Sample records for controlling spontaneous emission

  1. Controlling spontaneous emission with plasmonic optical patch antennas

    E-print Network

    C. Belacel; B. Habert; F. Bigourdan; F. Marquier; J. -P. Hugonin; S. Michaelis de Vasconcellos; X. Lafosse; L. Coolen; C. Schwob; C. Javaux; B. Dubertret; J. -J. Greffet; P. Senellart; A. Maitre

    2012-09-28

    We experimentally demonstrate the control of the spontaneous emission rate and the radiation pattern of colloidal quantum dots deterministically positioned in a plasmonic patch antenna. The antenna consists of a thin gold microdisk 30 nm above a thick gold layer. The emitters are shown to radiate through the entire patch antenna in a highly directional and vertical radiation pattern. Strong acceleration of spontaneous emission is observed, depending of the antenna size. Considering the double dipole structure of the emitters, this corresponds to a Purcell factor up to 80 for dipoles perpendicular to the disk.

  2. 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

  3. 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.

  4. 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.

  5. High-precision atom localization via controllable spontaneous emission in a cycle-configuration atomic system.

    PubMed

    Ding, Chunling; Li, Jiahua; Yu, Rong; Hao, Xiangying; Wu, Ying

    2012-03-26

    A scheme for realizing two-dimensional (2D) atom localization is proposed based on controllable spontaneous emission in a coherently driven cycle-configuration atomic system. As the spatial-position-dependent atom-field interaction, the frequency of the spontaneously emitted photon carries the information about the position of the atom. Therefore, by detecting the emitted photon one could obtain the position information available, and then we demonstrate high-precision and high-resolution 2D atom localization induced by the quantum interference between the multiple spontaneous decay channels. Moreover, we can achieve 100% probability of finding the atom at an expected position by choosing appropriate system parameters under certain conditions. PMID:22453461

  6. Controlling the spontaneous emission rate of monolayer MoS[subscript 2] in a photonic crystal nanocavity

    E-print Network

    Gan, Xuetao

    We report on controlling the spontaneous emission (SE) rate of a molybdenum disulfide (MoS[subscript 2]) monolayer coupled with a planar photonic crystal (PPC) nanocavity. Spatially resolved photoluminescence (PL) mapping ...

  7. Controlling the spontaneous emission rate of monolayer MoS2 in a photonic crystal nanocavity

    PubMed Central

    Gan, Xuetao; Gao, Yuanda; Fai Mak, Kin; Yao, Xinwen; Shiue, Ren-Jye; van der Zande, Arend; Trusheim, Matthew E.; Hatami, Fariba; Heinz, Tony F.; Hone, James; Englund, Dirk

    2013-01-01

    We report on controlling the spontaneous emission (SE) rate of a molybdenum disulfide (MoS2) monolayer coupled with a planar photonic crystal (PPC) nanocavity. Spatially resolved photoluminescence (PL) mapping shows strong variations of emission when the MoS2 monolayer is on the PPC cavity, on the PPC lattice, on the air gap, and on the unpatterned gallium phosphide substrate. Polarization dependences of the cavity-coupled MoS2 emission show a more than 5 times stronger extracted PL intensity than the un-coupled emission, which indicates an underlying cavity mode Purcell enhancement of the MoS2 SE rate exceeding a factor of 70. PMID:24273329

  8. 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.

  9. Control of the entanglement between triple quantum dot molecule and its spontaneous emission fields via quantum entropy

    NASA Astrophysics Data System (ADS)

    Sahrai, M.; Arzhang, B.; Taherkhani, D.; Boroojerdi, V. Tahmoorian Askari

    2015-03-01

    The time evolution of the quantum entropy in a coherently driven triple quantum dot molecule is investigated. The entanglement of the quantum dot molecule and its spontaneous emission field is coherently controlled by the gate voltage and the rate of an incoherent pump field. The degree of entanglement between a triple quantum dot molecule and its spontaneous emission fields is decreased by increasing the tunneling parameter.

  10. 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.

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

    E-print Network

    Alexey Kalachev; Stefan Kroll

    2006-06-19

    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 life-time. Specifically the applicability for storing time-bin qubits, which are used in quantum cryptography is analyzed.

  12. 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.

  13. Quenching of spontaneous emission through interference of incoherent pump processes

    E-print Network

    Kapale, KT; Scully, Marlan O.; Zhu, S. Y.; Zubairy, M. Suhail

    2003-01-01

    controllable handle in manipulating the spontaneous emission to such an extent that, under certain conditions, complete quenching of spontaneous emission is possible. We also show that even the interference between the decay channels, which is considered a key...

  14. Optical antenna enhanced spontaneous emission.

    PubMed

    Eggleston, Michael S; Messer, Kevin; Zhang, Liming; Yablonovitch, Eli; Wu, Ming C

    2015-02-10

    Atoms and molecules are too small to act as efficient antennas for their own emission wavelengths. By providing an external optical antenna, the balance can be shifted; spontaneous emission could become faster than stimulated emission, which is handicapped by practically achievable pump intensities. In our experiments, InGaAsP nanorods emitting at ?200 THz optical frequency show a spontaneous emission intensity enhancement of 35× corresponding to a spontaneous emission rate speedup ?115×, for antenna gap spacing, d = 40 nm. Classical antenna theory predicts ?2,500× spontaneous emission speedup at d ? 10 nm, proportional to 1/d(2). Unfortunately, at d < 10 nm, antenna efficiency drops below 50%, owing to optical spreading resistance, exacerbated by the anomalous skin effect (electron surface collisions). Quantum dipole oscillations in the emitter excited state produce an optical ac equivalent circuit current, Io = q?|xo|/d, feeding the antenna-enhanced spontaneous emission, where q|xo| is the dipole matrix element. Despite the quantum-mechanical origin of the drive current, antenna theory makes no reference to the Purcell effect nor to local density of states models. Moreover, plasmonic effects are minor at 200 THz, producing only a small shift of antenna resonance frequency. PMID:25624503

  15. Optical antenna enhanced spontaneous emission

    PubMed Central

    Eggleston, Michael S.; Messer, Kevin; Zhang, Liming; Yablonovitch, Eli; Wu, Ming C.

    2015-01-01

    Atoms and molecules are too small to act as efficient antennas for their own emission wavelengths. By providing an external optical antenna, the balance can be shifted; spontaneous emission could become faster than stimulated emission, which is handicapped by practically achievable pump intensities. In our experiments, InGaAsP nanorods emitting at ?200 THz optical frequency show a spontaneous emission intensity enhancement of 35× corresponding to a spontaneous emission rate speedup ?115×, for antenna gap spacing, d = 40 nm. Classical antenna theory predicts ?2,500× spontaneous emission speedup at d ? 10 nm, proportional to 1/d2. Unfortunately, at d < 10 nm, antenna efficiency drops below 50%, owing to optical spreading resistance, exacerbated by the anomalous skin effect (electron surface collisions). Quantum dipole oscillations in the emitter excited state produce an optical ac equivalent circuit current, Io = q?|xo|/d, feeding the antenna-enhanced spontaneous emission, where q|xo| is the dipole matrix element. Despite the quantum-mechanical origin of the drive current, antenna theory makes no reference to the Purcell effect nor to local density of states models. Moreover, plasmonic effects are minor at 200 THz, producing only a small shift of antenna resonance frequency. PMID:25624503

  16. Cooling molecular vibrations with shaped laser pulses: optimal control theory exploiting the timescale separation between coherent excitation and spontaneous emission

    NASA Astrophysics Data System (ADS)

    Reich, Daniel M.; Koch, Christiane P.

    2013-12-01

    Laser cooling of molecules employing broadband optical pumping involves a timescale separation between laser excitation and spontaneous emission. Here, we optimize the optical pumping step using shaped laser pulses. We derive two optimization functionals to drive population into those excited state levels that have the largest spontaneous emission rates to the target state. We show that, when using optimal control, laser cooling of molecules works even if the Franck-Condon map governing the transitions is preferential to heating rather than cooling. Our optimization functional is also applicable to the laser cooling of other degrees of freedom provided the cooling cycle consists of coherent excitation and dissipative de-excitation steps whose timescales are separated.

  17. Quenching of spontaneous emission through interference of incoherent pump processes

    SciTech Connect

    Kapale, Kishore T. [Institute for Quantum Studies and Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States); Scully, Marlan O. [Institute for Quantum Studies and Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States); Max-Planck-Institut fuer Quantenoptik, D-85748 Garching (Germany); Zhu Shiyao [Institute for Quantum Studies and Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States); Department of Physics, Hong Kong Baptist University, Hong Kong (China); Zubairy, M. Suhail [Institute for Quantum Studies and Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States); Department of Electronics, Quaid-i-Azam University, Islamabad (Pakistan)

    2003-02-01

    We investigate the steady-state spontaneous emission of a V-type three-level atom, with the coherence between the two upper levels modified and controlled via incoherent pumping to a fourth auxiliary level. The external pumping gives us an easily controllable handle in manipulating the spontaneous emission to such an extent that, under certain conditions, complete quenching of spontaneous emission is possible. We also show that even the interference between the decay channels, which is considered a key requirement in spontaneous emission quenching through quantum interference, is not essential to achieve near 100% trapping and almost complete suppression of spontaneous emission. Thus we provide a scheme for spontaneous emission quenching which can be easily realized experimentally.

  18. Spontaneous Photon Emission in Cavities

    E-print Network

    Gernot Alber; Nils Trautmann

    2014-12-04

    We investigate spontaneous photon emission processes of two-level atoms in parabolic and ellipsoidal cavities thereby taking into account the full multimode scenario. In particular, we calculate the excitation probabilities of the atoms and the energy density of the resulting few-photon electromagnetic radiation field by using semiclassical methods for the description of the multimode scenario. Based on this approach photon path representations are developed for relevant transition probability amplitudes which are valid in the optical frequency regime where the dipole and the rotating-wave approximations apply. Comparisons with numerical results demonstrate the quality of these semiclassical results even in cases in which the wave length of a spontaneously emitted photon becomes comparable or even larger than characteristic length scales of the cavity. This is the dynamical regime in which diffraction effects become important so that geometric optical considerations are typically not applicable.

  19. 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

  20. Blue shift of spontaneous emission in hyperbolic metamaterial

    NASA Astrophysics Data System (ADS)

    Gu, Lei; Tumkur, T. U.; Zhu, G.; Noginov, M. A.

    2014-06-01

    Spontaneous emission is one of the most fundamental quantum phenomena in optics. Following the seminal work of Purcell and in agreement with the Fermi's Golden Rule, its rate can be controlled with the photonic density of states (PDOS). In recent years, this effect has been demonstrated in metamaterials with hyperbolic dispersion - highly anisotropic composite materials, which have a broad-band singularity of the density of photonic states. At this time, we show that hyperbolic metamaterials can control spontaneous emission spectra as well. Experimentally, DCM laser dye has been embedded into lamellar metal/dielectric metamaterial. The observed 18 nm blue shift of emission is explained by strong dispersion of the density of photonic states. On the other hand, practically no spectral shift has been observed in the excitation spectra of the same dye. This suggests that the effect of PDOS on spontaneous emission is very different from its effect on excitation and absorption.

  1. Blue shift of spontaneous emission in hyperbolic metamaterial

    PubMed Central

    Gu, Lei; Tumkur, T. U.; Zhu, G.; Noginov, M. A.

    2014-01-01

    Spontaneous emission is one of the most fundamental quantum phenomena in optics. Following the seminal work of Purcell and in agreement with the Fermi's Golden Rule, its rate can be controlled with the photonic density of states (PDOS). In recent years, this effect has been demonstrated in metamaterials with hyperbolic dispersion – highly anisotropic composite materials, which have a broad-band singularity of the density of photonic states. At this time, we show that hyperbolic metamaterials can control spontaneous emission spectra as well. Experimentally, DCM laser dye has been embedded into lamellar metal/dielectric metamaterial. The observed 18?nm blue shift of emission is explained by strong dispersion of the density of photonic states. On the other hand, practically no spectral shift has been observed in the excitation spectra of the same dye. This suggests that the effect of PDOS on spontaneous emission is very different from its effect on excitation and absorption. PMID:24957679

  2. Spontaneous emission through heavy photon bands

    NASA Astrophysics Data System (ADS)

    Yannopapas, Vassilios

    2004-07-01

    We examine the spontaneous emission spectrum of a Lgr-type three-level atom embedded in a coupled-resonator optical waveguide. Owing to the high degree of confinement of light within the resonators, the waveguide modes can be obtained in the framework of an electromagnetic tight-binding theory. The corresponding density of modes exhibits singularities at the band edges leading to interesting features in the spontaneous emission spectrum such as dark lines and narrow emission peaks. The position and the shape of these features depend strongly on the geometry and refractive index of the waveguide.

  3. 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.

  4. Competition between coherent emission and broadband spontaneous emission in the quantum free electron laser

    SciTech Connect

    Robb, G. R. M. [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG, Scotland (United Kingdom); Bonifacio, R. [INFN-LNF, Via E. Fermi, 40-00044 Frascati, Rome (Italy) and Departamento de Fisica, Universidade Federal da Paraiba, Joao Pessoa (Brazil)

    2013-03-15

    We extend previous analyses of spontaneous emission in a quantum free electron laser (QFEL) and competition between spontaneous and coherent QFEL emission to include a broad distribution of photon frequencies and momenta appropriate for spontaneous undulator radiation. We show that although the predictions of monochromatic and broadband models predict different electron momentum distributions for the quantum regime due to spontaneous emission alone after many photon emissions, the inclusion of broadband spontaneous emission has a negligible effect on the competition between spontaneous and coherent emission in the QFEL. Numerical results from both models are well described by the same condition for the threshold/critical value of spontaneous emission rate.

  5. Spontaneous and stimulated emission from quasifree electrons

    NASA Astrophysics Data System (ADS)

    Friedman, A.; Gover, A.; Kurizki, G.; Ruschin, S.; Yariv, A.

    1988-04-01

    This article presents a unified formulation and review of an extensive class of radiation effects and devices based on free or quasifree electrons. The effects and devices reviewed include slow-wave radiators [such as ?erenkov, Smith-Purcell, and TWT (traveling-wave tube) effects and devices], periodic bremsstrahlung radiators [such as undulator radiation, magnetic bremsstrahlung FEL's (free-electron lasers), and coherent bremsstrahlung in the crystal lattice], and transverse-binding radiators [such as the CRM (cyclotron resonance maser) and channeling radiation]. Starting from a general quantum-electrodynamic model, both quantum and classical effects and operating regimes of these radiation devices are described. The article provides a unified physical description of the interaction kinematics, and presents equations for the characterization of spontaneous and stimulated radiative emission in these various effects and devices. Universal relations between the spontaneous and stimulated emission parameters are revealed and shown to be related (in the quantum limit) to Einstein relations for atomic radiators and (in the classical limit) to the relations derived by Madey for magnetic bremsstrahlung FEL for on-axis radiative emission. Examples for the application of the formulation are given, estimating the feasibility of channeling radiation x-ray laser and optical regime Smith-Purcell FEL, and deriving the gain equations of magnetic bremsstrahlung FEL and CRM for arbitrary electron propagation direction, structure (wiggler) axis, and radiative emission angle.

  6. Cooperative spontaneous emission of three identical atoms

    E-print Network

    Wei Feng; Yong Li; Shi-Yao Zhu

    2013-02-06

    We study the influence of the distribution of atoms on the cooperative spontaneous emission by a simple model of three identical atoms. The effects of counter rotating terms are included by a unitary transformation method. By discussing two special cases that the three atoms are arranged as an equilateral triangle and in a straight line, we find that the superradiance of the coherent system largely dependent on the homogeneity of the atoms' distribution. If the atoms distribute symmetrically, the superradiant emission will be enhanced. Next, we calculate the emission spectra of three identical atoms under the single-photon state. We find that the distribution of atoms also has a great impact on the lamb shift and the spectrum. If three atoms are placed into an equilateral triangle and the same dipole moment is perpendicular to the plane of the three atoms, the spectrum will degenerate into two peaks from the three peaks for general case.

  7. 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.

  8. Spontaneous emission from a tunneling atom

    NASA Astrophysics Data System (ADS)

    Braun, Daniel; Martin, John

    2008-03-01

    We study the tunneling of a two-level atom in a double well potential in while the atom couples either to a single electromagnetic field mode of a cavity to the full continuum of electromagnetic modes in three dimensions. Both studies are within the Lamb-Dicke regime concerning transitions to higher vibrational states, but beyond the Lamb-Dicke regime concerning the tunneling split groundstate. The first case leads to an extended Jaynes-Cummings model which can be solved exactly. We show that the coupling between internal and external degrees of freedom of the atom induced by the cavity mode can dramatically change the tunneling behavior. In general the tunneling process becomes quasiperiodic. If the cavity is fed with a coherent state, a collapse and revival of the tunneling can occur. Accessing the internal degrees of freedom of the atom with a laser allows to coherently manipulate the atom position, and in particular to prepare the atom in one of the two wells. In the second case, the tunneling process may decohere, depending on the wavelength corresponding to the internal transition and on the spontaneous emission rate. Interference fringes appear in the emitted light from a tunneling atom, or an atom in a stationary coherent superposition of its center--of--mass motion, if the wavelength is comparable to the well separation and if the external state of the atom is post-selected.[1] J. Martin and D. Braun, arXiv:0704.0763 and arXiv:0707.4158.

  9. The Effect of Contralateral Acoustic Stimulation on Spontaneous Otoacoustic Emissions

    PubMed Central

    Dhar, Sumitrajit

    2009-01-01

    Evoked otoacoustic emissions are often used to study the medial olivocochlear (MOC) efferents in humans. There has been concern that the emission-evoking stimulus may itself elicit efferent activity and alter the evoked otoacoustic emission. Spontaneous otoacoustic emissions (SOAEs) are hence advantageous as no external stimulation is necessary to record the response in the test ear. Contralateral acoustic stimulation (CAS) has been shown to suppress SOAE level and elevate SOAE frequency, but the time course of these effects is largely unknown. By utilizing the Choi–Williams distribution, here we report a gradual adaptation during the presence of CAS and an overshoot following CAS offset in both SOAE magnitude and frequency from six normal-hearing female human subjects. Furthermore, we have quantified the time constants of both magnitude and frequency shifts at the onset, presence, and offset of four levels of CAS. Most studies using contralateral elicitors do not stringently control the middle-ear muscle (MEM) reflex, leaving the results difficult to interpret. In addition to clinically available measures of the MEM reflex, we have incorporated a sensitive laboratory technique to monitor the MEM reflex in our subjects, allowing us to interpret the results with greater confidence. PMID:19798532

  10. Spontaneous emotion regulation and attentional control.

    PubMed

    Morillas-Romero, Alfonso; Tortella-Feliu, Miquel; Balle, Maria; Bornas, Xavier

    2015-04-01

    The current study aimed to explore whether self-reported attentional control (AC) and the attentional network functioning would predict spontaneous emotion downregulation after emotional induction. A total of 117 healthy volunteers were asked to continuously rate their discomfort while looking at affective pictures, as well as for a period of time after exposure. After controlling for trait anxiety, higher self-reported AC significantly predicted a greater spontaneous emotional downregulation after exposure to aversive pictures. Both higher self-reported AC and lower executive control network functioning (i.e., greater interference) predicted a faster spontaneous emotional downregulation after exposure to affectively neutral pictures. Results are discussed focusing on the relationship between AC and emotion regulation difficulties. (PsycINFO Database Record PMID:25151518

  11. 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

  12. Large spontaneous emission rate enhancement in grating coupled hyperbolic metamaterials

    PubMed Central

    Sreekanth, Kandammathe Valiyaveedu; Krishna, Koduru Hari; De Luca, Antonio; Strangi, Giuseppe

    2014-01-01

    Hyperbolic metamaterial (HMM), a sub-wavelength periodic artificial structure with hyperbolic dispersion, can enhance the spontaneous emission of quantum emitters. Here, we demonstrate the large spontaneous emission rate enhancement of an organic dye placed in a grating coupled hyperbolic metamaterial (GCHMM). A two-dimensional (2D) silver diffraction grating coupled with an Ag/Al2O3 HMM shows 18-fold spontaneous emission decay rate enhancement of dye molecules with respect to the same HMM without grating. The experimental results are compared with analytical models and numerical simulations, which confirm that the observed enhancement of GCHMM is due to the outcoupling of non-radiative plasmonic modes as well as strong plasmon-exciton coupling in HMM via diffracting grating. PMID:25209102

  13. Single photon generation by corporative spontaneous emission of atomic ensembles

    NASA Astrophysics Data System (ADS)

    Hossein-Nejad, Hoda; Stock, Rene; James, Daniel F. V.

    2008-05-01

    The ability to generate single photons on demand is of key importance in a variety of quantum optical applications including quantum key distribution and quantum computation. Recent advances in ion trap technology allow complete control over all degrees of freedom of the trapped ions which in turn permits the creation of large entangled states with long coherence times. In this work, we investigate the feasibility of this technology for deterministic generation of single photons by harnessing the corporative spontaneous emission of the ions. We consider different geometric arrangements of entangled ions and aim to reduce the allowed decay modes into a narrow solid angle such that the emitted photon can be coupled to an optical fiber. For lattice spacings of the order of a wavelength or so, corporative radiative effects must be accounted for. Rather counterintuitively perhaps, superradiance tends to be undesirable since it can drastically alter the lifetime of different decay channels. The ion arrangement must therefore be optimized to ensure not only emission into a narrow solid angle but also that all the decay modes have approximately the same lifetime.

  14. 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.

  15. Random Number Generation Using Amplified Spontaneous Emission in a Fiber Amplifier

    E-print Network

    Anlage, Steven

    Random Number Generation Using Amplified Spontaneous Emission in a Fiber Amplifier Julia C. Salevan · Photon counting · Amplified spontaneous emission #12;System Er:Yb EDFA Bandpass Filter (FBG) ( 0 = 1552

  16. A hybrid nanoantenna for highly enhanced directional spontaneous emission

    SciTech Connect

    Chou, R. Yuanying; Lu, Guowei, E-mail: guowei.lu@pku.edu.cn; Shen, Hongming; He, Yingbo; Cheng, Yuqing [State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871 (China); Perriat, Pascal [MATEIS, UMR 5510 CNRS, INSA-Lyon, Université de Lyon, Villeurbanne Cedex 69621 (France); Martini, Matteo; Tillement, Olivier [ILM, UMR 5306 CNRS, Université de Lyon, Villeurbanne Cedex 69622 (France); Gong, Qihuang [State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter, Beijing 100871 (China)

    2014-06-28

    Spontaneous emission modulated by a hybrid plasmonic nanoantenna has been investigated by employing finite-difference time-domain method. The hybrid nanoantenna configurations constituted by a gap hot-spot and of a plasmonic corrugated grating and a metal reflector sandwiching a SiO{sub 2} thin layer which appears promising for high spontaneous emission enhancement devices. Simulation assays show that the coupling between the gap-antenna and plasmonic corrugations reaches an ultra-high near-field enhancement factor in the excitation process. Moreover, concerning the emission process, the corrugations concentrate the far-field radiated power within a tiny angular volume, offering unprecedented collection efficiency. In the past decades, many kinds of optical antennas have been proposed and optimized to enhance single molecule detection. However, the excitation enhancement effect for single individual or dimmer plasmonic nanostructure is limited due to intrinsic nonradiative decay of the nanoparticle plasmon and quantum tunneling effect. The proposed hybrid configuration overwhelms the enhancement limit of single individual plasmonic structure. The findings provide an insight into spontaneous emission high enhancement through integrating the functions of different metallic nanostructures.

  17. hal-00136128,version1-12Mar2007 Spontaneous emission of graviton by a quantum

    E-print Network

    Paris-Sud XI, Université de

    hal-00136128,version1-12Mar2007 Spontaneous emission of graviton by a quantum bouncer G Pignol, K, Grenoble, France Abstract. Spontaneous emission of graviton rates for the quantum bouncer states of this problem #12;Spontaneous emission of graviton by a quantum bouncer 2 are: z0 = 2 2m2g 1/3 = 5.87 µm (2) E0

  18. 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.

  19. Dual-channel spontaneous emission of quantum dots in magnetic metamaterials

    NASA Astrophysics Data System (ADS)

    Decker, Manuel; Staude, Isabelle; Shishkin, Ivan I.; Samusev, Kirill B.; Parkinson, Patrick; Sreenivasan, Varun K. A.; Minovich, Alexander; Miroshnichenko, Andrey E.; Zvyagin, Andrei; Jagadish, Chennupati; Neshev, Dragomir N.; Kivshar, Yuri S.

    2013-12-01

    Metamaterials, artificial electromagnetic media realized by subwavelength nano-structuring, have become a paradigm for engineering electromagnetic space, allowing for independent control of both electric and magnetic responses of the material. Whereas most metamaterials studied so far are limited to passive structures, the need for active metamaterials is rapidly growing. However, the fundamental question on how the energy of emitters is distributed between both (electric and magnetic) interaction channels of the metamaterial still remains open. Here we study simultaneous spontaneous emission of quantum dots into both of these channels and define the control parameters for tailoring the quantum-dot coupling to metamaterials. By superimposing two orthogonal modes of equal strength at the wavelength of quantum-dot photoluminescence, we demonstrate a sharp difference in their interaction with the magnetic and electric metamaterial modes. Our observations reveal the importance of mode engineering for spontaneous emission control in metamaterials, paving a way towards loss-compensated metamaterials and metamaterial nanolasers.

  20. Quantum theory of spontaneous and stimulated emission of surface plasmons

    SciTech Connect

    Archambault, Alexandre; Marquier, Francois; Greffet, Jean-Jacques; Arnold, Christophe [Laboratoire Charles Fabry, Institut d Optique, CNRS-Univ Paris-Sud, Campus Polytechnique, RD128, 91127 Palaiseau Cedex (France); Laboratoire de Photonique et de Nanostructures, CNRS, Route de Nozay, 91460 Marcoussis (France)

    2010-07-15

    We introduce a quantization scheme that can be applied to surface waves propagating along a plane interface. An important result is the derivation of the energy of the surface wave for dispersive nonlossy media without invoking any specific model for the dielectric constant. Working in Coulomb's gauge, we use a modal representation of the fields. Each mode can be associated with a quantum harmonic oscillator. We have applied the formalism to derive quantum mechanically the spontaneous emission rate of surface plasmon by a two-level system. The result is in very good agreement with Green's tensor approach in the nonlossy case. Green's approach allows also to account for losses, so that the limitations of a quantum approach of surface plasmons are clearly defined. Finally, the issue of stimulated versus spontaneous emission has been addressed. Because of the increasing density of states near the asymptote of the dispersion relation, it is quantitatively shown that the stimulated emission probability is too small to obtain gain in this frequency region.

  1. Amplified spontaneous emission in the spiropyran-biopolymer based system

    NASA Astrophysics Data System (ADS)

    Mysliwiec, Jaroslaw; Sznitko, Lech; Bartkiewicz, Stanislaw; Miniewicz, Andrzej; Essaidi, Zacaria; Kajzar, Francois; Sahraoui, Bouchta

    2009-06-01

    Amplified spontaneous emission (ASE) phenomenon in the 6-nitro-1',3',3'-trimethylspiro[2H-1-benzopyran-2,2'-indolin] organic dye dispersed in a solid matrix has been observed. The biopolymer system deoxyribonucleic acid blended with cationic surfactant molecule cetyltrimethyl-ammonium chloride served as a matrix. ASE appeared under sample excitation by UV light pulses (? =355 nm) coming from nanosecond or picosecond neodymium doped yttrium aluminum garnet lasers and has been reinforced with green (? =532 nm) light excitation followed UV light pulse. The ASE characteristics in function of different excitation pulse energies as well as signal gain were measured.

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

    E-print Network

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

    2005-01-01

    to measure quantum states and re- construct multimode entangled states in a cavity. In a recent paper, Xiong, Scully, and Zubairy #3;15#4; have proposed a scheme for an entanglement amplifier based on a two-mode correlated spontaneous emission laser.... Huang, S.-Y. Zhu, and M. S. Zubairy, Phys. Rev. A 53 1027 #1;1996#2;. #3;14#4; M. Ahmad, S. Qamar, and M. S. Zubairy, Phys. Rev. A 67, 043815 #1;2003#2;; 64, 023811 #1;2001#2;. #3;15#4; H. Xiong, M. O. Scully, and M. S. Zubairy, Phys. Rev. Lett. 94...

  3. 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

  4. Non-exponential spontaneous emission dynamics for emitters in a time-dependent optical cavity.

    PubMed

    Thyrrestrup, Henri; Hartsuiker, Alex; Gérard, Jean-Michel; Vos, Willem L

    2013-10-01

    We have theoretically studied the effect of deterministic temporal control of spontaneous emission in a dynamic optical microcavity. We propose a new paradigm in light emission: we envision an ensemble of two-level emitters in an environment where the local density of optical states is modified on a time scale shorter than the decay time. A rate equation model is developed for the excited state population of two-level emitters in a time-dependent environment in the weak coupling regime in quantum electrodynamics. As a realistic experimental system, we consider emitters in a semiconductor microcavity that is switched by free-carrier excitation. We demonstrate that a short temporal increase of the radiative decay rate depletes the excited state and drastically increases the emission intensity during the switch time. The resulting time-dependent spontaneous emission shows a distribution of photon arrival times that strongly deviates from the usual exponential decay: A deterministic burst of photons is spontaneously emitted during the switch event. PMID:24104228

  5. Time-reversal symmetrization of spontaneous emission for quantum state transfer

    NASA Astrophysics Data System (ADS)

    Srinivasan, Srikanth J.; Sundaresan, Neereja M.; Sadri, Darius; Liu, Yanbing; Gambetta, Jay M.; Yu, Terri; Girvin, S. M.; Houck, Andrew A.

    2014-03-01

    We demonstrate the ability to control spontaneous emission from a superconducting qubit coupled to a cavity. The time domain profile of the emitted photon is shaped into a symmetric truncated exponential. The experiment is enabled by a qubit coupled to a cavity, with a coupling strength that can be tuned in tens of nanoseconds while maintaining a constant dressed state emission frequency. Symmetrization of the photonic wave packet will enable use of photons as flying qubits for transferring the quantum state between atoms in distant cavities.

  6. Guided Mode for Enhanced Spontaneous Emission Using Finite Thickness Photonic Crystal Waveguides

    NASA Astrophysics Data System (ADS)

    Amorntep, W.; Wanchai, P.

    Guided mode for enhanced spontaneous emission of light is essential to quantum optics in design and development of high efficiency optical devices which are useful to security optical communication system. Thus, we performed to develop an efficient single photon source by controlling inhibited or enhanced spontaneous emission of the photon using silicon-based honeycomb lattice patterned finite thickness photonic crystal waveguide. A quantum dot embedded in planar photonic crystal membrane waveguide is the light source. The honeycomb lattice of circular air holes on silicon plate is simulated to obtain completely photonic band gaps, guided mode resonant frequency, quality factor, and effective volume mode. This significant property shows the potential applied guide modes of photonic crystal waveguide for controlling enhanced spontaneous emission. Significantly, this work is oriented to produce the novel single photon sources which can emit one photon at a time for the quantum optical security network with single photon state. In addition to the honeycomb lattice can easily be made on a Si on insulator (SOI) wafer.

  7. Controlling Cotton Gin Emissions

    Microsoft Academic Search

    William J. Roddy

    1978-01-01

    Since cotton today is machine picked, the mere process of ginning creates a significant amount of trash and dust. A large cotton gin in Fresno operating at 23 bales per hour uses two rotating filters to control this material. Total emissions from the facility are in the order of 50 pounds per hour, or about one-half the emissions from a

  8. Sex and Ear Differences in Spontaneous and Click-Evoked Otoacoustic Emissions in Young Adults

    ERIC Educational Resources Information Center

    Snihur, Adrian W. K.; Hampson, Elizabeth

    2011-01-01

    Effects of sex and handedness on the production of spontaneous and click-evoked otoacoustic emissions (OAEs) were explored in a non-hearing impaired population (ages 17-25 years). A sex difference in OAEs, either produced spontaneously (spontaneous OAEs or SOAEs) or in response to auditory stimuli (click-evoked OAEs or CEOAEs) has been reported in…

  9. 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.

  10. Fast physical random number generator using amplified spontaneous emission.

    PubMed

    Williams, Caitlin R S; Salevan, Julia C; Li, Xiaowen; Roy, Rajarshi; Murphy, Thomas E

    2010-11-01

    We report a 12.5 Gb/s physical random number generator (RNG) that uses high-speed threshold detection of the spectrally-sliced incoherent light produced by a fiber amplifier. The system generates a large-amplitude, easily measured, fluctuating signal with bandwidth that is constrained only by the optical filter and electrical detector used. The underlying physical process (spontaneous emission) is inherently quantum mechanical in origin, and therefore cannot be described deterministically. Unlike competing optical RNG approaches that require photon counting electronics, chaotic laser cavities, or state-of-the-art analog-to-digital converters, the system employs only commonly available telecommunications-grade fiber optic components and can be scaled to higher speeds or multiplexed into parallel channels. The quality of the resulting random bitstream is verified using industry-standard statistical tests. PMID:21164703

  11. Frequency clustering in spontaneous otoacoustic emissions from a lizard's ear.

    PubMed

    Vilfan, Andrej; Duke, Thomas

    2008-11-15

    Spontaneous otoacoustic emissions (SOAEs) are indicators of an active process in the inner ear that enhances the sensitivity and frequency selectivity of hearing. They are particularly regular and robust in certain lizards, so these animals are good model organisms for studying how SOAEs are generated. We show that the published properties of SOAEs in the bobtail lizard are wholly consistent with a mathematical model in which active oscillators, with exponentially varying characteristic frequencies, are coupled together in a chain by visco-elastic elements. Physically, each oscillator corresponds to a small group of hair cells, covered by a tectorial sallet, so our theoretical analysis directly links SOAEs to the micromechanics of active hair bundles. PMID:18689448

  12. Random Number Generation Using Amplified Spontaneous Emission in a Fiber Amplifier

    E-print Network

    Anlage, Steven

    . Results Yb/Er FA: Ytterbium/Erbium Fiber Amplifier BPF: Band Pass Filter EDFA: Erbium Doped FiberRandom Number Generation Using Amplified Spontaneous Emission in a Fiber Amplifier Julia C. Salevan spontaneous emission in a fiber amplifier as our random source. System Conclusions and Future Work Statistical

  13. 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

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

    NASA Astrophysics Data System (ADS)

    Wang, Yang-Yang; Zhang, Tong

    2014-09-01

    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.

  15. 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

  16. 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.

  17. High-frequency spontaneous emission of an electron beam injected into the ionospheric plasma

    Microsoft Academic Search

    J. Lavergnat; R. Pellat

    1979-01-01

    This paper gives a detailed quantitative analysis of the high-frequency spontaneous wave emissions produced by an electron beam injected into the ionospheric plasma. A general discussion about individual-collective and incoherent-coherent characteristics of the emissions is given. Then attention is focused on the spontaneous coherent emission in three different modes: plasma waves, Bernstein modes, and electromagnetic whistler mode. Comparisons with experimental

  18. Automotive Emission Control.

    ERIC Educational Resources Information Center

    Lee, Billy D.; And Others

    This publication contains instructional materials for both teachers and students for a course in automotive emission control. Instructional materials in this publication are written in terms of student performance using measurable objectives. The course includes 16 units. Each instructional unit includes some or all of the basic components of a…

  19. 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…

  20. 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.

  1. 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

  2. Emission of alpha particles during the spontaneous fission of {sup 244}Pu

    SciTech Connect

    Verboven, M.; Jacobs, E.; De Frenne, D.; Thierens, H.; D`hondt, P. [Nuclear Physics Laboratory, Proeftuinstraat 86, B-9000 Gent (Belgium)] [Nuclear Physics Laboratory, Proeftuinstraat 86, B-9000 Gent (Belgium)

    1994-03-01

    We have measured the light charged particle (LCP) emission probabililty for the spontaneous fission of {sup 244}Pu. For the LCP emission to binary fission probability ratio a value of (2.96{plus_minus}0.31){times}10{sup {minus}3} was found. This result is in agreement with the previously observed trends concerning the LCP emission probability.

  3. Periodontal disease and spontaneous preterm birth: a case control study

    Microsoft Academic Search

    Stephen Wood; Albert Frydman; Stephen Cox; Rollin Brant; Sheilia Needoba; Barry Eley; Reg Sauve

    2006-01-01

    BACKGROUND: Several studies have suggested an association between periodontal disease and prematurity but this finding has not been consistently observed. METHODS: Case control study. Cases (n = 50) were women who had delivered after spontaneous preterm labor at <35 weeks gestation. Two groups of controls (n = 101) were recruited: women who were undelivered but at a preterm gestation and

  4. Atom microscopy via two-photon spontaneous emission spectroscopy RID A-5077-2009

    E-print Network

    Qamar, Sajid; Evers, Joerg; Zubairy, M. Suhail

    2009-01-01

    We study subwavelength position measurement via spontaneous emission spectroscopy with two photons. Our model systems are a single Lambda-type three-level atom, in which a dual interaction generates two independent photons, and an M-type five...

  5. Controlled positions and kinetic analysis of spontaneous tin whisker growth

    NASA Astrophysics Data System (ADS)

    Su, Chien-Hao; Chen, Hao; Lee, Hsin-Yi; Wu, Albert T.

    2011-09-01

    This study achieved controlling the positions of spontaneous growth of tin whiskers. We surmounted the unpredictable growing nature of such whiskers and performed accurately quantitative analyses of the growth kinetics and yielded precise measurement of the growth rate. Furthermore, using synchrotron radiation x-ray, this study determined the stress variations in conjunction with whisker growth that fitted appropriately to the model. Accordingly, the results could address the debate held for decades and prove that forming a surface oxide layer is one of the required and necessary conditions for controlling the positions of spontaneous growth of tin whiskers.

  6. Controlled positions and kinetic analysis of spontaneous tin whisker growth

    SciTech Connect

    Su, Chien-Hao; Chen, Hao; Wu, Albert T. [Department of Chemical and Materials Engineering, National Central University, Jhongli City 320, Taiwan (China); Lee, Hsin-Yi [National Synchrotron Radiation Research Center, HsinChu City 300, Taiwan (China)

    2011-09-26

    This study achieved controlling the positions of spontaneous growth of tin whiskers. We surmounted the unpredictable growing nature of such whiskers and performed accurately quantitative analyses of the growth kinetics and yielded precise measurement of the growth rate. Furthermore, using synchrotron radiation x-ray, this study determined the stress variations in conjunction with whisker growth that fitted appropriately to the model. Accordingly, the results could address the debate held for decades and prove that forming a surface oxide layer is one of the required and necessary conditions for controlling the positions of spontaneous growth of tin whiskers.

  7. Spontaneous emission from a two-level atom in two-band anisotropic photonic crystals

    SciTech Connect

    Yang Yaping [Department of Physics, Tongji University, Shanghai 200092 (China); Fachbereich Physik, University Kaiserslautern, D-67663 Kaiserslautern (Germany); Department of Physics, Hongkong Baptist University, Hong Kong (China); Fleischhauer, M. [Fachbereich Physik, University Kaiserslautern, D-67663 Kaiserslautern (Germany); Zhu Shiyao [Department of Physics, Hongkong Baptist University, Hong Kong (China)

    2003-10-01

    We investigate the spontaneous radiation from a two-level atom embedded in a three-dimensional anisotropic photonic crystal with two bands. The properties of the spontaneous emission are dependent strongly on the position of the upper level. The faster and slower decay components can occur in the emitted field, but it does not mean the existence of both accelerated and inhibited components for the atomic population decay. The radiation spectrum is dependent on the location of the observer. We also study the influence of the existence of the two bands on spontaneous emission, Lamb shift, the emitted field, and the radiation spectrum.

  8. EMISSION CONTROL: CONTROL OF FINE PARTICULATE EMISSIONS

    EPA Science Inventory

    This paper reviews the results of fine particulate control technology tests by the Particulate Technology Branch (PATB) of EPA's IERL-RTP over the last 3 years. The review covers characterization of conventional control equipment, assessment of the collectability of dusts, and ne...

  9. Spontaneous emission of electromagnetic radiation in turbulent plasmas

    SciTech Connect

    Ziebell, L. F., E-mail: luiz.ziebell@ufrgs.br [Instituto de Física, UFRGS, Porto Alegre, Rio Grande do Sul (Brazil); Yoon, P. H., E-mail: yoonp@umd.edu [School of Space Research, Kyung Hee University, Yongin, Gyeonggi 446-701, South Korea and University of Maryland, College Park, Maryland 20742 (United States); Simões, F. J. R.; Pavan, J. [Instituto de Física e Matemática, UFPel, Pelotas, Rio Grande do Sul (Brazil)] [Instituto de Física e Matemática, UFPel, Pelotas, Rio Grande do Sul (Brazil); Gaelzer, R. [Instituto de Física, UFRGS, Porto Alegre, Rio Grande do Sul (Brazil) [Instituto de Física, UFRGS, Porto Alegre, Rio Grande do Sul (Brazil); Instituto de Física e Matemática, UFPel, Pelotas, Rio Grande do Sul (Brazil)

    2014-01-15

    Known radiation emission mechanisms in plasmas include bremmstrahlung (or free-free emission), gyro- and synchrotron radiation, cyclotron maser, and plasma emission. For unmagnetized plasmas, only bremmstrahlung and plasma emissions are viable. Of these, bremmstrahlung becomes inoperative in the absence of collisions, and the plasma emission requires the presence of electron beam, followed by various scattering and conversion processes. The present Letter proposes a new type of radiation emission process for plasmas in a state of thermodynamic quasi-equilibrium between particles and enhanced Langmuir turbulence. The radiation emission mechanism proposed in the present Letter is not predicted by the linear theory of thermal plasmas, but it relies on nonlinear wave-particle resonance processes. The electromagnetic particle-in-cell numerical simulation supports the new mechanism.

  10. 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.

  11. 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

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

    NASA Astrophysics Data System (ADS)

    Sumikura, Hisashi; Kuramochi, Eiichi; Taniyama, Hideaki; Notomi, Masaya

    2014-05-01

    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.

  13. 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

  14. Atomic spatial coherence with spontaneous emission in a strong-coupling cavity

    SciTech Connect

    Fang Zhen; Guo Rui; Zhou Xiaoji; Chen Xuzong [School of Electronics Engineering and Computer Science, Peking University, Beijing 100871 (China)

    2010-07-15

    The role of spontaneous emission in the interaction between a two-level atom and a pumped microcavity in the strong-coupling regime is discussed. In particular, using a quantum Monte Carlo simulation, we investigate atomic spatial coherence. It is found that atomic spontaneous emission destroys the coherence between neighboring lattice sites, while cavity decay does not. Furthermore, our computation of the spatial coherence function shows that the in-site locality is little affected by the cavity decay but greatly depends on the cavity pump amplitude.

  15. 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.

  16. Highly elevated emission of mercury vapor due to the spontaneous combustion of refuse in a landfill

    NASA Astrophysics Data System (ADS)

    Zhu, Wei; Sommar, Jonas; Li, Zhonggen; Feng, Xinbin; Lin, Che-Jen; Li, Guanghui

    2013-11-01

    Refuse disposal (e.g., landfilling and incineration) have been recognized as a significant anthropogenic source of mercury (Hg) emission globally. However, in-situ measurements of Hg emission from landfill or refuse dumping sites where fugitive spontaneous combustion occurs have not been reported. Gaseous elemental mercury (Hg0) concentration and emission flux were observed near spontaneous combustions of refuse at a landfill site in southwestern China. Ambient Hg0 concentrations above the refuse surface ranged from 42.7 ± 20.0 to 396.4 ± 114.2 ng m-3, up to 10 times enhancement due to the spontaneous burning. Using a box model with Hg0 data obtained from 2004 to 2013, we estimated that the Hg0 emission from refuse was amplified by 8-40 times due to spontaneous combustion. A micrometeorological flux measurement system based on relaxed eddy accumulation was configured downwind of the combustion sites to quantify the Hg0 emission. Extremely large turbulent deposition fluxes (up to -128.6 ?g m-2 h-1, 20 min average) were detected during periods of high Hg0 concentration events over the measurement footprint. The effect of temperature, moisture and light on the air-surface exchange of Hg0 exchange was found to be masked by the overwhelming deposition of Hg0 from the enriched air from the refuse combustion plumes. This research reveals that mercury emission from the landfill refuse can be boosted by fugitive spontaneous combustion of refuse. The emission represents an anthropogenic source that has been overlooked in Hg inventory estimates.

  17. 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.

  18. Spontaneous Incidence of Oncocytic Proliferative Lesions in Control Rat Kidney.

    PubMed

    Hard, Gordon C; Seely, John Curtis; Betz, Laura J

    2014-03-20

    The spontaneous incidence of foci of oncocytic proliferation (oncocytic hyperplasia and oncocytoma) was assessed in a histopathological reevaluation of the kidneys of 2,391 male and female Fischer 344 (F344) groups of control rats from long-term carcinogenicity studies (involving 24 chemicals) that had been conducted by the National Toxicology Program. The overall incidence of oncocytic proliferation was 0.3%, with a male preponderance over females at 0.5% (6/1,236) versus 0.09% (1/1,155), respectively. In males, there appeared to be an association of oncocytic proliferation with advanced spontaneous chronic progressive nephropathy. Oncocytoma or oncocytic hyperplasia appear to be rare lesions in F344 rats, and observations from these carcinogenicity studies suggest that they are slow growing and tend to occur late in a rodent's life span. PMID:24652082

  19. 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.

  20. Thermalization of strongly interacting bosons after spontaneous emissions in optical lattices

    E-print Network

    Johannes Schachenmayer; Lode Pollet; Matthias Troyer; Andrew J. Daley

    2014-08-05

    We study the out-of-equilibrium dynamics of bosonic atoms in a 1D optical lattice, after the ground-state is excited by a single spontaneous emission event, i.e. after an absorption and re-emission of a lattice photon. This is an important fundamental source of decoherence for current experiments, and understanding the resulting dynamics and changes in the many-body state is important for controlling heating in quantum simulators. Previously it was found that in the superfluid regime, simple observables relax to values that can be described by a thermal distribution on experimental time-scales, and that this breaks down for strong interactions (in the Mott insulator regime). Here we expand on this result, investigating the relaxation of the momentum distribution as a function of time, and discussing the relationship to eigenstate thermalization. For the strongly interacting limit, we provide an analytical analysis for the behavior of the system, based on an effective low-energy Hamiltonian in which the dynamics can be understood based on correlated doublon-holon pairs.

  1. 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

  2. PHYSICAL REVIEW B 86, 245322 (2012) Collective spontaneous emission in coupled quantum dots: Physical mechanism

    E-print Network

    Nabben, Reinhard

    2012-01-01

    Maksimenko Institute for Nuclear Problems, Belarus State University, 11 Bobruiskaya Str., 220050 Minsk, Belarus A. Hoffmann Institut f¨ur Festk¨orperphysik, Technische Universit¨at Berlin Hardenbergstr. 36, D the collective spontaneous emission in a system of two identical quantum dots (QDs) strongly coupled through

  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 displacement and the attenuation of the external luminescence intensity as a function of applied bias voltage lifetime of the semiconductor.1 Several inves- tigators have attempted to increase the speed of LEDs using

  4. Mammalian spontaneous otoacoustic emissions are amplitude-stabilized cochlear standing waves

    E-print Network

    Allen, Jont

    Mammalian spontaneous otoacoustic emissions are amplitude- stabilized cochlear standing waves suppose that SOAEs are a global collective phenomenon--cochlear standing waves created by multiple'' standing-wave model supposes that SOAEs are biological noise, passively amplified by cochlear standing-wave

  5. Glycol dehydrator emission control improved

    SciTech Connect

    Fisher, K.S.; Rueter, C. (Radian Corp., Austin, TX (United States)); Lyon, M. (Public Service Co. of Colorado, Denver, CO (United States)); Gamez, J. (Gas Research Inst., Chicago, IL (United States))

    1995-02-27

    For natural gas glycol dehydrators, evaporative cooling provides better emission control than conventional air cooled or glycol-cooled condensation technologies. Recent developments in environmental regulations, including the upcoming Maximum Achievable Control Technology (MACT) standards, have made emissions of benzene, ethylbenzene, toluene, and xylenes (BTEX) from glycol dehydrators a major concern for the natural gas industry. This concern has led the gas industry to look for new ways to reduce and control hydrocarbon emissions from these systems. Gas Research institute (GRI) has sponsored the development of the R-BTEX process, which uses evaporative cooling. The paper discusses available technology and then describes the advantages of the R-BTEX process.

  6. Atomic nuclei decay modes by spontaneous emission of heavy ions

    NASA Astrophysics Data System (ADS)

    Poenaru, D. N.; Iva?cu, M.; Sndulescu, A.; Greiner, Walter

    1985-08-01

    The great majority of the known nuclides with Z>40, including the so-called stable nuclides, are metastable with respect to several modes of spontaneous superasymmetric splitting. A model extended from the fission theory of alpha decay allows one to estimate the lifetimes and the branching ratios relative to the alpha decay for these natural radioactivities. From a huge amount of systematic calculations it is concluded that the process should proceed with maximum intensity in the trans-lead nuclei, where the minimum lifetime is obtained from parent-emitted heavy ion combinations leading to a magic (208Pb) or almost magic daughter nucleus. More than 140 nuclides with atomic number smaller than 25 are possible candidates to be emitted from heavy nuclei, with half-lives in the range of 1010-1030 s: 5He, 8-10Be, 11,12B, 12-16C, 13-17N, 15-22O, 18-23F, 20-26Ne, 23-28Na, 23-30Mg, 27-32Al, 28-36Si, 31-39P, 32-42S, 35-45Cl, 37-47Ar, 40-49 K, 42-51. . .Ca, 44-53 Sc, 46-53Ti, 48-54V, and 49-55 Cr. The shell structure and the pairing effects are clearly manifested in these new decay modes.

  7. The interplay between spontaneous and controlled processing in creative cognition

    PubMed Central

    Mok, Leh Woon

    2014-01-01

    Neural studies of creativity have yielded relatively little consistent results. For example, in functional neuroanatomical studies, the prefrontal cortex (PFC) has often been implicated as a critical neural substrate. However, results in electrophysiological (EEG) studies have been inconsistent as to the role of the PFC. EEG results have more often implicated widespread alpha synchronization, particularly in posterior regions, in creative cognition. Recent fMRI evidence has indicated that the PFC may be activated as a part of and together with other components of a deliberate control brain network. Controlled processing is neurologically dissociated from, but may co-occur with, spontaneous cognition mediated by a subset of the default-mode network (e.g., the angular gyrus [BA 39] in the posterior parietal cortex, which has been increasingly implicated in creative cognition). When the demand for controlled processing is substantially increased, default-mode processing may be suppressed. There is now preliminary evidence to suggest an association between alpha synchronization and default-mode processing. Creative cognition likely emerges from an optimal balance between spontaneous processing and controlled processing. PMID:25221497

  8. Ultraweak, spontaneous photon emission in seedlings: toxicological and chronobiological applications.

    PubMed

    de Mello Gallep, Cristiano

    2014-12-01

    The detection of ultraweak light emission in seedlings has been explored in toxicological and chronobiological studies. The main studies in this area are reviewed briefly, including a report on applied tests held in the last 7 years at LaFA--UNICAMP (Brazil). In general, results indicate that a linear relation for total light emission versus germination performance is found if only strong stress situations are considered, when external factors depress a seedling's development, even when considering a sequential series of tests. Light emitted by a single seedling was detected in a compact apparatus, and data are presented here for the first time showing pronounced circadian cycles are evident, with similar time and frequency profiles as those of the local gravimetric tide. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24687546

  9. 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

  10. Spontaneous ultraweak photon emission imaging of oxidative metabolic processes in human skin: effect of molecular oxygen and antioxidant defense system

    NASA Astrophysics Data System (ADS)

    Rastogi, Anshu; Pospíšil, Pavel

    2011-09-01

    All living organisms emit spontaneous ultraweak photon emission as a result of cellular metabolic processes. In this study, the involvement of reactive oxygen species (ROS) formed as the byproduct of oxidative metabolic processes in spontaneous ultraweak photon emission was studied in human hand skin. The effect of molecular oxygen and ROS scavengers on spontaneous ultraweak photon emission from human skin was monitored using a highly sensitive photomultiplier tube and charged coupled device camera. When spontaneous ultraweak photon emission was measured under anaerobic conditions, the photon emission was decreased, whereas under hyperaerobic condition the enhancement in photon emission was observed. Spontaneous ultraweak photon emission measured after topical application of glutathione, ?-tocopherol, ascorbate, and coenzyme Q10 was observed to be decreased. These results reveal that ROS formed during the cellular metabolic processes in the epidermal cells play a significant role in the spontaneous ultraweak photon emission. It is proposed that spontaneous ultraweak photon emission can be used as a noninvasive tool for the temporal and spatial monitoring of the oxidative metabolic processes and intrinsic antioxidant system in human skin.

  11. Emission control system

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

    Methods and apparatus utilizing hydrogen peroxide are useful to reduce SOx and mercury (or other heavy metal) emissions from combustion flue gas streams. The methods and apparatus may further be modified to reduce NOx emissions. Continuous concentration of hydrogen peroxide to levels approaching or exceeding propellant-grade hydrogen peroxide facilitates increased system efficiency. In this manner, combustion flue gas streams can be treated for the removal of SOx and heavy metals, while isolating useful by-products streams of sulfuric acid as well as solids for the recovery of the heavy metals. Where removal of NOx emissions is included, nitric acid may also be isolated for use in fertilizer or other industrial applications.

  12. Two-dimensional atom localization via spontaneous emission in a coherently driven five-level M-type atomic system

    SciTech Connect

    Ding Chunling; Li Jiahua; Yang Xiaoxue [Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhan Zhiming [School of Physics and Information Engineering, Jianghan University, Wuhan 430056 (China)

    2011-06-15

    A scheme is proposed for two-dimensional atom localization in the subwavelength domain via controlled spontaneous emission. We consider a five-level M-type atomic system interacting with two orthogonal standing-wave laser fields and the vacuum of the radiation field. The interaction of the atom with space-dependent standing-wave fields can provide information about the position of the atom passing through, thus leading to atom localization. It is found that the localization is significantly improved due to the interference effect between the spontaneous decay channels and the dynamically induced quantum interference generated by the two standing-wave fields. By properly varying the system parameters, we can achieve high-precision and high-resolution atom localization.

  13. Amplified spontaneous emission of glass forming DCM derivatives in PMMA films

    NASA Astrophysics Data System (ADS)

    Vembris, Aivars; Zarinsh, Elmars; Kokars, Valdis

    2014-05-01

    4-(dicyanomethylene)-2-methyl- 6-(p-dimethylaminostyryl)-4H-pyran (DCM) is well known red laser dye which can be used also in solid state organic lasers. The lowest threshold value of amplified spontaneous emission was achieved by doping 2wt% of DCM molecule in tris-(8-hydroxy quinoline) aluminium (Alq3) matrix. Further increase of dye concentration also increases threshold value. It is due to large intermolecular interaction which reduce photoluminescence quantum yield. Compounds with small intermolecular interaction and which exhibit similar amplified spontaneous properties as DCM could be useful for solid state organic lasers. In the work photoluminescence and amplified spontaneous emission properties of two DCM derivatives in poly (methyl methacrylate) (PMMA) matrix were investigated. Bulky trityloxyethyl groups are attached to the donor part of investigated molecules. These groups reduce intermolecular distance wherewith reduce photoluminescence quenching. More than one order of magnitude lower excitation threshold energy of the amplified spontaneous emission was achieved in doped polymer films with investigated compound in comparison to doped polymer with DCM. It means that the investigated compound is more perspective as a laser material compared to previously study.

  14. Advanced Emissions Control Development Program: Mercury Control

    Microsoft Academic Search

    A. P. Evans; K. W. Redinger; M. J. Holmes

    1997-01-01

    McDermott Technology, Inc. (a subsidiary of Babcock & Wilcox) is conducting the Advanced Emissions Control Development Project (AECDP) which is aimed at the development of practical, cost-effective strategies for reducing the emissions of hazardous air pollutants (HAPS) from coal-fired electric utility plants. The need for such controls may arise as the US Environmental Protection Agency (EPA) proceeds with implementation of

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

    PubMed Central

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

    2014-01-01

    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, are no longer detrimental, but necessary for three-dimensional entangled state preparation without specifying initial state and controlling the evolution time precisely. Final numerical simulation with one group of experimental parameters indicates that the performance of our scheme could be better than the unitary-dynamics-based scheme. PMID:25523944

  16. 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.

  17. Emission control system

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2008-01-01

    Methods and apparatus utilizing hydrogen peroxide are useful to reduce NOx, SOx and mercury (or other heavy metal) emissions from combustion flue gas streams. Continuous concentration of hydrogen peroxide to levels approaching or exceeding propellant-grade hydrogen peroxide facilitates increased system efficiency. In this manner, combustion flue gas streams can be treated for the removal of NOx, SOx and heavy metals, while isolating useful by-products streams of sulfuric acid and nitric acid as well as solids for the recovery of the heavy metals.

  18. 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.

  19. Advanced Emissions Control Development Program

    SciTech Connect

    A.P.Evans; K.E. Redinger; M.J. Holmes

    1998-04-01

    The 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. Ideally, the project aim is to effectively control air toxic emissions through the use of conventional flue gas cleanup equipment such as electrostatic precipitators (ESPS), fabric filters (baghouse), and wet flue gas desulfurization. Development work to date has concentrated on the capture of mercury, other trace metals, fine particulate and hydrogen chloride. Following the construction and evaluation of a representative air toxics test facility in Phase I, Phase II focused on the evaluation of mercury and several other air toxics emissions. The AECDP is jointly funded by the United States Department of Energy's Federal Energy Technology Center (DOE), the Ohio Coal Development Office within the Ohio Department of Development (oCDO), and Babcock& Wilcox-a McDermott company (B&W).

  20. 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.

  1. The dynamics of amplified spontaneous emission in CdSe/ZnSe quantum dots

    E-print Network

    Kundys, D O; Wells, J P R; Tartakovskii, A I; Skolnick, M S; Dang, Le Si; Lutsenko, E V; Tarasuk, N P; Lyublinskaya, O G; Toropov, A A; Ivanov, S V

    2014-01-01

    We have used the variable stripe technique and pump-probe spectroscopy to investigate both gain and the dynamics of amplified spontaneous emission from CdSe quantum dot structures. We have found modal gain coefficients of 75 and 32 1/cm for asymmetric and symmetric waveguide structures, respectively. Amplified spontaneous emission decay times of 150 and 300 ps and carrier capture times of 15 and 40 ps were measured for the structures with high and low material gains respectively. The difference in the capture times are related to the fact that for the symmetric waveguide, carriers diffuse into the active region from the uppermost ZnMgSSe cladding layer, yielding a longer rise time for the pump-probe signals for this sample.

  2. Cavity-enhanced spontaneous emission rates for rhodamine 6-G in levitated microdroplets

    SciTech Connect

    Barnes, M.D.; Whitten, W.B.; Ramsey, J.M. (Oak Ridge National Lab., TN (United States)); Arnold, S. (Polytechnic Inst., of New York, Brooklyn, NY Microparticle Photophysics Lab. (United States))

    1992-01-01

    Fluorescence decay kinetics of Rhodamine 6-G molecules in levitated glycerol microdroplets (4--20 microns in diameter) have been investigated to determine the effects of spherical cavity resonances on spontaneous emission rates. For droplet diameters greater than 10 microns, the fluorescence lifetime is essentially the same as in bulk glycerol. As the droplet diameter is decreased below 10 microns, bi-exponential decay behavior is observed with a slow component whose rate is similar to bulk glycerol, and a fast component whose rate is as much as a factor of 10 larger than the bulk decay rate. This fast component is attributed to cavity enhancement of the spontaneous emission rate and, within the weak coupling approximation, a value for the homogeneous linewidth at room temperature can be estimated from the fluorescence lifetime data.

  3. Cavity-enhanced spontaneous emission rates for rhodamine 6-G in levitated microdroplets

    SciTech Connect

    Barnes, M.D.; Whitten, W.B.; Ramsey, J.M. [Oak Ridge National Lab., TN (United States); Arnold, S. [Polytechnic Inst., of New York, Brooklyn, NY Microparticle Photophysics Lab. (United States)

    1992-11-01

    Fluorescence decay kinetics of Rhodamine 6-G molecules in levitated glycerol microdroplets (4--20 microns in diameter) have been investigated to determine the effects of spherical cavity resonances on spontaneous emission rates. For droplet diameters greater than 10 microns, the fluorescence lifetime is essentially the same as in bulk glycerol. As the droplet diameter is decreased below 10 microns, bi-exponential decay behavior is observed with a slow component whose rate is similar to bulk glycerol, and a fast component whose rate is as much as a factor of 10 larger than the bulk decay rate. This fast component is attributed to cavity enhancement of the spontaneous emission rate and, within the weak coupling approximation, a value for the homogeneous linewidth at room temperature can be estimated from the fluorescence lifetime data.

  4. Spontaneous emission properties of a driven five-level atom embedded in photonic crystals

    NASA Astrophysics Data System (ADS)

    Zhang, Duo; Li, Jiahua; Ding, Chunling; Yang, Xiaoxue

    2012-08-01

    The spontaneous emission spectra of a five-level double tripod-type atom embedded in photonic crystals (PCs) are investigated by means of two external fields driving different atomic transitions. We find that due to the quantum interference effects caused by two driving fields, the spontaneous emission spectra exhibit different features from the case of only one driving field. The influences of the parameters of two external driving fields, photonic band-gap (PBG), as well as the atomic initial states on the spectra are analyzed in detail. It is shown that some interesting phenomena such as spectral-line enhancement, spectral-line suppression, spectral-line narrowing, the appearance of dark lines, and multi-peak structures can be observed in the spectra by appropriately modulating the available system parameters. These investigations may find applications in high-precision spectroscopy.

  5. 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.

  6. Spontaneous Emission Alteration Near the One-Dimensional Photonic Band Edge of Semiconductor Heterostructures

    Microsoft Academic Search

    Michael David Tocci

    1995-01-01

    The alteration of the spontaneous emission of GaAs from within a photonic band gap structure is described and experimentally demonstrated. GaAs is used as an emitting layer in a typical p-i-n light emitting diode, and AlGaAs and AlAs are used in an alternating sequence on either side of the emitting layer to form a photonic band gap structure. The thickness

  7. 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

  8. Temporal coherence of a photonic crystal nanocavity laser with high spontaneous emission coupling factor

    Microsoft Academic Search

    Masahiro Nomura; Satoshi Iwamoto; Naoto Kumagai; Yasuhiko Arakawa

    2007-01-01

    Temporal coherence of a continuous-wave photonic crystal nanocavity laser is investigated in detail using interference experiments at room temperature. The nanocavity laser operates at 1.3mum with InAs quantum dot gain material and has a very high spontaneous emission coupling factor beta=0.9 with a threshold absorbed pump power of ˜375nW . The coherence around the laser threshold of such a high-

  9. Amplification of spontaneous emission in erbium-doped single-mode fibers

    Microsoft Academic Search

    Emmanuel Desurvire; JAY R. SIMPSON

    1989-01-01

    Amplification of spontaneous emission (ASE) in erbium-doped single-mode fiber amplifiers operating at ?=1.53 ?m is studied theoretically and experimentally. The ASE noise spectra obtained from the theory are found to be in excellent quantitative agreement with the experimental data. The observed changes in ASE spectral shapes under different population inversion conditions are also explained. The model may be used to

  10. Amplified spontaneous emission and Rayleigh backscattering in strongly pumped fiber amplifiers

    Microsoft Academic Search

    Amos A. Hardy; Ram Oron

    1998-01-01

    Amplified spontaneous emission (ASE) and Rayleigh backscattering (RBS) in strongly pumped fiber amplifiers are studied, employing a rate equation model. Approximate expressions for the ASE and RES, as well as for the amplifier noise figure are derived, based on approximate analytical expressions for the amplified signal, which are valid for both three-level and four-level systems. Numerical examples for rare-earth-doped fibers,

  11. Amplified spontaneous emission from single CdS nanoribbon with low symmetric cross sections.

    PubMed

    Xu, Xin Long; Wang, Jian Xiong; Jing, Guang Yin; Shen, Ze Xiang; Zou, Bing Suo; Fan, Hai Ming; Olivo, Malini

    2012-09-21

    CdS nanoribbons with various cross sections offer the opportunity to deeply understand the interaction between optical cavity and spontaneous emission. Herein, long tapered nanoribbons with the cross sections gradually changing were synthesized by a simple physical vapour deposition method. Morphology dependent micro-region photoluminescence (PL) spectroscopy is employed to show Purcell effect along different low symmetry cross sections. Spikes on the PL spectra reveal that local density of optical modes increases when the mode match happens between optical cavity and spontaneous emission. Bound exciton complex related amplified spontaneous emission is observed in a single CdS nanoribbon with well-defined elliptical cross sections and optimized width/thickness ratio ?1.45. Polarized Raman and TEM confirmed that the nanoribbon with the elliptical cross section adopts the [0002] growth direction with good quality. The results suggest that the cross section resonant cavity would be of importance for both fundamental and practical application of cavity quantum electrodynamics in CdS nanoribbon. PMID:22868895

  12. Spatially adjusted spontaneous emissions from photonic crystals embedded light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Yin, Yu-Feng; Lin, Yen-Chen; Liu, Yi-Chen; Chiang, Hai-Pang; Huang, JianJang

    2014-09-01

    In this work, the angular light output enhancements of LEDs were investigated from the spontaneous emission and light scattering of devices with different photonic crystal (PhC) geometries. The emitted photon coupled into a leaky mode is differentiated by the manipulation of the quality factor in various spatial frequencies. Therefore, light extraction in this light-emitting device is determined by the modal extraction lengths and the quality factor obtained from the measured photonic bands. Furthermore, the higher- and lower-order mode spontaneous emissions are affected by the nonradiative process in the PhC structures with different periods. In our cases, the photonic crystal device with the largest period of 500 nm exhibits the highest lower-order mode extraction and quality factor. As a result, a self-collimation behavior toward the surface-normal is demonstrated in the 3D far-field pattern of such a device. We conclude that, with the coherent light scattering from the PhC region, the spontaneous emission of the material and spatial behavior of the extracted mode can be both managed by the proper design of the device.

  13. 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.

  14. 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.

  15. Advanced Emissions Control Development Program

    SciTech Connect

    A. P. Evans

    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 the inorganic species, hydrogen chloride and hydrogen fluoride.

  16. Spontaneous Neoplasms in Control Wistar Rats: A Comparison

    E-print Network

    James Poteracki; Kathleen M. Walsh; Of Reviews Poteracki

    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 and 415 (89%) female rats; 1293 (81%) of these were benign and 306 (19%) were malignant (11 % with metastases). Sixty-eight percent of all neoplasms were in endocrine and integumentary systems, similar to 74 % seen in the previous review. Most common neoplasms (affecting>7 % of either sex) were pituitary adenoma (34 % of males, 50 % of females), benign adrenal pheochromocytoma (10 % of males, 1 % of females), thyroid C cell adenoma (6 % of males, 8 % of females), mammary fibroadenoma (3 % of males, 36 % of females), keratoacanthoma

  17. Greenhouse gas emissions from Australian open-cut coal mines: contribution from spontaneous combustion and low-temperature oxidation.

    PubMed

    Day, Stuart J; Carras, John N; Fry, Robyn; Williams, David J

    2010-07-01

    Spontaneous combustion and low-temperature oxidation of waste coal and other carbonaceous material at open-cut coal mines are potentially significant sources of greenhouse gas emissions. However, the magnitude of these emissions is largely unknown. In this study, emissions from spontaneous combustion and low-temperature oxidation were estimated for six Australian open-cut coal mines with annual coal production ranging from 1.7 to more than 16 Mt. Greenhouse emissions from all other sources at these mines were also estimated and compared to those from spontaneous combustion and low-temperature oxidation. In all cases, fugitive emission of methane was the largest source of greenhouse gas; however, in some mines, spontaneous combustion accounted for almost a third of all emissions. For one mine, it was estimated that emissions from spontaneous combustion were around 250,000 t CO(2)-e per annum. The contribution from low-temperature oxidation was generally less than about 1% of the total for all six mines. Estimating areas of spoil affected by spontaneous combustion by ground-based surveys was prone to under-report the area. Airborne infrared imaging appears to be a more reliable method. PMID:19572109

  18. Spontaneous emission of “polarized” V-type three-level atoms strongly coupled with an optical cavity

    NASA Astrophysics Data System (ADS)

    Xue, Yan-Li; Zhu, Shi-Deng; Li, Jia-Fang; Ding, Wei; Feng, Bao-Hua; Li, Zhi-Yuan

    2015-03-01

    Polarization, an intrinsic ingredient of photon, plays a critical role in its interaction with matter. A general polarization state can be an appropriate superposition of two basic polarization states, say, the vertical and horizontal linear polarized state. Here we study spontaneous emission of a V-type three-level atom (with two upper states close in energy level) strongly coupled with a single-mode damped optical cavity. By defining a general polarization state of atom as a specific superposition of the two upper quantum states, we can prepare atoms with linear polarization at arbitrary direction, left and right circular polarization, and left and right elliptical polarization, similar to photons. We find that the spontaneous emission of light from these “polarized” three-level atoms shows very different profiles of side and axis spectra. This means that the polarization state of three-level atoms can become an active ingredient to manipulate its interaction with light and control the quantum interference effect. Exploitation of the coherent superposition and interference of quantum states in “polarized” atoms would allow one to deeply explore new frontiers of light–matter interaction. Project supported by the National Basic Research Foundation of China (Grant No. 2011CB922002).

  19. Spontaneous emission spectrum of a two-level atom in a very high Q cavity

    E-print Network

    Alexia Auffèves; Benjamin Besga; Jean-Michel Gérard; Jean-Philippe Poizat

    2008-05-20

    In this paper we consider an initially excited two-level system coupled to a monomode cavity, and compute exact expressions for the spectra spontaneously emitted by each system in the general case where they have arbitrary linewidths and frequencies. Our method is based on the fact that this problem has an easily solvable classical counterpart, which provides a clear interpretation of the evidenced phenomena. We show that if the cavity linewidth is much lower than the atomic linewidth, photons are emitted at the cavity frequency, even if the atom and the cavity are strongly detuned. We also study the links between the spontaneous emission spectra and the fluorescence spectra emitted when the atom is driven by a classical field of tunable frequency.

  20. Microscopic Theory of Optical Nonlinearities and Spontaneous Emission Lifetime in Group-III Nitride Quantum Wells

    SciTech Connect

    Chow, W.; Kira, M.; Koch, S.W.

    1999-03-16

    Microscopic calculations of the absorption/gain and luminescence spectra are presented for wide bandgap Ga{sub 1{minus}x}In{sub x}N/GaN quantum well systems. Whereas structures with narrow well widths exhibit the usual excitation dependent bleaching of the exciton resonance without shifting spectral position, a significant blue shift of the exciton peak is obtained for wider quantum wells. This blue shift, which is also present in the excitation dependent luminescence spectra, is attributed to the interplay between the screening of a strain induced piezoelectric field and the density dependence of many-body Coulomb effects. The calculations also show an over two orders of magnitude increase in the spontaneous electron-hole-pair lifetime with well width: due to the reduction of the electron-hole wavefunction overlap in the wider wells. The resulting decrease in spontaneous emission loss is predicted to lead to improved threshold properties in wide quantum well lasers.

  1. 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.

  2. Bremsstrahlung emission of high energy accompanying spontaneous fission of {sup 252}Cf

    SciTech Connect

    Maydanyuk, S. P.; Olkhovsky, V. S.; Mandaglio, G.; Manganaro, M.; Fazio, G.; Giardina, G. [Institute for Nuclear Research, National Academy of Science of Ukraine, Kiev 03680 (Ukraine); Dipartimento di Fisica dell'Universita di Messina, I-98166 Messina (Italy) and Istituto Nazionale di Fisica Nucleare, Sezione di Catania, I-95123 Catania (Italy)

    2010-07-15

    The study of the bremsstrahlung photon emission accompanying fragments produced in the spontaneous fission of heavy nuclei by a fully quantum approach is presented for the first time. This kind of problem requires the knowledge of wave functions of the fissioning system leading to a wide distribution of couples of fragments that are the products of fission. With the aim of obtaining these wave functions, the interaction potential between the emitted fragment and residual nucleus is calculated by a standard approach. A new procedure was performed that allows an increase in the accuracy of calculations of radial integrals in the far asymptotic region and the achievement of the convenient convergence in calculations of the spectra. The total probability of the emitted photons in the spontaneous fission of {sup 252}Cf was calculated in such a way. We obtained good agreement between theory and experimental data up to 38 MeV for the bremsstrahlung spectrum of photons while the calculation of the total probability of photon emission accompanying fragments was performed up to an energy of 60 MeV. The analysis of contributions in the bremsstrahlung spectrum accompanying the emission of light, medium, and heavy fragments in the fission of {sup 252}Cf is presented.

  3. 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

  4. Spontaneous emission from a two--level atom tunneling in a double--well potential

    E-print Network

    Daniel Braun; John Martin

    2007-10-26

    We study a two-level atom in a double--well potential coupled to a continuum of electromagnetic modes (black body radiation in three dimensions at zero absolute temperature). Internal and external degrees of the atom couple due to recoil during emission of a photon. We provide a full analysis of the problem in the long wavelengths limit up to the border of the Lamb-Dicke regime, including a study of the internal dynamics of the atom (spontaneous emission), the tunneling motion, and the electric field of the emitted photon. The tunneling process itself may or may not decohere depending on the wavelength corresponding to the internal transition compared to the distance between the two wells of the external potential, as well as on the spontaneous emission rate compared to the tunneling frequency. Interference fringes appear in the emitted light from a tunneling atom, or an atom in a stationary coherent superposition of its center--of--mass motion, if the wavelength is comparable to the well separation, but only if the external state of the atom is post-selected.

  5. An active oscillator model describes the statistics of spontaneous otoacoustic emissions.

    PubMed

    Fruth, Florian; Jülicher, Frank; Lindner, Benjamin

    2014-08-19

    Even in the absence of external stimulation, the cochleas of most humans emit very faint sounds below the threshold of hearing, sounds that are known as spontaneous otoacoustic emissions. They are a signature of the active amplification mechanism in the cochlea. Emissions occur at frequencies that are unique for an individual and change little over time. The statistics of a population of ears exhibit characteristic features such as a preferred relative frequency distance between emissions (interemission intervals). We propose a simplified cochlea model comprising an array of active nonlinear oscillators coupled both hydrodynamically and viscoelastically. The oscillators are subject to a weak spatial disorder that lends individuality to the simulated cochlea. Our model captures basic statistical features of the emissions: distributions of 1), emission frequencies; 2), number of emissions per ear; and 3), interemission intervals. In addition, the model reproduces systematic changes of the interemission intervals with frequency. We show that the mechanism for the preferred interemission interval in our model is the occurrence of synchronized clusters of oscillators. PMID:25140416

  6. Cavity-induced coherence effects in spontaneous emission from pre-Selection of polarization

    E-print Network

    Anil K. Patnaik; G. S. Agarwal

    1999-03-28

    Spontaneous emission can create coherences in a multilevel atom having close lying levels, subject to the condition that the atomic dipole matrix elements are non-orthogonal. This condition is rarely met in atomic systems. We report the possibility of bypassing this condition and thereby creating coherences by letting the atom with orthogonal dipoles to interact with the vacuum of a pre-selected polarized cavity mode rather than the free space vacuum. We derive a master equation for the reduced density operator of a model four level atomic system, and obtain its analytical solution to describe the interference effects. We report the quantum beat structure in the populations.

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    We demonstrate an approach, based on plasmonic apertures and gratings, to enhance the radiative decay rate of single nitrogen-vacancy (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.

  8. Optical cavity temperature measurement based on the first overtones spontaneous emission spectra for HF chemical laser

    NASA Astrophysics Data System (ADS)

    Tang, Shukai; Li, Liucheng; Duo, Liping; Wang, Yuanhu; Yu, Haijun; Jin, Yuqi; Sang, Fengting

    2015-02-01

    An optical cavity temperature test method has been established for the HF chemical laser. This method assumes that in HF optical cavity the rotational distribution of vibrationally excited HF molecules meets the statistical thermodynamic distribution, the first overtones (v = 3-1 and 2-0) spontaneous emission spectral intensity distribution is obtained by using OMA V, the optical cavity temperature is calculated by linear fitting the rotational thermal equilibrium distribution formula for each HF vibrationally excited state. This method is simple, reliable, and repeatable. This method can be used to test the optical cavity temperature not only without lasing, but also with lasing.

  9. Local field corrections to the spontaneous emission in arrays of Si nanocrystals

    NASA Astrophysics Data System (ADS)

    Poddubny, Alexander N.

    2015-03-01

    We present a theory of the local field corrections to the spontaneous emission rate for the array of silicon nanocrystals in silicon dioxide. An analytical result for the Purcell factor is obtained. We demonstrate that the local-field corrections are sensitive to the volume fill factor of the nanocrystals in the sample and are suppressed for large values of the fill factor. The local-field corrections and the photonic density of states are shown to be described by two different effective permittivities: the harmonic mean between the nanocrystal and the matrix permittivities and the Maxwell–Garnett permittivity.

  10. Spontaneous emission and lifetime modification caused by an intense electromagnetic field

    E-print Network

    P. Facchi; S. Pascazio

    2000-03-28

    We study the temporal evolution of a three-level system (such as an atom or a molecule), initially prepared in an excited state, bathed in a laser field tuned at the transition frequency of the other level. The features of the spontaneous emission are investigated and the lifetime of the initial state is evaluated: a Fermi "golden rule" still applies, but the on-shell matrix elements depend on the intensity of the laser field. In general, the lifetime is a decreasing function of the laser intensity. The phenomenon we discuss can be viewed as an "inverse" quantum Zeno effect and can be analyzed in terms of dressed states.

  11. Modified spontaneous emission of organic molecules in-filled in inverse opals.

    PubMed

    Deng, Lier; Wang, Yongsheng; He, Dawei

    2011-11-01

    Inverse opals were prepared by replication of colloidal crystal templates made from silica spheres 298 nm in diameter. The air between the silica spheres was filled with the mixture of the monomer poly(methyl methacrylate) (PMMA) and the organic molecule Alq3 that can be subsequently polymerized. After removing the silica sphere templates, the photonic bandgap effect on the spontaneous emission of Alq3 were investigated. The dip in the fluorescence spectrum was interpreted in terms of redistribution of the photon density of states in the photonic crystal. PMID:22413286

  12. 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.

  13. 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... between levels #5;a#6;-#5;b#6; and #5;b#6;-#5;c#6; at frequencies #1;1 and #1;2 are resonant with the cavity. The transition #5;a#6;-#5;c#6; is dipole forbidden and can be induced by a strong magnetic field. QAMAR, XIONG, AND ZUBAIRY PHYSICAL REVIEW A...

  14. Spontaneous Emission and the Concept of Effective Area in a Very Short Optical Cavity with Plane-Parallel Dielectric Mirrors

    Microsoft Academic Search

    Kikuo Ujihara

    1991-01-01

    Spontaneous emission in a model cavity with very short length and with plane-parallel dielectric mirrors is calculated quantum-mechanically under perturbation approximation. Outgoing modes as well as guided modes are considered. Results on the directivity and the rate of emission into outer space are compared with the estimate by Purcell's method. This leads to the concept of ``effective area'' of the

  15. Amplified spontaneous emission and lasing from lanthanide-doped up-conversion nanocrystals.

    PubMed

    Zhu, Hai; Chen, Xian; Jin, Li Min; Wang, Qi Jie; Wang, Feng; Yu, Siu Fung

    2013-12-23

    Lanthanide-doped nanocrystals (NCs), which found applications in bioimaging and labeling, have recently demonstrated significant improvement in up-conversion efficiency. Here, we report the first up-conversion multicolor microcavity lasers by using NaYF4:Yb/Er@NaYF4 core-shell NCs as the gain medium. It is shown that the optical gain of the NCs, which arises from the 2- and 3-photon up-conversion processes, can be maximized via sequential pulses pumping. Amplified spontaneous emission is observed from a Fabry-Perot cavity containing the NCs dispersed in cyclohexane solution. By coating a drop of silica resin containing the NCs onto an optical fiber, a microcavity with a bottle-like geometry is fabricated. It is demonstrated that the microcavity supports lasing emission through the formation of whispering gallery modes. PMID:24266853

  16. Plasma effects on the spontaneous emission of synchrotron radiation from weakly relativistic electrons

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    A method for computing the spectral emissivity of spontaneous synchrotron radiation is discussed. The Klimontovich (1967) formalism in plasma kinetic theory is adopted in which an ensemble average of the microscopically emitted power is considered. The present method clarifies the meaning of the random phase approximation which is imposed in several existing theories of synchrotron radiation. Both the effects of dielectric polarization and two-particle correlations are included in the present discussion. The theory is applied to the case of a plasma in thermal equilibrium, for which it is shown that the effect of pair correlations on the emissivity vanishes. On the other hand, the effect of dielectric polarization is studied numerically for a wide range of parameters.

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

    SciTech Connect

    Donadi, Sandro, E-mail: sandro.donadi@ts.infn.it [Department of Physics, University of Trieste, Strada Costiera 11, 34151 Trieste (Italy) [Department of Physics, University of Trieste, Strada Costiera 11, 34151 Trieste (Italy); Istituto Nazionale di Fisica Nucleare, Trieste Section, Via Valerio 2, 34127 Trieste (Italy); Deckert, Dirk-André, E-mail: deckert@math.ucdavis.edu [Department of Mathematics, University of California, One Shields Ave, 95616 Davis (United States)] [Department of Mathematics, University of California, One Shields Ave, 95616 Davis (United States); Bassi, Angelo, E-mail: bassi@ts.infn.it [Department of Physics, University of Trieste, Strada Costiera 11, 34151 Trieste (Italy) [Department of Physics, University of Trieste, Strada Costiera 11, 34151 Trieste (Italy); Istituto Nazionale di Fisica Nucleare, Trieste Section, Via Valerio 2, 34127 Trieste (Italy)

    2014-01-15

    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). -- Highlights: •We compute the electromagnetic radiation emission in collapse models. •Under only the dipole approximation, the equations of motion are solved exactly. •The electromagnetic interaction must be treated exactly. •In order to obtain the correct emission rate the particle must be bounded.

  18. 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

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

    E-print Network

    S. Donadi; A. Bassi; D. -A. Deckert

    2013-07-03

    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 [1], 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 [1], it was shown that the unphysical term disappears when the noises is confined to a bounded region and the final particle's state is a wave packet. Here we investigate the origin of the unphysical term and why it vanishes according to the previous prescription. For this purpose, the electrodynamic part of the equation of motion is solved exactly while the part due to the noise is treated perturbatively. We show that the unphysical term is connected to exponentially decaying function of time which dies out in the large time limit, however, approximates to 1 in the first perturbative order in the electromagnetic field.

  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. 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

  2. Effects of spontaneous otoacoustic emissions on pure-tone frequency difference limens.

    PubMed

    Hansen, Rói; Santurette, Sébastien; Verhulst, Sarah

    2014-12-01

    Pure-tone frequency difference limens (FDLs) have been shown to vary in the vicinity of spontaneous otoacoustic emissions (SOAEs). As lower FDLs have been observed near SOAEs when measured ipsi- and contralaterally to the emission ear, it has been proposed that prolonged ongoing stimulation of nerve cells tuned to the SOAE frequency could lead to a central oversensitivity to that frequency, hence a better frequency-discrimination ability. However, it is also known that tones close in frequency to an SOAE can "entrain" the emission to oscillate at their own frequency. This may instead explain the variations in FDL near SOAE frequencies as arising from peripheral interactions between SOAEs and external tones in the cochlea. To test these two hypotheses, SOAE entrainment patterns and FDLs were recorded in seven subjects with an ipsilateral SOAE and no neighboring contralateral SOAE. Ipsilateral FDLs were lowest in the SOAE entrainment region and worsened significantly when beating between the external tone and SOAE occurred. FDLs remained unaffected in the non-emission ear and did not alter with continuous ipsilateral or contralateral presentation of a pure tone aimed at emulating an SOAE. These findings suggest a mechanical rather than neural origin for the variations in FDL near SOAE frequencies. PMID:25480062

  3. 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.

  4. Final LDRD report : enhanced spontaneous emission rate in visible III-nitride LEDs using 3D photonic crystal cavities.

    SciTech Connect

    Fischer, Arthur Joseph; Subramania, Ganapathi S.; Coley, Anthony J.; Lee, Yun-Ju; Li, Qiming; Wang, George T.; Luk, Ting Shan; Koleske, Daniel David; Fullmer, Kristine Wanta

    2009-09-01

    The fundamental spontaneous emission rate for a photon source can be modified by placing the emitter inside a periodic dielectric structure allowing the emission to be dramatically enhanced or suppressed depending on the intended application. We have investigated the relatively unexplored realm of interaction between semiconductor emitters and three dimensional photonic crystals in the visible spectrum. Although this interaction has been investigated at longer wavelengths, very little work has been done in the visible spectrum. During the course of this LDRD, we have fabricated TiO{sub 2} logpile photonic crystal structures with the shortest wavelength band gap ever demonstrated. A variety of different emitters with emission between 365 nm and 700 nm were incorporated into photonic crystal structures. Time-integrated and time-resolved photoluminescence measurements were performed to measure changes to the spontaneous emission rate. Both enhanced and suppressed emission were demonstrated and attributed to changes to the photonic density of states.

  5. TEMPLATING SPONTANEOUS MOLECULAR CHAIN GROWTH WITH FEEDBACK-CONTROLLED LITHOGRAPHY

    E-print Network

    Shull, Kenneth R.

    with conventional silicon microelectronic technology. This figure is an atomic resolution ultra-high vacuum scanning on silicon surfaces using ultra-high vacuum scanning tunneling microscopy. Although FCL enables unsurpassed by combining FCL with a spontaneous molecular chain growth process. In particular, FCL is used to pattern

  6. Comparison of the classical rate and the Einstein coefficient for spontaneous emission in a light-absorbing cavity

    SciTech Connect

    Datsyuk, Vitaly V.; Juodkazis, Saulius; Misawa, Hiroaki [CREST-JST and Research Institute for Electronic Science, Hokkaido University, N21-W10 CRIS Bldg., Sapporo 001-0021 (Japan)

    2005-08-15

    The rate of spontaneous electromagnetic emission in a cavity is the normalized output radiation rate in the classical electrodynamics and the Einstein A coefficient in a quantum theory. We reveal the difference and similarity between the quantum and classical rates by calculations of the relative output power of the resonant spontaneous electric-dipole emission as a function of light absorption in a high-Q cavity. We show that the relative resonant output power is equal to the relative width of a morphology-dependent resonance in the spectral dependence of the Einstein A coefficient. The validity of the theory is demonstrated by numerical verification of an experimental result on a microsphere.

  7. 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).

  8. 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...

  9. Observation of novel radioactive decay by spontaneous emission of complex nuclei

    SciTech Connect

    Barwick, S.W.

    1986-01-01

    Two years of experimental investigation on the subject of spontaneous emission of intermediate-mass fragments is described in this manuscript. A short introduction on this subject and a historical review are presented in chapter 1. In chapter 2, the author describe the experimental methods which led to the observation of /sup 14/C emission in polycarbonate etched-track detectors from the isotopes /sup 222/Ra, /sup 223/Ra, /sup 224/Ra and /sup 226/Ra at the branching ratios with respect to ..cap alpha..-decay of (3.7 +/- 0.6) x 10/sup -10/, (6.1 +/- 1.0) x 10/sup -10/, (4.3 +/- 1.2) x 10/sup -10/ and (2.9 +/- 1.0) x 10/sup -11/ respectively. Branching ratio limits for heavy-ion emission from /sup 221/Fr, /sup 221/Ra and /sup 225/Ac were determined to be at < 5.0 x 10/sup -14/, < 1.2 x 10/sup -13/ and < 4.0 x 10/sup -13/ respectively for the 90% C.L. The emission of /sup 24/Ne from /sup 232/U at a branching ratio of (2.0 +/- 0.5) x 10/sup -12/ has been discovered using polyethylene terephthalate etched-track plastics. A confirmation of /sup 24/Ne and/or /sup 25/Ne emission from /sup 233/U at a branching ratio of (5.3 +/- 2.3) x 10/sup -13/ is also reported. In chapter 3, three models of intermediate-mass decay are discussed-the analytic superasymmetric fission model, the model by Shi and Swiatecki, and a model based on a square-well + Coulomb potential.

  10. Effect of the counterrotating-wave terms on the spontaneous emission from a multilevel atom

    E-print Network

    Li, Zheng-Hong; Wang, Da-Wei; Zheng, Hang; Zhu, Shi-Yao; Zubairy, M. Suhail

    2009-01-01

    #7;#3;0 2e2 3#7;m2c3#18;0#2;c #8;i#6;p2#6;i#7;d#2; = ? 2#8; 3#7;m2c2#18;0#2;c d#2;#5;j #6;pij#6;2 = ? #5; j#1;i,k gk,ij 2 #2;k , #1;11#2; where #8;= e 2 4#7;c#3;0 is the fine structure constant. In the last step, we changed the integration...Effect of the counterrotating-wave terms on the spontaneous emission from a multilevel atom Zheng-Hong Li,1 Da-Wei Wang,2 Hang Zheng,3 Shi-Yao Zhu,1,2 and M. Suhail Zubairy4 1Department of Physics, Hong Kong Baptist University, Hong Kong, China 2...

  11. Proton-transfer laser: gain spectrum and amplification of spontaneous emission of 3-hydroxyflavone

    SciTech Connect

    Chou, P.; McMorrow, D.; Aartsma, T.J.; Kasha, M.

    1984-09-27

    The efficient generations of amplified spontaneous emission (ASE) in 3-hydroxyflavone in methylcyclohexane and p-dioxane solutions at 293 K is reported. This application of excited-state proton-transfer tautomerization approaches an ideal four-level laser system involving four different molecular electronic species in separate electronic states and constitutes a photoinduced chemical laser. The gain coefficient for the ASE (530 nm) of 3-hydroxyflavone in methylcyclohexane (293 K) is calculated to be 10-15. Under similar conditions in our apparatus, the gain coefficient is observed to be in the range 7-9 for a proprietary coumarin laser dye (Molectron 70371-4 C485) and for rhodamine-6G. The tunable range for 3-hydroxyflavone is observed to be 518-545 nm. The peak laser power is comparable with that observed for the coumarin dye.

  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. Analysis of the outlook for using narrow-band spontaneous emission sources for atmospheric air purification

    SciTech Connect

    Boyarchuk, K A; Karelin, A V; Shirokov, R V [Institute of Earth Magnetism, Ionosphere and Propagation of Radio waves, Russian Academy of Sciences, Moscow (Russian Federation)

    2003-12-31

    The outlook for using narrow-band spontaneous emission sources for purification of smoke gases from sulphur and nitrogen oxides is demonstrated by calculations based on a nonstationary kinetic model of the N{sub 2} - O{sub 2} - H{sub 2}O - CO{sub 2} - SO{sub 2} mixture. The dependences of the mixture purification efficiency on the UV source power at different wavelengths, the exposure time, and the mixture temperature are calculated. It is shown that the radiation sources proposed in the paper will provide better purification of waste gases in the atmosphere. The most promising is a KrCl* lamp emitting an average power of no less than 100 W at 222 nm. (laser applications and other topics in quantum electronics)

  14. High-power thulium-doped all-fibre amplified spontaneous emission sources

    NASA Astrophysics Data System (ADS)

    Jin, Xiaoxi; Wang, Xiong; Xu, Jiangming; Wang, Xiaolin; Zhou, Pu

    2015-04-01

    We demonstrate high-power thulium-doped all-fibre amplified spontaneous emission (ASE) sources operating at ~2 ?m with both broadband and narrowband spectra based on thulium-doped fibre master oscillator power amplifier configuration. The maximum output power of broadband thulium-doped all-fibre ASE source reached 316 W with the spectral full width at half maximum (FWHM) of 24 nm and the slope efficiency of 53%. The maximum output power of 292 W and the FWHM of 1.5 nm were obtained with the slope efficiency of 56% in narrowband thulium-doped all-fibre ASE source. To the best of our knowledge, this is the highest output power of both broadband and narrowband all-fibre ASE sources operating at 2 ?m. Output power could be further enhanced via increasing pump power and/or employing better cooling management.

  15. 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.

  16. Influence of the neodymium glass parameters on the amplified spontaneous emission in slab amplifier

    NASA Astrophysics Data System (ADS)

    Wang, Bingyan; Zhang, Junyong; Zhang, Yanli; Wang, Li; Zhu, Jianqiang

    2015-02-01

    Amplified spontaneous emission (ASE) causes the decrease of the inverted population density and the nonuniformity of gain in slab amplifier for high power laser systems. In this paper, a three dimension model, based on the data in SG-II, in which the residual reflection in the cladding and the ASE process are taken into consideration, is built to analyze the space distribution and time evolution of small signal gain coefficient using Monte Carlo algorithm and ray tracing. This model has been verified by comparing with the experimental data. The traverse size of slab is 68.2cm×36.3cm, which is usually decided by the clear aperture and the manufacture. By means of the model, the impact of thickness, residual reflectivity and the stimulated cross section of neodymium glass to the ASE are analyzed in detail.

  17. Analysis of self-amplified spontaneous emission free-electron laser using Lienard-Wiechert fields

    NASA Astrophysics Data System (ADS)

    Kia, M. R.; Maraghechi, B.

    2012-04-01

    Dynamical equations of electrons in an electron beam with finite length under the influence of a planar wiggler magnetic field and the Lienard-Wiechert fields of other electrons are derived and solved numerically. The analysis is applicable to self-amplified spontaneous emission free-electron laser for which no initial seed radiation is required. By assuming a monoenergetic and filamentary electron beam, thermal effects are neglected and electrons are injected with zero average transverse distance from the wiggler axis. The formalism is based on the retardation effects; therefore, slippage is naturally embedded in the analysis. It was found that energy, number density, and two-particle correlation for the electron beam are modulated by the radiation wavelength which indicates bunching. Spatial, temporal, and angular characteristics of electromagnetic radiation power are also studied.

  18. REVIEWS OF TOPICAL PROBLEMS: Spontaneous and stimulated emission induced by an electron, electron bunch, and electron beam in a plasma

    NASA Astrophysics Data System (ADS)

    Kuzelev, M. V.; Rukhadze, A. A.

    2008-10-01

    Two fundamental mechanisms — the Cherenkov effect and anomalous Doppler effect — underlying the emission by an electron during its superluminal motion in medium are considered. Cherenkov emission induced by a single electron and a small electron bunch is spontaneous. In the course of spontaneous Cherenkov emission, the translational motion of an electron is slowed down and the radiation energy grows linearly with time. As the number of radiating electrons increases, Cherenkov emission becomes stimulated. Stimulated Cherenkov emission represents a resonance beam instability. This emission process is accompanied by longitudinal electron bunching in the beam or by the breaking of an electron bunch into smaller bunches, in which case the radiation energy grows exponentially with time. In terms of the longitudinal size Le of the electron bunch there is a transition region ? < Le < ??0-1 between the spontaneous and stimulated Cherenkov effects, where ? is the average radiation wavelength, and ?0 is the dimensionless (in units of the radiation frequency) growth rate of the Cherenkov beam instability. The range to the left of this region is dominated by spontaneous emission, whereas the range to the right of this region is dominated by stimulated emission. In contrast to the Vavilov-Cherenkov effect, the anomalous Doppler effect should always (even for a single electron) be considered as stimulated, because it can only be explained by accounting for the reverse action of the radiation field on the moving electron. During stimulated emission in conditions where anomalous Doppler effect shows itself, an electron is slowed down and spins up; in this case, the radiation energy grows exponentially with time.

  19. Gravity Wave Emission by Spontaneous Imbalance of Baroclinic Waves in the Continuously Stratified Rotating Annulus

    NASA Astrophysics Data System (ADS)

    Borchert, Sebastian; Achatz, Ulrich; Rieper, Felix; Fruman, Mark

    2013-04-01

    We use a numerical model of the classic differentially heated rotating annulus experiment to study the spontaneous emission of gravity waves (GWs) from jet stream imbalances, which is a major source of these waves in the atmosphere for which no satisfactory parameterization exists. Atmospheric observations are the main tool for the testing and verification of theoretical concepts but have their limitations. Given their specific potential for yielding reproducible data and for studying process dependence on external system parameters, laboratory experiments are an invaluable complementary tool. Experiments with a rotating annulus exhibiting a jet modulated by large-scale waves due to baroclinic instability have already been used to study GWs: Williams et al (2008) observed spontaneously emitted interfacial GWs in a two-layer flow, and Jacoby et al (2011) detected GWs emitted from boundary-layer instabilities in a differentially heated rotating annulus. Employing a finite-volume code for the numerical simulation of a continuously stratified liquid in a differentially heated rotating annulus, we here investigate the GWs in a wide and shallow annulus with relatively large temperature difference between inner and outer cylinder walls. In this atmosphere-like regime where the Brunt-Vaisala frequency is larger than the inertial frequency, various analyses suggest a distinct gravity wave activity. To identify regions of GW emission we decompose the flow into the geostrophic and ageostrophic part through the inversion of the quasi-geostrophic potential vorticity (e.g. Verkley, 2009). The analysis of the geostrophic sources of the ageostrophic flow indicates that, in addition to boundary layer instabilities, spontaneous imbalance in the jet region acts as an important source mechanism. Jacoby, T. N. L., Read, P. L., Williams, P. D. and Young, R. M. B., 2011: Generation of inertia-gravity waves in the rotating thermal annulus by a localised boundary layer instability. Geophys. Astrophys. Fluid Dyn., 105, 161-181. Doi:10.1080/03091929.2011.560151 Verkley, W.T.M., 2009: A balanced approximation of the one-layer shallow-water equations on a sphere. J. Atmos. Sci., 66, 1735-1748. Doi:10.1175/2008JAS2837.1 Williams, P. D., Haine, T. W. N. and Read, P. L., 2008: Inertia-gravity waves emitted from balanced flow: observations, properties, and consequences. J. Atmos. Sci., 65, 3543-3556. Doi:10.1175/2008JAS2480.1

  20. 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

  1. 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 ...

  2. Towards the two-dimensional imaging of spontaneous ultra-weak photon emission from microbial, plant and animal cells.

    PubMed

    Prasad, Ankush; Pospíšil, Pavel

    2013-01-01

    Two-dimensional imaging of spontaneous ultra-weak photon emission was measured in the yeast cells, Arabidopsis plant and the human hand using highly sensitive charge coupled device (CCD) camera. For the first time, the detail analysis of measuring parameters such as accumulation time and binning is provided with the aim to achieve two-dimensional images of spontaneous ultra-weak photon emission of good quality. We present data showing that using a hardware binning with binning factor 4 × 4, the accumulation time decreases in the following order: yeast cells (30?min) > the human hand (20?min) > Arabidopsis plant (10?min). Analysis of measuring parameters provides a detailed description of standard condition to be used for two-dimensional spontaneous ultra-weak photon imaging in microbes, plants and animals. Thus, CCD imaging can be employed as a unique tool to examine the oxidative state of the living organism with the application in microbiological, plant and medical research. PMID:23386970

  3. Towards the two-dimensional imaging of spontaneous ultra-weak photon emission from microbial, plant and animal cells

    PubMed Central

    Prasad, Ankush; Pospíšil, Pavel

    2013-01-01

    Two-dimensional imaging of spontaneous ultra-weak photon emission was measured in the yeast cells, Arabidopsis plant and the human hand using highly sensitive charge coupled device (CCD) camera. For the first time, the detail analysis of measuring parameters such as accumulation time and binning is provided with the aim to achieve two-dimensional images of spontaneous ultra-weak photon emission of good quality. We present data showing that using a hardware binning with binning factor 4 × 4, the accumulation time decreases in the following order: yeast cells (30?min) > the human hand (20?min) > Arabidopsis plant (10?min). Analysis of measuring parameters provides a detailed description of standard condition to be used for two-dimensional spontaneous ultra-weak photon imaging in microbes, plants and animals. Thus, CCD imaging can be employed as a unique tool to examine the oxidative state of the living organism with the application in microbiological, plant and medical research. PMID:23386970

  4. 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...

  5. Spontaneous emission from a two-level atom tunneling in a double-well potential Daniel Braun and John Martin

    E-print Network

    Giraud, Olivier

    Spontaneous emission from a two-level atom tunneling in a double-well potential Daniel Braun-level atom in a double-well potential coupled to a continuum of electromagnetic modes black-body radiation in a double-well potential and to tunnel coherently between the two wells with tunnel- ing frequency

  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. BAPTA induces frequency shifts in vivo of spontaneous otoacoustic emissions of the bobtail lizard.

    PubMed

    Manley, Geoffrey A; Kirk, Desmond L

    2005-01-01

    Spontaneous otoacoustic emissions (SOAEs) are indicators of active processes in the inner ear and are found in all classes of land vertebrates. In the Australian bobtail lizard, earlier work showed that otoacoustic emissions are generated by an active motility process in the hair-cell bundle. This is likely to be driven by calcium-sensitive mechanisms implicated in other non-mammalian hair cell systems. If so, it should be fundamentally influenced by the extracellular calcium concentration. In in vitro studies, the rate of force generation in hair cell stereovilli is linked to the extracellular calcium concentration. In such preparations, low-calcium solutions, buffered by the calcium chelator BAPTA, were reported to change the frequency of hair cell bundle oscillations. In the present study, BAPTA was iontophoresed into the endolymph of the bobtail skink in vivo, and SOAEs were monitored. Application of BAPTA resulted in a prolonged downward shift in the frequency of individual SOAE spectral peaks. Recovery took more than 1 h, consistent with a slow clearance of BAPTA from endolymph. SOAE peak amplitudes were most often enhanced, suggesting there was no functional disruption of tip links. The direction and degree of frequency shifts were consistent with in vitro and in vivo data showing the effects of changing calcium concentrations in the endolymph directly. PMID:15925861

  8. Mammalian spontaneous otoacoustic emissions are amplitude-stabilized cochlear standing waves.

    PubMed

    Shera, Christopher A

    2003-07-01

    Mammalian spontaneous otoacoustic emissions (SOAEs) have been suggested to arise by three different mechanisms. The local-oscillator model, dating back to the work of Thomas Gold, supposes that SOAEs arise through the local, autonomous oscillation of some cellular constituent of the organ of Corti (e.g., the "active process" underlying the cochlear amplifier). Two other models, by contrast, both suppose that SOAEs are a global collective phenomenon--cochlear standing waves created by multiple internal reflection--but differ on the nature of the proposed power source: Whereas the "passive" standing-wave model supposes that SOAEs are biological noise, passively amplified by cochlear standing-wave resonances acting as narrow-band nonlinear filters, the "active" standing-wave model supposes that standing-wave amplitudes are actively maintained by coherent wave amplification within the cochlea. Quantitative tests of key predictions that distinguish the local-oscillator and global standing-wave models are presented and shown to support the global standing-wave model. In addition to predicting the existence of multiple emissions with a characteristic minimum frequency spacing, the global standing-wave model accurately predicts the mean value of this spacing, its standard deviation, and its power-law dependence on SOAE frequency. Furthermore, the global standing-wave model accounts for the magnitude, sign, and frequency dependence of changes in SOAE frequency that result from modulations in middle-ear stiffness. Although some of these SOAE characteristics may be replicable through artful ad hoc adjustment of local-oscillator models, they all arise quite naturally in the standing-wave framework. Finally, the statistics of SOAE time waveforms demonstrate that SOAEs are coherent, amplitude-stabilized signals, as predicted by the active standing-wave model. Taken together, the results imply that SOAEs are amplitude-stabilized standing waves produced by the cochlea acting as a biological, hydromechanical analog of a laser oscillator. Contrary to recent claims, spontaneous emission of sound from the ear does not require the autonomous mechanical oscillation of its cellular constituents. PMID:12880039

  9. Loss of the Tectorial Membrane Protein CEACAM16 Enhances Spontaneous, Stimulus-Frequency, and Transiently Evoked Otoacoustic Emissions

    PubMed Central

    Goodyear, Richard J.; Homma, Kazuaki; Legan, P. Kevin; Korchagina, Julia; Naskar, Souvik; Siegel, Jonathan H.; Dallos, Peter; Zheng, Jing

    2014-01-01

    ?-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

  10. Realization of dynamic thermal emission control.

    PubMed

    Inoue, Takuya; De Zoysa, Menaka; Asano, Takashi; Noda, Susumu

    2014-10-01

    Thermal emission in the infrared range is important in various fields of research, including chemistry, medicine and atmospheric science. Recently, the possibility of controlling thermal emission based on wavelength-scale optical structures has been intensively investigated with a view towards a new generation of thermal emission devices. However, all demonstrations so far have involved the 'static' control of thermal emission; high-speed modulation of thermal emission has proved difficult to achieve because the intensity of thermal emission from an object is usually determined by its temperature, and the frequency of temperature modulation is limited to 10-100 Hz even when the thermal mass of the object is small. Here, we experimentally demonstrate the dynamic control of thermal emission via the control of emissivity (absorptivity), at a speed four orders of magnitude faster than is possible using the conventional temperature-modulation method. Our approach is based on the dynamic control of intersubband absorption in n-type quantum wells, which is enhanced by an optical resonant mode in a photonic crystal slab. The extraction of electrical carriers from the quantum wells leads to an immediate change in emissivity from 0.74 to 0.24 at the resonant wavelength while maintaining much lower emissivity at all other wavelengths. PMID:25064232

  11. Realization of dynamic thermal emission control

    NASA Astrophysics Data System (ADS)

    Inoue, Takuya; Zoysa, Menaka De; Asano, Takashi; Noda, Susumu

    2014-10-01

    Thermal emission in the infrared range is important in various fields of research, including chemistry, medicine and atmospheric science. Recently, the possibility of controlling thermal emission based on wavelength-scale optical structures has been intensively investigated with a view towards a new generation of thermal emission devices. However, all demonstrations so far have involved the ‘static’ control of thermal emission; high-speed modulation of thermal emission has proved difficult to achieve because the intensity of thermal emission from an object is usually determined by its temperature, and the frequency of temperature modulation is limited to 10–100 Hz even when the thermal mass of the object is small. Here, we experimentally demonstrate the dynamic control of thermal emission via the control of emissivity (absorptivity), at a speed four orders of magnitude faster than is possible using the conventional temperature-modulation method. Our approach is based on the dynamic control of intersubband absorption in n-type quantum wells, which is enhanced by an optical resonant mode in a photonic crystal slab. The extraction of electrical carriers from the quantum wells leads to an immediate change in emissivity from 0.74 to 0.24 at the resonant wavelength while maintaining much lower emissivity at all other wavelengths.

  12. 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.

  13. 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

  14. Examination of bleederless ventilation practices for spontaneous combustion control in US coal mines

    SciTech Connect

    Organiscak, J.A.; Smith, A.C.; Diamond, W.P.; Mucho, T.P. [Bureau of Mines, Pittsburgh, PA (United States)

    1995-12-31

    The U.S. Bureau of Mines examined bleederless ventilation practices to evaluate their use as a spontaneous combustion control measure in U.S. coal mines. Results indicate that restricting airflow into mined-out areas (bleederless ventilation) is recognized worldwide as a spontaneous combustion control measure. However, ventilation practices commonly used to limit airflow to mined-out areas are not easily applicable to United States mining conditions, systems, experience and regulations. The types of bleederless ventilation systems used throughout the world and the spontaneous combustion risks associated with these systems are discussed. Primary design considerations for bleederless ventilation consist of the interaction of ventilation practices, methane drainage, ground control, seal construction and mine monitoring. Technological improvements needed for U.S. application of bleederless ventilation are also discussed.

  15. Saturation and Refraction in Amplified Spontaneous Emission X-Ray Lasers

    NASA Astrophysics Data System (ADS)

    Pert, G. J.

    2002-11-01

    Recent developments in X-ray design have been based on plasmas pumped by very short (psec) pulses. In these systems the gain is both short lived and strong. Efficient operation requires that the pump pulse be applied in a travelling wave mode whereby the gain and output pulses are in synchronism. Under these conditions large overall gain lengths are readily achieved, and the output is rapidly saturated. Saturation by reducing the local emission rate leads to non-linear coupling if more than beam is active. If the gain pulse has a short lifetime, the backward travelling pulse is weak and has a negligible effect. However as the gain lifetime increases, the backward wave becomes stronger, with a larger gain-length and may eventually saturate. In this case the backward saturation will reduce the gain seen by the forward wave, and the forward wave output will be reduced. In principal this may lead to oscillations in the output signal if the gain duration is sufficiently long. In the limiting case when the gain duration is very long, the output relaxes to the familiar steady state solution representing symmetric bi-directional output. Refraction is endemic in collisionally pumped X-ray lasers, whereby the X-ray beam is deflected out of the gain region. Experimental systems use a pre-pulse generated plasma to provide a low density gradient plasma in which the laser may develop without suffering severe refraction. The refraction within the gain zone therefore defines a characteristic length, the refraction length over which amplification can occur. If the system is saturated over the refraction length, the resultant reduction in spontaneous emission at the head of the first refraction zone will reduce the input into the second and diminish its output. As a result a plot of output as a function of length may show characteristic overshoot/undershoot behaviour.

  16. Measurements of amplified spontaneous emission in ?-conjugated polymer films with different morphology

    NASA Astrophysics Data System (ADS)

    Wang, Yuchen; Yang, Xiao; Wang, Ruizhi; Sheng, Chuanxiang

    2014-09-01

    ?-conjugated polymers (PCPs) are attractive candidates as gain media in laser applications due to their high photoluminescence quantum efficiency in broad spectral range. However, the self-absorption of long-lived excited states was considered to be a limitation for achieving more effective organic lasers. Moreover, the morphology of films is found to be crucial to their optical and electrical properties recently. In this work, we studied amplified spontaneous emission (ASE) of a typical PCP, namely, Poly [2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene] (MEH-PPV) films with a 10 ns 532 nm pulse laser focused by a cylindrical lens for obtaining an excitation area in the form of a 100 ?m wide and 1 cm long stripe. In an as cast MEH-PPV film, the thresholds increase with the temperatures increase due to the thermal torsion and vibration mode shorten the conjugation chain. On the other hand, a MEH-PPV film which is annealed in Nitrogen at 350 K of half hour, the ASE is not observed at both 300 K and 77 K, for annealing will form ?- stacks which increase the interchain interaction. Further analysis suggests that interchain excimers instead of intrachain excitons may be more primary to optical properties in annealed MEH-PPV film. Our measurements suggest that the morphology of the film instead of long lived photoexcitation with lifetime sensitive to the temperature is more crucial to threshold of ASE, as well as, to PCPs lasers.

  17. Nonequilibrium quantum fluctuations of a dispersive medium: Spontaneous emission, photon statistics, entropy generation, and stochastic motion

    NASA Astrophysics Data System (ADS)

    Maghrebi, Mohammad F.; Jaffe, Robert L.; Kardar, Mehran

    2014-07-01

    We study the implications of quantum fluctuations of a dispersive medium, under steady rotation, either in or out of thermal equilibrium with its environment. A rotating object exhibits a quantum instability by dissipating its mechanical motion via spontaneous emission of photons, as well as internal heat generation. Universal relations are derived for the radiated energy and angular momentum as trace formulas involving the object's scattering matrix. We also compute the quantum noise by deriving the full statistics of the radiated photons out of thermal and/or dynamic equilibrium. The (entanglement) entropy generation is quantified and the total entropy is shown to be always increasing. Furthermore, we derive a Fokker-Planck equation governing the stochastic angular motion resulting from the fluctuating backreaction frictional torque. As a result, we find a quantum limit on the uncertainty of the object's angular velocity in steady rotation. Finally, we show in some detail that a rotating object drags nearby objects, making them spin parallel to its axis of rotation. A scalar toy model is introduced to simplify the technicalities and ease the conceptual complexities and then a detailed discussion of quantum electrodynamics is presented.

  18. Purified self-amplified spontaneous emission free-electron lasers with slippage-boosted filtering

    NASA Astrophysics Data System (ADS)

    Xiang, Dao; Ding, Yuantao; Huang, Zhirong; Deng, Haixiao

    2013-01-01

    We propose a simple method to significantly enhance the temporal coherence and spectral brightness of a self-amplified spontaneous emission (SASE) free-electron laser (FEL). In this purified SASE (pSASE) FEL, a few undulator sections (called slippage-boosted sections) resonant at a subharmonic of the FEL radiation are used in the middle stage of the exponential growth regime to amplify the radiation while simultaneously reducing the FEL bandwidth. In this slippage-boosted section, the average longitudinal velocity of electrons is reduced, which effectively increases the FEL slippage length that allows the radiation fields initially far apart to create a phase relation, leading to n times increase in FEL cooperation length, where n is the ratio of the resonant wavelength of the slippage-boosted section to that of the original FEL radiation. The purified radiation, as a seed with improved temporal coherence, is further amplified to saturation in the undulator sections tuned to the FEL wavelength. Using the linac coherent light source II (LCLS-II) parameters as an example, we show that with the proposed configuration the temporal coherence and spectral brightness of a SASE FEL can be significantly enhanced. This scheme may be applied to many SASE FEL light sources to enhance the FEL performance.

  19. 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.

  20. Statistical analysis of the chaotic optical field from a self-amplified spontaneous-emission free-electron laser

    NASA Astrophysics Data System (ADS)

    Krinsky, S.; Li, Y.

    2006-06-01

    We use Rice’s theory of shot noise random processes to provide a statistical analysis of the evolution of the amplitude and phase of the chaotic optical field from a high-gain, self-amplified, spontaneous-emission (SASE) free-electron laser. The theoretical framework developed is compared with recent frequency-resolved optical-gating measurements of the SASE output at the LEUTL facility at Argonne National Laboratory.

  1. 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.

  2. A novel, simple and efficient dye laser with low amplified spontaneous emission background for analytical fluorescence and ionization spectroscopy

    SciTech Connect

    Matveev, Oleg I.; Omenetto, Nicolo' [EC, Joint Research Centre, Environment Institute, 21020 Ispra, Varese (Italy)

    1995-04-01

    A new, simple, compact and efficient, grazing- incidence type of dye laser is suggested which has a low level of Amplified Spontaneous Emission. By using a Coumarin dye (LD 5000) pumped with a 20 mJ XeCl excimer laser, and a diffraction grating with 3000 grooves/mm, an efficiency of 11%, a spectral bandwidth of 0.6 cm{sup -1} and a tuning range from 458 to 517 nm have been obtained.

  3. 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

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

    E-print Network

    Kieras, Jessica E

    2013-02-22

    and their parents. Regulation of emotion was measured by observational coding of children's reactions to receiving gifts of varied desirability. Effortful control functions included slowing down motor activity, and suppressing/initiating motor response to signal. A...

  5. Variable emissivity laser thermal control system

    DOEpatents

    Milner, Joseph R. (Livermore, CA)

    1994-01-01

    A laser thermal control system for a metal vapor laser maintains the wall mperature of the laser at a desired level by changing the effective emissivity of the water cooling jacket. This capability increases the overall efficiency of the laser.

  6. Controlling carbon emissions in China

    Microsoft Academic Search

    RICHARD F. GARBACCIO; MUN S. HO; DALE W. JORGENSON

    1999-01-01

    We examine the use of carbon taxes to reduce emissions of CO2 in China. To do so, we develop a dynamic computable general equilibrium (CGE) model of the Chinese economy. In addition to accounting for the effects of population growth, capital accumulation, technological change, and changing patterns of demand, we also incorporate into our model elements of the dual nature

  7. 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

  8. Io control of Jovian radio emission

    NASA Technical Reports Server (NTRS)

    Desch, M. D.

    1980-01-01

    The possibility of Io controlling Jovian decametric radio emission, particularly in the region below 22 MHz, is discussed. Results of a two-year survey at 26.3 at 26.3 MHz are presented which demonstrate the control of Io over a high-intensity storm component of the radio emission and the independence of a weak radio component from the phase of Io, as was observed at lower frequencies. It is thus hypothesized that Io control is a flux-dependent rather than a frequency-dependent phenomenon, and results of analyses at 18 and 10 MHz which support this hypothesis are presented. The apparent correlation between frequency and Io control is thus shown to result from a selection effect due to the increase of non-Io emission with decreasing frequency and relative antenna detection threshold. This result implies a contiguous Io-controlled source region extending out several Jovian radii along the Io flux tube.

  9. 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.

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

    NASA Astrophysics Data System (ADS)

    Petrillo, V.; Rossi, A. R.; Serafini, L.

    2013-12-01

    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.

  11. Cavity-enhanced single photon emission from site-controlled In(Ga)As quantum dots fabricated using nanoimprint lithography

    SciTech Connect

    Tommila, J.; Hakkarainen, T. V.; Schramm, A., E-mail: andreas.schramm@tut.fi; Guina, M. [Optoelectronics Research Centre, Tampere University of Technology, P.O. Box 692, FIN-33101 Tampere (Finland); Belykh, V. V.; Sibeldin, N. N. [P.N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow 119991 (Russian Federation); Heinonen, E. [Center of Microscopy and Nanotechnology, University of Oulu, P.O. Box 7150, FIN-90014 Oulu (Finland)

    2014-05-26

    We report on the emission dynamics of single In(Ga)As quantum dots formed in etched GaAs pits and integrated into micropillar cavities. The site-controlled quantum dots were fabricated by molecular beam epitaxy on nanoimprint lithography patterned GaAs(001) surfaces. Triggered single photon emission confirmed by photon autocorrelation measurements is demonstrated. Time-resolved photoluminescence experiments clearly show an effect of the cavity on the spontaneous emission rate of the quantum dot.

  12. Cavity-enhanced single photon emission from site-controlled In(Ga)As quantum dots fabricated using nanoimprint lithography

    NASA Astrophysics Data System (ADS)

    Tommila, J.; Belykh, V. V.; Hakkarainen, T. V.; Heinonen, E.; Sibeldin, N. N.; Schramm, A.; Guina, M.

    2014-05-01

    We report on the emission dynamics of single In(Ga)As quantum dots formed in etched GaAs pits and integrated into micropillar cavities. The site-controlled quantum dots were fabricated by molecular beam epitaxy on nanoimprint lithography patterned GaAs(001) surfaces. Triggered single photon emission confirmed by photon autocorrelation measurements is demonstrated. Time-resolved photoluminescence experiments clearly show an effect of the cavity on the spontaneous emission rate of the quantum dot.

  13. CONTROL OF AIR EMISSIONS FROM SUPERFUND SITES

    EPA Science Inventory

    This handbook is an easy-to-use tool for decision makers to evaluate emission control devices for use with Superfund remediation actions. t will assist in the selection of cost-effective control options. t is intended for use by engineers and scientists involved in preparing reme...

  14. "Spontaneous" transfer of stimulus control from tact to mand contingencies.

    PubMed

    Sigafoos, J; Reichle, J; Doss, S; Hall, K; Pettitt, L

    1990-01-01

    An important issue in teaching verbal behavior to persons with severe handicaps is the transfer of stimulus control from tact (e.g., naming) to mand (e.g., requesting) relationships. Previous research has shown that topographies taught as tacts frequently fail to appear as mands unless transfer between these two response classes is explicitly programmed. Procedures promoting this transfer would provide a necessary instructional tool. Transfer from tact to mand contingencies was investigated in two adults with severe mental retardation. Correct pointing responses to line drawing symbols depicting the utensils required to access previously requested food (beverage) items were assessed prior to and following tact intervention. Mands for two of three utensils emerged following tact intervention. The results suggest transfer from tact variables to the conditioned establishing operation may be facilitated by the prior development of a minimal mand repertoire. PMID:2142795

  15. POLLUTION CONTROL PRACTICES: COST FOR CONTROL OF SO2 EMISSIONS

    EPA Science Inventory

    The paper gives results of a study (part of a multiphased EPA study of the acid rain problem) the objectives of which were to (1) identify and characterize existing industrial sources of SO2 emissions, (2) identify the control techniques that can be used to reduce SO2 emissions f...

  16. 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

  17. 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.

  18. Controlling the emission from semiconductor quantum dots using ultra-small tunable optical microcavities

    NASA Astrophysics Data System (ADS)

    Di, Ziyun; Jones, Helene V.; Dolan, Philip R.; Fairclough, Simon M.; Wincott, Matthew B.; Fill, Johnny; Hughes, Gareth M.; Smith, Jason M.

    2012-10-01

    We report the control of spontaneous emission from CdSe/ZnS core-shell quantum dots coupled to novel open-access optical microcavities. The cavities are fabricated by focused ion beam milling and provide mode volumes less than a cubic micrometre. The quantum dot emission spectrum, spatial modes and lifetime are all modified substantially by the presence of the cavity, and can be tuned by actively varying the cavity length. An increase in emission rate of 75% is achieved at room temperature, attributed to the Purcell effect in the ‘bad emitter’ regime. We demonstrate a high degree of control over the emission from the dots, including near single-mode operation and the ability to detect strong emission from individual nanocrystals.

  19. Advanced CIDI Emission Control System Development

    SciTech Connect

    Lambert, Christine

    2006-05-31

    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 gasoline engines shown in Europe. Selective Catalytic Reduction (SCR) with aqueous urea as the NOx reductant and a Catalyzed Diesel Particulate Filter (CDPF) were chosen as the primary emission control system components. The program expected to demonstrate more than 90% durable reduction in particulate matter (PM) and NOx emissions on a light-duty truck application, based on the FTP-75 drive cycle. Very low sulfur diesel fuel (<15 ppm-wt) enabled lower PM emissions, reduced fuel economy penalty due to the emission control system and improved long-term system durability. Significant progress was made toward a durable system to meet Tier 2 Bin 5 emission standards on a 6000 lbs light-duty truck. A 40% reduction in engine-out NOx emissions was achieved with a mid-size prototype diesel engine through engine recalibration and increased exhaust gas recirculation. Use of a rapid warm-up strategy and urea SCR provided over 90% further NOx reduction while the CDPF reduced tailpipe PM to gasoline vehicle levels. Development work was conducted to separately improve urea SCR and CDPF system durability, as well as improved oxidation catalyst function. Exhaust gas NOx and ammonia sensors were also developed further. While the final emission control system did not meet Tier 2 Bin 5 NOx after 120k mi of aging on the dynamometer, it did meet the standards for HC, NMOG, and PM, and an improved SCR catalyst was shown to have potential to meet the NOx standard, assuming the DOC durability could be improved further. Models of DOC and SCR function were developed to guide the study of several key design factors for SCR systems and aid in the development of urea control strategy for maximum NOx reduction with minimum NH3 slip. A durable co-fueling system was successfully built and tested, with the help of service station nozzle and dispenser manufacturers, for simultaneous delivery of diesel fuel and aqueous urea to the vehicle. The business case for an aqueous urea infrastructure in the US for light-duty vehicles was explored.

  20. 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.

  1. Spontaneous neuronal activity predicts intersubject variations in executive control of attention.

    PubMed

    Xu, J; Rees, G; Yin, X; Song, C; Han, Y; Ge, H; Pang, Z; Xu, W; Tang, Y; Friston, K; Liu, S

    2014-03-28

    Executive control of attention regulates our thoughts, emotion and behavior. Individual differences in executive control are associated with task-related differences in brain activity. But it is unknown whether attentional differences depend on endogenous (resting state) brain activity and to what extent regional fluctuations and functional connectivity contribute to individual variations in executive control processing. Here, we explored the potential contribution of intrinsic brain activity to executive control by using resting-state functional magnetic resonance imaging (fMRI). Using the amplitude of low-frequency fluctuations (ALFF) as an index of spontaneous brain activity, we found that ALFF in the right precuneus (PCUN) and the medial part of left superior frontal gyrus (msFC) was significantly correlated with the efficiency of executive control processing. Crucially, the strengths of functional connectivity between the right PCUN/left msFC and distributed brain regions, including the left fusiform gyrus, right inferior frontal gyrus, left superior frontal gyrus and right precentral gyrus, were correlated with individual differences in executive performance. Together, the ALFF and functional connectivity accounted for 67% of the variability in behavioral performance. Moreover, the strength of functional connectivity between specific regions could predict more individual variability in executive control performance than regionally specific fluctuations. In conclusion, our findings suggest that spontaneous brain activity may reflect or underpin executive control of attention. It will provide new insights into the origins of inter-individual variability in human executive control processing. PMID:24447598

  2. Amplified spontaneous emission over the XeF(D+X) transition in solid Kr H. Kunttu, W. G. Lawrence, and V. A. Apkariar?)

    E-print Network

    Apkarian, V. Ara

    Amplified spontaneous emission over the XeF(D+X) transition in solid Kr H. Kunttu, W. G. Lawrence of gain on pump intensity and low divergence of the amplified beam are taken as evidence for self to amplified sponta- neous emission (ASE) is observed and used to characterize the gain in the medium.2

  3. Glycol reboiler emissions control process tested

    SciTech Connect

    Not Available

    1993-08-23

    A process that combines proven technologies for maximum control of air pollutants from glycol dehydrators has been developed and undergone a successful prototype field experiment. Radian Corp., Austin, developed the process under contract to the Gas Research Institute (GRI), Chicago, for control of volatile organic compounds (VOCs) including benzene, toluene, ethyl-benzene, and xylene, commonly known as BTEX. The field experiment indicated that 98.4% of BTEX and other VOC emissions generated by the unit were removed.

  4. Variable emissivity laser thermal control system

    DOEpatents

    Milner, J.R.

    1994-10-25

    A laser thermal control system for a metal vapor laser maintains the wall temperature of the laser at a desired level by changing the effective emissivity of the water cooling jacket. This capability increases the overall efficiency of the laser. 8 figs.

  5. 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...

  6. Reversible Polarization Control of Single Photon Emission

    Microsoft Academic Search

    Robert J. Moerland; Tim H. Taminiau; Lukas Novotny; Hulst van Niek F; Laurens Kuipers

    2008-01-01

    We present reversible and a-priori control of the polarization of a photon emitted by a single molecule by introducing a nanoscale metal object in its near field. It is experimentally shown that, with the metal close to the emitter, the polarization ratio of the emission can be varied by a factor of 2. The tunability of polarization decays, when the

  7. Emission control device for carbureted engines

    Microsoft Academic Search

    Thompson

    1991-01-01

    This patent describes an emission control device for use with a carburetor having a base, the base defining therein an opening and a fuel port, the fuel port opening into the opening. It comprises a body member of predetermined thickness and having an upper surface, the body member having at least one through opening, the through opening communicating with the

  8. CONTROLLING ODOROUS EMISSIONS FROM IRON FOUNDRIES

    EPA Science Inventory

    The report discusses the control of odorous emissions from iron foundries. he main process sources of odors in iron foundries are mold and core making, casting, and sand shakeout. he odors are usually caused by chemicals, which may be present as binders and other additives to the...

  9. Combined heat recovery and emission control system

    Microsoft Academic Search

    Haeflich

    1986-01-01

    This patent describes a cogeneration plant having a gas turbine engine, an electric generator driven by the engine and a combined heat recovery and emission control system for the recovery of heat from and reduction of pollutants in the exhaust gas stream from the engine. The combined system consists of: steam boilers, each having at least one bank of steam

  10. FIRED HEATERS: NITROGEN OXIDES EMISSIONS AND CONTROLS

    EPA Science Inventory

    The report gives results of a study of nitrogen oxide (NOx) emissions from, and controls for, fired heaters. The petroleum refining and chemical manufacturing industries account for most of fired-heater energy use with an estimated 4600 fired heaters in operation, in these two in...

  11. WASTE INCINERATION AND EMISSION CONTROL TECHNOLOGIES

    EPA Science Inventory

    The paper gives results of a survey of available waste incineration and emission control technologies in the U.S., Japan, and Western Europe. Increasing concern over landfills as a waste management option and the decreasing availability of sites have focused attention on incinera...

  12. Amplified spontaneous emission from core and shell transitions in CdSe/CdS nanorods fabricated by seeded growth

    NASA Astrophysics Data System (ADS)

    Krahne, Roman; Zavelani-Rossi, Margherita; Lupo, Maria Grazia; Manna, Liberato; Lanzani, Guglielmo

    2011-02-01

    We studied the optical properties of core-shell CdSe/CdS nanorods with various lengths and core diameters that were fabricated by wet chemical synthesis using the seeded growth method. We investigated the optical emission from thin films consisting of dense nanorod arrays, where we observed amplified spontaneous emission from states related either to the CdSe core or to the CdS shell depending on the nanorod's length. The optical gain of the nanorods was studied by transient absorption experiments and we found optical gain for the core and shell states of short rods, whereas for long rods, the optical gain of the core was quenched by defect states and we observed optical gain solely from the states of the shell material.

  13. Systematics of spontaneous emission of intermediate mass fragments from heavy nuclei

    SciTech Connect

    Barwick, S.W.; Price, P.B.; Ravn, H.L.; Hourani, E.; Hussonnois, M.

    1986-07-01

    We have used polycarbonate track-recording films to confirm the rare decay mode of /sup 226/Ra by /sup 14/C emission and to set stringent upper limits on /sup 14/C-emission rates of /sup 221/Fr, /sup 221/Ra, and /sup 225/Ac. The /sup 14/C-emission rate exhibits a pronounced odd-even effect. For Ra isotopes the hindrance factor for odd-even parents relative to even-even parents is at least 10 times higher for /sup 14/C emission than for ..cap alpha.. emission.

  14. Spontaneous Nonneoplastic Lesions in Control Syrian Hamsters in Three 24-month Long-term Carcinogenicity Studies.

    PubMed

    McInnes, Elizabeth F; Ernst, Heinrich; Germann, Paul-Georg

    2015-02-01

    Information about the incidence of spontaneously occurring, nonneoplastic background findings in Syrian hamsters is essential if Syrian hamsters are to be used for toxicity studies. Male and female Syrian hamsters of the strain Han:AURA from the Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM) breeding colony were maintained as control animals for carcinogenicity studies and were examined for the presence of nonneoplastic background findings either when they died or when the study was terminated. The nonneoplastic background lesions observed at an incidence of >50% (high), >25% (moderate), and >10% (low) in either male or female animals or in both sexes in one or more long-term studies are detailed. The results are compared to previous published reports of nonneoplastic, spontaneous background lesions in Syrian hamsters. Background information about the incidence of background lesions in Syrian hamsters on short- and long-term studies is useful to both toxicologists and toxicological pathologists. PMID:24771081

  15. 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.

  16. Photoelectric charging of dust particles: Effect of spontaneous and light induced field emission of electrons

    SciTech Connect

    Sodha, M. S.; Dixit, A. [Disha Institute of Management and Technology, Satya Vihar, Vidhan Sabha-Chandrakhuri Marg, Mandir Hasaud, Raipur, 492101 Chattisgarh (India)

    2009-09-07

    The authors have analyzed the charging of dust particles in a plasma, taking into account the electron/ion currents to the particles, electron/ion generation and recombination, electric field emission, photoelectric emission and photoelectric field emission of electrons under the influence of light irradiation; the irradiance has been assumed to be at a level, which lets the particles retain the negative sign of the charge. Numerical results and discussion conclude the papers.

  17. Photogeneration of charge carrier correlated with amplified spontaneous emission in single crystals of a thiophene/phenylene co-oligomer

    NASA Astrophysics Data System (ADS)

    Saeki, Akinori; Seki, Shu; Shimizu, Yasuhiro; Yamao, Takeshi; Hotta, Shu

    2010-04-01

    Thiophene/phenylene co-oligomers have substantial promise for the use of not only organic electronics but also organic optical devices. However, considerably less is known about the correlation between their optical and optoelectronic properties. We have investigated the charge carrier generation in 1,4-bis(5-phenylthiophen-2-yl)benzene (AC5) single crystals by flash-photolysis time-resolved microwave conductivity (TRMC) and transient absorption spectroscopy (TAS). It was found that the dependence of photocarrier generation efficiency on excitation photon density differed from that of emission efficiency once amplified spontaneous emission (ASE) and resultant spectrally narrowed emission occur upon exposure to 355 nm. In contrast, the dependences of emission and photocarrier generation efficiencies were identical when ASE was not involved at a different excitation wavelength (193 nm). An approximated analytical solution of rate equation considering ASE or singlet-singlet annihilation was applied to the experiments, exhibiting good agreement. On the basis of TRMC, TAS, and extinction coefficient of radical cation assessed by pulse radiolysis, the minimum charge carrier mobility was estimated, without electrodes, to be 0.12 cm2 V-1 s-1. The dynamics of charge carrier and triplet excited state is discussed, accompanying with examination by time-dependent density functional theory. The present work would open the way to a deeper understanding of the fate of excited state in optically robust organic semiconducting crystals.

  18. Photogeneration of charge carrier correlated with amplified spontaneous emission in single crystals of a thiophene/phenylene co-oligomer.

    PubMed

    Saeki, Akinori; Seki, Shu; Shimizu, Yasuhiro; Yamao, Takeshi; Hotta, Shu

    2010-04-01

    Thiophene/phenylene co-oligomers have substantial promise for the use of not only organic electronics but also organic optical devices. However, considerably less is known about the correlation between their optical and optoelectronic properties. We have investigated the charge carrier generation in 1,4-bis(5-phenylthiophen-2-yl)benzene (AC5) single crystals by flash-photolysis time-resolved microwave conductivity (TRMC) and transient absorption spectroscopy (TAS). It was found that the dependence of photocarrier generation efficiency on excitation photon density differed from that of emission efficiency once amplified spontaneous emission (ASE) and resultant spectrally narrowed emission occur upon exposure to 355 nm. In contrast, the dependences of emission and photocarrier generation efficiencies were identical when ASE was not involved at a different excitation wavelength (193 nm). An approximated analytical solution of rate equation considering ASE or singlet-singlet annihilation was applied to the experiments, exhibiting good agreement. On the basis of TRMC, TAS, and extinction coefficient of radical cation assessed by pulse radiolysis, the minimum charge carrier mobility was estimated, without electrodes, to be 0.12 cm(2) V(-1) s(-1). The dynamics of charge carrier and triplet excited state is discussed, accompanying with examination by time-dependent density functional theory. The present work would open the way to a deeper understanding of the fate of excited state in optically robust organic semiconducting crystals. PMID:20387943

  19. Spontaneous and light-induced photon emission from intact brains of chick embryos.

    PubMed

    Zhang, J; Yu, W; Sun, T; Popp, F A

    1997-02-01

    Photon emission (PE) and light-induced photon emission(LPE) of intact brains isolated from chick embryos have been measured by using the single photon counting device. Experimental results showed that the intensity level of photon emission was detected to be higher from intact brain than from the medium in which the brain was immerged during measuring, and the emission intensity was related to the developmental stages, the healthy situation of the measured embryos, and the freshness of isolated brains as well. After white light illumination, a short-life delayed emission from intact brains was observed, and its relaxation behavior followed a hyperbolic rather than an exponential law. According to the hypothesis of biophoton emission originating from a delocalized coherent electromagnetic field and Frohlich' s idea of coherent long-range interactions in biological systems, discussions were made on the significance of photon emission in studying cell communication, biological regulation, living system's relevance to its environment, and also on the relations between the detected photon emission and the coherent electromagnetic field. The detected photon emission should be comprehended in the manner of the interactions between the intrinsic fields within the living systems and their environmental external fields. PMID:18726298

  20. Short test for gasoline powered vehicle emission control

    Microsoft Academic Search

    K. N. Pattas; P. G. Hassiotis

    1987-01-01

    (A short test for the (exhaust gas emission) control has been developed. The proposed method estimates quantitatively the exhaust gas emissions (g\\/km) using only the following variables: a) engine displacement; b) emission at idle; and c) emission at increased idle. This method also permits the evaluation of the spark timing and the (dwell angle influence) on the total emissions of

  1. Process for rejuvenating automobile emission control catalysts

    Microsoft Academic Search

    McArthur

    1976-01-01

    A method is described for the rejuvenation of an automobile emission control catalyst poisoned with compounds of lead and\\/or phosphorus comprising: (1) initially extracting lead sulfate deposits from the catalyst with an aqueous ammonium salt (preferrably ammonium acetate) solution; (2) exposing the catalyst to an atmosphere containing SOâ, or SOâ and air, at 300° to 700°C until other lead compounds

  2. 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.

  3. 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.

  4. Imaging of Ultraweak Spontaneous Photon Emission from Human Body Displaying Diurnal Rhythm

    PubMed Central

    Kobayashi, Masaki; Kikuchi, Daisuke; Okamura, Hitoshi

    2009-01-01

    The human body literally glimmers. The intensity of the light emitted by the body is 1000 times lower than the sensitivity of our naked eyes. Ultraweak photon emission is known as the energy released as light through the changes in energy metabolism. We successfully imaged the diurnal change of this ultraweak photon emission with an improved highly sensitive imaging system using cryogenic charge-coupled device (CCD) camera. We found that the human body directly and rhythmically emits light. The diurnal changes in photon emission might be linked to changes in energy metabolism. PMID:19606225

  5. Nonlinear enhancement of spontaneous biophoton emission of sweet potato by silver nanoparticles.

    PubMed

    Hossu, Marius; Ma, Lun; Chen, Wei

    2010-04-01

    Ultraweak biophoton emission of cutting-injured sweet potato is enhanced by the incubation with Ag nanoparticles in a nonlinear way. The late peak of the emission after the cutting injury is amplified as much as 15 times, while only little amplification was identified for the emission measured immediately after the cutting. The effect requires the presence of nutritive media to support the active metabolic processes and is also affected by the timing of the addition of the Ag nanoparticles. Proposed mechanisms of reactive oxygen species generation and energy resonance transfer are discussed. PMID:20207158

  6. CONTROLLING MULTIPLE EMISSIONS FROM COAL-FIRED POWER PLANTS

    EPA Science Inventory

    The paper presents and analyzes nine existing and novel control technologies designed to achieve multipollutant emissions reductions. It provides an evaluation of multipollutant emission control technologies that are potentially available for coal-fired power plants of 25 MW capa...

  7. Model Identification for Optimal Diesel Emissions Control

    SciTech Connect

    Stevens, Andrew J.; Sun, Yannan; Song, Xiaobo; Parker, Gordon

    2013-06-20

    In this paper we develop a model based con- troller for diesel emission reduction using system identification methods. Specifically, our method minimizes the downstream readings from a production NOx sensor while injecting a minimal amount of urea upstream. Based on the linear quadratic estimator we derive the closed form solution to a cost function that accounts for the case some of the system inputs are not controllable. Our cost function can also be tuned to trade-off between input usage and output optimization. Our approach performs better than a production controller in simulation. Our NOx conversion efficiency was 92.7% while the production controller achieved 92.4%. For NH3 conversion, our efficiency was 98.7% compared to 88.5% for the production controller.

  8. 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.

  9. 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.

  10. 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.

  11. Spectral discrimination between healthy people and cold patients using spontaneous photon emission

    PubMed Central

    Yang, Meina; Pang, Jiangxiang; Liu, Junyan; Liu, Yanli; Fan, Hua; Han, Jinxiang

    2015-01-01

    In this paper, ultra-weak photon emission (UPE) was used to distinguish cold patients from healthy subjects. The UPE intensity of fingertips of two hands from healthy subjects and cold patients was measured using a two-hand UPE detecting system and a group of cut-off filters. We found a significant difference in the maximum spectral peak and photon emission ratio between the filter of 550nm and 495nm, which can be used in distinguish cold patients from healthy people. Methods and results in this work could be useful for developing a new optical diagnostic tool for early disease diagnosis in the future.

  12. PARTICULATE EMISSIONS CONTROL AND ITS IMPACTS ON THE CONTROL OF OTHER AIR POLLUTANT EMISSIONS FROM MUNICIPAL WASTE COMBUSTORS

    EPA Science Inventory

    The paper discusses particulate emissions control and its impacts on the control of other air pollutant emissions from municipal waste combustors (MWCs). Generally, particulate control is an inherent part of the systems used to limit the emissions of these air pollutants. The rel...

  13. 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.

  14. LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Analysis of the outlook for using narrow-band spontaneous emission sources for atmospheric air purification

    Microsoft Academic Search

    K. A. Boyarchuk; A. V. Karelin; R. V. Shirokov

    2003-01-01

    The outlook for using narrow-band spontaneous emission sources for purification of smoke gases from sulphur and nitrogen oxides is demonstrated by calculations based on a nonstationary kinetic model of the N2 --- O2 --- H2O --- CO2 --- SO2 mixture. The dependences of the mixture purification efficiency on the UV source power at different wavelengths, the exposure time, and the

  15. Engine emissions control apparatus and method

    SciTech Connect

    Fosseen, D.

    1990-09-25

    This patent describes an apparatus for reducing the emissions of a diesel engine. It comprises: a hydrous alcohol fuel of between about 33 percent and about 70 percent alcohol by volume and between about 30 percent and 67 percent water by volume; a fuel injector for delivering the hydrous alcohol fuel for combustion in the engine; and means for controlling the delivery of the fuel to the engine in response to operating conditions of the engine, such that the fuel is delivered for combustion only when the engine is being operated to increase the rate of engine revolutions and when the engine is being operated substantially to maintain the rate of engine revolutions.

  16. 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

  17. 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.

  18. Continuous particulate monitoring for emission control

    SciTech Connect

    Bock, A.H. (BHA Group, Inc., Kansas City, MO (United States))

    1993-08-01

    An optical continuous particle monitoring system has been developed to overcome common problems associated with emissions monitoring equipment. Opacity monitors generally use a single- or double-pass system to analyze the presence of dust particles in the flue gas stream. The particles scatter and absorb light as it passes through the stack. As the particle content in the gas stream increases due to bag failure or some other problem, the amount of light that is blocked also increases. The opacity monitor compares the amount of lost light energy to the total energy of the light available and translates the signal to percentage of opacity. Opacity monitors are typically installed to meet the requirements set forth by pollution control agencies. Most opacity monitors are designed to meet all of the requirements of the Environmental Protection Agency (EPA) 40 CFR, Part 60, Appendix B, Performance Specification. The new continuous particle monitor (CPM) increases the accuracy of emission monitoring and overcomes typical problems found in conventional emission monitoring devices. The CPM is an optically based, calibratible, continuous dust monitor that uses a microprocessor, transmitter head, and receiver head. When calibrated with an isokinetic sample, a continuous readout of particulate concentration (in mg/m[sup 3]) in the exhaust gas is provided. The system can be used as a filter bag failure system or a long-term emission trend analyzer. Formal testing was conducted to evaluate the effectiveness of the optically based CPM. The monitor was calibrated using particles of a range of compositions, size distributions, and concentrations. The feasibility of using the instrument to measure particle concentration as low as 10 mg/m[sup 3] was examined.

  19. 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.

  20. 40 CFR 89.110 - Emission control information label.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Emission Standards and Certification...conforms to [model year] U.S. EPA regulations large nonroad compression- ignition engines;” (11) Engines belonging to an...

  1. 40 CFR 89.110 - Emission control information label.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Emission Standards and Certification...conforms to [model year] U.S. EPA regulations large nonroad compression- ignition engines;” (11) Engines belonging to an...

  2. 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...

  3. A prospective controlled trial comparing spontaneous closure and Epifilm® patching in traumatic tympanic membrane perforations.

    PubMed

    Sayin, Ibrahim; Kaya, Kamil Hakan; Ekizo?lu, O?uzhan; Erdim, Ibrahim; Kayhan, Fatma Tülin

    2013-11-01

    The objective was to compare the outcomes of spontaneous closure and hyaluronic acid (HA) ester patching (Epifilm®) in subjects with traumatic tympanic membrane (TM) perforation. This was a prospective, controlled study performed at a tertiary teaching and research hospital. During 6-month period, subjects were divided into spontaneous closure (group A) and HA ester patch-Epifilm® (group B) group. Demographic data, presenting symptoms, closure rate, closure time and audiometric data were evaluated and compared between groups. In total, 155 subjects were evaluated. Group A consisted of 62.6 % (n = 97) of the subjects, whereas group B consisted of 37.4 % (n = 58) of the subjects. Group B had significantly shorter closure times when compared with group A (6.61 ± 4.59 vs. 10.60 ± 5.23 weeks, p = 0.001). When the closure time was evaluated according to perforation size both grade 1 and 2 perforations have significantly shorter closure times when compared with group A (6.33 ± 4.54 vs. 10.80 ± 5.69 weeks, for grade 1 and 6.650 ± 2.07 vs. 10.30 ± 4.32 weeks for grade 2 perforations). Closure rates were not significant between groups (85.6 % for group A and 94.8 % for group B). When the closure rate was evaluated according to perforation size no significant difference exists for grade 1, 2 and 3 perforations between groups. Both air conduction and air-bone gap were significantly improved in both groups. HA ester patch (Epifilm®) is a non-toxic material that can be used in traumatic tympanic membrane perforations. In this study, use of HA ester patching was resulted with earlier closure time but not resulted with higher closure rates. PMID:23292038

  4. Determination of spectral limits imposed by four-wave mixing and amplified spontaneous emission in the 1550?nm region

    NASA Astrophysics Data System (ADS)

    Alvarez-Chavez, J. A.; Sanchez-Lara, R.; Martinez-Piñon, F.; Mendez-Martinez, F.; de la Cruz-May, L.; Perez-Sanchez, G. G.

    2015-04-01

    Dense wavelength division multiplexing (DWDM) systems are normally limited by stimulated Brillouin scattering (SBS), stimulated Raman scattering (SRS), self-phase modulation (SPM), cross-phase modulation (XPM) and four-wave mixing (FWM) besides amplified spontaneous emission (ASE) noise from erbium-doped fiber amplifiers (EDFAs). In this paper, theoretical calculation of FWM-based limits and noise from EDFAs in the 1535–1565?nm region, are reported. Results show that FWM power per channel extended from ?55 to ?20?dBm for dispersion values of 0.0, 0.5, 1.0 and 1.5?ps?(nm?km)?1. In a similar manner, for negative dispersion coefficient (D) values ranging from 0.0 to ?1.5?ps?(nm?km)?1, the FWM power per channel extended from ?60 to ?30?dBm. As for the maximum span length, the calculations demonstrated a rigorous limitation due to noise, suggesting error compensation techniques. A full set of results for the design of multi-span links is included.

  5. Efficiency enhancement in seeded and self-amplified spontaneous emission free-electron lasers by means of a tapered wiggler

    SciTech Connect

    Freund, H. P.; Miner, W. H. Jr. [Science Applications International Corp., 1710 SAIC Drive, McLean, Virginia 22102 (United States)

    2009-06-01

    The enhancement of the efficiency in free-electron lasers (FELs) through the use of a tapered wiggler is well known. The physics of the tapered wiggler interaction has been studied in theory and simulation, and large efficiency enhancements have been observed in the laboratory in oscillators and seeded amplifiers. In this paper, we study the differences in the tapered wiggler interaction between seeded amplifiers and in FELs that start up from noise and grow to saturation in a single pass through the wiggler. This configuration is commonly referred to as self-amplified spontaneous emission (SASE). In comparison with seeded amplifiers, SASE FELs exhibit shot-to-shot fluctuations due to random phase noise in the electron bunches, and our purpose in this paper is to determine the effect of this phase noise on the tapered wiggler interaction. To this end, we study the interaction numerically using the MEDUSA simulation code for seeded and SASE FELs operating in the infrared regime. The results of the simulations indicate that the overall efficiencies of the seeded and SASE FELs are comparable for a uniform wiggler but that the output spectrum for the SASE FEL is much broader than for the seeded case. For a tapered wiggler, the efficiency enhancement in the SASE FEL is less than that found in the seeded example due to the broader excited spectrum that detunes the tapered wiggler interaction.

  6. Enhanced spontaneous emission of electric dipole by nano-optical antenna

    Microsoft Academic Search

    H. Gao; K. Li; F. M. Kong; H. Xie; J. Zhao

    2009-01-01

    We study the characteristics of nano-optical antenna made of two gold nano-particles by three dimensional numerical calculations at visible and near infrared band. To carry the computational burden and guarantee the precision and speed of a 3D FDTD calculation, adaptive mesh refinement technology is used. We first highlight the concrete way of controlling over the emitter position to fulfill the

  7. Even-odd effects in prompt emission of spontaneously fissioning even-even Pu isotopes

    NASA Astrophysics Data System (ADS)

    Tudora, A.; Hambsch, F.-J.; Giubega, G.; Visan, I.

    2015-01-01

    The available experimental Y (A , TKE) data for 236,238,240,242,244Pu(SF) together with the Zp model prescription with appropriate parameters allows the investigation of even-odd effects in fragment distributions. The size of the global even-odd effect in Y (Z) is decreasing from 244Pu(SF) to 236Pu(SF) confirming the general observation of a decrease of the even-odd effect with the fissility parameter. Charge polarizations (?Z) and root-mean squares (rms) as a function of A of 236-244Pu(SF) were obtained for the first time. In the asymmetric fission region both ?Z (A) and rms (A) exhibit oscillations with a periodicity of about 5 mass units due to the even-odd effects. The total average charge deviations < ?Z > (obtained by averaging ?Z (A) over the experimental Y (A) distribution) are of about |0.5| for all studied Pu(SF) systems. The comparison of the calculated ?Z (A) and rms (A) of 240Pu(SF) with those of 239Pu (nth , f) reported by Wahl shows an in-phase oscillation with a higher amplitude in the case of 240Pu(SF), confirming the higher even-odd effect in the case of SF. As in the previously studied cases (233,235U (nth , f), 239Pu (nth , f), 252Cf(SF)) the even-odd effects in the prompt emission of 236-244Pu(SF) are mainly due to the Z even-odd effects in fragment distributions and charge polarizations and the N even-odd effects in the average neutron separation energies from fragments < Sn >. The size of the global N even-odd effect in < Sn > is decreasing with the fissility parameter, being higher for the Pu(SF) systems compared to the previously studied systems. The prompt neutron multiplicities as a function of Z, ? (Z), exhibit sawtooth shapes with a visible staggering for asymmetric fragmentations. The size of the global Z even-odd effect in ? (Z) exhibits a decreasing trend with increasing fissility. The average prompt neutron multiplicities as a function of TKE show an increase of the even-odd effect with increasing TKE, with global effect sizes close to each other (a decrease of the effect for heavier fissioning nuclei is not observed here). The amounts of the global even-odd effect in Y (Z) and of the N even-odd effect in < Sn > of 240Pu(SF) are larger compared to 239Pu (nth , f). This fact affects the prompt emission leading to a lower Z even-odd effect in the prompt neutron multiplicity of 240Pu(SF) compared to 239Pu (nth , f).

  8. 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...

  9. Unregulated emissions from a heavy-duty diesel engine with various fuels and emission control systems.

    PubMed

    Tang, Shida; Frank, Brian P; Lanni, Thomas; Rideout, Greg; Meyer, Norman; Beregszaszy, Chris

    2007-07-15

    This study evaluated the effects of various combinations of fuels and emission control technologies on exhaust emissions from a heavy-duty diesel engine tested on an engine dynamometer. Ten fuels were studied in twenty four combinations of fuel and emission control technology configurations. Emission control systems evaluated were diesel oxidation catalyst (DOC), continuously regenerating diesel particulate filter (CRDPF), and the CRDPF coupled with an exhaust gas recirculation system (EGRT). The effects of fuel type and emission control technology on emissions of benzene, toluene, ethylbenzene, xylene (BTEX), and 1,3-butadiene, elemental carbon and organic carbon (EC/OC), carbonyls, polycyclic aromatic hydrocarbons (PAHs), and nitro-PAHs (n-PAHs) are presented in this paper. Regulated gaseous criteria pollutants of total hydrocarbons (THC), carbon monoxide (CO), oxides of nitrogen (NO(x)) and particulate matter (PM) emissions have been reported elsewhere. In general, individual unregulated emission with a CRDPF or an EGRT system is similar (at very low emission level) or much lower than that operating solely with a DOC and choosing a "best" fuel. The water emulsion PuriNO(x) fuel exhibited higher BTEX, carbonyls and PAHs emissions compared to other ultralow sulfur diesel (ULSD) fuels tested in this study while n-PAH emissions were comparable to that from other ULSD fuels. Naphthalene accounted for greater than 50% of the total PAH emissions in this study and there was no significant increase of n-PAHs with the usage of CRDPF. PMID:17711220

  10. Fission fragment K x-ray emission and nuclear charge distribution for thermal neutron fission of 233U, 235U, 239Pu and spontaneous fission of 252Cf

    Microsoft Academic Search

    W. Reisdorf; J. P. Unik; H. C. Griffin; L. E. Glendenin

    1971-01-01

    The emission of K X-rays by fission fragments within ~ 1 nsec after fission has been studied as a function of fragment mass and nuclear charge for thermal neutron-induced fission of 233U, 235U, 239Pu and spontaneous fission of 252Cf. This work is based on a simultaneous measurement of the fragment kinetic energies to obtain the fragment masses and high-resolution measurement

  11. Three-dimensional simulations of the generation of one Angstrom radiation by a self-amplified spontaneous emission free-electron laser

    SciTech Connect

    Goldstein, J.C.; Elliott, C.J.; Schmitt, M.J.

    1990-01-01

    Three-dimensional numerical simulations of the generation of one Angstrom x-rays by a free-electron laser operating in the self-amplified spontaneous emission mode have been performed. Using model electron beam and wiggler parameters, we have investigated the length of wiggler needed to just avoid bandwidth broadening effects associated with gain saturation, and we have also obtained requirements for wiggler field errors to avoid significant loss of performance. 14 refs., 5 figs., 1 tab.

  12. Spontaneous emission from radiative chiral nematic liquid crystals at the photonic band-gap edge: An investigation into the role of the density of photon states near resonance

    NASA Astrophysics Data System (ADS)

    Mavrogordatos, Th. K.; Morris, S. M.; Wood, S. M.; Coles, H. J.; Wilkinson, T. D.

    2013-06-01

    In this article, we investigate the spontaneous emission properties of radiating molecules embedded in a chiral nematic liquid crystal, under the assumption that the electronic transition frequency is close to the photonic edge mode of the structure, i.e., at resonance. We take into account the transition broadening and the decay of electromagnetic field modes supported by the so-called “mirrorless”cavity. We employ the Jaynes-Cummings Hamiltonian to describe the electron interaction with the electromagnetic field, focusing on the mode with the diffracting polarization in the chiral nematic layer. As known in these structures, the density of photon states, calculated via the Wigner method, has distinct peaks on either side of the photonic band gap, which manifests itself as a considerable modification of the emission spectrum. We demonstrate that, near resonance, there are notable differences between the behavior of the density of states and the spontaneous emission profile of these structures. In addition, we examine in some detail the case of the logarithmic peak exhibited in the density of states in two-dimensional photonic structures and obtain analytic relations for the Lamb shift and the broadening of the atomic transition in the emission spectrum. The dynamical behavior of the atom-field system is described by a system of two first-order differential equations, solved using the Green's-function method and the Fourier transform. The emission spectra are then calculated and compared with experimental data.

  13. Valence subband coupling effect on polarization of spontaneous emissions from Al-rich AlGaN/AlN quantum wells.

    PubMed

    Lu, Huimin; Yu, Tongjun; Yuan, Gangcheng; Jia, Chuanyu; Chen, Genxiang; Zhang, Guoyi

    2012-12-01

    The optical polarization properties of Al-rich AlGaN/AlN quantum wells (QWs) were investigated using the theoretical model based on the k·p method. Numerical results show that there is valence subband coupling which can influence the peak emission wavelength and emission intensity for TE and TM polarization components from Al-rich AlGaN/AlN QWs. Especially the valence subband coupling could be strong enough when CH1 is close to HH1 and LH1 subbands to modulate the critical Al content switching dominant emissions from TE to TM polarization. It is believed that the valence subband coupling may give important influence on polarization properties of spontaneous emissions and should be considered in designing high efficiency AlGaN-based ultraviolet (UV) LEDs. PMID:23262689

  14. Elevation of cell cycle control proteins during spontaneous immortalization of human keratinocytes.

    PubMed Central

    Rice, R H; Steinmann, K E; deGraffenried, L A; Qin, Q; Taylor, N; Schlegel, R

    1993-01-01

    A human line of spontaneously immortalized keratinocytes (SIK cells) has been derived from ostensibly normal epidermis and has proven useful in dissecting molecular changes associated with immortalization. The original cultures had a normal karyotype and a colony forming efficiency of approximately 3% through 10 passages. At passage 15, after which normal strains ordinarily senesce, these cells continued vigorous growth and gradually increased in colony forming efficiency, stabilizing at approximately 30% by passage 40. During the early stage of increasing colony forming efficiency, the cells acquired a single i(6p) chromosomal aberration and 5- to 10-fold increases in expression of the cell-cycle control proteins cyclin A, cyclin B, and p34cdc2. Additional chromosomal aberrations accumulated at later passages (i(8q) and +7), but the i(6p) and the increased expression of cell-cycle proteins were maintained, raising the possibility that these features were important for immortalization. Regulation of cell growth and differentiation in the cultures appeared minimally altered compared with normal keratinocytes as judged by their microscopic appearance and generation of abortive colonies, sensitivity to growth suppression by transforming growth factor-beta and tetradecanoylphorbol acetate, and dependence upon epidermal growth factor for progressive growth. Images PMID:8443416

  15. 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

  16. 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.

  17. 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

  18. Achieving 'perfect' molecular discrimination via coherent control and stimulated emission

    NASA Astrophysics Data System (ADS)

    Clow, Stephen D.; Hölscher, Uvo C.; Weinacht, Thomas C.

    2009-11-01

    We illustrate how stimulated emission near threshold can turn modest coherent control yields into essentially perfect discrimination between systems. We demonstrate selective two-photon driven superfluorescence in atomic Rb and Na, where the shape of an ultrafast drive laser controls which atoms superfluoresce. Furthermore, we demonstrate high contrast selectivity in driving stimulated emission from dye molecules in solution by tailoring the shape of the ultrafast drive laser pulse. In both cases, we demonstrate discrimination with a control factor of about 104.

  19. A double-blind, placebo-controlled study of the effects of lidocaine patch therapy on brain activity for spontaneous pain

    E-print Network

    Apkarian, A. Vania

    has been shown to modulate brain activity associated with the spontaneous pain of post-controlled study of brain activity for spontaneous pain and its modulation by Lidocaine patch therapy. · Here we for CBP Thro bbin g Shooting Sta bbin gSharp C ra m pin g G naw in g H ot-burn in gAchin gH eavy

  20. Effects of alverine on the spontaneous electrical activity and nervous control of the proximal colon of the rabbit.

    PubMed

    Bouvier, M; Grimaud, J C; Abysique, A; Chiarelli, P

    1992-01-01

    To analyse the mechanisms of the antispasmodic action of alverine, the effects of this drug on the spontaneous motility and nervous control of the proximal colon of the rabbit were studied in vivo. The electrical activity of the colonic smooth muscle was recorded using extracellular electrodes. The parasympathetic efferents were activated by electrical stimulation of distal ends of the vagus nerves. Alverine given intravenously inhibits spike potentials without modifying the slow waves. Excitatory and inhibitory responses induced by parasympathetic efferent stimulations, as well as the hyperpolarization due to intraluminal distension, were also blocked after drug injection. Our results show that alverine is able to block the spontaneous contractions and the nervous control of rabbit proximal colon, indicating that this drug has powerful antispasmodic effects. PMID:1397853

  1. 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 ...

  2. EMISSIONS AND TRAFFIC CONTROL: AN EMPIRICAL APPROACH

    Microsoft Academic Search

    H. Christopher Frey; Nagui Rouphail; Alper Unal; James Colyar

    2000-01-01

    The purpose of this study is to evaluate the effect of traffic signal coordination and timing on real-world, on-road emissions. A portable instrument, the OEM-2100 manufactured by Clean Air Technologies International, Inc., was used to measure on-road tailpipe emissions of carbon monoxide (CO), nitric oxide (NO), hydrocarbons (HC), and carbon dioxide (CO2) on a second- by-second basis during actual driving.

  3. Spontaneous pushing to prevent postpartum urinary incontinence: a randomized, controlled trial

    PubMed Central

    Miller, Janis M.; Guo, Ying; Ashton-Miller, James A.; DeLancey, John O. L.; Sampselle, Carolyn M.

    2014-01-01

    Introduction and hypothesis The risk for urinary incontinence can be 2.6-fold greater in women after pregnancy and childbirth compared with their never-pregnant counterparts, with the incidence increasing with parity. We tested the hypothesis that the incidence of de novo postpartum urinary incontinence in primiparous women is reduced with the use of spontaneous pushing alone or in combination with perineal massage compared with women who experienced traditional directed pushing for second-stage management. Methods This was a prospective clinical trial enrolling and randomizing 249 women into a four-group design: (1) routine care with coached or directed pushing, (2) spontaneous self-directed pushing, (3) prenatal perineal massage initiated in the third trimester, and (4) the combination of spontaneous pushing plus perineal massage. Self-report of incontinence was assessed using analysis of variance (ANOVA) and covariance (ANCOVA) models in 145 remaining women at 12 months postpartum using the Leakage Index, which is sensitive to minor leakage. Results No statistical difference in the incidence of de novo postpartum incontinence was found based on method of pushing (spontaneous/directed) (P value=0.57) or in combination with prenatal perineal massage (P value=0.57). Fidelity to pushing treatment of type was assessed and between-groups crossover detected. Conclusions Spontaneous pushing did not reduce the incidence of postpartum incontinence experienced by women 1 year after their first birth due to high cross-over between randomization groups. PMID:22829349

  4. Self-amplified spontaneous emission saturation at the Advanced Photon Source free-electron laser (abstract) (invited)

    NASA Astrophysics Data System (ADS)

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

    2002-03-01

    Today, many bright photon beams in the ultraviolet and x-ray wavelength range are produced by insertion devices installed in specially designed third-generation storage rings. There is the possibility of producing photon beams that are orders of magnitude brighter than presently achieved at synchrotron sources, by using self-amplified spontaneous emission (SASE). At the Advanced Photon Source (APS), the low-energy undulator test line (LEUTL) free-electron laser (FEL) project was built to explore the SASE process in the visible through vacuum ultraviolet wavelength range. While the understanding gained in these experiments will guide future work to extend SASE FELs to shorter wavelengths, the APS FEL itself will become a continuously tunable, bright light source. Measurements of the SASE process to saturation have been made at 530 and 385 nm. A number of quantities were measured to confirm our understanding of the SASE process and to verify that saturation was reached. The intensity of the FEL light was measured versus distance along the FEL, and was found to flatten out at saturation. The statistical variation of the light intensity was found to be wide in the exponential gain region where the intensity is expected to be noisy, and narrower once saturation was reached. Absolute power measurements compare well with GINGER simulations. The FEL light spectrum at different distances along the undulator line was measured with a high-resolution spectrometer, and the many sharp spectral spikes at the beginning of the SASE process coalesce into a single peak at saturation. The energy spread in the electron beam widens markedly after saturation due to the number of electrons that transfer a significant amount of energy to the photon beam. Coherent transition radiation measurements of the electron beam as it strikes a foil provide additional confirmation of the microbunching of the electron beam. The quantities measured confirm that saturation was indeed reached. Details are given in Milton et al., Science 292, 2037 (2001) (also online at www.sciencexpress.org as 10.1126/science. 1059955, 17 May 2001), and Lewellen et al., "Present Status and Recent Results from the APS SASE FEL," to be published in the Proceedings of the 23rd International Free-Electron Laser Conference, Darmstadt, Germany, 20-24 August 2001.

  5. 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

  6. Integrated emissions control system for residential CWS furnace

    SciTech Connect

    Balsavich, J.C. Jr.

    1991-11-01

    To meet the emission goals set by the Pittsburgh Energy Technology Center (PETC), Tecogen Inc. is developing a novel, integrated emission 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. In addition to controlling SO{sub 2} emissions, the reactor provides a means of extracting a substantial amount of the particulates present in the combustion gases. Final cleanup of any fine particulates exiting the reactor, including respirable-sized particulates, is completed with the use of high efficiency bag filters. With SO{sub 2} and particulate emissions being dealt with by an emissions control reactor and bag filters, the control of NO{sub x} emissions needs to be addressed. Under a previous contract with PETC (contract No. AC22-87PC79650), Tecogen developed a residential-scale Coal Water Slurry (CWS) combustor. 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} emissions.

  7. Environmental controls over methyl halide emissions from rice paddies

    Microsoft Academic Search

    K. R. Redeker; R. J. Cicerone

    2004-01-01

    This paper examines primary controlling factors that affect methyl halide emissions from rice paddy ecosystems. Observations of four cultivars under multiple growth conditions during studies in commercial fields and the University of California, Irvine, greenhouse lead to the conclusion that daily emissions of methyl halides are primarily determined by the growth stage of the rice plant, with the exception that

  8. 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

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

    Microsoft Academic Search

    Anna G. Stefanopoulou; Ilya Kolmanovsky; James S. Freudenberg

    2000-01-01

    The emission control problem for an automotive direct injected compression ignition (diesel) engine equipped with exhaust gas recirculation (EGR) and a variable geometry turbocharger (VGT) is considered. The objective is to operate the engine to meet driver's torque demand and minimize NOx emissions while at the same time avoiding visible smoke generation. It is demonstrated that the steady-state optimization of

  10. IRON AND STEEL PLANT OPEN SOURCE FUGITIVE EMISSION CONTROL EVALUATION

    EPA Science Inventory

    The report gives results of measurements of the control efficiency of various techniques used to mitigate emissions from open dust sources in the iron and steel industry. Of estimated emissions of 88,800 tons/year suspended particulate in 1978 (based on a 10-plant survey), 70, 13...

  11. 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...

  12. 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 emissions and leading to a reduction in global warming. Citation: Ming, Y., L. M. Russell, and D. FHEALTH AND CLIMATE POLICY IMPACTS ON SULFUR EMISSION CONTROL Received 30 December 2004; revised 14

  13. 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 ...

  14. PERFORMANCE OF EMISSIONS CONTROL SYSTEMS ON MUNICIPAL WASTE COMBUSTORS

    EPA Science Inventory

    The paper reports results of several EPA-supported field evaluations of data on gaseous pollutant emissions from modern municipal waste combustors/incinerators and emissions control by flue gas cleaning systems. The results are presented in terms of acid gas (HCl and SO2), trace ...

  15. X-RAY NONLINEAR OPTICAL PROCESSES IN ATOMS USING A SELF-AMPLIFIED SPONTANEOUS EMISSION FREE-ELECTRON LASER

    SciTech Connect

    Rohringer, N

    2008-08-08

    X-ray free electron lasers (xFEL) will open new avenues to the virtually unexplored territory of non-linear interactions of x rays with matter. Initially xFELs will be based on the principle of self-amplified spontaneous emission (SASE). Each SASE pulse consists of a number of coherent intensity spikes of random amplitude, i.e. the process is chaotic and pulses are irreproducible. The coherence time of SASE xFELs will be a few femtoseconds for a photon energy near 1 keV. The importance of coherence properties of light in non-linear optical processes was theoretically discovered in the early 1960s. In this contribution we will illustrate the impact of field chaoticity on x-ray non-linear optical processes on neon for photon energies around 1 keV and intensities up to 10{sup 18} W/cm{sup 2}. Resonant and non-resonant processes are discussed. The first process to be addressed is the formation of a double-core hole in neon by photoionization with x rays above 1.25 keV energy. In contrast to the long-wavelength regime, non-linear optical processes in the x-ray regime are characterized in general by sequential single-photon single-electron interactions. Despite this fact, the sequential absorption of multiple x-ray photons depends on the statistical properties of the radiation field. Treating the x rays generated by a SASE FEL as fully chaotic, a quantum-mechanical analysis of inner-shell two-photon absorption is performed. By solving a system of time-dependent rate equations, we demonstrate that double-core hole formation in neon via x-ray two-photon absorption is enhanced by chaotic photon statistics. At an intensity of 10{sup 16} W/cm{sup 2}, the statistical enhancement is about 30%, much smaller than typical values in the optical regime. The second part of this presentation discusses the resonant Auger effect of atomic neon at the 1s-3p transition (at 867.1 eV). For low X-ray intensity, the excitation process 1s {yields} 3p in Neon can be treated perturbatively. The core-hole excited 1s{sup -1} 3p state is embedded in the continuum and decays via Auger-process on the timescale of approximately 5 fs. Increasing the x-ray intensity above 1.5 x 10{sup 18} W/cm{sup 2}, a peak intensity accessible with xFEL sources in the near future, x-ray induced emission from 3p back to 1s becomes possible, i.e. Rabi oscillations between these two levels can be induced. For the numerical analysis of this process, an effective two-level model, including a description of the resonant Auger decay process, is employed. The observation of x-ray-driven atomic populations dynamics in the time domain is challenging for chaotic xFEL pulses. In addition to requiring single-shot measurements, sub-femtosecond temporal resolution would be needed. The Rabi oscillations will, however, be imprinted on the kinetic energy distribution of the resonant Auger electron (see Fig. 1). Measuring the resonant Auger-electron line profile will provide information on both atomic population dynamics and x-ray pulse properties.

  16. 40 CFR 52.1384 - Emission control regulations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...OF IMPLEMENTATION PLANS (CONTINUED) Montana § 52.1384 Emission control regulations. (a) Administrative Rules of Montana 17.8.309(5)(b) and...exhibit A of the stipulation between the Montana Department of Environmental...

  17. 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 ...

  18. A Nested Case-Control Study of First-Trimester Maternal Vitamin D Status and Risk for Spontaneous Preterm Birth

    PubMed Central

    Baker, Arthur M.; Haeri, Sina; Camargo, Carlos A.; Stuebe, Alison M.; Boggess, Kim A.

    2015-01-01

    We assessed if first-trimester vitamin D deficiency is more prevalent in women who experienced a spontaneous preterm birth compared with women who delivered at term. We conducted a nested case-control study of pregnant women who had previously given blood for first-trimester combined screening for trisomy 21 and subsequently delivered at a tertiary hospital between November 2004 and July 2009. From an overall cohort of 4225 women, 40 cases of spontaneous preterm birth (?23 0/7 and ?34 6/7 weeks) were matched by race/ethnicity with 120 women delivering at term (?37 0/7 weeks) with uncomplicated pregnancies. Banked maternal serum was used to measure maternal 25-hydroxyvitamin D [25(OH)D]. The prevalence of first-trimester maternal vitamin D deficiency [25(OH)D <50 nmol/L] was comparable among women who subsequently delivered preterm compared with controls (7.5% versus 6.7%, p=0.90). The median 25(OH)D level for all subjects was 89 nmol/L (interquartile range, 73 to 106 nmol/L). Seventy-three percent (117/160) of the cohort had sufficient vitamin D levels [25(OH)D ?75 nmol/L]. In a cohort of pregnant women with mostly sufficient levels of first-trimester serum 25(OH)D, vitamin D deficiency was not associated with spontaneous preterm birth. PMID:21500145

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 40 CFR 63.325 - Determination of equivalent emission control technology.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...equivalent emission control technology. 63.325 Section 63...Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED...equivalent emission control technology. (a) Any person...illustrating the emission control technology, its operation and...

  4. Sulfur oxide adsorbents and emissions control

    DOEpatents

    Li, Liyu (Richland, WA); King, David L. (Richland, WA)

    2006-12-26

    High capacity sulfur oxide absorbents utilizing manganese-based octahedral molecular sieve (Mn--OMS) materials are disclosed. An emissions reduction system for a combustion exhaust includes a scrubber 24 containing these high capacity sulfur oxide absorbents located upstream from a NOX filter 26 or particulate trap.

  5. 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.

  6. Angular distribution of polarized spontaneous emissions and its effect on light extraction behavior in InGaN-based light emitting diodes

    SciTech Connect

    Yuan, Gangcheng; Chen, Xinjuan; Yu, Tongjun, E-mail: tongjun@pku.edu.cn; Lu, Huimin; Chen, Zhizhong; Kang, Xiangning; Wu, Jiejun; Zhang, Guoyi [State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China)

    2014-03-07

    Angular intensity distributions of differently polarized light sources in multiple quantum wells (MQWs) and their effects on extraction behavior of spontaneous emission from light emitting diode (LED) chips have been studied. Theoretical calculation based on k·p approximation, ray tracing simulation and angular electroluminescence measurement were applied in this work. It is found that the electron-hole recombination in the InGaN MQWs produces a spherical distribution of an s-polarized source and a dumbbell-shaped p-polarized source. Light rays from different polarized sources experience different extraction processes, determining the polarization degree of electro-luminescence and extraction efficiency of LEDs.

  7. Effect of the coherence properties of self-amplified-spontaneous-emission x-ray free electron lasers on single-particle diffractive imaging.

    PubMed

    Hau-Riege, Stefan P

    2008-02-18

    The longitudinal coherence properties of self-amplified-spontaneous- emission x-ray free electron lasers limit the resolution of single-particle diffraction imaging. We found that for the Linac Coherent Light Source (LCLS) at a wavelength of 1.5 A the particles have to be smaller than 500 nm in diameter to achieve atomic-resolution imaging with a resolution length of less than 2 A, suggesting that the longitudinal coherence is sufficient for imaging most biomolecular samples of interest. PMID:18542368

  8. SUPPORTING INFORMATION Control of initiation, rate, and routing of spontaneous capillary-driven flow of liquid

    E-print Network

    Ismagilov, Rustem F.

    spontaneously on fast-flow chip (Regime I). Droplets of 0.1M Fe(SCN)3 flowed through 55 mPas silicone oil of 0.1M Fe(SCN)3 flowed through 55 mPas silicone oil on a dichlorodimethylsilanzied glass chip

  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. Programmable smart electron emission controller for hot filament.

    PubMed

    Flaxer, Eli

    2011-02-01

    In electron ionization source, electrons are produced through thermionic emission by heating a wire filament, accelerating the electrons by high voltage, and ionizing the analyzed molecules. In such a system, one important parameter is the filament emission current that determines the ionization rate; therefore, one needs to regulate this current. On the one hand, fast responses control is needed to keep the emission current constant, but on the other hand, we need to protect the filament from damage that occurs by large filaments current transients and overheating. To control our filament current and emission current, we developed a digital circuit based on a digital signal processing controller that has several modes of operation. We used a smart algorithm that has a fast response to a small signal and a slow response to a large signal. In addition, we have several protective measures that prevent the current from reaching unsafe values. PMID:21361637

  11. Spectroscopic studies, fluorescence quenching by molecular oxygen and amplified spontaneous emission of 1,4-bis [2-(2-pyridyl) vinyl] benzene (P2VB) diolefinic laser dye

    NASA Astrophysics Data System (ADS)

    El-Daly, Samy A.; Ebeid, E. M.

    2014-04-01

    The UV-visible electronic absorption spectra, molar absorptivity, fluorescence spectra, fluorescence quantum yield and excited state lifetime of 1,4-bis [2-(2-pyridyl) vinyl] benzene P2VB were measured in different solvents. The fluorescence quenching of P2VB by molecular oxygen was also studied using lifetime measurements. A 2 × 10-4 mol dm-3 solution of P2VB in dimethyl formamide (DMF) gave amplified spontaneous emission (ASE) in blue spectral region with emission maximum at 420 nm upon pumping by 337.1 nitrogen laser pulse. The photochemical quantum yields (?c) of trans-cis photoisomerization of P2VB were calculated in different organic solvents. The photoreactivity of P2VB are also studied PMMA matrix.

  12. Spontaneous ultra-weak light emissions from wheat seedlings are rhythmic and synchronized with the time profile of the local gravimetric tide.

    PubMed

    Moraes, Thiago A; Barlow, Peter W; Klingelé, Emile; Gallep, Cristiano M

    2012-06-01

    Semi-circadian rhythms of spontaneous photon emission from wheat seedlings germinated and grown in a constant environment (darkened chamber) were found to be synchronized with the rhythm of the local gravimetric (lunisolar) tidal acceleration. Time courses of the photon-count curves were also found to match the growth velocity profile of the seedlings. Pair-wise analyses of the data--growth, photon count, and tidal--by local tracking correlation always revealed significant coefficients (P?>?0.7) for more than 80% of any of the time periods considered. Using fast Fourier transform, the photon-count data revealed periodic components similar to those of the gravimetric tide. Time courses of biophoton emissions would appear to be an additional, useful, and innovative tool in both chronobiological and biophysical studies. PMID:22639076

  13. Spontaneous ultra-weak light emissions from wheat seedlings are rhythmic and synchronized with the time profile of the local gravimetric tide

    NASA Astrophysics Data System (ADS)

    Moraes, Thiago A.; Barlow, Peter W.; Klingelé, Emile; Gallep, Cristiano M.

    2012-06-01

    Semi-circadian rhythms of spontaneous photon emission from wheat seedlings germinated and grown in a constant environment (darkened chamber) were found to be synchronized with the rhythm of the local gravimetric (lunisolar) tidal acceleration. Time courses of the photon-count curves were also found to match the growth velocity profile of the seedlings. Pair-wise analyses of the data—growth, photon count, and tidal—by local tracking correlation always revealed significant coefficients ( P > 0.7) for more than 80% of any of the time periods considered. Using fast Fourier transform, the photon-count data revealed periodic components similar to those of the gravimetric tide. Time courses of biophoton emissions would appear to be an additional, useful, and innovative tool in both chronobiological and biophysical studies.

  14. Emission control technology for stationary natural gas engines

    Microsoft Academic Search

    C. M. Urban; H. E. Dietzmann; El R. Fancik

    1989-01-01

    This paper summarizes the status of NOx emission control technology for stationary reciprocating natural gas engines. It provides information on most of the known methods of NOx control for natural gas engines that are in use, are being considered for use, of may be considered for use.

  15. Biofiltration: An Innovative Air Pollution Control Technology For VOC Emissions

    Microsoft Academic Search

    Gero Leson; Arthur M. Winer

    1991-01-01

    Biofiltration is a relatively recent air pollution control (APC) technology in which off-gases containing biodegradable volatile organic compounds (VOC) or inorganic air toxics are vented through a biologically active material. This technology has been successfully applied in Germany and The Netherlands in many full-scale applications to control odors, VOC and air toxic emissions from a wide range of industrial and

  16. Humidity control of particle emissions in aeolian systems

    Microsoft Academic Search

    Cheryl McKenna Neuman; Steven Sanderson

    2008-01-01

    Humidity is an important control of the wind speed required to entrain particles into an air flow and is well known to vary on a global scale, as do dust emissions. This paper reports on wind tunnel experiments which quantify this control through placing a polymer capacitance sensor immediately at the bed surface. The sensor measured changes in the humidity

  17. Mercury emissions control technologies for mixed waste thermal treatment

    Microsoft Academic Search

    A. Chambers; M. Knecht; N. Soelberg; D. Eaton; D. Roberts; T. Broderick

    1997-01-01

    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

  18. Control of nitrogen oxide emissions from power plant boilers

    Microsoft Academic Search

    Bartok

    1973-01-01

    The control of nitrogen oxide emissions from power plant boilers is discussed. Pollutant NOx is essentially all in the form of nitric oxide and nitrogen dioxide. In the atmosphere of urban centers the concentration of NOx can be 50 to 100 times that of the natural background, which is only about 1 to 5 ppb. Frequently, control strategies are contradictory

  19. 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...

  20. CONTROL OF SULFUR EMISSIONS FROM OIL SHALE RETORTS

    EPA Science Inventory

    The objectives of this study were to determine the best available control technology (BACT) for control of sulfur emissions from oil shale processing facilities and then to develop a design for a mobile slipstream pilot plant that could be used to test and demonstrate that techno...

  1. Influence of the CdSe quantum dots concentration on the amplified spontaneous emission from the conjugated polymer (MEH-PPV) in solution

    NASA Astrophysics Data System (ADS)

    Ibnaouf, K. H.

    2015-04-01

    The spectral properties of a conjugated polymer poly [2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene] (MEH-PPV) in benzene have been studied intensively. The fluorescence spectra for MEH-PPV, under low concentrations, have shown two peaks around 560 nm and 600 nm, which could be attributed to the monomer and excimer states respectively. In our earlier communication, we had shown that MEH-PPV alone could produce amplified spontaneous emission (ASE) only in its excimeric state (600 nm). The spectral properties of 5 nm size of CdSe (core) quantum dots have been investigated. The fluorescence spectra of CdSe core in benzene showed only one band at 590 nm. Mixtures made of MEH-PPV and CdSe (core) quantum dots have been utilized for studying the amplified spontaneous emission characteristics (ASE) in an organic solution under laser excitation. When the mixture was pumped by the third harmonic of Nd:YAG (355 nm), we observed two ASE peaks; one at 575 nm and another at 595 nm. These ASE peaks could arise from the monomer and excimer states of MEH-PPV. This is perhaps the first report on the influence of quantum dots on the laser from the conjugated polymer MEH-PPV, in liquid solution.

  2. Optical control of the emission direction of a quantum dot

    SciTech Connect

    Luxmoore, I. J., E-mail: i.j.luxmoore@exeter.ac.uk [College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF (United Kingdom); Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH (United Kingdom); Wasley, N. A.; Fox, A. M.; Skolnick, M. S. [Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH (United Kingdom)] [Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH (United Kingdom); Ramsay, A. J. [Hitachi Cambridge Laboratory, Hitachi Europe Ltd, Cambridge CB3 OHE (United Kingdom)] [Hitachi Cambridge Laboratory, Hitachi Europe Ltd, Cambridge CB3 OHE (United Kingdom); Thijssen, A. C. T.; Oulton, R. [H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, Tyndall Avenue, Bristol BS8 1TL (United Kingdom)] [H. H. Wills Physics Laboratory and Department of Electrical and Electronic Engineering, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Hugues, M. [Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom) [Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); CNRS-CRHEA, rue Bernard Grégory, 06560 Valbonne (France)

    2013-12-09

    Using the helicity of a non-resonant excitation laser, control over the emission direction of an InAs/GaAs quantum dot is demonstrated. The quantum dot is located off-center in a crossed-waveguide structure, such that photons of opposite circular polarization are emitted into opposite waveguide directions. By preferentially exciting spin-polarized excitons, the direction of emission can therefore be controlled. The directional control is quantified by using the ratio of the intensity of the light coupled into the two waveguides, which reaches a maximum of ±35%.

  3. 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

  4. Coal-fueled diesel emissions control technology development

    SciTech Connect

    Cook, C.; Gal, E.; Mengel, M.; Van Kleunen, W.

    1993-03-01

    The objective of this project is to develop an emissions control system for a GE locomotive powered by a Coal Water Slurry (CWS) fuel diesel engine. The development effort is directed toward reducing particulate matter, SO{sub 2} and NO{sub x} emissions from the engine exhaust gas at 700--800F and 1-2 psig. The commercial system should be economically attractive while subject to limited space constraints. After testing various alternatives, a system composed of a barrier filter with sorbent injection ups was selected for controlling particulates, SO{sub 2} and NO{sub x} emissions. In bench scale and 500 acfm slip s tests, removal efficiencies greater than 90% for SO{sub 2} and 85% for NO{sub x} were achieved. Particulate emissions from the barrier filter are within NSPS limits.

  5. Coal-fueled diesel emissions control technology development

    SciTech Connect

    Cook, C.; Gal, E.; Mengel, M.; Van Kleunen, W.

    1993-01-01

    The objective of this project is to develop an emissions control system for a GE locomotive powered by a Coal Water Slurry (CWS) fuel diesel engine. The development effort is directed toward reducing particulate matter, SO[sub 2] and NO[sub x] emissions from the engine exhaust gas at 700--800F and 1-2 psig. The commercial system should be economically attractive while subject to limited space constraints. After testing various alternatives, a system composed of a barrier filter with sorbent injection ups was selected for controlling particulates, SO[sub 2] and NO[sub x] emissions. In bench scale and 500 acfm slip s tests, removal efficiencies greater than 90% for SO[sub 2] and 85% for NO[sub x] were achieved. Particulate emissions from the barrier filter are within NSPS limits.

  6. Systems and methods for controlling diesel engine emissions

    DOEpatents

    Webb, Cynthia Chaffin; Weber, Phillip Anthony; Khair, Magdi K.

    2004-06-01

    Systems and methods for controlling diesel engine emissions, including, for example, oxides of nitrogen emissions, particulate matter emissions, and the like. The emission control system according to this invention is provided in the exhaust passageway of a diesel engine and includes a catalyst-based particulate filter; and first and second lean NO.sub.x trap systems coupled to the catalyst-based particulate filter. The first and second lean NO.sub.x trap systems are arranged in a parallel flow configuration with each other. Each of the first and second lean NO.sub.x trap systems include a carbon monoxide generating catalyst device, a sulfur trap device, a lean NO.sub.x device, a supplemental fuel injector device, and a plurality of flow diverter devices.

  7. 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.

  8. Positional control of plasmonic fields and electron emission

    SciTech Connect

    Word, R. C.; Fitzgerald, J. P. S.; Könenkamp, R., E-mail: rkoe@pdx.edu [Department of Physics, Portland State University, 1719 SW 10th Avenue, Portland, Oregon 97201 (United States)

    2014-09-15

    We report the positional control of plasmonic fields and electron emission in a continuous gap antenna structure of sub-micron size. We show experimentally that a nanoscale area of plasmon-enhanced electron emission can be motioned by changing the polarization of an exciting optical beam of 800?nm wavelength. Finite-difference calculations are presented to support the experiments and to show that the plasmon-enhanced electric field distribution of the antenna can be motioned precisely and predictively.

  9. 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

  10. 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

  11. Primary production control of methane emission from wetlands

    NASA Technical Reports Server (NTRS)

    Whiting, G. J.; Chanton, J. P.

    1993-01-01

    Based on simultaneous measurements of CO2 and CH4 exchange in wetlands extending from subarctic peatlands to subtropical marshes, a positive correlation between CH4 emission and net ecosystem production is reported. It is suggested that net ecosystem production is a master variable integrating many factors which control CH4 emission in vegetated wetlands. It is found that about 3 percent of the daily net ecosystem production is emitted back to the atmosphere as CH4. With projected stimulation of primary production and soil microbial activity in wetlands associated with elevated atmospheric CO2 concentration, the potential for increasing CH4 emission from inundated wetlands, further enhancing the greenhouse effect, is examined.

  12. 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.

  13. Spontaneous preterm delivery and gestational diabetes: the impact of glycemic control

    Microsoft Academic Search

    Yariv Yogev; Oded Langer

    2007-01-01

    Objective  Opinions differ whether the rate of spontaneous preterm delivery (sPTD) increases in pregnancies complicated with GDM. We\\u000a sought to characterize, which factors may influence the rate of sPTD in GDM.\\u000a \\u000a \\u000a \\u000a Methods  We conducted a retrospective study with 1,526 GDM patients, all treated at the same center by the same diabetic protocol using\\u000a self-blood glucose monitoring. The rate of sPTD was compared

  14. 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.

  15. 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.

  16. Coal-fueled diesel technology development emissions control

    NASA Astrophysics Data System (ADS)

    Vankleunen, W.; Kaldor, S.; Gal, E.; Mengel, M.; Arnold, M.

    1994-01-01

    General Electric Environmental Services, Inc. (GEESI), Emissions Control program activity ranged from control concept testing of 10 CFM slipstream from a coal-water-slurry (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 SO2 and NO(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.

  17. 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

  18. 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.

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

    NASA Astrophysics Data System (ADS)

    Jakubczyk, T.; Pacuski, W.; Smole?ski, T.; Golnik, A.; Florian, M.; Jahnke, F.; Kruse, C.; Hommel, D.; Kossacki, P.

    2012-09-01

    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.

  20. 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

  1. High guided mode-cavity mode coupling for an efficient extraction of spontaneous emission of a single quantum dot embedded in a photonic crystal nanobeam cavity

    NASA Astrophysics Data System (ADS)

    Enderlin, Alexandre; Ota, Yasutomo; Ohta, Ryuichi; Kumagai, Naoto; Ishida, Satomi; Iwamoto, Satoshi; Arakawa, Yasuhiko

    2012-08-01

    We demonstrate efficient extraction of a single InAs quantum dot spontaneous emission through an air-suspended waveguide to which a photonic crystal nanobeam cavity is coupled. First, the quantum dot emission into the cavity mode is enhanced due to a high Purcell effect arising from a large quality factor and a small mode volume of the cavity mode. Second, the cavity photons can be efficiently transferred to the guided mode by optimizing the design of a structure that exhibits a high coupling rate between the two modes. This configuration has lead to the observation of a high extraction efficiency (79%) of the quantum dot emission through the waveguide. Moreover, as a result of the high extraction efficiency to the guided mode, the unwanted microphotoluminescence coupling to the free space modes and detected from the top surface of the sample is strongly suppressed. Indeed, we show that it exhibits a negative peak as a function of the detuning between the cavity mode energy and the quantum dot transition energy.

  2. Factors and processes controlling methane emissions from rice fields

    Microsoft Academic Search

    H. U. Neue; R. Wassmann; H. K. Kludze; Wang Bujun; R. S. Lantin

    1997-01-01

    Understanding the major controlling factors of methane emissions from ricefields is critical for estimates of source strengths.\\u000a This paper reports results on the relationship of different plant characteristics and methane fluxes in ricefields.\\u000a \\u000a Methane fluxes in ricefields show distinct diel and seasonal variations. Diel variations are mainly controlled by soil solution\\u000a temperature and the partial pressure of methane. One or

  3. 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. ...

  4. Environmental factors controlling methane emissions for peatlands in Northern Minnesota

    Microsoft Academic Search

    Nancy B. Dise; Eville Gorham; Elon S. Verry

    1993-01-01

    Controls on methane emission from peatlands in northern Minnesota were investigated by correlation to environmental variables and by field manipulations. From September 1988 through September 1990, methane flux measurements were made at weekly to monthly intervals at six sites in the Marcell Experimental Forest, northern Minnesota (two open bog sites, two forested bog sites, a poor fen, and a fen

  5. ASSESSMENT OF THE USE OF FUGITIVE EMISSION CONTROL DEVICES

    EPA Science Inventory

    The report compares the efficiencies and utility consumptions expected from three fugitive emission control techniques--building evacuation, charged fog sprays, and water sprays with additives--if they were applied in primary lead and copper smelters. Estimates are provided of th...

  6. Internal combustion engine with exhaust emission control system

    Microsoft Academic Search

    M. Allione; F. Cavallino; P. Martinez; R. Schiavuzzi

    1981-01-01

    A four cylinder spark ignition internal combustion engine has an exhaust emission control system including means for admitting fresh air into the exhaust system in order to promote a further combustion of partly burnt components in the gases coming from the combustion chambers, this means include a ''reed'' valve connected to the exhaust ports leading from the first and fourth

  7. Analytical Framework to Evaluate Emission Control Systems for Marine Engines

    E-print Network

    Jayaram, Varalakshmi

    2010-01-01

    water in fuel emulsion (WFE) NO x control technology on the propulsionpropulsion-3/ (accessed 10/18/2010). Calder, N. Water Power.Water to Fuel on Emissions from a Large Marine Engine Chapter Summary Large two-stroke low-speed marine propulsion

  8. Fired heaters: nitrogen oxides emissions and controls. Final report

    Microsoft Academic Search

    S. A. Shareef; C. L. Anderson; L. E. Keller

    1988-01-01

    This report gives results of a study of nitrogen oxide (NOx) emissions from, and controls for, fired heaters. The petroleum-refining and chemical manufacturing industries account for most of fired-heater energy use with an estimated 4600 fired heaters in operation, in these two industries. The report gives a brief description of the design and operation of fired heaters. Descriptions of the

  9. Oscillation structures in the spontaneous emission rate of an atom in a medium with refractive index n between mirrors: a solvable model

    E-print Network

    H. J. Zhao; M. L. Du

    2006-12-18

    We study the multi-periodic oscillations in the spontaneous emission rate of an atom in a medium with refractive index n sandwiched between two parallel mirrors. The oscillations are not obvious in the analytical formula for the rate derived based on Fermi's golden rule but can be extracted using Fourier transforms by varying the system scale while holding the configuration. The oscillations are interpreted as interferences and correspond to various closed-orbits of the emitted photon going away from and returning to the atom. This system provides a rare example that the oscillations can be explicitly derived by following the emitted wave until it returns to the emitting atom. We demonstrate the summation over a large number of closed-orbits converges to the rate formula of golden rule.

  10. Combined planar imaging of schlieren photography with OH-LIPF and spontaneous OH-emission in a 2-D valveless pulse combustor

    SciTech Connect

    Ishino, Yojiro; Hasegawa, Tatsuya; Yamaguchi, Shigeki; Ohiwa, Norio

    1999-07-01

    Using a novel optical system, simultaneous imaging of schlieren photography and laser induced predissociation fluorescence of OH radicals (OH-LIPF) have been carried out to examine combustion processes and flame structure in a two-dimensional valveless pulse combustor. Simultaneous imaging of schlieren photographs and spontaneous OH-emission have also been made, in order to obtain information on the behavior of the flame front during a cycle of pulsation. The pulse combustor used in this experiment consists of a combustion chamber of a volume of 125 cm{sup 3} and a tailpipe of a length of 976 mm, which is followed by an automobile muffler. The fuel used is commercial grade gaseous propane.

  11. Ultra-deep stopband induced by spontaneous-emission-cancellation-like interference between two side-coupled zero-index-metamaterial-based resonators

    NASA Astrophysics Data System (ADS)

    Li, Y. H.; Dong, Z. D.; Sun, Y.; Tan, W.; Jiang, H. T.; Wang, Z. G.; Chen, H.

    2012-11-01

    In this paper, two side-coupled zero-index-metamaterial-based resonators that mimic the spontaneous-emission cancellation (SEC) effect are investigated numerically and experimentally. It is found that an interference-induced stopband as deep as -70 dB can be observed in a microstrip SEC structure whose size is even less than 0.5 cm2. More simulations about the electrical-field distributions demonstrate intuitively the underlying physics, i.e., the destructive interference between two side-coupled zero-index-metamaterial-based resonators. Our method of realizing ultra-deep stopband properties in a miniaturized filter may find potential applications in both microwave and optical-communication systems.

  12. 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.

  13. NOx Sensor for Direct Injection Emission Control

    SciTech Connect

    Betteridge, William J

    2006-02-28

    The Electricore/Delphi team continues to leverage the electrochemical planar sensor technology that has produced stoichiometric planar and wide range oxygen sensors as the basis for development of a NOx sensor. Zirconia cell technology with an integrated heater will provide the foundation for the sensor structure. Proven materials and packaging technology will help to ensure a cost-effective approach to the manufacture of this sensor. The electronics technique and interface is considered to be an area where new strategies need to be employed to produce higher S/N ratios of the NOx signal with emphasis on signal stability over time for robustness and durability Both continuous mode and pulse mode control techniques are being evaluated. Packaging the electronics requires careful design and circuit partitioning so that only the necessary signal conditioning electronics are coupled directly in the wiring harness, while the remainder is situated within the ECM for durability and costs reasons. This task continues to be on hold due to the limitation that the definition of the interface electronics was unavailable until very late in the project. The sense element is based on the amperometric method utilizing integrated alumina and zirconia ceramics. Precious metal electrodes are used to form the integrated heater, the cell electrodes and leads. Inside the actual sense cell structure, it is first necessary to separate NOx from the remaining oxygen constituents of the exhaust, without reducing the NOx. Once separated, the NOx will be measured using a measurement cell. Development or test coupons have been used to facilitate material selection and refinement, cell, diffusion barrier, and chamber development. The sense element currently requires elaborate interconnections. To facilitate a robust durable connection, mechanical and metallurgical connections are under investigation. Materials and process refinements continue to play an important role in the development of the sensor.

  14. 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...

  15. Suitability of nanodiamond nitrogen-vacancy centers for spontaneous emission control experiments

    NASA Astrophysics Data System (ADS)

    Mohtashami, Abbas; Femius Koenderink, A.

    2013-04-01

    Nitrogen-vacancy (NV) centers in diamond are generally recognized as highly promising as indefinitely stable highly efficient single-photon sources. We report an experimental quantification of the brightness, radiative decay rate, nonradiative decay rate and quantum efficiency of single NV centers in diamond nanocrystals. Our experiments show that the commonly observed large spread in fluorescence decay rates of NV centers in nanodiamond is inconsistent with the common explanation of large nanophotonic mode-density variations in the ultra-small high-index crystals at near-unity quantum efficiency. We report that NV centers in 25 nm nanocrystals are essentially insensitive to local density of optical states (LDOS) variations that we induce at a dielectric interface by using liquids to vary the refractive index, and propose that quantum efficiencies in such nanocrystals are widely distributed between 0 and 20%. For single NV centers in larger 100 nm nanocrystals, we show that decay rate changes can be reversibly induced by nanomechanically approaching a mirror to change the LDOS. Using this scanning mirror method, for the first time we report calibrated quantum efficiencies of NV centers, and show that different but nominally identical nanocrystals have widely distributed quantum efficiencies between 10 and 90%. Our measurements imply that nanocrystals that are to be assembled into hybrid photonic structures for cavity QED should first be individually screened to assess fluorescence properties in detail.

  16. 78 FR 49701 - Approval and Promulgation of Implementation Plans; Connecticut; Control of Visible Emissions...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-15

    ...Plans; Connecticut; Control of Visible Emissions, Record Keeping and Monitoring AGENCY...visible and particulate-matter (PM) emissions, record keeping and monitoring regulations...require limitations on visible and PM emissions for stationary sources, and...

  17. 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.

  18. 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.

  19. 40 CFR 63.3555 - How do I determine the outlet THC emissions and add-on control device emission destruction or...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 true How do I determine the outlet THC emissions and add-on control device emission...63.3555 How do I determine the outlet THC emissions and add-on control device emission...this section to determine either the outlet THC emissions or add-on control device...

  20. Control of Several Emissions during Olive Pomace Thermal Degradation

    PubMed Central

    Miranda, Teresa; Nogales, Sergio; Román, Silvia; Montero, Irene; Arranz, José Ignacio; Sepúlveda, Francisco José

    2014-01-01

    Biomass plays an important role as an energy source, being an interesting alternative to fossil fuels due to its environment-friendly and sustainable characteristics. However, due to the exposure of customers to emissions during biomass heating, evolved pollutants should be taken into account and controlled. Changing raw materials or mixing them with another less pollutant biomass could be a suitable step to reduce pollution. This work studied the thermal behaviour of olive pomace, pyrenean oak and their blends under combustion using thermogravimetric analysis. It was possible to monitor the emissions released during the process by coupling mass spectrometry analysis. The experiments were carried out under non-isothermal conditions at the temperature range 25–750 °C and a heating rate of 20 °C·min?1. The following species were analysed: aromatic compounds (benzene and toluene), sulphur emissions (sulphur dioxide), 1,4-dioxin, hydrochloric acid, carbon dioxide and nitrogen oxides. The results indicated that pollutants were mainly evolved in two different stages, which are related to the thermal degradation steps. Thus, depending on the pollutant and raw material composition, different emission profiles were observed. Furthermore, intensity of the emission profiles was related, in some cases, to the composition of the precursor. PMID:25314298

  1. Control of several emissions during olive pomace thermal degradation.

    PubMed

    Miranda, Teresa; Nogales, Sergio; Román, Silvia; Montero, Irene; Arranz, José Ignacio; Sepúlveda, Francisco José

    2014-01-01

    Biomass plays an important role as an energy source, being an interesting alternative to fossil fuels due to its environment-friendly and sustainable characteristics. However, due to the exposure of customers to emissions during biomass heating, evolved pollutants should be taken into account and controlled. Changing raw materials or mixing them with another less pollutant biomass could be a suitable step to reduce pollution. This work studied the thermal behaviour of olive pomace, pyrenean oak and their blends under combustion using thermogravimetric analysis. It was possible to monitor the emissions released during the process by coupling mass spectrometry analysis. The experiments were carried out under non-isothermal conditions at the temperature range 25-750 °C and a heating rate of 20 °C·min?¹. The following species were analysed: aromatic compounds (benzene and toluene), sulphur emissions (sulphur dioxide), 1,4-dioxin, hydrochloric acid, carbon dioxide and nitrogen oxides. The results indicated that pollutants were mainly evolved in two different stages, which are related to the thermal degradation steps. Thus, depending on the pollutant and raw material composition, different emission profiles were observed. Furthermore, intensity of the emission profiles was related, in some cases, to the composition of the precursor. PMID:25314298

  2. Differentiated regulation: a theory with applications to automobile emissions control

    SciTech Connect

    Gruenspecht, H.K.

    1982-01-01

    In part one, a model adapted from growth theory is used to study differentiated regulation. Differentiated regulation is found to be particularly unsuitable for the regulation of industries characterized by slow demand growth, slow physical depreciation, slow technical progress, and limited substitutability in the production process. Since many sectors in which differentiated regulation is commonly used have these properties, changes in regulatory design are apparently in order. The second part of the dissertation evaluates the current US automotive-emissions control program, a differentiated regulatory program, and several alternatives. The 1981 regulatory increment is shown to have increased aggregate hydrocarbon and carbon monoxide emissions in 1981 to 1985 above the level that would have prevailed had the less-stringent 1980 standards been kept in force. Beyond 1985 emissions fall, but by less than forecast using a model that fails investment decisions endogenously. Indeed, the wide disparity in emissions rates among cars presently in the vehicle fleet suggests that strategies that accelerate, rather than retard, replacement of high-emission-rate vehicles are attractive alternatives to the present policy.

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

    PubMed Central

    Yuan, Jian-Jun; Zhu, Pei-Xin; Noda, Daisuke

    2013-01-01

    Summary 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. Dual-Band Plasmonic Enhancement of Ag-NS@SiO 2 on Gain Medium’s Spontaneous Emission

    Microsoft Academic Search

    Jiunn-Woei Liaw; Chuan-Li Liu; Mao-Kuen Kuo

    We present a theoretical study on plasmonic enhancement of molecular fluorescence near a nanocomposite, Ag nanoshell (Ag-NS)\\u000a coated by a gain medium of molecule-doped SiO2 layer. We use an average enhancement factor (AEF), which considers contributions from all possible orientations and locations\\u000a of molecules in the silica layer to estimate the overall performance of Ag-NS@SiO2 at specific excitation and emission

  5. 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.

  6. Nitrogen Isotopic Composition of Coal-Fired Power Plant NOx: Influence of Emission Controls and Implications for Global Emission

    E-print Network

    Elliott, Emily M.

    Nitrogen Isotopic Composition of Coal-Fired Power Plant NOx: Influence of Emission Controls this, a novel method for collection and isotopic analysis of coal-fired stack NOx emission samples-5 Several technologies are available for use in reducing NOx emissions generated from fossil fuel combustion

  7. Spray Charging and Trapping Scrubber for Fugitive Particle Emission Control

    Microsoft Academic Search

    Shui-Chow Yung; Seymour Calvert; Dennis C. Drehmel

    1980-01-01

    The control of fugitive process emissions (FPE) with Spray Charging and Trapping (SCAT) scrubber was evaluated both theoretically and experimentally. The SCAT uses air curtain and\\/or jets to contain, convey, and divert the FPE into a charged spray scrubber.Experiments were performed on an 8000 cfm bench-scale spray scrubber to verify the theory and feasibility of collecting fugitive particles with charged

  8. Rotary Cement Kiln Control for Reducing NOx Emissions to Atmosphere

    Microsoft Academic Search

    Fragiskos A. Batzias

    2006-01-01

    A logic procedure, including 12 alternatives within 32 activities and 13 decision nodes has been designed\\/developed\\/implemented for the rotary cement kiln control aiming at reducing NOx emissions to atmosphere. The hierarchy of alternatives was evaluated through simple and top-down Kendall's coefficients of concordance, proved to be of statistical significance. An implementation is presented in the case of fuel substitution including

  9. 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)...

  10. U.S. will require glycol dehydrator emission control

    SciTech Connect

    Sivalls, C.R. [Sivalls, Inc., Odessa, TX (United States)

    1995-11-01

    Recent or proposed changes in federal an state clean air laws and regulations will affect the operation of glycol dehydration units used to remove water vapor from natural gas. These laws and regulations will limit the amount of aromatic hydrocarbons, such as benzene, toluene, ethyl benzene and xylene (BTEX) and volatile organic compounds (VOCs), that may be emitted into their from the glycol regenerator still vent. This article presents an overview of new laws and regulations, as well as process control systems that may be used to control and reduce the BTEX and VOC emissions. Flare, incineration units, aerial coolers, recycle units and the efficient R-BTEX process are described.

  11. Spontaneous and controllable activation of suicide gene expression driven by the stress-inducible grp78 promoter resulting in eradication of sizable human tumors.

    PubMed

    Dong, Dezheng; Dubeau, Louis; Bading, James; Nguyen, Khoi; Luna, Marian; Yu, Hong; Gazit-Bornstein, Gadi; Gordon, Erlinda M; Gomer, Charles; Hall, Frederick L; Gambhir, Sanjiv S; Lee, Amy S

    2004-06-01

    GRP78 is a stress-inducible chaperone protein with antiapoptotic properties that is overexpressed in transformed cells and cells under glucose starvation, acidosis, and hypoxic conditions that persist in poorly vascularized tumors. Previously we demonstrated that the Grp78 promoter is able to eradicate tumors using murine cells in immunocompetent models by driving expression of the HSV-tk suicide gene. Here, through the use of positron emission tomography (PET) imaging, we provide direct evidence of spontaneous in vivo activation of the HSV-tk suicide gene driven by the Grp78 promoter in growing tumors and its activation by photodynamic therapy (PDT) in a controlled manner. In this report, we evaluated whether this promoter can be applied to human cancer therapy. We observed that the Grp78 promoter, in the context of a retroviral vector, was highly activated by stress and PDT in three different types of human breast carcinomas independent of estrogen receptor and p53. Complete regression of sizable human tumors was observed after prodrug ganciclovir treatment of the xenografts in immunodeficient mice. In addition, the Grp78 promoter-driven suicide gene is strongly expressed in a variety of human tumors, including human osteosarcoma. In contrast, the activity of the murine leukemia virus (MuLV) long-terminal repeat (LTR) promoter varied greatly in different human breast carcinoma cell lines, and in some cases, stress resulted in partial suppression of the LTR promoter activity. In transgenic mouse models, the Grp78 promoter-driven transgene is largely quiescent in major adult organs but highly active in cancer cells and cancer-associated macrophages, which can diffuse to tumor necrotic sites devoid of vascular supply and facilitate cell-based therapy. Thus, transcriptional control through the use of the Grp78 promoter offers multiple novel approaches for human cancer gene therapy. PMID:15212714

  12. COMBUSTION CONTROL OF PCDD/PCDF EMISSIONS FROM MUNICIPAL WASTE INCINERATORS IN NORTH AMERICA

    EPA Science Inventory

    The paper discusses combustion control of emissions of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) from municipal waste incinerators in North America. New regulations to control air pollution emissions from municipal waste incineration have b...

  13. THE IMPACT OF PARTICULATE EMISSIONS CONTROL ON THE CONTROL OF OTHER MWC AIR EMISSIONS

    EPA Science Inventory

    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 a...

  14. 40 CFR 75.34 - Units with add-on emission controls.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...program for the unit, required by...add-on emission controls during each hour...add-on emission controls has been maintained...as part of each electronic quarterly report...add-on emission control for each missing...applies only to a unit which, as...

  15. 40 CFR 75.34 - Units with add-on emission controls.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...program for the unit, required by...add-on emission controls during each hour...add-on emission controls has been maintained...as part of each electronic quarterly report...add-on emission control for each missing...applies only to a unit which, as...

  16. 40 CFR 75.34 - Units with add-on emission controls.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...program for the unit, required by...add-on emission controls during each hour...add-on emission controls has been maintained...as part of each electronic quarterly report...add-on emission control for each missing...applies only to a unit which, as...

  17. 40 CFR 75.34 - Units with add-on emission controls.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...program for the unit, required by...add-on emission controls during each hour...add-on emission controls has been maintained...as part of each electronic quarterly report...add-on emission control for each missing...applies only to a unit which, as...

  18. Practical primer on design of electric arc furnace emission control systems

    Microsoft Academic Search

    P. G. A. Brand; R. W. Manten

    1994-01-01

    The paper will cover the methodology for designing environmentally acceptable and cost-effective emission control systems in modern electric arc furnace meltshops. Fundamental requirements for effective direct evacuation control (DEC) of electric and ladle furnace melting operations and canopy\\/local hood control of secondary emissions from electric arc furnace charging and tapping emissions will be addressed. The following topics will be included:

  19. 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.

  20. 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

  1. 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

  2. Synthetic IR signature control using emissivity enhancement techniques

    NASA Astrophysics Data System (ADS)

    Malyutenko, Volodymyr K.; Malyutenko, Oleg Y.; Bogatyrenko, Vyacheslav V.; Chyrchyk, Sergiy V.; Kircher, James R.; Murrer, Robert L.; Snyder, Donald R.

    2004-08-01

    In this report, we show both theoretically and experimentally how the IR signature of a semiconductor scene (with band gap energy Eg) can be monitored through contactless emissivity control even if this scene thermometric temperature is kept constant. More specifically, we show how a scene emissivity in the spectral band beyond the fundamental absorption range (?2 < Eg / h, 3 to 5 ?m and 8 to 12 ?m transparency windows) can be dynamically (frame frequency > 20 kHz) monitored by a shorter wavelength photo excitation of non-equilibrium charge carriers (?1 > Eg/h, "visible range"). Experimental tests performed on Si and Ge scenes (300 < T < 600 K), demonstrate optically generated cold and hot images and, what is more important, negligible temperature contrast between an object and a background (Stealth effect in IR).

  3. CONTROL OF AIR EMISSIONS FROM MOLYBDENUM ROASTING. VOLUME 1. EMISSIONS CHARACTERIZATION AND PARTICULATE CONTROL

    EPA Science Inventory

    The primary objective of this project was to evaluate a baghouse employing Teflon coated fabric bags for particulate recovery and control. This system was of great interest because of the corrosion resistance of Teflon coated fabric filters and this unique application in the nonf...

  4. Far-infrared amplified spontaneous emission and collisional energy transfer between the E0_g^ + (3P2) and D0_u^ + (3P2) ion-pair states of I2

    NASA Astrophysics Data System (ADS)

    Hoshino, Shoma; Araki, Mitsunori; Tsukiyama, Koichi

    2014-03-01

    We report direct observation of far-infrared amplified spontaneous emission from the E0_g^ + (3P2) (vE = 0 - 3) ion-pair state of I2 by using an optical-optical double resonance technique with the B 3?u (0_u^ +) (vB = 19) valence state as the intermediate state. The directional far-infrared emission detected in the wavelength range from 19 to 28 ?m was assigned to the vibronic transitions from the E0_g^ + (3P2) ion-pair state to the D0_u^ + (3P2) ion-pair state. The subsequent UV fluorescence from the D0_u^ + (3P2) state was also observed, which consists not only from the vibrational levels populated by the amplified spontaneous emission but also from those populated by collisional energy transfer. Analyses of the vibrational distribution in the D0_u^ + (3P2) state revealed that the population transfer through the amplified spontaneous emission was dominant under our experimental conditions.

  5. Start-up and saturation in self-amplified spontaneous emission free-electron lasers using a time-independent analysis.

    PubMed

    Kumar, Vinit; Krishnagopal, Srinivas

    2002-01-01

    Numerical simulation of self-amplified spontaneous emission (SASE) in free-electron lasers (FELs) is typically performed using time-dependent computer codes, which take large CPU time and require large memory. Recently, Yu [Phys. Rev. E 58, 4991 (1998)] has shown that one can even use a time-independent code for this purpose (where the requirement on CPU time and memory is significantly reduced) by modifying it to include multiple phase-space buckets and using a scaling relation between the output power and the number of simulation particles, which is valid only in the linear regime. In this paper, we take a fresh look at the problem and show that incorporating multiple buckets in TDA3D is not needed to simulate the SASE process. We give a new interpretation of time-independent simulations of the SASE process and present detailed justification for using a single-frequency steady-state simulation code for the study of evolution of shot noise. We further extend the simulation studies to the nonlinear regime by modifying the code TDA3D to take the incoherent input power. We use this technique to study the start-up and saturation of the TTF-II FEL at DESY and discuss the results. PMID:11800800

  6. Propagation of a strong x-ray pulse: Pulse compression, stimulated Raman scattering, amplified spontaneous emission, lasing without inversion, and four-wave mixing

    SciTech Connect

    Sun Yuping; Wang Chuankui [College of Physics and Electronics, Shandong Normal University, 250014 Jinan (China); Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, S-10691 Stockholm (Sweden); Liu Jicai; Gel'mukhanov, Faris [Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, S-10691 Stockholm (Sweden)

    2010-01-15

    We study the compression of strong x-ray pulses from x-ray free-electron lasers (XFELs) propagating through the resonant medium of atomic argon. The simulations are based on the three-level model with the frequency of the incident x-ray pulse tuned in the 2p{sub 3/2}-4s resonance. The pulse propagation is accompanied by the self-seeded stimulated resonant Raman scattering (SRRS). The SRRS starts from two channels of amplified spontaneous emission (ASE), 4s-2p{sub 3/2} and 3s-2p{sub 3/2}, which form the extensive ringing pattern and widen the power spectrum. The produced seed field triggers the Stokes ASE channel 3s-2p{sub 3/2}. The population inversion is quenched for longer propagation distances where the ASE is followed by the lasing without inversion (LWI), which amplifies the Stokes component. Both ASE and LWI reshape the input pulse: The compressed front part of the pulse (up to 100 as) is followed by the long tail of the ringing and beating between the pump and Stokes frequencies. The pump pulse also generates weaker Stokes and anti-Stokes fields caused by four-wave mixing. These four spectral bands have fine structures caused by the dynamical Stark effect. A slowdown of the XFEL pulse up to 78% of the speed of light in vacuum is found because of a large nonlinear refractive index.

  7. Controls on CH4 emissions from a northern peatland

    NASA Astrophysics Data System (ADS)

    Bellisario, L. M.; Bubier, J. L.; Moore, T. R.; Chanton, J. P.

    1999-03-01

    We examined the controls on summer CH4 emission from five sites in a peatland complex near Thompson, Manitoba, Canada, representing a minerotrophic gradient from bog to rich fen at wet sites, where the water table positions ranged from -10 to -1 cm. Average CH4 flux, determined by static chambers on collars, ranged from 22 to 239 mg CH4-C m-2 d-1 and was related to peat temperature. There was an inverse relationship between water table position and CH4 flux: higher water tables led to smaller fluxes. The determination of anaerobic CH4 production and aerobic CH4 consumption potentials in laboratory incubations of peat samples was unable to explain much of the variation in CH4 flux. Average net ecosystem exchange of CO2 ranged from 1.4 to 2.5 g CO2-C m-2 d-1 and was strongly correlated with CH4 flux; CH4 emission averaged 4% of CO2 uptake. End-of-season sedge biomass was also strongly related to CH4 flux, indicating the important role that vascular plants play in regulating CH4 flux. Determination of isotopic signatures in peat pore water CH4 revealed average ?13C values of between -50 and -73‰ and ?D of between -368 and -388‰. Sites with large CH4 emission rates also had high CO2 exchange rates and enriched ?13C CH4 signatures, suggesting the importance of the acetate fermentation pathway of methanogenesis. Comparison of ?D and ?13C signatures in pore water CH4 revealed a slope shallow enough to suggest that oxidation is not an important overall control on CH4 emissions at these sites, though it appeared to be important at one site. Analysis of 14C in pore water CH4 showed that most of the CH4 was of recent origin with percent of modern carbon values of between 112 and 128%. The study has shown the importance of vascular plant activities in controlling CH4 emissions from these wetland sites through influences on the availability of fresh plant material for methanogenesis, rhizospheric oxidation, and plant transport of CH4.

  8. Autonomic control of the heart is altered in Sprague-Dawley rats with spontaneous hydronephrosis.

    PubMed

    Arnold, Amy C; Shaltout, Hossam A; Gilliam-Davis, Shea; Kock, Nancy D; Diz, Debra I

    2011-06-01

    The renal medulla plays an important role in cardiovascular regulation, through interactions with the autonomic nervous system. Hydronephrosis is characterized by substantial loss of renal medullary tissue. However, whether alterations in autonomic control of the heart are observed in this condition is unknown. Thus we assessed resting hemodynamics and baroreflex sensitivity (BRS) for control of heart rate in urethane/chloralose-anesthetized Sprague-Dawley rats with normal or hydronephrotic kidneys. While resting arterial pressure was similar, heart rate was higher in rats with hydronephrosis (290 ± 12 normal vs. 344 ± 11 mild/moderate vs. 355 ± 13 beats/min severe; P < 0.05). The evoked BRS to increases, but not decreases, in pressure was lower in hydronephrotic rats (1.06 ± 0.06 normal vs. 0.72 ± 0.10 mild/moderate vs. 0.63 ± 0.07 ms/mmHg severe; P < 0.05). Spectral analysis methods confirmed reduced parasympathetic function in hydronephrosis, with no differences in measures of indirect sympathetic activity among conditions. As a secondary aim, we investigated whether autonomic dysfunction in hydronephrosis is associated with activation of the renin-angiotensin system (RAS). There were no differences in circulating angiotensin peptides among conditions, suggesting that the impaired autonomic function in hydronephrosis is independent of peripheral RAS activation. A possible site for angiotensin II-mediated BRS impairment is the solitary tract nucleus (NTS). In normal and mild/moderate hydronephrotic rats, NTS administration of the angiotensin II type 1 receptor antagonist candesartan significantly improved the BRS, suggesting that angiotensin II provides tonic suppression to the baroreflex. In contrast, angiotensin II blockade produced no significant effect in severe hydronephrosis, indicating that at least within the NTS baroreflex suppression in these animals is independent of angiotensin II. PMID:21460193

  9. Autonomic control of the heart is altered in Sprague-Dawley rats with spontaneous hydronephrosis

    PubMed Central

    Arnold, Amy C.; Shaltout, Hossam A.; Gilliam-Davis, Shea; Kock, Nancy D.

    2011-01-01

    The renal medulla plays an important role in cardiovascular regulation, through interactions with the autonomic nervous system. Hydronephrosis is characterized by substantial loss of renal medullary tissue. However, whether alterations in autonomic control of the heart are observed in this condition is unknown. Thus we assessed resting hemodynamics and baroreflex sensitivity (BRS) for control of heart rate in urethane/chloralose-anesthetized Sprague-Dawley rats with normal or hydronephrotic kidneys. While resting arterial pressure was similar, heart rate was higher in rats with hydronephrosis (290 ± 12 normal vs. 344 ± 11 mild/moderate vs. 355 ± 13 beats/min severe; P < 0.05). The evoked BRS to increases, but not decreases, in pressure was lower in hydronephrotic rats (1.06 ± 0.06 normal vs. 0.72 ± 0.10 mild/moderate vs. 0.63 ± 0.07 ms/mmHg severe; P < 0.05). Spectral analysis methods confirmed reduced parasympathetic function in hydronephrosis, with no differences in measures of indirect sympathetic activity among conditions. As a secondary aim, we investigated whether autonomic dysfunction in hydronephrosis is associated with activation of the renin-angiotensin system (RAS). There were no differences in circulating angiotensin peptides among conditions, suggesting that the impaired autonomic function in hydronephrosis is independent of peripheral RAS activation. A possible site for angiotensin II-mediated BRS impairment is the solitary tract nucleus (NTS). In normal and mild/moderate hydronephrotic rats, NTS administration of the angiotensin II type 1 receptor antagonist candesartan significantly improved the BRS, suggesting that angiotensin II provides tonic suppression to the baroreflex. In contrast, angiotensin II blockade produced no significant effect in severe hydronephrosis, indicating that at least within the NTS baroreflex suppression in these animals is independent of angiotensin II. PMID:21460193

  10. 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.

  11. Jovian longitudinal control of Io-related radio emissions

    NASA Technical Reports Server (NTRS)

    Dessler, A. J.; Hill, T. W.

    1979-01-01

    A theoretical model is proposed to explain the control of Io-related radio emissions by Jupiter's rotational phase. The model is based on the hypothesis that the radio emissions are generated by Birkeland currents flowing between Io and the Jovian ionosphere. Specifically, it is suggested that the precipitation of radiation-belt electrons within a certain range of Jovian longitudes produces a restricted region of enhanced ionization and correspondingly enhanced conductivity in Jupiter's ionosphere and that the Io-Jupiter Birkeland current and the associated radio emissions are dramatically increased when Io's flux tube encounters this sector of enhanced ionization in Jupiter's ionosphere. The magnitude of the current is found to be about 100,000 A at most Jovian longitudes because of ionospheric resistance. It is estimated that within the favored longitudinal sector electron precipitation produces an enhancement of this current by one to three orders of magnitude. The model predictions are compared with observations made during the Pioneer 10 and 11 flybys, and satisfactory agreement is obtained.

  12. Optimizing the mix of strategies for control of vehicular emissions

    SciTech Connect

    Lejano, R.P. [Montgomery Watson, Pasadena, CA (United States)] [Montgomery Watson, Pasadena, CA (United States); Ayala, P.M. [California Air Resources Board, El Monte, CA (United States)] [California Air Resources Board, El Monte, CA (United States); Gonzales, E.A. [Environmental Management Bureau, Quezon City (Philippines)] [Environmental Management Bureau, Quezon City (Philippines)

    1997-01-01

    A number of strategies for the control of vehicular emissions are being considered by the Philippine government to address Metropolitan Manila`s air quality problem. An analytical tool is needed for optimizing criteria pollutant reductions given the budgetary constraints. The simplest approach is to take costs and pollutant removals to be linear with each strategy`s scale of activity, and this is readily solved as a linear programming problem. Another approach is to use a dynamic system of weights which shift with progressive improvements in pollutant emissions. The two approaches yield somewhat different results, suggesting the sensitivity of the solution to the assumed weights. The study also illustrates the importance of a sound methodology for evaluating priorities given to different air quality goals. One such methodology may involve a polling of expert panels and the public to gain insight into the relative importance given to competing emissions reduction goals. An informal polling of resource agency staff was conducted and discussed in this paper. The authors take the position that proper planning involves tracing intermediate steps to the final outcome and not just focusing on the latter. 17 refs., 1 fig., 8 tabs.

  13. Controlling mercury emissions from coal-fired power plants

    SciTech Connect

    Chang, R. [Electric Power Research Institute, Palo Alto, CA (United States)

    2009-07-15

    Increasingly stringent US federal and state limits on mercury emissions form coal-fired power plants demand optimal mercury control technologies. This article summarises the successful removal of mercury emissions achieved with activated carbon injection and boiler bromide addition, technologies nearing commercial readiness, as well as several novel control concepts currently under development. It also discusses some of the issues standing in the way of confident performance and cost predictions. In testing conducted on western coal-fired units with fabric filters or TOXECON to date, ACI has generally achieved mercury removal rates > 90%. At units with ESPs, similar performance requires brominated ACI. Alternatively, units firing western coals can use boiler bromide addition to increase flue gas mercury oxidation and downstream capture in a wet scrubber, or to enhance mercury removal by ACI. At eastern bituminous fired units with ESPs, ACI is not as effective, largely due to SO{sub 3} resulting from the high sulfur content of the coal or the use of SO{sub 3} flue gas conditioning to improve ESP performance. 7 refs., 3 figs.

  14. 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

  15. LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL

    SciTech Connect

    Don Augenstein; Ramin Yazdani; Rick Moore; Michelle Byars; Jeff Kieffer; Professor Morton Barlaz; Rinav Mehta

    2000-02-26

    Controlled landfilling is an approach to manage solid waste landfills, so as to rapidly complete methane generation, while maximizing gas capture and minimizing the usual emissions of methane to the atmosphere. With controlled landfilling, methane generation is accelerated to more rapid and earlier completion to full potential by improving conditions (principally moisture, but also temperature) to optimize biological processes occurring within the landfill. Gas is contained through use of surface membrane cover. Gas is captured via porous layers, under the cover, operated at slight vacuum. A field demonstration project has been ongoing under NETL sponsorship for the past several years near Davis, CA. Results have been extremely encouraging. Two major benefits of the technology are reduction of landfill methane emissions to minuscule levels, and the recovery of greater amounts of landfill methane energy in much shorter times, more predictably, than with conventional landfill practice. With the large amount of US landfill methane generated, and greenhouse potency of methane, better landfill methane control can play a substantial role both in reduction of US greenhouse gas emissions and in US renewable energy. The work described in this report, to demonstrate and advance this technology, has used two demonstration-scale cells of size (8000 metric tons [tonnes]), sufficient to replicate many heat and compaction characteristics of larger ''full-scale'' landfills. An enhanced demonstration cell has received moisture supplementation to field capacity. This is the maximum moisture waste can hold while still limiting liquid drainage rate to minimal and safely manageable levels. The enhanced landfill module was compared to a parallel control landfill module receiving no moisture additions. Gas recovery has continued for a period of over 4 years. It is quite encouraging that the enhanced cell methane recovery has been close to 10-fold that experienced with conventional landfills. This is the highest methane recovery rate per unit waste, and thus progress toward stabilization, documented anywhere for such a large waste mass. This high recovery rate is attributed to moisture, and elevated temperature attained inexpensively during startup. Economic analyses performed under Phase I of this NETL contract indicate ''greenhouse cost effectiveness'' to be excellent. Other benefits include substantial waste volume loss (over 30%) which translates to extended landfill life. Other environmental benefits include rapidly improved quality and stabilization (lowered pollutant levels) in liquid leachate which drains from the waste.

  16. Methane emissions from process equipment at natural gas production sites in the United States: pneumatic controllers.

    PubMed

    Allen, David T; Pacsi, Adam P; Sullivan, David W; Zavala-Araiza, Daniel; Harrison, Matthew; Keen, Kindal; Fraser, Matthew P; Daniel Hill, A; Sawyer, Robert F; Seinfeld, John H

    2015-01-01

    Emissions from 377 gas actuated (pneumatic) controllers were measured at natural gas production sites and a small number of oil production sites, throughout the United States. A small subset of the devices (19%), with whole gas emission rates in excess of 6 standard cubic feet per hour (scf/h), accounted for 95% of emissions. More than half of the controllers recorded emissions of 0.001 scf/h or less during 15 min of measurement. Pneumatic controllers in level control applications on separators and in compressor applications had higher emission rates than controllers in other types of applications. Regional differences in emissions were observed, with the lowest emissions measured in the Rocky Mountains and the highest emissions in the Gulf Coast. Average methane emissions per controller reported in this work are 17% higher than the average emissions per controller in the 2012 EPA greenhouse gas national emission inventory (2012 GHG NEI, released in 2014); the average of 2.7 controllers per well observed in this work is higher than the 1.0 controllers per well reported in the 2012 GHG NEI. PMID:25488196

  17. 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.

  18. SURVEY OF EMISSIONS CONTROL AND COMBUSTION EQUIPMENT DATA IN INDUSTRIAL PROCESS HEATING

    EPA Science Inventory

    The report discusses the interaction between present and potential energy conservation measures and emission programs in various industries. Where energy conservation goals conflicted with emission control goals, the problems were assessed. Based on these assessments, research an...

  19. CONTROL OF INDUSTRIAL VOC (VOLATILE ORGANIC COMPOUND) EMISSIONS BY CATALYTIC INCINERATION. VOLUME 9. QUALITY ASSURANCE

    EPA Science Inventory

    Radian Corporation, under contract to the U.S. Environmental Protection Agency, performed site selection, test plan development, and performance tests of catalytic incinerators used for volatile organic compound (VOC) emissions control at industrial sites. VOC emissions are of co...

  20. 78 FR 5346 - Approval and Promulgation of Implementation Plans; State of Missouri; Control of Sulfur Emissions...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-25

    ...Promulgation of Implementation Plans; State of Missouri; Control of Sulfur Emissions From Stationary Boilers AGENCY: Environmental Protection... 2.5 ) in the St. Louis nonattainment area by limiting sulfur dioxide (SO 2 ) emissions (a precursor pollutant to...

  1. 40 CFR 1060.104 - What running loss emission control requirements apply?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...that your system meets applicable running loss standards in California. (c) If you are subject to both running loss and diurnal emission standards, use good engineering judgment to ensure that the emission controls are...

  2. Plasmonic control of light emission for enhanced efficiency and beam shaping

    NASA Astrophysics Data System (ADS)

    DiMaria, Jeffrey V.

    InGaN alloys and related quantum structures are of great technological importance for the development of visible light emitting devices, motivated by a wide range of applications, particularly solid-state lighting. The InxGa1--xN material system provides continuous emission tuning from the ultraviolet across the visible spectrum by changing the In content. InGaN/GaN quantum wells (QW) also provide an efficient medium for electroluminescence for use as light emitting diodes. It is well known, however, that increasing the In content degrades the internal quantum efficiency of these devices, particularly in the green region of the spectrum. These limitations must be overcome before efficient all-solid-state lighting can be developed beyond the blue-green region using this material system. Recently, the application of plasmonic excitations supported by metallic nanostructures has emerged as a promising approach to address this issue. In this work, metallic nanoparticles (NPs) and nanostructures that support plasmonic modes are engineered to increase the local density of states of the electromagnetic field that overlaps the QW region. This leads to an enhancement of the spontaneous emission rate of the QW region mediated by direct coupling into the plasmonic modes of the nanostructure. Energy stored in these modes can then scatter efficiently into free-space radiation, thereby enhancing the light output intensity. The first section of this thesis concerns the enhancement of InGaN/GaN QW light emission by utilizing localized surface plasmon resonances (LSPRs) and lattice surface modes of metal NP arrays. This work comprises a detailed study of the effect of geometry variations of Ag NPs on the LSPR wavelength, and the subsequent demonstration of photoluminescence intensity enhancement by Ag NPs in the vicinity of InGaN multiple QWs. The second section of this thesis concerns the far-field control of QW emission utilizing metallic nanostructures that support plasmonic excitations. This includes a study of the dispersion and competing effects of a metallic NP-film system, and the demonstration of beam collimation and unidirectional diffraction utilizing a similar geometry. These results may find novel applications in the emerging field of solid-state smart lighting.

  3. DNA Repair Deficiency as a Susceptibility Marker for Spontaneous Lymphoma in Golden Retriever Dogs: A Case-Control Study

    PubMed Central

    Thamm, Douglas H.; Grunerud, Kristen K.; Rose, Barbara J.; Vail, David M.; Bailey, Susan M.

    2013-01-01

    There is accumulating evidence that an individual’s inability to accurately repair DNA damage in a timely fashion may in part dictate a predisposition to cancer. Dogs spontaneously develop lymphoproliferative diseases such as lymphoma, with the golden retriever (GR) breed being at especially high risk. Mechanisms underlying such breed susceptibility are largely unknown; however, studies of heritable cancer predisposition in dogs may be much more straightforward than similar studies in humans, owing to a high degree of inbreeding and more limited genetic heterogeneity. Here, we conducted a pilot study with 21 GR with lymphoma, 20 age-matched healthy GR and 20 age-matched healthy mixed-breed dogs (MBD) to evaluate DNA repair capability following exposure to either ionizing radiation (IR) or the chemical mutagen bleomycin. Inter-individual variation in DNA repair capacity was evaluated in stimulated canine lymphoctyes exposed in vitro utilizing the G2 chromosomal radiosensitivity assay to quantify clastogen-induced chromatid-type aberrations (gaps and breaks). Golden retrievers with lymphoma demonstrated elevated sensitivity to induction of chromosome damage following either challenge compared to either healthy GR or MBD at multiple doses and time points. Using the 75th percentile of chromatid breaks per 1,000 chromosomes in the MBD population at 4 hours post 1.0 Gy IR exposure as a benchmark to compare cases and controls, GR with lymphoma were more likely than healthy GR to be classified as “sensitive” (odds ratio = 21.2, 95% confidence interval 2.3-195.8). Furthermore, our preliminary findings imply individual (rather than breed) susceptibility, and suggest that deficiencies in heritable factors related to DNA repair capabilities may be involved in the development of canine lymphoma. These studies set the stage for larger confirmatory studies, as well as candidate-based approaches to probe specific genetic susceptibility factors. PMID:23935952

  4. 75 FR 7426 - Tier 2 Light-Duty Vehicle and Light-Duty Truck Emission Standards and Gasoline Sulfur Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-19

    ...Light-Duty Truck Emission Standards and Gasoline Sulfur Control Requirements...2 Motor Vehicle Emissions Standards and Gasoline Sulfur Control Requirements...sulfur in their gasoline. The Tier 2 program...reduce new vehicle emissions, primarily...

  5. Plasma control using neural network and optical emission spectroscopy

    SciTech Connect

    Kim, Byungwhan; Bae, Jung Ki; Hong, Wan-Shick [Department of Electronic Engineering, Bio Engineering Research Institute, Sejong University, 98, Kunja-Dong, Kwangjin-Ku, Seoul 143-747 (Korea, Republic of)

    2005-03-01

    Due to high sensitivity to process parameters, plasma processes should be tightly controlled. For plasma control, a predictive model was constructed using a neural network and optical emission spectroscopy (OES). Principal component analysis (PCA) was used to reduce OES dimensionality. This approach was applied to an oxide plasma etching conducted in a CHF{sub 3}/CF{sub 4} magnetically enhanced reactive ion plasma. The etch process was systematically characterized by means of a statistical experimental design. Three etch outputs (etch rate, profile angle, and etch rate nonuniformity) were modeled using three different approaches, including conventional, OES, and PCA-OES models. For all etch outputs, OES models demonstrated improved predictions over the conventional or PCA-OES models. Compared to conventional models, OES models yielded an improvement of more than 25% in modeling profile angle and etch rate nonuniformtiy. More than 40% improvement over PCA-OES model was achieved in modeling etch rate and profile angle. These results demonstrate that nonreduced in situ data are more beneficial than reduced one in constructing plasma control model.

  6. Application of microturbines to control emissions from associated gas

    SciTech Connect

    Schmidt, Darren D.

    2013-04-16

    A system for controlling the emission of associated gas produced from a reservoir. In an embodiment, the system comprises a gas compressor including a gas inlet in fluid communication with an associated gas source and a gas outlet. The gas compressor adjusts the pressure of the associated gas to produce a pressure-regulated associated gas. In addition, the system comprises a gas cleaner including a gas inlet in fluid communication with the outlet of the gas compressor, a fuel gas outlet, and a waste product outlet. The gas cleaner separates at least a portion of the sulfur and the water from the associated gas to produce a fuel gas. Further, the system comprises a gas turbine including a fuel gas inlet in fluid communication with the fuel gas outlet of the gas cleaner and an air inlet. Still further, the system comprises a choke in fluid communication with the air inlet.

  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. 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

  9. Use of SNCR to control emissions of oxides of nitrogen from cement plants

    Microsoft Academic Search

    Joe Horton; A. Linero; F. MacGregor Miller

    2006-01-01

    As air pollution environmental requirements for Portland cement manufacturing facilities become ever more demanding, and opportunities for controlling emissions of oxides of nitrogen are restricted by other emission limitations (e.g., for carbon monoxide and sulfur oxides), the cement manufacturer is faced with the need to control NOx, while continuing to control the other pollutants. There are a number of methods

  10. 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

  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. 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.

  13. Fine particle (2.5 microns) emissions: regulations, measurement, and control

    SciTech Connect

    John D. McKenna; James H. Turner; James P. McKenna, Jr.

    2008-09-15

    Contents: Introduction; Health effects; Air monitoring; Emission control methods - fabric filter/baghouses, electrostatic precipitators, wet scrubbers; Environmental technology verification and baghouse filtration products; Cost considerations; and Nanoparticulates.

  14. Modeling and control of airport departure processes for emissions reduction

    E-print Network

    Simaiakis, Ioannis

    2009-01-01

    Taxiing aircraft contribute significantly to the fuel burn and emissions at airports. This thesis investigates the possibility of reducing fuel burn and emissions from surface operations through a reduction of the taxi ...

  15. 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

  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. Three-Dimensional Composite Nanostructures for Lean NOx Emission Control

    SciTech Connect

    Gao, Pu-Xian

    2013-07-31

    This final report to the Department of Energy (DOE) and National Energy Technology Laboratory (NETL) for DE-EE0000210 covers the period from October 1, 2009 to July 31, 2013. Under this project, DOE awarded UConn about $1,248,242 to conduct the research and development on a new class of 3D composite nanostructure based catalysts for lean NOx emission control. Much of the material presented here has already been submitted to DOE/NETL in quarterly technical reports. In this project, through a scalable solution process, we have successfully fabricated a new class of catalytic reactors, i.e., the composite nanostructure array (nano-array) based catalytic converters. These nanocatalysts, distinct from traditional powder washcoat based catalytic converters, directly integrate monolithic substrates together with nanostructures with well-defined size and shape during the scalable hydrothermal process. The new monolithic nanocatalysts are demonstrated to be able to save raw materials including Pt-group metals and support metal oxides by an order of magnitude, while perform well at various oxidation (e.g., CO oxidation and NO oxidation) and reduction reactions (H{sub 2} reduction of NOx) involved in the lean NOx emissions. The size, shape and arrangement of the composite nanostructures within the monolithic substrates are found to be the key in enabling the drastically reduced materials usage while maintaining the good catalytic reactivity in the enabled devices. The further understanding of the reaction kinetics associated with the unique mass transport and surface chemistry behind is needed for further optimizing the design and fabrication of good nanostructure array based catalytic converters. On the other hand, the high temperature stability, hydrothermal aging stability, as well as S-poisoning resistance have been investigated in this project on the nanocatalysts, which revealed promising results toward good chemical and mechanical robustness, as well as S-poisoning resistance. Further investigation is needed for unraveling the understanding, design and selection principles of this new class of nanostructure based monolithic catalysts.

  18. SETTING PRIORITIES FOR CONTROL OF FUGITIVE PARTICULATE EMISSIONS FROM OPEN SOURCES

    EPA Science Inventory

    The report describes setting priorities for controlling fugitive particulate emissions. Emission rate estimates of suspended particulates from open sources in the U.S. were obtained from emission factors and source extents in the literature. Major open sources, with their estimat...

  19. Control of NO\\/sub x\\/ and SOâ emissions by gas reburning-sorbent injection technology

    Microsoft Academic Search

    W. Bartok; B. A. Folsom

    1987-01-01

    Emissions of oxides of sulfur and nitrogen are thought to be responsible for acid rain deposition. A large number of existing pre-NSPS electric utility boilers fired with Midwestern and Eastern coals would be affected if acid rain control legislation is promulgated. To allow such boilers to meet potential emissions regulations with fuel flexibility and good operability, cost effective retrofit emission

  20. Burner technology bulletin: control of NO\\/sub x\\/ emissions from residential gas appliances

    Microsoft Academic Search

    M. J. Murphy; A. A. Putnam

    1985-01-01

    The bulletin summarizes the status of technology on NOx control for reference by appliance manufacturers. It is intended as a primer for engineering personnel. The bulletin contains information on: the origin of NO and NO2 emissions, typical NO and NO2 emissions from various types of gas appliances, effects of combustion variables on NOx emissions, methods of NOx reduction, test methods

  1. Sulfation of ceria-zirconia model automotive emissions control catalysts

    NASA Astrophysics Data System (ADS)

    Nelson, Alan Edwin

    Cerium-zirconium mixed metal oxides are used in automotive emissions control catalysts to regulate the partial pressure of oxygen near the catalyst surface. The near surface oxygen partial pressure is regulated through transfer of atomic oxygen from the ceria-zirconia solid matrix to the platinum group metals to form metal oxides capable of oxidizing carbon monoxide and unburned hydrocarbons. Although the addition of zirconium in the cubic lattice of ceria increases the oxygen storage capacity and thermal stability of the ceria matrix, the cerium-zirconium oxide system remains particularly susceptible to deactivation from sulfur compounds. While the overall effect of sulfur on these systems is understood (partially irreversible deactivation), the fundamental and molecular interaction of sulfur with ceria-zirconia remains a challenging problem. Ceria-zirconia metal oxide solid solutions have been prepared through co-precipitation with nitrate precursors. The prepared powders were calcined and subsequently formed into planer wafers and characterized for chemical and physical attributes. The prepared samples were subsequently exposed to a sulfur dioxide based environment and characterized with spectroscopic techniques to characterize the extent of sulfation and the nature of surface sulfur species. The extent of sulfation of the model ceria-zirconia systems was characterized with Auger electron spectroscopy (AES) prior to and after treatment in a microreactor. Strong dependencies were observed between the atomic ratio of ceria to zirconia and the extent of sulfation. In addition, the partial pressure of sulfur dioxide during treatments also correlated to the extent of sulfation, while temperature only slightly effected the extent of sulfation. The AES data suggests the gas phase sulfur dioxide preferentially chemisorbs on surface ceria atoms and the extent of sulfation is heavily dependent on sulfur dioxide concentrations and only slightly dependent on catalyst temperatures, as confirmed by thermal programmed desorption (TPD). While hydrogen exposure indicated slight sulfur removal, exposure to a redox environment or atmosphere nearly eliminated the quantity of chemisorbed surface sulfur. The nature of sulfur removal is attributed to the inherent redox properties of ceria-zirconia systems. The complete analysis provides mechanistic insight into sulfation dependencies and fundamental information regarding sulfur adsorption on ceria-zirconia model automotive emissions control systems.

  2. Assessment of VOC emissions and their control from baker's yeast manufacturing facilities. Final report

    SciTech Connect

    Barker, R.; Williamson, M.

    1992-01-01

    The Environmental Protection Agency's (EPA's) Control Technology Center (CTC) conducted a study to obtain information on the baker's yeast manufacturing industry. Baker's yeast is produced by a fermentation process that generates large quantities of ethanol and acetaldehyde. Currently, 13 facilities produce baker's yeast in the United States. The volatile organic compound (VOC) emission rate from a typical facility is estimated at 82 megagrams per year (90 tons per year). The majority of these emissions occurs in the final trade fermentations. The VOC emission alternatives that were evaluated during the study were process control measures to reduce the formation of VOC emissions as well as wet scrubbers, carbon adsorbers, incinerators, condensers, and biological filters to control VOC emissions. Of these approaches, it appears that process control measures, catalytic incinerators, or a combination of add-on control techniques (e.g., wet scrubbers followed by an incinerator or a biological filter) are the most feasible approaches for controlling yeast process emissions. Based on the results of the study, the control efficiency associated with the add-on control systems is estimated to be 95 to 98 percent. The report contains information on the baker's yeast fermentation process, the number and locations of yeast plants, the potential emissions from the process, and an evaluation of potential emission control options.

  3. 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

  4. 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...

  5. 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...

  6. Synergy between Pollution and Carbon Emissions Control: Comparing China and the U.S.

    E-print Network

    Nam, Kyung-Min

    We estimate the potential synergy between pollution and climate control in the U.S. and China, summarizing the results as emissions cross-elasticities of control. We set a range of NOx and SO2 targets, and record the ...

  7. Estimation of automobile emissions and control strategies in India.

    PubMed

    Nesamani, K S

    2010-03-15

    Rapid, but unplanned urban development and the consequent urban sprawl coupled with economic growth have aggravated auto dependency in India over the last two decades. This has resulted in congestion and pollution in cities. The central and state governments have taken many ameliorative measures to reduce vehicular emissions. However, evolution of scientific methods for emission inventory is crucial. Therefore, an attempt has been made to estimate the emissions (running and start) from on-road vehicles in Chennai using IVE model in this paper. GPS was used to collect driving patterns. The estimated emissions from motor vehicles in Chennai in 2005 were 431, 119, 46, 7, 4575, 29, and 0.41 tons/days respectively for CO, VOC, NO(x), PM, CO(2,) CH(4) and N(2)O. It is observed from the results that air quality in Chennai has degraded. The estimation revealed that two and three-wheelers emitted about 64% of the total CO emissions and heavy-duty vehicles accounted for more than 60% and 36% of the NO(x) and PM emissions respectively. About 19% of total emissions were that of start emissions. It is also estimated that on-road transport contributes about 6637 tons/day CO(2) equivalent in Chennai. This paper has further examined various mitigation options to reduce vehicular emissions. The study has concluded that advanced vehicular technology and augmentation of public transit would have significant impact on reducing vehicular emissions. PMID:20149922

  8. 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.

  9. Neuroendocrine and metabolic effects of general Anaesthesia during spontaneous breathing, controlled breathing, mild Hypoxia, and mild Hypercarbia

    Microsoft Academic Search

    Allen B. Dobkin; Peter H. Byles; John F. Neville

    1966-01-01

    Summary and Conclusions  Serial crossover tests were carried out on 10 to 15 large, trained, male dogs that were moderately deeply anaesthetized for\\u000a 90 minutes, at two-week intervals, with thiopental, Innovar, diethyl ether cyclopropane, chloroform, trichlorethylene, fluroxene,\\u000a halothane, halothane-ether azeotrope, and methoxyflurane. These tests were done under four conditions: spontaneous breathing\\u000a with 50 per cent N2O + 50 per cent O2

  10. 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...

  11. 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...

  12. Engine Tune-up Service. Unit 6: Emission Control Systems. Student Guide. Automotive Mechanics Curriculum.

    ERIC Educational Resources Information Center

    Bacon, E. Miles

    This student guide is for Unit 6, Emission Control Systems, in the Engine Tune-Up Service portion of the Automotive Mechanics Curriculum. It deals with inspecting, testing, and servicing an emission control system. A companion review exercise book and posttests are available separately as CE 031 221-222. An introduction tells how this unit fits…

  13. Engine Tune-up Service. Unit 6: Emission Control Systems. Review Exercise Book. Automotive Mechanics Curriculum.

    ERIC Educational Resources Information Center

    Bacon, E. Miles

    This book of pretests and review exercises is designed to accompany the Engine Tune-Up Service Student Guide for Unit 6, Emission Control Systems, available separately as CE 031 220. Focus of the exercises and pretests is inspecting, testing, and servicing emission control systems. Pretests and performance checklists are provided for each of the…

  14. 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.

  15. Gaseous and particulate emission control on industrial solid waste incinerators using wet scrubbers

    Microsoft Academic Search

    J. D. Brady; J. H. Andros

    1983-01-01

    The type of waste which is burned in a solid waste incinerator dictates whether or not secondary air pollution control equipment will be required and the type of air pollution control equipment which must be used. Both gas phase and particulate emissions are produced by these incinerators. The most common emission is HCl gas produced by the combustion of chlorine

  16. 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...

  17. 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;…

  18. Dual-UEGO Active Catalyst Control for Emissions Reduction: Design and Experimental Validation

    E-print Network

    Grizzle, Jessy W.

    Dual-UEGO Active Catalyst Control for Emissions Reduction: Design and Experimental Validation gasoline engines (that is, homogeneous charge, stoichiometric air-fuel ratio (A/F)), employ a three-way catalytic converter (TWC) to oxidize HC and CO emissions and reduce NOx. Tradi- tionally, the control

  19. Study of gasoline vapor emission controls at small bulk plants. Final report

    Microsoft Academic Search

    R. J. Bryan; W. O. Jacobson; R. R. Saakaida; P. S. Bakshi

    1976-01-01

    The purpose of this report is to provide information to operators of gasoline bulk plants and to air pollution control authorities regarding sources of emissions of hydrocarbon vapors from bulk plants and the effectiveness and costs of available technology for control of these emissions. The study was limited to bulk plants distributing less than 76,000 liters (20,000 gallons) of gasoline

  20. Factors controlling natural VOC emissions in a southeastern US pine forest

    NASA Astrophysics Data System (ADS)

    Kim, Jo-Chun

    A one-year field study was conducted to investigate the control factors of the monoterpene emissions from slash and loblolly pine saplings at the Austin Cary Forest site in Florida. The ?-pinene, camphene, ?-pinene, myrcene, d-limonene, and ?-phellandrene were identified in the emission samples collected from native pine trees. The ?-pinene was the principal (>60%) monoterpene emitted by both slash and loblolly pine saplings. Terpene emission rates in spring were the highest and most volatile for slash pine trees, possibly due to the influences of bud formation and elongation. Loblolly pine emissions, under a similar environmental temperature range, revealed different seasonal patterns of emissions when compared to those for slash pines. Emission rates of monoterpenes from slash and loblolly pine trees were found to depend on temperature, season's change (e.g., bud emissions), tree age, needle surface wetness, and rough handling. It is suggested that the emission control factors besides the environmental temperature should also be taken into account in assessing regional biogenic emissions for compling a worldwide hydrocarbon emission inventory. It is also found that monoterpene emission rates could easily change over a long period of time (e.g., years), and so it is desirable to analyze the emission data based on the short term (e.g., season, month) for reasonable temperature-emission algorithm.

  1. 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.

  2. Sheath structure transition controlled by secondary electron emission

    NASA Astrophysics Data System (ADS)

    Schweigert, I. V.; Langendorf, S. J.; Walker, M. L. R.; Keidar, M.

    2015-04-01

    In particle-in-cell Monte Carlo collision (PIC MCC) simulations and in an experiment we study sheath formation over an emissive floating Al2O3 plate in a direct current discharge plasma at argon gas pressure 10?4 Torr. The discharge glow is maintained by the beam electrons emitted from a negatively biased hot cathode. We observe three types of sheaths near the floating emissive plate and the transition between them is driven by changing the negative bias. The Debye sheath appears at lower voltages, when secondary electron emission is negligible. With increasing applied voltage, secondary electron emission switches on and a first transition to a new sheath type, beam electron emission (BEE), takes place. For the first time we find this specific regime of sheath operation near the floating emissive surface. In this regime, the potential drop over the plate sheath is about four times larger than the temperature of plasma electrons. The virtual cathode appears near the emissive plate and its modification helps to maintain the BEE regime within some voltage range. Further increase of the applied voltage U initiates the second smooth transition to the plasma electron emission sheath regime and the ratio ??s/Te tends to unity with increasing U. The oscillatory behavior of the emissive sheath is analyzed in PIC MCC simulations. A plasmoid of slow electrons is formed near the plate and transported to the bulk plasma periodically with a frequency of about 25 kHz.

  3. Emission Controls Using Different Temperatures of Combustion Air

    PubMed Central

    Holub?ík, Michal; Papu?ík, Štefan

    2014-01-01

    The effort of many manufacturers of heat sources is to achieve the maximum efficiency of energy transformation chemically bound in the fuel to heat. Therefore, it is necessary to streamline the combustion process and minimize the formation of emission during combustion. The paper presents an analysis of the combustion air temperature to the heat performance and emission parameters of burning biomass. In the second part of the paper the impact of different dendromass on formation of emissions in small heat source is evaluated. The measured results show that the regulation of the temperature of the combustion air has an effect on concentration of emissions from the combustion of biomass. PMID:24971376

  4. 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.

  5. 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

  6. 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...

  7. 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...

  8. VOC EMISSION CONTROL TECHNOLOGIES FOR SHIP PAINTING FACILITIES: INDUSTRY CHARACTERIZATION

    EPA Science Inventory

    The U.S. Environmental Protection Agency has the responsibility of reducing the levels of VOC emissions from the nation's stationary and mobile sources. The project was directed at assessing the levels of VOC emissions from ship painting operations with the intent of determining ...

  9. Environmental Control of Isoprene Emission: from Leaf to Canopy Scale 

    E-print Network

    Pegoraro, Emiliano

    , in the long-term, the CO2 inhibition effect for isoprene emission became a permanent feature for plants growing under elevated [CO2]. Again, isoprene emission was less responsive to drought than photosynthesis. Both water-stress and high VPD strongly...

  10. Vascular plant controls on methane emissions from northern peatforming wetlands

    Microsoft Academic Search

    Anna Joabsson; Torben Røjle Christensen; Bo Wallén

    1999-01-01

    Methane emissions from wetlands are highly variable, both spatially and temporally and at scales ranging from microtopographic to regional differences. To comprehend this variation fully and also to predict responses to climate change, an understanding of the intimate linkage between carbon cycling and methane emission in these systems is needed. The presence of vascular plants has been recognized recently as

  11. Vehicular Diesel control emissions benefit assessment in Mexico City

    NASA Astrophysics Data System (ADS)

    Garcia-Reynoso, J.; Jazcilevich, A. D.; Ruiz-Suarez, L.; Cruz-Nuñez, X.; Rojas, A. R.; Tripp, M. R.

    2013-12-01

    Diesel vehicles contribute in an important proportion to the particle and black carbon (BC) ambient concentrations in urban areas. These pollutants can effect the climate and health. The average age of the Diesel fleet in Mexico is 15 year-old. An introduction of new technologies and retrofit systems can reduce emissions from this type of vehicles. A set of policies were selected and applied in order to identify their economic benefits in health. An air quality model was used to obtain ambient concentrations from the emissions and specific methodology for emissions inventory adjustment was developed for this project. Preliminary results show an important benefit due to the improvement of the emissions reduction from the Diesel fleet. PM2.5 differences for reduction scenario case 1 and base case. Output from WRF-chem using 2005 Naional Emissions Inventory Reductions obtained using data from the initial fleet, fleet temporal variation and substitution policies.

  12. Management controls on nitrous oxide emissions from row crop agriculture

    NASA Astrophysics Data System (ADS)

    Gelfand, I.; Shcherbak, I.; Millar, N.; Robertson, G. P.

    2011-12-01

    Agriculture is a significant source of the potent greenhouse gas (GHG) nitrous oxide (N2O), accounting for ~70% of total anthropic N2O emissions in the US primarily as a result of N fertilizer application. Emissions of N2O are the largest contributor to the global warming potential of row-crop agriculture. Management, including choice of crop type and rotation strongly impacts N2O emissions, but continuous emissions data from row-crops over multiple rotations are lacking. Empirical quantification of these long-term emissions and the development of crop- and rotation-specific N2O emission factors are vital for improving estimates of agricultural GHG emissions, important for informing management practices to reduce agriculture's GHG footprint, and developing mitigation protocols for environmental markets. Over 20 years we measured soil N2O emissions and calculated crop and management specific emission factors in four continuous rotations of corn (Zea mays) - soybean (Glycine max) - wheat (Triticum aestivum) under conventional tillage (CT), zero tillage (NT), low chemical input (LI), and biologically (Org) based management. Two of these systems (LI and Org) included winter cover crops, red clover (Trifolium pratense) or ray (Secale cereale). While average soil N2O fluxes in all systems where similar (2.9±0.2 to 3.8±0.5 g N2O-N ha-1 d-1), there was a significant interaction of total emissions with crop and phase. Surprisingly, the lowest total emissions from the corn period of the rotation were from CT, and the highest from LI, with 608±4 and 983±8 g N2O-N ha-1 crop year-1, respectively. Total emissions during the wheat period of the rotation showed the opposite trend, with total emissions of 942±7 and 524±38 g N2O-N ha-1 crop year-1, for CT ant LI, respectively. Total emissions from the soybean period of the rotation were highest under NT and lowest under CT management (526±5 and 296±2 g N2O-N ha-1 crop year-1, respectively). Emission efficiency, N2O emitted for grain produced, was lowest in CT and highest in Org for corn (0.10 and 0.22 g N2O-N kg-1 grain, respectively). For wheat the emission efficiencies were similar for CT and Org systems, despite N2O emissions from CT being almost double those from Org, reflecting the low grain yields under biological management. For soybean, the emission factors were consistent with total emissions due to similar soybean yields across practices, and were between 0.13 and 0.20 g N2O-N kg-1 grain, for CT and NT, respectively. Based on long-term measurements we show that management choices a) has a major effect on N2O emissions, even under the same rotation, and b) provide different potential mitigation opportunities.

  13. Control of odour emission in wastewater treatment plants by direct and undirected measurement of odour emission capacity.

    PubMed

    Zarra, T; Giuliani, S; Naddeo, V; Belgiorno, V

    2012-01-01

    Odour emissions from wastewater treatment plants (WWTPs) are considered to be the main causes of disturbance noticed by the exposed population and have relevant impacts on both tourism economy and land costs. Odour impact from WWTPs is generated by primary and secondary odour emissions. Primary odour emissions are related especially to the wastewater type and variability discharged into the sewer and directed to the WWTP, and to the wastewater collection and sewage system. Secondary odours are related to the treatment units of the plant. Several studies describe the key role of primary odour emissions and how they are strongly related to odour impacts of WWTPs. In this way, a opportune characterization of the emission capacity of primary odour could be an effective way to control odour emission in the WWTPs. In this study the odour emission capacity (OEC) of different domestic sewers was described and investigated; a correlation between the OEC and the main physical-chemical parameters of wastewater quality was also carried out. Results of this study identify the optimum conditions for sampling and measuring OEC in wastewaters and define its dependence by wastewater quality. These results can contribute to setting the standards for the maximum odourant content of wastewater that are discharged into the publicly owned sewage system. PMID:22907444

  14. Estimates of increased black carbon emissions from electrostatic precipitators during powdered activated carbon injection for mercury emissions control.

    PubMed

    Clack, Herek L

    2012-07-01

    The behavior of mercury sorbents within electrostatic precipitators (ESPs) is not well-understood, despite a decade or more of full-scale testing. Recent laboratory results suggest that powdered activated carbon exhibits somewhat different collection behavior than fly ash in an ESP and particulate filters located at the outlet of ESPs have shown evidence of powdered activated carbon penetration during full-scale tests of sorbent injection for mercury emissions control. The present analysis considers a range of assumed differential ESP collection efficiencies for powdered activated carbon as compared to fly ash. Estimated emission rates of submicrometer powdered activated carbon are compared to estimated emission rates of particulate carbon on submicrometer fly ash, each corresponding to its respective collection efficiency. To the extent that any emitted powdered activated carbon exhibits size and optical characteristics similar to black carbon, such emissions could effectively constitute an increase in black carbon emissions from coal-based stationary power generation. The results reveal that even for the low injection rates associated with chemically impregnated carbons, submicrometer particulate carbon emissions can easily double if the submicrometer fraction of the native fly ash has a low carbon content. Increasing sorbent injection rates, larger collection efficiency differentials as compared to fly ash, and decreasing sorbent particle size all lead to increases in the estimated submicrometer particulate carbon emissions. PMID:22663136

  15. Emissions of Transport Refrigeration Units with CARB Diesel, Gas-to-Liquid Diesel, and Emissions Control Devices

    SciTech Connect

    Barnitt, R. A.; Chernich, D.; Burnitzki, M.; Oshinuga, A.; Miyasato, M.; Lucht, E.; van der Merwe, D.; Schaberg, P.

    2010-05-01

    A novel in situ method was used to measure emissions and fuel consumption of transport refrigeration units (TRUs). The test matrix included two fuels, two exhaust configurations, and two TRU engine operating speeds. Test fuels were California ultra low sulfur diesel and gas-to-liquid (GTL) diesel. Exhaust configurations were a stock muffler and a Thermo King pDPF diesel particulate filter. The TRU engine operating speeds were high and low, controlled by the TRU user interface. Results indicate that GTL diesel fuel reduces all regulated emissions at high and low engine speeds. Application of a Thermo King pDPF reduced regulated emissions, sometimes almost entirely. The application of both GTL diesel and a Thermo King pDPF reduced regulated emissions at high engine speed, but showed an increase in oxides of nitrogen at low engine speed.

  16. Environmental Consequences of Invasive Species: Greenhouse Gas Emissions of Insecticide Use and the Role of Biological Control in Reducing Emissions

    PubMed Central

    Heimpel, George E.; Yang, Yi; Hill, Jason D.; Ragsdale, David W.

    2013-01-01

    Greenhouse gas emissions associated with pesticide applications against invasive species constitute an environmental cost of species invasions that has remained largely unrecognized. Here we calculate greenhouse gas emissions associated with the invasion of an agricultural pest from Asia to North America. The soybean aphid, Aphis glycines, was first discovered in North America in 2000, and has led to a substantial increase in insecticide use in soybeans. We estimate that the manufacture, transport, and application of insecticides against soybean aphid results in approximately 10.6 kg of carbon dioxide (CO2) equivalent greenhouse gasses being emitted per hectare of soybeans treated. Given the acreage sprayed, this has led to annual emissions of between 6 and 40 million kg of CO2 equivalent greenhouse gasses in the United States since the invasion of soybean aphid, depending on pest population size. Emissions would be higher were it not for the development of a threshold aphid density below which farmers are advised not to spray. Without a threshold, farmers tend to spray preemptively and the threshold allows farmers to take advantage of naturally occurring biological control of the soybean aphid, which can be substantial. We find that adoption of the soybean aphid economic threshold can lead to emission reductions of approximately 300 million kg of CO2 equivalent greenhouse gases per year in the United States. Previous studies have documented that biological control agents such as lady beetles are capable of suppressing aphid densities below this threshold in over half of the soybean acreage in the U.S. Given the acreages involved this suggests that biological control results in annual emission reductions of over 200 million kg of CO2 equivalents. These analyses show how interactions between invasive species and organisms that suppress them can interact to affect greenhouse gas emissions. PMID:23977273

  17. Environmental controls over isoprene emission in deciduous oak canopies.

    PubMed

    Harley, P; Guenther, A; Zimmerman, P

    1997-11-01

    In summer 1992, isoprene emission was measured on intact leaves and branches of Quercus alba (L.) at two heights in a forest canopy. Isoprene emission capacity (measured at 30 degrees C and a photosynthetic photon flux density of 1000 micro mol m(-2) s(-1)) was significantly higher in sun leaves than in shade leaves when expressed on a leaf area basis (51 versus 31 nmol m(-2) s(-1); P < 0.01). Because leaf mass per unit area (LMA, g m(-2)) was higher in sun leaves than in shade leaves, emissions of sun and shade leaves expressed on a dry mass basis did not differ significantly (99 versus 89 micro g C g(DW) (-1) h(-1); P = 0.05). Similar measurements in 1995 were consistent with the 1992 data, but data from leaves in more shaded locations demonstrated that isoprene emission capacity decreased with decreasing growth irradiance, irrespective of units of expression. Isoprene emission capacity in leaves of Q. coccinea Muenchh. and Q. velutina Lam. also declined steeply with canopy depth. Emission capacity, on a dry mass basis, showed no obvious pattern with canopy position in Q. prinus L. There was no difference in the temperature response of sun versus shade leaves of Q. alba, but shade leaves exhibited a greater quantum efficiency and saturated at lower irradiance than sun leaves. Rates of isoprene emission measured on branches of Q. alba were approximately 60% of those measured on individual leaves, as a result of self-shading within branch enclosures. It is recommended that within-canopy variation in isoprene emission capacity be incorporated into regional emission models. PMID:14759895

  18. Climatic and Chemical Controls on Methane Emissions from Wetlands

    NASA Technical Reports Server (NTRS)

    Matthews, Elaine; Gauci, Vincent; Prigent, Catherine; Travis, Larry (Technical Monitor)

    2002-01-01

    Natural wetlands are the largest single source of methane to the atmosphere and the only one dominated by climate. Although interannual variations in methane emissions from short-term climate variations are becoming better understood, major uncertainties remain with respect to the sensitivity of wetlands and their CH4 emissions to climate variability, the sensitivity of suppression of wetland methane missions to changes in low-dose sulfate deposition, and the response of wetland dynamics to climate variations. We present results from modeling, field, and remote sensing research that integrate current understanding of the dynamics of wetlands and their methane emissions.

  19. Spontaneous control of HIV-1 viremia in a subject with protective HLA-B plus HLA-C alleles and HLA-C associated single nucleotide polymorphisms.

    PubMed

    Moroni, Marco; Ghezzi, Silvia; Baroli, Paolo; Heltai, Silvia; De Battista, Davide; Pensieroso, Simone; Cavarelli, Mariangela; Dispinseri, Stefania; Vanni, Irene; Pastori, Claudia; Zerbi, Pietro; Tosoni, Antonella; Vicenzi, Elisa; Nebuloni, Manuela; Wong, Kim; Zhao, Hong; McHugh, Sarah; Poli, Guido; Lopalco, Lucia; Scarlatti, Gabriella; Biassoni, Roberto; Mullins, James I; Malnati, Mauro S; Alfano, Massimo

    2014-12-01

    IntroductionUnderstanding the mechanisms by which some individuals are able to naturally control HIV-1 infection is an important goal of AIDS research. We here describe the case of an HIV-1+ woman, CASE1, who has spontaneously controlled her viremia for the last 14 of her 20 years of infection.MethodsCASE1 has been clinically monitored since 1993. Detailed immunological, virological and histological analyses were performed on samples obtained between 2009 and 2011.ResultsAs for other Elite Controllers, CASE1 is characterized by low to undetectable levels of plasma HIV-1 RNA, peripheral blood mononuclear cell (PBMC) associated HIV-1 DNA a reduced in vitro susceptibility of target cells to HIV-1 infection. Furthermore, a slow rate of virus evolution was demonstrated in spite the lack of assumption of any antiretroviral agent. CASE1 failed to transmit HIV-1 to either her sexual male partner or to her child born by vaginal delivery. Normal values and ratios of T and B cells were observed, along with normal histology of the intestinal mucosa. Attempts to isolate HIV-1 from her PBMC and gut-derived cells were unsuccessful, despite expression of normal cell surface levels of CD4, CCRC5 and CXCR4. CASE1 did not produce detectable anti-HIV neutralizing antibodies in her serum or genital mucosal fluid although she displayed potent T cell responses against HIV-1 Gag and Nef. CASE1 also possessed multiple genetic polymorphisms, including HLA alleles (B*14, B*57, C*06 and C*08.02) and HLA-C single nucleotide polymorphisms (SNPs, rs9264942 C/C and rs67384697 del/del), that have been previously individually associated with spontaneous control of plasma viremia, maintenance of high CD4+ T cell counts and delayed disease progressionConclusionsCASE1 has controlled her HIV-1 viremia below the limit of detection in the absence of antiretroviral therapy for more than 14 years and has not shown any sign of immunologic deterioration or disease progression. Co-expression of multiple protective HLA alleles, HLA-C SNPs and strong T cell responses against HIV-1 proteins are the most likely explanation of this very benign case of spontaneous control of HIV-1 disease progression. PMID:25477316

  20. Association of risk factors with spontaneous preterm birth after 28 weeks and neonatal outcome--a case-control study in a tertiary care referral centre.

    PubMed

    Subapriya, Kandasamy; Rao, Arun A

    2009-02-01

    This prospective case-control study was carried out in patients admitted in Government Lady Goschen Hospital, Mangalore to study the risk factors associated with spontaneous preterm birth after 28 weeks and its neonatal outcome when compared with term birth. One hundred women who were admitted in labour of gestational age 28 to 37 weeks were included in study group and similarly 100 women of more than 37 weeks were in the control group. Height, weight and body mass index were significant risk factors associated with preterm birth. When maternal weight increases, the chance of term delivery increased 10%. Previous preterm births and spontaneous abortions increasedthe risk of preterm birth. Birth weight and Apgar score were significantly lower in study group. Neonatal morbidity and mortality were significantly higher in study group. Qualitative variables in frequencies were analysed using Chi-square test. Quantitative variables in mean were analysed using Student's independent 't' test. Multivariate analysis using logistic regression was done to identify the significant factor. It can be concluded that maternal anthropometry and previous obstetric performance are the important factors. These women at risk should be identified and adequate antenatal care to these women might decrease the incidence of preterm birth. Prolongation of gestation and increase in birth weight give favourable neonatal outcome. Good neonatal intensive care unit will not only improve the outcome of preterm birth but also will decrease the socioeconomic burden to the parents, society and the nation. PMID:19585815

  1. Identification, assessment, and control of fugitive particulate emissions. Final report, April 1983-April 1986

    SciTech Connect

    Cowherd, C.; Kinsey, J.S.

    1986-08-01

    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 particulate emissions. The manual's organizational structure follows the steps to be taken in developing a cost-effective control strategy for fugitive particulate emissions. The procedural steps are the same whether the sources of interest are within a specific industrial facility or distributed over an air-quality control jurisdiction. the manual summarizes the quality and extent of published performance data for control systems applicable to open dust sources and process sources. In addition to presenting a cost-analysis methodology, the manual identifies primary cost elements and sources of cost data and presents a fully worked industrial example of cost-effective control strategy development.

  2. 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...

  3. 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...

  4. 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.

  5. Gaseous and particulate emission profiles during controlled rice straw burning

    NASA Astrophysics Data System (ADS)

    Sanchis, E.; Ferrer, M.; Calvet, S.; Coscollà, C.; Yusà, V.; Cambra-López, M.

    2014-12-01

    Burning of rice straw can emit considerable amounts of atmospheric pollutants. We evaluated the effect of rice straw moisture content (5%, 10%, and 20%) on the emission of carbon dioxide (CO2) and on the organic and inorganic constituents of released particulate matter (PM): dioxins, heavy metals, and polycyclic aromatic hydrocarbons (PAHs). Four burning tests were conducted per moisture treatment using the open chamber method. Additionally, combustion characteristics, including burning stages, durations, temperature, and relative humidity, were recorded. Burning tests showed flaming and smoldering stages were significantly longer in 20% moisture treatment (P < 0.05) compared with the rest. The amount of burned straw and ashes decreased with increasing straw moisture content (P < 0.001). Carbon dioxide was the main product obtained during combustion with emission values ranging from 692 g CO2 kg dry straw-1 (10% moisture content) to 835 g CO2 kg dry straw-1 (20% moisture content). Emission factors for PM were the highest in 20% moisture treatment (P < 0.005). Fine PM (PM2.5) accounted for more than 60% of total PM mass. Emission factors for dioxins increased with straw moisture content, being the highest in 20% moisture treatment, although showing a wide variability among burning tests (P > 0.05). Emissions factors for heavy metals were low and similar among moisture treatments (P > 0.05). Emission factors for individual PAHs were generally higher in 20% moisture treatment. Overall, emission factors of atmospheric pollutants measured in our study were higher in the 20% moisture content. This difference could be attributed to the incomplete combustion at higher levels of rice straw moisture content. According to our results, rice straw burning should be done after straw drying and under minimal moisture conditions to lower pollutant emission levels.

  6. Factors controlling emissions of dimethylsulphide from salt marshes

    NASA Technical Reports Server (NTRS)

    Dacey, John W. H.; Wakeham, Stuart G.; King, Gary M.

    1987-01-01

    Salt marshes are presently identified as systems exhibiting high area-specific sulfur emission in the form of dimethylsulfide (DMS) and H2S, with the former predominating in vegetated areas of the marshes. Attention is presently given to the distribution of DMS in salt marshes; it is found that this compound primarily arises from physiological processes in the leaves of higher plants, especially the grass species Spartina alterniflora. Uncertainties associated with DMS emission measurements are considered.

  7. Emission characteristics and control efficiency of acidic and basic gases and aerosols from packed towers

    NASA Astrophysics Data System (ADS)

    Tsai, Chuen-Jinn; Chang, Chang-Tso; Liu, Tsing-Wei; Huang, Chun-Chao; Chien, Chih-Liang; Chein, Hung Min

    Large amount of acidic liquids, such as H 2SO 4, HF, HCl and HNO 3, and basic NH 3 liquid are used in high-tech industries in cleaning and etching processes in the Hsinchu Science-Based Industrial Park in Taiwan. The industries use packed towers (or scrubbers) to control emission of these inorganic pollutants, in which acidic gases but not particles are regulated by the Taiwan EPA's strict emission standard for semiconductor industry. To understand whether the emission standard is met and to investigate the emission rates, emission profiles, emission factors, and control efficiencies of various gaseous/aerosol species, measurement of pollutants before and after the packed towers was conducted using a sensitive porous metal sampler during January 2001 to February 2003. Results show that the pollutants are mainly in the gaseous phase, and the control efficiency of pollutants is low and variable when the inlet concentration is low. In addition to the control efficiency data, emission factors before the control device for various gas and particle species have also been developed for estimating the emission rates.

  8. Influence of binder viscosity on the control of infrared emissivity in low emissivity coating

    NASA Astrophysics Data System (ADS)

    Yuan, Le; Weng, Xiaolong; Deng, Longjiang

    2013-01-01

    Low emissivity is the complex system and polymer binder is one of the most important factors that affect optical and mechanical properties of the coating. Low infrared emissivity coatings were prepared by using flake aluminum particles and three types of polymer resins as fillers and binders, respectively. The influence of polymer binder viscosity on pigment particles distribution, surface morphology and infrared emissivity of the coating was systematically investigated. The results indicate that infrared emissivity of the coating can be strongly affected by the resin viscosity at the same preparation condition, which induces different aluminum particles distribution and surface morphology of the coating. Low resin viscosity is helpful for aggregating pigments and reducing the top polymer layer thickness near the surface, thus the infrared emissivity is reduced. If the resin viscosity value is decreased by two orders of magnitude, the infrared emissivity values would be reduced as much as 0.2. Additionally, a theoretical model is proposed to account for this mechanism, which indicates that sedimentation, evaporation and diffusion play important roles in forming different aluminum particles distribution during the drying process of the coating.

  9. Preventive control of odor emissions through manipulation of operational parameters during the active phase of composting.

    PubMed

    Zhang, Wenxiu; Lau, Anthony K; Wen, Zhiping S

    2009-06-01

    Better understanding of the effects of key operational parameters or environmental factors on odor emission is of critical importance for minimizing the generation of composting odors. A series of laboratory experiments was conducted to examine the effects of various operating conditions on odor emissions. The results revealed that airflow rates that were too high or too low could result in higher total odor emissions. An optimal flowrate for odor control would be approximately 0.6 L/min.kg dry matter with intermittent aeration and a duty cycle of 33%. Temperature setpoint at 60 degrees C appeared to be a turning point for odor emission. Below this point, odor emissions increased with increasing temperature setpoint; conversely, odor emissions decreased with increasing temperature setpoint above this point. With regard to the composting material properties, odor emissions were greatly affected by the initial moisture content of feedstock. Both peak odor concentration and emission rate generally increased with higher initial moisture content. Odor emission was significant only at moisture levels higher than 65%. An initial moisture level below 45% is not recommended due to concern with the resulting lower degree of biodegradation. Biodegradable volatile solids content (BVS) of feedstock had pronounced effect on odor emissions. Peak odor concentration and emission rate increased dramatically as BVS increased from 45% to 65%, thus, total odor emission increased exponentially with BVS. PMID:20183055

  10. Parameters controlling nitric oxide emissions from gas turbine combustors

    NASA Technical Reports Server (NTRS)

    Heywood, J. B.; Mikus, T.

    1973-01-01

    Nitric oxide forms in the primary zone of gas turbine combustors where the burnt gas composition is close to stoichiometric and gas temperatures are highest. It was found that combustor air inlet conditions, mean primary zone fuel-air ratio, residence time, and the uniformity of the primary zone are the most important variables affecting nitric oxide emissions. Relatively simple models of the flow in a gas turbine combustor, coupled with a rate equation for nitric oxide formation via the Zeldovich mechanism are shown to correlate the variation in measured NOx emissions. Data from a number of different combustor concepts are analyzed and shown to be in reasonable agreement with predictions. The NOx formation model is used to assess the extent to which an advanced combustor concept, the NASA swirl can, has produced a lean well-mixed primary zone generally believed to be the best low NOx emissions burner type.

  11. Parameters controlling nitric oxide emissions from gas turbine combustors.

    NASA Technical Reports Server (NTRS)

    Heywood, J. B.; Mikus, T.

    1973-01-01

    Nitric oxide forms in the primary zone of gas turbine combustors where the burst gas composition is close to stoichiometric and gas temperatures are highest. It has been found that combustor air inlet conditions, mean primary zone fuel-air ratio, residence time, and the uniformity of the primary zone are the most important variables affecting nitric oxide emissions. Relatively simple models of the flow in a gas turbine combustor, coupled with a rate equation for nitric oxide formation via the Zeldovich mechanism are shown to correlate the variation in measured NO sub x emissions. Data from a number of different combustor concepts are analyzed and shown to be in reasonable agreement with predictions. The NO sub x formation model is used to assess the extent to which an advanced combustor concept, the NASA swirl can, has produced a lean well-mixed primary zone generally believed to be the best low NO sub x emissions burner type.

  12. Systematic Field Study of NO(x) Emission Control Methods for Utility Boilers.

    ERIC Educational Resources Information Center

    Bartok, William; And Others

    A utility boiler field test program was conducted. The objectives were to determine new or improved NO (x) emission factors by fossil fuel type and boiler design, and to assess the scope of applicability of combustion modification techniques for controlling NO (x) emissions from such installations. A statistically designed test program was…

  13. 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...

  14. Controls of Dust Emissions by Vegetation and Geomorphic Setting: an Evaluation Using Dust Storm Frequency Data

    Microsoft Academic Search

    S. Engelstaedter; K. E. Kohfeld; I. Tegen; S. P. Harrison

    2002-01-01

    The latest generation of global dust cycle models largely estimate dust emission rates using surface wind speed and soil moisture dependencies, and require tuning to reproduce observed dust concentrations and deposition rates. In light of regional studies that suggest both geomorphic setting and the nature of the vegetation cover are important controls on dust emission, more recent dust cycle simulations

  15. 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...

  16. 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...

  17. 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...

  18. DEVELOPMENT OF TECHNOLOGY FOR CONTROLLING BOP (BASIC OXYGEN PROCESS) CHARGING EMISSIONS

    EPA Science Inventory

    The report gives results of a study of the basic oxygen process (BOP) hot metal charging emission control technology, conducted with a 900 kg pilot vessel designed for the experiments. Complete instrumentation was provided to measure the emissions, the effectiveness of the variou...

  19. PRELIMINARY PERFORMANCE AND COST ESTIMATES OF MERCURY EMISSION CONTROL OPTIONS FOR ELECTRIC UTILITY BOILERS

    EPA Science Inventory

    The paper discusses preliminary performance and cost estimates of mercury emission control options for electric utility boilers. Under the Clean Air Act Amendments of 1990, EPA had to determine whether mercury emissions from coal-fired power plants should be regulated. To a...

  20. Single-Walled Carbon Nanotubes of Controlled Diameter and Bundle Size and Their Field Emission Properties

    E-print Network

    Resasco, Daniel

    Single-Walled Carbon Nanotubes of Controlled Diameter and Bundle Size and Their Field Emission: June 8, 2005 Field emission studies were conducted on as-produced CoMoCAT single-walled carbon nanotube electron emitter. By adjusting the catalytic synthesis conditions, single-walled carbon nanotubes (SWNT

  1. Factors controlling the occurrence of the Jovian decametric radio emission

    NASA Astrophysics Data System (ADS)

    Zaitsev, V. V.; Shaposhnikov, V. E.; Rucker, H. O.

    The statistical analysis of occurrence of Io-related Jovian decametric radio (DAM) emission shows that the occurrence of the emission increase when Io is in the longitude range 120° -300° (Io's longitude in the frame III). Another result of the statistical analysis is a predominance of DAM emission sources in the northern hemisphere of Jupiter. We show that these phenomena are the result of the joint effect of two factors - the variation of the efficiency of particle acceleration in the ionosphere of the satellite Io and the variation of the broadening of the angular spectrum of accelerated particles during their pass through Io's plasma torus depending on Io's longitude. The planes of the rotational, magnetic and centrifugal (for Io's torus) equators do not coincide. As a result the magnetic field near the satellite Io, which determines the accelerated particle efficiency [1], changes periodically. The most effective acceleration takes place in the longitude range 120° ? ?Io ? 300° . Just in this longitude range the satellite Io appears to be "screened" by the plasma torus of the southern hemisphere. Making their way to the southern hemisphere, the particles are scattered in the torus plasma 2° , within which they and withdrawn from a narrow range of pitch-angles ??0 can reach the southern hemisphere [2]. Therefore in the mentioned longitude range northern sources of DAM emission should be concentrated. At the same time in the longitude range, where the "screening" effect of the plasma torus in the southern direction is negligible, the efficiency of the accelerated mechanism is essentially smaller due to the decrease of the magnetic field near Io. Therefore the southern sources turn to be weaker and are located mainly outside the longitude range, where the emission from the northern sources predominates. Since the emission from the northern sources predominates, the active longitudes are determined basically by this emission and are in the range 120° ? ?Io ? 300° . The distribution of accelerated electron fluxes near the southern foot of the magnetic tube of Io coincides well with the distribution of the occurrence of the left-hand polarized emission from the source Io-C. References 1. Zaitsev V. V., Shaposhnikov V. E., Rucker H. O. 2003, Astronomy Report, 80, 761. 2. Zaitsev V. V., Shaposhnikov V. E., Rucker H. O. 2006, Astronomy and Astrophysics, in press.

  2. 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...

  3. 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

  4. 40 CFR 270.315 - What air emissions control information must I keep at my facility?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...your facility: (a) Documentation for each floating roof cover installed on a tank subject to 40 CFR 264.1084(d)(1) or...enclosure used to control air pollutant emissions from tanks or containers under requirements of 40 CFR...

  5. 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...

  6. Digital controlled luminescent emission via patterned deposition of lanthanide coordination compounds.

    PubMed

    Zhang, Hua-Bin; Liu, Meng; Lei, Xiaoping; Wen, Tian; Zhang, Jian

    2014-08-13

    Presented here is a new direct patterning method, printer-type lithography technology, for the formation of lanthanide coordination compounds (LCCs) single crystal in different spatial locations. We first integrate this technology in digital controlled emission by patterned deposition of LCCs. We demonstrate its usefulness in the control of emission intensity by regulating print cycles, so that the emission intensity can be digitally controlled. This printer technology can also be used to precisely control the location at which a single LCC crystal is grown, which provides great promise in the application of anticounterfeiting barcode. Besides, by varying the stoichiometric ratio of the lanthanide ions in the identical cartridge, a fluent change of emission colors from white, orange, pink, to blue green was achieved. Therefore, this low-cost and high-throughput patterning technique can be readily applied to a wide range of areas including micro-/nanofabrication, optics, and electronics studies. PMID:25003217

  7. 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...

  8. COST OF CONTROLLING DIRECTLY EMITTED ACIDIC EMISSIONS FROM MAJOR INDUSTRIAL SOURCES

    EPA Science Inventory

    The report gives results of estimates, using a model plant approach, of costs for retrofitting selected acidic emission control systems to utility and industrial boilers, Claus sulfur recovery plants, catalytic cracking units, primary copper smelters, coke oven plants, primary al...

  9. 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...

  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. Test results for uncontrolled (com...

  11. 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...

  12. 40 CFR 86.1717-99 - Emission control diagnostic system for 1999 and later light-duty vehicles and light-duty trucks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Emission control diagnostic system for 1999 and later light-duty...AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND...86.1717-99 Emission control diagnostic system for 1999 and later...

  13. 40 CFR 86.1717-01 - Emission control diagnostic system for 1999 and later light-duty vehicles and light-duty trucks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Emission control diagnostic system for 1999 and later light-duty...AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND...86.1717-01 Emission control diagnostic system for 1999 and later...

  14. Candidate gene analysis of spontaneous preterm delivery: New insights from re-analysis of a case-control study using case-parent triads and control-mother dyads

    PubMed Central

    2011-01-01

    Background Spontaneous preterm delivery (PTD) has a multifactorial etiology with evidence of a genetic contribution to its pathogenesis. A number of candidate gene case-control studies have been performed on spontaneous PTD, but the results have been inconsistent, and do not fully assess the role of how two genotypes can impact outcome. To elucidate this latter point we re-analyzed data from a previously published case-control candidate gene study, using a case-parent triad design and a hybrid design combining case-parent triads and control-mother dyads. These methods offer a robust approach to genetic association studies for PTD compared to traditional case-control designs. Methods The study participants were obtained from the Norwegian Mother and Child Cohort Study (MoBa). A total of 196 case triads and 211 control dyads were selected for the analysis. A case-parent triad design as well as a hybrid design was used to analyze 1,326 SNPs from 159 candidate genes. We compared our results to those from a previous case-control study on the same samples. Haplotypes were analyzed using a sliding window of three SNPs and a pathway analysis was performed to gain biological insight into the pathophysiology of preterm delivery. Results The most consistent significant fetal gene across all analyses was COL5A2. The functionally similar COL5A1 was significant when combining fetal and maternal genotypes. PON1 was significant with analytical approaches for single locus association of fetal genes alone, but was possibly confounded by maternal effects. Focal adhesion (hsa04510), Cell Communication (hsa01430) and ECM receptor interaction (hsa04512) were the most constant significant pathways. Conclusion This study suggests a fetal association of COL5A2 and a combined fetal-maternal association of COL5A1 with spontaneous PTD. In addition, the pathway analysis implied interactions of genes affecting cell communication and extracellular matrix. PMID:22208904

  15. Federal Control of Carbon Dioxide Emissions: What are the Options?

    Microsoft Academic Search

    Reitze Jr. Arnold W

    2009-01-01

    The U.S. Supreme Court in Massachusetts v. EPA held that carbon dioxide is a pollutant under the Clean Air Act (CAA) and remanded the case to EPA. The Agency must decide whether CO2 emissions contribute to climate change. If the Agency responds affirmatively, it must meet other requirements of the CAA in order to regulate carbon dioxide or other greenhouse

  16. Emissions from a controlled fire in municipal solid waste bales

    Microsoft Academic Search

    Diauddin R. Nammari; William Hogland; Marcia Marques; Sven Nimmermark; Viatcheslav Moutavtchi

    2004-01-01

    Environmental and safety aspects of seasonal storage of baled municipal solid waste to be used as fuel for energy production (waste fuel), was investigated and experiments were carried out on burning of bales. The flammability, combustion processes and emissions were studied by simulating, in small-scale, potential effects of a possible fire in full-scale bale storage area. Despite the high water

  17. 69 FR 2398 - Control of Emissions From Highway Motorcycles

    Federal Register 2010, 2011, 2012, 2013, 2014

    2004-01-15

    ...fact, we estimate that the fuel costs savings associated with...Test Procedures? D. What Test Fuel Is Required for Emission Testing...classes, which are based on the size of the engine and are used to distinguish...about $27 million (including fuel savings) annually by the...

  18. Diesel fuel burner for diesel emissions control system

    SciTech Connect

    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. CONTROL TECHNOLOGIES FOR PARTICULATE AND TAR EMISSIONS FROM COAL CONVERTERS

    EPA Science Inventory

    The report gives results of a characterization of solid and tar particulate emissions in raw product gases from several types of coal gasifiers, in terms of their total quantities, chemical composition, and size distribution. Fixed-bed gasifiers produce the smallest particulate l...

  20. PM - EMISSION CHARACTERIZATION, FACTORS AND CONTROLS (NAS 12)

    EPA Science Inventory

    The program will focus on diesel trucks, prescribed and open burning, construction sites and residential wood combustion. Differences in emission rates due to changes in operating conditions and fuel type will be included in the revised factors. Ammonia research will produce i...

  1. 40 CFR 89.110 - Emission control information label.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...3) EPA standardized engine family designation; (4) Engine...Administrator upon request; (9) Family emission limits (FELs) if...Engines belonging to an engine family that has been certified as a...1) to be designated as Blue Sky Series engines must...

  2. 40 CFR 89.110 - Emission control information label.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...3) EPA standardized engine family designation; (4) Engine...Administrator upon request; (9) Family emission limits (FELs) if...Engines belonging to an engine family that has been certified as a...1) to be designated as Blue Sky Series engines must...

  3. 40 CFR 89.110 - Emission control information label.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...3) EPA standardized engine family designation; (4) Engine...Administrator upon request; (9) Family emission limits (FELs) if...Engines belonging to an engine family that has been certified as a...1) to be designated as Blue Sky Series engines must...

  4. Method and apparatus for controlling gasoline vapor emissions

    Microsoft Academic Search

    Hirt

    1987-01-01

    This patent describes an apparatus for abatement of gasoline vapor emissions from a vent pipe at a gasoline service station or the like in which a vapor piping system interconnects the vent pipe with gasoline storage tanks and gasoline dispensing nozzles in the service station. The apparatus includes a pilot burner with pilot ignition means and a main burner with

  5. Combustion control of PCDD\\/PCDF emissions from municipal waste-incinerators in North America

    Microsoft Academic Search

    Kilgroe

    1990-01-01

    The paper discusses combustion control of emissions of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) from municipal waste incinerators in North America. New regulations to control air pollution emissions from municipal waste incineration have been enacted in Canada and are being developed in the U.S. Regulations in both countries will require the use of good combustion practice (GCP). The U.S.

  6. 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.

  7. The (perceived) meaning of spontaneous thoughts.

    PubMed

    Morewedge, Carey K; Giblin, Colleen E; Norton, Michael I

    2014-08-01

    Spontaneous thoughts, the output of a broad category of uncontrolled and inaccessible higher order mental processes, arise frequently in everyday life. The seeming randomness by which spontaneous thoughts arise might give people good reason to dismiss them as meaningless. We suggest that it is precisely the lack of control over and access to the processes by which they arise that leads people to perceive spontaneous thoughts as revealing meaningful self-insight. Consequently, spontaneous thoughts potently influence judgment. A series of experiments provides evidence supporting two hypotheses. First, we hypothesize that the more a thought is perceived to be spontaneous, the more it is perceived to provide meaningful self-insight. Participants perceived more spontaneous kinds of thought (e.g., intuition) to reveal greater self-insight than did more controlled kinds of thought in Study 1 (e.g., deliberation). In Studies 2 and 3, participants perceived thoughts with the same content and target to reveal greater self-insight when spontaneously rather than deliberately generated (i.e., childhood memories and impressions formed). Second, we hypothesize that the greater self-insight attributed to thoughts that are (perceived to be) spontaneous leads those thoughts to more potently influence judgment. Participants felt more sexually attracted to an attractive person whom they thought of spontaneously than deliberately in Study 4, and reported their commitment to a current romantic relationship would be more affected by the spontaneous rather than deliberate recollection of a good or bad experience with their romantic partner in Study 5. PMID:24820251

  8. High-dimensional immunomonitoring models of HIV-1–specific CD8 T-cell responses accurately identify subjects achieving spontaneous viral control

    PubMed Central

    Ndhlovu, Zaza M.; Chibnik, Lori B.; Proudfoot, Jacqueline; Vine, Seanna; McMullen, Ashley; Cesa, Kevin; Porichis, Filippos; Jones, R. Brad; Alvino, Donna Marie; Hart, Meghan G.; Stampouloglou, Eleni; Piechocka-Trocha, Alicja; Kadie, Carl; Pereyra, Florencia; Heckerman, David; De Jager, Philip L.; Walker, Bruce D.

    2013-01-01

    The development of immunomonitoring models to determine HIV-1 vaccine efficacy is a major challenge. Studies suggest that HIV-1–specific CD8 T cells play a critical role in subjects achieving spontaneous viral control (HIV-1 controllers) and that they will be important in immune interventions. However, no single CD8 T-cell function is uniquely associated with controller status and the heterogeneity of responses targeting different epitopes further complicates the discovery of determinants of protective immunity. In the present study, we describe immunomonitoring models integrating multiple functions of epitope-specific CD8 T cells that distinguish controllers from subjects with treated or untreated progressive infection. Models integrating higher numbers of variables and trained with the least absolute shrinkage and selection operator (LASSO) variant of logistic regression and 10-fold cross-validation produce “diagnostic tests” that display an excellent capacity to delineate subject categories. The test accuracy reaches 75% area under the receiving operating characteristic curve in cohorts matched for prevalence of protective alleles. Linear mixed-effects model analyses show that the proliferative capacity, cytokine production, and kinetics of cytokine secretion are associated with HIV-1 control. Although proliferative capacity is the strongest single discriminant, integrated modeling of different dimensions of data leverages individual associations. This strategy may have important applications in predictive model development and immune monitoring of HIV-1 vaccine trials. PMID:23233659

  9. 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

  10. Emission Controls Versus Meteorological Conditions in Determining Aerosol Concentrations in Beijing during the 2008 Olympic Games

    SciTech Connect

    Gao, Yi; Liu, Xiaohong; Zhao, Chun; Zhang, Meigen

    2011-12-12

    A series of emission control measures were undertaken in Beijing and the adjacent provinces in China during the 2008 Beijing Olympic Games on August 8th-24th, 2008. This provides a unique opportunity for investigating the effectiveness of emission controls on air pollution in Beijing. We conducted a series of numerical experiments over East Asia for the period of July to September 2008 using a coupled meteorology-chemistry model (WRF-Chem). Model can generally reproduce the observed variation of aerosol concentrations. Consistent with observations, modeled concentrations of aerosol species (sulfate, nitrate, ammonium, black carbon, organic carbon, total particulate matter) in Beijing were decreased by 30-50% during the Olympic period compared to the other periods in July and August in 2008 and the same period in 2007. Model results indicate that emission controls were effective in reducing the aerosol concentrations by comparing simulations with and without emission controls. However, our analysis suggests that meteorological conditions (e.g., wind direction and precipitation) are at least as important as emission controls in producing the low aerosol concentrations appearing during the Olympic period. Transport from the regions surrounding Beijing determines the temporal variation of aerosol concentrations in Beijing. Based on the budget analysis, we suggest that emission control strategy should focus on the regional scale instead of the local scale to improve the air quality over Beijing.

  11. Anisotropic photo-control of spontaneous polarization in BiFeO3 thin films: Indications of photo-assisted magnetoelectric effect

    NASA Astrophysics Data System (ADS)

    Rana, D. S.; Kawayama, I.; Murakami, H.; Tonouchi, M.

    2008-03-01

    The terahertz (THz) emission from multiferroic BiFeO3 (BFO) due to ultra-fast depolarization of electric order helps in evaluating its ferroelectric behavior [1]. In this work, we investigate THz-emission in BFO films on (LaAlO3)0.3(Sr2AlTaO6)0.7 (LSAT) substrates along (100), (110) and (111) directions. THz emission amplitude (ETHz) and its electric field dependence are similar in BFO (100) and BFO (110); ETHz as function of electric field translates to ferroelectric-like hysteresis loop, and sign and amplitude of THz-emission are commensurate with the applied electric field. On the contrary, in BFO (111) the hysteretic loop is absent, ETHz varies linearly with electric field and the polarity of THz-emission is opposite to that of the electric field. These results suggest that THz-emission is mainly a result of ultrafast depolarization but with a superimposed character of ultrafast reorientation or demagnetization of antiferromagnetic (AFM) order. Though AFM order in BFO makes the determination of magnetoelectric (ME) coupling rather difficult, the photo-assisted electric field control of AFM order shown in the present work is suggestive of photo-assisted ME effect. 1. K. Takahashi et al., Phys. Rev. Lett. 96, 117402 (2006).

  12. Physical and chemical characterisation of PM emissions from two ships operating in European Emission Control Areas

    NASA Astrophysics Data System (ADS)

    Moldanová, J.; Fridell, E.; Winnes, H.; Holmin-Fridell, S.; Boman, J.; Jedynska, A.; Tishkova, V.; Demirdjian, B.; Joulie, S.; Bladt, H.; Ivleva, N. P.; Niessner, R.

    2013-12-01

    In this paper emission factors (EFs) for particulate matter (PM) and some sub-components as well as gaseous substances were investigated in two onboard measurement campaigns. Emissions from two 4-stroke main engines were measured under stable-load conditions. The impact of varying engine load on the emissions was investigated on one of the engines, and the impact of fuel quality on the other, where heavy fuel oil (HFO) with sulphur content 1% and 0.5% and marine gas oil (MGO) with sulphur content 0.1% were used. Furthermore, emissions from one auxiliary engine were studied. The measured EFs for PM mass were in the range of 0.3 to 2.7 g kg-1 fuel with the lowest values for emissions from the combustion of MGO, and the highest values for HFO with a sulphur content of 1%. The PM mass size distribution was dominated by particles in accumulation mode. Emission factors for particle numbers EF(PN) in the range of 5 × 1015-1 × 1017 # kg-1 fuel were found, the number concentration was dominated by particles in the ultrafine mode and ca. 2/3 of the particle number were non-volatile. The most abundant component of the PM mass was organic carbon, making up 25-60% of the PM. The measured EFs for organic carbon (OC) were 0.6 g kg-1 fuel for HFO and 0.2 g kg-1 fuel for MGO. Elemental carbon (EC) made up 10-38% of the PM mass, with no significant differences between HFO and MGO fuels. The concentrations of metals on sampled filters were investigated with energy dispersive X-ray fluorescence (EDXRF) and the detected metal elements in exhaust when using HFO was concluded to originate from both the fuel (V, Ni, Fe) and the lubricant (Ca, Zn), while for the case of MGO combustion, most of the metals were concluded to originate from the lubricants. The measured emission factors for sulphate particles, EF (SO2-4), were low, ca. 0.1-0.2 g kg-1 fuel for HFO with 1% sulphur, 0.07-0.09 g kg-1 fuel for HFO with 0.5% sulphur and 0.003-0.006 g kg-1 fuel for MGO. This corresponds to 0.1-0.8% and 0.1-0.6% of fuel S converted to PM sulphate for HFO and MGO, respectively. Scanning transmission electron microscopy (STEM) images of the collected PM showed three different types of particles: relatively pure soot; char and char-mineral particles; and amorphous, probably organic particles containing inorganic impurities. The maps of elements obtained from STEM showed a heterogeneous composition of primary soot particles with respect to the trace metals and sulphur. Temperature-programmed oxidation (TPO) of PM showed higher soot oxidation reactivity compared to automotive diesel soot, PM from the HFO exhaust being more reactive than PM from the MGO exhaust. Oxidative potential measured as the rate of consumption of Dithiothreitol (DTT) was for the first time measured on PM from ship exhaust. The obtained values were between 0.01 and 0.04 nmol DTT min-1 ?g-1 PM, which is quite similar to oxidative potentials of PM collected at urban and traffic sites. The data obtained during the experiments add information about emission factors for both gaseous and PM-bound compounds from ship engines using different fuels and under different engine-load conditions. Observed variability of the EFs illustrates uncertainties of these emission factors as a result of influences from fuel and lubricant composition, from differences between individual engines and from the differences in sampling conditions.

  13. Spectral control of thermal emission by periodic microstructured surfaces in the near-infrared region.

    PubMed

    Sai, H; Yugami, H; Akiyama, Y; Kanamori, Y; Hane, K

    2001-07-01

    Thermal emissive properties of microstructured surfaces are measured in the near-infrared region. Two-dimensional periodic microstructured surfaces with metal coatings are fabricated with Si anisotropic etching and laser ablation techniques. The structural periods of the samples are 2.0 and 1.5 microm. Clear selective-emission bands are observed experimentally. This selective emission is attributed to the resonance effect between the emissive field and the surface microstructures. In addition, numerical calculation computed with rigorous coupled-wave analysis (RCWA) is performed on the microstructured samples. The selective-emission peaks measured through experiments can be reproduced well by RCWA, and this result suggests strongly that the thermal radiation from periodic structures may have spatial coherence. It is confirmed that the surface microstructure can be applied to the control of spectral emission from high-temperature materials. PMID:11444538

  14. Quadratic rollback: A technique to model ambient concentrations due to undefined emission controls

    SciTech Connect

    Duff, M.; Horst, R.L. Jr. [Mathtech, Inc. (United States); Johnson, T.R. [TRJ Environmental, Inc. (United States)

    1998-12-31

    Rollback methods are often employed to assess the impact of emission controls when actual emission controls are not defined or can not be modeled. Two rollback methods are commonly used, proportional rollback and peak shaving. Proportional rollback assumes that if manmade emissions from all sources in an area are reduced by one percent, then anthropogenic pollutant concentrations are also reduced by one percent. Proportional rollback assumes modeled concentrations are first-order linear functions in terms of the level of emission controls that limit peak emissions. Peak shaving assumes that no change in concentrations occurs except for the specific hours that an ambient standard is exceeded, and then the concentrations are instantly adjusted such that the ambient standard is just met. Analyses of air quality standards often use proportional rollback to assess the impact of control strategies crafted to meet these standards. By design, proportional rollback attains ambient standards yet often underpredicts concentrations outside of peak concentration periods. Peak shaving is also unrealistic because neither emission sources nor atmospheric responses to emissions can instantly adjust pollution concentrations so as to avoid violation of a concentration-based standard. Assuming compliance with a standard, these two techniques generally bound the expected level of off-peak concentrations. This paper presents a new methodology that simulates concentrations resulting from emission controls required to meet a concentration-based standard. The model is based on the assumption that post-control concentration over time is a smooth mathematical function of uncontrolled concentrations and the level of control required for compliance. The model uses historical monitored data and produces simulations that do not appear as overcontrolled as proportional rollback methods and yet not as undercontrolled as peak shaving methods.

  15. 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.

  16. Intussusception risk after RotaTeq vaccination: evaluation from worldwide spontaneous reporting data using a self-controlled case series approach.

    PubMed

    Escolano, Sylvie; Hill, Catherine; Tubert-Bitter, Pascale

    2015-02-18

    The increased risk of intussusception after vaccination with the rhesus-human reassortant rotavirus vaccine Rotashield led to its withdrawal in 2005. We assess the risk of intussusception following the pentavalent rotavirus vaccine (RV5) on the basis of worldwide reports to the manufacturer up to May 2014, using a self-controlled case series. The method had to be modified to account for the under-reporting, a specific feature of pharmacovigilance spontaneous reports. The risk of intussusception occurring in either of the 0- to 2-day, 3- to 7-day or 8- to 14-day risk periods, was compared to the risk in the 15- to 30-day period. A total of 502 cases occurring 0-30 days after a vaccine dose were studied, including 188 cases after the first dose, 190 cases after the second dose, and 124 cases after the third dose. The incidence risk ratio relative to the control period was highest for the 3- to 7-day period and equal to 3.45 (95% CI 1.84-6.55), 1.63 (0.86-3.13) and 1.73 (0.86-3.51) after the first, second and third dose, respectively. Rotavirus vaccination with RV5 increases the risk of intussusception 3-7 days following vaccination, mainly after the first dose and marginally after the second and third doses. The risk is small and restricted to a short time window. It does not outweigh the benefit of the vaccination, but parents of vaccinated infants should be informed in order to react appropriately to the first symptoms. With appropriate assumptions about the reporting rate, spontaneous reports of adverse events after vaccination can be studied to evaluate vaccine safety. PMID:25596460

  17. Single photon emission from site-controlled InGaN/GaN quantum dots

    SciTech Connect

    Zhang, Lei; Hill, Tyler A.; Deng, Hui, E-mail: dengh@umich.edu [Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, Michigan 48109 (United States)] [Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, Michigan 48109 (United States); Teng, Chu-Hsiang; Lee, Leung-Kway; Ku, Pei-Cheng, E-mail: peicheng@umich.edu [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109 (United States)] [Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109 (United States)

    2013-11-04

    Single photon emission was observed from site-controlled InGaN/GaN quantum dots. The single-photon nature of the emission was verified by the second-order correlation function up to 90?K, the highest temperature to date for site-controlled quantum dots. Micro-photoluminescence study on individual quantum dots showed linearly polarized single exciton emission with a lifetime of a few nanoseconds. The dimensions of these quantum dots were well controlled to the precision of state-of-the-art fabrication technologies, as reflected in the uniformity of their optical properties. The yield of optically active quantum dots was greater than 90%, among which 13%–25% exhibited single photon emission at 10?K.

  18. Single photon emission from site-controlled InGaN/GaN quantum dots

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Teng, Chu-Hsiang; Hill, Tyler A.; Lee, Leung-Kway; Ku, Pei-Cheng; Deng, Hui

    2013-11-01

    Single photon emission was observed from site-controlled InGaN/GaN quantum dots. The single-photon nature of the emission was verified by the second-order correlation function up to 90 K, the highest temperature to date for site-controlled quantum dots. Micro-photoluminescence study on individual quantum dots showed linearly polarized single exciton emission with a lifetime of a few nanoseconds. The dimensions of these quantum dots were well controlled to the precision of state-of-the-art fabrication technologies, as reflected in the uniformity of their optical properties. The yield of optically active quantum dots was greater than 90%, among which 13%-25% exhibited single photon emission at 10 K.

  19. Single Photon Emission from Site-Controlled InGaN/GaN Quantum Dots

    E-print Network

    Lei Zhang; Chu-Hsiang Teng; Tyler A. Hill; Leung-Kway Lee; Pei-Cheng Ku; Hui Deng

    2013-11-08

    Single photon emission was observed from site-controlled InGaN/GaN quantum dots. The single-photon nature of the emission was verified by the second-order correlation function up to 90 K, the highest temperature to date for site-controlled quantum dots. Micro-photoluminescence study on individual quantum dots showed linearly polarized single exciton emission with a lifetime of a few nanoseconds. The dimensions of these quantum dots were well controlled to the precision of state-of-the-art fabrication technologies, as reflected in the uniformity of their optical properties. The yield of optically active quantum dots was greater than 90%, among which 13%-25% exhibited single photon emission at 10 K.

  20. Increased photon density of states at defect-mode frequencies led enhancement of tunability of spontaneous emission from Eu2+, 3+ doped SiO2/SnO2 one-dimensional photonic crystals

    NASA Astrophysics Data System (ADS)

    Das, Pratyusha; Maiti, Rishi; Ray, Samit K.; Shivakiran Bhaktha, B. N.

    2015-03-01

    One-dimensional photonic crystal (1DPhC) micro-cavity resonators, constituted of Eu2+, 3+ doped silica layer inserted between two 5-bilayered SiO2/SnO2 Bragg mirrors, are fabricated by sol–gel process. The 1DPhC exhibits a ?180 nm wide stop-band, with peak-reflectivity of more than 96%. Spectral modifications of the photonic stop-band by varying the angle of detection with respect to the sample surface normal are studied. With an increase in the detection angle from 0° to 45° the defect-mode continuously sweeps from 598.6 nm to 532.0 nm, selectively enhancing the coinciding Eu2+, 3+ emission. To quantify the increase in spontaneous emission at defect-mode frequencies, a relative enhancement factor is devised. The increased photon density of states at defect-mode frequencies is found to enhance the weak emission tail of Eu2+, 3+ ions by a factor of ?9.