Sample records for controlling spontaneous emission

  1. Coherent control of spontaneous emission near a photonic band edge

    Microsoft Academic Search

    Mesfin Woldeyohannes; Sajeev John

    2003-01-01

    We demonstrate the coherent control of spontaneous emission for a three-level atom located within a photonic band gap (PBG) material, with one resonant frequency near the edge of the PBG. Spontaneous emission fro mt he three-level atom can be totally suppressed or strongly enhanced depending on the relative phase between the steady-state control laser coupling the two upper levels and

  2. Spontaneous Emission Control in a Plasmonic Structure

    Microsoft Academic Search

    Hideo Iwase; Yiyang Gong; Dirk Englund; Jelena Vu?kovi?

    \\u000a Surface plasmon polaritons (SPPs) are electromagnetic waves at optical frequencies that propagate at the surface of a conductor\\u000a [1]. SPPs can trap optical photons far below their diffraction limit. The field confinement of SPP provides the environment\\u000a for controlling the interaction between light and matter. In this chapter, we discuss the quantum electrodynamics (QED) of\\u000a SPP coupling of excitons near

  3. Ultrafast non-local control of spontaneous emission.

    PubMed

    Jin, Chao-Yuan; Johne, Robert; Swinkels, Milo Y; Hoang, Thang B; Midolo, Leonardo; van Veldhoven, Peter J; Fiore, Andrea

    2014-11-01

    The radiative interaction of solid-state emitters with cavity fields is the basis of semiconductor microcavity lasers and cavity quantum electrodynamics (CQED) systems. Its control in real time would open new avenues for the generation of non-classical light states, the control of entanglement and the modulation of lasers. However, unlike atomic CQED or circuit quantum electrodynamics, the real-time control of radiative processes has not yet been achieved in semiconductors because of the ultrafast timescales involved. Here we propose an ultrafast non-local moulding of the vacuum field in a coupled-cavity system as an approach to the control of radiative processes and demonstrate the dynamic control of the spontaneous emission (SE) of quantum dots (QDs) in a photonic crystal (PhC) cavity on a ? 200 ps timescale, much faster than their natural SE lifetimes. PMID:25218324

  4. Active magneto-optical control of spontaneous emission in graphene

    E-print Network

    Kort-Kamp, W J M; Bastos, G; Pinheiro, F A; Rosa, F S S; Peres, N M R; Farina, C

    2015-01-01

    We investigate the spontaneous emission rate of a two-level quantum emitter near a graphene-coated substrate under the influence of an external magnetic field. We demonstrate that the application of the magnetic field can substantially increase or decrease the decay rate. We show that a suppression as large as 99$\\%$ in the Purcell factor is achieved even for moderate magnetic fields. The emitter's lifetime is a discontinuous function of $|{\\bf B}|$, which is a direct consequence of the occurrence of discrete Landau levels in graphene. We demonstrate that, in the near-field regime, the magnetic field enables an unprecedented control of the decay pathways into which the photon/polariton can be emitted. Our findings strongly suggest that a magnetic field could act as an efficient agent for on-demand, active control of light-matter interactions in graphene at the quantum level.

  5. Quantum control of population inversion in the presence of spontaneous emission

    E-print Network

    S. G. Schirmer; Andrew D. Greentree; A. I. Solomon

    2001-03-20

    The detrimental effect of spontaneous emission on the performance of control schemes designed to achieve population inversion between the ground state and a highly excited atomic state are studied using computer simulations.

  6. Single Photon Subradiance:Quantum control of spontaneous emission and ultrafast readout

    E-print Network

    Marlan O. Scully

    2015-05-12

    Recent work has shown that collective single photon emission from an ensemble of resonate two-level atoms is a rich field of study. For example single photon superradiance from an extended ensemble yields enhanced directional spontaneous emission; and when the effects of the collective Lamb shift are included it becomes even more interesting. The present paper addresses the flip side of superradiance, i.e., subradiance. Single photon subradiant states are potentially stable against collective spontaneous emission and can have ultrafast readout. In particular, it is shown how many atom collective effects can be used to control emission by preparing and switching between subradiant and superradiant states.

  7. Quantum dot spontaneous emission control in a ridge waveguide

    NASA Astrophysics Data System (ADS)

    Stepanov, Petr; Delga, Adrien; Zang, Xiaorun; Bleuse, Joël; Dupuy, Emmanuel; Peinke, Emanuel; Lalanne, Philippe; Gérard, Jean-Michel; Claudon, Julien

    2015-01-01

    We investigate the spontaneous emission (SE) of self-assembled InAs quantum dots (QDs) embedded in GaAs ridge waveguides that lay on a low index substrate. In thin enough waveguides, the coupling to the fundamental guided mode is vanishingly small. A pronounced anisotropy in the coupling to non-guided modes is then directly evidenced by normal-incidence photoluminescence polarization measurements. In this regime, a measurement of the QD decay rate reveals a SE inhibition by a factor up to 4. In larger wires, which ensure an optimal transverse confinement of the fundamental guided mode, the decay rate approaches the bulk value. Building on the good agreement with theoretical predictions, we infer from calculations the fraction ? of SE coupled to the fundamental guided mode for some important QD excitonic complexes. For a charged exciton (isotropic in plane optical dipole), ? reaches 0.61 at maximum for an on-axis QD. In the case of a purely transverse linear optical dipole, ? increases up to 0.91. This optimal configuration is achievable through the selective excitation of one of the bright neutral excitons.

  8. Spontaneous emission control of single quantum dots in bottom-up nanowire waveguides

    NASA Astrophysics Data System (ADS)

    Bulgarini, Gabriele; Reimer, Michael E.; Zehender, Tilman; Hocevar, Moïra; Bakkers, Erik P. A. M.; Kouwenhoven, Leo P.; Zwiller, Valery

    2012-03-01

    Nanowire waveguides with controlled shape are promising for engineering the collection efficiency of quantum light sources. We investigate the exciton lifetime in individual InAsP quantum dots, perfectly positioned on-axis of InP nanowire waveguides. We demonstrate control over the quantum dot spontaneous emission by varying the nanowire diameter in e-beam patterned arrays, which modifies the coupling efficiency of the emitter to the fundamental waveguide mode. The spontaneous emission rate is inhibited by a factor of 12 in thin nanowires compared to nanowires with optimized waveguide diameter. From the measured inhibition factor, we determine a high radiative yield exceeding 92% in bottom-up grown nanowires.

  9. Spontaneous Emission Control with Planar Dielectric Structures: An Asset for Ultrasensitive Fluorescence Analysis

    Microsoft Academic Search

    Cédric Begon; Hervé Rigneault; Per Jonsson; John G. Rarity

    2000-01-01

    We report on the interest of spontaneous emission control with planar dielectric multi-layer structures to increase the fluorescence collection efficiency in single-molecule detection experiments and ultrasensitive analysis. The effect of a very simple Fabry Perot microcavity on the radiation pattern of Eu 3+ chelate molecules is introduced and discussed. Then the fluorescence correlation spectroscopy (FCS) technique is used to detect

  10. Two-Dimensional Atom Localization via Controlled Spontaneous Emission in a Coupled Cavity Waveguide

    NASA Astrophysics Data System (ADS)

    Liu, Ronggang

    2015-01-01

    A scheme of atom localization based on controlled spontaneous emission is proposed, in which the atom is embedded in a coupled cavity waveguide with two orthogonal standing-wave fields. We can achieve high-precision and high-resolution atom localization by properly adjusting the system parameters. It is shown that the localization is significantly improved due to the strong coupling effect between the atom and a coupled cavity waveguide.

  11. Controlling spontaneous emission in photonic-band-gap materials doped with nanoparticles

    SciTech Connect

    Singh, Mahi R. [Department of Physics and Astronomy, University of Western Ontario, London N6A 3K7 (Canada)

    2007-03-15

    The phenomenon of spontaneous emission cancellation has been investigated in photonic-band-gap materials in the presence of dipole-dipole interaction. The material is densely doped with an ensemble of five-level nanoparticles. The mean field theory is used to calculate the effect of the dipole-dipole interaction whereas the linear response theory is used to calculate the expressions for the real and imaginary susceptibilities. Numerical simulations are performed for an isotropic photonic-band-gap material. Interesting results are predicted such as the control of the spontaneous emission cancellation by moving the resonance energies between the energy band and energy gap. It is also found that the photonic-band-gap material can be switched between absorptive and nonabsorptive states by changing the strength of the dipole-dipole interaction and the resonance energies in the energy band.

  12. Quantum state-controlled directional spontaneous emission of photons into a nanophotonic waveguide

    PubMed Central

    Mitsch, R.; Sayrin, C.; Albrecht, B.; Schneeweiss, P.; Rauschenbeutel, A.

    2014-01-01

    The spin of light in subwavelength-diameter waveguides can be orthogonal to the propagation direction of the photons because of the strong transverse confinement. This transverse spin changes sign when the direction of propagation is reversed. Using this effect, we demonstrate the directional spontaneous emission of photons by laser-trapped caesium atoms into an optical nanofibre and control their propagation direction by the excited state of the atomic emitters. In particular, we tune the spontaneous emission into the counter-propagating guided modes from symmetric to strongly asymmetric, where more than % of the optical power is launched into one or the other direction. We expect our results to have important implications for research in quantum nanophotonics and for implementations of integrated optical signal processing in the quantum regime. PMID:25502565

  13. X-ray Spontaneous Emission Control By 1D-PBG Structure

    SciTech Connect

    Andre, Jean-Michel; Jonnard, Philippe [Laboratoire de Chimie Physique-Matiere et Rayonnement, CNRS, Universite Paris 6, UMR 7614, 11 rue Pierre et Marie Curie, F-75231 Paris CEDEX 05 (France)

    2010-04-06

    The control of the decay rate of an excited atom through the photonic mode density (PMD) was pointed out at radiofrequency by Purcell in 1946. Nowadays the development of sophisticated photonic band structures makes it possible to monitor the PMD at shorter radiation wavelengths and then to manipulate the spontaneous emission of atoms in the hard region of the electromagnetic spectrum especially in the visible domain. In this communication we study the possibility of monitoring the x-ray emission by means of one-dimensional photonic band structures such as periodic multilayer systems. Enhancement or inhibition of soft x-ray emissions seems now to be feasible by means of the state-of-the art in x-ray optics.

  14. Controlled spontaneous emission of single molecules in a two-dimensional photonic band gap.

    PubMed

    Kaji, Takahiro; Yamada, Toshiki; Ito, Syoji; Miyasaka, Hiroshi; Ueda, Rieko; Inoue, Shin-ichiro; Otomo, Akira

    2013-01-01

    We have established a new platform to control the rate of spontaneous emission (SE) of organic molecules in the visible-light region using a combination of a two-dimensional (2D) photonic crystal (PC) slab made of TiO(2) and a single-molecule measurement method. The SE from single molecules of a perylenediimide derivative was effectively inhibited via a radiation field controlled by the 2D PC slab, which has a photonic band gap (PBG) for transverse-electric (TE)-polarized light. The fluorescence lifetimes of the single molecules were extended up to 5.5 times (28.6 ns) by the PBG effect. This result appears to be the first demonstration of drastic lifetime elongation for single molecules due to a PBG effect. PMID:23253079

  15. Coherent control of collective spontaneous emission in an extended atomic ensemble and quantum storage

    SciTech Connect

    Kalachev, Alexey; Kroell, Stefan [Zavoisky Physical-Technical Institute of the Russian Academy of Sciences, Sibirsky Trakt 10/7, Kazan, 420029 (Russian Federation); Department of Physics, Lund Institute of Technology (LTH), Box 118, S-221 00 Lund (Sweden)

    2006-08-15

    Coherent control of collective spontaneous emission in an extended atomic ensemble resonantly interacting with single-photon wave packets is analyzed. A scheme for coherent manipulation of collective atomic states is developed such that superradiant states of the atomic system can be converted into subradiant ones and vice versa. Possible applications of such a scheme for optical quantum-state storage and single-photon wave packet shaping are discussed. It is shown that also in the absence of inhomogeneous broadening of the resonant line, single-photon wave packets with arbitrary pulse shape may be recorded as a subradiant state and reconstructed even although the duration of the wave packets is larger than the superradiant lifetime. Specifically the applicability for storing time-bin qubits, which are used in quantum cryptography, is analyzed.

  16. Controlling spontaneous emission of a two-level atom by hyperbolic metamaterials

    E-print Network

    Zheng Liu; Wei Li; Xunya Jiang

    2012-03-03

    Within the frame of quantum optics we analyze the properties of spontaneous emission of two-level atom in media with indefinite permittivity tensor where the geometry of the dispersion relation is characterized by an ellipsoid or a hyperboloid(hyperbolic medium). The decay rate is explicitly given with the orientation of the dipole transition matrix element taken into account. It indicates that for the ellipsoid case the intensity of the photons coupled into different modes can be tuned by changing the direction of the matrix element and for the hyperboloid case it is found that spontaneous emission in hyperbolic medium can be dramatically enhanced compared to the dielectric background. Moreover, spontaneous emission exhibit the strong directivity and get the maximum in the asymptote direction.

  17. Spontaneous Emission from Planar Microstructures

    Microsoft Academic Search

    D. G. Deppe; C. Lei; C. C. Lin; D. L. Huffaker

    1994-01-01

    The alteration of spontaneous emission characteristics in terms of the spontaneous lifetime and spectral emission characteristics are discussed for dipoles in the presence of nearby planar reflecting interfaces and cavities, specifically for the case of semiconductors. For dipoles closely spaced to absorbing metal mirrors, significant lifetime change is possible. Analysis and experimental data are presented for light emitting diodes. For

  18. Silicon photonic crystals spontaneous emission

    E-print Network

    Polman, Albert

    Silicon photonic crystals and spontaneous emission #12;Silicon photonic crystals and spontaneous and Molecular Physics, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands. #12;Silicon photonic crystals based on silicon 17 2.1 Introduction 18 2.2 Bandstructure calculations 18 2.3 2-D photonic crystal

  19. Modification and control of the spontaneous emission from an M-type atom embedded in an anisotropic photonic crystal

    NASA Astrophysics Data System (ADS)

    Ding, Chunling; Li, Jiahua; Yang, Xiaoxue; Lü, Xin-You

    2011-05-01

    We describe the spontaneous emission properties of an M-type five-level atom embedded in a photonic crystal (PC), which is coherently driven by two external laser fields. It leads to two types of quantum interference: reservoir-induced interference and laser-induced interference. Considering different detunings of atomic transition frequencies from band edges, we reveal some interesting phenomena such as spectral-line enhancement, spectral-line suppression, spectral-line narrowing, reservoir-induced cancellation of spontaneous emission and the appearance of dark lines, which originate from the quantum interference effects and the control of external laser fields. These investigations suggest possible applications in quantum optics, optical communications and in the fabrication of novel optoelectronic devices.

  20. Time-dependent inhibited spontaneous emission

    Microsoft Academic Search

    D. Branning; Y. H. Shin; S. Khanal; A. L. Migdall

    2011-01-01

    The spontaneous emission rate of photon pairs in a parametric downconverter can be inhibited by a cavity mirror. Using a fast switch, we detect photons within the cavity during times when the emission was inhibited. In the process of inhibited spontaneous emission, an excited atom is prevented from spontaneously emitting radiation by a reflecting cavity that surrounds it. Quantum theory

  1. Inhibited spontaneous emission in solid-state physics and electronics

    Microsoft Academic Search

    Eli Yablonovitch

    1987-01-01

    It has been recognized for some time that the spontaneous emission by atoms is not necessarily a fixed and immutable property of the coupling between matter and space, but that it can be controlled by modification of the properties of the radiation field. This is equally true in the solid state, where spontaneous emission plays a fundamental role in limiting

  2. Quenching of spontaneous emission coefficients in plasmas

    SciTech Connect

    Chung, Y.; Lemaire, P.; Suckewer, S.

    1987-09-01

    We have observed changing Einstein coefficients of spontaneous emission as a function of electron density in CO/sub 2/ laser-produced plasmas. These measurements are based on the intensity branching ratio of CIV lines 5801 to 5812 A and 312.41 to 312.46 A which share a common upper level. Similar observations for CIII lines are also discussed. 12 refs., 3 figs.

  3. Modified spontaneous emission in nanophotonic structures

    NASA Astrophysics Data System (ADS)

    Pelton, Matthew

    2015-07-01

    Spontaneous emission is not an inherent property of a luminescent material; rather, it arises due to interaction between the material and its local electromagnetic environment. Changing the environment can thus alter the emission rate, with potential applications in sensing, integrated photonics and solar energy conversion. Significant increases in emission rate require an optical resonator that stores light in as small a volume as possible, for as long as possible. This is currently achieved using two main systems: photonic crystal microcavities and plasmonic metal nanoparticles. These two systems have largely been developed independently, but the underlying physical mechanisms are the same. Comparing the two provides insight into emission modification and illustrates some of the subtleties involved in interpreting experimental results.

  4. Nuclear-spin noise and spontaneous emission

    NASA Astrophysics Data System (ADS)

    Sleator, Tycho; Hahn, Erwin L.; Hilbert, Claude; Clarke, John

    1987-08-01

    The spontaneous emission from nuclear spins has been observed at liquid-4He temperatures. The spins, 35Cl nuclei, are placed in the inductor of a tuned LCR circuit coupled to a dc superconducting quantum interference device used as a radio-frequency amplifier. When the spins are saturated and have zero polarization, the emission is observed at the nuclear quadrupole Larmor frequency as a bump in the spectral density of the Nyquist noise current in the tuned circuit. This bump arises from the temperature-independent fluctuations in the transverse component of the nuclear magnetization. When the spins are in thermal equilibrium, on the other hand, a dip in the spectral density of the current noise is observed, arising from an induced absorption of noise power from the circuit at the Larmor frequency. The standard circuit-coupled Bloch's equation, modified to take into account radiation damping and transverse spin fluctuations, is consistent with the predictions of the Nyquist theorem and the Einstein equation for spontaneous emission. A spin-pendulum model for spin noise is described. The signal-to-noise ratio obtainable in a spin-noise measurement is discussed.

  5. On spontaneous photon emission in collapse models

    NASA Astrophysics Data System (ADS)

    Adler, Stephen L.; Bassi, Angelo; Donadi, Sandro

    2013-06-01

    We reanalyze the problem of spontaneous photon emission in collapse models. We show that the extra term found by Bassi and Dürr is present for non-white (colored) noise, but its coefficient is proportional to the zero frequency Fourier component of the noise. This leads one to suspect that the extra term is an artifact. When the calculation is repeated with the final electron in a wave packet and with the noise confined to a bounded region, the extra term vanishes in the limit of continuum state normalization. The result obtained by Fu and by Adler and Ramazano?lu from application of the Golden Rule is then recovered.

  6. Spontaneous emission from free electron lasers

    SciTech Connect

    Schmitt, M.J.

    1991-01-01

    Characteristics of the fundamental and harmonic emission from free-electron lasers (FELs) is examined in the spontaneous emission regime. The radiation at both odd and even harmonic frequencies is treated for electron beams with finite emittance and energy spread. For wigglers with many wiggle periods, calculation of the SE by integrating an ensemble of electrons along their exact trajectories becomes exceedingly cumbersome. Therefore, a different technique is used in which the far-field radiation pattern of a single electron is manipulated in transform space to include the effects if emittance. The effects of energy spread can be included by weighted sum over the energy distribution. The program execution time for wigglers of arbitrary length is negligible. The transverse radiation patterns including the transverse frequency dependences, are given. How this radiation is modeled in FEL simulation codes is discussed. 8 refs., 5 figs.

  7. Spontaneous emission from accelerated Bloch electrons -- Bloch oscillation radiation

    Microsoft Academic Search

    Valeriy Sokolov; Gerald Iafrate; Joseph Krieger

    2006-01-01

    A theory of spontaneous emission of radiation for a Bloch electron traversing a single band in an external electric field is presented. The radiation field is described by a free space quantized electromagnetic field in the Coulomb gauge. It is shown that the spontaneous emission occurs with frequencies equal to integral multiples of the Bloch frequency without any ad hoc

  8. Enhancement and suppression of spontaneous emission and light scattering by quantum degeneracy

    E-print Network

    Enhancement and suppression of spontaneous emission and light scattering by quantum degeneracy Quantum degeneracy modifies light scattering and spontaneous emission. For fermions, Pauli blocking leads spontaneous emission to be enhanced, while light scattering is suppressed [1]. This difference is attributed

  9. Controlling spontaneous-emission noise in measurement-based feedback cooling of a Bose-Einstein condensate

    NASA Astrophysics Data System (ADS)

    Hush, M. R.; Szigeti, S. S.; Carvalho, A. R. R.; Hope, J. J.

    2013-11-01

    Off-resonant optical imaging is a popular method for continuous monitoring of a Bose-Einstein condensate. However, the disturbance caused by scattered photons places a serious limitation on the lifetime of such continuously monitored condensates. In this paper, we demonstrate that a new choice of feedback control can overcome the heating effects of the measurement backaction. In particular, we show that the measurement backaction caused by off-resonant optical imaging is a multi-mode quantum-field effect, as the entire heating process is not seen in single-particle or mean-field models of the system. Simulating such continuously monitored systems is possible with the number-phase Wigner particle filter, which currently gives both the highest precision and largest timescale simulations amongst competing methods. It is a hybrid between the leading techniques for simulating non-equilibrium dynamics in condensates and particle filters for simulating high-dimensional non-Gaussian filters in the field of engineering. The new control scheme will enable long-term continuous measurement and feedback on one of the leading platforms for precision measurement and the simulation of quantum fields, allowing for the possibility of single-shot experiments, adaptive measurements and robust state-preparation and manipulation.

  10. Characterization of semiconductor lasers by spontaneous emission measurements

    Microsoft Academic Search

    F. Girardin; Guang-Hua Duan

    1997-01-01

    The measurement of spontaneous emission is a powerful characterization technique of semiconductor lasers, which has been developed with the fabrication of the first lasers. It allows the determination of both material and structural parameters such as gain, refractive index, longitudinal effects, etc. Significant advance has been made recently on the understanding of material properties and lasing characteristics by using spontaneous

  11. Temporal and transverse coherence of self-amplified spontaneous emission

    SciTech Connect

    Kim, K.J.

    1997-06-01

    The authors review the coherence properties of the self-amplified spontaneous emission (SASE). Temporally, SASE is similar to the spontaneous undulator radiation except that the spectral bandwidth is about ten times narrower compared with typical undulator radiation. The situation is quite different in the transverse dimension, where SASE is fully coherent.

  12. Inhibited Spontaneous Emission in a Time-Dependent Cavity

    Microsoft Academic Search

    David Branning

    2010-01-01

    In the process of inhibited spontaneous emission, an excited atom is prevented from spontaneously emitting radiation by a reflecting cavity that surrounds it. Quantum theory predicts that, when an atom is first placed into the cavity, it initially radiates at the free-space rate, and the interference from the returning radiation halts any further evolution of the atom into the ground

  13. Effects of local fields on spontaneous emission in dielectric media

    PubMed

    Crenshaw; Bowden

    2000-08-28

    The local-field renormalization of the spontaneous emission rate in a dielectric is explicitly obtained from a fully microscopic quantum-electrodynamical, many-body derivation of Langevin-Bloch operator equations for two-level atoms embedded in an absorptive and dispersive, linear dielectric host. We find that the dielectric local-field enhancement of the spontaneous emission rate is smaller than indicated by previous studies. PMID:10970630

  14. Localized plasmon-engineered spontaneous emission of CdSe/ZnS nanocrystals

    E-print Network

    Demir, Hilmi Volkan

    Localized plasmon-engineered spontaneous emission of CdSe/ZnS nanocrystals closely linewidth of proximal CdSe/ZnS core-shell quantum dots is reduced by 22% and their peak emission wavelength.6 and 15.1 times compared to the control groups of CdSe/ZnS nanocrystals with identical nano

  15. Enhancing spontaneous emission rates of molecules using nanopatterned multilayer

    E-print Network

    Wang, Deli

    in free space, their spontaneous radiative emission rate is generally enhanced7­9 . Such enhancement artificial material with hyperbolic dispersion relations--the Purcell factor and the radiative power have emitters release their energy predominantly via three channels: radiative emission, plasmonic modes

  16. The properties of amplified spontaneous emission noise in saturated fiber Raman amplifiers operating with CW signals

    E-print Network

    Eisenstein, Gadi

    The properties of amplified spontaneous emission noise in saturated fiber Raman amplifiers emission (ASE) noise in forward and backward pumped saturated Raman amplifiers operating with CW signals: Fiber Raman amplifier; Amplified spontaneous emission noise; Saturation 1. Introduction The noise

  17. Reversible Modulation of Spontaneous Emission by Strain in Silicon Nanowires

    PubMed Central

    Shiri, Daryoush; Verma, Amit; Selvakumar, C. R.; Anantram, M. P.

    2012-01-01

    We computationally study the effect of uniaxial strain in modulating the spontaneous emission of photons in silicon nanowires. Our main finding is that a one to two orders of magnitude change in spontaneous emission time occurs due to two distinct mechanisms: (A) Change in wave function symmetry, where within the direct bandgap regime, strain changes the symmetry of wave functions, which in turn leads to a large change of optical dipole matrix element. (B) Direct to indirect bandgap transition which makes the spontaneous photon emission to be of a slow second order process mediated by phonons. This feature uniquely occurs in silicon nanowires while in bulk silicon there is no change of optical properties under any reasonable amount of strain. These results promise new applications of silicon nanowires as optoelectronic devices including a mechanism for lasing. Our results are verifiable using existing experimental techniques of applying strain to nanowires. PMID:22708056

  18. Photoluminescence and spontaneous emission enhancement in metamaterial nanostructures

    NASA Astrophysics Data System (ADS)

    Singh, M. R.; Cox, J. D.; Brzozowski, M.

    2014-02-01

    We present a theory for the photoluminescence (PL) and spontaneous emission of semiconductor nanoparticles (quantum dots—QDS) doped in a metamaterial heterostructure. The heterostructure is formed by fabricating a split-ring resonator and metallic rod metamaterial on a dielectric substrate. QDs are doped near the interface in the heterostructure. Our results indicate that the PL and spontaneous emission of the QDs are enhanced in the presence of the metamaterial when the exciton and surface plasmon frequencies are resonant. These findings are consistent with recent experimental studies. The present study can be used to make new types of nanoscale optical devices for sensing, switching and imaging applications based on metamaterials.

  19. QED (quantum-electrodynamical) theory of excess spontaneous emission noise

    SciTech Connect

    Milonni, P.W.

    1990-01-01

    The results of a quantum-electrodynamical theory of excess spontaneous emission noise in lossy resonators will be presented. The Petermann K factor'' does not enter into the spontaneous emission rate of a single atom in the cavity. The QED theory allows different interpretations of the K factor, and we use this fact to justify semiclassical analyses and to provide in one example a simple derivation of K in terms of the amplification of the quantum vacuum field entering the resonator through its mirrors. 17 refs.

  20. Structural chaos in reversible spontaneous emission of moving atoms

    SciTech Connect

    Prants, Sergei V; Yusupov, V I [V.I. Il'ichev Pacific Oceanological Institute, Far-Eastern Division of the Russian Academy of Sciences, Vladivostok (Russian Federation)

    2000-07-31

    t is proved analytically and numerically that, under certain conditions, the reversible spontaneous emission of two-level atoms moving in a high-Q resonator and described quantum-classically can be chaotic in the sense of the exponential sensitivity with respect to the initial conditions. The wavelet analysis of the vacuum Rabi oscillations showed that this chaos is structural. The numerical estimates showed that a Rydberg atom maser with a superconducting microwave resonator operating in a strong coupling mode is a promising device for detecting mani-festations of the dynamic chaos in the reversible spontaneous emission. (laser applications and other topics in quantum electronics)

  1. ATOMIC AND MOLECULAR PHYSICS: Spontaneous Emission of a Polarized Atom in a Medium Between Two Parallel Mirrors

    NASA Astrophysics Data System (ADS)

    Wang, De-Hua; Huang, Kai-Yun; Xu, Qiang

    2010-01-01

    Using the photon closed orbit theory, the spontaneous emission rate of a polarized atom in a medium between two parallel mirrors is derived and calculated. It is found that the spontaneous emission rate of a polarized atom between the mirrors is related to the atomic position and the polarization direction. The results show that in the vicinity of the mirror, the variation of the spontaneous emission rate depends crucially on the atomic polarization direction. With the increase of the polarization angle, the oscillation in the spontaneous emission rate becomes decreased. For the polarization direction parallel to the mirror plane, the oscillation is the greatest; while for the perpendicular polarization direction, the oscillation is nearly vanished. The agreement between our result and the quantum electrodynamics result suggests the correctness of our calculation. This study further verifies that the atomic spontaneous emission process can be effectively controlled by changing the polarization orientation of the atom.

  2. Fast physical random number generator using amplified spontaneous emission

    E-print Network

    Murphy, Thomas E.

    . Abshire, "Compact floating-gate true random number generator," Electron. Lett. 42, 1346 ­1347 (2006). 6. CFast physical random number generator using amplified spontaneous emission Caitlin R. S. Williams,1 `good' random number generators," Phys. Rev. Lett. 69, 3382­3384 (1992). 2. M. Isida and H. Ikeda

  3. Amplified spontaneous emission in pulse-pumped Raman amplifiers

    Microsoft Academic Search

    Jake Bromage; P. J. Winzer; L. E. Nelson; M. D. Mermelstein; C. Horn; C. H. Headley

    2003-01-01

    We discuss amplified spontaneous emission (ASE) generated in Raman amplifiers that are counter-pumped with trains of pulses. Our experimental and theoretical results show that if the peak power of the pump pulses is too high, the ASE output from the amplifier can be significantly higher than that from a continuous-wave pumped amplifier providing the same gain. This effect places a

  4. Amplified spontaneous emission in solar-pumped iodine laser

    NASA Technical Reports Server (NTRS)

    Cho, Yong S.; Hwang, In H.; Han, Kwang S.; Lee, Ja H.

    1992-01-01

    The amplified spontaneous emission (ASE) from a long pulse, solar-simulating radiation pumped iodine laser amplifier is studied. The ASE threshold pump intensity is almost proportional to the inverse of the laser gain length when the gas pressure is constant in the laser tube.

  5. Optical gain, spontaneous and stimulated emission of surface plasmon

    E-print Network

    Grandidier, Jonathan

    Optical gain, spontaneous and stimulated emission of surface plasmon polaritons in confined finally apply this formalism to describe gain­assisted propagation in a dielectric­loaded surface plasmon polariton waveguide. © 2010 Optical Society of America OCIS codes: (240.6680) Surface plasmons; (230

  6. Dynamics of Relaxation Processes of Spontaneous Otoacoustic Emissions

    Microsoft Academic Search

    William James Murphy

    1992-01-01

    The dynamical response of spontaneous otoacoustic emissions (SOAEs) to suppression by ipsilateral pulsed external tones of different frequencies and levels is investigated in nine female subjects under normal conditions and in four female subjects during periods when aspirin is being administered. A simple Van der Pol limit-cycle oscillator driven by an external tone is used as an interpretive model. Typical

  7. Effective suppression of amplified spontaneous emission by stimulated Brillouin scattering phase conjugation

    NASA Astrophysics Data System (ADS)

    Ni, C. K.; Kung, A. H.

    1996-10-01

    Backward stimulated Brillouin scattering was used to control the growth of amplified spontaneous emission (ASE), reducing the unwanted emission in a pulse-amplified cw Ti:sapphire laser system from 22% to less than 1 \\times 10-4 in the final output. Suppression of ASE substantially improved the spectral quality of the laser and broadened the range over which the laser is useful. The output duration was compressed, but the pulse remained nearly transform limited.

  8. "OPERA superluminal neutrinos explained by spontaneous emission and stimulated absorption"

    E-print Network

    Rafael Torrealba

    2011-12-05

    In this work it is shown, that for short 3ns neutrino pulses reported by OPERA, a relativistic shape deforming effect of the neutrino distribution function due to spontaneous emission, produces an earlier arrival of 65.8ns in agreement with the reported 62.1ns\\pm 3.7ns, with a RMS of 16.4ns explaining the apparent superluminal effect. It is also shown, that early arrival of long 10500ns neutrinos pulse to Gran Sasso, by 57.8ns with respect to the speed of light, could be explained by a shape deforming effect due to a combination of stimulated absorption and spontaneous emission, while traveling by the decay tunnel that acts as a LASER tube.

  9. Spontaneous emission in one-dimensional photonic crystal lasers

    Microsoft Academic Search

    Anna Tyszka-Zawadzka; Marcin Koba; Pawel Szczepanski

    In this paper, we present an analysis of the spontaneous emission noise in one-dimensional photonic crystal (1D PC) laser. We use semi analytical approach based on stationary solution of the Fokker-Planck equation. Drift and diffusion coefficients, which are necessary to formulate the Fokker-Planck equation, are received from the set of Langevin equations. We derive the exact analytic expressions relating mean

  10. Interference-induced splitting of resonances in spontaneous emission

    E-print Network

    R. Arun

    2007-10-06

    We study the resonance fluorescence from a coherently driven four-level atom in the Y-type configuration. The effects of quantum interference induced by spontaneous emission on the fluorescence properties of the atom are investigated. It is found that the quantum interference resulting from cascade emission decays of the atom leads to a splitting of resonances in the excited level populations calculated as a function of light detuning. For some parameters, interference assisted enhancement of inner sidebands and narrowing of central peaks may also occur in the fluorescence spectrum. We present a physical understandingof our numerical results using the dressed state description of the atom-light interaction.

  11. 2-.mu.m fiber amplified spontaneous emission (ASE) source

    NASA Technical Reports Server (NTRS)

    Jiang, Shibin (Inventor); Wu, Jianfeng (Inventor); Geng, Jihong (Inventor)

    2007-01-01

    A 2-.mu.m fiber Amplified Spontaneous Emission (ASE) source provides a wide emission bandwidth and improved spectral stability/purity for a given output power. The fiber ASE source is formed from a heavy metal oxide multicomponent glass selected from germanate, tellurite and bismuth oxides and doped with high concentrations, 0.5-15 wt. %, thulium oxides (Tm.sub.2O.sub.3) or 0.1-5 wt% holmium oxides (Ho.sub.2O.sub.3) or mixtures thereof. The high concentration of thulium dopants provide highly efficient pump absorption and high quantum efficiency. Co-doping of Tm and Ho can broaden the ASE spectrum.

  12. Inhibited Spontaneous Emission in a Time-Dependent Cavity

    NASA Astrophysics Data System (ADS)

    Branning, David

    2010-03-01

    In the process of inhibited spontaneous emission, an excited atom is prevented from spontaneously emitting radiation by a reflecting cavity that surrounds it. Quantum theory predicts that, when an atom is first placed into the cavity, it initially radiates at the free-space rate, and the interference from the returning radiation halts any further evolution of the atom into the ground state. To observe this initial radiation directly, a wall of the cavity must be quickly replaced with a photon-counting detector, but the femtosecond time scales involved make this observation impossible for atoms. Intsead, our experiment uses spontaneous parametric downconversion, a process in which a single ultraviolet photon from a laser is spontaneously converted into two lower-frequency photons in a nonlinear optical medium. The downconversion is inhibited using a mirror, at much greater distances than is possible for atoms, and the mirror is then ``replaced'' by a detector on a timescale of several nanoseconds using a Pockels cell as a switch. At the detector, the arrival time of the photons indicates whether or not they had existed in the cavity before the switch was activated.

  13. Continuous-variable entanglement in a correlated spontaneous emission laser

    E-print Network

    Tan, HT; Zhu, S. Y.; Zubairy, M. Suhail

    2005-01-01

    Continuous-variable entanglement in a correlated spontaneous emission laser Hua-Tang Tan,1,2 Shi-Yao Zhu,1 and M. Suhail Zubairy3 1Department of Physics, Hong Kong Baptist University, Hong Kong, China 2Department of Physics, Huazhong Normal... University, Wuhan, China 3Institute for Quantum Studies and Department of Physics, Texas A&M University, Texas 77843-4242, USA #1;Received 17 January 2005; revised manuscript received 3 May 2005; published 8 August 2005#2; We discuss the generation...

  14. Continuous-variable entanglement in a correlated spontaneous emission laser 

    E-print Network

    Tan, HT; Zhu, S. Y.; Zubairy, M. Suhail

    2005-01-01

    Continuous-variable entanglement in a correlated spontaneous emission laser Hua-Tang Tan,1,2 Shi-Yao Zhu,1 and M. Suhail Zubairy3 1Department of Physics, Hong Kong Baptist University, Hong Kong, China 2Department of Physics, Huazhong Normal... University, Wuhan, China 3Institute for Quantum Studies and Department of Physics, Texas A&M University, Texas 77843-4242, USA #1;Received 17 January 2005; revised manuscript received 3 May 2005; published 8 August 2005#2; We discuss the generation...

  15. Computation of spontaneous emission dynamics in colored vacua

    E-print Network

    Mohammad Hosain Teimourpour; Ramy El-Ganainy

    2014-12-25

    We present an efficient time domain numerical scheme for computing spontaneous emission dynamics in colored vacua. Starting from first principles, we map the unitary evolution of a dressed two-level quantum emitter onto the problem of electromagnetic radiation from a complex harmonic oscillator under self-interaction conditions. This latter oscillator-field system can be efficiently integrated by using finite difference time domain method without the need for calculating the photonic eigenmodes of the surrounding environment. In contrast to earlier investigations, our computational framework provides a unified numerical treatment for both weak and strong coupling regimes alike. We illustrate the versatility of our scheme by considering several different examples.

  16. Amplified Spontaneous Emission Properties of Semiconducting Organic Materials

    PubMed Central

    Calzado, Eva M.; Boj, Pedro G.; Díaz-García, María A.

    2010-01-01

    This paper aims to review the recent advances achieved in the field of organic solid-state lasers with respect to the usage of semiconducting organic molecules and oligomers in the form of thin films as active laser media. We mainly focus on the work performed in the last few years by our research group. The amplified spontaneous emission (ASE) properties, by optical pump, of various types of molecules doped into polystyrene films in waveguide configuration, are described. The various systems investigated include N,N?-bis(3-methylphenyl)-N,N?-diphenylbenzidine (TPD), several perilenediimide derivatives (PDIs), as well as two oligo-phenylenevinylene derivatives. The ASE characteristics, i.e., threshold, emission wavelength, linewidth, and photostability are compared with that of other molecular materials investigated in the literature. PMID:20640167

  17. TRASER - Total Reflection Amplification of Spontaneous Emission of Radiation

    PubMed Central

    Zachary, Christopher B.; Gustavsson, Morgan

    2012-01-01

    Background and Objective Light and lasers in medical therapy have made dramatic strides since their invention five decades ago. However, the manufacture of lasers can be complex and expensive which often makes treatments limited and costly. Further, no single laser will provide the correct parameters to treat all things. Hence, laser specialists often need multiple devices to practice their specialty. A new concept is described herein that has the potential to replace many lasers and light sources with a single ‘tunable’ device. Study Design/Material and Methods This device amplifies spontaneous emission of radiation by capturing and retaining photons through total internal reflection, hence the acronym Total Reflection Amplification of Spontaneous Emission of Radiation, or TRASER. Results Specific peaks of light can be produced in a reproducible manner with high peak powers of variable pulse durations, a large spot size, and high repetition rate. Conclusion Considering the characteristics and parameters of Traser technology, it is possible that this one device would likely be able to replace the pulsed dye laser and many other light based systems. PMID:22558261

  18. Spontaneous Muon Emission during Fission, a New Nuclear Radioactivity

    E-print Network

    D. B. Ion; M. L. D. Ion; Reveica Ion-Mihai

    2011-01-24

    In this paper the essential theoretical predictions for the nuclear muonic radioactivity are presented by using a special fission-like model similar with that used in description of the pionic emission during fission. Hence, a fission-like model for the muonic radioactivity takes into account the essential degree of freedom of the system: muon-fissility, muon-fission barrier height, etc. Using this model it was shown that most of the SHE-nuclei lie in the region where the muonic fissility parameters attain their limiting value X=1. Hence, the SHE-region is characterized by the absence of a classical barrier toward spontaneous muon and pion emissions. Numerical estimations on the yields for the natural muonic radioactivities of the transuranium elements as well numerical values for barrier heights are given only for even-even parent nuclei. Some experimental results from LCP-identification emission spectrum are reviewed. Also, the experimental results obtained by Khryachkov et al, using new spectrometer for investigation of ternary nuclear fission, are presented. The OPERA-experiment proposed to perform search for muonic radioactivity from lead nuclei, in the low background conditions offered by the Gran Sasso underground Laboratory (LNGS), is discussed.

  19. WDM optical steganography based on amplified spontaneous emission noise.

    PubMed

    Wu, Ben; Tait, Alexander N; Chang, Matthew P; Prucnal, Paul R

    2014-10-15

    We propose and experimentally demonstrate a wavelength-division multiplexed (WDM) optical stealth transmission system carried by amplified spontaneous emission (ASE) noise. The stealth signal is hidden in both time and frequency domains by using ASE noise as the signal carrier. Each WDM channel uses part of the ASE spectrum, which provides more flexibility to apply stealth transmission in a public network and adds another layer of security to the stealth channel. Multi-channel transmission also increases the overall channel capacity, which is the major limitation of the single stealth channel transmission based on ASE noise. The relations between spectral bandwidth and coherence length of ASE carrier have been theoretically analyzed and experimentally investigated. PMID:25361121

  20. Optical steganography based on amplified spontaneous emission noise.

    PubMed

    Wu, Ben; Wang, Zhenxing; Tian, Yue; Fok, Mable P; Shastri, Bhavin J; Kanoff, Daniel R; Prucnal, Paul R

    2013-01-28

    We propose and experimentally demonstrate an optical steganography method in which a data signal is transmitted using amplified spontaneous emission (ASE) noise as a carrier. The ASE serving as a carrier for the private signal has an identical frequency spectrum to the existing noise generated by the Erbium doped fiber amplifiers (EDFAs) in the transmission system. The system also carries a conventional data channel that is not private. The so-called "stealth" or private channel is well-hidden within the noise of the system. Phase modulation is used for both the stealth channel and the public channel. Using homodyne detection, the short coherence length of the ASE ensures that the stealth signal can only be recovered if the receiver closely matches the delay-length difference, which is deliberately changed in a dynamic fashion that is only known to the transmitter and its intended receiver. PMID:23389187

  1. Two-atom spontaneous emission in a planar microcavity

    SciTech Connect

    Ujihara, Kikuo [University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 (Japan); Dung, Ho Trung [Institute of Physics, NCST, 1 Mac Dinh Chi Street, District 1, Ho Chi Minh City (Viet Nam)

    2002-11-01

    Spontaneous emission in a planar microcavity by two identical and spatially separated two-level atoms, both of them initially excited, is considered under fourth-order perturbation approximation in atom-field coupling constants. A delay-differential equation with proper retardation times for the probability of both atoms in the upper state is derived and expressions for the emitted-light intensity and spectrum are given. It is numerically shown that, while two-atom cooperation is enhanced for small interatomic distances, the two-atom vacuum Rabi oscillation is somewhat suppressed compared to the single-atom oscillation level when the interatomic separation is close to the cavity transverse coherence length.

  2. Randomness generation based on spontaneous emissions of lasers

    NASA Astrophysics Data System (ADS)

    Zhou, Hongyi; Yuan, Xiao; Ma, Xiongfeng

    2015-06-01

    Random numbers play a key role in information science, especially in cryptography. Based on the probabilistic nature of quantum mechanics, quantum random number generators can produce genuine randomness. In particular, random numbers can be produced from laser phase fluctuations with a very high speed, typically in the Gbps regime. In this work, by developing a physical model, we investigate the origin of the randomness in quantum random number generators based on laser phase fluctuations. We show how the randomness essentially stems from spontaneous emissions. The laser phase fluctuation can be quantitatively evaluated from basic principles and qualitatively explained by the Brownian motion model. After taking account of practical device precision, we show that the randomness generation speed is limited by the finite resolution of detection devices. Our result also provides the optimal experiment design in order to achieve the maximum generation speed.

  3. The influence of spontaneous otoacoustic emissions on the amplitude of transient-evoked emissions.

    PubMed

    Osterhammel, P A; Rasmussen, A N; Olsen, S; Nielsen, L H

    1996-01-01

    The aim of the study was to analyse whether the presence of spontaneous otoacoustic emissions (SOAEs) in a group of normal-hearing adults is related to larger transient evoked otoacoustic emission (TEOAE) amplitudes when compared to a similar adult population without SOAEs. Twenty-four normal-hearing subjects participated in the investigation. They were selected to form two groups of 12, one containing only subjects with measurable spontaneous emissions, the other of members who had no measurable spontaneous emissions. Each group comprised 7 males and 5 females. TEOAEs were recorded in both linear and non-linear mode, and equivalent sound pressure levels in different octave frequency bands were calculated. For each frequency band, the comparison of the equivalent sound pressure levels in the two selected groups showed statistically significant differences. Therefore, when normative TEOAE data were collected with the purpose of establishing a normative reference for the assessment of cochlear hearing loss, it is mandatory to search for and, when pertinent, to compensate for the presence of SOAEs. PMID:8881007

  4. Enhanced spontaneous emission into the mode of a cavity QED system

    E-print Network

    Orozco, Luis A.

    to extract in- formation out of the system. The detection of a spon- taneously emitted photon in cavity QEDEnhanced spontaneous emission into the mode of a cavity QED system M. L. Terraciano, R. Olson Knell by spontaneous emission into a mode of a cavity QED system under weak excitation of the orthogonally polarized

  5. Calculation of spontaneous emission and gain spectra for quantum cascade lasers

    Microsoft Academic Search

    Q. K. Yang; A. Z. Li

    2000-01-01

    In this paper, a quantum cascade laser has been treated as a three-level system, and the calculation of the spontaneous emission and gain spectra has been given. In the calculation, the conduction band nonparabolicity and the injection and exit of electrons have been considered. Results have shown that with increasing injection current, the spontaneous emission peak blue shifts, and the

  6. Casthouse emission control system

    SciTech Connect

    Bernarding, T.F.; Krol, K.K.; Stinson, R.C.; Carson, V.; Hahn, M.

    1993-01-01

    During blast furnace casting operations, the hot metal generates fume and particulate emissions. Environmental regulations require that blast furnace casting emissions by controlled. The casthouse of the No. 3 Blast Furnace at USS/KOBE in Lorain, Ohio was completely redesigned and rebuilt during the modernization of this facility. A state of the art casthouse emission control system was designed and installed as an integral part of the casthouse. Casthouse operations and maintenance, and environmental performance were foremost in the design considerations. This paper discusses the design, operations and results of this newly operational system along with some key design issues that were addressed with the EPA. The casthouse emission system as installed and permitted consists of the following: local evacuated hooding above the taphole to capture drilling, plugging and trough emissions near the taphole; a close fitting evacuated trough cover over that portion of the trough that is not covered by local hooding; an evacuated hood over the iron dam and skimmer; close fitting evacuated iron and slag runners covers on the entire length of the iron and slag runner system to capture iron and slag runner emissions; an evacuated enclosure covering the tilting iron spout to capture iron spout emissions; a baghouse operating at not less than 300,000 ACFM during casting operation to collect the captured emissions.

  7. Spontaneous emission noise in long-range surface plasmon polariton waveguide based optical gyroscope

    PubMed Central

    Wang, Yang-Yang; Zhang, Tong

    2014-01-01

    Spontaneous emission noise is an important limit to the performance of active plasmonic devices. Here, we investigate the spontaneous emission noise in the long-range surface plasmon-polariton waveguide based optical gyroscope. A theoretical model of the sensitivity is established to study the incoherent multi-beam interference of spontaneous emission in the gyroscope. Numerical results show that spontaneous emission produces a drift in the transmittance spectra and lowers the signal-to-noise-ratio of the gyroscope. It also strengthens the shot noise to be the main limit to the sensitivity of the gyroscope for high propagation loss. To reduce the negative effects of the spontaneous emission noise on the gyroscope, an external feedback loop is suggested to estimate the drift in the transmittance spectra and therefor enhance the sensitivity. Our work lays a foundation for the improvement of long-range surface plasmon-polariton gyroscope and paves the way to its practical application. PMID:25234712

  8. Spontaneous emission noise in long-range surface plasmon polariton waveguide based optical gyroscope.

    PubMed

    Wang, Yang-Yang; Zhang, Tong

    2014-01-01

    Spontaneous emission noise is an important limit to the performance of active plasmonic devices. Here, we investigate the spontaneous emission noise in the long-range surface plasmon-polariton waveguide based optical gyroscope. A theoretical model of the sensitivity is established to study the incoherent multi-beam interference of spontaneous emission in the gyroscope. Numerical results show that spontaneous emission produces a drift in the transmittance spectra and lowers the signal-to-noise-ratio of the gyroscope. It also strengthens the shot noise to be the main limit to the sensitivity of the gyroscope for high propagation loss. To reduce the negative effects of the spontaneous emission noise on the gyroscope, an external feedback loop is suggested to estimate the drift in the transmittance spectra and therefor enhance the sensitivity. Our work lays a foundation for the improvement of long-range surface plasmon-polariton gyroscope and paves the way to its practical application. PMID:25234712

  9. Spontaneous emission of NMR signals in hyperpolarized proton spin systems.

    PubMed

    Chen, Hsueh-Ying; Lee, Youngbok; Bowen, Sean; Hilty, Christian

    2011-02-01

    Hyperpolarization of nuclear spins is gaining increasing interest as a tool for improving the signal-to-noise ratio of NMR and MRI. While in principle, hyperpolarized samples are amenable to the same or similar experiments as are used in conventional NMR, the large spin polarization may give rise to unexpected effects. Here, spontaneous emission of signal was observed from proton spin systems, which were hyperpolarized to negative spin temperature by dynamic nuclear polarization (DNP). An unexpected feature of these emissions is that, without any radio-frequency excitation, multiple beats arise that cannot be explained by the Bloch equations with radiation damping. However, we show that a simple modification to these equations, which takes into account an additional supply of hyperpolarized magnetization from a reservoir outside of the active detection region, can phenomenologically describe the observed signal. The observed effect demonstrates that even well-known mechanisms of spin evolution can give rise to unexpected effects when working with hyperpolarized samples, which may need to be addressed through the development of new experimental techniques. PMID:21145766

  10. An alternative realization of spontaneous emission cancelation via Field Generated Coherence (FGC)

    E-print Network

    Fazal Ghafoor

    2013-03-21

    In contrast to the traditional Spontaneous Generated Coherence (SGC), Field Generated Coherence (FGC)-based atomic scheme is presented for spontaneous emission cancellation. It is easy to achieve externally controllable experimental trapping condition in this 4-field-driven 5-level atomic system. Consequently, due to the FGC the decay from the central dressed \\emph{bare-energy-state} of the set of upper three closely spaced hyperfine decaying states of Sodium D2 line is completely cancelled under the trapping condition, exhibiting a novel phenomenon of a \\textit{dark bare-energy-state}% . Extending to an atomic system of simple probability loss, based on Sodium D1 line, the bright atom can also be darkened under its trapping condition, representing another experimentally viable, novel and interesting phenomenon.

  11. Self-amplified spontaneous emission free electron laser devices and nonideal electron beam transport

    NASA Astrophysics Data System (ADS)

    Lazzarino, L. L.; Di Palma, E.; Anania, M. P.; Artioli, M.; Bacci, A.; Bellaveglia, M.; Chiadroni, E.; Cianchi, A.; Ciocci, F.; Dattoli, G.; Di Giovenale, D.; Di Pirro, G.; Ferrario, M.; Gatti, G.; Giannessi, L.; Mostacci, A.; Musumeci, P.; Petralia, A.; Petrillo, V.; Pompili, R.; Rau, J. V.; Rossi, A. R.; Sabia, E.; Vaccarezza, C.; Villa, F.

    2014-11-01

    We have developed, at the SPARC test facility, a procedure for a real time self-amplified spontaneous emission free electron laser (FEL) device performance control. We describe an actual FEL, including electron and optical beam transport, through a set of analytical formulas, allowing a fast and reliable on-line "simulation" of the experiment. The system is designed in such a way that the characteristics of the transport elements and the laser intensity are measured and adjusted, via a real time computation, during the experimental run, to obtain an on-line feedback of the laser performances. The detail of the procedure and the relevant experimental results are discussed.

  12. Vacuum field energy and spontaneous emission in anomalously dispersive cavities

    SciTech Connect

    Bradshaw, Douglas H.; Di Rosa, Michael D. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2011-05-15

    Anomalously dispersive cavities, particularly white-light cavities, may have larger bandwidth to finesse ratios than their normally dispersive counterparts. Partly for this reason, they have been proposed for use in laser interferometer gravitational-wave observatory (LIGO)-like gravity-wave detectors and in ring-laser gyroscopes. In this paper we analyze the quantum noise associated with anomalously dispersive cavity modes. The vacuum field energy associated with a particular cavity mode is proportional to the cavity-averaged group velocity of that mode. For anomalously dispersive cavities with group index values between 1 and 0, this means that the total vacuum field energy associated with a particular cavity mode must exceed ({h_bar}/2{pi}){omega}/2. For white-light cavities in particular, the group index approaches zero and the vacuum field energy of a particular spatial mode may be significantly enhanced. We predict enhanced spontaneous emission rates into anomalously dispersive cavity modes and broadened laser linewidths when the linewidth of intracavity emitters is broader than the cavity linewidth.

  13. Automotive Emission Control.

    ERIC Educational Resources Information Center

    Lee, Billy D.; Ragazzi, Ronald

    This guide designed to assist teachers in improving instruction in the area of automotive emission control curriculum includes four areas. Each area consists of one or more units of instruction, with each instructional unit including some or all of the following basic components: Performance objectives, suggested activities for teacher and…

  14. Spectral modulation of higher harmonic spontaneous emission from an optical klystron.

    PubMed

    Sei, Norihiro; Ogawa, Hiroshi; Yamada, Kawakatsu; Koike, Masaki; Ohgaki, Hideaki

    2014-07-01

    Higher harmonics of spontaneous emission from an optical klystron have been observed. The modulation factor of the spontaneous emission spectrum for the higher harmonics can be described by considering the observation system. When the dispersive gap of the optical klystron was fixed, the microstructure interval of the spontaneous emission spectrum at a certain resonant wavelength became narrower as the order of the higher harmonic became larger. Some unique characteristics of the higher harmonics have been clarified, and these studies are likely to contribute to the development of free-electron lasers using higher harmonics of an optical klystron in the shorter-wavelengths region. PMID:24971958

  15. Fast and bright spontaneous emission of Er3+ ions in metallic nanocavity

    PubMed Central

    Song, Jung-Hwan; Kim, Jisu; Jang, Hoon; Yong Kim, In; Karnadi, Indra; Shin, Jonghwa; Shin, Jung H.; Lee, Yong-Hee

    2015-01-01

    By confining light in a small cavity, the spontaneous emission rate of an emitter can be controlled via the Purcell effect. However, while Purcell factors as large as ?10,000 have been predicted, actual reported values were in the range of about 10–30 only, leaving a huge gap between theory and experiment. Here we report on enhanced 1.54-?m emission from Er3+ ions placed in a very small metallic cavity. Using a cavity designed to enhance the overall Purcell effect instead of a particular component, and by systematically investigating its photonic properties, we demonstrate an unambiguous Purcell factor that is as high as 170 at room temperature. We also observe >90 times increase in the far-field radiant flux, indicating that as much as 55% of electromagnetic energy that was initially supplied to Er3+ ions in the cavity escape safely into the free space in just one to two optical cycles. PMID:25940839

  16. A semi-analytical approach for evaluating effects of amplified spontaneous emission on characteristics of Q-switched lasers

    SciTech Connect

    Razzaghi, D; Hajiesmaeilbaigi, F; Ruzbehani, M [Laser and Optics Research School, P.O. Box 11155-3486, Tehran (Iran, Islamic Republic of)

    2012-08-31

    Possible effects of amplified spontaneous emission on output pulse characteristics of a Q-switched laser are discussed within the framework of a semi-analytical approach. It is shown that output energy decreases almost exponentially with average path length of the spontaneously emitted photons which in turn depends on geometrical specification and active medium properties as well as on optical finishing of the surfaces (for solid-state lasers). Optimal coupling dependence on the average path length is also investigated and shown to increase with average path length increment. (control of laser radiation parameters)

  17. Spontaneous emission near the electron plasma frequency in a plasma with a runaway electron tail

    NASA Technical Reports Server (NTRS)

    Freund, H. P.; Lee, L. C.; Wu, C. S.

    1978-01-01

    Spontaneous emission of radiation with frequencies near the electron plasma frequency is studied for a plasma which consists of both thermal and runaway electrons. It is found that a substantial enhancement of the spontaneous radiation intensity can occur in this frequency regime via a Cherenkov resonance with the runaway electrons. Numerical analysis indicates that, for reasonable estimates of densities and energies, the plasma-frequency radiation can attain levels greater than the peak thermal emission at the second gyroharmonic.

  18. Si spontaneous emission during RTP and its impact on low-temperature pyrometry

    Microsoft Academic Search

    J. P. Li; Aaron Hunter; Rajesh Ramanujam

    2008-01-01

    Si fluorescence or spontaneous emission was discovered during the development of lower-temperature pyrometer. To reveal unambiguously the Si spontaneous emission, a high-power 980nm laser is used together with a high sensitivity IR spectrometer. Clear Si fluorescence spectra with peaks at ?1140nm were obtained at different Si temperatures. The Si fluorescence peaks shift to longer wavelength, in agreement with Si bandgap

  19. Enhanced amplified spontaneous emission from colloidal quantum dots in all-dielectric monolithic microcavities

    NASA Astrophysics Data System (ADS)

    Goldberg, David; Menon, Vinod M.

    2013-02-01

    We report enhanced amplified spontaneous emission from CdSe/ZnS (core/shell) quantum dots embedded in an all-dielectric microcavity. The vertical cavity surface emitting structure was grown via plasma enhanced chemical vapor deposition and the quantum dots were sandwiched in the cavity layer via dip coating. The enhancement in emission is observed when the cavity mode is in resonance with the biexciton energy. The microcavity shows a factor of two improvement in the slope efficiency of amplified spontaneous emission along with significant modification in the directionality of the emission.

  20. Effect of spontaneous emission in hydrogenlike magnesium and aluminum x-ray laser schemes

    SciTech Connect

    Eder, D.C.; Rosen, M.D.; Lee, R.W.; Trebes, J.E.; Ceglio, N.M.; Eckart, M.J.; Kauffman, R.L.; MacGowan, B.J.; Matthews, D.L.

    1987-12-01

    Two-dimensional modeling of magnesium exploding-foil experiments shows that spontaneous emission from regions outside of line focus makes the measurement of induced emission and gain difficult. An improved target design is proposed that solves the spontaneous-emission problem by replacing the foil by a ribbon. The new targets consist of an aluminum ribbon on a Formvar sheet with the potential 4--3 lasing line at III A for H-like Al. We comment on what conditions are required for lasing in the 3--2 line of H-like Al at 39 A.

  1. Spontaneous Neoplasms in Control Wistar Rats: A Comparison of Reviews

    Microsoft Academic Search

    James Poteracki; Kathleen M. Walsh

    1998-01-01

    Spontaneous neoplasms in 930 control Wistar rats from five carcinogenicity bioassays conducted between 1990 and 1995 were reviewed and compared with review findings in studies between 1980 and 1990. Mean survival at 104 weeks was 55% for males and 60% for females, similar to that of the previous review. A total of 1599 neoplasms was diagnosed in 361 (78%) male

  2. Protecting remote atomic entanglement against spontaneous emission by separated photonic pulses

    NASA Astrophysics Data System (ADS)

    Zong, Xiao-Lan; Du, Chao-Qun; Yang, Ming; Zhang, Gang; Yang, Qing; Cao, Zhuo-Liang

    2015-07-01

    We study the entanglement dynamics between two spatially separated atoms trapped in two separate optical cavities. Based on cavity-assisted interactions between the atoms and separated photonic pulses, we propose a scheme for the implemention of a controlled-phase-flip gate (CPF gate) between each of the atoms and the photonic pulse to protect the remote atomic quantum entanglement against the decaying caused by spontaneous emission. What we need to do is to shoot the horizontally polarized photons onto the cavity mirror successively, plus a train of Hadamard operations on the atoms, and no measurement is needed here. It is shown that the quantum entanglement of the two remote atoms can be protected effectively in this way. We also extend our scheme to the case of weak coupling and low Q cavity cases. The simplicity of the current scheme may warrant its experimental realization.

  3. Spontaneous emission lifetimes in the ground electronic states of HD/+/ and H2/+/a

    NASA Technical Reports Server (NTRS)

    Peek, J. M.; Hashemi-Attar, A.-R.; Beckel, C. L.

    1979-01-01

    Because of their simplicity, H2(+) and its isotopic species are of particular interest to molecular theorists and experimentalists. If these ions are formed in excited vibrational states under conditions of highly improbable electron-ion recombination or other reactions, spontaneous emission will occur. The present note calculates the (vibrational quantum number, J prime = 0) state lifetimes under spontaneous emission for all 22 excited vibrations of HD(+) and all 19 excited vibrations of H2(+) in their ground electron states. The lifetimes presented in Tables I and III justify the assumption that spontaneous radiative processes are unimportant under certain realizable conditions. When spontaneous radiation plays a role, however, minimum lifetime at intermediate vibrational quantum number could lead to unusual vibrational distribution functions.

  4. Spontaneous emission of a chiral molecule near a cluster of two chiral spherical particles

    NASA Astrophysics Data System (ADS)

    Guzatov, D. V.; Klimov, V. V.

    2015-03-01

    We have obtained and investigated analytical expressions for the radiative spontaneous decay rate of a chiral (optically active) molecule located near a cluster of two identical chiral (biisotropic) spherical particles. It is found that the composition of the particles, their location and size have a significant effect on the spontaneous emission of chiral molecules. In particular, it is shown that in the case of nanoparticles of chiral metamaterials, the radiative spontaneous decay rate for the 'right-' and 'left-handed' enantiomers of chiral molecules located in the gap of the cluster are significantly different.

  5. Spontaneous emission in a cylindrical nanocavity: ab initio analytical approach

    NASA Astrophysics Data System (ADS)

    Bordo, Vladimir G.

    2012-04-01

    The rigorous analytical approach for the calculation of the spontaneous decay rate for an emitter located in a cylindrical cavity of arbitrary diameter and length is developed. The approach is based on the dyadic Green's function of the Helmholtz equation which is obtained by introducing the fictitious surface current sheets at both ends of the nanocavity. The Hertz vector potentials which describe the electromagnetic field in the system are found as Fourier integrals over the path in the complex plane of the propagation constant. The integral equation which determines the field Fourier transforms is derived. The Green's function is then used to calculate the field susceptibility and the spontaneous decay rate of an emitter located inside a nanocavity. The general theory is illustrated by the calculations for the system which models an InAs quantum dot embedded in a GaAs nanowire.

  6. Ultrafast spontaneous emission of copper-doped silicon enhanced by an optical nanocavity

    PubMed Central

    SUMIKURA, HISASHI; KURAMOCHI, EIICHI; TANIYAMA, HIDEAKI; NOTOMI, MASAYA

    2014-01-01

    Dopants in silicon (Si) have attracted attention in the fields of photonics and quantum optics. However, the optical characteristics are limited by the small spontaneous emission rate of dopants in Si. This study demonstrates a large increase in the spontaneous emission rate of copper isoelectronic centres (Cu-IECs) doped into Si photonic crystal nanocavities. In a cavity with a quality factor (Q) of ~16,000, the photoluminescence (PL) lifetime of the Cu-IECs is 1.1?ns, which is 30 times shorter than the lifetime of a sample without a cavity. The PL decay rate is increased in proportion to Q/Vc (Vc is the cavity mode volume), which indicates the Purcell effect. This is the first demonstration of a cavity-enhanced ultrafast spontaneous emission from dopants in Si, and it may lead to the development of fast and efficient Si light emitters and Si quantum optical devices based on dopants with efficient optical access. PMID:24853336

  7. Control of Emissions

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor); Chung, Landy (Inventor)

    2013-01-01

    Methods and apparatus utilizing chlorine dioxide and hydrogen peroxide are useful to reduce NOx emissions, as well as SOx and mercury (or other heavy metal) emissions, from combustion flue gas streams.

  8. Simulations of the spontaneous emission of a quantum dot near a gap plasmon waveguide

    NASA Astrophysics Data System (ADS)

    Perera, Chamanei S.; Vernon, Kristy C.; Mcleod, Angus

    2014-02-01

    In this paper, we modeled a quantum dot at near proximity to a gap plasmon waveguide to study the quantum dot-plasmon interactions. Assuming that the waveguide is single mode, this paper is concerned about the dependence of spontaneous emission rate of the quantum dot on waveguide dimensions such as width and height. We compare coupling efficiency of a gap waveguide with symmetric configuration and asymmetric configuration illustrating that symmetric waveguide has a better coupling efficiency to the quantum dot. We also demonstrate that optimally placed quantum dot near a symmetric waveguide with 50 nm × 50 nm cross section can capture 80% of the spontaneous emission into a guided plasmon mode.

  9. Spontaneous synchrotron emission from a plasma with an energetic runaway electron tail

    NASA Technical Reports Server (NTRS)

    Freund, H. P.; Dillenburg, D.; Wu, C. S.; Lee, L. C.

    1978-01-01

    The emissivity of spontaneous synchrotron radiation is computed for a plasma consisting of a background thermal plasma in addition to an energetic runaway electron component. The analysis is performed for both the ordinary and extraordinary modes, for frequencies in the vicinity of the electron plasma frequency and the higher harmonics of the electron gyrofrequency, and for the case when the electron plasma frequency is approximately the same as or smaller than the cyclotron frequency. The relativistic gyroresonance with the runaway electrons is found to result in a level of spontaneous emission which, for frequencies in the neighborhood of the electron plasma frequency, is significantly enhanced over the thermal radiation.

  10. Advanced Emissions Control Development Program

    SciTech Connect

    G. A. Farthing; G. T. Amrhein; G. A. Kudlac; D. A. Yurchison; D. K. McDonald; M. G. Milobowski

    2001-03-31

    The primary objective of the Advanced Emissions Control Development Program (AECDP) is to develop practical, cost-effective strategies for reducing the emissions of hazardous air pollutants (HAPs, or air toxics) from coal-fired boilers. This objective is being met by identifying ways to effectively control air toxic emissions through the use of conventional flue gas cleanup equipment such as electrostatic precipitators (ESPs), fabric filters (fabric filters), and wet flue gas desulfurization (wet FGD) systems. Development work initially concentrated on the capture of trace metals, hydrogen chloride, and hydrogen fluoride. Recent work has focused almost exclusively on the control of mercury emissions.

  11. Electrically controllable spontaneous magnetism in nanoscale mixed phase multiferroics.

    PubMed

    He, Q; Chu, Y-H; Heron, J T; Yang, S Y; Liang, W I; Kuo, C Y; Lin, H J; Yu, P; Liang, C W; Zeches, R J; Kuo, W C; Juang, J Y; Chen, C T; Arenholz, E; Scholl, A; Ramesh, R

    2011-01-01

    Magnetoelectrics and multiferroics present exciting opportunities for electric-field control of magnetism. However, there are few room-temperature ferromagnetic-ferroelectrics. Among the various types of multiferroics the bismuth ferrite system has received much attention primarily because both the ferroelectric and the antiferromagnetic orders are quite robust at room temperature. Here we demonstrate the emergence of an enhanced spontaneous magnetization in a strain-driven rhombohedral and super-tetragonal mixed phase of BiFeO?. Using X-ray magnetic circular dichroism-based photoemission electron microscopy coupled with macroscopic magnetic measurements, we find that the spontaneous magnetization of the rhombohedral phase is significantly enhanced above the canted antiferromagnetic moment in the bulk phase, as a consequence of a piezomagnetic coupling to the adjacent tetragonal-like phase and the epitaxial constraint. Reversible electric-field control and manipulation of this magnetic moment at room temperature is also shown. PMID:21407191

  12. Effect of surface-plasmon polaritons on spontaneous emission and intermolecular energy-transfer rates in multilayered geometries

    SciTech Connect

    Marocico, C. A.; Knoester, J. [Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, NL-9747 AG Groningen (Netherlands)

    2011-11-15

    We use a Green's tensor method to investigate the spontaneous emission rate of a molecule and the energy-transfer rate between molecules placed in two types of layered geometries: a slab geometry and a planar waveguide. We focus especially on the role played by surface-plasmon polaritons in modifying the spontaneous emission and energy-transfer rates as compared to free space. In the presence of more than one interface, the surface-plasmon polariton modes split into several branches, and each branch can contribute significantly to modifying the electromagnetic properties of atoms and molecules. Enhancements of several orders of magnitude both in the spontaneous emission rate of a molecule and the energy-transfer rate between molecules are obtained and, by tuning the parameters of the geometry, one has the ability to control the range and magnitude of these enhancements. For the energy-transfer rate interference effects between contributions of different plasmon-polariton branches are observed as oscillations in the distance dependence of this rate.

  13. Spontaneous emission from two coaxial disks of atoms

    NASA Astrophysics Data System (ADS)

    Berman, P. R.

    2013-10-01

    The spontaneous radiation pattern is calculated for two coaxial disks of atoms, separated by a distance L. The atoms are modeled as having J=0 ground states and J=1 excited states. At t=0 the atoms in one disk are excited to their m=1 excited-state sublevels, while the atoms in the second disk can be either in their ground or excited states. The manner in which the atoms in each disk modify the radiation pattern of the atoms in the other disk is described. It is shown, for example, that when the atoms in the second disk are in their ground states, they can still lead to an increase in the signal radiated by the first disk in certain directions. The dependence on the Fresnel number of the radiation pattern is calculated. Moreover, it is shown that analytic expressions can be obtained for the radiation pattern if the disks are replaced by Gaussian density distributions.

  14. Subradiant spontaneous undulator emission through collective suppression of shot noise

    NASA Astrophysics Data System (ADS)

    Ratner, D.; Hemsing, E.; Gover, A.; Marinelli, A.; Nause, A.

    2015-05-01

    The phenomenon of Dicke's subradiance, in which the collective properties of a system suppress radiation, has received broad interest in atomic physics. Recent theoretical papers in the field of relativistic electron beams have proposed schemes to achieve subradiance through suppression of shot noise current fluctuations. The resulting "quiet" beam generates less spontaneous radiation than emitted even by a shot noise beam when oscillating in an undulator. Quiet beams could have diverse accelerator applications, including lowering power requirements for seeded free-electron lasers and improving efficiency of hadron cooling. In this paper we present experimental observation of a strong reduction in undulator radiation, demonstrating the feasibility of noise suppression as a practical tool in accelerator physics.

  15. Spontaneous otoacoustic emissions, threshold microstructure, and psychophysical tuning over a wide frequency range in humansa

    PubMed Central

    Baiduc, Rachael R.; Lee, Jungmee; Dhar, Sumitrajit

    2014-01-01

    Hearing thresholds have been shown to exhibit periodic minima and maxima, a pattern known as threshold microstructure. Microstructure has previously been linked to spontaneous otoacoustic emissions (SOAEs) and normal cochlear function. However, SOAEs at high frequencies (>4 kHz) have been associated with hearing loss or cochlear pathology in some reports. Microstructure would not be expected near these high-frequency SOAEs. Psychophysical tuning curves (PTCs), the expression of frequency selectivity, may also be altered by SOAEs. Prior comparisons of tuning between ears with and without SOAEs demonstrated sharper tuning in ears with emissions. Here, threshold microstructure and PTCs were compared at SOAE frequencies ranging between 1.2 and 13.9 kHz using subjects without SOAEs as controls. Results indicate: (1) Threshold microstructure is observable in the vicinity of SOAEs of all frequencies; (2) PTCs are influenced by SOAEs, resulting in shifted tuning curve tips, multiple tips, or inversion. High frequency SOAEs show a greater effect on PTC morphology. The influence of most SOAEs at high frequencies on threshold microstructure and PTCs is consistent with those at lower frequencies, suggesting that high-frequency SOAEs reflect the same cochlear processes that lead to SOAEs at lower frequencies. PMID:24437770

  16. Controlled Emission Dispatch

    Microsoft Academic Search

    Jerome Delson

    1974-01-01

    A method is described for commiting generators and scheduling their output so as to comply with environmental objectives such as limitations on emission of oxides of sulfur, oxides of nitrogen or discharge of heat into watercourses. The limitations may apply to emissions or to resulting ambient concentrations and may apply simultaneously to more than one type of residual. The method

  17. Frequency-Dependent Spontaneous Emission Rate from CdSe and CdTe Nanocrystals: Influence of Dark States

    E-print Network

    Vos, Willem L.

    Frequency-Dependent Spontaneous Emission Rate from CdSe and CdTe Nanocrystals: Influence of Dark studied the rate of spontaneous emission from colloidal CdSe and CdTe nanocrystals at room temperature, in practice CdTe and CdSe. Because of quantum confinement, nanocrystals pos- sess discrete electron and hole

  18. Spontaneous emission lifetime distribution of infinite line antennas in two-dimensional photonic crystals with finite size

    Microsoft Academic Search

    Xingsheng Xu; Yiquan Wang

    2007-01-01

    The authors calculate the lifetime distribution functions of spontaneous emission from infinite line antennas embedded in two-dimensional disordered photonic crystals with finite size. The calculations indicate the coexistence of both accelerated and inhibited decay processes in disordered photonic crystals with finite size. The decay behavior of the spontaneous emission from infinite line antennas changes significantly by varying factors such as

  19. Nonlinear optical effects in spontaneous and stimulated emission from excited two-band intrinsic semiconductor

    Microsoft Academic Search

    V. Cheltsov

    2005-01-01

    The basic results of theoretical nonperturbative analysis of spontaneous and stimulated emission from two-band excited intrinsic semiconductor interacting with a single mode of radiation field in a lossless micro-cavity are presented. The self-consistent dynamics of the coupled system ''semiconductor + single mode radiation field\\

  20. Coherent photon transport from spontaneous emission in one-dimensional waveguides

    Microsoft Academic Search

    J. T. Shen; Shanhui Fan

    2005-01-01

    A two-level system coupled to a one-dimensional continuum is investigated. By using a real-space model Hamiltonian, we show that spontaneous emission can coherently interfere with the continuum modes and gives interesting transport properties. The technique is applied to various related problems with different configurations, and analytical solutions are given.

  1. Noise-color-induced quenching of fluctuations in a correlated spontaneous-emission laser model

    Microsoft Academic Search

    R. G. K. Habiger; H. Risken; M. James; Frank Moss; W. Schleich

    1990-01-01

    We show via (1) an approximate, analytical technique, (2) a formally exact matrix continued-fraction analysis, and (3) an analog simulation of the classical Langevin equation of a correlated spontaneous-emission laser (CEL) that noise of nonzero correlation time leads to an enhancement of the characteristic CEL noise quenching.

  2. Spontaneous emission of Bloch oscillation radiation from a single energy band

    Microsoft Academic Search

    V. N. Sokolov; L. Zhou; G. J. Iafrate; J. B. Krieger

    2006-01-01

    A theory for the spontaneous emission of radiation for a Bloch electron traversing a single energy band under the influence of a constant external electric field is presented. The constant external electric field is described in the vector potential gauge. The quantum radiation field is described by the free space quantized electromagnetic field in the Coulomb gauge. The instantaneous eigenstates

  3. Intensity and spatial modulation of spontaneous emission in GaAs by field aperture selecting transport

    E-print Network

    Woodall, Jerry M.

    Intensity and spatial modulation of spontaneous emission in GaAs by field aperture selecting carrier recombination in a semiconductor device is introduced. This process utilizes an electric field of the semiconductor. A short burst of light is allowed to escape through the surface of the device as the packet

  4. Observation of Spectral Hole Burning in the Amplified Spontaneous Emission Spectrum of Erbium Doped Fibers

    Microsoft Academic Search

    W. A. Arellano; M. O. Berendt; A. A. Rieznik; H. L. Fragnito

    2000-01-01

    We report on room temperature observation of spectral hole burning in the Amplified Spontaneous Emission spectrum of Erb ium Doped Fiber Amplifiers (EDFA). From measurements of the hole width we determine an homogeneous linewidth of 2 nm for the 1530 nm transition.

  5. Electrically Controllable Spontaneous Magnetism in Nanoscale Mixed Phase Multiferroics

    SciTech Connect

    He, Q.; Chu, Y. H.; Heron, J. T.; Yang, S. Y.; Wang, C. H.; Kuo, C. Y.; Lin, H. J.; Yu, P.; Liang, C. W.; Zeches, R. J.; Chen, C. T.; Arenholz, E.; Scholl, A.; Ramesh, R.

    2010-08-02

    The emergence of enhanced spontaneous magnetic moments in self-assembled, epitaxial nanostructures of tetragonal (T-phase) and rhombohedral phases (R-phase) of the multiferroic BiFeO{sub 3} system is demonstrated. X-ray magnetic circular dichroism based photoemission electron microscopy (PEEM) was applied to investigate the local nature of this magnetism. We find that the spontaneous magnetization of the R-phase is significantly enhanced above the canted antiferromagnetic moment in the bulk phase, as a consequence of a piezomagnetic coupling to the adjacent T-phase and the epitaxial constraint. Reversible electric field control and manipulation of this magnetic moment at room temperature is shown using a combination of piezoresponse force microscopy and PEEM studies.

  6. Optical instabilities and spontaneous light emission in moving media

    NASA Astrophysics Data System (ADS)

    Silveirinha, Mario

    2015-03-01

    We show that when an uncharged plasmonic material is set in relative motion with respect to another uncharged polarizable body the system may be electromagnetically unstable. Particularly, when the relative velocity of the two bodies is enforced to remain constant the system may support natural oscillations that grow exponentially with time, even in presence of realistic material loss and dispersion. It is proven that a friction-type force acts on the moving bodies to oppose their relative motion. Hence, the optical instabilities result from the conversion of kinetic energy into electromagnetic energy. This new purely classical phenomenon is analogous to the Cherenkov and Smith-Purcell effects but for uncharged polarizable matter. We link the optical instabilities to a spontaneous parity-time symmetry breaking of the system, and demonstrate the possibility of optical amplification of a light pulse in the broken parity-time symmetry regime. This work is supported in part by Fundação para a Ciência e a Tecnologia Grant Number PTDC/EEI-TEL/2764/2012.

  7. Plasmonic engineering of spontaneous emission from silicon nanocrystals

    PubMed Central

    Goffard, Julie; Gérard, Davy; Miska, Patrice; Baudrion, Anne-Laure; Deturche, Régis; Plain, Jérôme

    2013-01-01

    Silicon nanocrystals offer huge advantages compared to other semi-conductor quantum dots as they are made from an abundant, non-toxic material and are compatible with silicon devices. Besides, among a wealth of extraordinary properties ranging from catalysis to nanomedicine, metal nanoparticles are known to increase the radiative emission rate of semiconductor quantum dots. Here, we use gold nanoparticles to accelerate the emission of silicon nanocrystals. The resulting integrated hybrid emitter is 5-fold brighter than bare silicon nanocrystals. We also propose an in-depth analysis highlighting the role of the different physical parameters in the photoluminescence enhancement phenomenon. This result has important implications for the practical use of silicon nanocrystals in optoelectronic devices, for instance for the design of efficient down-shifting devices that could be integrated within future silicon solar cells. PMID:24037020

  8. Decoherence of Quantum Tunneling Induced by Spontaneous Emission

    NASA Astrophysics Data System (ADS)

    Zheng, Li; Xiao, Zhi-Hong; Liu, Yu-Jie; Shi, Ying

    2015-07-01

    We study the decoherence dynamics of quantum tunneling of a two-level atom coupled into a single-mode electromagnetic field. Atomic internal and external degrees are entangled with the cavity field due to recoil during emission of a photon. We show that the quantum tunneling period depends on the distance between the two wells, and the tunneling process itself may or may not decohere depending on the distance between the two wells of the external potential compared to the wavelength corresponding to the internal transition.

  9. Nonresonant enhancement of spontaneous emission in metal-dielectric-metal plasmon waveguide structures

    SciTech Connect

    Jun, Y.C.

    2010-03-02

    We theoretically investigate the spontaneous emission process of an optical, dipolar emitter in metal-dielectric-metal slab and slot waveguide structures. We find that both structures exhibit strong emission enhancements at nonresonant conditions, due to the tight confinement of modes between two metallic plates. The large enhancement of surface plasmon-polariton excitation enables dipole emission to be preferentially coupled into plasmon waveguide modes. These structures find applications in creating nanoscale local light sources or in generating guided single plasmons in integrated optical circuits.

  10. Preparation of three-dimensional entanglement for distant atoms in coupled cavities via atomic spontaneous emission and cavity decay

    E-print Network

    Shi-Lei Su; Xiao-Qiang Shao; Hong-Fu Wang; Shou Zhang

    2014-08-21

    We propose a dissipative scheme to prepare a three-dimensional entangled state for two atoms trapped in separate coupled cavities. Our work shows that both atomic spontaneous emission and cavity decay, which are two typical obstacles in unitary-dynamics-based schemes, could be utilized as resources for high-dimensional entangled state preparation without specifying initial state and controlling time precisely. Final numerical simulation with one group of experimental parameters indicates that the performance of our scheme is better than the unitary-dynamics-based scheme.

  11. Spontaneous emission lifetime distribution of infinite line antennas in two-dimensional photonic crystals with finite size

    NASA Astrophysics Data System (ADS)

    Xu, Xingsheng; Wang, Yiquan

    2007-07-01

    The authors calculate the lifetime distribution functions of spontaneous emission from infinite line antennas embedded in two-dimensional disordered photonic crystals with finite size. The calculations indicate the coexistence of both accelerated and inhibited decay processes in disordered photonic crystals with finite size. The decay behavior of the spontaneous emission from infinite line antennas changes significantly by varying factors such as the line antennas' positions in the disordered photonic crystal, the shape of the crystal, the filling fraction, and the dielectric constant. Moreover, the authors analyze the effect of the degree of disorder on spontaneous emission.

  12. Experimental Demonstration of Enhanced Self-Amplified Spontaneous Emission by an Optical Klystron

    NASA Astrophysics Data System (ADS)

    Penco, G.; Allaria, E.; De Ninno, G.; Ferrari, E.; Giannessi, L.

    2015-01-01

    We report the first experimental evidence of enhancement of self-amplified spontaneous emission, due to the use of an optical klystron. In this free-electron laser scheme, a relativistic electron beam passes through two undulators, separated by a dispersive section. The latter converts the electron-beam energy modulation produced in the first undulator in density modulation, thus enhancing the free-electron laser gain. The experiment has been carried out at the FERMI facility in Trieste. Powerful radiation has been produced in the extreme ultraviolet range, with an intensity a few orders of magnitude larger than in pure self-amplified spontaneous emission mode. Data have been benchmarked with an existing theoretical model.

  13. Complementary coding optical stealth transmission based on amplified spontaneous emission light source.

    PubMed

    Zhu, Huatao; Wang, Rong; Pu, Tao; Chen, Yinfang; Fang, Tao; Zheng, Jilin; Su, Guorui

    2014-11-17

    Complementary encoder of stealth signal is proposed and demonstrated for coding, modulating and enhancing the privacy of optical stealth transmission. With complementary encoding, the stealth signal carried by amplified spontaneous emission (ASE) light keeps the same characteristic to ASE noise and can be concealed well under public channel. The experiment results demonstrate the feasibility of the scheme and show the stealth signal has the same impact on public channel in transmission performance, compared to the ASE noise. PMID:25402076

  14. Spontaneous emission and gain in a waveguide free-electron laser

    Microsoft Academic Search

    William J. Golightly; Sally K. Ride

    1991-01-01

    A free-electron laser (FEL) enclosed in a waveguide of narrowly spaced parallel plates has been proposed as a compact, coherent source of far-infrared radiation. The spontaneous emission and small-signal gain of such a device are analyzed. Maxwell's equations are solved for the fields of a relativistic electron beam passing through a linearly polarized undulator in the presence of a parallel-plane

  15. Spectrum of spontaneous emission into the mode of a cavity QED system

    E-print Network

    M. L. Terraciano; R. Olson; D. L. Freimund; L. A. Orozco; P. R. Rice

    2006-01-10

    We study the probe spectrum of light generated by spontaneous emission into the mode of a cavity QED system. The probe spectrum has a maximum on-resonance when the number of inverted atoms for an input drive is maximal. For a larger number of atoms N, the maximum splits and develops into a doublet, but its frequencies are different from those of the so-called vacuum Rabi splitting.

  16. Radiation from an N-Atom System. II. Spontaneous Emission from a Pair of Atoms

    Microsoft Academic Search

    R. H. Lehmberg

    1970-01-01

    Using the formalism developed earlier, we treat spontaneous emission from a pair of identical two-level atoms A1, A2, whose separation r21 can be comparable to the wavelength lambda. We obtain expressions for time-dependent intensities and damping rates with the initial conditions (a) both atoms inverted, (b) prior excitation by a short 12pi pulse, and (c) only A1 inverted. The results

  17. Exponential Gain and Saturation of a Self-Amplified Spontaneous Emission Free-Electron Laser

    Microsoft Academic Search

    S. V. Milton; E. Gluskin; N. D. Arnold; C. Benson; W. Berg; S. G. Biedron; M. Borland; Y.-C. Chae; R. J. Dejus; P. K. Den Hartog; B. Deriy; M. Erdmann; Y. I. Eidelman; M. W. Hahne; Z. Huang; K.-J. Kim; J. W. Lewellen; Y. Li; A. H. Lumpkin; O. Makarov; E. R. Moog; A. Nassiri; V. Sajaev; R. Soliday; B. J. Tieman; E. M. Trakhtenberg; G. Travish; I. B. Vasserman; N. A. Vinokurov; X. J. Wang; G. Wiemerslage; B. X. Yang

    2001-01-01

    Self-amplified spontaneous emission in a free-electron laser has been proposed for the generation of very high brightness coherent x-rays. This process involves passing a high-energy, high-charge, short-pulse, low-energy-spread, and low-emittance electron beam through the periodic magnetic field of a long series of high-quality undulator magnets. The radiation produced grows exponentially in intensity until it reaches a saturation point. We report

  18. Low threshold amplified spontaneous emission from near-infrared dye-doped polymeric waveguide

    Microsoft Academic Search

    K. Yamashita; T. Kuro; K. Oe; H. Yanagi

    2006-01-01

    We have investigated near-infrared light amplification in a dye-doped polymeric waveguide structure under optical pumping. Amplified spontaneous emission (ASE) at ~800 nm was observed in poly(vinyl-pyrrolidone) thin film with organic dye LDS798. The ASE threshold energy was as low as ~12 muJ\\/cm2, which is about one-tenth of previously reported values for infrared-dye-doped polymeric waveguides. This low threshold ASE comes from

  19. On the achievable information rate of asymmetric optical fiber channels with amplifier spontaneous emission noise

    Microsoft Academic Search

    Jing Li

    2003-01-01

    This work is motivated by the need to understand the fundamental limit of channel capacities of optical fiber communication channels where amplified spontaneous emission (ASE) noise is dominant and to understand how much has been achieved by the state-of-the-art forward error correction (FEC) coding techniques. Two most commonly used channel models, the Chi-square channel and its Gaussian approximation, are examined.

  20. Stabilization of the output power from a Raman fiber laser by generated-amplified spontaneous emission

    Microsoft Academic Search

    G. Sun; D. Hwang; Y. Chung

    2008-01-01

    In this work, an optical approach is theoretically presented for suppressing the low-frequency relative intensity noise transfer\\u000a from the pump source to the Raman fiber laser output. This is accomplished by generating a sufficiently high-amplified spontaneous\\u000a emission intensity at one Stokes shift in the wavelength from the lasing line to stabilize the latter at the cost of lasing\\u000a efficiency. In

  1. Enhanced Spontaneous Emission Into The Mode Of A Cavity QED System

    E-print Network

    M. L. Terraciano; R. Olson Knell; D. L. Freimund; L. A. Orozco; J. P. Clemens; P. R. Rice

    2007-02-16

    We study the light generated by spontaneous emission into a mode of a cavity QED system under weak excitation of the orthogonally polarized mode. Operating in the intermediate regime of cavity QED with comparable coherent and decoherent coupling constants, we find an enhancement of the emission into the undriven cavity mode by more than a factor of 18.5 over that expected by the solid angle subtended by the mode. A model that incorporates three atomic levels and two polarization modes quantitatively explains the observations.

  2. Advanced Emission Control Development Program.

    SciTech Connect

    Evans, A.P.

    1997-12-31

    Babcock & Wilcox (B&W) is conducting a five-year project aimed at the development of practical, cost-effective strategies for reducing the emissions of hazardous air pollutants (commonly called air toxics) from coal-fired electric utility plants. The need for air toxic emissions controls may arise as the U. S. Environmental Protection Agency proceeds with implementation of Title III of the Clean Air Act Amendment (CAAA) of 1990. Data generated during the program will provide utilities with the technical and economic information necessary to reliably evaluate various air toxics emissions compliance options such as fuel switching, coal cleaning, and flue gas treatment. The development work is being carried out using B&W`s new Clean Environment Development Facility (CEDF) wherein air toxics emissions control strategies can be developed under controlled conditions, and with proven predictability to commercial systems. Tests conducted in the CEDF provide high quality, repeatable, comparable data over a wide range of coal properties, operating conditions, and emissions control systems. Development work to date has concentrated on the capture of mercury, other trace metals, fine particulate, and the inorganic species hydrogen chloride and hydrogen fluoride.

  3. Advanced Emissions Control Development Program

    SciTech Connect

    A. P. Evans

    1998-12-03

    Babcock & Wilcox (B&W) is conducting a five-year project aimed at the development of practical, cost-effective strategies for reducing the emissions of hazardous air pollutants (commonly called air toxics) from coal-fired electric utility plants. The need for air toxic emissions controls may arise as the U. S. Environmental Protection Agency proceeds with implementation of Title III of the Clean Air Act Amendment (CAAA) of 1990. Data generated during the program will provide utilities with the technical and economic information necessary to reliably evaluate various air toxics emissions compliance options such as fuel switching, coal cleaning, and flue gas treatment. The development work is being carried out using B&W?s new Clean Environment Development Facility (CEDF) wherein air toxics emissions control strategies can be developed under controlled conditions, and with proven predictability to commercial systems. Tests conducted in the CEDF provide high quality, repeatable, comparable data over a wide range of coal properties, operating conditions, and emissions control systems. Development work to date has concentrated on the capture of mercury, other trace metals, fine particulate, and the inorganic species hydrogen chloride and hydrogen fluoride.

  4. Advanced Emissions Control Development Program

    SciTech Connect

    M. J. Holmes

    1998-12-03

    McDermott Technology, Inc. (MTI) is conducting a five-year project aimed at the development of practical, cost-effective strategies for reducing the emissions of hazardous air pollutants (commonly called air toxics) from coal-fired electric utility plants. The need for air toxic emissions controls may arise as the U. S. Environmental Protection Agency proceeds with implementation of Title III of the Clean Air Act Amendment (CAAA) of 1990. Data generated during the program will provide utilities with the technical and economic information necessary to reliably evaluate various air toxics emissions compliance options such as fuel switching, coal cleaning, and flue gas treatment. The development work is being carried out using the Clean Environment Development Facility (CEDF) wherein air toxics emissions control strategies can be developed under controlled conditions, and with proven predictability to commercial systems. Tests conducted in the CEDF provide high quality, repeatable, comparable data over a wide range of coal properties, operating conditions, and emissions control systems. Development work to date has concentrated on the capture of mercury, other trace metals, fine particulate, and hydrogen chloride and hydrogen fluoride.

  5. Numerical study of amplified spontaneous emission and lasing in random media

    NASA Astrophysics Data System (ADS)

    Andreasen, Jonathan; Cao, Hui

    2010-12-01

    We simulate the transition from amplified spontaneous emission (ASE) to lasing in random systems with varying degrees of mode overlap. This is accomplished by solving the stochastic Maxwell-Bloch equations with the finite-difference time-domain method. Below lasing threshold, the continuous emission spectra are narrowed by frequency-dependent amplification. Our simulations reproduce the stochastic emission spikes in the spectra. Well-defined peaks, corresponding to the system resonances, emerge at higher pumping and are narrowed by stimulated emission before lasing takes place. Noise tends to distribute pump energy over many modes, resulting in multimode operation. Well above the lasing threshold, the effects of noise lessen and results become similar to those without noise. By comparing systems of different scattering strength, we find that weaker scattering extends the transition region from ASE to lasing, where the effects of noise are most significant.

  6. Charge-carrier concentration and temperature in quantum wells of laser heterostructures under spontaneous-and stimulated-emission conditions

    Microsoft Academic Search

    L. E. Vorob’ev; V. L. Zerova; K. S. Borshchev; Z. N. Sokolova; I. S. Tarasov; G. Belenky

    2008-01-01

    The charge-carrier concentration and the temperature of hot electrons and holes in quantum-well laser nanostructures in the\\u000a regimes of spontaneous and stimulated emission are determined as functions of the current density j, with InGaAs\\/GaAs structures as an example. Under spontaneous-emission conditions, the carrier concentration in the active\\u000a region of a laser structure grows as the current increases, while carrier heating

  7. Molecular hot electroluminescence due to strongly enhanced spontaneous emission rates in a plasmonic nanocavity

    NASA Astrophysics Data System (ADS)

    Chen, Gong; Li, Xiao-Guang; Zhang, Zhen-Yu; Dong, Zhen-Chao

    2015-01-01

    We have recently demonstrated anomalous relaxationless hot electroluminescence from molecules in the tunnel junction of a scanning tunneling microscope [Dong et al., Nat. Photonics, 2010, 4, 50]. In the present paper, based on physically realistic parameters, we aim to unravel the underlying physical mechanism using a multiscale modeling approach that combines classical generalized Mie theory with the quantum master equation. We find that the nanocavity-plasmon-tuned spontaneous emission rate plays a crucial role in shaping the spectral profile. In particular, on resonance, the radiative decay rate can be enhanced by three-to-five orders of magnitude, which enables the radiative process to occur on the lifetime scale of picoseconds and become competitive to the vibrational relaxation. Such a large Purcell effect opens up new emission channels to generate the hot luminescence that arises directly from higher vibronic levels of the molecular excited state. We also stress that the critical role of resonant plasmonic nanocavities in tunneling electron induced molecular luminescence is to enhance the spontaneous radiative decay through plasmon enhanced vacuum fluctuations rather than to generate an efficient plasmon stimulated emission process. This improved understanding has been partly overlooked in previous studies but is believed to be very important for further developments of molecular plasmonics and optoelectronics.

  8. Molecular hot electroluminescence due to strongly enhanced spontaneous emission rates in a plasmonic nanocavity.

    PubMed

    Chen, Gong; Li, Xiao-Guang; Zhang, Zhen-Yu; Dong, Zhen-Chao

    2015-02-14

    We have recently demonstrated anomalous relaxationless hot electroluminescence from molecules in the tunnel junction of a scanning tunneling microscope [Dong et al., Nat. Photonics, 2010, 4, 50]. In the present paper, based on physically realistic parameters, we aim to unravel the underlying physical mechanism using a multiscale modeling approach that combines classical generalized Mie theory with the quantum master equation. We find that the nanocavity-plasmon-tuned spontaneous emission rate plays a crucial role in shaping the spectral profile. In particular, on resonance, the radiative decay rate can be enhanced by three-to-five orders of magnitude, which enables the radiative process to occur on the lifetime scale of picoseconds and become competitive to the vibrational relaxation. Such a large Purcell effect opens up new emission channels to generate the hot luminescence that arises directly from higher vibronic levels of the molecular excited state. We also stress that the critical role of resonant plasmonic nanocavities in tunneling electron induced molecular luminescence is to enhance the spontaneous radiative decay through plasmon enhanced vacuum fluctuations rather than to generate an efficient plasmon stimulated emission process. This improved understanding has been partly overlooked in previous studies but is believed to be very important for further developments of molecular plasmonics and optoelectronics. PMID:25565003

  9. USER'S GUIDE: EMISSION CONTROL TECHNOLOGIES AND EMISSION FACTORS FOR UNPAVED ROAD FUGITIVE EMISSIONS

    EPA Science Inventory

    This document assists control agency personnel in evaluating unpaved road fugitive emissions control plans and helps industry personnel develop effective control strategies for unpaved roads. he brochure describes control techniques for reducing unpaved road emissions and methods...

  10. Spectroscopic properties and amplified spontaneous emission of a new derivative of fluorescein

    NASA Astrophysics Data System (ADS)

    Kana, M. T. H. A.; Al-Shamiri, H. A. S.; Azzouz, I. M.; Elwahy, A. H. M.

    2007-09-01

    The new laser dye, 2-(6-acryloyloxy-3-oxo-3H-xanthen-9-yl)-benzoic acid ethyl ester [AOXBE] has been synthesized. Its chemical structure was confirmed by 1HNMR, IR, MS and elemental analysis. This new dye was covalently bonded with methyl methacrylate (MMA) and 2-hydroxy ethyl-methacrylate (HEMA) copolymer backbone. Its optical properties were experimentally investigated. Amplified spontaneous emission (ASE) and photostability were studied by pumping the dye polymeric sample with a 355 nm (8 ns) pulsed Nd:YAG laser.

  11. Influence of pump-phase fluctuations on entanglement generation using a correlated spontaneous-emission laser

    E-print Network

    Qamar, Shahid; Xiong, Han; Zubairy, M. Suhail

    2007-01-01

    Influence of pump-phase fluctuations on entanglement generation using a correlated spontaneous-emission laser Shahid Qamar,1,* Han Xiong,2 and M. Suhail Zubairy1,2,3,? 1Centre for Quantum Physics, COMSATS Institute of Information Technology..., Islamabad, Pakistan 2Institute for Quantum Studies and Department of Physics, Texas A& M University, College Station, Texas 77843, USA 3Texas A&M University at Qatar, Education City, P.O. Box 23874, Doha, Qatar #1;Received 12 July 2006; published 6 June...

  12. Long-lived quantum coherence of two-level spontaneous emission models within structured environments

    NASA Astrophysics Data System (ADS)

    Zhang, Ping; You, Bo; Cen, Li-Xiang

    2013-09-01

    We investigate the long-lived quantum coherence of two-level spontaneous emission models within structured environments. The population of the system under the asymptotic non-Markovian dynamics is linked to the spectral density of the reservoir through a general functional relation between them. We figure out explicitly the preservation of quantum coherence, via notions of entanglement and quantum discord, in connection with the spectral parameters of Ohmic class reservoirs and then show how to achieve them optimally. We expect these results to contribute towards reservoir engineering with the aim of enhancing stationary quantum coherence in noisy environments.

  13. Trace element emissions from spontaneous combustion of gob piles in coal mines, Shanxi, China

    USGS Publications Warehouse

    Zhao, Y.; Zhang, J.; Chou, C.-L.; Li, Y.; Wang, Z.; Ge, Y.; Zheng, C.

    2008-01-01

    The emissions of potentially hazardous trace elements from spontaneous combustion of gob piles from coal mining in Shanxi Province, China, have been studied. More than ninety samples of solid waste from gob piles in Shanxi were collected and the contents of twenty potentially hazardous trace elements (Be, F, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Sn, Sb, Hg, Tl, Pb, Th, and U) in these samples were determined. Trace element contents in solid waste samples showed wide ranges. As compared with the upper continental crust, the solid waste samples are significantly enriched in Se (20x) and Tl (12x) and are moderately enriched in F, As, Mo, Sn, Sb, Hg, Th, and U (2-5x). The solid waste samples are depleted in V, Cr, Mn, Co, Ni, Cu, and Zn. The solid waste samples are enriched in F, V, Mn, Cr, Co, Ni, Cu, Zn, Sb, Th, and U as compared with the Shanxi coals. Most trace elements are higher in the clinker than in the unburnt solid waste except F, Sn, and Hg. Trace element abundances are related to the ash content and composition of the samples. The content of F is negatively correlated with the ash content, while Pb is positively correlated with the ash. The concentrations of As, Mn, Zn, and Cd are highly positively correlated with Fe2O3 in the solid waste. The As content increases with increasing sulfur content in the solid waste. The trace element emissions are calculated for mass balance. The emission factors of trace elements during the spontaneous combustion of the gobs are determined and the trace element concentrations in the flue gas from the spontaneous combustion of solid waste are calculated. More than a half of F, Se, Hg and Pb are released to the atmosphere during spontaneous combustion. Some trace element concentrations in flue gas are higher than the national emission standards. Thus, gob piles from coal mining pose a serious environmental problem. ?? 2007 Elsevier B.V. All rights reserved.

  14. Spontaneous emission and collection efficiency enhancement of single emitters in diamond via plasmonic cavities and gratings

    E-print Network

    Jennifer T. Choy; Irfan Bulu; Birgit J. M. Hausmann; Erika Janitz; I-Chun Huang; Marko Lon?ar

    2013-08-02

    We demonstrate an approach, based on plasmonic apertures and gratings, to enhance the radiative decay rate of single NV centers in diamond, while simultaneously improving their collection efficiency. Our structures are based on metallic resonators formed by surrounding sub-wavelength diamond nanoposts with a silver film, which can enhance the spontaneous emission rate of an embedded NV center. However, the collection efficiency of emitted photons remains low due to losses to surface plasmons and reflections at the diamond-air interface. In this work, we mitigate photon losses into these channels by incorporating grating structures into the plasmonic cavity system.

  15. Influence of pump-phase fluctuations on entanglement generation using a correlated spontaneous-emission laser 

    E-print Network

    Qamar, Shahid; Xiong, Han; Zubairy, M. Suhail

    2007-01-01

    Influence of pump-phase fluctuations on entanglement generation using a correlated spontaneous-emission laser Shahid Qamar,1,* Han Xiong,2 and M. Suhail Zubairy1,2,3,? 1Centre for Quantum Physics, COMSATS Institute of Information Technology..., Islamabad, Pakistan 2Institute for Quantum Studies and Department of Physics, Texas A& M University, College Station, Texas 77843, USA 3Texas A&M University at Qatar, Education City, P.O. Box 23874, Doha, Qatar #1;Received 12 July 2006; published 6 June...

  16. Concentration effects on spontaneous and amplified emission in benzo[c]fluorenes.

    PubMed

    Kazlauskas, Karolis; Kreiza, Gediminas; Radiunas, Edvinas; Adom?nas, Povilas; Adom?nien?, Ona; Karpavi?ius, Karolis; Bucevi?ius, Jonas; Jankauskas, Vygintas; Jurš?nas, Saulius

    2015-05-01

    Deep-blue-emitting benzo[c]fluorene-cored compounds featuring twisted peripheral moieties for suppressed concentration quenching of emission were synthesized and investigated as potential materials for light amplification. This detailed study of the effect of concentration on the spontaneous and stimulated emission, excited-state lifetime and susceptibility to form aggregates obtained for different benzofluorenes, has enabled the understanding of the concentration dependence of the amplified spontaneous emission (ASE) threshold and revealed the optimal concentration for the lowest threshold. The weak concentration quenching accompanied by high fluorescence quantum yield (>40%) and radiative decay rate (>5 × 10(8) s(-1)) have enabled the attainment of the lowest ASE threshold in the neat amorphous film of benzofluorene bearing dihexylfluorenyl peripheral moieties. Aggregate formation was found to negligibly affect the emission efficiency of the benzofluorene films; however, it drastically increased ASE threshold via the enhanced scattering of directional stimulated emission, and thereby implied the necessity to utilize homogeneous glassy films as the lasing medium. Although the bulky dihexylfluorenyl groups at the periphery ensured the formation of glassy benzofluorene films with the ASE threshold as low as 900 W cm(-2) (under nanosecond excitation), they adversely affected carrier drift mobility, which implied a tradeoff between ASE and charge transport properties for the lasing materials utilized in the neat form. Such a low ASE threshold attained in air is among the lowest reported for solution-processed neat films. The low threshold and enhanced photostability of benzofluorenes against fluorene compounds in air show great potential for benzofluorene-cored molecular glasses as active media for lasing applications. PMID:25912324

  17. Nonexponential decay of spontaneous emission from an ensemble of molecules in photonic crystals

    NASA Astrophysics Data System (ADS)

    Vallée, R. A. L.; Baert, K.; Kolaric, B.; van der Auweraer, M.; Clays, K.

    2007-07-01

    Photonic crystals (PCs) with relatively low dielectric contrast (i.e., with pseudogaps) have significant influence on the fluorescence decay of internal emitters. Fluorescence decays of ensembles of dye molecules measured at different positions in the PCs exhibit a nonexponential behavior, which is best fitted by a continuous distribution of decay rates. The most frequent decay rates of these distributions are smaller and their widths are narrower in a PC with a pseudogap acting in the emission range of the emitters than in a PC having the pseudogap out of this range. These experimental results have been well accounted for by calculations of the local density of states and rate constant for spontaneous emission.

  18. Investigation of the spontaneous emission rate of perylene dye molecules encapsulated into three-dimensional nanofibers via FLIM method

    NASA Astrophysics Data System (ADS)

    Acikgoz, Sabriye; Demir, Mustafa M.; Yapasan, Ece; Kiraz, Alper; Unal, Ahmet A.; Inci, M. Naci

    2014-09-01

    The decay dynamics of perylene dye molecules encapsulated in polymer nanofibers produced by electrospinning of polymethyl methacrylate are investigated using a confocal fluorescence lifetime imaging microscopy technique. Time-resolved experiments show that the fluorescence lifetime of perylene dye molecules is enhanced when the dye molecules are encapsulated in a three-dimensional photonic environment. It is hard to produce a sustainable host with exactly the same dimensions all the time during fabrication to accommodate dye molecules for enhancement of spontaneous emission rate. The electrospinning method allows us to have a control over fiber diameter. It is observed that the wavelength of monomer excitation of perylene dye molecules is too short to cause enhancement within nanofiber photonic environment of 330 nm diameters. However, when these nanofibers are doped with more concentrated perylene, in addition to monomer excitation, an excimer excitation is generated. This causes observation of the Purcell effect in the three-dimensional nanocylindrical photonic fiber geometry.

  19. Brillouin optical correlation domain analysis with 4 millimeter resolution based on amplified spontaneous emission.

    PubMed

    Cohen, Raphael; London, Yosef; Antman, Yair; Zadok, Avi

    2014-05-19

    A new technique for Brillouin scattering-based, distributed fiber-optic measurements of temperature and strain is proposed, analyzed, simulated, and demonstrated. Broadband Brillouin pump and signal waves are drawn from the filtered amplified spontaneous emission of an erbium-doped fiber amplifier, providing high spatial resolution. The reconstruction of the position-dependent Brillouin gain spectra along 5 cm of a silica single-mode fiber under test, with a spatial resolution of 4 mm, is experimentally demonstrated using a 25 GHz-wide amplified spontaneous emission source. A 4 mm-long localized hot spot is identified by the measurements. The uncertainty in the reconstruction of the local Brillouin frequency shift is ± 1.5 MHz. The single correlation peak between the pump and signal is scanned along a fiber under test using a mechanical variable delay line. The analysis of the expected spatial resolution and the measurement signal-to-noise ratio is provided. The measurement principle is supported by numerical simulations of the stimulated acoustic field as a function of position and time. Unlike most other Brillouin optical correlation domain analysis configurations, the proposed scheme is not restricted by the bandwidth of available electro-optic modulators, microwave synthesizers, or pattern generators. Resolution is scalable to less than one millimeter in highly nonlinear media. PMID:24921326

  20. On the spontaneous emission of electromagnetic radiation in the CSL model

    NASA Astrophysics Data System (ADS)

    Donadi, Sandro; Deckert, Dirk-André; Bassi, Angelo

    2014-01-01

    Spontaneous photon emission in the Continuous Spontaneous Localization (CSL) model is studied one more time. In the CSL model each particle interacts with a noise field that induces the collapse of its wave function. As a consequence of this interaction, when the particle is electrically charged, it radiates. As discussed in Adler (2013) the formula for the emission rate, to first perturbative order, contains two terms: one is proportional to the Fourier component of the noise field at the same frequency as that of the emitted photon and one is proportional to the zero Fourier component of the noise field. As discussed in previous works, this second term seems unphysical. In Adler (2013) it was shown that the unphysical term disappears when the noise is confined to a bounded region and the final particle's state is a wave packet. Here we investigate the origin of this unphysical term and why it vanishes according to the previous prescription. We will see that perturbation theory is formally not valid in the large time limit since the effect of the noise accumulates continuously in time. Therefore either one performs an exact calculation (or at least in some way includes higher order terms) as we do here, or one finds a way to make a perturbative calculation meaningful, e.g., by confining the system as in Adler (2013).

  1. Control emissions with flare efficiency

    SciTech Connect

    Romano, R.R.

    1983-10-01

    The combustion of gas in flare towers is an efficient and effective way to control hydrocarbon emissions from many hydrocarbon processing plant processes, according to recent studies sponsored by the Chemical Manufacturers Assn. (CMA) and the Environmental Protection Agency. The study tested flares under 34 different operating conditions. Test variables included Btu content of the flare gas, flare gas flow rates, steam flow rates and air flow rates. The study found that when flares were operated under typical industrial operating conditions combustion efficiencies exceeded 98 percent. Excess steam, or flaring high volumes of low heating value gases, may contribute to lower combustion efficiencies. It also showed that smoking flares do not necessarily indicate inefficient hydrocarbon combustion. Samples of air over the flare were taken using a specially constructed 27-foot sample probe suspended over the flare flame. The samples were analyzed to determine the concentrations of carbon dioxide, carbon monoxide, total hydrocarbons, sulfur dioxide, oxides of nitrogen and oxygen. CMA sponsored the study to learn exactly how effective flares are for pollution control and determine if they can be more widely used as an effective, cost-efficient pollution control alternative. Savings associated with using flares instead of incinerators to control emissions may be $500,000 to $10 million per facility.

  2. Electrically Controllable Spontaneous Magnetism in Nanoscale Mixed Phase Multiferroics

    Microsoft Academic Search

    Q. He; Y. H. Chu; J. T. Heron; S. Y. Yang; C. H. Wang; C. Y. Kuo; H. J. Lin; P. Yu; C. W. Liang; R. J. Zeches; C. T. Chen; E. Arenholz; A. Scholl; R. Ramesh

    2010-01-01

    The emergence of enhanced spontaneous magnetic moments in self-assembled, epitaxial nanostructures of tetragonal (T-phase) and rhombohedral phases (R-phase) of the multiferroic BiFeO system is demonstrated. X-ray magnetic circular dichroism based photoemission electron microscopy (PEEM) was applied to investigate the local nature of this magnetism. We find that the spontaneous magnetization of the R-phase is significantly enhanced above the canted antiferromagnetic

  3. Generalized theory and simulation of spontaneous and super-radiant emissions in electron devices and free-electron lasers.

    PubMed

    Pinhasi, Y; Lurie, Yu

    2002-02-01

    A unified formulation of spontaneous (shot-noise) and super-radiant emissions in electron devices is presented. We consider an electron beam with an arbitrary temporal current modulation propagating through the interaction region of the electronic device. The total electromagnetic field is presented as a stochastic process and expanded in terms of transverse eigenmodes of the medium (free space or waveguide), in which the field is excited and propagates. Using the waveguide excitation equations, formulated in the frequency domain, an analytical expression for the power spectral density of the electromagnetic radiation is derived. The spectrum of the excited radiation is shown to be composed of two terms, which are the spontaneous and super-radiant emissions. For a continuous, unmodulated beam, the shot noise produces only incoherent spontaneous emission of a power proportional to the flux eI(0) (DC current) of the particles in the electron beam. When the beam is modulated or prebunched, a partially coherent super-radiant emission is also produced with power proportional to the current spectrum /I(omega)/(2). Based on a three-dimensional model, a numerical particle simulation code was developed. A set of coupled-mode excitation equations in the frequency domain are solved self-consistently with the equations of particles motion. The simulation considers random distributions of density and energy in the electron beam and takes into account the statistical and spectral features of the excited radiation. At present, the code can simulate free-electron lasers (FELs) operation in various modes: spontaneous and self-amplified spontaneous emission, super-radiance and stimulated emission, in the linear and nonlinear Compton or Raman regimes. We employed the code to demonstrate spontaneous and super-radiant emission excited when a prebunched electron beam passes through a wiggler of an FEL. PMID:11863669

  4. Exhaust emission control and diagnostics

    DOEpatents

    Mazur, Christopher John; Upadhyay, Devesh

    2006-11-14

    A diesel engine emission control system uses an upstream oxidation catalyst and a downstream SCR catalyst to reduce NOx in a lean exhaust gas environment. The engine and upstream oxidation catalyst are configured to provide approximately a 1:1 ratio of NO to NO2 entering the downstream catalyst. In this way, the downstream catalyst is insensitive to sulfur contamination, and also has improved overall catalyst NOx conversion efficiency. Degradation of the system is determined when the ratio provided is no longer near the desired 1:1 ratio. This condition is detected using measurements of engine operating conditions such as from a NOx sensor located downstream of the catalysts. Finally, control action to adjust an injected amount of reductant in the exhaust gas based on the actual NO to NO2 ratio upstream of the SCR catalyst and downstream of the oxidation catalyst.

  5. Spontaneous Emission Between - and Para-Levels of Water-Ion H_2O^+

    NASA Astrophysics Data System (ADS)

    Tanaka, Keiichi; Harada, Kensuke; Nanbu, Shinkoh; Oka, Takeshi

    2012-06-01

    Nuclear spin conversion interaction of water ion, H_2O^+, has been studied to derive spontaneous emission lifetime between ortho- and para-levels. H_2O^+ is a radical ion with the ^2B_1 electronic ground state. Its off-diagonal electron spin-nuclear spin interaction term, Tab(S_a? I_b + S_b? I_a), connects para and ortho levels, because ? I = I_1 - I_2 has nonvanishing matrix elements between I = 0 and 1. The mixing by this term with Tab = 72 MHz predicted by ab initio theory in the MRD-CI/Bk level, is many orders of magnitude larger than for closed shell molecules because of the large magnetic interaction due to the un-paired electron. Using the molecular constants reported by Mürtz et al. by FIR-LMR, we searched for ortho and para coupling channels below 1000 cm-1 with accidental near degeneracy between para and ortho levels. For example, hyperfine components of the 42,2(ortho) and 33,0(para) levels mix by 1.2 × 10-3 due to their near degeneracy (? E = 0.417 cm-1), and give the ortho-para spontaneous emission lifetime of about 0.63 year. The most significant low lying 10,1(para) and 11,1(ortho) levels, on the contrary, mix only by 8.7 × 10-5 because of their large separation (? E = 16.267 cm-1) and give the spontaneous emission lifetime from 10,1(para) to 00,0(ortho) of about 100 year.These results qualitatively help to understand the observed high ortho- to para- H_2O^+ ratio of 4.8 ± 0.5 toward Sgr B2 but they are too slow to compete with the conversion by collision unless the number density of the region is very low (n ˜1 cm-3) or radiative temperature is very high (T_r > 100 K). M. Staikova, B. Engels, M. Peric, and S.D. Peyerimhoff, Mol. Phys. 80, 1485 (1993) P. Mürtz, L.R. Zink, K.M. Evenson, and J.M. Brown J. Chem. Phys. 109, 9744 (1998). LP. Schilke, et al., A&A 521, L11 (2010).

  6. PARTICULATE EMISSION MEASUREMENTS FROM CONTROLLED CONSTRUCTION ACTIVITIES

    EPA Science Inventory

    The report summarized the results of field testing of the effectiveness of control measures for sources of fugitive particulate emissions found at construction sites. The effectiveness of watering temporary, unpaved travel surfaces on emissions of particulate matter with aerodyna...

  7. Photo-physical properties and amplified spontaneous emission of a new derivative of fluorescein

    NASA Astrophysics Data System (ADS)

    Al-Shamiri, Hamdan A. S.; Kana, Maram T. H. Abou; Azzouz, I. M.; Elwahy, Ahmed H. M.

    2010-04-01

    The synthesis of new high-performance dyes and the implementation of new ways of incorporating the organic molecules into the solid host matrices have produced a great deal of activity in the field of solid-state dye lasers. In this article, the new laser dye, 2-(6-allyl-3-oxo-3H-xanthen-9-yl)-benzoic acid ethyl ester [AXBE] has been synthesized, and its chemical structure was confirmed by 1H NMR, 13C NMR, IR and elemental analysis. This new dye was covalently bonded with methyl methacrylate (MMA) and 2-hydroxy ethyl methacrylate (HEMA) copolymer backbone and evaluated as the active medium of the solid-state laser dye. Its optical properties were experimentally investigated. Amplified spontaneous emission (ASE) and photostability were studied by pumping the dye sample with 355 nm (8 ns) pulsed Nd-YAG laser.

  8. Enhancing mammalian hearing by a balancing between spontaneous otoacoustic emissions and spatial coupling

    NASA Astrophysics Data System (ADS)

    Liu, Zonghua; Li, Baowen; Lai, Ying-Cheng

    2012-04-01

    Nonlinear dynamics has provided significant insights into the origin of frequency discrimination and signal amplification underlying mammalian hearing. Existing signal amplification models, however, tend to ignore two basic known aspects of the hearing: spontaneous otoacoustic emissions (SOAEs) and intrinsic dynamical coupling in the cochlea. We construct and study a class of coupled-oscillator models to remedy this deficiency. Our analysis and computations reveal that the interplay and balance between the two aspects can naturally explain the phenomena of frequency discrimination and signal amplification and, more strikingly, the origin of hearing loss, all at a quantitative level. In the presence of SOAEs, there exists a critical coupling threshold below which hearing loss can occur, suggesting enhancement of coupling as a potentially effective therapeutic strategy to restore or even significantly enhance hearing.

  9. Start-up noise in 3-D self-amplified spontaneous emission

    SciTech Connect

    Kim, Kwang-Je

    1996-08-01

    The Self-Amplified-Spontaneous Emission (SASE) is receiving a renewed interest recently in connection with the proposal to build x-ray FEL facilities. A consistent theory of how the initial incoherent undulator radiation develops into an exponentially growing coherent signal was derived in 1-D case previously. How the theory could be extended to a 3-D case was also explained previously. In the case of the parallel electron beam, the problem was explicitly solved previously. In particular, the equivalent noise power was identified as the undulator radiation in one gain length. In this paper, we study how the result should be modified when the electrons` angular divergence is taken into account. We find that the equivalent noise power is the portion of the undulator power within the coherent phase space area, a result that should have been expected.

  10. Three-dimensional analysis of harmonic generation in self-amplified spontaneous emission.

    SciTech Connect

    Huang, Z.; Kim, K.-J.

    1999-09-01

    In a high-gain free-electron laser, strong bunching at the fundamental wavelength can drive substantial harmonic bunching and sizable power levels at the harmonic frequencies. In this paper, we investigate the three-dimensional evolution of the harmonic fields based on the coupled Maxwell-Vlasov equations that take into account the nonlinear harmonic interaction. Each harmonic field is the sum of a self-amplified term and a term driven by the nonlinear harmonic interaction. In the exponential gain regime, the growth rate of the dominant nonlinear term is much faster than that of the self-amplified harmonic field. As a result, the gain length and the transverse profile of the first few harmonics are completely determined by those of the fundamental. A percentage of the fundamental power level is found at the third harmonic frequency right before saturation for the current self-amplified spontaneous emission projects.

  11. Low threshold amplified spontaneous emission from dye-doped DNA biopolymer

    NASA Astrophysics Data System (ADS)

    Hung, Yu-Chueh; Su, Che-Hsuan; Huang, Hsien-Wen

    2012-06-01

    In this study, we investigate the amplified spontaneous emission (ASE) properties and conduct a comparative study for two kinds of dye-doped deoxyribonucleic acid (DNA) biopolymers. The system consists of optical films made of DNA modified by two types of surfactants and doped with a common laser dye rhodamine 6G (Rh6G). The ASE properties of the optical films were characterized by a pulsed Nd:YAG laser. The results show that low threshold of DNA biopolymer can be achieved by the employment of suitable surfactant in the system, resulting from an efficient energy transfer process. Coupled with the fluorescence enhancement exhibited in DNA, this effect can further advance biopolymers toward highly efficient media for lasing applications and organic solid-state lasers.

  12. Temporal phase mask encrypted optical steganography carried by amplified spontaneous emission noise.

    PubMed

    Wu, Ben; Wang, Zhenxing; Shastri, Bhavin J; Chang, Matthew P; Frost, Nicholas A; Prucnal, Paul R

    2014-01-13

    A temporal phase mask encryption method is proposed and experimentally demonstrated to improve the security of the stealth channel in an optical steganography system. The stealth channel is protected in two levels. In the first level, the data is carried by amplified spontaneous emission (ASE) noise, which cannot be detected in either the time domain or spectral domain. In the second level, even if the eavesdropper suspects the existence of the stealth channel, each data bit is covered by a fast changing phase mask. The phase mask code is always combined with the wide band noise from ASE. Without knowing the right phase mask code to recover the stealth data, the eavesdropper can only receive the noise like signal with randomized phase. PMID:24515055

  13. Systematic study of spontaneous emission in a two-dimensional arbitrary inhomogeneous environment

    SciTech Connect

    Qiao Pengfei; Sha, Wei E. I.; Choy, Wallace C. H.; Chew, Weng Cho [Department of Electrical and Electronic Engineering, University of Hong Kong, Pokfulam Road (Hong Kong); Department of Electrical and Electronic Engineering, University of Hong Kong, Pokfulam Road (Hong Kong) and Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urban, Illinois 61820 (United States)

    2011-04-15

    The spontaneous emission (SE) of the excited atoms in a two-dimensional (2D) arbitrary inhomogeneous environment has been systematically studied. The local density of states, which determines the radiation dynamics of a point source (for 3D) or a line source (for 2D), in particular, the SE rate, is represented by the electric dyadic Green's function. The numerical solution of the electric Green's tensor has been accurately obtained with the finite-difference frequency-domain method with the proper approximations of the monopole and dipole sources. The SE of atoms in photonic crystal and plasmonic metal plates has been comprehensively and comparatively investigated. For both the photonic crystal and plasmonic plates systems, the SEs depend on their respective dispersion relations and could be modified by the finite-structure or finite-size effects. This work is important for SE engineering and the optimized design of optoelectronic devices.

  14. Inhibition and enhancement of the spontaneous emission of quantum dots in micropillar cavities with radial-distributed Bragg reflectors.

    PubMed

    Jakubczyk, Tomasz; Franke, Helena; Smole?ski, Tomasz; Sciesiek, Maciej; Pacuski, Wojciech; Golnik, Andrzej; Schmidt-Grund, Rüdiger; Grundmann, Marius; Kruse, Carsten; Hommel, Detlef; Kossacki, Piotr

    2014-10-28

    We present a micropillar cavity where nondesired radial emission is inhibited. The photonic confinement in such a structure is improved by implementation of an additional concentric radial-distributed Bragg reflector. Such a reflector increases the reflectivity in all directions perpendicular to the micropillar axis from a typical value of 15-31% to above 98%. An inhibition of the spontaneous emission of off-resonant excitonic states of quantum dots embedded in the microcavity is revealed by time-resolved experiments. It proves a decreased density of photonic states related to unwanted radial leakage of photons out of the micropillar. For on-resonance conditions, we find that the dot emission rate is increased, evidencing the Purcell enhancement of spontaneous emission. The proposed design can increase the efficiency of single-photon sources and bring to micropillar cavities the functionalities based on lengthened decay times. PMID:25181393

  15. CONTROL OF COPPER SMELTER FUGITIVE EMISSIONS

    EPA Science Inventory

    This report deals with fugitive emissions from copper smelting and with related emission control measures. The study involved evaluation of the controls now used in the copper smelting industry and development of suggestions for alternative control devices and practices. A brief ...

  16. Measurement of spontaneous-emission enhancement near the one-dimensional photonic band edge of semiconductor heterostructures

    Microsoft Academic Search

    Michael D. Tocci; Michael Scalora; Mark J. Bloemer; Jonathan P. Dowling; Charles M. Bowden

    1996-01-01

    We present results of an experimental investigation into alteration of the spontaneous emission spectrum of GaAs from within one-dimensional photonic band gap (PBG) structures. The PBG samples are multilayer AlAs\\/Al0.2Ga0.8As\\/GaAs p-i-n light-emitting diodes, with layers arranged as a distributed Bragg reflector. The emission spectra normal to the layers are measured, and we use a simple method to model the power

  17. EFFECTS OF INSTILLED EMISSION PARTICULATE MATTER ON ELECTROCARDIOGRAPHIC INDICES AND HEART RATE VARIABILITY (HRV) IN SPONTANEOUSLY HYPERTENSIVE RATS

    EPA Science Inventory

    EFFECTS OF INSTILLED EMISSION PARTICULATE MATTER (EPM) ON ELECTROCARDIOGRAPHIC INDICES AND HEART RATE VARIABILITY (HRV) IN SPONTANEOUSLY HYPERTENSIVE (SH) RATS. L.B. Wichers1, J.P. Nolan2, W.H. Rowan2, M.J. Campen3, T.P. Jenkins4, D.L. Costa2, and W.P. Watkinson2. 1UNC SPH, Chap...

  18. Measurement of spontaneous emission from a two-dimensional photonic band gap defined microcavity at near-infrared wavelengths

    Microsoft Academic Search

    R. K. Lee; O. J. Painter; B. D'Urso; A. Scherer; A. Yariv

    1999-01-01

    An active, photonic band gap-based microcavity emitter in the near infrared is demonstrated. We present direct measurement of the spontaneous emission power and spectrum from a microcavity formed using a two-dimensional photonic band gap structure in a half wavelength thick slab waveguide. The appearance of cavity resonance peaks in the spectrum correspond to the photonic band gap energy. For detuned

  19. The virtual-photon effects in spontaneous emission from an atom embedded in a photonic band gap structure

    Microsoft Academic Search

    Zhengdong Liu; Y. Lin; Shiyao Zhu; K. Shang; Liang Zeng

    1999-01-01

    In a three-level atom embedded in a photonic band gap structure, the spontaneous emission is studied both with and without rotating-wave approximation. The virtual-photon-localized field is found, which causes a greater population of the atom trapped in its upper states.

  20. Measurement of spontaneous emission from a two-dimensional photonic band gap defined microcavity at near-infrared wavelengths

    Microsoft Academic Search

    R. K. Lee; O. J. Painter; B. D'Urso; A. Scherer; A. Yariv

    An active, photonic band gap-based microcavity emitter in the near infrared is demonstrated. We present direct measurement of the spontaneous emission power and spectrum from a microcavity formed using a two-dimensional photonic band gap structure in a half wavelength thick slab waveguide. The appearance of cavity resonance peaks in the spectrum correspond to the photonic band gap energy. For detuned

  1. Dendritic Control of Spontaneous Bursting in Cerebellar Purkinje Cells

    Microsoft Academic Search

    Mary D. Womack; Kamran Khodakhah

    2004-01-01

    We investigated the mechanisms that contribute to spontaneous regular bursting in adult Purkinje neurons in acutely prepared cerebel- lar slices. Bursts consisted of 3-20 spikes and showed a stereotypic waveform. Each burst developed with an increase in firing rate and was terminated by a more rapid increase in firing rate and a decrease in spike height. Whole-cell current-clamp recordings showed

  2. Reducing Spontaneous Emission in Circuit Quantum Electrodynamics by a Combined Readout/Filter Technique

    E-print Network

    Nicholas T. Bronn; Easwar Magesan; Nicholas A. Masluk; Jerry M. Chow; Jay M. Gambetta; Matthias Steffen

    2015-04-16

    Physical implementations of qubits can be extremely sensitive to environmental coupling, which can result in decoherence. While efforts are made for protection, coupling to the environment is necessary to measure and manipulate the state of the qubit. As such, the goal of having long qubit energy relaxation times is in competition with that of achieving high-fidelity qubit control and measurement. Here we propose a method that integrates filtering techniques for preserving superconducting qubit lifetimes together with the dispersive coupling of the qubit to a microwave resonator for control and measurement. The result is a compact circuit that protects qubits from spontaneous loss to the environment, while also retaining the ability to perform fast, high-fidelity readout. Importantly, we show the device operates in a regime that is attainable with current experimental parameters and provide a specific example for superconducting qubits in circuit quantum electrodynamics.

  3. Amplified spontaneous emission from a microtube cavity with whispering gallery modes

    NASA Astrophysics Data System (ADS)

    Rakovich, Y. P.; Balakrishnan, S.; Gun'ko, Y.; Perova, T. S.; Moore, A.; Donegan, J. F.

    2007-05-01

    We present a detailed study of the photonic modes in microtube cavity of ~ 7-8 ?m outer diameter that can act as micron-scale optical cylindrical resonator. We demonstrate a new route to the fabrication of individual microtubes with the maximum length of 200 ?m, using a vacuum assisted wetting and filtration through a microchannel glass matrix. The microtubes were studied using micro-photoluminescence spectroscopy and luminescence lifetime imaging confocal microscopy. In the emission spectra of the microresonators we find periodic very narrow peaks corresponding to the whispering gallery modes of two orthogonal polarizations with quality factors upto 3200 at room temperature. In order to identify the peaks in the observed mode structure, we have adopted the boundary-value solution to the problem of scattering of electromagnetic waves by a dielectric micro-cylinder. A strong enhancement in photoluminescence decay rates at high excitation power suggest the occurrence of amplified spontaneous emission from a single microtube. The evanescent field in these photonic structures extends a couple of micrometers into the surroundings providing the possibility for efficient coupling to an external photonic device.

  4. Spontaneous emission enhancement in a microtube cavity with highly confined optical modes

    NASA Astrophysics Data System (ADS)

    Rakovich, Y. P.; Balakrishnan, S.; Gun'ko, Y.; Perova, T. S.; Moore, A.; Donegan, J. F.

    2007-06-01

    A detailed study of the photonic modes in microtube cavity of ~ 7-8 ?m outer diameter is presented. We demonstrate a new route to the fabrication of individual microtubes with the maximum length of 200 ?m, using a vacuum assisted wetting and filtration through a microchannel glass matrix. The microtubes were studied using micro-photoluminescence spectroscopy and luminescence lifetime imaging confocal microscopy. In the emission spectra of the microresonators we find periodic very narrow peaks corresponding to the whispering gallery modes of two orthogonal polarizations with quality factors upto 3200 at room temperature. In order to identify the peaks in the observed mode structure, we have adopted the boundary-value solution to the problem of scattering of electromagnetic waves by a dielectric microcylinder. A strong enhancement in photoluminescence decay rates at high excitation power suggest the occurrence of amplified spontaneous emission from a single microtube. The evanescent field in these photonic structures extends a couple of micrometers into the surroundings providing the possibility for efficient coupling to an external photonic device.

  5. Spontaneous emission inhibition of telecom-band quantum disks inside single nanowire on different substrates

    E-print Network

    Birowosuto, M D; Yokoo, A; Takiguchi, M; Notomi, M

    2014-01-01

    We investigate the inhibited spontaneous emission of telecom-band InAs quantum disks (Qdisks) in InP nanowires (NWs). We have evaluated how the inhibition is affected by different disk diameter and thickness. We also compared the inhibition in standing InP NWs and those NWs laying on silica (SiO2), and silicon (Si) substrates. We found that the inhibition is altered when we put the NW on the high-refractive index materials of Si. Experimentally, the inhibition factor $\\zeta$ of the Qdisk emission at 1,500 nm decreases from 4.6 to 2.5 for NW on SiO2 and Si substrates, respectively. Those inhibitions are even much smaller than that of 6.4 of the standing NW. The inhibition factors well agree with those calculated from the coupling of the Qdisk to the fundamental guided mode and the continuum of radiative modes. Our observation can be useful for the integration of the NW as light sources in the photonic nanodevices.

  6. Prolonged spontaneous emission and dephasing of localized excitons in air-bridged carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Sarpkaya, Ibrahim; Zhang, Zhengyi; Walden-Newman, William; Wang, Xuesi; Hone, James; Wong, Chee W.; Strauf, Stefan

    2013-07-01

    The bright exciton emission of carbon nanotubes is appealing for optoelectronic devices and fundamental studies of light-matter interaction in one-dimensional nanostructures. However, to date, the photophysics of excitons in carbon nanotubes is largely affected by extrinsic effects. Here we perform time-resolved photoluminescence measurements over 14 orders of magnitude for ultra-clean carbon nanotubes bridging an air gap over pillar posts. Our measurements demonstrate a new regime of intrinsic exciton photophysics with prolonged spontaneous emission times up to T1=18?ns, about two orders of magnitude better than prior measurements and in agreement with values hypothesized by theorists about a decade ago. Furthermore, we establish for the first time exciton decoherence times of individual nanotubes in the time domain and find fourfold prolonged values up to T2=2.1?ps compared with ensemble measurements. These first observations motivate new discussions about the magnitude of the intrinsic dephasing mechanism while the prolonged exciton dynamics is promising for applications.

  7. Prolonged spontaneous emission and dephasing of localized excitons in air-bridged carbon nanotubes.

    PubMed

    Sarpkaya, Ibrahim; Zhang, Zhengyi; Walden-Newman, William; Wang, Xuesi; Hone, James; Wong, Chee W; Strauf, Stefan

    2013-01-01

    The bright exciton emission of carbon nanotubes is appealing for optoelectronic devices and fundamental studies of light-matter interaction in one-dimensional nanostructures. However, to date, the photophysics of excitons in carbon nanotubes is largely affected by extrinsic effects. Here we perform time-resolved photoluminescence measurements over 14 orders of magnitude for ultra-clean carbon nanotubes bridging an air gap over pillar posts. Our measurements demonstrate a new regime of intrinsic exciton photophysics with prolonged spontaneous emission times up to T1=18 ns, about two orders of magnitude better than prior measurements and in agreement with values hypothesized by theorists about a decade ago. Furthermore, we establish for the first time exciton decoherence times of individual nanotubes in the time domain and find fourfold prolonged values up to T2=2.1 ps compared with ensemble measurements. These first observations motivate new discussions about the magnitude of the intrinsic dephasing mechanism while the prolonged exciton dynamics is promising for applications. PMID:23845935

  8. Loss of the tectorial membrane protein CEACAM16 enhances spontaneous, stimulus-frequency, and transiently evoked otoacoustic emissions.

    PubMed

    Cheatham, Mary Ann; Goodyear, Richard J; Homma, Kazuaki; Legan, P Kevin; Korchagina, Julia; Naskar, Souvik; Siegel, Jonathan H; Dallos, Peter; Zheng, Jing; Richardson, Guy P

    2014-07-30

    ?-Tectorin (TECTA), ?-tectorin (TECTB), and carcinoembryonic antigen-related cell adhesion molecule 16 (CEACAM) are secreted glycoproteins that are present in the tectorial membrane (TM), an extracellular structure overlying the hearing organ of the inner ear, the organ of Corti. Previous studies have shown that TECTA and TECTB are both required for formation of the striated-sheet matrix within which collagen fibrils of the TM are imbedded and that CEACAM16 interacts with TECTA. To learn more about the structural and functional significance of CEACAM16, we created a Ceacam16-null mutant mouse. In the absence of CEACAM16, TECTB levels are reduced, a clearly defined striated-sheet matrix does not develop, and Hensen's stripe, a prominent feature in the basal two-thirds of the TM in WT mice, is absent. CEACAM16 is also shown to interact with TECTB, indicating that it may stabilize interactions between TECTA and TECTB. Although brain-stem evoked responses and distortion product otoacoustic emissions are, for most frequencies, normal in young mice lacking CEACAM16, stimulus-frequency and transiently evoked emissions are larger. We also observed spontaneous otoacoustic emissions (SOAEs) in 70% of the homozygous mice. This incidence is remarkable considering that <3% of WT controls have SOAEs. The predominance of SOAEs >15 kHz correlates with the loss of Hensen's stripe. Results from mice lacking CEACAM16 are consistent with the idea that the organ of Corti evolved to maximize the gain of the cochlear amplifier while preventing large oscillations. Changes in TM structure appear to influence the balance between energy generation and dissipation such that the system becomes unstable. PMID:25080593

  9. Spontaneous emission control in high-extraction efficiency plasmonic crystals.

    PubMed

    Iwase, Hideo; Englund, Dirk; Vuckovic, Jelena

    2008-01-01

    We experimentally and theoretically investigate exciton-field coupling for the surface plasmon polariton (SPP) in waveguide-confined (WC) anti-symmetric modes of hexagonal plasmonic crystals in InP-TiOAu-TiO-Si heterostructures. The radiative decay time of the InP-based transverse magnetic (TM)-strained multi-quantum well (MQW) coupled to the SPP modes is observed to be 2.9-3.7 times shorter than that of a bare MQW wafer. Theoretically we find that 80 % of the enhanced photoluminescence (PL) is emitted into SPP modes, and 17 % of the enhanced PL is redirected into WC-anti-symmetric modes. In addition to the direct coupling of the excitons to the plasmonic modes, this demonstration is also useful for the development of high-temperature SPP lasers, the development of highly integrated photo-electrical devices, or miniaturized biosensors. PMID:18521174

  10. Coke pushing emission control system

    SciTech Connect

    Kwasnoski, D.; Symons, C.

    1980-07-08

    A method is described for controlling coke oven emissions comprising the steps of: (A) aligning a one-spot, open-top coke quenching car with the coke oven, (B) providing a coke guide from the coke oven to the car, (C) positioning a fume hood over the car, with the fume hood having a length about equal to the length of the car, (D) pushing hot coke from the coke oven through the coke guide and into the car, (E) withdrawing gases from the fume hood during step (D) and passing said gases to gas cleaning equipment at a gas flowrate of between about 1000 and about 3500 scfmd per ton of coke pushed under step (D), and (F) substantially upon completion of step (E) moving the car from under the fume hood to a quenching station with the hot coke in the car exposed to the atmosphere and without further withdrawal of gases from the hot coke to the gas cleaning equipment.

  11. Ecological controls over monoterpene emissions from confiers

    SciTech Connect

    Lerdau, M.T.

    1994-01-01

    Ecological controls over monoterpene emissions from two species of conifers, Ponderosa pine and Douglas fir are studied. Monoterpenes are hydrocarbons that serve as part of these plant's chemical defense system. They are highly volatile and make up approximately 40% of the reduced carbon budget of the lower atmosphere playing a major role in tropospheric photochemistry. Previous research has emphasized the controls over emissions from any one plant at any one time. This paper considers some of the controls over the baseline emission rates from different plants. In field studies on Ponderosa pine and greenhouse experiments with Douglas fir in which photosynthesis, tissue chemistry, and monoterpene emissions were measured, there is a strong correlation between the concentration of particular monoterpenes within foliage and emissions from that foliage. Changes in pine photosynthesis were not correlated with changes in monoterpene emissions. In Douglas fir a strong relationship existed among nitrogen availability, phenology (seasonal plant growth), and monoterpene concentration and emission. When foliage is not expanding, there is a direct relationship among nitrogen availability and monoterpene concentrations and emissions. However, during that time of the year when needles are expanding, there is a negative relationship among nitrogen availability and monoterpene concentrations and emissions. From these results I have parameterized a model of monoterpene emissions from vegetation that runs as a subroutine of an ecosystem gas exchange model. The model includes the physiochemical controls on instantaneous flux found in previous work and biological controls on baseline emission rates. Results from initial simulations suggest that low temperatures can decouple monoterpene concentrations from monoterpene emissions. These results also indicate that herbivory could be a major factor controlling monoterpene emissions from forests.

  12. Brain modularity controls the critical behavior of spontaneous activity.

    PubMed

    Russo, R; Herrmann, H J; de Arcangelis, L

    2014-01-01

    The human brain exhibits a complex structure made of scale-free highly connected modules loosely interconnected by weaker links to form a small-world network. These features appear in healthy patients whereas neurological diseases often modify this structure. An important open question concerns the role of brain modularity in sustaining the critical behaviour of spontaneous activity. Here we analyse the neuronal activity of a model, successful in reproducing on non-modular networks the scaling behaviour observed in experimental data, on a modular network implementing the main statistical features measured in human brain. We show that on a modular network, regardless the strength of the synaptic connections or the modular size and number, activity is never fully scale-free. Neuronal avalanches can invade different modules which results in an activity depression, hindering further avalanche propagation. Critical behaviour is solely recovered if inter-module connections are added, modifying the modular into a more random structure. PMID:24621482

  13. Brain modularity controls the critical behavior of spontaneous activity

    NASA Astrophysics Data System (ADS)

    Russo, R.; Herrmann, H. J.; de Arcangelis, L.

    2014-03-01

    The human brain exhibits a complex structure made of scale-free highly connected modules loosely interconnected by weaker links to form a small-world network. These features appear in healthy patients whereas neurological diseases often modify this structure. An important open question concerns the role of brain modularity in sustaining the critical behaviour of spontaneous activity. Here we analyse the neuronal activity of a model, successful in reproducing on non-modular networks the scaling behaviour observed in experimental data, on a modular network implementing the main statistical features measured in human brain. We show that on a modular network, regardless the strength of the synaptic connections or the modular size and number, activity is never fully scale-free. Neuronal avalanches can invade different modules which results in an activity depression, hindering further avalanche propagation. Critical behaviour is solely recovered if inter-module connections are added, modifying the modular into a more random structure.

  14. Tuning of spontaneous emission in photonic crystals by resonant energy transfer and magnetic fields

    NASA Astrophysics Data System (ADS)

    Libaers, W.; Baert, K.; Vallée, R. A. L.; Kolaric, B.; Clays, K.

    2008-04-01

    The fluorescence of emitters embedded in a photonic crystal is known to be inhibited by the presence of a photonic pseudo-gap acting in their emission range. Here we present a comparative study of the influence of the pseudo-gap on the fluorescence emission of either organic dyes or nanocrystals embedded within a photonic crystal. Our results clearly show that the optical properties of the emitters are primarily controlled by the presence of a pseudo-gap which causes inhibition of the emission in both cases, regardless of the differences in chemical composition. These findings are mainly attributed to a decrease of the number of available photonic modes for radiative decay of the emitter in a photonic crystal compared to the effective homogeneous medium. Furthermore, we show that a photonic crystal can be used to control the fluorescence energy transfer (FRET) between donor-acceptor (D-A) pairs of dyes. Finally, we show that the application of an external magnetic field can finely tune the emission characteristics of emitters with a permanent magnetic moment.

  15. Validity of the Relation Between Spontaneous and Stimulated Emissions in Semiconductors

    NASA Technical Reports Server (NTRS)

    Ning, Cun-Zheng; Saini, Subhash (Technical Monitor)

    1999-01-01

    The Einstein relation between spontaneous emission and absorption was originally derived for a system consists of a two-state subsystem representing matter and harmonic fields representing radiation. The derivation is based on the detailed balance between these two subsystems under thermal equilibrium. The relationship was later investigated in connection with the interactions between radiation field and solids or semiconductors. The simple derivation dose not hold for semiconductors in general. In certain limiting cases, simple relation was obtained. The validity of this relation is important not only because of its fundamental role connecting two of the most fundamental optical processes in semiconductors, but mostly also because of its wide use as a practical method to measure the optical gain of a semiconductor. The validity of this relation for semiconductors has been an issue of controversial for some time. In this paper we numerically examine the validity of this relationship for several different lineshapes including Lorentzian, Gaussian, Sech, and a convoluted double Lorentzians (CDL). We find out that at relatively low density above transparency level, all first three lineshapes violate the Einstein relation. The relation is approximately valid at high density. At very high density, the validity of the Einstein relation holds well for all three lineshapes. The reason behind this observation is explained. The CDL lineshape has been shown analytically to obey the Einstein relationship previously. We show that for a 2D semiconductor with parabolic bands, the CDL lineshape can be integrated analytically. This analytic lineshape is compared with a simple Lorentzian lineshape.

  16. Wavelength swept amplified spontaneous emission source for high speed retinal optical coherence tomography at 1060 nm.

    PubMed

    Eigenwillig, Christoph M; Klein, Thomas; Wieser, Wolfgang; Biedermann, Benjamin R; Huber, Robert

    2011-08-01

    The wavelength swept amplified spontaneous emission (ASE) source presented in this paper is an alternative approach to realize a light source for high speed swept source optical coherence tomography (OCT). ASE alternately passes a cascade of different optical gain elements and tunable optical bandpass filters. In this work we show for the first time a wavelength swept ASE source in the 1060 nm wavelength range, enabling high speed retinal OCT imaging. We demonstrate ultra-rapid retinal OCT at a line rate of 170 kHz, a record sweep rate at 1060 nm of 340 kHz with 70 nm full sweep width, enabling an axial resolution of 11 ?m. Two different implementations of the source are characterized and compared to each other. The last gain element is either a semiconductor optical amplifier or an Ytterbium-doped fibre amplifier enabling high average output power of >40 mW. Various biophotonic imaging examples provide a wide range of quality benchmarks achievable with such sources. PMID:21780301

  17. Theoretical study of amplified spontaneous emission intensity and bandwidth reduction in polymer

    NASA Astrophysics Data System (ADS)

    Hariri, A.; Sarikhani, S.

    2015-04-01

    Amplified spontaneous emission (ASE), including intensity and bandwidth, in a typical example of BuEH-PPV is calculated. For this purpose, the intensity rate equation is used to explain the reported experimental measurements of a BuEH-PPV sample pumped at different pump intensities from Ip = 0.61 MW/cm2 to 5.2 MW/cm2. Both homogeneously and inhomogeneously broadened transition lines along with a model based on the geometrically dependent gain coefficient (GDGC) are examined and it is confirmed that for the reported measurements the homogeneously broadened line is responsible for the light–matter interaction. The calculation explains the frequency spectrum of the ASE output intensity extracted from the sample at different pump intensities, unsaturated and saturated gain coefficients, and ASE bandwidth reduction along the propagation direction. Both analytical and numerical calculations for verifying the GDGC model are presented in this paper. Although the introduced model has shown its potential for explaining the ASE behavior in a specific sample it can be universally used for the ASE study in different active media.

  18. Calculation of spontaneous emission from a V-type three-level atom in photonic crystals using fractional calculus

    SciTech Connect

    Huang, Chih-Hsien; Hsieh, Wen-Feng [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, 1001 Tahsueh Rd., Hsinchu 300, Taiwan (China); Institute of Electro-Optical Science and Engineering, National Cheng Kung University, 1 Dahsueh Rd., Tainan 701, Taiwan (China); Wu, Jing-Nuo; Cheng, Szu-Cheng [Department of Physics, Chinese Culture University, Yangming Mt., Taipei 111, Taiwan (China); Li, Yen-Yin [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, 1001 Tahsueh Rd., Hsinchu 300, Taiwan (China)

    2011-07-15

    Fractional time derivative, an abstract mathematical operator of fractional calculus, is used to describe the real optical system of a V-type three-level atom embedded in a photonic crystal. A fractional kinetic equation governing the dynamics of the spontaneous emission from this optical system is obtained as a fractional Langevin equation. Solving this fractional kinetic equation by fractional calculus leads to the analytical solutions expressed in terms of fractional exponential functions. The accuracy of the obtained solutions is verified through reducing the system into the special cases whose results are consistent with the experimental observation. With accurate physical results and avoiding the complex integration for solving this optical system, we propose fractional calculus with fractional time derivative as a better mathematical method to study spontaneous emission dynamics from the optical system with non-Markovian dynamics.

  19. Advanced CIDI Emission Control System Development

    Microsoft Academic Search

    Christine Lambert

    2006-01-01

    Ford Motor Company, with ExxonMobil and FEV, participated in the Department of Energy's (DOE) Ultra-Clean Transportation Fuels Program with the goal to develop an innovative emission control system for light-duty diesel vehicles. The focus on diesel engine emissions was a direct result of the improved volumetric fuel economy (up to 50%) and lower CO2 emissions (up to 25%) over comparable

  20. Lifetime distribution of spontaneous emission from line antennas in two-dimensional quasi-periodic photonic crystals

    Microsoft Academic Search

    Xingsheng Xu; Haiyang Hu; Toshiki Yamada; Hongda Chen; Yiquan Wang

    2008-01-01

    We investigate the lifetime distribution functions of spontaneous emission from line antennas embedded in finite-size two-dimensional 12-fold quasi-periodic photonic crystals. Our calculations indicate that two-dimensional quasi-periodic crystals lead to the coexistence of both accelerated and inhibited decay processes. The decay behaviors of line antennas are drastically changed as the locations of the antennas are varied from the center to the

  1. Destruction of amplified spontaneous emission via chemical doping at low-work-function metal\\/conjugated polymer interfaces

    Microsoft Academic Search

    Bertrand Tremolet de Villers; Benjamin J. Schwartz

    2007-01-01

    The authors investigate how the use of different metal electrodes affects the ability of poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) films to undergo amplified spontaneous emission (ASE). High-work-function metals such as Ag or Au have little effect on the ASE threshold, but low-work-function metals such as Ca or Al completely shut off ASE. ASE is restored when a thin spacer layer, such as

  2. Destruction of amplified spontaneous emission via chemical doping at low-work-function metal\\/conjugated polymer interfaces

    Microsoft Academic Search

    Bertrand Tremolet de Villers; Benjamin J. Schwartz

    2007-01-01

    The authors investigate how the use of different metal electrodes affects the ability of poly[2-methoxy-5-(2?-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) films to undergo amplified spontaneous emission (ASE). High-work-function metals such as Ag or Au have little effect on the ASE threshold, but low-work-function metals such as Ca or Al completely shut off ASE. ASE is restored when a thin spacer layer, such as

  3. First Observation of Self-Amplified Spontaneous Emission in a Free-Electron Laser at 109 nm Wavelength

    Microsoft Academic Search

    J. Andruszkow; B. Aune; V. Ayvazyan; N. Baboi; R. Bakker; V. Balakin; D. Barni; A. Bazhan; M. Bernard; A. Bosotti; J. C. Bourdon; W. Brefeld; R. Brinkmann; S. Buhler; J.-P. Carneiro; M. Castellano; P. Castro; L. Catani; S. Chel; Y. Cho; S. Choroba; E. R. Colby; W. Decking; P. den Hartog; M. Desmons; M. Dohlus; D. Edwards; H. T. Edwards; B. Faatz; J. Feldhaus; M. Ferrario; M. J. Fitch; K. Flöttmann; M. Fouaidy; A. Gamp; T. Garvey; C. Gerth; M. Geitz; E. Gluskin; V. Gretchko; U. Hahn; W. H. Hartung; D. Hubert; M. Hüning; R. Ischebek; M. Jablonka; J. M. Joly; M. Juillard; T. Junquera; P. Jurkiewicz; A. Kabel; J. Kahl; H. Kaiser; T. Kamps; V. V. Katelev; J. L. Kirchgessner; M. Körfer; L. Kravchuk; G. Kreps; J. Krzywinski; T. Lokajczyk; R. Lange; B. Leblond; M. Leenen; J. Lesrel; M. Liepe; A. Liero; T. Limberg; R. Lorenz; Lu Hui Hua; Lu Fu Hai; C. Magne; M. Maslov; G. Materlik; A. Matheisen; J. Menzel; P. Michelato; W.-D. Möller; A. Mosnier; U.-C. Müller; O. Napoly; A. Novokhatski; M. Omeich; H. S. Padamsee; C. Pagani; F. Peters; B. Petersen; P. Pierini; J. Pflüger; P. Piot; B. Phung Ngoc; L. Plucinski; D. Proch; K. Rehlich; S. Reiche; D. Reschke; I. Reyzl; J. Rosenzweig; J. Rossbach; S. Roth; E. L. Saldin; W. Sandner; Z. Sanok; H. Schlarb; G. Schmidt; P. Schmüser; J. R. Schneider; E. A. Schneidmiller; H.-J. Schreiber; S. Schreiber; P. Schütt; J. Sekutowicz; L. Serafini; D. Sertore; S. Setzer; S. Simrock; B. Sonntag; B. Sparr; F. Stephan; V. A. Sytchev; S. Tazzari; F. Tazzioli; M. Tigner; M. Timm; M. Tonutti; E. Trakhtenberg; R. Treusch; D. Trines; V. Verzilov; T. Vielitz; V. Vogel; G. V. Walter; R. Wanzenberg; T. Weiland; H. Weise; J. Weisend; M. Wendt; M. Werner; M. M. White; I. Will; S. Wolff; M. V. Yurkov; K. Zapfe; P. Zhogolev; F. Zhou

    2000-01-01

    We present the first observation of self-amplified spontaneous emission (SASE) in a free-electron laser (FEL) in the vacuum ultraviolet regime at 109 nm wavelength (11 eV). The observed free-electron laser gain (approximately 3000) and the radiation characteristics, such as dependency on bunch charge, angular distribution, spectral width, and intensity fluctuations, are all consistent with the present models for SASE FELs.

  4. Electrostastic control of spontaneous curvature in catanionic reverse micelles.

    PubMed

    Abécassis, Benjamin; Testard, Fabienne; Arleth, Lise; Hansen, Steen; Grillo, Isabelle; Zemb, Thomas

    2007-09-25

    By means of small-angle neutron scattering and conductivity measurements, we study the microstructure of octylammoniumoctanoate/octane/water catanionic reverse microemulsions with an excess of anionic or cationic surfactant. Increasing the surface charge makes the microemulsion able to incorporate much more water than in the neutral case, up to 10 water molecules per surfactant. Even with charges in the surfactant film, wormlike micelles are present in the microemulsion domain. Along water dilution lines, the classical rod-to-sphere transition due to the minimization of the curvature energy of the rigid surfactant film is observed. When temperature is decreased, a re-entrant phase transition associated with the liquid-gas equilibrium of attractive cylinders is observed. Using the framework of the Tlusty-Safran theory, attraction could originate from junctions between wormlike reverse micelles. In any case, the spontaneous curvature of the catanionic surfactant film depends on both the temperature and the net charge, whatever the sign of the latter. PMID:17711317

  5. Analysis and simulation of nonlinearity and effects of spontaneous emission in Schottky-junction-based plasmonic amplifiers.

    PubMed

    Livani, Abdolber Mallah; Kaatuzian, Hassan

    2015-07-01

    An amplifier that operates on surface plasmon polaritons has been analyzed and simulated. Nonlinearity behavior and the spontaneous emission effects of the plasmonic amplifier are investigated in this paper. A rate equations approach has been used in which parameters are derived from simulation results of the plasmonic amplifier (Silvaco/ATLAS). Details on the method of this derivation are included, which were not previously reported. Rate equations are solved numerically by MATLAB codes. These codes verify the Silvaco results. The plasmonic amplifier operates on surface plasmons with a free-space wavelength of 1550 nm. Results show that, even without the effect of spontaneous emission, gain of the plasmonic amplifier saturates in high input levels. Saturation power, which can be used for comparing nonlinearity of different amplifiers, is 2.1 dBm for this amplifier. Amplified spontaneous emission reduces the gain of the amplifiers, which is long. There is an optimum value for the length of the amplifier. For the amplifier of this work, the optimum length for the small signal condition is 265 ?m. PMID:26193159

  6. Effortful control and spontaneous regulation of emotional behavior in children 

    E-print Network

    Kieras, Jessica E

    2013-02-22

    The development of Effortful Control and Regulation of Emotion in children was examined in this study. Of particular interest was the relationship between self-regulation and responses to social norms. Participants were between ages three and five...

  7. Effortful control and spontaneous regulation of emotional behavior in children

    E-print Network

    Kieras, Jessica E

    2013-02-22

    The development of Effortful Control and Regulation of Emotion in children was examined in this study. Of particular interest was the relationship between self-regulation and responses to social norms. Participants were between ages three and five...

  8. Comment on “Competition between coherent emission and broadband spontaneous emission in the quantum free electron laser” [Phys. Plasmas 20, 033106 (2013)

    SciTech Connect

    Petrillo, V.; Rossi, A. R.; Serafini, L. [Università di Milano-INFN, Via Celoria, 16 Milano (Italy)] [Università di Milano-INFN, Via Celoria, 16 Milano (Italy)

    2013-12-15

    We point out that in the equation for the electron distribution evolution during Thomson/Compton or undulator radiation used in the paper: “Competition between coherent emission and broadband spontaneous emission in the quantum free electron laser” by G. R. M. Robb and R. Bonifacio [Phys. Plasmas 20, 033106 (2013)], the weight function should be the distribution of the number of emitted photons and not the photon energy distribution. Nevertheless, the considerations expressed in this comment do not alter the conclusions drawn in the paper in object.

  9. Spontaneous centralization of control in a network of company ownerships.

    PubMed

    Krause, Sebastian M; Peixoto, Tiago P; Bornholdt, Stefan

    2013-01-01

    We introduce a model for the adaptive evolution of a network of company ownerships. In a recent work it has been shown that the empirical global network of corporate control is marked by a central, tightly connected "core" made of a small number of large companies which control a significant part of the global economy. Here we show how a simple, adaptive "rich get richer" dynamics can account for this characteristic, which incorporates the increased buying power of more influential companies, and in turn results in even higher control. We conclude that this kind of centralized structure can emerge without it being an explicit goal of these companies, or as a result of a well-organized strategy. PMID:24324594

  10. ON THE ACHIEVABLE INFORMATION RATE OF ASYMMETRIC OPTICAL FIBER CHANNELS WITH AMPLIFIER SPONTANEOUS EMISSION NOISE

    E-print Network

    Li, Tiffany Jing

    ON THE ACHIEVABLE INFORMATION RATE OF ASYMMETRIC OPTICAL FIBER CHANNELS WITH AMPLIFIER SPONTANEOUS, ABSTRACT This work motivated need understand fundamental limit channel capacities optical fiber of best­known codes like turbo codes optical fiber communication channels. INTRODUCTION Consider optically

  11. Less Costly Catalysts for Controlling Engine Emissions

    SciTech Connect

    Parks, II, James E [ORNL

    2010-01-01

    Lowering the fuel consumption of transportation vehicles could decrease both emissions of greenhouse gases and our dependence on fossil fuels. One way to increase the fuel efficiency of internal combustion engines is to run them 'lean,' in the presence of more air than needed to burn all of the fuel. It may seem strange that engines are usually designed to run with fuel and air at stoichiometric balance, or even fuel rich. However, the way emissions have been controlled with catalytic converters has required some unburned fuel in the exhaust, especially for controlling the nitrogen oxide pollutants NO and NO{sub 2} (called NO{sub x}). On page 1624 of this issue, Kim et al. (1) report encouraging results for catalysts that can process NO{sub x} in lean-burn engines. These perovskite oxide catalysts may help reduce or even eliminate the need for expensive and scarce platinum group metals (PGMs) in emission control catalysts.

  12. Nanophotonic control of circular dipole emission.

    PubMed

    le Feber, B; Rotenberg, N; Kuipers, L

    2015-01-01

    Controlling photon emission by single emitters with nanostructures is crucial for scalable on-chip information processing. Nowadays, nanoresonators can affect the lifetime of linear dipole emitters, while nanoantennas can steer the emission direction. Expanding this control to the emission of orbital angular momentum-changing transitions would enable a future coupling between solid state and photonic qubits. As these transitions are associated with circular dipoles, such control requires knowledge of the interaction of a complex dipole with optical eigenstates containing local helicity. We experimentally map the coupling of classical, circular dipoles to photonic modes in a photonic crystal waveguide. We show that, depending on the combination of the local helicity of the mode and the dipole helicity, circular dipoles can couple to left- or rightwards propagating modes with a near-unity directionality. The experimental maps are in excellent agreement with calculations. Our measurements, therefore, demonstrate the possibility of coupling the spin to photonic pathway. PMID:25833305

  13. Nanophotonic control of circular dipole emission

    NASA Astrophysics Data System (ADS)

    Le Feber, B.; Rotenberg, N.; Kuipers, L.

    2015-04-01

    Controlling photon emission by single emitters with nanostructures is crucial for scalable on-chip information processing. Nowadays, nanoresonators can affect the lifetime of linear dipole emitters, while nanoantennas can steer the emission direction. Expanding this control to the emission of orbital angular momentum-changing transitions would enable a future coupling between solid state and photonic qubits. As these transitions are associated with circular dipoles, such control requires knowledge of the interaction of a complex dipole with optical eigenstates containing local helicity. We experimentally map the coupling of classical, circular dipoles to photonic modes in a photonic crystal waveguide. We show that, depending on the combination of the local helicity of the mode and the dipole helicity, circular dipoles can couple to left- or rightwards propagating modes with a near-unity directionality. The experimental maps are in excellent agreement with calculations. Our measurements, therefore, demonstrate the possibility of coupling the spin to photonic pathway.

  14. Reduced threshold of optically pumped amplified spontaneous emission and narrow line-width electroluminescence at cutoff wavelength from bilayer organic waveguide devices.

    PubMed

    Chang, Jui-Fen; Huang, Yu-Syuan; Chen, Po-Ting; Kao, Ruei-Lin; Lai, Xuan-You; Chen, Chii-Chang; Lee, Cheng-Chung

    2015-06-01

    We present a detailed study of the optically and electrically pumped emission in the BSB-Cz/PVK bilayer waveguide devices. By optical pumping we demonstrate that PVK as a spacer between fluorescent BSB-Cz and ITO electrode allows the significant reduction of the threshold for amplified spontaneous emission (ASE) of BSB-Cz. The simulation provides a better understanding of how the PVK thickness affects the waveguide mode field distribution and hence the ASE threshold of BSB-Cz. On the other hand, the BSB-Cz/PVK bilayer OLED exhibits the external quantum efficiency of >1% and anisotropic electroluminescence with spectrally narrowed edge emission at the cutoff wavelength controlled by the BSB-Cz thickness. When tuning the cutoff wavelength to match the peak gain of BSB-Cz, we demonstrate an intense, particularly narrow edge emission (~5 nm) without obvious degradation of efficiency at a high current density of 1000 mA/cm2, suggesting a reliable device performance for high-power applications and further exploration of electrically-pumped ASE. PMID:26072828

  15. Lifetime distribution of spontaneous emission from line antennas in two-dimensional quasi-periodic photonic crystals

    NASA Astrophysics Data System (ADS)

    Xu, Xingsheng; Hu, Haiyang; Yamada, Toshiki; Chen, Hongda; Wang, Yiquan

    2008-03-01

    We investigate the lifetime distribution functions of spontaneous emission from line antennas embedded in finite-size two-dimensional 12-fold quasi-periodic photonic crystals. Our calculations indicate that two-dimensional quasi-periodic crystals lead to the coexistence of both accelerated and inhibited decay processes. The decay behaviors of line antennas are drastically changed as the locations of the antennas are varied from the center to the edge in quasi-periodic photonic crystals and the location of transition frequency is varied.

  16. Generation of isolated single attosecond hard X-ray pulse in enhanced self-amplified spontaneous emission scheme.

    PubMed

    Kumar, Sandeep; Kang, Heung-Sik; Kim, Dong Eon

    2011-04-11

    The generation of isolated attosecond hard x-ray pulse has been studied under the enhanced self-amplified spontaneous emission (ESASE) scheme with the density and energy modulation of an electron bunch. It is demonstrated in simulation that an isolated attosecond hard x-ray pulse of a high contrast ratio can be produced by adjusting a driver laser wavelength and the energy distribution of an electron bunch. An isolated attosecond pulse of ~146 attosecond full-width half-maximum (FWHM) at 0.1 nm wavelength is obtained with a saturation length of 34 meter for the electron beam parameters of Korean X-ray Free Electron laser. PMID:21503061

  17. Controlling formaldehyde emissions with MBS scrubbing

    SciTech Connect

    Lundquist, P.R. [RMT, Inc., Grand Rapids, MI (United States)

    1998-12-31

    Sodium metabisulfite (MBS)-assisted water scrubbing was selected as the most cost-effective and reliable technology for removal of dilute formaldehyde emissions from a resin manufacturing plant. Dilute formaldehyde emission streams (e.g., from process hoods, sample hoods, and other miscellaneous captured sources) required treatment in order to meet the anticipated Maximum Achievable Control Technology (MACT) standards and state air toxic requirements. Other conventional technologies (e.g., thermal oxidation, carbon adsorption, and biofiltration) were considered, but later discarded because they were cost prohibitive or technically impractical. Segregation of dilute volatile organic compound (VOC) and hazardous air pollutant (HAP) emissions from other more concentrated VOC and HAP emissions facilitated the use of technologies tailored to the characteristics of each stream type, and thereby provided significant cost savings. While past experience has shown that simple water scrubbing of dilute formaldehyde emissions would not meet generally accepted treatment performance (90+% control), removals in excess of 95% can be readily achieved with the addition of a reactant like MBS to the scrubbing liquor. MBS in solution reacts with formaldehyde absorbed by the scrubber water to form a bisulfite salt, rendering the reacted formaldehyde non-volatile. The reaction accelerates mass transfer of formaldehyde into the scrubbing liquid, thereby decreasing the size and cost of emission control equipment. Design of such systems should also consider the chemistry of the make-up water (and scrubber water) used in the process. Recirculating water scrubbers can be susceptible to carbonate scaling and other inorganic fouling experienced in similar water treatment systems (e.g., air strippers). The addition of salts to the recirculating scrubber solutions can be controlled to limit potential sulfur dioxide emissions and deposits.

  18. Geometry effect on spontaneous emission decay in nanosized Y2O3-Eu3+ particles

    NASA Astrophysics Data System (ADS)

    Zaitsev, S. V.; Yermolayeva, Yu. V.; Gruzintsev, A. N.; Kudrenko, E. A.; Zverkova, I. I.; Bezkrovnyi, O.; Tolmachev, A. V.; Emelchenko, G. A.

    2014-11-01

    A strong influence of shape and size on spontaneous luminescence of Eu atoms has been observed in a new class of Y2O3-Eu3+ nanoparticles including nanospheres, nanopowder and nanoplates. We demonstrate a possibility of engineering recombination time ? in nano-objects by changing the local optical environment.

  19. Spontaneous and thermoinduced photon emission: new methods to detect and quantify oxidative stress in plants

    Microsoft Academic Search

    Michel Havaux

    2003-01-01

    Peroxidation of polyunsaturated fatty acids is one of the main events triggered by oxidative stress in cells. Some lipid peroxidation products are light-emitting species, and their luminescence can be used as an internal marker of oxidative stress. However, this spontaneous chemiluminescence is weak and difficult to measure. Recent studies have shown that an alternative approach that involves measuring thermoluminescence bands

  20. ON THE ACHIEVABLE INFORMATION RATE OF ASYMMETRIC OPTICAL FIBER CHANNELS WITH AMPLIFIER SPONTANEOUS EMISSION NOISE

    E-print Network

    Li, Tiffany Jing

    ON THE ACHIEVABLE INFORMATION RATE OF ASYMMETRIC OPTICAL FIBER CHANNELS WITH AMPLIFIER SPONTANEOUS communication channels. INTRODUCTION Consider an optically amplified fiber communication system us- ing-square channels [3]. The motivation of this work is to investigate the ultimate performance limit on optical fiber

  1. CONTROLLING EMISSIONS FROM FUEL AND WASTE COMBUSTION

    EPA Science Inventory

    Control of emissions from combustion of fuels and wastes has been a traditional focus of air pollution regulations. Significant technology developments of the '50s and '60s have been refined into reliable chemical and physical process unit operations. In the U.S., acid rain legis...

  2. Spontaneous Raman emission in porous silicon at 1.5 m and prospects for a Raman This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-print Network

    Jalali. Bahram

    Spontaneous Raman emission in porous silicon at 1.5 µm and prospects for a Raman amplifier Spontaneous Raman emission in porous silicon at 1.5 µm and prospects for a Raman amplifier L Sirleto1 , M emission and the tuning of the Stokes shift. Finally, we discuss the prospect of a Raman amplifier

  3. Averaged kinetic temperature controlling algorithm: Application to spontaneous alloying in microclusters

    NASA Astrophysics Data System (ADS)

    Kobayashi, Taizo R.; Ikeda, Kensuke S.; Shimizu, Yasushi; Sawada, Shin-ichi

    2003-04-01

    A simple algorithm of velocity scaling is proposed for the isothermal simulation of nonequilibrium relaxation processes accompanied with heat generation or absorption. The algorithm controls the kinetic temperature averaged over an arbitrary time interval at an arbitrary relaxation rate and at an arbitrary velocity scaling interval. The general conditions of controlling temperature are derived analytically and criteria for stable control are established. Our algorithm is applied to simulating the effect of substrate on the "spontaneous alloying" process of metal microclusters [H. Yasuda, H. Mori, M. Komatsu, K. Takeda, and H. Fujita, J. Electron Microsc. 41, 267 (1992)]. The results are compared with the results obtained by the Langevin algorithm in which the kinetic energy of every atom is controlled by respective stochastic heat reservoir. In spite of the marked difference between the two algorithms the relaxation dynamics agree very well in quantity over a sufficient wide range of control parameters.

  4. Distribution of spontaneous emission from an Er3+-doped photonic crystal fiber

    Microsoft Academic Search

    R. F. Cregan; J. C. Knight; P. S. J. Russell; P. J. Roberts

    1999-01-01

    The paper studies the emission of 532-nm light through the photonic crystal cladding of an optically pumped Er3+-doped silica\\/air photonic crystal fiber. The angular emission pattern is compared with the results of a multiple scattering simulation. Good agreement is obtained

  5. Advanced Emissions Control Development Program: Phase III

    SciTech Connect

    G.T. Amrhein; R.T. Bailey; W. Downs; M.J. Holmes; G.A. Kudlac; D.A. Madden

    1999-07-01

    The primary objective of the Advanced Emissions Control Development Program (AECDP) is to develop practical, cost-effective strategies for reducing the emissions of air toxics from coal-fired boilers. The project goal is to effectively control air toxic emissions through the use of conventional flue gas clean-up equipment such as electrostatic precipitators (ESPs), fabric filters (baghouses - BH), and wet flue gas desulfurization systems (WFGD). Development work concentrated on the capture of trace metals, fine particulate, hydrogen chloride and hydrogen fluoride, with an emphasis on the control of mercury. The AECDP project is jointly funded by the US Department of Energy's Federal Energy Technology Center (DOE), the Ohio Coal Development Office within the Ohio Department of Development (OCDO), and Babcock and Wilcox, a McDermott company (B and W). This report discusses results of all three phases of the AECDP project with an emphasis on Phase III activities. Following the construction and evaluation of a representative air toxics test facility in Phase I, Phase II focused on characterization of the emissions of mercury and other air toxics and the control of these emissions for typical operating conditions of conventional flue gas clean-up equipment. Some general comments that can be made about the control of air toxics while burning a high-sulfur bituminous coal are as follows: (1) particulate control devices such as ESP's and baghouses do a good job of removing non-volatile trace metals, (2) particulate control devices (ESPs and baghouses) effectively remove the particulate-phase mercury, but the particulate-phase mercury was only a small fraction of the total for the coals tested, (3) wet scrubbing can effectively remove hydrogen chloride and hydrogen fluoride, and (4) wet scrubbers show good potential for the removal of mercury when operated under certain conditions, however, for certain applications, system enhancements can be required to achieve high removals when the scrubber is operated downstream of an ESP. Phase III (Advanced Concepts and Comparison Coals) testing was directed at the development of enhanced air toxics emissions control strategies to further reduce the emissions of mercury. Phase III results further supported the findings of previous phases and demonstrated several methods of enhancing mercury control for both unscrubbed systems and systems equipped with WFGD. Results confirmed that the addition of sorbents can be used to significantly improve the capture of mercury in downstream particulate collection equipment. In addition, Phase III testing demonstrated three methods of minimizing the potential negative impact of an ESP on downstream control of mercury in WFGD systems. These methods included decreased oxidation air flow, the addition of H{sub 2}S into the flue gas at the scrubber inlet, and the addition of EDTA into the absorber reaction tank.

  6. Control of Spontaneous Ca2+ Transients Is Critical for Neuronal Maturation in the Developing Neocortex.

    PubMed

    Bando, Yuki; Irie, Katsumasa; Shimomura, Takushi; Umeshima, Hiroki; Kushida, Yuki; Kengaku, Mineko; Fujiyoshi, Yoshinori; Hirano, Tomoo; Tagawa, Yoshiaki

    2014-08-11

    Neural activity plays roles in the later stages of development of cortical excitatory neurons, including dendritic and axonal arborization, remodeling, and synaptogenesis. However, its role in earlier stages, such as migration and dendritogenesis, is less clear. Here we investigated roles of neural activity in the maturation of cortical neurons, using calcium imaging and expression of prokaryotic voltage-gated sodium channel, NaChBac. Calcium imaging experiments showed that postmigratory neurons in layer II/III exhibited more frequent spontaneous calcium transients than migrating neurons. To test whether such an increase of neural activity may promote neuronal maturation, we elevated the activity of migrating neurons by NaChBac expression. Elevation of neural activity impeded migration, and induced premature branching of the leading process before neurons arrived at layer II/III. Many NaChBac-expressing neurons in deep cortical layers were not attached to radial glial fibers, suggesting that these neurons had stopped migration. Morphological and immunohistochemical analyses suggested that branched leading processes of NaChBac-expressing neurons differentiated into dendrites. Our results suggest that developmental control of spontaneous calcium transients is critical for maturation of cortical excitatory neurons in vivo: keeping cellular excitability low is important for migration, and increasing spontaneous neural activity may stop migration and promote dendrite formation. PMID:25112282

  7. Neutron emission as a function of fragment energy in the spontaneous fission of /sup 260/Md

    SciTech Connect

    Wild, J.F.; van Aarle, J.; Westmeiser, W.; Lougheed, R.W.; Hulet, E.K.; Moody, K.J.; Dougan, R.J.; Brandt, R.; Patzelt, P.

    1989-04-19

    We have made the first measurement of the number of neutrons emitted in the spontaneous fission of a nuclide in which very high fragment energies dominate the fission process. In bombardments of /sup 254/Es, we produced 28-d /sup 260/Md, which was neutron-counted in a 1-m-diam spherical tank containing a Gd-doped scintillator solution. The average number of neutrons emitted per fission is only 2.58 +- 0.11, substantially less than for other actinides. A direct correlation of neutron multiplicity with fragment excitation energy is clearly demonstrated. 3 refs., 5 figs.

  8. Prompt neutron emission from the spontaneous fission of sup 260 Md

    SciTech Connect

    Wild, J.F.; van Aarle, J.; Westmeier, W.; Lougheed, R.W.; Hulet, E.K.; Moody, K.J.; Dougan, R.J.; Koop, E.; Glaser, R.E.; Brandt, R.; Patzelt, P. (University of California, Lawrence Livermore National Laboratory, Livermore California 94551 (US) Philipps University, D-3550, Marburg an der Lahn, (Federal Republic of Germany))

    1990-02-01

    We have made the first measurement of the number of neutrons emitted from the spontaneous fission of a nuclide in which very high fragment energies dominate the fission process. In bombardments of {sup 254}Es, we produced a large sample of 28-d {sup 260}Md, which was neutron counted in a 1-m-diameter spherical tank containing a Gd-doped scintillator solution. The average number of neutrons emitted per fission is only 2.58{plus minus}0.11, substantially less than for other actinides. A linear dependence of neutron multiplicity on fragment-excitation energy is observed to the highest values of total kinetic energy.

  9. Immune responses during spontaneous control of HIV and AIDS: what is the hope for a cure?

    PubMed Central

    Saez-Cirion, A.; Jacquelin, B.; Barré-Sinoussi, F.; Müller-Trutwin, M.

    2014-01-01

    HIV research has made rapid progress and led to remarkable achievements in recent decades, the most important of which are combination antiretroviral therapies (cART). However, in the absence of a vaccine, the pandemic continues, and additional strategies are needed. The ‘towards an HIV cure’ initiative aims to eradicate HIV or at least bring about a lasting remission of infection during which the host can control viral replication in the absence of cART. Cases of spontaneous and treatment-induced control of infection offer substantial hope. Here, we describe the scientific knowledge that is lacking, and the priorities that have been established for research into a cure. We discuss in detail the immunological lessons that can be learned by studying natural human and animal models of protection and spontaneous control of viraemia or of disease progression. In particular, we describe the insights we have gained into the immune mechanisms of virus control, the impact of early virus–host interactions and why chronic inflammation, a hallmark of HIV infection, is an obstacle to a cure. Finally, we enumerate current interventions aimed towards improving the host immune response. PMID:24821922

  10. Electron multiplication in controlled secondary electron emission

    Microsoft Academic Search

    V. G. Gavalyan; M. P. Lorikyan; A. N. Arvanov

    1983-01-01

    In our present work we attempt to reconcile experimental data on CSEE (controlled secondary electron emission) when strongly ionizing ..cap alpha..-particles pass through various porous media with the mechanism suggested by Jacobs. Unlike weakly ionizing ..beta..-particles, ..cap alpha..-particles produce continuous ionization along their entire trajectory in the layer. In our treatment we will consider electron avalanches which originate deep inside

  11. Canister for fuel evaporative emission control system

    SciTech Connect

    Fukami, A.; Ishii, T.; Mizuno, J.; Noguchi, H.

    1982-07-06

    In a canister for a fuel evaporative emission control system of an automotive vehicle, a deflector of the conical frustum shape is embedded in the adsorbent layer of the canister. A diameter of the deflector gradually increases upwardly and a bottom of the deflector faces to the end of the inlet conduit. Dimensional relations of various parts of the deflector are specified. The deflector may include a check valve mounted on the underside of the bottom of the deflector.

  12. Spontaneous and Stimulated-Emission Spectra of CdSnP2

    Microsoft Academic Search

    J. L. Shay; L. M. Schiavone; E. Buehler; J. H. Wernick

    1972-01-01

    We report the band-edge photoluminescence spectra of CdSnP2 crystals lightly doped with Cu or Ag. The emission from CdSnP2:Cu is dominated by a broad band 0.13 eV below the band gap at 1.240 eV (2°K). The emission from CdSnP2:Ag is much stronger and is dominated by a narrow band-to-band emission with three impurity peaks at slightly longer wavelengths. At the

  13. Controlling NOx emission from industrial sources

    SciTech Connect

    Srivastava, R.K.; Nueffer, W.; Grano, D.; Khan, S.; Staudt, J.E.; Jozewicz, W. [US EPA, Research Triangle Park, NC (US). Office of Research & Development

    2005-07-01

    A number of regulatory actions focused on reducing NOx emissions from stationary combustion sources have been taken in the United States in the last decade. These actions include the Acid Rain NOx regulations, the Ozone Transport Commission's NOx Budget Program, and the NOx SIP Call rulemakings. In addition to these regulations, the recent Interstate Air Quality Rulemaking proposal and other bills in the Congress are focusing on additional reductions of NOx. Industrial combustion sources accounted for about 18016 of NOx emissions in the United States in 2000 and constituted the second largest emitting source category within stationary sources, only behind electric utility sources. Based on these data, reduction of NOx emissions from industrial combustion sources is an important consideration in efforts undertaken to address the environmental concerns associated with NOx. This paper discusses primary and secondary NOx control technologies applicable to various major categories of industrial sources. The sources considered in this paper include large boilers, furnaces and fired heaters, combustion turbines, large IC engines, and cement kilns. For each source category considered in this paper, primary NOx controls are discussed first, followed by a discussion of secondary NOx controls.

  14. Controlling bichromatic emission in scattering gain media.

    PubMed

    de Souza, Miguel A F; Lencina, Alberto; Vaveliuk, Pablo

    2006-05-01

    It is experimentally shown that the competition between the two lasing modes of bichromatic emission in a dye solution with nanoparticle scatterers within the diffuse regime can be externally controlled by varying only the excitation beam diameter and the radiation detector position. It is established that this feature is a consequence of the changes in the reabsorption process strengths between monomer and dimer dye aggregates. The controllable switching of these lasing modes could open the real possibility of implementing previously suggested applications for this effect as optical switches. PMID:16642073

  15. Spontaneous quantum emission from analog white holes in a nonlinear optical medium

    NASA Astrophysics Data System (ADS)

    Finazzi, Stefano; Carusotto, Iacopo

    2014-05-01

    We use a microscopic quantum optical model to compute the spectrum of quantum vacuum emission from strong laser pulses propagating in nonlinear optical media. Similarities and differences with respect to the emission of analog white holes as predicted by quantum field theory in curved spacetime are highlighted. Conceptual issues related to the role played by the material dispersion and to the presence or absence of the horizon are clarified. Critical comparison with available experimental data is made.

  16. Prepulse and amplified spontaneous emission effects on the interaction of a petawatt class laser with thin solid targets

    NASA Astrophysics Data System (ADS)

    Esirkepov, Timur Zh.; Koga, James K.; Sunahara, Atsushi; Morita, Toshimasa; Nishikino, Masaharu; Kageyama, Kei; Nagatomo, Hideo; Nishihara, Katsunobu; Sagisaka, Akito; Kotaki, Hideyuki; Nakamura, Tatsufumi; Fukuda, Yuji; Okada, Hajime; Pirozhkov, Alexander S.; Yogo, Akifumi; Nishiuchi, Mamiko; Kiriyama, Hiromitsu; Kondo, Kiminori; Kando, Masaki; Bulanov, Sergei V.

    2014-05-01

    When a finite contrast petawatt laser pulse irradiates a micron-thick foil, a prepulse (including amplified spontaneous emission) creates a preplasma, where an ultrashort relativistically strong portion of the laser pulse (the main pulse) acquires higher intensity due to relativistic self-focusing and undergoes fast depletion transferring energy to fast electrons. If the preplasma thickness is optimal, the main pulse can reach the target accelerating fast ions more efficiently than an ideal, infinite contrast, laser pulse. A simple analytical model of a target with preplasma formation is developed and the radiation pressure dominant acceleration of ions in this target is predicted. The preplasma formation by a nanosecond prepulse is analyzed with dissipative hydrodynamic simulations. The main pulse interaction with the preplasma is studied with multi-parametric particle-in-cell simulations. The optimal conditions for hundreds of MeV ion acceleration are found with accompanying effects important for diagnostics, including high-order harmonics generation.

  17. Biopolymer based system doped with nonlinear optical dye as a medium for amplified spontaneous emission and lasing

    NASA Astrophysics Data System (ADS)

    Sznitko, Lech; Mysliwiec, Jaroslaw; Karpinski, Pawel; Palewska, Krystyna; Parafiniuk, Kacper; Bartkiewicz, Stanislaw; Rau, Ileana; Kajzar, Francois; Miniewicz, Andrzej

    2011-07-01

    In this paper, we present results of detailed studies on amplified spontaneous emission (ASE) and lasing achieved in a double-layer system consisted of a biopolymer based matrix loaded with 3-(1,1-dicyanoethenyl1)-1phenyl-4,5dihydro-1H-pyrazole organic nonlinear optical dye and photochromic polymer. The laser action was achieved via distributed feedback configuration with third order of Bragg scattering on surface relief grating generated in photochromic polymer. To excite the luminescence, we have used 6 ns pulses of Nd:YAG laser at 532 nm. The ASE and lasing thresholds were estimated to be 17 mJ/cm2 and 11 mJ/cm2, respectively.

  18. Full characterization of the amplified spontaneous emission from a diode-pumped high-power laser system.

    PubMed

    Keppler, S; Hornung, M; Bödefeld, R; Sävert, A; Liebetrau, H; Hein, J; Kaluza, M C

    2014-05-01

    We present the first complete temporal and spatial characterization of the amplified spontaneous emission (ASE) of laser radiation generated by a diode-pumped high-power laser system. The ASE of the different amplifiers was measured independently from the main pulse and was characterized within a time window of -10ms ? t ? 10ms and an accuracy of up to 15fs around the main pulse. Furthermore, the focusability and the energy of the ASE from each amplifier was measured after recompression. Using our analysis method, the laser components, which need to be optimized for a further improvement of the laser contrast, can be identified. This will be essential for laser-matter interaction experiments requiring a minimized ASE intensity or fluence. PMID:24921820

  19. Spontaneous emission from a two-level atom in anisotropic one-band photonic crystals: A fractional calculus approach

    SciTech Connect

    Wu, J.-N.; Huang, C.-H. [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu, Taiwan (China); Cheng, S.-C. [Department of Physics, Chinese Culture University, Taipei, Taiwan (China); Hsieh, W.-F. [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, Hsinchu, Taiwan (China); Institute of Electro-Optical Science and Engineering, National Cheng Kung University, Tainan, Taiwan (China)

    2010-02-15

    Spontaneous emission (SE) from a two-level atom in an anisotropic photonic crystal (PC) is investigated by the fractional calculus. Physical phenomena of the SE are studied analytically by solving the fractional kinetic equations of the SE. There is a dynamical discrepancy between the SE of anisotropic and isotropic PCs. We find that, contrary to the SE phenomenon of the isotropic PC, the SE near the band edge of an anisotropic PC shows no photon-atom bound state. It is consistent with the experimental results of Barth, Schuster, Gruber, and Cichos [Phys. Rev. Lett. 96, 243902 (2006)] that the anisotropic property of the system enhances the SE. We also study effects of dispersion curvatures on the changes of the photonic density of states and the appearance of the diffusion fields in the SE.

  20. Factors controlling dimethylsulfide emission from salt marshes

    NASA Technical Reports Server (NTRS)

    Dacey, John W. H.; Wakeham, S. G.; Howes, B. L.

    1985-01-01

    The factors that control the emission of methylated gases from salt marshes are being studied. Research focusses on dimethylsulfide (DMS) formation and the mechanism of DMS and CH4 emission to the atmosphere. The approach is to consider the plants as valves regulating the emission of methylated gases to the atmosphere with the goal of developing appropriate methods for emission measurement. In the case of CH4, the sediment is the source and transport to the atmosphere occurs primarily through the internal gas spaces in the plants. The source of DMS appears to be dimethyl sulfoniopropionate (DMSP) which may play a role in osmoregulation in plant tissues. Concentrations of DMSP in leaves are typically several-fold higher than in roots and rhizomes. Even so, the large below ground biomass of this plant means that 2/3 of the DMSP in the ecosystem is below ground on the aerial basis. Upon introduction to sediment water, DMSP rapidly decomposes to DMS and acrylic acid. The solubility of a gas (its equilibrium vapor pressure) is a fundamental aspect of gas exchange kinetics. The first comprehensive study was conducted of DMS solubility in freshwater and seawater. Data suggest that the Setchenow relation holds for H at intermediate salinities collected. These data support the concept that the concentration of DMS in the atmosphere is far from equilibrium with seawater.

  1. Spontaneous emission interference enhancement with a {mu}-negative metamaterial slab

    SciTech Connect

    Zeng Xiaodong; Xu Jingping; Yang Yaping [Key Laboratory of Advanced Micro-Structure Materials, Ministry of Education (China); Department of Physics, Tongji University, Shanghai 200092 (China)

    2011-09-15

    The spontaneous decay and quantum interference of a V-type Zeeman atom placed near a {mu}-negative metamaterial (MNG) slab are investigated. Based on the fact that MNG slab supports only TE-polarized surface-plasmon polariton (SPP) modes, the decay rate of the dipole component parallel to the interface would be much larger than that normal to the interface, because one can couple while another decouple to TE modes. Consequently, high-level anisotropic environment is created and the two dipoles can interfere with each other strongly by sharing such SPP modes even if they are orthogonal. In our work, we analyze the influence of the parameters of the MNG slab as well as the atomic location on the interference intensity in detail. In addition, the dissipation of the slab is considered, and the quantum interference is still excellent even with large absorption.

  2. Rat gastroduodenal motility in vivo: interaction of GABA and VIP in control of spontaneous relaxations.

    PubMed

    Krantis, A; Mattar, K; Glasgow, I

    1998-11-01

    Spontaneous relaxations occurring within motor activity in the rat gastroduodenum in vivo can be distinguished by their dependence on either nitric oxide (NO) or ATP. We examined the interaction of gamma-aminobutyric acid (GABA) and vasoactive intestinal peptide (VIP) within pathways controlling this activity in the antrum (S) and duodenum (D) of anesthetized Sprague-Dawley rats, using miniaturized extraluminal foil strain gauges oriented perpendicular to (S1, D1) or in the axis of (S2) the circular smooth muscle. The NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME; 10 mg/kg iv) attenuated (P < 0.05) antral relaxations and, in the duodenum, nonpropagating "intergroup" relaxations. The GABAA receptor antagonist bicuculline (350 micrograms/kg sc) had similar effects. The GABAA agonist 3-amino-1-propanesulfonic acid stimulated L-NAME-sensitive relaxations at S1 and D1. Propagating "grouped" responses were unchanged. VIP (6 micrograms/kg iv) always induced a relaxation of the duodenum, which was attenuated by bicuculline and L-NAME. VIP caused simultaneous responses at S1 and S2; however, the antrum displayed either contraction or relaxation in response to VIP. All antral relaxations in response to VIP were attenuated (P < 0. 05) by L-NAME; however, only VIP-induced relaxations at S1 were sensitive to bicuculline. VIP-induced contractions were also unaffected. GABAA receptors mediate the pathway(s) controlling NO-related spontaneous relaxations of the antrum and duodenal circular muscle. All VIP-induced relaxations are mediated by NO. Spontaneous relaxations of the rat gastroduodenum include responses that involve a GABAAergic NO-related pathway, which is targeted by VIP. In addition, VIP can target NO relaxations of the antrum via other pathways. PMID:9815017

  3. IDENTIFICATION, ASSESSMENT, AND CONTROL OF FUGITIVE PARTICULATE EMISSIONS

    EPA Science Inventory

    The technical manual, designed to assist national, state, and local control agency personnel and industry personnel in evaluating fugitive emission control plans and in developing cost-effective control strategies, describes the identification, assessment, and control of fugitive...

  4. VOLUME 80, NUMBER 23 P H Y S I C A L R E V I E W L E T T E R S 8 JUNE 1998 Local-Field Effects on Spontaneous Emission in a Dense Supercritical Gas

    E-print Network

    Sprik, Rudolf

    on Spontaneous Emission in a Dense Supercritical Gas Frank J. P. Schuurmans, Dennis T. N. de Lang, Gerard H on the spontaneous emission rate of a europium complex in dense supercritical CO2. The refractive index of the supercritical gas is varied from 1.00 to 1.27 by increasing the pressure up to a 1000 bars. Accordingly

  5. Hot stuff controls for VOC emissions

    SciTech Connect

    Yewshenko, P. [Ross Air Systems, Somerville, NJ (United States)

    1995-12-01

    For close to three decades, American industry has paved the way and led the world in controlling volatile organic compound (VOC) emissions. As more and more systems have been installed, the history of operation for the various types of systems has broadened dramatically, spurring significant technological advances, the traditional technologies and those on the cutting edge of VOC control. With the number of technologies available, the environmental professional may have a difficult task choosing the most strategic environmental solution. The conventional, traditional or proven methodology for VOC control has been incineration. Other technologies have been used for very specific applications. In deciding the specific type of incineration system to select, the environmental professional will look at a broad spectrum of evaluation factors. These include initial system cost, operational cost, maintenance requirements, reliability factors and most importantly, the projected success of achieving 99% VOC destruction efficiency. This article provides an overview of the basic differences among incineration technologies.

  6. The research and implementation of coalfield spontaneous combustion of carbon emission WebGIS based on Silverlight and ArcGIS server

    NASA Astrophysics Data System (ADS)

    Zhu, Z.; Bi, J.; Wang, X.; Zhu, W.

    2014-02-01

    As an important sub-topic of the natural process of carbon emission data public information platform construction, coalfield spontaneous combustion of carbon emission WebGIS system has become an important study object. In connection with data features of coalfield spontaneous combustion carbon emissions (i.e. a wide range of data, which is rich and complex) and the geospatial characteristics, data is divided into attribute data and spatial data. Based on full analysis of the data, completed the detailed design of the Oracle database and stored on the Oracle database. Through Silverlight rich client technology and the expansion of WCF services, achieved the attribute data of web dynamic query, retrieval, statistical, analysis and other functions. For spatial data, we take advantage of ArcGIS Server and Silverlight-based API to invoke GIS server background published map services, GP services, Image services and other services, implemented coalfield spontaneous combustion of remote sensing image data and web map data display, data analysis, thematic map production. The study found that the Silverlight technology, based on rich client and object-oriented framework for WCF service, can efficiently constructed a WebGIS system. And then, combined with ArcGIS Silverlight API to achieve interactive query attribute data and spatial data of coalfield spontaneous emmission, can greatly improve the performance of WebGIS system. At the same time, it provided a strong guarantee for the construction of public information on China's carbon emission data.

  7. Suppression of the amplified spontaneous emission in chirped-pulse-amplification lasers by clean high-energy seed-pulse injection

    Microsoft Academic Search

    J. Itatani; J. Faure; M. Nantel; G. Mourou; S. Watanabe

    1998-01-01

    We have suppressed the amplified spontaneous emission in a femtosecond terawatt Ti:sapphire chirped-pulse-amplification (CPA) laser by injecting clean microjoule seed pulses into the regenerative amplifier. The intensity contrast ratio, which is one of the major difficulties in CPA lasers, was improved from ?105 in the original nanojoule injection case to ?107 in the nanosecond scale.

  8. Amplified spontaneous emission and optical gain measurements from pyrromethene 567--doped polymer waveguides and quasi-waveguides.

    PubMed

    Costela, A; García, O; Cerdán, L; García-Moreno, I; Sastre, R

    2008-05-12

    Amplified spontaneous emission from planar waveguides and quasi-waveguides based on Pyrromethene 567-doped poly(methyl methacrylate) thin films deposited onto quartz and glass substrates is investigated. Films with different thickness were prepared and pumped optically at 532 nm with pulses of up to 8 MW/cm(2). Pump thresholds for the onset of ASE emission, optical gains and losses were assessed. Net gain coefficients were estimated by fitting the data provided by variable stripe length measurements with a theoretical expression which takes into account saturation. In this way, net gain coefficients of up to 56 +/- 9 cm(-1) at a pump intensity of 5.3 MW/cm(2) for quasi-waveguides and up to 20.6 +/- 2.7 cm(-1) at a pump intensity of 3.4 MW/cm2 for waveguides, were obtained. Loss coefficients in the waveguides were estimated to be 3.8 +/- 0.4 cm-1 and 6.1 +/- 1.3 cm(-1) for 15 microm and 5 microm thick films, respectively. The results obtained seem to indicate a stronger self-mode-restriction capability in the quasiwaveguides than in conventional total internal-reflection waveguides. PMID:18545406

  9. Coherent optical transition radiation and self-amplified spontaneous emission generated by chicane-compressed electron beams

    SciTech Connect

    Lumpkin, A.H.; /Fermilab; Dejus, R.J.; Sereno, N.S.; /Argonne

    2009-02-01

    Observations of strongly enhanced optical transition radiation (OTR) following significant bunch compression of photoinjector beams by a chicane have been reported during the commissioning of the Linac Coherent Light Source (LCLS) accelerator and recently at the Advanced Photon Source (APS) linac. These localized transverse spatial features involve signal enhancements of nearly a factor of 10 and 100 in the APS case at the 150-MeV and 375-MeV OTR stations, respectively. They are consistent with a coherent process seeded by noise and may be evidence of a longitudinal space charge (LSC) microbunching instability which leads to coherent OTR (COTR) emissions. Additionally, we suggest that localized transverse structure in the previous self-amplified spontaneous emission (SASE) free-electron laser (FEL) data at APS in the visible-UV regime as reported at FEL02 may be attributed to such beam structure entering the FEL undulators and inducing the SASE startup at those structures. Separate beam structures 120 microns apart in x and 2.9 nm apart in wavelength were reported. The details of these observations and operational parameters will be presented.

  10. Approximate Entropy Values Demonstrate Impaired Neuromotor Control of Spontaneous Leg Activity in Infants with Myelomeningocele

    PubMed Central

    Smith, Beth A.; Teulier, Caroline; Sansom, Jennifer; Stergiou, Nicholas; Ulrich, Beverly D.

    2012-01-01

    Purpose One obstacle to providing early intervention to infants with myelomeningocele (MMC) is the challenge of quantifying impaired neuromotor control of movements early in life. Methods We used the nonlinear analysis tool Approximate Entropy (ApEn) to analyze periodicity and complexity of supine spontaneous lower extremity movements of infants with MMC and typical development (TD) at 1, 3, 6 and 9 months of age. Results Movements of infants with MMC were more regular and repeatable (lower ApEn values) than movements of infants with TD indicating less adaptive and flexible movement patterns. For both groups ApEn values decreased with age, and the movements of infants with MMC were less complex than movements of infants with TD. Further, for infants with MMC, lesion level and age of walking onset correlated negatively with ApEn values. Conclusions Our study begins to demonstrate the feasibility of ApEn to identify impaired neuromotor control in infants with MMC. PMID:21829116

  11. Ultraviolet spontaneous and stimulated emissions from ZnO microcrystallite thin films at room temperature

    Microsoft Academic Search

    P. Zu; Z. K. Tang; G. K. L. Wong; M. Kawasaki; A. Ohtomo; H. Koinuma; Y. Segawa

    1997-01-01

    Room-temperature free excition absorption and luminescence are observed in ZnO thin films grown on sapphire substrates by the laser molecular beam epitaxy technique. At moderate optical pumping intensities, an excition-exciton collision induced stimulated emission peak is observed at 390 nm. The existence of this peak is related to the presence of closely packed hexagonally shaped microcrystallites in these films. Stimulated

  12. The Effect of Ear Canal Pressure on Spontaneous Otoacoustic Emissions:. Comparison Between Human and Lizard Ears

    NASA Astrophysics Data System (ADS)

    van Dijk, P.; Manley, G. A.

    2009-02-01

    The center frequency, height and width of peaks in SOAE spectra depend on ear canal pressure. The width is interpreted as a measure of the inner ear source-signal-to-(e.g. thermal)-noise ratio. In humans, width increases with decreasing height. Apparently, ear canal pressure modifies the amplitude of the inner ear emission source signal. In lizards, the relation between peak width and height is not consistent. Here, middle ear transmission changes may account for many the observed amplitude effects.

  13. The Impact of IFNL4 rs12979860 Polymorphism on Spontaneous Clearance of Hepatitis C; A Case-Control Study

    PubMed Central

    Sharafi, Heidar; Alavian, Seyed Moayed; Behnava, Bita; Pouryasin, Ali; Keshvari, Maryam

    2014-01-01

    Background: About 30% of individuals with hepatitis C virus (HCV) infection are able to clear HCV spontaneously. Differences in host genetics affect the outcome of HCV infection. Single nucleotide polymorphisms (SNPs) of the Interferon lambda (IFNL) genes were associated with spontaneous and treatment-induced clearance of HCV infection. Objectives: The aim of this study was to evaluate the association between the IFNL4 rs12979860 SNP and spontaneous clearance of HCV infection in Iranian population. Materials and Methods: A case-control study was designed on 91 cases with spontaneous HCV infection clearance and 259 patients with persistent HCV infection as the control group. The rs12979860 SNP was assessed as the most common IFNL polymorphism by PCR-RFLP method. Results: Distribution of rs12979860 CC genotype in the spontaneous clearance group was around two folds of its distribution in chronic hepatitis C group (P < 0.001, OR = 4.09, 95% CI = 2.44-6.86). Conclusions: The rs12979860 SNP was observed as a strong host genetic factor associated with spontaneous clearance of hepatitis C infection. PMID:25419220

  14. CONTROL OF HYDROCARBON EMISSIONS FROM GASOLINE LOADING BY REFRIGERATION SYSTEMS

    EPA Science Inventory

    The report gives results of a study of the capabilities of refrigeration systems, operated at three temperatures, to control volatile organic compound (VOC) emissions from truck loading at bulk gasoline terminals. Achievable VOC emission rates were calculated for refrigeration sy...

  15. Spontaneous acoustic emission of a corrugated shock wave in the presence of a reflecting surface.

    PubMed

    Wouchuk, J G; López Cavada, J

    2004-10-01

    An analytic model to study perturbation evolution in the space between a corrugated shock and a piston surface is presented. The conditions for stable oscillation patterns are obtained by looking at the poles of the exact Laplace transform. It is seen that besides the standard D'yakov-Kontorovich (DK) mode of oscillation, the shock surface can exhibit an additional finite set of discrete frequencies, due to the interaction with the piston which reflects sound waves from behind. The additional eigenmodes are excited when the shock is launched at t= 0(+) . The first eigenmode (the DK mode) is always present, if the Hugoniot curve has the correct slope in the V-p plane. However, the additional frequencies could be excited for strong enough shocks. The predictions of the model are verified for particular cases by studying a van der Waals gas, as in the work of Phys. Fluids 11, 462 (1999)]; Phys. Rev. Lett. 84, 1180 (2000)]. Only acoustic emission modes are considered. PMID:15600515

  16. Enhancement of optical gain and amplified spontaneous emission due to waveguide geometry in the conjugated polymer poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene

    NASA Astrophysics Data System (ADS)

    Lampert, Zach E.; Papanikolas, John M.; Lewis Reynolds, C.

    2013-02-01

    We report enhanced amplified spontaneous emission (ASE) and optical gain performance in a conjugated polymer (CP)-based thin film waveguide (WG) Si(100)/SiO2/poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV) by encapsulating the active layer with a transparent dielectric film of poly(methyl methacrylate) (PMMA). With index matched SiO2 and PMMA claddings, symmetric WGs are formed that exhibit increased mode confinement and reduced propagation loss enabling lower ASE threshold (40%) and higher optical gain (50%) compared to Si(100)/SiO2/MEH-PPV/air asymmetric WGs. An extremely large net gain coefficient of 500 cm-1 is achieved under picosecond pulse excitation, which is >4× larger than values previously reported in the literature. Fabrication of symmetric WGs requires no complex processing techniques, thus offering a simple, low-cost approach for effectively controlling the ASE behavior of CP-based WGs and related optical devices.

  17. Control of Initiation, Rate, and Routing of Spontaneous Capillary-Driven Flow of Liquid Droplets through Microfluidic Channels on

    E-print Network

    Ismagilov, Rustem F.

    through Microfluidic Channels on SlipChip Rebecca R. Pompano, Carol E. Platt, Mikhail A. Karymov to initiate and control the rate of spontaneous liquid-liquid flow through microfluidic channels. In contrast and operation of flow in microfluidic applications that do not require external power, valves, or pumps

  18. COMPUTER-CONTROLLED, REAL-TIME AUTOMOBILE EMISSIONS MONITORING SYSTEM

    EPA Science Inventory

    A minicomputer controlled automotive emissions sampling and analysis system (the Real-Time System) was developed to determine vehicular modal emissions over various test cycles. This data acquisition system can sample real-time emissions at a rate of 10 samples/s. A buffer utiliz...

  19. Control of gas emissions in underground coal mines

    Microsoft Academic Search

    Klaus Noack

    1998-01-01

    A high level of knowledge is now available in the extremely relevant field of underground gas emissions from coal mines. However, there are still tasks seeking improved solutions, such as prediction of gas emissions, choice of the most suitable panel design, extension of predrainage systems, further optimization of postdrainage systems, options for the control of gas emissions during retreat mining

  20. Ultrahigh Spontaneous Emission Quantum Efficiency, 99.7% Internally And 72% Externally, From AlGaAs\\/GaAs\\/AlGaAs Double Heterostructures

    Microsoft Academic Search

    I. Schnitzer; E. Yablonovitch; C. Caneau; A. Ersen; T. J. Gmitter

    1992-01-01

    Thin film (5000~),ALGaAs\\/GaAs\\/AlGaAs double heterostructures, are floated off thcir substrates by the epitaxial liftoff technique and mounted on various high reflectivity surfaces. From the absolute photoluminescence intensity, we measure internal and external quantum efficiencies of 99.7% and 72%, respectively. This novel configuration, as wcll as its world rccord spontaneous emission quantum efficiency, is expected to play a significant role in

  1. Ultrahigh spontaneous emission quantum efficiency, 99.7% internally and 72% externally, from AlGaAs\\/GaAs\\/AlGaAs double heterostructures

    Microsoft Academic Search

    I. Schnitzer; E. Yablonovitch; C. Caneau; T. J. Gmitter

    1993-01-01

    Optically thin AlGaAs\\/GaAs\\/AlGaAs double heterostructures, (5000 A?), are floated off their substrates by the epitaxial liftoff technique and mounted on various high reflectivity surfaces. From the absolute photoluminescence intensity, we measure internal and external quantum efficiencies of 99.7% and 72%, respectively. High spontaneous emission quantum efficiency, is important for photon number squeezed light, diode lasers, single-mode light-emitting-diodes, optical interconnects, and

  2. Role of amplified spontaneous emission in optical free-space communication links with optical amplification: impact on isolation and data transmission and utilization for pointing, acquisition, and

    Microsoft Academic Search

    Peter J. Winzer; Andras Kalmar; Walter R. Leeb

    1999-01-01

    We investigate the role of amplified spontaneous emission (ASE) produced by an optical booster amplifier at the transmitter of free-space optical communication links. In a communication terminal with a single telescope for both transmission and reception, this ASE power has to be taken into account in connection with transmit-to-receive channel isolation, especially since it partly occupies the same state of

  3. Widely tunable S-band fiber-ring lasers and broadband amplified spontaneous emission sources with thulium-doped fluoride fibers

    Microsoft Academic Search

    H. Chen; F. Babin; M. Leblanc; G. He; G. W. Schinn

    2003-01-01

    This paper reports our investigation on widely tunable fiber-ring lasers and broadband amplified spontaneous emission (ASE) light sources with thulium-doped fluoride fibers (TDFs). The experimental results for thulium-doped optical fiber amplifiers will also be discussed. We achieved widely tunable fiber lasers that had tuning ranges of 94 nm with 1550 nm + 1050 nm pump configurations and of 85 nm

  4. CLASSICAL AREAS OF PHENOMENOLOGY: Modification of spontaneous emission rate of micrometer-sized light sources using hollow-core photonic crystal fibers

    Microsoft Academic Search

    Jiao-Hua Lu; Zi-Ming Meng; Hai-Ying Liu; Tian-Hua Feng; Qiao-Feng Dai; Li-Jun Wu; Qi Guo; Wei Hu; Sheng Lan

    2009-01-01

    We investigate numerically and experimentally the modification of the spontaneous emission rate for micrometer-sized light sources embedded in a hollow-core photonic crystal fiber (HCPCF). The diameter of the light source is deliberately chosen such that they could be easily introduced into the central hole of the hollow-core photonic crystal fiber by capillary force. The photoluminescence from the microparticles is measured

  5. Spectral hole burnings at high energy tails in spontaneous emission and hot carrier relaxation in InGaAsP lasers

    Microsoft Academic Search

    M. Yamanishi; I. Suemune; K. Nonomura; N. Mikoshiba

    1983-01-01

    Spectral hole burnings in spontaneous emission spectra from 1.3 ..mu..m InGaAsP lasers were found. The results are understood on the basis of population burnings of holes associated with the saturation of intervalence-band absorption. Theoretical results on hot carrier relaxation are shown to explain the population burnings, pointing out an importance of nonequilibrium optical phonon populations in the active layers of

  6. Ongoing Spontaneous Activity Controls Access to Consciousness: A Neuronal Model for Inattentional Blindness

    Microsoft Academic Search

    Stanislas Dehaene; Jean-Pierre Changeux

    2005-01-01

    Even in the absence of sensory inputs, cortical and thalamic neurons can show structured patterns of ongoing spontaneous activity, whose origins and functional significance are not well understood. We use computer simulations to explore the conditions under which spontaneous activity emerges from a simplified model of multiple interconnected thalamocortical columns linked by long-range, top-down excitatory axons, and to examine its

  7. Fuel evaporative emission control apparatus for vehicles

    SciTech Connect

    Mizuno, J.; Fukami, A.; Ishii, T.; Noguchi, H.

    1983-09-13

    A fuel evaporative emission control apparatus is disclosed comprising a vessel having an adsorbent layer therein for adsorbing a vaporized fuel, and a vaporized fuel inlet conduit inserted in the adsorbent layer, wherein the improvement comprises a flow deflector of a hollow conical shape having a diameter gradually increasing upward, the deflector being embedded in the adsorbent layer. The vertical angle (a) of the flow deflector is adjusted to 60/sup 0/ to 120/sup 0/, the ratio (S1/S2) of the sectional area (S1) of the largest-diameter end portion of the flow deflector to the sectional area (S2) of the adsorbent layer is adjusted to 0.4 to 0.6, the ratio (a/b) of the distance (a) between the largest-diameter end portion of the flow deflector and the top end of the adsorbent layer to the distance (b) between the largest-diameter end portion of the flow deflector and the side end of the adsorbent layer is adjusted to at least 1.5, and the distance (a) is made smaller than the sum (g+b) of said distance (b) and the axial length (g) of the conduit in the adsorbent layer.

  8. High cell density induces spontaneous bifurcations of dissolved oxygen controllers during CHO cell fermentations.

    PubMed

    Chung, John D; Chang, Conway C; Groves, James Ashley

    2003-10-20

    High cell density cultures of CHO cells growing in a bioreactor under dissolved oxygen control were found to undergo spontaneous bifurcations and a subsequent loss of stability some time into the fermentation. This loss of stability was manifested by sustained and amplified oscillations in the bioreactor dissolved oxygen concentration and in the oxygen gas flow rate to the reactor. To identify potential biological and operational causes for the phenomenon, linear stability analysis was applied in a neighborhood of the experimentally observed bifurcation point. The analysis revealed that two steady state process gains, K(P1) and K(P2), regulated k(l)a and gas phase oxygen concentration inputs, respectively, and the magnitude of K(P1) was found to determine system stability about the bifurcation point. The magnitude of K(P1), and hence the corresponding open-loop steady state gain K(OL1), scaled linearly with the bioreactor cell density, increasing with increasing cell density. These results allowed the generation of a fermentation stability diagram, which partitioned K(C)-N operating space into stable and unstable regions separated by the loci of predicted critically stable controller constants, K(C,critical), as a function of bioreactor cell density. This consistency of this operating diagram with experimentally observed changes in system stability was demonstrated. We conclude that time-dependent increases in cell density are the cause of the observed instabilities and that cell density is the critical bifurcation parameter. The results of this study should be readily applicable to the design of a more robust controller. PMID:12966579

  9. Active control of excessive sound emission on a mobile device.

    PubMed

    Jeon, Se-Woon; Youn, Dae Hee; Park, Young-Cheol; Lee, Gun-Woo

    2015-04-01

    During a phone conversation, loud vocal emission from the far-end to the near-end space can disturb nearby people. In this paper, the possibility of actively controlling such unwanted sound emission using a control source placed on the mobile device is investigated. Two different approaches are tested: Global control, minimizing the potential energy measured along a volumetric space surface, and local control, minimizing the squared sound pressure at a discrete point on the phone. From the test results, both approaches can reduce the unwanted sound emission by more than 6?dB in the frequency range up to 2 kHz. PMID:25920885

  10. Isoflurane anesthesia in sandhill cranes (Grus canadensis): minimal anesthetic concentration and cardiopulmonary dose-response during spontaneous and controlled breathing.

    PubMed

    Ludders, J W; Rode, J; Mitchell, G S

    1989-04-01

    Information on species differences in responses to inhalation anesthetics has been established in a variety of mammalian and non-mammalian species, but comparable studies have not been reported in birds. The purpose of this study was to determine minimal anesthetic concentration and cardiopulmonary concentration-response effects of isoflurane in Sandhill cranes. Six cranes were anesthetized with isoflurane in oxygen. Gases sampled through a polyethylene tube inserted to the distal end of an endotracheal tube were used for measurements of isoflurane concentrations using an infrared gas analyzer. Body temperature was maintained at 40 +/- 0.5 degrees C. The minimal anesthetic concentration for isoflurane was determined during spontaneous ventilation, and concentration-response data were collected at 1, 1.5, and 2.0 times the minimal anesthetic concentration. Concentration-response data were repeated during mechanically controlled breathing with PaCO2 maintained between 27 and 35 mm Hg. The minimal anesthetic concentration for isoflurane was 1.34 +/- 0.14 vol% (mean +/- SD). Concentration-dependent respiratory depression during spontaneous breathing was evidenced in all cranes by an increase in PaCO2. Isoflurane induced apnea in two of the cranes during spontaneous ventilation at 2 times the minimal anesthetic concentration. As the concentration of isoflurane was increased, mean arterial blood pressure decreased during both spontaneous and controlled ventilation. Mean arterial blood pressure was higher during controlled ventilation than during spontaneous ventilation. The minimal anesthetic concentration for isoflurane in Sandhill cranes is similar to values for isoflurane minimal anesthetic concentration in mammals. Isoflurane has dose-dependent effects on cardiopulmonary function qualitatively similar to those observed in mammals. PMID:2929984

  11. The oxygen free radicals control MMP-9 and transcription factors expression in the spontaneously hypertensive rat.

    PubMed

    Duansak, Naphatsanan; Schmid-Schönbein, Geert W

    2013-11-01

    Oxygen free radical and matrix metalloproteinases-9 (MMP-9) play an important pathophysiological role in the development of chronic hypertension. MMP-9 activities are regulated at different levels. We hypothesize that as mediators of the expression of MMP-9 the transcription factors like nuclear factor kappa B (NF-?B), c-fos and retinoic acid receptors-? (RAR-?) with binding sites to the MMP-9 promoter are overexpressed in the spontaneously hypertensive rat (SHR) in a process that is regulated by oxygen free radicals. Transcription factor NF-?B, c-fos and RAR-? expression levels were determined by immunohistochemistry in renal, cardiac and mesentery microcirculation of the SHR and its normotensive control, the Wistar Kyoto (WKY) rat. The animals were treated with a superoxide scavenger (Tempol) for eight weeks. The elevated plasma levels of thiobarbituric acid reactive substances and MMP-9 levels in the SHR were significantly decreased by Tempol treatment (P<0.05). The NF-?B, c-fos and RAR-? expression levels in renal glomerular, heart and mesentery microvessels were enhanced in the SHR and could also be reduced by Tempol compared to untreated animals (P<0.05). The enhanced MMP-9 levels in SHR microvessels co-express with transcription factors. These results suggest that elevated NF-?B, c-fos and RAR-? expressions and MMP-9 activity in the SHR are superoxide-dependent. PMID:24060804

  12. Controlling quantum-dot light absorption and emission by a surface-plasmon field.

    PubMed

    Huang, Danhong; Easter, Michelle; Gumbs, Godfrey; Maradudin, A A; Lin, Shawn-Yu; Cardimona, D A; Zhang, Xiang

    2014-11-01

    The possibility for controlling both the probe-field optical gain and absorption, as well as photon conversion by a surface-plasmon-polariton near field is explored for a quantum dot located above a metal surface. In contrast to the linear response in the weak-coupling regime, the calculated spectra show an induced optical gain and a triply-split spontaneous emission peak resulting from the interference between the surface-plasmon field and the probe or self-emitted light field in such a strongly-coupled nonlinear system. Our result on the control of the mediated photon-photon interaction, very similar to the 'gate' control in an optical transistor, may be experimentally observable and applied to ultra-fast intrachip/interchip optical interconnects, improvement in the performance of fiber-optic communication networks, and developments of optical digital computers and quantum communications. PMID:25401904

  13. Gaseous emissions from plants in controlled environments

    NASA Technical Reports Server (NTRS)

    Dubay, Denis T.

    1988-01-01

    Plant growth in a controlled ecological life support system may entail the build-up over extended time periods of phytotoxic concentrations of volatile organic compounds produced by the plants themselves. Ethylene is a prominent gaseous emission of plants, and is the focus of this report. The objective was to determine the rate of ethylene release by spring wheat, white potato, and lettuce during early, middle, and late growth stages, and during both the light and dark segments of the diurnal cycle. Plants grown hydroponically using the nutrient film technique were covered with plexiglass containers for 4 to 6 h. At intervals after enclosure, gas samples were withdrawn with a syringe and analyzed for ethylene with a gas chromatograph. Lettuce produced 10 to 100 times more ethylene than wheat or potato, with production rates ranging from 141 to 158 ng g-dry/wt/h. Wheat produced from 1.7 to 14.3 ng g-dry/wt/h, with senescent wheat producing the least amount and flowering wheat the most. Potatoes produced the least amount of ethylene, with values never exceeding 5 ng g-dry/wt/h. Lettuce and potatoes each produced ethylene at similar rates whether in dark period or light period. Ethylene sequestering of 33 to 43 percent by the plexiglass enclosures indicated that these production estimates may be low by one-third to one-half. These results suggest that concern for ethylene build-up in a contained atmosphere should be greatest when growing lettuce, and less when growing wheat or potato.

  14. Response to "Comment on `Frequency-domain stimulated and spontaneous light emission signals at molecular junctions'" [J. Chem. Phys. 142, 137101 (2015)

    NASA Astrophysics Data System (ADS)

    Harbola, Upendra; Agarwalla, Bijay Kumar; Mukamel, Shaul

    2015-04-01

    In a recent work [U. Harbola, B. K. Agrawalla, and S. Mukamel, J. Chem. Phys. 141, 074107 (2014)], we have presented a superoperator (Liouville space) diagrammatic formulation of spontaneous and stimulated optical signals from current-carrying molecular junctions. We computed the diagrams that contribute to the spontaneous light emission SLE (fluorescence and Raman) signal using a diagrammatic method which clearly distinguishes between the Raman and the fluorescence contributions. We pointed out some discrepancies with the work of Galperin, Ratner and Nitzan (GRN) [M. Galperin, M. A. Ratner and, A. Nitzan, J. Chem. Phys. 130, 144109 (2009)]. In their response [M. Galperin, M. A. Ratner and A. Nitzan, "Comment on` Frequency-domain stimulated and spontaneous light emission signals at molecular junctions'" [J. Chem. Phys. 141, 074107 (2014)], J. Chem. Phys. 142, 137101 (2015)] to our work, GRN have argued that there are no differences in the choice of Raman diagrams in both works. Here we reply to their points and show where the differences exist.

  15. Controlled and spontaneous magnetic field generation in a gun-driven spheromak

    SciTech Connect

    Woodruff, S.; Cohen, B.I.; Hooper, E.B.; Mclean, H.S.; Stallard, B.W.; Hill, D.N.; Holcomb, C.T.; Romero-Talamas, C.; Wood, R.D.; Cone, G.; Sovinec, C.R. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); California Institute of Technology, Pasadena, California 91125 (United States); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); University of Wisconsin, Madison, Wisconsin 53706 (United States)

    2005-05-15

    In the Sustained Spheromak Physics Experiment, SSPX [E. B. Hooper, D. Pearlstein, and D. D. Ryutov, Nucl. Fusion 39, 863 (1999)], progress has been made in understanding the mechanisms that generate fields by helicity injection. SSPX injects helicity (linked magnetic flux) from 1 m diameter magnetized coaxial electrodes into a flux-conserving confinement region. Control of magnetic fluctuations ({delta}B/B{approx}1% on the midplane edge) yields T{sub e} profiles peaked at >200 eV. Trends indicate a limiting beta ({beta}{sub e}{approx}4%-6%), and so we have been motivated to increase T{sub e} by operating with stronger magnetic field. Two new operating modes are observed to increase the magnetic field: (A) Operation with constant current and spontaneous gun voltage fluctuations. In this case, the gun is operated continuously at the threshold for ejection of plasma from the gun: stored magnetic energy of the spheromak increases gradually with {delta}B/B{approx}2% and large voltage fluctuations ({delta}V{approx}1 kV), giving a 50% increase in current amplification, I{sub tor}/I{sub gun}. (B) Operation with controlled current pulses. In this case, spheromak magnetic energy increases in a stepwise fashion by pulsing the gun, giving the highest magnetic fields observed for SSPX ({approx}0.7 T along the geometric axis). By increasing the time between pulses, a quasisteady sustainment is produced (with periodic good confinement), comparing well with resistive magnetohydrodynamic simulations. In each case, the processes that transport the helicity into the spheromak are inductive and exhibit a scaling of field with current that exceeds those previously obtained. We use our newly found scaling to suggest how to achieve higher temperatures with a series of pulses.

  16. Comparable vitamin D3 metabolism in the endometrium of patients with recurrent spontaneous abortion and fertile controls.

    PubMed

    Tavakoli, Maryam; Salek-Moghaddam, Alireza; Jeddi-Tehrani, Mahmood; Talebi, Saeed; Kazemi-Sefat, Golnaz-Ensieh; Vafaei, Sedigheh; Mohammadzadeh, Afsaneh; Sheikhhassani, Shahrzad; Zarnani, Amir-Hassan

    2015-05-01

    Vitamin D exerts important roles during pregnancy, and its deficiency may be associated with several pregnancy complications, including pregnancy loss, yet no data are available for molecules involved in vitamin D metabolism in patients with unexplained recurrent spontaneous abortion. In this study, we investigated possible difference in endometrial expression of vitamin D3 receptor (VDR), 1?-hydroxylase (CYP27B1), and 24-hydroxylase (CYP24A1) in women with recurrent spontaneous abortion (n?=?8) and healthy controls (n?=?8). Gene expression of VDR, CYP27B1, and CYP24A1 was determined by real-time PCR, while VDR and CYP27B1 proteins were localized by immunohistochemistry and their abundance was validated by Western blot. We found that both patient and control groups expressed comparable levels of endometrial VDR, CYP27B1, and CYP24A1 transcripts. In line with the gene-expression results, CYP27B1 and different isoforms of VDR protein were present at the same abundance in the endometria of both groups. No significant alteration in VDR and CYP27B1 immunoreactivity pattern was found in the endometrium of patients compared to fertile controls, however. The results of the present study, therefore, do not support the hypothesis of differential expression of key molecules involved in vitamin D3 metabolism in the endometrium of recurrent spontaneous abortion patients and fertile controls. Mol. Reprod. Dev. 82: 356-364, 2015. © 2015 Wiley Periodicals, Inc. PMID:25914243

  17. CONTROLLING NOX EMISSION FROM INDUSTRIAL SOURCES

    EPA Science Inventory

    A number of regulatory actions focused on reducing NOx emissions from stationary combustion sources have been taken in the United States in the last decade. These actions include the Acid Rain NOx regulations, the Ozone Transport Commission's NOx ...

  18. AIR TOXICS EMISSIONS CHARACTERIZATION, CONTROLS & PREVENTION

    EPA Science Inventory

    The goals of this research are to develop improved techniques to characterize hazardous air pollutant emissions from outdoor and indoor sources; use thee techniques to better understand the relative contribution of specific sources to actual human exposure, and identify innovativ...

  19. Temperature Dependence of Factors Controlling Isoprene Emissions

    NASA Technical Reports Server (NTRS)

    Duncan, Bryan N.; Yoshida, Yasuko; Damon, Megan R.; Douglass, Anne R.; Witte, Jacquelyn C.

    2009-01-01

    We investigated the relationship of variability in the formaldehyde (HCHO) columns measured by the Aura Ozone Monitoring Instrument (OMI) to isoprene emissions in the southeastern United States for 2005-2007. The data show that the inferred, regional-average isoprene emissions varied by about 22% during summer and are well correlated with temperature, which is known to influence emissions. Part of the correlation with temperature is likely associated with other causal factors that are temperature-dependent. We show that the variations in HCHO are convolved with the temperature dependence of surface ozone, which influences isoprene emissions, and the dependence of the HCHO column to mixed layer height as OMI's sensitivity to HCHO increases with altitude. Furthermore, we show that while there is an association of drought with the variation in HCHO, drought in the southeastern U.S. is convolved with temperature.

  20. Controls over hydrocarbon emissions from boreal forest conifers

    SciTech Connect

    Lerdau, M.; Litvak, M.; Monson, R. [State Univ. of New York, Stony Brook, NY (United States)]|[Univ. of Colorado, Boulder, CO (United States)

    1995-06-01

    The emissions of monoterpenes and isoprene were measured from two species of conifers native to the boreal forest of Canada, jack pine, Pinus rigida, and black spruce, Picea Mariana. We examined the effects of phenology and needle age on the emissions of these compounds, and the variations in tissue concentrations of monoterpenes. We measured photosynthetic carbon uptake and hydrocarbon emissions at two sites in northern Saskatchewan under controlled light, temperatures, and CO{sub 2} concentrations, and analyzed carbon uptake rates using an infra-red gas analyzer and hydrocarbon emissions using a solid sorbent/thermal desorption system coupled to a gas chromatograph with a mass spectrometer. Our data indicate a strong effect of temperature and seasonality on emissions but only small effects of site conditions. These results suggest that regional models of hydrocarbon emissions from boreal forests should focus on temperature and phenology as the most important controlling variables.

  1. Emission control devices, fuel additive, and fuel composition changes.

    PubMed Central

    Piver, W T

    1977-01-01

    Emission control devices are installed to meet the exhaust standards of the Clean Air Act for carbon monoxide and hydrocarbons, and it is necessary to know, from a public health point of view, how exhaust emissions may be affected by changes in fuel additives and fuel composition. Since these topics are concerned with developing technologies, the available literature on exhaust emission characteristics and the limited information on health effects, is reviewed. PMID:71235

  2. Achieving Acceptable Air Quality: Some Reflections on Controlling Vehicle Emissions

    NASA Astrophysics Data System (ADS)

    Calvert, J. G.; Heywood, J. B.; Sawyer, R. F.; Seinfeld, J. H.

    1993-07-01

    Motor vehicle emissions have been and are being controlled in an effort to abate urban air pollution. This article addresses the question: Will the vehicle exhaust emission control and fuel requirements in the 1990 Clean Air Act Amendments and the California Air Resources Board regulations on vehicles and fuels have a significant impact? The effective control of in-use vehicle emissions is the key to a solution to the motor vehicle part of the urban air pollution problem for the next decade or so. It is not necessary, except perhaps in Southern California, to implement extremely low new car emission standards before the end of the 20th century. Some of the proposed gasoline volatility and composition changes in reformulated gasoline will produce significant reductions in vehicle emissions (for example, reduced vapor pressure, sulfur, and light olefin and improved high end volatility), whereas others (such as substantial oxygenate addition and aromatics reduction) will not.

  3. CONTROL OF MOTOR VEHICLE EMISSIONS - THE U.S. EXPERIENCE

    EPA Science Inventory

    An historical overview of the U.S. experience with controlling emissions from highway motor vehicles is presented. he evolution of new motor vehicle emissions certification practice, end-of-assembly-line inspection, in-use surveillance and recall, inspection and maintenance, and ...

  4. Spray charging and trapping scrubber for particle emission control

    Microsoft Academic Search

    S. Yung; S. Calvert; D. C. Drehmel

    1980-01-01

    The control of fugutive process emissions with a Spray Charging and Trapping scrubber was evaluated both theoretically and experimentally. The technique uses an air curtain and air jet to contain and convey the emissions into a nearby charged spray scrubber. The effects of charge levels on drops and particles, nozzle type, drop size, gas velocity, and liquid\\/gas ratio on collection

  5. Control of variable geometry turbocharged diesel engines for reduced emissions

    Microsoft Academic Search

    A. G. Stefanopoulou; I. Kolmanovsky; J. S. Freudenberg

    1998-01-01

    A multivariable control scheme is designed to minimize emission of nitrogen oxides (NOx) and generation of smoke in a diesel engine equipped with a variable geometry turbocharger (VGT) and an external exhaust gas recirculation system (EGR). Steady-state optimization results in operating points where NOx emissions and smoke generation are highly coupled and require joint management by VGT and EGR actuators

  6. EVALUATION OF MAINTENANCE FOR FUGITIVE VOC EMISSIONS CONTROL

    EPA Science Inventory

    The U.S. EPA Office of Air Quality Planning and Standards (OAQPS) has the responsibility for formulating regulations for the control of fugitive emissions of volatile organic compounds (VOC). 'Fugitive emissions' generally refers to the diffuse release of vaporized hydrocarbon or...

  7. EVALUATION OF EMISSIONS AND CONTROL TECHNOLOGY FOR INDUSTRIAL STOKER BOILERS

    EPA Science Inventory

    The report gives results of a three-phase program to evaluate emissions and control technology for industrial stoker boilers. In Phase I, emission characteristics were determined for a variety of coals fired in a 200-kW stoker boiler. It was observed that significant amounts of s...

  8. 40 CFR 63.325 - Determination of equivalent emission control technology.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Determination of equivalent emission control technology. 63.325 Section 63.325 Protection...Determination of equivalent emission control technology. (a) Any person requesting...illustrating the emission control technology, its operation and integration...

  9. 40 CFR 63.325 - Determination of equivalent emission control technology.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Determination of equivalent emission control technology. 63.325 Section 63.325 Protection...Determination of equivalent emission control technology. (a) Any person requesting...illustrating the emission control technology, its operation and integration...

  10. 40 CFR 63.325 - Determination of equivalent emission control technology.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Determination of equivalent emission control technology. 63.325 Section 63.325 Protection...Determination of equivalent emission control technology. (a) Any person requesting...illustrating the emission control technology, its operation and integration...

  11. 40 CFR 63.325 - Determination of equivalent emission control technology.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Determination of equivalent emission control technology. 63.325 Section 63.325 Protection...Determination of equivalent emission control technology. (a) Any person requesting...illustrating the emission control technology, its operation and integration...

  12. 40 CFR 63.325 - Determination of equivalent emission control technology.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Determination of equivalent emission control technology. 63.325 Section 63.325 Protection...Determination of equivalent emission control technology. (a) Any person requesting...illustrating the emission control technology, its operation and integration...

  13. Low-Emissions Exhaust Quality Control System to Optimize

    E-print Network

    Low-Emissions Exhaust Quality Control System to Optimize DG/CCHP Systems Renewable Energy Research Use (Absorption Chiller, Boiler, others) Exhaust control unit (ExECU) integrated with a prime mover are available for small scale systems, a system to control both temperature and overall flow rate

  14. EUROPEAN ACTIVITIES IN SO2 AND NOX EMISSION CONTROL

    EPA Science Inventory

    The paper gives updated details of major flue gas desulfurization (FGD) and nitrogen oxide (NOx) control installations in the Federal Republic of Germany (West Germany) for coal-fired boilers. The paper reviews applicable government regulations limiting stack emissions, provides ...

  15. A Novel New Approach to VOC and HAP Emission Control 

    E-print Network

    McGinness, M.

    2000-01-01

    HAP (Hazardous Air Pollutant) and VOC (Volatile Organic Compound) thermal emission control devices (ECD) usually require large amounts of energy to operate. They also require large capital investments in heat recovery options and large amounts...

  16. The Control of NOx Emissions from Combustion and Incinerators 

    E-print Network

    Heap, M. P.; Chen, S. L.; Seeker, W. R.; Pershing, D. W.

    1988-01-01

    The effectiveness of combustion modifications, including staged combustion and reburning, for the control of nitrogen oxide emissions from coal fired combustors is most often limited by problems due to carbon burnout or flame impingement. This paper...

  17. A Novel New Approach to VOC and HAP Emission Control

    E-print Network

    McGinness, M.

    VOHAP emissions. Paint spray booth emissions are one of the most problematic sources to control for other VOHAP control technologies. Other applications that will be discussed will involve reducing the need for waste water treatment and disposal... booth air cooling the feed water like a cooling tower unless costly makeup air systems were included to preheat the spray paint booth air. Recent work at Ford Research (Kim, 1998) concluded that activated sludge bioreactors could be used...

  18. Toxic species emissions from controlled combustion of selected paving asphalts 

    E-print Network

    Mendez, Carlos Luis

    1993-01-01

    TOXIC SPECIES EMISSIONS FROM CONTROLLED COMBUSTION OF SELECTED PAVING ASPHALTS A Theis CARLOS LUIS MENDEZ Submitted to the Office of Graduate Studies of Texas Adt, M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1993 Major Subject: Safety Engineering TOXIC SPECIES EMISSIONS FROM CONTROLLED COMBUSTION OF SELECTED PAVING ASPHALTS A Thesis by CARLOS LUIS MENDEZ Submitted to Texas AdtM University in partial fulfillment...

  19. Phase-controlled atom-photon entanglement in a three-level V-type atomic system via spontaneously generated coherence

    E-print Network

    Mohammad Abazari; Ali Mortezapour; Mohammad Mahmoudi; Mostafa Sahrai

    2012-10-12

    We investigate the dynamical behavior of the atom-photon entanglement in a V-type three-level quantum system using the atomic reduced entropy. It is shown that an atom and photons are entangled at the steady-state; however disentanglement can also be achieved in an especial condition. It is demonstrated that in the presence of quantum interference induced by spontaneous emission, the reduced entropy and the atom-photon entanglement are phase-dependent. Non-stationary solution is also obtained when the quantum interference due to the spontaneous emission is completely included.

  20. Pump-Controlled Directional Light Emission from Random Lasers

    NASA Astrophysics Data System (ADS)

    Hisch, Thomas; Liertzer, Matthias; Pogany, Dionyz; Mintert, Florian; Rotter, Stefan

    2013-07-01

    The angular emission pattern of a random laser is typically very irregular and difficult to tune. Here we show by detailed numerical calculations that one can overcome the lack of control over this emission pattern by actively shaping the spatial pump distribution. We demonstrate, in particular, how to obtain customized pump profiles to achieve highly directional emission. Going beyond the regime of strongly scattering media where localized modes with a given directionality can simply be selected by the pump, we present an optimization-based approach which shapes extended lasing modes in the weakly scattering regime according to any predetermined emission pattern.

  1. Wavefront analysis of nonlinear self-amplified spontaneous-emission free-electron laser harmonics in the single-shot regime.

    PubMed

    Bachelard, R; Mercère, P; Idir, M; Couprie, M-E; Labat, M; Chubar, O; Lambert, G; Zeitoun, Ph; Kimura, H; Ohashi, H; Higashiya, A; Yabashi, M; Nagasono, M; Hara, T; Ishikawa, T

    2011-06-10

    The single-shot spatial characteristics of the vacuum ultraviolet self-amplified spontaneous emission of a free electron laser (FEL) is measured at different stages of amplification up to saturation with a Hartmann wavefront sensor. We show that the fundamental radiation at 61.5 nm tends towards a single-mode behavior as getting closer to saturation. The measurements are found in good agreement with simulations and theory. A near diffraction limited wavefront was measured. The analysis of Fresnel diffraction through the Hartmann wavefront sensor hole array also provides some further insight for the evaluation of the FEL transverse coherence, of high importance for various applications. PMID:21770510

  2. Wavefront Analysis of Nonlinear Self-Amplified Spontaneous-Emission Free-Electron Laser Harmonics in the Single-Shot Regime

    NASA Astrophysics Data System (ADS)

    Bachelard, R.; Mercère, P.; Idir, M.; Couprie, M.-E.; Labat, M.; Chubar, O.; Lambert, G.; Zeitoun, Ph.; Kimura, H.; Ohashi, H.; Higashiya, A.; Yabashi, M.; Nagasono, M.; Hara, T.; Ishikawa, T.

    2011-06-01

    The single-shot spatial characteristics of the vacuum ultraviolet self-amplified spontaneous emission of a free electron laser (FEL) is measured at different stages of amplification up to saturation with a Hartmann wavefront sensor. We show that the fundamental radiation at 61.5 nm tends towards a single-mode behavior as getting closer to saturation. The measurements are found in good agreement with simulations and theory. A near diffraction limited wavefront was measured. The analysis of Fresnel diffraction through the Hartmann wavefront sensor hole array also provides some further insight for the evaluation of the FEL transverse coherence, of high importance for various applications.

  3. Amplified spontaneous emission of 3-(1,1-dicyanoethenyl)-1-phenyl-4,5-dihydro-1H-pyrazole molecule embedded in various polymer matrices

    NASA Astrophysics Data System (ADS)

    Mysliwiec, Jaroslaw; Sznitko, Lech; Szukalski, Adam; Parafiniuk, Kacper; Bartkiewicz, Stanislaw; Miniewicz, Andrzej; Sahraoui, Bouchta; Rau, Ileana; Kajzar, Francois

    2012-08-01

    Results of studies on the amplified spontaneous emission (ASE) phenomenon in 3-(1,1-dicyanoethenyl)-1-phenyl-4,5-dihydro-1H-pyrazole (DCNP) molecules in four different polymeric matrices are reported. We have analyzed ASE spectra coming from thin films of DCNP-matrix samples when excited by the Nd:YAG nanosecond pulsed laser doubled in frequency (? = 532 nm). We report on ASE characteristics in function of different excitation pulse energy densities evaluating ASE thresholds, exponential gain coefficients and reporting the influence of the specific matrix-dye interactions on the photo-degradation process of the dye.

  4. Raman-shifted KrF laser radiation with low amplified spontaneous emission for a rotational Raman daytime-temperature lidar

    SciTech Connect

    Luckow, F.; Voss, E.; Zeyn, J.; Lahmann, W.; Weitkamp, C.; Michaelis, W. (Institut fuer Physik, GKSS-Forschungszentrum Geesthacht GmbH, D-21502 Geesthacht (Germany))

    1994-07-15

    Various configurations of a tunable two-stage KrF laser have been investigated for providing powerful laser pulses with very low amplified spontaneous emission (ASE). The lowest fraction (0.00017%) of ASE was attained with a single-pass amplifier and a phase-conjugate Brillouin mirror. The most suitable application envisaged for the laser source, i.e., remote daytime-temperature measurement by means of rotational Raman scattering, is a dedicated oscillator--amplifier configuration with an ASE of 0.005% at an output of 300 mJ. The very low values of ASE were measured with the aid of a thallium atomic-vapor filter.

  5. Wideband thulium-holmium-doped fiber source with combined forward and backward amplified spontaneous emission at 1600-2300??nm spectral band.

    PubMed

    Honzatko, Pavel; Baravets, Yauhen; Kasik, Ivan; Podrazky, Ondrej

    2014-06-15

    We have experimentally demonstrated two extremely wideband amplified spontaneous emission (ASE) sources. High bandwidth is achieved by combining the backward and forward ASEs generated in thulium-holmium-doped fiber using appropriate wideband couplers. The ASE source optimized for flat spectral power density covers a spectral range from 1527 to 2171 nm at a -10??dB level. The ASE source optimized for spectroscopy features an enhancement with respect to single-mode fiber (SMF) coupled halogen lamps within the spectral range from 1540 nm to more than 2340 nm covering the 800 nm bandwidth. PMID:24978559

  6. Emission current control system for multiple hollow cathode devices

    NASA Technical Reports Server (NTRS)

    Beattie, John R. (Inventor); Hancock, Donald J. (Inventor)

    1988-01-01

    An emission current control system for balancing the individual emission currents from an array of hollow cathodes has current sensors for determining the current drawn by each cathode from a power supply. Each current sensor has an output signal which has a magnitude proportional to the current. The current sensor output signals are averaged, the average value so obtained being applied to a respective controller for controlling the flow of an ion source material through each cathode. Also applied to each controller are the respective sensor output signals for each cathode and a common reference signal. The flow of source material through each hollow cathode is thereby made proportional to the current drawn by that cathode, the average current drawn by all of the cathodes, and the reference signal. Thus, the emission current of each cathode is controlled such that each is made substantially equal to the emission current of each of the other cathodes. When utilized as a component of a multiple hollow cathode ion propulsion motor, the emission current control system of the invention provides for balancing the thrust of the motor about the thrust axis and also for preventing premature failure of a hollow cathode source due to operation above a maximum rated emission current.

  7. Controlling NOx emission from industrial sources

    Microsoft Academic Search

    R. K. Srivastava; W. Nueffer; D. Grano; S. Khan; J. E. Staudt; W. Jozewicz

    2005-01-01

    A number of regulatory actions focused on reducing NOx emissions from stationary combustion sources have been taken in the United States in the last decade. These actions include the Acid Rain NOx regulations, the Ozone Transport Commission's NOx Budget Program, and the NOx SIP Call rulemakings. In addition to these regulations, the recent Interstate Air Quality Rulemaking proposal and other

  8. Genetic Control of Spontaneous Arthritis in a Four-Way Advanced Intercross Line

    PubMed Central

    Ranea, Laura Mellado; de Castro Marques, Andreia; Möller, Steffen; Gupta, Yask; Ibrahim, Saleh M.

    2013-01-01

    Identifying the genetic basis of complex diseases, such as rheumatoid arthritis, remains a challenge that requires experimental models to reduce the genetic and environmental variability. Numerous loci for arthritis have been identified in induced animal models; however, few spontaneous models have been genetically studied. Therefore, we generated a four-way advanced intercross line (AIL) from four inbred strains, including BXD2/TyJ which spontaneously develops autoimmune arthritis. A genome-wide scan for spontaneous arthritis was performed in a cohort of 366 mice of the fourth generation (G4) of this cross. Five loci contributing to clinical phenotypes were identified in chromosomes 3, 7, 13, 18, and X. Three of the loci found in this study, confirm previously identified loci; whereas two of them are novel loci. Interesting candidate genes for the loci are highlighted. This study provides a genetic overview of spontaneous arthritis in mice and aids to solve the genetic etiology of rheumatoid arthritis and to gain a better understanding of the disease. PMID:24146764

  9. Using Transfer of Stimulus Control Technology to Promote Generalization and Spontaneity of Language

    ERIC Educational Resources Information Center

    Spencer, Trina D.; Higbee, Thomas S.

    2012-01-01

    Children with autism often use newly acquired language in restricted contexts and with limited variability. Instructional tactics that embed generalization technology have shown promise for increasing spontaneity, response variation, and the generalized use of language across settings, people, and materials. In this study, we explored the…

  10. Control of Variable Geometry Turbocharged Diesel Engines for Reduced Emissions

    E-print Network

    Stefanopoulou, Anna

    Control of Variable Geometry Turbocharged Diesel Engines for Reduced Emissions A.G. Stefanopoulouz Introduction In this paper we consider an automotive control problem for a variable geometry turbocharged (VGT torque output as compared to (non-turbocharged) naturally aspirated engines 13]. The power generated

  11. CONTROL OF PARTICULATE EMISSIONS IN THE PRIMARY NONFERROUS METALS INDUSTRIES

    EPA Science Inventory

    The purpose of the symposium on 'Control of Particulate Emissions in the Primary Nonferrous Metals Industries' was to provide a forum for the exchange of knowledge and new ideas on particulate control technology with emphasis on industrial applications of environmental particulat...

  12. A quantum dot single-photon source with on-the-fly all-optical polarization control and timed emission

    E-print Network

    Dirk Heinze; Artur Zrenner; Stefan Schumacher

    2014-12-02

    Sources of single photons are key elements in the study of basic quantum optical concepts and applications in quantum information science. Among the different sources available, semiconductor quantum dots excel with their straight forward integrability in semiconductor based on-chip solutions and the potential that photon emission can be triggered on demand. Usually, the photon emission event is part of a cascaded biexciton-exciton emission scheme. Important properties of the emitted photon such as polarization and time of emission are either probabilistic in nature or pre-determined by electronic properties of the system. In this work, we study the direct two-photon emission from the biexciton. We show that emission through this higher-order transition provides a much more versatile approach to generate a single photon. In the scheme we propose, the two-photon emission from the biexciton is enabled by a laser field (or laser pulse) driving the system into a virtual state inside the band gap. From this intermediate virtual state, the single photon of interest is then spontaneously emitted. Its properties are determined by the driving laser pulse, enabling all-optical on-the-fly control of polarization state, frequency, and time of emission of the photon.

  13. Modeling study of natural emissions, source apportionment, and emission control of atmospheric mercury

    NASA Astrophysics Data System (ADS)

    Shetty, Suraj K.

    Mercury (Hg) is a toxic pollutant and is important to understand its cycling in the environment. In this dissertation, a number of modeling investigations were conducted to better understand the emission from natural surfaces, the source-receptor relationship of the emissions, and emission reduction of atmospheric mercury. The first part of this work estimates mercury emissions from vegetation, soil and water surfaces using a number of natural emission processors and detailed (LAI) Leaf Area Index data from GIS (Geographic Information System) satellite products. East Asian domain was chosen as it contributes nearly 50% of the global anthropogenic mercury emissions into the atmosphere. The estimated annual natural mercury emissions (gaseous elemental mercury) in the domain are 834 Mg yr-1 with 462 Mg yr-1 contributing from China. Compared to anthropogenic sources, natural sources show greater seasonal variability (highest in simmer). The emissions are significant, sometimes dominant, contributors to total mercury emission in the regions. The estimates provide possible explanation for the gaps between the anthropogenic emission estimates based on activity data and the emission inferred from field observations in the regions. To understand the contribution of domestic emissions to mercury deposition in the United States, the second part of the work applies the mercury model of Community Multi-scale Air Quality Modeling system (CMAQ-Hg v4.6) to apportion the various emission sources attributing to the mercury wet and dry deposition in the 6 United States receptor regions. Contributions to mercury deposition from electric generating units (EGU), iron and steel industry (IRST), industrial point sources excluding EGU and IRST (OIPM), the remaining anthropogenic sources (RA), natural processes (NAT), and out-of-boundary transport (BC) in domain was estimated. The model results for 2005 compared reasonably well to field observations made by MDN (Mercury Deposition Network) and CAMNet (Canadian Atmospheric Mercury Measurement Network). The model estimated a total deposition of 474 Mg yr-1 to the CONUS (Contiguous United States) domain, with two-thirds being dry deposited. Reactive gaseous mercury contributed the most to 60% of deposition. Emission speciation distribution is a key factor for local deposition as contribution from large point sources can be as high as 75% near (< 100 km) the emission sources, indicating that emission reduction may result in direct deposition decrease near the source locations. Among the sources, BC contributes to about 68% to 91% of total deposition. Excluding the BC's contribution, EGU contributes to nearly 50% of deposition caused by CONUS emissions in the Northeast, Southeast and East Central regions, while emissions from natural processes are more important in the Pacific and West Central regions (contributing up to 40% of deposition). The modeling results implies that implementation of the new emission standards proposed by USEPA (United States Environmental Protection Agency) would significantly benefit regions that have larger contributions from EGU sources. Control of mercury emissions from coal combustion processes has attracted great attention due to its toxicity and the emission-control regulations and has lead to advancement in state-of-the-art control technologies that alleviate the impact of mercury on ecosystem and human health. This part of the work applies a sorption model to simulate adsorption of mercury in flue gases, onto a confined-bed of activated carbon. The model's performances were studied at various flue gas flow rates, inlet mercury concentrations and adsorption bed temperatures. The process simulated a flue gas, with inlet mercury concentration of 300 ppb, entering at a velocity of 0.3 m s-1 from the bottom into a fixed bed (inside bed diameter of 1 m and 3 m bed height; bed temperature of 25 °C) of activated carbon (particle size of 0.004 m with density of 0.5 g cm-3 and surface area of 90.25 cm2 g -1). The model result demonstrated that a batch of activated carbon

  14. Acoustic emission feedback control for control of boiling in a microwave oven

    DOEpatents

    White, Terry L. (Oak Ridge, TN)

    1991-01-01

    An acoustic emission based feedback system for controlling the boiling level of a liquid medium in a microwave oven is provided. The acoustic emissions from the medium correlated with surface boiling is used to generate a feedback control signal proportional to the level of boiling of the medium. This signal is applied to a power controller to automatically and continuoulsly vary the power applied to the oven to control the boiling at a selected level.

  15. Cardiovascular effects of halothane anesthesia after diazepam and ketamine administration in beavers (Castor canadensis) during spontaneous or controlled ventilation.

    PubMed

    Greene, S A; Keegan, R D; Gallagher, L V; Alexander, J E; Harari, J

    1991-05-01

    Fourteen adult beavers (Castor canadensis) weighing 16.5 +/- 4.14 kg (mean +/- SD) were anesthetized for surgical implantation of radio telemetry devices. Beavers were anesthetized with diazepam (0.1 mg/kg) and ketamine (25 mg/kg) administered IM, which provided smooth anesthetic induction and facilitated tracheal intubation. Anesthesia was maintained with halothane in oxygen via a semiclosed circle anesthetic circuit. Values for heart rate, respiratory rate, esophageal temperature, direct arterial blood pressure, end-tidal halothane concentration, and end-tidal CO2 tension were recorded every 15 minutes during the surgical procedure. Arterial blood samples were collected every 30 minutes to determine pH, PaO2, and PaCO2. Values for plasma bicarbonate, total CO2, and base excess were calculated. Ventilation was spontaneous in 7 beavers and controlled to maintain normocapnia (PaCO2 approx 40 mm of Hg) in 7 others. Vaporizer settings were adjusted to maintain a light surgical plane of anesthesia. Throughout the surgical procedure, all beavers had mean arterial pressure less than 60 mm of Hg and esophageal temperature less than 35 C. Mean values for arterial pH, end-tidal CO2, PaO2, and PaCO2 were significantly (P less than 0.05) different in spontaneously ventilating beavers, compared with those in which ventilation was controlled. Respiratory acidosis during halothane anesthesia was observed in spontaneously ventilating beavers, but not in beavers maintained with controlled ventilation. All beavers recovered unremarkably from anesthesia. PMID:1906691

  16. Emission control cost-effectiveness of alternative-fuel vehicles

    Microsoft Academic Search

    Q. Wang; D. Sperling; J. Olmstead

    1993-01-01

    Although various legislation and regulations have been adopted to promote the use of alternative-fuel vehicles for curbing urban air pollution problems, there is a lack of systematic comparisons of emission control cost-effectiveness among various alternative-fuel vehicle types. In this paper, life-cycle emission reductions and life-cycle costs were estimated for passenger cars fueled with methanol, ethanol, liquefied petroleum gas, compressed natural

  17. Control of mercury vapor emissions from combustion flue gas

    Microsoft Academic Search

    Rong Yan; David Tee Liang; Joo Hwa Tay

    2003-01-01

    Goal, Scope and Background  Mercury (Hg) emission from combustion flue gas is a significant environmental concern due to its toxicity and high volatility.\\u000a A number of the research efforts have been carried out in the past decade exploiting mercury emission, monitoring and control\\u000a from combustion flue gases. Most recently, increasing activities are focused on evaluating the behavior of mercury in coal

  18. A plasma process controlled emissions off-gas demonstration

    SciTech Connect

    Battleson, D.; Kujawa, S.T. [MSE, Inc., Butte, MT (United States); Leatherman, G. [SAIC, Inc., Idaho Falls, ID (United States). STAR Center

    1995-12-31

    Thermal technologies are currently identified as playing an important role in the treatment of many DOE waste streams, and emissions from these processes will be scrutinized by the public, regulators, and stakeholders. For some time, there has been a hesitancy by the public to accept thermal treatment of radioactive contaminated waste because of the emissions from these processes. While the technology for treatment of emissions from these processes is well established, it is not possible to provide the public complete assurance that the system will be in compliance with air quality regulations 100% of the operating time in relation to allowing noncompliant emissions to exit the system. Because of the possibility of noncompliant emissions and the public`s concern over thermal treatment systems, it has been decided that the concept of a completely controlled emissions off-gas system should be developed and implemented on Department of Energy (DOE) thermal treatment systems. While the law of conservation of mass precludes a completely closed cycle system, it is possible to apply the complete control concept to emissions.

  19. Anthropogenic mercury flows in India and impacts of emission controls.

    PubMed

    Burger Chakraborty, Laura; Qureshi, Asif; Vadenbo, Carl; Hellweg, Stefanie

    2013-08-01

    India is a major emitter of mercury, a pollutant of global importance. However, quantitative information on mercury flows in the country is lacking. Here, we quantify major transfer pathways for anthropogenic mercury, its emissions to the environment (air, water, soil), and storage in consumer products and anthropogenic sinks (e.g., landfills) in India in the period 2001-2020, and evaluate the potential influence of six pollution control measures. Total mercury emissions in India were approximately 415 tonnes in 2001, 310 tonnes in 2010, and are projected to rise to 540 tonnes in 2020. In 2010, 76% of these emissions went to the atmosphere. The most important emission sources to atmosphere are coal power plants and zinc production. Pesticides were the most important source for emissions to soil in 2005 and dental amalgam in later years. Mercury stocks in products rose from 700 tonnes in 2001 to 1125 tonnes in 2010, and in landfills and ash-made structures (e.g., embankments) from 920 tonnes in 2001 to 1450 tonnes in 2010. These stocks are expected to rise further and may be regarded as stored toxicity, which may become a concern in the future. Total mercury emissions can be reduced by about 50% by combining pollution control measures that target different mercury emission sources. PMID:23834017

  20. Method and apparatus for emission control

    SciTech Connect

    Kempf, T.W.; Corcoran, R.F.; Sikora, D.

    1992-01-01

    The invention includes process and apparatus for removing pollutants from a gas including fluidizing a bed of particles in a container, introducing a gas containing pollutant into the bed, removing the pollutant through deposition on the particles, controlling temperatures in the container by injecting coolant fluid through a coolant nozzle, and reducing clogging or fouling on the coolant nozzle. The process and apparatus includes controlling temperatures in the container within narrowly specified ranges of temperatures and providing a constant pressure of coolant fluid and constant pressure of purge gas to the coolant nozzle such that interchangeable selection made between the coolant fluid and purge gas in a time period sufficiently short provides accurate temperature control and reduces clogging or fouling on the coolant nozzle.

  1. Mercury emissions control technologies for mixed waste thermal treatment

    SciTech Connect

    Chambers, A.; Knecht, M.; Soelberg, N.; Eaton, D. [Lockheed Martin Idaho Technologies Co., Idaho Falls, ID (United States). Idaho National Engineering and Environmental Lab.; Roberts, D.; Broderick, T. [ADA Technologies, Englewood, CO (United States)

    1997-12-31

    EPA has identified wet scrubbing at low mercury feedrates, as well as carbon adsorption via carbon injection into the offgas or via flow through fixed carbon beds, as control technologies that can be used to meet the proposed Maximum Achievable Control Technology (MACT) rule limit for mercury emissions from hazardous waste incinerators. DOE is currently funding demonstrations of gold amalgamation that may also control mercury to the desired levels. Performance data from a variety of sources was reviewed to determine ranges of achievable mercury control. Preliminary costs were estimated for using these technologies to control mercury emissions from mixed waste incineration. Mercury emissions control for mixed waste incineration may need to be more efficient than for incineration of other hazardous wastes because of higher mercury concentrations in some mixed waste streams. However, mercury control performance data for wet scrubbing and carbon adsorption is highly variable. More information is needed to demonstrate control efficiencies that are achievable under various design and operating conditions for wet scrubbing, carbon adsorption, and gold amalgamation technologies. Given certain assumptions made in this study, capital costs, operating costs, and lifecycle costs for carbon injection, carbon beds, and gold amalgamation generally vary for different assumed mercury feedrates and for different offgas flowrates. Assuming that these technologies can in fact provide the necessary mercury control performance, each of these technologies may be less costly than the others for certain mercury feedrates and the offgas flowrates.

  2. New emission controls for Missouri batch-type charcoal kilns

    SciTech Connect

    Yronwode, P.; Graf, W.J.

    1999-07-01

    Charcoal kilns have been exempted from air emission regulation in the state of Missouri. Today, 80% of US charcoal production takes place in Missouri. As a result of a petition filed by people in the area around an installation in southern Missouri, the US Environmental Protection Agency (EPA) set up air monitors and measured ambient air levels at that charcoal manufacturing installation. These monitors yielded the highest particulate matter less than 10 micron (PM{sub 10}) levels ever recorded in the state. Earlier stack testing at another charcoal manufacturing installation indicated that toxics and carcinogens are present in charcoal kiln air emissions. A Charcoal Kiln Workgroup was formed to determine the Best Available Control Technology (BACT) for charcoal kilns and to draft a charcoal kiln rule that requires BACT. The BACT report determined that afterburners were suitable for controlling emissions from batch-type charcoal kilns. In addition, the charcoal industry supported incorporating the BACT limits and requirements into an enforceable state rule and submitting this rule to the EPA for federal approval. A consent agreement between the EPA and three major charcoal companies was signed with provisions to install, operate, and maintain emission control devices on charcoal kilns. This agreement was to settle complaints alleging that the three major charcoal producers had failed to report toxic air emissions to federal and state regulators. The agreement provided that industry would install control devices on a set schedule with some charcoal kilns being shut down.

  3. Coal-fueled diesel technology development Emissions Control

    SciTech Connect

    Van Kleunen, W.; Kaldor, S.; Gal, E.; Mengel, M.; Arnold, M.

    1994-01-01

    GEESI Emissions Control program activity ranged from control concept testing of 10 CFM slipstream from a CWS fuel single cylinder research diesel engine to the design, installation, and operation of a full-size Emissions Control system for a full-size CWS fuel diesel engine designed for locomotive operation.Early 10 CFM slipstream testing program activity was performed to determine Emissions Characteristics and to evaluate Emissions Control concepts such a Barrier filtration, Granular bed filtration, and Cyclone particulate collection for reduction of particulate and gaseous emissions. Use of sorbent injection into the engine exhaust gas upstream of the barrier filter or use of sorbent media in the granular bed filter were found to provide reduction of exhaust gas SO{sub 2} and NO{sub x} in addition to collection of ash particulate. Emergence of the use of barrier filtration as a most practical Emissions Control concept disclosed a need to improve cleanability of the filter media in order to avoid reduction of turbocharger performance by excessive barrier filter pressure drop. The next progression of program activity, after the slipstream feasibility state, was 500 CFM cold flow testing of control system concepts. The successful completion of 500 CFM cold flow testing of the Envelope Filter led to a subsequent progression to a similar configuration Envelope Filter designed to operate at 500 CFM hot gas flow from the CWS fuel research diesel engine in the GETS engine test laboratory. This Envelope Filter included the design aspect proven by cold flow testing as well as optimization of the selection of the installed filter media.

  4. Soil acidification in China: is controlling SO2 emissions enough?

    PubMed

    Zhao, Yu; Duan, Lei; Xing, Jia; Larssen, Thorjorn; Nielsen, Chris P; Hao, Jiming

    2009-11-01

    Facing challenges of increased energy consumption and related regional air pollution, China has been aggressively implementing flue gas desulfurization (FGD) and phasing out small inefficient units in the power sector in order to achieve the national goal of 10% reduction in sulfur dioxide (SO(2)) emissions from 2005 to 2010. In this paper, the effect of these measures on soil acidification is explored. An integrated methodology is used, combining emission inventory data, emission forecasts, air quality modeling, and ecological sensitivities indicated by critical load. National emissions of SO(2), oxides of nitrogen (NO(X)), particulate matter (PM), and ammonia (NH(3)) in 2005 were estimated to be 30.7, 19.6, 31.3, and 16.6 Mt, respectively. Implementation of existing policy will lead to reductions in SO(2) and PM emissions, while those of NO(X) and NH(3) will continue to rise, even under tentatively proposed control measures. In 2005, the critical load for soil acidification caused by sulfur (S) deposition was exceeded in 28% of the country's territory, mainly in eastern and south-central China. The area in exceedance will decrease to 26% and 20% in 2010 and 2020, respectively, given implementation of current plans for emission reductions. However, the exceedance of the critical load for nitrogen (N, combining effects of eutrophication and acidification) will double from 2005 to 2020 due to increased NO(X) and NH(3) emissions. Combining the acidification effects of S and N, the benefits of SO(2) reductions during 2005-2010 will almost be negated by increased N emissions. Therefore abatement of N emissions (NO(X) and NH(3)) and deposition will be a major challenge to China, requiring policy development and technology investments. To mitigate acidification in the future, China needs a multipollutant control strategy that integrates measures to reduce S, N, and PM. PMID:19924917

  5. Pronounced Purcell enhancement of spontaneous emission in CdTe/ZnTe quantum dots embedded in micropillar cavities

    E-print Network

    Jakubczyk, Tomasz; Smole?ski, Tomasz; Golnik, Andrzej; Florian, Matthias; Jahnke, Frank; Kruse, Carsten; Hommel, Detlef; Kossacki, Piotr

    2012-01-01

    The coupling of CdTe/ZnTe quantum dot (QD) emission to micropillar cavity eigenmodes in the weak coupling regime is demonstrated. We analyze photoluminescence spectra of QDs embedded in monolithic micropillar cavities based on Bragg mirrors which contain MgSe/ZnTe/MgTe superlattices as low-index material. The pillar emission shows pronounced cavity eigenmodes and their spectral shape is in good agreement with simulations. QD emission in resonance with the cavity mode is shown to be efficiently guided toward the detector and an experimental Purcell enhancement by a factor of 5.7 is determined, confirming theoretical expectations.

  6. Controlling formaldehyde emissions with boiler ash.

    PubMed

    Cowan, Jennifer; Abu-Daabes, Malyuba; Banerjee, Sujit

    2005-07-01

    Fluidized wood ash reduces formaldehyde in air from about 20 to <1 ppmv. Methanol is removed to a much lower extent. The efficiency of formaldehyde reduction increases with increasing moisture content of the ash. Sorption of formaldehyde to ash can be substantially accounted for by partitioning to the water contained in the ash followed by rate-controlling binding to the ash solids. Adsorption occurs at temperatures of up to 165 degrees C; oxidation predominates thereafter. It is proposed that formaldehyde could be stripped from an air stream in a fluidized bed containing ash, which could then be returned to a boiler to incinerate the formaldehyde. PMID:16053116

  7. Enhanced control of mercury emissions through modified speciation

    SciTech Connect

    Livengood, C.D.; Mendelsohn, M.H.

    1997-07-01

    In anticipation of possible regulations regarding mercury emissions, research efforts sponsored by DOE, EPRI, and others are investigating the risks posed by mercury emissions, improved techniques for measuring those emissions, and possible control measures. The focus in the control research is on techniques that can be used in conjunction with existing flue-gas-cleanup (FGC) systems in order to minimize additional capital costs and operational complexity. Argonne National Laboratory has supported the DOE Fossil Energy Program for over 15 years with research on advanced environmental control technologies. The emphasis in Argonne`s work has been on integrated systems that combine control of several pollutants. Specific topics have included spray drying for sulfur dioxide and particulate-matter control with high-sulfur coal, combined sulfur dioxide and nitrogen oxides control technologies, and techniques to enhance mercury control in existing FGC systems. The latter area has focused on low-cost dry sorbents for use with fabric filters or electrostatic precipitators and techniques for improving the capture of mercury in wet flue-gas desulfurization (FGD) systems. This paper presents results from recent work that has studied the effects of several oxidizing agents in combination with typical flue-gas species (e.g., nitrogen oxides and sulfur dioxide) on the oxidation of Hg{sup 0}.

  8. Modeling the benefits of power plant emission controls in Massachusetts.

    PubMed

    Levy, Jonathan I; Spengler, John D

    2002-01-01

    Older fossil-fueled power plants provide a significant portion of emissions of criteria air pollutants in the United States, in part because these facilities are not required to meet the same emission standards as new sources under the Clean Air Act. Pending regulations for older power plants need information about any potential public health benefits of emission reductions, which can be estimated by combining emissions information, dispersion modeling, and epidemiologic evidence. In this article, we develop an analytical modeling framework that can evaluate health benefits of emission controls, and we apply our model to two power plants in Massachusetts. Using the CALPUFF atmospheric dispersion model, we estimate that use of Best Available Control Technology (BACT) for NOx and SO2 would lead to maximum annual average secondary particulate matter (PM) concentration reductions of 0.2 microg/m3. When we combine concentration reductions with current health evidence, our central estimate is that the secondary PM reductions from these two power plants would avert 70 deaths per year in a population of 33 million individuals. Although benefit estimates could differ substantially with different interpretations of the health literature, parametric perturbations within CALPUFF and other simple model changes have relatively small impacts from an aggregate risk perspective. While further analysis would be required to reduce uncertainties and expand on our analytical model, our framework can help decision-makers evaluate the magnitude and distribution of benefits under different control scenarios. PMID:15152660

  9. Environmental controls on Pan-Arctic wetland methane emissions

    NASA Astrophysics Data System (ADS)

    Chen, Xiaodong; Bohn, Theodore; Lettenmaier, Dennis

    2015-04-01

    Environmental conditions such as soil temperature and moisture, incident solar radiation, and atmospheric carbon dioxide concentration are important environmental controls on methane emissions from northern wetlands. We investigated the spatio-temporal distributions of influence of these factors over northern wetland methane emissions via the Variable Infiltration Capacity (VIC) model. We simulated methane emissions from wetlands across the Pan-Arctic domain over the period 1948-2006, with annual average emissions of 35.1±6.7 TgCH4/year. From control simulations that each held one environmental factor constant, we characterized sensitivities to air temperature, precipitation, incident long- and short-wave radiation, and atmospheric [CO2] as a function of average summer air temperature and precipitation. Trade-offs between air temperature and precipitation caused maximal emissions to occur along a line in precipitation-temperature space with a slope of approximately 13 mm month-1 / K, leading to separation of wetlands into various combinations of water-limited and temperature-limited regimes. Emissions from relatively warm and dry wetlands in the southern (permafrost-free) portion of the domain tended to be positively correlated with precipitation and negatively correlated with air temperature, while emissions from wetter and colder wetlands further north (permafrost) tended to be positively correlated with air temperature. Over the period 1960-2006, emissions increased by 20%, over 90% of which can be attributed to climate change, with summer air temperatures explaining the majority of the variance. We estimated future emissions in response to CMIP5 model projections under the RCP4.5 scenario via two methods: (1) the VIC model and (2) the temperature- and precipitation-dependent sensitivities computed from the historical simulation. The two methods yielded similar projections of emissions, with end-of-century emissions at 142% of present-day levels, accompanied by an expansion of the area of water-limited wetlands. Both the magnitude of the increase in emissions and the widespread drying of wetlands are corroborated by other recent process-based studies.

  10. The disrupted basal ganglia and behavioural control: an integrative cross-domain perspective of spontaneous stereotypy.

    PubMed

    McBride, Sebastian D; Parker, Matthew O

    2015-01-01

    Spontaneous stereotypic behaviour (SB) is common in many captive animal species, as well as in humans with some severe psychiatric disorders, and is often cited as being related to general basal ganglia dysfunction. Despite this assertion, there is little in the literature examining SB specifically in terms of the basal ganglia mechanics. In this review, we attempt to fill this gap by offering an integrative, cross-domain perspective of SB by linking what we currently understand about the SB phenotype with the ever-growing literature on the anatomy and functionality of the basal ganglia. After outlining current models of SB from different theoretical perspectives, we offer a broad but detailed overview of normally functioning basal ganglia mechanics, and attempt to link this with current neurophysiological evidence related to spontaneous SB. Based on this we present an empirically derived theoretical framework, which proposes that SB is the result of a dysfunctional action selection system that may reflect dysregulation of excitatory (direct) and inhibitory (indirect and hyperdirect) pathways as well as alterations in mechanisms of behavioural switching. This approach also suggests behaviours that specifically become stereotypic may reflect inbuilt low selection threshold behavioural sequences associated with early development and the species-specific ethogram or, low threshold behavioural sequences that are the result of stress-induced dopamine exposure at the time of performance. PMID:25052167

  11. Emissions, combustion dynamics, and control of a multiple swirl combustor

    NASA Astrophysics Data System (ADS)

    Li, Guoqiang

    To achieve single digit NOx emission from gas turbine combustors and prevent the combustion dynamics encountered in Lean Premixed Combustion, it is essential to understand the correlations among emission characteristics, combustion dynamics, and dynamics and characteristics of swirling flow field. The focus of this dissertation is to investigate the emission characteristics and combustion dynamics of multiple swirl dump combustors either in premixing or non-premixed combustion (e.g. Lean Direct Injection), and correlate these combustion characteristics (emissions, combustion instability and lean flammability) to the fluids dynamics (flow structures and its evolution). This study covers measurement of velocity flow field, temperature field, and combustion under effects of various parameters, including inlet flow Reynolds number, inlet air temperature, swirl configurations, downstream exhaust nozzle contraction ratios, length of mixing tube. These parameters are tested in both liquid and gaseous fuel combustions. Knowledge obtained through this comprehensive study is applied to passive and active controls for improving gas turbine combustion performance in the aid of novel sensor and actuator technologies. Emissions and combustion characteristics are shown closely related to the shape and size of central recirculation zone (CRZ), the mean and turbulence velocity and strain rate, and dynamics of large vortical structures. The passive controls, mostly geometry factors, affect the combustion characteristics and emissions through their influences on flow fields, and consequently temperature and radical fields. Air assist, which is used to adjust the momentum of fuel spray, is effective in reducing NOx and depress combustion oscillation without hurting LBO. Fuel distribution/split is also one important factor for achieving low NOx emission and control of combustion dynamics. The dynamics of combustion, including flame oscillations close to LBO and acoustic combustion instability, can be characterized by OH*/CH* radical oscillations and phase-locked chemiluminescence imaging. The periodic fluctuation of jet velocity and formation of large vortical structures within CRZ are responsible for combustion instability in multiple swirl combustors.

  12. 78 FR 36776 - Proposed Information Collection Request; Comment Request; Emission Control System Performance...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-19

    ...Request; Comment Request; Emission Control System Performance Warranty Regulations...request (ICR), ``Emission Control System Performance Warranty Regulations...EPA ICR No. 0116.10, OMB Control No. 2060-0060) to the...

  13. Amplified spontaneous emission in polymethyl methacrylate doped with 3-(1,1-dicyanoethenyl)-1-phenyl-4,5-dihydro-1H-pyrazole (DCNP)

    NASA Astrophysics Data System (ADS)

    Sznitko, L.; Mysliwiec, J.; Parafiniuk, K.; Szukalski, A.; Palewska, K.; Bartkiewicz, S.; Miniewicz, A.

    2011-08-01

    Luminescence and amplified spontaneous emission (ASE) phenomenon of 3-(1,1-dicyanoethenyl)-1-phenyl-4,5-dihydro-1H-pyrazole (DCNP) dissolved in a polymethyl methacrylate (PMMA) matrix have been studied. We analyzed luminescence from thin films of DCNP-PMMA excited by the neodymium doped yttrium aluminum garnet (Nd:YAG) nanosecond pulsed laser doubled and tripled in frequency. We report on ASE in function of different excitation pulse energy densities (ASE threshold was estimated to be 10 and 13 mJ/cm2 for pumping beams wavelengths of 532 and 355 nm, respectively). We observed the photo-degradation process of a dye and performed exponential gain coefficient measurements (up to 10 cm-1) in the system.

  14. The recombination mechanisms leading to amplified spontaneous emission at the true-green wavelength in CH3NH3PbBr3 perovskites

    NASA Astrophysics Data System (ADS)

    Priante, D.; Dursun, I.; Alias, M. S.; Shi, D.; Melnikov, V. A.; Ng, T. K.; Mohammed, O. F.; Bakr, O. M.; Ooi, B. S.

    2015-02-01

    We investigated the mechanisms of radiative recombination in a CH3NH3PbBr3 hybrid perovskite material using low-temperature, power-dependent (77 K), and temperature-dependent photoluminescence (PL) measurements. Two bound-excitonic radiative transitions related to grain size inhomogeneity were identified. Both transitions led to PL spectra broadening as a result of concurrent blue and red shifts of these excitonic peaks. The red-shifted bound-excitonic peak dominated at high PL excitation led to a true-green wavelength of 553 nm for CH3NH3PbBr3 powders that are encapsulated in polydimethylsiloxane. Amplified spontaneous emission was eventually achieved for an excitation threshold energy of approximately 350 ?J/cm2. Our results provide a platform for potential extension towards a true-green light-emitting device for solid-state lighting and display applications.

  15. SPRAY CHARGING AND TRAPPING SCRUBBER FOR FUGITIVE PARTICLE EMISSION CONTROL

    EPA Science Inventory

    The report gives results of a theoretical and experimental evaluation of the control of fugitive particle emissions (FPE) with a Spray Charging and Trapping (SCAT) Scrubber that uses an air curtain and/or jets to contain, convey, and divert the FPE into a charged spray scrubber. ...

  16. HEALTH AND CLIMATE POLICY IMPACTS ON SULFUR EMISSION CONTROL

    E-print Network

    Russell, Lynn

    . The combination of both climate and health objectives leads to an acceleration of global warming in the 21st warming and health simultaneously will support more stringent fossil fuel and sulfur controls emissions and leading to a reduction in global warming. Citation: Ming, Y., L. M. Russell, and D. F

  17. New Technology Provides Cost-Effective Emissions Control

    E-print Network

    New Technology Provides Cost- Effective Emissions Control Solution for CHP Applications Renewable are the most cost-effective CHP technology less than three MW in size. With a cost effective) applications less than three megawatts (MW). Because they are relatively low cost and have high

  18. Emission control valve with internal spring

    SciTech Connect

    Betterton, J.T.; Glover, A.H.; McKee, T.S.; Romanczuk, C.S.

    1990-03-06

    This patent describe, with an internal combustion engine, a crankcase gas flow control device located between the engine crankcase and the engine fuel-air induction. It comprises: a hollow housing defining an inlet at one end, a cylindrical flow passage, a diverging orifice passage and an outlet passage; a slender rod extending coaxially through the cylindrical flow passage and the diverging orifice passage; a tubular valve element within the housing and supported about the slender rod thereby allowing axial movement of the valve element along the rod; a coil-type compression spring extending about the rod and within the tubular valve element, one end of the spring fixedly connected to the rod, the other end of the spring bearing against the tubular valve element tending to move it along the rod toward the housing inlet and away from the diverging orifice passage whereby a gas pressure differential produced between the crankcase and the fuel-air induction causes the valve element to move against the spring force and resultantly the gas flows over the exterior of the valve element without interference by the spring thereby preventing turbulence. The housing has a walled elbow portion between the diverging orifice passage and the outlet whereby the downstream end of the rod is supported by the elbow wall.

  19. CONTROL OF CENTER-OF-MASS MOTION STATE THROUGH CUING AND DECOUPLING OF SPONTANEOUS GAIT PARAMETERS IN LEVEL WALKING

    PubMed Central

    Espy, D. D.; Yang, F.; Pai, Y.-C.

    2010-01-01

    Can the center of mass (COM) motion state, i.e., its position and velocity relative to the base of support (BOS), which dictate gait stability, be predictably controlled by the global gait parameters of step length and gait speed, or by extension, cadence? The precise relationships among step length and gait speed, and the COM motion state are unknown, partially due to the interdependence between step length and gait speed and the difficulty in independent control of both parameters during spontaneous level walking. The purposes of this study were to utilize simultaneous audio-visual cuing to independently manipulate step length and gait speed, and to determine the extent to which the COM position and velocity can be subsequently controlled. Fifty-six young adults trained at one of three gait patterns in which both the step length and gait speed were targeted simultaneously. The results showed that the cuing could successfully “decouple” gait speed from step length. Although this approach did yield reliable control of the COM velocity through manipulation of gait speed (R2 = 0.97), the manipulation of step length yielded less precise control of COM position (R2 = 0.60). This latter control appears to require manipulation of an additional degree of freedom at the local segment level, such that the inclusion of trunk inclination with step length improved the prediction of COM position (R2 =0.80). PMID:20542513

  20. Control of center of mass motion state through cuing and decoupling of spontaneous gait parameters in level walking.

    PubMed

    Espy, D D; Yang, F; Pai, Y-C

    2010-09-17

    Can the center of mass (COM) motion state, i.e., its position and velocity relative to the base of support (BOS), which dictate gait stability, be predictably controlled by the global gait parameters of step length and gait speed, or by extension, cadence? The precise relationships among step length and gait speed, and the COM motion state are unknown, partially due to the interdependence between step length and gait speed and the difficulty in independent control of both parameters during spontaneous level walking. The purposes of this study were to utilize simultaneous audio-visual cuing to independently manipulate step length and gait speed, and to determine the extent to which the COM position and velocity can be subsequently controlled. Fifty-six young adults were trained at one of the three gait patterns in which both the step length and gait speed were targeted simultaneously. The results showed that the cuing could successfully "decouple" gait speed from step length. Although this approach did yield reliable control of the COM velocity through manipulation of gait speed (R(2)=0.97), the manipulation of step length yielded less precise control of COM position (R(2)=0.60). This latter control appears to require manipulation of an additional degree-of-freedom at the local segment level, such that the inclusion of trunk inclination with step length improved the prediction of COM position (R(2)=0.80). PMID:20542513

  1. Particulate Emissions from a Pre-Emissions Control Era Spark-Ignition Vehicle: A Historical Benchmark

    SciTech Connect

    John M.E. Storey; C. Scott Sluder; Douglas A. Blom; Erin Higinbotham

    2000-06-19

    This study examined the particulate emissions from a pre-emissions control era vehicle operated on both leaded and unleaded fuels for the purpose of establishing a historical benchmark. A pre-control vehicle was located that had been rebuilt with factory original parts to approximate an as-new vehicle prior to 1968. The vehicle had less than 20,000 miles on the rebuilt engine and exhaust. The vehicle underwent repeated FTP-75 tests to determine its regulated emissions, including particulate mass. Additionally, measurements of the particulate size distribution were made, as well as particulate lead concentration. These tests were conducted first with UTG96 certification fuel, followed by UTG96 doped with tetraethyl lead to approximate 1968 levels. Results of these tests, including transmission electron micrographs of individual particles from both the leaded and unleaded case are presented. The FTP composite PM emissions from this vehicle averaged 40.5 mg/mile using unleaded fuel. The results from the leaded fuel tests showed that the FTP composite PM emissions increased to an average of 139.5 mg/mile. Analysis of the particulate size distribution for both cases demonstrated that the mass-based size distribution of particles for this vehicle is heavily skewed towards the nano-particle range. The leaded-fuel tests showed a significant increase in mass concentration at the <0.1 micron size compared with the unleaded-fuel test case. The leaded-fuel tests produced lead emissions of nearly 0.04 g/mi, more than a 4-order-of-magnitude difference compared with unleaded-fuel results. Analysis of the size-fractionated PM samples showed that the lead PM emissions tended to be distributed in the 0.25 micron and smaller size range.

  2. Monolithically integrated resonant-cavity photodetectors for measurement and feedback control of spontaneous and stimulated emission

    Microsoft Academic Search

    James A. Lott

    1997-01-01

    This paper presents a study of the physics and applications of resonant cavity pin photodetectors strategically positioned within the optical structure of vertical microcavity surface emitting devices. Conventional AlGaAs resonant cavity light-emitting diodes and vertical cavity surface emitting lasers (VCSELs) emitting near 780 nm are examined. However, the structures include resonant cavity detectors placed within the upper or lower distributed

  3. Quantum Optical Coherence: Applications in Photon Switching, Control of Spontaneous Emission and Atom Localization 

    E-print Network

    Yang, Shuai

    2013-12-12

    potential structure for atoms and can be used to build atom interferometer [26]. Progresses in experimental techniques also twist atomic, molecular and optical physics with other physics branches. For example, laser cooling combined with the evaporation... cooling techniques enable experimental observation of Bose-Einstein con- densation (BEC) in 1995 [27, 28]. Since then, “atomic physics and quantum optics has met condensed matter physics” [29]. Particularly, the interference of counter- propagating laser...

  4. Air emission control equipment - the new challenge for equpiment suppliers

    SciTech Connect

    Lobb, F.H. [Monsanto Enviro-Chemi, St. Louis, MO (United States)

    1997-12-31

    The combination of Title V, the CAM Rule and the Credible Evidence Rule demand industrial sites view the selection and operation of emission control devices in a whole new light. No longer can users see these devices as detached end of pipe pieces of equipment essentially purchased off lowest bid. These regulatory changes force plants to fully integrate the operation of these devices into their process control systems and instrumentation. And this is specifically EPA`s stated intent. EPA believes that by forcing sites to exercise the same knowledge and attention to air emissions that they do to operate their production processes, emissions will undergo a natural reduction across the country. Process and operational data that historically has been the sole province of sites becomes public. And compliance with state defined requirements must be demonstrated essentially continuously. This paper explores the new approach to compliance and provides insight through specific field examples/installations of emission control equipment. The author seeks to promote understanding through discussion of these significant regulatory changes.

  5. The effects of energy paths and emission controls and standards on future trends in China's emissions of primary air pollutants

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Zhang, J.; Nielsen, C. P.

    2014-03-01

    To examine the efficacy of China's actions to control atmospheric pollution, three levels of growth of energy consumption and three levels of implementation of emission controls are estimated, generating a total of nine combined activity-emission control scenarios that are then used to estimate trends of national emissions of primary air pollutants through 2030. The emission control strategies are expected to have more effects than the energy paths on the future emission trends for all the concerned pollutants. As recently promulgated national action plans of air pollution prevention and control (NAPAPPC) are implemented, China's anthropogenic pollutant emissions should decline. For example, the emissions of SO2, NOx, total primary particulate matter (PM), PM10, and PM2.5 are estimated to decline 7%, 20%, 41%, 34%, and 31% from 2010 to 2030, respectively, in the "best guess" scenario that includes national commitment of energy saving policy and partial implementation of NAPAPPC. Should the issued/proposed emission standards be fully achieved, a less likely scenario, annual emissions would be further reduced, ranging from 17% (for primary PM2.5) to 29% (for NOx) declines in 2015, and the analogue numbers would be 12% and 24% in 2030. The uncertainties of emission projections result mainly from the uncertain operational conditions of swiftly proliferating air pollutant control devices and lack of detailed information about emission control plans by region. The predicted emission trends by sector and chemical species raise concerns about current pollution control strategies: the potential for emissions abatement in key sectors may be declining due to the near saturation of emission control devices use; risks of ecosystem acidification could rise because emissions of alkaline base cations may be declining faster than those of SO2; and radiative forcing could rise because emissions of positive-forcing carbonaceous aerosols may decline more slowly than those of SO2 emissions and thereby concentrations of negative-forcing sulfate particles. Expanded control of emissions of fine particles and carbonaceous aerosols from small industrial and residential sources is recommended, and a more comprehensive emission control strategy targeting a wider range of pollutants and taking account of more diverse environmental impacts is also urgently needed.

  6. The effects of energy paths and emission controls and standards on future trends in China's emissions of primary air pollutants

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Zhang, J.; Nielsen, C. P.

    2014-09-01

    To examine the efficacy of China's actions to control atmospheric pollution, three levels of growth of energy consumption and three levels of implementation of emission controls are estimated, generating a total of nine combined activity-emission control scenarios that are then used to estimate trends of national emissions of primary air pollutants through 2030. The emission control strategies are expected to have more effects than the energy paths on the future emission trends for all the concerned pollutants. As recently promulgated national action plans of air pollution prevention and control (NAPAPPC) are implemented, China's anthropogenic pollutant emissions should decline. For example, the emissions of SO2, NOx, total suspended particles (TSP), PM10, and PM2.5 are estimated to decline 7, 20, 41, 34, and 31% from 2010 to 2030, respectively, in the "best guess" scenario that includes national commitment of energy saving policy and implementation of NAPAPPC. Should the issued/proposed emission standards be fully achieved, a less likely scenario, annual emissions would be further reduced, ranging from 17 (for primary PM2.5) to 29% (for NOx) declines in 2015, and the analogue numbers would be 12 and 24% in 2030. The uncertainties of emission projections result mainly from the uncertain operational conditions of swiftly proliferating air pollutant control devices and lack of detailed information about emission control plans by region. The predicted emission trends by sector and chemical species raise concerns about current pollution control strategies: the potential for emissions abatement in key sectors may be declining due to the near saturation of emission control devices use; risks of ecosystem acidification could rise because emissions of alkaline base cations may be declining faster than those of SO2; and radiative forcing could rise because emissions of positive-forcing carbonaceous aerosols may decline more slowly than those of SO2 emissions and thereby concentrations of negative-forcing sulfate particles. Expanded control of emissions of fine particles and carbonaceous aerosols from small industrial and residential sources is recommended, and a more comprehensive emission control strategy targeting a wider range of pollutants (volatile organic compounds, NH3 and CO, etc.) and taking account of more diverse environmental impacts is also urgently needed.

  7. Spontaneous organisation of ZnS nanoparticles into monocrystalline nanorods with highly enhanced dopant-related emission

    NASA Astrophysics Data System (ADS)

    Manzoor, K.; Aditya, V.; Vadera, S. R.; Kumar, N.; Kutty, T. R. N.

    2005-07-01

    A natural self-assembly process of semiconductor nanoparticles leading to the formation of doped, monocrystalline nanorods with highly enhanced dopant-related luminescence properties is reported. ˜4 nm sized, polycrystalline ZnS nanoparticles of zinc-blende (cubic) structure, doped with Cu+-Al3+ or Mn2+ have been aggregated in the aqueous solution and grown into nanorods of length ˜400 nm and aspect ratio ˜12. Transmission electron microscopic (TEM) images indicate crystal growth mechanisms involving both Ostwald-ripening and particle-to-particle oriented-attachment. Sulphur sulphur catenation is proposed for the covalent-linkage between the attached particles. The nanorods exhibit self-assembly mediated quenching of the lattice defect-related emission accompanied by multifold enhancement in the dopant-related emission. This study demonstrates that the collective behavior of an ensemble of bare nanoparticles, under natural conditions, can lead to the formation of functionalized (doped) nanorods with enhanced luminescence properties.

  8. Control of mercury emissions from coal-fired boilers

    SciTech Connect

    Huang, Hann S.; Livengood, C.D.; Wu, Jiann M.

    1993-06-01

    The Development of Advanced Environmental Control Technology project at Argonne is designed to investigate new concepts leading to advanced control technologies for fossil-energy systems. Within that project, specific research tasks are focused on the development of combined NO{sub x}/SO{sub 2}control technologies, evaluation of waste/byproduct materials from advanced flue-gas-cleanup (FGC) systems, and development of new or improved control measures for the abatement of emissions of hazardous air pollutants (HAPs) from fossil-fuel combustion. The last task, which is the subject of this paper, also includes the evaluation of any possible effects of captured HAP species on waste disposal, as well as the evaluation of HAP measuring techniques and instruments. The HAPs currently under investigation in this task include mercury and arsenic compounds. Only experimental activities concerning mercury control are reported in this paper.

  9. Emissions from premixed charge compression ignition (PCCI) combustion and affect on emission control devices

    SciTech Connect

    Parks, II, James E [ORNL; Kass, Michael D [ORNL] [ORNL; Huff, Shean P [ORNL] [ORNL; Barone, Teresa L [ORNL] [ORNL; Lewis Sr, Samuel Arthur [ORNL] [ORNL; Prikhodko, Vitaly Y [ORNL] [ORNL; Storey, John Morse [ORNL] [ORNL

    2010-01-01

    A light-duty diesel engine has been operated in advanced combustion modes known generally as premixed charge compression ignition (PCCI). The emissions have been characterized for several load and speed combinations. Fewer NO{sub x} and particulate matter (PM) emissions are produced by PCCI, but higher CO and hydrocarbon (HC) emissions result. In addition, the nature of the PM differs from conventional combustion; the PM is smaller and has a much higher soluble organic fraction (SOF) content (68% vs. 30% for conventional combustion). Three catalyst technologies were studied to determine the affects of HECC on catalyst performance; the technologies were a lean NO{sub x} trap (LNT), diesel oxidation catalyst (DOC), and diesel particulate filter (DPF). The LNT benefited greatly from the reduced NO{sub x} emissions associated with PCCI. NO{sub x} capacity requirements are reduced as well as overall tailpipe NO{sub x} levels particularly at low load and temperature conditions where regeneration of the LNT is difficult. The DOC performance requirements for PCCI are more stringent due to the higher CO and HC emissions; however, the DOC was effective at controlling the higher CO and HC emissions at conditions above the light-off temperature. Below light-off, CO and HC emissions are problematic. The study of DPF technology focused on the fuel penalties associated with DPF regeneration or 'desoot' due to the different PM loading rates from PCCI vs. conventional combustion. Less frequent desoot events were required from the lower PM from PCCI and, when used in conjunction with an LNT, the lower PM from less frequent LNT regeneration. The lower desoot frequency leads a {approx}3% fuel penalty for a mixture of PCCI and conventional loads vs. {approx}4% for conventional only combustion.

  10. Venturi/vortex technology for controlling chromium electroplating emissions

    SciTech Connect

    Hay, K.J.; Northrup, J. [Army Construction Engineering Research Labs., Champaign, IL (United States); Heck, S.R. [MSE-HKM, Inc., Butte, MT (United States)

    1997-12-31

    A new technology has been developed to control air emissions from hexavalent chromium electroplating tanks. The venturi/vortex scrubber uses a patented drain assembly to pull plating solution, air with toxic particulates above the solution, and unpopped bubbles of generated gases down with a gravity generated vortex effect. The recirculated plating solution acts as the scrubbing liquid and air agitation is eliminated. Separated gases are passed through a condenser/filter to remove any remaining fumes. The device is almost entirely constructed of CPVC. This device offers several advantages over conventional end-of-pipe systems including significantly lower cost, no wastewater, no extensive ventilation system, and emissions are recycled. The system can be is easily retrofitted to existing tanks, however, a loose fitting tank lid is recommended. A pilot demonstration has been performed at Benet Laboratory, Watervliet, NY (US Army) with a 1,500 gallon chromic acid electroplating tank and 1,500 Amps of applied current. Overall chromium emissions results were 0.00002 mg/Amp-hr, surpassing the stringent California State requirement of 0.006 mg/Amp-hr. Emission prevention by capturing unpopped bubbles is the method in which this system reduces the most emissions. The system met current ambient worker safety standards. Two major improvements are recommended: an increase in gas flow rate through the system and a solution to the system`s sensitivity to the plating solution level.

  11. [Positional control of the distribution of spontaneous sister chromatid exchanges along mouse chromosomes].

    PubMed

    Ladygina, T Iu; Gorlov, I L; Borodin, P M

    1991-08-01

    The use of a new method having combined C-band staining and differential staining of sister chromatids allowed to determine a pattern of distribution of spontaneous sister chromatid exchanges (SCE) along cytologically marked chromosomes 1, 2 and 6 of house mouse. All chromosomes displayed the same pattern of SCE distribution: SCEs are most frequent in the middle part of the chromosome arm and rather rare near the centromere and the telomere. It has been suggested that this pattern of distribution is positional, rather chromatin-specific. The chromosome 1 carrying paracentric inversion with breakpoints in the middle part of the arm and just near the telomere has the same pattern of SCE distribution as normal chromosome 1. Double insertion of homogeneously staining regions in the middle part of the chromosome 1 produces increase in the SCE number per chromosome proportional to the physical length of the insertion. In contrast to meiotic recombination, interference between SCEs is not detected. No evidence for existence of the hot-spots of SCE on the junctions between C-positive and C-negative regions, as well as between G-bands and R-bands, has been produced. PMID:1722185

  12. On the understanding and control of the spontaneous heating of dried tannery wastewater sludge.

    PubMed

    Biasin, A; Della Zassa, M; Zerlottin, M; Refosco, D; Bertani, R; Canu, P

    2014-04-01

    We studied the spontaneous heating of dried sludge produced by treating wastewater mainly originating from tanneries. Heating up to burning has been observed in the presence of air and moisture, starting at ambient temperature. To understand and prevent the process we combined chemical and morphological analyses (ESEM) with thermal activity monitoring in insulated vessels. Selective additions of chemicals, either to amplify or depress the reactivity, have been used to investigate and identify both the chemical mechanism causing the sludge self-heating, and a prevention or a mitigation strategy. FeS additions accelerate the onset of reactivity, while S sustains it over time. On the contrary, Ca(OH)2, Na2CO3, NaHCO3, FeCl2, EDTA, NaClO can limit, up to completely preventing, the exothermic activity. All the experimental evidences show that the reactions supporting the dried sludge self-heating involve the Fe/S/O system. The total suppression of the reactivity requires amounts of additives that are industrially incompatible with waste reduction and economics. The best prevention requires reduction or removal of S and Fe from the dried solid matrix. PMID:24484766

  13. Spontaneous oscillations in a model for active control of microvessel diameters

    PubMed Central

    Arciero, J. C.; Secomb, T. W.

    2012-01-01

    A new theory is presented for the origin of spontaneous oscillations in blood vessel diameters that are observed experimentally in the microcirculation. These oscillations, known as vasomotion, involve time-varying contractions of the vascular smooth muscle in the walls of arterioles. It is shown that such oscillations can arise as a result of interactions between the mechanics of the vessel wall and the dynamics of the active contraction of smooth muscle cells in response to circumferential tension in the wall. A theoretical model is developed in which the diameter and the degree of activation in a vessel are dynamic variables. The model includes effects of wall shear stress and oxygen-dependent metabolic signals on smooth muscle activation and is applied to a single vessel and to simplified network structures. The model equations predict limit cycle oscillations for certain ranges of parameters such as wall shear stress, arterial pressure and oxygen consumption rate. Predicted characteristics of the oscillations, including their sensitivity to arterial pressure, are consistent with experimental observations. PMID:21525236

  14. The next generation of automobile emissions reduction: Innovative control of off-cycle emissions

    SciTech Connect

    Potter, T.F.; Lyons, C.E.

    1995-03-01

    Innovative heat management technologies can reduce emissions from cars by an order of magnitude. Substantial reductions would be realized during cold starts and in evaporative emissions. Such improvements result from a new class of variable-conductance steel vacuum insulations that insulate during one time period and take advantage of beneficial thermal conditions during another. Around a catalytic converter, for example, such control allows heat from one driving cycle to catalyze engine-out emissions occurring at the beginning of the next cycle. As with other more efficient uses of heat in automobiles, reduced complexity and cost are likely compared to supplemental catalyst heating systems. In a similar way, thermal cycling of fuel and the resulting vapor release can be reduced or avoided. Urban air quality could be greatly improved by the wide availability of vehicles using these technologies early in the next century. This paper presents analyses and prototype data supporting the design, operation, and rapid market penetration of internal combustion engine vehicles with significantly lower emissions based on such improved thermal management. Potential implications for fleet emissions are discussed.

  15. Health and climate policy impacts on sulfur emission control

    NASA Astrophysics Data System (ADS)

    Ming, Yi; Russell, Lynn M.; Bradford, David F.

    2005-12-01

    Sulfate aerosol from burning fossil fuels not only has strong cooling effects on the Earth's climate but also imposes substantial costs on human health. To assess the impact of addressing air pollution on climate policy, we incorporate both the climate and health effects of sulfate aerosol into an integrated-assessment model of fossil fuel emission control. Our simulations show that a policy that adjusts fossil fuel and sulfur emissions to address both warming and health simultaneously will support more stringent fossil fuel and sulfur controls. The combination of both climate and health objectives leads to an acceleration of global warming in the 21st century as a result of the short-term climate response to the decreased cooling from the immediate removal of short-lived sulfate aerosol. In the long term (more than 100 years), reducing sulfate aerosol emissions requires that we decrease fossil fuel combustion in general, thereby removing some of the coemitted carbon emissions and leading to a reduction in global warming.

  16. An adaptive controller for the administration of closed-circuit anesthesia during spontaneous and assisted ventilation.

    PubMed

    Sharma, A; Griffith, R L; Roy, R J

    1993-01-01

    Although reduced waste of expensive anesthetic gases is a strong incentive to use closed-circuit anesthesia, manual methods of performing closed-circuit anesthesia are labor intensive and thus not widely used. Automation of closed-circuit anesthesia delivery may reduce the work. A pressure-based adaptive controller was designed and tested on mongrel dogs to evaluate the feasibility of automating closed-circuit anesthesia using an accessory to an existing clinical anesthesia machine and a gas analyzer. The controller was found stable and responsive with good control of oxygen concentration and acceptable control of halothane end-tidal concentration. The response time for oxygen was 5.23 +/- 1.26 minutes, and that for halothane was 2.67 +/- 1.83 minutes. The average peak overshoot for halothane at the start of the experiment was 26.9%. This pressure controller differs from previously published closed-circuit anesthesia controllers that measure gas volume changes within a mechanical ventilator. A pressure-based controller is easily attached to a standard anesthesia machine and is compatible with modes of ventilation other than controlled mechanical ventilation. The controller used in this study is not designed for clinical use, but was developed to investigate the feasibility of pressure as a basis for gas volume control in closed-circuit anesthesia administration. PMID:8463802

  17. 40 CFR 91.113 - Requirement of certification-emission control information label and engine identification number.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...certification-emission control information label and engine identification number. 91.113 Section...EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Standards and Certification...emission control information label and engine identification number. (a)...

  18. 40 CFR 91.113 - Requirement of certification-emission control information label and engine identification number.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...certification-emission control information label and engine identification number. 91.113 Section...EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Standards and Certification...emission control information label and engine identification number. (a)...

  19. 40 CFR 91.113 - Requirement of certification-emission control information label and engine identification number.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...certification-emission control information label and engine identification number. 91.113 Section...EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Standards and Certification...emission control information label and engine identification number. (a)...

  20. 40 CFR 91.113 - Requirement of certification-emission control information label and engine identification number.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...certification-emission control information label and engine identification number. 91.113 Section...EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Standards and Certification...emission control information label and engine identification number. (a)...

  1. 65 FR 62414 - National Emission Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2000-10-18

    ...emission source are due to combustion associated with the use of...an increased frequency of spontaneous abortions and decreased frequency...control information Enclosed Combustion are not a required...Control device means a combustion device, recovery...

  2. Control of NOx emissions by reburning: Summary report

    Microsoft Academic Search

    M. L. Meadows; B. P. Kuo; A. Roberts; S. M. Puski

    1996-01-01

    This report serves as a summary of reburning technologies that are being tested on coal-fired, utility boilers and reflects on-going work in the field of reburning systems. In Chapter 2, the chemistry of NOx formation in coal-fired boilers is presented along with the theoretical basis for NOx emission control through reburning. Also in Chapter 2, an overview various types of

  3. Controlled synthesis and tunable properties of ultrathin silica nanotubes through spontaneous polycondensation on polyamine fibrils.

    PubMed

    Yuan, Jian-Jun; Zhu, Pei-Xin; Noda, Daisuke; Jin, Ren-Hua

    2013-01-01

    This paper describes a facile approach to a biomimetic rapid fabrication of ultrathin silica nanotubes with a highly uniform diameter of 10 nm and inner hollow of around 3 nm. The synthesis is carried out through a spontaneous polycondensation of alkoxysilane on polyamine crystalline fibrils that were conveniently produced from the neutralization of a solution of protonated linear polyethyleneimine (LPEI-H(+)) by alkali compounds. A simple mixing the fibrils with alkoxysilane in aqueous solution allowed for the rapid formation of silica to produce LPEI@silica hybrid nanotubes. These 10-nm nanotubes were hierarchically organized in a mat-like morphology with a typical size of 1-2 micrometers. The subsequent removal of organic LPEI via calcination resulted in silica nanotubes that keep this morphology. The morphology, the structure, the pore properties and the formation mechanism of the silica nanotubes were carefully investigated with scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller measurements (BET), and X-ray diffraction (XRD). Detailed studies demonstrated that the formation of the nanotubes depends on the molar ratio of [OH]/[CH2CH2NH] during the neutralization as well as on the basicity of the alkali compound and on the concentration of the silica source. The synthesis of silica nanotubes established here could be easily applied to a fabrication on the kilogram scale. Silica nanotubes that were obtained from the calcination of hybrid nanotubes of LPEI@silica in an N2 atmosphere showed a distinct photoluminescence centered at 540 nm with a maximum excitation wavelength of 320 nm. Furthermore, LPEI@silica hybrid nanotubes were applied to create silica-carbon composite nanotubes by alternative adsorption of ionic polymers and subsequent carbonization. PMID:24367748

  4. Active Control of Combustor Instability Shown to Help Lower Emissions

    NASA Technical Reports Server (NTRS)

    DeLaat, John C.; Chang, Clarence T.

    2002-01-01

    In a quest to reduce the environmental impact of aerospace propulsion systems, extensive research is being done in the development of lean-burning (low fuel-to-air ratio) combustors that can reduce emissions throughout the mission cycle. However, these lean-burning combustors have an increased susceptibility to thermoacoustic instabilities, or high-pressure oscillations much like sound waves, that can cause severe high-frequency vibrations in the combustor. These pressure waves can fatigue the combustor components and even the downstream turbine blades. This can significantly decrease the safe operating life of the combustor and turbine. Thus, suppression of the thermoacoustic combustor instabilities is an enabling technology for lean, low-emissions combustors. Under the Aerospace Propulsion and Power Base Research and Technology Program, the NASA Glenn Research Center, in partnership with Pratt & Whitney and United Technologies Research Center, is developing technologies for the active control of combustion instabilities. With active combustion control, the fuel is pulsed to put pressure oscillations into the system. This cancels out the pressure oscillations being produced by the instabilities. Thus, the engine can have lower pollutant emissions and long life.The use of active combustion instability control to reduce thermo-acoustic-driven combustor pressure oscillations was demonstrated on a single-nozzle combustor rig at United Technologies. This rig has many of the complexities of a real engine combustor (i.e., an actual fuel nozzle and swirler, dilution cooling, etc.). Control was demonstrated through modeling, developing, and testing a fuel-delivery system able to the 280-Hz instability frequency. The preceding figure shows the capability of this system to provide high-frequency fuel modulations. Because of the high-shear contrarotating airflow in the fuel injector, there was some concern that the fuel pulses would be attenuated to the point where they would not be effective for control. Testing in the combustor rig showed that open-loop pulsing of the fuel was, in fact, able to effectively modulate the combustor pressure. To suppress the combustor pressure oscillations due to thermoacoustic instabilities, it is desirable to time the injection of the fuel so that it interferes with the instability. A closed-loop control scheme was developed that uses combustion pressure feedback and a phase-shifting controller to time the fuel-injection pulses. Some suppression of the pressure oscillations at the 280-Hz instability frequency was demonstrated (see the next figure). However, the overall peak-to- peak pressure oscillations in the combustor were only mildly reduced. Improvements to control hardware and control methods are being continued to gain improved closed-loop reduction of the pressure oscillations.pulse the fuel at

  5. The Impact of Particulate Emissions Control On the Control of Other MWC Air Emissions

    Microsoft Academic Search

    Theodore G. Brna; James D. Kilgroe

    1990-01-01

    On December 20, 1989, the Environmental Protection Agency (EPA) proposed revised new source performance standards for new municipal waste combustion (MWC) units and guidelines for existing sources. The proposed national regulations require tighter particulate matter control and address pre-combustion, combustion, and post-combustion controls, the latter two depending on capacity and age of the facility.The air pollutants of concern when municipal

  6. Technology for CO{sub 2} emission monitoring and control

    SciTech Connect

    Joyce, E.L. Jr.; Unkefer, P.J.; Pendergrass, J.H.; Parkinson, W.J.; Loose, V.W.; Brainard, J.R.

    1998-12-31

    The authors examined three specific areas relative to CO{sub 2} emissions and controls: (1) the effect of deregulation of the utility industry on emissions, (2) the role of advanced power systems in reducing emissions, and (3) developing CO{sub 2} mitigation technologies. In this work the Energy Technologies program office at Los Alamos attempted to initiate an integrated approach that includes a range of tasks involving both point and distributed CO{sub 2} control. The authors have examined evolving mitigation (separation and sequestration) technologies for CO{sub 2} disposal. The separation of hydrogen gas from high-temperature CO{sub 2}-containing streams is a critical component of carbon dioxide mitigation technology, and cost-effective point sequestration will require separation of CO{sub 2} from H{sub 2}. They investigated four types of separation techniques: two high-temperature membrane technologies, an intermediate-temperature membrane technology, and a separation technology based on the formation of CO{sub 2} hydrate compounds through reaction of CO{sub 2} with water at near freezing conditions. At Los Alamos, sequestration technologies are being developed along three principal areas: mineral sequestration of CO{sub 2}, the enhancement of natural sinks using biotechnology methods, and the conversion of CO{sub 2} to methanol using high-temperature photolysis.

  7. Emission control of gas effluents from geothermal power plants.

    PubMed

    Axtmann, R C

    1975-01-01

    Geothermal steam at the world's five largest power plants contains from 0.15 to 30% noncondensable gases including CO(2), H(2)S, H(2), CH(4), N(2), H(3)BO(3), and NH(3). At four of the plants the gases are first separated from the steam and then discharged to the environment; at the fifth, the noncondensables exhaust directly to the atmosphere along with spent steam. Some CO(2) and sulfur emission rates rival those from fossil-fueled plants on a per megawatt-day basis. The ammonia and boron effluents can interfere with animal and plant life. The effects of sulfur (which emerges as H(2)S but may oxidize to SO(2)) on either ambient air quality or longterm human health are largely unknown. Most geothermal turbines are equipped with direct contact condensers which complicate emission control because they provide two or more pathways for the effluents to reach the environment. Use of direct contact condensers could permit efficient emission control if coupled to processes that produce saleable quantities of purified carbon dioxide and elemental sulfur. PMID:1132388

  8. Emission control of four-stroke motorcycle engine

    SciTech Connect

    Wu, C.Y.Y.; Peng, Y.Y.; Gau, T.H.

    1995-12-31

    Experimental studies of the intake-generated charge motion (swirl and tumble) and engine combustion were conducted in a 125 cc four-stroke motorcycle engine. In this work, a Variable Inlet Port (VIP) was designed to generate various levels of charge motion in different operation conditions. The static flow test and the engine experiments were performed to study the effects of inlet charge motion on the engine combustion, cycle variation, fuel consumption and exhaust emissions. The results show that the cycle variation decreased, the lean limit extended, and the burning rate and the fuel economy increased when the charge motion increased. With this new design of flow control system, the motorcycle can be run with lean mixture and drastically reduce the exhaust emissions and fuel consumption while still maintaining high specific power output.

  9. Control of breathing during cortical substitution of the spontaneous automatic respiratory rhythm

    Microsoft Academic Search

    Philippe Haouzi; Bruno Chenuel; Brian J. Whipp

    2007-01-01

    This study addresses the following question: does the ventilatory control system adjust total ventilation in accord with the regulatory demands of the physiological dead space ventilation (V?D) when the breathing frequency changes, and if so, how? A simple proportionality between the amplitude of the respiratory motor output (VT) and the respiratory period (TTOT) during such changes will not provide for

  10. Failing to Forget: Prospective Memory Commission Errors Can Result from Spontaneous Retrieval and Impaired Executive Control

    ERIC Educational Resources Information Center

    Scullin, Michael K.; Bugg, Julie M.

    2013-01-01

    Prospective memory (PM) research typically examines the ability to remember to execute delayed intentions but often ignores the ability to forget finished intentions. We had participants perform (or not perform; control group) a PM task and then instructed them that the PM task was finished. We later (re)presented the PM cue. Approximately 25% of…

  11. An adaptive controller for the administration of closed-circuit anesthesia during spontaneous and assisted ventilation

    Microsoft Academic Search

    Ashutosh Sharma; Richard L. Griffith; Rob J. Roy

    1993-01-01

    Although reduced waste of expensive anesthetic gases is a strong incentive to use closed-circuit anesthesia, manual methods\\u000a of performing closed-circuit anesthesia are labor intensive and thus not widely used. Automation of closed-circuit anesthesia\\u000a delivery may reduce the work. A pressure-basedadaptive controller was designed and tested on mongrel dogs to evaluate the feasibility of automating closed-circuit anesthesia using an accessory\\u000a to

  12. Spontaneous acute poisoning by Crotalaria retusa in sheep and biological control of this plant with sheep.

    PubMed

    Riet-Correa, F; Carvalho, K S; Dantas, A F M; Medeiros, R M T

    2011-11-01

    After the diagnosis of acute Crotalaria retusa poisoning, 21 healthy sheep from the affected flock were returned to the paddock and continued to consume the sprouting plants. Two years after returning these sheep to the paddock, very few plants were still alive, and after 3 years, no C. retusa plants were observed. The sheep had neither clinical signs nor biochemical alterations and delivered healthy lambs. It is concluded that resistant sheep can be used for the biological control of C. retusa. PMID:21930140

  13. 40 CFR 65.145 - Nonflare control devices used to control emissions from storage vessels or low-throughput...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Nonflare control devices used to control emissions from storage vessels or low-throughput...CONSOLIDATED FEDERAL AIR RULE Closed Vent Systems, Control Devices, and Routing to a Fuel Gas System or...

  14. Hyperthermia treatment of spontaneously occurring oral cavity tumors using a computer-controlled Nd:YAG laser system

    NASA Astrophysics Data System (ADS)

    Panjehpour, Masoud; Overholt, Bergein F.; Frazier, Donita L.; Klebanow, Edward R.

    1991-05-01

    Conventional hyperthermia treatment of superficial tumors in the oral cavity is difficult due to inability in accessing the lesion. A new hyperthermia technique employing near infrared Nd:YAG irradiation delivered through an optical fiber is introduced for heating oral and nasal tumors in animals. This system consisted of an Nd:YAG laser, a He-Ne laser, a computer controlled optical shutter, an interstitial thermometer, computer and a printer. The tumors were heated via surface illumination of the lesion. A thermocouple implanted in the base of the tumor provided temperature feedback for laser energy regulation. Three spontaneously occurring canine (two squamous cell carcinoma on the gum, one pigmented melanoma on the hard palate) and one feline tumor (squamous cell carcinoma on the nose) have been treated with the Nd:YAG laser-induced hyperthermia delivered following radiation therapy. The tumor temperature was maintained between 43.2-43.5 degree(s)C for one hour. Nd:YAG hyperthermia allowed efficient delivery of heat to veterinary oral and nasal lesions otherwise impossible to treat with conventional heating techniques.

  15. A new method to thermally manage an electronic control unit while reducing radiated emissions

    Microsoft Academic Search

    Imad Sharaa; Daniel N. Aloi

    2008-01-01

    This paper provides a methodology to thermally manage an electronic control unit while reducing its radiated emissions. Measurements of the radiated emission levels for a particular electronic control unit revealed excessive levels. Electronic control units utilize pulse width modulated signals to control an external load. The rise and fall times of the pulse width modulated signal impact both the radiated

  16. Controlling GT arc length from arc light emissions

    SciTech Connect

    Richardson, R.W.; Edwards, F.S. [Ohio State Univ., Columbus, OH (United States)

    1996-12-31

    Conventional systems for mechanized Gas Tungsten Arc (GTA) welding control arc length by utilizing its well known relationship with arc voltage. Such systems maintain a constant arc voltage by movement of the torch relative to the work surface. This has proven to be practicable over the years where the welding machine operator can make frequent visual observations of arc length, and then adjust the arc voltage set point in order to compensate for subtle changes in the arc length/arc voltage relationship. Fully automated robotic type welding systems do not present this luxury since weld cycles are required to proceed over long periods without manual intervention. The key fundamental difficulty is that the arc voltage is dominated by large voltage drops near the electrode surfaces which are independent of arc length. This paper presents a review of past and related work in the area, followed by results of a new study of arc light sensitivity and its application to arc length control. For this work, a standard automatic voltage controller was used which was modified to receive either arc voltage or a suitably scaled voltage signal derived from an arc light emission sensor. This allowed a direct comparison of conventional and arc light based control approaches. It was found that arc light control behaved more robustly when encountering disturbances which are known to seriously trouble a voltage based control. A prime example is welding from one base material onto another which was found to produce only a minor effect on a light based control, but unacceptable behavior of a voltage control. Details of experiments and results are presented.

  17. Influence of motion parallax in the control of spontaneous body sway.

    PubMed

    Guerraz, M; Sakellari, V; Burchill, P; Bronstein, A M

    2000-03-01

    Visual control of postural sway during quiet standing was investigated in normal subjects to see if motion parallax cues were able to improve postural stability. In experiment 1, six normal subjects fixated a fluorescent foreground target, either alone or in the presence of full room illumination. The results showed that subjects reduced body sway when the background was visible. This effect, however, could be mediated not only by parallax cues but also by an increase in the total area of visual field involved. In experiment 2, other parameters such as image angular size and target distance were controlled for. Twelve subjects fixated a two light-emitting diode (LED) target placed at 45 cm from their eyes in a dark room. A second similar two-LED target was placed either at 170 cm (maximum parallax) or at 85 cm (medium parallax) from the fixated target, or in the same plane of the fixated target (0 cm, no parallax). It was found that the amplitude of sway was reduced significantly, by approximately 20%, when the two targets were presented in depth (parallax present) as compared to when they were in the same plane (no parallax). The effect was only present in the lateral direction and for low frequency components of sway (up to 0.5 Hz). We confirmed in experiment 3 on eight subjects with a design similar to that used in experiment 2 that the effect of motion parallax on body sway was of monocular origin since observed with monocular and binocular vision. Geometrical considerations based on these results support the existence of two modes of visual detection of body sway, afferent (retinal slippage) and efferent (extra-retinal or eye-movement based). PMID:10766276

  18. Assessment of the applicability of automotive emission control technology to stationary engines. Final report. [Report

    Microsoft Academic Search

    W. U. Roessler; A. Muraszew; R. D. Kopa

    1974-01-01

    The emission characteristics of uncontrolled stationary diesel, spark ignition, and gas turbine engines are reviewed, and the applicability of automotive emission control technology to stationary engines are analyzed. Nitrogen oxides are the principal pollutant species emitted from these engines. Other pollutants include hydrocarbons, carbon monoxide, smoke, particulates, sulfur oxides, aldehydes, odor, and noise. The emission control techniques developed for these

  19. Odor and air emissions control using biotechnology for both collection and wastewater treatment systems

    Microsoft Academic Search

    Chris Easter; Chris Quigley; Peter Burrowes; Jay Witherspoon; Dirk Apgar

    2005-01-01

    Air emission controls using biotechnology is a new focus area for publicly owned treatment works (POTWs), especially now with many Federal, State, and Local air quality laws and regulations that often require significant air emission reductions for a new plant or collection system source to be permitted. CH2M HILL and others have collected biotechnology-based odor and air emissions control performance

  20. Light-Duty Vehicle Exhaust Emission Control Cost Estimates Using a Part-Pricing Approach

    Microsoft Academic Search

    Quanlu Wang; Catherine Kling; Daniel Sperling

    1993-01-01

    The substantial reductions in motor vehicle emissions that have occurred since the late 1960s have been accompanied by continuous increases in vehicle emission control costs, and cost increases or decreases due to changes in vehicle performance such as driveability, power, fuel economy, and vehicle maintenance. In this paper, a systematic approach has been developed to estimate emission control costs for

  1. Survey of Emissions Associated with Enclosed Combustor Emission Control Devices in the Denver-Julesburg Basin

    NASA Astrophysics Data System (ADS)

    Knighton, W. B.; Floerchinger, C. R.; Wormhoult, J.; Massoli, P.; Fortner, E.; Brooks, B.; Roscioli, J. R.; Bon, D.; Herndon, S. C.

    2014-12-01

    Volatile organic compounds (VOCs) play an important role in local and regional air quality. A large source of VOCs comes from the oil and gas industry and the Denver-Julesburg Basin (D-J Basin) has seen a sharp increase in production in recent years primarily due to advances in horizontal drilling techniques. To help curb emissions with extraction and production of natural gas and its associated oil, emission control devices are required for facilities emitting over 6 tons of hydrocarbons per year. Within the ozone non-attainment area, which encompasses Denver and much of the front range, enclosed combustion devices (enclosed flares) are required to reduce hydrocarbon emissions by at least 95%. While certification tests indicate that these enclosed combustor devices provide high destruction removal efficiencies, there is considerable interest in knowing how well they perform in the field. As part of Front Range Air Pollution and Photochemistry Experiment (FRAPPE) project conducted during the Summer of 2014, the Aerodyne Mobile Laboratory (AML) surveyed oil and gas operations within the Wattenberg gas field and the surrounding D-J Basin. The AML deployed a full suite of gas and particle phase instrumentation providing a comprehensive set of on-line, real-time measurements for the major natural gas components (methane and ethane) and their combustion products (CO2, CO, NOx) using a variety of spectroscopic techniques. Additional gas phase organic gas emissions were made using a proton transfer reaction mass spectrometer (PTR-MS). Particle number and composition were determined using a condensation particle counter and an Aerodyne Aerosol Mass Spectrometer (AMS). A summary of the number of enclosed combustor devices measured and their observed combustion efficiencies will be presented.

  2. Study of emission control strategies for Pennsylvania: Emission reduction from mobile sources, cost effectiveness, and economic impacts. Final report

    Microsoft Academic Search

    K. Goulias; T. Litzinger; J. Nelson; V. Chalamgari

    1993-01-01

    Regional air quality modeling studies conducted by the Ozone Transport Commission indicate that implementing only the mandatory emission control measures of the 1990 Clean Air Act Amendments (CAAA) will not be sufficient to allow the Ozone Transport Region (OTR) to achieve and maintain ozone standards. In this study, a comprehensive emission inventory analysis and a regional economic simulation have provided

  3. N2O and NO2 Emissions from Heavy-Duty Diesel Trucks with Advanced Emission Controls

    NASA Astrophysics Data System (ADS)

    Preble, C.; Harley, R.; Kirchstetter, T.

    2014-12-01

    Diesel engines are the largest source of nitrogen oxides (NOx) emissions nationally, and also a major contributor to the black carbon (BC) fraction of fine particulate matter (PM). Recently, diesel particle filter (DPF) and selective catalytic reduction (SCR) emission control systems that target exhaust PM and NOx have become standard equipment on new heavy-duty diesel trucks. However, the deliberate catalytic oxidation of engine-out nitric oxide (NO) to nitrogen dioxide (NO2) in continuously regenerating DPFs leads to increased tailpipe emission of NO2. This is of potential concern due to the toxicity of NO2 and the resulting increases in atmospheric formation of other air pollutants such as ozone, nitric acid, and fine PM. While use of SCR reduces emissions of both NO and NO2, it may lead to increased emissions of nitrous oxide (N2O), a potent greenhouse gas. Here we report results from on-road measurements of heavy-duty diesel truck emissions conducted at the Port of Oakland and the Caldecott Tunnel in the San Francisco Bay Area. Emission factors (g pollutant per kg of diesel) were linked via recorded license plates to individual truck attributes, including engine model year and installed emission control equipment. Between 2009 and 2013, the fraction of DPF-equipped trucks at the Port of Oakland increased from 2 to 99%, and median engine age decreased from 11 to 6 years. Over the same period, fleet-average emission factors for black carbon and NOx decreased by 76 ± 22% and 53 ± 8%, respectively. However, direct emissions of NO2 increased, and consequently the NO2/NOx emission ratio increased from 0.03 ± 0.02 to 0.18 ± 0.03. Older trucks retrofitted with DPFs emitted approximately 3.5 times more NO2 than newer trucks equipped with both DPF and SCR. Preliminary data from summer 2014 measurements at the Caldecott Tunnel suggest that some older trucks have negative emission factors for N2O, and that for newer trucks, N2O emission factors have changed sign and are significantly increased. More comprehensive analysis of the effects of SCR on diesel NOx and N2O emissions will be reported in the presentation. These on-road emission studies indicate that advanced emission control systems such as DPF and SCR dramatically reduce PM and NOx emissions, but can cause undesirable side effects like increased NO2 and N2O emissions.

  4. Southern California Edison's (SCE) Research Program for Industrial Volatile Organic Compound (VOC) Emissions Control 

    E-print Network

    Sung, R. D.; Cascone, R.; Reese, J.

    1990-01-01

    SCE has developed and implemented a research program for customer retention through VOC emission control. Following characterization of problematic emission sources, SCE has identified and evaluated a number of alternative solutions and is currently...

  5. Spontaneous pneumothorax

    PubMed Central

    2011-01-01

    Introduction The incidence of spontaneous pneumothorax is 24/100,000 a year in men and 9.9/100,000 a year in women in England and Wales. The major contributing factor is smoking, which increases the likelihood by 22 times in men, and by 8 times in women. While death from spontaneous pneumothorax is rare, rates of recurrence are high, with one study of men in the USA finding a total recurrence rate of 35%. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments in people presenting with spontaneous pneumothorax? What are the effects of interventions to prevent recurrence in people with previous spontaneous pneumothorax? We searched: Medline, Embase, The Cochrane Library, and other important databases up to January 2010 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 17 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: chest-tube drainage (alone or plus suction), chest tubes (small, standard sizes, one-way valves), needle aspiration, and pleurodesis. PMID:21477390

  6. Implementing Strategies for Drying and Pressing Wood Without Emissions Controls

    SciTech Connect

    Sujit Banerjee; Terrance Conners

    2007-09-07

    Drying and pressing wood for the manufacture of lumber, particleboard, oriented strand board (OSB), veneer and medium density fiberboard (MDF) release volatile organic compounds (VOCs) into the atmosphere. These emissions require control equipment that are capital-intensive and consume significant quantities of natural gas and electricity. The objective of our work was to understand the mechanisms through which volatile organic compounds are generated and released and to develop simple control strategies. Of the several strategies developed, two have been implemented for OSB manufacture over the course of this study. First, it was found that increasing final wood moisture by about 2-4 percentage points reduced the dryer emissions of hazardous air pollutants by over 70%. As wood dries, the escaping water evaporatively cools the wood. This cooling tapers off wood when the wood is nearly dry and the wood temperature rises. Thermal breakdown of the wood tissue occurs and VOCs are released. Raising the final wood moisture by only a few percentage points minimizes the temperature rise and reduces emissions. Evaporative cooling also impacts has implications for VOC release from wood fines. Flaking wood for OSB manufacture inevitable generates fines. Fines dry out rapidly because of their high surface area and evaporative cooling is lost more rapidly than for flakes. As a result, fines emit a disproportionate quantity of VOCs. Fines can be reduced in two ways: through screening of the green furnish and through reducing their generation during flaking. The second approach is preferable because it also increased wood yield. A procedure to do this by matching the sharpness angle of the flaker knife to the ambient temperature was also developed. Other findings of practical interests are as follows: Dielectric heating of wood under low-headspace conditions removes terpenes and other extractives from softwood; The monoterpene content in trees depend upon temperature and seasonal effects; Method 25A emissions from lumber drying can be modeled from a knowledge of the airflow through the kiln; A heat transfer model shows that VOCs released during hot-pressing mainly originate from the surface of the board; and Boiler ash can be used to adsorb formaldehyde from air streams.

  7. Quality control of positron emission tomography radiopharmaceuticals: An institutional experience

    PubMed Central

    Shukla, Jaya; Vatsa, Rakhee; Garg, Nitasha; Bhusari, Priya; Watts, Ankit; Mittal, Bhagwant R

    2013-01-01

    Purpose of the Study: To study quality control parameters of routinely prepared positron emission tomography (PET) radiopharmaceuticals. Materials and Methods: Three PET radiopharmaceuticals fluorine-18 fluorodeoxyglucose (F-18 FDG), N-13 ammonia (N-13 NH3), and Ga-68 DOTATATE (n = 25 each), prepared by standardized protocols were used. The radionuclide purity, radiochemical purity, residual solvents, pH, endotoxins, and sterility of these radiopharmaceuticals were determined. Results: The physical half-life of radionuclide in radiopharmaceuticals, determined by both graphical and formula method, demonstrated purity of radionuclides used. pH of all PET radiopharmaceuticals used was in the range of 5-6.5. No microbial growth was observed in radiopharmaceutical preparations. The residual solvents, chemical impurity, and pyrogens were within the permissible limits. Conclusions: All three PET radiopharmaceuticals were safe for intravenous administration. PMID:24379528

  8. Controlling satellite communication system unwanted emissions in congested RF spectrum

    NASA Astrophysics Data System (ADS)

    Olsen, Donald; Heymann, Roger

    2007-09-01

    The International Telecommunication Union (ITU), a United Nations (UN) agency, is the agency that, under an international treaty, sets radio spectrum usage regulations among member nations. Within the United States of America (USA), the organization that sets regulations, coordinates an application for use, and provides authorization for federal government/agency use of the radio frequency (RF) spectrum is the National Telecommunications and Information Administration (NTIA). In this regard, the NTIA defines which RF spectrum is available for federal government use in the USA, and how it is to be used. The NTIA is a component of the United States (U.S.) Department of Commerce of the federal government. The significance of ITU regulations is that ITU approval is required for U.S. federal government/agency permission to use the RF spectrum outside of U.S. boundaries. All member nations have signed a treaty to do so. U.S. federal regulations for federal use of the RF spectrum are found in the Manual of Regulations and Procedures for Federal Radio Frequency Management, and extracts of the manual are found in what is known as the Table of Frequency Allocations. Nonfederal government and private sector use of the RF spectrum within the U.S. is regulated by the Federal Communications Commission (FCC). There is a need to control "unwanted emissions" (defined to include out-of-band emissions, which are those immediately adjacent to the necessary and allocated bandwidth, plus spurious emissions) to preclude interference to all other authorized users. This paper discusses the causes, effects, and mitigation of unwanted RF emissions to systems in adjacent spectra. Digital modulations are widely used in today's satellite communications. Commercial communications sector standards are covered for the most part worldwide by Digital Video Broadcast - Satellite (DVB-S) and digital satellite news gathering (DSNG) evolutions and the second generation of DVB-S (DVB-S2) standard, developed by the European Telecommunications Standards Institute (ETSI). In the USA, the Advanced Television Systems Committee (ATSC) has adopted Europe's DVB-S and DVB-S2 standards for satellite digital transmission. With today's digital modulations, RF spectral side lobes can extend out many times the modulating frequency on either side of the carrier at excessive power levels unless filtered. Higher-order digital modulations include quadrature phase shift keying (QPSK), 8 PSK (8-ary phase shift keying), 16 APSK (also called 12-4 APSK (amplitude phase shift keying)), and 16 QAM (quadrature amplitude modulation); they are key for higher spectrum efficiency to enable higher data rate transmissions in limited available bandwidths. Nonlinear high-power amplifiers (HPAs) can regenerate frequency spectral side lobes on input-filtered digital modulations. The paper discusses technologies and techniques for controlling these spectral side lobes, such as the use of square root raised cosine (SRRC) filtering before or during the modulation process, HPA output power back-off (OPBO), and RF filters after the HPA. Spectral mask specifications are a common method of the NTIA and ITU to define spectral occupancy power limits. They are intended to reduce interference among RF spectrum users by limiting excessive radiation at frequencies beyond the regulatory allocated bandwidth.The focus here is on the communication systems of U.S. government satellites used for space research, space operations, Earth exploration satellite services (EESS), meteorological satellite services (METSATS), and other government services. The 8025 to 8400 megahertz (MHz) X band can be used to illustrate the "unwanted emissions" issue. 8025 to 8400 MHz abuts the 8400 to 8450 MHz band allocated by the NTIA and ITU to space research for space-to-Earth transmissions such as receiving very weak Deep Space Network signals. The views and ideas expressed in this paper are those of the authors and do not necessarily reflect those of The Aerospace Corporation or The National Oceanic and Atmosphe

  9. A bi-hemispheric neuronal network model of the cerebellum with spontaneous climbing fiber firing produces asymmetrical motor learning during robot control

    PubMed Central

    Pinzon-Morales, Ruben-Dario; Hirata, Yutaka

    2014-01-01

    To acquire and maintain precise movement controls over a lifespan, changes in the physical and physiological characteristics of muscles must be compensated for adaptively. The cerebellum plays a crucial role in such adaptation. Changes in muscle characteristics are not always symmetrical. For example, it is unlikely that muscles that bend and straighten a joint will change to the same degree. Thus, different (i.e., asymmetrical) adaptation is required for bending and straightening motions. To date, little is known about the role of the cerebellum in asymmetrical adaptation. Here, we investigate the cerebellar mechanisms required for asymmetrical adaptation using a bi-hemispheric cerebellar neuronal network model (biCNN). The bi-hemispheric structure is inspired by the observation that lesioning one hemisphere reduces motor performance asymmetrically. The biCNN model was constructed to run in real-time and used to control an unstable two-wheeled balancing robot. The load of the robot and its environment were modified to create asymmetrical perturbations. Plasticity at parallel fiber-Purkinje cell synapses in the biCNN model was driven by error signal in the climbing fiber (cf) input. This cf input was configured to increase and decrease its firing rate from its spontaneous firing rate (approximately 1 Hz) with sensory errors in the preferred and non-preferred direction of each hemisphere, as demonstrated in the monkey cerebellum. Our results showed that asymmetrical conditions were successfully handled by the biCNN model, in contrast to a single hemisphere model or a classical non-adaptive proportional and derivative controller. Further, the spontaneous activity of the cf, while relatively small, was critical for balancing the contribution of each cerebellar hemisphere to the overall motor command sent to the robot. Eliminating the spontaneous activity compromised the asymmetrical learning capabilities of the biCNN model. Thus, we conclude that a bi-hemispheric structure and adequate spontaneous activity of cf inputs are critical for cerebellar asymmetrical motor learning. PMID:25414644

  10. Spontaneous emission of a two-level static atom coupling with the electromagnetic vacuum fluctuations outside a high-dimensional Einstein Gauss-Bonnet black hole

    E-print Network

    Ming Zhang; Zhan-Ying Yang; Rui-Hong Yue

    2014-07-04

    In present paper, by using the generalized DDC formalism, we investigate the spontaneous excitation of an static atom interacting with electromagnetic vacuum fluctuations outside a EGB black hole in $d$-dimensions. We find that spontaneous excitation does not occur in Boulware vacuum. The Gauss-Bonnet term has no effect on the stability of the atom. Finally, we discuss the contribution of the coupling constant and dimensional factor to the results in three different kinds of spacetime.

  11. The next decade and emission controls for electric utilities

    SciTech Connect

    Herrin, W.D. [Southern Company Services, Birmingham, AL (United States)

    1997-12-31

    The historical efforts to achieve attainment with the ozone and particulate related standards span over 25 years and involve billions of dollars with only minimal success related to ozone and unknown success related to certain fine particulates. The 1990 Clean Air Act Amendments mandated significant new efforts, including Title IV - Acid Rain, to achieve reductions in ozone and fine particulate precursors and attainment with the standards. Initial reduction efforts have only recently been implemented and yet another hot summer continues to portray our futile efforts to gain much ground towards attainment with existing and revised or new standards. In order to review the issues more fully and to investigate the issue of regional transport. EPA has given the states a reprieve on ozone attainment plans until mid-1997 and set up the Clean Air Act Advisory Committee (CAAAC) structure to review implementation issues with new or revised standards. The states and other stockholders are involved in these EPA processes through the Ozone Transport Assessment Group (OTAG) and the CAAAC along with numerous working groups to get new answers arid help towards innovative solutions. A major target in these efforts is emissions from fossil-fuel fired utility boilers. The OTAG process has developed regional control strategy targets for utility NO{sub x} sources at three levels. These levels include consideration of costs, timing and availability of controls, and the anticipated reductions in NO{sub x}. The CAAAC is also considering regional controls and the associated implementation issues for both ozone and fine particulates. EPA is also considering a Clean Air Power Initiative (CAPI) to wrap all the utility control issues in a single consensus package. The next 10 years will be a crucial time for electric utilities in juggling environmental and competitive issues.

  12. Simulation of mercury emission control by activated carbon under confined-bed operations

    Microsoft Academic Search

    T. C. Ho; S. Shetty; H. W. Chu; C. J. Lin; J. R. Hopper

    2008-01-01

    Mercury emissions from coal-fired power plants have been a great environmental and regulatory concern due to the toxic nature of mercury and the significant amount of emissions from these plants. An effective method for controlling mercury emission is to employ activated carbon to adsorb mercury from the combustion flue gas. In this study, an activated carbon mercury sorption model was

  13. The observed response of the Aura OMI NO2 column to NOx emission controls on

    E-print Network

    Jacob, Daniel J.

    . The AQS surface sites only detect "nose-level" concentrations. #12;Regulations of NOx Emissions EmissionThe observed response of the Aura OMI NO2 column to NOx emission controls on power plants : 2005 (~68% decrease since late 1990s) 1998 NOx State Implementation Plan (SIP) Call 22 eastern states

  14. Spontaneous and stimulated emission in the mid-ultraviolet range of quantum-well heterostructures based on AlGaN compounds grown by molecular beam epitaxy on c-sapphire substrates

    NASA Astrophysics Data System (ADS)

    Lutsenko, E. V.; Rzheutskii, N. V.; Pavlovskii, V. N.; Yablonskii, G. P.; Nechaev, D. V.; Sitnikova, A. A.; Ratnikov, V. V.; Kuznetsova, Ya. V.; Zhmerik, V. N.; Ivanov, S. V.

    2013-10-01

    This paper reports on the results of investigations of the spontaneous and stimulated luminescence in AlGaN heterostructures with a single quantum well and a high Al content (up to ˜80 mol % in barrier layers), which were grown by plasma assisted molecular beam epitaxy (PAMBE) on c-sapphire substrates. It has been demonstrated that the stimulated emission occurs in the mid-ultraviolet range of the spectrum at wavelengths of 259, 270, and 289 nm with threshold excitation power densities of 1500, 900, and 700 kW/cm2, respectively. It has been shown that there exists a possibility of TE polarization ( E ? c) of both stimulated and spontaneous luminescence down to wavelengths of 259 nm.

  15. Mercury Emission Control Technologies for PPL Montana-Colstrip Testing

    SciTech Connect

    John P. Kay; Michael L. Jones; Steven A. Benson

    2007-04-01

    The Energy & Environmental Research Center (EERC) was asked by PPL Montana LLC (PPL) to provide assistance and develop an approach to identify cost-effective options for mercury control at its coal-fired power plants. The work conducted focused on baseline mercury level and speciation measurement, short-term parametric testing, and week long testing of mercury control technology at Colstrip Unit 3. Three techniques and various combinations of these techniques were identified as viable options for mercury control. The options included oxidizing agents or sorbent enhancement additives (SEAs) such as chlorine-based SEA1 and an EERC proprietary SEA2 with and without activated carbon injection. Baseline mercury emissions from Colstrip Unit 3 are comparatively low relative to other Powder River Basin (PRB) coal-fired systems and were found to range from 5 to 6.5 g/Nm3 (2.9 to 3.8 lb/TBtu), with a rough value of approximately 80% being elemental upstream of the scrubber and higher than 95% being elemental at the outlet. Levels in the stack were also greater than 95% elemental. Baseline mercury removal across the scrubber is fairly variable but generally tends to be about 5% to 10%. Parametric results of carbon injection alone yielded minimal reduction in Hg emissions. SEA1 injection resulted in 20% additional reduction over baseline with the maximum rate of 400 ppm (3 gal/min). Week long testing was conducted with the combination of SEA2 and carbon, with injection rates of 75 ppm (10.3 lb/hr) and 1.5 lb/MMacf (40 lb/hr), respectively. Reduction was found to be an additional 30% and, overall during the testing period, was measured to be 38% across the scrubber. The novel additive injection method, known as novel SEA2, is several orders of magnitude safer and less expensive than current SEA2 injection methods. However, used in conjunction with this plant configuration, the technology did not demonstrate a significant level of mercury reduction. Near-future use of this technique at Colstrip is not seen. All the additives injected resulted in some reduction in mercury emissions. However, the target reduction of 55% was not achieved. The primary reason for the lower removal rates is because of the lower levels of mercury in the flue gas stream and the lower capture level of fine particles by the scrubbers (relative to that for larger particles). The reaction and interaction of the SEA materials is with the finer fraction of the fly ash, because the SEA materials are vaporized during the combustion or reaction process and condense on the surfaces of entrained particles or form very small particles. Mercury will have a tendency to react and interact with the finer fraction of entrained ash and sorbent as a result of the higher surface areas of the finer particles. The ability to capture the finer fraction of fly ash is the key to controlling mercury. Cost estimates for mercury removal based on the performance of each sorbent during this project are projected to be extremely high. When viewed on a dollar-per-pound-of-mercury removed basis activated carbon was projected to cost nearly $1.2 million per pound of mercury removed. This value is roughly six times the cost of other sorbent-enhancing agents, which were projected to be closer to $200,000 per pound of mercury removed.

  16. COST EFFECTIVE VOC EMISSION CONTROL STARTEGIES FOR MILITARY, AEROSPACE,AND INDUSTRIAL PAINT SPRAY BOOTH OPERATIONS: COMBINING IMPROVED VENTILATION SYSTEMS WITH INNOVATIVE, LOW COST EMISSION CONTROL TECHNOLOGIES

    EPA Science Inventory

    The paper describes a full-scale demonstration program in which several paint booths were modified for recirculation ventilation; the booth exhaust streams are vented to an innovative volatile organic compound (VOC) emission control system having extremely low operating costs. ...

  17. Randomized controlled trial of probiotics for the prevention of spontaneous preterm delivery associated with intrauterine infection: study protocol

    Microsoft Academic Search

    Leticia Krauss-Silva; Maria Elizabeth L Moreira; Mariane B Alves; Maria R Rezende; Alcione Braga; Karla G Camacho; Maria Rosa R Batista; Clarisse Savastano; Antonio Almada-Horta; Fernando Guerra

    2010-01-01

    BACKGROUND: Spontaneous preterm deliveries that occur before the 34th week of gestation, and particularly before the 32nd week of gestation, have been strongly associated to intrauterine infection, ascending from vagina, and represent the largest portion of neonatal deaths and neurological problems. Bacterial vaginosis, characterized by a diminished or absent flora of lactobacilli and increased colonization of several anaerobic or facultative

  18. How light, temperature, and measurement and growth [CO2] interactively control isoprene emission in hybrid aspen.

    PubMed

    Niinemets, Ülo; Sun, Zhihong

    2015-02-01

    Plant isoprene emissions have been modelled assuming independent controls by light, temperature and atmospheric [CO2]. However, the isoprene emission rate is ultimately controlled by the pool size of its immediate substrate, dimethylallyl diphosphate (DMADP), and isoprene synthase activity, implying that the environmental controls might interact. In addition, acclimation to growth [CO2] can shift the share of the control by DMADP pool size and isoprene synthase activity, and thereby alter the environmental sensitivity. Environmental controls of isoprene emission were studied in hybrid aspen (Populus tremula × Populus tremuloides) saplings acclimated either to ambient [CO2] of 380 ?mol mol(-1) or elevated [CO2] of 780 ?mol mol(-1). The data demonstrated strong interactive effects of environmental drivers and growth [CO2] on isoprene emissions. Light enhancement of isoprene emission was the greatest at intermediate temperatures and was greater in elevated-[CO2]-grown plants, indicating greater enhancement of the DMADP supply. The optimum temperature for isoprene emission was higher at lower light, suggesting activation of alternative DMADP sinks at higher light. In addition, [CO2] inhibition of isoprene emission was lost at a higher temperature with particularly strong effects in elevated-[CO2]-grown plants. Nevertheless, DMADP pool size was still predicted to more strongly control isoprene emission at higher temperatures in elevated-[CO2]-grown plants. We argue that interactive environmental controls and acclimation to growth [CO2] should be incorporated in future isoprene emission models at the level of DMADP pool size. PMID:25399006

  19. How light, temperature, and measurement and growth [CO2] interactively control isoprene emission in hybrid aspen

    PubMed Central

    Niinemets, Ülo; Sun, Zhihong

    2015-01-01

    Plant isoprene emissions have been modelled assuming independent controls by light, temperature and atmospheric [CO2]. However, the isoprene emission rate is ultimately controlled by the pool size of its immediate substrate, dimethylallyl diphosphate (DMADP), and isoprene synthase activity, implying that the environmental controls might interact. In addition, acclimation to growth [CO2] can shift the share of the control by DMADP pool size and isoprene synthase activity, and thereby alter the environmental sensitivity. Environmental controls of isoprene emission were studied in hybrid aspen (Populus tremula × Populus tremuloides) saplings acclimated either to ambient [CO2] of 380 ?mol mol–1 or elevated [CO2] of 780 ?mol mol–1. The data demonstrated strong interactive effects of environmental drivers and growth [CO2] on isoprene emissions. Light enhancement of isoprene emission was the greatest at intermediate temperatures and was greater in elevated-[CO2]-grown plants, indicating greater enhancement of the DMADP supply. The optimum temperature for isoprene emission was higher at lower light, suggesting activation of alternative DMADP sinks at higher light. In addition, [CO2] inhibition of isoprene emission was lost at a higher temperature with particularly strong effects in elevated-[CO2]-grown plants. Nevertheless, DMADP pool size was still predicted to more strongly control isoprene emission at higher temperatures in elevated-[CO2]-grown plants. We argue that interactive environmental controls and acclimation to growth [CO2] should be incorporated in future isoprene emission models at the level of DMADP pool size. PMID:25399006

  20. EVALUATION OF NOX EMISSION CONTROL CATALYSTS FOR POWER PLANT SCR INSTALLATIONS

    EPA Science Inventory

    The paper gives results of an evaluation of nitrogen oxide (NOx) emission control catalysts commercially developed for power plant selective catalytic reduction (SCR) installations. ith the objective of establishing the performance of SCR catalysts and related technology, control...

  1. MULTIPOLLUTANT EMISSION CONTROL TECHNOLOGY OPTIONS FOR COAL-FIRED POWER PLANTS

    EPA Science Inventory

    The report presents and analyzes various existing and novel control technologies designed to achieve multipollutant [sulfur dioxide (SO2), nitrogen oxide (NOX), and mercury (Hg)] emission reductions. Summary descriptions are included of 23 multipollutant control technologies that...

  2. The Effect of Pleural Abrasion on the Treatment of Primary Spontaneous Pneumothorax: A Systematic Review of Randomized Controlled Trials

    PubMed Central

    Ming, Mo-yu; Cai, Shuang-qi; Chen, Yi-Qiang

    2015-01-01

    Background Pleural abrasion has been widely used to control the recurrence of primary spontaneous pneumothorax (PSP). However, controversy still exists regarding the advantages and disadvantages of pleural abrasion compared with other interventions in preventing the recurrence of PSP. Methods The PubMed, Embase, and Cochrane Central Register of Controlled Trials databases were searched up to December 15, 2014 to identify randomized controlled trials (RCTs) that compared the effects of pleural abrasion with those of other interventions in the treatment of PSP. The study outcomes included the PSP recurrence rate and the occurrence rate of adverse effects. Results Mechanical pleural abrasion and apical pleurectomy after thoracoscopic stapled bullectomy exhibited similarly persistent postoperative air leak occurrence rates (p = 0.978) and 1-year PSP recurrence rates (p = 0.821), whereas pleural abrasion led to reduced residual chest pain and discomfort (p = 0.001) and a smaller rate of hemothorax (p = 0.036) than did apical pleurectomy. However, the addition of minocycline pleurodesis to pleural abrasion did not reduce the pneumothorax recurrence rate compared with apical pleurectomy (3.8% for both procedures) but was associated with fewer complications. There was no statistical difference in the pneumothorax recurrence rate between mechanical pleural abrasion and chemical pleurodesis with minocycline on either an intention-to-treat basis (4 of 42 versus 0 of 42, p = 0.12; Fisher exact test) or after exclusions (2 of 40 versus 0 of 42, p = 0.24; Fisher exact test). Pleural abrasion plus minocycline pleurodesis also did not reduce the pneumothorax recurrence rate compared with pleural abrasion alone (p = 0.055). Moreover, pleural abrasion plus minocycline pleurodesis was associated with more intense acute chest pain. The postoperative overall recurrence rate in patients who underwent staple line coverage with absorbable cellulose mesh and fibrin glue was similar to that with mechanical abrasion after thoracoscopic bullectomy (13.8% vs. 14.2%, respectively; p = 0.555), but staple line coverage resulted in less postoperative residual pain than mechanical abrasion (0.4% vs.3.2%; p<0.0001). Pleural abrasion after thoracoscopic wedge resection did not decrease the recurrence of pneumothorax compared with wedge resection alone (p = 0.791), but the intraoperative bleeding and postoperative pleural drainage rates were higher when pleural abrasion was performed. Conclusions In addition to resulting in the same pneumothorax recurrence rate, thoracoscopic pleural abrasion with or without minocycline pleurodesis is safer than apical pleurectomy in the treatment of PSP. However, minocycline pleurodesis with or without pleural abrasion is not any more effective than pleural abrasion alone. Moreover, additional mechanical abrasion is not safer than additional staple line coverage with absorbable cellulose mesh and fibrin glue after thoracoscopic bullectomy because of increased postoperative pain. Additionally, pleural abrasion after thoracoscopic wedge resection should not be recommended for routine application due to the greater incidence of adverse effects than wedge resection alone. However, further large-scale, well-designed RCTs are needed to confirm the best procedure. PMID:26042737

  3. 40 CFR 75.34 - Units with add-on emission controls.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false Units with add-on emission controls. 75.34 Section...Substitution Procedures § 75.34 Units with add-on emission controls. (a) The owner or operator of an affected unit equipped with add-on SO2 and/or NOX...

  4. HEV Control Strategy for Real-Time Optimization of Fuel Economy and Emissions

    Microsoft Academic Search

    Valerie H. Johnson; Keith B. Wipke; David J. Rausen

    2000-01-01

    Hybrid electric vehicles (HEV's) offer additional flexibility to enhance the fuel economy and emissions of vehicles. The Real-Time Control Strategy (RTCS) presented here optimizes efficiency and emissions of a parallel configuration HEV. In order to determine the ideal operating point of the vehicle's engine and motor, the control strategy considers all possible engine-motor torque pairs. For a given operating point,

  5. 40 CFR 63.1316 - PET and polystyrene affected sources-emissions control provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 false PET and polystyrene affected sources-emissions control...Polymers and Resins § 63.1316 PET and polystyrene affected sources—emissions control...operator of an affected source producing polystyrene using a continuous process...

  6. Engine Performance (Section C: Emission Control Systems). Auto Mechanics Curriculum Guide. Module 3. Instructor's Guide.

    ERIC Educational Resources Information Center

    Rains, Larry

    This engine performance (emission control systems) module is one of a series of competency-based modules in the Missouri Auto Mechanics Curriculum Guide. Topics of this module's five units are: positive crankcase ventilation (PCV) and evaporative emission control systems; exhaust gas recirculation (EGR); air injection and catalytic converters;…

  7. Preface: Special Issue on Catalytic Control of Lean-Burn Engine Exhaust Emissions

    SciTech Connect

    Yezerets, Aleksey; Peden, Charles HF; Szanyi, Janos; Nova, Isabella; Epling, Bill

    2012-04-30

    This issue of Catalysis Today includes original research articles based on select presentations from the Mobile Emissions Control Symposium at the 22nd North American Catalysis Society (NACS) Meeting held in Detroit in June 2011, with a particular focus on catalyzed diesel emissions control. The Symposium was dedicated to the memory of Dr. Haren Gandhi, a visionary technology leader and a passionate environmental advocate.

  8. ASSESSMENT OF ROAD CARPET FOR CONTROL OF FUGITIVE EMISSIONS FROM UNPAVED ROADS

    EPA Science Inventory

    The report gives results of an assessment of the use of carpeting to control fugitive emissions from unpaved roads. Historically, emissions from unpaved roads have been controlled by watering, oiling, or chemical soil stabilization. An analysis of the forces which produce emissio...

  9. MULTIPOLLUTANT EMISSION CONTROL TECHNOLOGY OPTIONS FOR COAL-FIRED POWER PLANTS

    EPA Science Inventory

    The report presents and analyzes various existing and novel control technologies designed to achieve multi-emission [sulfur dioxide (SO2), nitrogen oxide (NOX), and mercury (Hg)] reductions. Summary descriptions are included of 27 multi-emission control technologies that have rea...

  10. STRUCTURAL TRANSFORMATIONS IN CA-BASED SORBENTS USED FOR SO2 EMISSION CONTROL

    EPA Science Inventory

    The paper discusses structural transformations in Ca-based sorbents used for SO2 emission control. conomizer temperature injection of Ca-based sorbents is an option for dry control of SO2 emissions from coal-fired boilers. heir reactivity with SO2 was found to be a function of th...

  11. Marine omega-3 polyunsaturated fatty acids induce sex-specific changes in reinforcer-controlled behaviour and neurotransmitter metabolism in a spontaneously hypertensive rat model of ADHD

    PubMed Central

    2012-01-01

    Background Previous reports suggest that omega-3 (n-3) polyunsaturated fatty acids (PUFA) supplements may reduce ADHD-like behaviour. Our aim was to investigate potential effects of n-3 PUFA supplementation in an animal model of ADHD. Methods We used spontaneously hypertensive rats (SHR). SHR dams were given n-3 PUFA (EPA and DHA)-enriched feed (n-6/n-3 of 1:2.7) during pregnancy, with their offspring continuing on this diet until sacrificed. The SHR controls and Wistar Kyoto (WKY) control rats were given control-feed (n-6/n-3 of 7:1). During postnatal days (PND) 25–50, offspring were tested for reinforcement-dependent attention, impulsivity and hyperactivity as well as spontaneous locomotion. The animals were then sacrificed at PND 55–60 and their neostriata were analysed for monoamine and amino acid neurotransmitters with high performance liquid chromatography. Results n-3 PUFA supplementation significantly enhanced reinforcement-controlled attention and reduced lever-directed hyperactivity and impulsiveness in SHR males whereas the opposite or no effects were observed in females. Analysis of neostriata from the same animals showed significantly enhanced dopamine and serotonin turnover ratios in the male SHRs, whereas female SHRs showed no change, except for an intermediate increase in serotonin catabolism. In contrast, both male and female SHRs showed n-3 PUFA-induced reduction in non-reinforced spontaneous locomotion, and sex-independent changes in glycine levels and glutamate turnover. Conclusions Feeding n-3 PUFAs to the ADHD model rats induced sex-specific changes in reinforcement-motivated behaviour and a sex-independent change in non-reinforcement-associated behaviour, which correlated with changes in presynaptic striatal monoamine and amino acid signalling, respectively. Thus, dietary n-3 PUFAs may partly ameliorate ADHD-like behaviour by reinforcement-induced mechanisms in males and partly via reinforcement-insensitive mechanisms in both sexes. PMID:23228189

  12. Energy, Carbon-emission and Financial Savings from Thermostat Control

    SciTech Connect

    Blasing, T J [ORNL; Schroeder, Dana [University of Georgia, Athens, GA

    2013-08-01

    Among the easiest approaches to energy, and cost, savings for most people is the adjustment of thermostats to save energy. Here we estimate savings of energy, carbon, and money in the United States of America (USA) that would result from adjusting thermostats in residential and commercial buildings by about half a degree Celsius downward during the heating season and upward during the cooling season. To obtain as small a unit as possible, and therefore the least likely to be noticeable by most people, we selected an adjustment of one degree Fahrenheit (0.56 degree Celsius) which is the gradation used almost exclusively on thermostats in the USA and is the smallest unit of temperature that has been used historically. Heating and/or cooling of interior building space for personal comfort is sometimes referred to as space conditioning, a term we will use for convenience throughout this work without consideration of humidity. Thermostat adjustment, as we use the term here, applies to thermostats that control the indoor temperature, and not to other thermostats such as those on water heaters. We track emissions of carbon only, rather than of carbon dioxide, because carbon atoms change atomic partners as they move through the carbon cycle, from atmosphere to biosphere or ocean and, on longer time scales, through the rock cycle. To convert a mass of carbon to an equivalent mass of carbon dioxide (thereby including the mass of the 2 oxygen atoms in each molecule) simply multiply by 3.67.

  13. FUEL FORMULATION EFFECTS ON DIESEL FUEL INJECTION, COMBUSTION, EMISSIONS AND EMISSION CONTROL

    SciTech Connect

    Boehman, A; Alam, M; Song, J; Acharya, R; Szybist, J; Zello, V; Miller, K

    2003-08-24

    This paper describes work under a U.S. DOE sponsored Ultra Clean Fuels project entitled ''Ultra Clean Fuels from Natural Gas,'' Cooperative Agreement No. DE-FC26-01NT41098. In this study we have examined the incremental benefits of moving from low sulfur diesel fuel and ultra low sulfur diesel fuel to an ultra clean fuel, Fischer-Tropsch diesel fuel produced from natural gas. Blending with biodiesel, B100, was also considered. The impact of fuel formulation on fuel injection timing, bulk modulus of compressibility, in-cylinder combustion processes, gaseous and particulate emissions, DPF regeneration temperature and urea-SCR NOx control has been examined. The primary test engine is a 5.9L Cummins ISB, which has been instrumented for in-cylinder combustion analysis and in-cylinder visualization with an engine videoscope. A single-cylinder engine has also been used to examine in detail the impacts of fuel formulation on injection timing in a pump-line-nozzle fueling system, to assist in the interpretation of results from the ISB engine.

  14. Control technology for radioactive emissions to the atmosphere at US Department of Energy facilities

    SciTech Connect

    Moore, E.B.

    1984-10-01

    The purpose of this report is to provide information to the US Environmental Protection agency (EPA) on existing technology for the control of radionuclide emissions into the air from US Department of Energy (DOE) facilities, and to provide EPA with information on possible additional control technologies that could be used to further reduce these emissions. Included in this report are generic discussions of emission control technologies for particulates, iodine, rare gases, and tritium. Also included are specific discussions of existing emission control technologies at 25 DOE facilities. Potential additional emission control technologies are discussed for 14 of these facilities. The facilities discussed were selected by EPA on the basis of preliminary radiation pathway analyses. 170 references, 131 figures, 104 tables.

  15. Control of NOx Emissions from Stationary Combustion Sources

    EPA Science Inventory

    In general, NOx control technologies are categorized as being either primary control technologies or secondary control technologies. Primary control technologies reduce the formation of NOx in the primary combustion zone. In contrast, secondary control technologies destroy the NO...

  16. Response of spontaneously hypertensive rats to inhalation of fine and ultrafine particles from traffic: experimental controlled study

    Microsoft Academic Search

    Ingeborg M Kooter; A John F Boere; Paul Hb Fokkens; Daan Lac Leseman; Jan Ama Dormans; Flemming R Cassee

    2007-01-01

    ABSTRACT\\\\BACKGROUND:Many epidemiological studies have shown that mass concentrations of ambient particulate matter (PM) are associated with adverse health effects in the human population. Since PM is still a very crude measure, this experimental study has explored the role of two distinct size fractions: ultrafine (<0.15 mum) and fine (0.15- 2.5 mum) PM. In a series of 2-day inhalation studies, spontaneously

  17. Quantifying the effects of China's pollution control on atmospheric mercury emissions

    NASA Astrophysics Data System (ADS)

    Zhong, H.

    2014-12-01

    China has conducted series of air pollution control policies to reduce the pollutant emissions. Although not specifically for mercury (Hg), those policies are believed to have co-benefits on atmospheric Hg emission control. On the basis of field-tests data and updated information of energy conservation and emission control, we have developed multiple-year inventories of anthropogenic mercury emissions in China from 2005 to 2012. Three scenarios (scenario 0(S0), scenario 1(S1), scenario 2(S2)) with different emission controls and energy path are designed for prediction of the future Hg emissions for the country. In particular, comprehensive assessments has been conducted to evaluate the evolution of emission factors, recent emission trends, effects of control measures as well as the reliability of our results. The national total emissions of anthropogenic Hg are estimated to increase from 679.0 metric tons (t) in 2005 to 749.8 t in 2012, with the peak at 770.6 t in 2011. The annual growth rate of emissions can then be calculated at 2.1% during 2005-2011, much lower than that of energy consumption or economy of the country. Coal combustion, gold metallurgy and nonferrous metal smelting are the most significant Hg sources of anthropogenic origin, accounting together for 85% of national total emissions. Tightened air pollution controls in China should be important reasons for the smooth emission trends. Compared with 2005, 299 t Hg were reduced in 2010 from power plants, iron and steel smelting, nonferrous-smelting and cement production, benefiting from the improvement of control measures for those sectors. The speciation of Hg emissions is relatively stable for recent years, with the mass fractions of around 55%, 9% and 6% for Hg0, Hg2+ and Hgp respectively. Integrating the policy commitments on energy saving, different from the most conservative case S0, S2 shares the same energy path with S1, but includes more stringent emission control. Under those scenarios, we predict China's atmospheric Hg emissions are 814, 805, and 620 t for 2015, 844, 823, and 621t for 2020, and 869, 813t, and 579t for 2030. Compared to levels of energy consumption and industrial production, policies on emission control would have greater benefits for Hg abatement for the country.

  18. Risk factors and surgical outcomes for spontaneous rupture of BCLC stages A and B hepatocellular carcinoma: A case-control study

    PubMed Central

    Li, Jing; Huang, Liang; Liu, Cai-Feng; Cao, Jie; Yan, Jian-Jun; Xu, Feng; Wu, Meng-Chao; Yan, Yi-Qun

    2014-01-01

    AIM: To investigate the risk factors and surgical outcomes for spontaneous rupture of Barcelona Clinic Liver Cancer (BCLC) stages A and B hepatocellular carcinoma (HCC). METHODS: From April 2002 to November 2006, 92 consecutive patients with spontaneous rupture of BCLC stage A or B HCC undergoing hepatic resection were included in a case group. A control arm of 184 cases (1:2 ratio) was chosen by matching the age, sex, BCLC stage and time of admission among the 2904 consecutive patients with non-ruptured HCC undergoing hepatic resection. Histological confirmation of HCC was available for all patients and ruptured HCC was confirmed by focal discontinuity of the tumor with surrounding perihepatic hematoma observed intraoperatively. Patients with microvascular thrombus in the hepatic vein branches were excluded from the study. Clinical data and survival time were collected and analysed. RESULTS: Sixteen patients were excluded from the study based on exclusion criteria, of whom 3 were in the case group and 13 in the control group. Compared with the control group, more patients in the case group had underlying diseases of hypertension (10.1% vs 3.5%, P = 0.030) and liver cirrhosis (82.0% vs 57.9%, P < 0.001). Tumors in 67 (75.3%) patients in the case group were located in segments II, III and VI, and the figure in the control group was also 67 (39.7%) (P < 0.001). On multivariate analysis, hypertension (HR = 7.38, 95%CI: 1.91-28.58, P = 0.004), liver cirrhosis (HR = 6.04, 95%CI: 2.83-12.88, P < 0.001) and tumor location in segments II, III and VI (HR = 5.03, 95%CI: 2.70-6.37, P < 0.001) were predictive for spontaneous rupture of HCC. In the case group, the median survival time and median disease-free survival time were 12 mo (range: 1-78 mo) and 4 mo (range: 0-78 mo), respectively. The 1-, 3- and 5-year overall survival rates and disease-free survival rates were 66.3%, 23.4% and 10.1%, and 57.0%, 16.8% and 4.5%, respectively. Only radical resection remained predictive for overall survival (HR = 0.32, 95%CI: 0.08-0.61, P = 0.015) and disease-free survival (HR = 0.12, 95%CI: 0.01-0.73, P = 0.002). CONCLUSION: Tumor location, hypertension and liver cirrhosis are associated with spontaneous rupture of HCC. One-stage hepatectomy should be recommended to patients with BCLC stages A and B disease. PMID:25083085

  19. FIELD TESTING OF EMISSION CONTROLS FOR ASBESTOS MANUFACTURING WASTE PILES

    EPA Science Inventory

    Abatement of fugitive emissions from asbestos cement waste disposal activities has been studied. The primary sources of asbestos emissions are, (1) transfer of baghouse fines to the dump, (2) crushing and leveling of waste on the fines, (3) active dump areas, (4) inactive dump ar...

  20. COMBUSTION CONTROL OF ORGANIC EMISSIONS FROM MUNICIPAL WASTE COMBUSTORS

    EPA Science Inventory

    More than two decades ago, researchers identified benzo(a)pyrene and other organic species in the emissions from incineration of solid waste. Chlorinated dibenzo-p-dioxins and-furans (CDD/CDF) were first detected in municipal waste combustor (MWC) emissions in 1977. Since then, C...

  1. CHARACTERIZATION OF EMISSIONS FROM COMBUSTION SOURCES: CONTROLLED STUDIES

    EPA Science Inventory

    The paper summarizes Session I papers (given at the EPA Workshop on Characterization of Contaminant Emissions from Indoor Sources, Chapel Hill, NC, May 1985) that illustrate the progress made to date on characterizing indoor combustion emissions from unvented space heaters, gas a...

  2. ORGANIC EMISSIONS FROM FERROUS METALLURGICAL INDUSTRIES: COMPILATION OF EMISSION FACTORS AND CONTROL TECHNOLOGIES

    EPA Science Inventory

    The report gives results of a review and analysis of the information and data available in the public domain on organic emissions from the ferrous metallurgy industry, specifically the iron and steel, iron foundry, and ferroalloy industries. Emission sources and information gaps ...

  3. Delay-feedback control strategy for reducing CO2 emission of traffic flow system

    NASA Astrophysics Data System (ADS)

    Zhang, Li-Dong; Zhu, Wen-Xing

    2015-06-01

    To study the signal control strategy for reducing traffic emission theoretically, we first presented a kind of discrete traffic flow model with relative speed term based on traditional coupled map car-following model. In the model, the relative speed difference between two successive running cars is incorporated into following vehicle's acceleration running equation. Then we analyzed its stability condition with discrete control system stability theory. Third, we designed a delay-feedback controller to suppress traffic jam and decrease traffic emission based on modern controller theory. Last, numerical simulations are made to support our theoretical results, including the comparison of models' stability analysis, the influence of model type and signal control on CO2 emissions. The results show that the temporal behavior of our model is superior to other models, and the traffic signal controller has good effect on traffic jam suppression and traffic CO2 emission, which fully supports the theoretical conclusions.

  4. Fast pulsed operation of a small non-radioactive electron source with continuous emission current control

    NASA Astrophysics Data System (ADS)

    Cochems, P.; Kirk, A. T.; Bunert, E.; Runge, M.; Goncalves, P.; Zimmermann, S.

    2015-06-01

    Non-radioactive electron sources are of great interest in any application requiring the emission of electrons at atmospheric pressure, as they offer better control over emission parameters than radioactive electron sources and are not subject to legal restrictions. Recently, we published a simple electron source consisting only of a vacuum housing, a filament, and a single control grid. In this paper, we present improved control electronics that utilize this control grid in order to focus and defocus the electron beam, thus pulsing the electron emission at atmospheric pressure. This allows short emission pulses and excellent stability of the emitted electron current due to continuous control, both during pulsed and continuous operations. As an application example, this electron source is coupled to an ion mobility spectrometer. Here, the pulsed electron source allows experiments on gas phase ion chemistry (e.g., ion generation and recombination kinetics) and can even remove the need for a traditional ion shutter.

  5. 40 CFR 266.104 - Standards to control organic emissions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...the trial burn (for new facilities or an interim status facility applying for a permit) or compliance test (for interim status facilities), determine emission rates...the “Hazardous Waste Combustion Air Quality Screening...

  6. 40 CFR 266.104 - Standards to control organic emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...the trial burn (for new facilities or an interim status facility applying for a permit) or compliance test (for interim status facilities), determine emission rates...the “Hazardous Waste Combustion Air Quality Screening...

  7. 40 CFR 266.104 - Standards to control organic emissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...the trial burn (for new facilities or an interim status facility applying for a permit) or compliance test (for interim status facilities), determine emission rates...the “Hazardous Waste Combustion Air Quality Screening...

  8. 40 CFR 266.104 - Standards to control organic emissions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...the trial burn (for new facilities or an interim status facility applying for a permit) or compliance test (for interim status facilities), determine emission rates...the “Hazardous Waste Combustion Air Quality Screening...

  9. 40 CFR 266.104 - Standards to control organic emissions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...the trial burn (for new facilities or an interim status facility applying for a permit) or compliance test (for interim status facilities), determine emission rates...the “Hazardous Waste Combustion Air Quality Screening...

  10. Environmental factors controlling methane emissions from peatlands in northern Minnesota

    NASA Technical Reports Server (NTRS)

    Dise, Nancy B.; Gorham, Eville; Verry, Elon S.

    1993-01-01

    The environmental factors affecting the emission of methane from peatlands were investigated by correlating CH4 emission data for two years, obtained from five different peatland ecosystems in northern Minnesota, with peat temperature, water table position, and degree of peat humification. The relationship obtained between the CH4 flux and these factors was compared to results from a field manipulation experiment in which the water table was artificially raised in three experimental plots within the driest peatland. It was found that peat temperature, water table position, and degree of peat humification explained 91 percent of the variance in log CH4 flux, successfully predicted annual CH4 emission from individual wetlands, and predicted the change in flux due to the water table manipulation. Raising the water table in the bog corrals by an average of 6 cm in autumn 1989 and 10 cm in summer 1990 increased CH4 emission by 2.5 and 2.2 times, respectively.

  11. CONTROL OF EMISSIONS FROM RESIDENTIAL WOOD BURNING BY COMBUSTION MODIFICATION

    EPA Science Inventory

    The report describes an exploratory study of factors contributing to atmospheric emissions from residential wood-fired combustion equipment. Three commercial appliances were operated with both normal and modified designs, providing different burning modes: updraft with a grate, u...

  12. CONTROL TECHNOLOGIES FOR FUGITIVE VOC EMISSIONS FROM CHEMICAL PROCESSES

    EPA Science Inventory

    This handbook contains information concerning volatile organic compound (VOC) emissions from the synthetic organic chemicals manufacturing industry (SOCMI), petroleum refineries, on-shore natural gas processing plants, polymer manufacturing plants, benzene from particular equipme...

  13. Evidence for solar wind control of Saturn radio emission

    NASA Technical Reports Server (NTRS)

    Desch, M. D.

    1982-01-01

    Using data collected by the Voyager 1 and 2 spacecraft in 1980 and 1981, strong evidence is presented for a direct correlation between variations in the solar wind at Saturn and the level of activity of Saturn's nonthermal radio emission. Correlation coefficients of 57 to 58% are reached at lag times of 0 to 1 days between the arrival at Saturn of high pressure solar wind streams and the onset of increased radio emission. The radio emission exhibits a long-term periodicity of 25 days, identical to the periodicity seen in the solar wind at this time and consistent with the solar rotation period. The energy coupling efficiency between the solar wind with the Saturn radio emission is estimated and compared with that for Earth.

  14. A randomised controlled trial of probiotics for the prevention of spontaneous preterm delivery associated with bacterial vaginosis: preliminary results

    PubMed Central

    2011-01-01

    Background Bacterial vaginosis increases the risk of spontaneous preterm delivery at less than 34 weeks of gestation. Objective The purpose of this study was to evaluate the efficacy of the early administration of selected lactobacilli strains (probiotics) to pregnant women with asymptomatic bacterial vaginosis/intermediate-degree infections to prevent spontaneous premature delivery and associated neonatal morbidity. Methods/Design Asymptomatic pregnant women at less than 20 weeks of gestation, with no indication of elective preterm delivery, with a vaginal pH ? 4.5 and Nugent score > 3 were randomly assigned to the placebo or intervention group (oral administration of selected lactobacilli up to the 24th to 26th week of gestation). The randomisation was stratified for the history of premature delivery (HPD) and blocked. The allocation was concealed, and the participating health professionals and patients were blinded. The primary outcome was preterm delivery (<34 to <32 weeks), and the secondary outcomes were associated neonatal complications. Results In total, 4,204 pregnant women were screened; 320 and 324 individuals were respectively randomly assigned to the placebo and intervention groups, and 62% finished the trial. None of the randomised patients were lost to follow-up. For the non-HPD stratum, the intent-to-treat relative risks of spontaneous premature birth at < 34 and < 37 weeks' gestation were 0.33 (0.03, 3.16) and 0.49 (0.17, 1.44), respectively, and they were non-significant (ns) with p = 0.31 and 0.14. The corresponding actual treatment figures were zero and 0.32 (0.09, 1.19), which were ns with p = 0.12 and 0.06. The intent-to-treat relative risk of spontaneous premature birth at < 37 weeks of gestation for the trial as a whole, including HPD and non-HPD participants, was 0.69 (0.26, 1.78), p = 0.30 (ns). The neonatal complications under evaluation occurred in only one infant (< 34 weeks; placebo group) who presented with respiratory distress syndrome and suspected early neonatal sepsis. The recorded adverse events were minor and relatively non-specific. Conclusions The efficacy of the tested probiotics to prevent preterm delivery among women without a history of preterm delivery was not determined because the study sample was insufficient to estimate statistically significant intent-to-treat effects; additional studies are needed to evaluate this intervention among these women. Trial registration Trial registration at NIH register: NCT00303082. Sources of funding: the Brazilian Health Ministry and the State of Rio de Janeiro Research Foundation. PMID:22059409

  15. Fossil-fuel carbon emission control in irrigated maize production

    Microsoft Academic Search

    B. D. Wind; W. W. Wallender

    1997-01-01

    To evaluate optimal management strategies which reduce fossil-fuel carbon emissions, an idealized gross returns objective function was developed for the production of irrigated maize with the inclusion of a disincetive carbon-taxing term. The gross returns objective function is multivariant and optimized through a gradient search procedure. Carbon emissions emanating from maize production stem from the utilization of fossil-fuel energy on

  16. Emissions and demonstration of an emission control technology for small two-stroke utility engines.

    PubMed

    Welch, William; Durbin, Thomas D

    2004-02-01

    Small utility engines represent an important contribution to the emissions inventory and have been subjected to increasingly stringent regulations in recent years. For this project, a Tanaka two-stroke engine was tested in its original condition and with a modified fuel/oil injection system. The modified fuel/oil injection system applied to the Tanaka two-stroke engine resulted in significant emissions reductions of approximately 52% for carbon monoxide (CO), 70% for total hydrocarbons (THC), 70% for particulate matter (PM), and 67% for the regulated THC + nitrogen oxides metric. This technology met the California Air Resources Board's 2000 model-year regulations for all pollutants, with the exception of slightly higher PM emissions. Two additional two-stroke engines were tested under a new condition and after at least 100 hr of use to examine the effects of deterioration on in-use, two-stroke engines. For one engine, CO and PM emissions more than tripled after 162 hr of operation in the field, with smaller increases also observed for THC (20%). For the second engine, significant repairs were required throughout the 100 operating hours, which counteracted the effects of the emissions deterioration and resulted in lower CO and THC emissions. PMID:14977321

  17. The Spontaneously Hypertensive Rat as a Model of Human Cardiovascular Disease: Evidence of Exacerbated Cardiopulmonary Injury and Oxidative Stress from Inhaled Emission Particulate Matter

    Microsoft Academic Search

    Urmila P. Kodavanti; Mette C. Schladweiler; Allen D. Ledbetter; William P. Watkinson; Matthew J. Campen; Darrell W. Winsett; Judy R. Richards; Kay M. Crissman; Gary E. Hatch; Daniel L. Costa

    2000-01-01

    Cardiovascular disease is considered a probable risk factor of particulate matter (PM)-related mortality and morbidity. It was hypothesized that rats with hereditary systemic hypertension and underlying cardiac disease would be more susceptible than healthy normotensive rats to pulmonary injury from inhaled residual oil fly ash (ROFA) PM. Eight spontaneously hypertensive (SH) and eight normotensive Wistar–Kyoto (WKY) rats (12–13 weeks old)

  18. [Spontaneous pneumomediastinum].

    PubMed

    Legrand, M; Dassonneville, J C; Lesobre, R

    Spontaneous pneumomediastinum is a relatively rare disease, the clinical signs of which may be misleading, and the physiopathology is still unknown. The authors report 7 cases collected over a period of 3 years and note the etiology, the clinical findings and the X-ray findings. The disease often affectsyoung sybjects, without any sex predominance. The initial symptom is thoracic pain and is often accompanied by dispnea. Subcutaneous emphysema only appears secondarily and may be mild. The association with pneumothorax is not rare. Among the etiological circumstances, pneumomediastinum often occurs after an effort or a respiratory infection with dyspnea. The diagnosis depends on the discovery of subcutaneous emphysema and on radiological signs in A.P. and lateral chest views. Treatment should be as conservative as possible in the usual benign forms. It should be limited to bed rest, analgesics and sedatives. In severe cases, supra-sternal drainage permits decompression of the mediastinum. The physiopathological mechanisms are discussed, but the usually accepted theory is rupture of an alveolus into the pulmonary interstitial tissue. The pressure gradient necessary for this rupture may be due to variations in alveolar or vascular pressure. PMID:170684

  19. Diesel Emission Control -- Sulfur Effects (DECSE) Program; Phase I Interim Data Report No. 1

    SciTech Connect

    DOE; ORNL; NREL; EMA; MECA

    1999-08-15

    The Diesel Emission Control-Sulfur Effects (DECSE) is a joint government/industry program to determine the impact of diesel fuel sulfur levels on emission control systems whose use could lower emissions of nitrogen oxides (NO{sub x}) and particulate matter (PM) from on-highway trucks in the 2002--2004 model years. Phase 1 of the program was developed with the following objectives in mind: (1) evaluate the effects of varying the level of sulfur content in the fuel on the emission reduction performance of four emission control technologies; and (2) measure and compare the effects of up to 250 hours of aging on selected devices for multiple levels of fuel sulfur content. This interim data report summarizes results as of August, 1999, on the status of the test programs being conducted on three technologies: lean-NO{sub x} catalysts, diesel particulate filters and diesel oxidation catalysts.

  20. Fuel consumptions and exhaust emissions induced by cooperative adaptive cruise control strategies

    NASA Astrophysics Data System (ADS)

    Yu, Shaowei; Shi, Zhongke

    2015-04-01

    Many cooperative adaptive cruise control strategies have been presented to improve traffic efficiency as well as road traffic safety, but scholars have rarely explored the impacts of these strategies on cars' fuel consumptions and exhaust emissions. In this paper, we respectively select two-velocity difference model, multiple velocity difference model and the car-following model considering multiple preceding cars' accelerations to investigate each car's fuel consumptions, carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOX) emissions and carry out comparative analysis. The comparisons of fuel consumptions and exhaust emissions in three different cruise control strategies show that cooperative cars simulated by the car-following model considering multiple preceding cars' accelerations can run with the minimal fuel consumptions, CO, HC and NOX emissions, thus, taking the car-following model considering multiple preceding cars' accelerations as the cooperative adaptive cruise control strategy can significantly improve cars' fuel efficiency and exhaust emissions.

  1. Control techniques for volatile organic compound emissions from stationary sources, December 1992. Final report

    SciTech Connect

    Not Available

    1992-12-01

    The document is a summary document containing general information on sources of volatile organic compound (VOC) emissions, applicable control techniques, and the impacts resulting from control applications. It references other documents which contain much more detailed information on individual sources and control techniques. This is the third edition of a report originally published by the Department of Health, Education, and Welfare (HEW) titled, 'Control Techniques for Hydrocarbon and Organic Solvent Emissions from Stationary Sources (AP-68).' The first edition was published in March 1970 by the National Air Pollution Control Administration, a part of HEW.

  2. High-Capacity Sulfur Dioxide Absorbents for Diesel Emissions Control

    SciTech Connect

    Li, Liyu; King, David L.

    2005-01-05

    High capacity sulfur dioxide absorbents based on manganese oxide octahedral molecular sieves (OMS) have been identified. These materials are based on MnO6 octahedra sharing faces and edges to form various tunnel structures (2x2, 2x3, 2x4, 3x3) differentiated by the number of octahedra on a side. The SO2 capacities of these materials, measured at 325 C with a feed containing 250 ppmv SO2 in air, are as high as 70wt% (wt/wt), remarkably higher than conventional metal oxide-based SO2 absorbents. Among the OMS materials the 2x2 member, cryptomelane, exhibits the highest capacity and adsorption rate. Its SO2 absorption behavior has been further characterized as a function of temperature, space velocity, and feed composition. The dominant pathway for SO2 absorption is through the oxidation of SO2 to SO3 by Mn4+ followed by SO3 reaction with Mn2+ to form MnSO4. Absorption can occur in the absence of gas phase oxygen, with a moderate loss in overall capacity. The inclusion of reducible gases NO and CO in the feed does not reduce SO2 capacity. The absorption capacity decreases at high space velocity and lower absorption temperature, indicating the important role of diffusion of sulfate from the surface to the bulk of the material in order to reach full capacity. A color change of cryptomelane from black to yellow-brown after SO2 absorption can be used as an indicator of absorption progress. Cryptomelane can be synthesized using MnSO4 as a reagent. Therefore, after full SO2 absorption the product MnSO4 can be re-used as raw material for a subsequent cryptomelane synthesis. Cryptomelane has a similarly high capacity toward SO3, therefore it can be used for removal of all SOx species generated from a variety of combustion sources. Cryptomelane may find application as a replaceable absorbent for the removal of SOx from diesel truck exhaust, protecting downstream emissions control devices such as particulate filters and NOx traps.

  3. Effects of engineering controls on radioactive air emissions from the Los Alamos Neutron Science Center 

    E-print Network

    Fuehne, David Patrick

    1996-01-01

    the effectiveness of these emissions control efforts. Using a flow-through ionization chamber and high-purity germanium (HPGE) detector, the delay line was shown to reduce overall facility emissions by 29%. The scrubber effectiveness at removing tritium was found...

  4. Texas Air Control Board's point source emission inventory data collection and management for 1980

    Microsoft Academic Search

    C. Snow; J. Panketh

    1982-01-01

    This paper describes the extensive effort that was expended by the emissions inventory staff at the Texas Air Control Board in successfully managing the emissions inventory data collection and automation of approximately 800 major sources in Texas. An important characteristic in this effort was the close coordination between the EI staff, regional and local program staff, and the industrial representatives

  5. ADDENDUM TO ASSESSMENT OF STYRENE EMISSION CONTROLS FOR FRP/C AND BOAT BUILDING INDUSTRIES

    EPA Science Inventory

    This report is an addendum to a 1996 report, Assessment of Styrene Emission Controls for FRP/C and Boat Building Industries. It presents additional evaluation of the biological treatment of styrene emissions, Dow Chemical Company's Sorbathene solvent vapor recovery system, Occupa...

  6. Soil physiochemical controls on trace gas emissions for a North Dakota mollisol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantification of trace gas emissions and an increased understanding of soil controls on emissions during freeze-thaw cycles are essential to refine climate change models. Six similar, intact soil cores were collected to a depth of 80 cm from an undisturbed prairie in central North Dakota. Trace g...

  7. Using functional data analysis of diurnal ozone and NOx cycles to inform transportation emissions control

    Microsoft Academic Search

    H. Oliver Gao; Debbie A. Niemeier

    2008-01-01

    Ozone pollution is caused by photochemical reactions of precursor volatile organic compounds and nitrogen oxides, of which transportation emissions are the single major source. Understanding the complexity of diurnal ozone processes and their relationships with precursors is thus critical for identifying optimal transportation emissions control strategies. This paper uses functional data analysis methods to model the dynamics of diurnal ozone

  8. EMISSION TESTING AND EVALUATION OF FORD/KOPPERS COKE PUSHING CONTROL SYSTEM. VOLUME II. APPENDICES

    EPA Science Inventory

    The report documents a field testing and engineering evaluation of the performance of a retrofitted, mobile-hood, high-energy-scrubber control system, abating coke-side pushing emissions from a 58-oven coke battery. It documents the venturi-scrubber inlet and outlet emission rate...

  9. EMISSION TESTING AND EVALUATION OF FORD/KOPPERS COKE PUSHING CONTROL SYSTEM. VOLUME I. FINAL REPORT

    EPA Science Inventory

    The report documents a field testing and engineering evaluation of the performance of a retrofitted, mobile-hood, high-energy-scrubber control system, abating coke-side pushing emissions from a 58-oven coke battery. It documents the venturi-scrubber inlet and outlet emission rate...

  10. Hydrological controls on nitrous oxide and carbon dioxide emissions across an agricultural landscape

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Changes in hydrological controls on soil greenhouse gas emissions could result in important climate change feedbacks. Water table fluctuations into surface soils are “hot moments” of soil CO2 and N2O emissions. Future global change may affect the frequency and magnitude of water table fluctuations...

  11. Assessment of methods for methyl iodide emission reduction and pest control using a simulation model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Various methods have been developed to reduce atmospheric emissions from the agricultural use of highly volatile pesticides and mitigate their adverse environmental effects. The effectiveness of various methods on emissions reduction and pest control was assessed using simulation model in this study...

  12. PARTICULATE EMISSION MEASUREMENTS FROM CONTROLLED CONSTRUCTION ACTIVITIES (EPA/600/R-01/031)

    EPA Science Inventory

    This report summarizes the results of field testing of the effectiveness of control measures for sources of fugitive particulate emissions found at construction sites. Tests of the effectiveness of watering of temporary unpaved travel surfaces on PM-10 emissions were per...

  13. 40 CFR 75.34 - Units with add-on emission controls.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...in section 2.1.2.1(b) of appendix A to this part, except that the words “maximum potential NOX emission rate (MER)” shall be replaced with the words “maximum controlled NOX emission rate (MCR)” and the NOX MEC shall be used...

  14. 40 CFR 75.34 - Units with add-on emission controls.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...in section 2.1.2.1(b) of appendix A to this part, except that the words “maximum potential NOX emission rate (MER)” shall be replaced with the words “maximum controlled NOX emission rate (MCR)” and the NOX MEC shall be used...

  15. 40 CFR 75.34 - Units with add-on emission controls.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...in section 2.1.2.1(b) of appendix A to this part, except that the words “maximum potential NOX emission rate (MER)” shall be replaced with the words “maximum controlled NOX emission rate (MCR)” and the NOX MEC shall be used...

  16. Control of air toxin particulate and vapor emissions after coal combustion utilizing calcium magnesium acetate

    Microsoft Academic Search

    Judith Irene Shuckerow; Judith Anne Steciak; Donald L. Wise; Yiannis A. Levendis; Girard A. Simons; Joseph D. Gresser; Edgar B. Gutoff; C. David Livengood

    1996-01-01

    Major environmental issues are now coming to the forefront in all parts of the globe with increased public awareness of the human health effects and the possible effects on our global environment. Modern control technologies, when implemented, have significantly reduced air pollution emissions that are a result of coal combustion during this century. However, the emissions have not been completely

  17. ASSESSMENT OF STYRENE EMISSION CONTROLS FOR FRP/C AND BOAT BUILDING INDUSTRIES

    EPA Science Inventory

    The report gives results of an evaluation of several conventional and novel emission control technologies that have been used or could be used to treat styrene emissions from open molding processes in fiberglass-reinforced plastics/composites (FRP/C) and fiberglass boat building ...

  18. CONTROL OF NOX EMISSIONS FROM U.S. COAL-FIRED ELECTRIC UTILITY BOILERS

    EPA Science Inventory

    The paper discusses the control of nitrogen oxide (NOx) emissions from U.S. coal-fired electric utility boilers. (NOTE: In general, NOx control technologies are categorized as being either primary or secondary control technologies. Primary technologies reduce the amount of NOx pr...

  19. 40 CFR 63.2343 - What are my requirements for emission sources not requiring control?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...emission sources not requiring control? This section establishes...2338 that do not require control under this subpart (i...plant site plan or process and instrumentation diagram (P&ID). ...more that is not subject to control based on the criteria...

  20. 40 CFR 63.2343 - What are my requirements for emission sources not requiring control?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...emission sources not requiring control? This section establishes...2338 that do not require control under this subpart (i...plant site plan or process and instrumentation diagram (P&ID). ...more that is not subject to control based on the criteria...

  1. 40 CFR 63.2343 - What are my requirements for emission sources not requiring control?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...emission sources not requiring control? This section establishes...2338 that do not require control under this subpart (i...plant site plan or process and instrumentation diagram (P&ID). ...more that is not subject to control based on the criteria...

  2. 40 CFR 63.2343 - What are my requirements for emission sources not requiring control?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...emission sources not requiring control? This section establishes...2338 that do not require control under this subpart (i...plant site plan or process and instrumentation diagram (P&ID). ...more that is not subject to control based on the criteria...

  3. 40 CFR 63.2343 - What are my requirements for emission sources not requiring control?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...emission sources not requiring control? This section establishes...2338 that do not require control under this subpart (i...plant site plan or process and instrumentation diagram (P&ID). ...more that is not subject to control based on the criteria...

  4. Multi-objective optimisation of wastewater treatment plant control to reduce greenhouse gas emissions.

    PubMed

    Sweetapple, Christine; Fu, Guangtao; Butler, David

    2014-05-15

    This study investigates the potential of control strategy optimisation for the reduction of operational greenhouse gas emissions from wastewater treatment in a cost-effective manner, and demonstrates that significant improvements can be realised. A multi-objective evolutionary algorithm, NSGA-II, is used to derive sets of Pareto optimal operational and control parameter values for an activated sludge wastewater treatment plant, with objectives including minimisation of greenhouse gas emissions, operational costs and effluent pollutant concentrations, subject to legislative compliance. Different problem formulations are explored, to identify the most effective approach to emissions reduction, and the sets of optimal solutions enable identification of trade-offs between conflicting objectives. It is found that multi-objective optimisation can facilitate a significant reduction in greenhouse gas emissions without the need for plant redesign or modification of the control strategy layout, but there are trade-offs to consider: most importantly, if operational costs are not to be increased, reduction of greenhouse gas emissions is likely to incur an increase in effluent ammonia and total nitrogen concentrations. Design of control strategies for a high effluent quality and low costs alone is likely to result in an inadvertent increase in greenhouse gas emissions, so it is of key importance that effects on emissions are considered in control strategy development and optimisation. PMID:24602860

  5. CAPSULE REPORT: SOURCES AND AIR EMISSION CONTROL TECHNOLOGIES AT WASTE MANAGEMENT FACILITIES

    EPA Science Inventory

    The chemicals processed during waste management operations can volatilize into the atmosphere and cause carcinogenic or other toxic effects or contribute to ozone formation. Regulations have been developed to control air emissions from these operations. The EPA has promulgated st...

  6. Emission Control and Elimination Through The Use Of Condensation and Heat Recovery Technologies- A Case Study

    E-print Network

    Madewell, A. E.; Bullock, W. N.

    -scale solvent drying processes that emit volatile organic compounds (VOC's). These exhausts could be recirculated for the purposes of emission point elimination, heat recovery and solvent reuse. The aim was to create an environmental control process which would...

  7. KEY PUBLICATIONS (EMISSIONS CHARACTERIZATION AND PREVENTION BRANCH, AIR POLLUTION PREVENTION AND CONTROL DIVISION, NRMRL)

    EPA Science Inventory

    The Emissions Characterization and Prevention Branch (ECPB) of NRMRL's Air Pollution Prevention and Control Division in Research Triangle Park, NC, produces highly specialized scientific and technical documents relating to ECPB's research areas. A list of key publications coveri...

  8. CONTROL OF UTILITY BOILER AND GAS TURBINE POLLUTANT EMISSIONS BY COMBUSTION MODIFICATION - PHASE I

    EPA Science Inventory

    The report gives results of a field study to assess the applicability of combustion modification techniques to control NOx and other pollutant emissions from utility boilers and gas turbines without causing deleterious side effects. Comprehensive, statistically designed tests wer...

  9. PSO-2005 FU-5206 final report Emission control by sulphur addition

    E-print Network

    PSO-2005 FU-5206 final report Emission control by sulphur addition Jesper Ahrenfeldt Jimmy Andersen for CO/H2 is analyzed with and without addition of sulfur. Based on the work on this chemistry in the PSO

  10. CONTROL OF PCDD/PCDF EMISSIONS FROM MUNICIPAL WASTE COMBUSTION SYSTEMS

    EPA Science Inventory

    The article gives results of tests on five modern municipal waste combustors (MWCs) to characterize or determine the performance of representative combustor types and associated air emission control systems in the regulatory development process. est results for uncontrolled (comb...

  11. CONTROL OF PCDD/PCDF EMISSIONS FROM MUNICIPAL WASTE COMBUSTION SYSTEMS

    EPA Science Inventory

    The article gives results of tests on five modern municipal waste combustors (MWCs) to characterize or determine the performance of representative combustor types and associated air emission control systems in the regulatory development process. Test results for uncontrolled (com...

  12. Randomized controlled trial of probiotics for the prevention of spontaneous preterm delivery associated with intrauterine infection: study protocol

    PubMed Central

    2010-01-01

    Background Spontaneous preterm deliveries that occur before the 34th week of gestation, and particularly before the 32nd week of gestation, have been strongly associated to intrauterine infection, ascending from vagina, and represent the largest portion of neonatal deaths and neurological problems. Bacterial vaginosis, characterized by a diminished or absent flora of lactobacilli and increased colonization of several anaerobic or facultative microorganisms, increases two times the risk of preterm delivery before the 34th week. Trials of antibiotics failed to show efficacy and effectiveness against spontaneous preterm birth related to bacterial vaginosis. Some studies indicate benefit from selected probiotics to treat genitourinary infections, including bacterial vaginosis. Objective The purpose of this study is to evaluate the effectiveness of the early administration of selected probiotics to pregnant women with asymptomatic bacterial vaginosis/intermediate degree infection to reduce the occurrence of spontaneous preterm delivery and related neonatal mortality and morbidity. Methods/Design Women attending public prenatal care services in Rio de Janeiro will be screened to select asymptomatic pregnant women, less than 20 weeks' gestation, with no indication of elective preterm delivery. Those with vaginal pH > = 4.5 and a Nugent score between 4 and 10 (intermediate degree infection or bacterial vaginosis) will be randomized to either the placebo or the intervention group, after written informed consent. Intervention consists in the use of probiotics, Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14, 2 capsules a day, each capsule containing more than one million bacilli of each strain, for 6-12 weeks, up to the 24th-25th wk of gestation. Ancillary analyses include quantification of selected cervicovaginal cytokines and genotyping of selected polymorphisms. The randomization process is stratified for history of preterm delivery and blocked. Allocation concealment was designed as well as blinding of women, caregivers and outcome evaluators. The study will be supervised by an independent monitoring committee. Outcomes under study are preterm delivery (< 34- < 32 weeks of gestation) and associated neonatal complications: early neonatal sepsis, bronchopulmonary dysplasia, periventricular leukomalacia, necrotizing enterocolitis, and prematurity-related retinopathy; definitions were adapted from those recommended by the 2002 version of the Vermont-Oxford Network. Trial registration at NIH register: NCT00303082. PMID:20591191

  13. Fast-regenerable sulfur dioxide adsorbents for diesel engine emission control

    DOEpatents

    Li, Liyu [Richland, WA; King, David L [Richland, WA

    2011-03-15

    Disclosed herein are sorbents and devices for controlling sulfur oxides emissions as well as systems including such sorbents and devices. Also disclosed are methods for making and using the disclosed sorbents, devices and systems. In one embodiment the disclosed sorbents can be conveniently regenerated, such as under normal exhaust stream from a combustion engine, particularly a diesel engine. Accordingly, also disclosed are combustion vehicles equipped with sulfur dioxide emission control devices.

  14. Main resonances in directly modulated semiconductor lasers: effect of spontaneous

    E-print Network

    Toral, Raúl

    Main resonances in directly modulated semiconductor lasers: effect of spontaneous emission and gain saddle-node bifurcations related to the main resonances in pump-modulated laser diodes are obtained via] and of the spontaneous emission terms [lo] have already been considered, but little attention has been given to main

  15. Spontaneous Oscillation by Hair Bundles of the Bullfrog's Sacculus

    Microsoft Academic Search

    Pascal Martin; D. Bozovic; Y. Choe; A. J. Hudspeth

    2003-01-01

    One prominent manifestation of mechanical activity in hair cells is spontaneous otoacoustic emission, the unprovoked emanation of sound by an internal ear. Because active hair bundle motility probably constitutes the active process of nonmammalian hair cells, we investigated the ability of hair bundles in the bullfrog's sacculus to produce oscillations that might underlie spontaneous otoacoustic emissions. When maintained in the

  16. VOC Emission Control with the Brayton Cycle Pilot Plant Operations 

    E-print Network

    Enneking, J. C.

    1992-01-01

    A mobile pilot plant capable of removing VOC emissions from exhaust air streams was cooperatively funded by SCE, EPRI, 3M, and NUCON. Valuable information about the process and the recovery operation has been gained by performing tests at a number...

  17. Intertemporal Permit Trading for the Control of Greenhouse Gas Emissions

    Microsoft Academic Search

    PAUL LEIBY; JONATHAN RUBIN

    2008-01-01

    This paper integrates two themes in the intertemporal permit literature through the con- struction of an intertemporal banking system for a pollutant that creates both stock and flow damages. A permit banking system for the special case of a pollutant that only causes stock damages is also developed. This latter, simpler case corresponds roughly to the greenhouse gas emission reduction

  18. Diesel fuel burner for diesel emissions control system

    DOEpatents

    Webb, Cynthia C.; Mathis, Jeffrey A.

    2006-04-25

    A burner for use in the emissions system of a lean burn internal combustion engine. The burner has a special burner head that enhances atomization of the burner fuel. Its combustion chamber is designed to be submersed in the engine exhaust line so that engine exhaust flows over the outer surface of the combustion chamber, thereby providing efficient heat transfer.

  19. Iodine emission from separations processes and flowsheets for improved emission control

    Microsoft Academic Search

    1955-01-01

    Silver reactors were installed at the BiPOâ plants in 1950 and were included in the Redox and Purex designs. Prior emissions were of the order of 30 to 40 curies per day and the reactors were intended to achieve ''reasonable'' levels of less than 10 curies per day. At that time a level of 1 curie per day per plant

  20. Modeling Nitrous Oxide emissions and identifying emission controlling factors for a spruce forest ecosystem on drained organic soil

    NASA Astrophysics Data System (ADS)

    He, Hongxing; Kasimir, Åsa; Jansson, Per-Erik; Svensson, Magnus; Meyer, Astrid; Klemedtsson, Leif

    2015-04-01

    High Nitrous Oxide (N2O) emission has been identified in hemiboreal forests on drained organic soils. However, the controlling factors regulating the emissions have been unclear. To examine the importance of different factors on the N2O emission in a spruce forest on drained organic soil, a process-based model, CoupModel, was calibrated by the generalized likelihood uncertainty estimation (GLUE) method. The calibrated model reproduced most of the high resolution data (total net radiation, soil temperature, groundwater level, net ecosystem exchange, etc.) very well, as well as accumulated measured N2O emissions, but showed difficulties to capture all the measured emission peaks. Parameter uncertainties could be reduced by combining selected criteria with the measurement data. The model showed the N2O emissions during the summer to be controlled mainly by the competition between plants and microbes while during the winter season snow melt periods are important. The simulated N budget shows >100 kg N ha-1 yr-1 to be in circulation between soil and plants and back again. Each year the peat mineralization adds about 60 kg N ha-1 and atmospheric deposition 12 kg N ha-1. Most of the mineralized litter and peat N is directly taken up by the plants but only a part accumulates in the plant biomass. As long as no timber is harvested the main N loss from the system is through nitrate leaching (30 kg N ha-1 yr-1) and gas emissions (20 kg N ha-1 yr-1), 55% as NO, 27% as N2O and 18% as N2. Regarding N2O gas emissions, our modeling indicates denitrification to be the most responsible process, of the size 6 kg N ha-1 yr-1, which could be compared to 0.04 kg N ha-1 yr-1 from nitrification. Our modelling also reveal 88% of the N2O mainly to be produced by denitrification in the capillary fringe (c.a. 40-60 cm below soil surface) of the anaerobic zone using nitrate produced in the upper more aerobic layers. We conclude N2O production/emission to be controlled mainly by the complex interaction between soil N availability, mediated by mineralization, nitrification, and plant growth together with soil anaerobicity controlled by the groundwater level. The model is currently used for modelling greenhouse gas emissions from drained organic soils over the entire forest cycle, from plantation to harvest. Different land use and plant production are compared like Spruce, Willow and Reed Canary Grass as well as rewetting options. This work was funded by the Swedish Energy Agency and conducted within the research programs BECC (Biodiversity and Ecosystem services in a Changing Climate) and LAGGE (Landscape and Greenhouse Gas Exchange).

  1. Integrated emissions control system for residential CWS furnace. Final report, September 20, 1989--March 20, 1993

    SciTech Connect

    Breault, R.W.; McLarnon, C.

    1993-03-01

    One of the major obstacles to the successful development and commercialization of a coal-fired residential furnace is the need for a reliable, cost-effective emission control system. Tecogen is developing a novel, integrated control system to control NO{sub x}SO{sub 2}, and particulate emissions. At the heart of this system is a unique emissions control reactor for the control of SO{sub 2}. This reactor provides high sorbent particle residence time within the reactor while doing so in a very compact geometry. Final cleanup of any fine particulates exiting the reactor including respirable-sized particulates, is completed with the use of high efficiency bag filters. Under a previous contract with PETC (Contract No. DE-AC22-87PC79650), Tecogen developed a residential-scale Coal Water Slurry (CWS) combustor to control NO{sub x}emission. This combustor makes use of centrifugal forces, set up by a predominantly tangential flow field, to separate and confine larger unburned coal particles in the furnace upper chamber. Various partitions are used to retard the axial, downward flow of these particles, and thus maximize their residence time in the hottest section of the combustor. By operating this combustor under staged conditions, the local stoichiometry in the primary zone can be controlled in such a manner as to minimize NO{sub x} emission.

  2. Emission control from stationary power sources (environmental assessment field testing: effects of NO\\/sub x\\/ controls applied to a tangential coal-fired utility boiler)

    Microsoft Academic Search

    E. B. Higginbotham; L. R. Waterland; H. B. Mason; R. E. Hall

    1980-01-01

    A field testing program was conducted to measure changes in multimedia emissions from a tangential coal-fired utility boiler as a result of applying combustion modification nitrogen oxides control. Emissions of trace elements, organic materials, sulfur species, carbon monoxide, sulfur dioxide, and nitrogen oxides were measured. Particulate and sulfur species emissions were not affected by combustion modification. Organic material emissions increased

  3. Mercury Emissions Control Technologies (released in AEO2006)

    EIA Publications

    2006-01-01

    The Annual Energy Outlook 2006 reference case assumes that states will comply with the requirements of the Environmental Protection Agency's new Clean Air Mercury Rule (CAMR) regulation. CAMR is a two-phase program, with a Phase I cap of 38 tons of mercury emitted from all U.S. power plants in 2010 and a Phase II cap of 15 tons in 2018. Mercury emissions in the electricity generation sector in 2003 are estimated at around 50 tons. Generators have a variety of options to meet the mercury limits, such as: switching to coal with a lower mercury content, relying on flue gas desulfurization or selective catalytic reduction equipment to reduce mercury emissions, or installing conventional activated carbon injection (ACI) technology.

  4. Physical Sciences Facility Air Emission Control Equivalency Evaluation

    SciTech Connect

    Brown, David M.; Belew, Shan T.

    2008-10-17

    This document presents the adequacy evaluation for the application of technology standards during design, fabrication, installation and testing of radioactive air exhaust systems at the Physical Sciences Facility (PSF), located on the Horn Rapids Triangle north of the Pacific Northwest National Laboratory (PNNL) complex. The analysis specifically covers the exhaust portion of the heating, ventilation and air conditioning (HVAC) systems associated with emission units EP-3410-01-S, EP-3420-01-S and EP 3430-01-S.

  5. Controlling automotive exhaust emissions: successes and underlying science

    Microsoft Academic Search

    Martyn V. Twigg

    2005-01-01

    Photochemical reactions of vehicle exhaust pollutants were responsible for photochemical smog in many cities during the 1960s and 1970s. Engine improvements helped, but additional measures were needed to achieve legislated emissions levels. First oxidation catalysts lowered hydrocarbon and carbon monoxide, and later nitrogen oxides were reduced to nitrogen in a two-stage process. By the 1980s, exhaust gas could be kept

  6. Direct Observation of the Spontaneous Emission of the Hyperfine Transition {ital F}{bold =4} to {ital F}{bold =3} in Ground State Hydrogenlike {sup {bold 165}}Ho{sup {bold 66+}} in an Electron Beam Ion Trap

    SciTech Connect

    Crespo Lopez-Urrutia, J.R.; Beiersdorfer, P.; Savin, D.; Widmann, K. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    1996-07-01

    We report the first direct laboratory measurement of the spontaneous emission due to the hyperfine splitting of the ground state of a highly charged hydrogenlike ion excited by electron collisions. The transition between the {ital F}=4 and {ital F}=3 levels of the 1{ital s}{sup 2}{ital S}{sub 1/2} configuration of hydrogenlike {sup 165}Ho{sup 65+} was observed and its wavelength was determined to 5726.4{plus_minus}1.5. After taking into account relativistic, nuclear charge distribution, Bohr-Weisskopf, and QED corrections, we observe a significant deviation from commonly tabulated values of the nuclear dipole magnetic moment of this nucleus. {copyright} {ital 1996 The American Physical Society.}

  7. A pulsed source for Xe(6s[3\\/2]1) and Xe(6s?[1\\/2]1) resonance state atoms using two-photon driven amplified spontaneous emission from the Xe(6p) and Xe(6p?) states

    Microsoft Academic Search

    V. A. Alekseev; D. W. Setser

    1996-01-01

    A new, simple method for the generation of Xe(6s[3\\/2]1) and Xe(6s?[1\\/2]1) atoms is described. The method involves resonant two-photon excitation of Xe(6p[1\\/2]0 and 6p?[3\\/2]2) states followed by amplified spontaneous emission (ASE) to the Xe(6s[3\\/2]1 and 6s?[1\\/2]1) states. The vacuum ultraviolet transitions, Xe(6s[3\\/2]1?5p6(1S0)) at 147 nm and Xe(6s?[1\\/2]1?5p6(1S0)) at 129.6 nm, were used to monitor the time dependence of the resonance

  8. [Control levels of Sin3 histone deacetylase for spontaneous and UV-induced mutagenesis in yeasts Saccharomyces cerevisiae].

    PubMed

    Lebovka, I Iu; Kozhina, T N; Fedorova, I V; Peshekhonov, V T; Evstiukhina, T A; Chernenkov, A Iu; Korolev, V G

    2014-01-01

    SIN3 gene product operates as a repressor for a huge amount of genes in Saccharomyces cerevisiae. Sin3 protein with a mass of about 175 kDa is a member of the RPD3 protein complex with an assessed mass of greater than 2 million Da. It was previously shownthat RPD3 gene mutations influence recombination and repair processes in S. cerevisiae yeasts. We studied the impacts of the sin3 mutation on UV-light sensitivity and UV-induced mutagenesis in budding yeast cells. The deletion ofthe SIN3 gene causes weak UV-sensitivity of mutant budding cells as compared to the wild-type strain. These results show that the sin3 mutation decreases both spontaneous and UV-induced levels of levels. This fact is hypothetically related to themalfunction of ribonucleotide reductase activity regulation, which leads to a decrease in the dNTP pool and the inaccurate error-prone damage bypass postreplication repair pathway, which in turn provokes a reduction in the incidence of mutations. PMID:25711007

  9. Controlled Ultrasound-Induced Blood-Brain Barrier Disruption Using Passive Acoustic Emissions Monitoring

    PubMed Central

    Arvanitis, Costas D.; Livingstone, Margaret S.; Vykhodtseva, Natalia; McDannold, Nathan

    2012-01-01

    The ability of ultrasonically-induced oscillations of circulating microbubbles to permeabilize vascular barriers such as the blood-brain barrier (BBB) holds great promise for noninvasive targeted drug delivery. A major issue has been a lack of control over the procedure to ensure both safe and effective treatment. Here, we evaluated the use of passively-recorded acoustic emissions as a means to achieve this control. An acoustic emissions monitoring system was constructed and integrated into a clinical transcranial MRI-guided focused ultrasound system. Recordings were analyzed using a spectroscopic method that isolates the acoustic emissions caused by the microbubbles during sonication. This analysis characterized and quantified harmonic oscillations that occur when the BBB is disrupted, and broadband emissions that occur when tissue damage occurs. After validating the system's performance in pilot studies that explored a wide range of exposure levels, the measurements were used to control the ultrasound exposure level during transcranial sonications at 104 volumes over 22 weekly sessions in four macaques. We found that increasing the exposure level until a large harmonic emissions signal was observed was an effective means to ensure BBB disruption without broadband emissions. We had a success rate of 96% in inducing BBB disruption as measured by in contrast-enhanced MRI, and we detected broadband emissions in less than 0.2% of the applied bursts. The magnitude of the harmonic emissions signals was significantly (P<0.001) larger for sonications where BBB disruption was detected, and it correlated with BBB permeabilization as indicated by the magnitude of the MRI signal enhancement after MRI contrast administration (R2?=?0.78). Overall, the results indicate that harmonic emissions can be a used to control focused ultrasound-induced BBB disruption. These results are promising for clinical translation of this technology. PMID:23029240

  10. Photo-induced microstructured polymers for the optimisation and control of organic devices emission properties

    Microsoft Academic Search

    Licinio Rocha; Vincent Dumarcher; Eymeric Malcor; Céline Fiorini; Christine Denis; Paul Raimond; Bernard Geffroy; Jean-Michel Nunzi

    2002-01-01

    Patterning and microstructuring of functional polymers is a key process in order to control the emission properties of polymer thin films towards the design and realisation of devices such as electroluminescent diodes (OLEDs) or organic lasers. We present an original method for the realisation of periodic structures in the visible wavelength region using laser controlled molecular motion. The optical pumping

  11. PERFORMANCE AND COST OF MERCURY AND MULTIPOLLUTANT EMISSION CONTROL TECHNOLOGY APPLICATIONS ON ELECTRIC UTILITY BOILERS

    EPA Science Inventory

    The report presents estimates of the performance and cost of both powdered activated carbon (PAC) and multipollutant control technologies that may be useful in controlling mercury emissions. Based on currently available data, cost estimates for PAC injection range are 0.03-3.096 ...

  12. CONTROL OF HYDROCARBON EMISSIONS FROM COTTON AND SYNTHETIC TEXTILE FINISHING PLANTS

    EPA Science Inventory

    The report gives results of an evaluation of the applicability and economics of emissions control technologies for the abatement of volatile organic compounds emanating from cotton and synthetic textile finishing plants. A survey of the state-of-the-art and control technologies d...

  13. A distributed process control system for the Tritium Emissions Reduction Facility

    Microsoft Academic Search

    T. J. Kissner; R. E. Wieneke

    1991-01-01

    The Tritium Emissions Reduction Facility (TERF) is an automated process that continuously removes tritium from process gases before they are discharged to the atmosphere. Key control parameters include: temperature, pressure, flow, oxygen content, total combustibles, moisture concentrations and tritium concentrations. The procurement of an industrial, microprocessor-based Distributed Process Control System was justified for TERF due to the critical nature and

  14. A distributed process control system for the tritium emissions reduction facility

    Microsoft Academic Search

    T. J. Kissner; R. E. Wieneke

    1992-01-01

    This paper reports on the Tritium Emissions Reduction Facility (TERF) which is an automated process that continuously removes tritium from process gases before they are discharged to the atmosphere. Key control parameters include: temperature, pressure, flow, oxygen content, total combustibles, moisture concentrations and tritium concentrations. The procurement of an industrial, microprocessor-based Distributed Process Control System was justified for TERF due

  15. Control of volatile organic emissions from petroleum liquid storage in external floating roof tanks

    Microsoft Academic Search

    R. K. Burr; K. C. Brothers; J. G. Wright

    1978-01-01

    This report provides the necessary guidance for development of regulations limiting emissions of volatile organic compounds (VOC) from storage of petroleum liquids in external floating roof tanks. Reasonably available control technology (RACT) is defined in this document; cost analysis for RACT is included for evaluating the cost effectiveness of controlling external floating roof tank sources.

  16. Investigation of Selective Catalytic Reduction Impact on Mercury Speciation under Simulated NOx Emission Control Conditions

    Microsoft Academic Search

    Chun W. Lee; Ravi K. Srivastava; S. Behrooz Ghorishi; Thomas W. Hastings; Frank M. Stevens

    2004-01-01

    Selective catalytic reduction (SCR) technology increasingly is being applied for controlling emissions of nitrogen oxides (NOx) from coal-fired boilers. Some recent field and pilot studies suggest that the operation of SCR could affect the chemical form of mercury (Hg) in coal combustion flue gases. The speciation of Hg is an important factor influencing the control and environmental fate of Hg

  17. Study of Speciation of Mercury under Simulated SCR NOx Emission Control Conditions

    Microsoft Academic Search

    Chun W. Lee; Ravi K. Srivastava; S. Behrooz Ghorishi; Thomas W. Hastings; Frank M. Stevens

    Selective catalytic reduction (SCR) technology is being increasingly applied for controlling emissions of nitrogen oxides (NOx) from coal-fired boilers. Some recent field and pilot studies suggest that the operation of SCR could affect the chemical form of mercury species (speciation) in the coal combustion flue gases. The speciation of mercury is an important factor that influences the control and environmental

  18. New experimental device for infrared spectral directional emissivity measurements in a controlled environment

    NASA Astrophysics Data System (ADS)

    del Campo, Leire; Pérez-Sáez, Raúl B.; Esquisabel, Xabier; Fernández, Ignacio; Tello, Manuel J.

    2006-11-01

    A new experimental device for infrared spectral directional emissivity measurements in a controlled atmosphere is presented. The sample holder, which permits to measure spectral directional emissivity up to 1050K, is placed inside a stainless steel sample chamber that can be evacuated or filled with different gases. The signal detection is carried out by means of a Fourier transform infrared spectrometer. The experimental results focus on the capability of the device to perform emissivity measurements as a function of temperature, emission angle, and in situ surface state evolution. A careful study of the sample temperature homogeneity and the measurement method has been done, including the background radiation, the apparatus response function, and temperature differences between the sample and the blackbody radiator. As a consequence, a compact expression for the sample emissivity that generalizes those previously obtained for the direct radiometric measurement method is found. The error assessment shows that the main contribution to the emissivity uncertainty is related to the sample temperature. The overall uncertainty at intermediate temperature is estimated to be around 3% at short wavelengths. Emissivity measurements of Armco iron were used in order to check the accuracy of the experimental device. The experimental results show an excellent fit with direct emissivity data accessible in the literature, as well as with the theoretical emissivity obtained from the Hagen-Rubens relation.

  19. DEMONSTRATION OF AN ADVANCED INTEGRATED CONTROL SYSTEM FOR SIMULTANEOUS EMISSIONS REDUCTION

    SciTech Connect

    Suzanne Shea; Randhir Sehgal; Ilga Celmins; Andrew Maxson

    2002-02-01

    The primary objective of the project titled ''Demonstration of an Advanced Integrated Control System for Simultaneous Emissions Reduction'' was to demonstrate at proof-of-concept scale the use of an online software package, the ''Plant Environmental and Cost Optimization System'' (PECOS), to optimize the operation of coal-fired power plants by economically controlling all emissions simultaneously. It combines physical models, neural networks, and fuzzy logic control to provide both optimal least-cost boiler setpoints to the boiler operators in the control room, as well as optimal coal blending recommendations designed to reduce fuel costs and fuel-related derates. The goal of the project was to demonstrate that use of PECOS would enable coal-fired power plants to make more economic use of U.S. coals while reducing emissions.

  20. Heavy metals emission from controlled combustion of PVC 

    E-print Network

    El-Ayyoubi, Mohammed A.

    1989-01-01

    14 emissions when excited (23). The AAS determination of most heavy metals is remarkably selective and sensitive. Lower detection limits, using concentrations in a a lean a)r ? acetylene flame, are down to 0. 7 to 2 ng/ml for cadmium, and 0. 01... situations. Extremely toxic heavy metals such as, cadmium, lead, and antimony were found in major and minor concentrations in more than half of the plastic materials analyzed. Moreover, par ticle size distr ibution analysis indicated that gener ated smoke...

  1. 40 CFR 63.4766 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...CONTINUED) National Emission Standards for Hazardous Air Pollutants: Surface Coating of Wood Building Products Compliance Requirements for the Emission Rate with Add-on Controls Option § 63.4766 How do I determine the...

  2. 40 CFR 63.4766 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...CONTINUED) National Emission Standards for Hazardous Air Pollutants: Surface Coating of Wood Building Products Compliance Requirements for the Emission Rate with Add-on Controls Option § 63.4766 How do I determine the...

  3. 40 CFR 63.4766 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...CONTINUED) National Emission Standards for Hazardous Air Pollutants: Surface Coating of Wood Building Products Compliance Requirements for the Emission Rate with Add-on Controls Option § 63.4766 How do I determine the...

  4. 40 CFR 63.3166 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Requirements for the Combined Electrodeposition Primer, Primer-Surfacer, Topcoat, Final Repair, Glass Bonding Primer, and Glass Bonding Adhesive Emission Limitations § 63.3166 How do I determine the add-on control device emission...

  5. 40 CFR 63.3166 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Requirements for the Combined Electrodeposition Primer, Primer-Surfacer, Topcoat, Final Repair, Glass Bonding Primer, and Glass Bonding Adhesive Emission Limitations § 63.3166 How do I determine the add-on control device emission...

  6. 40 CFR 63.3166 - How do I determine the add-on control device emission destruction or removal efficiency?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Requirements for the Combined Electrodeposition Primer, Primer-Surfacer, Topcoat, Final Repair, Glass Bonding Primer, and Glass Bonding Adhesive Emission Limitations § 63.3166 How do I determine the add-on control device emission...

  7. How phosphorus limitation can control climatic gas emission

    NASA Astrophysics Data System (ADS)

    Gypens, Nathalie; Borges, Alberto V.; Speeckaert, Gaelle; Ghyoot, Caroline

    2015-04-01

    Anthropogenic activities severely increased river nutrient [nitrogen (N) and phosphorus (P)] loads to European coastal areas. However, specific nutrient reduction policies implemented since the late 1990's have considerably reduced P loads, while N is maintained. In the Southern North Sea, the resulting N: P: Si imbalance (compared to phytoplankton requirements) stimulated the growth of Phaeocystis colonies modifying the functioning of the ecosystem and, therefore, the carbon cycle but also the biogenic sulphur cycle, Phaeocystis being a significant producer of DMSP (dimethylsulphide propionate), the precursor of dimethylsulfide (DMS). In this application, the mechanistic MIRO-BIOGAS model is used to investigate the effects of changing N and P loads on ecosystem structure and their impact on DMS and CO2 emissions. In particular, competition for P between phytoplankton groups (diatoms vs Phaeocystis colonies) but also between phytoplankton and bacteria is explored. The ability of autotroph and heterotroph organism to use dissolved organic phosphorus (DOP) as P nutrient source is also explored and its effect on climatic gas emission estimated. Simulations were done from 1950 to 2010 and different nutrient limiting conditions are analyzed.

  8. COAL CONVERSION CONTROL TECHNOLOGY. VOLUME II. GASEOUS EMISSIONS; SOLID WASTES

    EPA Science Inventory

    This volume is the product of an information-gathering effort relating to coal conversion process streams. Available and developing control technology has been evaluated in view of the requirements of present and proposed federal, state, regional, and international environmental ...

  9. Nitrogen oxides emission control options for coal-fired electric utility boilers.

    PubMed

    Srivastava, Ravi K; Hall, Robert E; Khan, Sikander; Culligan, Kevin; Lani, Bruce W

    2005-09-01

    Recent regulations have required reductions in emissions of nitrogen oxides (NOx) from electric utility boilers. To comply with these regulatory requirements, it is increasingly important to implement state-of-the-art NOx control technologies on coal-fired utility boilers. This paper reviews NOx control options for these boilers. It discusses the established commercial primary and secondary control technologies and examines what is being done to use them more effectively. Furthermore, the paper discusses recent developments in NOx controls. The popular primary control technologies in use in the United States are low-NOx burners and overfire air. Data reflect that average NOx reductions for specific primary controls have ranged from 35% to 63% from 1995 emissions levels. The secondary NOx control technologies applied on U.S. coal-fired utility boilers include reburning, selective noncatalytic reduction (SNCR), and selective catalytic reduction (SCR). Thirty-six U.S. coal-fired utility boilers have installed SNCR, and reported NOx reductions achieved at these applications ranged from 15% to 66%. Recently, SCR has been installed at >150 U.S. coal-fired utility boilers. Data on the performance of 20 SCR systems operating in the United States with low-NOx emissions reflect that in 2003, these units achieved NOx emission rates between 0.04 and 0.07 lb/10(6) Btu. PMID:16259432

  10. Nitrogen oxides emission control options for coal-fired electric utility boilers

    SciTech Connect

    Ravi K. Srivastava; Robert E. Hall; Sikander Khan; Kevin Culligan; Bruce W. Lani [U.S. Environmental Protection Agency, Research Triangle Park, NC (United States)

    2005-09-01

    Recent regulations have required reductions in emissions of nitrogen oxides (NOx) from electric utility boilers. To comply with these regulatory requirements, it is increasingly important to implement state-of-the-art NOx control technologies on coal-fired utility boilers. This paper reviews NOx control options for these boilers. It discusses the established commercial primary and secondary control technologies and examines what is being done to use them more effectively. Furthermore, the paper discusses recent developments in NOx controls. The popular primary control technologies in use in the United States are low-NOx burners and overfire air. Data reflect that average NOx reductions for specific primary controls have ranged from 35% to 63% from 1995 emissions levels. The secondary NOx control technologies applied on U.S. coal-fired utility boilers include reburning, selective noncatalytic reduction (SNCR), and selective catalytic reduction (SCR). Thirty-six U.S. coal-fired utility boilers have installed SNCR, and reported NOx reductions achieved at these applications ranged from 15% to 66%. Recently, SCR has been installed at 150 U.S. coal-fired utility boilers. Data on the performance of 20 SCR systems operating in the United States with low-NOx emissions reflect that in 2003, these units achieved NOx emission rates between 0.04 and 0.07 lb/106 Btu. 106 refs., 6 figs., 6 tabs.

  11. Diesel Exhaust Emissions Control for Light-Duty Vehicles

    SciTech Connect

    Mital, R.; Li, J.; Huang, S. C.; Stroia, B. J.; Yu, R. C. (Cummins, Inc.); Anderson, J.A. (Argonne National Laboratory); Howden, Kenneth C. (U.S. Department of Energy)

    2003-03-01

    The objective of this paper is to present the results of diesel exhaust aftertreatment testing and analysis done under the FreedomCAR program. Nitrogen Oxides (NOx) adsorber technology was selected based on a previous investigation of various NOx aftertreatment technologies including non-thermal plasma, NOx adsorber and active lean NOx. Particulate Matter (PM) emissions were addressed by developing a catalyzed particulate filter. After various iterations of the catalyst formulation, the aftertreatment components were integrated and optimized for a light duty vehicle application. This compact exhaust aftertreatment system is dual leg and consists of a sulfur trap, NOx adsorbers, and catalyzed particulate filters (CPF). During regeneration, supplementary ARCO ECD low-sulfur diesel fuel is injected upstream of the adsorber and CPF in the exhaust. Steady state and transient emission test results with and without the exhaust aftertreatment system (EAS) are presented. Results of soot filter regeneration by injecting low-sulfur diesel fuel and slip of unregulated emissions, such as NH3, are discussed. Effects of adsorber size and bypass strategy on NOx conversion efficiency and fuel economy penalty are also presented in this paper. The results indicate that if the supplementary fuel injection is optimized, NH3 slip is negligible. During the FTP cycle, injection of low sulfur diesel fuel can create temperature exotherms high enough to regenerate a loaded CPF. With the optimized NOx adsorber regeneration strategies the fuel injection penalty can be reduced by 40 to 50%. Results for various other issues like low temperature light off, reductant optimization, exhaust sulfur management, system integration and design trade-off, are also presented and discussed in this paper. (SAE Paper SAE-2003-01-0041 © 2003 SAE International. This paper is published on this website with permission from SAE International. As a user of this website, you are permitted to view this paper on-line, download this pdf file and print one copy of this paper at no cost for your use only. The downloaded pdf file and printout of this SAE paper may not be copied, distributed or forwarded to others or for the use of others.)

  12. Emissions and prevention/control techniques for automobile body shops in Ciudad Juarez, Mexico

    SciTech Connect

    Jeffery, J.D.; Sager, M.

    1999-08-01

    Emissions of Volatile Organic Compounds (VOC) from automobile body repair shops are believed to be significant and to contribute to ozone nonattainment in El Paso, Texas and to violations of ozone air quality standards in Ciudad Juarez, Mexico. The Direccion de Desarrollo Urbano Y Ecologia (DDUE), (the local agency in Ciudad Juarez, Mexico) requested CICA's assistance in determining emissions from and identifying appropriate pollution prevention and control techniques for automobile body repair shops in Ciudad Juarez.

  13. Total Diesel Emission Control Technology Using Ozone Injection and Plasma Desorption

    Microsoft Academic Search

    Masaaki Okubo; Naoki Arita; Tomoyuki Kuroki; Keiichiro Yoshida; Toshiaki Yamamoto

    2008-01-01

    An innovative total diesel emission control system for diesel particulate and NOx simultaneous reduction is proposed. In this system, the plasma reactor is located outside the emission exhaust pipe and activated\\u000a gas induced from ozone activated by the plasma is injected into the exhaust pipe. On the other hand, the NOx reduction is achieved using oxygen-poor nonthermal plasma desorption. The

  14. Evaluation of emissions and control technology for industrial stoker boilers. Final report, October 1977October 1980

    Microsoft Academic Search

    R. D. Giammar; R. H. Barnes; D. R. Hopper; P. R. Webb; A. E. Weller

    1981-01-01

    The report gives results of a three-phase program to evaluate emissions and control technology for industrial stoker boilers. In Phase I, emission characteristics were determined for a variety of coals fired in a 200-kW stoker boiler. It was observed that significant amounts of sulfur were retained in the lignite and western subbituminous coals. Fuel nitrogen conversion to NO was found

  15. Control of air pollution emissions from molybdenum roasting. Volume 2. Alternatives for control of weak sulfur dioxide emissions. Final report

    Microsoft Academic Search

    N. H. Masarky; R. D. Delleney; K. Schwitzgebel; T. P. Nelson; R. L. Glover

    1983-01-01

    This report covers the second phase of a three phase effort evaluating (1) characterization of particulate control of a molybdenum sulfide roasters, (2) assessment of sulfur dioxide abatement alternatives for nonferrous smelting and, in particular, for molybdenum roasting, and (3) pilot testing of the magnesia slurry process for sulfur dioxide control. It describes the results of a survey and evaluation

  16. Manipulating emission of CdSe\\/ZnS nanocrystals embedded in synthetic opals

    Microsoft Academic Search

    Paul Benalloul; Celine Vion; Charles Barthou; Catherine Schwob; Jean-Marc Frigerio; Agnes Maître; Alex Gruzintsev; Gennadi Emelchenko; Wladimir Masalov; Pham Thu Nga

    2009-01-01

    Photonic crystals (PCs) are the object of great interest due to the possibility, for appropriate PCs, to modify and control light propagation and even to influence the emission properties of an emitter, such as its emission diagram and its life time. One of the most common approaches to prepare 3D PCs takes advantage of the spontaneous self-organisation of spherical colloidal

  17. Advanced combustion techniques for controlling NO sub x emissions of high altitude cruise aircraft

    NASA Technical Reports Server (NTRS)

    Rudey, R. A.; Reck, G. M.

    1976-01-01

    An array of experiments designed to explore the potential of advanced combustion techniques for controlling the emissions of aircraft into the upper atmosphere was discussed. Of particular concern are the oxides of nitrogen (NOx) emissions into the stratosphere. The experiments utilize a wide variety of approaches varying from advanced combustor concepts to fundamental flame tube experiments. Results are presented which indicate that substantial reductions in cruise NOx emissions should be achievable in future aircraft engines. A major NASA program is described which focuses the many fundamental experiments into a planned evolution and demonstration of the prevaporized-premixed combustion technique in a full-scale engine.

  18. Nitrogen Oxides Emission Control Options for Coal-Fired Electric Utility Boilers

    Microsoft Academic Search

    Ravi K. Srivastava; Robert E. Hall; Sikander Khan; Kevin Culligan; Bruce W. Lani

    2005-01-01

    Recent regulations have required reductions in emissions of nitrogen oxides (NOx) from electric utility boilers. To comply with these regulatory requirements, it is increasingly important to implement state-of-the-art NOx control technologies on coal-fired utility boilers. This paper reviews NOx control options for these boilers. It discusses the established commercial primary and secondary control technologies and examines what is being done

  19. Regional differences in Chinese SO2 emission control efficiency and policy implications

    NASA Astrophysics Data System (ADS)

    Zhang, Q. Q.; Wang, Y.; Ma, Q.; Xie, Y.; He, K.

    2015-02-01

    SO2 emission control has been one of the most important air pollution policies in China since 2000. In this study, we assess regional differences in SO2 emission control efficiencies in China through the modeling analysis of four scenarios of SO2 emissions, all of which aim at reducing the national total SO2 emissions by 8% or 2.3 Tg below the 2010 emissions level, the target set by the current 12th FYP (2011-2015), but differ in the spatial implementation. The GEOS-Chem chemical transport model is used to evaluate the efficiency of each scenario on the basis of three impact metrics: surface sulfate concentration, population-weighted sulfate concentration (PWC), and sulfur export flux from China to the Western Pacific. The efficiency of SO2 control (?) is defined as the relative change of each impact metric to a 1% reduction of SO2 emissions from the 2010 baseline. The S1 scenario, which adopts a spatially uniform reduction of SO2 emissions in China, gives a ? of 0.71, 0.83, and 0.67 for sulfate concentration, PWC, and export flux, respectively. By comparison, the S2 scenario, which implements all the SO2 emissions reduction over North China (NC), is found most effective in reducing national-mean surface sulfate concentrations and sulfur export fluxes, with ? being 0.76 and 0.95 respectively. The S3 scenario of implementing all the SO2 emission reduction over South China (SC) has the highest ? in reducing PWC (? = 0.98) because SC has the highest correlation between population density and sulfate concentration. Reducing SO2 emissions over Southwest China (SWC) is found to be least efficient on the national scale, albeit within-region benefit. The difference in ? by scenario is attributable to regional differences in SO2 oxidation pathways and source-receptor relationships. Among the three regions examined here, NC shows the largest proportion of sulfate formation from gas phase oxidation, which is more sensitive to SO2 emission change than aqueous oxidation. In addition, NC makes the largest contribution to inter-regional transport of sulfur within China and to the transport fluxes to Western Pacific. The policy implication is that China needs to carefully design a regionally specific implementation plan of realizing its SO2 emissions reduction target in order to maximize the resulting air quality benefits not only for China but for the downwind regions, with emphasis on reducing emissions from NC.

  20. STANDARDS CONTROLLING AIR EMISSIONS FOR THE SOIL DESICCATION PILOT TEST

    SciTech Connect

    BENECKE MW

    2010-09-08

    This air emissions document supports implementation of the Treatability Test Plan for Soil Desiccation as outlined in the Deep Vadose Zone Treatability Test Plan for the Hanford Central Plateau (DOE/RL-2007-56). Treatability testing supports evaluation of remedial technologies for technetium-99 (Tc-99) contamination in the vadose zone at sites such as the BC Cribs and Trenches. Soil desiccation has been selected as the first technology for testing because it has been recommended as a promising technology in previous Hanford Site technology evaluations and because testing of soil desiccation will provide useful information to enhance evaluation of other technologies, in particular gas-phase remediation technologies. A soil desiccation pilot test (SDPT) will evaluate the desiccation process (e.g., how the targeted interval is dried) and the long-term performance for mitigation of contaminant transport. The SDPT will dry out a moist zone contaminated by Tc-99 and nitrate that has been detected at Well 299-E13-62 (Borehole C5923). This air emissions document applies to the activities to be completed to conduct the SDPT in the 200-BC-1 operable unit located in the 200 East Area of the Hanford Site. Well 299-E13-62 is planned to be used as an injection well. This well is located between and approximately equidistant from cribs 216-B-16, 216-B-17, 216-B-18. and 216-B-19. Nitrogen gas will be pumped at approximately 300 ft{sup 3}/min into the 299-EI3-62 injection well, located approximately 12 m (39 ft) away from extraction well 299-EI3-65. The soil gas extraction rate will be approximately 150 ft{sup 3}/min. The SDPT will be conducted continuously over a period of approximately six months. The purpose of the test is to evaluate soil desiccation as a potential remedy for protecting groundwater. A conceptual depiction is provided in Figure 1. The soil desiccation process will physically dry, or evaporate, some of the water from the moist zone of interest. As such, it is expected that Tc-99 and nitrate will remain with the water residual that is not removed, or remain as a salt bound to the soil particles. In addition, the SDPT will be conducted at lower extraction velocities to preclude pore water entrainment and thus, the extracted air effluent should be free of the contaminant residual present in the targeted moist zone. However, to conservatively bound the planned activity for potential radionuclide air emissions, it is assumed, hypothetically, that the Tc-99 does not remain in the zone of interest, but that it instead travels with the evaporated moisture to the extraction well and to the test equipment at the land surface. Thus, a release potential would exist from the planned point source (powered exhaust) for Tc-99 in the extracted moist air. In this hypothetical bounding case there would also be a potential for very minor fugitive emissions to occur due to nitrogen injection into the soil. The maximum value for Tc-99, measured in the contaminated moist zone, is used in calculating the release potential described in Section 2.3. The desiccation mechanism will be evaporation. Nitrate is neither a criteria pollutant nor a toxic air pollutant. It would remain nitrate as a salt adhered to sand and silt grains or as nitrate dissolved in the pore water. Nitrogen, an inert gas, will be injected into the ground during the test. Tracer gasses will also be injected near the beginning, middle, and the end of the test. The tracer gasses are sulfur hexafluoride, trichlorofluoromethane, and difluoromethane.