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Sample records for preheating phase narrow

  1. Nonlinear ultrasonic phased array imaging of closed cracks using global preheating and local cooling

    Science.gov (United States)

    Ohara, Yoshikazu; Takahashi, Koji; Ino, Yoshihiro; Yamanaka, Kazushi

    2015-10-01

    Closed cracks are the main cause of underestimation in ultrasonic inspection, because the ultrasound transmits through the crack. Specifically, the measurement of closed-crack depth in coarse-grained materials, which are highly attenuative due to linear scatterings at the grains, is the most difficult issue. To solve this problem, we have developed a temporary crack opening method, global preheating and local cooling (GPLC), using tensile thermal stress, and a high-selectivity imaging method, load difference phased array (LDPA), based on the subtraction of phased array images between different stresses. To demonstrate our developed method, we formed a closed fatigue crack in coarse-grained stainless steel (SUS316L) specimen. As a result of applying it to the specimen, the high-selectivity imaging performance was successfully demonstrated. This will be useful in improving the measurement accuracy of closed-crack depths in coarse-grained material.

  2. Restoring the sting to metric preheating

    CERN Document Server

    Bassett, B A; Maartens, R; Kaiser, D I; Bassett, Bruce A.; Gordon, Chris; Maartens, Roy; Kaiser, David I.

    2000-01-01

    The relative growth of field and metric perturbations during preheating is sensitive to initial conditions set in the preceding inflationary phase. Recent work suggests this may protect super-Hubble metric perturbations from resonant amplification during preheating. We show that this possibility is fragile and extremely sensitive to the specific form of the interactions between the inflaton and other fields. The suppression is naturally absent in two classes of preheating in which either (1) the critical points (hence the vacua) of the effective potential during inflation are deformed away from the origin, or (2) the effective masses of fields during inflation are small but during preheating are large. Unlike the simple toy model of a g^2 \\phi^2 \\chi^2 coupling, most realistic particle physics models contain these other features. Moreover, they generically lead to both adiabatic and isocurvature modes and non-Gaussian scars on super-Hubble scales. Large-scale coherent magnetic fields may also appear naturally...

  3. Enhanced preheating after multi-field inflation: on the importance of being special

    Energy Technology Data Exchange (ETDEWEB)

    Battefeld, Thorsten; Eggemeier, Alexander [Institute for Astrophysics, University of Goettingen, Friedrich Hund Platz 1, D-37077 Goettingen (Germany); Giblin, John T. Jr., E-mail: tbattefe@astro.physik.uni-goettingen.de, E-mail: a.eggemeier@stud.uni-goettingen.de, E-mail: giblinj@kenyon.edu [Department of Physics, Kenyon College, Gambier, OH 43022 (United States)

    2012-11-01

    We discuss preheating after multi-field inflation in the presence of several preheat matter fields that become light in the vicinity of (but not at) the inflatons' VEV, at distinct extra-species-points (ESP); this setup is motivated by inflationary models that include particle production during inflation, e.g. trapped inflation, grazing ESP encounters or modulated trapping, among others. While de-phasing of inflatons tends to suppress parametric resonance, we find two new effects leading to efficient preheating: particle production during the first in-fall (efficient if many preheat matter fields are present) and a subsequent (narrow) resonance phase (efficient if an ESP happens to be at one of several distinct distances from the inflatons' VEV). Particles produced during the first in-fall are comprised of many species with low occupation number, while the latter are made up of a few species with high occupation number. We provide analytic descriptions of both phases in the absence of back-reaction, which we test numerically. We further perform lattice simulations to investigate the effects of back-reaction. We find resonances to be robust and the most likely cause of inflaton decay in multi-field trapped inflation if ESP distributions are dense.

  4. Preheating in New Inflation

    CERN Document Server

    Desroche, M; Kratochvil, J; Linde, Andrei D; Desroche, Mariel; Felder, Gary N.; Kratochvil, Jan M.; Linde, Andrei

    2005-01-01

    During the last ten years a detailed investigation of preheating was performed for chaotic inflation and for hybrid inflation. However, nonperturbative effects during reheating in the new inflation scenario remained practically unexplored. We do a full analysis of preheating in new inflation, using a combination of analytical and numerical methods. We find that the decay of the homogeneous component of the inflaton field and the resulting process of spontaneous symmetry breaking in the simplest models of new inflation usually occurs almost instantly: for the new inflation on the GUT scale it takes only about 5 oscillations of the field distribution. The decay of the homogeneous inflaton field is so efficient because of a combined effect of tachyonic preheating and parametric resonance. At that stage, the homogeneous oscillating inflaton field decays into a collection of waves of the inflaton field, with a typical wavelength of the order of the inverse inflaton mass. This stage usually is followed by a long st...

  5. Preheating after modular inflation

    Science.gov (United States)

    Barnaby, Neil; Bond, J. Richard; Huang, Zhiqi; Kofman, Lev

    2009-12-01

    We study (p)reheating in modular (closed string) inflationary scenarios, with a special emphasis on Kähler moduli/Roulette models. It is usually assumed that reheating in such models occurs through perturbative decays. However, we find that there are very strong non-perturbative preheating decay channels related to the particular shape of the inflaton potential (which is highly nonlinear and has a very steep minimum). Preheating after modular inflation, proceeding through a combination of tachyonic instability and broad-band parametric resonance, is perhaps the most violent example of preheating after inflation known in the literature. Further, we consider the subsequent transfer of energy to the standard model sector in scenarios where the standard model particles are confined to a D7-brane wrapping the inflationary blow-up cycle of the compactification manifold or, more interestingly, a non-inflationary blow-up cycle. We explicitly identify the decay channels of the inflaton in these two scenarios. We also consider the case where the inflationary cycle shrinks to the string scale at the end of inflation; here a field theoretical treatment of reheating is insufficient and one must turn instead to a stringy description. We estimate the decay rate of the inflaton and the reheat temperature for various scenarios.

  6. Preheating with fractional powers

    Science.gov (United States)

    Moghaddam, Hossein Bazrafshan; Brandenberger, Robert

    2016-11-01

    We consider preheating in models in which the potential for the inflaton is given by a fractional power, as is the case in axion monodromy inflation. We assume a standard coupling between the inflaton field and a scalar matter field. We find that in spite of the fact that the oscillation of the inflaton about the field value which minimizes the potential is anharmonic, there is nevertheless a parametric resonance instability, and we determine the Floquet exponent which describes this instability as a function of the parameters of the inflaton potential.

  7. Differential-phase-shift quantum key distribution using heralded narrow-band single photons.

    Science.gov (United States)

    Liu, Chang; Zhang, Shanchao; Zhao, Luwei; Chen, Peng; Fung, C-H F; Chau, H F; Loy, M M T; Du, Shengwang

    2013-04-22

    We demonstrate the first proof of principle differential phase shift (DPS) quantum key distribution (QKD) using narrow-band heralded single photons with amplitude-phase modulations. In the 3-pulse case, we obtain a quantum bit error rate (QBER) as low as 3.06% which meets the unconditional security requirement. As we increase the pulse number up to 15, the key creation efficiency approaches 93.4%, but with a cost of increasing the QBER. Our result suggests that narrow-band single photons maybe a promising source for the DPS-QKD protocol.

  8. Numerical investigation of the mechanism of two-phase flow instability in parallel narrow channels

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Lian [Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University (China); Chen, Deqi, E-mail: chendeqi@cqu.edu.cn [Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University (China); CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology, Nuclear Power Institute of China, Chengdu 610041 (China); Huang, Yanping, E-mail: hyanping007@163.com [CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology, Nuclear Power Institute of China, Chengdu 610041 (China); Yuan, Dewen; Wang, Yanling [CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology, Nuclear Power Institute of China, Chengdu 610041 (China); Pan, Liangming [Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Chongqing University (China)

    2015-06-15

    Highlights: • A mathematical model is proposed to predict the two-phase flow instability. • The mathematical model predicted result agrees well with the experimental result. • Oscillation characteristics of the two-phase flow instability is discussed in detail. - Abstract: In this paper, the mechanism of two-phase flow instability in parallel narrow channels is studied theoretically, and the characteristic of the flow instability is discussed in detail. Due to the significant confining effect of the narrow channel on the vapor–liquid interface, the two-phase flow resistance in the narrow channel is probably different from that in conventional channel. Therefore, the vapor confined number (N{sub conf}), defined by the size of narrow channel and bubble detachment diameter, is considered in the “Chisholm B model” to investigate the two-phase flow pressure drop. The flow instability boundaries are plotted in parameter plane with phase-change-number (N{sub pch}) and subcooling-number (N{sub sub}) under different working conditions. It is found that the predicted result agrees well with the experimental result. According to the predicted result, the oscillation behaviors near the flow instability boundary indicate that the Supercritical Hopf bifurcation appears in high sub-cooled region and the Subcritical Hopf bifurcation appears in low sub-cooled region. Also, a detailed analysis about the effects of key parameters on the characteristic of two-phase flow instability and the flow instability boundary is proposed, including the effects of inlet subcooling, heating power, void distribution parameter and drift velocity.

  9. Preheating after N-flation

    CERN Document Server

    Battefeld, Diana

    2008-01-01

    We study preheating in N-flation, assuming the Mar\\v{c}enko-Pastur mass distribution, equal energy initial conditions at the beginning of inflation and equal axion-matter couplings, where matter is taken to be a single, massless bosonic field. By numerical analysis we find that preheating via parametric resonance is suppressed, indicating that the old theory of perturbative preheating is applicable. While the tensor-to-scalar ratio, the non-Gaussianity parameters and the scalar spectral index computed for N-flation are similar to those in single field inflation (at least within an observationally viable parameter region), our results suggest that the physics of preheating can differ significantly from the single field case.

  10. Investigation of optimal fluoroglass preheat

    CERN Document Server

    Baba, S; Toyoda, T; Wakamatsu, O; Machida, T

    2002-01-01

    The regular preheat condition of fluoroglass GD-301 (Chiyoda Technol Co., its size is 1.5 mm phi x 8.5 mm.) is temperature 70 deg C and time 30 minutes. When we measured dose 5.00 Gy at high energy X-ray processed with this condition, we observed build-up phenomenon according to elapsed days. So we investigated the optimal preheat temperature and time by measuring fluoroglass doses daily for several days. Fluoroglasses were irradiated 2.00 Gy of 10 MV X-ray at the reference depth using MEVATRON KD 2/50 PRIMUS (Toshiba Co.). First, we measured doses during 17 days after preheating them for 30 minutes, changing preheat temperatures from 50 deg C to 350 deg C at some intervals. Second, we measured doses during 9 days after preheating them at 70 deg C and at temperatures representing the maximum value and the most frequent value, changing preheat time from 5 minutes to 2 hours at some intervals. Doses increased up to around 115 deg C and decreased after that, and it seemed as if glasses were annealed at 350 deg C...

  11. Violent Preheating in Inflation with Nonminimal Coupling

    CERN Document Server

    Ema, Yohei; Mukaida, Kyohei; Nakayama, Kazunori

    2016-01-01

    We study particle production at the preheating era in inflation models with nonminimal coupling $\\xi \\phi^2R$ and quartic potential $\\lambda \\phi^4/4$ for several cases: real scalar inflaton, complex scalar inflaton and Abelian Higgs inflaton. We point out that the preheating proceeds much more violently than previously thought. If the inflaton is a complex scalar, the phase degree of freedom is violently produced at the first stage of preheating. If the inflaton is a Higgs field, the longitudinal gauge boson production is similarly violent. This is caused by a spike-like feature in the time dependence of the inflaton field, which may be understood as a consequence of short time scale during which the effective potential or kinetic term changes suddenly. The produced particles typically have very high momenta $k \\lesssim \\sqrt{\\lambda}M_\\text{P}$. The production might be so strong that almost all the energy of the inflaton is carried away within one oscillation for $\\xi^2\\lambda \\gtrsim 1$. This may significa...

  12. Two-phase flow and boiling heat transfer in two vertical narrow annuli

    Energy Technology Data Exchange (ETDEWEB)

    Peng Changhong [Department of Nuclear and Thermal Power Engineering, Xi' an Jiaotong University, Xian 710049 (China)]. E-mail: pxm321@163.com; Guo Yun [Department of Nuclear and Thermal Power Engineering, Xi' an Jiaotong University, Xian 710049 (China); Qiu Suizheng [Department of Nuclear and Thermal Power Engineering, Xi' an Jiaotong University, Xian 710049 (China); Jia Dounan [Department of Nuclear and Thermal Power Engineering, Xi' an Jiaotong University, Xian 710049 (China); Nie Changhua [Nuclear Power Institute of China, Chengdu 610041 (China)

    2005-07-01

    Experimental study associated with two-phase flow and heat transfer during flow boiling in two vertical narrow annuli has been conducted. The parameters examined were: mass flux from 38.8 to 163.1 kg/m{sup 2} s; heat flux from 4.9 to 50.7 kW/m{sup 2} for inside tube and from 4.2 to 78.8 kW/m{sup 2} for outside tube; equilibrium mass quality from 0.02 to 0.88; system pressure from 1.5 to 6.0 MPa. It was found that the boiling heat transfer was strongly influenced by heat flux, while the effect of mass velocity and mass quality were not very significant. This suggested that the boiling heat transfer was mainly via nucleate boiling. The data were used to develop a new correlation for boiling heat transfer in the narrow annuli. In the two-phase flow study, the comparison with the correlation of Chisholm [Chisholm, D., 1967. A theoretical basis for the Lockhart-Martinelli correlation for two-phase flow. Int. J. Heat Mass Transfer 10, 1767-1778] and Mishima and Hibiki [Mishima, K., Hibiki, T., 1996. Some characteristics of air-water two-phase flow in small diameter vertical tubes. Int. J. Multiphase Flow 22, 703-712] indicated that the existing correlations could not predict the two-phase multiplier in the narrow annuli well. Based on the experimental data, a new correlation was developed.

  13. Gravitational-wave mediated preheating

    Directory of Open Access Journals (Sweden)

    Stephon Alexander

    2015-04-01

    Full Text Available We propose a new preheating mechanism through the coupling of the gravitational field to both the inflaton and matter fields, without direct inflaton–matter couplings. The inflaton transfers power to the matter fields through interactions with gravitational waves, which are exponentially enhanced due to an inflation–graviton coupling. One such coupling is the product of the inflaton to the Pontryagin density, as in dynamical Chern–Simons gravity. The energy scales involved are constrained by requiring that preheating happens fast during matter domination.

  14. Aspects of wave turbulence in preheating

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Henrique P. de; Crespo, Jose A. de A. [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    Full text: In the simplest chaotic inflationary model, the Universe has an exponentially fast expansion phase driven by a single scalar field. After inflation, the preheating phase takes place. This phase is characterized when the inflaton performs coherent oscillations about its minimum value and is followed by a huge production of particles. In other terms, there is an energy transfer to small inhomogeneous fluctuations of the inflaton field. The long term behavior ends up in a thermalized universe. In this paper, we have studied numerically the late stages of preheating in a model with a quartic potential V (ϕ) = ¼λ ϕ{sup 4}. We have considered the universe as a squared box with periodic boundary conditions, and applied the collocation method to integrate the field equations. We have shown that the dynamics of the inflaton together with its initially small fluctuations is extremely rich. In the first stage, the parametric resonance is responsible for the exponential growth of some modes. In the sequence, the back reaction of these resonant modes triggers the transfer of energy to other modes or fluctuations. Subsequently, the transfer of energy from the inflaton to thermalize the universe is typical of a turbulent system. In the last part, we have considered the back reaction of the inflaton field in the expansion of the universe. (author)

  15. Phase-referenced Interferometry and Narrow-angle Astrometry with SUSI

    CERN Document Server

    Kok, Y; Tuthill, P G; Robertson, J G; Warrington, B A; Rizzuto, A C; Tango, W J

    2013-01-01

    The Sydney University Stellar Interferometer (SUSI) now incorporates a new beam combiner, called the Microarcsecond University of Sydney Companion Astrometry instrument (MUSCA), for the purpose of high precision differential astrometry of bright binary stars. Operating in the visible wavelength regime where photon-counting and post-processing fringe tracking is possible, MUSCA will be used in tandem with SUSI's primary beam combiner, Precision Astronomical Visible Observations (PAVO), to record high spatial resolution fringes and thereby measure the separation of fringe packets of binary stars. In its current phase of development, the dual beam combiner configuration has successfully demonstrated for the first time a dual-star phase-referencing operation in visible wavelengths. This paper describes the beam combiner optics and hardware, the network of metrology systems employed to measure every non-common path between the two beam combiners and also reports on a recent narrow-angle astrometric observation of ...

  16. Formation of sub-horizon black holes from preheating

    CERN Document Server

    Torres-Lomas, E; Malik, Karim A; Ureña-López, L Arturo

    2014-01-01

    We study the production of primordial black holes (PBHs) during the preheating stage that follows a chaotic inflationary phase. The scalar fields present in the process are evolved numerically using a modified version of the HLATTICE code. From the output of the numerical simulation we compute the probability distribution of curvature fluctuations paying particular attention to sub-horizon scales. We find that in some specific models these modes grow to large amplitudes developing highly non-Gaussian probability distributions. We then calculate PBH abundances using the standard Press-Schechter criterion and find that overproduction of PBHs is likely in some regions of the chaotic preheating parameter-space.

  17. Nonlinear Inflaton Fragmentation after Preheating

    CERN Document Server

    Felder, G N; Felder, Gary N.; Kofman, Lev

    2007-01-01

    We consider the nonlinear dynamics of inflaton fragmentation during and after preheating in the simplest model of chaotic inflation. While the earlier regime of parametric resonant particle production and the later turbulent regime of interacting fields evolving towards equilibrium are well identified and understood, the short intermediate stage of violent nonlinear dynamics remains less explored. Lattice simulations of fully nonlinear preheating dynamics show specific features of this intermediate stage: occupation numbers of the scalar particles are peaked, scalar fields become significantly non-gaussian and the field dynamics become chaotic and irreversible. Visualization of the field dynamics in configuration space reveals that nonlinear interactions generate non-gaussian inflaton inhomogeneities with very fast growing amplitudes. The peaks of the inflaton inhomogeneities coincide with the peaks of the scalar field(s) produced by parametric resonance. When the inflaton peaks reach their maxima, they stop ...

  18. Preheating with Trilinear Interactions: Tachyonic Resonance

    CERN Document Server

    Dufaux, J F; Kofman, L; Peloso, M; Podolsky, D

    2006-01-01

    We investigate the effects of bosonic trilinear interactions in preheating after chaotic inflation. A trilinear interaction term allows for the complete decay of the massive inflaton particles, which is necessary for the transition to radiation domination. We found that typically the trilinear term is subdominant during early stages of preheating, but it actually amplifies parametric resonance driven by the four-legs interaction. In cases where the trilinear term does dominate during preheating, the process occurs through periodic tachyonic amplifications with resonance effects, which is so effective that preheating completes within a few inflaton oscillations. We develop an analytic theory of this process, which we call tachyonic resonance. We also study numerically the influence of trilinear interactions on the dynamics after preheating. The trilinear term eventually comes to dominate after preheating, leading to faster rescattering and thermalization than could occur without it. Finally, we investigate the...

  19. Clinical applications of preheated hybrid resin composite.

    Science.gov (United States)

    Rickman, L J; Padipatvuthikul, P; Chee, B

    2011-07-22

    This clinical article describes and discusses the use of preheated nanohybrid resin composite for the placement of direct restorations and luting of porcelain laminate veneers. Two clinical cases are presented. Preheating hybrid composite decreases its viscosity and film thickness offering the clinician improved handling. Preheating also facilitates the use of nanohybrid composite as a veneer luting material with relatively low polymerisation shrinkage and coefficient of thermal expansion compared to currently available resin luting cements.

  20. The superconductor-metal quantum phase transition in ultra-narrow wires

    Science.gov (United States)

    Del Maestro, Adrian Giuseppe

    We present a complete description of a zero temperature phase transition between superconducting and diffusive metallic states in very thin wires due to a Cooper pair breaking mechanism originating from a number of possible sources. These include impurities localized to the surface of the wire, a magnetic field orientated parallel to the wire or, disorder in an unconventional superconductor. The order parameter describing pairing is strongly overdamped by its coupling to an effectively infinite bath of unpaired electrons imagined to reside in the transverse conduction channels of the wire. The dissipative critical theory thus contains current reducing fluctuations in the guise of both quantum and thermally activated phase slips. A full cross-over phase diagram is computed via an expansion in the inverse number of complex components of the superconducting order parameter (equal to one in the physical case). The fluctuation corrections to the electrical and thermal conductivities are determined, and we find that the zero frequency electrical transport has a non-monotonic temperature dependence when moving from the quantum critical to low temperature metallic phase, which may be consistent with recent experimental results on ultra-narrow MoGe wires. Near criticality, the ratio of the thermal to electrical conductivity displays a linear temperature dependence and thus the Wiedemann-Franz law is obeyed. We compute the constant of proportionality in a systematic expansion and find a universal and experimentally verifiable fluctuation correction to the Lorenz number. In the presence of quenched disorder, a novel algorithm is developed to solve the self-consistency condition arising when the number of complex order parameter components is taken to be large. In this limit, we find striking evidence for the flow to infinite randomness, and observe dynamically activated scaling consistent with predictions from the strong disorder renormalization group. Moreover, the infinite

  1. Hill crossing during preheating after hilltop inflation

    CERN Document Server

    Antusch, Stefan; Orani, Stefano

    2015-01-01

    In 'hilltop inflation', inflation takes place when the inflaton field slowly rolls from close to a maximum of its potential (i.e. the 'hilltop') towards its minimum. When the inflaton potential is associated with a phase transition, possible topological defects produced during this phase transition, such as domain walls, are efficiently diluted during inflation. It is typically assumed that they also do not reform after inflation, i.e. that the inflaton field stays on its side of the 'hill', finally performing damped oscillations around the minimum of the potential. In this paper we study the linear and the non-linear phases of preheating after hilltop inflation. We find that the fluctuations of the inflaton field during the tachyonic oscillation phase grow strong enough to allow the inflaton field to form regions in position space where it crosses 'over the top of the hill' towards the 'wrong vacuum'. We investigate the formation and behaviour of these overshooting regions using lattice simulations: Rather t...

  2. Fuel preheater for diesel engines

    Energy Technology Data Exchange (ETDEWEB)

    Crossett, J.J.; Crossett, M.C.

    1987-10-13

    A unit for preheating fuel for diesel engines is described having an engine coolant system and a lubrication system utilizing a flowable lubricant. The unit comprises a housing providing a fluid-tight enclosure, a heat exchange coil positioned in and spaced above the bottom of the enclosure and having loops providing a continuous path for the flow of the fuel to be heated. The heat exchange coil has at least one foot of length for each 25 cubic inches of volume of the enclosure and a diesel fuel outlet in the housing connected to one end of the heat exchange coil, a diesel fuel outlet in the housing and connected to the other end of the heat exchange coil, an inlet in the housing for connection of the interior of the enclosure surrounding the coil to a source of a hot heat exchange medium in a diesel engine so as to provide a source of heat for heating the heat exchange coil. An outlet near the top of the housing provides for return of the heat exchange medium to a diesel engine, and spray tube means extend horizontally from the inlet for the heat exchange medium and along the bottom of the housing beneath substantially the entire length of the heat exchange coil. The means have upwardly directed openings to provide for discharge of the heat exchange medium toward the coil and agitation of the heat exchange medium in the enclosure around and over the heat exchange coil.

  3. Characterization of preheated and non-preheated HY-80 steel weldments by transmission electron microscopy

    OpenAIRE

    Clark, David Richard

    1983-01-01

    Approved for public release; distribution in unlimited. Preheating HY-80 steel weldments is standard procedure, but it is an expensive and time consuming step in the fabrication of hull structures. The microstructures and hardness profiles of both a preheated (250 F--121 C) and a non-preheated (32 F--0 C) HY-80 steel weldment were studied to provide information and allow comparisons of the microstructural transformations that occur in the heat affected zone during shielded metal arc weldin...

  4. Dynamics of Symmetry Breaking and Tachyonic Preheating

    CERN Document Server

    Felder, G; Greene, P B; Kofman, L A; Linde, Andrei D; Tkachev, Igor I; Felder, Gary; Garcia-Bellido, Juan; Greene, Patrick B.; Kofman, Lev; Linde, Andrei; Tkachev, Igor

    2001-01-01

    We reconsider the old problem of the dynamics of spontaneous symmetry breaking using 3d lattice simulations, and develop a theory of tachyonic preheating, which occurs due to the spinodal instability of the scalar field. Tachyonic preheating is so efficient that symmetry breaking typically completes within a single oscillation of the field distribution as it rolls towards the minimum of its effective potential. As an application of this theory we consider preheating in the hybrid inflation scenario, including SUSY-motivated F-term and D-term inflationary models. We show that preheating in hybrid inflation is typically tachyonic and the stage of oscillations of a homogeneous component of the scalar fields driving inflation ends after a single oscillation. Our results may also be relevant for the theory of the formation of disoriented chiral condensates in heavy ion collisions.

  5. Preheating after Small-Field Inflation

    CERN Document Server

    Brax, Philippe; Mariadassou, Sophie

    2010-01-01

    Whereas preheating after chaotic and hybrid inflation models has been abundantly studied in the literature, preheating in small field inflation models, where the curvature of the inflaton potential is negative during inflation, remains less explored. In these models, a tachyonic instability at the end of inflation leads to a succession of exponentially large increases and \\emph{decreases} of the inflaton fluctuations as the inflaton condensate oscillates around the minimum of its potential. The net effect is a competition between low-momentum modes which grow and decrease significantly, and modes with higher momenta which grow less but also decrease less. We develop an analytical description of this process, which is analogous to the quantum mechanical problem of tunneling through a volcano-shaped potential. Depending on the parameters, preheating may be so efficient that it completes in less than one oscillation of the inflaton condensate. Preheating after small field inflation may also be followed by a long...

  6. Narrow gap TIG and electron beam weld inspection in austenitic stainless steel using pulse echo, TOFD and phased array ultrasonics

    Energy Technology Data Exchange (ETDEWEB)

    Quirk, K.P.; Turner, J.L. [Phoenix Inspection Systems Limited, Warrington (United Kingdom)

    2004-07-01

    'Full-text:' Narrow gap Tungsten Inert Gas (TIG) and Electron Beam (EB) welding techniques are being considered for the splice joint welds on the austenitic stainless steel Vacuum Vessel in the next generation of experimental Fusion Power stations under the ITER programme. Under the programme there is a requirement to develop automated ultrasonic NDT techniques to inspect material up to 60 mm thick in both weld types. These narrow welds are difficult to inspect because of the steep fusion faces made more difficult in this project by the beam scattering effects of austenitic stainless steel welds and the very limited access from only one side of the vessel. The paper details the development of the combined Pulse Echo, TOFD and Phased Array techniques on behalf of ITER. The authors describe the philosophy behind the inspections, results and possible transfer of the technology to other sectors of industry. (author)

  7. Pre-heating mitigates composite degradation

    Directory of Open Access Journals (Sweden)

    Jessika Calixto da SILVA

    2015-12-01

    Full Text Available ABSTRACT Dental composites cured at high temperatures show improved properties and higher degrees of conversion; however, there is no information available about the effect of pre-heating on material degradation. Objectives This study evaluated the effect of pre-heating on the degradation of composites, based on the analysis of radiopacity and silver penetration using scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS. Material and Methods Thirty specimens were fabricated using a metallic matrix (2x8 mm and the composites Durafill VS (Heraeus Kulzer, Z-250 (3M/ESPE, and Z-350 (3M/ESPE, cured at 25°C (no pre-heating or 60°C (pre-heating. Specimens were stored sequentially in the following solutions: 1 water for 7 days (60°C, plus 0.1 N sodium hydroxide (NaOH for 14 days (60°C; 2 50% silver nitrate (AgNO3 for 10 days (60°C. Specimens were radiographed at baseline and after each storage time, and the images were evaluated in gray scale. After the storage protocol, samples were analyzed using SEM/EDS to check the depth of silver penetration. Radiopacity and silver penetration data were analyzed using ANOVA and Tukey’s tests (α=5%. Results Radiopacity levels were as follows: Durafill VSZ-350>Z-250 (p<0.05. After storage in water/NaOH, pre-heated specimens presented higher radiopacity values than non-pre-heated specimens (p<0.05. There was a lower penetration of silver in pre-heated specimens (p<0.05. Conclusions Pre-heating at 60°C mitigated the degradation of composites based on analysis of radiopacity and silver penetration depth.

  8. Compensation of distant phase-distorting layers. I. Narrow-field-of-view adaptive receiver system.

    Science.gov (United States)

    Yu, Miao; Vorontsov, Mikhail A

    2004-09-01

    We analyze various scenarios of adaptive wave-front phase-aberration correction in optical-receiver-type systems when inhomogeneties of the wave propagation medium are either distributed along the propagation path or localized in a few thin layers remotely located from the receiver telescope pupil. Phase-aberration compensation is performed with closed-loop control architectures based on decoupled stochastic parallel gradient descent, stochastic parallel gradient descent, and phase conjugation control algorithms. Both receiver system aperture diffraction effects and the effect of wave-front corrector position on phase-aberration compensation efficiency are analyzed.

  9. Investigation on preheating process in SLS machine

    Institute of Scientific and Technical Information of China (English)

    李湘生; 史玉升; 莫健华; 黄树槐

    2001-01-01

    Selective laser sintering (SLS) is an important Rapid Prototyping method because its wide range of materials. The powder is fused and processed into a part because it is heated in the process. Preheating of powder on the surface of powder bed is a one important process which is a guarantee by which parts can be successfully fabricated and influences accuracy of parts fabricated in SLS technology. The uniformity of temperature on powder bed influences accuracy and performance of parts. It is necessary to understand the influences of the parameters of preheating set on uniformity of temperature on surface of powder bed. This paper analyzes general preheating process of irradiator for the preheating of powder on the surface of powder bed during SLS processing,and investigates influences of the flux density on the temperature field on the top surface of powder bed. The models of distribution of flux density and the distribution of surface temperature of powder bed are presented.The result predicted according to the models is reasonably consistent with experimental result. This model plays important role in design of preheating set and control of SLS processing. It is concluded that the uniformity of temperature field on the powder bed is determined mostly by the geometry of heating component and its fix location and the flux density is inverse proportional to the highness.

  10. The Development of Equilibrium After Preheating

    CERN Document Server

    Kofman, L A

    2001-01-01

    We present a fully nonlinear study of the development of equilibrium after preheating. Preheating is the exponentially rapid transfer of energy from the nearly homogeneous inflaton field to fluctuations of other fields and/or the inflaton itself. This rapid transfer leaves these fields in a highly nonthermal state with energy concentrated in infrared modes. We have performed lattice simulations of the evolution of interacting scalar fields during and after preheating for a variety of inflationary models. We have formulated a set of generic rules that govern the thermalization process in all of these models. Notably, we see that once one of the fields is amplified through parametric resonance or other mechanisms it rapidly excites other coupled fields to exponentially large occupation numbers. These fields quickly acquire nearly thermal spectra in the infrared, which gradually propagates into higher momenta. Prior to the formation of total equilibrium, the excited fields group into subsets with almost identica...

  11. Temperature equilization in the Luetzkendorf preheater

    Energy Technology Data Exchange (ETDEWEB)

    1943-01-30

    Suggestions are offered for improvement to attain more nearly uniform temperature distribution in the preheater inlet and outlet as well as for improvement of a loss of pressure in heating gas for raising the efficiency of the heating gas blower. The evaluation of the operating conditions from the standpoint of the heating gas were made in the hydrogenation works of Poelitz, in 1939 with the preheater constructed on the Ludwigshafen plan, and in Luetzkendorf on the preheater of the Leuna model. Both preheaters had two Schiele heating gas blowers of the type 1160. Operating conditions involving hairpin tubes, temperatures, resistance, volume, piping, pressure, and heat conduction were given for both plants. A sketch for the heating gas movement was mentioned in the report but was not included. Recommendations on the use of a new blower were given. Some of these were reducing the yield to 90,000 cubic meters per hour and using the same motors. The distribution of the amounts and of the temperature drop of the gas and of the material of the hairpins were given.

  12. Metalorganic chemical vapor phase epitaxy of narrow-band distributed Bragg reflectors realized by GaN:Ge modulation doping

    Science.gov (United States)

    Berger, Christoph; Lesnik, Andreas; Zettler, Thomas; Schmidt, Gordon; Veit, Peter; Dadgar, Armin; Bläsing, Jürgen; Christen, Jürgen; Strittmatter, André

    2016-04-01

    We report on metalorganic vapor phase epitaxy (MOVPE) of distributed Bragg reflectors (DBR) applying a periodic modulation of the GaN doping concentration only. The doping modulation changes the refractive index of GaN via the Burstein-Moss-effect. MOVPE growth of highly doped GaN:Ge and modulation of the dopant concentration by at least two orders of magnitude within few nanometers is required to achieve a refractive index contrast of 2-3%. Such modulation characteristic is achieved despite the presence of Ge memory effects and incorporation delay. We realized DBRs with up to 100 layer pairs by combining GaN:Ge with a nominal doping concentration of 1.6×1020 cm-3 as low-refractive index material with unintentionally doped GaN as high-refractive index layer. Scanning transmission electron microscope images reveal DBR structures with abrupt interfaces and homogenous layer thicknesses in lateral and vertical direction. Reflectance measurements of DBRs designed for the blue and near UV-spectral region show a narrow stopband with a maximum reflectivity of 85% at 418 nm and even 95% at 370 nm. InGaN/GaN multi-quantum well structures grown on top of such DBRs exhibit narrow emission spectra with linewidths below 3 nm and significantly increased emission intensity.

  13. Pre-heating in the framework of massive gravity

    Directory of Open Access Journals (Sweden)

    Debaprasad Maity

    2016-09-01

    Full Text Available In this paper we propose a mechanism of natural pre-heating of our universe by introducing an inflaton field dependent mass term for the gravitational wave for a specific class of massive gravity theory. For any single field inflationary model, the inflaton must go through the oscillatory phase after the end of inflation. As has recently been pointed out, if the gravitational fluctuation has inflaton dependent mass term, there will be a resonant amplification of the amplitude of the gravitational wave during the oscillatory phase of inflaton. Because of this large enhancement of the amplitude of the gravitational wave due to parametric resonance, we show that universe can naturally go through the pre-reheated phase with minimally coupled matter field. Therefore, during the reheating phase, there is no need to introduce any arbitrary coupling between the matter field and the inflaton.

  14. Laser Phase Determination and Transfer Function to Directly Measure the Temporal Structure of a Narrow Bandwidth Attosecond EUV Pulse

    Institute of Scientific and Technical Information of China (English)

    GE Yu-Cheng

    2006-01-01

    A laser phase determination method and a transfer function that includes a proportional term of a measured photoelectron energy spectrum are presented to directly measure the detailed temporal structure of a narrow bandwidth attosecond extreme-ultraviolet (EUV) pulse. The method is based on the spectrum measurement of an electron generated by EUV photo-ionization interacting with a femtosecond laser field. The results of the study suggest that measurements should be taken at 0° or 180° with respect to the linear laser polarization. The method has a temporal measurement range of about half a laser oscillation period. The temporal resolution also depends on the jitter and control precision of the laser and EUV pulses.

  15. Inductive Preheating in Laser Beam Welding of Multimaterial Joints of 22MnB5 and AA6016

    Science.gov (United States)

    Kügler, H.; Vollertsen, F.

    Inductive preheating is well known as possibility to heat ferromagnetic materials. In brazing preheating causes an improvement of wetting quality, e.g. smaller wetting angles and longer wetting lengths. In this paper inductive preheating is used to support a laser beam hybrid joining process. Aluminum AA6016 is molten in order to wet the surface of AlSi- coated steel 22MnB5. Investigations on the influence of preheating on wetting characteristics and intermetallic phase seam formation were carried out. Strength values up to 230 MPa have been measured in tensile shear tests. Fraction zone occurs in the aluminum base material indicating uncritical thickness of the intermetallic phase seam at the interface.

  16. Recent Advances in Electrical Resistance Preheating of Aluminum Reduction Cells

    Science.gov (United States)

    Ali, Mohamed Mahmoud; Kvande, Halvor

    2017-02-01

    There are two mainpreheating methods that are used nowadays for aluminum reduction cells. One is based on electrical resistance preheating with a thin bed of small coke and/or graphite particles between the anodes and the cathode carbon blocks. The other is flame preheating, where two or more gas or oil burners are used. Electrical resistance preheating is the oldest method, but is still frequently used by different aluminum producers. Many improvements have been made to this method by different companies over the last decade. In this paper, important points pertaining to the preparation and preheating of these cells, as well as measurements made during the preheating process and evaluation of the performance of the preheating, are illustrated. The preheating times of these cells were found to be between 36 h and 96 h for cell currents between 176 kA and 406 kA, while the resistance bed thickness was between 13 mm and 60 mm. The average cathode surface temperature at the end of the preheating was usually between 800°C and 950°C. The effect of the preheating methods on cell life is unclear and no quantifiable conclusions can be drawn. Some works carried out in the mathematical modeling area are also discussed. It is concluded that there is a need for more studies with real situations for preheated cells on the basis of actual measurements. The expected development in electrical resistance preheating of aluminum reduction cells is also summarized.

  17. Pre-heating mitigates composite degradation.

    Science.gov (United States)

    Silva, Jessika Calixto da; Rogério Vieira, Reges; Rege, Inara Carneiro Costa; Cruz, Carlos Alberto dos Santos; Vaz, Luís Geraldo; Estrela, Carlos; Castro, Fabrício Luscino Alves de

    2015-01-01

    Dental composites cured at high temperatures show improved properties and higher degrees of conversion; however, there is no information available about the effect of pre-heating on material degradation. Objectives This study evaluated the effect of pre-heating on the degradation of composites, based on the analysis of radiopacity and silver penetration using scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS). Material and Methods Thirty specimens were fabricated using a metallic matrix (2x8 mm) and the composites Durafill VS (Heraeus Kulzer), Z-250 (3M/ESPE), and Z-350 (3M/ESPE), cured at 25°C (no pre-heating) or 60°C (pre-heating). Specimens were stored sequentially in the following solutions: 1) water for 7 days (60°C), plus 0.1 N sodium hydroxide (NaOH) for 14 days (60°C); 2) 50% silver nitrate (AgNO3) for 10 days (60°C). Specimens were radiographed at baseline and after each storage time, and the images were evaluated in gray scale. After the storage protocol, samples were analyzed using SEM/EDS to check the depth of silver penetration. Radiopacity and silver penetration data were analyzed using ANOVA and Tukey's tests (α=5%). Results Radiopacity levels were as follows: Durafill VSZ-350>Z-250 (pheated specimens presented higher radiopacity values than non-pre-heated specimens (pheated specimens (pheating at 60°C mitigated the degradation of composites based on analysis of radiopacity and silver penetration depth.

  18. Spectroscopic Measurements of Target Preheating on OMEGA

    Energy Technology Data Exchange (ETDEWEB)

    Elton, R.C.; Griem, H.R.; Iglesias, E.J.

    2000-02-28

    The preheating of laser-heated microballoon targets has been measured by time-resolved x-ray and extreme ultraviolet (euv) spectroscopy on the 30 kJ, 351 nm, 60-beam laser-fusion system at the University of Rochester Laboratory for Laser Energetics. Thin coatings of aluminum overcoated with magnesium served as indicators. both the sequence of the x-ray line emission and the intensity of euv radiation were used to determine a preheating peaking at {approx} 10 ns prior to onset of the main laser pulse, with a power density {approx_equal}1% of the main pulse. The measurements are supported by numerical modeling. Further information is provided by absorption spectra from the aluminum coating, backlighted by continuum from the heated surface. The exact source of the preheating energy remains unknown at present, but most likely arrives from early laser leakage through the system. The present target diagnostic is particularly useful when all beams cannot be monitored directly at all laser wavelengths.

  19. Metric-torsion preheating: cosmic dynamo mechanism?

    CERN Document Server

    de Andrade, L C Garcia

    2014-01-01

    Earlier Bassett et al [Phys Rev D 63 (2001) 023506] investigated the amplification of large scale magnetic fields during preheating and inflation in several different models. They argued that in the presence of conductivity resonance effect is weakened. From a dynamo equation in spacetimes endowed with torsion recently derived by Garcia de Andrade [Phys Lett B 711: 143 (2012)] it is shown that a in a universe with pure torsion in Minkowski spacetime the cosmological magnetic field is enhanced by ohmic or non-conductivity effect, which shows that the metric-torsion effects is worth while of being studied. In this paper we investigated the metric-torsion preheating perturbation, which leads to the seed cosmological magnetic field in the universe with torsion is of the order of $B_{seed}\\sim{10^{-37}Gauss}$ which is several orders of magnitude weaker than the decoupling value obtained from pure metric preheating of $10^{-15}Gauss$. Despite of the weakness of the magnetic field this seed field may seed the galact...

  20. Effect of preheating on potato texture.

    Science.gov (United States)

    Andersson, A; Gekas, V; Lind, I; Oliveira, F; Oste, R

    1994-01-01

    Preheating potatoes at 50 to 80 degrees C has a firming effect on the cooked potato tissue. This effect is particularly pronounced at a preheating temperature of 60 to 70 degrees C followed by cooling. Several theories have been presented in the literature to explain this firming effect: retrogradation of starch, leaching of amylose, stabilization of the middle lamellae and cell walls by the activation of the pectin methylesterase (PME) enzyme, and by the release of calcium from gelatinized starch and the formation of calcium bridges between pectin molecules. Most probably, none of these theories alone can explain the phenomenon and more than one mechanism seems to be involved. Some of these mechanisms seem to be interdependent. As an example, calcium could be considered as a link all the way through release after starch gelatinization to cross-linking pectin substances in the cell wall and the middle lamellae, which has been demethylated by the PME enzyme. More research and "clear cut" experiments are needed in order to elucidate the role of each mechanism, especially which of them is the main contributor to the process of firming. Most probably, the calcium-pectin-PME mechanism plays a secondary role, that is, it only retards the collapse of the tissue structure that would otherwise occur during the final heating without preheating, and it is not the main factor of firmness.

  1. Microstructures and properties of non-preheated hardfacing welding

    Institute of Scientific and Technical Information of China (English)

    Yang Shanglei; Zou Zengda; Lü Xueqin; Lou Songnian

    2007-01-01

    A new type of non-preheated hardfacing electrode was developed using H08A as the core and the coat contents including ferrotitanium, ferrovanadium, graphite, rutile etc. The microstructures and properties of hardfacing metal were systematically researched. The results show the hardness of hardfacing metal increases with increasing of ferrotitanium, ferrovanadium, graphite in the coat, but the crack resistance and processing weldability become worse. The carbides formed by arc metallurgic reaction are uniformly dispersed in the matrix structure. The phases of hardfacing metal consist of α-Fe, γ-Fe, VC, TiC and Fe3C. The carbides are compression aggregation of TiC and VC, and their appearances present irregular block. The matrix microstructure of hardfacing metal is lath martensite. The hardfacing layers with better crack resistance and wearability are achieved and no visible cracks occur when using non-preheated electrode in continuous welding process. Hardness of hardfacing metal is more than 60HRC, and its relative wearability is five times of wearability of D667 electrode in abrasive wear test.

  2. Phase diagrams for a binary mixture confined in narrow slitlike pores with energetically heterogeneous walls from a lattice mean-field approach

    CERN Document Server

    Martínez, A; Pizio, O; Sokolowski, S

    2003-01-01

    We investigate the phase behaviour of binary symmetric lattice fluid, exhibiting partial demixing in slitlike pores with heterogeneous walls. The calculations are carried out assuming a cubic lattice with vacancies and a model for heterogeneity similar to that of Roecken and Tarazona (1996 J. Chem. Phys. 105 2034). We concentrate on the effects of surface heterogeneity on the scenarios for the phase transformations. It is shown that for wide enough pores a step-wise condensation occurs between demixed phases. For narrower pores the lambda-line may cross the boundaries of the bridge phase and multiple critical end points appear. In such cases, at low temperatures the bridge phase formation occurs between demixed phases, at intermediate temperature it involves mixed and demixed phases and finally it becomes a transition between two demixed phases again.

  3. Ammonium bisulfate formation temperature in a bench-scale single-channel air preheater

    Energy Technology Data Exchange (ETDEWEB)

    J. Menasha; D. Dunn-Rankin; L. Muzio; J. Stallings [University of California Irvine, Irvine, CA (United States). Department of Mechanical and Aerospace Engineering

    2011-07-15

    Ammonium bisulfate (ABS) forms in coal-fired power plant exhaust systems when ammonia slip from the NOx control system reacts with the sulfur oxides and water in the flue gas. The critical temperature range for ABS formation occurs in the air preheater, where ABS is known to cause corrosion and pluggage that can require unplanned outages and expensive cleaning. To develop mitigation strategies for the deleterious effects of ABS in air preheaters, it is important to know its formation temperature and deposition process. This paper describes a bench-scale experimental simulation of a single-channel air preheater, with the appropriate temperature gradient, used in conjunction with simulated coal combustion flue gas, including sulfur oxides, ammonia, and water vapor, to investigate the formation of ABS. Formation was observed optically, and the formation temperature, as well as deposition characteristics for a realistic range of reactant concentrations are presented and compared with previous studies on ABS formation. This study presents data at realistic concentrations not earlier tested, and the reported data has smaller experimental uncertainty than previously obtained. We found that the measured ABS formation temperatures under air preheater channel conditions lies between the temperatures reported by others, and is in the range of 500-520 K for typical flue gas concentrations of ammonia and sulfur oxide species. The results also show that, at least for this experimental configuration, ABS forms predominantly as an aerosol in the gas phase rather than as a condensate on the channel walls. 13 refs., 13 figs., 2 tabs.

  4. Ions Preheated in 3He-Rich Solar Particle Events

    Institute of Scientific and Technical Information of China (English)

    王德焴

    2003-01-01

    A wave-particle resonance absorption model in the two-ion plasma is suggested in explanation to the coronal ions preheating in 3He-rich solar particle events. It is found that 3He and Fe ions are preferably preheated by the ion-ion hybrid waves at their fundamental and second harmonic ion cyclotron frequencies, respectively.

  5. Bringing coal preheating in drum dryers to a commercial level

    Energy Technology Data Exchange (ETDEWEB)

    Babanin, B.I.; Proushin, Yu.E.; Dinel' t, V.M.; Nikolaeva, V.Z.; Shabarshova, Yu.V.; Patrushev, A.N.; Vodop' yanov, A.G.; Vlasov, V.S.; Sementin, V.P.

    1988-10-01

    Discusses operation of a system for coal charge preheating used in Western Siberia since 1965. It is the first coal preheating system constructed in the USSR. The following aspects of system operation are discussed: composition of combustion gases used for coal drying, drying temperature, consumption rate of combustion gases depending on coal moisture content, flue gas recirculation system, transport and storage of dried coal, methods for dust separation (wet and dry), air pollution from coal dryers, and efficiency of air pollution control. Operation of the coal preheating system shows that one-stage coal drying and preheating is economic but associated with increased investment (construction cost) and with increased coal comminution. Large one-stage dryers also cause irregular coal preheating depending on distribution of coal grain size (with overheating of coal fines). Recommendations for design modifications of one-stage dryers are made. 3 refs.

  6. Fate of Electroweak Vacuum during Preheating

    CERN Document Server

    Ema, Yohei; Nakayama, Kazunori

    2016-01-01

    Our electroweak vacuum may be metastable in light of the current experimental data of the Higgs/top quark mass. If this is really the case, high-scale inflation models require a stabilization mechanism of our vacuum during inflation. A possible candidate is the Higgs-inflaton/-curvature coupling because it induces an additional mass term to the Higgs during the slow roll regime. However, after the inflation, the additional mass term oscillates, and it can potentially destabilize our electroweak vacuum via production of large Higgs fluctuations during the inflaton oscillation era. In this paper, we study whether or not the Higgs-inflaton/-curvature coupling can save our vacuum by properly taking account of Higgs production during the preheating stage. We put upper bounds on the Higgs-inflaton/-curvature coupling, and discuss possible dynamics that might relax them.

  7. QUENCH STUDIES AND PREHEATING ANALYSIS OF SEAMLESS

    Energy Technology Data Exchange (ETDEWEB)

    Palczewski, Ari [JLAB; Geng, Rongli [JLAB; Eremeev, Grigory [JLAB

    2013-09-01

    One of the alternative manufacturing technologies for SRF cavities is hydroforming from seamless tubes. Although this technology has produced cavities with gradient and Q-values comparable to standard EBW/EP cavities, a few questions remain. One of these questions is whether the quench mechanism in hydroformed cavities is the same as in standard electron beam welded cavities. Towards this effort Jefferson Lab performed quench studies on 2 9 cell seamless hydroformed cavities. These cavities include DESY's - Z163 and Z164 nine-cell cavities hydroformed at DESY. Initial Rf test results Z163 were published in SRF2011. In this report we will present post JLAB surface re-treatment quench studies for each cavity. The data will include OST and T-mapping quench localization as well as quench location preheating analysis comparing them to the observations in standard electron beam welded cavities.

  8. Application of the Separate Universe Approach to Preheating

    CERN Document Server

    Tanaka, T; Tanaka, Takahiro; Bassett, Bruce

    2003-01-01

    The dynamics of preheating after inflation has not been clearly understood yet.In particular, the issue of the generation of metric perturbations during preheating on super-horizon scale is still unsettled. Large scale perturbations may leave an imprint on the cosmic microwave background, or may become seeds for generation of primordial black holes. Hence, in order to make a connection between the particle physics models and cosmological observations, understanding the evolution of super-Hubble scale perturbations during preheating is important. Here, we propose an alternative treatment to handle this issue based on the so-called separate universe approach, which suggests less efficient amplification of super-Hubble modes during preheating than was expected before. We also point out an important issue which may have been overlooked in previous treatments.

  9. Equation of state and Beginning of Thermalization After Preheating

    CERN Document Server

    Podolsky, D I; Kofman, L; Peloso, M; Podolsky, Dmitry I.; Felder, Gary N.; Kofman, Lev; Peloso, Marco

    2006-01-01

    We study the out-of-equilibrium nonlinear dynamics of fields after post-inflationary preheating. During preheating, the energy in the homogeneous inflaton is exponentially rapidly transfered into highly occupied out-of-equilibrium inhomogeneous modes, which subsequently evolve towards equilibrium. The infrared modes excited during preheating evolve towards a saturated distribution long before thermalization completes. We compute the equation of state during and immediately after preheating. It rapidly evolves towards radiation domination long before the actual thermal equilibrium is established. The exact time of this transition is a non-monotonic function of the coupling between the inflaton and the decay products, and it varies only very weakly (around 10^(-35) s) as this coupling changes over several orders of magnitude. This result is applied to refine the relation between the number of efoldings N and the physical wavelength of perturbations generated during inflation. We also discuss the implications fo...

  10. Anisotropies in the gravitational wave background from preheating.

    Science.gov (United States)

    Bethke, Laura; Figueroa, Daniel G; Rajantie, Arttu

    2013-07-05

    We investigate the anisotropies in the gravitational wave (GW) background produced at preheating after inflation. Using lattice field theory simulations of a massless preheating model, we show that the GW amplitude depends sensitively on the value of the decay product field χ coupled to the inflaton φ, with the only requisite that χ is light during inflation. We find a strong anisotropy in the amplitude of the GW background on large angular scales, the details of which strongly depend on the reheating dynamics. We expect similar conclusions for a wide class of inflationary models with light scalar fields. If future direct detection GW experiments are capable of detecting the GW produced by preheating, they should also be able to detect this effect. This could eventually provide a powerful way to distinguish between different inflationary and preheating scenarios.

  11. Gauge Field Preheating at the End of Inflation

    CERN Document Server

    Deskins, J Tate; Caldwell, Robert R

    2013-01-01

    Here we consider the possibility of preheating the Universe via the parametric amplification of a massless, U(1) abelian gauge field. We assume that the gauge field is coupled to the inflaton via a conformal factor with one free parameter. We present the results of high-resolution three-dimensional simulations of this model and show this mechanism efficiently preheats the Universe to a radiation-dominated final state.

  12. Laser Pre-Heat Studies for MagLIF with Z-Beamlet

    Science.gov (United States)

    Geissel, Matthias; Harvey-Thompson, Adam J.; Awe, T. J.; Gomez, M. R.; Harding, E.; Jennings, C.; Kimmel, M. W.; Knapp, P.; Peterson, K.; Schollmeier, M.; Sefkow, A. B.; Shores, J. E.; Sinars, D. B.; Slutz, S. A.; Smith, I. C.; Speas, C. S.; Vesey, R. A.; Porter, J. L.; Campbell, E. M.; Lewis, S. M.

    2015-11-01

    Magnetized Liner Inertial Confinement Fusion (MagLIF) relies on strong pre-heat of the fuel, typically hundreds of eV. Z-Beamlet delivers up to 4 kJ of laser energy to the target to achieve this goal. Over the last year, several experimental campaigns at the Pecos target area of Sandia's Z-Backlighter Facility and in the center section of the Z-Accelerator have been performed to investigate pre-heat. Primary objectives of these campaigns were the transmission through the laser entrance hole (LEH) in dependence of window thicknesses and focus parameters (including phase plate smoothing), as well as energy coupling to the gaseous fuel. The applied diagnostic suite included a wide range of time integrated and time-resolved X-ray imaging devices, spectrometers, backscatter monitors, a full-beam laser transmission calorimeter, and X-ray diodes.We present the findings of these studies, looking ahead towards a standard pre-heat platform. Sandia National Labs is a multi-program laboratory managed and operated by Sandia Corp., a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Dept. of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  13. Two-stage magneto-optical trapping and narrow-line cooling of $^6$Li atoms to high phase-space density

    CERN Document Server

    Sebastian, Jimmy; Li, Ke; Gan, Huat Chai Jaren; Li, Wenhui; Dieckmann, Kai

    2014-01-01

    We report an experimental study of peak and phase-space density of a two-stage magneto-optical trap (MOT) of 6-Li atoms, which exploits the narrower $2S_{1/2}\\rightarrow 3P_{3/2}$ ultra-violet (UV) transition at 323 nm following trapping and cooling on the more common D2 transition at 671 nm. The UV MOT is loaded from a red MOT and is compressed to give a high phase-space density up to $3\\times 10^{-4}$. Temperatures as low as 33 $\\mu$K are achieved on the UV transition. We study the density limiting factors and in particular find a value for the light-assisted collisional loss coefficient of $1.3 \\pm0.4\\times10^{-10}\\,\\textrm{cm}^3/\\textrm{s}$ for low repumping intensity.

  14. Narrow-linewidth chirped frequency comb from a frequency-shifted feedback Ti:sapphire laser seeded by a phase-modulated single-frequency fiber laser.

    Science.gov (United States)

    Brandl, Matthias F; Mücke, Oliver D

    2010-12-15

    Frequency-shifted feedback (FSF) lasers have emerged as powerful tools for precision distance metrology. At the output of a Michelson interferometer, the detected rf spectra of the FSF laser light contain a length-dependent heterodyne beat signal whose linewidth ultimately limits the achievable accuracy of length measurements. Here, we demonstrate a narrow-linewidth chirped frequency comb from an FSF Ti:sapphire ring laser seeded by a phase-modulated, ultra-low-phase-noise, single-frequency fiber laser. We experimentally investigate the influence of the seed laser linewidth on the resulting width and shape of the length-dependent rf beat signal. An ultranarrow heterodyne beat linewidth of <20 Hz is observed.

  15. Synergistic effect of heat-shock and UV-irradiation on mitosis and protein synthesis in G2-phase plasmodia of Physarum polycephalum Schw--reduction in UV-induced mitotic delay in a preheat-shocked system.

    Science.gov (United States)

    Kumar, P R; Nair, R V

    1991-04-01

    The synergistic effect of UV irradiation and heat-shock during the last 3 hr of G2 phase of the cell cycle in the plasmodia of P. polycephalum, in terms of mitotic delay and inhibition of protein synthesis, has been evaluated. The mitotic delay due to both perturbers coordinately increased closer to mitosis. Maximum mitotic delay was obtained in plasmodia heat-shocked after UV irradiation, indicating the presence in this system of either a heat-labile mitogenic substance which is comparatively less susceptible to UV or a substance which is made more susceptible to hyperthermia by UV. A protective role for heat-shock applied before irradiation has been observed in that, radiation-induced mitotic delay is significantly reduced in this combination. There was severe inhibition of translation in all the perturbed classes. Organelle level effects which are independent of major protein synthetic activities or different levels of heat-shock protein production could be the reason for the lack of correlation between percentage inhibition of general protein synthesis and the extent of mitotic delay with respect to the two double-perturbed systems.

  16. Reheating and preheating in the simplest extension of Starobinsky inflation

    CERN Document Server

    van de Bruck, C; Paduraru, L E

    2016-01-01

    The epochs of reheating and preheating are studied in a simple extension of the Starobinsky inflationary model, which consists of an $R^2$--correction to the Einstein--Hilbert action and an additional scalar field. We find that if the $R^2$--correction at the end of inflation is dynamically important, it affects the expansion rate and as a consequence the reheating and preheating processes. While we find that the reheating temperature and duration of reheating are only slightly affected, the effect has to be taken into account when comparing the theory to data. In the case of preheating, the gravitational corrections can significantly affect the decay of the second field. Particle production is strongly affected for certain values of the parameters in the theory.

  17. High pressure annular two-phase flow in a narrow duct. Part 1: Local measurements in the droplet field, and Part 2: Three-field modeling

    Energy Technology Data Exchange (ETDEWEB)

    Trabold, T.A.; Kumar, R. [Lockheed Martin Corp., Schenectady, NY (United States)

    1999-07-01

    In Part 1, detailed measurements were made in a high pressure, adiabatic (boiled at the inlet) annular flow in a narrow, high aspect ratio duct using a gamma densitometer, hot-film anemometer and high-speed video photography. Measurements of void fraction, droplet frequency, velocity, drop size, and interfacial area concentration have been made to support the three field computational capability. An important aspect of this testing is the use of a modeling fluid (R-134a) in a vertical duct which permits visual access in annular flow. This modeling fluid accurately simulates the low liquid-to-vapor density ratio of steam-water flows at high pressures. These measurements have been taken in a narrow duct of hydraulic diameter 4.85 mm, and a cross-section aspect ratio of 22.5. However, the flow displays profiles of various shapes not only in the narrow dimension, but also in the width dimension. In particular, the shape of the droplet profiles depends on the entrained droplet flux from the edges in the vapor core. The average diameter from these profiles compare well with the models developed in the literature. Interfacial area concentration for these low density ratio flows is higher than the highest concentration reported for air-water flows. Video records show that along with the bow-shaped waves, three-dimensional {lambda}-shaped waves appear in annular flows for high flow rates. Part 2 outlines the development of a three-field modeling approach in annular flow and the predictive capability of an analysis code. Models have been developed here or adapted from the literature for the thin film near the wall as well as the droplets in the vapor core, and have been locally applied in a fully developed, two-phase adiabatic boiling annular flow in a duct heated at the inlet at high pressure. Numerical results have been obtained using these models that are required for the closure of the continuity and momentum equations. The two-dimensional predictions are compared with

  18. Gravity Waves from Tachyonic Preheating after Hybrid Inflation

    CERN Document Server

    Dufaux, Jean Francois; Kofman, Lev; Navros, Olga

    2008-01-01

    We study the stochastic background of gravitational waves produced from preheating in hybrid inflation models. We investigate different dynamical regimes of preheating in these models and we compute the resulting gravity wave spectra using analytical estimates and numerical simulations. We discuss the dependence of the gravity wave frequencies and amplitudes on the various potential parameters. We find that large regions of the parameter space leads to gravity waves that may be observable in upcoming interferometric experiments, including Advanced LIGO, but this generally requires very small coupling constants.

  19. Effects of extrusion-billet preheating on the microstructure and properties of Zr-2.5Nb pressure tube materials

    Energy Technology Data Exchange (ETDEWEB)

    Choubey, R.; Cann, C.D. [Atomic Energy of Canada Limited, Pinawa, Manitoba (Canada). Whiteshell Labs.; Aldridge, S.A. [Nu-Tech Precision Metals, Inc., Arnprior, Ontario (Canada); Theaker, J.R.; Coleman, C.E. [Atomic Energy of Canada Ltd., Chalk River, Ontario (Canada). Chalk River Labs.

    1996-12-31

    The effects of extrusion temperature and pre-heat soak time for billets on the mechanical properties of Zr-2.5Nb pressure tubes for CANDU reactors have been examined. The {beta}-quenched billets from a quadruple-melted ingot containing approximately 1,200 ppm of oxygen were extruded at 780, 815, and 850 C with pre-heat soak times of 15 to 300 min. The extruded hollows were finished by cold drawing (with a 28% reduction in area) and then stress relieving at 400 C. The {alpha}-phase grain structure, tensile strength, and fracture toughness properties were found to vary with the pre-heat temperature and soak time. All the materials were tough because embrittling impurities were absent. The tubes with 780 C preheat had a very fine and uniform {alpha}-grain structure, giving high strength and toughness at all soak times. The opposite was true for the 850 C soaks; the grain structure was coarse and inhomogeneous and the materials tended to be less strong and less touch. The tubes with the 815 C soaks showed intermediate values of strength and toughness. These variations in mechanical properties are discussed in terms of {alpha}-grain refinement and oxygen enrichment.

  20. Surface Characteristics of Machined NiTi Shape Memory Alloy: The Effects of Cryogenic Cooling and Preheating Conditions

    Science.gov (United States)

    Kaynak, Y.; Huang, B.; Karaca, H. E.; Jawahir, I. S.

    2017-07-01

    This experimental study focuses on the phase state and phase transformation response of the surface and subsurface of machined NiTi alloys. X-ray diffraction (XRD) analysis and differential scanning calorimeter techniques were utilized to measure the phase state and the transformation response of machined specimens, respectively. Specimens were machined under dry machining at ambient temperature, preheated conditions, and cryogenic cooling conditions at various cutting speeds. The findings from this research demonstrate that cryogenic machining substantially alters austenite finish temperature of martensitic NiTi alloy. Austenite finish ( A f) temperature shows more than 25 percent increase resulting from cryogenic machining compared with austenite finish temperature of as-received NiTi. Dry and preheated conditions do not substantially alter austenite finish temperature. XRD analysis shows that distinctive transformation from martensite to austenite occurs during machining process in all three conditions. Complete transformation from martensite to austenite is observed in dry cutting at all selected cutting speeds.

  1. High efficiency, narrow particle size distribution, sub-2 μm based macrocyclic glycopeptide chiral stationary phases in HPLC and SFC.

    Science.gov (United States)

    Barhate, Chandan L; Wahab, M Farooq; Breitbach, Zachary S; Bell, David S; Armstrong, Daniel W

    2015-10-22

    State of the art chiral chromatography still employs 3-5 μm bonded or immobilized chiral selectors in 10-25 cm columns. With the availability of 1.9 μm narrow particle size distribution (NPSD) silica, it is now possible to make ever shorter, high efficiency columns practical for sub-minute chiral separations. Three macrocyclic glycopeptides (teicoplanin, teicoplanin aglycone, and vancomycin) were bonded onto 1.9 μm NPSD particles. Such packed columns had ∼80% lower backpressure as compared to polydisperse (PD) 1.7 μm silica materials when using the same mobile phase. The decreased backpressure allowed for diminution of frictional heating and allowed for the use of the 1.9 μm NPSD particle based columns at high flow rates. The 1.9 μm NPSD particle based columns showed up to 190,000 plates m(-1) for chiral molecules and 210,000 plates m(-1) for achiral probes. Representative enantiomeric separations are shown for wide classes of compounds, including different types of amino acids, β-blockers, and pharmaceutically important heterocyclic compounds such as oxazolidinones. Applications in three liquid chromatography modes, namely, reversed phase, polar organic mode and normal phase chiral separations were shown with resolution values ranging from 1.5 to 5.7. Additionally, the same columns were used with supercritical fluid chromatography (SFC) for ultrafast separations.

  2. Bruce Unit 1 and 2 preheater condition assessment and refurbishment

    Energy Technology Data Exchange (ETDEWEB)

    King, P.; Machowski, C.; McGillivray, R. [Babcock and Wilcox Canada Ltd., Cambridge, ON (Canada); Durance, D. [Bruce Power, Tiverton, ON (Canada)

    2008-07-01

    Bruce Units 1 to 4 were shut down during the 1990s, largely as a consequence of tube degradation resulting from inappropriate steam generator secondary side water chemistries. Following a condition assessment, Bruce Power restarted Units 3 and 4 and is currently refurbishing Units 1 and 2. In order to assess the condition of the Unit 1 and Unit 2 preheaters and determine their suitability for extended operation, inspection, maintenance and assessment activities have been conducted. Eddy current and visual inspection have revealed vessels in generally good condition. Secondary side internals appear largely undergraded. Some tube to support fretting has been observed, and a number of tubes have been removed from service because of debris fretting concerns. To prepare for return to service, the primary side divider plates have been replaced and the tubes have been ID cleaned to restore the preheater to its original condition. This paper summarizes the inspection planning, findings, assessment for extended operation and maintenance activities undertaken. (author)

  3. A Model Independent Approach to (p)Reheating

    CERN Document Server

    Özsoy, Ogan; Sinha, Kuver; Watson, Scott

    2015-01-01

    In this note we propose a model independent framework for inflationary (p)reheating. Our approach is analogous to the Effective Field Theory of Inflation, however here the inflaton oscillations provide an additional source of (discrete) symmetry breaking. Using the Goldstone field that non-linearly realizes time diffeormorphism invariance we construct a model independent action for both the inflaton and reheating sectors. Utilizing the hierarchy of scales present during the reheating process we are able to recover known results in the literature in a simpler fashion, including the presence of oscillations in the primordial power spectrum. We also construct a class of models where the shift symmetry of the inflaton is preserved during reheating, which helps alleviate past criticisms of (p)reheating in models of Natural Inflation. Extensions of our framework suggest the possibility of analytically investigating non-linear effects (such as rescattering and back-reaction) during thermalization without resorting t...

  4. Theory and Numerics of Gravitational Waves from Preheating after Inflation

    CERN Document Server

    Dufaux, Jean Francois; Felder, Gary N; Kofman, Lev; Uzan, Jean-Philippe

    2007-01-01

    Preheating after inflation involves large, time-dependent field inhomogeneities, which act as a classical source of gravitational radiation. The resulting spectrum might be probed by direct detection experiments if inflation occurs at a low enough energy scale. In this paper, we develop a theory and algorithm to calculate, analytically and numerically, the spectrum of energy density in gravitational waves produced from an inhomogeneous background of stochastic scalar fields in an expanding universe. We derive some generic analytical results for the emission of gravity waves by stochastic media of random fields, which can test the validity/accuracy of numerical calculations. We contrast our method with other numerical methods in the literature, and then we apply it to preheating after chaotic inflation. In this case, we are able to check analytically our numerical results, which differ significantly from previous works. We discuss how the gravity wave spectrum builds up with time and find that the amplitude an...

  5. Preheating and Affleck-Dine leptogenesis after thermal inflation

    CERN Document Server

    Felder, G N; Park, W I; Stewart, E D; Felder, Gary N.; Kim, Hyunbyuk; Park, Wan-Il; Stewart, Ewan D.

    2007-01-01

    Previously, we proposed a model of low energy Affleck-Dine leptogenesis in the context of thermal inflation. The lepton asymmetry is generated at the end of thermal inflation, which occurs at a relatively low energy scale with the Hubble parameter somewhere in the range $1 \\keV \\lesssim H \\lesssim 1 \\MeV$. Thus Hubble damping will be ineffective in bringing the Affleck-Dine field into the lepton conserving region near the origin, leaving the possibility that the lepton number could be washed out. Previously, we suggested that preheating could damp the amplitude of the Affleck-Dine field allowing conservation of the lepton number. In this paper, we demonstrate numerically that preheating does efficiently damp the amplitude of the Affleck-Dine field and that the lepton number is conserved as the result. In addition to demonstrating a crucial aspect of our model, it also opens the more general possibility of low energy Affleck-Dine baryogenesis.

  6. Non-equilibrium Goldstone phenomenon in tachyonic preheating

    CERN Document Server

    Borsanyi, S; Sexty, D; Borsanyi, Sz.

    2003-01-01

    The dominance of the direct production of elementary Goldstone waves is demonstrated in tachyonic preheating by determining numerically the evolution of the dispersion relation, the equation of state and the kinetic power spectra for the angular degree of freedom of the complex matter field. The importance of the domain structure in the order parameter distribution for the quantitative understanding of the excitation mechanism is emphasized. Evidence is presented for the very early decoupling of the low-momentum Goldstone modes.

  7. Gauge-preheating and the end of axion inflation

    CERN Document Server

    Adshead, Peter; Scully, Timothy R; Sfakianakis, Evangelos I

    2015-01-01

    We study the onset of the reheating epoch at the end of axion-driven inflation where the axion is coupled to an Abelian, $U(1)$, gauge field via a Chern-Simons interaction term. We focus primarily on $m^2\\phi^2$ inflation and explore the possibility that preheating can occur for a range of coupling values consistent with recent observations and bounds on the overproduction of primordial black holes. We find that for a wide range of parameters preheating is efficient. In certain cases the inflaton is seen to transfer all its energy to the gauge fields within a few oscillations. We find that the gauge fields on sub-horizon scales end in an unpolarized state, due to the existence of strong rescattering between the inflaton and gauge modes. We also present a preliminary study of an axion monodromy model coupled to $U(1)$ gauge fields, seeing a similarly efficient preheating behavior as well as indications that the coupling strength has an effect on the creation of oscillons.

  8. Gravitational Waves from Preheating in M-flation

    CERN Document Server

    Ashoorioon, Amjad; Mann, Robert B; Oltean, Marius; Sheikh-Jabbari, M M

    2014-01-01

    Matrix inflation, or M-flation, is a string theory motivated inflationary model with three scalar field matrices and gauge fields in the adjoint representation of the $\\mathbf{U}(N)$ gauge group. One of these $3N^2$ scalars appears as the effective inflaton while the rest of the fields (scalar and gauge fields) can play the role of isocurvature fields during inflation and preheat fields afterwards. There is a region in parameter space and initial field values, "the hilltop region," where predictions of the model are quite compatible with the recent \\textit{Planck} data. We show that in this hilltop region, if the inflaton ends up in the supersymmetric vacuum, the model can have an embedded preheating mechanism. % only if inflation happens around the supersymmetric vacuum. % Couplings of the preheat modes are related to the inflaton self-couplings and therefore are known from the CMB data. Through lattice simulations performed using a symplectic integrator, we numerically compute the power spectra of gravitati...

  9. An analysis of metallurgical ladle preheating; Uma analise do processo de pre-aquecimento da panela de aciaria

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Eliana F. [Ouro Preto Univ., MG (Brazil). Escola de Minas; Figueira, Renato M. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Dept. de Engenharia Metalurgica

    1996-12-31

    An analysis of the pre-heating effects of the siderurgical ladle refractory lining on the steel making process is developed. The modeling is based essentially on the transient two-dimensional heat conduction equation, expressed in cylindrical coordinates, and also taking into account radiation and convection boundary conditions. The solution procedure is accomplished by means of an `ANSYS` F.E.M. scheme. The analysis enables the evaluation of the preheating influence on the other phases of the complete continuous casting process . The conditions which have to be used in the control of the whole process can be determined by this simulation, enabling the optimization of energy consumption, refractory lining wear, and holding time. (author) 10 refs., 6 figs.

  10. Low SO2 Emission Preheaters for Cement Production

    DEFF Research Database (Denmark)

    Rasmussen, Martin Hagsted

    showed that this figure could be between 90 kJ/mole and 140 kJ/mole, with a corresponding change of preexponential factors. The ability to predict emissions is very important in the design of cement plants. In this thesis the zone model concept has been applied to the modelling of the cyclone stages...... in a preheater tower. The idea is to account for the complex flow pattern in a cyclone stage by dividing it into zones, each zone having special features. In this manner the model can account for gas/solid heat exchange, gas/solid separation, different gas and solid residence times, etc. The model was evaluated...

  11. Parametric resonance of entropy perturbations in massless preheating

    Science.gov (United States)

    Moghaddam, Hossein Bazrafshan; Brandenberger, Robert H.; Cai, Yi-Fu; Ferreira, Elisa G. M.

    2015-07-01

    In this paper, we revisit the question of possible preheating of entropy modes in a two-field model with a massless inflaton coupled to a matter scalar field. Using a perturbative approximation to the covariant method we demonstrate that there is indeed a parametric instability of the entropy mode which then at second-order leads to exponential growth of the curvature fluctuation on super-Hubble scale. Back-reaction effects shut off the induced curvature fluctuations, but possibly not early enough to prevent phenomenological problems. This confirms previous results obtained using different methods and resolves a controversy in the literature.

  12. Preheating and entropy perturbations in axion monodromy inflation

    Energy Technology Data Exchange (ETDEWEB)

    McDonough, Evan; Moghaddam, Hossein Bazrafshan [Department of Physics, McGill University,Montréal, QC H3A 2T8 (Canada); Brandenberger, Robert H. [Department of Physics, McGill University,Montréal, QC H3A 2T8 (Canada); Institute for Theoretical Studies, ETH Zürich,CH-8092 Zürich (Switzerland)

    2016-05-04

    We study the preheating of gauge fields in a simple axion monodromy model and compute the induced entropy perturbations and their effect on the curvature fluctuations. We find that the correction to the spectrum of curvature perturbations has a blue spectrum with index n{sub s}=5/2. Hence, these induced modes are harmless for the observed structure of the universe. Since the spectrum is blue, there is the danger of overproduction of primordial black holes. However, we show that the observational constraints are easily satisfied.

  13. Preheating and Entropy Perturbations in Axion Monodromy Inflation

    CERN Document Server

    ,

    2016-01-01

    We study the preheating of gauge fields in a simple axion monodromy model and compute the induced entropy perturbations and their effect on the curvature fluctuations. We find that the correction to the spectrum of curvature perturbations has a blue spectrum with index $n_s = 5/2$. Hence, these induced modes are harmless for the observed structure of the universe. Since the spectrum is blue, there is the danger of overproduction of primordial black holes. However, we show that the observational constraints are easily satisfied.

  14. Measuring preheat in laser-drive aluminum using velocity interferometer system for any reflector: Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Hua; Fu, Sizu; Huang, Xiuguang; Wu, Jiang; Xie, Zhiyong; Zhang, Fan; Ye, Junjian; Jia, Guo; Zhou, Huazhen [Shanghai Institute of Laser Plasma, P.O. BOX 800-229, Shanghai 201800 (China)

    2014-08-15

    In this paper, we systematically study preheating in laser-direct-drive shocks by using a velocity interferometer system for any reflector (VISAR). Using the VISAR, we measured free surface velocity histories of Al samples over time, 10–70 μm thick, driven directly by a laser at different frequencies (2ω, 3ω). Analyzing our experimental results, we concluded that the dominant preheating source was X-ray radiation. We also discussed how preheating affected the material initial density and the measurement of Hugoniot data for high-Z materials (such as Au) using impedance matching. To reduce preheating, we proposed and tested three kinds of targets.

  15. Higgs vacuum metastability in primordial inflation, preheating, and reheating

    Science.gov (United States)

    Kohri, Kazunori; Matsui, Hiroki

    2016-11-01

    Current measurements of the Higgs boson mass and top Yukawa coupling suggest that the effective Higgs potential develops an instability below the Planck scale. If the energy scale of inflation is as high as the grand unified theory (GUT) scale, inflationary quantum fluctuations of the Higgs field can easily destabilize the standard electroweak vacuum and produce a lot of anti-de Sitter (AdS) domains. This destabilization during inflation can be avoided if a relatively large nonminimal Higgs-gravity or inflaton-Higgs coupling is introduced. Such couplings generate a large effective mass term for the Higgs, which can raise the effective Higgs potential and suppress the vacuum fluctuation of the Higgs field. After primordial inflation, however, such effective masses drops rapidly and the nonminimal Higgs-gravity or inflaton-Higgs coupling can cause large fluctuations of the Higgs field to be generated via parametric resonance, thus producing AdS domains in the preheating stage. Furthermore, thermal fluctuations of the Higgs field cannot be neglected in the proceeding reheating epoch. We discuss the Higgs vacuum fluctuations during inflation, preheating, and reheating, and show that the Higgs metastability problem is severe unless the energy scale of the inflaton potential is much lower than the GUT scale.

  16. Corrosion leaking of preheater weldment in alumina factories

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li; CHEN Wen-mi; GONG Zhu-qing; LIU Hong-zhao

    2005-01-01

    Stress corrosion cracking (SCC) and anticorrosion measures of TU42C weld-joint were studied by constant load experiments and pickling experiments. The results show that in 40%(mass fraction) NaOH solution at 110 ℃, caustic SCC occurs in TU42C weld-joints at the applied potential of -1 020 mV(vs SCE) for 3 d while at the potential of -950 mV(vs SCE) for 10 d. All the cracks are intergranular. In the 10% sulfuric acid, the cracks have the most negative self-corrosion potential -432.5 mV(vs SCE) and are active to be further corroded by the acid. Because of the same corrosion behaviour as the lab weldment, preheater's cracking in alumina factories is attributed to the combining actions of previous caustic SCC in Bayer solutions and continuous acid corrosion by pickling with the addition of RD. The following measures are effective to prevent the corrosion failure of preheater, such as postweld heat treatment at 620 ℃ to relax the residual weld stress, addition of CC3 and L826 as the corrosion inhibitors to improve the pickling and cleaning by the high pressure water instead of by pickling.

  17. Production of biohydrogen from hydrolyzed bagasse with thermally preheated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Chairattanamanokorn, Prapaipid [Environmental Technology Unit, Department of Environmental Science, Kasetsart University, Bangkok (Thailand); Research Group for Development of Microbial Hydrogen Production Process from Biomass (Thailand); Penthamkeerati, Patthra [Environmental Technology Unit, Department of Environmental Science, Kasetsart University, Bangkok (Thailand); Reungsang, Alissara [Research Group for Development of Microbial Hydrogen Production Process from Biomass (Thailand); Department of Biotechnology, Khon Kaen University, Khon Kaen, Bangkok (Thailand); Lo, Yung-Chung [Department of Chemical Engineering, National Cheng Kung University, Tainan (China); Lu, Wei-Bin [Department of Cosmetic Science, Chung Hwa University of Medical Technology, Tainan (China); Chang, Jo-Shu [Department of Chemical Engineering, National Cheng Kung University, Tainan (China); Sustainable Environment Research Center, National Cheng Kung University, Tainan (China)

    2009-09-15

    Production of biohydrogen from dark fermentation is an interesting alternative to producing renewable fuels because of its low cost and various usable substrates. Cellulosic content in plentiful bagasse residue is an economically feasible feedstock for biohydrogen production. A statistical experimental design was applied to identify the optimal condition for biohydrogen production from enzymatically hydrolyzed bagasse with 60-min preheated seed sludge. The bagasse substrate was first heated at 100 C for 2 h and was then hydrolyzed with cellulase. Culture of the pretreated bagasse at 55 C provided a higher H{sub 2} production performance than that obtained from cultures at 45 C, 65 C, 35 C and 25 C. On the other hand, the culture at pH 5 resulted in higher H{sub 2} production than the cultures at pH 6, pH 4 and pH 7. The optimal culture condition for the hydrogen production rate was around 56.5 C and pH 5.2, which was identified using response surface methodology. Moreover, the pretreatment of bagasse under alkaline conditions gave a thirteen-fold increase in H{sub 2} production yield when compared with that from preheatment under neutral condition. (author)

  18. Effect of preheating on the film thickness of contemporary composite restorative materials

    Directory of Open Access Journals (Sweden)

    Dimitrios Dionysopoulos

    2014-12-01

    Conclusion: The film thickness of the composites tested is material dependent. The thickness of the preheated conventional composites is significantly lower than those at room temperature. The conventional composites provide film thickness values greater than those of the flowable composites regardless of preheating temperature.

  19. Improved design and operation of crude furnace air preheater for cold climates

    Energy Technology Data Exchange (ETDEWEB)

    Gollpudi, B. [Bantrel Co. (Canada); Nichols, D. [Husky Energy (Canada)

    2011-07-01

    In the heavy oil industry, air preheaters are used to heat combustion air with hot flue gas. Flue gas contains significant amounts of sulphur oxides which can result in acid dew point corrosion on the flue gas side. The air preheater metal has therefore to be kept at a temperature higher than this dew point to provide trouble free operation. This paper relates a case of dew point corrosion damage in an air preheater and the design modifications made to solve the problem. The case studied took place at the crude furnace at Husky Energy's Lloydminster Upgrader where a plate exchanger air preheater was installed in 2007 and corrosion was noticed in 2009. It was found that hot air recirculation helps in maintaining a sufficiently high temperature and that the ducting design avoids dead zones. This paper showed that improved design can help to prevent damage occurring in the air preheater.

  20. Molten salt parabolic trough system with synthetic oil preheating

    Science.gov (United States)

    Yuasa, Minoru; Hino, Koichi

    2017-06-01

    Molten salt parabolic trough system (MSPT), which can heat the heat transfer fluid (HTF) to 550 °C has a better performance than a synthetic oil parabolic trough system (SOPT), which can heat the HTF to 400 °C or less. The utilization of HTF at higher temperature in the parabolic trough system is able to realize the design of a smaller size of storage tank and higher heat to electricity conversion efficiency. However, with MSPT there is a great amount of heat loss at night so it is necessary to circulate the HTF at a high temperature of about 290 °C in order to prevent solidification. A new MSPT concept with SOPT preheating (MSSOPT) has been developed to reduce the heat loss at night. In this paper, the MSSOPT system, its performance by steady state analysis and annual performance analysis are introduced.

  1. Frustration of resonant preheating by exotic kinetic terms

    Energy Technology Data Exchange (ETDEWEB)

    Rahmati, Shohreh; Seahra, Sanjeev S., E-mail: srahmati@unb.ca, E-mail: sseahra@unb.ca [Department of Mathematics and Statistics, University of New Brunswick, Fredericton, NB, E3B 5A3 Canada (Canada)

    2014-10-01

    We study the effects of exotic kinetic terms on parametric resonance during the preheating epoch of the early universe. Specifically, we consider modifications to the action of ordinary matter fields motivated by generalized uncertainty principles, polymer quantization, as well as Dirac-Born-Infeld and k-essence models. To leading order in an ''exotic physics'' scale, the equations of motion derived from each of these models have the same algebraic form involving a nonlinear self-interaction in the matter sector. Neglecting spatial dependence, we show that the nonlinearity effectively shuts down the parametric resonance after a finite time period. We find numeric evidence that the frustration of parametric resonance persists to spatially inhomogenous matter in (1+1)-dimensions.

  2. 20 YEARS OF EXPERIENCE WITH SCRAP PREHEATING TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Je. Apfel

    2015-01-01

    Full Text Available More and more countries worldwide implement new rules and regulations to improve energy efficiency and cut CO2 and hazardous off-gas emissions. Thus electric steelmakers need technology that keeps costs low, increases productivity and helps them adhere to environmental regulations. Decades of knowledge in preheating technology, and several different innovative applications which had been solution for many unique cases have been brought together and announced in 2010. EAF Quantum was designed as a pragmatic solution that meets requirements for high energy and cost efficiency, increased productivity and lowest emissions. Whether scrap, partly hot metal or direct-reduced iron (DRI is charged, EAF Quantum is the solution for highly productive electric steelmaking at extra low conversion costs.

  3. Investigation of Preheat Temprature Effect on the Sturcture of Functionally Graded Ni3Al/NiAl/NiTi Intermetallic Compound

    Directory of Open Access Journals (Sweden)

    Musa Kılıç

    2015-12-01

    Full Text Available In this study, a functional graded material (FGM consisted of NiTi NiAl and Ni3Al were manufactured by self-propagating high-temperature synthesis (SHS technique. These three different compound powders were mixed in a rotating container after accurately weighed and cold compacted under 200 MPa pressure. These pressed samples were produced for 200, 300 and 400 ° C preheating temperature by igniting with high voltage under argon gas atmosphere. The microstructures of these functional graded materials were examined by microscopy, Scanning Electron Microscopy (SEM and X-Ray Diffraction (XRD. Consequently, functional graded material successful generated by SHS in every three preheating temperature and the metallic desired compounds were obtained but, it was seen that apart from the main phases in the intersection there are other phases with more melting and gaps.

  4. Primordial black hole production during preheating in a chaotic inflationary model

    CERN Document Server

    Torres-Lomas, E

    2013-01-01

    In this paper we review the production of primordial black holes (PBHs) during preheating after a chaotic inflationary model. All relevant equations of motion are solved numerically in a modified version of HLattice, and we then calculate the mass variance to determine structure formation during preheating. It is found that production of PBHs can be a generic result of the model, even though the results seem to be sensitive to the values of the smoothing scale. We consider a constraint for overproduction of PBHs that could uncover some stress between inflation-preheating models and observations.

  5. Experimental study on preheated combustion of pulverized semi-coke

    Science.gov (United States)

    Yao, Yao; Zhu, Jianguo; Lu, Qinggang; Zhou, Zuxu

    2015-06-01

    In a test rig, pulverized semi-coke was preheated to 850oC in a circulating fluidized bed (CFB) and then combusted at 1100oC in a down-fired combustor (DFC). Experiments were conducted to reveal the effects of three secondary air nozzle cases (co-axial jet, top circular jet and wall circular jet) on the NO emission. The results show that the optimized secondary air nozzle can reduce NO emission. O2 concentration profile is the major factor affecting NO generation and emission, which is led by the secondary air nozzle. The lower O2 concentration led to the generation of lower initial NO. The NO emission at the exit of the DFC was reduced from 189 to 92 mg/m3 (@ 6% O2) with the decrease of initial generation. The peak of NO at 100 mm below the nozzle should be attributed to the oxidization of NH3 in the syngas, rather than the oxidization of fuel-N in the char. The low and well-distributed O2 concentration contributes to the reduction of initial NO, which helps to reduce the NO emission. The combustion efficiencies of the cases of the co-axial jet, the top circular jet, and the wall circular jet are 97.88%, 98.94% and 98.74%, respectively.

  6. Preheating after multifield inflation with nonminimal couplings, II: Resonance Structure

    CERN Document Server

    DeCross, Matthew P; Prabhu, Anirudh; Prescod-Weinstein, Chanda; Sfakianakis, Evangelos I

    2016-01-01

    This is the second in a series of papers on preheating in inflationary models comprised of multiple scalar fields coupled nonminimally to gravity. In this paper, we work in the rigid-spacetime approximation and consider field trajectories within the single-field attractor, which is a generic feature of these models. We construct the Floquet charts to find regions of parameter space in which particle production is efficient for both the adiabatic and isocurvature modes, and analyze the resonance structure using analytic and semi-analytic techniques. Particle production in the adiabatic direction is characterized by the existence of an asymptotic scaling solution at large values of the nonminimal couplings, $\\xi_I \\gg 1$, in which the dominant instability band arises in the long-wavelength limit, for comoving wavenumbers $k \\rightarrow 0$. However, the large-$\\xi_I$ regime is not reached until $\\xi_I \\geq {\\cal O} (100)$. In the intermediate regime, with $\\xi_I \\sim {\\cal O}(10)$, the resonance structure depend...

  7. Experimental Investigation of Flow Resistance in a Coal Mine Ventilation Air Methane Preheated Catalytic Oxidation Reactor

    Directory of Open Access Journals (Sweden)

    Bin Zheng

    2015-01-01

    Full Text Available This paper reports the results of experimental investigation of flow resistance in a coal mine ventilation air methane preheated catalytic oxidation reactor. The experimental system was installed at the Energy Research Institute of Shandong University of Technology. The system has been used to investigate the effects of flow rate (200 Nm3/h to 1000 Nm3/h and catalytic oxidation bed average temperature (20°C to 560°C within the preheated catalytic oxidation reactor. The pressure drop and resistance proportion of catalytic oxidation bed, the heat exchanger preheating section, and the heat exchanger flue gas section were measured. In addition, based on a large number of experimental data, the empirical equations of flow resistance are obtained by the least square method. It can also be used in deriving much needed data for preheated catalytic oxidation designs when employed in industry.

  8. Adaptive preheating duration control for low-power ambient air quality sensor networks.

    Science.gov (United States)

    Baek, Yoonchul; Atiq, Mahin K; Kim, Hyung Seok

    2014-03-20

    Ceramic gas sensors used for measuring ambient air quality have features suitable for practical applications such as healthcare and air quality management, but have a major drawback-large power consumption to preheat the sensor for accurate measurements. In this paper; the adaptive preheating duration control (APC) method is proposed to reduce the power consumption of ambient air quality sensor networks. APC reduces the duration of unnecessary preheating, thereby alleviating power consumption. Furthermore, the APC can allow systems to meet user requirements such as accuracy and periodicity factor when detecting the concentration of a target gas. A performance evaluation of the power consumption of gas sensors is conducted with various user requirements and factors that affect the preheating duration of the gas sensor. This shows that the power consumption of the APC is lower than that of continuous power supply methods and constant power supply/cutoff methods.

  9. Adaptive Preheating Duration Control for Low-Power Ambient Air Quality Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yoonchul Baek

    2014-03-01

    Full Text Available Ceramic gas sensors used for measuring ambient air quality have features suitable for practical applications such as healthcare and air quality management, but have a major drawback—large power consumption to preheat the sensor for accurate measurements. In this paper; the adaptive preheating duration control (APC method is proposed to reduce the power consumption of ambient air quality sensor networks. APC reduces the duration of unnecessary preheating, thereby alleviating power consumption. Furthermore, the APC can allow systems to meet user requirements such as accuracy and periodicity factor when detecting the concentration of a target gas. A performance evaluation of the power consumption of gas sensors is conducted with various user requirements and factors that affect the preheating duration of the gas sensor. This shows that the power consumption of the APC is lower than that of continuous power supply methods and constant power supply/cutoff methods.

  10. Prediction and mitigation of air preheater fouling due to ammonium bisulfate

    Energy Technology Data Exchange (ETDEWEB)

    Afonso, R.; Tavoulareas, S.; Stallings, J. [Energy and Environmental Strategies, MA (United States)

    2001-07-01

    This paper provides a brief review of the fundamentals of ammonium bisulfate (ABS) formation, deposition and fouling in the air preheater. It presents a software-based predictive model for assessing the potential for air preheater fouling as a result of proposed SNCR or SCR retrofits and considering site-specific conditions and introduces a software-based cost-benefit model for assessing the economic trade-offs of various ABS fouling mitigation options. 7 refs., 13 figs.

  11. Stellar and HI Mass Functions Predicted by a Simple Preheating Galaxy Formation Model

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    According to the new preheating mechanism of galaxy formation suggested by Mo et al., we construct a simple model of formation of disk galaxies within the current paradigm of galaxy formation. It incorporates preheating, gas cooling, bulge formation and star formation. The predicted stellar and HI mass functions of galaxies are discussed and compared with the observations. It is found that our model can roughly match both the observed galaxy luminosity function and the observed HI-mass function.

  12. Narrow linewidth pulsed optical parametric oscillator

    Indian Academy of Sciences (India)

    S Das

    2010-11-01

    Tunable narrow linewidth radiation by optical parametric oscillation has many applications, particularly in spectroscopic investigation. In this paper, different techniques such as injection seeding, use of spectral selecting element like grating, grating and etalon in combination, grazing angle of incidence, entangled cavity configuration and type-II phase matching have been discussed for generating tunable narrow linewidth radiation by singly resonant optical parametric oscillation process.

  13. Combustion and Vibration Analysis of Idi- Diesel Engine Fuelled With Neat Preheated Jatropha Methyl Ester

    Directory of Open Access Journals (Sweden)

    Y.Ashok Kumar Reddy

    2014-03-01

    Full Text Available Experimentation is conducted on an IDI diesel engine and the results of combustion and vibration on IDI -Diesel engine fueled with the preheated Jatropha Methyl Ester (JME are presented. The Present research trend is to replace conventional diesel by renewable alternative fuels in view of fast depletion of petroleum reserves and to reduce the exhaust emissions from the engines without altering the basic design of the engine. Due to moderately higher viscosity effects, the direct use of biodiesel in C.I. engines is limited to 20% and the limitation is based on the NO emission also. In this work, the biodiesel is preheated using on line electronically controlled electrical preheating system before it enters into the injector. Experiments are conducted on a four stroke single cylinder IDI engine to find combustion and vibration characteristics of the engine with the preheated Jatropha Methyl Ester (JME heated to temperatures viz. 60,70,80,90 and 1000C. Normally thin oils due to heating may trigger fast burning leading to either detonation or knocking of the engine. This can be predicted by recording vibration on the cylinder head in different directions. The cylinder vibrations in the form of FFT and time waves have been analyzed to estimate the combustion propensity. Experiments are done using diesel, biodiesel and biodiesel at different preheated temperatures and for different engine loading conditions keeping the speed constant at 1500 rpm. Biodiesel preheated to 600C proved encouraging in all respects.

  14. Low-energy electron irradiation of preheated and gas-exposed single-wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Ecton, P.A. [Department of Physics, University of North Texas, Denton, TX 76203 (United States); Beatty, J.; Verbeck, G. [Department of Chemistry, University of North Texas, Denton, TX 76203 (United States); Lakshantha, W.; Rout, B. [Department of Physics, University of North Texas, Denton, TX 76203 (United States); Perez, J.M., E-mail: jperez@unt.edu [Department of Physics, University of North Texas, Denton, TX 76203 (United States)

    2016-11-30

    Highlights: • Preheating SWCNTs in situ before irradiation prevents an increase in the D peak. • Preheated SWCNTs exposed to air or gases before irradiation show an increase in D peak. • The increase in D peak is not due to irradiation-induced chemisorption of adsorbates. • The effects are more significant for small diameter SWCNTs. • The increase in D peak is attributed to defects that increase inter-tube interactions. - Abstract: We investigate the conditions under which electron irradiation at 2 keV of single-wall carbon nanotube (SWCNT) bundles produces an increase in the Raman D peak. We find that irradiation of SWCNTs that are preheated in situ at 600 °C for 1 h in ultrahigh vacuum before irradiation does not result in an increase in the D peak. Irradiation of SWCNTs that are preheated in vacuum and then exposed to air or gases results in an increase in the D peak, suggesting that adsorbates play a role in the increase in the D peak. Small diameter SWCNTs that are not preheated or preheated and then exposed to air show a significant increase in the D and G bands after irradiation. X-ray photoelectron spectroscopy shows no chemical shifts in the C 1s peak of SWCNTs that have been irradiated versus SWCNTs that have not been irradiated, suggesting that chemisorption of adsorbates is not responsible for the increase in the D peak.

  15. Cosmological Simulations of the Preheating Scenario for Galaxy Cluster Formation: Comparison to Analytic Models and Observations

    CERN Document Server

    Younger, Joshua D

    2007-01-01

    We perform a set of non--radiative cosmological simulations of a preheated intracluster medium in which the entropy of the gas was uniformly boosted at high redshift. The results of these simulations are used first to test the current analytic techniques of preheating via entropy input in the smooth accretion limit. When the unmodified profile is taken directly from simulations, we find that this model is in excellent agreement with the results of our simulations. This suggests that preheated efficiently smoothes the accreted gas, and therefore a shift in the unmodified profile is a good approximation even with a realistic accretion history. When we examine the simulation results in detail, we do not find strong evidence for entropy amplification, at least for the high-redshift preheating model adopted here. In the second section of the paper, we compare the results of the preheating simulations to recent observations. We show -- in agreement with previous work -- that for a reasonable amount of preheating, a...

  16. Microwave pre-heating of natural rubber using a rectangular wave guide (MODE: TE10

    Directory of Open Access Journals (Sweden)

    Doo-ngam, N.

    2007-11-01

    Full Text Available This paper presents an application of microwave radiation for pre-heating of natural rubbercompounding with various sulphur contents. The natural rubber-compounding was pre-heated by microwave radiation using a rectangular wave guide system (MODE: TE10 operating at frequency of 2.45 GHz in which the power can vary from 0 to 1500 W. In the present work, the influence of power input, sample thickness, and sulphur content were examined after applying microwave radiation to the rubber samples. Results are discussed regarding the thermal properties, 3-D network, dielectric properties and chemical structures. From the result, firstly, it was found that microwave radiation can be applied to pre-heating natural rubber-compounding before the vulcanization process. Secondly, microwave radiation was very useful for pre-heating natural rubber-compounding that has a thickness greater than 5mm. Thirdly, crosslinking in natural rubber-compounding may occurs after pre-heating by microwave radiation though Fourier Transform Infrared Spectroscopy(FTIR. Finally, there a little effect of sulphur content on temperature profiles after applying microwave radiation to the natural rubber-compounding. Moreover, natural rubber-compounding without carbon black showed a lower heat absorption compared with natural rubbercompounding filled carbon black. This is due to the difference in dielectric loss factor. This preliminary result will be useful information in terms of microwave radiation for pre-heating natural rubber-compounding and rubber processing in industry.

  17. Jihadism, Narrow and Wide

    DEFF Research Database (Denmark)

    Sedgwick, Mark

    2015-01-01

    The term “jihadism” is popular, but difficult. It has narrow senses, which are generally valuable, and wide senses, which may be misleading. This article looks at the derivation and use of “jihadism” and of related terms, at definitions provided by a number of leading scholars, and at media usage....... It distinguishes two main groups of scholarly definitions, some careful and narrow, and some appearing to match loose media usage. However, it shows that even these scholarly definitions actually make important distinctions between jihadism and associated political and theological ideology. The article closes...

  18. Order-disorder type of charge-ordering phase transition in narrow-bandwidth compound, {alpha}'-(BEDT-TTF){sub 2}IBr{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Y.; Yamamoto, K.; Nakano, C.; Uruichi, M. [Institute for Molecular Science and Graduate University for Advanced Studies, Myodaiji, Okazaki, Aichi 444-8585 (Japan); Yakushi, K., E-mail: yakushi@ims.ac.j [Institute for Molecular Science and Graduate University for Advanced Studies, Myodaiji, Okazaki, Aichi 444-8585 (Japan); Inokuchi, M. [Faculty of Science and Engineering, Tokyo University of Science Yamaguchi, 1-1-1 Daigaku-dori, Onoda, Yamaguchi 756-0884 (Japan); Hiejima, T. [Department of Nanochemistry, Tokyo Polytechnic University, 1583 Iiyama, Atsugi, Kanagawa 243-0297 (Japan); Kawamoto, A. [Department of Physics, Hokkaido University, Kita-ku, Sapporo 060-0810 (Japan)

    2010-06-01

    The kinetic energy of {alpha}'-(BEDT-TTF){sub 2}IBr{sub 2}, {alpha}-(BEDT-TTF){sub 2}I{sub 3}, and {alpha}-(BEDT-TTF){sub 2}NH{sub 4}Hg(SCN){sub 4} was estimated from the room-temperature optical conductivity measured from 50 to 30 000 cm{sup -1}. The kinetic energy of {alpha}'-(BEDT-TTF){sub 2}IBr{sub 2} was significantly smaller than that of {alpha}-(BEDT-TTF){sub 2}I{sub 3} that shows metal-insulator phase transition. A clear hysteresis was found in the magnetic susceptibility near the phase transition at around 30 K.

  19. Correlates of Narrow Bracketing

    DEFF Research Database (Denmark)

    Koch, Alexander; Nafziger, Julia

    We examine whether different phenomena of narrow bracketing can be traced back to some common characteristic and whether and how different phenomena are related. We find that making dominated lottery choices or ignoring the endowment when making risky choices are related phenomena and are both as...

  20. Corrosion on air preheaters and economisers; Korrosion hos luftfoervaermare och ekonomisrar

    Energy Technology Data Exchange (ETDEWEB)

    Nordling, Magnus

    2012-05-15

    Combustion plants in Sweden are exposed to considerable stress regarding low temperature corrosion, and failures due to low temperature corrosion occur regularly. Particularly common is corrosion problems connected to air preheaters and economisers. The number of combustion plants having air preheaters and economisers is however large, and the result of a collection of experiences regarding corrosion on air preheaters and economisers therefore has the potential to give a broad knowledge base. The summary of collection of experiences that has been done here, complemented with a literature survey, is expected to give plant owners and plant constructors a valuable tool to prevent corrosion on the flue gas side of air preheaters and economisers. The choice of plants for the inquiry was made using a list from the Swedish Naturvaardsverket (Environmental Protection Agency) indicating the emissions of NO{sub x}gases from Swedish combustion plants. From that list mainly the plants with the largest emissions were chosen, resulting in a number of 30 plants. Depending on that most of the plants have several boilers, and that the connected tubes often have several economisers and air preheaters, the number of economisers and air preheaters in this experience collection is at least 85. The study was however not limited to economisers and air preheaters, but also experiences connected to corrosion of other units were collected when mentioned, and the most interesting information here is also included in the report. Also a number of the plants were visited to improve the basis of the report, e.g. by photographing the most interesting parts. As the insight of the extension of the problem increased, renewed interview rounds were made, and the last one was made in August 2011.

  1. Flexural Strength of Preheated Resin Composites and Bonding Properties to Glass-Ceramic and Dentin

    Directory of Open Access Journals (Sweden)

    Matthias Richard Kramer

    2016-01-01

    Full Text Available To test the impact of preheating (25, 37, 54, or 68 °C of TetricEvoCeram (TEC, FiltekSupremeXT (FSXT, and Venus (V on flexural strength (FS, shear bond strength (SBS and interfacial tension (IFT. FS was tested with TEC and FSXT. For SBS, glass-ceramic and human dentin substrate were fabricated and luted with the preheated resin composite (RC. SBSs of 1500 thermal cycled specimens were measured. For IFT, glass slides covered with the non-polymerized RC were prepared and contact angles were measured. Data were analyzed using 2/1-way ANOVA with Scheffé-test, and t-test (p < 0.05. Preheated TEC (37–68 °C showed higher FS compared to the control-group (25 °C (p < 0.001. FSXT presented higher FS than TEC (p < 0.001. For SBS to dentin higher values for FSXT than TEC were found. The preheating temperature showed no impact on SBS to dentin. SBS to glass-ceramic revealed a positive influence of temperature for TEC 25–68 °C (p = 0.015. TEC showed higher values than V and FSXT (p < 0.001. IFT values increased with the preheating temperature. A significant difference could be observed in every RC group between 25 and 68 °C (p < 0.001.

  2. Effect of preheating on the viscoelastic properties of dental composite under different deformation conditions.

    Science.gov (United States)

    Ahn, Kyung Hyun; Lim, Sanghyuk; Kum, Kee Yeon; Chang, Seok Woo

    2015-01-01

    Preheating of dental composites improves their flowability, facilitating successful restorations. However, the flowability of dental composites is affected not only by temperature but also by the deformation conditions. In the present work, the effects of various deformation conditions upon the viscoelastic properties of a preheated dental composite were studied. The rheological properties of Z350 dental composites at 25, 45, and 60°C were measured by a strain-controlled rheometer. When a low strain (0.03%) was applied, the preheated composite exhibited greater shear storage modulus (G') and complex viscosity (η*) than a room-temperature composite. Oppositely, when a high strain (50%) was applied, G' and η* of a preheated composite were lower than those of a room-temperature composite. Preheating of dental composites might be helpful in clinical practice both to increase the slumping resistance when minimal manipulation is used (e.g., during the build-up of a missing cusp tip) and to increase flowability when manipulation entailing high shear strain is applied (e.g., when uncured composite resin is spread on a dentin surface).

  3. Effect of pre-heating on the viscosity and microhardness of a resin composite.

    LENUS (Irish Health Repository)

    Lucey, S

    2010-04-01

    The effect of pre-heating resin composite on pre-cured viscosity and post-cured surface hardness was evaluated. Groups of uncured specimens were heated to 60 degrees C and compared with control groups (24 degrees C) with respect to viscosity and surface hardness. Mean (SD) viscosities of the pre-heated specimens (n = 15) were in the range of 285 (13)-377 (11) (Pa) compared with 642 (35)-800 (23) (Pa) at ambient temperature. There was a statistically significant difference between the two groups (P < 0.001). Mean (SD) Vickers microhardness (VHN) of the pre-heated group (n = 15) was 68.6 (2.3) for the top surface and 68.7 (1.8) for the bottom surface measured at 24 h post curing (specimen thickness = 1.5 mm). The corresponding values for the room temperature group were 60.6 (1.4) and 59.0 (3.5). There was a statistically significant difference between corresponding measurements taken at the top and bottom for the pre-heated and room temperature groups (P < 0.001). There was no significant difference between top and bottom measurements within each group. Pre-heating resin composite reduces its pre-cured viscosity and enhances its subsequent surface hardness. These effects may translate as easier placement together with an increased degree of polymerization and depth-of-cure.

  4. Numerical Simulation of Jet Behavior and Impingement Characteristics of Preheating Shrouded Supersonic Jets

    Institute of Scientific and Technical Information of China (English)

    Guang-sheng WEI; Rong ZHU; Ting CHENG; Fei ZHAO

    2016-01-01

    As a novel supersonic j et technology,preheating shrouded supersonic j et was developed to deliver oxygen into molten bath efficiently and affordably.However,there has been limited research on the jet behavior and im-pingement characteristics of preheating shrouded supersonic j ets.Computational fluid dynamics (CFD)models were established to investigate the effects of main and shrouding gas temperatures on the characteristics of flow field and impingement of shrouded supersonic j et.The preheating shrouded supersonic j et behavior was simulated and meas-ured by numerical simulation and j et measurement experiment respectively.The influence of preheating shrouded su-personic j et on gas j et penetration and fluid flow in liquid bath was calculated by the CFD model which was validated against water model experiments.The results show that the uptrend of the potential core length of shrouded super-sonic j et would be accelerated with increasing the main and shrouding gas temperatures.Also,preheating supersonic j ets demonstrated significant advantages in penetrating and stirring the liquid bath.

  5. SRC-II slurry preheater technical uncertainties. Report for the technical data analysis program

    Energy Technology Data Exchange (ETDEWEB)

    1984-06-01

    This report reviews the performance, and draws conclusions therefrom, the coal slurry preheaters of the Ft. Lewis, Washington, Solvent Refined Coal (SRC) Pilot Plant in the following areas: Coking, Erosion Corrosion, Heat transfer and pressure drop effects. Using prudent engineering judgement it postulates how such conclusions should affect the design and operability of large preheaters in future commercial scale plants. Also a recommendation is made for a small scale research and development effort that should result in a much firmer preheater design for any future facility. This report should be read in conjunction with the Solvent Refined Coal (SRC) Final Report, and volumes 1 and 2 of Slurry Preheater Design, SRC-II Process and also Ft. Lewis Slurry Preheater Data Analysis, 1-1/2 Inch Coil by Gulf Science and Technology Company of Pittsburgh, Pennsylvania. The Pittsburg and Midway Coal Mining Co.'s background is based primarily on a racetrack shaped up-flow coil and these comments pertain specifically to a commercial heater of that type of design. 5 references, 12 figures, 1 table.

  6. Effect of pre-heating on the mechanical properties of silorane-based and methacrylate-based composites

    Science.gov (United States)

    Mohammadi, Narmin; Jafari-Navimipour, Elmira; Kimyai, Soodabeh; Ajami, Amir-Ahmad; Bahari, Mahmoud; Ansarin, Mohammad

    2016-01-01

    Background The use of composites in dental restoration has been commonly criticized, due to their underwhelming mechanical properties. This problem may be solved partially by preheating. The present research aims to determine the effect of preheating on the mechanical properties of two different classes of composites. Material and Methods A Silorane-based (Silorane) and a Methacrylate-based (Z250) composite were preheated to different temperatures (25, 37, and 68 °C) and afterwards were tested with the appropriate devices for each testing protocol. The material’s flexural strength, elastic modulus, and Vickers microhardness were evaluated. Two-way ANOVA, and Tukey’s post hoc were used to analyze the data. Results Microhardness and elastic modulus increased with preheating, while flexural strength values did not increase significantly with preheating. Furthermore the methacrylate-based composite (Z250) showed higher values compared to the Silorane-based composite (Silorane) in all the tested properties. Conclusions Preheating Silorane enhances the composite’s microhardness and elastic modulus but does not affect its flexural strength. On the other hand, preheating Z250 increases its microhardness but does not change its flexural strength or elastic modulus. In addition, the Z250 composite shows higher microhardness and flexural strength than Silorane, but the elastic modulus values with preheating are similar. Therefore Z250 seems to have better mechanical properties making it the better choice in a clinical situation. Key words:Composite, elastic modulus, flexural strength, microhardness, preheating. PMID:27703604

  7. Microlayer during boiling in narrow slot channels

    Science.gov (United States)

    Diev, Mikhail D.; Leontiev, Alexander I.

    1997-01-01

    An international space station Alpha will have a two-phase thermal control system. Boiling of a liquid ammonia will be a process of heat collection in evaporative heat exchangers. Unfortunately, only little data is available for boiling heat transfer in microgravity. Geometries of boiling channels working good in normal gravity are not appropriate in microgravity, and special means should be worked out to avoid some undesired events. From this point of view, the narrow slot channels may be assumed as a promising geometry for microgravity operation. During boiling in narrow slots, the vapor bubbles are flattened between the channel walls. The vapor phase and the channel wall are separated by a thin liquid film which is known as a microlayer. The paper presents the experimental results compared to the theoretical analysis, the paper also shows the narrow slot channels as a perspective configuration for microgravity applications.

  8. Performance Evaluation of Diesel Engine with Preheated Bio Diesel with Additives

    Science.gov (United States)

    Ram Vajja, Sai; Murali, R. B. V.

    2016-09-01

    This paper mainly reviews about the usage of preheated bio diesel added with 0.5% Etchant as an alternative fuel and evaluates its performance for various blends with different loads. Bio diesel is added with Etchant for rapid combustion as for the bio diesel, the cetane number is high that results in shorter delay of ignition and the mixture is preheated to raise its temperature to improve the combustion process. Analysis of the parameters required to define the combustion characteristics such as IP, BP, ηbth, ηm, ISFC, BSFC, IMEP, MFC, Exhaust Gas Temperature, Heat Release and heat balance is necessary as these values are significant to assess the performance of engine and its emissions of preheated bio diesel.

  9. Waste heat recovery at the glass industry with the intervention of batch and cullet preheating

    Directory of Open Access Journals (Sweden)

    Dolianitis Ioannis

    2016-01-01

    Full Text Available A promising option to reduce the specific energy consumption and CO2 emissions at a conventional natural gas fired container glass furnace deals with the advanced utilization of the exhaust gases downstream the air regenerators by means of batch and cullet preheating. A 3-dimensional computational model that simulates this process using mass and heat transfer equations inside a preheater has been developed. A case study for an efficient small-sized container glass furnace is presented dealing with the investigation of the impact of different operating and design configurations on specific energy consumption, CO2 emissions, flue gas energy recovery, batch temperature and preheater efficiency. In specific, the effect of various parameters is studied, including the preheater’s dimensions, flue gas temperature, batch moisture content, glass pull, combustion air excess and cullet fraction. Expected energy savings margin is estimated to 12-15%.

  10. The benefit of solid oxide fuel cells with integrated air pre-heater

    Energy Technology Data Exchange (ETDEWEB)

    Costamagna, P. [Univ. degli Studi di Genova, Fac. di Ingegneria, ISTIC, Inst. di Ingegneria Chimica e di Processo `G.B. Bonino`, Genova (Italy)

    1997-11-01

    A new design has recently been proposed in the field of solid oxide fuel cells, consisting of a traditional electrochemical cell integrated with a pre-heater. In this paper a simulation model for the rectangular planar solid oxide fuel cell with integrated air pre-heater is presented. A two-dimensional stack simulation is presented as well, one axis coincides with the fuel flow direction, the other with the stack height. Local quantities such as current density, gas and solid temperatures are reported and cell characteristics predicted. In a parameter study, effects of oxygen utilisation and heat-transfer conditions in the pre-heater on the local temperature distribution of the solid structure are considered. As a result, the benefit of the new cell design becomes evident when low air flow rates are applied. A further advantage associated with the reduced flow rate is the low air temperature at the inlet. (orig.)

  11. Diagnosing laser-preheated magnetized plasmas relevant to magnetized liner inertial fusion

    Science.gov (United States)

    Harvey-Thompson, A. J.; Sefkow, A. B.; Nagayama, T. N.; Wei, M. S.; Campbell, E. M.; Fiksel, G.; Chang, P.-Y.; Davies, J. R.; Barnak, D. H.; Glebov, V. Y.; Fitzsimmons, P.; Fooks, J.; Blue, B. E.

    2015-12-01

    We present a platform on the OMEGA EP Laser Facility that creates and diagnoses the conditions present during the preheat stage of the MAGnetized Liner Inertial Fusion (MagLIF) concept. Experiments were conducted using 9 kJ of 3ω (355 nm) light to heat an underdense deuterium gas (electron density: 2.5 ×1020 cm-3=0.025 of critical density) magnetized with a 10 T axial field. Results show that the deuterium plasma reached a peak electron temperature of 670 ± 140 eV, diagnosed using streaked spectroscopy of an argon dopant. The results demonstrate that plasmas relevant to the preheat stage of MagLIF can be produced at multiple laser facilities, thereby enabling more rapid progress in understanding magnetized preheat. Results are compared with magneto-radiation-hydrodynamics simulations, and plans for future experiments are described.

  12. Effect of Intermediate Agents and Preheated Composites on Repair Bond Strength of Silorane-Based Composites

    Directory of Open Access Journals (Sweden)

    Fereshteh Shafiei

    2016-05-01

    Full Text Available Objectives: Repairing composite restorations is a challenging procedure especially when two different types of composites are used. This study aimed to compare the repair strength of silorane-based composite (SC (Filtek P90 with that of preheated SC, methacrylate composite (MC(Z250, flowable MC (Filtek Supreme Plus and different adhesive/composite combinations.Materials and Methods: Eighty-four SC specimens were fabricated and randomly divided into seven groups (G. In the control group (G7, SC was bonded immediately to SC. The other specimens were water-aged for two months and were then roughened, etched and repaired with the following materials: G1 Silorane Adhesive Bond (SAB/SC;G2 Preheated SC; G3 SAB/MC; G4 Adper Single Bond (SB/MC; G5 Flowable MC/MC; G6 Preheated MC. After water storage and thermocycling, the repaired specimens were subjected to shear bond strength testing. The data were analyzed using ANOVA and Tukey’s test.Results: Preheated SC and MC, flowable MC and SAB/SC resulted in bond strength comparable to that of the control group. Preheated SC showed significantly higher bond strength when compared to SAB/MC (P=0.04 and SB/MC (P<0.001. Bond strength of SB/MC was significantly lower than that of the other groups (P<0.05, except for SAB/SC and SAB/MC.Conclusion: All repairing materials except for SB/MC resulted in bond strength values comparable to that of the control group. Repair with preheated SC yielded the highest bond strength. 

  13. Effects of Preheated Composite on Micro leakage-An in-vitro Study

    Science.gov (United States)

    Raj, James David; Sherlin, Herald

    2016-01-01

    Introduction Resin composites have been the pinnacle of direct esthetic restorations ever since its discovery. However, it comes with its own disadvantages. Post-operative sensitivity and marginal discoloration frequently occur due to polymerization shrinkage and micro leakage, which is the major cause of failure in resin composite restorations. Aim To evaluate the effects of preheated composite at different temperatures on microleakage. Materials and Methods A total of 60 extracted non-carious human premolars were collected and class 1 cavity (1.5x4x 3mm) was prepared in each and were randomly divided into three groups. Group 1 (n=20) was filled with microhybrid resin composite (Heraeus Charisma Smile) at room temperature. Group 2 (n=20) was filled with the same resin composite which was preheated to 50°C and Group 3 (n=20) was filled with resin composite preheated to 60°C. Teeth were subjected to a thermocycling regime (500X, 5 - 55°C), followed by a dye infiltration by immersing in basic fuschin for 24 hours. The tooth was sectioned longitudinally and the extent or absence of micro-leakage was determined by the amount of dye penetration along the resin composite-tooth interface using a confocal microscope. Results There was minor micro-leakage detected at the occlusal margin of the control tooth specimen. The sample with preheated composite restoration at 50°C showed an intact tooth-restoration interface with no micro leakage. However, the preheated composite at 60°C showed large amount of microleakage. Conclusion Under the current limitation of the study, preheated composite at 50°C showed the least micro-leakage. PMID:27504407

  14. Effect of pre-heating on hardness of methacrylate- and silorane-based composites

    OpenAIRE

    Catelan, Anderson; Barreto,Bruno; Lima, Adriano; Oliveira, Marcelo; Marchi, Giselle; Aguiar, Flávio

    2014-01-01

    AIM: To evaluate the effect of composite pre-heating on the microhardness of different monomer resin-based. MATERIALS AND METHOD: Circular specimens of methacrylate- and silorane-based composite resins pre-heated at 23, 39, and 55˚ C were carried out, and cured using a halogen light-curing unit at 650 mW/cm². After 24 h, the specimens were polished and Knoop hardness number (KHN) was measured using a microhardness tester with 50-g load for 15 s. The data were analyzed with ANOVA and Tukey’s t...

  15. Relation between the occurrence of Burnout and differential pressure fluctuation characteristics caused by the disturbance waves passing by a flow obstacle in a vertical boiling two-phase upward flow in a narrow annular channel

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Shoji [Yokohama National University, Yokohama 240-8501 (Japan)]. E-mail: morisho@ynu.ac.jp; Fukano, Tohru [Kurume Institute of University, Fukuoka 830-0052 (Japan)]. E-mail: fukanot@cc.kurume-it.ac.jp

    2006-05-15

    If a flow obstacle such as a spacer is placed in a boiling two-phase flow within a channel, the temperature on the surface of the heating tube is severely affected by the existence of the spacer. Under certain conditions the spacer has a cooling effect, and under other conditions the spacer causes dryout of the cooling water film on the heating surface, resulting in burnout of the tube. The burnout mechanism near the spacer, however, remains unclear. In a previous paper (Fukano, T., Mori, S., Akamatsu, S., Baba, A., 2002. Relation between temperature fluctuation of a heating surface and generation of drypatch caused by a cylindrical spacer in a vertical boiling two-phase upward flow in a narrow annular channel. Nucl. Eng. Des. 217, 81-90), we reported that the disturbance wave has a significant effect on dryout occurrence. Therefore, in the present paper, the relation between dryout, burnout occurrence, and interval between two successive disturbance waves obtained from the differential pressure fluctuation caused by the disturbance waves passing by a spacer, is further discussed in detail.

  16. Ultra-fast high-efficiency enantioseparations by means of a teicoplanin-based chiral stationary phase made on sub-2 μm totally porous silica particles of narrow size distribution.

    Science.gov (United States)

    Ismail, Omar H; Ciogli, Alessia; Villani, Claudio; De Martino, Michela; Pierini, Marco; Cavazzini, Alberto; Bell, David S; Gasparrini, Francesco

    2016-01-01

    A new ultra-high performance teicoplanin-based stationary phase was prepared starting from sub-2 μm totally porous silica particles of narrow size distribution. Columns of different lengths were packed at high pressure and a deep and systematic evaluation of kinetic performance, in terms of van Deemter analysis, was performed under different elution conditions (HILIC, POM, RP and NP) by using both achiral and chiral probes. For the achiral probes, the efficiency of the columns at the minimum of the van Deemter curves were very high leading to some 278,000, 270,000, 262,000 and 232,000 plates/m in hydrophilic interaction liquid chromatography (HILIC), polar organic mode (POM), normal phase (NP) and reversed phase (RP) respectively. The lowest plate height, Hmin=3.59 μm (h(/)=1.89), was obtained under HILIC conditions at a flow rate of 1.4 mL/min. Efficiency as high as 200,000-250,000 plates/m (at the optimum flow rate) was obtained in the separation of the enantiomers of chiral probes under HILIC/POM conditions. N-protected amino acids, α-aryloxy acids, herbicides, anti-inflammatory agents were baseline separated on short (2-cm) and ultra-short (1-cm) columns, with analysis time in the order of 1 min. The enantiomers of N-BOC-d,l-methionine were successfully baseline separated in only 11s in HILIC mode. Several examples of fast and efficient resolutions in sub/supercritical fluid chromatography were also obtained for a range of chiral carboxylic acids.

  17. Computation with narrow CTCs

    CERN Document Server

    Say, A C Cem

    2011-01-01

    We examine some variants of computation with closed timelike curves (CTCs), where various restrictions are imposed on the memory of the computer, and the information carrying capacity and range of the CTC. We give full characterizations of the classes of languages recognized by polynomial time probabilistic and quantum computers that can send a single classical bit to their own past. Such narrow CTCs are demonstrated to add the power of limited nondeterminism to deterministic computers, and lead to exponential speedup in constant-space probabilistic and quantum computation. We show that, given a time machine with constant negative delay, one can implement CTC-based computations without the need to know about the runtime beforehand.

  18. Low-energy electron irradiation of preheated and gas-exposed single-wall carbon nanotubes

    Science.gov (United States)

    Ecton, P. A.; Beatty, J.; Verbeck, G.; Lakshantha, W.; Rout, B.; Perez, J. M.

    2016-11-01

    We investigate the conditions under which electron irradiation at 2 keV of single-wall carbon nanotube (SWCNT) bundles produces an increase in the Raman D peak. We find that irradiation of SWCNTs that are preheated in situ at 600 °C for 1 h in ultrahigh vacuum before irradiation does not result in an increase in the D peak. Irradiation of SWCNTs that are preheated in vacuum and then exposed to air or gases results in an increase in the D peak, suggesting that adsorbates play a role in the increase in the D peak. Small diameter SWCNTs that are not preheated or preheated and then exposed to air show a significant increase in the D and G bands after irradiation. X-ray photoelectron spectroscopy shows no chemical shifts in the C 1s peak of SWCNTs that have been irradiated versus SWCNTs that have not been irradiated, suggesting that chemisorption of adsorbates is not responsible for the increase in the D peak.

  19. Area 3, SRC-II coal slurry preheater studies report for the technical data analysis program

    Energy Technology Data Exchange (ETDEWEB)

    1984-08-01

    This report reviews the raw data gathered from the Preheater B test runs at Ft. Lewis, and also the Preheater B results presented in the Solvent Refined Coal (SRC) Process Final Report, Volumes 1 and 2 of Slurry Preheater Design, SRC-II Process and the Ft. Lewis Slurry Preheater Data Analysis, 1 1/2 Inch Coil by Gulf Science and Technology Corporation of Pittsburgh, Pennsylvania. attempts were made to correlate several variables not previously considered with slurry viscosity and thermal conductivity. Only partial success was realized. However, in the process of attempting to correlate these variables an understanding of why some variables could not be correlated was achieved. An attempt was also made, using multiple linear regression, to correlate coal slurry viscosity and thermal conductivity with several independent variables among which were temperature, coal concentration, total solids, coal type, slurry residence time, shear rate, and unit size. The final correlations included some, but not all, of these independent variables. This report is not a stand alone document and should be considered a supplement to work already done. It should be read in conjunction with the reports referenced above.

  20. Effect of preheating and light-curing unit on physicochemical properties of a bulk fill composite.

    Science.gov (United States)

    Theobaldo, Jéssica Dias; Aguiar, Flávio Henrique Baggio; Pini, Núbia Inocencya Pavesi; Lima, Débora Alves Nunes Leite; Liporoni, Priscila Christiane Suzy; Catelan, Anderson

    2017-01-01

    The aim of this study is to evaluate the effect of composite preheating and polymerization mode on degree of conversion (DC), microhardness (KHN), plasticization (P), and depth of polymerization (DP) of a bulk fill composite. Forty disc-shaped samples (n = 5) of a bulk fill composite were prepared (5 × 4 mm thick) and randomly divided into 4 groups according to light-curing unit (quartz-tungsten-halogen [QTH] or light-emitting diode [LED]) and preheating temperature (23 or 54 °C). A control group was prepared with a flowable composite at room temperature. DC was determined using a Fourier transform infrared spectrometer, KHN was measured with a Knoop indenter, P was evaluated by percentage reduction of hardness after 24 h of ethanol storage, and DP was obtained by bottom/top ratio. Data were statistically analyzed by analysis of variance and Tukey's test (α = 0.05). Regardless of light-curing, the highest preheating temperature increased DC compared to room temperature on bottom surface. LED showed a higher DC compared to QTH. Overall, DC was higher on top surface than bottom. KHN, P, and DP were not affected by curing mode and temperature, and flowable composite showed similar KHN, and lower DC and P, compared to bulk fill. Composite preheating increased the polymerization degree of 4-mm-increment bulk fill, but it led to a higher plasticization compared to the conventional flowable composite evaluated.

  1. Abstract of a report on reducing resistance in gas-fired preheaters

    Energy Technology Data Exchange (ETDEWEB)

    1939-04-27

    The demands of Hydro-works Scholven to increase the capacity of one of their preheaters, with consequently greater volume of circulating gases, inspired the idea to study the resistance to the flow of gases in the preheaters. The resistance varied with the square of the velocity, so that pressure differences beyond the capacity of the single-stage Schiele blowers could be easily developed. It was intended, therefore, to determine the exact course of the pressure loss in preheaters in operation at Scholven. Since this met with many practical difficulties, it was supplemented by measurements on sheet steel models built to one-tenth their actual size. The measurements on the preheaters already in service showed that the pressure loss in the heating chamber proper, that is the pressure losses applicable to heat transmission, were small compared to the total pressure loss. The greatest proportion of the heating loss occurred in the inlet and outlet ducts and passages. This indicated that particular attention must be paid to the resistance in the ducts and the distributing points. The gas distribution needed to be arranged such that energy-consuming dampers could be eliminated. Where bends could not be avoided, guide vanes could considerably reduce the pressure loss. It was suggested to use an Escher--Weiss axial blower system instead of the Schiele radial blower. Reduction of pressure losses would increase velocity of the gases in the heating flues and thus increase heat transmission in the hairpin coils.

  2. System Performance Measurement Supports Design Recommendations for Solar Ventilation Preheat System (Brochure)

    Energy Technology Data Exchange (ETDEWEB)

    2011-08-01

    Technical briefing to report the outcomes of a data monitoring effort to determine the nature of solar vent preheat system performance problems at a U.S. military installation. The analysis reports up-to-date research and findings regarding system design, helping to clarify the issue as a factor of system design, rather than a shortcoming of SVP systems.

  3. Effect of Preheating in Hybrid Friction Stir Welding of Aluminum Alloy

    Science.gov (United States)

    Yaduwanshi, D. K.; Bag, S.; Pal, S.

    2014-10-01

    The controlled energy input into the system by introducing an extra heat source to enhance the material flow along with reduction of the plunging force remains a potential area of considerate for the development of hybrid friction stir welding (FSW) process. Hence, the effect of preheating on the weld joint properties is evaluated using plasma-assisted friction stir welding (P-FSW) process for joining aluminum alloy. A comparative study of mechanical and macro-microstructural characterizations of weld joint by FSW and P-FSW has been performed. Transverse tensile strength of weld joint is approximately 95% of base metal produced by P-FSW and is 8% more than conventional FSW welds. The effect of preheating enhances material flow and dissolution of fine oxide particles by plasma arc results in increase of strength and marginal modification of deformation behavior. The preheating brings uniformly distributed hardness in weld zone and the magnitude is higher in the advancing side with overall increase in average hardness value. Grain sizes are much finer due to the pinning effect of Al2O3 particles that retarded grain growth following recrystallization during P-FSW and thus led to more pronounced reduction in grain size and relatively brittle fracture during tensile loading of welded joint. Overall, the influence of preheating acts quite homogeneously throughout the structure as compared to conventional FSW. However, the results reveal that the development of P-FSW is still in initial stage and needs to improve in various aspects.

  4. Little evidence for non-gravitational energy feedback beyond $r_{500}$ - An end to ICM preheating?

    CERN Document Server

    Iqbal, Asif; Nath, Biman B; Ettori, Stefano; Eckert, Dominique; Malik, Manzoor A

    2016-01-01

    Non-gravitational feedback affects the nature of the intra-cluster medium (ICM). X-ray cooling of the ICM and in situ energy feedback from AGN's and SNe as well as preheating of the gas at epochs preceding the formation of clusters are proposed mechanisms for such feedback. While cooling and AGN feedbacks are dominant in cluster cores, the signatures of a preheated ICM are expected to be present even at large radii. To estimate the degree of preheating, with minimum confusion from AGN feedback/cooling, we study the non-gravitational feedback energy profiles upto $r_{200}$ for a sample of 17 galaxy clusters using joint data sets of Planck SZ pressure profiles and ROSAT/PSPC gas density profiles. We show that the estimated energy feedback profile of the ICM is consistent with zero at 1$\\sigma$ beyond $\\sim r_{500}$. The canonical value of preheating energy of 1 keV/particle, needed in order to match energy entropy floors and cluster scalings, is ruled out at $4.4\\sigma$ beyond $r_{500}$. Our results take both n...

  5. Preheating to around 100°C under endcap blocks before welding at KHI.

    CERN Multimedia

    Loveless, D

    2000-01-01

    The 600mm thick sector blocks of the CMS endcaps are made from three layers of 200mm plates welded together. During the manufacture at KHI, the blocks are preheated to around 100°C to prevent cracks in the welds.

  6. The Accretion and Cooling of Preheated Gas in Dark Matter Halos

    CERN Document Server

    Lu, Y; Lu, Yu

    2006-01-01

    (abridged) We use a one-dimensional hydrodynamical code to investigate the effects of preheating on gas accretion and cooling in cold dark matter halos. In the absence of radiative cooling, preheating reduces the amount of gas that can be accreted into a halo, and the accreted gas fraction is determined by the ratio of the initial specific entropy of the gas to the virial entropy of the halo. In the presence of radiative cooling, preheating affects the gas fraction that can cool in two different ways. For small halos with masses 10^13Msun. We suggest that this may be the reason why the stellar mass function of galaxies breaks sharply at the massive end. Such preheating also helps create the hot diffused halos within which the "radio mode" feedback of AGNs can act effectively. In the second case, we assume the intergalactic medium is warm. Here the total amount of gas that can cool in a halo scales with halo mass as ~M^2, as would be required to match the observed stellar- and HI-mass functions in the current ...

  7. 摇摆工况下窄矩形通道内两相沸腾摩擦压降特性%Two-phase frictional pressure drop characteristics of boiling flow in rectangular narrow channel under rolling motion

    Institute of Scientific and Technical Information of China (English)

    陈冲; 高璞珍; 余志庭; 陈先兵

    2015-01-01

    In order to investigate the two-phase frictional pressure drop characteristics of boiling flows in a rectangular narrow channel under rolling motion, a series of thermal hydraulic experiments and theoretical analysis are performed. The results demonstrate that the additional inertial force is imposed on the fluid and the space of experimental loop will vary periodically under rolling motion. The fluctuation amplitude of the two-phase frictional gradient increases with increasing rolling angle and rolling period. The fluctuation amplitude and time average value of the two-phase frictional pressure gradient increase with increasing heat flux, while it decreases with the increase of system pressure. The mass flux varies with the fluctuation of frictional pressure gradient at the same period. The phase change between the fluctuation of mass flux and frictional pressure gradient is approximately equal to 1/4 rolling period due to the velocity difference of the pressure propagation and mass flux increases.%为了研究摇摆工况下窄矩形通道内的两相摩擦压降特性,进行了一系列的热工水力实验和理论分析。结果表明,摇摆工况下流体会受到附加惯性力的作用且实验回路的空间位置也会出现周期性的变化,两相摩擦压降梯度的波动振幅随着摇摆角度和摇摆周期的增加而增加;随着通道热通量的增加或者系统压强的减小,两相摩擦压降梯度的波动振幅和时均值逐渐增加。窄矩形通道内的质量流速随着两相摩擦压降梯度的波动而波动,且具有相同的波动周期,由于流体加速和压力传播的速度不同,流量波动和摩擦压降波动存在约1/4周期的相位差。

  8. Narrow, duplicated internal auditory canal

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, T. [Servico de Neurorradiologia, Hospital Garcia de Orta, Avenida Torrado da Silva, 2801-951, Almada (Portugal); Shayestehfar, B. [Department of Radiology, UCLA Oliveview School of Medicine, Los Angeles, California (United States); Lufkin, R. [Department of Radiology, UCLA School of Medicine, Los Angeles, California (United States)

    2003-05-01

    A narrow internal auditory canal (IAC) constitutes a relative contraindication to cochlear implantation because it is associated with aplasia or hypoplasia of the vestibulocochlear nerve or its cochlear branch. We report an unusual case of a narrow, duplicated IAC, divided by a bony septum into a superior relatively large portion and an inferior stenotic portion, in which we could identify only the facial nerve. This case adds support to the association between a narrow IAC and aplasia or hypoplasia of the vestibulocochlear nerve. The normal facial nerve argues against the hypothesis that the narrow IAC is the result of a primary bony defect which inhibits the growth of the vestibulocochlear nerve. (orig.)

  9. A Compact Narrow-Band Tunable Optical Transversal Filter

    Institute of Scientific and Technical Information of China (English)

    Zhigang Wu; Katsuyuki Utaka

    2003-01-01

    We present a compact narrow-band tunable optical transversal filter with phase-variable taps. A transmission bandwidth of the comb filter is less than 0.2nm and can be continuously tuned in the entire FSR.

  10. Effect of Combustion Air Pre-Heating In Carbon Monoxide Emission in Diesel Fired Heat Treatment Furnace

    Directory of Open Access Journals (Sweden)

    E B Muhammed Shafi,

    2015-09-01

    Full Text Available This paper describes the effect of combustion air pre- heating in Diesel fired heat Treatment Furnace. The main heat treatment processes are Normalizing, Tempering, Hardening, Annealing, Solution Annealing and Stress Relieving. The emission of carbon monoxide is measured with combustion air pre-heating and without preheating. The results are then compared and it is found that the emission of CO is reduced by 29.12%. With the Combustion air pre-heating a considerable reduction in Specific Furnace Fuel Consumption (SFFC is obtained. The test was caaried out at Peekay Steels Casting (P ltd, Nallalam, Calicut.

  11. Preheating in an Asymptotically Safe Quantum Field Theory

    CERN Document Server

    Svendsen, Ole; Brandenberger, Robert

    2016-01-01

    We consider reheating in a class of asymptotically safe quantum field theories recently studied in \\cite{Litim:2014uca, Litim:2015iea}. These theories allow for an inflationary phase in the very early universe. Inflation ends with a period of reheating. Since the models contain many scalar fields which are intrinsically coupled to the inflaton there is the possibility of parametric resonance instability in the production of these fields, and the danger that the induced curvature fluctuations will become too large. Here we show that the parametric instability indeed arises, and that hence the energy transfer from the inflaton condensate to fluctuating fields is rapid. Demanding that the curvature fluctuations induced by the parametrically amplified entropy modes do not exceed the upper observational bounds puts a lower bound on the number of fields which the model of Ref.~\\cite{Litim:2014uca, Litim:2015iea} must contain. This bound also depends on the total number of e-foldings of the inflationary phase.

  12. Preheating in an asymptotically safe quantum field theory

    Science.gov (United States)

    Svendsen, Ole; Moghaddam, Hossein Bazrafshan; Brandenberger, Robert

    2016-10-01

    We consider reheating in a class of asymptotically safe quantum field theories recently studied in [D. F. Litim and F. Sannino, Asymptotic safety guaranteed, J. High Energy Phys. 12 (2014) 178; D. F. Litim, M. Mojaza, and F. Sannino, Vacuum stability of asymptotically safe gauge-Yukawa theories, J. High Energy Phys. 01 (2016) 081]. These theories allow for an inflationary phase in the very early universe. Inflation ends with a period of reheating. Since the models contain many scalar fields which are intrinsically coupled to the inflaton there is the possibility of parametric resonance instability in the production of these fields, and the danger that the induced curvature fluctuations will become too large. Here we show that the parametric instability indeed arises, and that hence the energy transfer from the inflaton condensate to fluctuating fields is rapid. Demanding that the curvature fluctuations induced by the parametrically amplified entropy modes do not exceed the upper observational bounds puts a lower bound on the number of fields which the model followed in [D. F. Litim and F. Sannino, Asymptotic safety guaranteed, J. High Energy Phys. 12 (2014) 178; D. F. Litim, M. Mojaza, and F. Sannino, Vacuum stability of asymptotically safe gauge-Yukawa theories, J. High Energy Phys. 01 (2016) 081] must contain. This bound also depends on the total number of e -foldings of the inflationary phase.

  13. Influence of the Previous Preheating Temperature on the Static Coefficient of Friction with Lubrication

    Directory of Open Access Journals (Sweden)

    M. Živković

    2016-12-01

    Full Text Available Experimental investigations static coefficient of friction in lubricated conditions and pre-heating of the sample pin at high temperatures is discussed in this paper. The static coefficient of friction was measured in the sliding steel copper pins per cylinder of polyvinylchloride. Pins are previously heated in a special chamber from room temperature to a temperature of 800 oC with a step of 50 °C. Tribological changes in the surface layer of the pins caused by pre-heating the pins at high temperatures and cooling systems have very significantly influenced the increase in the coefficient of static friction. The results indicate the possibility of improving the friction characteristics of metal materials based on their thermal treatment at elevated temperatures.

  14. Simulation on temperature field of TIG welding of copper without preheating

    Institute of Scientific and Technical Information of China (English)

    LEI Yu-cheng; YU Wen-xia; LI Cai-hui; CHENG Xiao-nong

    2006-01-01

    According to the conservation of energy principle and technology characteristics of tungsten inert gas(TIG), a model of non-steady three-dimensional temperature field for red copper's TIG welding with a locomotive arc was established. The temperature field of welding pool was calculated with finite element software ANSYS. Indrafted the heat enthalpy conception and the surface distribution dual-ellipsoid model, the demands of welding numerical simulation was primely satisfied. Aimed at bad weldability of red copper, the TIG welding of thick-wall red copper was studied adopting Ar+N2 without preheating. The results show that the heating effect of arc is evidently enhanced, it is viable to achieve the no preheating TIG welding of red copper. Comparing the experimental values with the calculated ones under different technological parameters, the results indicate that the model and practical course are well matched, which proves that the model is reliable and correct.

  15. Operation of a cyclonic preheater in the Ca-looping for CO2 capture.

    Science.gov (United States)

    Martínez, Ana; Lara, Yolanda; Lisbona, Pilar; Romeo, Luis M

    2013-10-01

    Calcium looping is an emerging technology for CO2 capture that makes use of the calcium oxide as a sorbent. One of its main issues is the significant energy consumption in the calciner, where the regeneration of the sorbent takes place. Nevertheless, as a high temperature looping technology, the surplus heat flows may be used to reduce the energy needs in this reactor. The addition of a cyclonic preheater similar to those used in the cement industry is proposed in this work. A calcium looping system was modeled and simulated to assess the advantages and disadvantages of the inclusion of a cyclonic preheater. Despite the negative effect on the maximum average capture capacity of the sorbent, a reduction on the coal and oxygen consumptions and on the extra CO2 generated in the calciner is obtained.

  16. Experimental investigations of the laser cladding of protective coatings on preheated base material

    Science.gov (United States)

    Jendrzejewski, Rafal; Sliwinski, Gerard; Conde, Ana; Navas, Carmen; de Damborenea, Juan J.

    2004-06-01

    The laser cladding technique was applied to obtain Co-based stellite SF6 coatings on the chromium steel base. The coatings were prepared by means of a direct cladding of metal powder using a 1.2 kW cw CO2 laser stand with a controlled preheating of the substrate material. Results of the metallographic tests revealed a fine-grained, dendritic microstructure and proper metallic bonding between substrate and coating. A nearly constant concentration of mian elements at different areas of the coating cross-section indicated on homogeneous chemical composition of the laser-cladded SF6 alloy samples. A significant decrease of the micro-crack number with increasing temperature of the base preheating was observed. This was accompanied by a drop of the wear and corrosion resistance.

  17. Gravitational Waves from Abelian Gauge Fields and Cosmic Strings at Preheating

    CERN Document Server

    Dufaux, Jean-Francois; Garcia-Bellido, Juan

    2010-01-01

    Primordial gravitational waves provide a very important stochastic background that could be detected soon with interferometric gravitational wave antennas or indirectly via the induced patterns in the polarization anisotropies of the cosmic microwave background. The detection of these waves will open a new window into the early Universe, and therefore it is important to characterize in detail all possible sources of primordial gravitational waves. In this paper we develop theoretical and numerical methods to study the production of gravitational waves from out-of-equilibrium gauge fields at preheating. We then consider models of preheating after hybrid inflation, where the symmetry breaking field is charged under a local U(1) symmetry. We analyze in detail the dynamics of the system in both momentum and configuration space, and show that gauge fields leave specific imprints in the resulting gravitational wave spectra, mainly through the appearence of new peaks at characteristic frequencies that are related to...

  18. Preheating after multifield inflation with nonminimal couplings, III: Dynamical spacetime results

    CERN Document Server

    DeCross, Matthew P; Prabhu, Anirudh; Prescod-Weinstein, Chanda; Sfakianakis, Evangelos I

    2016-01-01

    This paper concludes our semi-analytic study of preheating in inflationary models comprised of multiple scalar fields coupled nonminimally to gravity. Using the covariant framework of Ref. [1], we extend the rigid-spacetime results of Ref. [2] by considering both the expansion of the universe during preheating, as well as the effect of the coupled metric perturbations on particle production. The adiabatic and isocurvature perturbations are governed by different effective masses that scale differently with the nonminimal couplings and evolve differently in time. The effective mass for the adiabatic modes is dominated by contributions from the coupled metric perturbations immediately after inflation. The metric perturbations contribute an oscillating tachyonic term that enhances an early period of significant particle production for the adiabatic modes, which ceases on a time-scale governed by the nonminimal couplings $\\xi_I$. The effective mass of the isocurvature perturbations, on the other hand, is dominated...

  19. Heating of Intracluster Gas by Jet Activities of AGN Is the "Preheating" Scenario Realistic?

    CERN Document Server

    Yamada, M; Yamada, Masako; Fujita, Yutaka

    2001-01-01

    We investigate the non-gravitational heating of hot gas in clusters of galaxies (intracluster medium; ICM) on the assumption that the gas is heated well before cluster formation ('preheating'). We examine the jet activities of radio galaxies as the sources of excess energy in ICM, and the deformation of the cosmic microwave background (the Sunyaev-Zel'dovich effect) by hot electrons produced at the jet terminal shocks. We show that the observed excess entropy of ICM and {\\sl COBE/FIRAS} upper limit for the Compton $y$-parameter are compatible with each other only when the heating by the jets occurred at relatively small redshift ($z\\lesssim 3$). Since this result contradicts the assumption of 'preheating', it suggests that the heating occurred simultaneously with or after cluster formation.

  20. Specific Angular Momentum Distribution of Disc Galaxies Formed in Preheated Intergalactic Media

    Institute of Scientific and Technical Information of China (English)

    LUO Zhi-Jian; FU Li-Ping; SHU Cheng-Gang

    2004-01-01

    Assuming that baryons within a galactic halo have the same specific angular momentum as the dark matter where they locate initially and a disc forms due to the gas cooling and condensation with the conservation of angular momentum, we investigate the angular momentum distribution in a resulting galactic disc under the new preheated galaxy formation model suggested by Mo and Mao (Mon. Not. R. Astron. Soc. 333 (2002) 768).Compared with the observational results, it can be concluded that the preheated galaxy formation model can match current observations. This model can be a good approach to solve the problems of both the angular momentum catastrophe and the mismatch of angular-momentum profiles in current disc galaxy formation models.

  1. The Cluster Gas Mass - Temperature Relation Evidence for a High Level of Preheating

    CERN Document Server

    McCarthy, I G; Balogh, M L; Carthy, Ian G. Mc; Babul, Arif; Balogh, Michael L.

    2002-01-01

    Recent X-ray observations have been used to demonstrate that the cluster gas mass - temperature relation is steeper than theoretical self-similar predictions drawn from numerical simulations that consider the evolution of the cluster gas through the effects of gravity and shock heating alone. One possible explanation for this is that the gas mass fraction is not constant across clusters of different temperature, as usually assumed. Observationally, however, there is no compelling evidence for gas mass fraction variation, especially in the case of hot clusters. Seeking an alternative physical explanation for the observed trends, we investigate the role of preheating the intracluster medium by some arbitrary source on the cluster gas mass - temperature relation for clusters with emission-weighted mean temperatures of greater than about 3 keV. Making use of the physically-motivated, analytic model developed by Babul et al. (2002), we find that preheating does, indeed, lead to a steeper relation. This is in agree...

  2. Electronically Controlling the System of Preheating Intake Air by Flame for Diesel Engine Cold-Start

    Institute of Scientific and Technical Information of China (English)

    杜巍; 赵福堂

    2003-01-01

    In order to improve the cold-start performance of heavy duty diesel engine, electronically controlling the preheating of intake air by flame was researched. According to simulation and thermodynamic analysis about the partial working processes of the diesel engine, the amount of heat energy, enough to make the fuel self-ignite at the end of compression process at different temperatures of coolant and intake-air, was calculated. Several HY20 preheating plugs were used to heat up the intake air. Meanwhile, an electronic control system based on 8 bit micro-controller unit (MCS-8031) was designed to automatically control the process of heating intake air. According to the various temperatures of coolant and ambient air, one plug or two plugs can automatically be selected to heat intake air. The demo experiment validated that the total system could operate successfully and achieve the scheduled function.

  3. Effect of preheating on the film thickness of contemporary composite restorative materials

    OpenAIRE

    Dimitrios Dionysopoulos; Kosmas Tolidis; Paris Gerasimou; Eugenia Koliniotou-Koumpia

    2014-01-01

    Background/purpose: Recently, the placement of composite materials at an elevated temperature has been proposed in order to increase their flow for better adaptation in cavity walls. The aim of this in vitro study was to evaluate the effect of preheating on the film thickness of a variety of commercially available conventional composites and to compare them with those obtained from a variety of flowable composites at room temperature. Materials and methods: The composites were three nanohy...

  4. Preheating Cold Gas Thruster Flow Through a Thermal Energy Storage Conversion System

    Science.gov (United States)

    2013-01-01

    Journal Article 3. DATES COVERED (From - To) January 2013- October 2013 4. TITLE AND SUBTITLE Preheating Cold Gas Thruster Flow Through a Thermal Energy... Gas Thruster Flow through a Thermal Energy Storage Conversion System Michael R. Reid1 United States Air Force, Colorado Springs, CO, 80840 David B...specific impulse relative to a cold gas flow. Electric propulsion systems, the primary competitor to solar thermal propulsion systems, rely on the rather

  5. Acid skim milk gels: The gelation process as affected by preheated pH

    NARCIS (Netherlands)

    Lakemond, C.M.M.; Vliet, van T.

    2008-01-01

    The effect of preheating milk (10 min 80 [degree sign]C) at pH values from 6.20 to 6.90 on formation of acid skim milk gels was studied by dynamic oscillation measurements. Up to pH 6.65 a higher pH of heating (pHheating) resulted in a higher G'. Since below pH 4.9 the development of G'(pH)/G'(pH=4.

  6. Effect of preheating and light-curing unit on physicochemical properties of a bulk fill composite

    Directory of Open Access Journals (Sweden)

    Theobaldo JD

    2017-05-01

    Full Text Available Jéssica Dias Theobaldo,1 Flávio Henrique Baggio Aguiar,1 Núbia Inocencya Pavesi Pini,2 Débora Alves Nunes Leite Lima,1 Priscila Christiane Suzy Liporoni,3 Anderson Catelan3 1Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, 2Ingá University Center, Maringá, 3Departament of Dentistry, University of Taubaté, Taubaté, Brazil Objective: The aim of this study is to evaluate the effect of composite preheating and polymerization mode on degree of conversion (DC, microhardness (KHN, plasticization (P, and depth of polymerization (DP of a bulk fill composite.Methods: Forty disc-shaped samples (n = 5 of a bulk fill composite were prepared (5 × 4 mm thick and randomly divided into 4 groups according to light-curing unit (quartz–tungsten–halogen [QTH] or light-emitting diode [LED] and preheating temperature (23 or 54 °C. A control group was prepared with a flowable composite at room temperature. DC was determined using a Fourier transform infrared spectrometer, KHN was measured with a Knoop indenter, P was evaluated by percentage reduction of hardness after 24 h of ethanol storage, and DP was obtained by bottom/top ratio. Data were statistically analyzed by analysis of variance and Tukey’s test (α = 0.05.Results: Regardless of light-curing, the highest preheating temperature increased DC compared to room temperature on bottom surface. LED showed a higher DC compared to QTH. Overall, DC was higher on top surface than bottom. KHN, P, and DP were not affected by curing mode and temperature, and flowable composite showed similar KHN, and lower DC and P, compared to bulk fill.Conclusion: Composite preheating increased the polymerization degree of 4-mm-increment bulk fill, but it led to a higher plasticization compared to the conventional flowable composite evaluated. Keywords: composite resins, physicochemical phenomena, polymerization, hardness, heating

  7. The effect of preheating and opacity on the sorption and solubility of a composite resin.

    Science.gov (United States)

    Castro, Fabrício Luscino Alves de; Pazinatto, Flávia Bittencourt; de Lima, Érick; Cesar, Paulo Francisco; Reges, Rogério Vieira

    2016-01-01

    This study evaluated the influence of material opacity and preheating on the sorption and solubility of a composite resin material. A commercially available composite resin and an 8 × 2-mm circular metallic matrix were used to fabricate a total of 60 specimens in 6 shades, of which 3 had conventional opacity (CA2, CA3, and CA3.5) and 3 were opaque (OA2, OA3, and OA3.5). Specimens were prepared at a room temperature of 25°C or preheated to 60°C (n = 5 per shade at each temperature). The specimens were weighed 3 times: M1, dried for 24 hours at 37°C; M2, stored for 7 days in 75% ethanol at 37°C; and M3, dried for an additional 24 hours at 37°C. The weights were used to calculate the sorption and solubility of the composite resin and were analyzed using 2-way analysis of variance and Tukey tests (α = 5%). Composite resin specimens heated at 60°C yielded lower values of sorption and solubility than did specimens prepared at 25°C (P composite shades were found to be similar (P > 0.05), except for shade CA2, which presented a greater mean solubility value than OA2 (P = 0.004). Therefore, preheating was beneficial, as it lowered both the sorption and solubility of the evaluated composite resin, but opacity had little effect on these properties.

  8. Marginal and internal analysis of preheated dental fissure-sealing materials using optical coherence tomography.

    Science.gov (United States)

    Borges, Boniek Castillo Dutra; de Assunção, Isauremi Vieira; de Aquino, Célia Avani; de Melo Monteiro, Gabriela Queiroz; Gomes, Anderson Stevens Leonidas

    2016-02-01

    This study aimed to evaluate the influence of pre-photoactivation temperature on the marginal and internal integrity (occurrence of voids) of fissure-sealing materials on occlusal fissures using optical coherence tomography (OCT). Occlusal fissures of 40 human third molars were sealed using a resin-based fissure sealant (Fluroshield) and a flowable composite (Permaflo) photoactivated at 68 °C (preheated) or at room temperature (25 °C) (n=10). After sealing, the teeth were subjected to thermocycling (500 cycles, 5-55 °C) and 14 days of pH cycling (demineralisation for 6 hours/day and remineralisation for 18 hours/day). The occlusal surfaces were scanned in a buccolingual direction, and 20 tomographic images parallel to the long axis of each tooth were obtained. Images presenting marginal gaps and internal voids were counted and statistically analysed using analysis of variance and Tukey's test (Pinternal voids than the resin-based sealant. Preheated materials had a lower percentage of gaps and internal voids than the materials at room temperature. Therefore, preheated flowable composite provided the best marginal sealing of fissures, and internal homogeneity of the material. © 2015 FDI World Dental Federation.

  9. Influence of ageing, grinding and preheating on the thermal behaviour of alpha-lactose monohydrate.

    Science.gov (United States)

    Garnier, S; Petit, S; Mallet, F; Petit, M-N; Lemarchand, D; Coste, S; Lefebvre, J; Coquerel, G

    2008-09-01

    It is shown that the onset temperature and the magnitude of thermal events observed during DSC analyses of alpha-lactose monohydrate can be strongly affected by various treatments such as ageing, manual grinding and preheating (cycle of preliminary dehydration and rehydration). In the case of grinding and preheating, the change of dehydration pathways was further investigated by using a suitable combination of characterization techniques, including X-ray powder diffraction (XRPD) performed with a synchrotron source (allowing an accurate Rietveld analysis), scanning electron microscopy (SEM), laser particle size measurements, FTIR spectroscopy and (1)H NMR for the determination of beta-lactose contents in samples. It appeared that the dehydration mechanism is affected not only by a smaller particle size distribution, but also by residual anisotropic lattice distortions and by the formation of surface defects or high energy surfaces. The fusion-recrystallization process occurring between anhydrous forms of alpha-lactose at ca. 170 degrees C is not significantly affected by grinding, whereas a preheating treatment induces an unexpected large increase of the enthalpy associated with this transition. Our observations and interpretations confirm the important role of water molecules in the crystal cohesion of the title compound and illustrate the necessity to consider the history of each sample for a satisfactory understanding of the physical properties and the behaviour of this important pharmaceutical excipient.

  10. 空气预热器的改造%Revamping of air preheater

    Institute of Scientific and Technical Information of China (English)

    廖艳玲

    2011-01-01

    The revamping of air preheater in the waste heat recovery system of a 4.1 MM TPY diesel hy-drotreating unit in SINOPEC Qingdao Refining & Chemical Co. , Ltd. Was introduced. An analysis was performed on how to revamp the air preheater to reduce flue gas emission temperature of waste heat recovery system so as to improve the thermal efficiency of fired heaters. After revamping, the flue gas emission temperature is about 30 ℃ lower than that before the revamping, the thermal energy obtained by the air is much higher than that before replacement of pre-heater tubes and energy saving is significant.%介绍了中国石化青岛炼油化工有限责任公司余热回收系统的空气预热器的改造情况,分析了如何通过对空气预热器的改造来降低余热回收系统排烟温度,从而提高加热炉的热效率.改造后,烟气排烟温度比改造前降低30℃左右,空气所获得的能量比更换热管前有较大提高,节能效果显著.

  11. Study of laser preheat in magnetic liner inertial fusion using the AMR code FLASH

    Science.gov (United States)

    Adams, Marissa; Jennings, Christopher; Slutz, Stephen; Peterson, Kyle; Gourdain, Pierre-Alexandre; University of Rochester; Sandia National Laboratories Collaboration

    2016-10-01

    Magnetic Liner Inertial Fusion (MagLIF) on the Z Pulsed Power Accelerator involves three processes: magnetization, preheat, and compression. An issue with this scheme is the development of instabilities during laser preheat, where the Z-Beamlet laser system may not deposit energy into deuterium fuel uniformly. This study explores potential mixing between liner and fuel, and inner imprinting of seeds on a beryllium liner that may generate late instability growth and shear, using the Eulerian AMR code FLASH. We further investigate potential instability implications of an additional layer of deuterium-tritium ice, as has been proposed and assess the sensitivity of MagLIF implosions to axial variations in fuel preheat; meanwhile testing the expediency of FLASH for these scenarios. FLASH was developed in part by the DOE NNSA ASC and DOE Office of Science ASCR-supported Flash Center at the University of Chicago. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin comapny, for the U.S. Department of Energy's National Nuclear Security Administration under contract No. DE-AC04-94AL85000.

  12. Cryogenic Detectors (Narrow Field Instruments)

    Science.gov (United States)

    Hoevers, H.; Verhoeve, P.

    basic elements of the NFI 1 detector array. With a DROID-based array of 48 times 10 elements covering the NFI 1 field of view of 0.5 arcmin, the number of signal wires would already be reduced by a factor 2.4 compared to a 48 times 48 array of single pixels. While the present prototype DROIDS are still covered with a 480 nm thick SiOx insulation layer, this layer could easily be reduced in thickness or omitted. The detection efficiency of such a device with a 500 nm thick Ta absorber would be >80% in the energy range of 100-3000eV, without any disturbing contributions from other layers as in single STJs. Further developments involve devices of lower Tc-superconductors for better energy resolution and faster diffusion (e.g. Mo). The narrow field imager 2 The NFI 2 will consist of an array of 32 times 32 detector pixels. Each detector is a microcalorimeter which consists of a a superconducting to normal phase transition edge thermometer (transition edge sensor, TES) with an operating temperature of 100 mK, and an absorber which allows a detection efficiency of >90% and a filling factor of the focal plane in excess of 90%. Single pixel microcalorimeters with a Ti/Au TES have already shown an energy resolution of 3.9 eV at 5.89 keV in combination with a thermal response time of 100 mus. These results imply that they the high-energy requirement for XEUS can be met, in terms of energy resolution and response time. It has been demonstrated that bismuth can be applied as absorber material without impeding on the detector performance. Bi increases the stopping power in excess of 90 % and allows for a high filling factor since the absorber is can be modeled in the shape of a mushroom, allowing that the wiring to the detector and the thermal support structure are placed under the hat of the mushroom. In order to realize the NFI 2 detector array, there are two major development areas. Firstly, there is the development of micromachined Si and SiN structures that will provide proper

  13. Research on a Household Dual Heat Source Heat Pump Water Heater with Preheater Based on ASPEN PLUS

    Directory of Open Access Journals (Sweden)

    Xiang Gou

    2016-12-01

    Full Text Available This article proposes a dual heat source heat pump bathroom unit with preheater which is feasible for a single family. The system effectively integrates the air source heat pump (ASHP and wastewater source heat pump (WSHP technologies, and incorporates a preheater to recover shower wastewater heat and thus improve the total coefficient of performance (COP of the system, and it has no electric auxiliary heating device, which is favorable to improve the security of the system operation. The process simulation software ASPEN PLUS, widely used in the design and optimization of thermodynamic systems, was used to simulate various cases of system use and to analyze the impact of the preheater on the system. The average COP value of a system with preheater is 6.588 and without preheater it is 4.677. Based on the optimization and analysis, under the standard conditions of air at 25 °C, relative humidity of 70%, wastewater at 35 °C, wastewater flow rate of 0.07 kg/s, tap water at 15 °C, and condenser outlet water temperature at 50 °C, the theoretical COP of the system can reach 9.784 at an evaporating temperature of 14.96 °C, condensing temperature of 48.74 °C, and preheated water temperature of 27.19 °C.

  14. An Optimized Energy Management Strategy for Preheating Vehicle-Mounted Li-ion Batteries at Subzero Temperatures

    Directory of Open Access Journals (Sweden)

    Tao Zhu

    2017-02-01

    Full Text Available This paper presents an optimized energy management strategy for Li-ion power batteries used on electric vehicles (EVs at low temperatures. In low-temperature environments, EVs suffer a sharp driving range loss resulting from the energy and power capability reduction of the battery. Simultaneously, because of Li plating, battery degradation becomes an increasing concern as the temperature drops. All these factors could greatly increase the total vehicle operation cost. Prior to battery charging and vehicle operating, preheating the battery to a battery-friendly temperature is an approach to promote energy utilization and reduce total cost. Based on the proposed LiFePO4 battery model, the total vehicle operation cost under certain driving cycles is quantified in the present paper. Then, given a certain ambient temperature, a target preheating temperature is optimized under the principle of minimizing total cost. As for the preheating method, a liquid heating system is also implemented on an electric bus. Simulation results show that the preheating process becomes increasingly necessary with decreasing ambient temperature, however, the preheating demand declines as driving range grows. Vehicle tests verify that the preheating management strategy proposed in this paper is able to save on total vehicle operation costs.

  15. Experimental research on bitumen preheating (fluidization) by using solar energy in passive mode

    Energy Technology Data Exchange (ETDEWEB)

    Luminosu, Ioan [Department of Physics, ' Politehnica' University Timisoara, 1, Regina Maria Plaza, RO 300004, Timisoara (Romania); Fara, Laurentiu [Department of Physics, ' ' Politehnica' ' University Bucharest, 313, Splaiul Independentei Blvd, RO 060032, Bucuresti (Romania)

    2009-01-15

    An important aim of worldwide research engineering is to identify new industries to introduce solar energy installations for average thermal level. Due to the mechanical and thermal properties of bitumen, such as the 44-49 C softening point of D80/100 type bitumen, this material can be preheated by using solar thermal installations. The Physics Department of 'Politehnica' University of Timisoara designed and studied a laboratory installation for preheating in environmental conditions an amount of 25.1 kg of bitumen up to 55 C per day. The paper developed a previous original research regarding bitumen preheating by using solar energy. The experimental installation was improved and experimental data were statistically processed. The main improvements were based on:-increasing the amount of incident solar radiation by: (a) reducing the height of the brick walls and replacing them with transparent glass plates; (b) painting the inner faces of the brick walls in white; -cutting down thermal losses by: (a) achievement of the double greenhouse effect in the transparent areas of the installation; (b) change of the brick walls into passive walls. The performances of the installation were improved as follows:-increasing time of the bitumen temperature increased from 7 hours to 8 hours, in the interval 8 am-4 pm; -bitumen maximum temperature increased from 55 to 63.3 C; -average temperature in bitumen increased from 41.4 to 46.4 C; -maximum efficiency increased from 12 to 14.4%; -daily average efficiency increased from 6.3 to 7.3%; -maximum difference between the bitumen temperature and environmental one increased from 24 to 32 C. (author)

  16. Damage to Preheated Tungsten Targets after Multiple Plasma Impacts Simulating ITER ELMs

    Energy Technology Data Exchange (ETDEWEB)

    Garkusha, I.E.; Bandura, A.N.; Byrka, O.V.; Chebotarev, V.V.; Makhlay, V.A.; Tereshin, V.I. [Kharkov Inst. of Physics and Technology, Inst. of Plasma Physics of National Science Center, Akademicheskaya street, 1, 61108 Kharkov (Ukraine); Landman, I.; Pestchanyi, S. [FZK-Forschungszentrum Karlsruhe, Association Euratom-FZK, Technik und Umwelt, Postfach 3640, D-7602 1 Karlsruhe (Germany)

    2007-07-01

    Full text of publication follows: The energy loads onto ITER divertor surfaces associated with the Type I ELMs are expected to be up to 1 MJ/m{sup 2} during 0.1-0.5 ms, with the number of pulses about 103 per discharge. Tungsten is a candidate material for major part of the surface, but its brittleness can result in substantial macroscopic erosion after the repetitive heat loads. To minimize the brittle destruction, tungsten may be preheated above the ductile-to-brittle transition temperature. In this work the behavior of preheated tungsten targets under repetitive ELM-like plasma pulses is studied in simulation experiments with the quasi-stationary plasma accelerator QSPA Kh-50. The targets have been exposed up to 450 pulses of the duration 0.25 ms and the heat loads either 0.45 MJ/m{sup 2} or 0.75 MJ/m{sup 2}, which is respectively below and above the melting threshold. During the exposures the targets were permanently kept preheated at 650 deg. C by a heater at target backside. In the course of exposures the irradiated surfaces were examined after regular numbers of pulses using the SEM and the optical microscopy. The profilometry, XRD, microhardness and weight loss measurements have been performed, as well as comparisons of surface damages after the heat loads both below and above the melting threshold. It is obtained that macro-cracks do not develop on the preheated surface. After the impacts with surface melting, a fine mesh of intergranular microcracks has appeared. The width of fine intergranular cracks grows with pulse number, achieving 1-1.5 microns after 100 pulses, and after 210 pulses the crack width increases up to 20 microns, which is comparable with grain sizes. Threshold changes in surface morphology resulting in corrugation structures and pits on the surface as well as importance of surface tension in resulted 'micro-brush' structures are discussed. Further evolution of the surface pattern is caused by loss of separated grains on exposed

  17. Experimental data and boundary conditions for a Double - Skin Facade building in preheating mode

    DEFF Research Database (Denmark)

    Larsen, Olena Kalyanova; Heiselberg, Per; Jensen, Rasmus Lund

    was carried out in a full scale test facility ‘The Cube’, in order to compile three sets of high quality experimental data for validation purposes. The data sets are available for preheating mode, external air curtain mode and transparent insulation mode. The objective of this article is to provide the reader......’. This covers such problem areas as measurements of naturally induced air flow, measurements of air temperature under direct solar radiation exposure, etc. Finally, in order to create a solid foundation for software validation, the uncertainty and limitations in the experimental results are discussed. In part...

  18. Optimal Heater Control with Technology of Fault Tolerance for Compensating Thermoforming Preheating System

    Directory of Open Access Journals (Sweden)

    Zhen-Zhe Li

    2015-01-01

    Full Text Available The adjustment of heater power is very important because the distribution of thickness strongly depends on the distribution of sheet temperature. In this paper, the steady state optimum distribution of heater power is searched by numerical optimization in order to get uniform sheet temperature. In the following step, optimal heater power distribution with a damaged heater was found out using the technology of fault tolerance, which will be used to reduce the repairing time when some heaters are damaged. The merit of this work is that the design variable was the power of each heater which can be directly used in the preheating process of thermoforming.

  19. 垃圾焚烧发电厂一次风预热方式的比较分析%Comparison of Preheating Ways of Primary Air in Waste Incineration Power Plants

    Institute of Scientific and Technical Information of China (English)

    李军; 严圣军; 陈竹; 王占磊

    2012-01-01

    A comparison of heating medium in phase II of primary air preheater by ways of superheat steam and drum saturated steam for waste incineration power plants were carried out. The results showed that comparing with drum saturated steam, the weight of steam extraction with superheat steam decreased by 20. 8%, the heat quantity decreased by 8. 7%, the steam flow into the turbine increased, the heat exchanging area in phase II of the preheater can be reduced by about 20%, and the cost can be reduced by about 10%. The superheat steam has advantages of small investment cost, small steam consumption, and higher heat effective utilization. According to waste characteristic, incineration scale and control policy, it could give a reference to select preheat way of primary air, with the new ideas of primary air preheated by boiler feed water and the optimized air preheating way.%对垃圾焚烧发电厂一次风加热器Ⅱ段的加热介质采用锅炉出口过热蒸汽和汽包饱和蒸汽进行比较,结果表明:过热蒸汽抽汽较汽包饱和蒸汽抽汽的抽汽量减少20.8%,热量减少8.7%,并增加了进汽机的蒸汽量,同时预热器Ⅱ段换热面积可减少约20%,造价相应降低约10%.过热蒸汽加热有投资成本小、蒸汽耗量小、热量有效利用率高的优点.并通过锅炉给水预热一次风、优化的空气预热方式等新的一次风预热思路,供不同垃圾性质、焚烧规模、控制策略等选择一次风预热形式时参考.

  20. EFFECT OF STORAGE, PRE-HEATING AND TURNING DURING HOLDING PERIOD ON THE HATCHABILITY OF BROILER BREEDER EGGS

    Directory of Open Access Journals (Sweden)

    A. MAHMUD AND T. N. PASHA1

    2008-07-01

    Full Text Available Two hundred forty fertile eggs of an average weight of 52-55g were taken from 32 weeks old broiler breeder flock. These eggs were divided into four groups i.e. A (Without turning and preheating, B (No turning but preheated, C (Turned but without preheating, and D (given both treatments preheating and turning with 60 eggs in each group. The eggs were stored with broad end upward at 16-20°C and 65-75% humidity. After storage for 5 days, the pre-heating of eggs of groups B and D was performed in an incubator where hot air at 30°C temperature was circulated for 6-7 hours to provide gradual warmth to the eggs before setting in the same incubator. The temperature of the incubator was maintained at 37.6°C with relative humidity of 70%. The eggs of groups C and D were turned on hourly basis at an angle of about 45° till 17 days of incubation. The hatchability values of eggs of groups A, B, C and D were 88.30 ± 0.30, 76.30 ± 0.30, 83.30 ± 0.30 and 79.90 ± 0.10%, respectively. Statistical analysis of the data by Chi-square test showed non-significant differences among treatments.

  1. Waste Heat Recovery by Heat Pipe Air-Preheater to Energy Thrift from the Furnace in a Hot Forging Process

    Directory of Open Access Journals (Sweden)

    Lerchai Yodrak

    2010-01-01

    Full Text Available Problem statement: Currently, the heat pipe air-preheater has become importance equipment for energy recovery from industrial waste heat because of its low investment cost and high thermal conductivity. Approach: This purpose of the study was to design, construct and test the waste heat recovery by heat pipe air-preheater from the furnace in a hot brass forging process. The mathematical model was developed to predict heat transfer rate and applied to compute the heat pipe air-preheater in a hot brass forging process. The heat pipe air-preheater was designed, constructed and tested under medium temperature operating conditions with inlet hot gas ranging between 370-420°C using water as the working fluid with 50% filling by volume of evaporator length. Results: The experiment findings indicated that when the hot gas temperature increased, the heat transfer rate also increased. If the internal diameter increased, the heat transfer rate increased and when the tube arrangement changed from inline to staggered arrangement, the heat transfer rate increased. Conclusion/Recommendations: The heat pipe air-preheater can reduced the quantity of using gas in the furnace and achieve energy thrift effectively.

  2. Little evidence for entropy and energy excess beyond r500 - an end to ICM pre-heating?

    Science.gov (United States)

    Iqbal, Asif; Majumdar, Subhabrata; Nath, Biman B.; Ettori, Stefano; Eckert, Dominique; Malik, Manzoor A.

    2017-02-01

    Non-gravitational feedback affects the nature of the intracluster medium (ICM). X-ray cooling of the ICM and in situ energy feedback from active galactic nuclei (AGNs) and supernovae as well as pre-heating of the gas at epochs preceding the formation of clusters are proposed mechanisms for such feedback. While cooling and AGN feedbacks are dominant in cluster cores, the signatures of a pre-heated ICM are expected to be present even at large radii. To estimate the degree of pre-heating, with minimum confusion from AGN feedback/cooling, we study the excess entropy and non-gravitational energy profiles up to r200 for a sample of 17 galaxy clusters using joint data sets of Planck Sunyaev-Zel'dovich pressure and ROSAT/Position Sensitive Proportional Counter gas density profiles. The canonical value of pre-heating entropy floor of ≳300 keV cm2, needed in order to match cluster scalings, is ruled out at ≈3σ. We also show that the feedback energy of 1 keV particle-1 is ruled out at 5.2σ beyond r500. Our analysis takes both non-thermal pressure and clumping into account which can be important in outer regions. Our results based on the direct probe of the ICM in the outermost regions do not support any significant pre-heating.

  3. A simple method to prevent hard X-ray-induced preheating effects inside the cone tip in indirect-drive fast ignition implosions

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dongxiao; Shan, Lianqiang; Zhou, Weimin; Wu, Yuchi; Zhu, Bin; Zhang, Feng; Bi, Bi; Zhang, Bo; Zhang, Zhimeng; Shui, Min; He, Yingling; Gu, Yuqiu, E-mail: yqgu@caep.cn; Zhang, Baohan [Science and Technology on Plasma Physics Laboratory, China Academy of Engineering Physics, Mianyang 621900 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Peng, Xiaoshi; Xu, Tao; Wang, Feng; Yang, Zhiwen; Chen, Tao; Chen, Li; Chen, Ming [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); and others

    2016-06-15

    During fast-ignition implosions, preheating of inside the cone tip caused by hard X-rays can strongly affect the generation and transport of hot electrons in the cone. Although indirect-drive implosions have a higher implosion symmetry, they cause stronger preheating effects than direct-drive implosions. To control the preheating of the cone tip, we propose the use of indirect-drive fast-ignition targets with thicker tips. Experiments carried out at the ShenGuang-III prototype laser facility confirmed that thicker tips are effective for controlling preheating. Moreover, these results were consistent with those of 1D radiation hydrodynamic simulations.

  4. Direct Measurements of Hot-Electron Preheat in Inertial Confinement Fusion

    Science.gov (United States)

    Christopherson, A. R.; Betti, R.; Howard, J.; Bose, A.; Forrest, C. J.; Theobald, W.; Campbell, E. M.; Delettrez, J. A.; Stoeckl, C.; Edgell, D. H.; Seka, W.; Davis, A. K.; Michel, D. T.; Glebov, V. Yu.; Wei, M. S.

    2016-10-01

    In laser-driven inertial confinement fusion, a spherical capsule of cryogenic DT with a low- Z (CH, Be) ablator is accelerated inward on low entropy to achieve high hot-spot pressures at stagnation with minimal driver energy. Hot electrons generated from laser-plasma instabilities can compromise this performance by preheating the DT fuel, which results in early decompression of the imploding shell and lower hot-spot pressures. The hot-electron energy deposited into the DT for direct-drive implosions is routinely inferred by subtracting hard x-ray signals between a cryogenic implosion and its mass-equivalent, all-CH implosion. However, this technique does not measure the energy deposited into the unablated DT, which fundamentally determines the final degradation in hot-spot pressure. In this work, we report on experiments conducted with high- Z payloads of varying thicknesses to determine the hot-electron energy deposited into a payload that is mass equivalent to the amount of unablated DT present in typical DT layered implosions on OMEGA. These are the first measurements to directly probe the effect of preheat on performance degradation. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  5. Gasifier selection, design and gasification of oil palm fronds with preheated and unheated gasifying air.

    Science.gov (United States)

    Guangul, Fiseha M; Sulaiman, Shaharin A; Ramli, Anita

    2012-12-01

    Oil palm frond biomass is abundantly available in Malaysia, but underutilized. In this study, gasifiers were evaluated based on the available literature data and downdraft gasifiers were found to be the best option for the study of oil palm fronds gasification. A downdraft gasifier was constructed with a novel height adjustment mechanism for changing the position of gasifying air and steam inlet. The oil palm fronds gasification results showed that preheating the gasifying air improved the volumetric percentage of H(2) from 8.47% to 10.53%, CO from 22.87% to 24.94%, CH(4) from 2.02% to 2.03%, and higher heating value from 4.66 to 5.31 MJ/Nm(3) of the syngas. In general, the results of the current study demonstrated that oil palm fronds can be used as an alternative energy source in the energy diversification plan of Malaysia through gasification, along with, the resulting syngas quality can be improved by preheating the gasifying air.

  6. Developing a Pre-Heat Platform for MagLIF with Z-Beamlet

    Science.gov (United States)

    Geissel, Matthias; Harvey-Thompson, Adam J.; Awe, T. J.; Bliss, D. E.; Glinsky, M. E.; Campbell, E. M.; Gomez, M. R.; Harding, E.; Hansen, S. B.; Jennings, C. A.; Kimmel, M. W.; Knapp, P. F.; Lewis, S. M.; McBride, R. D.; Peterson, K.; Schollmeier, M.; Scoglietti, D. J.; Sefkow, A. B.; Shores, J. E.; Sinars, D. B.; Rochau, G. A.; Slutz, S. A.; Smith, I. C.; Weiss, M. R.; Porter, J. L.

    2016-10-01

    Sandia's Magnetized Liner Inertial Fusion Program has put one of the main objectives towards developing standard platform for a `preconditioned' target, providing a scenario that reproducibly delivers pre-heated fuel. The majority of this effort has been done at the ``Pecos'' Target Area using Sandia's Z-Beamlet laser to provide the pre-heat energy, just like for fully integrated MagLIF experiments. The nature and magnitude of Laser-Plasma-Instabilities during this process are particularly important, since they can lead to less energy in the fuel (backscatter processes) or to energy deposition in less desirable areas (filamentation/scatter). We present results for Stimulated Brillouin Backscatter and forward scatter, and show the effect of the laser pulse shape to laser-entrance-hole transmission and blast wave propagation in the fuel. Sandia is a multi-program laboratory managed and operated by Sandia Corp., a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. DOE's Nat'l Nucl. Sec. Admin. under contract DE-AC04-94AL85000.

  7. Combustion Air Pre-heating from Ash Sensible Heat in Municipal Waste Incineration Systems

    Directory of Open Access Journals (Sweden)

    Zakariya Kaneesamkandi

    2014-01-01

    Full Text Available Heat recovery from bottom ash is more important in municipal waste combustion systems than in any other solid fuel combustion since almost 50% of it comprises of non-combustibles. In this study, an ash cooling system using air as the cooling medium has been modeled for pre-heating the combustion air. Air cooling has several advantages over water cooling methods. The study involves modeling using Gambit tool and is solved with the fluent solver. Municipal solid waste incineration systems have the advantage of being located near the waste collection area apart from the high volume reduction ratio. Improvements in the emission control systems and combustion technology can make incineration a highly feasible disposal method. Low furnace temperature due to heat losses through fuel moisture loss and ash sensible heat loss has been a disadvantage with these systems. In this study, a small percentage of the combustion air is pre-heated in a non-contact type heat exchanger and its effect on the available energy of combustion gases at the evaporator outlet is studied. The study is performed for two different waste samples. Results indicate significant increase in available energy at the evaporator outlet and better relative performance for the lower grade fuel. A comparison is made with similar methods reported in the literature along with a brief discussion on the methodologies adopted. The results confirm the importance of installing ash sensible heat recovery mechanism for waste incineration systems as well as the feasibility of the air based method.

  8. Velocity Interferometer blanking due to preheating in a double pulse planar experiment

    Energy Technology Data Exchange (ETDEWEB)

    Laffite, S.; Combis, P.; Clerouin, J.; Recoules, V.; Rousseaux, C.; Videau, L. [CEA, DAM, DIF, F-91297 Arpajon (France); Baton, S. D.; Koenig, M. [LULI, Ecole Polytechnique, CNRS, CEA, UPMC, route de Saclay, 91128 Palaiseau (France)

    2014-08-15

    Optical diagnostics, such as VISAR (Velocity Interferometer System for Any Reflector) or SOP (Streaked Optical Pyrometry), have become essential in shock timing experiments. Their high precision allows for accurate measurements of shock velocities, chronometry, and brightness temperature. However, in some instances, these measurements can be compromised. In planar shock coalescence experiments recently performed at the LULI facility [Baton et al., Phys. Rev. Lett. 108, 195002 (2012)], VISAR signal loss was observed. In these experiments, a strong shock launched by a high-intensity spike catches up with a previously shock launched by an earlier, low-intensity beam. The disappearance of the VISAR signal is attributed to a preheating of the coronal plasma by x-rays generated by the high intensity spike. The signal does not disappear if the high-intensity spike starts after VISAR probe beam begins to reflect off of the first shock. The VISAR diagnostic, modeled using an assessment of the optical index in quartz, compares favorably to experimental results. This provides evidence that x-ray preheating can cause blanking of the VISAR signal in quartz.

  9. Investigation of Thermal Conductivity and Heat Characteristics of Oil Sands Using Ultrasound Irradiation for Shortening the Preheating Time

    Science.gov (United States)

    Kamagata, Shingo; Kawamura, Youhei; Okawa, Hirokazu; Mizutani, Koichi

    2012-07-01

    Oil sands are attractive as an energy resource. Bitumen, which is found in oil sands, has high viscosity, so that it does not flow. Most oil sands are underground and are developed with a method called steam-assisted gravity drainage (SAGD). Hot steam is injected underground to fluidize bitumen and promote its recovery. However, the preheating time is too long. One way of reducing running costs is by shortening the preheating time. Previous studies have found that bitumen can be extracted from oil sands efficiently by applying ultrasonic irradiation, but SAGD was not applied directly in these cases. Thus, the purpose of this study is to apply ultrasonic irradiation to SAGD, thereby shortening the preheating time of oil sands. As a model experiment for SAGD, heat transfer experiments in a sand layer made with Toyoura sand and silicone oil were conducted and the thermal effect with ultrasound was investigated.

  10. The effect of repeated preheating of dimethacrylate and silorane-based composite resins on marginal gap of class V restorations

    Directory of Open Access Journals (Sweden)

    Parnian Alizadeh Oskoee

    2017-03-01

    Full Text Available Background. One of the problems with composite resin restorations is gap formation at resin‒tooth interface. The present study evaluated the effect of preheating cycles of silorane- and dimethacrylate-based composite resins on gap formation at the gingival margins of Class V restorations. Methods. In this in vitro study, standard Class V cavities were prepared on the buccal surfaces of 48 bovine incisors. For restorative procedure, the samples were randomly divided into 2 groups based on the type of composite resin (group 1: di-methacrylate composite [Filtek Z250]; group 2: silorane composite [Filtek P90] and each group was randomly divided into 2 subgroups based on the composite temperature (A: room temperature; B: after 40 preheating cycles up to 55°C. Marginal gaps were measured using a stereomicroscope at ×40 and analyzed with two-way ANOVA. Inter- and intra-group comparisons were analyzed with post-hoc Tukey tests. Significance level was defined at P < 0.05. Results. The maximum and minimum gaps were detected in groups 1-A and 2-B, respectively. The effects of composite resin type, preheating and interactive effect of these variables on gap formation were significant (P<0.001. Post-hoc Tukey tests showed greater gap in dimethacrylate compared to silorane composite resins (P< 0.001. In each group, gap values were greater in composite resins at room temperature compared to composite resins after 40 preheating cycles (P<0.001. Conclusion. Gap formation at the gingival margins of Class V cavities decreased due to preheating of both composite re-sins. Preheating of silorane-based composites can result in the best marginal adaptation.

  11. First Results from Laser-Driven MagLIF Experiments on OMEGA: Backscatter and Transmission Measurements of Laser Preheating

    Science.gov (United States)

    Davies, J. R.; Barnak, D. H.; Betti, R.; Chang, P.-Y.

    2015-11-01

    A laser-driven version of MagLIF (magnetized liner inertial fusion) is being developed on the OMEGA laser. In the first experiment, laser preheating with a single OMEGA beam was studied. Laser energies of 60 to 200 J in 2.5-ns-long pulses were used, with a distributed phase plate giving a Gaussian intensity profile with a 96 μm full width at half maximum. We report on backscatter measurements from gas-filled cylinders and both backscatter and transmission measurements from the 1.84- μm-thick polyimide foils used for the laser entrance windows. Backscatter spectra and energies from both cylinders and foils alone were very similar. Approximately 0.5% of the total incident laser energy was backscattered. Backscattering lasted for little more than 0.5 ns. The fraction of laser energy transmitted through foils within the original beam path increased from 50% to 64% as the laser energy was increased from 60 to 200 J. Up to 10% of the laser energy was sidescattered as the foil started to transmit. Sidescattering of transmitted light lasted ~0.5 ns. The sidescattering might be avoided by using a short prepulse at least 0.5 ns prior to the main pulse. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and by DE-FG02-04ER54786 and DE-FC02-04ER54789 (Fusion Science Center).

  12. Kinetic narrowing of size distribution

    Science.gov (United States)

    Dubrovskii, V. G.

    2016-05-01

    We present a model that reveals an interesting possibility for narrowing the size distribution of nanostructures when the deterministic growth rate changes its sign from positive to negative at a certain stationary size. Such a behavior occurs in self-catalyzed one-dimensional III-V nanowires and more generally whenever a negative "adsorption-desorption" term in the growth rate is compensated by a positive "diffusion flux." By asymptotically solving the Fokker-Planck equation, we derive an explicit representation for the size distribution that describes either Poissonian broadening or self-regulated narrowing depending on the parameters. We show how the fluctuation-induced spreading of the size distribution can be completely suppressed in systems with size self-stabilization. These results can be used for obtaining size-uniform ensembles of different nanostructures.

  13. "Credit Markets and Narrow Banking"

    OpenAIRE

    Ronnie Phillips

    1992-01-01

    Maurice Allais's view that the credit created by fractional reserve banking is equivalent to counterfeiting has led him to recommend the separation of the depository and lending functions of banks. This proposal has recently been reintroduced by James Tobin and others under the term "narrow banking." Proponents cite the potential for enhanced safety of the payments mechanism and the elimination of costs associated with the preses system of Federal deposit insurance. This plan resembles the "1...

  14. Damage to preheated tungsten targets after multiple plasma impacts simulating ITER ELMs

    Energy Technology Data Exchange (ETDEWEB)

    Garkusha, I.E. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine)], E-mail: garkusha@ipp.kharkov.ua; Bandura, A.N.; Byrka, O.V.; Chebotarev, V.V. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine); Landman, I. [Forschungszentrum Karlsruhe, IHM, 76021 Karlsruhe (Germany); Makhlaj, V.A. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine); Pestchanyi, S. [Forschungszentrum Karlsruhe, IHM, 76021 Karlsruhe (Germany); Tereshin, V.I. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine)

    2009-04-30

    The behavior of a preheated at 650 deg. C tungsten targets under repetitive ELM-like plasma pulses is studied in simulation experiments with the quasi-stationary plasma accelerator QSPA Kh-50. The targets have been exposed up to 350 pulses of the duration 0.25 ms and the surface heat loads either 0.45 MJ/m{sup 2} or 0.75 MJ/m{sup 2}, which is below and above the melting threshold, respectively. The development of surface morphology of the exposed targets as well as cracking and swelling at the surface is discussed. First comparisons of obtained experimental results with corresponding numerical simulations of the code PEGASUS-3D are presented.

  15. Effect of diluted and preheated oxidizer on the emission of methane flameless combustion

    Science.gov (United States)

    Hosseini, Seyed Ehsan; Salehirad, Saber; Wahid, M. A.; Sies, Mohsin Mohd; Saat, Aminuddin

    2012-06-01

    In combustion process, reduction of emissions often accompanies with output efficiency reduction. It means, by using current combustion technique it is difficult to obtainlow pollution and high level of efficiency in the same time. In new combustion system, low NOxengines and burners are studied particularly. Recently flameless or Moderate and Intensive Low oxygen Dilution (MILD) combustion has received special attention in terms of low harmful emissions and low energy consumption. Behavior of combustion with highly preheated air was analyzed to study the change of combustion regime and the reason for the compatibility of high performance and low NOx production. Sustainability of combustion under low oxygen concentration was examined when; the combustion air temperature was above the self-ignition temperature of the fuel. This paper purposes to analyze the NOx emission quantity in conventional combustion and flameless combustion by Chemical Equilibrium with Applications (CEA) software.

  16. Effects of Preheating and Storage Temperatures on Aroma Profile and Physical Properties of Citrus-Oil Emulsions.

    Science.gov (United States)

    Yang, Ying; Zhao, Chengying; Tian, Guifang; Lu, Chang; Zhao, Shaojie; Bao, Yuming; McClements, David Julian; Xiao, Hang; Zheng, Jinkai

    2017-09-06

    Citrus oils are used as good carrier oil for emulsion fabrication due to their special flavor and various health-promoting functions. In this study, the effects of preheating temperature (30, 40, 50, 60, and 70 °C) and storage temperature (4, 25, and 37 °C) on aroma profiles and physical properties of three citrus-oil (i.e., mandarin, sweet orange, and bergamot oils) emulsions were systematically investigated for the first time. The results demonstrated the significant impact of temperature on aroma profile and physical properties. The abundance of d-limonene was found to be the main factor determining the aroma of the three citrus-oil emulsions at different preheating and storage temperatures, while β-linalool and linalyl acetate were important for the aroma of bergamot oil emulsion. Preheating temperature showed a profound impact on the aroma of citrus-oil emulsions, and the aroma of different citrus oil emulsions showed different sensitivity to preheating temperature. Storage temperature was also able to alter the properties of citrus oil emulsions. The higher was the storage temperature, the more alteration of aroma and more instability of the emulsions there was, which could be attributed to the alteration of the oil components and the properties of emulsions. Among all three emulsions, bergamot-oil emulsion was the most stable and exhibited the most potent ability to preserve the aroma against high temperature. Our results would facilitate the application of citrus-oil emulsions in functional foods and beverages.

  17. Effect Of Preheating And Different Moisture Content Of Input Materials On Durability Of Pellets Made From Different Phytomass Content

    Directory of Open Access Journals (Sweden)

    Macák Miroslav

    2015-03-01

    Full Text Available This paper analyses the effects of the storage process on the durability of pellets made of different types of biomass (lucerne hay, maize stover, wheat straw, miscanthus, prickly lettuce for energy purposes. Pellets were produced on a hydraulic press that allowed modifying the size of pellets. The durability of pellets was measured on a special testing instrument according to the ASAE S269.4 (2007 standard method. The pellets used in the test were produced by pressing without preheating and with preheating. Durability rating was expressed as the ratio of the original mass of pellets and the mass of pellets remaining on a 17 mm opening sieve after tumbling. Storage negatively affected the durability of pellets made without preheating for all the types of biomass materials in different moisture contents. On the other hand, there was some positive response to storing of pellets made with preheating. The durability of pellets made of maize stover, wheat straw and miscanthus in the moisture content of 5 % increased with storing.

  18. Effect of Preheating on the Inertia Friction Welding of the Dissimilar Superalloys Mar-M247 and LSHR

    Science.gov (United States)

    Senkov, O. N.; Mahaffey, D. W.; Semiatin, S. L.

    2016-12-01

    Differences in the elevated temperature mechanical properties of cast Mar-M247 and forged LSHR make it difficult to produce sound joints of these alloys by inertia friction welding (IFW). While extensive plastic upset occurs on the LSHR side, only a small upset is typically developed on the Mar-M247 side. The limited plastic flow of Mar-M247 thus restricts the extent of "self-cleaning" and mechanical mixing of the mating surfaces, so that defects remain at the bond line after welding. In the present work, the effect of local preheating of Mar-M247 immediately prior to IFW on the welding behavior of Mar-M247/LSHR couples was determined. An increase in the preheat temperature enhanced the plastic flow of Mar-M247 during IFW, which resulted in extensive mechanical mixing with LSHR at the weld interface, the formation of extensive flash on both the Mar-M247 and LSHR sides, and a sound bond. Performed in parallel with the experimental work, finite-element-method (FEM) simulations showed that higher temperatures are achieved within the preheated sample during IFW relative to its non-preheated counterpart, and plastic flow is thus facilitated within it. Microstructure and post-weld mechanical properties of the welded samples were also established.

  19. 矩形窄缝通道内单相水流动特性研究%Research on Characteristics of Single-Phase Water Flow in Narrow Rectangular Channel

    Institute of Scientific and Technical Information of China (English)

    幸奠川; 阎昌琪; 曹夏昕; 刘宇生; 谢清清

    2011-01-01

    A calculation formulation for laminar friction coefficient in narrow rectangular channel was obtained by theoretical analysis. Experiments have been made on flow characteristics in narrow rectangular channels with low aspect ratios, and the results show that the curve of friction coefficients in rectangular channel varying with Reynolds number is similar to that in round pipe. The conventional frictional correlations based on circular pipes are not available for rectangular channels, which depend on Reynolds numbers and aspect ratios, and the friction coefficient increases as the aspect ratio decreases. The experimental results agree well with the theoretical analysis. The effects of aspect ratios on frictional characteristics in laminar flow were explained by taking into account wetting perimeter and shear stress.%通过理论分析,得到了计算矩形窄缝通道单相层流摩阻系数的公式.对小高宽比矩形窄缝通道内的流动特性进行了实验研究,结果表明:矩形窄缝通道内单相摩阻系数随Re变化的曲线和圆管有相同的趋势,但圆管流动摩阻公式不适用于矩形窄缝通道.矩形通道内摩阻系数与Re和通道截面高宽比有关,通道高宽比越小,摩阻系数越大.实验结果和理论推导结论一致.从截面湿周和切向应力两方面解释了高宽比对矩形窄缝通道内单相水层流摩阻特性的影响机理.

  20. Narrow-angle astrometry with PRIMA

    CERN Document Server

    Sahlmann, J; Mérand, A; Zimmerman, N; Abuter, R; Chazelas, B; Delplancke, F; Henning, T; Kaminski, A; Köhler, R; Launhardt, R; Mohler, M; Pepe, F; Queloz, D; Quirrenbach, A; Reffert, S; Schmid, C; Schuhler, N; Schulze-Hartung, T

    2012-01-01

    The Extrasolar Planet Search with PRIMA project (ESPRI) aims at characterising and detecting extrasolar planets by measuring the host star's reflex motion using the narrow-angle astrometry capability of the PRIMA facility at the Very Large Telescope Interferometer. A first functional demonstration of the astrometric mode was achieved in early 2011. This marked the start of the astrometric commissioning phase with the purpose of characterising the instrument's performance, which ultimately has to be sufficient for exoplanet detection. We show results obtained from the observation of bright visual binary stars, which serve as test objects to determine the instrument's astrometric precision, its accuracy, and the plate scale. Finally, we report on the current status of the ESPRI project, in view of starting its scientific programme.

  1. Driven tracers in narrow channels

    Science.gov (United States)

    Cividini, J.; Mukamel, D.; Posch, H. A.

    2017-01-01

    Steady-state properties of a driven tracer moving in a narrow two-dimensional (2D) channel of quiescent medium are studied. The tracer drives the system out of equilibrium, perturbs the density and pressure fields, and gives the bath particles a nonzero average velocity, creating a current in the channel. Three models in which the confining effect of the channel is probed are analyzed and compared in this study: the first is the simple symmetric exclusion process (SSEP), for which the stationary density profile and the pressure on the walls in the frame of the tracer are computed. We show that the tracer acts like a dipolar source in an average velocity field. The spatial structure of this 2D strip is then simplified to a one-dimensional (1D) SSEP, in which exchanges of position between the tracer and the bath particles are allowed. Using a combination of mean-field theory and exact solution in the limit where no exchange is allowed gives good predictions of the velocity of the tracer and the density field. Finally, we show that results obtained for the 1D SSEP with exchanges also apply to a gas of overdamped hard disks in a narrow channel. The correspondence between the parameters of the SSEP and of the gas of hard disks is systematic and follows from simple intuitive arguments. Our analytical results are checked numerically.

  2. Spectral Narrowing in Semiconductor Microcavities

    Science.gov (United States)

    La Rocca, G. C.; Bassani, F.; Agranovich, V. M.

    1998-03-01

    The notion of in-plane motional narrowing of cavity polariton (CP) lines has been recently considered ( D.M. Whittaker et al.), Phys. Rev. Lett. 77, 4792 (1996); V. Savona et al.. Phys. Rev. Lett. 78, 4470 (1997). We point out that, in the presence of N>1 resonating quantum wells (QWs), the exciton component in a CP is coherently delocalized over all the individual QWs. Besides the two CP branches, also a dark exciton branch is present given by N-1 states similarly delocalized, but orthogonal to the cavity photon mode. If the QW disorder potential is weak compared to the Rabi splitting, it is seen by a CP as reduced by a factor 1/√N because of averaging along the cavity axis (G.C. La Rocca, F. Bassani, V.M. Agranovich, JOSA B 15), (1998). As for the in-plane motional narrowing, a simple scaling procedure shows that it would imply that the inhomogeneous linewidth of a CP be reduced by about four orders of magnitude compared to a QW exciton, which is incompatible with the experimental observations. The physical reason of such a shortcoming is that the disorder introduces localized exciton states which can resonantly scatter CPs, mixing them with states having a large k vector as well as with dark exciton states.

  3. Oscillatory quantum interference effects in narrow-gap semiconductor heterostructures

    Science.gov (United States)

    Lillianfeld, R. B.; Kallaher, R. L.; Heremans, J. J.; Chen, Hong; Goel, N.; Chung, S. J.; Santos, M. B.; Van Roy, W.; Borghs, G.

    2010-01-01

    We investigate quantum interference phenomena in narrow bandgap semiconductors under strong spin-orbit interaction, by measuring the magnetoresistance across mesoscopic closed-path structures fabricated in two-dimensional electron systems. We discuss our results in terms of four quantum interference effects brought about by geometric phases acquired by the electron wave functions: the Aharonov-Bohm phase, the Altshuler-Aronov-Spivak effect, the Berry's phase due to the evolution of the spin degree of freedom, and the Aharonov-Casher phase.

  4. Structural phase transition, narrow band gap, and room-temperature ferromagnetism in [KNbO{sub 3}]{sub 1−x}[BaNi{sub 1/2}Nb{sub 1/2}O{sub 3−δ}]{sub x} ferroelectrics

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Wenliang; Yang, Pingxiong, E-mail: pxyang@ee.ecnu.edu.cn; Chu, Junhao [Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China); Deng, Hongmei [Instrumental Analysis and Research Center, Institute of Materials, Shanghai University, 99 Shangda Road, Shanghai 200444 (China)

    2014-09-15

    Structural phase transition, narrow band gap (E{sub g}), and room-temperature ferromagnetism (RTFM) have been observed in the [KNbO{sub 3}]{sub 1−x}[BaNi{sub 1/2}Nb{sub 1/2}O{sub 3−δ}]{sub x} (KBNNO) ceramics. All the samples have single phase perovskite structure, but exhibit a gradual transition behaviour from the orthorhombic to a cubic structure with the increase of x. Raman spectroscopy analysis not only corroborates this doping-induced change in normal structure but also shows the local crystal symmetry for x ≥ 0.1 compositions to deviate from the idealized cubic perovskite structure. A possible mechanism for the observed specific changes in lattice structure is discussed. Moreover, it is noted that KBNNO with compositions x = 0.1–0.3 have quite narrow E{sub g} of below 1.5 eV, much smaller than the 3.2 eV band gap of parent KNbO{sub 3} (KNO), which is due to the increasing Ni 3d electronic states within the gap of KNO. Furthermore, the KBNNO materials present RTFM near a tetragonal to cubic phase boundary. With increasing x from 0 to 0.3, the magnetism of the samples develops from diamagnetism to ferromagnetism and paramagnetism, originating from the ferromagnetic–antiferromagnetic competition. These results are helpful in the deeper understanding of phase transitions, band gap tunability, and magnetism variations in perovskite oxides and show the potential role, such materials can play, in perovskite solar cells and multiferroic applications.

  5. Broad Diphotons from Narrow States

    CERN Document Server

    An, Haipeng; Zhang, Yue

    2015-01-01

    ATLAS and CMS have each reported a modest diphoton excess consistent with the decay of a broad resonance at ~ 750 GeV. We show how this signal can arise in a weakly coupled theory comprised solely of narrow width particles. In particular, if the decaying particle is produced off-shell, then the associated diphoton resonance will have a broad, adjustable width. We present simplified models which explain the diphoton excess through the three-body decay of a scalar or fermion. Our minimal ultraviolet completion is a weakly coupled and renormalizable theory of a singlet scalar plus a heavy vector-like quark and lepton. The smoking gun of this mechanism is an asymmetric diphoton peak recoiling against missing transverse energy, jets, or leptons.

  6. Shock experiments on pre-heated alpha- and beta-quartz: 1. Optical and density data

    Science.gov (United States)

    Langenhorst, Falko; Deutsch, Alexander

    1994-07-01

    Discs of single crystal quartz, unheated, and pre-heated to 275 C and 540 C (i.e., alpha-quartz) and 630 C (i.e., beta-quartz) were experimentally shocked to pressures ranging from 20 to 40 GPa, with the shock front propagating parallel to either (10-10) or (0001). Refractive indices, density and the orientation of planar deformation features (PDFs) were determined on the recovered quartz samples. Refractive indices of pre-heated quartz are unaffected up to 25 GPa but density starts to decrease slightly up to this pressure. Above 25 GPa, pre-heating causes drastic variations: Refractive indices and birefringence of quartz shocked at ambient temperature decrease continuously, until complete isotropization is reached at 35 GPa. In quartz shocked at 630 C, refractivity drops discontinuously in the interval from 25 to 26 GPa, and complete transformation to diaplectic glass is reached at 26 GPa. Density follows the trends demonstrated by the optical parameters, with higher pre-shock temperatures yielding lower density at a given shock pressure. These results indicate that the threshold pressure for the onset of transformation to diaplectic quartz glass is largely temperature-invariant, lying at 25 GPa, whereas the pressure limit for complete transformation decreases with increasing pre-shock temperature from approximately equal 35 to approximately equal 26 GPa. Quartz shocked parallel to (0001) always has a higher density and refractivity than that shocked parallel to (10-10), indicating a significant influence of the structural anisotropy. This is also evident from the distribution of PDF orientations. Pressures greater than or equal 25 GPa cause, in quartz shocked parallel to (10-10), PDFs that are predominantly oriented parallel to set of (10-12) planes, while quartz shocked to the same pressures but parallel to (0001) contains almost exclusively PDFs parallel to set of (10-13) planes. PDF orientations in quartz shocked at ambient temperature parallel to (10-10) show

  7. An economic and performance design study of solar preheaters for domestic hot water heaters in North Carolina

    Energy Technology Data Exchange (ETDEWEB)

    Jones, C.B.; Smetana, F.O.

    1977-03-01

    The performance and estimated material costs for several solar preheaters for domestic hot water heaters using insolation levels present in North Carolina are presented. The effects of monthly variations in insolation and the direction of incident radiation are included. Demand is assumed at 13 gallons (49.2 liters) per day per person. The study shows that a closed circulation system with 82 gallons (310 liters) of preheated storage and 53.4 cu ft (4.94 cu m) of collector surface with single cover can be expected to cost about $800 and to repay it capital cost and interest (at 8%) in 5.2 years, assuming present electric rates increase at 5% per year.

  8. An economic and performance design study of solar preheaters for domestic hot water heaters in North Carolina

    Science.gov (United States)

    Jones, C. B.; Smetana, F. O.

    1977-01-01

    The performance and estimated material costs for several solar preheaters for domestic hot water heaters using isolation levels present in North Carolina are presented. The effects of monthly variations in isolation and the direction of incident radiation are included. Demand is assumed at 13 gallons (49.2 liters) per day per person. The study shows that a closed circulation system with 82 gallons (310 liters) of preheated storage and 53.4 cu ft (4.94 cu m) of collector surface with single cover can be expected to cost about $800 and to repay it capital cost and interest (at 8%) in 5.2 years, assuming present electric rates increase at 5% per year.

  9. Design of a DCS Based Model for Continuous Leakage Monitoring System of Rotary Air Preheater of a Thermal Power Plant

    Directory of Open Access Journals (Sweden)

    Madan BHOWMICK

    2011-01-01

    Full Text Available The leakage in rotary air preheater makes a considerable contribution to the reduced overall efficiency of fossil-fuel-fired thermal power plants and increase the effect on environment. Since it is normal phenomenon, continuous monitoring of leakage is generally omitted in most power plants. But for accurate analysis of the operation of the thermal power plant, this leakage monitoring plays a vital role. In the present paper, design of a DCS based model for continuous leakages monitoring of rotary air preheater has been described. In the proposed model, the existing DCS based instrumentation system has been modified and online leakage monitoring system has been developed. This model has been installed in a captive power plant with high capacity boilers and very much satisfactory operation of this system has been observed. The observed online data along with their analysis results are presented in this paper.

  10. GMA-laser Hybrid Welding of High-strength Fine-grain Structural Steel with an Inductive Preheating

    Science.gov (United States)

    Lahdo, Rabi; Seffer, Oliver; Springer, André; Kaierle, Stefan; Overmeyer, Ludger

    The industrial useof GMA-laser hybrid welding has increased in the last 10 years, due to the brilliant quality of the laser beam radiation, and higher laser output powers. GMA-laser hybrid welding processes operate in a common molten pool. The combination of the laser beam and the arc results in improved welding speed, penetration depth, heat affected zone and gap bridgeability. Single-layer, GMA-laser hybrid welding processes have been developed for high-strength fine-grain structural steels with a grade of S690QL and a thickness of 15 mm and 20 mm. In addition, the welding process is assisted by an integrated, inductive preheating process to improve the mechanical properties of the welding seam. By using the determined parameters regarding the energy per unit length, and the preheating temperature, welding seams with high quality can be achieved.

  11. Application of a Device for Uniform Web Drying and Preheating Using Microwave Energy

    Energy Technology Data Exchange (ETDEWEB)

    Frederick W. Ahrens; C. Habeger; J. Loughran; T. Patterson

    2003-10-02

    The project summarized in this report dealt with an evaluation of new microwave applicator ideas for paper preheating and drying. The technical basis for success in this project is the fact that Industrial Microwave Systems has recently identified certain previously unrecognized wave guide ''design variables'' and hardware implementation concepts that can be employed to greatly improve the uniformity of microwave energy distribution for continuous flow processes. Two applicator concepts were ultimately evaluated, a Cross-Machine Direction (CD) oriented applicator and a Machine Direction (MD) oriented applicator. The economic basis for success is the result of several factors. Since 1985, the capital expenditure required for an industrial microwave applicator system has decreased by a factor of four. The maintenance costs have decreased by a factor of 10 and the life expectancy of the magnetron has increased by more than a factor of four to in excess of 8,000 hours (nearly one year at 24 hours/day operation).

  12. FAILURE ANALYSIS IN TUBING OF AIR PREHEATER OF BOILER FROM A SUGARCANE MILL

    Directory of Open Access Journals (Sweden)

    Joner Oliveira Alves

    2014-10-01

    Full Text Available The increased demand for energy from sugarcane bagasse has made the sugar and alcohol mills search alternatives to reduce maintenance of the boilers, releasing more time to the production. The stainless steel use has become one of the main tools for such reduction. However, specification errors can lead to premature failures. This work reports the factors that led tubes of AISI 409 stainless steel fail after half season when applied in a air preheater of boiler from a sugarcane mill. In such application, the AISI 304 lasts about 15 seasons and the carbon steel about 3. A tube sent by the sugar mill was characterized by wet chemical analysis, optical microscopy and EDS. Results indicated chloride formation on the internal walls of the tube, which combined with the environment, accelerated the corrosion process. The carbon steel showed high lifetime due to a 70% higher thickness. Due to the work condictions is recommended the use of stainless steels with higher corrosion resistance, such as the traditional AISI 304 or the ferritic AISI 444, the last presents better thermal exchange.

  13. Effects of Preheating Temperature,Moisture and Sodium Metabisulfite Content on Property of Maize Flour Dough

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Processing temperature,maze flour particle size,and level of water and sodium metabisulfite were varied during the preparation of maize noodles.Preheated to 90-95 ℃ a mixture of maize flour or meal,water(43%-45% moisture) and salt enabled the preparation of noodles using a pasta extruder.Maize flour with smaller particle size yielded better noodles than did maize meal.The addition of sodium metabisulfite enabled the production of noodles at lower processing temperatures; however,cooking losses increased.Processing maize flour with higher water absorption yielded noodles that required longer cooking time but with decreased losses.The functionalities of starch and protein in raw ingredients and in products were determined.Starch gelatinized and retorgraded during processing maize noodles,as indicated by changes in pasting viscosity curves.Maize proteins contributed to the increased viscosity of dough above 40 ℃.The increased integrity of cooked maize noodles,however,corresponded to the increased amounts of gelatinized and retrograded starch.

  14. Influence of combustion-preheating vitiation on operability of a hypersonic inlet

    Science.gov (United States)

    Liu, K.; Zhu, Y.; Gao, W.; Yang, J.; Jin, Y.; Wu, Y.

    2016-11-01

    Vitiation of the test flow with combustion products is inherent in combustion wind tunnels, and its effect on experimental results needs to be clarified. In this study, the influence of air vitiation on the startability and performance of a hypersonic inlet is investigated through two-dimensional (2D) numerical simulation. The study examines the vitiation effects introduced by carbon dioxide and water vapor, on the basis of maintaining the static pressure, static temperature and Mach number of the incoming flow. The starting Mach number limits of the inlet are estimated, and it is found that both of these vitiation components lower the starting limit of the inlet. This suggests that the experimental results acquired by tests in combustion wind tunnels overestimate the startability of an inlet and, therefore, combustion-preheated facilities may not be completely trusted in this respect. Deviations in the inlet performance caused by the vitiation are also detected. These are nevertheless minor as long as the flow is at the same started or unstarted condition. A further analysis reveals that it is mainly the increase in the heat capacity, and the resulting weaker shock/compression waves and shock-wave/boundary-layer interactions that account for the aforementioned effects.

  15. MINLP model for simultaneous scheduling and retrofit of refinery preheat train

    Directory of Open Access Journals (Sweden)

    Zulkafli N. Izyan, M. Noryani, Abdul H. Dayanasari, M. Shuhaimi

    2014-01-01

    Full Text Available There is greater awareness today on the depleting fossil energy resources and the growing problem of atmospheric pollution. Engineers are developing practical techniques to ensure energy processes are designed and operated efficiently. Inefficient heat exchangers lead to higher fuel demand and higher carbon emission. This paper presents mixed-integer nonlinear programming (MINLP model for simultaneous cleaning and retrofit of crude preheat train (CPT in oil refinery plant. The formulation of the model is generated and coded in General Algebraic Modeling System (GAMS. The model minimizes the cost of energy and the cost of cleaning. The model takes into account the changes in fouling rates throughout time. There are two cases for this study. The cases are online cleaning (Case 1 and simultaneous online cleaning and retrofit (Case 2. The largest energy saving are found in Case 2. The installation of high efficiency heat exchangers improves furnace inlet temperature (FIT from 215oC to 227oC. Furthermore, Case 2 results in the highest percentage of cost saving by about 59%. The payback period for investment in high efficiency heat exchangers is 5 months. Thus, Case 2 is the most cost effective option for reductions of energy consumption in Crude Distillation Unit (CDU.

  16. Effect of substrate preheating temperature and coating thickness on residual stress in plasma sprayed hydroxyapatite coating

    Science.gov (United States)

    Tang, Dapei

    2015-07-01

    A thermal-mechanical coupling model was developed based on thermal-elastic- plastic theory according the special process of plasma spraying Hydroxyapatite (HA) coating upon Ti-6Al-4V substrate. On the one hand, the classical Fourier transient heat conduction equation was modified by introducing the effect item of deformation on temperature, on the other hand, the Johnson-Cook model, suitable for high temperature and high strain rate conditions, was used as constitutive equation after considering temperature softening effect, strain hardening effect and strain rate reinforcement effect. Based on the above coupling model, the residual stress field within the HA coating was simulated by using finite element method (FEM). Meanwhile, the substrate preheating temperature and coating thickness on the influence of residual stress components were calculated, respectively. The failure modes of coating were also preliminary analyzed. In addition, in order to verify the reliability of calculation, the material removal measurement technique was applied to determine the residual stress of HA coating near the interface. Some important conclusions are obtained.

  17. Preheating of the early universe by radiation from high-mass X-ray binaries

    Science.gov (United States)

    Sazonov, S. Yu.; Khabibullin, I. I.

    2017-04-01

    Using a reliablymeasured intrinsic (i.e., corrected for absorption effects) present-day luminosity function of high-mass X-ray binaries (HMXBs) in the 0.25-2 keV energy band per unit star formation rate, we estimate the preheating of the early Universe by soft X-rays from such systems. We find that X-ray irradiation, mainly executed by ultraluminous and supersoft ultraluminous X-ray sources with luminosity L X > 1039 erg s-1, could significantly heat ( T > T CMB, where T CMB is the temperature of the cosmic microwave background) the intergalactic medium by z 10 if the specific X-ray emissivity of the young stellar population in the early Universe was an order of magnitude higher than at the present epoch (which is possible due to the low metallicity of the first galaxies) and the soft X-ray emission from HMXBs did not suffer strong absorption within their galaxies. This makes it possible to observe the 21 cm line of neutral hydrogen in emission from redshifts z < 10.

  18. Performance and emission evaluation of a CI engine fueled with preheated raw rapeseed oil (RRO)-diesel blends

    Energy Technology Data Exchange (ETDEWEB)

    Hazar, Hanbey [Department of Automotive, Faculty of Technical Education, Firat University, Elazig 23119 (Turkey); Aydin, Hueseyin [Department of Automotive, Faculty of Technical Education, Batman University, Batman 72060 (Turkey)

    2010-03-15

    Many studies are still being carried out to find out surplus information about how vegetable based oils can efficiently be used in compression ignition engines. Raw rapeseed oil (RRO) was used as blended with diesel fuel (DF) by 50% oil-50% diesel fuel in volume (O50) also as blended with diesel fuel by 20% oil-80% diesel fuel in volume (O20). The test fuels were used in a single cylinder, four stroke, naturally aspirated, direct injection compression ignition engine. The effects of fuel preheating to 100 C on the engine performance and emission characteristics of a CI engine fueled with rapeseed oil diesel blends were clarified. Results showed that preheating of RRO was lowered RRO's viscosity and provided smooth fuel flow Heating is necessary for smooth flow and to avoid fuel filter clogging. It can be achieved by heating RRO to 100 C. It can also be concluded that preheating of the fuel have some positive effects on engine performance and emissions when operating with vegetable oil. (author)

  19. Formation of the preheated zone ahead of a propagating flame and the mechanism underlying the deflagration-to-detonation transition

    Science.gov (United States)

    Liberman, M. A.; Kuznetsov, M.; Ivanov, A.; Matsukov, I.

    2009-01-01

    The Letter presents analytical, numerical and experimental studies of the mechanism underlying the deflagration-to-detonation transition (DDT). Insight into how, when, and where DDT occurs is obtained by analyzing analytically and by means of multidimensional numerical simulations dynamics of a flame accelerating in a tube with no-slip walls. It is shown that the deflagration-to-detonation transition exhibits three separate stages of evolution corroborating majority experimental observations. During the first stage flame accelerates and generates shocks far ahead of the flame front. During the second stage the flame slows down, shocks are formed in the immediate proximity of the flame front and the preheated zone ahead of the flame front is created. The third stage is self-restructuring of the steep temperature profile within the flame, formation of a reactivity gradient and the actual formation of the detonation wave itself. The mechanism for the detonation wave formation, given an appropriate formation of the preheated zone, seems to be universal and involves a reactivity gradient formed from the initially steep flame temperature profile in the presence of the preheated zone. The developed theory and numerical simulations are found to be well consistent with extensive experiments of the DDT in hydrogen-oxygen and ethylene-oxygen mixtures in tubes with smooth and rough walls.

  20. Hard x-ray (>100 keV) imager to measure hot electron preheat for indirectly driven capsule implosions on the NIF.

    Science.gov (United States)

    Döppner, T; Dewald, E L; Divol, L; Thomas, C A; Burns, S; Celliers, P M; Izumi, N; Kline, J L; LaCaille, G; McNaney, J M; Prasad, R R; Robey, H F; Glenzer, S H; Landen, O L

    2012-10-01

    We have fielded a hard x-ray (>100 keV) imager with high aspect ratio pinholes to measure the spatially resolved bremsstrahlung emission from energetic electrons slowing in a plastic ablator shell during indirectly driven implosions at the National Ignition Facility. These electrons are generated in laser plasma interactions and are a source of preheat to the deuterium-tritium fuel. First measurements show that hot electron preheat does not limit obtaining the fuel areal densities required for ignition and burn.

  1. Anger perceptually and conceptually narrows cognitive scope.

    Science.gov (United States)

    Gable, Philip A; Poole, Bryan D; Harmon-Jones, Eddie

    2015-07-01

    For the last 50 years, research investigating the effect of emotions on scope of cognitive processing was based on models proposing that affective valence determined cognitive scope. More recently, our motivational intensity model suggests that this past work had confounded valence with motivational intensity. Research derived from this model supports the idea that motivational intensity, rather than affective valence, explains much of the variance emotions have on cognitive scope. However, the motivational intensity model is limited in that the empirical work has examined only positive affects high in approach and negative affects high in avoidance motivation. Thus, perhaps only approach-positive and avoidance-negative states narrow cognitive scope. The present research was designed to clarify these conceptual issues by examining the effect of anger, a negatively valenced approach-motivated state, on cognitive scope. Results revealed that anger narrowed attentional scope relative to a neutral state and that attentional narrowing to anger was similar to the attentional narrowing caused by high approach-motivated positive affects (Study 1). This narrowing of attention was related to trait approach motivation (Studies 2 and Study 3). Anger also narrowed conceptual cognitive categorization (Study 4). Narrowing of categorization related to participants' approach motivation toward anger stimuli. Together, these results suggest that anger, an approach-motivated negative affect, narrows perceptual and conceptual cognitive scope. More broadly, these results support the conceptual model that motivational intensity per se, rather than approach-positive and avoidance-negative states, causes a narrowing of cognitive scope.

  2. Effect of preheating of low shrinking resin composite on intrapulpal temperature and microtensile bond strength to dentin

    Science.gov (United States)

    El-Deeb, Heba A.; Abd El-Aziz, Sara; Mobarak, Enas H.

    2014-01-01

    The effect of preheating of the silorane-based resin composite on intrapulpal temperature (IPT) and dentin microtensile bond strength (μTBS) was evaluated. For the IPT, teeth (n = 15) were sectioned to obtain discs of 0.5 mm thickness (2 discs/tooth). The discs were divided into three groups (n = 10/group) according to the temperature of the Filtek LS™ silorane-based resin composite during its placement, either at room temperature (23 ± 1 °C) or preheated to 54 °C or 68 °C using a commercial Calset™ device. Discs were subjected to a simulated intrapulpal pressure (IPP) and placed inside a specially constructed incubator adjusted at 37 °C. IPT was measured before, during and after placement and curing of the resin composite using K-type thermocouple. For μTBS testing, flat occlusal middentin surfaces (n = 24) were obtained. P90 System Adhesive was applied according to manufacturer’s instructions then Filtek LS was placed at the tested temperatures (n = 6). Restorative procedures were done while the specimens were connected to IPP simulation. IPP was maintained and the specimens were immersed in artificial saliva at 37 °C for 24 h before testing. Each specimen was sectioned into sticks (0.9 ± 0.01 mm2). The sticks (24/group) were subjected to μTBS test and their modes of failure were determined using scanning electron microscope (SEM). For both preheated groups, IPT increased equally by 1.5–2 °C upon application of the composite. After light curing, IPT increased by 4–5 °C in all tested groups. Nevertheless, the IPT of the preheated groups required a longer time to return to the baseline temperature. One-way ANOVA revealed no significant difference between the μTBS values of all groups. SEM revealed predominately mixed mode of failure. Preheating of silorane-based resin composite increased the IPT but not to the critical level and had no effect on dentin μTBS. PMID:26257945

  3. Effect of preheating of low shrinking resin composite on intrapulpal temperature and microtensile bond strength to dent

    Directory of Open Access Journals (Sweden)

    Heba A. El-Deeb

    2015-05-01

    Full Text Available The effect of preheating of the silorane-based resin composite on intrapulpal temperature (IPT and dentin microtensile bond strength (μTBS was evaluated. For the IPT, teeth (n = 15 were sectioned to obtain discs of 0.5 mm thickness (2 discs/tooth. The discs were divided into three groups (n = 10/group according to the temperature of the Filtek LS™ silorane-based resin composite during its placement, either at room temperature (23 ± 1 °C or preheated to 54 °C or 68 °C using a commercial Calset™ device. Discs were subjected to a simulated intrapulpal pressure (IPP and placed inside a specially constructed incubator adjusted at 37 °C. IPT was measured before, during and after placement and curing of the resin composite using K-type thermocouple. For μTBS testing, flat occlusal middentin surfaces (n = 24 were obtained. P90 System Adhesive was applied according to manufacturer’s instructions then Filtek LS was placed at the tested temperatures (n = 6. Restorative procedures were done while the specimens were connected to IPP simulation. IPP was maintained and the specimens were immersed in artificial saliva at 37 °C for 24 h before testing. Each specimen was sectioned into sticks (0.9 ± 0.01 mm2. The sticks (24/group were subjected to μTBS test and their modes of failure were determined using scanning electron microscope (SEM. For both preheated groups, IPT increased equally by 1.5–2 °C upon application of the composite. After light curing, IPT increased by 4–5 °C in all tested groups. Nevertheless, the IPT of the preheated groups required a longer time to return to the baseline temperature. One-way ANOVA revealed no significant difference between the μTBS values of all groups. SEM revealed predominately mixed mode of failure. Preheating of silorane-based resin composite increased the IPT but not to the critical level and had no effect on dentin μTBS.

  4. Effect of preheating of low shrinking resin composite on intrapulpal temperature and microtensile bond strength to dentin.

    Science.gov (United States)

    El-Deeb, Heba A; Abd El-Aziz, Sara; Mobarak, Enas H

    2015-05-01

    The effect of preheating of the silorane-based resin composite on intrapulpal temperature (IPT) and dentin microtensile bond strength (μTBS) was evaluated. For the IPT, teeth (n = 15) were sectioned to obtain discs of 0.5 mm thickness (2 discs/tooth). The discs were divided into three groups (n = 10/group) according to the temperature of the Filtek LS™ silorane-based resin composite during its placement, either at room temperature (23 ± 1 °C) or preheated to 54 °C or 68 °C using a commercial Calset™ device. Discs were subjected to a simulated intrapulpal pressure (IPP) and placed inside a specially constructed incubator adjusted at 37 °C. IPT was measured before, during and after placement and curing of the resin composite using K-type thermocouple. For μTBS testing, flat occlusal middentin surfaces (n = 24) were obtained. P90 System Adhesive was applied according to manufacturer's instructions then Filtek LS was placed at the tested temperatures (n = 6). Restorative procedures were done while the specimens were connected to IPP simulation. IPP was maintained and the specimens were immersed in artificial saliva at 37 °C for 24 h before testing. Each specimen was sectioned into sticks (0.9 ± 0.01 mm(2)). The sticks (24/group) were subjected to μTBS test and their modes of failure were determined using scanning electron microscope (SEM). For both preheated groups, IPT increased equally by 1.5-2 °C upon application of the composite. After light curing, IPT increased by 4-5 °C in all tested groups. Nevertheless, the IPT of the preheated groups required a longer time to return to the baseline temperature. One-way ANOVA revealed no significant difference between the μTBS values of all groups. SEM revealed predominately mixed mode of failure. Preheating of silorane-based resin composite increased the IPT but not to the critical level and had no effect on dentin μTBS.

  5. A comparison of winter pre-heating requirements for natural displacement and natural mixing ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Woods, Andrew W. [BP Institute, University of Cambridge, Cambridge, CB3 OEZ (United Kingdom); Fitzgerald, Shaun; Livermore, Stephen [E-Stack Ltd., St Johns Innovation Centre, Cambridge (United Kingdom)

    2009-12-15

    In winter, natural ventilation can be achieved either through mixing ventilation or upward displacement ventilation (P.F. Linden, The fluid mechanics of natural ventilation, Annual Review of Fluid Mechanics 31 (1999) pp. 201-238). We show there is a significant energy saving possible by using mixing ventilation, in the case that the internal heat gains are significant, and illustrate these savings using an idealized model, which predicts that with internal heat gains of order 0.1 kW per person, mixing ventilation uses of a fraction of order 0.2-0.4 of the heat load of displacement ventilation assuming a well-insulated building. We then describe a strategy for such mixing natural ventilation in an atrium style building in which the rooms surrounding the atrium are able to vent directly to the exterior and also through the atrium to the exterior. The results are motivated by the desire to reduce the energy burden in large public buildings such as hospitals, schools or office buildings centred on atria. We illustrate a strategy for the natural mixing ventilation in order that the rooms surrounding the atrium receive both pre-heated but also sufficiently fresh air, while the central atrium zone remains warm. We test the principles with some laboratory experiments in which a model air chamber is ventilated using both mixing and displacement ventilation, and compare the energy loads in each case. We conclude with a discussion of the potential applications of the approach within the context of open plan atria type office buildings. (author)

  6. Equation of state of Mo from shock compression experiments on preheated samples

    Science.gov (United States)

    Fat'yanov, O. V.; Asimow, P. D.

    2017-03-01

    We present a reanalysis of reported Hugoniot data for Mo, including both experiments shocked from ambient temperature (T) and those preheated to 1673 K, using the most general methods of least-squares fitting to constrain the Grüneisen model. This updated Mie-Grüneisen equation of state (EOS) is used to construct a family of maximum likelihood Hugoniots of Mo from initial temperatures of 298 to 2350 K and a parameterization valid over this range. We adopted a single linear function at each initial temperature over the entire range of particle velocities considered. Total uncertainties of all the EOS parameters and correlation coefficients for these uncertainties are given. The improved predictive capabilities of our EOS for Mo are confirmed by (1) better agreement between calculated bulk sound speeds and published measurements along the principal Hugoniot, (2) good agreement between our Grüneisen data and three reported high-pressure γ ( V ) functions obtained from shock-compression of porous samples, and (3) very good agreement between our 1 bar Grüneisen values and γ ( T ) at ambient pressure recalculated from reported experimental data on the adiabatic bulk modulus K s ( T ) . Our analysis shows that an EOS constructed from shock compression data allows a much more accurate prediction of γ ( T ) values at 1 bar than those based on static compression measurements or first-principles calculations. Published calibrations of the Mie-Grüneisen EOS for Mo using static compression measurements only do not reproduce even low-pressure asymptotic values of γ ( T ) at 1 bar, where the most accurate experimental data are available.

  7. Destruction of DDT wastes in two preheater/precalciner cement kilns in China.

    Science.gov (United States)

    Yan, Dahai; Peng, Zheng; Karstensen, Kåre Helge; Ding, Qiong; Wang, Kaixiang; Wang, Zuguang

    2014-04-01

    The destruction of DDT formulations and DDT contaminated soil was conducted by feeding wastes into the flue gas chamber at the kiln inlet of two different preheater/precalciner cement kilns in China. The concentration of DDT, PCDD/PCDFs and HCB were measured in the flue gas of the main stack, in the solid material under baseline conditions and when feeding DDT-wastes. The destruction efficiency and the destruction and removal efficiency for DDT were in the range of 99.9335%-99.9998% and 99.9984%-99.9999%, respectively. The emissions of PCDD/PCDFs and HCB in the flue gas varied in the range of 0.0019-0.0171 ng I-TEQ/Nm(3) and 0.0064-0.0404 μg/Nm(3), respectively. The emission factor for PCDD/PCDF and HCB varied from 0.0137 to 0.0281 μg/ton and from 17.32 to 109.34 μg/ton of clinker, respectively. The concentration of PCDD/PCDFs and HCB in solid samples decreased as follows: cement kiln dust, 4.1-5 ng I-TEQ/kg and 0.70-0.71 μg/kg, respectively; >raw meal, 0.82-0.97 ng I-TEQ/kg and 0.18 μg/kg, respectively; >cement clinker, 0.09-0.22 ng I-TEQ/kg and 0.14-0.18 μg/kg, respectively. This study indicates that the feeding of DDT and POPs-wastes to the lower temperature part of a cement kiln system possibly to create a buildup of trace not-destroyed compounds in the system and might cause emissions; the technical feasibility and the environmental acceptability of this practice need to be investigated thoroughly.

  8. Recycling ash into the first stage of cyclone pre-heater of cement kiln.

    Science.gov (United States)

    Zhan, Ming-Xiu; Fu, Jian-Ying; Havukainen, Jouni; Chen, Tong; Li, Xiao-Dong; Yan, Jian-Hua; Buekens, Alfons

    2016-10-01

    Fly ash collected from the bag filter could be recycled into the first stage of the cyclone pre-heater of the cement kiln, resulting in the possible enrichment of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). In this study, soxhlet fly ash (SFA) and raw meal (RM) were selected as the basis for the PCDD/F formation experiments. The levels of 2,3,7,8-PCDD/Fs formed on the SFA and RM were observed to be 2550pg/g (157pg I-TEQ/g) and 1142pg/g (55pg I-TEQ/g), respectively. While less 2,3,7,8-PCDD/Fs was detected when SFA was mixed with RM, suggesting that recycling cement kiln ash would not largely increase the concentration of PCDD/Fs in flue gas. Furthermore, the possible influencing factors on the PCDD/F formation were also investigated. The formation of 2,3,7,8-PCDD/Fs was up to 10,871pg/g (380pg I-TEQ/g) with the adding of CuCl2, which was much higher than the results of CuO and activated carbon. Most importantly, the homologue, congener and gas/particle distribution of PCDD/Fs indicated that de novo synthesis was the dominant PCDD/F formation pathway for SFA. Lastly, principal component analysis (PCA) was also conducted to identify the relationship between the compositions of reactant and the properties of PCDD/Fs produced.

  9. Effect of Pre-heating on Microtensile Bond Strength of Composite Resin to Dentin.

    Directory of Open Access Journals (Sweden)

    Abdolrahim Davari

    2014-10-01

    Full Text Available Direct composite resin restorations are widely used and the impact of different storage temperatures on composites is not well understood. The purpose of this study was to evaluate the microtensile bond strength of composite to dentin after different pre-curing temperatures.Occlusal surfaces of 44 human molars were ground with diamond burs under water coolant and polished with 600 grit silicon carbide papers to obtain flat dentin surfaces. The dentin was etched with 37% phosphoric acid and bonded with Adper Single Bond 2 according to the manufacturer's instructions. The specimens were randomly divided into two groups (n=22 according to the composite resin applied: FiltekP60 and Filtek Z250. Each group included three subgroups of composite resin pre-curing temperatures (4°C, 23°C and 37°C. Composite resins were applied to the dentin surfaces in a plastic mold (8mm in diameter and 4mm in length incrementally and cured. Twenty-two composite-to-dentin hour-glass sticks with one mm(2 cross-sectional area per group were prepared. Microtensile bond strength measurements were made using a universal testing machine at a crosshead speed of one mm/min. For statistical analysis, t-test, one-way and two-way ANOVA were used. The level of significance was set at P<0.05.Filtek P60 pre-heated at 37ºC had significantly higher microtensile bond strength than Filtek Z250 under the same condition. The microtensile bond strengths were not significantly different at 4ºC, 23ºC and 37ºC subgroups of each composite resin group.Filtek P60 and Filtek Z250 did not have significantly different microtensile bond strengths at 4ºC and 23ºC but Filtek P60 had significantly higher microtensile bond strength at 37 ºC. Composite and temperature interactions had significant effects on the bond strength.

  10. Effects of preheating and precooling on the hardness and shrinkage of a composite resin cured with QTH and LED.

    Science.gov (United States)

    Osternack, F H; Caldas, D B M; Almeida, J B; Souza, E M; Mazur, R F

    2013-01-01

    The aim of this study was to evaluate in vitro the hardness and shrinkage of a pre-cooled or preheated hybrid composite resin cured by a quartz-tungsten-halogen light (QTH) and light-emitting diode (LED) curing units. The temperature on the tip of the devices was also investigated. Specimens of Charisma resin composite were produced with a metal mold kept under 37°C. The syringes were submitted to 4°C, 23°C, and 60°C (n=20) before light-curing, which was carried out with the Optilux 501 VCL and Elipar FreeLight 2 units for 20 seconds. The specimens were kept under 37°C in a high humidity condition and darkness for 48 hours. The Knoop hardness test was carried out with a 50 gram-force (gf) load for 10 seconds, and the measurement of the shrinkage gap was carried out using an optical microscope. The data were subjected to analysis of variance and the Games-Howell test (α=0.05). The mean hardness of the groups were similar, irrespective of the temperatures (p>0.05). For 4°C and 60°C, the top surface light-cured by LED presented significantly reduced shrinkage when compared with the bottom and to both surfaces cured by QTH (phardness was not affected by pre-cooling or preheating. However, polymerization shrinkage was slightly affected by different pre-polymerization temperatures. The QTH-curing generated greater shrinkage than LED-curing only when the composite was preheated. Different temperatures did not affect the composite hardness and shrinkage when cured by a LED curing unit.

  11. Effects of target pre-heating and expansion on terahertz radiation production from intense laser-solid interactions

    Institute of Scientific and Technical Information of China (English)

    X.H.Yuan; Y.Fang; D.C.Carroll; D.A.MacLellan; F.Du; N.Booth; M.Burza; M.Chen; R.J.Gray; Y.F.Jin; Y.T.Li; Y.Liu; D.Neely; H.Powell; G.Scott; C.-G.Wahlstrm; J.Zhang; P.McKenna; Z.M.Sheng

    2014-01-01

    The first experimental measurements of intense(~7 × 1019 W cm-2) laser-driven terahertz(THz) radiation from a solid target which is preheated by an intense pulse of laser-accelerated protons is reported. The total energy of the THz radiation is found to decrease by approximately a factor of 2 compared to a cold target reference. This is attributed to an increase in the scale length of the preformed plasma, driven by proton heating, at the front surface of the target,where the THz radiation is generated. The results show the importance of controlling the preplasma scale length for THz production.

  12. A Generalized and Simple Numerical Model to Compute the Feed Water Preheating System for Steam Power Plants

    Directory of Open Access Journals (Sweden)

    Ioana Opriș

    2017-02-01

    Full Text Available A general and simple numerical model is presented to calculate the uncontrolled steam flows extracted from a turbine to preheat the feed-water of a steam generator. For a user-defined technological scheme, a set of clear rules is given to complete the elements of the augmented matrix of the linear system that solves the problem. The model avoids writing of the heat balance equations for each heat exchanger. The steam extractions to the heaters are determined as related to the flow rate at the condenser. A numerical example is given to show the results.

  13. A Narrow View of Reading Promotes Comprehension

    National Research Council Canada - National Science Library

    Alan G Kamhi

    2007-01-01

      In sum, embracing the narrow view of reading will promote differentiated assessment of reading and content-specific knowledge that will not only eliminate the reading crisis, but also focus attention...

  14. Device Physics of Narrow Gap Semiconductors

    CERN Document Server

    Chu, Junhao

    2010-01-01

    Narrow gap semiconductors obey the general rules of semiconductor science, but often exhibit extreme features of these rules because of the same properties that produce their narrow gaps. Consequently these materials provide sensitive tests of theory, and the opportunity for the design of innovative devices. Narrow gap semiconductors are the most important materials for the preparation of advanced modern infrared systems. Device Physics of Narrow Gap Semiconductors offers descriptions of the materials science and device physics of these unique materials. Topics covered include impurities and defects, recombination mechanisms, surface and interface properties, and the properties of low dimensional systems for infrared applications. This book will help readers to understand not only the semiconductor physics and materials science, but also how they relate to advanced opto-electronic devices. The last chapter applies the understanding of device physics to photoconductive detectors, photovoltaic infrared detector...

  15. Narrow deeply bound K- atomic states

    Science.gov (United States)

    Friedman, E.; Gal, A.

    1999-07-01

    Using optical potentials fitted to a comprehensive set of strong interaction level shifts and widths in K- atoms, we predict that the K- atomic levels which are inaccessible in the atomic cascade process are generally narrow, spanning a range of widths about 50-1500 keV over the entire periodic table. The mechanism for this narrowing is different from the mechanism for narrowing of pionic atom levels. Examples of such `deeply bound' K- atomic states are given, showing that in many cases these states should be reasonably well resolved. Several reactions which could be used to form these `deeply bound' states are mentioned. Narrow deeply bound states are expected also in overlinep atoms.

  16. Effect of preheating on the damage to tungsten targets after repetitive ITER ELM-like heat loads

    Energy Technology Data Exchange (ETDEWEB)

    Makhlay, V A [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Bandura, A N [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Byrka, O V [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Garkusha, I E [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Chebotarev, V V [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Tereshin, V I [Institute of Plasma Physics of the NSC KIPT 1, Akademicheskaya, 61108 Kharkov (Ukraine); Landman, I [Forschungszentrum Karlsruhe, IHM, 76021 Karlsruhe (Germany)

    2007-03-15

    The behaviour of a preheated tungsten target under repetitive pulsed plasma impacts of the energy density 0.75 MJ m{sup -2} with the pulse duration of 0.25 ms was studied with the quasi-stationary plasma accelerator (QSPA) Kh-50. Two identical samples of pure sintered tungsten have been exposed to numbers of pulses exceeding 100. One sample was maintained at room temperature and the other sample preheated at 650 deg. C. The experiments demonstrated that on the cold surface some macro-cracks dominate, but on the hot surface they do not develop. However, in both cases some fine meshes of micro-cracks are observed. With increasing the number of exposures, the width of the micro-cracks gradually increases, achieving 0.8-1.5 {mu}m after 100 pulses. In addition, the SEM shows some cellular structure with the cell sizes about 0.3 {mu}m, and after large numbers of exposures some blisters of sizes up to 100-150 {mu}m appear.

  17. Influence of pre-heat treatment and different light-curing units on Vickers hardness of a microhybrid composite resin

    Science.gov (United States)

    Saade, E. G.; Bandeca, M. C.; Rastelli, A. N. S.; Bagnato, V. S.; Porto-Neto, S. T.

    2009-06-01

    The aim of this study was to evaluate the hardness of a dental composite resin submitted to temperature changes before photo-activation with two light-curing unite (LCUs). Five samples (4 mm in diameter and 2 mm in thickness) for each group were made with pre-cure temperatures of 37, 54, and 60°C. The samples were photo-activated with a conventional quartz-tungsten-halogen (QTH) and blue LED LCUs during 40 s. The hardness Vickers test (VHN) was performed on the top and bottom surfaces of the samples. According to the interaction between light-curing unit and different pre-heating temperatures of composite resin, only the light-curing unit provided influences on the mean values of initial Vickers hardness. The light-curing unit based on blue LED showed hardness mean values more homogeneous between the top and bottom surfaces. The hardness mean values were not statistically significant difference for the pre-cure temperature used. According to these results, the pre-heating of the composite resin provide no influence on Vickers hardness mean values, however the blue LED showed a cure more homogeneous than QTH LCU.

  18. 预热工艺对钢化玻璃性能的影响%Influence of Preheating Process on Tempered Glass Properties

    Institute of Scientific and Technical Information of China (English)

    赵旭东; 张晓娟

    2015-01-01

    Preheat under different conditions (other things being equal), double chamber strong convection horizontal tempering furnace was carried out on 6mm clear glass tempered processing, analyzed the effects of preheating parameters on the performance of the tempered glass, and the results are discussed.%在不同的预热条件(其它条件相同)下,利用双室强对流水平钢化炉对6 mm白玻进行钢化处理,分析了预热参数对钢化玻璃性能的影响,并对结果进行了讨论.

  19. RESPONSE OF NONLINEAR OSCILLATOR UNDER NARROW-BAND RANDOM EXCITATION

    Institute of Scientific and Technical Information of China (English)

    戎海武; 王向东; 孟光; 徐伟; 方同

    2003-01-01

    The principal resonance of Duffing oscillator to narrow-band random parametricexcitation was investigated. The method of multiple scales was used to determine theequations of modulation of amplitude and phase. The behavior, stability and bifurcation ofsteady state response were studied by means of qualitative analyses. The effects of damping,detuning, bandwidth and magnitudes of deterministic and random excitations wereanalyzed. The theoretical analyses were verified by numerical results. Theoretical analysesand numerical simulations show that when the intensity of the random excitation increases,the nontrivial steady state solution may change from a limit cycle to a diffused limit cycle.Under some conditions the system may have two ,steady state solutions.

  20. Efficient, Narrow-Pass-Band Optical Filters

    Science.gov (United States)

    Sandford, Stephen P.

    1996-01-01

    Optical filters with both narrow pass bands and high efficiencies fabricated to design specifications. Offer tremendous improvements in performance for number of optical (including infrared) systems. In fiber-optic and free-space communication systems, precise frequency discrimination afforded by narrow pass bands of filters provide higher channel capacities. In active and passive remote sensors like lidar and gas-filter-correlation radiometers, increased efficiencies afforded by filters enhance detection of small signals against large background noise. In addition, sizes, weights, and power requirements of many optical and infrared systems reduced by taking advantage of gains in signal-to-noise ratios delivered by filters.

  1. On Narrow Nucleon Excitation N*(1685)

    CERN Document Server

    Kuznetsov, V; Thuermann, M

    2011-01-01

    We collected notes and simple estimates about putative narrow nucleon N*(1685) - the candidate for the non-strange member of the exotic anti-decuplet of baryons. In particular, we consider the recent high precision data on eta photoproduction off free proton obtained by the Crystal Ball Collaboration at MAMI. We show that it is difficult to describe peculiarities of these new data in the invariant energy interval of W ~ 1650-1750 MeV in terms of known wide resonances. Using very simple estimates, we show that the data may indicate an existence of a narrow N*(1685) with small photocoupling to the proton.

  2. Study of sensitivity change of OSL signals from quartz and feldspars as a function of preheat temperature

    DEFF Research Database (Denmark)

    Jungner, H.; Bøtter-Jensen, L.

    1994-01-01

    Optically stimulated luminescence (OSL) signals from feldspar and quartz samples were studied using infrared (860 nm) and green light (420-575 nm) stimulation. A serious problem connected with the regeneration technique used for dating is associated with a change of OSL sensitivity to radiation...... in the couse of the measurement process. A typical effect seen is a large increase of the apparent strength of our beta source when calibrated against a gamma source. If the regeneration procedure is used, it is shown that the sensitivity increases up to similar to 50% during the measurement process...... and as a result, the equivalent dose (ED) would be underestimated. A study of sensitivity changes in feldspars and quartz was carried out with emphasis on the effect of preheat and annealing on the OSL signal. Measurement results obtained are presented, and possible elimination of errors in dating caused...

  3. Effects of preheating of crude palm oil (CPO) on injection system, performance and emission of a diesel engine

    Energy Technology Data Exchange (ETDEWEB)

    Bari, S.; Lim, T.H.; Yu, C.W. [Universiti Sains Malaysia, School of Mechanical Engineering, Penang (Malaysia)

    2002-11-01

    Crude palm oil (CPO) is one of the vegetable oils that have potential for use as fuels for diesel engines. CPO is renewable, and is safe and easy to handle. However, at room temperature (30-32 deg C) CPO has a viscosity about 10 times higher than that of diesel. To lower CPO's viscosity to the level of diesel's viscosity, a heating temperature of at least 92 deg C is needed. At this temperature, there is a concern that the close-fitting parts of the injection system might be affected. This study focused on finding out the effects of preheating of fuel on the injection system utilising a modified method of friction test, which involves injecting fuel outside the combustion chamber during motoring. Results show that preheating of CPO lowered CPO's viscosity and provided smooth fuel flow, but did not affect the injection system, even heating up to 100 deg C. Nevertheless, heating up to such a high temperature offered no benefits in terms of engine performance. However, heating is necessary for smooth flow and to avoid fuel filter clogging. Both can be achieved by heating CPO to 60 deg C. Combustion analyses comparisons between CPO and diesel found that CPO produced a higher peak pressure of 6%, a shorter ignition delay of 2.6 deg, a lower maximum heat release rate and a longer combustion period. Over the entire load range, CPO combustion produced average CO and NO emissions that were 9.2 and 29.3% higher, respectively, compared with those from diesel combustion. (Author)

  4. Narrow-Band Applications of Communications Satellites.

    Science.gov (United States)

    Cowlan, Bert; Horowitz, Andrew

    This paper attempts to describe the advantages of "narrow-band" applications of communications satellites for education. It begins by discussing the general controversy surrounding the use of satellites in education, by placing the concern within the larger context of the general debate over the uses of new technologies in education, and by…

  5. Narrow vision after view-broadening travel.

    Science.gov (United States)

    Melo, Mariana de Mendonça; Ciriano, Jose P Martinez; van Genderen, Perry J J

    2008-01-01

    Loss of vision is a threatening presentation of disease. We describe a case of acute idiopathic blind spot enlargement in a 26-year-old male traveler who presented with narrow vision after a journey to Indonesia. Although the patient used mefloquine at time of presentation, we were unable to retrieve sound data incriminating mefloquine in this rare eye disorder.

  6. Narrow thermal hysteresis of NiTi shape memory alloy thin films with submicrometer thickness

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Huilong; Hamilton, Reginald F., E-mail: rfhamilton@psu.edu; Horn, Mark W. [Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2016-09-15

    NiTi shape memory alloy (SMA) thin films were fabricated using biased target ion beam deposition (BTIBD), which is a new technique for fabricating submicrometer-thick SMA thin films, and the capacity to exhibit shape memory behavior was investigated. The thermally induced shape memory effect (SME) was studied using the wafer curvature method to report the stress-temperature response. The films exhibited the SME in a temperature range above room temperature and a narrow thermal hysteresis with respect to previous reports. To confirm the underlying phase transformation, in situ x-ray diffraction was carried out in the corresponding phase transformation temperature range. The B2 to R-phase martensitic transformation occurs, and the R-phase transformation is stable with respect to the expected conversion to the B19′ martensite phase. The narrow hysteresis and stable R-phase are rationalized in terms of the unique properties of the BTIBD technique.

  7. Quantum Oscillation in Narrow-Gap Topological Insulators.

    Science.gov (United States)

    Zhang, Long; Song, Xue-Yang; Wang, Fa

    2016-01-29

    The canonical understanding of quantum oscillation in metals is challenged by the observation of the de Haas-van Alphen effect in an insulator, SmB_{6} [Tan et al, Science 349, 287 (2015)]. Based on a two-band model with inverted band structure, we show that the periodically narrowing hybridization gap in magnetic fields can induce the oscillation of low-energy density of states in the bulk, which is observable provided that the activation energy is small and comparable to the Landau level spacing. Its temperature dependence strongly deviates from the Lifshitz-Kosevich theory. The nontrivial band topology manifests itself as a nonzero Berry phase in the oscillation pattern, which crosses over to a trivial Berry phase by increasing the temperature or the magnetic field. Further predictions to experiments are also proposed.

  8. Spectral narrowing of a 980 nm tapered diode laser bar

    DEFF Research Database (Denmark)

    Vijayakumar, Deepak; Jensen, Ole Bjarlin; Lucas Leclin, Gaëlle

    2011-01-01

    High power diode laser bars are interesting in many applications such as solid state laser pumping, material processing, laser trapping, laser cooling and second harmonic generation. Often, the free running laser bars emit a broad spectrum of the order of several nanometres which limit their scope...... in wavelength specific applications and hence, it is vital to stabilize the emission spectrum of these devices. In our experiment, we describe the wavelength narrowing of a 12 element 980 nm tapered diode laser bar using a simple Littman configuration. The tapered laser bar which suffered from a big smile has...... been "smile corrected" using individual phase masks for each emitter. The external cavity consists of the laser bar, both fast and slow axis micro collimators, smile correcting phase mask, 6.5x beam expanding lens combination, a 1200 lines/mm reflecting grating with 85% efficiency in the first order...

  9. Powerful narrow linewidth random fiber laser

    Science.gov (United States)

    Ye, Jun; Xu, Jiangming; Zhang, Hanwei; Zhou, Pu

    2017-03-01

    In this paper, we demonstrate a narrow linewidth random fiber laser, which employs a tunable pump laser to select the operating wavelength for efficiency optimization, a narrow-band fiber Bragg grating (FBG) and a section of single mode fiber to construct a half-open cavity, and a circulator to separate pump light input and random lasing output. Spectral linewidth down to 42.31 GHz is achieved through filtering by the FBG. When 8.97 W pump light centered at the optimized wavelength 1036.5 nm is launched into the half-open cavity, 1081.4 nm random lasing with the maximum output power of 2.15 W is achieved, which is more powerful than the previous reported results.

  10. Exciton absorption in narrow armchair graphene nanoribbons

    Science.gov (United States)

    Monozon, B. S.; Schmelcher, P.

    2016-11-01

    We develop an analytical approach to the exciton optical absorption for narrow gap armchair graphene nanoribbons (AGNR). We focus on the regime of dominant size quantization in combination with the attractive electron-hole interaction. An adiabatic separation of slow and fast motions leads via the two-body Dirac equation to the isolated and coupled subband approximations. Discrete and continuous exciton states are in general coupled and form quasi-Rydberg series of purely discrete and resonance type character. The corresponding oscillator strengths and widths are derived. We show that the exciton peaks are blue-shifted, become broader and increase in magnitude upon narrowing the ribbon. At the edge of a subband the singularity related to the 1D density of states is transformed into finite absorption via the presence of the exciton. Our analytical results are in good agreement with those obtained by other methods including numerical approaches. Estimates of the expected experimental values are provided for realistic AGNR.

  11. Narrow optical filtering with plasmonic nanoshells

    CERN Document Server

    Martynov, Y B; Tanachev, I A; Gladyshev, P P

    2011-01-01

    Narrow optical band pass filters are widely used in systems with optical processing of information, color displays development and optical computers. We show that such ultra filters can be created by means of nanoparticles which consist of a dielectric sphere and a metallic shell. The components can be adjusted such that there is a remarkable transparency at the desired wavelength range, while a strong absorption takes place outside of this region.

  12. Code optimizations for narrow bitwidth architectures

    OpenAIRE

    Bhagat, Indu

    2012-01-01

    This thesis takes a HW/SW collaborative approach to tackle the problem of computational inefficiency in a holistic manner. The hardware is redesigned by restraining the datapath to merely 16-bit datawidth (integer datapath only) to provide an extremely simple, low-cost, low-complexity execution core which is best at executing the most common case efficiently. This redesign, referred to as the Narrow Bitwidth Architecture, is unique in that although the datapath is squeezed to 16-bits...

  13. Band Gap Narrowing in Heavily Doped Silicon.

    Science.gov (United States)

    Gupta, Tapan Kumar

    Two analytic models for transport and band gap narrowing in heavily doped (N_{rm D} > 10^{20} cm^ {-3}) silicon have been set up and verified through measurements on n^{+} -p junction devices. The first model is based on calculation of the ratio of the charge present in the emitter of the n^{+} region of the junction to that of the charge present in the absence of band gap shrinkage. Fermi-Dirac statistics are employed and are found to have a significant effect at this doping level. The second model is based on current transport of minority carriers in the n^{+} region. In this model only two parameters need to be known, the diffusion coefficient and the diffusion length for minority carriers, to calculate the band gap narrowing. An empirical relation between band gap narrowing and donor concentration has also been established based on experimental values of diffusion coefficient and mobility. These models have been verified by several different experimental techniques including surface photovoltage, open circuit voltage decay, photoconductivity decay and modulation reflection spectroscopy. The results indicate that, in the impurity range above about 10^{20} cm^{-3}, Fermi-Dirac statistics must be invoked in order to achieve a satisfactory fit with experimental data.

  14. 预热工艺对钢化玻璃性能的影响%Influence of Preheating Process on the Properties of Tempered Glass

    Institute of Scientific and Technical Information of China (English)

    赵旭东

    2015-01-01

    6mm clear glass produced by TAMGLASS Company was processed to be tempered glass by the double chamber hori-zontal tempering furnace production line. The conditions of different preheating ( such as preheat temperature, the up/down convec-tion) on the properties of tempered glass were studied. By adjusting the different parameters of preheating and measurement of tem-pered glass bending, tempered parameters, the paper analyzes the effects of preheating parameters on the performance of the tem-pered glass, and the results are discussed. Results show that the parameters such as preheat temperature, preheat convection en-hance the substrate temperature of glass in the heating period of heat to be faster, better heat evenly;it enhances the smoothness of tempered glass and the apparent quality of the final product has obviously improved. Through the optimal parameter combination, glass products with a group of excellent properties are toughened.%利用TAMGLASS公司生产的双室强对流水平钢化炉生产线对南玻公司生产的6 mm白玻璃进行了钢化处理,研究了不同预热条件(预热温度、上下对流设置等)对钢化玻璃性能的影响。通过调整不同的预热参数以及测量钢化后的玻璃弯曲度、钢化应力、表观质量等参数,分析了预热参数对钢化玻璃性能的影响,并对实验结果进行了讨论。结果表明:设置合适的预热温度、预热对流等参数可提高玻璃的基体温度,使得玻璃在加热段的加热更快、受热更加均匀,提高了钢化玻璃的平整度,对最终产品的表观质量有明显改善。

  15. Cast iron air preheater and commercial application%铸铁式空气预热器及工业应用

    Institute of Scientific and Technical Information of China (English)

    王德瑞

    2012-01-01

    As cast iron has a high corrosion resistance performance, the air preheater fabricated from cast iron material is resistant to corrosion and extended in service life. It is especially applicable for the low-temperature section of waste heat recovery system for industry furnace flue gas. The past and present applications of cast iron air preheaters in boiler, iron & steel production and petrochemical industries are described in detail , and the new development of large cast iron plate air preheater developed by SINOPEC in recent years is presented. Up to now, the large cast iron plate air preheaters have been selected in the design of a large number of fired heaters and its design, fabrication and installation technologies are becoming commercially proven. In April, 2010, China' s first new type cast iron plate air preheater came on stream in No. 2 atmospheric-vacuum distillation unit in No. 2 atmospheric-vacuum distillation unit in SINOPEC Wuhan Petrochemical Company. In 19 months' operation, the heat efficiency of the furnace has been maintained at over 92% and the temperature of flue gas emission was lower than 130 t. The preheater has been operating smoothly ever since.%铸铁具有很强的耐硫酸腐蚀能力,因此,采用铸铁材料制作的空气预热器具有耐腐蚀、长寿命的特点,特别适合在工业炉烟气余热回收系统中的低温段采用.介绍了铸铁式空气预热器在国内锅炉、钢铁和石化行业过去和现在的工业应用情况,以及中国石化近年开发的大型铸铁板式空气预热器的最新进展.目前,国产大型铸铁板式空气预热器已在多台火焰加热炉的设计中采用,设计、制造、安装技术日臻成熟.2010年4月,武汉石化2号常减压蒸馏装置投用了国产第一台新型铸铁板式空气预热器,运行19个月,加热炉热效率一直稳定在92%以上,排烟温度一直稳定在130℃以下,运行良好.

  16. Why $\\Xi(1690)$ and $\\Xi(2120)$ are so narrow?

    CERN Document Server

    Khemchandani, K P; Hosaka, A; Nagahiro, H; Navarra, F S; Nielsen, M

    2016-01-01

    The $\\Xi$ baryons are expected to be naturally narrower as compared to their non-strange and strange counterparts since they have only one light quark and, thus, their decay involves producing either a light meson and doubly strange baryon or both meson and baryon with strangeness which involves, relatively, more energy. In fact, some $\\Xi$'s have full widths of the order of even 10-20 MeV when, in principle, they have a large phase space to decay to some open channels. Such is the case of $\\Xi (1690)$, for which the width has been found to be of the order of 10 MeV in the latest BABAR and BELLE data. In this manuscript we study why some $\\Xi$'s are so narrow. Based on a coupled channel calculation of the pseudoscalar meson-baryon and vector meson-baryon systems with chiral and hidden local symmetry Lagrangians, we find that the answer lies in the intricate hadron dynamics. We find that the known mass, width, spin-parity and branching ratios of $\\Xi (1690)$ can be naturally explained in terms of coupled chann...

  17. Cervical spinal canal narrowing in idiopathic syringomyelia

    Energy Technology Data Exchange (ETDEWEB)

    Struck, Aaron F. [Massachusetts General Hospital, Department of Neurology, Boston, MA (United States); Carr, Carrie M. [Mayo Clinic, Department of Radiology, Rochester, MN (United States); Shah, Vinil [University of California San Francisco, Department of Radiology, San Francisco, CA (United States); Hesselink, John R. [University of California San Diego, Department of Radiology, San Diego, CA (United States); Haughton, Victor M. [University of Wisconsin, Department of Radiology, Madison, WI (United States)

    2016-08-15

    The cervical spine in Chiari I patient with syringomyelia has significantly different anteroposterior diameters than it does in Chiari I patients without syringomyelia. We tested the hypothesis that patients with idiopathic syringomyelia (IS) also have abnormal cervical spinal canal diameters. The finding in both groups may relate to the pathogenesis of syringomyelia. Local institutional review boards approved this retrospective study. Patients with IS were compared to age-matched controls with normal sagittal spine MR. All subjects had T1-weighted spin-echo (500/20) and T2-weighted fast spin-echo (2000/90) sagittal cervical spine images at 1.5 T. Readers blinded to demographic data and study hypothesis measured anteroposterior diameters at each cervical level. The spinal canal diameters were compared with a Mann-Whitney U test. The overall difference was assessed with a Friedman test. Seventeen subjects were read by two reviewers to assess inter-rater reliability. Fifty IS patients with 50 age-matched controls were studied. IS subjects had one or more syrinxes varying from 1 to 19 spinal segments. Spinal canal diameters narrowed from C1 to C3 and then enlarged from C5 to C7 in both groups. Diameters from C2 to C4 were narrower in the IS group (p < 0.005) than in controls. The ratio of the C3 to the C7 diameters was also smaller (p = 0.004) in IS than controls. Collectively, the spinal canal diameters in the IS were significantly different from controls (Friedman test p < 0.0001). Patients with IS have abnormally narrow upper and mid cervical spinal canal diameters and greater positive tapering between C3 and C7. (orig.)

  18. Global viscous overstabilities in narrow rings

    Science.gov (United States)

    Longaretti, Pierre-Yves; French, Richard G.; Nicholson, Philip D.

    2016-10-01

    Local viscous overstabilities have been the focus of a number of theoretical analyses in the last decades due to the rôle they are believed to play in the creation of the small scale structure of broad ring systems (Saturn, Uranus). Global viscous overstabilities have also been investigated in the 1980s and 1990s as a potential source of narrow ring eccentricities (Longaretti and Rappaport, 1995, Icarus, 116, 376).An important feature of global viscous overstabilities is that they produce slow relative librating or circulating motions of narrow ring edges; they may also produce slowly librating or circulating components of edge modes. This process is potentially relevant to explain the occurrence of unusually large apsidal shifts observed in some saturnian ringlets and may also explain the existence of the free m=2 B ring edge mode that is slowly circulating with respect to the component forced by Mimas.The time-scale of such motions is primarily controlled by the ring self-gravity and can be analytically quantified in a two-streamline analysis which yields a characteristic libration/circulation frequency Ωl = (n/π)(Mr/Mp)(a/δa)2H(q2) where n is the mean motion, Mr the ringlet or pertubed region mass, Mp the planet mass, a the semi-major axis, δa the narrow ringlet or pertubed region width and H(q2) a dimensionless factor of order unity that depends on the streamline compression parameter q. The related time-scale is of the order of a few years to a few tens of years depending on the surface density and ringlet/perturbed region geometry. Preliminary data analyzes indicate that the Maxwell and Huyghens ringlets are probably librating with periods consistent with this two-streamline estimate.The talk will briefly present the physics of global viscous overstabilities as well as more detailed applications to narrow rings, and if time permits, to edge modes.

  19. Implications of Halo Inside-out Growth on the X-Ray Properties of Nearby Galaxy Systems within the Preheating Scenario

    CERN Document Server

    Solanes, J M; Gonzalez-Casado, G; Salvador-Solé, E; Solanes, Jose M.; Manrique, Alberto; Gonzalez-Casado, Guillermo; Salvador-Sole, Eduard

    2005-01-01

    We present an entirely analytic model for a preheated, polytropic intergalactic medium in hydrostatic equilibrium within a NFW dark halo potential in which the evolution of the halo structure between major merger events proceeds inside-out by accretion. This model is used to explain, within a standard $\\Lambda$CDM cosmogony, the observed X-ray properties of nearby relaxed, non-cooling flow groups and clusters of galaxies. We find that our preferred solution to the equilibrium equations produces scaling relations in excellent agreement with observations, while simultaneously accounting for the typical structural characteristics of the distribution of the diffuse baryons. In the class of preheating models, ours stands out because it offers a unified description of the intrahalo medium for galaxy systems with total masses above $\\sm 2\\times 10^{13}$\\msun, does not produce baryonic configurations with large isentropic cores, and reproduces faithfully the observed behavior of the gas entropy at large radii. All th...

  20. Exploiting the use of compact heat exchangers on preheating trains; Avaliacao de desempenho de trocadores compactos em bateria de pre-aquecimento - REDUC

    Energy Technology Data Exchange (ETDEWEB)

    Villas Boas, Alan Trugilho; Bolsoni, Adair [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Refinaria de Duque de Caxias (REDUC); Kuboski, Claudio; Cesario, Diomedes [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2008-07-01

    The U-1210 distillation unit of Holding has being expected to suffer a metallurgical adaptation in order to process petroleum with higher naphthenic acids concentration. A heat integration study (pinch analysis) was realized, with the restriction of limited plot area and shut-down time. A full compabloc preheat train was preliminary concept. During conceptual design, REDUC found it to be a good idea to have a performance test. A compabloc CP30 unit has been installed, in order to evaluate the performance of this equipment under unit conditions. The operation service chosen was vacuum residue preheating crude before the dessalter, low crude temperature (100 deg C to 115 deg C). The objective was operational and maintenance experience. (author)

  1. Long-pulse-width narrow-bandwidth solid state laser

    Science.gov (United States)

    Dane, C.B.; Hackel, L.A.

    1997-11-18

    A long pulse laser system emits 500-1000 ns quasi-rectangular pulses at 527 nm with near diffraction-limited divergence and near transform-limited bandwidth. The system consists of one or more flashlamp-pumped Nd:glass zig-zag amplifiers, a very low threshold stimulated-Brillouin-scattering (SBS) phase conjugator system, and a free-running single frequency Nd:YLF master oscillator. Completely passive polarization switching provides eight amplifier gain passes. Multiple frequency output can be generated by using SBS cells having different pressures of a gaseous SBS medium or different SBS materials. This long pulse, low divergence, narrow-bandwidth, multi-frequency output laser system is ideally suited for use as an illuminator for long range speckle imaging applications. Because of its high average power and high beam quality, this system has application in any process which would benefit from a long pulse format, including material processing and medical applications. 5 figs.

  2. Evolution of the plasma bubble in a narrow gap.

    Science.gov (United States)

    Chu, Hong-Yu; Lee, Hung-Ken

    2011-11-25

    We investigate the evolution of the plasma bubble in a narrow gap. According to the morphological changes, we further show that there are three phases during the evolution for spherical fluctuating, radial fingering, and dense branching plasma bubbles, which are similar to the radial fingering pattern in a Hele-Shaw cell. The dependences of the wavelength of the fingering boundary are experimentally discussed. The dense branching plasma bubble is found with a fractal dimension of D(f)=1.74. The reduced surface tension pressure from the local heatings due to the filamentary discharges is suspected of being responsible for the growth of the radial fingering and the dense branching plasma bubbles.

  3. The effect of pre-heating silorane and methacrylate-based composites on microleakage of Class V restorations

    Directory of Open Access Journals (Sweden)

    Soley Arslan

    2012-01-01

    Full Text Available Objective: This study compared the effects of 4 different temperatures (4°C, 25°C, 37°C, 60°C on the microleakage of silorane and methacrylate-based composites in Class V cavities. Materials and Methods: Standard Class V cavities were prepared at the buccal and lingual surfaces of human molars. The specimens were randomly divided into 2 groups according to the composite resin used (Group I: Filtek Silorane Adhesive System and Filtek Silorane composite; Group II: Clearfil SE Bond and Aelite LS Posterior composite and into 4 subgroups according to temperature treatment (Group A: Refrigeration at 4°C; Group B (control: Storage at room temperature (25°C; Group C: Heated to 37°C and Group D: Heated to 60°C using Calset. Specimens were dyed with 0.5% basic fuchsin, sectioned, and evaluated at 25x magnification. Statistical analysis was performed using Mann-Whitney U and Kruskal-Wallis tests at P0.05. Differences in temperature did not significantly affect microleakage values for Filtek Silorane (P>0.05; however, microleakage values of Aelite LS Posterior composite varied according to temperature treatment, with heating resulted in significantly less microleakage than cooling (between Groups IID and IIA and Groups IIC and IIA (P<0.05. Conclusion: Pre-heating was shown to reduce microleakage values of Aelite LS Posterior composite, but did not significantly alter the microleakage values of Filtek Silorane composite.

  4. 提高蒸馏醪液预热温度的研究%Improvement of Distilled Mash Preheat Temperature

    Institute of Scientific and Technical Information of China (English)

    郭传广; 何松贵; 卫云路

    2016-01-01

    In order to improve the distillation efficiency, reduce energy consumption through the transformation of existing retort, increasing the heat transfer area of the heat exchanger, so be distilled mash temperature than the original improved 45.3%, 7.5 single retort distillation save time min, to achieve annual savings of 7.26%of steam. Further, the test vegetarian tasting that wine quality, to improve the preheating temperature of the mash vegetarian wine quality has little effect on stability vegetarian wine quality.%为了提高蒸馏效率,降低能耗,通过对现有蒸馏甑进行改造,增大了换热器的换热面积,使得待蒸馏的醪液温度较原来的提升了45.3%,单甑蒸馏节约时间7.5min,全年可实现节约蒸汽7.26%。另外,通过对试验斋酒质量的品评得知,提高醪液预热温度对斋酒质量影响不大,斋酒质量稳定。

  5. Assessing the 2{omega}{sub pe} instability and other preheat considerations in ignition-scale hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Kruer, W L [University of California, Davis, Davis, CA 95616 (United States); Meezan, Nathan; Town, Richard; Strozzi, David; Wilks, Scott; Williams, Edward; Meeker, Donald; Suter, L S [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Regan, S P, E-mail: wlkruer@ucdavis.ed [Laboratory for Laser Energetics, Rochester, NY 14623 (United States)

    2010-08-01

    In recent experiments[1] Sean Regan, et. al. for the first time observed the 2{omega}{sub pe} instability from window plasma in hohlraum targets. This instability can also operate[2] at peak power near the edge of the inner beams in the ablator plasma and near the edge of the outer beams in the liner plasma. Fortunately only a small fraction of the laser energy was estimated to be at risk. A more quantitative assessment of the energy at risk at peak power will here be given. We show that the instability threshold can be significantly reduced for laser beams with an angle of incidence of about 60 degrees due to the swelling of the laser field near its turning point. A simple model is given. It is also shown that for frequently cited plasma conditions, the Raman-scattered light wave can itself drive the 2{omega}{sub pe}instability. This effect is relevant for the nonlinear saturation of stimulated Raman scattering (SRS) and the resulting heated electron generation. Some estimates are given. Finally we conclude with a few remarks about hot electron preheat.

  6. A methodology to enlarge narrow stability windows

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Ewerton M.P.; Pastor, Jorge A.S.C.; Fontoura, Sergio A.B. [Pontificia Univ. Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil). Dept. de Engenharia Civil. Grupo de Tecnologia e Engenharia de Petroleo

    2004-07-01

    The stability window in a wellbore design is defined by the difference between fracture pressure and collapse pressure. Deep water environments typically present narrow stability windows, because rocks have low strength due to under-compaction process. Often also, horizontal wells are drilled to obtain a better development of reservoirs placed in thin layers of sandstone. In this scenario, several challenges are faced when drilling in deep water. The traditional approach for predicting instabilities is to determine collapses and fractures at borehole wall. However, the initiation of rupture does not indicate that the borehole fails to perform its function as a wellbore. Thus, a methodology in which the stability window may be enlarged is desirable. This paper presents one practical analytical methodology that consists in allowing wellbore pressures smaller than the conventional collapse pressure, i.e., based upon failure on the borehole wall. This means that a collapse region (shear failure) will be developed around the borehole wall. This collapse region is pre-defined and to estimate its size is used a failure criterion. The aforementioned methodology is implemented in a user-friendly software, which can perform analyses of stress, pore pressure, formation failure, mud weight and mud salinity design for drilling in shale formations. Simulations of a wellbore drilling in a narrow stability window environment are performed to demonstrate the improvements of using the methodology. (author)

  7. Cluster headache or narrow angle glaucoma?

    Directory of Open Access Journals (Sweden)

    Prasad Palimar

    1991-01-01

    Full Text Available A 47 year old man with episodes of attacks of pain, redness and mild blurring of vision was investigated for narrow angle glaucoma in view of shallow anterior chambers and a cupped optic disc. The history was reviewed following a spontaneous attack in hospital, which had features other than acute glaucoma. A diagnosis of cluster headache was made on the basis of tests. Cluster headache has been defined as unilateral intense pain, involving the eye and head on one side, usually associated with flushing, nasal congestion and lacrimation; the attacks recurring one or more times daily and lasting 20 - 120 minutes. Such attacks commonly continue for weeks or months and are separated by an asymptomatic period of months to years. This episodic nature, together with unilaterality and tendency to occur at night, closely mimics narrow angle glaucoma. Further, if patients have shallow anterior chambers and disc cupping, the differentiation becomes more difficult yet critical. Resource to provocative tests is often the only answer as the following case report demonstrates.

  8. The Narrow Line Region of Ark 564

    CERN Document Server

    Contini, M; Viegas, S M M; Contini, Marcella; Rodriguez-Ardila, Alberto; Viegas, Sueli

    2003-01-01

    The continuum and emission-line spectrum of the narrow-line Seyfert 1 galaxy Ark 564 is used to investigate, for the first time, the physical conditions and structure of its narrow line region (NLR). For this purpose, composite models, accounting for the coupled effect of photoionization and shocks, are employed. The emission-line spectrum of Ark 564, which ranges from the ultraviolet to the near-infrared, shows a rich forbidden line spectrum. Strong emphasis is given to the study of the coronal line region. The diversity of physical conditions deduced from the observations requires multi-cloud models to reproduce the observed lines and continuum. We find that a combination of high velocity (Vs = 1500 km/s) shock-dominated clouds as well as low velocity (Vs = 150 km/s) radiation-dominated clouds explains the coronal lines, while the optical low-ionization lines are mainly explained by shock-dominated clouds. The results for Ark 564 are compared with those obtained for other Seyfert galaxies previously analyze...

  9. Analysis of sodium experimental circuits pre-heating for the development of nuclear reactors; Analise do pre-aquecimento de circuitos experimentais a sodio para desenvolvimento de reatores nuclares

    Energy Technology Data Exchange (ETDEWEB)

    Bellini, Ione Walmir

    1995-09-01

    To satisfy the experimental requirements of sodium loops for nuclear reactors development, a preheating system, consisting of tubular haters, is analyzed. The tubular heaters are usually comprised of a nickel-chromium wire centered in a metal sheath and insulated by magnesium oxide. Practical and simplified methods for the preheating parameters calculations and for the heaters elements determination and section are presented. A thermal method to evaluate the sodium mass in a tank is presented, using the preheating system, when the tank geometry or the sodium level are unknown. The materials employed and the installation procedures of the preheating system are indicated. It is described a procedure, step, to make the connection between the electrical resistance and the conductor wire, to assure the heat dissipation and the air-tight of the heater element. Several suggestions are presented to clarify some doubts, to define correction factors, to develop technology, and to give continuity to the present work. (author). 37 refs., 22 figs.

  10. PSpectRe: A Pseudo-Spectral Code for (P)reheating

    CERN Document Server

    Easther, Richard; Roth, Nathaniel

    2010-01-01

    PSpectRe is a C++ program that uses Fourier-space pseudo-spectral methods to evolve interacting scalar fields in an expanding universe. PSpectRe is optimized for the analysis of parametric resonance in the post-inflationary universe, and provides an alternative to finite differencing codes, such as Defrost and LatticeEasy. PSpectRe has both second- (Velocity-Verlet) and fourth-order (Runge-Kutta) time integrators. Given the same number of spatial points and/or momentum modes, PSpectRe is not significantly slower than finite differencing codes, despite the need for multiple Fourier transforms at each timestep, and exhibits excellent energy conservation. Further, by computing the post-resonance equation of state, we show that in some circumstances PSpectRe obtains reliable results while using substantially fewer points than a finite differencing code. PSpectRe is designed to be easily extended to other problems in early-universe cosmology, including the generation of gravitational waves during phase transitions...

  11. Development of narrow gap welding technology for extremely thick steel

    Science.gov (United States)

    Imai, K.; Saito, T.; Okumura, M.

    In the field of extremely thick steel, various narrow gap welding methods were developed on the basis of former welding methods and are used in practice. It is important to develop and improve automatic narrow gap welding, J edge preparation by gas cutting, the prevention of welding defects, wires for narrow gap welding and so on in order to expand the scope of application of the method. Narrow gap welding technologies are described, based on new concepts developed by Nippon Steel Corporation.

  12. Promoting L2 Vocabulary Learning through Narrow Reading

    Science.gov (United States)

    Kang, Eun Young

    2015-01-01

    Krashen (2004) has advocated that narrow reading, i.e., reading a series of texts addressing one specific topic, is an effective method to grow vocabulary. While narrow reading has been championed to have many advantages for L2 vocabulary learning, there remains a relative dearth of empirical studies that test the impact of narrow reading on L2…

  13. The Narrow Line Region of Narrow-Line Seyfert 1 Galaxies

    CERN Document Server

    Rodríguez-Ardila, A; Pastoriza, M G; Donzelli, C J

    2000-01-01

    This work studies the optical emission line properties and physical conditions of the narrow line region (NLR) of seven narrow-line Seyfert 1 galaxies (NLS1). Our results show that the flux carried out by the narrow component of H-beta is, on average, 50% of the total line flux. As a result, the [OIII] 5007/H-beta ratio emitted in the NLR varies from 1 to 5, instead of the universally adopted value of 10. This has strong implications for the required spectral energy distribution that ionizes the NLR gas. Photoionization models that consider a NLR composed of a combination of matter-bounded and ionization-bounded clouds are successful at explaining the low [OIII] 5007/H-beta ratio and the weakness of low-ionization lines of NLS1s. Variation of the relative proportion of these two type of clouds nicely reproduce the dispersion of narrow line ratios found among the NLS1 sample. Assuming similar physical model parameters of both NLS1s and the normal Seyfert 1 galaxy NGC 5548, we show that the observed differences...

  14. Narrow-Bicliques: Cryptanalysis of Full IDEA

    DEFF Research Database (Denmark)

    Khovratovich, D.; Leurent, G.; Rechberger, C.

    2012-01-01

    We apply and extend the recently introduced biclique framework to IDEA and for the first time describe an approach to noticeably speed-up key-recovery for the full 8.5 round IDEA.We also show that the biclique approach to block cipher cryptanalysis not only obtains results on more rounds, but also...... improves time and data complexities over existing attacks. We consider the first 7.5 rounds of IDEA and demonstrate a variant of the approach that works with practical data complexity. The conceptual contribution is the narrow-bicliques technique: the recently introduced independent-biclique approach...... the practical use of IDEA in any way, yet the techniques are practically verified to a large extent....

  15. Robotic chair at steep and narrow stairways

    Science.gov (United States)

    Imazato, Masahiro; Yamaguchi, Masahiro; Moromugi, Shunji; Ishimatsu, Takakazu

    2007-12-01

    A robotic chair is developed to support mobility of elderly and disabled people living in the house where steep and narrow stairways are installed. In order to deal with such mobility problem the developed robotic chair has a compact original configuration. The robotic chair vertically moves by actuation of electric cylinders and horizontally moves by push-pull operation given by a care-giver. In order to navigate safely every action of the chair is checked by the operator. Up-and-down motions of the robotic chair on the stairway are executed through combinations of motor and cylinder actuations. Performance of the robotic chair was evaluated through two kinds of experiments. The excellent ability of the robotic chair could be confirmed through these experiments.

  16. Diluted magnetic semiconductors with narrow band gaps

    Science.gov (United States)

    Gu, Bo; Maekawa, Sadamichi

    2016-10-01

    We propose a method to realize diluted magnetic semiconductors (DMSs) with p - and n -type carriers by choosing host semiconductors with a narrow band gap. By employing a combination of the density function theory and quantum Monte Carlo simulation, we demonstrate such semiconductors using Mn-doped BaZn2As2 , which has a band gap of 0.2 eV. In addition, we found a nontoxic DMS Mn-doped BaZn2Sb2 , of which the Curie temperature Tc is predicted to be higher than that of Mn-doped BaZn2As2 , the Tc of which was up to 230 K in a recent experiment.

  17. Tissue characterization by using narrow band imaging

    Science.gov (United States)

    Gono, Kazuhiro

    2010-02-01

    NBI (Narrow Band Imaging) was first introduced in the market in 2005 as a technique enabling to enhance image contrast of capillaries on a mucosal surface(1). It is classified as an Optical-Digital Method for Image-Enhanced Endoscopy(2). To date, the application has widely spread not only to gastrointestinal fields such as esophagus, stomach and colon but also the organs such as bronchus and bladder. The main target tissue of NBI enhancement is capillaries. However, findings of many clinical studies conducted by endoscopy physicians have revealed that NBI observation enables to enhance more other structures in addition to capillaries. There is a close relationship between those enhanced structures and histological microstructure of a tissue. This report introduces the tissue microstructures enhanced by NBI and discusses the possibility of optimized illumination wavelength in observing living tissues.

  18. Effect of pre-heated dual-cured resin cements on the bond strength of indirect restorations to dentin

    Directory of Open Access Journals (Sweden)

    Alexandre Morais

    2012-04-01

    Full Text Available This study evaluated the effects of resin luting agents (LA polymerized using increased temperature on the in vitro microtensile bond strength (mTBS of indirect restorations to dentin. The occlusal dentin surfaces of 40 human third molars were exposed and flattened. The teeth were assigned to 8 groups (n = 5 according to the LA temperature (25°C o r 50°C, curing mode (dual- or self-curing mode, and product (Excite DSC/Variolink II [VII] and XP Bond/Calibra [Cal]. The bonding agents were applied to the dentin surfaces according to manufacturers' instructions. For preheated groups, the LAs were heated to 50°C, subsequently mixed on a heated stirrer surface, and applied to the previously heated pre-polymerized resin discs (2 mm thickness, TPH-Spectrum. The discs were bonded to the dentin surfaces, and the LAs were either exposed to a curing light according to manufacturers' instructions or allowed to self-cure. Specimens were stored in relative humidity at 37°C for 7 days. Specimens were mesio-distally and bucco-lingually sectioned to obtain multiple bonded beams with a 1-mm² cross-sectional area for mTBS testing. Data (MPa were analyzed by 2-way ANOVA and Tukey's post hoc test (a = 5% for each product. Specimen failure patterns were analyzed using a scanning electron microscope. VII groups showed higher mTBS at 50°C than at 25°C regardless of curing mode (p = 0.05. Cal groups showed similar mTBS at 25°C and 50°C in all activation modes. The use of some dual-polymerizing LAs at 50°C may improve the mTBS of indirect restorations to dentin.

  19. On the narrow emission line components of the LMC novae 2004 (YY Dor) and 2009a

    CERN Document Server

    Mason, Elena

    2014-01-01

    We present early decline spectra of the two Large Magellanic Cloud novae: LMC 2004 (YY Dor) and LMC 2009a and discuss their spectral an line profile evolution with special emphasis on the existence and appearance of a sharp component. We show that the narrow component that characterizes the emission lines in the maximum spectra of nova LMC 2004 originates in the ejecta. The HeII 4686 A, narrow emission which appears at the onset of the nebular phase in both novae is somewhat controversial. Our observations suggest that the corresponding line forming region is physically separated from the rest of the ejecta (the broad line region) and environmentally different. However, the lack of late time observations covering the super-soft source (SSS) phase, the post-SSS phase and the quiescence state does not allow to securely establish any non-ejecta origin/contribution as, instead, in the case of U Sco and KT Eri.

  20. Enhancement for Φ-OTDR performance by using narrow linewidth light source and signal processing

    Science.gov (United States)

    Zhang, Meng; Wang, Song; Zheng, Yuanwei; Yang, Yao; Sa, Xingjie; Zhang, Li

    2016-03-01

    In order to enhance the signal-to-noise-ratio of a distributed acoustic sensing system based on phase-sensitive optical time-domain reflectometry (Φ-OTDR), we have proposed a combination of segmented unwrapping algorithm, averaging estimation of phase difference, and infinite impulse response (IIR) filtering method. The enhancement of signal quality is numerically demonstrated. Moreover, we have studied the influence resulted from the light source noise on the Φ-OTDR performance. The result has shown that when the linewidth of light source used in the Φ-OTDR system is narrower, the performance of the system is better. In a word, such a Φ-OTDR system could obtain higher quality demodulated signals when the narrower linewidth light source is chosen and the method of averaging estimation phase difference is used.

  1. Automatic Narrow-Deep Feature Recognition for Mould Manufacturing

    Institute of Scientific and Technical Information of China (English)

    Zheng-Ming Chen; Kun-Jin He; Jing Liu

    2011-01-01

    There usually exist narrow-long-deep areas in mould needed to be machined in special machining. To identify the narrow-deep areas automatically, an automatic narrow-deep feature (NF) recognition method is put forward accordingly. First, the narrow-deep feature is defined innovatively in this field and then feature hint is extracted from the mould by the characteristics of narrow-deep feature. Second, the elementary constituent faces (ECF) of a feature are found on the basis of the feature hint. By means of extending and clipping the ECF, the feature faces are obtained incrementally by geometric reasoning. As a result, basic narrow-deep features (BNF) related are combined heuristically. The proposed NF recognition method provides an intelligent connection between CAD and CAPP for machining narrow-deep areas in mould.

  2. ANALYSIS AND MEASUREMENT OF STOKES LAYER FLOWS IN AN OSCILLATING NARROW CHANNEL

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The velocities of boundary layer flows between two parallel oscillating plates separated by small distance, i.e., in so called narrow channel, were theoretically and experimentally studied. The focus was on the laminar case where the Reynolds number is much smaller than the transition value. The theoretical analysis of the Stokes layer in oscillating flow over a narrow channel was made first. Then Laser Doppler Velocimeter (LDV) was employed to measure the Stokes boundary layer above an oscillating flat plate and inside the oscillating narrow channel at various numbers. At the same time, the phase angle difference along the vertical direction in both analysis and experiment were provided. The good agreements are shown between the measured results and the theoretical solution.

  3. Experimental study on convective boiling heat transfer in narrow-gap annulus tubes

    Institute of Scientific and Technical Information of China (English)

    LI Bin; ZHAO Jian-Fu; ZHOU Fang-De; TANG Ze-Mei; HU Wen-Rui

    2004-01-01

    Since convective boiling or highly subcooled single-phase forced convection in micro-channels is an effective cooling mechanism with a wide range of applications, more experimental and theoretical studies are required to explain and verify the forced convection heat transfer phenomenon in narrow channels. In this experimental study, we model the convective boiling behavior of water with low latent heat substance Freon 113 (R-113), with the purpose of saving power consumption and visualizing experiments. Both heat transfer and pressure drop characteristics were measured in subcooled and saturated concentric narrow gap forced convection boiling. Data were obtained to qualitatively identify the effects of gap size, pressure, flow rate and wall superheat on boiling regimes and the transition between various regimes. Some significant differences from unconfined forced convection boiling were found,and also, the flow patterns in narrow vertical annulus tubes have been studied quantitatively.

  4. TESTS AND METHODOLOGIES FOR THE SURVEY OF NARROW SPACES

    Directory of Open Access Journals (Sweden)

    L. Perfetti

    2017-02-01

    Full Text Available The research illustrated in this article aimed at identifying a good standard methodology to survey very narrow spaces during 3D investigation of Cultural Heritage. It is an important topic in today’s era of BIM modelling applied to Cultural Heritage. Spaces like staircases, corridors and passages are very common in the architectural or archaeological fields, and obtaining a 3D-oriented survey of those areas can be a very complex task when completeness of the model and high precision are requested. Photogrammetry appears to be the most promising solution in terms of versatility and manoeuvrability also considering the quality of the required data. Fisheye lenses were studied and tested in depth because of their significant advantage in the field of view if compared with rectilinear lenses. This advantage alone can be crucial to reduce the total amount of photos and, as a consequence, to obtain manageable data, to simplify the survey phase and to significantly reduce the elaboration time. In order to overcome the main issue that arise when using fisheye lenses, which is the lack of rules that can be employed to design the survey, a general mathematical formulation to precisely estimate the GSD (Ground Sampling Distance for every optical projection is presented here. A complete survey of a real complex case study was performed in order to test and stress the proposed methodology, and to handle a fisheye-based survey from beginning to end: the photogrammetric survey of the Minguzzi Staircase. It is a complex service spiral-staircase located in the Duomo di Milano with a total height of 25 meters and characterized by a narrow walkable space about 70 centimetres wide.

  5. Experimental Study on Convective Boiling Heat Transfer in Vertical Narrow Gap Annular Tube

    Institute of Scientific and Technical Information of China (English)

    Li Bin; He Anding; Wang Yueshe; Zhou Fangde

    2001-01-01

    Experiments are conducted to investigate the characteristics of single-phase forced-flow convection and boiling heat transfer of R113 flowing through annular tube with gap of 1, 1.5 and 2.5 mm, and also the visualization test are carried out to get two-phase flow regime. The data show that the Nusselt numbers for the narrow-gap are higher than those predicted by traditional large channel correlation and boiling heat transfer is enhanced. Based on the data obtained in this investigation, correlations for single-phase, forced convection and flow boiling in annular tube of different gap size has been developed.

  6. Diging simulation of a narrow trench

    Science.gov (United States)

    Anghelache, D. G.; Goanta, A. M.

    2016-08-01

    In this paper, we realized digging process simulation for a narrow trench using special equipment located at a mini excavator. These types of machines digging perform the longitudinal direction to the direction of travel, making trenches with widths of 0.4 m and depths of 3.5 -7.0 m. These are necessary for the location of underground cables or draining water in agriculture. For Parametric modelling of parts included in ensemble has used software from Siemens NX 7.5, we produce sketches of each piece, using following commands: Sketch, Profile (Line), Arc, Circle, Quick Trim Quick Extend, Constraints. Depending on the layout of each piece can also use other commands such as: Chamfer, Rotate, Mirror Curve, Offset Curve, etc. After completion of sketch and dimensioning commands was: Extrude, Revolve, and at this stage the play may various modifications such as drilling, removal of certain volumes of piece showing various forms or change the appearance of surfaces (thread cutting, bevelling). This paper was realized with this parametric modelling software because presents major advantages including: control over the design, making design speed and increasing productivity; increasing product quality, reducing design risk recovery and time work, less human effort and reduced financial resources throughout the process.

  7. Narrow and broad senses on salinity scale

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The narrow sense and applicable limit of Practical Salinity Scale 1978 (PSS78) and volumetric titration using silver nitrate to measure the salinity of non-conservative oceanwater are discussed.The salinity obtained by electrical conductivity method and chlorinity salinity method obviously deviates from the absolute salinity (SA). The Density Salinity Scale (DSS98) proposed by the writers can be extensively used in conservative and non-conservative water samples.The merits of the density salinity scale are as follows,(1) The Density Salinity Scale is only related to seawater mass and its buoyant effect, and is not influenced by the variation in seawater composition, and therefore, has high reliability, and repeatability for salinity determination.(2) The salinity values measured by the DSS98 have a conservative property. For oceanwater samples the salinity values are the same as those determined by the PSS78; for non-conservative water samples (e.g. samples from industrial sources), the salinity values are close to the absolute salinity values in comparison with those measured by the PSS78 and the Knudsen method.(3)For a solution with given solute mass, the solution concentration can be converted into the corresponding salinity by the Density Salinity Scale using the expansion coefficient of the solution and the calibration coefficient of the partial molar volume of the solute.

  8. Narrowing of the ITCZ in a warming climate: Physical mechanisms

    Science.gov (United States)

    Byrne, Michael P.; Schneider, Tapio

    2016-11-01

    The Intertropical Convergence Zone (ITCZ) narrows in response to global warming in both observations and climate models. However, a physical understanding of this narrowing is lacking. Here we show that the narrowing of the ITCZ in simulations of future climate is related to changes in the moist static energy (MSE) budget. MSE advection by the mean circulation and MSE divergence by transient eddies tend to narrow the ITCZ, while changes in net energy input to the atmosphere and the gross moist stability tend to widen the ITCZ. The narrowing tendency arises because the meridional MSE gradient strengthens with warming, whereas the largest widening tendency is due to increasing shortwave heating of the atmosphere. The magnitude of the ITCZ narrowing depends strongly on the gross moist stability and clouds, emphasizing the need to better understand these fundamental processes in the tropical atmosphere.

  9. Effect of Preheating and Precooling on the Flexural Strength and Modulus of Elasticity of Nanohybrid and Silorane-based Composite

    Directory of Open Access Journals (Sweden)

    Farahnaz Sharafeddin

    2015-09-01

    Full Text Available Statement of the Problem: Composite resin may be used in different temperatures; it is crucial to determine the effect of temperature on mechanical properties of nanohybrid and silorane-based composite. Purpose: This in vitro study compared the flexural strength and modulus of elasticity of nanohybrid and silorane-based resin composite, at 4˚C, room temperature (25˚C, and 45˚C. Materials and Method: In this experimental study, 60 specimens were prepared in a metal split mold (2×2×25mm. Two different resin composites, Filtek Z250 XT (3M/ ESPE and Filtek P90 (3M/ESPE, were evaluated. The material were inserted into split molds at room temperature, 4˚C or 45˚C and cured with LED (1200 mW/cm2 for 20 seconds in four points (n=10. Then, a three-point bending test was performed using a universal testing machine at a crosshead speed of 0.5 mm/min for measuring the flexural strength and flexural modulus of samples. The data were analyzed by the two-way ANOVA and Tukey test (p< 0.05. Results: The mean highest flexural strength was observed at 45˚C, showing statistically significant difference with flexural strength at 4˚C (p= 0.0001 and 25˚C (p= 0.003 regardless of the type of resin composite. The flexural modulus at 45˚C was highest, showing the statistically significant difference with flexural modulus at 4˚C (p= 0.0001 and 25˚C (p= 0.002. The flexural modulus was statistically different between nanohybrid and silorane-based resin composite (p= 0.01 in 25˚C and 45˚C, but there were no statistically significant differences between flexural strength of Filtek Z250 XT and Filtek P90 regardless of the temperatures (p= 0.062. Conclusion: Preheating the resin composite at 45˚C improves flexural strength and modulus of nanohybrid and silorane-based resin composite. However, flexural strength and modulus of the tested materials were not affected by precooling. The flexural modulus of nanohybrid resin composite was significantly higher than

  10. Laser frequency bandwidth narrowing by photorefractive two-beam coupling.

    Science.gov (United States)

    Chomsky, D; Sternklar, S; Zigler, A; Jackel, S

    1992-04-01

    We present a theoretical analysis and experimental demonstration of a new method for spectral narrowing of laser radiation. The bandwidth narrowing is experienced by a laser beam subjected to a photorefractive two-beam coupling process. Contrary to the conventional method of frequency filtering by a Fabry-Perot étalon, this technique has no intrinsic finesse limitation on its resolution. A factor of 2 in frequency bandwidth narrowing is achieved with an argon-ion laser.

  11. The effects of late homogenization conditions on the Mg2Si particle size in a slow pre-heated 6063 aluminum extrusion billet

    Science.gov (United States)

    Kayıkcı, R.; Kocaman, E.; Şirin, S.; ćolak, M.

    2015-03-01

    In order to investigate the effect of late homogenization conditions on the Mg2Si precipitation of 6063 grade extrusion billets are slow pre-heated to intentionally have large Mg2Si particle precipitation. Then the billets are water quenched to preserve this microstructure for late homogenizations. Finally billets are re-heated using two different furnace temperature as 450°C and 500°C at which temperatures the billet are held for 0.5 h, 1 h, 1.5 h, 2 h and 2.5 h periods and water quenched before being taken to metallographic examinations.

  12. An Analysis of the Microstructure, Macrostructure and Microhardness of Nicr-Ir Joints Produced by Laser Welding with and without Preheat

    Directory of Open Access Journals (Sweden)

    Różowicz S.

    2016-06-01

    Full Text Available This paper discusses some of the basic problems involved in laser welding of dissimilar materials with significant differences in melting points. It focuses on the micro and macrostructure of laser welded NiCr-Ir microjoints used in central spark plug electrodes. The joints were produced by welding with and without preheat using an Nd,YAG laser. The structure and composition of the welded joints were analyzed by means of a light microscope (LM and a scanning electron microscope (SEM equipped with an energy dispersive X-ray (EDX spectrometer. The microhardness of the weld area was also studied.

  13. Enhancement of gas phase heat transfer by acoustic field application.

    Science.gov (United States)

    Komarov, Sergey; Hirasawa, Masahiro

    2003-06-01

    This study discusses a possibility for enhancement of heat transfer between solids and ambient gas by application of powerful acoustic fields. Experiments are carried out by using preheated Pt wires (length 0.1-0.15 m, diameter 50 and 100 micro m) positioned at the velocity antinode of a standing wave (frequency range 216-1031 Hz) or in the path of a travelling wave (frequency range 6.9-17.2 kHz). A number of experiments were conducted under conditions of gas flowing across the wire surface. Effects of sound frequency, sound strength, gas flow velocity and wire preheating temperature on the Nusselt number are examined with and without sound application. The gas phase heat transfer rate is enhanced with acoustic field strength. Higher temperatures result in a vigorous radiation from the wire surface and attenuate the effect of sound. The larger the gas flow velocity, the smaller is the effect of sound wave on heat transfer enhancement.

  14. Vortex formation in magnetic narrow rings

    Science.gov (United States)

    Bland, J. A. C.

    2002-03-01

    Underlying the current interest in magnetic elements is the possibility such systems provide both for the study of fundamental phenomena in magnetism (such as domain wall trapping and spin switching) and for technological applications, such as high density magnetic storage or magnetic random access memories (MRAM). One key issue is to control the magnetic switching precisely. To achieve this one needs first to have a well defined and reproducible remanent state, and second the switching process itself must be simple and reproducible. Among the many studied geometries, rings are shown to exhibit several advantages over other geometries, in that they show relatively simple stable magnetic states at remanence, with fast and simple magnetisation switching mechanisms. This is borne out of our systematic investigation of the magnetic properties of epitaxial and polycrystalline Co rings, where both the static, dynamic and transport properties have been studied. Magnetic measurements and micromagnetic simulations show that for appropriate ring structures a two step switching process occurs at high fields, indicating the existence of two different stable states. In addition to the vortex state, which occurs at intermediate fields, we have identified a new bi-domain state, which we term the `onion state', corresponding to opposite circulation of the magnetisation in each half of the ring. The magnetic elements were fabricated using a new technique based on the pre-patterning of Si ring structures and subsequent epitaxial growth of Cu/Co/Cu sandwich films on top of the Si elements. This technique has allowed the growth of epitaxial fcc Co(001) structures and in contrast to conventional lithographic methods, no damage to the magnetic layer structure is introduced by the patterning process [1,2]. We have studied the magnetic switching properties of arrays of narrow Co(100) epitaxial ring magnets, with outer diameters between 1 μm and 2 μm, varying inner diameters and varying

  15. TESTING DIFFERENT SURVEY TECHNIQUES TO MODEL ARCHITECTONIC NARROW SPACES

    Directory of Open Access Journals (Sweden)

    A. Mandelli

    2017-08-01

    Full Text Available In the architectural survey field, there has been the spread of a vast number of automated techniques. However, it is important to underline the gap that exists between the technical specification sheet of a particular instrument and its usability, accuracy and level of automation reachable in real cases scenario, especially speaking about Cultural Heritage (CH field. In fact, even if the technical specifications (range, accuracy and field of view are known for each instrument, their functioning and features are influenced by the environment, shape and materials of the object. The results depend more on how techniques are employed than the nominal specifications of the instruments. The aim of this article is to evaluate the real usability, for the 1:50 architectonic restitution scale, of common and not so common survey techniques applied to the complex scenario of dark, intricate and narrow spaces such as service areas, corridors and stairs of Milan’s cathedral indoors. Tests have shown that the quality of the results is strongly affected by side-issues like the impossibility of following the theoretical ideal methodology when survey such spaces. The tested instruments are: the laser scanner Leica C10, the GeoSLAM ZEB1, the DOT DPI 8 and two photogrammetric setups, a full frame camera with a fisheye lens and the NCTech iSTAR, a panoramic camera. Each instrument presents advantages and limits concerning both the sensors themselves and the acquisition phase.

  16. Mechanical filtering for narrow-band hearing in the weta.

    Science.gov (United States)

    Lomas, Kathryn; Montealegre-Z, Fernando; Parsons, Stuart; Field, Larry H; Robert, Daniel

    2011-03-01

    This paper constitutes a major attempt to associate tympanic deflections with the mechanoreceptor organ location in an acoustic insect. The New Zealand tree weta (Hemideina thoracica) has tympanal ears located on each of the prothoracic tibiae. The tympana exhibit a sclerotized oval plate, membranous processes bulging out from the tibial cuticle and many loosely suspended ripples. We used microscanning laser Doppler vibrometry to determine how such a tympanal membrane vibrates in response to sound and whether the sclerotized region plays a role in hearing. The tympanum displays a single resonance at the calling frequency of the male, an unusual example of an insect tympana acting as a narrow bandpass filter. Both tympana resonate in phase with the stimulus and with each other. Histological sections show that the tympanal area is divided into two distinct regions, as in other ensiferans. An oval plate lies in the middle of a thickened region and is surrounded by a transparent and uniformly thin region. It is hinged dorsally to the tympanal rim and thus resembles the model of a 'hinged flap'. The thickened region appears to act as a damping mass on the oscillation of the thin region, and vibration displacement is reduced in this area. The thinner area vibrates with higher amplitude, inducing mechanical pressure on the dorsal area adjacent to the crista acustica. We present a new model showing how the thickened region might confer a mechanical gain onto the activation of the crista acustica sensory neurons during the sound-induced oscillations.

  17. Testing Different Survey Techniques to Model Architectonic Narrow Spaces

    Science.gov (United States)

    Mandelli, A.; Fassi, F.; Perfetti, L.; Polari, C.

    2017-08-01

    In the architectural survey field, there has been the spread of a vast number of automated techniques. However, it is important to underline the gap that exists between the technical specification sheet of a particular instrument and its usability, accuracy and level of automation reachable in real cases scenario, especially speaking about Cultural Heritage (CH) field. In fact, even if the technical specifications (range, accuracy and field of view) are known for each instrument, their functioning and features are influenced by the environment, shape and materials of the object. The results depend more on how techniques are employed than the nominal specifications of the instruments. The aim of this article is to evaluate the real usability, for the 1:50 architectonic restitution scale, of common and not so common survey techniques applied to the complex scenario of dark, intricate and narrow spaces such as service areas, corridors and stairs of Milan's cathedral indoors. Tests have shown that the quality of the results is strongly affected by side-issues like the impossibility of following the theoretical ideal methodology when survey such spaces. The tested instruments are: the laser scanner Leica C10, the GeoSLAM ZEB1, the DOT DPI 8 and two photogrammetric setups, a full frame camera with a fisheye lens and the NCTech iSTAR, a panoramic camera. Each instrument presents advantages and limits concerning both the sensors themselves and the acquisition phase.

  18. Narrow band noise response of a Belleville spring resonator.

    Science.gov (United States)

    Lyon, Richard H

    2013-09-01

    This study of nonlinear dynamics includes (i) an identification of quasi-steady states of response using equivalent linearization, (ii) the temporal simulation of the system using Heun's time step procedure on time domain analytic signals, and (iii) a laboratory experiment. An attempt has been made to select material and measurement parameters so that nearly the same systems are used and analyzed for all three parts of the study. This study illustrates important features of nonlinear response to narrow band excitation: (a) states of response that the system can acquire with transitions of the system between those states, (b) the interaction between the noise source and the vibrating load in which the source transmits energy to or draws energy from the load as transitions occur; (c) the lag or lead of the system response relative to the source as transitions occur that causes the average frequencies of source and response to differ; and (d) the determination of the state of response (mass or stiffness controlled) by observation of the instantaneous phase of the influence function. These analyses take advantage of the use of time domain analytic signals that have a complementary role to functions that are analytic in the frequency domain.

  19. Quantum transport in narrow-gap semiconductor nanocolumns

    Energy Technology Data Exchange (ETDEWEB)

    Lueth, H.; Bloemers, C.; Richter, T.; Wensorra, J.; Estevez Hernandez, S.; Petersen, G.; Lepsa, M.; Schaepers, T.; Marso, M.; Indlekofer, M.; Calarco, R.; Demarina, N.; Gruetzmacher, D. [Institute of Bio- and Nanosystems (IBN-1) and Juelich Aachen Research Alliance (JARA), Research Center Juelich (Germany)

    2010-02-15

    InN nanowires were grown by plasma-assisted MBE in a bottom-up approach, while InAs nanocolumns were prepared top-down by electron beam lithography. Both types of narrow-gap semiconductor nanocolumns exhibit a surface accumulation with a cylinder-like 2 DEG as conduction channel. In magnetoconductance measurements at low temperatures with the magnetic field parallel to the column axis the InN wires exhibit magnetoconductance oscillations with a repetition period of a magnetic flux quantum {phi}{sub 0}. For the InAs columns the observed magnetoconductance oscillations have a period of half the flux quantum {phi}{sub 0}/2. The interpretation is based on the different surface perfectness of both types of columns. The InN wires with an almost perfect crystallinity allow transport through coherent angular momentum states within the surface 2 DEG which yields a {phi}{sub 0} periodicity. The InAs column surfaces exhibit a high amount of surface defects arising from the preparation and only diffusive, phase conserving transport through the 2 DEG is possible, which allows Al'tshuler-Aronov-Spivak interferences with a period {phi}{sub 0}/2. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Observation of Motion Dependent Nonlinear Dispersion with Narrow Linewidth Atoms in an Optical Cavity

    CERN Document Server

    Westergaard, Philip G; Tieri, David; Matin, Rastin; Cooper, John; Holland, Murray; Ye, Jun; Thomsen, Jan W

    2014-01-01

    As an alternative to state-of-the-art laser frequency stabilisation using ultra-stable cavities, it has been proposed to exploit the non-linear effects from coupling of atoms with a narrow atomic transition to an optical cavity. Here we have constructed such a system and observed non-linear phase shifts of a narrow optical line by strong coupling of a sample of strontium-88 atoms to an optical cavity. The sample temperature of a few mK provides a domain where the Doppler energy scale is several orders of magnitude larger than the narrow linewidth of the optical transition. This makes the system sensitive to velocity dependent multi-photon scattering events (Dopplerons) that affect the cavity transmission significantly while leaving the phase signature relatively unaffected. By varying the number of atoms and the intra-cavity power we systematically study this non-linear phase signature which displays roughly the same features as for much lower temperature samples. This demonstration in a relatively simple sys...

  1. The Case for the Narrow View of Reading

    Science.gov (United States)

    Kamhi, Alan G.

    2009-01-01

    Purpose: This prologue reiterates the case for the narrow view of reading as a solution to the persistently high levels of reading failure that occurs in our schools and provides a brief summary of the 5 response articles. Method: The arguments that support the narrow view of reading are presented and the respondents are introduced. Conclusion:…

  2. Narrow band tuning with small long pulse excimer lasers

    Energy Technology Data Exchange (ETDEWEB)

    Sze, R.C.; Kurnit, N.; Watkins, D.; Bigio, I.

    1985-12-01

    We discuss frequency narrowing and tuning with simple dispersion elements with small long-pulse excimer lasers. The improved performance over short-pulse lasers is discussed and attributed to the increased number of round trips. A physical model of the dynamics of line narrowing is presented.

  3. Bayesian Face Recognition and Perceptual Narrowing in Face-Space

    Science.gov (United States)

    Balas, Benjamin

    2012-01-01

    During the first year of life, infants' face recognition abilities are subject to "perceptual narrowing", the end result of which is that observers lose the ability to distinguish previously discriminable faces (e.g. other-race faces) from one another. Perceptual narrowing has been reported for faces of different species and different races, in…

  4. Channel Narrowing and Channel Reset: Effects of a Large Flood on the Vegetated, Narrowing Rio Grande

    Science.gov (United States)

    Dean, D. J.; Schmidt, J. C.

    2009-12-01

    In September 2008, heavy precipitation from a tropical storm in the Sierra Madre Occidental, MX, produced large amounts of stream flow to the Rio Conchos and lower Rio Grande. This flood was well publicized in the media due to the widespread flooding in Ojinaga, Chih., and Presidio, TX. Gage records indicate that this flood had an approximate recurrence of 15 years as measured on the Rio Grande near Presidio. Nevertheless, flood stages were the highest ever recorded and resulted from a significant loss of channel capacity due to channel narrowing that had occurred during the previous 18 years. Measurements from aerial photographs indicate that channel width had decreased between 35 and 50% between 1990 and 2008 during regional drought. During this period of low stream flow, invasion by non-native riparian vegetation (Tamarix spp., Arundo donax) helped trap sediment and promote floodplain accretion. Our resurveys of the channel indicate that the 2008 flood was a reset event and that the channel was re-widened by 32 to 48%. Repeated, oblique photographs showed significant channel migration and large scale floodplain stripping during this flood. These results show that although riparian vegetation may actively promote channel narrowing and floodplain accretion, moderately large floods may cause large scale bank erosion, floodplain stripping, and vegetation removal in alluvial valleys subject to large-scale invasion by nonnative plants.

  5. Band Gap Narrowing and Widening of ZnO Nanostructures and Doped Materials

    OpenAIRE

    2015-01-01

    Band gap change in doped ZnO is an observed phenomenon that is very interesting from the fundamental point of view. This work is focused on the preparation of pure and single phase nanostructured ZnO and Cu as well as Mn-doped ZnO for the purpose of understanding the mechanisms of band gap narrowing in the materials. ZnO, Zn0.99Cu0.01O and Zn0.99Mn0.01O materials were prepared using a wet chemistry method, and X-ray diffraction (XRD) results showed that all samples were pure and single phase....

  6. Note: Efficient diode laser line narrowing using dual, feed-forward + feed-back laser frequency control

    Science.gov (United States)

    Lintz, M.; Phung, D. H.; Coulon, J.-P.; Faure, B.; Lévèque, T.

    2017-02-01

    We have achieved distributed feedback laser diode line narrowing by simultaneously acting on the diode current via a feed-back loop and on an external electrooptic phase modulator in feed-forward actuator. This configuration turns out to be very efficient in reaching large bandwidth in the phase correction: up to 15 MHz with commercial laser control units. About 98% of the laser power undergoes narrowing. The full width at half maximum of the narrowed optical spectrum is of less than 4 kHz. This configuration appears to be very convenient as the delay in the feed-forward control electronics is easily compensated for by a 20 m optical fiber roll.

  7. Are narrow mesons, baryons and dibaryons evidence for multiquark states?

    Energy Technology Data Exchange (ETDEWEB)

    Tatischeff, B.; Yonnet, J. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire

    2000-07-01

    Several narrow structures have been progressively observed since the last fifteen years, in di-baryonic invariant mass spectra or in missing mass spectra. More recently, narrow structures were observed in baryonic and now in mesonic mass spectra. Since these small peaks appear at fixed masses, independently of the experiment, they are associated with real states. There is no room to explain these states within classical nuclear physics taking into account baryonic and mesonic degrees of freedom. An interpretation is proposed, which associate these narrow structures with two coloured quark clusters. (authors)

  8. Narrowing of Terrace-width Distributions During Growth on Vicinals

    Science.gov (United States)

    Hamouda, Ajmi Bh.; Pimpinelli, A.; Einstein, T. L.

    2009-03-01

    Using kinetic Monte Carlo simulations for a generic minimal SOS model of vicinal surfaces, we compute the terrace-width distributions (TWDs) as a function of incident flux during homoepitaxial growth. We show that the distribution narrows markedly, U.B.P.-Clermont 2 as though there were a flux-dependent repulsion between steps, until the step picture fails at high flux. Using a Fokker-Planck approach, we analyze the evolution and saturation of this narrowing. We compare with a 1D model and with our simulations for narrowing due to an Ehrlich-Schwoebel barrier.

  9. Band Gap Narrowing and Widening of ZnO Nanostructures and Doped Materials.

    Science.gov (United States)

    Kamarulzaman, Norlida; Kasim, Muhd Firdaus; Rusdi, Roshidah

    2015-12-01

    Band gap change in doped ZnO is an observed phenomenon that is very interesting from the fundamental point of view. This work is focused on the preparation of pure and single phase nanostructured ZnO and Cu as well as Mn-doped ZnO for the purpose of understanding the mechanisms of band gap narrowing in the materials. ZnO, Zn0.99Cu0.01O and Zn0.99Mn0.01O materials were prepared using a wet chemistry method, and X-ray diffraction (XRD) results showed that all samples were pure and single phase. UV-visible spectroscopy showed that materials in the nanostructured state exhibit band gap widening with respect to their micron state while for the doped compounds exhibited band gap narrowing both in the nano and micron states with respect to the pure ZnO materials. The degree of band gap change was dependent on the doped elements and crystallite size. X-ray photoelectron spectroscopy (XPS) revealed that there were shifts in the valence bands. From both UV-visible and XPS spectroscopy, it was found that the mechanism for band gap narrowing was due to the shifting of the valance band maximum and conduction band minimum of the materials. The mechanisms were different for different samples depending on the type of dopant and dimensional length scales of the crystallites.

  10. Thermal calculation method for quad-sectional regenerative air preheater%四分仓回转式空气预热器热力计算方法

    Institute of Scientific and Technical Information of China (English)

    陈昌贤; 孙奉仲; 李飞; 吴艳艳

    2014-01-01

    A new thermal calculation model for quad-sectional regenerative air preheater was investigated based on the analysis of operating mode and heat transfer characteristics of quad-sectional air preheaters.The model included two cal-culating steps:the average outlet flue gas temperature and the weighted average outlet air temperature were obtained through the first step calculation;and based on the first step calculation results, the average outlet air temperatures were obtained in right-secondary airside, primary air side and left-secondary airside respectively by the second step calcula-tion.The results showed that the maximum and minimum relative deviations between calculated values and design val-ues were 2.27% and 0.21% respectively.For a 300 MW circulating fluidized bed boiler unit with quad-sectional air preheater, the maximum and average relative deviations between calculated values and actual operation data were 4%and 1.8%respectively, the accuracy and reliability of this thermal calculation model were verified.%基于四分仓空气预热器的运行方式和传热特点的分析,建立了先合仓再分仓的热力计算模型。模型包含合仓和分仓两步计算,通过合仓计算获得平均出口烟温和有加权的平均出口风温;利用合仓计算结果进行分仓计算,获得右二次风仓、一次风仓和左二次风仓的平均出口风温。结果表明,计算值与设计值的最大相对偏差为2.27%,最小相对偏差为0.21%。以某300 MW循环流化床锅炉机组的四分仓空气预热器为实例,在4个常用工况下,计算值与实际运行数据的最大相对偏差为4%,平均相对偏差为1.8%,验证了此计算方法的准确性和可靠性。

  11. Stopping Narrow-Band X-Ray Pulses in Nuclear Media

    Science.gov (United States)

    Kong, Xiangjin; Pálffy, Adriana

    2016-05-01

    A control mechanism for stopping x-ray pulses in resonant nuclear media is investigated theoretically. We show that narrow-band x-ray pulses can be mapped and stored as nuclear coherence in a thin-film planar x-ray cavity with an embedded 57Fe nuclear layer. The pulse is nearly resonant to the 14.4 keV Mössbauer transition in the 57Fe nuclei. The role of the control field is played here by a hyperfine magnetic field which induces interference effects reminiscent of electromagnetically induced transparency. We show that, by switching off the control magnetic field, a narrow-band x-ray pulse can be completely stored in the cavity for approximately 100 ns. Additional manipulation of the external magnetic field can lead to both group velocity and phase control of the pulse in the x-ray cavity sample.

  12. Integrating narrow therapeutic index drug formulations in transplantation

    NARCIS (Netherlands)

    A. Johnston (Andrew); L. Schick (Liz); T. van Gelder (Teun)

    2012-01-01

    textabstractThere is considerable debate regarding generic drug substitution in solid organ transplant recipients, and various European transplant associations and societies have expressed caution about the potential adverse consequences from uncontrolled switching between the different narrow

  13. Single Frequency Narrow Linewidth 2 Micron Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA needs narrow linewidth lasers in the 1.5 or 2 micron wavelength regime for coherent Lidar applications. The laser should be tunable by several nm and frequency...

  14. Comment on the narrow structure reported by Amaryan et al

    CERN Document Server

    Anghinolfi, M; Baltzell, N A; Battaglieri, M; Bedlinskiy, I; Bellis, M; Biselli, A S; Bookwalter, C; Boiarinov, S; Bosted, P; Burkert, V D; Carman, D S; Celentano, A; Chandavar, S; Cole, P L; Crede, V; De Vita, R; De Sanctis, E; Dey, B; Dickson, R; Doughty, D; Dugger, M; Dupre, R; Egiyan, H; Alaoui, A El; Fassi, L El; Elouadrhiri, L; Eugenio, P; Fedotov, G; Gabrielyan, M Y; Garcon, M; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Golovatch, E; Guidal, M; Guo, L; Hafidi, K; Hakobyan, H; Heddle, D; Hicks, K; Holtrop, M; Ireland, D G; Ishkhanov, B S; Isupov, E L; Jo, H S; Joo, K; Khetarpal, P; Kim, A; Kim, W; Kubarovsky, V; Kuleshov, S V; Lu, H Y; MacGregor, L J D; Markov, N; McCracken, M E; McKinnon, B; Mestayer, M D; Meyer, C A; Mirazita, M; Mokeev, V; Moriya, K; Morrison, B; Ni, A; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Ostrovidov, A I; Park, K; Park, S; Pereira, S Anefalos; Pisano, S; Pogorelko, O; Pozdniakov, S; Price, J W; Ricco, G; Ripani, M; Ritchie, B G; Rossi, P; Schott, D; Schumacher, R A; Seder, E; Sharabian, Y G; Smith, E S; Sober, D I; Stepanyan, S S; Stoler, P; Tang, W; Ungaro, M; Vernarsky, B; Vineyard, M F; Weygand, D P; Wood, M H; Zachariou, N; Zhao, B

    2012-01-01

    The CLAS Collaboration provides a comment on the physics interpretation of the results presented in a paper published by M. Amaryan et al. regarding the possible observation of a narrow structure in the mass spectrum of a photoproduction experiment.

  15. Novel bioequivalence approach for narrow therapeutic index drugs.

    Science.gov (United States)

    Yu, L X; Jiang, W; Zhang, X; Lionberger, R; Makhlouf, F; Schuirmann, D J; Muldowney, L; Chen, M-L; Davit, B; Conner, D; Woodcock, J

    2015-03-01

    Narrow therapeutic index drugs are defined as those drugs where small differences in dose or blood concentration may lead to serious therapeutic failures and/or adverse drug reactions that are life-threatening or result in persistent or significant disability or incapacity. The US Food and Drug Administration proposes that the bioequivalence of narrow therapeutic index drugs be determined using a scaling approach with a four-way, fully replicated, crossover design study in healthy subjects that permits the simultaneous equivalence comparison of the mean and within-subject variability of the test and reference products. The proposed bioequivalence limits for narrow therapeutic index drugs of 90.00%-111.11% would be scaled based on the within-subject variability of the reference product. The proposed study design and data analysis should provide greater assurance of therapeutic equivalence of narrow therapeutic index drug products.

  16. STUDY OF HYDRODYNAMIC FORCES OF SHIPS IN NARROW WATERWAY

    Institute of Scientific and Technical Information of China (English)

    Zhang Xie-dong; Wu Xiu-heng

    2003-01-01

    The collision of ships in narrow waterway may occur for a variety of reasons. The hydrodynamic forces between two ships change the maneuvering characteristics of ships greatly. So based on the boundary element method, this paper proposes a calculation method for hydrodynamic interaction forces between ships under meeting and passing conditions in narrow waterway. The results from this method are compared with the existing results obtained from other theoretical approaches, and they are in good agreement.

  17. Combination Effect of Dry-Ice Blasting and Substrate Preheating on Plasma-Sprayed CoNiCrAlY Splats

    Science.gov (United States)

    Dong, Shujuan; Song, Bo; Hansz, Bernard; Liao, Hanlin; Coddet, Christian

    2013-02-01

    CoNiCrAlY splats were plasma-sprayed on the stainless steel substrate which was pretreated by dry-ice blasting. Only impact marks were distinguished on the glycerol-polluted substrate, while halo donut splats formed on the pretreated substrate because of the cleaning effect of dry-ice blasting on this organic substance. The proportions of different splat types vary as a function of the treatment time of dry-ice blasting. The condensation phenomenon was also detected on the substrate surface accompanying the cleaning effect after the pretreatment of dry-ice blasting. In this study, dry-ice blasting was investigated to be coupled with substrate preheating to control the substrate temperature. It was found that a regular disk-like CoNiCrAlY splat can be obtained as the substrate temperature is higher than dew point temperature.

  18. Development of an expert system for preheating temperatures determination. Desarrollo dse uns sistema experto para la determinacion de temperatura de precalentamiento

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, E.; Silva, M.; Gonalvez, P.; Fernandez, A.A. (Oporto Univ. (Portugal) Facultad de Ingenieria)

    1989-01-01

    This work describes the development of an expert system designed to control the cold fissuration phenomenon caused by H{sup 2} on welded joints of carbonated, C-Mn and light alloy steels, obtained through fusion welding (manual electric arc, MIG/MAG, TIG and submerged arc). This system, implemented in PROLOG language, allows a quick and simple calculation of preheating temperatures. The aim of this system, which does not require programming knowledge to be updated, is to help welding engineers to design welding procedures which are safe as regards to the joint resistance to cold fissuration. Being an expert system, the user has the opportunity to obtain interactive explanations about the way any conclusions are obtained, as well as information about the concepts and parameters on which the reasoning is based.(Author)

  19. Narrow linewidth Yb-doped double-cladding fiber laser utilizing fiber Bragg gratings inscribed by femtosecond pulses

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zhinan; Shi Jiawei; Zhang Jihuang; Wang Haiyan; Li Yuhua; Lu Peixiang, E-mail: oeyhli@gmail.com, E-mail: lupeixiang@mail.hust.edu.cn [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2011-02-01

    A narrow-linewidth high power laser in all fiber format at 1064 nm is demonstrated. The resonant cavity is composed of two distributed Bragg reflector (DBR) fiber gratings, which were inscribed into the core of the double-cladding fiber by use of 800 nm femtosecond laser pulses and a phase mask. The spectrum of the laser exhibited a narrow linewidth of 21 pm at the output power of 0.8 W. The wavelength and power of the laser featured long term stability.

  20. 组合式空气预热器振动原因分析及解决措施%CAUSE ANALYSIS FOR THE VIBRATION OFCOMBINED AIR PREHEATER AND THE SOLUTION

    Institute of Scientific and Technical Information of China (English)

    颜祥富; 侯杰; 龙运国

    2012-01-01

    某组合式空气预热器试运行时产生强烈振动,文章对空气预热器产生震动的原因进行了分析,指出卡门涡流是预热器产生振动的主要原因,因为当气流横向绕流管束时,卡门涡流的交替脱落会引起空气预热器中气柱的振动.当漩涡的脱落频率(fK)与管箱的声学驻波振动频率接近或一致时,会诱发强烈的管箱声学驻波振动,造成空气预热器管箱的共振.为了消除振动,对预热器进行了改造:沿换热管方向安装消振隔板,将预热器从上至下贯通均等分成3个气室(相当于减小气室宽度),以提高气室固有频率及振风量.改造后预热器的卡门涡流频率和气室固有频率不会重合,也就不会产生声学共振.通过改造,该预热器消除了振动,恢复了正常的运行,确保炼化加热炉高效、长周期安全稳定运转.%Certain combined air preheater produced strong vibration during test run. This paper analyzes the causes for the vibration of the air preheater and points out that Karman vortex is the main reason for the vibration of the preheater because the alternating shedding of Karman vortex may cause the column vibration of the air preheater when the air flows through the tube bundle transversely. When the vortex shedding frequency ( /k ) and the frequency of the acoustic standing wave vibration of the tube box is close to each other or consistent, strong acoustic standing wave vibration of the tube box will be induced. And this may cause the resonance of the tube box of the air preheater. In order to eliminate the vibration, the preheater has been transformed. Vibration elimination separators are installed along the heat transfer tube direction and the preheater is divided into three equal chambers from the top to the bottom, which equals to reducing the width of the chamber. This may increase the natural frequency of the chamber and the vibration air volume. After the transformation, the Karman vortex

  1. Brilliant GeV electron beam with narrow energy spread generated by a laser plasma accelerator

    Science.gov (United States)

    Hu, Ronghao; Lu, Haiyang; Shou, Yinren; Lin, Chen; Zhuo, Hongbin; Chen, Chia-erh; Yan, Xueqing

    2016-09-01

    The production of GeV electron beam with narrow energy spread and high brightness is investigated using particle-in-cell simulations. A controlled electron injection scheme and a method for phase-space manipulation in a laser plasma accelerator are found to be essential. The injection is triggered by the evolution of two copropagating laser pulses near a sharp vacuum-plasma transition. The collection volume is well confined and the injected bunch is isolated in phase space. By tuning the parameters of the laser pulses, the parameters of the injected electron bunch, such as the bunch length, energy spread, emittance and charge, can be adjusted. Manipulating the phase-space rotation with the rephasing technique, the injected electron bunch can be accelerated to GeV level while keeping relative energy spread below 0.5% and transverse emittance below 1.0 μ m . The results present a very promising way to drive coherent x-ray sources.

  2. Nasal base narrowing: the alar flap advancement technique.

    Science.gov (United States)

    Ismail, Ahmed Soliman

    2011-01-01

    To evaluate the role of creating an alar-based advancement flap in narrowing the nasal base and correcting excessive alar flare. Case series with chart review. This is a retrospective record review study. The study included 35 cases presenting with a wide nasal base and excessive alar flaring. The surgical procedure combined the alar base reduction with alar flare excision by creating a single laterally based alar flap. Any caudal septal deformities and any nasal tip modification procedures were corrected before the nasal base narrowing. The mean follow-up period was 23 months. The mean alar flap narrowing was 6.3 mm, whereas the mean width of sill narrowing was 2.9 mm. This single laterally based advancement alar flap resulted in a more conservative external resection, thus avoiding alar wedge overresection or blunting of the alar-facial crease. No cases of postoperative bleeding, infection, or keloid were encountered, and the external alar wedge excision healed with no apparent scar that was hidden in the depth of the alar-facial crease. The risk of notching of the alar rim at the sill incision is reduced by adopting a 2-layer closure of the vestibular floor. The alar base advancement flap is an effective technique in narrowing both the nasal base and excessive alar flare. It adopts a single skin excision to correct the 2 deformities while commonly feared complications were avoided.

  3. Multi-wavelength narrow linewidth fiber laser based on distributed feedback fiber lasers

    Science.gov (United States)

    Lv, Jingsheng; Qi, Haifeng; Song, Zhiqiang; Guo, Jian; Ni, Jiasheng; Wang, Chang; Peng, Gangding

    2016-09-01

    A narrow linewidth laser configuration based on distributed feedback fiber lasers (DFB-FL) with eight wavelengths in the international telecommunication union (ITU) grid is presented and realized. In this laser configuration, eight phase-shifted gratings in series are bidirectionally pumped by two 980-nm laser diodes (LDs). The final laser output with over 10-mW power for each wavelength can be obtained, and the maximum power difference within eight wavelengths is 1.2 dB. The laser configuration with multiple wavelengths and uniform power outputs can be very useful in large scaled optical fiber hydrophone fields.

  4. Prospects for a Narrow Line MOT in YO

    CERN Document Server

    Collopy, Alejandra L; Yeo, Mark; Yan, Bo; Ye, Jun

    2015-01-01

    In addition to being suitable for laser cooling and trapping in a magneto-optical trap (MOT) using a relatively broad ($\\sim$5 MHz) transition, the molecule YO possesses a narrow-line transition. This forbidden transition between the $X^{2}\\Sigma$ and $A'^{2}\\Delta_{3/2}$ states has linewidth $\\sim$2$\\pi\\times$160 kHz. After cooling in a MOT on the $X^{2}\\Sigma$ to $A^{2}\\Pi_{1/2}$ (orange) transition, the narrow (red) transition can be used to further cool the sample, requiring only minimal additions to the first stage system. The narrow line cooling stage will bring the temperature from $\\sim$1 mK to $\\sim$10 $\\mu$K, significantly advancing the frontier on direct cooling achievable for molecules.

  5. Prospects for a narrow line MOT in YO

    Science.gov (United States)

    Collopy, Alejandra L.; Hummon, Matthew T.; Yeo, Mark; Yan, Bo; Ye, Jun

    2015-05-01

    In addition to being suitable for laser cooling and trapping in a magneto-optical trap (MOT) using a relatively broad (∼ 5 MHz) transition, the molecule YO possesses a narrow-line transition. This forbidden transition between the {{X}2}Σ and A{{\\prime }2}{{Δ }3/2} states has linewidth ∼ 2π × 160 kHz. After cooling in a MOT on the 614 nm {{X}2}Σ to {{A}2}{{\\Pi }1/2} (orange) transition, the narrow 690 nm (red) transition can be used to further cool the sample, requiring only minimal additions to the first stage system. We estimate that the narrow line cooling stage will bring the temperature from ∼1 mK to ∼10 μK, significantly advancing the frontier on direct cooling achievable for molecules.

  6. Temporal intensity interferometry for characterization of very narrow spectral lines

    Science.gov (United States)

    Tan, P. K.; Kurtsiefer, C.

    2017-08-01

    Some stellar objects exhibit very narrow spectral lines in the visible range additional to their blackbody radiation. Natural lasing has been suggested as a mechanism to explain narrow lines in Wolf-Rayet stars. However, the spectral resolution of conventional astronomical spectrographs is still about two orders of magnitude too low to test this hypothesis. We want to resolve the linewidth of narrow spectral emissions in starlight. A combination of spectral filtering with single-photon-level temporal correlation measurements breaks the resolution limit of wavelength-dispersing spectrographs by moving the linewidth measurement into the time domain. We demonstrate in a laboratory experiment that temporal intensity interferometry can determine a 20-MHz-wide linewidth of Doppler-broadened laser light and identify a coherent laser light contribution in a blackbody radiation background.

  7. CT demonstration of pharyngeal narrowing in adult obstructive sleep apnea

    Energy Technology Data Exchange (ETDEWEB)

    Bohlman, M.E. (Johns Hopkins Univ. School of Medicine, Baltimore, MD); Haponik, E.F.; Smith, P.L.; Allen, R.P.; Bleecker, E.R.; Goldman, S.M.

    1983-03-01

    Sleep apnea is a major cause of daytime hypersomnolence. Among the proposed etiologies, focal obstruction of the airways at the level of the pharynx has been suggested but not proven. Using computed tomography, the cross-sectional area of the airway can be readily assessed. Thirty-three adults with clinically proven sleep apnea and 12 normal adults underwent systematic computed tomography of the neck. Significant airway narrowing was demonstrated in all the patients with obstructive sleep apnea, whereas no such narrowing was seen in the controls. In 11, the narrowing was at a single level, whereas in 22 patients two or more levels were affected. This study has shown that a structurally abnormal airway may serve as an anatomic substrate for the development of sleep apnea. On the basis of this evidence, uvulopalatopharyngoplasty has been performed in two patients with relief of symptoms in one.

  8. Multilayer Photonic Crystal for Spectral Narrowing of Emission

    Directory of Open Access Journals (Sweden)

    Zhanfang LIU

    2017-08-01

    Full Text Available Multilayer colloidal crystal has been prepared by the layer-by-layer deposition of silica microspheres on a glass slide. Each layer is a slab consisting of a fcc close-packed colloidal arrays. By properly choosing the sizes of spheres, the whole spectral feature of multilayer colloidal crystal can be tuned. Here, we engineered a multilayer superlattice structure with an effective passband between two stop bands. This gives a strong narrowing effect on emission spectrum. With the stop bands at the shortwave and longwave edges of emission spectrum, the passband in the central wavelength region can be regarded as a strong decrease of suppression effect and enhancement of a narrow wavelength region of emission. The spectral narrowing modification effect of suitably engineered colloidal crystals shows up their importance in potential application as optical filters and lasing devices.DOI: http://dx.doi.org/10.5755/j01.ms.23.3.16320

  9. Thermoviscoelastic dynamic response for a composite material thin narrow strip

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Hong Liang; Qi, Li-Li; Liu, Hai-Bo [Hunan University, Changsha (China)

    2015-02-15

    Based on von Karman nonlinear strain-displacement relationships and classical thin plate theory, a list of nonlinear dynamic equilibrium equations for a viscoelastic composite material thin narrow strip under thermal and mechanic loads are deduced. According to the material constitutive relationship and the relaxation modulus in the form of the Prony series, combing with the Newmark method and the Newton-cotes integration method, a new numerical algorithm for direct solving the whole problem in the time domain is established. By applying this numerical algorithm, the viscoelastic composite material thin narrow strip as the research subject is analyzed systematically, and its rich dynamical behaviors are revealed comprehensively. To verify the accuracy of the present work, a comparison is made with previously published results. Finally, the viscoelastic composite material thin narrow strip under harmonic excitation load and impact load are discussed in detail, and many valuable thermoviscoelastic dynamic characteristics are revealed.

  10. Search for narrow resonances lighter than Upsilon mesons

    Energy Technology Data Exchange (ETDEWEB)

    Aaltonen, T.; /Helsinki Inst. of Phys.; Adelman, Jahred A.; /Chicago U., EFI; Akimoto, T.; /Tsukuba U.; Alvarez Gonzalez, B.; /Cantabria Inst. of Phys.; Amerio, S.; /INFN, Padua; Amidei, Dante E.; /Michigan U.; Anastassov, A.; /Northwestern U.; Annovi, Alberto; /Frascati; Antos, Jaroslav; /Comenius U.; Apollinari, G.; /Fermilab; Apresyan, A.; /Purdue U. /Waseda U.

    2009-03-01

    We report a search for narrow resonances, produced in p{bar p} collisions at {radical}s = 1.96 TeV, that decay into muon pairs with invariant mass between 6.3 and 9.0 GeV/c{sup 2}. The data, collected with the CDF II detector at the Fermilab Tevatron collider, correspond to an integrated luminosity of 630 pb{sup -1}. We use the dimuon invariant mass distribution to set 90% upper credible limits of about 1% to the ratio of the production cross section times muonic branching fraction of possible narrow resonances to that of the {Upsilon}(1S) meson.

  11. Infrared Perfect Ultra-narrow Band Absorber as Plasmonic Sensor

    OpenAIRE

    Wu, Dong; Liu, Yumin; Li, Ruifang; Chen, Lei; Ma, Rui; Liu, Chang; Ye, Han

    2016-01-01

    We propose and numerically investigate a novel perfect ultra-narrow band absorber based on a metal-dielectric-metal-dielectric-metal periodic structure working at near-infrared region, which consists of a dielectric layer sandwiched by a metallic nanobar array and a thin gold film over a dielectric layer supported by a metallic film. The absorption efficiency and ultra-narrow band of the absorber are about 98 % and 0.5 nm, respectively. The high absorption is contributed to localized surface ...

  12. Dilute Oxygen Combustion Phase 3 Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Riley, M.F.; Ryan, H.M.

    2000-05-31

    Dilute Oxygen Combustion (DOC) burners have been successfully installed and operated in the reheat furnace at Auburn Steel Co., Inc., Auburn, NY, under Phase 3 of the Dilute Oxygen Combustion project. Two new preheat zones were created employing a total of eight 6.5 MMBtu/hr capacity burners. The preheat zones provide a 30 percent increase in maximum furnace production rate, from 75 tph to 100 tph. The fuel rate is essentially unchanged, with the fuel savings expected from oxy-fuel combustion being offset by higher flue gas temperatures. When allowance is made for the high nitrogen level and high gas phase temperature in the furnace, measured NOx emissions are in line with laboratory data on DOC burners developed in Phase 1 of the project. Burner performance has been good and there have been no operating or maintenance problems. The DOC system continues to be used as part of Auburn Steel?s standard reheat furnace practice. High gas phase temperature is a result of the high firing density needed to achieve high production rates, and little opportunity exists for improvement in that area. However, fuel and NOx performance can be improved by further conversion of furnace zones to DOC burners, which will lower furnace nitrogen levels. Major obstacles are cost and concern about increased formation of oxide scale on the steel. Oxide scale formation may be enhanced by exposure of the steel to higher concentrations of oxidizing gas components (primarily products of combustion) in the higher temperature zones of the furnace. Phase 4 of the DOC project will examine the rate of oxide scale formation in these higher temperature zones and develop countermeasures that will allow DOC burners to be used successfully in these furnace zones.

  13. Dilute Oxygen Combustion - Phase 3 Report

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Michael F.

    2000-05-31

    Dilute Oxygen Combustion (DOC) burners have been successfully installed and operated in the reheat furnace at Auburn Steel Co., Inc., Auburn, NY, under Phase 3 of the Dilute Oxygen Combustion project. Two new preheat zones were created employing a total of eight 6.5 MMBtu/hr capacity burners. The preheat zones provide a 30 percent increase in maximum furnace production rate, from 75 tph to 100 tph. The fuel rate is essentially unchanged, with the fuel savings expected from oxy-fuel combustion being offset by higher flue gas temperatures. When allowance is made for the high nitrogen level and high gas phase temperature in the furnace, measured NOx emissions are in line with laboratory data on DOC burners developed in Phase 1 of the project. Burner performance has been good, and there have been no operating or maintenance problems. The DOC system continues to be used as part of Auburn Steel's standard reheat furnace practice. High gas phase temperature is a result of the high firing density needed to achieve high production rates, and little opportunity exists for improvement in that area. However, fuel and NOx performance can be improved by further conversion on furnace zones to DOC burners, which will lower furnace nitrogen levels. Major obstacles are cost and concern about increased formation of oxide scale on the steel. Oxide scale formation may be enhanced by exposure of the steel to higher concentrations of oxidizing gas components (primarily products of combustion) in the higher temperature zones of the furnace. Phase 4 of the DOC project will examine the rate of oxide scale formation in these higher temperature zones and develop countermeasures that will allow DOC burners to be used successfully in these furnace zones.

  14. Narrow-Band WGM Optical Filters With Tunable FSRs

    Science.gov (United States)

    Mohageg, Makan; Matsko, Andrey; Savchenkov, Anatoliy; Maleki, Lute; Iltchenko, Vladimir; Strekalov, Dmitry

    2007-01-01

    Optical resonators of the whispering-gallery-mode (WGM) type featuring DC-tunable free spectral ranges (FSRs) have been demonstrated. By making the FSR tunable, one makes it possible to adjust, during operation, the frequency of a microwave signal generated by an optoelectronic oscillator in which an WGM optical resonator is utilized as a narrow-band filter.

  15. Elongational viscosity of narrow molar mass distribution polystyrene

    DEFF Research Database (Denmark)

    Bach, Anders; Almdal, Kristoffer; Rasmussen, Henrik Koblitz

    2003-01-01

    Transient and steady elongational viscosity has been measured for two narrow molar mass distribution polystyrene melts of molar masses 200 000 and 390 000 by means of a filament stretching rheometer. Total Hencky strains of about five have been obtained. The transient elongational viscosity rises...

  16. Nonstationary Narrow-Band Response and First-Passage Probability

    DEFF Research Database (Denmark)

    Krenk, Steen

    1979-01-01

    The notion of a nonstationary narrow-band stochastic process is introduced without reference to a frequency spectrum, and the joint distribution function of two consecutive maxima is approximated by use of an envelope. Based on these definitions the first passage problem is treated as a Markov po...

  17. Molecular targets of Narrow-Band UVB Phototherapy in Psoriasis

    NARCIS (Netherlands)

    E. Rácz (Emőke)

    2009-01-01

    textabstractPsoriasis is a chronic inflammatory skin disease that affects 2-3% of the Western population. The aim of this thesis was to illuminate the molecular effects of narrow-band (NB-) UVB phototherapy, a highly effective systemic treatment modality in psoriasis, in order to clarify the mechani

  18. 33 CFR 162.240 - Tongass Narrows, Alaska; navigation.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Tongass Narrows, Alaska; navigation. 162.240 Section 162.240 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY INLAND WATERWAYS NAVIGATION REGULATIONS § 162.240...

  19. Mechanical properties of Indonesian-made narrow dynamic compression plate.

    Science.gov (United States)

    Dewo, P; van der Houwen, E B; Sharma, P K; Magetsari, R; Bor, T C; Vargas-Llona, L D; van Horn, J R; Busscher, H J; Verkerke, G J

    2012-09-01

    Osteosynthesis plates are clinically used to fixate and position a fractured bone. They should have the ability to withstand cyclic loads produced by muscle contractions and total body weight. The very high demand for osteosynthesis plates in developing countries in general and in Indonesia in particular necessitates the utilisation of local products. In this paper, we investigated the mechanical properties, i.e. proportional limit and fatigue strength of Indonesian-made Narrow Dynamic Compression Plates (Narrow DCP) as one of the most frequently used osteosynthesis plates, in comparison to the European AO standard plate, and its relationship to geometry, micro structural features and surface defects of the plates. All Indonesian-made plates appeared to be weaker than the standard Narrow DCP because they consistently failed at lower stresses. Surface defects did not play a major role in this, although the polishing of the Indonesian Narrow DCP was found to be poor. The standard plate showed indications of cold deformation from the production process in contrast to the Indonesian plates, which might be the first reason for the differences in strength. This is confirmed by hardness measurements. A second reason could be the use of an inferior version of stainless steel. The Indonesian plates showed lower mechanical behaviour compared to the AO-plates. These findings could initiate the development of improved Indonesian manufactured DCP-plates with properties comparable to commonly used plates, such as the standard European AO-plates.

  20. Gain-switched all-fiber laser with narrow bandwidth

    DEFF Research Database (Denmark)

    Larsen, Casper; Giesberts, M.; Nyga, S.;

    2013-01-01

    Gain-switching of a CW fiber laser is a simple and cost-effective approach to generate pulses using an all-fiber system. We report on the construction of a narrow bandwidth (below 0.1 nm) gain-switched fiber laser and optimize the pulse energy and pulse duration under this constraint. The extracted...

  1. Electronic structure of heavy fermions: narrow temperature-independent bands

    Energy Technology Data Exchange (ETDEWEB)

    Arko, A.J.; Joyce, J.J.; Andrews, A.B.; Thompson, J.D.; Smith, J.L. [Los Alamos National Lab., NM (United States); Moshopoulou, E.; Fisk, Z. [NHMFL, Florida State Univ., Tallahassee, FL (United States); Menovsky, A.A. [Amsterdam Univ. (Netherlands). Natuurkundig Lab.; Canfield, P.C.; Olson, C.G. [Iowa State Univ., Ames, IA (United States). Ames Lab.

    1997-02-01

    The electronic structure of both Ce and U heavy fermions appears to consist of extremely narrow temperature independent bands. There is no evidence from ARPES data reported here for a collective phenomenon normally referred to as the Kondo resonance. In uranium compounds a small dispersion of the bands is easily measurable. (orig.).

  2. The electronic structure of heavy fermions: Narrow temperature independent bands

    Energy Technology Data Exchange (ETDEWEB)

    Arko, A.J.; Joyce, J.J.; Smith, J.L.; Andrews, A.B. [and others

    1996-08-01

    The electronic structure of both Ce and U heavy fermions appears to consist of extremely narrow temperature independent bands. There is no evidence from photoemission for a collective phenomenon normally referred to as the Kondo resonance. In uranium compounds a small dispersion of the bands is easily measurable.

  3. A "Narrowing of Inquiry" in American Moral Psychology and Education

    Science.gov (United States)

    Richardson, Michael J.; Slife, Brent D.

    2013-01-01

    We explore the possibility that a priori philosophical commitments continue to result in a narrowing of inquiry in moral psychology and education where theistic worldviews are concerned. Drawing from the theories of Edward L. Thorndike and John Dewey, we examine naturalistic philosophical commitments that influenced the study of moral psychology…

  4. Jakob Müller-Systems and Solutions for Narrow Fabrics

    Institute of Scientific and Technical Information of China (English)

    Wang Ting

    2010-01-01

    @@ Founded in Switzerland in 1887,Jakob Müller AG is one of the world leaders in technology for the manufacture of woven and knitted tapes and webbing,woven labels,technical textiles,woven ropes,printed narrow fabrics,dyeing,make-up and winding machinery.

  5. Reduced dosages of atrazine and narrow rows can provide ...

    African Journals Online (AJOL)

    hope&shola

    2010-11-08

    Nov 8, 2010 ... weeding to keep the crop weed-free and avert yield losses (Mashingaidze and ..... (1998) who reported little benefit in maize to narrow row spacings as a .... analysis of crop rotation effects on weed seed banks. Am. J. Bot. 82:.

  6. The Baldwin effect in the narrow emission lines of AGNs

    CERN Document Server

    Zhang, Kai; Gaskell, C Martin; Dong, Xiao-Bo

    2012-01-01

    The anti-correlations between the equivalent widths of emission lines and the continuum luminosity in AGNs, known as the Baldwin effect are well established for broad lines, but are less well studied for narrow lines. In this paper we explore the Baldwin effect of narrow emission lines over a wide range of ionization levels and critical densities using a large sample of broad-line, radio-quiet AGNs taken from Sloan Digital Sky Survey (SDSS) Data Release 4. These type1 AGNs span three orders of magnitude in continuum luminosity. We show that most narrow lines show a similar Baldwin effect slope of about -0.2 while the significant deviations of the slopes for [NII] 6583, [OII] 3727, [NeV] 3425, and the narrow component of Ha can be explained by the influence of metallicity, star-formation contamination and possibly by difference in the shape of the UV-optical continuum. The slopes do not show any correlation with either the ionization potential or the critical density. We show that a combination of 50% variatio...

  7. QCD Signatures of Narrow Graviton Resonances in Hadron Colliders

    CERN Document Server

    Bijnens, J; Maul, M; Mansson, A; Sjöstrand, Torbjörn

    2001-01-01

    We show that the characteristic p_\\perp spectrum yields valuable information for the test of models for the production of narrow graviton resonances in the TeV range at LHC. Furthermore, it is demonstrated that in those scenarios the parton showering formalism agrees with the prediction of NLO matrix element calculations.

  8. Acute and chronic response to CRT in narrow QRS patients.

    Science.gov (United States)

    Donahue, Tim; Niazi, Imran; Leon, Angel; Stucky, Michael; Herrmann, Keith

    2012-04-01

    Previous studies suggest that CRT may benefit narrow QRS patients with mechanical dyssynchrony (MD). We conducted an acute and chronic study, evaluating the response of heart failure patients with a narrow QRS to cardiac resynchronization therapy (CRT). ESTEEM-CRT was a multi-center, single-arm, feasibility study that evaluated ICD-indicated, medically-optimized patients with EF ≤ 35%, NYHA class III heart failure, QRS duration <120 ms, and MD as defined by the standard deviation of time to peak systolic velocity of 12 segments (Ts-SD). Sixty-eight patients received a CRT defibrillator, exercise testing, and echo exams, and 47 of these patients underwent invasive hemodynamic testing at implant. Follow-up was at 6 and 12 months. The average maximal improvement in LV dP/dt(max) was minor (2 ± 2%). NYHA and quality of life scores were substantially improved at 6 and 12 months (P < 0.001), while exercise capacity and LV volumes were unchanged. The echo indices of MD were difficult to collect, discordant, and failed to predict clinical outcomes. ESTEEM-CRT patients with a narrow QRS and MD as defined in this study did not improve as measured by acute hemodynamics, chronic exercise performance, or reverse remodeling. These multi-center results support the notion that dyssynchrony indices are ineffective or at least require greater refinement for the selection of narrow QRS patients for CRT.

  9. Narrow Near-Threshold Resonance in e+-He+ Scattering

    Institute of Scientific and Technical Information of China (English)

    LIU Min-Min; HAN Hui-Li; GU Si-Hong; SHI Ting-Yun

    2012-01-01

    An independent alternative calculation is performed for narrow near-threshold resonances in the e+-He+ system using the stabilization method in the framework of hyperspherical coordinates (HSSM).A narrow resonance at Er =-0.249995 with width T =1.9 × 10-5,associated with the He2+-Ps(n =1) threshold is confirmed.The resonances around the energies -0.365 and -0.195,predicted by Bhatia and Drachman [Phys.Rev.A 42 (1990)5117] and confirmed by Ho [Phys.Rev.A 53 (1996)3165],do not appear in our calculations.%An independent alternative calculation is performed for narrow near-threshold resonances in the e+-He+ system using the stabilization method in the framework of hyperspherical coordinates (HSSM). A narrow resonance at Er = -0.249995 with width r = 1.9 x 10-5, associated with the He2+-Ps(n = 1) threshold is confirmed. The resonances around the energies -0.365 and -0.195, predicted by Bhatia and Drachman [Phys. Rev. A 42(1990)5117] and confirmed by Ho [Phys. Rev. A 53 (1996) 3165], do not appear in our calculations.

  10. Narrow deeply bound K- and p atomic states

    Science.gov (United States)

    Friedman, E.; Gal, A.

    2000-01-01

    Examples of recently predicted narrow `deeply bound' K- and p atomic states are shown. The saturation of widths for strong absorptive potentials due to the induced repulsion, and the resulting suppression of atomic wave functions within the nucleus, are demonstrated. Production reactions for K- atomic states using φ(1020) decay, and the (p,p) reaction for p atomic states, are discussed.

  11. Stationary phases for superheated water chromatography

    CERN Document Server

    Saha, S

    2002-01-01

    This project focused on the comparison of conventional liquid chromatography and superheated water chromatography. It examined the differences in efficiency and retention of a range of different stationary phases. Alkyl aryl ketones and eight aromatic compounds were separated on PBD-zirconia, Xterra RP 18, Luna C sub 1 sub 8 (2) and Oasis HLB columns using conventional LC and superheated water chromatography system. The retention indices were determined in the different eluents. On changing the organic component of the eluent from methanol to acetonitrile to superheated water considerable improvements were found in the peak shapes and column efficiencies on the PBD-zirconia and Oasis HLB columns. PS-DVB, PBD-zirconia and Xterra RP 18 columns have been used in efficiency studies. It was found that simply elevating the column temperature did not increase the efficiency of a separation in superheated water chromatography. The efficiency depended on flow rate, injection volume and also mobile phase preheating sys...

  12. Phase Diagram of Iron, Revised-Core Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ahrens, T.J.; Chen, G.Q.; Holland, K.G.

    1999-01-27

    Shock-wave experiments on iron preheated to 1,573 K conducted from 14 to 73 GPa, yield new data for sound velocities of the {gamma}- and liquid-phases. Melting was observed in the highest pressure ({approximately} 71 {+-} 2 GPa) experiments at calculated shock temperatures of 2,775 {+-} 160 K. This single crossing of the {gamma}-liquid boundary measured here agrees closely with the {gamma}-iron melting line determined by Boehler [1993], Saxena et al. [1993], and Jephcoat and Besedin [1997]. This {gamma}-iron melting curve is {approximately} 300 C lower than that of Shen et al. [1998b] at 80 GPa.

  13. The narrow and moving HeII lines in nova KT Eri

    CERN Document Server

    Munari, U; Valisa, P

    2014-01-01

    We present outburst and quiescence spectra of the classical nova KT Eri and discuss the appearance of a sharp HeII 4686 Ang emission line, whose origin is a matter of discussion for those novae that showed a similar component. We suggest that the sharp HeII line, when it first appeared toward the end of the outburst optically thick phase, comes from the wrist of the dumbbell structure characterizing the ejecta as modeled by Ribeiro et al. (2013). When the ejecta turned optically thin, the already sharp HeII line became two times narrower and originated from the exposed central binary. During the optically thin phase, the HeII line displayed a large change in radial velocity that had no counterpart in the Balmer lines (both their narrow cores and the broad pedestals). The large variability in radial velocity of the HeII line continued well into quiescence, and it remains the strongest emission line observed over the whole optical range.

  14. Alternative approach to precision narrow-angle astrometry for Antarctic long baseline interferometry

    CERN Document Server

    Kok, Y; Rizzuto, A C; Tuthill, P G; Robertson, J G; Warrington, B A; Tango, W J

    2014-01-01

    The conventional approach to high-precision narrow-angle astrometry using a long baseline interferometer is to directly measure the fringe packet separation of a target and a nearby reference star. This is done by means of a technique known as phase-referencing which requires a network of dual beam combiners and laser metrology systems. Using an alternative approach that does not rely on phase-referencing, the narrow-angle astrometry of several closed binary stars (with separation less than 2$"$), as described in this paper, was carried out by observing the fringe packet crossing event of the binary systems. Such an event occurs twice every sidereal day when the line joining the two stars of the binary is is perpendicular to the projected baseline of the interferometer. Observation of these events is well suited for an interferometer in Antarctica. Proof of concept observations were carried out at the Sydney University Stellar Interferometer (SUSI) with targets selected according to its geographical location....

  15. Frontal Plane Modelling of Human Dynamics during Standing in Narrow-Stance

    Science.gov (United States)

    Sonobe, M.; Yamaguchi, H.; Hino, J.

    2016-09-01

    Standing ride type vehicles like electric skateboards have been developed in recent years. Although these vehicles have advantages as being compact and low cost due to their simple structure, it is necessary to improve the riding quality. Therefore, the system aiding riders to keep their balance on a skateboard by feedback control or feedforward control has been required. To achieve it, a human balance model should be built as simple as possible. In this study, we focus on the human balance modelling during standing when the support surface moves largely. We restricted the model on frontal plane and narrow stance because the restrictions allow us to assume single-degree-of-freedom model. The balance control system is generally assumed as a delayed feedback control system. The model was identified through impulse response test and frequency response test. As a result, we found the phase between acceleration of the skateboard and posture angle become opposite phase in low frequency range.

  16. Preheating System of Auxiliary Converter for Plateau Type HXD1C Locomotive%高原型HXD1C机车辅助变流器预加热系统

    Institute of Scientific and Technical Information of China (English)

    吴建雄; 陈湘; 钱勇亮

    2012-01-01

    阐述了高原型HXD1C机车辅助变流器预加热系统及逻辑控制过程,分析了选择加热电阻的方法、设计加热风道的方法以及安装传感器的方法,可为进一步确保辅助变流器在极低温环境下正常稳定运行提供参考。%It illustrated the preheating system of auxiliary converter for plateau type HXD1C locomotive and its logic control process.It analyzed the methods of selecting preheating resistance,designing air-channels and installing sensors,which provided important reference for ensuring that the auxiliary converter could run normally and steadily under the extreme cold condition.

  17. Experimental Study on Emission Control of Premixed Catalytic Combustion of Natural Gas Using Preheated Air%使用加热空气的预混天然气催化燃烧的实验研究

    Institute of Scientific and Technical Information of China (English)

    许考; 刘中良; 何洪; 程水源; 马重芳

    2007-01-01

    In this paper the premixed catalytic combustion emissions such as CO, unburned hydrocarbon (UHC),NOx and the temperature distribution in the catalytic monolith with ultra low concentration of Pd were studied.Three types of monoliths were used for experiments and the temperature of preheated air was respectively 50℃,100℃ and 200℃. The results showed that preheated air made radial temperature in the catalytic monolith uniform which helped to avoid local hot spots so as to decrease NOx emission. The experiment also proved that the shorter monolith showed much better catalytic combustion performance than longer one and the temperature at the exit of the shorter monolith was relatively lower. On the contrary, the temperature was higher in the longer monolith and the lethal NOx emission was slightly increased.

  18. Distribution of Hg, As and Se in material and flue gas streams from preheater-precalciner cement kilns and vertical shaft cement kilns in China.

    Science.gov (United States)

    Yan, Dahai; Peng, Zheng; Ding, Qiong; Karstensen, Kåre Helge; Engelsen, Christian J; Li, Li; Ren, Yong; Jiang, Chen

    2015-08-01

    The aim of this study was to evaluate the behavior of Hg, As, and Se in cement production. Two types of cement plants were studied, including the vertical shaft kiln (VSK) and preheater-precalciner kiln (PPK) processes. Determination of Hg, As, and Se in the main material and gas streams were performed. It was found that recycling of particulate matter captured by an air pollution control device caused a significant enrichment of Hg and As inside both processes. The total quantity of Hg entering the process and the quantity emitted to the atmosphere were found to be 10-109 and 6.3-38 mg, respectively, per ton of clinker produced. The average Hg emission was calculated to be around 41% of the total mercury input. The emissions found complied with the European Union (EU) limit and exceeded partly the U.S. limit. Furthermore, it was found that oxidized mercury was the dominant species in the PPK process, whereas the reduced form was dominant in the VSK process, due to the oxidizing and reducing gas conditions, respectively. Regarding the distribution of As and Se, the major amounts were bound to the solid materials, that is, cement clinker and particulate matter. Based on cement production data in China in 2013, the annual emissions of Hg and As were estimated to be in the range of 8.6-52 and 4.1-9.5 tons, respectively.

  19. Research of Infrared Preheating Vibration Friction Welding Technology for Plastic%塑料红外预加热振动摩擦焊接技术研究

    Institute of Scientific and Technical Information of China (English)

    刘勇; 李朝晖; 朱彩萍

    2012-01-01

    比较了红外预加热振动摩擦焊接技术即清洁摩擦焊接技术(CVT)相对于传统塑料焊接技术的优势,论述了CVT的原理,并对CVT的可行性和实际应用进行了分析.结果表明,CVT可大幅改善塑料焊接件的外观质量,减少焊接过程中的颗粒排放并提高其焊接强度,是一种清洁高效的新型塑料焊接技术.%Advantages of infrared preheating vibration friction welding technology which also was known as clean vibration friction welding technology ( CVT) were compared with traditional plastic welding technologies, and the theory of CVT was expounded, then the feasibility and practical application of CVT were analyzed. The results showed that CVT could improve the appearance quality of plastic welding parts substantially, decrease the participate emission during the welding process and increase the welding strength. It indicated that CVT was a new kind of plastic welding technology with clean and high efficiency.

  20. 采用感应预热的连续激光淬火%Continuous Laser Hardening with Induction Pre-Heating

    Institute of Scientific and Technical Information of China (English)

    I Doležel; V.Kotlan; R.Hamar; D.Pánek

    2015-01-01

    A novel way of continuous surface hardening of steel bodies by a laser beam is modeled.This heat treatment is supplemented with pre-heating of the hardened parts by a classic inductor in order to reduce the temperature gradients and subsequent mechanical stresses in the processed material.The mathematical model of the process is solved numerically in 3D and the solution respects all important nonlinearities (a saturation curve of the hardened steel and temperature dependences of its physical properties).The methodology is illustrated with a typical example,whose results are presented and discussed.%模拟了钢件采用激光束进行表面连续淬火的新方法。这种热处理方法采用传统的感应器对淬火零件进行预热,以便减小温度梯度及随后产生的被处理材料的机械应力。该工艺的数学模型采用3D数值建立,其解法考虑了所有重要的非线性特性(被淬火钢的磁饱和曲线及其物理性能与温度的关系)。用典型的实例进行了说明,介绍了结果并进行了讨论。

  1. Transfer of preheat-treated SnO 2 via a sacrificial bridge-type ZnO layer for ethanol gas sensor

    KAUST Repository

    Lee, Da Hoon

    2017-08-05

    The progress in developing the microelectromechanical system (MEMS) heater-based SnO2 gas sensors was hindered by the subsequent heat treatment of the tin oxide (SnO2), nevertheless it is required to obtain excellent sensor characteristics. During the sintering process, the MEMS heater and the contact electrodes can be degraded at such a high temperature, which could reduce the sensor response and reliability. In this research, we presented a process of preheating the printed SnO2 sensing layer on top of a sacrificial bridge-type ZnO layer at such a high temperature, followed by transferring it onto the contact electrodes of sensor device by selective etching of the sacrificial ZnO layer. Therefore, the sensor device was not exposed to the high sintering temperature. The SnO2 gas sensor fabricated by the transfer process exhibited a rectangular sensing curve behavior with a rapid response of 52 s at 20 ppm ethanol concentration. In addition, reliable and repeatable sensing characteristics were obtained even at an ethanol gas concentration of 5 ppm.

  2. Application of high strength sonic soot blower in air preheater of 1 000 MW units%高强声波吹灰器在1000 MW机组空预器中的应用

    Institute of Scientific and Technical Information of China (English)

    李彦民; 王俊杰

    2016-01-01

    There are some problems existed in the running of air preheater in CLP vote of Henan Electric Power co. LTD. ,Pingdingshan Power 2 x 1 000 MW ultra supercritical units. The air preheater had a large amount of dust ,so the resistance increased which is one of the important reasons affecting the safe and economic opera-tion. The sonic soot blower is applied in air preheater to prevent the dust and its effect is analyzed. The practi-cal application results show that the efficient acoustic wave sootblower are deposited in the air preheater and has obvious effect, the safety benefit, economic benefit and social benefit are remarkable.%介绍了中电投河南电力有限公司平顶山发电分公司2×1000 MW超超临界机组空预器在运行中出现的大量积灰情况,空预器阻力的大幅增加是影响机组安全、经济运行的重要原因。分析通过空预器加装声波吹灰器后对防止空预器大量积灰的效果,根据实践应用结果表明,高效声波吹灰器对空预器积灰有明显效果,安全效益、经济效益及社会效益显著。

  3. 350 MW超临界直流锅炉空预器堵塞原因分析及处理%Analysis and Treatment of Blockage in Air Preheater of 350 MW Supercritical Once Through Boiler

    Institute of Scientific and Technical Information of China (English)

    崔鹏

    2016-01-01

    The selective catalytic reduction (SCR) by reducing agent of ammonia (NH3) is used to achieve the purpose of removal of NOx in flue gas in boiler denitration system in Hohhot Thermal Power Plant. In the operation of ammonia and NOx cannot all mix, escape is inevitable, when the escape rate of overweight ammonia and sulfur trioxide in flue gas reaction generated hydrogen sulfate ammonia block in air preheater, due to differential pressure increasing of the air preheater. The application of ammonium hydrogen sulfate physical properties will be ammonia decomposition hydrogen sulfate, air preheater body heat will ammonia gasification hydrogen sulfate, eliminating air preheater clogging. Experience can be used as reference in the same type unit.%呼和浩特热电厂2×350 MW机组锅炉脱硝系统采取选择性催化还原法(SCR),使用还原剂氨(NH3)来达到除去烟气中NOx的目的。运行中氨气和NOx不可能全部混合,逃逸无法避免,当逃逸率超标时,氨气与烟气中三氧化硫反应生成硫酸氢铵堵塞空预器,导致空预器前后差压增大。对此根据硫酸氢铵的物理性质,采用空预器降风量升烟温的方法将硫酸氢铵气化,消除空预器堵塞,经验可供同类型机组参考。

  4. 带废钢预热电弧炉烟气中的二(口恶)英的产生及抑制%The Dioxin Producing and Restraint in Fume from EAF during Scrap Preheat

    Institute of Scientific and Technical Information of China (English)

    侯祥松

    2011-01-01

    The dioxin producing mechanism in EAF, especially the dioxin producing mechanism in EAF with scrap preheat is analyzed. It is shown that the scrap preheat will induce significant increment of dioxin in the fume. Some special methods should be adopted during design as scrap sorting controlling the fume temperature after scrap preheat, spraying lime, quickening cooling velocity in waste heat boiler. The dioxin deprivation device is necessary sometimes in order to satisfy the criteria.%介绍了电炉炼钢烟气中二(口恶)英的产生机理,特别介绍其废钢预热系统将使其烟气中二(口恶)英浓度显著增加的成因,提出了带废钢预热的电炉炼钢时,应充分考虑采取废钢的分选净化、烟气有效收集和采用除脱设备等措施,特别是采用控制预热后烟气温度、喷石灰、加快余热锅炉冷却速度等合理的工艺及技术,以抑制电炉炼钢烟气中二(口恶)英的持续生成.

  5. 煤气锅炉空气预热器腐蚀原因及对策%Reason and Treatment of Air Preheater Corrosion of Gas-Fired Boiler

    Institute of Scientific and Technical Information of China (English)

    王锐; 刘启学; 孙保顺

    2013-01-01

    结合对75t煤气锅炉低温段空气预热器的改造实例,阐述了煤气锅炉低温段空气预热器因锅炉负荷变化、掺烧焦炉煤气增大等因素而引起的低温段空气预热器低温腐蚀现象,分析了低温段空气预热器腐蚀损坏的原因并提出了相应的预防改进措施。%Combine a instance of the remould to the air preheater of the 75 t gas-fired boiler low temperature segment in Xingtai Iron& Steel Corp .Ltd., describe the actualities of air preheater corrosion of gas-fired boiler be-cause of the boiler load carries change and coke-oven gas flow enlarged etc ..Reasons of air preheater corrosion was an-alyzed, and the solution measures are proposed .

  6. Narrow linewidth emissions from organic crystals with diffraction gratings engraved directly on their surface (Conference Presentation)

    Science.gov (United States)

    Yamamoto, Hiroyuki; Yamao, Takeshi; Hotta, Shu

    2016-10-01

    In combination with optical cavities, organic semiconductor crystals are powerful candidates for current-injected organic laser devices. For such cavities diffraction gratings are applicable. In common with external diffraction gratings made of dielectrics and oxides, built-in ones are effective for producing narrow linewidth emissions. However, direct fabrication of the diffraction gratings on the surfaces of the organic crystals is still challenging. In the present studies, we directly engraved one-dimensional (1D) diffraction gratings on the flat surfaces of organic semiconductor crystals by using focused ion beam (FIB) lithography, and shaped a distributed feedback resonator (DFB) structure. We chose as the organic semiconductor material 5,5'''''-diphenyl-2,2':5',2'':5'',2''':5''',2'''':5'''',2'''''-sexithiophene (P6T) from among thiophene/phenylene co-oligomers. We grew plate-like crystals of P6T in a vapor phase. The P6T crystals showed emissions with a maximum intensity around 630 nm. We laminated them on Si wafer substrates covered with 300-nm-thick silicon dioxide and 160-nm-thick Al-doped ZnO (AZO) layers. The AZO layer was used to prevent the crystals from being charged during the FIB lithography. We precisely controlled FIB process conditions and obtained the gratings having the equally-spaced 200 (400) grooves with the periods of 240 (200) nm. When we observed the emissions perpendicular to the grating grooves as well as parallel to the crystal surface under ultraviolet light from a mercury lamp, these crystals with the 1D diffraction gratings indicated narrowed emission peaks at 745 (670) nm. From the grating period and the emission peak position, we estimated an order of diffraction and an effective refractive index. We related the effective refractive index with a phase refractive index of the crystal and decided the optimum grating period to be 190 nm to produce the narrowed peak at 630 nm. We fabricated the diffraction grating having the optimum

  7. Period effects, cohort effects, and the narrowing gender wage gap.

    Science.gov (United States)

    Campbell, Colin; Pearlman, Jessica

    2013-11-01

    Despite the abundance of sociological research on the gender wage gap, questions remain. In particular, the role of cohorts is under investigated. Using data from the Current Population Survey, we use age-period-cohort analysis to uniquely estimate age, period, and cohort effects on the gender wage gap. The narrowing of the gender wage gap that occurred between 1975 and 2009 is largely due to cohort effects. Since the mid-1990s, the gender wage gap has continued to close absent of period effects. While gains in female wages contributed to declines in the gender wage gap for cohorts born before 1950, for later cohorts the narrowing of the gender wage gap is primarily a result of declines in male wages.

  8. Model of Layered Weld Formation Under Narrow Gap Pulse Welding

    Science.gov (United States)

    Krampit, A. G.

    2016-04-01

    The model parameters of narrow gap pulse welding can be divided into input, internal and output ones. The breadth of gap, that is, clearance breadth between upright edges is one of key parameters securing high quality of a weld joint. The paper presents theoretical outcomes for the model of layered weld formation under narrow gap pulse welding. Based on these studies is developed model of processes, which occur in the weld pool under pulse grove welding. It comprises the scheme of liquid metal motion in the weld pool, scheme of fusion with the side edge and in the bottom part, and the scheme of welding current impulse effect on the structure of a weld joint.

  9. Subwavelength-Sized Narrow-Band Anechoic Waveguide Terminations

    Science.gov (United States)

    Santillán, Arturo; Ćrenlund, Emil; Bozhevolnyi, Sergey I.

    2016-11-01

    We propose and demonstrate the use of a pair of detuned acoustic resonators to efficiently absorb narrow-band sound waves in a terminated waveguide. The suggested configuration is relatively simple and advantageous for usage at low frequencies, since the dimensions of the resonators are very small compared to the wavelength. We present a theoretical description based on lumped parameters to calculate the absorption coefficient, which agrees very well with experimental data. The experimental results verify that the anechoic (reflection approximately -38 dB ) narrow-band (Δ f /f ˜0.1 ) termination with deeply subwavelength (sound absorption in a room, we demonstrate by use of numerical simulations that a given axial resonant excitation in a room can be practically eliminated. Thus, a reduction of approximately 24 dB in the average acoustic energy is achieved in the room when using only four Helmholtz resonators. We also discuss various scenarios of noise control in rooms.

  10. Motional narrowing of broadband absorption of solvatochromic indicator Betaine 30

    Energy Technology Data Exchange (ETDEWEB)

    Renge, Indrek [Institute of Physics, University of Tartu, Riia Street 142, EE51014 Tartu (Estonia)], E-mail: indrek.renge@ut.ee

    2009-05-15

    Temperature dependence of the absorption spectra of Betaine 30 (2,6-diphenyl-4-(2,4,6-triphenylpyridinio)-phenolate, widely known as Reichardt's dye) is compared with that of the broadband spectra of other dyes. The double value of the half-width (2 hwhm) of Betaine 30 absorption band between 10 and 293 K in a polymer decreases by 130{+-}20 cm{sup -1}, from 4220 to 4090 cm{sup -1}. This unprecedented narrowing with increasing temperature is ascribed to hydrogen bond symmetrization due to thermally activated proton tunneling in a pigment-solvent complex. The averaging of charge distribution along the proton coordinate causes motional narrowing of inhomogeneous width.

  11. Bandgap narrowing in moderately to heavily doped silicon

    Science.gov (United States)

    Lanyon, H. P. D.; Tuft, R. A.

    1979-01-01

    A theoretical model of bandgap narrowing in silicon at high doping levels has been developed. The model takes into account the electrostatic energy of interaction between a minority carrier and the majority carriers surrounding it, which reduces the thermal energy necessary for creation of an electron-hole pair. A pair energy similar to the excitonic binding energy of bound electron-hole pairs in insulators is obtained. Theoretical results are in excellent agreement with experimental results in the doping range from 3 times 10 to the 17th to 1.5 times 10 to the 20th/cu cm at room temperature. These results indicate that at high injection levels such as a transistor biased into the conductivity-modulation regime or a solar cell whose surface is established by ion implantation into an oxide layer, the bandgap narrowing is determined by the injected carrier concentration rather than by the doping level.

  12. Coulomb and nuclear excitations of narrow resonances in 17Ne

    Directory of Open Access Journals (Sweden)

    J. Marganiec

    2016-08-01

    Full Text Available New experimental data for dissociation of relativistic 17Ne projectiles incident on targets of lead, carbon, and polyethylene targets at GSI are presented. Special attention is paid to the excitation and decay of narrow resonant states in 17Ne. Distributions of internal energy in the O15+p+p three-body system have been determined together with angular and partial-energy correlations between the decay products in different energy regions. The analysis was done using existing experimental data on 17Ne and its mirror nucleus 17N. The isobaric multiplet mass equation is used for assignment of observed resonances and their spins and parities. A combination of data from the heavy and light targets yielded cross sections and transition probabilities for the Coulomb excitations of the narrow resonant states. The resulting transition probabilities provide information relevant for a better understanding of the 17Ne structure.

  13. Experimental research on flow instability in vertical narrow annuli

    Institute of Scientific and Technical Information of China (English)

    WU Geping; QIU Suizheng; SU Guanghui; JIA Dounan

    2007-01-01

    A narrow annular test section of 1.5mm gap and 1800mm length was designed and manufactured, with good tightness and insulation. Experiments were carried out to investigate characteristics of flow instability of forced-convection in vertical narrow annuli. Using distilled water as work fluid, the experiments were conducted at pressures of 1.0~3.0 MPa, mass flow rates of 3.0~25 kg/h, heating power of 3.0~ 6.5kW and inlet fluid temperature of 20 ℃, 40 ℃ or 60℃. It was found that flow instability occured with fixed inlet condition and heating power when mass flow rate was below a special value. Effects of inlet subcooling, system pressure and mass flow rate on the system behavior were studied and the instability region was given.

  14. Search for narrow vector resonances in the Z mass range

    Science.gov (United States)

    Adriani, O.; Aguilar-Benitez, M.; Ahlen, S.; Alcaraz, J.; Aloisio, A.; Alverson, G.; Alviggi, M. G.; Ambrosi, G.; An, Q.; Anderhub, H.; Anderson, A. L.; Andreev, V. P.; Antonov, L.; Antreasyan, D.; Arce, P.; Arefiev, A.; Atamanchuk, A.; Azemoon, T.; Aziz, T.; Baba, P. V. K. S.; Bachmann, S.; Bagnaia, P.; Bakken, J. A.; Baksay, L.; Ball, R. C.; Banerjee, S.; Bao, J.; Barillère, R.; Barone, L.; Baschirotto, A.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Behrens, J.; Bencze, Gy. L.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B. L.; Biasini, M.; Biland, A.; Bilei, G. M.; Bizzarri, R.; Blaising, J. J.; Bobbink, G. J.; Bock, R.; Böhm, A.; Borgia, B.; Bosetti, M.; Bourilkov, D.; Bourquin, M.; Boutigny, D.; Bouwens, B.; Brambilla, E.; Branson, J. G.; Brock, I. C.; Brooks, M.; Bujak, A.; Burger, J. D.; Burger, W. J.; Busenitz, J.; Buytenhuijs, A.; Cai, X. D.; Capell, M.; Caria, M.; Carlino, G.; Cartacci, A. M.; Castello, R.; Cerrada, M.; Cesaroni, F.; Chang, Y. H.; Chaturvedi, U. K.; Chemarin, M.; Chen, A.; Chen, C.; Chen, G. M.; Chen, H. F.; Chen, H. S.; Chen, M.; Chen, W. Y.; Chiefari, G.; Chien, C. Y.; Choi, M. T.; Chung, S.; Civinini, C.; Clare, I.; Clare, R.; Coan, T. E.; Cohn, H. O.; Coignet, G.; Colino, N.; Contin, A.; Cui, X. T.; Cui, X. Y.; Dai, T. S.; D'Alessandro, R.; de Asmundis, R.; Degré, A.; Deiters, K.; Dénes, E.; Denes, P.; DeNotaristefani, F.; Dhina, M.; DiBitonto, D.; Diemoz, M.; Dimitrov, H. R.; Dionisi, C.; Djambazov, L.; Dova, M. T.; Drago, E.; Duchesneau, D.; Duinker, P.; Duran, I.; Easo, S.; El Mamouni, H.; Engler, A.; Eppling, F. J.; Erné, F. C.; Extermann, P.; Fabbretti, R.; Fabre, M.; Falciano, S.; Fan, S. J.; Fackler, O.; Fay, J.; Felcini, M.; Ferguson, T.; Fernandez, D.; Fernandez, G.; Ferroni, F.; Fesefeldt, H.; Fiandrini, E.; Field, J.; Filthaut, F.; Finocchiaro, G.; Fisher, P. H.; Forconi, G.; Foreman, T.; Freudenreich, K.; Friebel, W.; Fukushima, M.; Gailloud, M.; Galaktionov, Yu.; Gallo, E.; Ganguli, S. N.; Garcia-Abia, P.; Gele, D.; Gentile, S.; Goldfarb, S.; Gong, Z. F.; Gonzalez, E.; Gougas, A.; Goujon, D.; Gratta, G.; Gruenewald, M.; Gu, C.; Guanziroli, M.; Guo, J. K.; Gupta, V. K.; Gurtu, A.; Gustafson, H. R.; Gutay, L. J.; Hangarter, K.; Hasan, A.; Hauschildt, D.; He, C. F.; He, J. T.; Hebbeker, T.; Hebert, M.; Herten, G.; Hervé, A.; Hilgers, K.; Hofer, H.; Hoorani, H.; Hu, G.; Hu, G. Q.; Ille, B.; Ilyas, M. M.; Innocente, V.; Janssen, H.; Jezequel, S.; Jin, B. N.; Jones, L. W.; Kasser, A.; Khan, R. A.; Kamyshkov, Yu.; Kapinos, P.; Kapustinsky, J. S.; Karyotakis, Y.; Kaur, M.; Khokhar, S.; Kienzle-Focacci, M. N.; Kim, J. K.; Kim, S. C.; Kim, Y. G.; Kinnison, W. W.; Kirkby, D.; Kirsch, S.; Kittel, W.; Klimentov, A.; König, A. C.; Koffeman, E.; Kornadt, O.; Koutsenko, V.; Koulbardis, A.; Kraemer, R. W.; Kramer, T.; Krastev, V. R.; Krenz, W.; Krivshich, A.; Kuijten, H.; Kumar, K. S.; Kunin, A.; Landi, G.; Lanske, D.; Lanzano, S.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Lee, D. M.; Leedom, I.; Leggett, C.; Le Goff, J. M.; Leiste, R.; Lenti, M.; Leonardi, E.; Leytens, X.; Li, C.; Li, H. T.; Li, P. J.; Liao, J. Y.; Lin, W. T.; Lin, Z. Y.; Linde, F. L.; Lindemann, B.; Lista, L.; Liu, Y.; Lohmann, W.; Longo, E.; Lu, Y. S.; Lubbers, J. M.; Lübelsmeyer, K.; Luci, C.; Luckey, D.; Ludovici, L.; Luminari, L.; Lustermann, W.; Ma, J. M.; Ma, W. G.; MacDermott, M.; Malhotra, P. K.; Malik, R.; Malinin, A.; Maña, C.; Maolinbay, M.; Marchesini, P.; Marion, F.; Marin, A.; Martin, J. P.; Martinez-Laso, L.; Marzano, F.; Massaro, G. G. G.; Mazumdar, K.; McBride, P.; McMahon, T.; McNally, D.; Merk, M.; Merola, L.; Meschini, M.; Metzger, W. J.; Mi, Y.; Mills, G. B.; Mir, Y.; Mirabelli, G.; Mnich, J.; Möller, M.; Monteleoni, B.; Morand, R.; Morganti, S.; Moulai, N. E.; Mount, R.; Müller, S.; Nadtochy, A.; Nagy, E.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Neyer, C.; Niaz, M. A.; Nippe, A.; Nowak, H.; Organtini, G.; Pandoulas, D.; Paoletti, S.; Paolucci, P.; Pascala, G.; Passaleva, G.; Patricelli, S.; Paul, T.; Pauluzzi, M.; Paus, C.; Pauss, F.; Pei, Y. J.; Pensotti, S.; Perret-Gallix, D.; Perrier, J.; Pevsner, A.; Piccolo, D.; Pieri, M.; Piroué, P. A.; Plasil, F.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Postema, H.; Qi, Z. D.; Qian, J. M.; Qureshi, K. N.; Raghavan, R.; Rahal-Callot, G.; Rancoita, P. G.; Rattaggi, M.; Raven, G.; Razis, P.; Read, K.; Ren, D.; Ren, Z.; Rescigno, M.; Reucroft, S.; Ricker, A.; Riemann, S.; Riemers, B. C.; Riles, K.; Rind, O.; Rizvi, H. A.; Rodriguez, F. J.; Roe, B. P.; Röhner, M.; Röhner, S.; Romero, L.; Rose, J.; Rosier-Lees, S.; Rosmalen, R.; Rosselet, Ph.; van Rossum, W.; Roth, S.; Rubbia, A.; Rubio, J. A.; Rykaczewski, H.; Sachwitz, M.; Salicio, J.; Salicio, J. M.; Sanders, G. S.; Santocchia, A.; Sarakinos, M. S.; Sartorelli, G.; Sassowsky, M.; Sauvage, G.; Schäfer, C.; Schegelsky, V.; Schmitz, D.; Schmitz, P.; Schneegans, M.; Schopper, H.; Schotanus, D. J.; Shotkin, S.; Schreiber, H. J.; Shukla, J.; Schulte, R.; Schulte, S.; Schultze, K.; Schwenke, J.; Schwering, G.; Sciacca, C.; Scott, I.; Sehgal, R.; Seiler, P. G.; Sens, J. C.; Servoli, L.; Sheer, I.; Shen, D. Z.; Shevchenko, S.; Shi, X. R.; Shumilov, E.; Shoutko, V.; Son, D.; Sopczak, A.; Spartiotis, C.; Spickermann, T.; Spillantini, P.; Starosta, R.; Steuer, M.; Stickland, D. P.; Sticozzi, F.; Stone, H.; Strauch, K.; Stringfellow, B. C.; Sudhakar, K.; Sultanov, G.; Sun, L. Z.; Suter, H.; Swain, J. D.; Syed, A. A.; Tang, X. W.; Taylor, L.; Terzi, G.; Ting, Samuel C. C.; Ting, S. M.; Tonutti, M.; Tonwar, S. C.; Tóth, J.; Tsaregorodtsev, A.; Tsipolitis, G.; Tully, C.; Tung, K. L.; Ulbricht, J.; Urbán, L.; Uwer, U.; Valente, E.; Van de Walle, R. T.; Vetlitsky, I.; Viertel, G.; Vikas, P.; Vikas, U.; Vivargent, M.; Vogel, H.; Vogt, H.; Vorobiev, I.; Vorobyov, A. A.; Vuilleumier, L.; Wadhwa, M.; Wallraff, W.; Wang, C.; Wang, C. R.; Wang, G. H.; Wang, X. L.; Wang, Y. F.; Wang, Z. M.; Weber, A.; Weber, J.; Weill, R.; Wenaus, T. J.; Wenninger, J.; White, M.; Willmott, C.; Wittgenstein, F.; Wright, D.; Wu, S. X.; Wynhoff, S.; Wysłouch, B.; Xie, Y. Y.; Xu, J. G.; Xu, Z. Z.; Xue, Z. L.; Yan, D. S.; Yang, B. Z.; Yang, C. G.; Yang, G.; Ye, C. H.; Ye, J. B.; Ye, Q.; Yeh, S. C.; Yin, Z. W.; You, J. M.; Yunus, N.; Yzerman, M.; Zaccardelli, C.; Zemp, P.; Zeng, M.; Zeng, Y.; Zhang, D. H.; Zhang, Z. P.; Zhou, B.; Zhou, G. J.; Zhou, J. F.; Zhu, R. Y.; Zichichi, A.; van der Zwaan, B. C. C.; L3 Collaboration

    1993-08-01

    The hadronic lineshape of the Z has been analyzed for evidence of signals of new, narrow vector resonances in the Z-mass range. The production rate of such resonances would be enhanced due to mixing with the Z. No evidence for new states is found, and it is thus possible to exclude, at the 95% confidence level, a quarkonium state in the mass range from 87.7 to 94.7 GeV.

  15. Whispering Gallery Mode Resonator Stabilized Narrow Linewidth Fiber Loop Laser

    CERN Document Server

    Sprenger, B; Wang, L J; 10.1364/OL.34.003370

    2012-01-01

    We demonstrate a narrow line, fiber loop laser using Erbium-doped fiber as the gain material, stabilized by using a microsphere as a transmissive frequency selective element. Stable lasing with a linewidth of 170 kHz is observed, limited by the experimental spectral resolution. A linear increase in output power and a red-shift of the lasing mode were also observed with increasing pump power. Its potential application is also discussed.

  16. Analysis of ultra-narrow ferromagnetic domain walls

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, Catherine; Paul, David

    2012-01-10

    New materials with high magnetic anisotropy will have domains separated by ultra-narrow ferromagnetic walls with widths on the order of a few unit cells, approaching the limit where the elastic continuum approximation often used in micromagnetic simulations is accurate. The limits of this approximation are explored, and the static and dynamic interactions with intrinsic crystalline defects and external driving elds are modeled. The results developed here will be important when considering the stability of ultra-high-density storage media.

  17. Three-Prong Distribution of Massive Narrow QCD Jets

    CERN Document Server

    Field, Matan; Kosower, David A; Mannelli, Lorenzo; Perez, Gilad

    2013-01-01

    We study the planar-flow distributions of narrow, highly boosted, massive QCD jets. Using the factorization properties of QCD in the collinear limit, we compute the planar-flow jet function from the one-to-three splitting function at tree-level. We derive the leading-log behavior of the jet function analytically. We also compare our semi-analytic jet function with parton-shower predictions using various generators.

  18. Cervical spinal canal narrowing and cervical neurologi-cal injuries

    Directory of Open Access Journals (Sweden)

    ZHANG Ling

    2012-04-01

    Full Text Available 【Abstract】Cervical spinal canal narrowing can lead to injury of the spinal cord and neurological symptoms in-cluding neck pain, headache, weakness and parasthesisas. According to previous and recent clinical researches, we investigated the geometric parameters of normal cervical spinal canal including the sagittal and transverse diameters as well as Torg ratio. The mean sagittal diameter of cervical spinal canal at C 1 to C 7 ranges from 15.33 mm to 20.46 mm, the mean transverse diameter at the same levels ranges from 24.45 mm to 27.00 mm and the mean value of Torg ratio is 0.96. With respect to narrow cervical spinal canal, the following charaterstics are found: firstly, extension of the cervical spine results in statistically significant stenosis as compared with the flexed or neutral positions; secondly, females sustain cervical spinal canal narrowing more easily than males; finally, the consistent narrowest cervical canal level is at C 4 for all ethnicity, but there is a slight variation in the sagittal diameter of cervical spinal stenosis (≤14 mm in Whites, ≤ 12 mm in Japanese, ≤13.7 mm in Chinese. Narrow sagittal cervical canal diameter brings about an increased risk of neurological injuries in traumatic, degenerative and inflam-matory conditions and is related with extension of cervical spine, gender, as well as ethnicity. It is hoped that this re-view will be helpful in diagnosing spinal cord and neuro-logical injuries with the geometric parameters of cervical spine in the future. Key words: Spinal cord injuries; Spinal stenosis; Trauma, nervous system

  19. Cervical spinal canal narrowing and cervical neurological injuries

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ling; CHEN Hai-bin; WANG Yi; ZHANG Li-ying; LIU Jing-cheng; WANG Zheng-guo

    2012-01-01

    Cervical spinal canal narrowing can lead to injury of the spinal cord and neurological symptoms including neck pain,headache,weakness and parasthesisas.According to previous and recent clinical researches,we investigated the geometric parameters of normal cervical spinal canal including the sagittal and transverse diameters as well as Torg ratio.The mean sagittal diameter of cervical spinal canal at C1 to C7 ranges from 15.33 mm to 20.46 mm,the mean transverse diameter at the same levels ranges from 24.45 mm to 27.00 mm and the mean value of Torg ratio is 0.96.With respect to narrow cervical spinal canal,the following charaterstics are found:firstly,extension of the cervical spine results in statistically significant stenosis as compared with the flexed or neutral positions; secondly,females sustain cervical spinal canal narrowing more easily than males;finally,the consistent narrowest cervical canal level is at C4 for all ethnicity,but there is a slight variation in the sagittal diameter of cervical spinal stenosis(≤ 14 mm in Whites,≤12 mm in Japanese,≤ 13.7 mm in Chinese).Narrow sagittal cervical canal diameter brings about an increased risk of neurological injuries in traumatic,degenerative and inflammatory conditions and is related with extension of cervical spine,gender,as well as ethnicity.It is hoped that this review will be helpful in diagnosing spinal cord and neurological injuries with the geometric parameters of cervical spine in the future.

  20. Photoluminescence from narrow InAs-AlSb quantum wells

    Science.gov (United States)

    Brar, Berinder; Kroemer, Herbert; Ibbetson, James; English, John H.

    1993-01-01

    We report on photoluminescence spectra from narrow InAs-AlSb quantum wells. Strong, clearly resolved peaks for well widths from 2 to 8 monolayers were observed. Transmission electron micrographs show direct evidence for the structural quality of the quantum well structures. The transition energies of the narrowest wells suggest a strong influence of the AlSb X-barrier on the electronic states in the conduction band.

  1. A numerical study of natural convection in a narrow annulus

    Energy Technology Data Exchange (ETDEWEB)

    Sahai, V.

    1991-12-01

    Various numerical models were used to predict the natural convection of a solidifying liquid metal in a narrow annulus. Previous work in this area do not consider the temperature variation that exists in the fluid and the resulting heat conduction in the solid mold material. The finite element fluid dynamics code FIDAP was sued to solve these models. The results indicate that the natural convective effects are small. 6 refs.

  2. A numerical study of natural convection in a narrow annulus

    Science.gov (United States)

    Sahai, V.

    1991-12-01

    Various numerical models were used to predict the natural convection of a solidifying liquid metal in a narrow annulus. Previous work in this area does not consider the temperature variation that exists in the fluid and the resulting heat conduction in the solid mold material. The finite element fluid dynamics code FIDAP was used to solve these models. The results indicate that the natural convective effects are small.

  3. Generation of narrow peaks in spectroscopy of charged particles

    Science.gov (United States)

    Dubbers, Dirk; Schmidt, Ulrich

    2016-11-01

    In spectroscopy of charged particles, narrow peaks may appear in continuous spectra if magnetic transport of the particles is involved. These artefacts, which so far have escaped the attention of investigators, can develop whenever geometric detection efficiency is less than 100%. As such peaks may be misinterpreted as new physics, their generation is investigated, both analytically and experimentally, for various detector configurations, including those used in searches for the spontaneous decay of the vacuum in heavy-ion collisions.

  4. Critical Heat Flux in Inclined Rectangular Narrow Gaps

    Energy Technology Data Exchange (ETDEWEB)

    Jeong J. Kim; Yong H. Kim; Seong J. Kim; Sang W. Noh; Kune Y. Suh; Joy L. Rempe; Fan-Bill Cheung; Sang B. Kim

    2004-06-01

    In light of the TMI-2 accident, in which the reactor vessel lower head survived the attack by molten core material, the in-vessel retention strategy was suggested to benefit from cooling the debris through a gap between the lower head and the core material. The GAMMA 1D (Gap Apparatus Mitigating Melt Attack One Dimensional) tests were conducted to investigate the critical heat flux (CHF) in narrow gaps with varying surface orientations. The CHF in an inclined gap, especially in case of the downward-facing narrow gap, is dictated by bubble behavior because the departing bubbles are squeezed. The orientation angle affects the bubble layer and escape of the bubbles from the narrow gap. The test parameters include gap sizes of 1, 2, 5 and 10 mm and the open periphery, and the orientation angles range from the fully downward-facing (180o) to the vertical (90o) position. The 15 ×35 mm copper test section was electrically heated by the thin film resistor on the back. The heater assembly was installed to the tip of the rotating arm in the heated water pool at the atmospheric pressure. The bubble behavior was photographed utilizing a high-speed camera through the Pyrex glass spacer. It was observed that the CHF decreased as the surface inclination angle increased and as the gap size decreased in most of the cases. However, the opposing results were obtained at certain surface orientations and gap sizes. Transition angles, at which the CHF changed in a rapid slope, were also detected, which is consistent with the existing literature. A semi-empirical CHF correlation was developed for the inclined narrow rectangular channels through dimensional analysis. The correlation provides with best-estimate CHF values for realistically assessing the thermal margin to failure of the lower head during a severe accident involving relocation of the core material.

  5. [Ventricular tachycardia with narrow QRS complex after cardiac surgery].

    Science.gov (United States)

    Nagajewski, Adam; Morskaya, Marina; Zembala, Marian

    2010-04-01

    We present new-onset sustained monomorphic ventricular tachycardia with relatively narrow QRS (width of QRS feminine 120 ms) in the recovery period after aortic valve replacement and surgical revascularisation in a patient with a prior inferior wall myocardial infarction. Ventricular tachycardia probably originating from the left-side His-Purkinje system and mimicking idiopathic posterior fascicular tachycardia was diagnosed. Placement of a bypass graft across occluded artery supplying an infarct zone was a potential trigger of this arrhythmia.

  6. Voicing Strategies Employed in Narrow Listening Among Iranian Female Freshmen

    OpenAIRE

    Mohsen Shahrokhi; Farinaz Shirani Bidabadi; Hamidah Yamat

    2013-01-01

    This study discusses the findings of a qualitative study on the strategies used by Iranian female freshmen in narrow listening. The data collected through semi-structured interview with 12 female freshmen (four learners as  advanced, four as intermediate and four as low) chosen purposefully based on their scores in the Oxford Placement Test administered. Six out of 12 freshmen were identified for the think-aloud protocol to draw out the strategies they used. The data collected were analyzed u...

  7. The Argument for a Narrow Conception of 'Religious Autonomy'

    DEFF Research Database (Denmark)

    Christoffersen, Lisbet

    2015-01-01

    This article argues for a both horizontal and vertical narrow concept of collective freedom of Religion. The most recent ECtHR judgments as well as the US Supreme Court Hosanna-Tabor case leads theory to establish religious autonomy based on parallel legal roders. Nordic theory has been based...... on lack of acknowledgement of Canon Law, which is no longer possible. A future path might be to accept overlapping normative orders, however with secular courts as the final institutions....

  8. Whittier Narrows Flood Control Basin Historic Resources Survey,

    Science.gov (United States)

    1976-10-15

    MAKING SURVEY 2.0 General In making this survey of the Whittier Narrows and Los Angeles River-Rio Hondo historic re- sources , the investigators have...various protective facilities. Washington provided the funds with the stipulation that the work be done unqr the direction of the United States Army Corps...testIfying to southern California’s historic penchant for unique town building ("Venice of America") and amusement park operation ( Disneyland ). Finally

  9. Joint Space Narrowing in Patients With Pisotriquetral Osteoarthritis.

    Science.gov (United States)

    Ten Berg, Paul W L; Heeg, Erik; Strackee, Simon D; Streekstra, Geert J

    2017-09-01

    Patients with suspected pisotriquetral osteoarthritis may show joint space narrowing. However, the extent of joint space narrowing and its deviation from the joint space width (JSW) in normal anatomy is unknown. In this pathoanatomic study, we therefore compared the JSW in the pisotriquetral joint between osteoarthritic patient wrists and healthy wrists. We reviewed preoperative computed tomography (CT) scans of 8 wrists of patients with ulnar-sided wrist pain who underwent a pisiformectomy with confirmed pisotriquetral osteoarthritis at surgery. We also reviewed CT scans of 20 normal wrists from healthy volunteers serving as control group. Three-dimensional CT models of the pisiform and triquetrum were obtained from both affected and normal wrists, after which the minimum JSW was calculated in an automated fashion. In the patient group, the median (interquartile range) of the minimum JSW was 0.1 mm (0.0-0.2), and in the control group, 0.8 mm (0.3-0.9) ( P = .007). We showed that the pisotriquetral joint space in osteoarthritic patient wrists was significantly narrowed compared with healthy wrists. These results suggest that JSW evaluation has a potential diagnostic value in the work-up of patients with suspected pisotriquetral osteoarthritis. This is an interesting area for future clinical research, especially because no gold standard for diagnosing pisotriquetral osteoarthritis has been established yet.

  10. Photonic bandgap narrowing in conical hollow core Bragg fibers

    Energy Technology Data Exchange (ETDEWEB)

    Ozturk, Fahri Emre; Yildirim, Adem; Kanik, Mehmet [UNAM-National Nanotechnology Research Center, Bilkent University, 06800 Ankara (Turkey); Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara (Turkey); Bayindir, Mehmet, E-mail: bayindir@nano.org.tr [UNAM-National Nanotechnology Research Center, Bilkent University, 06800 Ankara (Turkey); Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara (Turkey); Department of Physics, Bilkent University, 06800 Ankara (Turkey)

    2014-08-18

    We report the photonic bandgap engineering of Bragg fibers by controlling the thickness profile of the fiber during the thermal drawing. Conical hollow core Bragg fibers were produced by thermal drawing under a rapidly alternating load, which was applied by introducing steep changes to the fiber drawing speed. In conventional cylindrical Bragg fibers, light is guided by omnidirectional reflections from interior dielectric mirrors with a single quarter wave stack period. In conical fibers, the diameter reduction introduced a gradient of the quarter wave stack period along the length of the fiber. Therefore, the light guided within the fiber encountered slightly smaller dielectric layer thicknesses at each reflection, resulting in a progressive blueshift of the reflectance spectrum. As the reflectance spectrum shifts, longer wavelengths of the initial bandgap cease to be omnidirectionally reflected and exit through the cladding, which narrows the photonic bandgap. A narrow transmission bandwidth is particularly desirable in hollow waveguide mid-infrared sensing schemes, where broadband light is coupled to the fiber and the analyte vapor is introduced into the hollow core to measure infrared absorption. We carried out sensing simulations using the absorption spectrum of isopropyl alcohol vapor to demonstrate the importance of narrow bandgap fibers in chemical sensing applications.

  11. The Structure of Narrow-Line Region in LINERs

    Institute of Scientific and Technical Information of China (English)

    Hai-Feng Dai; Ting-Gui Wang

    2008-01-01

    Low-ionization nuclear emission regions (LINERs) are present in a large fraction of local galaxies, while their connection to the more luminous active galactic nuclei (AGN) remains elusive. We analyze the narrow band images obtained by the Hubble Space Telescope (HST) in Hα+[NⅡ] and/or [OⅢ] band for 23 LINERs and low luminosity Seyfert galaxies in the sample of the Palomar Optical Spectroscopic Survey of nearby galaxies in an attempt to resolve the structure of Narrow Emission Line Regions (NLRs) of these objects. In all cases, NLRs are well resolved and their morphology differs from object to object. Clumps, linear structure, spiral arms or a ring are detected in a large fraction of the objects, while there is no significant difference between Seyfert galaxies and LINERs. We find that the NLR size and the narrow line luminosity are strongly correlated for both LINERs and low luminosity Seyfert galaxies, and that the size of Hα+[NⅡ] emission line region scales with Hα luminosity as RNLR∞L0.4±0.06Hα, consistent with an extension of the NLR size-luminosity relation defined for luminous Seyfert galaxies and quasars, to two orders of magnitude lower in luminosity and to lower activity levels. Our results suggest that NLRs in LINERs are similar to those of Seyfert galaxies, and they are powered by the central active galactic nucleus.

  12. Study on dryout point in vertical narrow annuli

    Institute of Scientific and Technical Information of China (English)

    TIAN Wen-Xi; AYE Myint; QIU Sui-Zheng; JIA Dou-Nan

    2005-01-01

    Prediction of dryout point is experimentally investigated with deionized water upflowing through narrow annular channel with 1.0 mm and 1.5 mm gap respectively. The annulus with narrow gap is bilaterally heated by AC current power supply. The experimental conditions covered a range of pressure from 0.8 to 3.5 MPa, mass flux of 26.6 to 68.8 kg·m-2·s-1 and wall heat flux of 5 to 50 kW·m-2. The location of dryout is obtained by observing a sudden rise in surface temperature. Kutateladze correlation is cited and modified to predict the location of dryout and proved to be not a proper one. Considering in detail the effects of geometry of annuli, pressure, mass flux and heat flux on dryout, an empirical correction is finally developed to predict dryout point in narrow annular gap under low flow condition, which has a good agreement with experimental data.

  13. An experimental, theoretical and event-driven computational study of narrow vibrofluidised granular materials

    Science.gov (United States)

    Thornton, Anthony; Windows-Yule, Kit; Parker, David; Luding, Stefan

    2017-06-01

    We review simulations, experiments and a theoretical treatment of vertically vibrated granular media. The systems considered are confined in narrow quasi-two-dimensional and quasi-one-dimensional (column) geometries, where the vertical extension of the container is much larger than one or both horizontal lengths. The additional geometric constraint present in the column setup frustrates the convection state that is normally observed in wider geometries. We start by showing that the Event Driven (ED) simulation method is able to accurately reproduce the previously experimentally determined phase-diagram for vibrofludised granular materials. We then review two papers that used ED simulations to study narrow quasi-one-dimensional systems revealing a new phenomenon: collective oscillations of the grains with a characteristic frequency that is much lower than the frequency of energy injection. Theoretical work was then undertaken that is able to accurately predict the frequency of such an oscillation and Positron Emission Particle Tracking (PEPT) experiments were undertaken to provide the first experimental evidence of this new phenomenon. Finally, we briefly discuss ongoing work to create an open-source version of this ED via its integration in the existing open-source package MercuryDPM (http://MercuryDPM.org); which has many advanced features that are not found in other codes.

  14. Narrow Bandwidth Top-Emitting OLEDs Designed for Rhodamine 6G Excitation in Biological Sensing Applications

    Directory of Open Access Journals (Sweden)

    Matthias Jahnel

    2015-11-01

    Full Text Available Organic light emitting diodes (OLED are promising candidates offering in optical sensor applications to detect different gas compositions and excitable optical marker groups in chemical and biological processes. They enable attractive solutions for monitoring the gas phase composition of e.g., dissolved molecular oxygen (O2 species in bio reactors or excitation of fluorescent markers. In this work, we investigate different OLED devices for biomedical applications to excite the fluorescent dye rhodamine 6G (R6G. The OLED devices are built in top emission geometry comprising a distributed Bragg reflector (DBR acting as optical mirror. The OLED is optimized to provide a very narrow emission characteristic to excite the R6G at 530 nm wavelength and enabling the possibility to minimize the optical crosstalk between the OLED electroluminescence and the fluorescence of R6G. The DBR includes a thin film encapsulation and enables the narrowing of the spectral emission band depending on the number of DBR pairs. The comparison between optical simulation data and experimental results exhibits good agreement and proves process stability.

  15. Synthesis of iron oxide nanoparticles of narrow size distribution on polysaccharide templates

    Indian Academy of Sciences (India)

    M Nidhin; R Indumathy; K J Sreeram; Balachandran Unni Nair

    2008-02-01

    We report here the preparation of nanoparticles of iron oxide in the presence of polysaccharide templates. Interaction between iron (II) sulfate and template has been carried out in aqueous phase, followed by the selective and controlled removal of the template to achieve narrow distribution of particle size. Particles of iron oxide obtained have been characterized for their stability in solvent media, size, size distribution and crystallinity and found that when the negative value of the zeta potential increases, particle size decreases. A narrow particle size distribution with 100 = 275 nm was obtained with chitosan and starch templates. SEM measurements further confirm the particle size measurement. Diffuse reflectance UV–vis spectra values show that the template is completely removed from the final iron oxide particles and powder XRD measurements show that the peaks of the diffractogram are in agreement with the theoretical data of hematite. The salient observations of our study shows that there occurs a direct correlation between zeta potential, polydispersity index, bandgap energy and particle size. The crystallite size of the particles was found to be 30–35 nm. A large negative zeta potential was found to be advantageous for achieving lower particle sizes, owing to the particles remaining discrete without agglomeration.

  16. Handling difficult anastomosis. Tips and tricks in obese patients and narrow pelvis

    Directory of Open Access Journals (Sweden)

    Srinivas Samavedi

    2014-01-01

    Full Text Available Vesico-urethral anastomosis (VUA is a technically challenging step in robotic-assisted laparoscopic prostatectomy (RALP in obese individuals. We describe technical modifications to facilitate VUA encountered in obese individuals and in patients with a narrow pelvis. A Pubmed literature search was performed between 2000 and 2012 to review all articles related to RALP, obesity and VUA for evaluation of technique, complications and outcomes of VUA in obese individuals. In addition to the technical modifications described in the literature, we describe our own experience to encounter the technical challenges induced by obesity and narrow pelvis. In obese patients, technical modifications like use of air seal trocar technology, steep Trendlenburg positioning, bariatric trocars, alterations in trocar placement, barbed suture and use of modified posterior reconstruction facilitate VUA in robotic-assisted radical prostatectomy. The dexterity of the robot and the technical modifications help to perform the VUA in challenging patients with lesser difficulty. The experience of the surgeon is a critical factor in outcomes in these technically challenging patients, and obese individuals are best avoided during the initial phase of the learning curve.

  17. Highly tunable ultra-narrow-resonances with optical nano-antenna phased arrays in the infrared

    CERN Document Server

    Li, Shi-Qiang; Guo, Peijun; Buchholz, D Bruce; Qiu, Ziwei; Ketterson, John B; Ocola, Leonidas E; Sakoda, Kazuaki; Chang, Robert P H

    2014-01-01

    We report our recent development in pursuing high Quality-Factor (high-Q factor) plasmonic resonances, with vertically aligned two dimensional (2-D) periodic nanorod arrays. The 2-D vertically aligned nano-antenna array can have high-Q resonances varying arbitrarily from near infrared to terahertz regime, as the antenna resonances of the nanorod are highly tunable through material properties, the length of the nanorod, and the orthogonal polarization direction with respect to the lattice surface,. The high-Q in combination with the small optical mode volume gives a very high Purcell factor, which could potentially be applied to various enhanced nonlinear photonics or optoelectronic devices. The 'hot spots' around the nanorods can be easily harvested as no index-matching is necessary. The resonances maintain their high-Q factor with the change of the environmental refractive index, which is of great interest for molecular sensing.

  18. Nasal base narrowing: the combined alar base excision technique.

    Science.gov (United States)

    Foda, Hossam M T

    2007-01-01

    To evaluate the role of the combined alar base excision technique in narrowing the nasal base and correcting excessive alar flare. The study included 60 cases presenting with a wide nasal base and excessive alar flaring. The surgical procedure combined an external alar wedge resection with an internal vestibular floor excision. All cases were followed up for a mean of 32 (range, 12-144) months. Nasal tip modification and correction of any preexisting caudal septal deformities were always completed before the nasal base narrowing. The mean width of the external alar wedge excised was 7.2 (range, 4-11) mm, whereas the mean width of the sill excision was 3.1 (range, 2-7) mm. Completing the internal excision first resulted in a more conservative external resection, thus avoiding any blunting of the alar-facial crease. No cases of postoperative bleeding, infection, or keloid formation were encountered, and the external alar wedge excision healed with an inconspicuous scar that was well hidden in the depth of the alar-facial crease. Finally, the risk of notching of the alar rim, which can occur at the junction of the external and internal excisions, was significantly reduced by adopting a 2-layered closure of the vestibular floor (P = .01). The combined alar base excision resulted in effective narrowing of the nasal base with elimination of excessive alar flare. Commonly feared complications, such as blunting of the alar-facial crease or notching of the alar rim, were avoided by using simple modifications in the technique of excision and closure.

  19. Woodruff Narrows low head hydroelectric power plant feasibility determination

    Energy Technology Data Exchange (ETDEWEB)

    1979-03-01

    Woodruff Narrows Reservoir, owned by the State of Utah, was built in 1961 as an irrigation reservoir. The reservoir outlet works and spillway are in need of repair, and plans have been made to enlarge the reservoir from its present capacity of 28,000 acre-feet to 53,200 acre-feet when these repairs are made. The purpose of this study was to determine if it is feasible to add hydropower facilities when the reservoir is repaired and enlarged. A computer simulation model based on mean monthly values, utilizing 26 years of recorded streamflow into the reservoir, was used to determine the mean annual energy potential for the following configurations: (1) present dam, (2) the proposed enlarged dam, (3) a new dam at the lower site with a maximum head of 65 feet, and (4) a new dam at the lower site which would store water to the same elevation as the proposed enlarged dam. Results of the simulation study show that maximum power capacities are respectively 2.1, 3.0, 3.9, and 4.5 megawatts. The marketing potential for this electric power, cost estimates and financial analysis, and environmental, social, and regulatory aspects of the proposed hydropower facilities were evaluated. The results showed the addition of hydroelectric power development at the Woodruff Narrows site would have minimal social and environmental effects on the area, would result in little or no changes in the present patterns of water and land use, income, population, and employment and would not result in any significant changes of the social structure or characteristics of the area. However, hydroelectric power development at the Woodruff Narrows site is not economically feasible at the present time. (LCL)

  20. Theta Brain Rhythms Index Perceptual Narrowing in Infant Speech Perception

    Directory of Open Access Journals (Sweden)

    Alexis eBosseler

    2013-10-01

    Full Text Available The development of speech perception shows a dramatic transition between infancy and adulthood. Between 6 and 12 months, infants’ initial ability to discriminate all phonetic units across the worlds’ languages narrows—native discrimination increases while nonnative discrimination shows a steep decline. We used magnetoencephalography (MEG to examine whether brain oscillations in the theta band (4-8Hz, reflecting increases in attention and cognitive effort, would provide a neural measure of the perceptual narrowing phenomenon in speech. Using an oddball paradigm, we varied speech stimuli in two dimensions, stimulus frequency (frequent vs. infrequent and language (native vs. nonnative speech syllables and tested 6-month-old infants, 12-month-old infants, and adults. We hypothesized that 6-month-old infants would show increased relative theta power (RTP for frequent syllables, regardless of their status as native or nonnative syllables, reflecting young infants’ attention and cognitive effort in response to highly frequent stimuli (statistical learning. In adults, we hypothesized increased RTP for nonnative stimuli, regardless of their presentation frequency, reflecting increased cognitive effort for nonnative phonetic categories. The 12-month-old infants were expected to show a pattern in transition, but one more similar to adults than to 6-month-old infants. The MEG brain rhythm results supported these hypotheses. We suggest that perceptual narrowing in speech perception is governed by an implicit learning process. This learning process involves an implicit shift in attention from frequent events (infants to learned categories (adults. Theta brain oscillatory activity may provide an index of perceptual narrowing beyond speech, and would offer a test of whether the early speech learning process is governed by domain-general or domain-specific processes.

  1. Perceptual training narrows the temporal window of multisensory binding

    Science.gov (United States)

    Powers, Albert R.; Hillock, Andrea R.; Wallace, Mark T.

    2009-01-01

    The brain’s ability to bind incoming auditory and visual stimuli depends critically on the temporal structure of this information. Specifically, there exists a temporal window of audiovisual integration within which stimuli are highly likely to be bound together and perceived as part of the same environmental event. Several studies have described the temporal bounds of this window, but few have investigated its malleability. Here, the plasticity in the size of this temporal window was investigated using a perceptual learning paradigm in which participants were given feedback during a two-alternative forced-choice (2-AFC) audiovisual simultaneity judgment task. Training resulted in a marked (i.e., approximately 40%) narrowing in the size of the window. To rule out the possibility that this narrowing was the result of changes in cognitive biases, a second experiment employing a two-interval forced choice (2-IFC) paradigm was undertaken during which participants were instructed to identify a simultaneously-presented audiovisual pair presented within one of two intervals. The 2-IFC paradigm resulted in a narrowing that was similar in both degree and dynamics to that using the 2-AFC approach. Together, these results illustrate that different methods of multisensory perceptual training can result in substantial alterations in the circuits underlying the perception of audiovisual simultaneity. These findings suggest a high degree of flexibility in multisensory temporal processing and have important implications for interventional strategies that may be used to ameliorate clinical conditions (e.g., autism, dyslexia) in which multisensory temporal function may be impaired. PMID:19793985

  2. Visualized study on specific points on demand curves and flow patterns in a single-side heated narrow rectangular channel

    Energy Technology Data Exchange (ETDEWEB)

    Wang Junfeng [CNNC Key Laboratory on Reactor Thermo-Hydraulics Technology, Nuclear Power Institute of China, Chengdu, Sichuan (China); Huang Yanping, E-mail: hypgroup@163.com [CNNC Key Laboratory on Reactor Thermo-Hydraulics Technology, Nuclear Power Institute of China, Chengdu, Sichuan (China); Wang Yanlin [CNNC Key Laboratory on Reactor Thermo-Hydraulics Technology, Nuclear Power Institute of China, Chengdu, Sichuan (China)

    2011-10-15

    Highlights: > Specific points on the demand curve and flow patterns are visually studied. > Bubbly, churn, and annular flows were observed. > Onset of flow instability and bubbly-churn transition occurs at the same time. > The evolution of specific points and flow pattern transitions were examined. - Abstract: A simultaneous visualization and measurement study on some specific points on demand curves, such as onset of nucleate boiling (ONB), onset of significant void (OSV), onset of flow instability (OFI), and two-phase flow patterns in a single-side heated narrow rectangular channel, having a width of 40 mm and a gap of 3 mm, was carried out. New experimental approaches were adopted to identify OSV and OFI in a narrow rectangular channel. Under experimental conditions, the ONB could be predicted well by the Sato and Matsumura model. The OSV model of Bowring can reasonably predict the OSV if the single-side heated condition is considered. The OFI was close to the saturated boiling point and could be described accurately by Kennedy's correlation. The two-phase flow patterns observed in this experiment could be classified into bubbly, churn, and annular flow. Slug flow was never observed. The OFI always occurred when the bubbles at the channel exit began to coalesce, which corresponded to the beginning of the bubbly-churn transition in flow patterns. Finally, the evolution of specific points and flow pattern transitions were examined in a single-side heated narrow rectangular channel.

  3. Torsional instability in suspension bridges: The Tacoma Narrows Bridge case

    Science.gov (United States)

    Arioli, Gianni; Gazzola, Filippo

    2017-01-01

    All attempts of aeroelastic explanations for the torsional instability of suspension bridges have been somehow criticised and none of them is unanimously accepted by the scientific community. We suggest a new nonlinear model for a suspension bridge and we perform numerical experiments with the parameters corresponding to the collapsed Tacoma Narrows Bridge. We show that the thresholds of instability are in line with those observed the day of the collapse. Our analysis enables us to give a new explanation for the torsional instability, only based on the nonlinear behavior of the structure.

  4. Emerging role of narrow band imaging in duodenum

    Institute of Scientific and Technical Information of China (English)

    Amit; Kumar; Dutta; Ashok; Chacko

    2015-01-01

    Endoscopy using magnification narrow band imaging(m NBI) allows detailed assessment of mucosal surface and vascular pattern. This may help in better identification and prediction of the nature of the lesion. The role of this technology in duodenum is still evolving. Studies have shown that m NBI has high accuracy in predicting villous atrophy in the duodenum. Limited data suggests that this technique can provide additional information on duodenal polyps,nodules and ampullary tumour which can help guide their management. In this paper we describe the technique for duodenal assessment using NBI and review the existing literature evaluating its role in diagnosis of various duodenal pathologies.

  5. Internalization of Calcium Oxalate Calculi Developed in Narrow Cavities

    Directory of Open Access Journals (Sweden)

    Fèlix Grases

    2014-03-01

    Full Text Available We describe the case of a patient with calcium oxalate monohydrate and calcium oxalate dihydrate calculi occluded in cavities. All those calculi were located inside narrow cavities covered with a thin epithelium that permits their visualization. Urinary biochemical analysis showed high calciuria, not hypercalciuria, hypocitraturia, and a ratio [calcium]/[citrate] >0.33. The existence of cavities of very low urodynamic efficacy was decisive in the formation of such calculi. It is important to emphasize that we observed a thin epithelium covering such cavities, demonstrating that this epithelium may be formed after the development of the calculi through a re-epithelialization process.

  6. Tunable polarization plasma channel undulator for narrow bandwidth photon emission

    Science.gov (United States)

    Rykovanov, S. G.; Wang, J. W.; Kharin, V. Yu.; Lei, B.; Schroeder, C. B.; Geddes, C. G. R.; Esarey, E.; Leemans, W. P.

    2016-09-01

    The theory of a plasma undulator excited by a short intense laser pulse in a parabolic plasma channel is presented. The undulator fields are generated either by the laser pulse incident off-axis and/or under the angle with respect to the channel axis. Linear plasma theory is used to derive the wakefield structure. It is shown that the electrons injected into the plasma wakefields experience betatron motion and undulator oscillations. Optimal electron beam injection conditions are derived for minimizing the amplitude of the betatron motion, producing narrow-bandwidth undulator radiation. Polarization control is readily achieved by varying the laser pulse injection conditions.

  7. Narrow line diode laser stacks for DPAL pumping

    Science.gov (United States)

    Koenning, Tobias; Irwin, David; Stapleton, Dean; Pandey, Rajiv; Guiney, Tina; Patterson, Steve

    2014-02-01

    Diode pumped alkali metal vapor lasers (DPALs) offer the promise of scalability to very high average power levels while maintaining excellent beam quality, making them an attractive candidate for future defense applications. A variety of gain media are used and each requires a different pump wavelength: near 852nm for cesium, 780nm for rubidium, 766nm for potassium, and 670nm for lithium atoms. The biggest challenge in pumping these materials efficiently is the narrow gain media absorption band of approximately 0.01nm. Typical high power diode lasers achieve spectral widths around 3nm (FWHM) in the near infrared spectrum. With state of the art locking techniques, either internal to the cavity or externally mounted gratings, the spectral width can typically be reduced to 0.5nm to 1nm for kW-class, high power stacks. More narrow spectral width has been achieved at lower power levels. The diode's inherent wavelength drift over operating temperature and output power is largely, but not completely, eliminated. However, standard locking techniques cannot achieve the required accuracy on the location of the spectral output or the spectral width for efficient DPAL pumping. Actively cooled diode laser stacks with continuous wave output power of up to 100W per 10mm bar at 780nm optimized for rubidium pumping will be presented. Custom designed external volume holographic gratings (VHGs) in conjunction with optimized chip material are used to narrow and stabilize the optical spectrum. Temperature tuning on a per-bar-level is used to overlap up to fifteen individual bar spectra into one narrow peak. At the same time, this tuning capability can be used to adjust the pump wavelength to match the absorption band of the active medium. A spectral width of <0.1nm for the entire stack is achieved at <1kW optical output power. Tuning of the peak wavelength is demonstrated for up to 0.15nm. The technology can easily be adapted to other diode laser wavelengths to pump different materials.

  8. Masas de agujeros negros en Narrow Line Seyfert 1

    Science.gov (United States)

    Schmidt, E.; Ferreiro, D.; Oio, G.; Vega, L.; Donoso, L.

    We describe two of the ways to estimate black hole masses in AGN, and then we estimate the black hole masses of 13 Narrow Line Seyfert 1 galaxies with the two methods: virial masses, using the correlation found by Greene & Ho (2005, ApJ, 630, 122); and the correlation found by Tremaine et al. (2002, ApJ, 574, 740). For this work we analyzed the optical spectroscopy data we obtained from CASLEO (San Juan). We compare the results obtained through both methods. FULL TEXT IN SPANISH

  9. Narrow linewidth Brillouin laser based on chalcogenide photonic chip

    CERN Document Server

    Kabakova, Irina V; Choi, Duk-Yong; Debbarma, Sukhanta; Luther-Davies, Barry; Madden, Stephen J; Eggleton, Benjamin J

    2013-01-01

    We present the first demonstration of a narrow linewidth, waveguide-based Brillouin laser which is enabled by large Brillouin gain of a chalcogenide chip. The waveguides are equipped with vertical tapers for low loss coupling. Due to optical feedback for the Stokes wave, the lasing threshold is reduced to 360 mW, which is 5 times lower than the calculated single-pass Brillouin threshold for the same waveguide. The slope efficiency of the laser is found to be 30% and the linewidth of 100 kHz is measured using a self-heterodyne method.

  10. Narrow beam dosimetry for high-energy hadrons and electrons

    CERN Document Server

    Pelliccioni, M; Ulrici, Luisa

    2001-01-01

    Organ doses and effective dose were calculated with the latest version of the Monte Carlo transport code FLUKA in the case of an anthropomorphic mathematical model exposed to monoenergetic narrow beams of protons, pions and electrons in the energy range 10°— 400 GeV. The target organs considered were right eye, thyroid, thymus, lung and breast. Simple scaling laws to the calculated values are given. The present data and formula should prove useful for dosimetric estimations in case of accidental exposures to high-energy beams.

  11. Narrow beam dosimetry for high energy hadrons and electrons.

    Science.gov (United States)

    Pelliccioni, M; Silari, M; Ulrici, L

    2001-01-01

    Organ doses and effective dose were calculated with the latest version of the Monte Carlo transport code FLUKA in the case of an anthropomorphic mathematical model exposed to monoenergetic narrow beams of protons, pions and electrons in the energy range 10-400 GeV. The target organs considered were right eye, thyroid, thymus, lung and breast. Simple scaling laws to the calculated values are given. The present data and formulae should prove useful for dosimetric estimations in the case of accidental exposures to high energy beams.

  12. The Narrow-Field Telescope Science Case: A Proposal

    Science.gov (United States)

    Richer, M. G.

    2007-06-01

    Based upon the capabilities that are likely to be available from space and terrestrial observatories around 2015-2020 and the traditional interests of the Mexican astronomical community, I propose that the narrow-field telescope (NFT) be dedicated to high resolution spectroscopy covering wavelengths from the optical to the mid-infrared and adaptive optics imaging and spectroscopy (medium to high spectral resolution) in the near-infrared. These capabilities would permit studying the processes responsible for galaxy evolution after the epoch of mass assembly: the development of galactic structure, star formation, stellar structure and mass distributions, the kinematics and chemical composition of stars and the interstellar medium (ISM).

  13. Bayesian-Augmented Identification of Stars in a Narrow View

    Science.gov (United States)

    Clouse, Daniel; Padgett, Curtis

    2004-01-01

    An algorithm for the identification of stars from a charge-coupled-device (CCD) image of a star field has been extended for use with narrower field-of-view images. Previously, the algorithm had been shown to be effective at a field of view of 8 degrees. This work augments the earlier algorithm using Bayesian decision theory. The new algorithm is shown to be capable of effective star identification down to a field of view of 2 degrees. The algorithm was developed for use in estimating the attitude of a spacecraft and could be used on Earth to help in the identification of stars and other celestial objects for astronomical observations.

  14. Evidence for a Narrow Anti-Charmed Baryon State

    CERN Document Server

    Aktas, A; Anthonis, T; Asmone, A; Babaev, A; Backovic, S; Bähr, J; Baranov, P; Barrelet, E; Bartel, Wulfrin; Baumgartner, S; Becker, J; Beckingham, M; Behnke, O; Behrendt, O; Belousov, A; Berger, C; Berger, N; Berndt, T; Bizot, J C; Böhme, J; Boenig, M O; Boudry, V; Bracinik, J; Brisson, V; Broker, H B; Brown, D P; Bruncko, Dusan; Büsser, F W; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Caron, S; Cassol-Brunner, F; Cerny, K; Chekelian, V; Collard, Caroline; Contreras, J G; Coppens, Y R; Coughlan, J A; Cox, B E; Cozzika, G; Cvach, J; Dainton, J B; Dau, W D; Daum, K; Delcourt, B; Demirchyan, R; de Roeck, A; Desch, Klaus; De Wolf, E A; Diaconu, C; Dingfelder, J; Dodonov, V; Dubak, A; Duprel, C; Eckerlin, G; Efremenko, V; Egli, S; Eichler, R; Eisele, F; Ellerbrock, M; Elsen, E; Erdmann, M; Erdmann, W; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Ferencei, J; Fleischer, M; Fleischmann, P; Fleming, Y H; Flucke, G; Flügge, G; Fomenko, A; Foresti, I; Formánek, J; Franke, G; Frising, G; Gabathuler, Erwin; Gabathuler, K; Garutti, E; Garvey, J; Gayler, J; Gerhards, R; Gerlich, C; Ghazaryan, S; Glazov, A; Görlich, L; Gogitidze, N; Gorbounov, S; Grab, C; Grässler, Herbert; Greenshaw, T; Gregori, M; Grindhammer, G; Gwilliam, C; Haidt, D; Hajduk, L; Haller, J; Hansson, M; Heinzelmann, G; Henderson, R C W; Henschel, H; Henshaw, O; Heremans, R; Herrera-Corral, G; Herynek, I; Heuer, R D; Hildebrandt, M; Hiller, K H; Hoting, P; Hoffmann, D; Horisberger, R P; Hovhannisyan, A; Ibbotson, M; Ismail, M; Jacquet, M; Janauschek, L; Janssen, X; Jemanov, V; Jönsson, L B; Johnson, D P; Jung, H; Kant, D; Kapichine, M; Karlsson, M; Katzy, J; Keller, N; Kennedy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Klimkovich, T; Kluge, T; Knies, G; Knutsson, A; Koblitz, B; Korbel, V; Kostka, P; Koutouev, R; Kropivnitskaya, A; Kroseberg, J; Kuckens, J; Kuhr, T; Landon, M P J; Lange, W; Lastoviicka, T; Laycock, P; Lebedev, A; Leiner, B; Lemrani, R; Lendermann, V; Levonian, S; Lindfeld, L; Lipka, K; List, B; Lobodzinska, E; Loktionova, N A; López-Fernandez, R; Lubimov, V; Lüders, H; Lüke, D; Lux, T; Lytkin, L; Makankine, A; Malden, N; Malinovskii, E I; Mangano, S; Marage, P; Marks, J; Marshall, R; Martisikova, M; Martyn, H U; Maxfield, S J; Meer, D; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, J; Michine, S; Mikocki, S; Milcewicz, I; Milstead, D; Mohamed, A; Moreau, F; Morozov, A; Morozov, I; Morris, J V; Mozer, M U; Müller, K; Murn, P; Nagovizin, V; Naroska, Beate; Naumann, J; Naumann, T; Newman, P R; Niebuhr, C B; Nikiforov, A; Nikitin, D K; Nowak, G; Nozicka, M; Oganezov, R; Olivier, B; Olsson, J E; Ossoskov, G; Ozerov, D; Pascaud, C; Patel, G D; Peez, M; Pérez, E; Perieanu, A; Petrukhin, A; Pitzl, D; Placakyte, R; Pöschl, R; Portheault, B; Povh, B; Raicevic, N; Ratiani, Z; Reimer, P; Reisert, B; Rimmer, A; Risler, C; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A A; Rurikova, Z; Rusakov, S V; Rybicki, K; Sankey, D P C; Sauvan, E; Schatzel, S; Scheins, J; Schilling, F P; Schleper, P; Schmidt, S; Schmitt, S; Schneider, M; Schoeffel, L; Schöning, A; Schröder, V; Schultz-Coulon, H C; Schwanenberger, C; Sedlak, K; Sefkow, F; Shevyakov, I; Shtarkov, L N; Sirois, Y; Sloan, T; Smirnov, P; Soloviev, Yu; South, D; Spaskov, V; Specka, A; Spitzer, H; Stamen, R; Stella, B; Stiewe, J; Strauch, I; Straumann, U; Tchoulakov, V; Thompson, G; Thompson, P D; Tomasz, F; Traynor, D; Truöl, P; Tsipolitis, G; Tsurin, I; Turnau, J; Tzamariudaki, E; Uraev, A; Urban, M; Usik, A; Utkin, D; Valkár, S; Valkárová, A; Vallée, C; Van Mechelen, P; Van, N; Remortel; Vargas-Trevino, A; Vazdik, Ya A; Veelken, C; Vest, A; Vinokurova, S; Volchinski, V; Wacker, K; Wagner, J; Weber, G; Weber, R; Wegener, D; Werner, C; Werner, N; Wessels, M; Wessling, B; Winter, G G; Wissing, C; Woerling, E E; Wolf, R; Wünsch, E; Xella, S M; Yan, W; Yeganov, V; Zaicek, J; Zaleisak, J; Zhang, Z; Zhokin, A; Zohrabyan, H G; Zomer, F

    2004-01-01

    A narrow resonance in D*- p and D*+ pbar invariant mass combinations is observed in inelastic electron-proton collisions at centre-of-mass energies of 300 GeV and 320 GeV at HERA. The resonance has a mass of 3099 \\pm 3 (stat.) \\pm 5 (syst.) MeV and a measured Gaussian width of 12 \\pm 3 (stat.) MeV, compatible with the experimental resolution. The resonance is interpreted as an anti-charmed baryon with a minimal constituent quark composition of uuddcbar, together with the charge conjugate.

  15. China Hikes Refined Products Price to Narrow Gap

    Institute of Scientific and Technical Information of China (English)

    Dai Yanling

    2006-01-01

    @@ Rising international prices and China's increasing demand for oil, fueled by the country's fast economic growth, prompted it to hike the price of processed petroleum fuels several times in recent months. The price of gasoline, diesel and aviation kerosene jumped 500 yuan(62.4 U.S. dollars) per ton in late-May. The price increase,the second in the last two months, aims to narrow the gap between international oil prices and domestic prices, a spokesperson with the National Development and Reform Commission (NDRC), the industry watchdog, recently told news media.

  16. The Meteorology of Storms that Produce Narrow Bipolar Events

    Science.gov (United States)

    Lang, Timothy; McCaul, Bill; Fuchs, Brody; Cummer, Steve

    2013-01-01

    Narrow Bipolar Event's (NBE) are compact ( 10 kW in VHF), and impulsive (approx 10 micro s) electrical discharges in thunderstorms, also known as compact intracloud discharges (CIDs). Can be either positive or negative polarity and have distinctive broadband waveform signatures sometimes confused for +CGs in the past by NLDN and other networks. NBEs are related to lightning but are likely optically "dark". As revealed by VHF sensors (both satellite and ground): (1) The most powerful lightning-­-related VHF sources observed (2) Tend to occur at the beginning of intracloud discharges (3) Difficult to estimate altitude properly due to receiver saturation.

  17. The Dolichoarteriopathia of Common Carotid Artery Narrowing the Airway

    Directory of Open Access Journals (Sweden)

    Erkan Eski

    2013-01-01

    Full Text Available Tortuousity of the common carotid artery is rarely seen in otorinolaryngologic  practice. In this report, a case of tortuous common carotid artery narrowing the airway and indenting the epiglottis is presented. In endoscopic examination, pulsating bulge at the level of right lateral farengeal wall, pyriform sinus and larynx was found in a 73 year-old female. Computerized tomographic scan showed tortuous  right common carotid artery bulging the submucosal area of the oropharynx and pyriform sinus. Awareness of the tortuous common carotid artery before any  laryngologic surgical intervention is very important to prevent serious complications.

  18. Are Narrow Line Seyfert 1 Galaxies Viewed Pole-on?

    Science.gov (United States)

    2011-04-01

    0.2’’ respectively. Figure 1 displays the position of each slit over a Barbosa et al. (2009) GMOS IFU image of the [S III] flux (which originates...C. Winge, H. Schmitt: Gemini/ GMOS IFU gas velocity ’tomography’ of the narrow line region of nearby active galaxies, MNRAS, 396 (2009) 2. [2] D...1995) 81. 4 P o S ( N L S 1 ) 0 5 0 Are NLS1s Pole-on? Travis C. Fischer 5 Figure 1: NGC 4051 GMOS IFU image showing integrated [SIII] flux

  19. Theory of polaron bandwidth narrowing in organic molecular crystals

    Science.gov (United States)

    Hannewald, K.; Stojanović, V. M.; Schellekens, J. M.; Bobbert, P. A.; Kresse, G.; Hafner, J.

    2004-02-01

    We present a theoretical description of polaron bandwidth narrowing in organic molecular crystals. Based on a solution of a Holstein-Peierls model for tightly bound electrons interacting with phonons, an explicit expression for the temperature dependence of the electronic bandwidths is found. This formula generalizes the result of Holstein polaron theory by treating local and nonlocal electron-phonon coupling on equal footing. The usefulness of the method is demonstrated by model studies for oligo-acene crystals from which microscopic insight into the relevance of the different coupling mechanisms is obtained.

  20. Forced motion of an elastic filament through a narrow tube

    Science.gov (United States)

    Freund, L. B.

    2015-12-01

    A polymer filament consisting of many similar molecules linked in a one-dimensional array is very flexible. As a result, shapes with a relatively large curvature can be accommodated elastically. When loosely confined in a thermal environment, such a flexible strand may become tangled owing to its flexibility. When confined within a narrow "tube" over its full length, a flexible molecule may behave quite differently. Here, we consider the qualitative nature of deformation of an individual filament when confined within a tube. Commonly the tube is formed within the cluster by a large number of surrounding filaments of the same type.

  1. Narrow Bandwidth 850-nm Fiber Bragg Gratings in Few-Mode Polymer Optical Fibers

    DEFF Research Database (Denmark)

    Stefani, Alessio; Yuan, Wu; Markos, Christos;

    2011-01-01

    We report on the inscription and characterization of narrow bandwidth fiber Bragg gratings (FBGs) with 850-nm resonance wavelength in polymer optical fibers (POFs). We use two fibers: an in-house fabricated microstructured POF (mPOF) with relative hole size of 0.5 and a commercial step-index POF......, which supports six modes at 850 nm. The gratings have been written with the phase-mask technique and a 325-nm HeCd laser. The mPOF grating has a full-width at half-maximum (FWHM) bandwidth of 0.29 nm and the step-index POF has a bandwidth of 0.17 nm. For both fibers, the static tensile strain...

  2. Fast-tuning narrow-linewidth all polarization-maintaining fiber ring laser

    Science.gov (United States)

    Meng, Zhou; Hu, Zhengliang; Hu, Yongming; Xiong, Shuidong; Cao, Chunyan

    2007-04-01

    This paper describes the structure and operation of a stable, fast-tuning, narrow-linewidth, all polarization-maintaining fibre ring laser using erbium-doped fibre as a saturable absorber. The optimum pump power for single-mode operation in the laser is identified. Laser output power is ~4.0mW at 1536nm for a pump power of 80mW, the polarization extinction ratio is 25.0dB, the SNR is larger than 60dB, the relative intensity noise is below -118dB/Hz at frequencies above 90kHz. The phase noise achieves -107dB at 1kHz while the modulation frequency of lasing optical frequency is 12.5kHz.

  3. A Search for Low Surface Brightness Structure Around Compact Narrow Emission Line Galaxies

    CERN Document Server

    Barton, E J; Bershady, M A; Barton, Elizabeth J.; Zee, Liese van; Bershady, Matthew A.

    2006-01-01

    As the most extreme members of the rapidly evolving faint blue galaxy population at intermediate redshift, the compact narrow emission line galaxies (CNELGs) are intrinsically luminous (-22 -18). Conversely, 15 are not blue enough to fade to low-luminosity dwarfs (M_B > -15.2). The majority of the CNELGs are consistent with progenitors of intermediate-luminosity dwarfs and low-luminosity spiral galaxies with small disks. CNELGs are a heterogeneous progenitor population with significant fractions (up to 44%) capable of fading into today's faint dwarfs (M_B > -15.2), while 15 to 85% may only experience an apparently extremely compact CNELG phase at intermediate redshift but remain more luminous galaxies at the present epoch.

  4. Recent succession of the pedunculate oak and narrow-leaved ash forest in the unflooded part of Gornji Srem

    Directory of Open Access Journals (Sweden)

    Tomić Zagorka

    2002-01-01

    Full Text Available In the unflooded part of the river Sava, Bosut and Studva bottom lands in Gornji Srem (forest sections Moroviæ and Višnjiæevo, the following succession series are clearly differentiated on large areas: forests of narrow-leaved ash (Fraxinetum angustifoliae Jov. et Tom.1979. s.l on ((/(-(/(-gley ( forests of pedunculate oak and narrow-leaved ash (Fraxino-Quercetum roboris Jov. et Tom.1979. s.l on humogley, humosemigley and semigley ( forests of pedunculate oak, hornbeam and ash (Carpino-Fraxino-Quercetum roboris Jov. et Tom. 1979, s.l on semigley, brown forest soil and soil lessive Forest of pedunculate oak and narrow-leaved ash, which is an intermediary stage of the ecological succession series, is also differentiated into three ecological units (subassociations, which are the developmental phases of the association - primary, optimal and terminal – Forest of pedunculate oak and ash with hygrophilic accessories (Fraxino-Quercetum roboris hygrophyllum on moderately moist hydromorphic black soils (humogley, ecological (-gley is the primary phase, ecologically and syn-dynamically related to the terminal phase of the previous stage – forest of narrow-leaved ash with sedge (Fraxinetum angustifoliae caricetosum remotae on (/(-gley. The dominant edificator is narrow-leaved ash, while pedunculate oak is in the subdominant position Moister meadow black soils are characterised by intensive moisture, because already at the depth of 20/30-50 cm, the process of gleying occurs. Underground water stagnates at the depth of 80-120 cm – Typical forest of pedunculate oak and ash (Fraxino-Quercetum roboris typicum on the drier varieties of humosemigley is the optimal phase in the development of the association, with a slowed down dynamism. Both edificators are in their ecological and coenological optima, i.e. the conditions of their development are excellent In the drier hygromorphic black soils the level of underground water is about 40 cm lower than the

  5. Narrow multibeam satellite ground station antenna employing a linear array with a geosynchronous arc coverage of 60 deg. I - Theory

    Science.gov (United States)

    Amitay, N.; Gans, M. J.

    1982-11-01

    The feasibility of using an appropriately squinted linear scan in narrow multibeam satellite ground station antennas employing phased arrays is demonstrated. This linear scan has the potential of reducing the complexity of a narrow-beam planar array to that of a linear array. Calculations for such antennas placed at cities throughout the U.S. show that the peak beam pointing error in covering the 70 deg W to 130 deg W geosynchronous equatorial arc (GEA) is under 5/1000th of a degree. Communication at a 300 MBd rate in the 12/14 GHz band can be made feasible, for a grating lobe-free scan and 0.5 deg beamwidth antenna, by using a relatively simple time equalization.

  6. Usefulness of Chromoendoscopy and Narrow Band Imaging in Barrett's Esophagus

    Directory of Open Access Journals (Sweden)

    Engy Yousry El Sayed

    2014-12-01

    Full Text Available Barrett's esophagus (BE is the most important risk factor for esophageal adenocarcinoma. High resolution magnification endoscopy with Narrow band imaging (NBI facilitates mucosal surface evaluation and may improve the endoscopic diagnosis of Barrett’s esophagus. The aim of this work was to study the diagnostic value of chromo endoscopy versus NBI in detection of Barrett’s esophagus. Patients and methods: Forty patients their conventional white light endoscopy revealed the diagnosis of GERD and showed findings suggestive of Barrett’s esophagus, they were divided into 20 patients underwent chromo endoscopy and 20 patients underwent Narrow band imaging (NBI, The endoscopic results of both groups were compared with the final histo pathological diagnosis. Results: NBI showed higher accuracy than chromo endoscopy 75 % which vs. 70 % P< 0.05 in detection of BE. NBI had an accuracy of 70 and 75 % in type A pattern (round pits with regular microvasculature to predict columnar mucosa without intestinal metaplasia and type B pattern (villous pits with regular microvasculature to predict specialized intestinal metaplasia respectively. Conclusion: NBI is not only helpful in detecting metaplasia but also in differentiating cardiac from intestinal metaplasia, as it allows clear visualization of micro structural and micro vascular patterns.

  7. Superscattering-enhanced narrow band forward scattering antenna

    Science.gov (United States)

    Hu, De-Jiao; Zhang, Zhi-You; Du, Jing-Lei

    2015-10-01

    We present a narrow band forward scattering optical antenna which is based on the excitation of distinctive whispering gallery modes (WGMs). The antenna is composed of three coaxial cylinder layers: a dielectric layer is sandwiched between a metallic core and cladding. Owing to the destructive interference between the scattering of the outer metallic cladding and the WGM in the backward direction, the power flow in the forward direction is increased. Simulation and analysis show that in proper geometry conditions, the cavity can be tuned into a superscattering state. At this state, both the zeroth and the first order of WGM are excited and contribute to the total scattering. It is shown that the power ratio (power towards backward divided by power towards forward) can be enhanced to about 27 times larger than that for a non-resonant position by the superscattering. Owing to the confinement of the cladding to WGMs, the wavelength range of effective forward scattering is considerably narrow (about 15 nm). Project supported by the National Natural Science Foundation of China (Grant No. 61377054), the Collaborative Innovation Foundation of Sichuan University, China (Grant No. XTCX 2013002), and the International Cooperation and Exchange of Science and Technology Project in Sichuan Province, China (Grant No. 2013HH0010).

  8. Superscattering-enhanced narrow band forward scattering antenna

    Institute of Scientific and Technical Information of China (English)

    胡德骄; 张志友; 杜惊雷

    2015-01-01

    We present a narrow band forward scattering optical antenna which is based on the excitation of distinctive whispering gallery modes (WGMs). The antenna is composed of three coaxial cylinder layers:a dielectric layer is sandwiched between a metallic core and cladding. Owing to the destructive interference between the scattering of the outer metallic cladding and the WGM in the backward direction, the power fl ow in the forward direction is increased. Simulation and analysis show that in proper geometry conditions, the cavity can be tuned into a superscattering state. At this state, both the zeroth and the first order of WGM are excited and contribute to the total scattering. It is shown that the power ratio (power towards backward divided by power towards forward ) can be enhanced to about 27 times larger than that for a non-resonant position by the superscattering. Owing to the confinement of the cladding to WGMs, the wavelength range of effective forward scattering is considerably narrow (about 15 nm).

  9. Critical Heat Flux In Inclined Rectangular Narrow Long Channel

    Energy Technology Data Exchange (ETDEWEB)

    J. L. Rempe; S. W. Noh; Y. H. Kim; K. Y. Suh; F.B.Cheung; S. B. Kim

    2005-05-01

    In the TMI-2 accident, the lower part of the reactor pressure vessel had been overheated and then rather rapidly cooled down, as was later identified in a vessel investigation project. This accounted for the possibility of gap cooling feasibility. For this reason, several investigations were performed to determine the critical heat flux (CHF) from the standpoint of invessel retention. The experiments are conducted to investigate the general boiling phenomena, and the triggering mechanism for the CHF in a narrow gap using a 5 x 105 mm2 crevice type heater assembly and de-mineralized water. The test parameters include the gap size of 5 mm, and the surface orientation angles from the downward facing position (180o) to the vertical position (90o). The orientation angle affects the bubble layer and escape from the narrow gap. The CHF is less than that in a shorter channel, compared with the previous experiments having a heated length of 35 mmin the copper test section.

  10. Narrow-band imaging optical chromocolonoscopy: Advantages and limitations

    Institute of Scientific and Technical Information of China (English)

    Fabian Emura; Yutaka Saito; Hiroaki Ikematsu

    2008-01-01

    Narrow-band imaging(NBI)is an innovative optical technology that modifies the center wavelength and bandwidth of an endoscope's light into narrow-band illumination of 415±30 nm.NBI markedly improves capillary pattern contrast and is an in vivo method for visualizing microvessel morphological changes in superficial neoplastic lesions.The scientific basis for NBI is that short wavelength light falls within the hemoglobin absorption band,thereby facilitating clearer visualization of vascular structures.Severalstudies have reported advantages and limitations of NBI colonoscopy in the colorectum.One difficulty in evaluating results,however,has been non-standardization of NBI systems(Sequential and non-sequential).Utilization of NBI technology has been increasing worldwide,but accurate pit pattern analysis and sufficient skill in magnifying colonoscopy are basic fundamentals required for proficiency in NBI diagnosis of colorectal lesions.Modern optical technology without proper image interpretation wastes resources,confuses untrained endoscopists and delays inter institutional validation studies.Training in the principles of"optical image-enhanced endoscopy"is needed to close the gap between technological advancements and their clinical usefulness.Currently available evidence indicates that NBI constitutes an effective and reliable alternative to chromocolonoscopy for in vivo visualization of vascular structures,but further study assessing reproducibility and effectiveness in the colorectum is ongoing at various medical centers.

  11. Defect-induced bandgap narrowing in low-k dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Guo, X.; Zheng, H.; Shohet, J. L. [Plasma Processing & Technology Laboratory and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); King, S. W. [Logic Technology Development, Intel Corporation, Hillsboro, Oregon 97124 (United States); Afanas' ev, V. V. [Department of Physics, University of Leuven, B-3001 Leuven (Belgium); Baklanov, M. R.; Marneffe, J.-F. de [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Nishi, Y. [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2015-08-24

    In this work, core-level X-ray photoelectron spectroscopy was utilized to determine the surface bandgap for various porous and non-porous low-k a-SiCOH dielectrics before and after ion sputtering. By examining the onset of inelastic energy loss in O 1s core-level spectra, the gap narrowing was universally found in Ar{sup +} ion sputtered low-k dielectrics. The reduction of the bandgap ranges from 1.3 to 2.2 eV depending on the film composition. We show that the bandgap narrowing in these low-k dielectrics is caused by development of the valence-band tail as evidenced by the presence of additional electronic states above the valence-band maximum. Electron-spin-resonance measurements were made on a-SiCOH films to gain atomic insight into the nature of the sputtering-induced defects and reveal formation of carbon-related defects as the most probable origin of the gap states.

  12. Narrow band imaging of tumors using gold nanoshells

    Science.gov (United States)

    Puvanakrishnan, Priyaveena; Park, Jaesook; Diagaradjane, Parameshwaran; Schwartz, Jon A.; Coleman, Chris L.; Gill-Sharp, Kelly L.; Sang, Kristina L.; Payne, J. Donald; Krishnan, Sunil; Tunnell, James W.

    2009-02-01

    Gold nanoshells (GNS) are a new class of nanoparticles that can be optically tuned to scatter or absorb light from the near-ultraviolet to near-infrared (NIR) region by varying the core (dielectric silica) /shell (gold) ratio. In addition to spectral tunability, GNS are inert and bioconjugatable making them potential labels for in vivo imaging and therapy of tumors. We report the use of GNS as exogenous contrast agents for enhanced visualization of tumors using narrow band imaging (NBI). NBI takes advantage of the strong NIR absorption of GNS to distinguish between blood and nanoshells in the tumor by imaging in narrow wavelength bands in the visible and NIR, respectively. Using tissue-simulating phantoms, we determined the optimum wavelengths to enhance contrast between blood and GNS. We then used the optimum wavelengths for ex-vivo imaging of tumors extracted from human colon cancer xenograft bearing mice injected with GNS. Systemically delivered GNS accumulated passively in tumor xenografts by the enhanced permeability and retention (EPR) effect. Ex-vivo NBI of tumor xenografts demonstrated tumor specific heterogeneous distribution of GNS with a clear distinction from the tumor vasculature. The results of this study demonstrate the feasibility of using GNS as contrast agents to visualize tumors using NBI.

  13. Sub-kilohertz laser linewidth narrowing using polarization spectroscopy.

    Science.gov (United States)

    Torrance, Joshua S; Sparkes, Ben M; Turner, Lincoln D; Scholten, Robert E

    2016-05-30

    We identify several beneficial characteristics of polarization spectroscopy as an absolute atomic reference for frequency stabilization of lasers, and demonstrate sub-kilohertz laser spectral linewidth narrowing using polarization spectroscopy with high-bandwidth feedback. Polarization spectroscopy provides a highly dispersive velocity-selective absolute atomic reference based on frequency-dependent birefringence in an optically pumped atomic gas. The pumping process leads to dominance of the primary closed transition, suppressing closely-spaced subsidiary resonances which reduce the effective capture range for conventional atomic references. The locking signal is based on subtraction of two orthogonal polarization signals, reducing the effect of laser intensity noise to the shot noise limit. We measure noise-limited servo bandwidth comparable to that of a high-finesse optical cavity without the frequency limit or complexity imposed by optical modulation normally associated with high bandwidth laser frequency stabilization. We demonstrate narrowing to 600±100 Hz laser linewidth using the beatnote between two similarly locked external cavity diode lasers.

  14. Tidal disruption of satellites and formation of narrow rings

    CERN Document Server

    Leinhardt, Zoe M; Latter, Henrik N; Kokubo, Eiichiro

    2012-01-01

    In this paper we investigate the formation of narrow planetary rings such as those found around Uranus and Saturn through the tidal disruption of a weak, gravitationally bound satellite that migrates within its Roche limit. Using $N$-body simulations, we study the behaviour of rubble piles placed on circular orbits at different distances from a central planet. We consider both homogeneous satellites and differentiated bodies containing a denser core. We show that the Roche limit for a rubble pile is closer to the planet than for a fluid body of the same mean density. The Roche limit for a differentiated body is also closer to the planet than for a homogeneous satellite of the same mean density. Within its Roche limit, a homogeneous satellite totally disrupts and forms a narrow ring. The initial stages of the disruption are similar to the evolution of a viscous fluid ellipsoid, which can be computed semi-analytically. On the other hand, when a differentiated satellite is just within the Roche limit only the ma...

  15. Formation of wind-driven ice bridges in narrow straits

    Science.gov (United States)

    Rallabandi, Bhargav; Zheng, Zhong; Winton, Michael; Stone, Howard A.

    2016-11-01

    An ice bridge is a static arch made of tightly packed ice that can be formed when sea ice flows through a narrow strait between landmasses. The formation of a stable ice arch prevents the further flow of sea ice into warmer oceans, and therefore plays an important role in the regulation of the local climate and ecology and to an extent, the mass balance of Arctic ice. While ice bridges are a seasonal phenomenon in many parts of the Canadian Archipelago, the process of their formation and breakup is poorly understood. Using thin-layer theory along with dynamic sea ice models widely used in climate modeling, we develop a reduced-order description of wind-driven ice bridge formation in long, narrow straits. Our theory predicts a critical static condition for arrested flow that involves the ice properties (thickness and compactness), the geometry of the channel, and the magnitude of the wind stress. Further, we show that in a channel of varying shape and under a constant wind stress, a spatially uniform ice field evolves towards a steady state with discontinuities in its properties, consistent with observed mechanisms of ice bridge formation. The reduced-order model thus provides a predictive tool for the flow and stoppage of sea ice in straits.

  16. Explore the Energy-saving Effect of Decomposition Kiln System with Four-stage, Five-stage and Six-stage Preheater%四级、五级和六级预热预分解窑系统节能效果的探讨

    Institute of Scientific and Technical Information of China (English)

    李红建; 王国鸿; 周刘成; 李昌勇

    2013-01-01

    通过四级、五级和六级预热预分解窑系统节约煤电的比较,阐明了带余热发电的五级预热预分解窑系统的能源利用率高于带余热发电的四级预热预分解窑系统,而六级预热器系统比五级、四级预热器系统节能效果更好.采用六级预热器系统可以适当降低预热器出口废气温度,实现废气热焓的充分回收,从而有效地实现烧成系统的节能减排.%By contrasting energy-saving of decomposition kiln system with four-stage, five-stage and six-stage preheater, it clarified that energy efficiency of system with five-stage preheater and waste heat power generation was higher than system with four-stage preheater. The energy-saving effect of six-stage preheater is better than five-stage and four-stage preheater. Six-stage preheater system was appropriate to reduce the outlet exhaust gas temperature of the preheater, while the exhaust gas enthalpy could be fully recycled,which easily achieved the purpose of the energy-saving and emissions reduction of the firing system.

  17. The encapsulation of an amphiphile into polystyrene microspheres of narrow size distribution

    Directory of Open Access Journals (Sweden)

    Pellach Michal

    2011-12-01

    Full Text Available Abstract Encapsulation of compounds into nano- or microsized organic particles of narrow size distribution is of increasing importance in fields of advanced imaging and diagnostic techniques and drug delivery systems. The main technology currently used for encapsulation of molecules within uniform template particles while retaining their size distribution is based on particle swelling methodology, involving penetration of emulsion droplets into the particles. The swelling method, however, is efficient for encapsulation only of hydrophobic compounds within hydrophobic template particles. In order to be encapsulated, the molecules must favor the hydrophobic phase of an organic/aqueous biphasic system, which is not easily achieved for molecules of amphiphilic character. The following work overcomes this difficulty by presenting a new method for encapsulation of amphiphilic molecules within uniform hydrophobic particles. We use hydrogen bonding of acid and base, combined with a pseudo salting out effect, for the entrapment of the amphiphile in the organic phase of a biphasic system. Following the entrapment in the organic phase, we demonstrated, using fluorescein and (antibiotic tetracycline as model molecules, that the swelling method usually used only for hydrophobes can be expanded and applied to amphiphilic molecules.

  18. Brilliant GeV electron beam with narrow energy spread generated by a laser plasma accelerator

    Directory of Open Access Journals (Sweden)

    Ronghao Hu

    2016-09-01

    Full Text Available The production of GeV electron beam with narrow energy spread and high brightness is investigated using particle-in-cell simulations. A controlled electron injection scheme and a method for phase-space manipulation in a laser plasma accelerator are found to be essential. The injection is triggered by the evolution of two copropagating laser pulses near a sharp vacuum-plasma transition. The collection volume is well confined and the injected bunch is isolated in phase space. By tuning the parameters of the laser pulses, the parameters of the injected electron bunch, such as the bunch length, energy spread, emittance and charge, can be adjusted. Manipulating the phase-space rotation with the rephasing technique, the injected electron bunch can be accelerated to GeV level while keeping relative energy spread below 0.5% and transverse emittance below 1.0  μm. The results present a very promising way to drive coherent x-ray sources.

  19. The encapsulation of an amphiphile into polystyrene microspheres of narrow size distribution.

    Science.gov (United States)

    Pellach, Michal; Margel, Shlomo

    2011-12-06

    Encapsulation of compounds into nano- or microsized organic particles of narrow size distribution is of increasing importance in fields of advanced imaging and diagnostic techniques and drug delivery systems. The main technology currently used for encapsulation of molecules within uniform template particles while retaining their size distribution is based on particle swelling methodology, involving penetration of emulsion droplets into the particles. The swelling method, however, is efficient for encapsulation only of hydrophobic compounds within hydrophobic template particles. In order to be encapsulated, the molecules must favor the hydrophobic phase of an organic/aqueous biphasic system, which is not easily achieved for molecules of amphiphilic character.The following work overcomes this difficulty by presenting a new method for encapsulation of amphiphilic molecules within uniform hydrophobic particles. We use hydrogen bonding of acid and base, combined with a pseudo salting out effect, for the entrapment of the amphiphile in the organic phase of a biphasic system. Following the entrapment in the organic phase, we demonstrated, using fluorescein and (antibiotic) tetracycline as model molecules, that the swelling method usually used only for hydrophobes can be expanded and applied to amphiphilic molecules.

  20. 76 FR 60733 - Drawbridge Operation Regulations; Narrow Bay, Smith Point, NY

    Science.gov (United States)

    2011-09-30

    ... SECURITY Coast Guard 33 CFR Part 117 Drawbridge Operation Regulations; Narrow Bay, Smith Point, NY AGENCY... the Smith Point Bridge, 6.1, across Narrow Bay, between Smith Point and Fire Island, New York. The.... SUPPLEMENTARY INFORMATION: The Smith Point Bridge, across Narrow Bay, mile 6.1, between Smith Point and...

  1. Grassy Narrows Reserve: Mercury Pollution, Social Disruption, and Natural Resources: A Question of Autonomy.

    Science.gov (United States)

    Vecsey, Christopher

    1987-01-01

    Presents chronological socio-economic account of Grassy Narrows Reserve, focusing on the 1962-1970 mercury pollution that poisoned the reserve's river system and on resulting negotiations between the Ojibway people of Grassy Narrows, the government, and the polluting company. Examines the question of Grassy Narrows people gaining autonomy over the…

  2. Produced Fluid Treatment at SAGD Steam Circulation Preheating Stage in Fengcheng Oilfield%风城油田SAGD循环预热采出液处理技术

    Institute of Scientific and Technical Information of China (English)

    霍进; 陈贤; 桑林翔; 陈弘毅; 李学军

    2016-01-01

    Conventional oil demulsifier is ineffective for produced fluid at SAGD steam cir-culation preheating stage in Fengcheng oilfield. The produced fluid flowing into oil process plant leads to water- cut increasing in crude oil and sewage treatment difficulty. With the wide application of SAGD technique in super heavy oil exploitation, produced fluid treat-ment becomes a critical problem to be resolved. The stabilization mechanism of produced fluid was investigated by physical properties analysis,micrographic determination and zeta po-tential measurement, and the colloidal dispersion character of produced fluid was recognized. Based on high efficient treatment agents and process optimization, produced fluid oil- water separation, floating oil dehydration and sewage purification were realized. The process tech-nique that vapor- liquid separation, spraying cooling, oil- water separation, and floating oil recovery for produced fluid treatment was formed, which is an important technical guar-antee for SAGD development and a good reference for similar reservoir development.%在风城油田SAGD循环预热采出液处理中使用常规破乳药剂无法实现油水分离,采出液进入稠油处理站后,易造成净化原油含水升高、脱出污水净化困难.随着超稠油SAGD开发规模的不断扩大,亟待解决循环预热采出液的处理难题.通过物性分析、显微照相和Zeta电位测定等手段研究了循环预热采出液的稳定机理以及循环预热采出液的胶体分散特性,并研制出复合净水药剂进行破胶,结合工艺优化实现了循环预热采出液的油水分离、浮油脱水和污水净化,形成了"汽液分离+喷淋降温+油水分离+浮油回收"的循环预热采出液处理工艺技术.该技术为SAGD规模开发提供了技术保障,为同类油藏的开发提供了借鉴.

  3. Influence of the pre-ionization background and simulation of the optical emission of a streamer discharge in preheated air at atmospheric pressure between two point electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Bourdon, A; Bonaventura, Z [Ecole Centrale Paris, EM2C Laboratory, UPR CNRS 288, Grande voie des vignes, 92295 Chatenay-Malabry Cedex (France); Celestin, S, E-mail: anne.bourdon@em2c.ecp.f [Communications and Space Sciences Laboratory, Department of Electrical Engineering, Pennsylvania State University, University Park, PA 16802 (United States)

    2010-06-15

    This paper presents simulations of positive and negative streamers propagating between two point electrodes in preheated air at atmospheric pressure. As many discharges have occurred before the simulated one, seed charges are taken into account in the interelectrode gap. First, for a pre-ionization background of 10{sup 9} cm{sup -3}, we have studied the influence of the data set used for transport parameters and reaction rates for air on the simulation results. We have compared results obtained in 1997 using input parameters from Morrow and Lowke and from Kulikovsky. Deviations as large as 20% of streamer characteristics (i.e. electric field in the streamer head and body, streamer velocity, streamer radius, streamer electron density) have been observed for this point-to-point configuration. Second, we have studied the influence of the pulsed voltage frequency on the discharge structure. For the studied discharge regime, a change in the applied voltage frequency corresponds to a change in the pre-ionization background. In this work, we have considered a wide range of pre-ionization values from 10{sup 4} and up to 10{sup 9} cm{sup -3}. We have noted that the value of the pre-ionization background has a small influence on the electron density, electric field and location of the negative streamer head. Conversely, it has a significant influence on the positive streamer characteristics. Finally, we have compared instantaneous and time-averaged optical emissions of the three band systems of N{sub 2} and N{sub 2}{sup +} (1PN{sub 2}, 2PN{sub 2} and 1NN{sub 2}{sup +}) during the discharge propagation. We have shown that the emission of the 2PN{sub 2} is the strongest of the three bands, in agreement with experimental observations. It is interesting to note that even with a short time averaging of a few nanoseconds, which corresponds to currently used instruments, the structure of the time-averaged emission of the 2PN{sub 2} is different from the instantaneous one and shows

  4. CHEERS Results from NGC 3393, II: Investigating the Extended Narrow Line Region using Deep Chandra Observations and Hubble Narrow Line Imaging

    CERN Document Server

    Maksym, W Peter; Elvis, Martin; Karovska, Margarita; Paggi, Alessandro; Raymond, John; Wang, Junfeng; Storchi-Bergmann, Thaisa

    2016-01-01

    The CHandra Extended Emission Line Region Survey (CHEERS) is an X-ray study of nearby active galactic nuclei (AGN) designed to take full advantage of Chandra's unique angular resolution by spatially resolving feedback signatures and effects. In the second paper of a series on CHEERS target NGC 3393, we examine deep high-resolution Chandra images and compare them with Hubble narrow line images of [O III], [S II] and H$\\alpha$, as well as previously-unpublished mid-ultraviolet (MUV) images. We find evidence for a complex multi-phase structure in the circumnuclear ISM, with no single simple correlation between X-rays and high-ionization ([O III]/H$\\alpha$-dominated) and low-ionization ([S II]-dominated) features. We also find X-ray structures ~50-pc in extent, H$\\alpha$ evidence for gas compression, and extended MUV emission associated with the S-shaped arms that envelope the radio jets. In conjunction with existing STIS kinematics, these findings support a role for shock contributions to the feedback, driven by...

  5. Crystallization of Poly(3-hexylthiophene Nanofiber in a Narrow Groove

    Directory of Open Access Journals (Sweden)

    Satoshi Kushi

    2016-06-01

    Full Text Available Whisker-type poly(3-hexylthiophene-2,5-diyl (P3HT nanofibers were aligned by restricting their growth direction using an approximately 100–1000 nm wide narrow groove fabricated by thermal nanoimprinting. In grooves made of an amorphous fluoropolymer (CYTOP™ with widths of less than 1500 nm, the nanofibers oriented uniaxially perpendicular to the groove and their length was limited to the width of the groove. This result indicates that the nucleation of nanofibers tends to be selectively promoted near the interface of CYTOP™ with fluoro-groups, and nanofiber growth perpendicular to the wall is promoted because P3HT molecules are supplied more frequently from the center of the groove. Furthermore, the orientation induced anisotropic conductivity, and the conductivity parallel to the oriented nanofibers was more than an order of magnitude higher than that perpendicular to the oriented nanofibers.

  6. High unexpected genetic diversity of a narrow endemic terrestrial mollusc.

    Science.gov (United States)

    Madeira, Pedro M; Chefaoui, Rosa M; Cunha, Regina L; Moreira, Francisco; Dias, Susana; Calado, Gonçalo; Castilho, Rita

    2017-01-01

    The Iberian Peninsula has an extensive record of species displaying strong genetic structure as a result of their survival in isolated pockets throughout the Pleistocene ice ages. We used mitochondrial and nuclear sequence data to analyze phylogeographic patterns in endemic land snails from a valley of central Portugal (Vale da Couda), putatively assigned to Candidula coudensis, that show an exceptionally narrow distributional range. The genetic survey presented here shows the existence of five main mitochondrial lineages in Vale da Couda that do not cluster together suggesting independent evolutionary histories. Our results also indicate a departure from the expectation that species with restricted distributions have low genetic variability. The putative past and contemporary models of geographic distribution of Vale da Couda lineages are compatible with a scenario of species co-existence in more southern locations during the last glacial maximum (LGM) followed by a post-LGM northern dispersal tracking the species optimal thermal, humidity and soil physical conditions.

  7. Flight Calibration of the LROC Narrow Angle Camera

    Science.gov (United States)

    Humm, D. C.; Tschimmel, M.; Brylow, S. M.; Mahanti, P.; Tran, T. N.; Braden, S. E.; Wiseman, S.; Danton, J.; Eliason, E. M.; Robinson, M. S.

    2016-04-01

    Characterization and calibration are vital for instrument commanding and image interpretation in remote sensing. The Lunar Reconnaissance Orbiter Camera Narrow Angle Camera (LROC NAC) takes 500 Mpixel greyscale images of lunar scenes at 0.5 meters/pixel. It uses two nominally identical line scan cameras for a larger crosstrack field of view. Stray light, spatial crosstalk, and nonlinearity were characterized using flight images of the Earth and the lunar limb. These are important for imaging shadowed craters, studying ˜1 meter size objects, and photometry respectively. Background, nonlinearity, and flatfield corrections have been implemented in the calibration pipeline. An eight-column pattern in the background is corrected. The detector is linear for DN = 600--2000 but a signal-dependent additive correction is required and applied for DNground-based images taken with the Robotic Lunar Observatory (ROLO) at much lower spatial resolution but with the same photometric angles.

  8. Neutral and positively charged excitons in narrow quantum ring

    Energy Technology Data Exchange (ETDEWEB)

    Porras Monroy, L. C.; Rodríguez-Prada, F. A.; Mikhailov, I. D. [Escuela de Física, Universidad Industrial de Santander, A. A. 678, Bucaramanga (Colombia)

    2014-05-15

    We study theoretically quantized states of a neutral and a positively charged exciton (trion X{sup +}) confined in a heterostructure with the ring-like geometry. In order to assess the experimentally relevant domain of parameters, we adopt a simple model of a narrow ring when 3D wave equations for the neutral and positively charged excitons can be separated. By using the Fourier series method, we have calculated the energy spectra of excitons complexes in a quantum ring as a function of the electron-to-hole mass ratio, the ring radius, and the magnetic field strength. The quantum-size effect and the size-dependent magnetic oscillations of energy levels of excitons' complexes spectra have been revealed.

  9. Narrow sidebranch arrays for low frequency duct noise control.

    Science.gov (United States)

    Tang, S K

    2012-11-01

    The present study investigates the sound transmission loss across a section of an infinitely long duct where one or more narrow sidebranch tubes are installed flushed with the duct wall. The finite-element method is used to compute the wave propagation characteristics, and a simplified theoretical analysis is carried out at the same time to explain the wave mechanism at frequencies of high sound reduction. Results show that the high sound transmission loss at a particular frequency is due to the concerted actions of three consecutive sidebranch tubes with the most upstream one in the resonant state. The expansion chamber effect of the setup also plays a role in enhancing sound attenuation at non-resonance frequencies. Broadband performance of the device can be greatly enhanced by appropriate arrangements of tube lengths and/or by coupling arrays on the two sides of the duct.

  10. Narrow Field of View Zenith Radiometer (NFOV) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, C; Marshak, A; Hodges, G; Barnard, JC; Schmelzer, J

    2008-11-01

    The two-channel narrow field-of-view radiometer (NFOV2) is a ground-based radiometer that looks straight up and measures radiance directly above the instrument at wavelengths of 673 and 870 nm. The field-of-view of the instrument is 1.2 degrees, and the sampling time resolution is one second. Measurements of the NFOV2 have been used to retrieve optical properties for overhead clouds that range from patchy to overcast. With a one-second sampling rate of the NFOV2, faster than almost any other ARM Climate Research Facility (ACRF) instrument, we are able, for the first time, to capture changes in cloud optical properties at the natural time scale of cloud evolution.

  11. The Chemical Vapour Deposition of Tantalum - in long narrow channels

    DEFF Research Database (Denmark)

    Mugabi, James Atwoki

    use as a construction material for process equipment, with the cheaper alternative being the construction of equipment from steel and then protecting it with a thin but efficacious layer of tantalum. Chemical Vapour Deposition (CVD) is chosen as the most effective process to apply thin corrosion...... protective layers of tantalum because of the process’ ability to coat complex geometries and its relative ease to control. This work focuses on studying the CVD of tantalum in long narrow channels with the view that the knowledge gained during the project can be used to optimise the commercial coating...... process that Tantaline A/S and Alfa Laval (Sweden) use to manufacture tantalum coated plate heat exchangers. Experiments are done by coating the inner side of long, thin stainless steel tubes in the temperature range of 700 – 950 °C and pressure range of 25 – 990 mbar while using different reactant...

  12. Search for narrow resonances below the Upsilon mesons

    Energy Technology Data Exchange (ETDEWEB)

    Apollinari, G.; Barone, M.; Carithers, W.; Dell' Orso, M.; Dorigo, T.; Fiori, I; Franklin, M.; Giannetti, P.; Giromini, P.; Happacher, F.; Miscetti, S.; Parri, A.; Ptohos,; Velev, G.; /Frascati /Fermilab /Harvard U. /LBL, Berkeley /INFN, Pisa /Pisa U. /Pisa, Scuola Normale Superiore /Padua U. /INFN, Padua

    2005-07-01

    The authors have investigated the invariant mass spectrum of dimuons collected by the CDF experiment during the 1992-1995 run of the Fermilab Tevatron collider to improve the limit on the existence of narrow resonances set by the experiments at the SPEAR e{sup +}e{sup -} collider. In the mass range 6.3-9.0 GeV/c{sup 2} they derive an average 90% upper credible limit of 8 eV to the leptonic width of possible resonances. This limit is much worse at the mass of 7.2 GeV/c{sup 2} due to an excess of 250 {+-} 61 events with a width consistent with the detector resolution.

  13. An above-barrier narrow resonance in 15F

    Directory of Open Access Journals (Sweden)

    F. de Grancey

    2016-07-01

    Full Text Available Intense and purified radioactive beam of post-accelerated 14O was used to study the low-lying states in the unbound 15F nucleus. Exploiting resonant elastic scattering in inverse kinematics with a thick target, the second excited state, a resonance at ER=4.757(6(10 MeV with a width of Γ=36(5(14 keV was measured for the first time with high precision. The structure of this narrow above-barrier state in a nucleus located two neutrons beyond the proton drip line was investigated using the Gamow Shell Model in the coupled channel representation with a 12C core and three valence protons. It is found that it is an almost pure wave function of two quasi-bound protons in the 2s1/2 shell.

  14. An above-barrier narrow resonance in $^{15}$F

    CERN Document Server

    De Grancey, F; Santos, F de Oliveira; Davinson, T; Sorlin, O; Angélique, J C; Assié, M; Berthoumieux, E; Borcea, R; Buta, A; Celikovic, I; Chudoba, V; Daugas, J M; Dumitru, G; Fadil, M; Grévy, S; Kiener, J; Lefebvre-Schuhl, A; Michel, N; Mrazek, J; Negoita, F; Okolowicz, J; Pantelica, D; Pellegriti, M G; Perrot, L; Ploszajczak, M; Randisi, G; Ray, I; Roig, O; Rotaru, F; Laurent, M G Saint; Smirnova, N; Stanoiu, M; Stefan, I; Stodel, C; Subotic, K; Tatischeff, V; Thomas, J C; Ujic, P; Wolski, R

    2016-01-01

    Intense and purified radioactive beam of post-accelerated $^{14}$O was used to study the low-lying states in the unbound $^{15}$F nucleus. Exploiting resonant elastic scattering in inverse kinematics with a thick target, the second excited state, a resonance at E$\\_R$=4.757(6)(10)~MeV with a width of $\\Gamma$=36(5)(14)~keV was measured for the first time with high precision. The structure of this narrow above-barrier state in a nucleus located two neutrons beyond the proton drip line was investigated using the Gamow Shell Model in the coupled channel representation with a $^{12}$C core and three valence protons. It is found that it is an almost pure wave function of two quasi-bound protons in the $2s\\_{1/2}$ shell.

  15. Shearing flow from transient bubble oscillations in narrow gaps

    Science.gov (United States)

    Mohammadzadeh, Milad; Li, Fenfang; Ohl, Claus-Dieter

    2017-01-01

    The flow driven by a rapidly expanding and collapsing cavitation bubble in a narrow cylindrical gap is studied with the volume of fluid method. The simulations reveal a developing plug flow during the early expansion followed by flow reversal at later stages. An adverse pressure gradient leads to boundary layer separation and flow reversal, causing large shear stress near the boundaries. Analytical solution to a planar pulsating flow shows qualitative agreement with the CFD results. The shear stress close to boundaries has implications to deformable objects located near the bubble: Experiments reveal that thin, flat biological cells entrained in the boundary layer become stretched, while cells with a larger cross section are mainly transported with the flow.

  16. Supersonic—Subsonic Transition in Relatively Narrow Channels

    Institute of Scientific and Technical Information of China (English)

    RudlfDvorak

    2000-01-01

    The flow structure in relatively narrow channels has a strong three-dimensional character with complex flow phenomena.Including regions of localized spearation.various vortical structures.etc.,all of which have to be considered when dealing with the problem of supersonic-subsonic transition.In this paper only the following three problems are considered:1.the effect of channel width on transition form supersonic to subsonic velocities.2.transition from supersonic to subsonic velocities in a system of shock waves-pseudoshock wave.3.transition from subsonic to supersonic velocities in a critical cross section at the end of a duct with fully developed turbulent channel flow.Problems connectewd with vortical structures and flow separation were discussed by the same author elsewhere (see References).

  17. Density Fluctuations of Hard-Sphere Fluids in Narrow Confinement

    Science.gov (United States)

    Nygârd, Kim; Sarman, Sten; Hyltegren, Kristin; Chodankar, Shirish; Perret, Edith; Buitenhuis, Johan; van der Veen, J. Friso; Kjellander, Roland

    2016-01-01

    Spatial confinement induces microscopic ordering of fluids, which in turn alters many of their dynamic and thermodynamic properties. However, the isothermal compressibility has hitherto been largely overlooked in the literature, despite its obvious connection to the underlying microscopic structure and density fluctuations in confined geometries. Here, we address this issue by probing density profiles and structure factors of hard-sphere fluids in various narrow slits, using x-ray scattering from colloid-filled nanofluidic containers and integral-equation-based statistical mechanics at the level of pair distributions for inhomogeneous fluids. Most importantly, we demonstrate that density fluctuations and isothermal compressibilities in confined fluids can be obtained experimentally from the long-wavelength limit of the structure factor, providing a formally exact and experimentally accessible connection between microscopic structure and macroscopic, thermodynamic properties. Our approach will thus, for example, allow direct experimental verification of theoretically predicted enhanced density fluctuations in liquids near solvophobic interfaces.

  18. Magnetization states and switching in narrow-gapped ferromagnetic nanorings

    Directory of Open Access Journals (Sweden)

    Jie Li

    2012-03-01

    Full Text Available We study permalloy nanorings that are lithographically fabricated with narrow gaps that break the rotational symmetry of the ring while retaining the vortex ground state, using both micromagnetic simulations and magnetic force microscopy (MFM. The vortex chirality in these structures can be readily set with an in-plane magnetic field and easily probed by MFM due to the field associated with the gap, suggesting such rings for possible applications in storage technologies. We find that the gapped ring edge characteristics (i.e., edge profile and gap shape are critical in determining the magnetization switching field, thus elucidating an essential parameter in the controls of devices that might incorporate such structures.

  19. Statistics of narrow-band partially polarized light

    Science.gov (United States)

    Charnotskii, Mikhail

    2017-09-01

    A complete single-point statistical description of a narrow-band partially polarized optical field is developed in terms of the 2D period-averaged probability density function (PA-PDF) of the electrical field vector. This statistic can be measured using the coherent (heterodyne) detection. PA-PDF carries more information about the partially polarized light than the traditional Stokes vector. For a simple Gaussian partially polarized field the PA-PDF depends on 13 real parameters in contrast to the four parameters of the Stokes vector or coherence tensor. We show on several examples that the polarization state of the wave, as described by PA-PDF can vary significantly even while Stokes vector remains fixed.

  20. Formation of the Terrestrial Planets from a Narrow Annulus

    CERN Document Server

    Hansen, Brad

    2009-01-01

    We show that the assembly of the Solar System terrestrial planets can be successfully modelled with all of the mass initially confined to a narrow annulus between 0.7 and 1.0 AU. With this configuration, analogues of Mercury and Mars often form from the collisional evolution of material diffusing out of the annulus under the scattering of the forming Earth and Venus analogues. The final systems also possess eccentricities and inclinations that match the observations, without recourse to dynamical friction from remnant small body populations. Finally, the characteristic assembly timescale for Earth analogues is rapid in this model, and consistent with cosmochemical models based on the $^{182}$Hf--$^{182}$W isotopes. The agreement between this model and the observations suggests that terrestrial planet systems may also be formed in `planet traps', as has been proposed recently for the cores of giant planets in our solar system and others.

  1. Motion tracking in narrow spaces: a structured light approach.

    Science.gov (United States)

    Olesen, Oline Vinter; Paulsen, Rasmus R; Højgaar, Liselotte; Roed, Bjarne; Larsen, Rasmus

    2010-01-01

    We present a novel tracking system for patient head motion inside 3D medical scanners. Currently, the system is targeted at the Siemens High Resolution Research Tomograph (HRRT) PET scanner. Partial face surfaces are reconstructed using a miniaturized structured light system. The reconstructed 3D point clouds are matched to a reference surface using a robust iterative closest point algorithm. A main challenge is the narrow geometry requiring a compact structured light system and an oblique angle of observation. The system is validated using a mannequin head mounted on a rotary stage. We compare the system to a standard optical motion tracker based on a rigid tracking tool. Our system achieves an angular RMSE of 0.11 degrees demonstrating its relevance for motion compensated 3D scan image reconstructions as well as its competitiveness against the standard optical system with an RMSE of 0.08 degrees. Finally, we demonstrate qualitative result on real face motion estimation.

  2. Narrow band interference cancelation in OFDM: Astructured maximum likelihood approach

    KAUST Repository

    Sohail, Muhammad Sadiq

    2012-06-01

    This paper presents a maximum likelihood (ML) approach to mitigate the effect of narrow band interference (NBI) in a zero padded orthogonal frequency division multiplexing (ZP-OFDM) system. The NBI is assumed to be time variant and asynchronous with the frequency grid of the ZP-OFDM system. The proposed structure based technique uses the fact that the NBI signal is sparse as compared to the ZP-OFDM signal in the frequency domain. The structure is also useful in reducing the computational complexity of the proposed method. The paper also presents a data aided approach for improved NBI estimation. The suitability of the proposed method is demonstrated through simulations. © 2012 IEEE.

  3. The narrow range of perceived predation: a 19 group study

    Directory of Open Access Journals (Sweden)

    Olivier Mesly

    2013-05-01

    Full Text Available This paper rests largely on the works of Mesly (1999 to 2012. It argues that the phenomenon of perceived predation as a functional behavioural phenomenon is subjected to certain limits, a finding based on studies performed on 19 different groups spread over a four-year span. It also finds a constant of k = 1.3 which reflects the invariant nature of perceived predation. These findings add to the theory of financial predation which stipulates that financial predators operate below the limits of detection pertaining to their customers (and market regulators. They are experts at minimizing the perception that clients could have that they are after their money, causing them financial harm, by surprise (perceived predation. Understanding the narrow range in which financial predators operate is setting the grounds to offer better protection to investors and to implementing better control and punitive measures.

  4. The Tacoma Narrows Bridge Collapse on Film and Video

    Science.gov (United States)

    Olson, Don; Hook, Joseph; Doescher, Russell; Wolf, Steven

    2015-11-01

    This month marks the 75th anniversary of the Tacoma Narrows Bridge collapse. During a gale on Nov. 7, 1940, the bridge exhibited remarkable oscillations before collapsing spectacularly (Figs. 1-5). Physicists over the years have spent a great deal of time and energy studying this event. By using open-source analysis tools and digitized footage of the disaster, physics students in both high school and college can continue in this tradition. Students can watch footage of "Galloping Gertie," ask scientific questions about the bridge's collapse, analyze data, and draw conclusions from that analysis. Students should be encouraged to pursue their own investigations, but the question that drove our inquiry was this: "When physics classes watch modern video showing the oscillations and the free fall of the bridge fragments, are these scenes sped up, slowed down, or at the correct speed compared to what was observed by the eyewitnesses on Nov. 7, 1940?"

  5. Narrow-line fiber-coupled modules for DPAL pumping

    Science.gov (United States)

    Koenning, Tobias; McCormick, Dan; Irvin, David; Stapleton, Dean; Guiney, Tina; Patterson, Steve

    2015-03-01

    Recent advances in high power diode laser technologies have enabled advanced research on diode pumped alkali metal vapor lasers (DPALs). Due to their low quantum defect, DPALs offer the promise of scalability to very high average power levels while maintaining excellent beam quality. Research is being conducted on a variety of gain media species, requiring different pump wavelengths: near 852nm for cesium, 780nm for rubidium, 766nm for potassium, and 670nm for lithium atoms. The biggest challenge in pumping these materials efficiently is the narrow gain media absorption band of approximately 0.01nm. Typical high power diode lasers achieve spectral widths around 3nm (FWHM) in the near infrared spectrum. Gratings may be used internal or external to the cavity to reduce the spectral width to 0.5nm to 1nm for high power diode laser modules. Recently, experimental results have shown narrower line widths ranging from picometers (pm) at very low power levels to sub-100 picometers for water cooled stacks around 1kW of output power. The focus of this work is a further reduction in the spectral line width of high power diode laser bars emitting at 766nm, with full applicability to other wavelengths of interest. One factor limiting the reduction of the spectral line width is the optical absorption induced thermal gradient inside the volume Bragg grating (VBG). Simulated profiles and demonstrated techniques to minimize thermal gradients will be presented. To enable the next stage of DPAL research, a new series of fiber coupled modules is being introduced featuring greater than 400W from a 600μm core fiber of 0.22NA. The modules achieve a spectral width of <<0.1nm and wavelength tunability of +/- 0.15nm.

  6. Critical heat removal rate through a hemispherical narrow gap

    Energy Technology Data Exchange (ETDEWEB)

    Park, R.J.; Ha, K.S.; Kang, K.H.; Kim, S.B.; Kim, H.D. [Severe Accident Research Project, Korea Atomic Energy Research Institute Yusong, P.O. Box 105, Daejeon (Korea); Jeong, J.H. [Chonan College of Foreign Studies, An-seo-Wong 150, Chun-an (Korea)

    2003-02-01

    An experimental study has been performed to investigate boiling mechanism and to estimate critical heat removal rate from a critical power through a hemispherical narrow gap using distilled water and Freon R-113. The distilled water data on the critical heat removal rate were compared with the R-113 data. The experimental results on the critical heat removal rate were also compared with the existing correlations, developed in flat plate, annuli, and spherical gaps. The test results have shown that a CCFL (Counter Current Flow Limitation) brings about local dryout and finally global dryout in the hemispherical gap thickness of 0.5, 1.0, and 2.0 mm. The boiling mechanism in a hemispherical gap thickness of 5.0 mm is the combination of the CCFL and the pool boiling condition. An increase in gap thickness of 10.0 mm leads to the pool boiling condition rather than the CCFL. Increases in the gap thickness and pressure lead to increase in critical heat removal rate, but the pressure effect on the critical heat removal rate was found to be much milder than the predictions by flat plate and annuli gaps. The measured critical heat removal rate using the R-113 in hemispherical narrow gap thickness of 1.0 and 2.0 mm are 51.5%, 44.5% lower than that using the distilled water due to the lower boiling point and the bubble size, which is different from the pool boiling condition of approximately 14.8%. The measured critical heat removal rate using the R-113 in a gap thickness of 5 mm is 21.6% lower than that using distilled water, which approaches to the pool boiling condition. (orig.)

  7. Keeping the Edges Sharp II: Honing Simulations of Narrow Rings

    Science.gov (United States)

    Rimlinger, Thomas; Hamilton, Douglas; Hahn, Joseph M.

    2016-05-01

    It has long been believed that shepherd satellites are necessary to keep narrow rings confined. While a pair of nearby satellites brackets Saturn’s F ring and Uranus’ Epsilon ring, dozens of other ringlets observed around the outer three planets seem to be unattended. Hamilton et al. (this meeting) have argued analytically that eccentric or inclined rings can maintain their sharp edges for millions or even billions of years despite continually dissipating energy. Here, we present numerical integrations showing isolated eccentric ringlets that do not spread; our model includes only the gravity from an oblate planet, ring self-gravity, and viscosity. We use the symplectic integrator epi_int written by Hahn & Spitale (2013).For narrow rings, the weak perturbation forces that we study act on secular rather than orbital timescales. Therefore, we find that we can use an unusually long timestep, in which these weak forces are applied once every ~30 orbits, with good energy and angular momentum conservation. Long timesteps allow us to run simulations that might otherwise take hours or even days in a matter of minutes. We present comparisons between simulations with identical initial conditions but varying timesteps to show that our approach is appropriate for this class of problems. This technique of speeding up numerical integrations works for any symplectic integrator, requiring only that the forces be weak and that the timescale of interest be long. Problems well suited to this approach (those with only secular and drag forces) include tidally-damped exoplanets and dust grains subject to radiation pressure and Poynting-Robertson drag.

  8. Narrow-track wheeled agricultural tractor parameter variation.

    Science.gov (United States)

    Guzzomi, A; Rondelli, V

    2013-10-01

    Despite a general consensus among farmers, manufacturers, and researchers that wheeled agricultural tractor design has changed over time, there is little published evidence. There is debate as to whether the standardized rollover protective structure (ROPS) energy and force requirements, based on a tractor reference mass and pertaining to studies conducted more than 40 years ago, are appropriate for modern tractors. This article investigated the physical parameters of 326 modern narrow-track tractors, measured according to OECD Code 6 over 16 years (1993 to 2008 inclusive): 252 (-77%) were fixed-chassis tractors and 74 (-23%) were articulated. To understand the significance of design changes, the data were analyzed with respect to time and as a function of tractor mass. Articulated and fixed-chassis data were treated separately. The time data allowed qualitative analysis, while the mass data allowed quantitative analysis. The parameters show some changes over time and clearly indicate differences between articulated and fixed-chassis types. The parameter changes, along with the differences between types, may have important safety ramifications for ROPS energy absorption requirements, and these aspects are discussed. Regression lines with R2 values were fitted to the mass-related data for fixed-chassis and articulated tractors to determine the suitability of fit. The mass relations also displayed differences between fixed-chassis and articulated tractors. Thus, the most significant recommendation from this study is that the standardized testing procedure for narrow-track wheeled agricultural tractor category should be split into two groups: fixed-chassis and articulated.

  9. Narrow-Bandwidth Diode-Laser-Based Ultraviolet Light Source

    Institute of Scientific and Technical Information of China (English)

    PENG Yu; FANG Zhan-Jun; ZANG Er-Jun

    2011-01-01

    A compact, tunable and narrow-bandwidth laser source for ultraviolet radiation is presented. A grating stabilized diode laser at 1064 nm is frequency-stabilized to below 10 kHz by using a ultra low expansion (ULE) cavity. Injecting light of the diode laser into a tapered amplifier yields a power of 290mW. In a first frequency-doubling stage, about 47 mW of green light at 532nm is generated by using a periodical// poled KTP crystal. Subsequent second-harwonic generation employing a BBO crystal leads to about 30μW of ultraviolet light at 266nm.%A compact,tunable and narrow-bandwidth laser source for ultraviolet radiation is presented.A grating stabilized diode laser at 1064nm is frequency-stabilized to below 10kHz by using a ultra low expansion (ULE) cavity.Injecting light of the diode laser into a tapered amplifier yields a power of 290 mW.In a first frequency-doubling stage,about 47mW of green light at 532nm is generated by using a periodically poled KTP crystal.Subsequent second-harmonic generation employing a BBO crystal leads to about 30 μ W of ultraviolet light at 266nm.Hg is,so far,the heaviest nonradioactive atom that has been laser-cooled and trapped.Systematic evaluation of various sources of uncertainty for the Hg-based optical lattice clock is obtained and an accuracy of better than 10-1s is attainable,which is an order of magnitude of improvement over Sr or Yb based clocks because of the reduced susceptibility to the blackbody radiation field,which sets a major limitation on the accuracy of atomic clocks.[1] The 1S0-3p0 transition at 265.6 nm will be exploited as a clock transition.

  10. PULSED KGd(WO42 RAMAN LASER: TOWARDS EMISSION LINEWIDTH NARROWING

    Directory of Open Access Journals (Sweden)

    V. G. Savitski

    2015-01-01

    Full Text Available The linewidth of a KGd(WO42 pulsed Raman laser is analysed experimentally for different configurations of the Raman and pump resonators: with narrow and broadband pump emission profiles, with and without linewidth narrowing elements in the Raman laser resonator, with and without injection seeding into the Raman cavity. The benefits of a narrow linewidth pump source in combination with linewidth narrowing elements in the Raman laser cavity for the efficient linewidth narrowing of the Raman emission are explained. 20 kW peak-power pulses at 1156 nm with 0,43 cm -1 emission linewidth are demonstrated from an injection seeded KGW Raman laser. 

  11. Validation of system codes RELAP5 and SPECTRA for natural convection boiling in narrow channels

    Energy Technology Data Exchange (ETDEWEB)

    Stempniewicz, M.M., E-mail: stempniewicz@nrg.eu; Slootman, M.L.F.; Wiersema, H.T.

    2016-10-15

    Highlights: • Computer codes RELAP5/Mod3.3 and SPECTRA 3.61 validated for boiling in narrow channels. • Validated codes can be used for LOCA analyses in research reactors. • Code validation based on natural convection boiling in narrow channels experiments. - Abstract: Safety analyses of LOCA scenarios in nuclear power plants are performed with so called thermal–hydraulic system codes, such as RELAP5. Such codes are validated for typical fuel geometries applied in nuclear power plants. The question considered by this article is if the codes can be applied for LOCA analyses in research reactors, in particular exceeding CHF in very narrow channels. In order to answer this question, validation calculations were performed with two thermal–hydraulic system codes: RELAP and SPECTRA. The validation was based on natural convection boiling in narrow channels experiments, performed by Prof. Monde et al. in the years 1990–2000. In total 42 vertical tube and annulus experiments were simulated with both codes. A good agreement of the calculated values with the measured data was observed. The main conclusions are: • The computer codes RELAP5/Mod 3.3 (US NRC version) and SPECTRA 3.61 have been validated for natural convection boiling in narrow channels using experiments of Monde. The dimensions applied in the experiments were performed for a range that covers the values observed in typical research reactors. Therefore it is concluded that both codes are validated and can be used for LOCA analyses in research reactors, including natural convection boiling. The applicability range of the present validation is: hydraulic diameters of 1.1 ⩽ D{sub hyd} ⩽ 9.0 mm, heated lengths of 0.1 ⩽ L ⩽ 1.0 m, pressures of 0.10 ⩽ P ⩽ 0.99 MPa. In most calculations the burnout was predicted to occur at lower power than that observed in the experiments. In several cases the burnout was observed at higher power. The overprediction was not larger than 16% in RELAP and 15% in

  12. Simulation of a Narrow Bandpass-Limited Satellite Channel

    Science.gov (United States)

    1976-07-28

    3.2 was the first to be designed [36] and simulated. This linear phase filter is used as a baseline for comparison, especially with respect to...results for nonlinear phase filters . Its frequency response and the associated performance data for B/R = 0.69 and 0.46 are given in Figs, 10-12 of [37...A 1 01 a 0.88 • 076 10 12 (Eb/No»eff Fig. 3.6. BPSK performance for cubic- phase filter , bandpass limiter, random data, and balanced links (36

  13. A luminescence line-narrowing spectroscopic study of the uranium(VI) interaction with cementitious materials and titanium dioxide.

    Science.gov (United States)

    Tits, Jan; Walther, Clemens; Stumpf, Thorsten; Macé, Nathalie; Wieland, Erich

    2015-01-21

    Non-selective luminescence spectroscopy and luminescence line-narrowing spectroscopy were used to study the retention of UO2(2+) on titanium dioxide (TiO2), synthetic calcium silicate hydrate (C-S-H) phases and hardened cement paste (HCP). Non-selective luminescence spectra showed strong inhomogeneous line broadening resulting from a strongly disordered UO2(2+) bonding environment. This problem was largely overcome by using luminescence line-narrowing spectroscopy. This technique allowed unambiguous identification of three different types of UO2(2+) sorbed species on C-S-H phases and HCP. Comparison with spectra of UO2(2+) sorbed onto TiO2 further allowed these species to be assigned to a surface complex, an incorporated species and an uranate-like surface precipitate. This information provides the basis for mechanistic models describing the UO2(2+) sorption onto C-S-H phases and HCP and the assessment of the mobility of this radionuclide in a deep geological repository for low and intermediate level radioactive waste (L/ILW) as this kind of waste is often solidified with cement prior to storage.

  14. Adaptive digital calibration techniques for narrow band low-IF receivers with on-chip PLL

    Institute of Scientific and Technical Information of China (English)

    Li Juan; Zhang Huajiang; Zhao Feng; Hong Zhiliang

    2009-01-01

    Digital calibration and control techniques for narrow band integrated low-IF receivers with on-chip frequency synthesizer are presented. The calibration and control system, which is adopted to ensure an achievable signal-to-noise ratio and bit error rate, consists of a digitally controlled, high resolution dB-linear automatic gain control (AGC), an inphase (I) and quadrature (Q) gain and phase mismatch calibration, and an automatic frequency calibration (AFC) of a wideband voltage-controlled oscillator in a PLL based frequency synthesizer. The calibration system has a low design complexity with little power and small die area. Simulation results show that the calibration system can enlarge the dynamic range to 72 dB and minimize the phase and amplitude imbalance between I and Q to 0.08° and 0.024 dB, respectively, which means the image rejection ratio is better than 60 dB. In addition, the calibration time of the AFC is 1.12μs only with a reference clock of 100 MHz.

  15. Fisheye Photogrammetry: Tests and Methodologies for the Survey of Narrow Spaces

    Science.gov (United States)

    Perfetti, L.; Polari, C.; Fassi, F.

    2017-02-01

    The research illustrated in this article aimed at identifying a good standard methodology to survey very narrow spaces during 3D investigation of Cultural Heritage. It is an important topic in today's era of BIM modelling applied to Cultural Heritage. Spaces like staircases, corridors and passages are very common in the architectural or archaeological fields, and obtaining a 3D-oriented survey of those areas can be a very complex task when completeness of the model and high precision are requested. Photogrammetry appears to be the most promising solution in terms of versatility and manoeuvrability also considering the quality of the required data. Fisheye lenses were studied and tested in depth because of their significant advantage in the field of view if compared with rectilinear lenses. This advantage alone can be crucial to reduce the total amount of photos and, as a consequence, to obtain manageable data, to simplify the survey phase and to significantly reduce the elaboration time. In order to overcome the main issue that arise when using fisheye lenses, which is the lack of rules that can be employed to design the survey, a general mathematical formulation to precisely estimate the GSD (Ground Sampling Distance) for every optical projection is presented here. A complete survey of a real complex case study was performed in order to test and stress the proposed methodology, and to handle a fisheye-based survey from beginning to end: the photogrammetric survey of the Minguzzi Staircase. It is a complex service spiral-staircase located in the Duomo di Milano with a total height of 25 meters and characterized by a narrow walkable space about 70 centimetres wide.

  16. Nonlinear Phase Noise Compensation in Experimental WDM Systems with 256QAM

    DEFF Research Database (Denmark)

    Yankov, Metodi Plamenov; Da Ros, Francesco; Porto da Silva, Edson

    2016-01-01

    Nonlinear phase noise (NLPN) is studied in an experimental wavelength division multiplexed (WDM) system operating at 256QAM. Extremely narrow linewidth lasers (phase part of the nonlinear noise in a Raman amplified link. Based...

  17. Phase transitions in the coal-water-methane system

    Energy Technology Data Exchange (ETDEWEB)

    Alexeev, A.D.; Ulyanova, E.V.; Kalugina, N.A.; Degtyar, S.E. [Institute of Physical & Mining Processes, Donetsk (Ukraine)

    2006-07-01

    Low temperature phase transitions in water and methane occurring in fossil coals were studied experimentally using Nuclear Magnetic Resonance (NMR) techniques. Contributions of constituent fluids into narrow line of {sup 1}H NMR wide line spectrum were analyzed.

  18. 空气预热器烟气入口增设非平衡换热器的可行性分析%Feasibility of adding non-balance heat exchanger at gas inlet of air preheater

    Institute of Scientific and Technical Information of China (English)

    王春昌

    2014-01-01

    Against the rotating characteristics,low temperature corrosion ash deposition perform-ance and outlet gas temperature distribution rule of the rotary air preheater,it suggests non-bal-ance heat exchanger be added at the air preheater inlet and the flue duct be divided into several small ones.By properly reducing the inlet gas temperature of each small flue duct,the boiler ex-haust temperature becomes equilibrium and decreases on a whole.Finally,the boiler exhaust tem-perature can be reduced and the boiler efficiency and unit heat efficiency can be enhanced.%针对回转式空气预热器的旋转特性、低温腐蚀堵灰特征以及出口烟气温度分布规律,提出了在空气预热器入口设置非平衡换热器,将烟道分隔为几个小烟道,通过适度地降低各个小烟道的入口烟气温度,使锅炉排烟温度分布趋于平衡并整体有所降低,最终达到进一步降低锅炉排烟温度的目的,提高锅炉热效率或机组热效率。

  19. Different mechanisms underlying the repolarization of narrow and wide action potentials in pyramidal cells and interneurons of cat motor cortex.

    Science.gov (United States)

    Chen, W; Zhang, J J; Hu, G Y; Wu, C P

    1996-07-01

    Two different types of action potentials were observed among the pyramidal cells and interneurons in cat motor cortex: the narrow action potentials and the wide action potentials. These two types of action potentials had similar rising phases (528.8 +/- 77.0 vs 553.1 +/- 71.8 mV/ms for the maximal rising rate), but differed in spike duration (0.44 +/- 0.09 vs 1.40 +/- 0.39 ms) and amplitude (57.31 +/- 8.22 vs 72.52 +/- 8.31 mV), implying that the ionic currents contributing to repolarization of these action potentials are different. Here we address this issue by pharmacological manipulation and using voltage-clamp technique in slices of cat motor cortex. Raising extracellular K+ concentration (from 3 mM to 10 mM), applying a low dose of 4-aminopyridine (2-200 microM) or administering a low concentration of tetraethylammonium (0.2-1.0 mM) each not only broadened the narrow action potentials, but also increased their amplitudes. In contrast, high K+ medium or low dose of tetraethylammonium only broadened the wide action potentials, leaving their amplitudes unaffected, and 4-aminopyridine had only a slight broadening effect on the wide spikes. These results implied that K+ currents were involved in the repolarization of both types of action potentials, and that the K+ currents in the narrow action potentials seemed to activate much earlier than those in the wide spikes. This early activated K+ current may counteract the rapid sodium current, yielding the extremely brief duration and small amplitude of the narrow spikes. The sensitivity of the narrow spikes to 4-aminopyridine may not be mainly attributed to blockade of the classical A current (IA), because depolarizing the membrane potential to inactivate IA did not reproduce the effects of 4-aminopyridine. Blockade of Ca2+ influx slowed the last two-thirds repolarization of the wide action potentials. On the contrary, the narrow action potentials were not affected by Ca(2+)-current blockers, but if they were first

  20. Lewis acid adducts of narrow band gap conjugated polymers.

    Science.gov (United States)

    Welch, Gregory C; Bazan, Guillermo C

    2011-03-30

    We report on the interaction of Lewis acids with narrow band gap conjugated copolymers containing donor and acceptor units. Examination of the widely used poly[(4,4-bis(2-ethylhexyl)cyclopenta-[2,1-b:3,4-b']dithiophene)-2,6-(diyl-alt-benzo[2,1,3]thiadiazole)-4,7-diyl] (1) shows weaker binding with B(C(6)F(5))(3) when compared with a small molecule that contains a cyclopenta-[2,1-b:3,4-b']dithiophene (CDT) unit flanked by two benzo[2,1,3]thiadiazole (BT) fragments. Studies on model compounds representative of 1, together with a comparison between B(C(6)F(5))(3) and BBr(3), indicate that the propensity for Lewis acid coordination is decreased because of steric encumbrance surrounding the BT nitrogen sites. These observations led to the design of chromophores that incorporate an acceptor unit with a more basic nitrogen site, namely pyridal[2,1,3]thiadiazole (PT). That this strategy leads to a stronger B-N interaction was demonstrated through the examination of the reaction of B(C(6)F(5))(3) with two small molecules bis(4,4-bis(hexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-4,7-pyridal[2,1,3]thiadiazole (8) and bis{2-thienyl-(4,4-bis(hexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)}-4,7-pyridal[2,1,3]thiadiazole (9) and two polymer systems (poly[(4,4-bis(2-ethylhexyl)cyclopenta-[2,1-b:3,4-b']dithiophene)-2,6-diyl-alt-([1,2,5]thiadiazolo[3,4-c]pyridine)-4,7-diyl] (10) and poly[(4,4-bis(2-ethylhexyl)cyclopenta-[2,1-b:3,4-b']dithiophene)-2,6-diyl-alt-(4',7'-bis(2-thienyl)-[1,2,5]thiadiazolo[3,4-c]pyridine)-5,5-diyl] (11). From a materials perspective, it is worth pointing out that through the binding of B(C(6)F(5))(3), new NIR-absorbing polymers can be generated with band gaps from 1.31 to 0.89 eV. A combination of studies involving ultraviolet photoemission spectroscopy and density functional theory shows that the narrowing of the band gap upon borane coordination to the pyridal nitrogen on PT is a result of lowering the energies of both the highest occupied molecular

  1. Preheating of coal. Its influence on the composition of coal, the quality of coke and on the phenomenon of pushing. Precalentado del carbon. Su influencia en la composicion del carbon, en la calidad del coque y en el fenomeno del empuje

    Energy Technology Data Exchange (ETDEWEB)

    1994-01-01

    A comparative study of the carbonization of a wide range of coals, wet and after preheating, was carried out. The 6 t coal capacity oven of the INCAR Experimental Coking Test Plant and the 2 t/h preheating pilot plant, Precarbon process, installed by ENSIDESA annexed to the INCAR plant were used. Influence of the preheating process on coal plastic properties was followed through Arnu dilatation, Gieseler fluidity and swelling index tests. Structural modifications of the coals were examined by FT-IR. Coal samples [lt]0.15 mm that do not need to be crushed for analysis and Arnu dilatation were chosen. A Koppers-INCAR test of all coals studied was carried out. Cokes obtained were characterized by optical microscopy, SEM and image analysis. Size analysis, coke strength (Micum e Irsid tests), reactivity and post-reaction strength, chemical changes and porosity were also determined. 21 refs., 36 figs., 9 tabs.

  2. Phases and Phase Transitions

    Science.gov (United States)

    Gitterman, Moshe

    2014-09-01

    In discussing phase transitions, the first thing that we have to do is to define a phase. This is a concept from thermodynamics and statistical mechanics, where a phase is defined as a homogeneous system. As a simple example, let us consider instant coffee. This consists of coffee powder dissolved in water, and after stirring it we have a homogeneous mixture, i.e., a single phase. If we add to a cup of coffee a spoonful of sugar and stir it well, we still have a single phase -- sweet coffee. However, if we add ten spoonfuls of sugar, then the contents of the cup will no longer be homogeneous, but rather a mixture of two homogeneous systems or phases, sweet liquid coffee on top and coffee-flavored wet sugar at the bottom...

  3. Recovering physical properties from narrow-band photometry

    CERN Document Server

    Schoenell, William; Benítez, Narciso; Asari, Natalia Vale

    2012-01-01

    Our aim in this work is to answer, using simulated narrow-band photometry data, the following general question: What can we learn about galaxies from these new generation cosmological surveys? For instance, can we estimate stellar age and metallicity distributions? Can we separate star-forming galaxies from AGN? Can we measure emission lines, nebular abundances and extinction? With what precision? To accomplish this, we selected a sample of about 300k galaxies with good S/N from the SDSS and divided them in two groups: 200k objects and a template library of 100k. We corrected the spectra to $z = 0$ and converted them to filter fluxes. Using a statistical approach, we calculated a Probability Distribution Function (PDF) for each property of each object and the library. Since we have the properties of all the data from the {\\sc starlight}-SDSS database, we could compare them with the results obtained from summaries of the PDF (mean, median, etc). Our results shows that we retrieve the weighted average of the lo...

  4. Narrow-K-Band Observations of the GJ 1214 System

    CERN Document Server

    Colon, Knicole D

    2013-01-01

    GJ 1214 is a nearby M dwarf star that hosts a transiting super-Earth-size planet, making this system an excellent target for atmospheric studies. Most studies find that the transmission spectrum of GJ 1214b is flat, which favors either a high mean molecular weight or cloudy/hazy hydrogen (H) rich atmosphere model. Photometry at short wavelengths (< 0.7 micron) and in the K-band can discriminate the most between these different atmosphere models for GJ 1214b, but current observations do not have sufficiently high precision. We present photometry of seven transits of GJ 1214b through a narrow K-band (2.141 micron) filter with the Wide Field Camera on the 3.8 m United Kingdom Infrared Telescope. Our photometric precision is typically 1.7x10^-3 (for a single transit), comparable with other ground-based observations of GJ 1214b. We measure a planet-star radius ratio of 0.1158+/-0.0013, which, along with other studies, also supports a flat transmission spectrum for GJ 1214b. Since this does not exclude a scenari...

  5. Effect of an interband interaction on narrow-band superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Ajay; Patra, S.; Tripathi, R.S. [Department of Physics, Govind Ballabh Pant University of Agriculture & Technology, Pantnagar 263145 (India)

    1995-05-01

    The effect of an interband interaction ({ital U}{sub {ital s}{ital d}}) on narrow-band superconductivity in the presence of weak hybridization has been studied by extending the Anderson lattice Hamiltonian. We have employed Zubarev`s double-time Green`s-function technique and used a mean-field decoupling scheme to obtain the self-consistent expressions for the transition temperature ({ital T}{sub {ital c}}) and interband correlation parameter ({gamma}{sub {ital c}}). The {ital T}{sub {ital c}} is found to be dependent on both the interband interaction and on the strength of the hybridization between {ital s}- (or {ital p}-) and {ital d}-band electrons (within a two-band model). We have shown that the interband interaction ({ital U}{sub {ital s}{ital d}}) plays qualitatively the same role as that of hybridization ({ital V}). Finally, we have explained the relevance of our results in transition metals or electron-doped high-{ital T}{sub {ital c}} superconductors under externally applied pressure.

  6. Narrow-band ELF events observed from South Pole Station

    Science.gov (United States)

    Heavisides, J.; Weaver, C.; Lessard, M.; Weatherwax, A. T.

    2012-12-01

    Extremely Low Frequency (ELF) waves are typically in the range of 3 Hz - 3 kHz and can play a role in acceleration and pitch-angle scattering of energetic particles in the radiation belts. Observations of a not uncommon, but not well studied ELF phenomenon are presented with ground-based data from South Pole Station. The narrow-band waves last approximately one or two minutes maintaining bandwidth over the course of the event, begin around 100 Hz, decrease to about 70 Hz, and typically show a higher frequency harmonic. The waves have only been documented at four locations - Heacock, 1974 (Alaska); Sentman and Ehring, 1994 (California); Wang et al, 2005 and Wang et al, 2011 (Taiwan); and Kim et al, 2006 (South Pole). The waves observed at the South Pole are not detected when the Sun drops below a 10 degree elevation angle, which is not true for the other locations. We extend the study of Kim et al, 2006, and explore possible generation mechanisms including sunlit ionosphere and ion cyclotron wave modes, as well as correspondence with energetic particle precipitation.

  7. Modular design of long narrow scintillating cells for ILC detector

    Energy Technology Data Exchange (ETDEWEB)

    Beznosko, D.; Blazey, G.; Dyshkant, A.; Maloney, J.; Rykalin, V.; /Northern Illinois U.; Schellpfeffer, J.; /Fermilab

    2005-09-01

    The experimental results for the narrow scintillating elements with effective area about 20 cm{sup 2} are reported. The elements were formed from the single piece of scintillator and were read out via wavelength shifting fibers with the MRS (Metal/Resistor/Semiconductor) photodiodes on both ends of each fiber. The formation of the cells from the piece of scintillator by using grooves is discussed. The cell performance was tested using the radioactive source by measuring the PMT current and a single rate after amplifier and discrimination with threshold at about three photo electrons in each channel and quad coincidences (double coincidences between sensors on each fiber and double coincidences between two neighboring fibers). This result is of high importance for large multi-channel systems, i.e. module may be used as an active element for calorimeter or muon system for the design of the future electron-positron linear collider detector because cell effective area can be smoothly enlarged or reduced (to 4 cm{sup 2} definitely).

  8. Statistical multifrequency study of narrow-line Seyfert 1 galaxies

    CERN Document Server

    Järvelä, Emilia; León-Tavares, Jonathan

    2014-01-01

    High-energy {\\gamma}-rays, which are produced by powerful relativistic jets, are usually associated with blazars and radio galaxies. In the current active galactic nuclei (AGN) paradigm, such jets are almost exclusively launched from massive elliptical galaxies. Recently, however, Fermi/LAT detected {\\gamma}-rays from a few narrow-line Seyfert 1 galaxies and thus confirmed the presence of relativistic jets in them. Since NLS1 galaxies are assumed to be young evolving AGN, they offer a unique opportunity to study the production of relativistic jets in late-type galaxies. Our aim is to estimate by which processes the emission of various kinds is produced in NLS1 galaxies and to study how emission properties are connected to other intrinsic AGN properties. We have compiled the so far largest multiwavelength database of NLS1 sources. This allowed us to explore correlations between different wavebands and source properties using, for example, Pearson and Spearman correlations and principal component analysis. We d...

  9. Voicing Strategies Employed in Narrow Listening Among Iranian Female Freshmen

    Directory of Open Access Journals (Sweden)

    Mohsen Shahrokhi

    2013-05-01

    Full Text Available This study discusses the findings of a qualitative study on the strategies used by Iranian female freshmen in narrow listening. The data collected through semi-structured interview with 12 female freshmen (four learners as  advanced, four as intermediate and four as low chosen purposefully based on their scores in the Oxford Placement Test administered. Six out of 12 freshmen were identified for the think-aloud protocol to draw out the strategies they used. The data collected were analyzed using open, axial, and selective-coding. The analysis of the participants’ interview and think-aloud protocol data generated 12 major themes. Five themes (attention, readiness, evaluating, autonomous learning, and change the speech rate described meta-cognitive; five themes (imitating and repeating, references, visualization, making notes while listening and word-by-word and sentence-by-sentence attention described cognitive strategies and two themes (asking for help, self-talk described socio-affective strategies. These strategies need to be taught explicitly to increase learners’ understanding of the spoken texts in the second/foreign language. This study recommends that Iranian EFL female freshman university learners’ top-down, bottom-up processing and listening strategy awareness should be cultivated and integrated into the teaching of listening to improve the learners’ listening ability.

  10. Narrow-line HI and cold structures in the ISM

    CERN Document Server

    Haud, Urmas

    2013-01-01

    Context. In the HI line profiles in the Leiden-Argentina-Bonn (LAB) all-sky database, we have found a population of very cold HI clouds. So far, the role of these clouds in the interstellar medium (ISM) has remained unclear. Aims. In this paper, we attempt to confirm the existence of the narrow-line HI emission (NHIE) clouds by using the data from the Parkes Galactic all-sky survey (GASS) and try to find their place among other coldest constituents of the ISM. Methods. We repeat the search of NHIE with the GASS data and derive or compile some preliminary estimates for the distribution, temperatures, distances, linear sizes, column and number densities, masses, and the composition of NHIE clouds, and compare these data with corresponding estimates for HI self-absorption (HISA) features, the Planck cold clumps (CC), and infrared dark clouds (IRDC). Results. We demonstrate that from LAB and GASS we can separate comparable NHIE complexes, and the properties of the obtained NHIE clouds are very similar to those of...

  11. The Use of Narrow Diameter Implants in the Molar Area

    Directory of Open Access Journals (Sweden)

    M. Saad

    2016-01-01

    Full Text Available Implant rehabilitations in the posterior jaw are influenced by many factors such as the condition of the remaining teeth, the force factors related to the patient, the quality of the bone, the maintenance of the hygiene, the limited bone height, the type and extent of edentulism, and the nature of the opposing arch. The gold standard is to place a regular diameter implant (>3.7 mm or a wide one to replace every missing molar. Unfortunately, due to horizontal bone resorption, this option is not possible without lateral bone augmentation. In this situation, narrow diameter implant (NDI < 3.5 mm could be the alternative to lateral bone augmentation procedures. This paper presents a clinical study where NDIs were used for the replacement of missing molars. They were followed up to 11 years. Special considerations were observed and many parameters were evaluated. NDI could be used to replace missing molar in case of moderate horizontal bone resorption if strict guidelines are respected. Yet, future controlled prospective clinical trials are required to admit their use as scientific evidence.

  12. Probing Quasar Outflows with Intrinsic Narrow Absorption Lines

    CERN Document Server

    Misawa, T; Charlton, J C; Ganguly, R; Tytler, D; Kirkman, D; Suzuki, N; Lubin, D

    2006-01-01

    We present statistical and monitoring results of narrow absorption lines that are physically related to quasars (i.e., intrinsic NALs). We use Keck/HIRES spectra of 37 optically bright quasars at z=2-4, and identify 150 NAL systems that contain 124 C IV, 12 N V, and 50 Si IV doublets. Among them, 39 are classified as intrinsic systems based on partial coverage analysis. At least 50% of quasars host intrinsic NALs. We identify two families of intrinsic systems based on their ionization state. Some intrinsic systems have detectable low-ionization NALs at similar velocities as higher-ionization NALs, although such low-ionization lines are rare in broad absorption line (BAL) systems. We also have observed an optically bright quasar, HS1603+3820, eight times with Subaru/HDS and HET/MRS over an interval of 4.2 years (1.2 years in the quasar rest frame), for the purpose of monitoring a variable C IV mini-BAL system. We find that all the troughs of the system vary in concert. However, no other correlations are seen b...

  13. Properties of the narrow line Seyfert 1 galaxies revisited

    CERN Document Server

    Liu, Xiang; Su, Renzhi; Zhang, Zhen

    2016-01-01

    There is growing evidence to suggest that the black hole mass has been previously underestimated with the H$\\beta$ line width for certain active galactic nuclei (AGN). With the assumption of the flatter rather than isotropic velocity distribution of gases in the broad-line region of AGN, we investigated the properties of narrow line Seyfert 1 (NLS1) galaxies, like the black hole mass and the Eddington ratio, and compared with broad line Seyfert 1 (BLS1) galaxies. Since gamma-rays detected in a few NLS1s which favor a smaller viewing angle in NLS1s than BLS1s, with the projection effect we estimated the relative black hole mass and Eddington ratio for NLS1s and BLS1s. The result implies that the NLS1s and BLS1s have similar black hole masses and Eddington ratios, peaked at a larger black hole mass and lower Eddington ratio for the NLS1s than thought before. Furthermore, with applying the correction factor 6 of average black hole mass as derived from the modelling of both optical and UV data in radio loud NLS1s...

  14. Narrow-band Imagery of the ISM using the RCT

    Science.gov (United States)

    Walter, D. K.; Gelderman, R.; Guinan, E.; Howell, S.; Mattox, J. R.; McGruder, C. H., III; Davis, D.; Everett, M.

    2003-05-01

    We present the first results of imaging the Interstellar Medium (ISM) using narrow-band filters with the Robotically Controlled Telescope (RCT). The RCT is the recently refurbished 1.3-meter telescope at the Kitt Peak National Observatory. Details regarding the RCT can be found elsewhere at this meeting (Gelderman, R. et al.). Our filters are centered on diagnostic, nebular emission lines of the ions H+, He+, S+, N+ and O++. Objects of interest in the galactic and extragalactic ISM were observed including the starburst galaxy NGC 4449. Ionization ratio maps include [OIII]/Hβ, [NII]/Hα and the C(Hβ) extinction map from the ratio of Hα/Hβ. Electron densities are derived from the ratio of images taken through filters centered on the sulfur lines at 671.7 and 673.1 nm. Refurbishment of the RCT has been made possible by NASA NAG 58-762. Funding for filters and additional equipment has been made possible by NASA OSS NAG 5-10145 and NASA MU-SPIN NCC 5-534.

  15. Using Narrow Band Photometry to Classify Stars and Brown Dwarfs

    CERN Document Server

    Mainzer, A K; Sievers, J L; Young, E T; Lean, Ian S. Mc

    2004-01-01

    We present a new system of narrow band filters in the near infrared that can be used to classify stars and brown dwarfs. This set of four filters, spanning the H band, can be used to identify molecular features unique to brown dwarfs, such as H2O and CH4. The four filters are centered at 1.495 um (H2O), 1.595 um (continuum), 1.66 um (CH4), and 1.75 um (H2O). Using two H2O filters allows us to solve for individual objects' reddenings. This can be accomplished by constructing a color-color-color cube and rotating it until the reddening vector disappears. We created a model of predicted color-color-color values for different spectral types by integrating filter bandpass data with spectra of known stars and brown dwarfs. We validated this model by making photometric measurements of seven known L and T dwarfs, ranging from L1 - T7.5. The photometric measurements agree with the model to within +/-0.1 mag, allowing us to create spectral indices for different spectral types. We can classify A through early M stars to...

  16. Giant Hall Photoconductivity in Narrow-Gapped Dirac Materials.

    Science.gov (United States)

    Song, Justin C W; Kats, Mikhail A

    2016-12-14

    Carrier dynamics acquire a new character in the presence of Bloch-band Berry curvature, which naturally arises in gapped Dirac materials (GDMs). Here, we argue that photoresponse in GDMs with small band gaps is dramatically enhanced by Berry curvature. This manifests in a giant and saturable Hall photoconductivity when illuminated by circularly polarized light. Unlike Hall motion arising from a Lorentz force in a magnetic field, which impedes longitudinal carrier motion, Hall photoconductivity arising from Berry curvature can boost longitudinal carrier transport. In GDMs, this results in a helicity-dependent photoresponse in the Hall regime, where photoconductivity is dominated by its Hall component. We find that the induced Hall conductivity per incident irradiance is enhanced by up to 6 orders of magnitude when moving from the visible regime (with corresponding band gaps) to the far infrared. These results suggest that narrow-gap GDMs are an ideal test-bed for the unique physics that arise in the presence of Berry curvature and open a new avenue for infrared and terahertz optoelectronics.

  17. The HST view of the innermost narrow line region

    CERN Document Server

    Balmaverde, B; Moisio, D; Baldi, R D; Marconi, A

    2016-01-01

    We analyze the properties of the innermost narrow line region in a sample of low-luminosity AGN. We select 33 LINERs (bona fide AGN) and Seyfert galaxies from the optical spectroscopic Palomar survey observed by HST/STIS. We find that in LINERs the [NII] and [OI] lines are broader than the [SII] line and that the [NII]/[SII] flux ratio increases when moving from ground-based to HST spectra. This effect is more pronounced considering the wings of the lines. Our interpretation is that, as a result of superior HST spatial resolution, we isolate a compact region of dense ionized gas in LINERs, located at a typical distance of about 3 pc and with a gas density of about 10$^4$-10$^5$ cm$^{-3}$, which we identify with the outer portion of the intermediate line region (ILR). Instead, we do not observe these kinds of effects in Seyferts; this may be the result of a stronger dilution from the NLR emission, since the HST slit maps a larger region in these sources. Alternatively, we argue that the innermost, higher densi...

  18. Optical Variability of Narrow-Line Seyfert 1 Galaxies

    CERN Document Server

    Klimek, E S; Hedrick, C H; Klimek, Elizabeth S.

    2004-01-01

    We present results of a broad-band photometric study of the optical variability of six Narrow-Line Seyfert 1 (NLS1) galaxies observed at 172 epochs. We searched for microvariability on 33 nights. Strong evidence for microvariability was found only for our lowest luminosity object, NGC 4051, on one night. Weaker evidence suggests such variability on a few other nights for two other objects, but the data are not as convincing. Intra-night variability in NLS1s is thus concluded to be rare and of low amplitude. We give illustrations of how variable image quality can produce spurious variability. We find that for well-studied non-NLS1s there is a spread in the amplitude of seasonal variability (i.e., in some years an AGN is more variable than in others). We find that the means of the variability amplitudes of non-NLS1s over several seasons vary from object to object (i.e., some AGNs are, on average, more variable than others). NLS1s also show a spread in seasonal variabilities. The best-studied NLS1, Ark 564, show...

  19. Assembly auxiliary system for narrow cabins of spacecraft

    Science.gov (United States)

    Liu, Yi; Li, Shiqi; Wang, Junfeng

    2015-09-01

    Due to the narrow space and complex structure of spacecraft cabin, the existing asssembly systems can not well suit for the assembly process of cabin products. This paper aims to introduce an assembly auxiliary system for cabin products. A hierarchical-classification method is proposed to re-adjust the initial assembly relationship of cabin into a new hierarchical structure for efficient assembly planning. An improved ant colony algorithm based on three assembly principles is established for searching a optimizational assembly sequence of cabin parts. A mixed reality assembly environment is constructed with enhanced information to promote interaction efficiency of assembly training and guidance. Based on the machine vision technology, the inspection of left redundant objects and measurement of parts distance in inner cabin are efficiently performed. The proposed system has been applied to the assembly work of a spacecraft cabin with 107 parts, which includes cabin assembly planning, assembly training and assembly quality inspection. The application result indicates that the proposed system can be an effective assistant tool to cabin assembly works and provide an intuitive and real assembly experience for workers. This paper presents an assembly auxiliary system for spacecraft cabin products, which can provide technical support to the spacecraft cabin assembly industry.

  20. Increasing antimicrobial resistance and narrowing therapeutics in typhoidal salmonellae.

    Science.gov (United States)

    Kaurthe, Jaspal

    2013-03-01

    Multidrug-resistant typhoid fever (MDRTF) is a major public health problem in developing countries and is an emerging problem in the developed world. Because of the difficulties in preventing typhoid by public health measures or immunization in developing countries, great reliance is placed on antimicrobial chemotherapy. The treatment should commence as soon as the clinical diagnosis is made rather than after the results of antimicrobial susceptibility tests but the existence of MDRTF poses a serious clinical dilemma in the selection of empiric antimicrobial therapy. With the widespread emergence and spread of strains resistant to chloramphenicol, ampicillin and trimethoprim, ciprofloxacin became the drug of choice for the treatment of typhoid fever. However, of late the efficacy of fluoroquinolones too has been questioned, mainly due to increasing reports of increasing defervescence time and poor patient response. This indicates that the organism has begun to develop resistance to fluoroquinolones, and is corroborated by a steady increase in Minimum Inhibitory Concentration (MIC) of ciprofloxacin. The therapeutics of ciprofloxacin-resistant enteric fever narrows down to third- and fourth-generation cephalosporins and azithromycin. However, the emergence of extended-spectrum b-lactamases (ESBLs) in typhoidal Salmonellae poses a new challenge and would greatly limit the therapeutic options leaving only tigecycline and carbepenems as secondary antimicrobial drugs. This increasing resistance is alarming and emphasizes the need of effective preventive measures to control typhoid and to limit the unnecessary use of antibiotics.

  1. The Meteorology of Storms that Produce Narrow Bipolar Events

    Science.gov (United States)

    Lang, Timothy J.; McCaul, Eugene W.; Cummer, Steven A.

    2013-01-01

    Narrow Bipolar Events (NBEs) are compact intracloud discharges that produce the most powerful lightning-related radio frequency signals that have been observed. However, their luminosity is below the threshold for detectability from current and past spaceborne optical sensors. NBEs have been loosely associated with convective intensity, but their occurrence tends to be highly localized in time and space within a thunderstorm, and there remain many questions about whether and to what extent they are significantly related to meteorological processes within thunderstorms. Using the North Alabama Lightning Mapping Array (NALMA), the National Lightning Detection Network, and available Doppler and polarimetric radar data, case studies will be presented for storm events that produced large numbers of NBEs (10s-100s) during their lifetimes. NBEs are documented via a method that identifies high peak power (>40-50 dBW) initial VHF sources within a specific altitude band in the upper levels of thunderstorms. The production of NBEs, including spatial and temporal variability, will be compared to the radar-inferred kinematic and microphysical structure and evolution of thunderstorms, as well as their NALMA- and NLDN-inferred electrical characteristics. The results should provide new insights into the relationships between NBEs and thunderstorm processes.

  2. Narrow band gap conjugated polymers for emergent optoelectronic technologies

    Science.gov (United States)

    Azoulay, Jason D.; Zhang, Benjamin A.; London, Alexander E.

    2015-09-01

    Conjugated organic molecules effectively produce and harvest visible light and find utility in a variety of emergent optoelectronic technologies. There is currently interest in expanding the scope of these materials to extend functionality into the infrared (IR) spectral regions and endow functionality relevant in emergent technologies. Developing an understanding of the interplay between chemical and electronic structure in these systems will require control of the frontier orbital energetics (separation, position, and alignment), ground state electronic configurations, interchain arrangements, solid-state properties, and many other molecular features with synthetic precision that has yet to be demonstrated. Bridgehead imine substituted 4H-cyclopenta[2,1-b:3,4-b']dithiophene (CPDT) structural units, in combination with strong acceptors with progressively delocalized π-systems, afford modular donor-acceptor copolymers with broad and long wavelength absorption that spans technologically relevant wavelength (λ) ranges from 0.7 < λ < 3.2 μm.1 Here we demonstrate that electronic and structural manipulation play a major role in influencing the energetics of these systems and ultimately controlling the band gap of the materials. These results bear implication in the development of very narrow band gap systems where precise control will be necessary for achieving desired properties such as interactions with longer wavelength light.

  3. Temporal and dynamical spectral analysis of select narrow line Seyfert 1 galaxies

    Science.gov (United States)

    Liebmann, Andrew Cargill

    2010-12-01

    Presented is the detailed analysis of three Narrow Line Seyfert 1 galaxies using the method of dynamical spectral analysis. These are NGC 4051, IRAS F12397+3333 and Mrk 766. The highly variable NGC 4051 exhibits some dramatic changes over the course of two observations. These dramatic changes are attributed to a variable emission region being partially covered by a fixed, thick absorbing cloud. A unique time region was found where the emission region becomes smaller than the absorbing cloud. Source enters a true minimal phase and appears quite stable, appearing to "turn off." When in its lowest flux states NGC 4051 has a thermal plasma feature suggesting starburst activity in the nucleus. The possibility of starburst activity proves an important link in the understanding of the evolution of Active Galactic Nuclei. IRAS F12397+3333, a little studied source, was found to possess a complex, dusty, warm absorber spectrum of helium- and hydrogen-like carbon, nitrogen, oxygen, neon and several ionic species of iron. This is similar to the spectrum of IRAS 13349+2348. A two-phase gas was used to model this spectrum. The location of the gas is consistent with being located in the narrow line region. Two types of variability were found in the rapidly varying Mrk 766. The long-term variability and its associated spectral flattening seen in two observations are caused by a thick partially covering cloud and variable emission region. However the average spectral behavior shows partial covering of a thinner cloud. The result is a "lumpy cloud." When the source is dim a thicker portion of the clouds covers it, but as the source brightens and enlarges the thinner portion plays a more dominant role in the covering. The short, rapid variability is caused by the combination of a highly variable power law component and a stable reflected component, referred to here as ionized relativistic reflection. Finally, some unique flares were discovered. Unlike the other flares seen in the

  4. Vascular contrast in narrow-band and white light imaging.

    Science.gov (United States)

    Du Le, V N; Wang, Quanzeng; Gould, Taylor; Ramella-Roman, Jessica C; Pfefer, T Joshua

    2014-06-20

    Narrow-band imaging (NBI) is a spectrally selective reflectance imaging technique that is used clinically for enhancing visualization of superficial vasculature and has shown promise for applications such as early endoscopic detection of gastrointestinal neoplasia. We have studied the effect of vessel geometry and illumination wavelength on vascular contrast using idealized geometries in order to more quantitatively understand NBI and broadband or white light imaging of mucosal tissue. Simulations were performed using a three-dimensional, voxel-based Monte Carlo model incorporating discrete vessels. In all cases, either 415 or 540 nm illumination produced higher contrast than white light, yet white light did not always produce the lowest contrast. White light produced the lowest contrast for small vessels and intermediate contrast for large vessels (diameter≥100  μm) at deep regions (vessel depth≥200  μm). The results show that 415 nm illuminations provided superior contrast for smaller vessels at shallow depths while 540 nm provided superior contrast for larger vessels in deep regions. Besides 540 nm, our studies also indicate the potential of other wavelengths to achieve high contrast of large vessels at deep regions. Simulation results indicate the importance of three key mechanisms in determining spectral variations in contrast: intravascular hemoglobin (Hb) absorption in the vessel of interest, diffuse Hb absorption from collateral vasculature, and bulk tissue scattering. Measurements of NBI contrast in turbid phantoms incorporating 0.1-mm-diameter hemoglobin-filled capillary tubes indicated good agreement with modeling results. These results provide quantitative insights into light-tissue interactions and the effect of device and tissue properties on NBI performance.

  5. A search for narrow states in radiative upsilon decays

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, S.T.

    1986-12-01

    A search for new states produced in radiative UPSILON(1S) decays is accomplished by observing the inclusive photon energy spectrum. A narrow resonance in the energy spectrum indicates the existence of a new state X produced by the process UPSILON ..-->.. ..gamma..X. The analysis is based on approximately 0.44 x 10/sup 6/ UPSILON(1S) events produced at the DORIS II e/sup +/e/sup -/ storage ring. These data were collected with the Crystal Ball detector between April 1983 and May 1986. This analysis finds no evidence for a new state, so upper limits on the branching ratio BR(UPSILON ..-->.. ..gamma..X) are derived, assuming the state X decays primarily to high-multiplicity hadronic final states. In particular, if the state X were a minimal Higgs particle, its primary decay mode would be to the heaviest fermion-antifermion pair energetically available. For the radiative UPSILON(1S) decays studied here, the heavy fermions would be c anti c or s anti s quark states, over most of the relevant Higgs' mass range. The resulting upper limit for BR(UPSILON(1S) ..-->.. ..gamma..X) is highly energy dependent but for X mass between 1.5 GeV and 8.0 GeV, the 90% confidence level upper limit is better than 8.0 x 10/sup -4/. For a Higgs' mass near 5.0 GeV, the upper limit is about 2.0 x 10/sup -4/ which is approximately equal to the lowest order calculation for the Wilczek mechanism. The Wilczek calculation with QCD radiative corrections predict branching ratios below the limits set here for all Higgs' masses.

  6. Narrowing the uncertainty for deep-ocean injection efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Orr, J.C.; Aumont, O. [Laboratoire des Sciences du Climat et de l' Environnement, CEA-CNRS, Gif-sur-Yvette (France); Yool, A. [Southampton Oceanography Centre, Southampton (United Kingdom); Plattner, G.K.; Joos, F. [Bern Univ., Bern (Switzerland). Physics Inst.; Maier-Reimer, E. [Max Planck Inst. fuer Meteorologie, Hamburg (Germany); Weirig, M.F.; Schlitzer, R. [Alfred Wegener Inst. for Polar and Marine Research, Bremerhaven (Germany); Caldeira, K.; Wickett, M.E. [Lawrence Livermore National Laboratory, CA (United States); Matear, R.J. [Australian Commonwealth Scientific and Research Organization, Hobart (Australia); Mignone, B.K.; Sarmiento, J.L. [Princeton Univ., Princeton, NJ (United States). AOS Program

    2005-07-01

    Ten ocean general circulation models (OCGMs) were compared as part of an international study investigating the ocean's ability to efficiently sequester carbon dioxide (CO{sub 2}). The models were selected for their ability to simulate radiocarbon and CFC-11. All of the model simulations neglected the influence of marine biota, and the simulations used only dissolved inorganic carbon (DIC) as a tracer in order to conserve computing resources. The models were integrated using standard ocean carbon-cycle model intercomparison project (OCMIP) formulations for gas exchange boundary conditions to obtain pre-industrial conditions. All models used the same predefined atmospheric CO{sub 2} records compiled from 1765 to 2000, as well as future scenarios in which atmospheric CO{sub 2} was stabilized at 650 ppm. Injections occurred over a period of 100 years. Results of the study showed that global budgets for CFC-11 and radiocarbon were correlated with global efficiencies for a 3000 m injection simulation. The 3000 m injection efficiency was then correlated with the global mean for deep natural radiocarbon. Results showed that simultaneously accounting for constraints from both CFC-11 and natural radiocarbon narrowed the range for a 3000 m injection efficiency in the year 2500 by a factor of 4. The study showed that models must be able to simulate global inventories for CFC-11 as well as global means for radiocarbon in deep ocean scenarios in order to be credible. It was concluded that models using both constraints will more accurately simulate global injection efficiencies.

  7. Magnetism switching and band-gap narrowing in Ni-doped PbTiO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Wenliang; Yu, Lu; Yang, Pingxiong, E-mail: pxyang@ee.ecnu.edu.cn; Chu, Junhao [Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering, East China Normal University, Shanghai 200241 (China); Deng, Hongmei [Instrumental Analysis and Research Center, Institute of Materials, Shanghai University, 99 Shangda Road, Shanghai 200444 (China)

    2015-05-21

    Ions doping-driven structural phase transition accompanied by magnetism switching and band-gap narrowing effects has been observed in PbTi{sub 1−x}Ni{sub x}O{sub 3−δ} (xPTNO, x = 0.00, 0.06, and 0.33) thin films. With the increase of x, the xPTNO thin films exhibit not only a phase transition from the pseudotetragonal structure to a centrosymmetric cubic structure but also a drastic decrease of grain size. Moreover, the as-grown Ni-doped PbTiO{sub 3} (PTO) thin films show obvious room-temperature ferromagnetism and an increased saturation magnetization with increasing the Ni content, in contrast to undoped PTO, which shows diamagnetism. A bound magnetic polaron model was proposed to understand the observed ferromagnetic behavior of PTO-derived perovskite thin films. Furthermore, the 0.33PTNO thin film presents a narrowed band-gap, much smaller than that of PTO, which is attributed to new states of both the highest occupied molecular orbital and the lowest unoccupied molecular orbital in an electronic structure with the presence of Ni. These findings may open up a route to explore promising perovskite oxides as candidate materials for use in multiferroics and solar-energy devices.

  8. Influence of a narrow strait connecting a large ocean and a small sea on magnetotelluric data: Gibraltar Strait

    Science.gov (United States)

    González-Castillo, Lourdes; Junge, Andreas; Galindo-Zaldívar, Jesús; Löwer, Alexander

    2015-11-01

    Long period magnetotelluric (LMT) data are generally used as the prime tool to shed light on the conductivity of the deep crust and upper mantle structure. Naturally, LMT data are sensitive to the influence of highly conductive bodies even at far distances. Sea water constitutes the main widespread electrical conductor at shallow levels of the Earth's crust. Its low resistivity values, around 0.25 Ωm, contrast sharply with most geological structures of solid earth. Consequently, the presence of irregular continental borders and varying bathymetries significantly influences LMT parameter, such as phase tensor and tipper vectors. This effect is especially important in areas where large and small oceans are connected by narrow gateways. The Gibraltar Strait (southern Spain) connects the vast Atlantic Ocean with the irregular and relatively small Mediterranean Sea. Several 3D models have been developed in the region nearby the Strait, some featuring a roughly simplified geological structure, to show the influence of seawater on tipper and phase tensor. Here, detailed bathymetry (General Bathymetric Chart of the Oceans, GEBCO) including the coastline is considered in a model that enables us to analyze the influence of the Strait of Gibraltar on LMT data. We stress the significance of the Sea for LMT data interpretation and the development of 3D conductivity models, especially in regions involving complex coastline geometries and bathymetry near narrow straits. Forward modeling studies are essential to accurately appraise the sea influence, which may mask 3D geological structures.

  9. General Formulation for the Calibration and Characterization of Narrow-gap Etalons: the OSIRIS/GTC Tunable Filters Case

    CERN Document Server

    Gonzalez, J J; Gonzalez-Serrano, J I; Sanchez-Portal, M

    2014-01-01

    Tunable filters are a powerful way of implementing narrow-band imaging mode over wide wavelength ranges, without the need of purchasing a large number of narrow-band filters covering all strong emission or absorption lines at any redshift. However, one of its main features is a wavelength variation across the field of view, sometimes termed the phase effect. In this work, an anomalous phase effect is reported and characterized for the OSIRIS instrument at the 10.4m Gran Telescopio Canarias. The transmitted wavelength across the field of view of the instrument depends, not only on the distance to the optical centre, but on wavelength. This effect is calibrated for the red tunable filter of OSIRIS by measuring both normal-incidence light at laboratory and spectral lamps at the telescope at non-normal incidence. This effect can be explained by taking into account the inner coatings of the etalon. In a high spectral resolution etalon, the gap between plates is much larger than the thickness of the inner reflectiv...

  10. High ionic strength narrows the population of sites participating in protein ion-exchange adsorption: a single-molecule study.

    Science.gov (United States)

    Kisley, Lydia; Chen, Jixin; Mansur, Andrea P; Dominguez-Medina, Sergio; Kulla, Eliona; Kang, Marci K; Shuang, Bo; Kourentzi, Katerina; Poongavanam, Mohan-Vivekanandan; Dhamane, Sagar; Willson, Richard C; Landes, Christy F

    2014-05-23

    The retention and elution of proteins in ion-exchange chromatography is routinely controlled by adjusting the mobile phase salt concentration. It has repeatedly been observed, as judged from adsorption isotherms, that the apparent heterogeneity of adsorption is lower at more-eluting, higher ionic strength. Here, we present an investigation into the mechanism of this phenomenon using a single-molecule, super-resolution imaging technique called motion-blur Points Accumulation for Imaging in Nanoscale Topography (mbPAINT). We observed that the number of functional adsorption sites was smaller at high ionic strength and that these sites had reduced desorption kinetic heterogeneity, and thus narrower predicted elution profiles, for the anion-exchange adsorption of α-lactalbumin on an agarose-supported, clustered-charge ligand stationary phase. Explanations for the narrowing of the functional population such as inter-protein interactions and protein or support structural changes were investigated through kinetic analysis, circular dichroism spectroscopy, and microscopy of agarose microbeads, respectively. The results suggest the reduction of heterogeneity is due to both electrostatic screening between the protein and ligand and tuning the steric availability within the agarose support. Overall, we have shown that single molecule spectroscopy can aid in understanding the influence of ionic strength on the population of functional adsorbent sites participating in the ion-exchange chromatographic separation of proteins.

  11. Tunable narrow band source via the strong coupling between optical emitter and nanowire surface plasmons

    CERN Document Server

    Yang, J; Niu, Y P; Qi, Y H; Zhou, F X; Gong, S Q

    2014-01-01

    The spectrum width can be narrowed to a certain degree by decreasing the coupling strength for the two-level emitter coupled to the propagating surface plasmon. But the width can not be narrowed any further because of the loss of the photon out of system by spontaneous emission from the emitter. Here we propose a new scheme to construct a narrow-band source via a one-dimensional waveguide coupling with a three-level emitter. It is shown that the reflective spectrum width can be narrowed avoiding the impact of the loss. This approach opens up the possibility of plasmonic ultranarrow single-photon source.

  12. Image-potential band-gap narrowing at a metal/semiconductor interface

    OpenAIRE

    2001-01-01

    GW approximation is used to systematically revisit the image-potential band-gap narrowing at metal/semiconductor interfaces proposed by Inkson in the 1970's. Here we have questioned how the narrowing as calculated from quasi-particle energy spectra for the jellium/Si interface depends on $r_s$ of the jellium. The gap narrowing is found to only weakly depend on $r_s$ (i.e., narrowing $\\simeq 0.3$ eV even for a large $r_s = 6)$. Hence we can turn to smaller polarizability in the semiconductor s...

  13. Kanata optical and X-ray monitoring of Gamma-ray emitting Narrow-Line Seyfert 1 and Radio galaxies

    CERN Document Server

    Kawaguchi, Kenji; Tanaka, Yasuyuki; Itoh, Ryosuke; Uemura, Makoto; Akitaya, Hiroshi; Kanda, Yuka; Shiki, Kensei; Takaki, Katsutoshi

    2015-01-01

    Broadband spectrum of AGN consists of multiple components such as jet emission and accretion disk emission. Temporal correlation study is useful to understand emission components and their physical origins. We have performed optical monitoring using Kanata telescope for 4 radio galaxies and 6 radio-loud Narrow-Line Seyfert 1 (RL-NLSy1): 2 gamma-ray-loud RL-NLSy1s, 1H 0323+342 and PMN J0948+0022, and 4 gamma-ray-quiet RL-NLSy1s. From these results, it is suggested that RL-NLSy1s show a disk-dominant phase and a jet-dominant phase in the optical band, but it is not well correlated with brightness.

  14. Implementation of IIR ADF for narrow band noise elimination by using of DSP; DSP ni yoru kyotaiiki zatsuon jokyoyo IIR-ADF no jitsugen

    Energy Technology Data Exchange (ETDEWEB)

    Nakanishi, T.; Yamaguchi, E.; Takumi, I.; Hata, M. [Nagoya Institute of Technology, Nagoya (Japan); Nakano, M. [Denso Corp., Nagoya (Japan)

    1997-12-20

    An Adaptive Digital Filter (ADF), which has palarel connected 2nd order IIR filters, for narrow band noise elimination is proposed already. The proposed adaptation algorithm, however, does not take account of delay caused by anti-alias Low-Pass Filter (LPF) and Analogue to Digital (A/D), and Digital to Analogue (D/A) converter. So, in real applications, the ADF implemented with Digital Signal Processor (DSP) shows poor capability of eliminating narrow band noise. In this paper, we propose a method to compensate phase of output signal from ADF. The compensation is accomplished with 1st order FIR filter inserted in the output line of the ADF. We also show how to set the coefficient values of the FIR filter. And, we scrutinize ability to eliminate noise and computational cost through practical implementation of the ADF and the proposed phase compensation filter. 6 refs., 8 figs., 1 tab.

  15. Effects of two-phase flow on the deflagration of porous energetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Margolis, S.B. [Sandia National Labs., Livermore, CA (United States); Williams, F.A. [Univ. of California, San Diego, La Jolla, CA (United States). Dept. of Applied Mechanics and Engineering Sciences

    1994-07-01

    Theoretical analyses are developed for the multi-phase deflagration of porous energetic solids, such as degraded nitramine propellants, that experience significant gas flow in the solid preheat region and are characterized by the presence of exothermic reactions in a bubbling melt layer at their surfaces. Relative motion between the gas and condensed phases is taken into account in both regions, and expressions for the mass burning rate and other quantities of interest, such as temperature and volume-fraction profiles, are derived by activation-energy asymptotics. The model extends recent work by allowing for gas flow in the unburned solid, and by incorporating pressure effects through the gas-phase equation of state. As a consequence, it is demonstrated how most aspects of the deflagration wave, including its structure, propagation speed and final temperature, depend on the local pressure in the two-phase regions.

  16. Multi-tap complex-coefficient incoherent microwave photonic filters based on optical single-sideband modulation and narrow band optical filtering.

    Science.gov (United States)

    Sagues, Mikel; García Olcina, Raimundo; Loayssa, Alayn; Sales, Salvador; Capmany, José

    2008-01-07

    We propose a novel scheme to implement tunable multi-tap complex coefficient filters based on optical single sideband modulation and narrow band optical filtering. A four tap filter is experimentally demonstrated to highlight the enhanced tuning performance provided by complex coefficients. Optical processing is performed by the use of a cascade of four phase-shifted fiber Bragg gratings specifically fabricated for this purpose.

  17. Optogenetic Central Amygdala Stimulation Intensifies and Narrows Motivation for Cocaine.

    Science.gov (United States)

    Warlow, Shelley M; Robinson, Mike J F; Berridge, Kent C

    2017-08-30

    Addiction is often characterized by intense motivation for a drug, which may be narrowly focused at the expense of other rewards. Here, we examined the role of amygdala-related circuitry in the amplification and narrowing of motivation focus for intravenous cocaine. We paired optogenetic channelrhodopsin (ChR2) stimulation in either central nucleus of amygdala (CeA) or basolateral amygdala (BLA) of female rats with one particular nose-poke porthole option for earning cocaine infusions (0.3 mg/kg, i.v.). A second alternative porthole earned identical cocaine but without ChR2 stimulation. Consequently, CeA rats quickly came to pursue their CeA ChR2-paired cocaine option intensely and exclusively, elevating cocaine intake while ignoring their alternative cocaine alone option. By comparison, BLA ChR2 pairing failed to enhance cocaine motivation. CeA rats also emitted consummatory bites toward their laser-paired porthole, suggesting that higher incentive salience made that cue more attractive. A separate progressive ratio test of incentive motivation confirmed that CeA ChR2 amplified rats' motivation, raising their breakpoint effort price for cocaine by 10-fold. However, CeA ChR2 laser on its own lacked any reinforcement value: laser by itself was never self-stimulated, not even by the same rats in which it amplified motivation for cocaine. Conversely, CeA inhibition by muscimol/baclofen microinjections prevented acquisition of cocaine self-administration and laser preference, whereas CeA inhibition by optogenetic halorhodopsin suppressed cocaine intake, indicating that CeA circuitry is needed for ordinary cocaine motivation. We conclude that CeA ChR2 excitation paired with a cocaine option specifically focuses and amplifies motivation to produce intense pursuit and consumption focused on that single target.SIGNIFICANCE STATEMENT In addiction, intense incentive motivation often becomes narrowly focused on a particular drug of abuse. Here we show that pairing central

  18. Pre-recombinational energy release and narrow features in the CMB spectrum

    CERN Document Server

    Chluba, J

    2008-01-01

    Energy release in the early Universe (z~1800) and HeII (z>~7000), and therefore differ from those arising due to normal cosmological recombination in the undisturbed CMB blackbody radiation field. We present the results of numerical computations including 25 atomic shells for both HI and HeII, and discuss the contributions of several individual transitions in detail. As examples, we consider the case of instantaneous energy release (e.g. due to phase transitions) and exponential energy release because of long-lived decaying particles. Our computations show that due to possible pre-recombinational atomic transitions the variability of the CMB spectral distortion increases when comparing with the distortions aris ing in the normal recombination epoch. The existence of these narrow spectral features would open an unique way to separate y-distortions due to pre-recombinational ($1400<~ z <~5x10^4) energy release from those arising in the post-recombinational era at redshifts z<~800. (abridged)

  19. Electrochemical Synthesis of Bismuth Particles: Tuning Particle Shape through Substrate Type within a Narrow Potential Window.

    Science.gov (United States)

    Bilican, Doga; Fornell, Jordina; Sort, Jordi; Pellicer, Eva

    2017-01-06

    Bismuth (Bi) electrodeposition was studied on Si/Ti/Au, FTO-, and ITO-coated glasses from acidic nitrate solutions with and without gluconate within a narrow potential window (ΔE = 80 mV). This potential range was sufficient to observe a change in particle shape, from polyhedrons (including hexagons) to dendrites, the trend being slightly different depending on substrate activity. In all cases, though, the formation of dendrites was favoured as the applied potential was made more negative. Bi particles were more uniformly distributed over the substrate when sodium gluconate was added to the electrolyte. X-ray diffraction analyses of dendrites grown at -0.28 V indicated that they exhibit the rhombohedral phase of Bi and are predominantly oriented along the (003) plane. This orientation is exacerbated at the lowest applied potential (-0.20 V vs. Ag|AgCl) on glass/ITO substrate, for which completed and truncated hexagons are observed from the top view scanning electron microscopy images.

  20. A general analytical solution for groundwater fluctuations due to dual tide in long but narrow islands

    Science.gov (United States)

    Huang, Ching-Sheng; Yeh, Hund-Der; Chang, Chia-Hao

    2012-05-01

    This paper develops a general mathematical model for describing head fluctuations in an aquifer of long but narrow islands subject to a dual tide effect. The upper boundary condition of the aquifer is represented by an equation combining the simplified free surface equation with a leakage term. Such an equation is considered as a general expression representing the upper boundary condition of a confined, unconfined, or leaky confined aquifer. The closed-form solution of the model represented by two series terms is developed by the direct Fourier method and finite Fourier sine transform. One of the series can reduce to a closed-form expression by means of contour integral and residue theorem. If the width of the island is very large, this solution gives the predicted head almost the same as that of the solution for an aquifer subject to a single tide effect. It is found that the presence of an upper aquitard produces significant vertical flow in the lower leaky confined aquifer even if the aquitard permeability is low. Neglecting such vertical flow may result in an overestimate of hydraulic head in the leaky confined aquifer. The attenuation factor and phase lag predicted from the present solution subject to the dual tide effect agree well with those estimated from 57 day head fluctuation data observed at Garden Island, Australia.