity. The proposed scheme further derives its strength from the use of 3D-Lorenz transform in the frequency domain. Although the experimental setup for optical realization of the proposed scheme has been provided, the results presented here are based on simulations on MATLAB. It has been validated for grayscale images, and is found to be sensitive to the encryption parameters of the Lorenz system. The attacks analysis shows that the key-space is large enough to resist brute-force attack, and the scheme is also resistant to the noise and occlusion attacks. Statistical analysis and the analysis based on correlation distribution of adjacent pixels have been performed to test the efficacy of the encryption scheme. The results have indicated that the proposed encryption scheme possesses a high level of security.

A Novel Concept for Three-Phase Cascaded Multilevel Inverter Topologies

Directory of Open Access Journals (Sweden)

Md Mubashwar Hasan

2018-01-01

Full Text Available One of the key challenges in multilevel inverters (MLIs design is to reduce the number of components used in the implementation while maximising the number of output voltage levels. This paper proposes a new concept that facilitates a device count reduction technique of existing cascaded MLIs. Moreover, the proposed concept can be utilised to extend existing single phase cascaded MLI topologies to three-phase structure without tripling the number of semiconductor components and input dc-supplies as per the current practice. The new generalized concept involves two stages; namely, cascaded stage and phase generator stage. The phase generator stage is a combination of a conventional three-phase two level inverter and three bi-directional switches while the cascaded stage can employ any existing cascaded topology. A laboratory prototype model is built and extensive experimental analyses are conducted to validate the feasibility of the proposed cascaded MLI concept.

Recurrence phase shift in Fermi-Pasta-Ulam nonlinear dynamics

Energy Technology Data Exchange (ETDEWEB)

Devine, N., E-mail: nnd124@rsphysse.anu.edu.au [Optical Sciences Group, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia); Ankiewicz, A. [Optical Sciences Group, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia); Genty, G. [Tampere University of Technology, Optics Laboratory, FI-33101 Tampere (Finland); Dudley, J.M. [Institut FEMTO-ST UMR 6174 CNRS/Universite de Franche-Comte, Besancon (France); Akhmediev, N. [Optical Sciences Group, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia)

2011-11-07

We show that the dynamics of Fermi-Pasta-Ulam recurrence is associated with a nonlinear phase shift between initial and final states that are otherwise identical, after a full growth-return cycle. The properties of this phase shift are studied for the particular case of the self-focussing nonlinear Schroedinger equation, and we describe the magnitude of the phase shift in terms of the system parameters. This phase shift, accumulated during the nonlinear recurrence cycle, is a previously-unremarked feature of the Fermi-Pasta-Ulam problem, and we anticipate its wide significance as an essential feature of related dynamics in other systems. -- Highlights: → The dynamics of FPU recurrence is associated with a phase shift between initial and final states. → The properties of this phase shift are studied for the self-focussing NLS equation. → This phase shift is a previously-unremarked feature of the FPU growth-return cycle. → We anticipate its wide significance as an essential feature of related dynamics in other systems.

Recurrence phase shift in Fermi-Pasta-Ulam nonlinear dynamics

International Nuclear Information System (INIS)

Devine, N.; Ankiewicz, A.; Genty, G.; Dudley, J.M.; Akhmediev, N.

2011-01-01

We show that the dynamics of Fermi-Pasta-Ulam recurrence is associated with a nonlinear phase shift between initial and final states that are otherwise identical, after a full growth-return cycle. The properties of this phase shift are studied for the particular case of the self-focussing nonlinear Schroedinger equation, and we describe the magnitude of the phase shift in terms of the system parameters. This phase shift, accumulated during the nonlinear recurrence cycle, is a previously-unremarked feature of the Fermi-Pasta-Ulam problem, and we anticipate its wide significance as an essential feature of related dynamics in other systems. -- Highlights: → The dynamics of FPU recurrence is associated with a phase shift between initial and final states. → The properties of this phase shift are studied for the self-focussing NLS equation. → This phase shift is a previously-unremarked feature of the FPU growth-return cycle. → We anticipate its wide significance as an essential feature of related dynamics in other systems.

Nonlinear observer based phase synchronization of chaotic systems

International Nuclear Information System (INIS)

Meng Juan; Wang Xingyuan

2007-01-01

This Letter analyzes the phase synchronization problem of autonomous chaotic systems. Based on the nonlinear state observer algorithm and the pole placement technique, a phase synchronization scheme is designed. The phase synchronization of a new chaotic system is achieved by using this observer controller. Numerical simulations further demonstrate the effectiveness of the proposed phase synchronization scheme

Improvement of the accuracy of phase observation by modification of phase-shifting electron holography

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Takahiro; Aizawa, Shinji; Tanigaki, Toshiaki [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Ota, Keishin, E-mail: ota@microphase.co.jp [Microphase Co., Ltd., Onigakubo 1147-9, Tsukuba, Ibaragi 300-2651 (Japan); Matsuda, Tsuyoshi [Japan Science and Technology Agency, Kawaguchi-shi, Saitama 332-0012 (Japan); Tonomura, Akira [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Okinawa Institute of Science and Technology, Graduate University, Kunigami, Okinawa 904-0495 (Japan); Central Research Laboratory, Hitachi, Ltd., Hatoyama, Saitama 350-0395 (Japan)

2012-07-15

We found that the accuracy of the phase observation in phase-shifting electron holography is strongly restricted by time variations of mean intensity and contrast of the holograms. A modified method was developed for correcting these variations. Experimental results demonstrated that the modification enabled us to acquire a large number of holograms, and as a result, the accuracy of the phase observation has been improved by a factor of 5. -- Highlights: Black-Right-Pointing-Pointer A modified phase-shifting electron holography was proposed. Black-Right-Pointing-Pointer The time variation of mean intensity and contrast of holograms were corrected. Black-Right-Pointing-Pointer These corrections lead to a great improvement of the resultant phase accuracy. Black-Right-Pointing-Pointer A phase accuracy of about 1/4000 rad was achieved from experimental results.

Continuous-Scan Phased Array Measurement Methods for Turbofan Engine Acoustic Testing, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — ATA Engineering, Inc., (ATA) proposes an SBIR project to advance the technology readiness level (TRL) of a method for measuring phased array acoustic data for...

Same-strand overlapping genes in bacteria: compositional determinants of phase bias

Directory of Open Access Journals (Sweden)

Landan Giddy

2008-08-01

Full Text Available Abstract Background Same-strand overlapping genes may occur in frameshifts of one (phase 1 or two nucleotides (phase 2. In previous studies of bacterial genomes, long phase-1 overlaps were found to be more numerous than long phase-2 overlaps. This bias was explained by either genomic location or an unspecified selection advantage. Models that focused on the ability of the two genes to evolve independently did not predict this phase bias. Here, we propose that a purely compositional model explains the phase bias in a more parsimonious manner. Same-strand overlapping genes may arise through either a mutation at the termination codon of the upstream gene or a mutation at the initiation codon of the downstream gene. We hypothesized that given these two scenarios, the frequencies of initiation and termination codons in the two phases may determine the number for overlapping genes. Results We examined the frequencies of initiation- and termination-codons in the two phases, and found that termination codons do not significantly differ between the two phases, whereas initiation codons are more abundant in phase 1. We found that the primary factors explaining the phase inequality are the frequencies of amino acids whose codons may combine to form start codons in the two phases. We show that the frequencies of start codons in each of the two phases, and, hence, the potential for the creation of overlapping genes, are determined by a universal amino-acid frequency and species-specific codon usage, leading to a correlation between long phase-1 overlaps and genomic GC content. Conclusion Our model explains the phase bias in same-strand overlapping genes by compositional factors without invoking selection. Therefore, it can be used as a null model of neutral evolution to test selection hypotheses concerning the evolution of overlapping genes. Reviewers This article was reviewed by Bill Martin, Itai Yanai, and Mikhail Gelfand.

Wide gap Chern Mott insulating phases achieved by design

Science.gov (United States)

Guo, Hongli; Gangopadhyay, Shruba; Köksal, Okan; Pentcheva, Rossitza; Pickett, Warren E.

2017-12-01

Quantum anomalous Hall insulators, which display robust boundary charge and spin currents categorized in terms of a bulk topological invariant known as the Chern number (Thouless et al Phys. Rev. Lett. 49, 405-408 (1982)), provide the quantum Hall anomalous effect without an applied magnetic field. Chern insulators are attracting interest both as a novel electronic phase and for their novel and potentially useful boundary charge and spin currents. Honeycomb lattice systems such as we discuss here, occupied by heavy transition-metal ions, have been proposed as Chern insulators, but finding a concrete example has been challenging due to an assortment of broken symmetry phases that thwart the topological character. Building on accumulated knowledge of the behavior of the 3d series, we tune spin-orbit and interaction strength together with strain to design two Chern insulator systems with bandgaps up to 130 meV and Chern numbers C = -1 and C = 2. We find, in this class, that a trade-off between larger spin-orbit coupling and strong interactions leads to a larger gap, whereas the stronger spin-orbit coupling correlates with the larger magnitude of the Hall conductivity. Symmetry lowering in the course of structural relaxation hampers obtaining quantum anomalous Hall character, as pointed out previously; there is only mild structural symmetry breaking of the bilayer in these robust Chern phases. Recent growth of insulating, magnetic phases in closely related materials with this orientation supports the likelihood that synthesis and exploitation will follow.

Estimating disease prevalence from two-phase surveys with non-response at the second phase

Science.gov (United States)

Gao, Sujuan; Hui, Siu L.; Hall, Kathleen S.; Hendrie, Hugh C.

2010-01-01

SUMMARY In this paper we compare several methods for estimating population disease prevalence from data collected by two-phase sampling when there is non-response at the second phase. The traditional weighting type estimator requires the missing completely at random assumption and may yield biased estimates if the assumption does not hold. We review two approaches and propose one new approach to adjust for non-response assuming that the non-response depends on a set of covariates collected at the first phase: an adjusted weighting type estimator using estimated response probability from a response model; a modelling type estimator using predicted disease probability from a disease model; and a regression type estimator combining the adjusted weighting type estimator and the modelling type estimator. These estimators are illustrated using data from an Alzheimer’s disease study in two populations. Simulation results are presented to investigate the performances of the proposed estimators under various situations. PMID:10931514

Design of Phase II Non-inferiority Trials.

Science.gov (United States)

Jung, Sin-Ho

2017-09-01

With the development of inexpensive treatment regimens and less invasive surgical procedures, we are confronted with non-inferiority study objectives. A non-inferiority phase III trial requires a roughly four times larger sample size than that of a similar standard superiority trial. Because of the large required sample size, we often face feasibility issues to open a non-inferiority trial. Furthermore, due to lack of phase II non-inferiority trial design methods, we do not have an opportunity to investigate the efficacy of the experimental therapy through a phase II trial. As a result, we often fail to open a non-inferiority phase III trial and a large number of non-inferiority clinical questions still remain unanswered. In this paper, we want to develop some designs for non-inferiority randomized phase II trials with feasible sample sizes. At first, we review a design method for non-inferiority phase III trials. Subsequently, we propose three different designs for non-inferiority phase II trials that can be used under different settings. Each method is demonstrated with examples. Each of the proposed design methods is shown to require a reasonable sample size for non-inferiority phase II trials. The three different non-inferiority phase II trial designs are used under different settings, but require similar sample sizes that are typical for phase II trials.

Probabilistic Q-function distributions in fermionic phase-space

International Nuclear Information System (INIS)

Rosales-Zárate, Laura E C; Drummond, P D

2015-01-01

We obtain a positive probability distribution or Q-function for an arbitrary fermionic many-body system. This is different to previous Q-function proposals, which were either restricted to a subspace of the overall Hilbert space, or used Grassmann methods that do not give probabilities. The fermionic Q-function obtained here is constructed using normally ordered Gaussian operators, which include both non-interacting thermal density matrices and BCS states. We prove that the Q-function exists for any density matrix, is real and positive, and has moments that correspond to Fermi operator moments. It is defined on a finite symmetric phase-space equivalent to the space of real, antisymmetric matrices. This has the natural SO(2M) symmetry expected for Majorana fermion operators. We show that there is a physical interpretation of the Q-function: it is the relative probability for observing a given Gaussian density matrix. The distribution has a uniform probability across the space at infinite temperature, while for pure states it has a maximum value on the phase-space boundary. The advantage of probabilistic representations is that they can be used for computational sampling without a sign problem. (fast track communication)

Monte Carlo Solutions for Blind Phase Noise Estimation

Directory of Open Access Journals (Sweden)

Çırpan Hakan

2009-01-01

Full Text Available This paper investigates the use of Monte Carlo sampling methods for phase noise estimation on additive white Gaussian noise (AWGN channels. The main contributions of the paper are (i the development of a Monte Carlo framework for phase noise estimation, with special attention to sequential importance sampling and Rao-Blackwellization, (ii the interpretation of existing Monte Carlo solutions within this generic framework, and (iii the derivation of a novel phase noise estimator. Contrary to the ad hoc phase noise estimators that have been proposed in the past, the estimators considered in this paper are derived from solid probabilistic and performance-determining arguments. Computer simulations demonstrate that, on one hand, the Monte Carlo phase noise estimators outperform the existing estimators and, on the other hand, our newly proposed solution exhibits a lower complexity than the existing Monte Carlo solutions.

Belotecan/cisplatin versus etoposide/cisplatin in previously untreated patients with extensive-stage small cell lung carcinoma: a multi-center randomized phase III trial

International Nuclear Information System (INIS)

Oh, In-Jae; Kim, Kyu-Sik; Park, Cheol-Kyu; Kim, Young-Chul; Lee, Kwan-Ho; Jeong, Jin-Hong; Kim, Sun-Young; Lee, Jeong-Eun; Shin, Kye-Chul; Jang, Tae-Won; Lee, Hyun-Kyung; Lee, Kye-Young; Lee, Sung-Yong

2016-01-01

No novel chemotherapeutic combinations have demonstrated superior efficacy to etoposide/cisplatin (EP), a standard treatment regimen for extensive-stage small cell lung carcinoma (ES-SCLC) over the past decade. We aimed to compare the efficacy and safety of belotecan/cisplatin (BP) and EP regimens in chemotherapy- and radiotherapy-naïve patients with previously untreated ES-SCLC. We conducted a multi-center, randomized, open-label, parallel-group, phase III clinical study. A total of 157 patients were recruited at 14 centers with 147 patients meeting the inclusion/exclusion criteria and randomized to either BP (n = 71) or EP (n = 76) treatment arms. A non-inferior response rate (RR) in the BP arm, analyzed by intent-to-treat analysis according to Response Evaluation Criteria in Solid Tumors version 1.0 criteria, was used as the primary endpoint. The secondary endpoints were progression-free survival (PFS) and overall survival (OS). In the BP arm, one patient had a complete response, 41 had a partial response (PR), and 17 had stable disease (SD). In the EP arm, 35 patients had PR and 28 had SD. The RR in the BP arm was non-inferior to the EP regimen in patients with ES-SCLC (BP: 59.2 %, EP: 46.1 %, difference: 13.1 %, 90 % two-sided confidence interval: -0.3–26.5, meeting the predefined non-inferiority criterion of -15.0 %). No significant differences in OS or PFS were observed between the treatment arms. Hematologic toxicities, including grade 3/4 anemia and thrombocytopenia, were significantly more prevalent in the BP arm than the EP arm. The RR to the BP regimen was non-inferior to the EP regimen in chemotherapy- and radiotherapy-naïve patients with previously untreated ES-SCLC. Hematologic toxicities were significantly more prevalent in the BP group, indicating that BP should be used with care, particularly in patients with a poor performance status. Further studies assessing PFS and OS are required to validate the superiority of the BP regimen. Clinical

Optical image transformation and encryption by phase-retrieval-based double random-phase encoding and compressive ghost imaging

Science.gov (United States)

Yuan, Sheng; Yang, Yangrui; Liu, Xuemei; Zhou, Xin; Wei, Zhenzhuo

2018-01-01

An optical image transformation and encryption scheme is proposed based on double random-phase encoding (DRPE) and compressive ghost imaging (CGI) techniques. In this scheme, a secret image is first transformed into a binary image with the phase-retrieval-based DRPE technique, and then encoded by a series of random amplitude patterns according to the ghost imaging (GI) principle. Compressive sensing, corrosion and expansion operations are implemented to retrieve the secret image in the decryption process. This encryption scheme takes the advantage of complementary capabilities offered by the phase-retrieval-based DRPE and GI-based encryption techniques. That is the phase-retrieval-based DRPE is used to overcome the blurring defect of the decrypted image in the GI-based encryption, and the CGI not only reduces the data amount of the ciphertext, but also enhances the security of DRPE. Computer simulation results are presented to verify the performance of the proposed encryption scheme.

Improved Metal-Polymeric Laminate Radiation Shielding, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — In this proposed Phase II program, builds on the phase I feaibility where a multifunctional lightweight radiation shield composite was developed and fabricated. This...

Phased Startup Initiative Phases 3 and 4 Test Plan and Test Specification (OCRWM)

International Nuclear Information System (INIS)

PITNER, A.L.

2000-01-01

Construction for the Spent Nuclear Fuel (SNF) Project facilities is continuing per the Level III Baseline Schedule, and installation of the Fuel Retrieval System (FRS) and Integrated Water Treatment System (IWTS) in K West Basin is now complete. In order to accelerate the project, a phased start up strategy to initiate testing of the FRS and IWTS early in the overall project schedule was proposed (Williams 1999). Wilkinson (1999) expands the definition of the original proposal into four functional testing phases of the Phased Startup Initiative (PSI). Phases 1 and 2 are based on performing functional tests using dummy fuel. These tests are described in separate planning documents. This test plan provides overall guidance for Phase 3 and 4 tests, which are performed using actual irradiated N fuel assemblies. The overall objective of the Phase 3 and 4 testing is to verify how the FRS and IWTS respond while processing actual fuel. Conducting these tests early in the project schedule will allow identification and resolution of equipment and process problems before they become activities on the start-up critical path. The specific objectives of this test plan are to: (1) Define the test scope for the FRS and IWTS; (2) Provide detailed test requirements that can be used to write the specific test procedures; (3) Define data required and measurements to be taken. Where existing methods to obtain these do not exist, enough detail will be provided to define required additional equipment; and (4) Define specific test objectives and acceptance criteria

Iterated unscented Kalman filter for phase unwrapping of interferometric fringes.

Science.gov (United States)

Xie, Xianming

2016-08-22

A fresh phase unwrapping algorithm based on iterated unscented Kalman filter is proposed to estimate unambiguous unwrapped phase of interferometric fringes. This method is the result of combining an iterated unscented Kalman filter with a robust phase gradient estimator based on amended matrix pencil model, and an efficient quality-guided strategy based on heap sort. The iterated unscented Kalman filter that is one of the most robust methods under the Bayesian theorem frame in non-linear signal processing so far, is applied to perform simultaneously noise suppression and phase unwrapping of interferometric fringes for the first time, which can simplify the complexity and the difficulty of pre-filtering procedure followed by phase unwrapping procedure, and even can remove the pre-filtering procedure. The robust phase gradient estimator is used to efficiently and accurately obtain phase gradient information from interferometric fringes, which is needed for the iterated unscented Kalman filtering phase unwrapping model. The efficient quality-guided strategy is able to ensure that the proposed method fast unwraps wrapped pixels along the path from the high-quality area to the low-quality area of wrapped phase images, which can greatly improve the efficiency of phase unwrapping. Results obtained from synthetic data and real data show that the proposed method can obtain better solutions with an acceptable time consumption, with respect to some of the most used algorithms.

Phase formation in Mg-Sn-Si and Mg-Sn-Si-Ca alloys

Energy Technology Data Exchange (ETDEWEB)

Kozlov, A.; Groebner, J. [Institute of Metallurgy, Clausthal University of Technology, Robert-Koch-Str. 42, D-38678 Clausthal-Zellerfeld (Germany); Schmid-Fetzer, R., E-mail: schmid-fetzer@tu-clausthal.de [Institute of Metallurgy, Clausthal University of Technology, Robert-Koch-Str. 42, D-38678 Clausthal-Zellerfeld (Germany)

2011-02-17

Research highlights: > The solidification paths of ternary and quaternary alloys are analyzed in detail, using the tool of thermodynamic calculations. > The precipitation sequence of phases and their amounts compare well with the microstructure of alloys. > The most efficient comparison to the experimental thermal analysis data is done by calculation of the enthalpy variation with temperature. > The viability of a procedure for the selection of multicomponent key samples is demonstrated for the development of the Mg-Ca-Si-Sn phase diagram. - Abstract: Experimental work is done and combined with the Calphad method to generate a consistent thermodynamic description of the Mg-Ca-Si-Sn quaternary system, validated for Mg-rich alloys. The viability of a procedure for the selection of multicomponent key samples is demonstrated for this multicomponent system. Dedicated thermal analysis with DTA/DSC on sealed samples is performed and the microstructure of slowly solidified alloys is analyzed using SEM/EDX. The thermodynamic description and phase diagram of the ternary Mg-Si-Sn system, developed in detail also in this work, deviates significantly from a previous literature proposal. The phase formation in ternary and quaternary alloys is analyzed using the tool of thermodynamic equilibrium and Scheil calculations for the solidification paths and compared with present experimental data. The significant ternary/quaternary solid solubilities of pertinent intermetallic phases are quantitatively introduced in the quaternary Mg-Ca-Si-Sn phase diagram and validated by experimental data.

Clinical outcomes of Laparoscopically Assisted Vaginal Hysterectomy at patients who had previous abdominopelvic surgery

Directory of Open Access Journals (Sweden)

Ali Riza Odabasi

2007-03-01

Full Text Available OBJECTIVE: To determine clinical outcomes of Laparoscopically Assisted Vaginal Hysterectomy (LAVH at patients who had previous abdominopelvic surgery.\tDesign: A clinical observational, prospective, non randomised trial comparing outcomes of 13 patients who had previous abdominopelvic surgery with outcomes of 19 patients who had not surgery.\tSetting: Adnan Menderes University Faculty of Medicine, Department of Obstetrics and Gynecology.\tPatients: Thirty-two subjects [average age 51,1±6,9 (37-66] who had indication of total abdominal hysterectomy and bilateral\tsalpingooferectomy due to benign pathologies.\tInterventions: According to ACOG, LAVH was performed by using the Garry technique at the trocar insertions, the Reich technique\tat the laparoscopic phase and the Heaney technique at the vaginal phase by the same operator. After adhesiolysis and diagnostic procedures, ureters were dissected medially. By coagulating, bilateral round and infundibulopelvic ligaments were cut after the\tmobilisation of bladder. The operation was completed by the same operation team by vaginal approach consequently. At all operations, 80 W unipolar or 150 W bipolar diathermic dissection and 25-35 W unipolar diathermic cutting were performed.\tMain outcome measures: Age, parity, menopausal status, preoperative indications, type of previous abdominopelvic surgey and incision, intraoperative indications, adhesion scores, rate of unintended laparotomy, operative time, uterus weight, loss of blood,\tcomplications, postoperative pain scores and analgesic requirements, time necessary for returning to normal intestinal function, length of hospitalisation and rate of readmission to hospital.\tRESULTS: When compared with the patients who had not previous abdominopelvic surgery, all adhesion scores, uterus weight, operative time and the number of total postoperative complications were found significantly high at patients who had previous\tsurgery. Loss of blood, the rate

PACMan to Help Sort Hubble Proposals

Science.gov (United States)

Kohler, Susanna

2017-04-01

Every year, astronomers submit over a thousand proposals requesting time on the Hubble Space Telescope (HST). Currently, humans must sort through each of these proposals by hand before sending them off for review. Could this burden be shifted to computers?A Problem of VolumeAstronomer Molly Peeples gathered stats on the HST submissions sent in last week for the upcoming HST Cycle 25 (the deadline was Friday night), relative to previous years. This years proposal round broke the record, with over 1200 proposals submitted in total for Cycle 25. [Molly Peeples]Each proposal cycle for HST time attracts on the order of 1100 proposals accounting for far more HST time than is available. The proposals are therefore carefully reviewed by around 150 international members of the astronomy community during a six-month process to select those with the highest scientific merit.Ideally, each proposal will be read by reviewers that have scientific expertise relevant to the proposal topic: if a proposal requests HST time to study star formation, for instance, then the reviewers assigned to it should have research expertise in star formation.How does this matching of proposals to reviewers occur? The current method relies on self-reported categorization of the submitted proposals. This is unreliable, however; proposals are often mis-categorized by submitters due to misunderstanding or ambiguous cases.As a result, the Science Policies Group at the Space Telescope Science Institute (STScI) which oversees the review of HST proposals must go through each of the proposals by hand and re-categorize them. The proposals are then matched to reviewers with self-declared expertise in the same category.With the number of HST proposals on the rise and the expectation that the upcoming James Webb Space Telescope (JWST) will elicit even more proposals for time than Hubble scientists at STScI and NASA are now asking: could the human hours necessary for this task be spared? Could a computer program

Spatial dual-orthogonal (SDO) phase-shifting algorithm by pre-recomposing the interference fringe.

Science.gov (United States)

Wang, Yi; Li, Bingbo; Zhong, Liyun; Tian, Jindong; Lu, Xiaoxu

2017-07-24

In the case that the phase distribution of interferogram is nonuniform and the background/modulation amplitude change rapidly, the current self-calibration algorithms with better performance like principal components analysis (PCA) and advanced iterative algorithm (AIA) cannot work well. In this study, from three or more phase-shifting interferograms with unknown phase-shifts, we propose a spatial dual-orthogonal (SDO) phase-shifting algorithm with high accuracy through using the spatial orthogonal property of interference fringe, in which a new sequence of fringe patterns with uniform phase distribution can be constructed by pre-recomposing original interferograms to determine their corresponding optimum combination coefficients, which are directly related with the phase shifts. Both simulation and experimental results show that using the proposed SDO algorithm, we can achieve accurate phase from the phase-shifting interferograms with nonuniform phase distribution, non-constant background and arbitrary phase shifts. Specially, it is found that the accuracy of phase retrieval with the proposed SDO algorithm is insensitive to the variation of fringe pattern, and this will supply a guarantee for high accuracy phase measurement and application.

Phase-shift interferometry with a digital photocamera

International Nuclear Information System (INIS)

Vannoni, Maurizio; Trivi, Marcelo; Molesini, Giuseppe

2007-01-01

A phase-shift interferometry experiment is proposed, working on a Twyman-Green optical configuration with additional polarization components. A guideline is provided to modern phase-shift interferometry, using concepts and laboratory equipment at the level of undergraduate optics courses

Ensemble of hybrid genetic algorithm for two-dimensional phase unwrapping

Science.gov (United States)

Balakrishnan, D.; Quan, C.; Tay, C. J.

2013-06-01

The phase unwrapping is the final and trickiest step in any phase retrieval technique. Phase unwrapping by artificial intelligence methods (optimization algorithms) such as hybrid genetic algorithm, reverse simulated annealing, particle swarm optimization, minimum cost matching showed better results than conventional phase unwrapping methods. In this paper, Ensemble of hybrid genetic algorithm with parallel populations is proposed to solve the branch-cut phase unwrapping problem. In a single populated hybrid genetic algorithm, the selection, cross-over and mutation operators are applied to obtain new population in every generation. The parameters and choice of operators will affect the performance of the hybrid genetic algorithm. The ensemble of hybrid genetic algorithm will facilitate to have different parameters set and different choice of operators simultaneously. Each population will use different set of parameters and the offspring of each population will compete against the offspring of all other populations, which use different set of parameters. The effectiveness of proposed algorithm is demonstrated by phase unwrapping examples and advantages of the proposed method are discussed.

A modified phase diversity wavefront sensor with a diffraction grating

International Nuclear Information System (INIS)

Luo Qun; Huang Lin-Hai; Gu Nai-Ting; Rao Chang-Hui

2012-01-01

The phase diversity wavefront sensor is one of the tools used to estimate wavefront aberration, and it is often used as a wavefront sensor in adaptive optics systems. However, the performance of the traditional phase diversity wavefront sensor is limited by the accuracy and dynamic ranges of the intensity distribution at the focus and defocus positions of the CCD camera. In this paper, a modified phase diversity wavefront sensor based on a diffraction grating is proposed to improve the ability to measure the wavefront aberration with larger amplitude and higher spatial frequency. The basic principle and the optics construction of the proposed method are also described in detail. The noise propagation property of the proposed method is also analysed by using the numerical simulation method, and comparison between the diffraction grating phase diversity wavefront sensor and the traditional phase diversity wavefront sensor is also made. The simulation results show that the diffraction grating phase diversity wavefront sensor can obviously improve the ability to measure the wavefront aberration, especially the wavefront aberration with larger amplitude and higher spatial frequency

Prediction and synthesis of a family of atomic laminate phases with Kagomé-like and in-plane chemical ordering

Science.gov (United States)

Dahlqvist, Martin; Lu, Jun; Meshkian, Rahele; Tao, Quanzheng; Hultman, Lars; Rosen, Johanna

2017-01-01

The enigma of MAX phases and their hybrids prevails. We probe transition metal (M) alloying in MAX phases for metal size, electronegativity, and electron configuration, and discover ordering in these MAX hybrids, namely, (V2/3Zr1/3)2AlC and (Mo2/3Y1/3)2AlC. Predictive theory and verifying materials synthesis, including a judicious choice of alloying M from groups III to VI and periods 4 and 5, indicate a potentially large family of thermodynamically stable phases, with Kagomé-like and in-plane chemical ordering, and with incorporation of elements previously not known for MAX phases, including the common Y. We propose the structure to be monoclinic C2/c. As an extension of the work, we suggest a matching set of novel MXenes, from selective etching of the A-element. The demonstrated structural design on simultaneous two-dimensional (2D) and 3D atomic levels expands the property tuning potential of functional materials. PMID:28776034

Solid-solid synthesis and structural phase transition process of SmF3

Science.gov (United States)

Yan, Qi-Cao; Guo, Xing-Min

2018-04-01

Mazes of contradictory conclusions have been obtained by previous researches about structural phase transition process of SmF3. In this paper, the single crystals of SmF3 (hexagonal and orthorhombic) were prepared by solid-solid synthesis, which have shown gradual changes in crystal growth modes with the increase temperature and holding time. Furthermore, we propose the phase transition process of in SmF3. Hexagonal symmetry of SmF3 (space group Pnma) was prepared firstly by heating Sm2O3 and NH4HF2 over 40 min at 270 °C. And then orthorhombic symmetry of SmF3 (space group P63mc) was obtained by heating hexagonal symmetry over 10 h at 650 °C. The reaction of SmF3 (hexagonal) = SmF3 (orthorhombic) is extremely sluggish at a low temperature (less than 650 °C), which was seen as a Mixed Grown Region.

Fringe-period selection for a multifrequency fringe-projection phase unwrapping method

International Nuclear Information System (INIS)

Zhang, Chunwei; Zhao, Hong; Jiang, Kejian

2016-01-01

The multi-frequency fringe-projection phase unwrapping method (MFPPUM) is a typical phase unwrapping algorithm for fringe projection profilometry. It has the advantage of being capable of correctly accomplishing phase unwrapping even in the presence of surface discontinuities. If the fringe frequency ratio of the MFPPUM is too large, fringe order error (FOE) may be triggered. FOE will result in phase unwrapping error. It is preferable for the phase unwrapping to be kept correct while the fewest sets of lower frequency fringe patterns are used. To achieve this goal, in this paper a parameter called fringe order inaccuracy (FOI) is defined, dominant factors which may induce FOE are theoretically analyzed, a method to optimally select the fringe periods for the MFPPUM is proposed with the aid of FOI, and experiments are conducted to research the impact of the dominant factors in phase unwrapping and demonstrate the validity of the proposed method. Some novel phenomena are revealed by these experiments. The proposed method helps to optimally select the fringe periods and detect the phase unwrapping error for the MFPPUM. (paper)

DAPs: Deep Action Proposals for Action Understanding

KAUST Repository

Escorcia, Victor

2016-09-17

Object proposals have contributed significantly to recent advances in object understanding in images. Inspired by the success of this approach, we introduce Deep Action Proposals (DAPs), an effective and efficient algorithm for generating temporal action proposals from long videos. We show how to take advantage of the vast capacity of deep learning models and memory cells to retrieve from untrimmed videos temporal segments, which are likely to contain actions. A comprehensive evaluation indicates that our approach outperforms previous work on a large scale action benchmark, runs at 134 FPS making it practical for large-scale scenarios, and exhibits an appealing ability to generalize, i.e. to retrieve good quality temporal proposals of actions unseen in training.

Tunable arbitrary unitary transformer based on multiple sections of multicore fibers with phase control.

Science.gov (United States)

Zhou, Junhe; Wu, Jianjie; Hu, Qinsong

2018-02-05

In this paper, we propose a novel tunable unitary transformer, which can achieve arbitrary discrete unitary transforms. The unitary transformer is composed of multiple sections of multi-core fibers with closely aligned coupled cores. Phase shifters are inserted before and after the sections to control the phases of the waves in the cores. A simple algorithm is proposed to find the optimal phase setup for the phase shifters to realize the desired unitary transforms. The proposed device is fiber based and is particularly suitable for the mode division multiplexing systems. A tunable mode MUX/DEMUX for a three-mode fiber is designed based on the proposed structure.

Walking pattern classification and walking distance estimation algorithms using gait phase information.

Science.gov (United States)

Wang, Jeen-Shing; Lin, Che-Wei; Yang, Ya-Ting C; Ho, Yu-Jen

2012-10-01

This paper presents a walking pattern classification and a walking distance estimation algorithm using gait phase information. A gait phase information retrieval algorithm was developed to analyze the duration of the phases in a gait cycle (i.e., stance, push-off, swing, and heel-strike phases). Based on the gait phase information, a decision tree based on the relations between gait phases was constructed for classifying three different walking patterns (level walking, walking upstairs, and walking downstairs). Gait phase information was also used for developing a walking distance estimation algorithm. The walking distance estimation algorithm consists of the processes of step count and step length estimation. The proposed walking pattern classification and walking distance estimation algorithm have been validated by a series of experiments. The accuracy of the proposed walking pattern classification was 98.87%, 95.45%, and 95.00% for level walking, walking upstairs, and walking downstairs, respectively. The accuracy of the proposed walking distance estimation algorithm was 96.42% over a walking distance.

Time Series Decomposition into Oscillation Components and Phase Estimation.

Science.gov (United States)

Matsuda, Takeru; Komaki, Fumiyasu

2017-02-01

Many time series are naturally considered as a superposition of several oscillation components. For example, electroencephalogram (EEG) time series include oscillation components such as alpha, beta, and gamma. We propose a method for decomposing time series into such oscillation components using state-space models. Based on the concept of random frequency modulation, gaussian linear state-space models for oscillation components are developed. In this model, the frequency of an oscillator fluctuates by noise. Time series decomposition is accomplished by this model like the Bayesian seasonal adjustment method. Since the model parameters are estimated from data by the empirical Bayes' method, the amplitudes and the frequencies of oscillation components are determined in a data-driven manner. Also, the appropriate number of oscillation components is determined with the Akaike information criterion (AIC). In this way, the proposed method provides a natural decomposition of the given time series into oscillation components. In neuroscience, the phase of neural time series plays an important role in neural information processing. The proposed method can be used to estimate the phase of each oscillation component and has several advantages over a conventional method based on the Hilbert transform. Thus, the proposed method enables an investigation of the phase dynamics of time series. Numerical results show that the proposed method succeeds in extracting intermittent oscillations like ripples and detecting the phase reset phenomena. We apply the proposed method to real data from various fields such as astronomy, ecology, tidology, and neuroscience.

Phase object retrieval through scattering medium

Science.gov (United States)

Zhao, Ming; Zhao, Meijing; Wu, Houde; Xu, Wenhai

2018-05-01

Optical imaging through a scattering medium has been an interesting and important research topic, especially in the field of biomedical imaging. However, it is still a challenging task due to strong scattering. This paper proposes to recover the phase object behind the scattering medium from one single-shot speckle intensity image using calibrated transmission matrices (TMs). We construct the forward model as a non-linear mapping, since the intensity image loses the phase information, and then a generalized phase retrieval algorithm is employed to recover the hidden object. Moreover, we show that a phase object can be reconstructed with a small portion of the speckle image captured by the camera. The simulation is performed to demonstrate our scheme and test its performance. Finally, a real experiment is set up, we measure the TMs from the scattering medium, and then use it to reconstruct the hidden object. We show that a phase object of size 32 × 32 is retrieved from 150 × 150 speckle grains, which is only 1/50 of the speckles area. We believe our proposed method can benefit the community of imaging through the scattering medium.

Robust information encryption diffractive-imaging-based scheme with special phase retrieval algorithm for a customized data container

Science.gov (United States)

Qin, Yi; Wang, Zhipeng; Wang, Hongjuan; Gong, Qiong; Zhou, Nanrun

2018-06-01

The diffractive-imaging-based encryption (DIBE) scheme has aroused wide interesting due to its compact architecture and low requirement of conditions. Nevertheless, the primary information can hardly be recovered exactly in the real applications when considering the speckle noise and potential occlusion imposed on the ciphertext. To deal with this issue, the customized data container (CDC) into DIBE is introduced and a new phase retrieval algorithm (PRA) for plaintext retrieval is proposed. The PRA, designed according to the peculiarity of the CDC, combines two key techniques from previous approaches, i.e., input-support-constraint and median-filtering. The proposed scheme can guarantee totally the reconstruction of the primary information despite heavy noise or occlusion and its effectiveness and feasibility have been demonstrated with simulation results.

Phase-covariant quantum cloning of qudits

International Nuclear Information System (INIS)

Fan Heng; Imai, Hiroshi; Matsumoto, Keiji; Wang, Xiang-Bin

2003-01-01

We study the phase-covariant quantum cloning machine for qudits, i.e., the input states in a d-level quantum system have complex coefficients with arbitrary phase but constant module. A cloning unitary transformation is proposed. After optimizing the fidelity between input state and single qudit reduced density operator of output state, we obtain the optimal fidelity for 1 to 2 phase-covariant quantum cloning of qudits and the corresponding cloning transformation

Physical Improvements in Exciter/Igniter Units, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The proposed Phase 2 project consists of the physical integration of our Phase 1 small, compact exciter with a "flight like" igniter or spark plug capable of...

Self-Healing Inflatable Extraterrestrial Shield (SHIELD), Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The team of Astro Terra Corp, Virginia Commonwealth University (VCU), and Virginia Tech (VT) propose the development of a composite polymer over Phase-I and Phase-II...

Self-Calibrating Vector Helium Magnetometer (SVHM), Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This Phase I SBIR proposal describes proposed development of a conceptual design for a Self-Calibrating Vector Helium Magnetometer (SVHM) for design and fabrication...

On new proposal for holographic BCFT

Energy Technology Data Exchange (ETDEWEB)

Chu, Chong-Sun; Miao, Rong-Xin [Department of Physics, National Tsing-Hua University,Hsinchu 30013, Taiwan (China); Physics Division, National Center for Theoretical Sciences,National Tsing-Hua University, Hsinchu 30013, Taiwan (China); Guo, Wu-Zhong [Physics Division, National Center for Theoretical Sciences,National Tsing-Hua University, Hsinchu 30013, Taiwan (China)

2017-04-14

This paper is an extended version of our short letter on a new proposal for holographic boundary conformal field, i.e., BCFT. By using the Penrose-Brown-Henneaux (PBH) transformation, we successfully obtain the expected boundary Weyl anomaly. The obtained boundary central charges satisfy naturally a c-like theorem holographically. We then develop an approach of holographic renormalization for BCFT, and reproduce the correct boundary Weyl anomaly. This provides a non-trivial check of our proposal. We also investigate the holographic entanglement entropy of BCFT and find that our proposal gives the expected orthogonal condition that the minimal surface must be normal to the spacetime boundaries if they intersect. This is another support for our proposal. We also find that the entanglement entropy depends on the boundary conditions of BCFT and the distance to the boundary; and that the entanglement wedge behaves a phase transition, which is important for the self-consistency of AdS/BCFT. Finally, we show that the proposal of https://arxiv.org/abs/1105.5165 is too restrictive that it always make vanishing some of the boundary central charges.

Design of clinical trials Phase I and II with radiopharmaceuticals

International Nuclear Information System (INIS)

Giannone, C.A.; Soroa, V.E.

2015-01-01

We presented some usual designs for clinical studies in Phase I and Phase II. For Phase I we considered the 3 + 3 Classic design, designs with accelerated titration and those with dose escalation schemes with overdose control (EWOC). For Phase II designs with efficacy outcomes are presented. The design proposed by Fleming is discussed as well as those with inclusion of patients in two stages: Gehan’s design and the Optimal two–stage Simon’s design. We also discussed the design of combined endpoints of efficacy and safety of Bryant and Day with an application example of therapeutically Lu-177. Finally some proposals for phase II trials with control group are considered. (authors) [es

The Uhlenbeck-Ford model: Exact virial coefficients and application as a reference system in fluid-phase free-energy calculations

Science.gov (United States)

Paula Leite, Rodolfo; Freitas, Rodrigo; Azevedo, Rodolfo; de Koning, Maurice

2016-11-01

The Uhlenbeck-Ford (UF) model was originally proposed for the theoretical study of imperfect gases, given that all its virial coefficients can be evaluated exactly, in principle. Here, in addition to computing the previously unknown coefficients B11 through B13, we assess its applicability as a reference system in fluid-phase free-energy calculations using molecular simulation techniques. Our results demonstrate that, although the UF model itself is too soft, appropriately scaled Uhlenbeck-Ford (sUF) models provide robust reference systems that allow accurate fluid-phase free-energy calculations without the need for an intermediate reference model. Indeed, in addition to the accuracy with which their free energies are known and their convenient scaling properties, the fluid is the only thermodynamically stable phase for a wide range of sUF models. This set of favorable properties may potentially put the sUF fluid-phase reference systems on par with the standard role that harmonic and Einstein solids play as reference systems for solid-phase free-energy calculations.

PHASE BEHAVIOR OF LIGHT GASES IN HYDROCARBON AND AQUEOUS SOLVENTS

Energy Technology Data Exchange (ETDEWEB)

KHALED A.M. GASEM; ROBERT L. ROBINSON, JR.

1998-08-31

Under previous support from the Department of Energy, an experimental facility has been established and operated to measure valuable vapor-liquid equilibrium data for systems of interest in the production and processing of coal fluids. To facilitate the development and testing of models for prediction of the phase behavior for such systems, we have acquired substantial amounts of data on the equilibrium phase compositions for binary mixtures of heavy hydrocarbon solvents with a variety of supercritical solutes, including hydrogen, methane, ethane, carbon monoxide, and carbon dioxide. The present project focuses on measuring the phase behavior of light gases and water in Fischer-Tropsch (F-T) type solvents at conditions encountered in indirect liquefaction processes and evaluating and developing theoretically-based correlating frameworks to predict the phase behavior of such systems. Specific goals of the proposed work include (a) developing a state-of-the-art experimental facility to permit highly accurate measurements of equilibrium phase compositions (solubilities) of challenging F-T systems, (b) measuring these properties for systematically-selected binary, ternary and molten F-T wax mixtures to provide critically needed input data for correlation development, (c) developing and testing models suitable for describing the phase behavior of such mixtures, and (d) presenting the modeling results in generalized, practical formats suitable for use in process engineering calculations. During the present period, the Park-Gasem-Robinson (PGR) equation of state (EOS) has been modified to improve its volumetric and equilibrium predictions. Specifically, the attractive term of the PGR equation was modified to enhance the flexibility of the model, and a new expression was developed for the temperature dependence of the attractive term in this segment-segment interaction model. The predictive capability of the modified PGR EOS for vapor pressure, and saturated liquid and

Development of New Correlation and Assessment of Correlations for Two-Phase Pressure Drop in Rectangular Microchannels

International Nuclear Information System (INIS)

Choi, Chi Woong; Yu, Dong In; Kim, Moo Hwan

2010-01-01

There are two kinds of models in two-phase pressured drop; homogeneous flow model and separated flow model. Many previous researchers have developed correlations for two-phase pressure drop in a microchannel. Most correlations were modified Lockhart and Martinelli's correlation, which was based on the separated flow model. In this study, experiments for adiabatic liquid water and nitrogen gas flow in rectangular microchannels were conducted to investigate two-phase pressure drop in the rectangular microchannels. Two-phase frictional pressure drop in the rectangular microchannels is highly related with flow regime. Homogeneous model with six two-phase viscosity models: Owen(21)'s, MacAdams(22)'s, Cicchitti et al.(23)'s, Dukler et al.(24)'s, Beattie and Whalley(25)'s, Lin et al.(26)'s models and six separated flow models: Lockhart and Martinelli(27)'s, Chisholm(31)'s, Zhang et al.(15)'s, Lee and Lee(5)'s, Moriyama and Inue(4)'s, Qu and Mudawar(8)'s models were assessed with our experimental data. The best two-phase viscosity model is Beattie and Whalley's model. The best separated flow model is Qu and Mudawar's correlation. Flow regime dependency in both homogeneous and separated flow models was observed. Therefore, new flow pattern based correlations for both homogeneous and separated flow models were individually proposed

Movements Indicate Threat Response Phases in Children at Risk for Anxiety.

Science.gov (United States)

McGinnis, Ellen W; McGinnis, Ryan S; Muzik, Maria; Hruschak, Jessica; Lopez-Duran, Nestor L; Perkins, Noel C; Fitzgerald, Kate; Rosenblum, Katherine L

2017-09-01

Temporal phases of threat response, including potential threat (anxiety), acute threat (startle, fear), and post-threat response modulation, have been identified as the underlying markers of anxiety disorders. Objective measures of response during these phases may help identify children at risk for anxiety; however, the complexity of current assessment techniques prevent their adoption in many research and clinical contexts. We propose an alternative technology, an inertial measurement unit (IMU), that enables noninvasive measurement of the movements associated with threat response, and test its ability to detect threat response phases in young children at a heightened risk for developing anxiety. We quantified the motion of 18 children (3-7 years old) during an anxiety-/fear-provoking behavioral task using an IMU. Specifically, measurements from a single IMU secured to the child's waist were used to extract root-mean-square acceleration and angular velocity in the horizontal and vertical directions, and tilt and yaw range of motion during each threat response phase. IMU measurements detected expected differences in child motion by threat phase. Additionally, potential threat motion was positively correlated to familial anxiety risk, startle range of motion was positively correlated with child internalizing symptoms, and response modulation motion was negatively correlated to familial anxiety risk. Results suggest differential theory-driven threat response phases and support previous literature connecting maternal child risk to anxiety with behavioral measures using more feasible objective methods. This is the first study demonstrating the utility of an IMU for characterizing the motion of young children to mark the phases of threat response modulation. The technique provides a novel and objective measure of threat response for mental health researchers.

Phase Noise Compensation for OFDM Systems

Science.gov (United States)

Leshem, Amir; Yemini, Michal

2017-11-01

We describe a low complexity method for time domain compensation of phase noise in OFDM systems. We extend existing methods in several respects. First we suggest using the Karhunen-Lo\\'{e}ve representation of the phase noise process to estimate the phase noise. We then derive an improved datadirected choice of basis elements for LS phase noise estimation and present its total least square counterpart problem. The proposed method helps overcome one of the major weaknesses of OFDM systems. We also generalize the time domain phase noise compensation to the multiuser MIMO context. Finally we present simulation results using both simulated and measured phased noise. We quantify the tracking performance in the presence of residual carrier offset.

Proposal for Construction/Demonstration/Implementation of A Material Handling System

International Nuclear Information System (INIS)

Jim Jnatt

2001-01-01

Vortec Corporation, the United States Enrichment Corporation (USEC) and DOE/Paducah propose to complete the technology demonstration and the implementation of the Material Handling System developed under Contract Number DE-AC21-92MC29120. The demonstration testing and operational implementation will be done at the Paducah Gaseous Diffusion Plant. The scope of work, schedule and cost for the activities are included in this proposal. A description of the facility to be constructed and tested is provided in Exhibit 1, attached. The USEC proposal for implementation at Paducah is presented in Exhibit 2, and the commitment letters from the site are included in Exhibit 3. Under our agreements with USEC, Bechtel Jacobs Corporation and DOE/Paducah, Vortec will be responsible for the construction of the demonstration facility as documented in the engineering design package submitted under Phase 4 of this contract on August 9, 2001. USEC will have responsibility for the demonstration testing and commercial implementation of the plant. The demonstration testing and initial commercial implementation of the technology will be achieved by means of a USEC work authorization task with the Bechtel Jacobs Corporation. The initial processing activities will include the processing of approximately 4,250 drums of LLW. Subsequent processing of LLW and TSCA/LLW will be done under a separate contract or work authorization task. To meet the schedule for commercial implementation, it is important that the execution of the Phase 4 project option for construction of the demonstration system be executed as soon as possible. The schedule we have presented herein assumes initiation of the construction phase by the end of September 2001. Vortec proposes to complete construction of the demonstration test system for an estimated cost of $3,254,422. This price is based on the design submitted to DOE/NETL under the Phase 4 engineering design deliverable (9 august 2001). The cost is subject to the

A proposed HTTP service based IDS

Directory of Open Access Journals (Sweden)

Mohamed M. Abd-Eldayem

2014-03-01

Full Text Available The tremendous growth of the web-based applications has increased information security vulnerabilities over the Internet. Security administrators use Intrusion-Detection System (IDS to monitor network traffic and host activities to detect attacks against hosts and network resources. In this paper IDS based on Naïve Bayes classifier is analyzed. The main objective is to enhance IDS performance through preparing the training data set allowing to detect malicious connections that exploit the http service. Results of application are demonstrated and discussed. In the training phase of the proposed IDS, at first a feature selection technique based on Naïve Bayes classifier is used, this technique identifies the most important HTTP traffic features that can be used to detect HTTP attacks. In the testing and running phases proposed IDS classifies the network traffic based on the requested service, then based on the selected features Naïve Bayes classifier is used to analyze the HTTP service based traffic and identifies the HTTP normal connections and attacks. The performance of the IDS is measured through experiments using NSL-KDD data set. The results show that the detection rate of the IDS is about 99%, the false-positive rate is about 1%, and the false-negative rate is about 0.25%; therefore, proposed IDS holds the highest detection rate and the lowest false alarm compared with other leading IDS. In addition, the proposed IDS based on Naïve Bayes is used to classify network connections as a normal or attack. And it holds a high detection rate and a low false alarm.

Fischer Indole Synthesis in the Gas Phase, the Solution Phase, and at the Electrospray Droplet Interface.

Science.gov (United States)

Bain, Ryan M; Ayrton, Stephen T; Cooks, R Graham

2017-07-01

Previous reports have shown that reactions occurring in the microdroplets formed during electrospray ionization can, under the right conditions, exhibit significantly greater rates than the corresponding bulk solution-phase reactions. The observed acceleration under electrospray ionization could result from a solution-phase, a gas-phase, or an interfacial reaction. This study shows that a gas-phase ion/molecule (or ion/ion) reaction is not responsible for the observed rate enhancement in the particular case of the Fischer indole synthesis. The results show that the accelerated reaction proceeds in the microdroplets, and evidence is provided that an interfacial process is involved. Graphical Abstract GRAPHICAL ABSTRACT TEXT HERE] -->.

Phase diagram of the Ge-rich of the Ba–Ge system and characterisation of single-phase BaGe4

International Nuclear Information System (INIS)

Prokofieva, Violetta K.; Pavlova, Lydia M.

2014-01-01

Highlights: • The Ba-Ge phase diagram for the range 50–100 at.% Ge was constructed. • Single-phase BaGe 4 grown by the Czochralski method was characterised. • A phenomenological model for a liquid-liquid phase transition is proposed. - Abstract: The Ba–Ge binary system has been investigated by several authors, but some uncertainties remain regarding phases with Ba/Ge ⩽ 2. The goal of this work was to resolve the uncertainty about the current phase diagram of Ba–Ge by performing DTA, X-ray powder diffraction, metallographic and chemical analyses, and measurements of the electrical conductivity and viscosity. The experimental Ba–Ge phase diagram over the composition range of 50–100 at.% Ge was constructed from the cooling curves and single-phase BaGe 4 grown by the Czochralski crystal pulling method was characterised. Semiconducting BaGe 4 crystallised peritectically from the liquid phase near the eutectic. In the liquid state, the caloric effects were observed in the DTA curves at 1050 °C where there are no definite phase lines in the Ba–Ge phase diagram. These effects are confirmed by significant changes in the viscosity and electrical conductivity of a Ba–Ge alloy with eutectic composition at this temperature. A phenomenological model based on two different approaches, a phase approach and a chemical approach, is proposed to explain the isothermal liquid–liquid phase transition observed in the Ba–Ge system from the Ge side. Our results suggest that this transition is due to the peritectic reactions in the liquid phase. This reversible phase transition results in the formation of precursors of various metastable clathrate phases and is associated with sudden changes in the structure of Ba–Ge liquid alloys. Characteristics of both first- and second-order phase transitions are observed. Charge transfer appears to play an important role in this transition

Diagrammatic methods in phase-space regularization

International Nuclear Information System (INIS)

Bern, Z.; Halpern, M.B.; California Univ., Berkeley

1987-11-01

Using the scalar prototype and gauge theory as the simplest possible examples, diagrammatic methods are developed for the recently proposed phase-space form of continuum regularization. A number of one-loop and all-order applications are given, including general diagrammatic discussions of the nogrowth theorem and the uniqueness of the phase-space stochastic calculus. The approach also generates an alternate derivation of the equivalence of the large-β phase-space regularization to the more conventional coordinate-space regularization. (orig.)

Security enhancement of double random phase encoding using rear-mounted phase masking

Science.gov (United States)

Chen, Junxin; Zhang, Yu; Li, Jinchang; Zhang, Li-bo

2018-02-01

In this paper, a security enhancement for double random phase encoding (DRPE) by introducing a rear-mounted phase masking procedure is presented. Based on exhaustively studying the cryptanalysis achievements of DRPE and its variants, invalidation of the second lens, which plays a critical role in cryptanalyzing processes, is concluded. The improved system can exploit the security potential of the second lens and consequently strengthen the security of DRPE. Experimental results and security analyses are presented in detail to demonstrate the security potential of the proposed cryptosystem.

Dark-field electron holography for the measurement of geometric phase

International Nuclear Information System (INIS)

Hytch, M.J.; Houdellier, F.; Huee, F.; Snoeck, E.

2011-01-01

The genesis, theoretical basis and practical application of the new electron holographic dark-field technique for mapping strain in nanostructures are presented. The development places geometric phase within a unified theoretical framework for phase measurements by electron holography. The total phase of the transmitted and diffracted beams is described as a sum of four contributions: crystalline, electrostatic, magnetic and geometric. Each contribution is outlined briefly and leads to the proposal to measure geometric phase by dark-field electron holography (DFEH). The experimental conditions, phase reconstruction and analysis are detailed for off-axis electron holography using examples from the field of semiconductors. A method for correcting for thickness variations will be proposed and demonstrated using the phase from the corresponding bright-field electron hologram. -- Highlights: → Unified description of phase measurements in electron holography. → Detailed description of dark-field electron holography for geometric phase measurements. → Correction procedure for systematic errors due to thickness variations.

Previous radiotherapy and the clinical activity and toxicity of pembrolizumab in the treatment of non-small-cell lung cancer: a secondary analysis of the KEYNOTE-001 phase 1 trial.

Science.gov (United States)

Shaverdian, Narek; Lisberg, Aaron E; Bornazyan, Krikor; Veruttipong, Darlene; Goldman, Jonathan W; Formenti, Silvia C; Garon, Edward B; Lee, Percy

2017-07-01

Preclinical studies have found radiotherapy enhances antitumour immune responses. We aimed to assess disease control and pulmonary toxicity in patients who previously received radiotherapy for non-small-cell lung cancer (NSCLC) before receiving pembrolizumab. We assessed patients with advanced NSCLC treated on the phase 1 KEYNOTE-001 trial at a single institution (University of California, Los Angeles, CA, USA). Patients were aged 18 years or older, had an Eastern Cooperative Oncology Group performance status of 1 or less, had adequate organ function, and no history of pneumonitis. Patients received pembrolizumab at a dose of either 2 mg/kg of bodyweight or 10 mg/kg every 3 weeks, or 10 mg/kg every 2 weeks, until disease progression, unacceptable toxicity, or other protocol-defined reasons for discontinuation. Disease response and pulmonary toxicity were prospectively assessed by Immune-related Response Criteria and Common Terminology Criteria for Adverse Events version 4.0. The primary objective of the KEYNOTE-001 trial was to assess the safety, side-effect profile, and antitumour activity of pembrolizumab. For our secondary analysis, patients were divided into subgroups to compare patients who previously received radiotherapy with patients who had not. Our primary objective was to determine whether previous radiotherapy affected progression-free survival, overall survival, and pulmonary toxicity in the intention-to-treat population. The KEYNOTE-001 trial was registered with ClinicalTrials.gov, number NCT01295827. Between May 22, 2012, and July 11, 2014, 98 patients were enrolled and received their first cycle of pembrolizumab. One patient was lost to follow-up. 42 (43%) of 97 patients had previously received any radiotherapy for the treatment of NSCLC before the first cycle of pembrolizumab. 38 (39%) of 97 patients received extracranial radiotherapy and 24 (25%) of 97 patients received thoracic radiotherapy. Median follow-up for surviving patients was 32·5

Amended proposal for R ampersand D on a cluster klystron

International Nuclear Information System (INIS)

Fernow, R.C.; Fischer, J.; Gallardo, J.C.; Kirk, H.G.; Ko, S.K.; Palmer, R.B.; Ulc, S.; Wang, H.

1993-01-01

This Proposal is an updated version of FWP submitted in March 1992. Significant work has been done since the original proposal, and much of this is reported on in this update. In addition there have been several changes made, some in response to suggestions made by the three reviews sent to us in December, 1992. The new information and changes include: Technical information on the proposed design of the magnetron gun, the magnet, acceleration gap, and electrical system (including a comment on efficiency loss due to high-voltage leakage current). Modification of the phase I and II tests to allow operation of the gun and klystron off the axis of the magnet, thus simulating the magnet situation when multiple beams are used. Modification of phases III and IV to test a cluster of three beams: first a three beam gun, and then three beams with a klystron on one of them. We have added a phase V which would be the testing of a full three-beam demonstration klystron. The mod-anode pulser would now be located on the high voltage deck instead of externally. Power for the pulser and other high voltage components would now be provided by an isolation transformer instead of from a lead battery. We believe these changes have improved the proposed program and thank the reviewers for their constructive suggestions. The design is still evolving. Relatively little work has been done on the detailed klystron design, and none on the beam dump

Yakima Basin Fish Passage Project, Phase 2

International Nuclear Information System (INIS)

1991-08-01

Implementation of the Yakima Basin Fish Passage Project -- Phase 2 would significantly improve the production of anadromous fish in the Yakima River system. The project would provide offsite mitigation and help to compensate for lower Columbia River hydroelectric fishery losses. The Phase 2 screens would allow greater numbers of juvenile anadromous fish to survive. As a consequence, there would be higher returns of adult salmon and steelhead to the Yakima River. The proposed action would play an integral part in the overall Yakima River anadromous fish enhancement program (fish passage improvement, habitat enhancement, hatchery production increases, and harvest management). These would be environmental benefits associated with implementation of the Fish Passage and Protective Facilities Phase 2 Project. Based on the evaluation presented in this assessment, there would be no significant adverse environmental impacts if the proposed action was carried forward. No significant adverse environmental effects have been identified from construction and operation of the Yakima Phase 2 fish passage project. Proper design and implementation of the project will ensure no adverse effects will occur. Based on the information in this environmental analysis, BPA's and Reclamation's proposal to construct these facilities does not constitute a major Federal action that could significantly affect the quality of the human environment. 8 refs., 4 figs., 6 tabs

Subthreshold electrical transport in amorphous phase-change materials

International Nuclear Information System (INIS)

Gallo, Manuel Le; Kaes, Matthias; Sebastian, Abu; Krebs, Daniel

2015-01-01

Chalcogenide-based phase-change materials play a prominent role in information technology. In spite of decades of research, the details of electrical transport in these materials are still debated. In this article, we present a unified model based on multiple-trapping transport together with 3D Poole–Frenkel emission from a two-center Coulomb potential. With this model, we are able to explain electrical transport both in as-deposited phase-change material thin films, similar to experimental conditions in early work dating back to the 1970s, and in melt-quenched phase-change materials in nanometer-scale phase-change memory devices typically used in recent studies. Experimental measurements on two widely different device platforms show remarkable agreement with the proposed mechanism over a wide range of temperatures and electric fields. In addition, the proposed model is able to seamlessly capture the temporal evolution of the transport properties of the melt-quenched phase upon structural relaxation. (paper)

Previous experience in manned space flight: A survey of human factors lessons learned

Science.gov (United States)

Chandlee, George O.; Woolford, Barbara

1993-01-01

Previous experience in manned space flight programs can be used to compile a data base of human factors lessons learned for the purpose of developing aids in the future design of inhabited spacecraft. The objectives are to gather information available from relevant sources, to develop a taxonomy of human factors data, and to produce a data base that can be used in the future for those people involved in the design of manned spacecraft operations. A study is currently underway at the Johnson Space Center with the objective of compiling, classifying, and summarizing relevant human factors data bearing on the lessons learned from previous manned space flights. The research reported defines sources of data, methods for collection, and proposes a classification for human factors data that may be a model for other human factors disciplines.

Role of Reversible Phase Transformation for Strong Piezoelectric Performance at the Morphotropic Phase Boundary

Science.gov (United States)

Liu, Hui; Chen, Jun; Huang, Houbing; Fan, Longlong; Ren, Yang; Pan, Zhao; Deng, Jinxia; Chen, Long-Qing; Xing, Xianran

2018-01-01

A functional material with coexisting energetically equivalent phases often exhibits extraordinary properties such as piezoelectricity, ferromagnetism, and ferroelasticity, which is simultaneously accompanied by field-driven reversible phase transformation. The study on the interplay between such phase transformation and the performance is of great importance. Here, we have experimentally revealed the important role of field-driven reversible phase transformation in achieving enhanced electromechanical properties using in situ high-energy synchrotron x-ray diffraction combined with 2D geometry scattering technology, which can establish a comprehensive picture of piezoelectric-related microstructural evolution. High-throughput experiments on various Pb /Bi -based perovskite piezoelectric systems suggest that reversible phase transformation can be triggered by an electric field at the morphotropic phase boundary and the piezoelectric performance is highly related to the tendency of electric-field-driven phase transformation. A strong tendency of phase transformation driven by an electric field generates peak piezoelectric response. Further, phase-field modeling reveals that the polarization alignment and the piezoelectric response can be much enhanced by the electric-field-driven phase transformation. The proposed mechanism will be helpful to design and optimize the new piezoelectrics, ferromagnetics, or other related functional materials.

Analysis of expansion phase experiments with improved approximation schemes

International Nuclear Information System (INIS)

Foit, J.J.

1987-05-01

A steady-state flow of a single-phase and incompressible fluid across a singularity is studied. Based on these theoretical considerations new approximation methods for the pressure gradient term in the SIMMER-II momentum equations are proposed which give a satisfactory pressure change in flows across singularities. The expansion phase experiments with a dipplate performed by SRI-International are evaluated to examine the quality of the proposed approximation schemes. (orig.) [de

Phase unwrapping algorithm based on multi-frequency fringe projection and fringe background for fringe projection profilometry

International Nuclear Information System (INIS)

Zhang, Chunwei; Zhao, Hong; Gu, Feifei; Ma, Yueyang

2015-01-01

A phase unwrapping algorithm specially designed for the phase-shifting fringe projection profilometry (FPP) is proposed. It combines a revised dual-frequency fringe projectionalgorithm and a proposed fringe background based quality guided phase unwrapping algorithm (FB-QGPUA). Phase demodulated from the high-frequency fringe patterns is partially unwrapped by that demodulated from the low-frequency ones. Then FB-QGPUA is adopted to further unwrap the partially unwrapped phase. Influences of the phase error on the measurement are researched. Strategy to select the fringe pitch is given. Experiments demonstrate that the proposed method is very robust and efficient. (paper)

Phase-only stereoscopic hologram calculation based on Gerchberg–Saxton iterative algorithm

International Nuclear Information System (INIS)

Xia Xinyi; Xia Jun

2016-01-01

A phase-only computer-generated holography (CGH) calculation method for stereoscopic holography is proposed in this paper. The two-dimensional (2D) perspective projection views of the three-dimensional (3D) object are generated by the computer graphics rendering techniques. Based on these views, a phase-only hologram is calculated by using the Gerchberg–Saxton (GS) iterative algorithm. Comparing with the non-iterative algorithm in the conventional stereoscopic holography, the proposed method improves the holographic image quality, especially for the phase-only hologram encoded from the complex distribution. Both simulation and optical experiment results demonstrate that our proposed method can give higher quality reconstruction comparing with the traditional method. (special topic)

Sensor-Based Auto-Focusing System Using Multi-Scale Feature Extraction and Phase Correlation Matching

Directory of Open Access Journals (Sweden)

Jinbeum Jang

2015-03-01

Full Text Available This paper presents a novel auto-focusing system based on a CMOS sensor containing pixels with different phases. Robust extraction of features in a severely defocused image is the fundamental problem of a phase-difference auto-focusing system. In order to solve this problem, a multi-resolution feature extraction algorithm is proposed. Given the extracted features, the proposed auto-focusing system can provide the ideal focusing position using phase correlation matching. The proposed auto-focusing (AF algorithm consists of four steps: (i acquisition of left and right images using AF points in the region-of-interest; (ii feature extraction in the left image under low illumination and out-of-focus blur; (iii the generation of two feature images using the phase difference between the left and right images; and (iv estimation of the phase shifting vector using phase correlation matching. Since the proposed system accurately estimates the phase difference in the out-of-focus blurred image under low illumination, it can provide faster, more robust auto focusing than existing systems.

A Three-Phase Multiobjective Mechanism for Selecting Retail Stores to Close

Directory of Open Access Journals (Sweden)

Rong-Chang Chen

2016-01-01

Full Text Available To operate a successful and growing business, a retail store manager has to make tough decisions about selectively closing underperforming stores. In this paper, we propose using a three-phase multiobjective mechanism to help retail industry practitioners determine which stores to close. In the first phase, a geographic information system (GIS and k-means clustering algorithm are used to divide all the stores into clusters. In the second phase, stores can be strategically selected according to the requirements of the company and the attributes of the stores. In the third phase, a neighborhood-based multiobjective genetic algorithm (NBMOGA is utilized to determine which stores to close. To examine the effectiveness of the proposed three-phase mechanism, a variety of experiments are performed, based partly on a real dataset from a stock-list company in Taiwan. Results from the experiments show that the proposed three-phase mechanism can help efficiently decide which store locations to close. In addition, the neighborhood radius has a considerable influence on the results.

Phase development and kinetics of high temperature Bi-2223 phase

International Nuclear Information System (INIS)

Yavuz, M.; Maeda, H.; Hua, K.L.; Shi, X.D.

1998-01-01

The two-dimensional nucleation (random)-growth mechanism were observed as a support for the related previous works, which is attributable to the growth of the Bi-2223 grain in the a-b plane direction of the Bi-2212 matrix is being much faster than in the c-direction, or that the early-formed plate-like 2212 phase confines the 2223 product. At the beginning of the reaction, the additional phases are partially melted. Because of the structure, composition and thermal fluctuation, the 2223 nucleates and grows in the phase boundary between the liquid phase and Bi-2212. It was shown here that the nucleation and the growth rate were relatively fast between 0 and 36 h. At the final stage, between 36 and 60 h, because of the impingement of the growth fronts of different nuclei, the high formation rate of 2223 is suppressed. The major reactant 2212 remains as a solid and its plate-like configuration determines the two dimensional nature of the reaction. The amount of liquid forms during reaction is small. (orig.)

Laparoscopy After Previous Laparotomy

Directory of Open Access Journals (Sweden)

Zulfo Godinjak

2006-11-01

Full Text Available Following the abdominal surgery, extensive adhesions often occur and they can cause difficulties during laparoscopic operations. However, previous laparotomy is not considered to be a contraindication for laparoscopy. The aim of this study is to present that an insertion of Veres needle in the region of umbilicus is a safe method for creating a pneumoperitoneum for laparoscopic operations after previous laparotomy. In the last three years, we have performed 144 laparoscopic operations in patients that previously underwent one or two laparotomies. Pathology of digestive system, genital organs, Cesarean Section or abdominal war injuries were the most common causes of previouslaparotomy. During those operations or during entering into abdominal cavity we have not experienced any complications, while in 7 patients we performed conversion to laparotomy following the diagnostic laparoscopy. In all patients an insertion of Veres needle and trocar insertion in the umbilical region was performed, namely a technique of closed laparoscopy. Not even in one patient adhesions in the region of umbilicus were found, and no abdominal organs were injured.

Multiple topological phases in phononic crystals

KAUST Repository

Chen, Zeguo; Wu, Ying

2017-01-01

We report a new topological phononic crystal in a ring-waveguide acoustic system. In the previous reports on topological phononic crystals, there are two types of topological phases: quantum Hall phase and quantum spin Hall phase. A key point in achieving quantum Hall insulator is to break the time-reversal (TR) symmetry, and for quantum spin Hall insulator, the construction of pseudo-spin is necessary. We build such pseudo-spin states under particular crystalline symmetry (C-6v) and then break the degeneracy of the pseudo-spin states by introducing airflow to the ring. We study the topology evolution by changing both the geometric parameters of the unit cell and the strength of the applied airflow. We find that the system exhibits three phases: quantum spin Hall phase, conventional insulator phase and a new quantum anomalous Hall phase.

Multiple topological phases in phononic crystals

KAUST Repository

Chen, Zeguo

2017-11-20

We report a new topological phononic crystal in a ring-waveguide acoustic system. In the previous reports on topological phononic crystals, there are two types of topological phases: quantum Hall phase and quantum spin Hall phase. A key point in achieving quantum Hall insulator is to break the time-reversal (TR) symmetry, and for quantum spin Hall insulator, the construction of pseudo-spin is necessary. We build such pseudo-spin states under particular crystalline symmetry (C-6v) and then break the degeneracy of the pseudo-spin states by introducing airflow to the ring. We study the topology evolution by changing both the geometric parameters of the unit cell and the strength of the applied airflow. We find that the system exhibits three phases: quantum spin Hall phase, conventional insulator phase and a new quantum anomalous Hall phase.

A TECHNIQUE OF IDENTIFICATION OF THE PHASE-DISPLACEMENT GROUP OF THREE-PHASE TRANSFORMER

International Nuclear Information System (INIS)

Aburjania, A.; Begiashvili, V.; Rezan Turan

2007-01-01

It is demonstrated that the arbitrary choice of arbitrarily pisitive direction of induced currents and voltages contradicts the energy conservation law and leads to equilibrium equations and standards making no sense from the physical standpoint. Of 12 recognized standard phase-displacement groups of three-phase transformer, only three have real physical bases. The rest are based on a wrong assumption about mutual biasing of primary and secondary currents. They does not rule out the occurrence of emergency situations and, thus, must be eliminated from use. A new method of identification of the phase-displacement of three-phase transformer is proposed. The method is based on well-known physical laws with consideration for the dual character of the inertia of mutual inductance and exhausts for all possible versions of connection of transformer windings. (author)

N Springs expedited response action proposal

Energy Technology Data Exchange (ETDEWEB)

1994-01-01

Since signing the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) in 1989, the parties to the agreement have recognized the need to modify the approach to conducting investigations, studies, and cleanup actions at Hanford. To implement this approach, the parties have jointly developed the Hanford Past-Practice Strategy. The strategy defines a non-time-critical expedited response action (ERA) as a response action ``needed to abate a threat to human health or welfare or the environment where sufficient time exists for formal planning prior to initiation of response. In accordance with the past-practice strategy, DOE proposes to conduct an ERA at the N Springs, located in the Hanford 100 N Area, to substantially reduce the strontium-90 transport into the river through the groundwater pathway. The purpose of this ERA proposal is to provide sufficient information to select a preferred alternative at N Springs. The nature of an ERA requires that alternatives developed for the ERA be field ready; therefore, all the technologies proposed for the ERA should be capable of addressing the circumstances at N Springs. A comparison of these alternatives is made based on protectiveness, cost, technical feasibility, and institutional considerations to arrive at a preferred alternative. Following the selection of an alternative, a design phase will be conducted; the design phase will include a detailed look at design parameters, performance specifications, and costs of the selected alternative. Testing will be conducted as required to generate design data.

A simple image-reject mixer based on two parallel phase modulators

Science.gov (United States)

Hu, Dapeng; Zhao, Shanghong; Zhu, Zihang; Li, Xuan; Qu, Kun; Lin, Tao; Zhang, Kun

2018-02-01

A simple photonic microwave image-reject mixer (IRM) using two parallel phase modulators is proposed. First, a photonic microwave mixer with phase shift ability is achieved using two parallel phase modulators (PMs), an optical bandpass filter, three polarization controllers, three polarization beam splitters and two balanced photodetectors. At the output of the mixer, two frequency downconverted signals with tunable frequency difference can be obtained. By adjusting the phase difference as 90° and utilizing an electrical 90° hybrid, the useless components can be eliminated, and the image reject operation is realized. The key advantage of the proposed scheme is the usage of PM, which avoid the DC bias shifting problem and make the system simple and stable. A simulation is performed to verify the proposed scheme, a relative - 90° or 90° phase shift can be obtained between the two output ports of the photonic microwave mixer, at the output of the IRM, 60 dB image-reject ratio is obtained.

NASA SBIR abstracts of 1990 phase 1 projects

Science.gov (United States)

Schwenk, F. C.; Gilman, J. A.; Paige, J. B.

1991-01-01

The research objectives of the 280 projects placed under contract in the National Aeronautics and Space Administration (NASA) 1990 Small Business Innovation Research (SBIR) Phase 1 program are described. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses in response to NASA's 1990 SBIR Phase 1 Program Solicitation. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 280, in order of its appearance in the body of the report. The document also includes Appendixes to provide additional information about the SBIR program and permit cross-reference in the 1990 Phase 1 projects by company name, location by state, principal investigator, NASA field center responsible for management of each project, and NASA contract number.

Direct detection of metal-insulator phase transitions using the modified Backus-Gilbert method

Directory of Open Access Journals (Sweden)

Ulybyshev Maksim

2018-01-01

Full Text Available The detection of the (semimetal-insulator phase transition can be extremely difficult if the local order parameter which characterizes the ordered phase is unknown. In some cases, it is even impossible to define a local order parameter: the most prominent example of such system is the spin liquid state. This state was proposed to exist in the Hubbard model on the hexagonal lattice in a region between the semimetal phase and the antiferromagnetic insulator phase. The existence of this phase has been the subject of a long debate. In order to detect these exotic phases we must use alternative methods to those used for more familiar examples of spontaneous symmetry breaking. We have modified the Backus-Gilbert method of analytic continuation which was previously used in the calculation of the pion quasiparticle mass in lattice QCD. The modification of the method consists of the introduction of the Tikhonov regularization scheme which was used to treat the ill-conditioned kernel. This modified Backus-Gilbert method is applied to the Euclidean propagators in momentum space calculated using the hybrid Monte Carlo algorithm. In this way, it is possible to reconstruct the full dispersion relation and to estimate the mass gap, which is a direct signal of the transition to the insulating state. We demonstrate the utility of this method in our calculations for the Hubbard model on the hexagonal lattice. We also apply the method to the metal-insulator phase transition in the Hubbard-Coulomb model on the square lattice.

Distinction between added-energy and phase-resetting mechanisms in non-invasively detected somatosensory evoked responses.

Science.gov (United States)

Fedele, T; Scheer, H-J; Burghoff, M; Waterstraat, G; Nikulin, V V; Curio, G

2013-01-01

Non-invasively recorded averaged event-related potentials (ERP) represent a convenient opportunity to investigate human brain perceptive and cognitive processes. Nevertheless, generative ERP mechanisms are still debated. Two previous approaches have been contested in the past: the added-energy model in which the response raises independently from the ongoing background activity, and the phase-reset model, based on stimulus-driven synchronization of oscillatory ongoing activity. Many criteria for the distinction of these two models have been proposed, but there is no definitive methodology to disentangle them, owing also to the limited information at the single trial level. Here, we propose a new approach combining low-noise EEG technology and multivariate decomposition techniques. We present theoretical analyses based on simulated data and identify in high-frequency somatosensory evoked responses an optimal target for the distinction between the two mechanisms.

Work plan for phase 1A paleochannel studies at the Cheney disposal cell, Grand Junction, Colorado: Draft

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-11-01

This document will serve as a Work Plan for continuing paleochannel characterization activities at the Cheney disposal site near Grand Junction, Colorado. Elevated levels of nitrate were encountered in ground water from two monitor wells installed in alluvial paleochannels near the Cheney disposal cell in 1994. This triggered a series of investigations (Phase 1) designed to determine the source of nitrate and other chemical constituents in ground water at the site. A comprehensive summary of the Phase 1 field investigations (limited to passive monitoring and modeling studies) conducted by the Remedial Action Contractor (RAC) and Technical Assistance Contractor (TAC) to date is provided in Section 2.0 of this document. Results of Phase 1 were inconclusive regarding the potential interaction between the disposal cell and the paleochannels, so additional Phase 1A investigations are planned. Recommendations for Phase 1A tasks and possible future activities are discussed in Section 3.0. Detailed information on the implementation of the proposed Phase 1A tasks appears in Section 4.0 and will provide the basis for Statements of Work (SOW) for each of these tasks. A detailed sampling plan is provided to ensure quality and a consistency with previous data collection efforts.

Work plan for phase 1A paleochannel studies at the Cheney disposal cell, Grand Junction, Colorado: Draft

International Nuclear Information System (INIS)

1996-11-01

This document will serve as a Work Plan for continuing paleochannel characterization activities at the Cheney disposal site near Grand Junction, Colorado. Elevated levels of nitrate were encountered in ground water from two monitor wells installed in alluvial paleochannels near the Cheney disposal cell in 1994. This triggered a series of investigations (Phase 1) designed to determine the source of nitrate and other chemical constituents in ground water at the site. A comprehensive summary of the Phase 1 field investigations (limited to passive monitoring and modeling studies) conducted by the Remedial Action Contractor (RAC) and Technical Assistance Contractor (TAC) to date is provided in Section 2.0 of this document. Results of Phase 1 were inconclusive regarding the potential interaction between the disposal cell and the paleochannels, so additional Phase 1A investigations are planned. Recommendations for Phase 1A tasks and possible future activities are discussed in Section 3.0. Detailed information on the implementation of the proposed Phase 1A tasks appears in Section 4.0 and will provide the basis for Statements of Work (SOW) for each of these tasks. A detailed sampling plan is provided to ensure quality and a consistency with previous data collection efforts

Power sharing algorithm for vector controlled six-phase AC motor with four customary three-phase voltage source inverter drive

Directory of Open Access Journals (Sweden)

Sanjeevikumar Padmanaban

2015-09-01

Full Text Available This paper considered a six-phase (asymmetrical induction motor, kept 30° phase displacement between two set of three-phase open-end stator windings configuration. The drive system consists of four classical three-phase voltage inverters (VSIs and all four dc sources are deliberately kept isolated. Therefore, zero-sequence/homopolar current components cannot flow. The original and effective power sharing algorithm is proposed in this paper with three variables (degree of freedom based on synchronous field oriented control (FOC. A standard three-level space vector pulse width modulation (SVPWM by nearest three vectors (NTVs approach is adopted to regulate each couple of VSIs. The proposed power sharing algorithm is verified by complete numerical simulation modeling (Matlab/Simulink-PLECS software of whole ac drive system by observing the dynamic behaviors in different designed condition. Set of results are provided in this paper, which confirms a good agreement with theoretical development.

Proposal and Validation of an Entrepreneur Competency Profile: Implications for Education

Science.gov (United States)

Alda-Varas, Rodrigo; Villardon-Gallego, Lourdes; Elexpuru-Albizuri, Itziar

2012-01-01

Introduction: This research presents the validated proposal of an entrepreneur competency profile. We analyzed the phases of the entrepreneurial process, and the functions involved in each of them, in order to identify the tasks involved in each function/role and consequently the specific competencies of entrepreneurs. Method: The proposal was…

Blind Estimation of the Phase and Carrier Frequency Offsets for LDPC-Coded Systems

Directory of Open Access Journals (Sweden)

Houcke Sebastien

2010-01-01

Full Text Available Abstract We consider in this paper the problem of phase offset and Carrier Frequency Offset (CFO estimation for Low-Density Parity-Check (LDPC coded systems. We propose new blind estimation techniques based on the calculation and minimization of functions of the Log-Likelihood Ratios (LLR of the syndrome elements obtained according to the parity check matrix of the error-correcting code. In the first part of this paper, we consider phase offset estimation for a Binary Phase Shift Keying (BPSK modulation and propose a novel estimation technique. Simulation results show that the proposed method is very effective and outperforms many existing algorithms. Then, we modify the estimation criterion so that it can work for higher-order modulations. One interesting feature of the proposed algorithm when applied to high-order modulations is that the phase offset of the channel can be blindly estimated without any ambiguity. In the second part of the paper, we consider the problem of CFO estimation and propose estimation techniques that are based on the same concept as the ones presented for the phase offset estimation. The Mean Squared Error (MSE and Bit Error Rate (BER curves show the efficiency of the proposed estimation techniques.

High Performance Nanolauncher, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The proposed Low Cost Nanolauncher (LCN) is an upper stage using a new, inexpensive propulsion system. The Phase I program will combine several technologies with a...

Joint Carrier-Phase Synchronization and LDPC Decoding

Science.gov (United States)

Simon, Marvin; Valles, Esteban

2009-01-01

A method has been proposed to increase the degree of synchronization of a radio receiver with the phase of a suppressed carrier signal modulated with a binary- phase-shift-keying (BPSK) or quaternary- phase-shift-keying (QPSK) signal representing a low-density parity-check (LDPC) code. This method is an extended version of the method described in Using LDPC Code Constraints to Aid Recovery of Symbol Timing (NPO-43112), NASA Tech Briefs, Vol. 32, No. 10 (October 2008), page 54. Both methods and the receiver architectures in which they would be implemented belong to a class of timing- recovery methods and corresponding receiver architectures characterized as pilotless in that they do not require transmission and reception of pilot signals. The proposed method calls for the use of what is known in the art as soft decision feedback to remove the modulation from a replica of the incoming signal prior to feeding this replica to a phase-locked loop (PLL) or other carrier-tracking stage in the receiver. Soft decision feedback refers to suitably processed versions of intermediate results of iterative computations involved in the LDPC decoding process. Unlike a related prior method in which hard decision feedback (the final sequence of decoded symbols) is used to remove the modulation, the proposed method does not require estimation of the decoder error probability. In a basic digital implementation of the proposed method, the incoming signal (having carrier phase theta theta (sub c) plus noise would first be converted to inphase (I) and quadrature (Q) baseband signals by mixing it with I and Q signals at the carrier frequency [wc/(2 pi)] generated by a local oscillator. The resulting demodulated signals would be processed through one-symbol-period integrate and- dump filters, the outputs of which would be sampled and held, then multiplied by a soft-decision version of the baseband modulated signal. The resulting I and Q products consist of terms proportional to the cosine

7 CFR 3403.4 - Three-phase program.

Science.gov (United States)

2010-01-01

... SBIR Program funds. The purpose of the third phase is to pursue the commercial applications or objectives of the research carried out in Phases I and II through the use of private or Federal non-SBIR... proposals) to conduct feasibility-related experimental research and development related to described agency...

Emergence of Griffiths phase and glassy mixed phase in Sm0.5Ca0.5MnO3 nanomanganites

International Nuclear Information System (INIS)

Giri, S.K.; Yusuf, S.M.; Mukadam, M.D.; Nath, T.K.

2014-01-01

Graphical abstract: A detailed investigation on the effect of grain size on formation of Griffiths phase, and glassy mixed phase in CE-type antiferromagnetic Sm 0.5 Ca 0.5 MnO 3 manganite are carried out. A rigorous measurement of linear and non-linear ac magnetic susceptibilities, time dependent relaxation and aging phenomena in Sm 0.5 Ca 0.5 MnO 3 nanomanganite confirm the existence of a glassy mixed phase in the low temperature regime. The signature of Griffiths phase in nanosized manganite has been confirmed from the detailed ac and dc magnetization studies. The existence of Griffiths phase is verified through the anomalous behavior of the low field temperature dependent an inverse ac and dc magnetic susceptibility. Based on experimental results, the glassy phase of nanomanganites has been attributed to the phase separation effect and interaction between the ferromagnetic clusters. A phenomenological core/shell model has also been proposed based on the surface disorder to explain the observed Griffiths phase in these nanosized manganites. Fig. 1: (Left) The plot of inverse of ac susceptibility χ ac -1 measured at f = 1 Hz and H ac = 2 Oe as a function of temperature for S750 sample. Inset shows the same for S550 sample. (Right) A schematic of the proposed model to describe the magnetic state of the Sm 0.5 Ca 0.5 MnO 3 system at different average sizes. Highlights: • Effect of grain size on Griffiths phase and glassy mixed phase is discussed. • GP is confirmed by dc, linear and non-linear ac magnetization in nanomanganites. • Glassy mixed phase is discussed by time dependent relaxation and aging phenomena. • The existence of GP is verified through an inverse ac and dc magnetic susceptibility. • A phenomenological core/shell model has been proposed based on surface disorder. -- Abstract: A detailed investigation on the effect of grain size on formation of Griffiths phase (GP), and glassy mixed phase in CE-type antiferromagnetic Sm 0.5 Ca 0.5 MnO 3

High 15-F2t-Isoprostane Levels in Patients with a Previous History of Nonmelanoma Skin Cancer: The Effects of Supplementary Antioxidant Therapy

Directory of Open Access Journals (Sweden)

Betânia de Jesus e Silva de Almendra Freitas

2015-01-01

Full Text Available Background. Phase I of this study was aimed at comparing the profiles of oxidative stress biomarkers in patients with history of nonmelanoma skin cancer (NMSC, previously treated with surgery, to the healthy subjects. Phase II aimed to evaluate the effects of supplementary antioxidant therapy on the levels of biomarkers in the case group. Materials and Methods. In Phase I, oxidative stress biomarkers were measured in blood samples obtained from 24 healthy subjects and 60 patients with history of NMSC previously treated with surgery. In Phase II, the 60 patients with history of NMSC were randomized into two subgroups, one receiving placebo (n=34 and the other (n=26 receiving vitamin C, vitamin E, and zinc supplementation for 8 weeks, followed by reevaluation of biomarkers. Results. In Phase I, patients with history of NMSC showed increased plasma concentrations of all biomarkers, but only 15-F2t-isoprostane was significantly higher than in the healthy subjects. Risk of NMSC increased by 4% for each additional 1 pg/mL increase in 15-F2t-isoprostane. In Phase II, supplementation did not significantly reduce levels of oxidative stress biomarkers. Conclusion. Patients with history of NMSC had significantly high 15-F2t-isoprostane plasma levels; supplementation did not result in significant reduction of oxidative stress biomarkers. This trial was registered with ClinicalTrials.gov (ID NCT02248584.

Efficient Phase Locking of Fiber Amplifiers Using a Low-Cost and High-Damage-Threshold Phase Control System

International Nuclear Information System (INIS)

Pu, Zhou; Yan-Xing, Ma; Xiao-Lin, Wang; Hao-Tong, Ma; Xiao-Jun, Xu; Ze-Jin, Liu

2010-01-01

We propose a low-cost and high-damage-threshold phase control system that employs a piezoelectric ceramic transducer modulator controlled by a stochastic parallel gradient descent algorithm. Efficient phase locking of two fiber amplifiers is demonstrated. Experimental results show that energy encircled in the target pinhole is increased by a factor of 1.76 and the visibility of the fringe pattern is as high as 90% when the system is in close-loop. The phase control system has potential in phase locking of large-number and high-power fiber laser endeavors. (fundamental areas of phenomenology (including applications))

Cohesive phase-field fracture and a PDE constrained optimization approach to fracture inverse problems

Energy Technology Data Exchange (ETDEWEB)

Tupek, Michael R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-06-30

In recent years there has been a proliferation of modeling techniques for forward predictions of crack propagation in brittle materials, including: phase-field/gradient damage models, peridynamics, cohesive-zone models, and G/XFEM enrichment techniques. However, progress on the corresponding inverse problems has been relatively lacking. Taking advantage of key features of existing modeling approaches, we propose a parabolic regularization of Barenblatt cohesive models which borrows extensively from previous phase-field and gradient damage formulations. An efficient explicit time integration strategy for this type of nonlocal fracture model is then proposed and justified. In addition, we present a C++ computational framework for computing in- put parameter sensitivities efficiently for explicit dynamic problems using the adjoint method. This capability allows for solving inverse problems involving crack propagation to answer interesting engineering questions such as: 1) what is the optimal design topology and material placement for a heterogeneous structure to maximize fracture resistance, 2) what loads must have been applied to a structure for it to have failed in an observed way, 3) what are the existing cracks in a structure given various experimental observations, etc. In this work, we focus on the first of these engineering questions and demonstrate a capability to automatically and efficiently compute optimal designs intended to minimize crack propagation in structures.

Dynamics Assessment of Advanced Single-Phase PLL Structures

DEFF Research Database (Denmark)

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

2013-01-01

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

Traveling wave accelerating structures with a large phase advance

International Nuclear Information System (INIS)

Paramonov, V.V.

2012-01-01

The cells RF parameters for the well known Disk Loaded Waveguide (DLW) are considered in higher pass bands of TM01 wave, providing operating phase advance between 180 o - 1230 o per cell. With an appropriate shape optimization and some additional elements proposed traveling wave structures with such large phase advance overlap the classical first band DLW in RF efficiency. Examples of proposed structures together with RF and dispersion properties are presented.

Constitutive model for a stress- and thermal-induced phase transition in a shape memory polymer

International Nuclear Information System (INIS)

Guo, Xiaogang; Liu, Liwu; Liu, Yanju; Zhou, Bo; Leng, Jinsong

2014-01-01

Recently, increasing applications of shape memory polymers have pushed forward the development of appropriate constitutive models for smart materials such as the shape memory polymer. During the heating process, the phase transition, which is a continuous time-dependent process, happens in the shape memory polymer, and various individual phases will form at different configuration temperatures. In addition, these phases can generally be divided into two parts: the frozen and active phase (Liu Y et al 2006 Int. J. Plast. 22 279–313). During the heating or cooling process, the strain will be stored or released with the occurring phase transition between these two parts. Therefore, a shape memory effect emerges. In this paper, a new type of model was developed to characterize the variation of the volume fraction in a shape memory polymer during the phase transition. In addition to the temperature variation, the applied stress was also taken as a significant influence factor on the phase transition. Based on the experimental results, an exponential equation was proposed to describe the relationship between the stress and phase transition temperature. For the sake of describing the mechanical behaviors of the shape memory polymer, a three-dimensional constitutive model was established. Also, the storage strain, which was the key factor of the shape memory effect, was also discussed in detail. Similar to previous works, we first explored the effect of applied stress on storage strain. Through comparisons with the DMA and the creep experimental results, the rationality and accuracy of the new phase transition and constitutive model were finally verified. (paper)

Electrical transport and phase stability in silver iodide-cadmium iodide

International Nuclear Information System (INIS)

Brightwell, J.W.; Buckley, C.N.; Miller, L.S.; Ray, B.

1983-01-01

A form of the equilibrium diagram for the system AgI-CdI 2 is proposed on the basis of thermal, X-ray diffractometer, and electrical conductivity data. Only one intermediate equilibrium phase, of composition Ag 2 CdI 4 , of tetragonal form with a 0 = 6.35 A and c 0 = 12.7 A is apparent; the previously reported hexagonal form of this composition being metastable. Low levels of CdI 2 are found to enhance the formation of the cubic, #betta#-form, af AgI and to increase the electrical conductivity. For various levels of CdI 2 inclusion in AgI, the principal increase in conductivity occurs in the region of 110 0 C instead of at 146 0 C as in pure AgI. (author)

Simplified absolute phase retrieval of dual-frequency fringe patterns in fringe projection profilometry

Science.gov (United States)

Lu, Jin; Mo, Rong; Sun, Huibin; Chang, Zhiyong; Zhao, Xiaxia

2016-04-01

In fringe projection profilometry, a simplified method is proposed to recover absolute phase maps of two-frequency fringe patterns by using a unique mapping rule. The mapping rule is designed from the rounded phase values to the fringe order of each pixel. Absolute phase can be recovered by the fringe order maps. Unlike the existing techniques, where the lowest frequency of dual- or multiple-frequency fringe patterns must be single, the presented method breaks the limitation and simplifies the procedure of phase unwrapping. Additionally, due to many issues including ambient light, shadow, sharp edges, step height boundaries and surface reflectivity variations, a novel framework of automatically identifying and removing invalid phase values is also proposed. Simulations and experiments have been carried out to validate the performances of the proposed method.

Developing an energy design tool: Phase 1 report

Energy Technology Data Exchange (ETDEWEB)

Heidell, J.A.; Deringer, J.D.

1987-02-01

This report documents the planning phase of a proposed four-phase project for creating computer software to provide energy expertise in a manageable form to architects and engineers - thereby decreasing energy use in new buildings. The government sponsored software would be integrated with commercially developed software for use in the design of buildings. The result would be an integrated software package to aid the designer in the building design process and to provide expert insight into the energy related implications of a proposed design.

Preoperative screening: value of previous tests.

Science.gov (United States)

Macpherson, D S; Snow, R; Lofgren, R P

1990-12-15

To determine the frequency of tests done in the year before elective surgery that might substitute for preoperative screening tests and to determine the frequency of test results that change from a normal value to a value likely to alter perioperative management. Retrospective cohort analysis of computerized laboratory data (complete blood count, sodium, potassium, and creatinine levels, prothrombin time, and partial thromboplastin time). Urban tertiary care Veterans Affairs Hospital. Consecutive sample of 1109 patients who had elective surgery in 1988. At admission, 7549 preoperative tests were done, 47% of which duplicated tests performed in the previous year. Of 3096 previous results that were normal as defined by hospital reference range and done closest to the time of but before admission (median interval, 2 months), 13 (0.4%; 95% CI, 0.2% to 0.7%), repeat values were outside a range considered acceptable for surgery. Most of the abnormalities were predictable from the patient's history, and most were not noted in the medical record. Of 461 previous tests that were abnormal, 78 (17%; CI, 13% to 20%) repeat values at admission were outside a range considered acceptable for surgery (P less than 0.001, frequency of clinically important abnormalities of patients with normal previous results with those with abnormal previous results). Physicians evaluating patients preoperatively could safely substitute the previous test results analyzed in this study for preoperative screening tests if the previous tests are normal and no obvious indication for retesting is present.

Phases of kinky holographic nuclear matter

Energy Technology Data Exchange (ETDEWEB)

Elliot-Ripley, Matthew; Sutcliffe, Paul; Zamaklar, Marija [Department of Mathematical Sciences, Durham University,South Road, Durham (United Kingdom)

2016-10-17

Holographic QCD at finite baryon number density and zero temperature is studied within the five-dimensional Sakai-Sugimoto model. We introduce a new approximation that models a smeared crystal of solitonic baryons by assuming spatial homogeneity to obtain an effective kink theory in the holographic direction. The kink theory correctly reproduces a first order phase transition to lightly bound nuclear matter. As the density is further increased the kink splits into a pair of half-kink constituents, providing a concrete realization of the previously suggested dyonic salt phase, where the bulk soliton splits into constituents at high density. The kink model also captures the phenomenon of baryonic popcorn, in which a first order phase transition generates an additional soliton layer in the holographic direction. We find that this popcorn transition takes place at a density below the dyonic salt phase, making the latter energetically unfavourable. However, the kink model predicts only one pop, rather than the sequence of pops suggested by previous approximations. In the kink model the two layers produced by the single pop form the surface of a soliton bag that increases in size as the baryon chemical potential is increased. The interior of the bag is filled with abelian electric potential and the instanton charge density is localized on the surface of the bag. The soliton bag may provide a holographic description of a quarkyonic phase.

Cosmological phase transitions

International Nuclear Information System (INIS)

Kolb, E.W.

1987-01-01

If the universe stated from conditions of high temperature and density, there should have been a series of phase transitions associated with spontaneous symmetry breaking. The cosmological phase transitions could have observable consequences in the present Universe. Some of the consequences including the formation of topological defects and cosmological inflation are reviewed here. One of the most important tools in building particle physics models is the use of spontaneous symmetry breaking (SSB). The proposal that there are underlying symmetries of nature that are not manifest in the vacuum is a crucial link in the unification of forces. Of particular interest for cosmology is the expectation that are the high temperatures of the big bang symmetries broken today will be restored, and that there are phase transitions to the broken state. The possibility that topological defects will be produced in the transition is the subject of this section. The possibility that the Universe will undergo inflation in a phase transition will be the subject of the next section. Before discussing the creation of topological defects in the phase transition, some general aspects of high-temperature restoration of symmetry and the development of the phase transition will be reviewed. 29 references, 1 figure, 1 table

Experimental demonstration of continuous variable cloning with phase-conjugate inputs

DEFF Research Database (Denmark)

Sabuncu, Metin; Andersen, Ulrik Lund; Leuchs, G.

2007-01-01

We report the first experimental demonstration of continuous variable cloning of phase-conjugate coherent states as proposed by Cerf and Iblisdir [Phys. Rev. Lett. 87, 247903 (2001)]. In contrast to this proposal, the cloning transformation is accomplished using only linear optical components......, homodyne detection, and feedforward. As a result of combining phase conjugation with a joint measurement strategy, superior cloning is demonstrated with cloning fidelities reaching 89%....

Synthesis Of Ultrasound Field Sources Based on Phase Screen Approximation

Directory of Open Access Journals (Sweden)

Sukhanov Dmitry

2018-01-01

Full Text Available Here is proposed the method for synthesizing the sources of an acoustic field on the basis of an approximation of the phase screen. The technology of manufacturing ultrasonic phased arrays providing the formation of a field of a given distribution is proposed. An experimental setup has been developed for the formation of a vortex field at a distance of 10 cm.

Potential benefits of saturation cycle with two-phase refrigerant injection

International Nuclear Information System (INIS)

Lee, Hoseong; Hwang, Yunho; Radermacher, Reinhard; Chun, Ho-Hwan

2013-01-01

In this paper, a saturation cycle is proposed to enhance a vapor compression cycle performance by reducing thermodynamic losses associated with single phase gas compression and isenthalpic expansion. In order to approach the saturation cycle, a two-phase refrigerant injection technique is applied to the multi-stage cycle. This multi-stage cycle with different options is modeled, and its performance is evaluated under ASHRAE standard operating conditions for air conditioning systems. Moreover, the two-phase refrigerant injection cycle is compared with the typical vapor injection cycle which is utilizing the internal heat exchanger or the flash tank. Low GWP refrigerants are applied to this two-phase refrigerant injection cycle. In terms of the COP and its improvement, R123 has a higher potential than any other refrigerants in the multi-stage cycle. Lastly, practical ideas realizing the saturation cycle are discussed such as multi-stage phase separator, phase separator with helical structure inside, and injection location of the compressor. -- Highlights: • A saturation cycle is proposed to enhance the vapor compression cycle performance. • Two-phase refrigerant injection technique is applied to the multi-stage cycle. • Modeling results of the proposed cycle show the significant performance improvement. • Low GWP refrigerants are applied and R123 shows the highest performance. • New parameters, α and ε, are used to show the potential of the saturation cycle

Facile preparation of an alternating copolymer-based high molecular shape-selective organic phase for reversed-phase liquid chromatography.

Science.gov (United States)

Mallik, Abul K; Noguchi, Hiroki; Rahman, Mohammed Mizanur; Takafuji, Makoto; Ihara, Hirotaka

2018-06-22

The synthesis of a new alternating copolymer-grafted silica phase is described for the separation of shape-constrained isomers of polycyclic aromatic hydrocarbons (PAHs) and tocopherols in reversed-phase high-performance liquid chromatography (RP-HPLC). Telomerization of the monomers (octadecyl acrylate and N-methylmaleimide) was carried out with a silane coupling agent; 3-mercaptopropyltrimethoxysilane (MPS), and the telomer (T) was grafted onto porous silica surface to prepare the alternating copolymer-grafted silica phase (Sil-alt-T). The new hybrid material was characterized by elemental analyses, diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, and solid-state 13 C and 29 Si cross-polarization magic-angle spinning (CP/MAS) NMR spectroscopy. The results of 13 C CP/MAS NMR demonstrated that the alkyl chains of the grafted polymers in Sil-alt-T remained disordered, amorphous, and mobile represented by gauche conformational form. Separation abilities and molecular-shape selectivities of the prepared organic phase were evaluated by the separation of PAHs isomers and Standard Reference Material 869b, Column Selectivity Test Mixture for Liquid Chromatography, respectively and compared with commercially available octadecylsilylated silica (ODS) and C 30 columns as well as previously reported alternating copolymer-based column. The effectiveness of this phase is also demonstrated by the separation of tocopherol isomers. Oriented functional groups along the polymer main chains and cavity formations are investigated to be the driving force for better separation with multiple-interactions with the solutes. One of the advantages of the Sil-alt-T phase to that of the previously reported phase is the synthesis of the telomer first and then immobilized onto silica surface. In this case, the telomer was characterized easily with simple spectroscopic techniques and the molecular mass and polydispersity index of the telomer were determined by size exclusion

A Phase Vocoder Based on Nonstationary Gabor Frames

DEFF Research Database (Denmark)

Ottosen, Emil Solsbæk; Dörfler, Monika

2017-01-01

We propose a new algorithm for time stretching music signals based on the theory of nonstationary Gabor frames (NSGFs). The algorithm extends the techniques of the classical phase vocoder (PV) by incorporating adaptive timefrequency (TF) representations and adaptive phase locking. The adaptive TF...

Novel, Four-Switch, Z-Source Three-Phase Inverter

DEFF Research Database (Denmark)

Antal, Robert; Muntean, Nicolae; Boldea, Ion

2010-01-01

This paper presents a new z-source three phase inverter topology. The proposed topology combines the advantages of a traditional four-switch three-phase inverter with the advantages of the z impedance network (one front-end diode, two inductors and two X connected capacitors). This new topology......, besides the self-boost property, has low switch count and it can operate as a buck-boost inverter. In contrast to standard four-switch three-phase inverter which operates at half dc input voltage the proposed four-switch z-source inverter, by self boosting, brings the output voltage at same (or higher......) value as in six switch standard three-phase inverter. The article presents the derivation of the equations describing the operation of the converter based on space vector analysis, validation through digital simulations in PSIM and preliminary experimental results on a laboratory setup with a dsPIC30F...

A Phase Vocoder Based on Nonstationary Gabor Frames

DEFF Research Database (Denmark)

Ottosen, Emil Solsbæk; Dörfler, Monika

2017-01-01

We propose a new algorithm for time stretching music signals based on the theory of nonstationary Gabor frames (NSGFs). The algorithm extends the techniques of the classical phase vocoder (PV) by incorporating adaptive timefrequency (TF) representations and adaptive phase locking. The adaptive TF...... representations imply good time resolution for the onsets of attack transients and good frequency resolution for the sinusoidal components. We estimate the phase values only at peak channels and the remaining phases are then locked to the values of the peaks in an adaptive manner. During attack transients we keep...... that with just three times as many TF coefficients as signal samples, artifacts such as phasiness and transient smearing can be greatly reduced compared to the classical PV. The proposed algorithm is tested on both synthetic and real world signals and compared with state of the art algorithms in a reproducible...

A general theory of interference fringes in x-ray phase grating imaging

International Nuclear Information System (INIS)

Yan, Aimin; Wu, Xizeng; Liu, Hong

2015-01-01

Purpose: The authors note that the concept of the Talbot self-image distance in x-ray phase grating interferometry is indeed not well defined for polychromatic x-rays, because both the grating phase shift and the fractional Talbot distances are all x-ray wavelength-dependent. For x-ray interferometry optimization, there is a need for a quantitative theory that is able to predict if a good intensity modulation is attainable at a given grating-to-detector distance. In this work, the authors set out to meet this need. Methods: In order to apply Fourier analysis directly to the intensity fringe patterns of two-dimensional and one-dimensional phase grating interferometers, the authors start their derivation from a general phase space theory of x-ray phase-contrast imaging. Unlike previous Fourier analyses, the authors evolved the Wigner distribution to obtain closed-form expressions of the Fourier coefficients of the intensity fringes for any grating-to-detector distance, even if it is not a fractional Talbot distance. Results: The developed theory determines the visibility of any diffraction order as a function of the grating-to-detector distance, the phase shift of the grating, and the x-ray spectrum. The authors demonstrate that the visibilities of diffraction orders can serve as the indicators of the underlying interference intensity modulation. Applying the theory to the conventional and inverse geometry configurations of single-grating interferometers, the authors demonstrated that the proposed theory provides a quantitative tool for the grating interferometer optimization with or without the Talbot-distance constraints. Conclusions: In this work, the authors developed a novel theory of the interference intensity fringes in phase grating x-ray interferometry. This theory provides a quantitative tool in design optimization of phase grating x-ray interferometers

A general theory of interference fringes in x-ray phase grating imaging.

Science.gov (United States)

Yan, Aimin; Wu, Xizeng; Liu, Hong

2015-06-01

The authors note that the concept of the Talbot self-image distance in x-ray phase grating interferometry is indeed not well defined for polychromatic x-rays, because both the grating phase shift and the fractional Talbot distances are all x-ray wavelength-dependent. For x-ray interferometry optimization, there is a need for a quantitative theory that is able to predict if a good intensity modulation is attainable at a given grating-to-detector distance. In this work, the authors set out to meet this need. In order to apply Fourier analysis directly to the intensity fringe patterns of two-dimensional and one-dimensional phase grating interferometers, the authors start their derivation from a general phase space theory of x-ray phase-contrast imaging. Unlike previous Fourier analyses, the authors evolved the Wigner distribution to obtain closed-form expressions of the Fourier coefficients of the intensity fringes for any grating-to-detector distance, even if it is not a fractional Talbot distance. The developed theory determines the visibility of any diffraction order as a function of the grating-to-detector distance, the phase shift of the grating, and the x-ray spectrum. The authors demonstrate that the visibilities of diffraction orders can serve as the indicators of the underlying interference intensity modulation. Applying the theory to the conventional and inverse geometry configurations of single-grating interferometers, the authors demonstrated that the proposed theory provides a quantitative tool for the grating interferometer optimization with or without the Talbot-distance constraints. In this work, the authors developed a novel theory of the interference intensity fringes in phase grating x-ray interferometry. This theory provides a quantitative tool in design optimization of phase grating x-ray interferometers.

Optical image encryption based on phase retrieval combined with three-dimensional particle-like distribution

International Nuclear Information System (INIS)

Chen, Wen; Chen, Xudong; Sheppard, Colin J R

2012-01-01

We propose a new phase retrieval algorithm for optical image encryption in three-dimensional (3D) space. The two-dimensional (2D) plaintext is considered as a series of particles distributed in 3D space, and an iterative phase retrieval algorithm is developed to encrypt the series of particles into phase-only masks. The feasibility and effectiveness of the proposed method are demonstrated by a numerical experiment, and the advantages and security of the proposed optical cryptosystems are also analyzed and discussed. (paper)

Fundamental incorporation of the density change during melting of a confined phase change material

Science.gov (United States)

Hernández, Ernesto M.; Otero, José A.

2018-02-01

The modeling of thermal diffusion processes taking place in a phase change material presents a challenge when the dynamics of the phase transition is coupled to the mechanical properties of the container. Thermo-mechanical models have been developed by several authors, however, it will be shown that these models only explain the phase transition dynamics at low pressures when the density of each phase experiences negligible changes. In our proposal, a new energy-mass balance equation at the interface is derived and found to be a consequence of mass conservation. The density change experienced in each phase is predicted by the proposed formulation of the problem. Numerical and semi-analytical solutions to the proposed model are presented for an example on a high temperature phase change material. The solutions to the models presented by other authors are observed to be well-behaved close to the isobaric limit. However, compared to the results obtained from our model, the change in the fusion temperature, latent heat, and absolute pressure is found to be greatly overestimated by other proposals when the phase transition is studied close to the isochoric regime.

Fiber Optic Microcantilever Sensor Coupled with Reactive Polymers for Vapor Phase Detection of Ammonia, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Luna Innovations proposes to adapt its current aqueous-based, fiber-optic microcantilever sensor technology for real-time, monitoring of ammonia in air. Phase I...

Reclaimable Thermally Reversible Polymers for AM Feedstock, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — CRG proposes to continue efforts from the 2016 NASA SBIR Phase I topic H5.04 Reclaimable Thermally Reversible Polymers for AM Feedstock. In Phase II, CRG will refine...

Thermal stability and phase transformation of metastable phases in Zr-Nb

International Nuclear Information System (INIS)

Aurelio, G.; Fernandez Guillermet, Armando

2003-01-01

The lattice parameters of the bcc (β) and (Ω) phases occurring metastability in a series of Zr-rich Zr-Nb alloys have been determined at and above room temperature (TR) using neutron diffraction techniques. In the first place, the effect of temperature changes upon the lattice parameters of the β and Ω phases in alloys with 10 and 18 at. % Nb was monitored using neutron thermo-diffraction. A method of analysis is applied to the data, which involve a confrontation between the observed structural properties and an idealized -or 'reference'- behavior (RB) which admits a simple mathematical description. A generalized form of the law of Vegard is adopted as RB for the β phase, whereas a specific RB is proposed for the Ω structure. The experimental data are well accounted for by this interpretation scheme, leading to a picture of the isothermal reactions occurring at high temperature, which involves the transfer of Nb from the Ω to the β phase. Finally, the neutron diffraction data on the Ω phase is combined with an electron microscopy study for the alloy with 10 at. % Nb aged at 773 K, which provides information on the composition of this phase and its evolution towards thermodynamic equilibrium. (author)

c-T phase diagram and Landau free energies of (AgAu)55 nanoalloy via neural-network molecular dynamic simulations.

Science.gov (United States)

Chiriki, Siva; Jindal, Shweta; Bulusu, Satya S

2017-10-21

For understanding the structure, dynamics, and thermal stability of (AgAu) 55 nanoalloys, knowledge of the composition-temperature (c-T) phase diagram is essential due to the explicit dependence of properties on composition and temperature. Experimentally, generating the phase diagrams is very challenging, and therefore theoretical insight is necessary. We use an artificial neural network potential for (AgAu) 55 nanoalloys. Predicted global minimum structures for pure gold and gold rich compositions are lower in energy compared to previous reports by density functional theory. The present work based on c-T phase diagram, surface area, surface charge, probability of isomers, and Landau free energies supports the enhancement of catalytic property of Ag-Au nanoalloys by incorporation of Ag up to 24% by composition in Au nanoparticles as found experimentally. The phase diagram shows that there is a coexistence temperature range of 70 K for Ag 28 Au 27 compared to all other compositions. We propose the power spectrum coefficients derived from spherical harmonics as an order parameter to calculate Landau free energies.

Precision phase estimation based on weak-value amplification

Science.gov (United States)

Qiu, Xiaodong; Xie, Linguo; Liu, Xiong; Luo, Lan; Li, Zhaoxue; Zhang, Zhiyou; Du, Jinglei

2017-02-01

In this letter, we propose a precision method for phase estimation based on the weak-value amplification (WVA) technique using a monochromatic light source. The anomalous WVA significantly suppresses the technical noise with respect to the intensity difference signal induced by the phase delay when the post-selection procedure comes into play. The phase measured precision of this method is proportional to the weak-value of a polarization operator in the experimental range. Our results compete well with the wide spectrum light phase weak measurements and outperform the standard homodyne phase detection technique.

Optimization of the superconducting phase of hydrogen sulfide

Science.gov (United States)

Degtyarenko, N. N.; Masur, E. A.

2015-12-01

The electron and phonon spectra, as well as the densities of electron and phonon states of the SH3 phase and the stable orthorhombic structure of hydrogen sulfide SH2, are calculated for the pressure interval 100-225 GPa. It is found that the I4/ mmm phase can be responsible for the superconducting properties of metallic hydrogen sulfide along with the SH3 phase. Sequential stages for obtaining and conservation of the SH2 phase are proposed. The properties of two (SH2 and SH3) superconducting phases of hydrogen sulfide are compared.

Power sharing algorithm for vector controlled six-phase AC motor with four customary three-phase voltage source inverter drive

DEFF Research Database (Denmark)

Padmanaban, Sanjeevikumar; Grandi, Gabriele; Blaabjerg, Frede

2015-01-01

This paper considered a six-phase (asymmetrical) induction motor, kept 30 phase displacement between two set of three-phase open-end stator windings configuration. The drive system consists of four classical three-phase voltage inverters (VSIs) and all four dc sources are deliberately kept isolated......) by nearest three vectors (NTVs) approach is adopted to regulate each couple of VSIs. The proposed power sharing algorithm is verified by complete numerical simulation modeling (Matlab/ Simulink-PLECS software) of whole ac drive system by observing the dynamic behaviors in different designed condition. Set...

Evaluating a proposed apprach for managing collaborative design in the conceptual design phase

NARCIS (Netherlands)

Sebastian, R.

2006-01-01

This paper evaluates the findings of prior research on managing collaborative design in the conceptual design phase of a building project. The prior research was explorative. It used several building projects in the Netherlands as case studies - De Resident in The Hague, Nieuw Stadshart in Almere,

Quantum disentanglement and phase measurements

International Nuclear Information System (INIS)

Buzek, V.; Hillery, M.

1995-01-01

A 50:50 beam splitter disentangles a two-mode squeezed vacuum state into two single-mode squeezed vacuum states. With the proper choice of parameters these two single-mode states will be identical. If one is passed through a device which shifts its phase, then the phases of the shifted and reference (unshifted) modes can be determined by the Vogel-Schleich technique. In this way the phase difference, i.e. the phase shift, can be measured to an accuracy of 1/N, where N is the total number of photons coming into the beam splitter. An improved scheme is also proposed involving the disentanglement of a shifted two-mode squeezed vacuum state. This leads to two shifted squeezed vacuum states at the output of the beam splitter. If one of these is passed through the phase shifter, then by performing homodyne measurements on the shifted and unshifted modes the phase shift can again be determined to an accuracy of 1/N. (author) 4 figs., 14 refs

Gravitationally self-induced phase transition

International Nuclear Information System (INIS)

Novello, M.; Duque, S.L.S.

1990-01-01

We propose a new mechanism by means of which a phase transition can be stimulated by self-gravitating matter. We suggest that this model could be used to explain the observed isotropy of the Universe. (orig.)

Non-cyclic phases for neutrino oscillations in quantum field theory

International Nuclear Information System (INIS)

Blasone, Massimo; Capolupo, Antonio; Celeghini, Enrico; Vitiello, Giuseppe

2009-01-01

We show the presence of non-cyclic phases for oscillating neutrinos in the context of quantum field theory. Such phases carry information about the non-perturbative vacuum structure associated with the field mixing. By subtracting the condensate contribution of the flavor vacuum, the previously studied quantum mechanics geometric phase is recovered.

Encyclopedia of two-phase heat transfer and flow IV modeling methodologies, boiling of CO₂, and micro-two-phase cooling

CERN Document Server

2018-01-01

Set IV is a new addition to the previous Sets I, II and III. It contains 23 invited chapters from international specialists on the topics of numerical modeling of pulsating heat pipes and of slug flows with evaporation; lattice Boltzmann modeling of pool boiling; fundamentals of boiling in microchannels and microfin tubes, CO2 and nanofluids; testing and modeling of micro-two-phase cooling systems for electronics; and various special topics (flow separation in microfluidics, two-phase sensors, wetting of anisotropic surfaces, ultra-compact heat exchangers, etc.). The invited authors are leading university researchers and well-known engineers from leading corporate research laboratories (ABB, IBM, Nokia Bell Labs). Numerous "must read" chapters are also included here for the two-phase community. Set IV constitutes a "must have" engineering and research reference together with previous Sets I, II and III for thermal engineering researchers and practitioners.

75 FR 60435 - Proposed Collection; Comment Request

Science.gov (United States)

2010-09-30

..., including through the use of automated collection techniques or other forms of information technology. DATES... 3502(c)(2)(A) of the Paperwork Reduction Act of 1995, the Chief of Naval Education and Training announces a proposed extension of a previously approved public information collection and seeks public...

High-pressure phase transition in silicon carbide under shock loading using ultrafast x-ray diffraction

Science.gov (United States)

Tracy, S. J.; Smith, R. F.; Wicks, J. K.; Fratanduono, D. E.; Gleason, A. E.; Bolme, C.; Speziale, S.; Appel, K.; Prakapenka, V. B.; Fernandez Panella, A.; Lee, H. J.; MacKinnon, A.; Eggert, J.; Duffy, T. S.

2017-12-01

The behavior of silicon carbide (SiC) under shock loading was investigated through a series of time-resolved pump-probe x-ray diffraction (XRD) measurements. SiC is found at impact sites and has been put forward as a possible constituent in the proposed class of extra-solar planets known as carbon planets. Previous studies have used wave profile measurements to identify a phase transition under shock loading near 1 Mbar, but crystal structure information was not obtained. We have carried out an in situ XRD study of shock-compressed SiC using the Matter in Extreme Conditions instrument of the Linac Coherent Light Source. The femtosecond time resolution of the x-ray free electron laser allows for the determination of time-dependent atomic arrangements during shock loading and release. Two high-powered lasers were used to generate ablation-driven compression waves in the samples. Time scans were performed using the same drive conditions and nominally identical targets. For each shot in a scan, XRD data was collected at a different probe time after the shock had entered the SiC. Probe times extended up to 40 ns after release. Scans were carried out for peak pressures of 120 and 185 GPa. Our results demonstrate that SiC transforms directly from the ambient tetrahedrally-coordinated phase to the octahedral B1 structure on the nanosecond timescale of laser-drive experiments and reverts to the tetrahedrally coordinated ambient phase within nanoseconds of release. The data collected at 120 GPa exhibit diffraction peaks from both compressed ambient phase and transformed B1 phase, while the data at 185 GPa show a complete transformation to the B1 phase. Densities determined from XRD peaks are in agreement with an extrapolation of previous continuum data as well as theoretical predictions. Additionally, a high degree of texture was retained in both the high-pressure phase as well as on back transformation. Two-dimensional fits to the XRD data reveal details of the

Multilevel modeling of micromechanics and phase formation for microstructural evolution of magnetic zones

International Nuclear Information System (INIS)

Suwa, Yoshihiro; Aizawa, Tatsuhiko; Takaya, Shigeru; Nagae, Yuji; Aoto, Kazumi

2005-03-01

The present research aims at a proposal of theoretical treatise to describe the local phase transformation from austenite to ferrite in the stainless steels under hot cyclic fatigue conditions. In experiments, this local phase transformation is detected as a magnetized region in the non-magnetic matrix after low-cycle fatigue test at the elevated temperature. The theoretical frame proposed here is composed of two methodologies. In the first approach, microstructure evolution with γ → α transformation is described by the phase field method. In the second approach, micromechanical method on the basis of the unit cell modeling is proposed to develop a new micromechanical analysis. The details of two approached are summarized in the following. (1) Phase formation simulation by the phase field method. Most of reports have started that γ-α phase transformation as a creep damage is induced by dechromization, which comes from carbide precipitation around grain boundaries. A new theoretical treatise is proposed for simulating this γ → α transformation in Fe-Cr-Ni system. Stabilities of both phases are investigated for various chemical compositions. Furthermore, in order to investigate dechromization phenomena in Fe-Cr-Ni-C system, a new theoretical frame is also proposed to handle an interstitial element in phase field method. (2) Low cycle fatigue elasto-plastic analysis by the unit-cell modeling. In experiments, the magnetized zones are generated to distribute at the vicinity of the hard, delta-phase inclusion in the austenitic matrix. The cumulative plastic region advances in the surroundings of this hard inclusion with increasing the number of cycles in the controlled strain range. This predicted profile of cumulative plastic regions corresponds to the experimentally measured, magnetized zones. In addition, the effect of geometric configuration of this inclusion on the plastic region evolution has close relationship of creep damage advancement in experiments

Simultaneous estimation of multiple phases in digital holographic interferometry using state space analysis

Science.gov (United States)

Kulkarni, Rishikesh; Rastogi, Pramod

2018-05-01

A new approach is proposed for the multiple phase estimation from a multicomponent exponential phase signal recorded in multi-beam digital holographic interferometry. It is capable of providing multidimensional measurements in a simultaneous manner from a single recording of the exponential phase signal encoding multiple phases. Each phase within a small window around each pixel is appproximated with a first order polynomial function of spatial coordinates. The problem of accurate estimation of polynomial coefficients, and in turn the unwrapped phases, is formulated as a state space analysis wherein the coefficients and signal amplitudes are set as the elements of a state vector. The state estimation is performed using the extended Kalman filter. An amplitude discrimination criterion is utilized in order to unambiguously estimate the coefficients associated with the individual signal components. The performance of proposed method is stable over a wide range of the ratio of signal amplitudes. The pixelwise phase estimation approach of the proposed method allows it to handle the fringe patterns that may contain invalid regions.

Quantitative measurement of phase variation amplitude of ultrasonic diffraction grating based on diffraction spectral analysis

Energy Technology Data Exchange (ETDEWEB)

Pan, Meiyan, E-mail: yphantomohive@gmail.com; Zeng, Yingzhi; Huang, Zuohua, E-mail: zuohuah@163.com [Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou, Guangdong 510006 (China)

2014-09-15

A new method based on diffraction spectral analysis is proposed for the quantitative measurement of the phase variation amplitude of an ultrasonic diffraction grating. For a traveling wave, the phase variation amplitude of the grating depends on the intensity of the zeroth- and first-order diffraction waves. By contrast, for a standing wave, this amplitude depends on the intensity of the zeroth-, first-, and second-order diffraction waves. The proposed method is verified experimentally. The measured phase variation amplitude ranges from 0 to 2π, with a relative error of approximately 5%. A nearly linear relation exists between the phase variation amplitude and driving voltage. Our proposed method can also be applied to ordinary sinusoidal phase grating.

AbobotulinumtoxinA Efficacy and Safety in Children With Equinus Foot Previously Treated With Botulinum Toxin.

Science.gov (United States)

Dabrowski, Edward; Bonikowski, Marcin; Gormley, Mark; Volteau, Magali; Picaut, Philippe; Delgado, Mauricio R

2018-05-01

The effects of botulinum toxin are transient, and repeat injections are required in children with lower-limb spasticity. However, the efficacy of botulinum toxin in patients who have received previous injections has remained largely unexplored. We present subgroup analyses of a phase III study conducted in ambulatory children (aged two to 17) with spastic equinus foot. Patients were randomized to single doses of abobotulinumtoxinA 10 U/kg/leg, 15 U/kg/leg, or placebo injected into the gastrocnemius-soleus complex (one or both legs). The first analysis was prespecified to review the effect of abobotulinumtoxinA in children previously treated with botulinum toxin versus those children new to the treatment; a second post hoc analysis evaluated the effect of abobotulinumtoxinA in children who changed botulinum toxin formulation. Of the 241 randomized patients, 113 had previously received botulinum toxin, including 86 who had been treated with another formulation. In both analyses, muscle tone (Modified Ashworth Scale) and the Physicians Global Assessment, at week 4, improved with abobotulinumtoxinA treatment versus placebo, regardless of baseline botulinum toxin status. Placebo responses in patients new to treatment were consistently higher than in the previously treated group. These results demonstrate similar abobotulinumtoxinA efficacy and safety profiles in children with spasticity who are new to botulinum toxin treatment and those children who were previously treated. The efficacy and safety of abobotulinumtoxinA treatment in these previously treated patients were comparable with the overall trial population, indicating that doses of 10 and 15 U/kg/leg are suitable starting doses for children with spasticity regardless of the previous botulinum toxin preparation used. Copyright © 2018 Elsevier Inc. All rights reserved.

Exploring the Proposed DSM-5 Criteria in a Clinical Sample

Science.gov (United States)

Taheri, Azin; Perry, Adrienne

2012-01-01

The proposed DSM-5 criteria for Autism Spectrum Disorder (ASD) depart substantially from the previous DSM-IV criteria. In this file review study of 131 children aged 2-12, previously diagnosed with either Autistic Disorder or Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS), 63% met the new DSM-5 ASD criteria, including 81%…

Efficient Phase Unwrapping Architecture for Digital Holographic Microscopy

Directory of Open Access Journals (Sweden)

Wen-Jyi Hwang

2011-09-01

Full Text Available This paper presents a novel phase unwrapping architecture for accelerating the computational speed of digital holographic microscopy (DHM. A fast Fourier transform (FFT based phase unwrapping algorithm providing a minimum squared error solution is adopted for hardware implementation because of its simplicity and robustness to noise. The proposed architecture is realized in a pipeline fashion to maximize through put of thecomputation. Moreover, the number of hardware multipliers and dividers are minimized to reduce the hardware costs. The proposed architecture is used as a custom user logic in a system on programmable chip (SOPC for physical performance measurement. Experimental results reveal that the proposed architecture is effective for expediting the computational speed while consuming low hardware resources for designing an embedded DHM system.

Two-phase framework for optimal multi-target Lambert rendezvous

OpenAIRE

Bang, Jun; Ahn, Jaemyung

2017-01-01

This paper proposes a two-phase framework to solve an optimal multi-target Lambert rendezvous problem. The first phase solves a series of single-target rendezvous problems for all departure-arrival object pairs to generate the elementary solutions, which provides candidate rendezvous trajectories (elementary solutions). The second phase formulates a variant of traveling salesman problem (TSP) using the elementary solutions prepared in the first phase and determines the best rendezvous sequenc...

Compositional modeling of three-phase flow with gravity using higher-order finite element methods

KAUST Repository

Moortgat, Joachim

2011-05-11

A wide range of applications in subsurface flow involve water, a nonaqueous phase liquid (NAPL) or oil, and a gas phase, such as air or CO2. The numerical simulation of such processes is computationally challenging and requires accurate compositional modeling of three-phase flow in porous media. In this work, we simulate for the first time three-phase compositional flow using higher-order finite element methods. Gravity poses complications in modeling multiphase processes because it drives countercurrent flow among phases. To resolve this issue, we propose a new method for the upwinding of three-phase mobilities. Numerical examples, related to enhanced oil recovery and carbon sequestration, are presented to illustrate the capabilities of the proposed algorithm. We pay special attention to challenges associated with gravitational instabilities and take into account compressibility and various phase behavior effects, including swelling, viscosity changes, and vaporization. We find that the proposed higher-order method can capture sharp solution discontinuities, yielding accurate predictions of phase boundaries arising in computational three-phase flow. This work sets the stage for a broad extension of the higher-order methods for numerical simulation of three-phase flow for complex geometries and processes.

Structural phase transitions in the ordered double perovskite Sr2MnTeO6

International Nuclear Information System (INIS)

Ortega-San Martin, L; Chapman, J P; Hernandez-Bocanegra, E; Insausti, M; Arriortua, M I; Rojo, T

2004-01-01

The crystal structure of the ordered double perovskite Sr 2 MnTeO 6 has been refined at ambient temperature from high resolution neutron and x-ray powder diffraction data in the monoclinic space group P 12 1 /n 1 with a 5.7009(1) A, b = 5.6770(1) A, c = 8.0334(1) A and β = 90.085(1) deg. This represents a combination of in-phase (+) and out-of-phase (-) rotations of virtually undistorted MnO 6 and TeO 6 octahedra in the (-+) sense about the axes of the ideal cubic perovskite. High temperature x-ray powder diffraction shows three structural phase transitions at approximately 250, 550 and 675 deg. C, each corresponding to the disappearance of rotations about one of these axes. The first transition was analysed by differential scanning calorimetry and showed a thermal hysteresis with an enthalpy of 0.55 J g -1 . We propose the (P12 1 /n1 → I12/m1 → I4/m → Fm3barm) sequence of structural transitions which has not been previously reported for a double perovskite oxide

Ibrutinib versus previous standard of care: an adjusted comparison in patients with relapsed/refractory chronic lymphocytic leukaemia.

Science.gov (United States)

Hansson, Lotta; Asklid, Anna; Diels, Joris; Eketorp-Sylvan, Sandra; Repits, Johanna; Søltoft, Frans; Jäger, Ulrich; Österborg, Anders

2017-10-01

This study explored the relative efficacy of ibrutinib versus previous standard-of-care treatments in relapsed/refractory patients with chronic lymphocytic leukaemia (CLL), using multivariate regression modelling to adjust for baseline prognostic factors. Individual patient data were collected from an observational Stockholm cohort of consecutive patients (n = 144) diagnosed with CLL between 2002 and 2013 who had received at least second-line treatment. Data were compared with results of the RESONATE clinical trial. A multivariate Cox proportional hazards regression model was used which estimated the hazard ratio (HR) of ibrutinib versus previous standard of care. The adjusted HR of ibrutinib versus the previous standard-of-care cohort was 0.15 (p ibrutinib in the RESONATE study were significantly longer than with previous standard-of-care regimens used in second or later lines in routine healthcare. The approach used, which must be interpreted with caution, compares patient-level data from a clinical trial with outcomes observed in a daily clinical practice and may complement results from randomised trials or provide preliminary wider comparative information until phase 3 data exist.

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.

All-optical WDM Regeneration of DPSK Signals using Optical Fourier Transformation and Phase Sensitive Amplification

DEFF Research Database (Denmark)

Guan, Pengyu; Røge, Kasper Meldgaard; Kjøller, Niels-Kristian

2015-01-01

We propose a novel all-optical WDM regeneration scheme for DPSK signals based on optical Fourier transformation and phase sensitive amplification. Phase regeneration of a WDM signal consisting of 4x10-Gbit/s phase noise degraded DPSK channels is demonstrated for the first time.......We propose a novel all-optical WDM regeneration scheme for DPSK signals based on optical Fourier transformation and phase sensitive amplification. Phase regeneration of a WDM signal consisting of 4x10-Gbit/s phase noise degraded DPSK channels is demonstrated for the first time....

76 FR 13340 - Agency Information Collection Activities: Proposed Collection; Comment Request-WIC Breastfeeding...

Science.gov (United States)

2011-03-11

... Loving Support peer counseling services; a treatment group of 900 will be offered Loving Support peer...: Proposed Collection; Comment Request--WIC Breastfeeding Peer Counseling Study AGENCY: Food and Nutrition... for the second phase of the WIC Breastfeeding Peer Counseling Study. The first phase of this study...

HPC Benchmark Suite NMx, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — In the phase II effort, Intelligent Automation Inc., (IAI) and University of Central Florida (UCF) propose to develop a comprehensive numerical test suite for...

Compact, Ultrasensitive Formaldehyde Monitor, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This Small Business Innovative Research Phase I proposal seeks to develop an ultrasensitive, laser-based formaldehyde gas sensor system for airborne and ground-based...

Tactile Data Entry System, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Building on our successful Phase I Tactile Data Entry program, Barron Associates proposes development of a Glove-Enabled Computer Operations (GECO) system to permit...

Architecture-Based Reuse Innovations, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This Phase I proposal responds to the Solicitation requirements by scoping the effort involved in developing a common software executive and aligned library of...

Self-reported previous knee injury and low knee function increase knee injury risk in adolescent female football.

Science.gov (United States)

Clausen, M B; Tang, L; Zebis, M K; Krustrup, P; Hölmich, P; Wedderkopp, N; Andersen, L L; Christensen, K B; Møller, M; Thorborg, K

2016-08-01

Knee injuries are common in adolescent female football. Self-reported previous knee injury and low Knee injury and Osteoarthritis Outcome Score (KOOS) are proposed to predict future knee injuries, but evidence regarding this in adolescent female football is scarce. The aim of this study was to investigate self-reported previous knee injury and low KOOS subscale score as risk factors for future knee injuries in adolescent female football. A sample of 326 adolescent female football players, aged 15-18, without knee injury at baseline, were included. Data on self-reported previous knee injury and KOOS questionnaires were collected at baseline. Time-loss knee injuries and football exposures were reported weekly by answers to standardized text-message questions, followed by injury telephone interviews. A priori, self-reported previous knee injury and low KOOS subscale scores (female football. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Process-based project proposal risk management

Directory of Open Access Journals (Sweden)

Alok Kumar

2016-12-01

Full Text Available We all are aware of the organizational omnipresence. Projects within the organizations are ubiquitous too. Projects achieve their goals successfully if they are planned, scheduled, controlled and implemented well. The project lifecycle of initiating, planning, scheduling, controlling and implementing are very well-planned by project managers and the organizations. Successful projects have well-developed risk management plans to deal with situations impacting projects. Like any other organisation, a university does try to access funds for different purposes too. For such organisations, running a project is not the issue, rather getting a project proposal approved to fund a project is the key. Project proposal processing is done by the nodal office in every organisation. Usually, these nodal offices help in administration and submission of a project proposal for accessing funds. Seldom are these nodal project offices within the organizations facilitate a project proposal approval by proactively reaching out to the project managers. And as project managers prepare project proposals, little or no attention is made to prepare a project proposal risk plan so as to maximise project acquisition. Risk plans are submitted while preparing proposals but these risk plans cater to a requirement to address actual projects upon approval. Hence, a risk management plan for project proposal is either missing or very little effort is made to treat the risks inherent in project acquisition. This paper is an integral attempt to highlight the importance of risk treatment for project proposal stage as an extremely important step to preparing the risk management plan made for projects corresponding to their lifecycle phases. Several tools and techniques have been proposed in the paper to help and guide either the project owner (proposer or the main organisational unit responsible for project management. Development of tools and techniques to further enhance project

Calibrated Phase-Shifting Digital Holographic Microscope Using a Sampling Moiré Technique

Directory of Open Access Journals (Sweden)

Peng Xia

2018-05-01

Full Text Available A calibrated phase-shifting digital holographic microscope system capable of improving the quality of reconstructed images is proposed. Phase-shifting errors are introduced in phase-shifted holograms for numerous reasons, such as the non-linearity of piezoelectric transducers (PZTs, wavelength fluctuations in lasers, and environmental disturbances, leading to poor-quality reconstructions. In our system, in addition to the camera used to record object information, an extra camera is used to record interferograms, which are used to analyze phase-shifting errors using a sampling Moiré technique. The quality of the reconstructed object images can be improved by the phase-shifting error compensation algorithm. Both the numerical simulation and experiment demonstrate the effectiveness of the proposed system.

An introduction to two-phase flows

International Nuclear Information System (INIS)

Lemonnier, Herve

2006-01-01

This course aims at proposing the necessary background for a rational approach to two-phase flows which are notably present in numerous industrial devices and equipment designed to perform energy transfer or mass transfer. The first part proposes a phenomenological approach to main two-phase flow structures and presents their governing variables. The second part presents some proven measurement techniques. The third part focuses on modelling. It recalls the equation elaboration techniques which are based on basic principles of mechanics and thermodynamics and on the application of different averaging operators to these principles. Some useful models are then presented such as models of pressure loss in a duct. The last chapter addresses some fundamental elements of heat transfers in ebullition and condensation

Causes and proposed resolutions of high vibration in NWTF transfer pumps

International Nuclear Information System (INIS)

Trawinski, B.J.

1993-01-01

This Technical Report is intended to communicate the findings from the latest phase of New Waste Transfer Facility (NWTF) transfer pump testing. These tests have identified causes for the high pump vibrations that have been observed during previous phases of transfer pump startup testing, and have led to recommendations for resolving the vibration problem. The paper describes the problem, the test methodology, observations, and recommend actions to correct the vibration problem

Defense Small Business Innovation Research Program (SBIR). Abstracts of Phase 2 Awards, 1984.

Science.gov (United States)

165 proposals for funding in Phase II of the Small Business Innovation Research (SBIR) Program. These proposals were selected from those submitted by... small research and development firms awarded Phase I contracts from the FY 1984 solicitation. In order to make information available on the technical

Adaptive DSPI phase denoising using mutual information and 2D variational mode decomposition

Science.gov (United States)

Xiao, Qiyang; Li, Jian; Wu, Sijin; Li, Weixian; Yang, Lianxiang; Dong, Mingli; Zeng, Zhoumo

2018-04-01

In digital speckle pattern interferometry (DSPI), noise interference leads to a low peak signal-to-noise ratio (PSNR) and measurement errors in the phase map. This paper proposes an adaptive DSPI phase denoising method based on two-dimensional variational mode decomposition (2D-VMD) and mutual information. Firstly, the DSPI phase map is subjected to 2D-VMD in order to obtain a series of band-limited intrinsic mode functions (BLIMFs). Then, on the basis of characteristics of the BLIMFs and in combination with mutual information, a self-adaptive denoising method is proposed to obtain noise-free components containing the primary phase information. The noise-free components are reconstructed to obtain the denoising DSPI phase map. Simulation and experimental results show that the proposed method can effectively reduce noise interference, giving a PSNR that is higher than that of two-dimensional empirical mode decomposition methods.

Phase retrieval from reflective fringe patterns of double-sided transparent objects

International Nuclear Information System (INIS)

Huang, Lei; Asundi, Anand Krishna

2012-01-01

‘Ghosted’ fringe patterns simultaneously reflected from both the upper and lower sides of a transparent target in the fringe reflection technique are captured for transparent surface 3D shape measurement, but the phase retrieval from the captured ‘ghosted’ fringe patterns is still not solved. A novel method is proposed to solve this issue by using two sets of phase-shifted fringe patterns with slightly different frequencies. The nonlinear least-squares method is used to estimate the fringe phase and modulation from both front and rear interfaces. Several simulations are done to show the feasibility of the proposed method. The influence of fringe noise on the algorithm is studied as well, which indicates that the proposed method is able to retrieve the phase from double-sided reflective fringe patterns with fringe noise equivalent to that in practical measurements. The merits and limitations of the method are discussed and recommendations for future studies are made. (paper)

Quantum rewinding via phase estimation

Science.gov (United States)

Tabia, Gelo Noel

2015-03-01

In cryptography, the notion of a zero-knowledge proof was introduced by Goldwasser, Micali, and Rackoff. An interactive proof system is said to be zero-knowledge if any verifier interacting with an honest prover learns nothing beyond the validity of the statement being proven. With recent advances in quantum information technologies, it has become interesting to ask if classical zero-knowledge proof systems remain secure against adversaries with quantum computers. The standard approach to show the zero-knowledge property involves constructing a simulator for a malicious verifier that can be rewinded to a previous step when the simulation fails. In the quantum setting, the simulator can be described by a quantum circuit that takes an arbitrary quantum state as auxiliary input but rewinding becomes a nontrivial issue. Watrous proposed a quantum rewinding technique in the case where the simulation's success probability is independent of the auxiliary input. Here I present a more general quantum rewinding scheme that employs the quantum phase estimation algorithm. This work was funded by institutional research grant IUT2-1 from the Estonian Research Council and by the European Union through the European Regional Development Fund.

Crew Cerebral Oxygen Monitor, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This Phase I SBIR proposal is aimed at developing a non-invasive, optical method for monitoring the state of consciousness of crew members in operational...

Crew Cerebral Oxygen Monitor, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — This Phase II SBIR proposal is aimed at developing a non-invasive, optical method for monitoring crew member state of awareness in operational environments. All...

Mutual phase-locking of several spin-torque nano-oscillators

International Nuclear Information System (INIS)

Prokopenko, O.V.; Sulimenko, O.R.

2011-01-01

Criterions for evaluating the effectiveness of mutual phase-locking of several spin-torque nano-oscillators (STNO) are proposed. An application of one of the criterions to describe the process of mutual phase-locking of the three almost identical STNO's is considered

Unconventional phase transitions in liquid crystals

Science.gov (United States)

Kats, E. I.

2017-12-01

According to classical textbooks on thermodynamics or statistical physics, there are only two types of phase transitions: continuous, or second-order, in which the latent heat L is zero, and first-order, in which L ≠ 0. Present-day textbooks and monographs also mention another, stand-alone type—the Berezinskii-Kosterlitz-Thouless transition, which exists only in two dimensions and shares some features with first- and second-order phase transitions. We discuss examples of non-conventional thermodynamic behavior (i.e., which is inconsistent with the theoretical phase transition paradigm now universally accepted). For phase transitions in smectic liquid crystals, mechanisms for nonconventional behavior are proposed and the predictions they imply are examined.

Enhanced mixing in two-phase Taylor-Couette flows

International Nuclear Information System (INIS)

Dherbecourt, Diane

2015-01-01

In the scope of the nuclear fuel reprocessing, Taylor-Couette flows between two concentric cylinders (the inner one in rotation and the outer one at rest) are used at laboratory scale to study the performances of new liquid/liquid extraction processes. Separation performances are strongly related to the mixing efficiency, the quantification of the latter is therefore of prime importance. A previous Ph.D. work has related the mixing properties to the hydrodynamics parameters in single-phase flow, using both experimental and numerical investigations. The Reynolds number, flow state and vortices height (axial wavelength) impacts were thus highlighted. This Ph.D. work extends the previous study to two-phase configurations. For experimental simplification, and to avoid droplets coalescence or breakage, spherical solid particles of PMMA from 800 μm to 1500 μm diameter are used to model rigid droplets. These beads are suspended in an aqueous solution of dimethyl sulfoxide (DMSO) and potassium Thiocyanate (KSCN). The experimental setup uses coupled Particle Image Velocimetry (PIV) and Planar Laser-Induced Fluorescence (PLIF) to access simultaneously the hydrodynamic and the mixing properties. Although the two phases are carefully chosen to match in density and refractive index, these precautions are not sufficient to ensure a good measurement quality, and a second PLIF channel is added to increase the precision of the mixing quantification. The classical PLIF channel monitors the evolution of Rhodamine WT concentration, while the additional PLIF channel is used to map a Fluorescein dye, which is homogeneously concentrated inside the gap. This way, a dynamic mask of the bead positions can be created and used to correct the Rhodamine WT raw images. Thanks to this experimental setup, a parametric study of the particles size and concentration is achieved. A double effect of the dispersed phase is evidenced. On one hand, the particles affect the flow hydrodynamic properties

SAR Interferogram Filtering of Shearlet Domain Based on Interferometric Phase Statistics

Directory of Open Access Journals (Sweden)

Yonghong He

2017-02-01

Full Text Available This paper presents a new filtering approach for Synthetic Aperture Radar (SAR interferometric phase noise reduction in the shearlet domain, depending on the coherent statistical characteristics. Shearlets provide a multidirectional and multiscale decomposition that have advantages over wavelet filtering methods when dealing with noisy phase fringes. Phase noise in SAR interferograms is directly related to the interferometric coherence and the look number of the interferogram. Therefore, an optimal interferogram filter should incorporate information from both of them. The proposed method combines the phase noise standard deviation with the shearlet transform. Experimental results show that the proposed method can reduce the interferogram noise while maintaining the spatial resolution, especially in areas with low coherence.

Electrical transport and phase stability in silver iodide-cadmium iodide

Energy Technology Data Exchange (ETDEWEB)

Brightwell, J.W.; Buckley, C.N.; Miller, L.S.; Ray, B. (Lanchester Polytechnic, Coventry (UK))

1983-03-16

A form of the equilibrium diagram for the system AgI-CdI/sub 2/ is proposed on the basis of thermal, X-ray diffractometer, and electrical conductivity data. Only one intermediate equilibrium phase, of composition Ag/sub 2/CdI/sub 4/, of tetragonal form with a/sub 0/ = 6.35 A and c/sub 0/ = 12.7 A is apparent; the previously reported hexagonal form of this composition being metastable. Low levels of CdI/sub 2/ are found to enhance the formation of the cubic, ..gamma..-form, af AgI and to increase the electrical conductivity. For various levels of CdI/sub 2/ inclusion in AgI, the principal increase in conductivity occurs in the region of 110 /sup 0/C instead of at 146 /sup 0/C as in pure AgI.

640 Gbit/s RZ-to-NRZ format conversion based on optical phase filtering

DEFF Research Database (Denmark)

Maram, Reza; Kong, Deming; Galili, Michael

2014-01-01

We propose a novel approach for all optical RZ-to-NRZ conversion based on optical phase filtering. The proposed concept is experimentally validated through format conversion of a 640 Gbit/s coherent RZ signal to NRZ signal using a simple phase filter implemented by a commercial optical waveshaper....

Kinematic approach to off-diagonal geometric phases of nondegenerate and degenerate mixed states

International Nuclear Information System (INIS)

Tong, D.M.; Oh, C.H.; Sjoeqvist, Erik; Filipp, Stefan; Kwek, L.C.

2005-01-01

Off-diagonal geometric phases have been developed in order to provide information of the geometry of paths that connect noninterfering quantal states. We propose a kinematic approach to off-diagonal geometric phases for pure and mixed states. We further extend the mixed-state concept proposed in [Phys. Rev. Lett. 90, 050403 (2003)] to degenerate density operators. The first- and second-order off-diagonal geometric phases are analyzed for unitarily evolving pairs of pseudopure states

Research proposal on : amplitude modulated reflectometry system for JET divertor

International Nuclear Information System (INIS)

Sanchez, J.; Branas, T.; Estrada, T.; Luna, E. de la.

1992-01-01

Amplitude Modulated reflectometry is presented here as a tool for density profile measurements in the JET divertor plasmas. One of the main problems which has been presented in most reflectometers during the last years is the need for a coherent tracking of the phase delay: fast density fluctuations and strong modulation on the amplitude of the reflected signal usually bring to fringe jumps' in the phase signal, which are a big problem when the phase values are much larger than 2 pi. The conditions in the JET divertor plasmas: plasma geometry, access and long oversized broad-band waveguide paths makes very difficult the phase measurements at the millimeter wave range. AM reflectometry is to some extension an intermediate solution between the classical phase delay reflectometry, so far applied to small distances, and the time domain reflectometry, used for ionospheric studies and recently also proposed for fusion plasma. the main advantage is to allow the use of millimeter wave reflectometry with moderate phase shifts (approx 2 pi). (author)

Vapor Chamber with Phase Change Material-based Wick Structure for Thermal Control of Manned Spacecraft, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — In response to NASA SBIR solicitation H3.01 "Thermal Control for Future Human Exploration", Advanced Cooling Technologies, Inc. (ACT) is proposing a novel Phase...

Phase diagram of classical electronic bilayers

International Nuclear Information System (INIS)

Ranganathan, S; Johnson, R E

2006-01-01

Extensive molecular dynamics calculations have been performed on classical, symmetric electronic bilayers at various values of the coupling strength Γ and interlayer separation d to delineate its phase diagram in the Γ-d plane. We studied the diffusion, the amplitude of the main peak of the intralayer static structure factor and the peak positions of the intralayer pair correlation function with the aim of defining equivalent signatures of freezing and constructing the resulting phase diagram. It is found that for Γ greater than 75, crystalline structures exist for a certain range of interlayer separations, while liquid phases are favoured at smaller and larger d. It is seen that there is good agreement between our phase diagram and previously published ones

Phase diagram of classical electronic bilayers

Energy Technology Data Exchange (ETDEWEB)

Ranganathan, S [Department of Physics, Royal Military College of Canada, Kingston, Ontario K7K 7B4 (Canada); Johnson, R E [Department of Mathematics and Computer Science, Royal Military College of Canada, Kingston, Ontario K7K 7B4 (Canada)

2006-04-28

Extensive molecular dynamics calculations have been performed on classical, symmetric electronic bilayers at various values of the coupling strength {gamma} and interlayer separation d to delineate its phase diagram in the {gamma}-d plane. We studied the diffusion, the amplitude of the main peak of the intralayer static structure factor and the peak positions of the intralayer pair correlation function with the aim of defining equivalent signatures of freezing and constructing the resulting phase diagram. It is found that for {gamma} greater than 75, crystalline structures exist for a certain range of interlayer separations, while liquid phases are favoured at smaller and larger d. It is seen that there is good agreement between our phase diagram and previously published ones.

Underestimation of Severity of Previous Whiplash Injuries

Science.gov (United States)

Naqui, SZH; Lovell, SJ; Lovell, ME

2008-01-01

INTRODUCTION We noted a report that more significant symptoms may be expressed after second whiplash injuries by a suggested cumulative effect, including degeneration. We wondered if patients were underestimating the severity of their earlier injury. PATIENTS AND METHODS We studied recent medicolegal reports, to assess subjects with a second whiplash injury. They had been asked whether their earlier injury was worse, the same or lesser in severity. RESULTS From the study cohort, 101 patients (87%) felt that they had fully recovered from their first injury and 15 (13%) had not. Seventy-six subjects considered their first injury of lesser severity, 24 worse and 16 the same. Of the 24 that felt the violence of their first accident was worse, only 8 had worse symptoms, and 16 felt their symptoms were mainly the same or less than their symptoms from their second injury. Statistical analysis of the data revealed that the proportion of those claiming a difference who said the previous injury was lesser was 76% (95% CI 66–84%). The observed proportion with a lesser injury was considerably higher than the 50% anticipated. CONCLUSIONS We feel that subjects may underestimate the severity of an earlier injury and associated symptoms. Reasons for this may include secondary gain rather than any proposed cumulative effect. PMID:18201501

One-phase and two-phase homologous curves for coolant pumps of the pressurized light water nuclear reactors

International Nuclear Information System (INIS)

Santos, G.A. dos.

1990-01-01

The two-phase coolant pump model of pressurized light water nuclear reactors is an important point for the loss of primary coolant accident analysis. The single-phase pump characteristics are an essential feature for operational transients studies, for example, the shut-down and start-up of pump. These parameters, in terms of the homologous curves, set up the complete performance of the pump and are input for transients and accidents analysis thermal-hydraulic codes. This work propose a mathematical model able to predict the single-phase and two-phase homologous curves where it was incorporated geometric and operational pump condition. The results were compared with the experimental tests data from literature and it has showed a good agreement. (author)

Abstracts of Phase 1 awards, [fiscal year] 1987

International Nuclear Information System (INIS)

1987-01-01

Contained in this booklet are abstracts of the Phase I awards made in Fiscal Year 1987 under the Small Business Innovation Research (SBIR) program in the Department of Energy (DOE). The program is designed for implementation in a three-phase process, with Phase I determining the scientific or technical merit and feasibility of ideas proposed for investigation. The period of performance in this initial phase is relatively brief, typically about 6 months, and the awards are limited to $50,000. Phase II is the principal research or research and development effort, and the awards are as high as $500,000 for work to be performed in periods of up to 2 years. Phase III is the commercial application. The 111 Phase I projects described were selected in a highly competitive process from a total of 942 proposals received in response to the 1987 Solicitation. They cover the fields of chemistry, materials, control systems, plant natural products, instrumentation, nuclear medicine, health and environmental effects, high energy physics, particle accelerators, nuclear physics, plasma diagnostics and confinement, fusion energy systems, robotics and remote systems, nuclear reactors, space nuclear power, fuel cycle, decontamination/decommissioning, commputers in nuclear plants, coal, enhanced oil recovery/tar sands, fossil energy, photovoltaics, solar thermal, ceramics for heat engines, and industrial separation, conversion and recovery processes

Compact 2-Micron Transmitter for Remote Sensing Applications, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — In this Phase II effort we propose to work with NASA to extend the Phase I achievements, which focused on design and development of very compact master and...

Group theoretical arguments on the Landau theory of second-order phase transitions applied to the phase transitions in some liquid crystals

International Nuclear Information System (INIS)

Rosciszewski, K.

1979-01-01

The phase transitions between liquids and several of the simplest liquid crystalline phases (nematic, cholesteric, and the simplest types of smectic A and smectic C) were studied from the point of view of the group-theoretical arguments of Landau theory. It was shown that the only possible candidates for second-order phase transitions are those between nematic and smectic A, between centrosymmetric nematic and smectic C and between centrosymmetric smectic A and smectic C. Simple types of density functions for liquid crystalline phases are proposed. (author)

Cryptographic analysis on the key space of optical phase encryption algorithm based on the design of discrete random phase mask

Science.gov (United States)

Lin, Chao; Shen, Xueju; Li, Zengyan

2013-07-01

The key space of phase encryption algorithm using discrete random phase mask is investigated by numerical simulation in this paper. Random phase mask with finite and discrete phase levels is considered as the core component in most practical optical encryption architectures. The key space analysis is based on the design criteria of discrete random phase mask. The role of random amplitude mask and random phase mask in optical encryption system is identified from the perspective of confusion and diffusion. The properties of discrete random phase mask in a practical double random phase encoding scheme working in both amplitude encoding (AE) and phase encoding (PE) modes are comparably analyzed. The key space of random phase encryption algorithm is evaluated considering both the encryption quality and the brute-force attack resistibility. A method for enlarging the key space of phase encryption algorithm is also proposed to enhance the security of optical phase encryption techniques.

Mass transfer in liquid phase catalytic exchange column of trickle bed type

International Nuclear Information System (INIS)

Yamanishi, Toshihiko; Iwai, Yasunori; Okuno, Kenji

1995-09-01

The mechanism of mass transfer in a liquid phase catalytic exchange column was discussed for a trickle bed type. A new model has been proposed on the basis of this mass transfer mechanism; and several problems for the previous reported models were pointed out in the derivation of the model. An overall rate equation was first derived from the vapor-hydrogen exchange in the model. The mass transfer for the vapor-hydrogen exchange was decomposed to the following three steps: the mass transfer in a gas boundary layer on a catalyst particle; the mass transfer within the pores in the catalyst; and the chemical reaction on the surface of the catalyst. The water-vapor scrubbing process was considered as a series of the mass transfers in gas and liquid boundary layers on the wetted surfaces of the catalyst and packings or wall of the column. Significant subjects to be studied were proposed from the viewpoint of the validity of the model and the optimization of the column. (author)

The biomechanics of running in athletes with previous hamstring injury: A case-control study.

Science.gov (United States)

Daly, C; Persson, U McCarthy; Twycross-Lewis, R; Woledge, R C; Morrissey, D

2016-04-01

Hamstring injury is prevalent with persistently high reinjury rates. We aim to inform hamstring rehabilitation by exploring the electromyographic and kinematic characteristics of running in athletes with previous hamstring injury. Nine elite male Gaelic games athletes who had returned to sport after hamstring injury and eight closely matched controls sprinted while lower limb kinematics and muscle activity of the previously injured biceps femoris, bilateral gluteus maximus, lumbar erector spinae, rectus femoris, and external oblique were recorded. Intergroup comparisons of muscle activation ratios and kinematics were performed. Previously injured athletes demonstrated significantly reduced biceps femoris muscle activation ratios with respect to ipsilateral gluteus maximus (maximum difference -12.5%, P = 0.03), ipsilateral erector spinae (maximum difference -12.5%, P = 0.01), ipsilateral external oblique (maximum difference -23%, P = 0.01), and contralateral rectus femoris (maximum difference -22%, P = 0.02) in the late swing phase. We also detected sagittal asymmetry in hip flexion (maximum 8°, P = 0.01), pelvic tilt (maximum 4°, P = 0.02), and medial rotation of the knee (maximum 6°, P = 0.03) effectively putting the hamstrings in a lengthened position just before heel strike. Previous hamstring injury is associated with altered biceps femoris associated muscle activity and potentially injurious kinematics. These deficits should be considered and addressed during rehabilitation. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Improved thermal lattice Boltzmann model for simulation of liquid-vapor phase change

Science.gov (United States)

Li, Qing; Zhou, P.; Yan, H. J.

2017-12-01

In this paper, an improved thermal lattice Boltzmann (LB) model is proposed for simulating liquid-vapor phase change, which is aimed at improving an existing thermal LB model for liquid-vapor phase change [S. Gong and P. Cheng, Int. J. Heat Mass Transfer 55, 4923 (2012), 10.1016/j.ijheatmasstransfer.2012.04.037]. First, we emphasize that the replacement of ∇ .(λ ∇ T ) /∇.(λ ∇ T ) ρ cV ρ cV with ∇ .(χ ∇ T ) is an inappropriate treatment for diffuse interface modeling of liquid-vapor phase change. Furthermore, the error terms ∂t 0(T v ) +∇ .(T vv ) , which exist in the macroscopic temperature equation recovered from the previous model, are eliminated in the present model through a way that is consistent with the philosophy of the LB method. Moreover, the discrete effect of the source term is also eliminated in the present model. Numerical simulations are performed for droplet evaporation and bubble nucleation to validate the capability of the model for simulating liquid-vapor phase change. It is shown that the numerical results of the improved model agree well with those of a finite-difference scheme. Meanwhile, it is found that the replacement of ∇ .(λ ∇ T ) /∇ .(λ ∇ T ) ρ cV ρ cV with ∇ .(χ ∇ T ) leads to significant numerical errors and the error terms in the recovered macroscopic temperature equation also result in considerable errors.