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1

Controlled spontaneous emission in erbium-doped microphotonic materials  

E-print Network

Controlled spontaneous emission in erbium-doped microphotonic materials #12;Controlled spontaneous emission in erbium-doped microphotonic materials Jeroen Kalkman ISBN 90-393-0295-2 A digital version of this thesis can be downloaded from http://www.amolf.nl #12;Controlled spontaneous emission in erbium

Polman, Albert

2

Controlling spontaneous emission with plasmonic optical patch antennas  

E-print Network

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.

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

3

Ultrafast non-local control of spontaneous emission  

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

4

Ultrafast non-local control of spontaneous emission.  

PubMed

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

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

2014-11-01

5

Controlling spontaneous emission dynamics in semiconductor micro cavities  

NASA Astrophysics Data System (ADS)

Spontaneous emission of light can be controlled, cavity quantum electrodynamics tells us, and many experiments in atomic physics demonstrated this fact. In particular, coupling an emitter to a resonant photon mode of a cavity can enhance its spontaneous emission rate: this is the so-called Purcell effect. Though appealing it might seem to implement these concepts for the benefit of light-emitting semiconductor devices, great care has to be taken as to which emitter/cavity system should be used. Semiconductor quantum boxes prove to be good candidates for witnessing the Purcell effect. Also, low volume cavities having a high optical quality in other words a long photon storage time are required. State-of-the-art fabrication techniques of such cavities are presented and discussed.We demonstrate spontaneous emission rate enhancement for InAs/GaAs quantum boxes in time-resolved and continuous-wave photoluminescence experiments. This is done for two kinds of cavities, namely GaAs/AlAs micropillars (global enhancement by a factor of 5), and GaAs microdisks (global enhancement by a factor of 20). Prospects for lasers, light-emitting diodes and single photon sources based on the Purcell effect are discussed. L'émission spontanée de lumière peut être contrôlée, ainsi que nous l'enseigne l'électrodynamique quantique en cavité, ce fait a été démontré expérimentalement en physique atomique. En particulier, coupler un émetteur à un mode photonique résonnant d'une cavité peut exalter son taux d'émission spontanée : c'est l'effet Purcell. Bien qu'il semble très prometteur de mettre en pratique ces concepts pour améliorer les dispositifs semi-conducteurs émetteurs de lumière, le choix du système émetteur/cavité est crucial. Nous montrons que les boîtes quantiques semi-conductrices sont des bons candidats pour observer l'effet Purcell. Il faut par ailleurs des cavités de faible volume ayant une grande qualité optique en d'autres mots un long temps de stockage des photons. Des techniques de fabrication à l'état de l'art de telles cavités sont présentées et discutées.Nous démontrons une exaltation du taux d'émission spontanée pour des boîtes quantiques InAs/GaAs dans des expériences de photoluminescence résolues en temps et en continu. Ceci est réalisé pour deux types de cavités, à savoir des micropiliers GaAs/AlAs (exaltation globale par un facteur 5) et des microdisques (exaltation globale d'un facteur 20). Quelques perspectives pour l'application de l'effet Purcell à des lasers, des diodes électroluminescentes et des sources de photons uniques sont présentées et discutées.

Gayral, B.

6

Coherent control of spontaneous emission near a photonic band edge: A qubit for quantum computation  

E-print Network

­photon spontaneous emission @5#, classical light localization @6#, a photon­atom bound state @8#, fractionalized demonstrate the coherent control of spontaneous emission for a three­level atom located within a photonic band the three­level atom can be totally suppressed or strongly enhanced depending on the relative phase between

John, Sajeev

7

Coherent control of spontaneous emission near a photonic band edge: A qubit for quantum computation  

E-print Network

-photon spontaneous emission 5 , classical light localization 6 , a photon-atom bound state 8 , fractionalized single-atom demonstrate the coherent control of spontaneous emission for a three-level atom located within a photonic band the three-level atom can be totally suppressed or strongly enhanced depending on the relative phase between

John, Sajeev

8

Quantum control of population inversion in the presence of spontaneous emission  

E-print Network

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

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

2001-03-20

9

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

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

10

Two-dimensional sub-half-wavelength atom localization via controlled spontaneous emission.  

PubMed

We propose a scheme for two-dimensional (2D) atom localization based on the controlled spontaneous emission, in which the atom interacts with two orthogonal standing-wave fields. Due to the spatially dependent atom-field interaction, the position probability distribution of the atom can be directly determined by measuring the resulting spontaneously emission spectrum. The phase sensitive property of the atomic system leads to quenching of the spontaneous emission in some regions of the standing-waves, which significantly reduces the uncertainty in the position measurement of the atom. We find that the frequency measurement of the emitted light localizes the atom in half-wavelength domain. Especially the probability of finding the atom at a particular position can reach 100% when a photon with certain frequency is detected. By increasing the Rabi frequencies of the driving fields, such 2D sub-half-wavelength atom localization can acquire high spatial resolution. PMID:22273975

Wan, Ren-Gang; Zhang, Tong-Yi

2011-12-01

11

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

NASA Astrophysics Data System (ADS)

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.

Liu, Ronggang

2015-01-01

12

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

PubMed

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

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

2012-03-26

13

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

PubMed Central

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

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

2014-01-01

14

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

E-print Network

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 ...

Gan, Xuetao

15

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

PubMed Central

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

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

16

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

PubMed

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

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

2013-10-28

17

Controlling the 1 ?m spontaneous emission in Er/Yb co-doped fiber amplifiers.  

PubMed

In this paper we present our experimental studies on controlling the amplified spontaneous emission (ASE) from Yb(3+) ions in Er/Yb co-doped fiber amplifiers. We propose a new method of controlling the Yb-ASE by stimulating a laser emission at 1064 nm in the amplifier, by providing a positive 1 ?m signal feedback loop. The results are discussed and compared to a conventional amplifier setup without 1 ?m ASE control and to an amplifier with auxiliary 1064 nm seeding. We have shown, that applying a 1064 nm signal loop in an Er/Yb amplifier can increase the output power at 1550 nm and provide stable operation without parasitic lasing at 1 ?m. PMID:21996851

Sobon, Grzegorz; Kaczmarek, Pawel; Antonczak, Arkadiusz; Sotor, Jaroslaw; Abramski, Krzysztof M

2011-09-26

18

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

NASA Astrophysics Data System (ADS)

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.

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

2015-03-01

19

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

SciTech Connect

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.

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

20

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

E-print Network

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.

Zheng Liu; Wei Li; Xunya Jiang

2012-03-03

21

Evidence for confined tamm plasmon modes under metallic microdisks and application to the control of spontaneous optical emission.  

PubMed

We demonstrate strong confinement of the optical field by depositing a micron sized metallic disk on a planar distributed Bragg reflector. Confined Tamm plasmon modes are evidenced both experimentally and theoretically, with a lateral confinement limited to the disk area and strong coupling to TE polarized fields. Single quantum dots controllably coupled to these modes are shown to experience acceleration of their spontaneous emission when spectrally resonant with the mode. For quantum dots spectrally detuned from the confined Tamm plasmon mode, an inhibition of spontaneous emission by a factor 40±4 is observed, a record value in the optical domain. PMID:22243024

Gazzano, O; Michaelis de Vasconcellos, S; Gauthron, K; Symonds, C; Bloch, J; Voisin, P; Bellessa, J; Lemaître, A; Senellart, P

2011-12-01

22

Control of Spontaneous Emission from a Microwave Field Coupled Five-Level M-type Atom in Photonic Crystals  

NASA Astrophysics Data System (ADS)

We investigate the spontaneous emission spectrum of a five-level M-type atom driven by a microwave field, in which one lower level is coupled by the same modified reservoir to two upper levels. The results show that a few interesting phenomena in spontaneous emission spectra, such as spectral-line shift, spectral-line enhancement and spectral-line suppression, which can be controlled by adjusting the proper parameters of the system. These phenomena can originate from quantum interference of the strong coupling system.

Liu, Ronggang

2014-12-01

23

Optical antenna enhanced spontaneous emission  

PubMed Central

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

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

2015-01-01

24

Laser Cooling without Spontaneous Emission  

NASA Astrophysics Data System (ADS)

This Letter reports the demonstration of laser cooling without spontaneous emission, and thereby addresses a significant controversy. It works by restricting the atom-light interaction to a time short compared to a cycle of absorption followed by natural decay. It is achieved by using the bichromatic force on an atomic transition with a relatively long excited state lifetime and a relatively short cooling time so that spontaneous emission effects are minimized. The observed width of the one-dimensional velocity distribution is reduced by ×2 thereby reducing the "temperature" by ×4 . Moreover, our results comprise a compression in phase space because the spatial expansion of the atomic sample is limited. This accomplishment is of interest to direct laser cooling of molecules or in experiments where working space or time is limited.

Corder, Christopher; Arnold, Brian; Metcalf, Harold

2015-01-01

25

VOLUME 79, NUMBER 26 P HY S I CA L REV I EW L E T T ER S 29 DECEMBER 1997 Coherent Control of Spontaneous Emission near a Photonic Band Edge  

E-print Network

of Spontaneous Emission near a Photonic Band Edge: A Single­Atom Optical Memory Device Tran Quang, Mesfin demonstrate coherent control of spontaneous emission from a three­level atom with one resonant frequency near the edge of a photonic band gap. As a result of quantum interference and photon localization, spontaneous

John, Sajeev

26

VOLUME 79, NUMBER 26 P H Y S I C A L R E V I E W L E T T E R S 29 DECEMBER 1997 Coherent Control of Spontaneous Emission near a Photonic Band Edge  

E-print Network

of Spontaneous Emission near a Photonic Band Edge: A Single-Atom Optical Memory Device Tran Quang, Mesfin demonstrate coherent control of spontaneous emission from a three-level atom with one resonant frequency near the edge of a photonic band gap. As a result of quantum interference and photon localization, spontaneous

John, Sajeev

27

Spontaneous Photon Emission in Cavities  

E-print Network

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.

Gernot Alber; Nils Trautmann

2014-12-04

28

Inhibited spontaneous emission in solid-state physics and electronics  

Microsoft Academic Search

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

Eli Yablonovitch

1987-01-01

29

InAs quantum boxes in GaAs/AlAs pillar microcavities: from spectroscopic investigations to spontaneous emission control  

NASA Astrophysics Data System (ADS)

GaAs/AlAs pillar microcavities containing an array of InAs quantum boxes in their core region have been fabricated by molecular beam epitaxy, electron-beam lithography and reactive ion etching. By placing this broadband light emitter in the cavity, we can probe precisely by photoluminescence the modal structure of the micropillars. After having validated this approach through the study of circular pillars, we address two important issues in context of spontaneous emission control. We show first that it is possible, by choosing an elliptical cross-section, to lift the polarization degeneracy of the fundamental mode of circular micropillars. By measuring Purcell’s factor for small pillars containing quantum boxes, we then highlight their potential for observing large cavity quantum electrodynamic effects in the weak coupling regime, which is confirmed by recent preliminary time-resolved experiments.

Gérard, J. M.; Legrand, B.; Gayral, B.; Costard, E.; Sermage, B.; Kuszelewicz, R.; Barrier, D.; Thierry-Mieg, V.; Rivera, T.; Marzin, J. Y.

1998-07-01

30

Tuneability of amplified spontaneous emission through control of the waveguide-mode structure in conjugated polymer films  

NASA Astrophysics Data System (ADS)

We show that the position of the amplified spontaneous emission (ASE) in poly[2-methoxy-5(2'-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV) can be controlled by the effect of the film thickness on waveguide modes. We demonstrate that the ASE can be tuned over 31 nm corresponding to a gain bandwidth of 25 THz. By modeling the waveguide modes we find that the ASE position for films thinner than 76 nm is determined by the cutoff wavelength for the waveguide and is shifted to shorter wavelengths with decreasing film thickness. We also demonstrate a simple method for measuring the cutoff wavelength and show that this correlates well with calculated values.

Sheridan, A. K.; Turnbull, G. A.; Safonov, A. N.; Samuel, I. D. W.

2000-11-01

31

Control of spontaneous emission from a microwave-field-coupled three-level{Lambda}-type atom in photonic crystals  

SciTech Connect

The spontaneous emission spectrum of a three-level {Lambda}-type atom driven by a microwave field was studied. For the two transitions coupled to the same modified reservoir, we discussed the influence of photonic band gap and Rabi frequency of the microwave field on the emission spectrum. The emission spectrum is given for different locations of the upper band-edge frequency. With the transition frequencies moving from outside the band gap to inside, the number of peaks decreases in the emission spectrum and the multipeak structure of spectral line is finally replaced by a strong non-Lorentzian shape. With increase of the Rabi frequency of the microwave field, we find the spectral line changes from a multipeak structure to a two-peak structure, originating from the inhibition of spontaneous emission for the corresponding decay channel.

Jiang, X. Q.; Zhang, B.; Sun, X. D. [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Lu, Z. W. [National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin 150001 (China)

2011-05-15

32

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

E-print Network

to thank my family. I appreciate my parents for their unconditional and endless love and support. I wish to thank my wife Siyi for her assistance and faith in me. Their constant support make what I am today. v TABLE OF CONTENTS Page ABSTRACT... describes the process that an excited light source such as an atom, jumps to a lower energy state and emit a photon, stimulated the birth of modern quantum mechanics and quantum electrodynamics. It is shown that quantum interference can lead to 1 spontaneous...

Yang, Shuai

2013-12-12

33

Plasmon-induced modifications in spontaneous emission of fluorophores in controlled nanoscale geometries  

NASA Astrophysics Data System (ADS)

It is well known that a variety of fundamental photophysical processes, such as absorption, fluorescence, and Raman scattering, are greatly substantially modified in the vicinity of metal surfaces or structures such as gratings, island films or colloids. [1] The collective electromagnetic resonances, or plasmon resonances, supported by metallic structures, as well as modifications in the local electromagnetic mode density near these structures, are responsible for influencing the radiating dipole of vicinal fluorophores. Nanoshells are dielectric core-metal shell nanoparticles whose plasmon resonance can be controllably tuned by varying the relative dimensions of its core and shell layers [2]. Nanoshells provide a practical substrate for the systematic investigation of the role of the plasmon-induced near field in fluorescence enhancement and quenching. We have fabricated two systems for the study of lanthanide ions and molecular fluorophores, respectively, at controlled distances above a nanoshell surface. Initial results examining the fluorophore-metal distance dependence and dependence on plasmon resonance detuning with respect to excitations in the fluorophore will be discussed. [1] Moskovits, M., Rev. Mod. Phys. 57, 783 (1985) [2] S. Oldenburg, R. D. Averitt, S. Westcott, and N. J. Halas, Chem. Phys. Lett. 288, 243 (1998); E. Prodan, C. Radloff, N. J. Halas and P. J. Nordlander, Science 301, 419 (2003).

Lal, Surbhi; Goodrich, Glenn P.; Brinson, Bruce E.; Halas, N. J.

2004-03-01

34

Cavity enhanced rephased amplified spontaneous emission  

E-print Network

Amplified spontaneous emission is usually treated as an incoherent noise process. Recent theoretical and experimental work using rephasing optical pulses has shown that rephased amplified spontaneous emission (RASE) is a potential source of wide bandwidth time-delayed entanglement. Due to poor echo efficiency the plain RASE protocol doesn't in theory achieve perfect entanglement. Experiments done to date show a very small amount of entanglement at best. Here we show that rephased amplified spontaneous emission can, in principle, produce perfect multimode time-delayed two mode squeezing when the active medium is placed inside a Q-switched cavity.

Lewis A Williamson; Jevon J Longdell

2014-05-20

35

Blue shift of spontaneous emission in hyperbolic metamaterial.  

PubMed

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

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

2014-01-01

36

Ongoing Spontaneous Activity Controls Access to Consciousness  

E-print Network

Ongoing Spontaneous Activity Controls Access to Consciousness: A Neuronal Model for Inattentional of endogenous states of consciousness, and particularly the blocking of access to consciousness that occurs of consciousness. Citation: Dehaene S, Changeux JP (2005) Ongoing spontaneous activity controls access

Paris-Sud XI, Université de

37

Cooperative spontaneous emission of three identical atoms  

E-print Network

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.

Wei Feng; Yong Li; Shi-Yao Zhu

2013-02-06

38

Spontaneous emission from free electron lasers  

SciTech Connect

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.

Schmitt, M.J.

1991-01-01

39

Spontaneous emission from a fractal vacuum  

NASA Astrophysics Data System (ADS)

Spontaneous emission of a quantum emitter coupled to a QED vacuum with a deterministic fractal structure of its spectrum is considered. We show that the decay probability does not follow a Wigner-Weisskopf exponential decrease but rather an overall power law behavior with a rich oscillatory structure, both depending on the local fractal properties of the vacuum spectrum. These results are obtained by giving first a general perturbative derivation for short times. Then we propose a simplified model which retains the main features of a fractal spectrum to establish analytic expressions valid for all time scales. Finally, we discuss the case of a Fibonacci cavity and its experimental relevance to observe these results.

Akkermans, Eric; Gurevich, Evgeni

2013-08-01

40

L-band automatic-gain-controlled erbium-doped fiber amplifier utilizing C-band backward-amplified spontaneous emission and electrical feedback monitor.  

PubMed

A new L-band automatic-gain-controlled (AGC) erbium-doped fiber amplifier (EDFA) for dense wavelength-division-multiplexing transmission systems is presented, in which a single 1480 nm laser with an internal thermoelectric cooler is used as a primary pump for stable amplification. All C-band amplified spontaneous emission (ASE) is recycled by the secondary pump to enhance the gain efficiency. A fraction of the output signal is used as an electrical feedback monitor for the AGC to improve the gain-clamped (GC) flatness. Experimental results prove that the AGC EDFA has a gain flatness of better than 0.46 dB/40 nm, i.e., below 1.5%, and a higher gain of approximately 36.5 dB compared to that of approximately 35.3 dB for the conventional GC EDFA at -30 dBm input signal power. The best gain flatness of +/-0.25 dB can be achieved over the dynamic range greater than 20 dB. The dynamic range of noise figure is between 6.7 and 7.1. The 3 dB down bandwidth is more than 40 nm. Overall dynamics measurements for the AGC EDFA feedback stabilization have been carried out. The recorded corresponding rise time of 1.565 ms indicates that the system does not exhibit any overshoot of gain or ASE variation due to the signal at the beginning of the pulse. PMID:19209194

Shen, Jyi-Lai; Lee, Yueh-Chien; Huang, Chia-Chih

2009-02-10

41

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

E-print Network

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

42

Characterization of semiconductor lasers by spontaneous emission measurements  

Microsoft Academic Search

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

F. Girardin; Guang-Hua Duan

1997-01-01

43

Modified spontaneous emissions of europium complex in weak PMMA opals.  

PubMed

Engineering spontaneous emission by means of photonic crystals (PHC) is under extensive study. However PHC modification of line emissions of rare earth (RE) ions has not been thoroughly understood, especially in cases of weak opal PHCs and while emitters are well dispersed into dielectric media. In this study, poly-methyl methacrylate (PMMA) opal PHCs containing uniformly dispersed europium chelate were fabricated with finely controlled photonic stop band (PSB) positions. Measurements of luminescent dynamics and angle resolved/integrated emission spectra as well as numerical calculations of total densities of states (DOS) were performed. We determined that in weak opals, the total spontaneous emission rate (SER) of ?(5)D(0)-(7)F(J) for Eu(3+) was independent of PSB positions but was higher than that of the disordered powder sample, which was attributed to higher effective refractive indices in the PHC rather than PSB effect. Branch SER of (5)D(0)-(7)F(2) for Eu(3+) in the PHCs, on the other hand, was spatially redistributed, suppressed or enhanced in directions of elevated or reduced optical modes, keeping the angle-integrated total unchanged. All the results are in agreement with total DOS approximation. Our paper addressed two unstudied issues regarding modified narrow line emission in weak opal PHCs: firstly whether PSB could change the SER of emitters and whether there exist, apart from PSB, other reasons to change SERs; secondly, while directional enhancement and suppression by PSB has been confirmed, whether the angle-integrated overall effect is enhancing or suppressing. PMID:21938288

Wang, Wei; Song, Hongwei; Bai, Xue; Liu, Qiong; Zhu, Yongsheng

2011-10-28

44

The Effect of Contralateral Acoustic Stimulation on Spontaneous Otoacoustic Emissions  

PubMed Central

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

Dhar, Sumitrajit

2009-01-01

45

Quantitative analysis of directional spontaneous emission spectra from light sources in photonic crystals  

SciTech Connect

We have performed angle-resolved measurements of spontaneous-emission spectra from laser dyes and quantum dots in opal and inverse opal photonic crystals. Pronounced directional dependencies of the emission spectra are observed: angular ranges of strongly reduced emission adjoin with angular ranges of enhanced emission. It appears that emission from embedded light sources is affected both by the periodicity and by the structural imperfections of the crystals: the photons are Bragg diffracted by lattice planes and scattered by unavoidable structural disorder. Using a model comprising diffuse light transport and photonic band structure, we quantitatively explain the directional emission spectra. This work provides detailed understanding of the transport of spontaneously emitted light in real photonic crystals, which is essential in the interpretation of quantum optics in photonic-band-gap crystals and for applications wherein directional emission and total emission power are controlled.

Nikolaev, Ivan S.; Lodahl, Peter; Vos, Willem L. [Complex Photonic Systems (COPS), Department of Science and Technology, and MESA Institute of Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)

2005-05-15

46

Reversible Modulation of Spontaneous Emission by Strain in Silicon Nanowires  

PubMed Central

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

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

2012-01-01

47

Large spontaneous emission rate enhancement in grating coupled hyperbolic metamaterials.  

PubMed

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

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

2014-01-01

48

Spontaneous two-photon emission from a single quantum dot.  

PubMed

Spontaneous two-photon emission from a solid-state single quantum emitter is observed. We investigated photoluminescence from the neutral biexciton in a single semiconductor quantum dot coupled with a high Q photonic crystal nanocavity. When the cavity is resonant to the half energy of the biexciton, the strong vacuum field in the cavity inspires the biexciton to simultaneously emit two photons into the mode, resulting in clear emission enhancement of the mode. Meanwhile, the suppression of other single photon emission from the biexciton was observed, as the two-photon emission process becomes faster than the others at the resonance. PMID:22182088

Ota, Yasutomo; Iwamoto, Satoshi; Kumagai, Naoto; Arakawa, Yasuhiko

2011-12-01

49

Spontaneous Radio Frequency Emissions from Natural Aurora. Chapter 4  

NASA Technical Reports Server (NTRS)

At high latitudes, suitably sensitive radio experiments tuned below 5 MHz detect up to three types of spontaneous radio emissions from the Earth s ionosphere. In recent years, ground-based and rocket-borne experiments have provided strong evidence for theoretical explanations of the generation mechanism of some of these emissions, but others remain unexplained. Achieving a thorough understanding of these ionospheric emissions, accessible to ground-based experiments, will not only bring a deeper understanding of Earth s radio environment and the interactions between waves and particles in the ionosphere but also shed light on similar spontaneous emissions occurring elsewhere in Earth s environment as well as other planetary and stellar atmospheres.

LaBelle, J.

2009-01-01

50

Random Number Generation Using Amplified Spontaneous Emission in a Fiber Amplifier  

E-print Network

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

Anlage, Steven

51

Spontaneous emission in a silicon charge qubit  

E-print Network

The interaction between a qubit and its environment provides a channel for energy relaxation which has an energy-dependent timescale governed by the specific coupling mechanism. We measure the rate of inelastic decay in a Si MOS double quantum dot (DQD) charge qubit through sensing the charge state's response to non-adiabatic driving of its excited state population. The charge distribution is sensed remotely in the weak measurement regime. We extract emission rates down to kHz frequencies by measuring the variation of the non-equilibrium charge occupancy as a function of amplitude and dwell times between non-adiabatic pulses. Our measurement of the energy-dependent relaxation rate provides a fingerprint of the relaxation mechanism, indicating that relaxation rates for this Si MOS DQD are consistent with coupling to deformation acoustic phonons.

Khoi T. Nguyen; N. Tobias Jacobson; Michael P. Lilly; Nathaniel C. Bishop; Erik Nielsen; Joel R. Wendt; J. Dominguez; T. Pluym; Malcolm S. Carroll

2014-03-14

52

A hybrid nanoantenna for highly enhanced directional spontaneous emission  

SciTech Connect

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.

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

53

Are Einstein's transition probabilities for spontaneous emission constant in plasmas?  

NASA Technical Reports Server (NTRS)

An investigation is conducted with a ruby laser to experimentally confirm the quenching of spontaneous emission coefficients and propose a mechanism for the phenomenon. Results of previous experiments are examined to determine the consistency and validity of interpretations of the spontaneous emissions. For the C IV 3s-3p and 2s-3p transitions, the line-intensity ratios are found to be dependent on the separation of the laser from the target. Density gradients and Stark broadening are proposed to interpret the results in a way that does not invalidate the Einstein A values. The interpretation is extended to C III and N V, both of which demonstrate similar changes in A values in previous experiments. The apparent quenching of Ar II by photon collisions is explained by Rabi oscillations and power broadening in the argon-ion laser cavity. It is concluded that the changes in A values cannot result from dense plasma effects.

Griem, H. R.; Huang, Y. W.; Wang, J.-S.; Moreno, J. C.

1991-01-01

54

Lasing and modified spontaneous emission in photonic crystal structures and microcavities  

NASA Astrophysics Data System (ADS)

Semiconductor light-emitting devices in the near-infrared (1.55 ?m) based on microfabricated photonic crystal structures are demonstrated. The photonic structures consist of two-dimensional arrays of air holes patterned into an optically thin, air-suspended InGaAsP slab by high-resolution electron beam lithography and various dry etching techniques. Two types of microcavities are examined. The first are larger hexagonally shaped cavities in the range of 10 to 20 ?m in size and bounded by the photonic crystal structure. Cavity mode spontaneous emission at room temperature under optical pumping is used to demonstrate mode confinement due to the in-plane bandgap. No cavity mode peaks in the emission spectrum are seen if the in- plane bandgap is not spectrally aligned with the material emission. Pulsed lasing is also demonstrated with the lasing threshold at 66 mW peak incident optical pump power at a duty cycle of less than 1% in order to minimize membrane heating. Changes in the pump geometry is shown to result in controllable lasing mode switching. This behaviour is explained in terms of mode Q, lasing threshold and enhanced spontaneous emission into the mode. The second type of microcavity consists of a single point defect into photonic lattice with a modal volume of 2.5(l/2n) 3~0.03mm3. Cavity quality factors up to 250 are demonstrated and suppressed spontaneous emission due to the bandgap except at the mode frequency is shown. Pulsed lasing at 143 K under optical pumping is demonstrated. The fundamental modification of the spontaneous emission rate due to the in-plane bandgap, in a photonic crystal slab structure with no microcavity is experimentally and numerically examined. Incomplete bandgaps are theoretically shown to be able to strongly inhibit spontaneous emission. High density of states points in the bandstructure are seen to greatly enhance the spontaneous emission rate. Measurements using phase sensitive spectroscopy of the spontaneous emission rate from quantum wells in the photonic crystal slab show a greater than 10 times inhibition of the emission rate in the in-plane bandgap. Experimental evidence for saturation of the surface recombination at relatively low pumping levels is found.

Lee, Reginald Kai Ming

2000-11-01

55

Spontaneous UV-emission from nitrogen and rare-gas halogen excimers in a fast-flowing crossed-beam plasma-mixing device for pollution control  

SciTech Connect

Air pollution, water (under ground or ground), and soil contamination have become major issues with increasing industrialization. In addition to conventional incineration techniques, non-thermal plasma techniques and photolysis have been demonstrated to be very powerful tools converting pollutants into harmless chemicals. The use of excimer lamps for pollution control provides an important advantage. Emission spectrum of excimer molecules depends on the type of the gas molecules in the discharge tube forming the particular excimer molecule. Therefore, by choosing the adequate gas mixture, an emission may be found which coincides with the absorption maximum of the pollutant. One other advantage of using excimer lamps is the high efficiency of these lamps in the UV region compared to the conventional lamps. The photon energy efficiency of an excimer lamp can be as high as 10% depending on the design. The authors have developed the technique of fast plasma mixing which overcomes some of the disadvantages of excimer generation in a glow discharge, or in an electron beam sustained gas discharge, and offers an effective way to generate continuous wave UV radiation. This technique utilizes near resonant energy and charge transfer from metastable rare gas atoms and ions to molecules. A fast-flowing crossed-beam plasma mixing device can be utilized to obtain high efficiency UV lamps for industrial use. In this work, basic concepts of the crossed-beam plasma-mixing device operation are presented.

Kirkici, H.; Kralovec, J. [Auburn Univ., AL (United States). Electrical Engineering Dept.

1995-12-31

56

Spontaneous emission and energy transfer rates near a coated metallic cylinder  

NASA Astrophysics Data System (ADS)

The spontaneous emission and energy transfer rates of quantum systems in proximity to a dielectrically coated metallic cylinder are investigated using a Green's tensor formalism. The excitation of surface plasmon modes can significantly modify these rates. The spontaneous emission and energy transfer rates are investigated as a function of the material and dimensions of the core and coating, as well as the emission wavelength of the donor. For the material of the core we consider gold and silver, whose surface plasmon wavelengths lie in the visible part of the electromagnetic spectrum. The spontaneous emission rate is enhanced by several orders of magnitude when the emission wavelength is close to the surface plasmon wavelength. The energy transfer rate enhancement is found to be concentrated in hot spots around the circumference of the coated cylinder. Introducing the energy transfer efficiency as a parameter, we find that, when the donor emission and acceptor absorption spectra are resonant with the surface plasmon modes excited on the coated cylinder, the energy transfer efficiency can be significantly enhanced compared to the off-resonance situation. Tuning the surface plasmon wavelength to the emission wavelength of the donor via the geometrical and material parameters of the coated cylinder allows, therefore, control of the energy transfer efficiency.

Karanikolas, Vasilios; Marocico, Cristian A.; Bradley, A. Louise

2014-06-01

57

Interference-induced splitting of resonances in spontaneous emission  

E-print Network

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

R. Arun

2007-10-06

58

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

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

59

Insect spontaneous ultraweak photon emission as an indicator of insecticidal compounds.  

PubMed

The influence of beta-cypermethrin, a commercial insecticide, and Cicuta virosa L. var. latisecta Celak (Umbelliferae:Cicutal), an insecticidal plant, on the spontaneous ultraweak photon emissions from larvae of Spodoptera litura Fabricius and Zophobas morio Fabricius were studied. The increased percentages of spontaneous photon emission intensities from S. litura treated with 0.1 and 1 ?g/ml beta-cypermethrin were both lower than those of the control in the 24 post-treatment hours, remarkable difference could also be observed during the same period from Z. morio treated with beta-cypermethrin at 0.156, 0.313 and 0.625 ?g/ml. The increased percentages of spontaneous photon emission intensities from the two mentioned insects treated with 10,100 and 1000 ?g/ml petroleum ether fraction of C. virosa L. var. latisecta, which displayed little activity against whole insects, could also be changed noticeably. The present study indicated that change in the intensity of spontaneous ultraweak photon emission from insect could be used as a novel method for screening insecticidal compounds with very low content in plant. PMID:25108203

Tian, Yongqing; Yang, Chuping; Xu, Hanhong

2014-11-01

60

Spontaneous emission from the C3 radical in carbon plasma.  

PubMed

Spontaneous emission measurements are discussed for the Swings transitions of the C(3) radical in laser-generated graphite plasma, and the spectroscopy of the C(3) radical in carbon vapor and plasma is summarized. A review is given of some theoretical calculations and emission spectroscopic investigations are presented. Time-averaged, laser-induced optical breakdown spectra are reported from Nd:YAG laser generated graphite microplasma. In 200-300 Torr of argon and helium, and depending on the specific experimental configuration, a weak emission continuum is observed centered at 400 nm when using a laser fluence of typically 1 J/cm(2). Such continua were not detected in our previous experiments using focused laser radiation. The possibilities for the origin of this continuum are considered. PMID:17571143

Nemes, László; Keszler, Anna M; Parigger, Christian G; Hornkohl, James O; Michelsen, Hope A; Stakhursky, Vadim

2007-07-01

61

Plasmonic nanogaps for broadband and large spontaneous emission rate enhancement  

NASA Astrophysics Data System (ADS)

We present the optical properties of a plasmonic nanogap formed between a silver metallic nanoparticle and an extended silver film that shows a strong enhancement in the spontaneous emission rate over the whole visible range. In particular, we use three-dimensional finite difference time domain calculations to study the spontaneous emission rate and the quantum efficiency of an emitting material placed within the gap region as a function of the geometrical parameters of the plasmonic nanogap. Our calculations reveal that the enhancements in the total decay rate can be divided into two regions as a function of wavelength; region I spans the wavelength range from 350 nm to 500 nm and peaks at approximately at 400 nm. Region II covers the spectral range between 500 nm and 1000 nm. The enhancements in total decay rate in region I are mainly dominated by Ohmic losses by the metal, while the enhancements in total decay rate in region II are mainly dominated by radiative decay rate enhancements. Furthermore, our calculations show over 100 times enhancement in the spontaneous emission rate in region II. We combine this with quantum efficiency enhancements of almost 30 times from materials with low intrinsic quantum efficiencies and only a small reduction in efficiency from those with high intrinsic quantum efficiencies. All results appear easily achievable using realistic geometrical parameters and simple synthesis techniques. These results are attributed to the strong field confinements in the nanogap region. The structures are of high interest for both the fundamental understanding of light mater interactions under extreme electromagnetic field confinements and also potential applications in quantum optics and Raman spectroscopy.

Edwards, Anthony P.; Adawi, Ali M.

2014-02-01

62

Plasmonic nanogaps for broadband and large spontaneous emission rate enhancement  

SciTech Connect

We present the optical properties of a plasmonic nanogap formed between a silver metallic nanoparticle and an extended silver film that shows a strong enhancement in the spontaneous emission rate over the whole visible range. In particular, we use three-dimensional finite difference time domain calculations to study the spontaneous emission rate and the quantum efficiency of an emitting material placed within the gap region as a function of the geometrical parameters of the plasmonic nanogap. Our calculations reveal that the enhancements in the total decay rate can be divided into two regions as a function of wavelength; region I spans the wavelength range from 350?nm to 500?nm and peaks at approximately at 400?nm. Region II covers the spectral range between 500?nm and 1000?nm. The enhancements in total decay rate in region I are mainly dominated by Ohmic losses by the metal, while the enhancements in total decay rate in region II are mainly dominated by radiative decay rate enhancements. Furthermore, our calculations show over 100 times enhancement in the spontaneous emission rate in region II. We combine this with quantum efficiency enhancements of almost 30 times from materials with low intrinsic quantum efficiencies and only a small reduction in efficiency from those with high intrinsic quantum efficiencies. All results appear easily achievable using realistic geometrical parameters and simple synthesis techniques. These results are attributed to the strong field confinements in the nanogap region. The structures are of high interest for both the fundamental understanding of light mater interactions under extreme electromagnetic field confinements and also potential applications in quantum optics and Raman spectroscopy.

Edwards, Anthony P.; Adawi, Ali M., E-mail: a.adawi@hull.ac.uk [Department of Physics and Mathematics, University of Hull, Cottingham Road, Hull HU6 7RX (United Kingdom)

2014-02-07

63

Continuous-variable entanglement in a correlated spontaneous emission laser  

E-print Network

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

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

2005-01-01

64

Optical instabilities and spontaneous light emission by polarizable moving matter  

E-print Network

One of the most extraordinary manifestations of the coupling of the optical field and matter is the emission of light by charged particles passing through a dielectric medium: the Vavilov-Cherenkov effect. In this article, it is theoretically predicted that a related phenomenon may be observed when neutral fast polarizable particles travel near a metal surface supporting surface plasmon polaritons. Rather dramatically, it is found that at some critical velocity, even if the initial optical field is vanishingly small, the system may become unstable and may start spontaneously emitting light such that in some initial time window the optical field grows exponentially with time.

Mario G. Silveirinha

2014-06-10

65

Computation of spontaneous emission dynamics in colored vacua  

E-print Network

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

Mohammad Hosain Teimourpour; Ramy El-Ganainy

2014-12-25

66

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

PubMed

This month's featured review article; "Ultraweak, spontaneous photon emission in seedlings: toxicological and chronobiological applications" is authored by Cristiano de Mello Gallep. The mini-review presents the use of ultra-weak photon emission (UPE) emitted by seedlings in toxicological and chronobiological applications. Chronic and acute stress induces pattern changes in UPE, giving a new parameter for real-time analysis of germination tests. The UPE time profile for a single seedling is shown for the first time, with pronounced circadian cycles in synchronism with the local gravimetric tide. The cover of this issue of Luminescence features the measuring of UPE time profile emitted by a single sunflower seedling, shown superposed to the local gravimetric tide, dg; also the UPE total counts x germination rate for samples stressed by wastewater sediment solutions. PMID:25511676

de Mello Gallep, Cristiano

2014-12-01

67

Amplified spontaneous emission properties of semiconducting organic materials.  

PubMed

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

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

2010-01-01

68

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

E-print Network

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.

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

2013-08-15

69

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

ERIC Educational Resources Information Center

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…

Snihur, Adrian W. K.; Hampson, Elizabeth

2011-01-01

70

Enhanced spontaneous emission from nanodiamond colour centres on opal photonic crystal  

E-print Network

Colour centres in diamond are promising candidates as a platform for quantum technologies and biomedical imaging based on spins and/or photons. Controlling the emission properties of colour centres in diamond is a key requirement for developing efficient single photon sources with high collection efficiency. A number of groups have produced enhancement in the emission rate over narrow wavelength ranges by coupling single emitters in nanodiamond crystals to resonant electromagnetic structures. Here we characterise in detail the spontaneous emission rates of nitrogen-vacancy centres positioned in various locations on a structured substrate. We show an average factor of 1.5 enhancement of the total emission rate when nanodiamonds are on an opal photonic crystal surface, and observe changes in the lifetime distribution. We present a model to explain these observations and associate the lifetime properties with dipole orientation and polarization effects.

Inam, Faraz A; Bradac, Carlo; Stewart, Luke; Withford, Michael J; Dawes, Judith M; Rabeau, James R; Steel, Michael J

2011-01-01

71

Enhanced spontaneous emission from nanodiamond colour centres on opal photonic crystal  

E-print Network

Colour centres in diamond are promising candidates as a platform for quantum technologies and biomedical imaging based on spins and/or photons. Controlling the emission properties of colour centres in diamond is a key requirement for developing efficient single photon sources with high collection efficiency. A number of groups have produced enhancement in the emission rate over narrow wavelength ranges by coupling single emitters in nanodiamond crystals to resonant electromagnetic structures. Here we characterise in detail the spontaneous emission rates of nitrogen-vacancy centres positioned in various locations on a structured substrate. We show an average factor of 1.5 enhancement of the total emission rate when nanodiamonds are on an opal photonic crystal surface, and observe changes in the lifetime distribution. We present a model to explain these observations and associate the lifetime properties with dipole orientation and polarization effects.

Faraz A Inam; Torsten Gaebel; Carlo Bradac; Luke Stewart; Michael J Withford; Judith M Dawes; James R Rabeau; Michael J Steel

2011-02-02

72

Atomic Dipole Traps with Amplified Spontaneous Emission: A Proposal  

E-print Network

We propose what we believe to be a novel type of optical source for ultra-cold atomic Far Off-Resonance optical-dipole Traps (FORTs). The source is based on an Erbium Amplified Spontaneous Emission (ASE) source that seeds a high power Erbium Doped Fiber Amplifier (EDFA). The main interest of this source is its very low coherence length, thus allowing an incoherent superposition of several trapping beams without any optical interference. The behavior of the superimposed beams is then a scalar sum greatly simplifying complex configurations. As an illustration, we report an estimation of the intensity noise of this source and an estimation of the atomic excess heating rate for an evaporative cooling experiment application. They are both found to be suitable for cold atoms experiments.

Jean-François Clément; Véronique Zehnlé; Jean Claude Garreau; Pascal Szriftgiser

2010-08-04

73

Spatial Pauli blocking of spontaneous emission in optical lattices  

SciTech Connect

Spontaneous emission by an excited fermionic atom can be suppressed due to the Pauli exclusion principle if the relevant final states after the decay are already occupied by identical atoms in the ground state. Here we discuss a setup where a single atom is prepared in the first excited state on a single site of an optical lattice under conditions of very tight trapping. We investigate these phenomena in the context of two experimental realizations: (1) with alkali-metal atoms, where the decay rate of the excited state is large, and (2) with alkaline-earth-metal-like atoms, where the decay rate from metastable states can be tuned in experiments. This phenomenon has potential applications towards reservoir engineering and dissipative many-body state preparation in an optical lattice.

Sandner, R. M.; Zoller, P. [Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck (Austria); Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck (Austria); Mueller, M. [Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck (Austria); Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck (Austria); Departamento de Fisica Teorica I, Universidad Complutense, E-28040 Madrid (Spain); Daley, A. J. [Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck (Austria); Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck (Austria); Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States)

2011-10-15

74

WDM optical steganography based on amplified spontaneous emission noise.  

PubMed

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

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

2014-10-15

75

Optical steganography based on amplified spontaneous emission noise.  

PubMed

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

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

2013-01-28

76

Engine emission control device  

Microsoft Academic Search

An air pollution control device is described for use with automobile engines for filtering crankcase and exhaust emissions. The device comprises a filtering chamber containing fluid coated filtering material having an inlet of a first diameter, an outlet of a second, larger diameter to cause a decrease in internal pressure of the air-pollutant mixture entering through the inlet, a controlled

1980-01-01

77

Random Number Generation Using Amplified Spontaneous Emission in a Fiber Amplifier  

E-print Network

Random Number Generation Using Amplified Spontaneous Emission in a Fiber Amplifier Julia C. Salevan methods including photon counting and chaotic systems. · We examine an optical system using the amplified spontaneous emission in a fiber amplifier as our random source. System Conclusions and Future Work Statistical

Anlage, Steven

78

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

PubMed

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

Wang, Yang-Yang; Zhang, Tong

2014-01-01

79

Automotive Emission Control.  

ERIC Educational Resources Information Center

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…

Lee, Billy D.; And Others

80

Automotive Emission Control.  

ERIC Educational Resources Information Center

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…

Lee, Billy D.; Ragazzi, Ronald

81

Emission control apparatus  

Microsoft Academic Search

This patent describes an improved emission control apparatus for use with an internal combustion engine. It comprises: the apparatus having an enclosed cylindrical housing with an inlet at one end thereof for connection with the exhaust of the engine and an outlet at the opposite end thereof; converter means being mounted in the housing for reducing noxious gases emitted from

1991-01-01

82

Vacuum field energy and spontaneous emission in anomalously dispersive cavities  

SciTech Connect

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.

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

2011-05-15

83

Power Penalty From Amplified Spontaneous Emission in Spatial Diversity Links for Fade Mitigation  

E-print Network

We investigate the power penalty caused by excess amplified spontaneous emission in an optically preamplified receiver for a communications link where a multiwavelength spatial diversity transmitter is used to mitigate ...

Ulmer, Todd G.

84

Amplified spontaneous emission from opal photonic crystals engineered with structural defectsw  

E-print Network

Amplified spontaneous emission from opal photonic crystals engineered with structural defectsw opals engineered with planar structural defects containing a conjugated polymer emitter. Defects in opals give rise to allowed states inside the photonic stop band, which are probed by transmittance

85

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

SciTech Connect

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

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

2012-08-31

86

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...

87

IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 31, NO. 2, FEBRUARY 1995 399 Spontaneous Emission in Microcavities  

E-print Network

. Using this simplified geometry, we derive an analytic expression for the spontaneous emission rate an analytic approach to spon- taneous emission in resonators with distributed Bragg reflectors (DBR to radiation with both angular and frequency distributions.This has allowed us to derive approximate analytic

York, Robert A.

88

Manipulation of the spontaneous emission in mesoporous synthetic opals impregnated with fluorescent guests.  

PubMed

The spontaneous emission of light from light-emitting materials adsorbed within the ordered pores of monodispersed mesoporous silica spheres (MMSS) has been investigated. By taking advantage of the ordered starburst pores of MMSS, we can provide a simple strategy for fabricating synthetic opals consisting of homogeneous individual building blocks in which fluorescent guests are uniformly and stably impregnated. In this study, tris(8-hydroxyquinolinato)aluminum(III) (Alq(3)) and Rhodamine B (Rh B) are selected as the fluorescent guests. The former has a wider emission band than the reflection spectrum of MMSS synthetic opals, whereas the emission band of the latter is considerably narrower than the reflection spectrum of the opals. The spontaneous emissions of these functionalized synthetic opals are clearly influenced by the stop band governed by the Bragg equation. In the case of the Alq(3)-MMSS conjugate, the shape of the Alq(3) emission spectrum varies in accordance with the shift in the stop band. The emission of the Rh B-MMSS conjugate is noticeably narrowed, and its intensity is enhanced when the excitation intensity is increased. These results are well explained by an inhibition of spontaneous emission caused by a reduction in the density of optical states within the stop band. The results of this study indicate that MMSS synthetic opals are promising for use in novel optical applications in which the spontaneous emission can be manipulated. PMID:19642624

Yamada, Yuri; Yamada, Hisashi; Nakamura, Tadashi; Yano, Kazuhisa

2009-12-01

89

Modification of spontaneous emission in Bragg onion resonators  

E-print Network

cladding layers, the index contrast of the Bragg cladding, and the refractive index of surrounding medium. Y. Yamamoto, S. Machida and G. Bjork, "Microcavity Semiconductor-Laser with Enhanced Spontaneous. Yang, "Ultralow Threshold Current Vertical-Cavity Surface-Emitting Lasers with Alas Oxide

Huang, Yanyi

90

Amplified spontaneous emission from opal photonic crystals engineered with structural defects.  

PubMed

In this work, we report on the optical properties and amplified spontaneous emissions (ASE) of polystyrene opals engineered with planar structural defects containing a conjugated polymer emitter. Defects in opals give rise to allowed states inside the photonic stop band, which are probed by transmittance and reflectance spectroscopy. The emission spectrum of the polymer embedded in the defect layer is strongly modified and fingerprints of defect states located inside the stop band are recognized. Amplified spontaneous emission for these engineered photonic crystals is clearly observed. PMID:20024423

Di Stasio, Francesco; Berti, Luca; Burger, Martin; Marabelli, Franco; Gardin, Samuele; Dainese, Tiziano; Signorini, Raffaella; Bozio, Renato; Comoretto, Davide

2009-12-28

91

Spontaneous emission of electromagnetic radiation in turbulent plasmas  

SciTech Connect

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.

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

92

Control of Emissions  

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

93

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

PubMed Central

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

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

2014-01-01

94

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

95

Overcoming Auger recombination in nanocrystal quantum dot laser using spontaneous emission enhancement.  

PubMed

We propose a method to overcome Auger recombination in nanocrystal quantum dot lasers using cavity-enhanced spontaneous emission. We derive a numerical model for a laser composed of nanocrystal quantum dots coupled to optical nanocavities with small mode-volume. Using this model, we demonstrate that spontaneous emission enhancement of the biexciton transition lowers the lasing threshold by reducing the effect of Auger recombination. We analyze a photonic crystal nanobeam cavity laser as a realistic device structure that implements the proposed approach. PMID:24663592

Gupta, Shilpi; Waks, Edo

2014-02-10

96

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

SciTech Connect

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

Perera, Chamanei S., E-mail: cp.hettiarachchige@qut.edu.au; Vernon, Kristy C.; Mcleod, Angus [Plasmonic Device Group, Queensland University of Technology, GPO box 2434, Brisbane, Queensland (Australia)

2014-02-07

97

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

SciTech Connect

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.

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

2011-11-15

98

Interactions between Hair Cells Shape Spontaneous Otoacoustic Emissions in a Model of the Tokay Gecko's Cochlea  

PubMed Central

Background The hearing of tetrapods including humans is enhanced by an active process that amplifies the mechanical inputs associated with sound, sharpens frequency selectivity, and compresses the range of responsiveness. The most striking manifestation of the active process is spontaneous otoacoustic emission, the unprovoked emergence of sound from an ear. Hair cells, the sensory receptors of the inner ear, are known to provide the energy for such emissions; it is unclear, though, how ensembles of such cells collude to power observable emissions. Methodology and Principal Findings We have measured and modeled spontaneous otoacoustic emissions from the ear of the tokay gecko, a convenient experimental subject that produces robust emissions. Using a van der Pol formulation to represent each cluster of hair cells within a tonotopic array, we have examined the factors that influence the cooperative interaction between oscillators. Conclusions and Significance A model that includes viscous interactions between adjacent hair cells fails to produce emissions similar to those observed experimentally. In contrast, elastic coupling yields realistic results, especially if the oscillators near the ends of the array are weakened so as to minimize boundary effects. Introducing stochastic irregularity in the strength of oscillators stabilizes peaks in the spectrum of modeled emissions, further increasing the similarity to the responses of actual ears. Finally, and again in agreement with experimental findings, the inclusion of a pure-tone external stimulus repels the spectral peaks of spontaneous emissions. Our results suggest that elastic coupling between oscillators of slightly differing strength explains several properties of the spontaneous otoacoustic emissions in the gecko. PMID:20559557

Gelfand, Michael; Piro, Oreste; Magnasco, Marcelo O.; Hudspeth, A. J.

2010-01-01

99

Spontaneous emission interference enhancement with a ?-negative metamaterial slab  

NASA Astrophysics Data System (ADS)

The spontaneous decay and quantum interference of a V-type Zeeman atom placed near a ?-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.

Zeng, Xiaodong; Xu, Jingping; Yang, Yaping

2011-09-01

100

Electrically Controllable Spontaneous Magnetism in Nanoscale Mixed Phase Multiferroics  

SciTech Connect

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.

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

101

Spontaneous Incidence of Oncocytic Proliferative Lesions in Control Rat Kidney.  

PubMed

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

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

2014-03-20

102

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

PubMed Central

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

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

2014-01-01

103

Thermalization of strongly interacting bosons after spontaneous emissions in optical lattices  

E-print Network

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.

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

2014-08-05

104

Enhanced Spontaneous Emission by Quantum Boxes in a Monolithic Optical Microcavity  

Microsoft Academic Search

Semiconductor quantum boxes (QB's) are well suited to cavity quantum electrodynamic experiments in the solid state because of their sharp emission. We study by time-resolved photoluminescence InAs QB's placed in the core of small-volume and high-finesse GaAs\\/AlAs pillar microresonators. A spontaneous emission rate enhancement by a factor of up to 5 is selectively observed for the QB's which are on

J. M. Gérard; B. Sermage; B. Gayral; B. Legrand; E. Costard; V. Thierry-Mieg

1998-01-01

105

Spontaneous emission rates of dipoles in photonic crystal membranes  

E-print Network

in semiconductor membranes strongly modify the radiative decay of dipole emitters. Three-dimensional finite-difference time-domain calculations show over 7 times inhibition and 15 times enhancement of the emission rate As first proposed by Bykov13 and Yablonovitch,14 three-dimensionally periodic arrangements of dielectric

Soukoulis, Costas

106

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

PubMed

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

de Mello Gallep, Cristiano

2014-12-01

107

Plasmonic engineering of spontaneous emission from silicon nanocrystals  

PubMed Central

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

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

2013-01-01

108

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

SciTech Connect

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.

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

109

Enhancing spontaneous emission rates of molecules using nanopatterned multilayer hyperbolic metamaterials  

NASA Astrophysics Data System (ADS)

Plasmonic nanostructures have been extensively used to manipulate the spontaneous light emission rate of molecules and their radiative efficiency. Because molecules near a metallic surface experience a different environment than in free space, their spontaneous radiative emission rate is generally enhanced. Such enhancement, measured by means of the Purcell factor, arises as a consequence of the overlap between the surface plasmon mode frequency and the emission spectrum of the molecule. However, such overlap is available only for a few narrow bands of frequency due to the limited plasmonic materials existing in nature. Although this limitation can be overcome by using hyperbolic metamaterials (HMMs)--a type of nanoscale artificial material with hyperbolic dispersion relations--the Purcell factor and the radiative power have remained relatively low. Here, we show that by nanopatterning a hyperbolic metamaterial made of Ag and Si multilayers, the spontaneous emission rate of rhodamine dye molecules is enhanced 76-fold at tunable frequencies and the emission intensity of the dye increases by ~80-fold compared with the same hyperbolic metamaterial without nanostructuring. We explain these results using a dynamic Lorentzian model in the time domain.

Lu, Dylan; Kan, Jimmy J.; Fullerton, Eric E.; Liu, Zhaowei

2014-01-01

110

Amplified spontaneous emission of glass forming DCM derivatives in PMMA films  

NASA Astrophysics Data System (ADS)

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.

Vembris, Aivars; Zarinsh, Elmars; Kokars, Valdis

2014-05-01

111

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

E-print Network

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... Station, Texas 77843, USA #1;Received 28 April 2009; published 3 August 2009#2; The spontaneous decay of a multilevel atom interacting with the electromagnetic field in free space is investigated with a unitary transformation method, which is introduced...

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

2009-01-01

112

Endocrine disruptors and spontaneous premature labor: a case control study  

PubMed Central

Background Premature labor is a poorly understood condition. Estrogen is thought to play a key role and therefore the labor process may be affected by endocrine disruptors. We sought to determine whether or not an environmental toxicant, DDE, or dietary derived endocrine disruptors, daidzein and genistein, are associated with spontaneous preterm labor. Methods Cases were defined as primiparous patients having a preterm delivery at or before 35 weeks following the spontaneous onset of labor. Controls were defined as primiparous women who delivered on the same day as the cases but at term gestation. Over approximately 1 year, 26 cases and 52 controls were recruited. Subjects agreed to have blood tests on day one postpartum for DDE and for the phytoestrogens genistein and daidzein. Results The mean concentration of DDE was similar in the case and control groups: 4.29 vs 4.32 ng/g lipid p = .85. In the case group, 13/26 had detectable levels of daidzein (range 0.20 – 1.56 ng/ml) compared to 25/52 controls (range 0.21 – 3.26 ng/ml). The mean concentration of daidzein was similar in cases compared to controls: 0.30 vs .34 ng/ml p = 0.91. Of the case group,14/26 had detectable levels of genistein (range 0.20 – 2.19 ng/ml) compared to 32/52 controls (range 0.21 – 2.55 ng/ml). The mean concentration of genistein was similar in cases compared to controls: 0.39 vs 0.31 ng/ml, p = 0.61. Conclusion The serum levels of DDE in this population were found to be low. There appears to be no relationship between serum concentrations of DDE, daidzein, and genistein and spontaneous preterm labor in our population. The inability to identify an effect may be related to the comparatively low concentrations of DDE in our population and the rapid and variable reduction of phytoestrogens from women in labor. PMID:18005447

Wood, Stephen L; Jarrell, John J; Swaby, Cheryl; Chan, Sui

2007-01-01

113

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

PubMed Central

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

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

2014-01-01

114

Emission control system  

NASA Technical Reports Server (NTRS)

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.

Parrish, Clyde F. (Inventor)

2008-01-01

115

Advanced Emissions Control Development Program  

SciTech Connect

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).

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

1998-04-01

116

Experimental demonstration of enhanced self-amplified spontaneous emission by an optical klystron.  

PubMed

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. PMID:25615469

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

2015-01-01

117

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

118

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

SciTech Connect

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.

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

119

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

SciTech Connect

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.

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

120

Advanced Emission Control Development Program.  

SciTech Connect

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.

Evans, A.P.

1997-12-31

121

Localization of Relative-Position of Two Atoms Induced by Spontaneous Emission  

E-print Network

We revisit the back-action of emitted photons on the motion of the relative position of two cold atoms. We show that photon recoil resulting from the spontaneous emission can induce the localization of the relative position of the two atoms through the entanglement between the spatial motion of individual atoms and their emitted photons. The result provides a more realistic model for the analysis of the environment-induced localization of a macroscopic object.

L. Zheng; C. Li; Y. Li; C. P. Sun

2005-01-16

122

Localization of the relative position of two atoms induced by spontaneous emission  

SciTech Connect

We reexamine the back-action of emitted photons on the wave packet evolution about the relative position of two cold atoms. We show that photon recoil resulting from the spontaneous emission can induce the localization of the relative position of the two atoms through the entanglement between the spatial motion of individual atoms and their emitted photons. The obtained result provides a more realistic model for the analysis of the environment-induced localization of a macroscopic object.

Zheng, L. [Center of Theoretical Physics, Jilin University, Changchun, 130023 (China) and Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, 100080 (China); Li, C.; Li, Y.; Sun, C.P. [Institute of Theoretical Physics, The Chinese Academy of Science, Beijing, 100080 (China)

2005-06-15

123

Spontaneous Emission Lifetime of a Single Trapped Ca+ Ion in a High Finesse Cavity  

Microsoft Academic Search

We investigate the spontaneous emission lifetime of a single trapped 40Ca+ ion placed at different positions in the vacuum standing wave inside a high finesse cavity which is stabilized to the atomic transition. The lifetime is measured by quantum state detection after pi-pulse excitation. The result for the natural lifetime of the D5\\/2 metastable state of 1161(22)ms agrees, within 1

A. Kreuter; C. Becher; G. P. Lancaster; A. B. Mundt; C. Russo; H. Häffner; C. Roos; J. Eschner; F. Schmidt-Kaler; R. Blatt

2004-01-01

124

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

Microsoft Academic Search

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

Emmanuel Desurvire; JAY R. SIMPSON

1989-01-01

125

High-power near-diffraction-limited solid-state amplified spontaneous emission laser devices  

Microsoft Academic Search

We present investigations into high-power scaling of solid-state amplified spontaneous emission (ASE) laser sources by use of two high-gain (˜104) Nd:YVO4 bounce amplifiers. The sources deliver high power with a high-quality spatial output, but unlike a laser they have a high misalignment tolerance and do not require a precisely aligned cavity. In one system with two amplifiers, we demonstrate an

G. Smith; P. C. Shardlow; M. J. Damzen

2007-01-01

126

Spatially-selective amplified spontaneous emission source derived from an ultrahigh gain solid-state amplifier  

Microsoft Academic Search

An investigation is made into the performance of a high power solid-state amplified spontaneous emission (ASE) source with near-diffraction-limited beam quality. The radiation from this ASE source has high spatial quality and power, but unlike a laser it has a high misalignment tolerance and does not require a precisely aligned cavity. The source is based on a diode-pumped Nd:YVO4 laser

G. Smith; M. J. Damzen

2006-01-01

127

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

128

Polarization and Angle Dependent Spontaneous Emission Rates in Hybrid Metal-Semiconductor Nanostructures  

NASA Astrophysics Data System (ADS)

Recently, the coupling of a dipole emitter to surface plasmons (SPs) of metal nanostructures has attracted much attention for its potential applications in light emitting devices. Our time-resolved photoluminescence (PL) study on the emission of CdSe/ZnS core/shell nanocrystals (NCs) deposited on a two-dimensional array of gold nanodiscs demonstrates that the spontaneous emission of dipole emitters is strongly dependent on the detection angles and polarizations. The in-plane, s-polarized PL measurements are independent on detection angles, and can be described by the PL decay dynamics of two NC subsets: the emission from NCs on the dielectric substrate and from NCs on the gold nanodiscs that experience non-radiative quenching by the metal structures. The out-of-plane, p-polarized PL measurements show an additional decay caused by SP-induced enhancement of the spontaneous emission rate. This angular-dependent enhancement is explained by interactions between NC dipole moments and the out-of-plane SP resonance of the gold nanodiscs.

Wang, Yikuan; Yang, Tianyu; Tuominen, Mark; Achermann, Marc

2009-03-01

129

Quantum interference in spontaneous emission from a V-type three-level atom in photonic crystals  

E-print Network

Studying the spontaneous emission of a V-type three-level atom embedded in a photonic crystal (PC) by fractional calculus, we found that the atomic excited states in the anisotropic PC can be expressed as a superposition of four dressed states analytically. Through detuning two allowed atomic transition energies with respect to the photonic band edge, the coupling between these two transitions leads to three dynamic regimes, namely non-Markovian decay, damped quantum interference and quantum interference, classified by the numbers of contributed bounded dressed states. From the degree of quantum interference of two atomic transitions, we found the energy exchange between the atom and PC reservoir is the lowest as the excited states become degenerate but with maximum quantum interference when the atom is prepared at one of the excited states. The results also show that excited states prefer to stay out of phase at all detuning energy except for near degenerate. Therefore, we can control the spontaneous emission rate not only by the amount of detuning frequencies but also the relative phase of initial states.

Chih-Hsien Huang Jing-Nuo Wu; Yen-Yin Li; Szu-Cheng Cheng; Wen-Feng Hsieh

2011-01-25

130

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

PubMed

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

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

2015-01-28

131

Polarization and Angle Dependent Spontaneous Emission Rates in Hybrid Metal-Semiconductor Nanostructures  

NASA Astrophysics Data System (ADS)

We are interested in exciton-plasmon interactions between semiconductor nanocrystals (NCs) and a gold nanodisc array. Using angle resolved white-light transmission spectroscopy we identified localized in- and out-of-plane surface plasmon (SP) resonances in the gold array. Upon depositing CdSe/ZnS (core/shell) NCs on the metal disc array, we measured photoluminescence (PL) decay rates of the NCs as a function of emission direction and polarization by time-correlated single photon counting technique. Since the wavelengths of the selected NCs matched the out-of-plane SP resonance wavelengths of gold array, the spontaneous emission of the NCs is strongly dependent on detection angles and polarizations. The in-plane, s-polarized PL measurements are independent on detection angles, and can be described by the PL decay dynamics of two NC subsets: from NCs on the dielectric substrate and from NCs on the gold nanodiscs that experience non-radiative quenching by the metal structures. The out-of-plane, p-polarized PL measurements show an increase of the PL amplitude and an accelerated PL decay, both caused by SP-induced enhancement of the spontaneous emission rate.

Wang, Yikuan; Yang, Tianyu; Tuominen, Mark; Achermann, Marc

2011-04-01

132

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

SciTech Connect

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.

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

133

Electrostatic Control of Spontaneous Vesicle Aggregation Scott A. Walker and Joseph A. Zasadzinski*  

E-print Network

Electrostatic Control of Spontaneous Vesicle Aggregation Scott A. Walker and Joseph A. Zasadzinski of the specific recognition interaction makes controlling aggregation via electrostatics possible. These results also suggest that electrostatic interactions are at least somewhat responsible for the stability

Zasadzinski, Joseph A.

134

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

E-print Network

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

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

2007-01-01

135

Transverse amplified spontaneous emission: The limiting factor for output energy of ultra-high power lasers  

NASA Astrophysics Data System (ADS)

For the new generation of the ultra-high power lasers with tens of PW of output power, kJ-level energies have to be reached. Our modeling, applied to Ti:sapphire amplifiers, demonstrates for the first time, according our knowledge, that Transverse Amplified Spontaneous Emission (TASE) places an additional restriction on storing and extracting energy in larger gain apertures, even stronger than transverse parasitic generation (TPG). Nevertheless, we demonstrate that extracting during pumping (EDP) can significantly reduce parasitic losses due to both TASE and TPG.

Chvykov, Vladimir; Nees, John; Krushelnick, Karl

2014-02-01

136

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

USGS Publications Warehouse

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.

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

2008-01-01

137

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

E-print Network

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.

Anil K. Patnaik; G. S. Agarwal

1998-10-16

138

Amplified spontaneous emission of Rhodamine 6G embedded in pure deoxyribonucleic acid  

NASA Astrophysics Data System (ADS)

Deoxyribonucleic acid (DNA) is commonly viewed as a genetic information carrier. However, now it is recognized as a nanomaterial, rather than as a biological material, in the research field of nanotechnology. Here, we show that using pure DNA, doped with rhodamine 6G, we are able to observe amplified spontaneous emission (ASE) phenomenon. Moderate ASE threshold, photodegradation, and reasonable gain coefficient observed in this natural host gives some perspectives for practical applications of this system in biophotonics. Obtained results open the way and will be leading to construction of truly bio-lasers using nature made luminophores, such as anthocyanins.

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

2012-10-01

139

Amplified spontaneous emission and pulse train amplification in a KrF amplifier  

SciTech Connect

We present modeling status of pulse-train amplification experiments conducted at Sandia National Laboratory in Albuquerque (SNLA) with an e-beam pumped KrF laser amplifier. The laser geometry is such that the dominant amplified spontaneous emission (ASE) growth is along the propagation axis. Our numerical studies include the propagation of on axis co- and counter-propagating fields for both the pulse train and ASE simultaneously. The time-dependent gain, absorption, formation and quenching rates are obtained from a state-of-the-art kinetics code developed at Los Alamos National Laboratory (LANL). 12 refs., 12 figs.

Ackerhalt, J.R.; Hanson, D.E.; Adams, R.G.; Raymond, T.D.; Reiser, C.; Rice, J.K.; Michie, R.B.

1988-01-01

140

Amplified spontaneous emission and lasing properties of bisfluorene-cored dendrimers  

NASA Astrophysics Data System (ADS)

A study of the amplified spontaneous emission (ASE) properties of three bisfluorene-cored dendrimers in the solid state is reported. The results show that the dendron type has a strong impact on the photoluminescence quantum yield and affects the ASE threshold, the optical gain, and loss coefficients. Optically pumped distributed feedback lasers operating in the blue spectral region were fabricated by spin coating the dendrimer films on top of a two-dimensional corrugated fused silica substrate. A best lasing threshold of 4.5?J/cm2 and a slope efficiency of 8.3% were obtained, which demonstrate the high potential of these materials for laser applications.

Ribierre, J. C.; Tsiminis, G.; Richardson, S.; Turnbull, G. A.; Samuel, I. D. W.; Barcena, H. S.; Burn, P. L.

2007-08-01

141

Measurement of gain characteristics of semiconductor lasers by amplified spontaneous emissions from dual facets.  

PubMed

In this letter, we describe a novel gain measurement approach for semiconductor edge-emitting lasers, with which TE and TM gain spectra can be easily obtained by collecting the amplified spontaneous emissions at dual facets of the device. An unstrained and continuously-operated GaAs/AlGaAs single quantum well laser strip is used to illustrate this method. The measured gain spectra are compared with theoretical gain curves to analyze the gain polarization characteristics and the relevant subband structure in the valence band of the well using the measured gain spectra. PMID:23609743

Ma, M-L; Wu, J; Ning, Y-Q; Zhou, F; Yang, M; Zhang, X; Zhang, J; Shang, G-Y

2013-04-22

142

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

PubMed

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

Deng, Lier; Wang, Yongsheng; He, Dawei

2011-11-01

143

arXiv:cond-mat/0512120v16Dec2005 Spontaneous emission rates of dipoles in photonic crystal membranes  

E-print Network

the spontaneous emission rate of embedded dipole emitters. Three-dimensional Finite- Difference Time that finite two-dimensional (2D) photonic crystals in thin semiconductor membranes strongly modify-Domain calculations show over 7 times inhibition and 15 times enhancement of the emission rate compared to the vacuum

144

Dynamics of spontaneous emission in a single-end photonic waveguide  

NASA Astrophysics Data System (ADS)

We investigate the spontaneous emission of a two-level system, e.g., an atom or atomlike object, coupled to a single-end, i.e., a semi-infinite, one-dimensional photonic waveguide such that one end behaves as a perfect mirror while light can pass through the opposite end with no backreflection. Through a quantum microscopic model we show that such geometry can cause nonexponential and long-lived atomic decay. Under suitable conditions, a bound atom-photon stationary state appears in the atom-mirror interspace so as to trap a considerable amount of initial atomic excitation. Yet this can be released by applying an atomic frequency shift, causing a revival of photon emission. The resilience of such effects to typical detrimental factors is analyzed.

Tufarelli, Tommaso; Ciccarello, Francesco; Kim, M. S.

2013-01-01

145

Amplified spontaneous emission (ASE) models and approximations for thin-disk laser modeling  

NASA Astrophysics Data System (ADS)

It is well-known that amplified spontaneous emission (ASE) can be a major source of upper laser level loss in high gain pulsed or steady-state solid state lasers. This paper briefly reviews the theory of ASE and, using a simple rate equation model of the upper laser level, a geometric, radiative transport equation to describe the ASE intensity, and the perturbation method of multiple time scales, demonstrates that the loss rate of the upper laser level due to ASE adiabatically follows the spontaneous emission source term. This result which includes gain saturation is applicable to both quasi-three level and four level lasers and rigorously justifies formally using the steady-state expression derived heuristically by Lowenthal and Eggleston1 to model ASE loss in pulsed laser media. Then, it is shown that the frequency integral occurring in the ASE loss term can be evaluated analytically for both a broad "flat-top" and a Lorentzian stimulated emission lineshape but must be evaluated numerically or using an approximation due to Tommasini and Balmer2 for a Gaussian stimulated emission lineshape. It is shown that at high gain loss due to ASE is mitigated by ASE line narrowing. For a thin disk laser an approximate expression for the rate of ASE loss (or ASE lifetime) can be obtained by evaluating the remaining volume integral using either the method of Speiser3 or of Vretenar et al4. A new approximate expression for the ASE loss rate is obtained which, unlike Speiser's3 expression, accounts for ASE line narrowing and, unlike Vretenar et al's4 expression, correctly scales with the cylindrical volume of the disk. Application to both 1D and 3D laser modeling is briefly discussed.

Copeland, Drew A.

2013-03-01

146

On the spontaneous emission of electromagnetic radiation in the CSL model  

SciTech Connect

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.

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

147

Madey's theorems for free-electron devices, spontaneous emission, and applications  

NASA Astrophysics Data System (ADS)

Two theorems due to Madey occupy a central position in free-electron laser physics: one relates the gain to the derivative of the spontaneous emission line shape and the other one relates it to the derivative of the electron energy spread in stimulated emission. We use quantum mechanical perturbation thoery of first order in the radiation field to give a general derivation of the theorems based on (a) the hermiticity of the electronfield interaction, (b) the applicability of lowest order perturbation theory, and (c) the assumption that the emitted photon have a sufficiently low energy. Assumption (b) restricts the validity of the theorems to the small-signal weak-field regime, (c) to the small recoil regime where the gain is classical. We use scalar quantum electrodynamics in the Furry picture in order to keep effects which are nonlinear in the undulator field, e.g. higher harmonic emission. We consider a fairly general one-dimensional (i.e. not having transverse variations) monochromatic undulator field (magnetic or optical undulator, linear or circular polarization, possible presence of a diffractive medium). An appendix considers nonmonochromatic fields. We derive explicit results for the linearly polarized and the helical undulator allowing for an arbitrary orientation of the undulator axis, the electron beam and the emitted radiation with respect to each other. In particular, we discuss the case of Gaussian modes where the applicability of the first theorem has been questioned. It turns out that the theorem is applicable provided that spontaneous emission into the Gaussian mode in question is considered (more generally, into whatever mode is of interest for the gain).

Becker, W.; McIver, J. K.

1988-12-01

148

On the spontaneous emission of electromagnetic radiation in the CSL model  

E-print Network

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.

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

2013-07-03

149

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

PubMed

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

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

2014-05-19

150

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

PubMed

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

Pinhasi, Y; Lurie, Yu

2002-02-01

151

Nonlinear resonance: Determining maximal autoresonant response and modulation of spontaneous otoacoustic emissions  

NASA Astrophysics Data System (ADS)

Sustained resonance in a linear oscillator is achievable with a drive whose constant frequency matches the resonant frequency of the oscillator. In oscillators with nonlinear restoring forces, i.e., Duffing-type oscillators, resonant frequency changes with amplitude, so a constant frequency drive generates a beat oscillation instead of sustained resonance. Duffing-type oscillators can be driven into sustained resonance, called autoresonance (AR), when drive frequency is swept in time to match the changing resonant frequency of the oscillator. It is found that near-optimal drive linear sweep rates for autoresonance can be estimated from the beat oscillation resulting from constant frequency excitation. Specifically, a least squares estimate of the slope of the Teager-Kaiser instantaneous frequency versus time plot for the rising half-cycle of the beat response to a stationary drive provides a near-optimal estimate of the linear drive sweep rate that sustains resonance in the pendulum, Duffing and Duffing-Van der Pol oscillators. These predictions are confirmed with model-based numerical simulations. A closed-form approximation to the AM-FM nonlinear resonance beat response of a Duffing oscillator driven at its low-amplitude oscillator frequency is obtained from a solution to an associated Mathieu equation. AR time responses are found to evolve along a Mathieu equation primary resonance stability boundary. AR breakdown occurs at sweep rates just past optimal and map to a single stable point just off the Mathieu equation primary resonance stability boundary. Optimal AR sweep rates produce oscillating phase differences with extrema near 90 degrees, allowing extended time in resonance. AR breakdown occurs when phase difference equals 180 degrees. Nonlinear resonance of the van der Pol type may play a role in the extraordinary sensitivity of the human ear. The mechanism for maintaining the cochlear amplifier at its critical point is currently unknown. The possibility of open-loop control of cochlear operating point, maintaining criticality on average through periodically varying damping (super-regeneration) motivates a study of spontaneous otoacoustic emission (SOAE) amplitude modulation on a short (msec) time scale. An example of periodic amplitude modulation within a wide filter bandwidth is found that appears to be a beat oscillation of two SOAEs.

Witkov, Carey

2011-12-01

152

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

SciTech Connect

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.

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

153

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...

154

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

155

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

PubMed

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

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

2014-01-13

156

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 ...

157

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

158

Observation of self-amplified spontaneous emission in the near-infrared and visible wavelengths M. Babzien,1  

E-print Network

Observation of self-amplified spontaneous emission in the near-infrared and visible wavelengths M cutoff characteristic of wake fields , and beam plasma frequency is not great. In far infrared wavelength by several groups 9,10 working in the far-infrared region. These experiments, therefore, cannot study

Wurtele, Jonathan

159

The effect of amplified spontaneous emission on the measurement of the multiplet state distribution of ground state oxygen atoms  

NASA Astrophysics Data System (ADS)

Experiments are conducted to verify the existence of amplified spontaneous emission (ASE) in ground state O atoms, and a kinetic model is developed to confirm the results. Both ASE and laser-induced fluorescence are observed at 845 nm, and the distributions observed at 845 are distorted by ASE. The atomic populations are depleted selectively from the original multiplet levels.

Huang, Yu-Lin; Gordon, Robert J.

1992-11-01

160

Observation and analysis of self-amplified spontaneous emission at the APS low-energy undulator test line  

Microsoft Academic Search

Exponential growth of self-amplified spontaneous emission at 530nm was first experimentally observed at the Advanced Photon Source low-energy undulator test line in December 1999. Since then, further detailed measurements and analysis of the results have been made. Here, we present the measurements and compare these with calculations based on measured electron beam properties and theoretical expectations.

N. D. Arnold; J. Attig; G. Banks; R. Bechtold; K. Beczek; C. Benson; S. Berg; W. Berg; S. G Biedron; J. A Biggs; M. Borland; K. Boerste; M. Bosek; W. R Brzowski; J. Budz; J. A Carwardine; P. Castro; Y.-C Chae; S. Christensen; C. Clark; M. Conde; E. A Crosbie; G. A Decker; R. J Dejus; H. DeLeon; P. K Den Hartog; B. N Deriy; D. Dohan; P. Dombrowski; D. Donkers; C. L Doose; R. J Dortwegt; G. A Edwards; Y. Eidelman; M. J Erdmann; J. Error; R. Ferry; J. Forrestal; H. Freund; H. Friedsam; J. Gagliano; W. Gai; J. N Galayda; R. Gerig; R. L Gilmore; E. Gluskin; G. A Goeppner; J. Goetzen; C. Gold; A. J Gorski; A. E Grelick; M. W Hahne; S. Hanuska; K. C Harkay; G. Harris; A. L Hillman; R. Hogrefe; J. Hoyt; Z. Huang; J. M Jagger; W. G Jansma; M. Jaski; S. J Jones; R. T Keane; A. L Kelly; C. Keyser; K.-J Kim; S. H Kim; M. Kirshenbaum; J. H Klick; K. Knoerzer; R. J Koldenhoven; M. Knott; S. Labuda; R. Laird; J. Lang; F. Lenkszus; E. S Lessner; J. W Lewellen; Y. Li; R. M Lill; A. H Lumpkin; O. A Makarov; G. M Markovich; M. McDowell; W. P McDowell; P. E McNamara; T. Meier; D. Meyer; W. Michalek; S. V. Milton; H. Moe; E. R Moog; L. Morrison; A. Nassiri; J. R Noonan; R. Otto; J. Pace; S. J Pasky; J. M Penicka; A. F Pietryla; G. Pile; C. Pitts; J. Power; T. Powers; C. C. Putnam; A. J Puttkammer; D. Reigle; L. Reigle; D. Ronzhin; E. R Rotela; E. F Russell; V. Sajaev; S. Sarkar; J. C Scapino; K. Schroeder; R. A Seglem; N. S Sereno; S. K Sharma; J. F Sidarous; O. Singh; T. L Smith; R. Soliday; G. A Sprau; S. J Stein; B. Stejskal; V. Svirtun; L. C Teng; E. Theres; K. Thompson; B. J Tieman; J. A Torres; E. M Trakhtenberg; G. Travish; G. F Trento; J. Vacca; I. B Vasserman; N. A Vinokurov; D. R Walters; J. Wang; X. J Wang; J. Warren; S. Wesling; D. L Weyer; G. Wiemerslage; K. Wilhelmi; R. Wright; D. Wyncott; S. Xu; B.-X. Yang; W. Yoder; R. B Zabel

2001-01-01

161

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...

162

Spatially-selective amplified spontaneous emission (ASE) sources derived from a high-gain solid-state amplifier  

Microsoft Academic Search

We present high power amplified spontaneous emission sources with spatial selectivity, based on an ultra-high gain diode-pumped Nd:YVO4 crystal in a bounce amplifier geometry. Output power 30 W was achieved with near diffraction-limited spatial quality.

G. Smith; M. J. Damzen

2006-01-01

163

ASSESSMENT OF THE CONTROLLABILITY OF CONDENSIBLE EMISSIONS  

EPA Science Inventory

The report gives results of a study to gain insights into the condensible emissions area from an air toxics perspective, with emphasis on controllability and chemical composition of these emissions. he study compiled existing data on condensible emissions; determined the chemical...

164

Cortical muscle control of spontaneous movements in human neonates.  

PubMed

Anatomical studies show the existence of corticomotor neuronal projections to the spinal cord before birth, but whether the primary motor cortex drives muscle activity in neonatal 'spontaneous' movements is unclear. To investigate this issue, we calculated corticomuscular coherence (CMC) and Granger causality in human neonates. CMC is widely used as an index of functional connectivity between the primary motor cortex and limb muscles, and Granger causality is used across many fields of science to detect the direction of coherence. To calculate CMC and Granger causality, we used electroencephalography (EEG) to measure activity over the cortical region that governs leg muscles, and surface electromyography (EMG) over the right and left tibialis anterior muscles, in 15 healthy term and preterm neonates, during spontaneous movements without any external stimulation. We found that 17 leg muscles (10 right, seven left) in 12 neonates showed significant CMC, whose magnitude significantly correlated with postnatal age only in the beta frequency band. Further analysis revealed Granger causal drive from EEG to EMG in 14 leg muscles. Our findings suggest that the primary motor cortex drives muscle activity when neonates move their limbs. Moreover, the positive correlation between CMC magnitude and postnatal age suggests that corticomuscular communication begins to develop during the neonatal stage. This process may facilitate sensory-motor integration and activity-dependent development. PMID:24827432

Kanazawa, Hoshinori; Kawai, Masahiko; Kinai, Takahiro; Iwanaga, Kougorou; Mima, Tatsuya; Heike, Toshio

2014-08-01

165

Realization of dynamic thermal emission control.  

PubMed

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

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

2014-10-01

166

Realization of dynamic thermal emission control  

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

167

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

PubMed Central

?-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

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

2014-01-01

168

Coherent coupling and modified spontaneous emission of a single ion in a high finesse optical cavity  

NASA Astrophysics Data System (ADS)

thanksIn collaboration with A. Kreuter, A.B. Mundt, C. Russo, H. Häffner, C. Roos, J. Eschner, F. Schmidt-Kaler and R. Blatt, Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria. Laser-cooled trapped atoms or ions are ideally suited systems for storing and processing quantum information. The transport of this quantum information over large distances via photons requires an interface between atoms and photons (J.I. Cirac et al., Phys. Rev. Lett. 78, 3221 (1997)). Such an interface is based on the deterministic coherent coupling of a single atom or ion to macroscopic and vacuum fields inside a high finesse optical cavity. Here, we perform two experiments to investigate such an interaction of a single Ca^+ ion and a cavity field: first, we excite Rabi oscillations with short resonant laser pulses injected into the cavity, and second, we measure the modification of the spontaneous emission rate from the metastable D_5/2 level induced by the cavity-enhanced vacuum field. The ^40Ca^+ ion is stored in a spherical Paul trap placed in the center of a high finesse near-confocal resonator (Finesse approx. 30.000 at 729 nm). The ion is laser-cooled to the Lamb-Dicke regime, confining its spatial wave packet to a region much smaller than the optical wavelength. We stabilize the cavity to the S_1/2 - D_5/2 quadrupole transition frequency (wavelength: 729 nm) using a transfer lock technique (A.B. Mundt et al., Appl. Phys. B, in press). To demonstrate coherent coupling of the ion and a macroscopic cavity field, we inject resonant laser pulses of different pulse lengths at 729 nm into the cavity and record the excitation on the S_1/2 - D_5/2 transition via the electron shelving technique. We observe a Rabi oscillation frequency of up to 9 MHz when the ion is placed in a node of the cavity standing wave field. (Rabioscillations) For the measurement of the cavity modified spontaneous emission (Purcell effect), we repeat the following sequence for 1oo times: first, we excite the ion with a ?-pulse on the S_1/2 - D_5/2 transition. We then detect whether the excitation was successful (electron shelving), wait for a certain delay time and measure the D_5/2 population again. Every second experimental run, we shift the cavity by approx. 5 linewidths away from resonance. By repeating this procedure for many times we infer the spontaneous decay rate from the metastable level for the cavity on resonance and off resonance (equivalent to free space emission), thus excluding systematic errors due to environmental effects. For the free-space lifetime we measure a value of 1129(19) ms, close to the currently most precisely measured value of 1168 ms (P. Barton et al., Phys. Rev. A 62, 032503 (2000)). First experiments with a delay time of 90 ms show a lifetime reduction of approx. 10% on resonance. 78, l. Phys. B, in pr ess.

Becher, Christoph

2003-05-01

169

Brain modularity controls the critical behavior of spontaneous activity  

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

170

Effects of contralateral acoustic stimulation on spontaneous otoacoustic emissions and hearing threshold fine structure.  

PubMed

Medial olivocochlear (MOC) influence on cochlear mechanics can be noninvasively, albeit indirectly, explored via the effects of contralateral acoustic stimulation (CAS) on otoacoustic emissions. CAS-mediated effects are particularly pronounced for spontaneous otoacoustic emissions (SOAEs), which are typically reduced in amplitude and shifted upward in frequency by CAS. We investigated whether similar frequency shifts and magnitude reductions were observed behaviorally in the fine structure of pure-tone hearing thresholds, a phenomenon thought to share a common underlying mechanism with SOAEs. In normal-hearing listeners, fine-resolution thresholds were obtained over a narrow frequency range centered on the frequency of an SOAE, both in the absence and presence of 60-dB SPL broadband CAS. While CAS shifted threshold fine structure patterns and SOAEs upward in frequency by a comparable amount, little reduction in the presence or depth of fine structure was observed at frequencies near those of SOAEs. In fact, CAS typically improved thresholds, particularly at threshold minima, and increased fine structure depth when reductions in the amplitude of the associated SOAE were less than 10 dB. Additional measurements made at frequencies distant from SOAEs, or near SOAEs that were more dramatically reduced in amplitude by the CAS, revealed that CAS tended to elevate thresholds and reduce threshold fine structure depth. The results suggest that threshold fine structure is sensitive to MOC-mediated changes in cochlear gain, but that SOAEs complicate the interpretation of threshold measurements at nearby frequencies, perhaps due to masking or other interference effects. Both threshold fine structure and SOAEs may be significant sources of intersubject and intrasubject variability in psychoacoustic investigations of MOC function. PMID:25245498

Dewey, James B; Lee, Jungmee; Dhar, Sumitrajit

2014-12-01

171

Cold test, spontaneous emission and gain in a rectangular Cerenkov amplifier  

SciTech Connect

The authors present experimental results for the rectangular Cerenkov grating amplifier. This research is being carried out to develop a Ka-band (35 GHz), low voltage (10 kV), moderate power (10 kW) source. They have constructed a Ku-band grating structure to study a scaled version of this source. The tapered grating consists of two tapered Ku-band smooth wave guide sections and two 3.5-inch sections of five-step-tapered gratings. Both tapered and untapered grating structures have been cold tested utilizing the network analyzer measurements. They find that their taper design reduced the reflection coefficient from {minus}5 dB to less than {minus}20 dB over a 12--15 GHz bandwidth. Spontaneous emission results resulting from passing the circular electron beam from a Litton thermionic gun over the grating structure will be presented. They have theoretically investigated the sheet beam interaction with hybrid modes in a deep groove rectangular grating waveguide. A complex dispersion relation, which includes a finite axial energy spread of the beam, describing the interaction has been solved. The authors find that the instability is always convective in the forward wave mode regime.

Scharer, J.E.; Joe, J.; Booske, J.H.; Basten, M.; Kirolous, H. [Univ. of Wisconsin, Madison, WI (United States). Electrical and Computer Engineering Dept.

1994-12-31

172

Advances in engine emissions control technology  

SciTech Connect

This book is composed of papers presented at the Twelfth Annual Energy-Sources Technology Conference and Exhibition. Topics covered include: Emission control technology for stationary natural gas engines; Environmental aspects of coal-fueled diesel engines; and low emission diesel fuel for 1991-1994.

Chrisman, B. Serve, J.V. (Cooper Industries, Ajax-Superior Division (US))

1989-01-01

173

Variable emissivity laser thermal control system  

DOEpatents

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.

Milner, Joseph R. (Livermore, CA)

1994-01-01

174

Effortful control and spontaneous regulation of emotional behavior in children  

E-print Network

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...

Kieras, Jessica E

2013-02-22

175

Spontaneous Centralization of Control in a Network of Company Ownerships  

PubMed Central

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

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

2013-01-01

176

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

177

Economic growth and carbon emission control  

NASA Astrophysics Data System (ADS)

The question about whether environmental improvement is compatible with continued economic growth remains unclear and requires further study in a specific context. This study intends to provide insight on the potential for carbon emissions control in the absence of international agreement, and connect the empirical analysis with theoretical framework. The Chinese electricity generation sector is used as a case study to demonstrate the problem. Both social planner and private problems are examined to derive the conditions that define the optimal level of production and pollution. The private problem will be demonstrated under the emission regulation using an emission tax, an input tax and an abatement subsidy respectively. The social optimal emission flow is imposed into the private problem. To provide tractable analytical results, a Cobb-Douglas type production function is used to describe the joint production process of the desired output and undesired output (i.e., electricity and emissions). A modified Hamiltonian approach is employed to solve the system and the steady state solutions are examined for policy implications. The theoretical analysis suggests that the ratio of emissions to desired output (refer to 'emission factor'), is a function of productive capital and other parameters. The finding of non-constant emission factor shows that reducing emissions without further cutting back the production of desired outputs is feasible under some circumstances. Rather than an ad hoc specification, the optimal conditions derived from our theoretical framework are used to examine the relationship between desired output and emission level. Data comes from the China Statistical Yearbook and China Electric Power Yearbook and provincial information of electricity generation for the year of 1993-2003 are used to estimate the Cobb-Douglas type joint production by the full information maximum likelihood (FIML) method. The empirical analysis shed light on the optimal policies of emissions control required for achieving the social goal in a private context. The results suggest that the efficiency of abatement technology is crucial for the timing of executing the emission tax. And emission tax is preferred to an input tax, as long as the detection of emissions is not costly and abatement technology is efficient. Keywords: Economic growth, Carbon emission, Power generation, Joint production, China

Zhang, Zhenyu

178

Less Costly Catalysts for Controlling Engine Emissions  

SciTech Connect

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.

Parks, II, James E [ORNL

2010-01-01

179

Environmental controls over methanol emission from leaves  

NASA Astrophysics Data System (ADS)

Methanol is found throughout the troposphere, with average concentrations second only to methane among atmospheric hydrocarbons. Proposed global methanol budgets are highly uncertain, but all agree that at least 60% of the total source arises from the terrestrial biosphere and primary emissions from plants. However, the magnitude of these emissions is also highly uncertain, and the environmental factors which control them require further elucidation. Using a temperature-controlled leaf enclosure, we measured methanol emissions from leaves of six plant species by proton transfer reaction mass spectrometry, with simultaneous measurements of leaf evapotranspiration and stomatal conductance. Rates of emission at 30°C varied from 0.2 to 38 ?g g (dry mass)-1 h-1, with higher rates measured on young leaves, consistent with the production of methanol via pectin demethylation in expanding foliage. On average, emissions increased by a factor of 2.3 for each 10°C increase in leaf temperature. At constant temperature, emissions were also correlated with co-varying incident photosynthetic photon flux density and rates of stomatal conductance. The data were analyzed using the emission model developed by Niinemets and Reichstein (2003a, b), with the incorporation of a methanol production term that increased exponentially with temperature. It was concluded that control of emissions, during daytime, was shared by leaf temperature and stomatal conductance, although rates of production may also vary diurnally in response to variations in leaf growth rate in expanding leaves. The model, which generally provided reasonable simulations of the measured data during the day, significantly overestimated emissions on two sets of measurements made through the night, suggesting that production rates of methanol were reduced at night, perhaps because leaf growth was reduced or possibly through a direct effect of light on production. Although the short-term dynamics of methanol emissions can be successfully modeled only if stomatal conductance and compound solubility are taken into account, emissions on longer time scales will be determined by rates of methanol production, controls over which remain to be investigated.

Harley, P.; Greenberg, J.; Niinemets, É.; Guenther, A.

2007-12-01

180

Environmental controls over methanol emission from leaves  

NASA Astrophysics Data System (ADS)

Methanol is found throughout the troposphere, with average concentrations second only to methane among atmospheric hydrocarbons. Proposed global methanol budgets are highly uncertain, but all agree that at least 60% of the total source arises from the terrestrial biosphere and primary emissions from plants. However, the magnitude of these emissions is also highly uncertain, and the environmental factors which control them require further elucidation. Using a temperature-controlled leaf enclosure, we measured methanol emissions from leaves of six plant species by proton transfer reaction mass spectrometry, with simultaneous measurements of leaf evapotranspiration and stomatal conductance. Rates of emission at 30°C varied from 0.3 to 38 ?g g (dry mass)-1 h-1, with higher rates measured on young leaves, consistent with the production of methanol via pectin demethylation in expanding foliage. On average, emissions increased by a factor of 2.4 for each 10°C increase in leaf temperature. At constant temperature, emissions were also correlated with co-varying incident photosynthetic photon flux density and rates of stomatal conductance. The data were analyzed using the emission model developed by Niinemets and Reichstein (2003a, b), with the incorporation of a methanol production term that increased exponentially with temperature. It was concluded that control of emissions, during daytime, was shared by leaf temperature and stomatal conductance, although rates of production may also vary diurnally in response to variations in leaf growth rate in expanding leaves. The model, which generally provided reasonable simulations of the measured data during the day, significantly overestimated emissions on two sets of measurements made through the night, suggesting that production rates of methanol were reduced at night, perhaps because leaf growth was reduced or possibly through a direct effect of light on production. Although the short-term dynamics of methanol emissions can be successfully modeled only if stomatal conductance and compound solubility are taken into account, emissions on longer time scales will be determined by rates of methanol production, controls over which remain to be investigated.

Harley, P.; Greenberg, J.; Niinemets, Ü.; Guenther, A.

2007-08-01

181

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

E-print Network

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.

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

2012-01-01

182

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

NASA Astrophysics Data System (ADS)

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.

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

183

Advanced CIDI Emission Control System Development  

SciTech Connect

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.

Lambert, Christine

2006-05-31

184

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

E-print Network

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

Apkarian, V. Ara

185

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...

186

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...

187

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

188

Efficient directional spontaneous emission from an InGaAs/InP heterostructure with an integral parabolic reflector  

SciTech Connect

In order to increase the radiative efficiency and directivity of spontaneous emission from a lattice-matched InGaAs/InP heterostructure, we have polished the substrate into a parabolic reflector. We combine optical and thermal measurements to obtain the absolute external efficiency over a wide range of carrier densities. Using a simple model, the measurement is used to determine interface, radiative, and Auger recombination rates in the active material. At the optimal density, the quantum efficiency exceeds 60{percent} at room temperature. The divergence of the emitted light is less than 20{degree}. In fact, the beam profile is dominated by a 6{degree} wide lobe that can be swept across the field of emission by changing the excitation position. This suggests a way to create an all-electronic scanned light beam. {copyright} {ital 1998 American Institute of Physics.}

Gfroerer, T.H.; Cornell, E.A. [JILA, National Institute of Standards and Technology and University of Colorado, and Department of Physics, University of Colorado, Boulder, Colorado, 80309-0440 (United States)] [JILA, National Institute of Standards and Technology and University of Colorado, and Department of Physics, University of Colorado, Boulder, Colorado, 80309-0440 (United States); Wanlass, M.W. [National Renewable Energy Laboratory, Golden, Colorado, 80401 (United States)] [National Renewable Energy Laboratory, Golden, Colorado, 80401 (United States)

1998-11-01

189

Controlling air toxics emissions poses challenges  

SciTech Connect

Emissions from power plants can include trace levels of air toxics such as mercury, selenium and arsenic that exist either partially or completely as a vapor in the flue-gas exit discharge. Other heavy metals such as lead and nickel, which are small, hard to collect particulates, also may be included in the discharged flue gas. Industry and government researchers have had limited success in developing methods to control these trace-level emissions. Developing controls for mercury emissions is complicated by the different forms that mercury can take in the flue gas of a power plant. The most common forms of mercury are elemental mercury (Hg{degree}) and mercuric chloride (HgCl{sub 2}). Hg{degree} has a high vapor pressure as compared to HgCl{sub 2} and most of the other trace toxics, and it typically exists as a vapor in the flue gas exiting power plants. Hg{degree} is also relatively insoluble in water. As a vapor, Hg{degree} can pass through the normal emission control devices that are installed on the majority of modern power plants such as electrostatic precipitators (ESP), fabric filters (FF), or wet scrubbers.

Lausman, R.; Lavely, L. [Black and Veatch Engineers (United States)

1997-08-01

190

Study on spontaneous emission in complex multilayered plasmonic system via surface integral equation approach with layered medium Green's function.  

PubMed

A rigorous surface integral equation approach is proposed to study the spontaneous emission of a quantum emitter embedded in a multilayered plasmonic structure with the presence of arbitrarily shaped metallic nanoscatterers. With the aid of the Fermi's golden rule, the spontaneous emission of the emitter can be calculated from the local density of states, which can be further expressed by the imaginary part of the dyadic Green's function of the whole electromagnetic system. To obtain this Green's function numerically, a surface integral equation is established taking into account the scattering from the metallic nanoscatterers. Particularly, the modeling of the planar multilayered structure is simplified by applying the layered medium Green's function to reduce the computational domain and hence the memory requirement. Regarding the evaluation of Sommerfeld integrals in the layered medium Green's function, the discrete complex image method is adopted to accelerate the evaluation process. This work offers an accurate and efficient simulation tool for analyzing complex multilayered plasmonic system, which is commonly encountered in the design of optical elements and devices. PMID:23037073

Chen, Yongpin P; Sha, Wei E I; Choy, Wallace C H; Jiang, Lijun; Chew, Weng Cho

2012-08-27

191

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

SciTech Connect

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.

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

192

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

NASA Astrophysics Data System (ADS)

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.

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

2010-04-01

193

Nonimaging Optical Gain in Luminescent Concentration through Photonic Control of Emission Etendue  

E-print Network

: luminescence, solar concentration, nonimaging optics, microcavity, spontaneous emission, photovoltaics, requires geometric solar concentrators to track the Sun in order to reach high concentration ratio (CR

Rogers, John A.

194

Surface-plasmon-polariton assisted modification of spontaneous emission of colloidal quantum dots in metal nanostructures  

NASA Astrophysics Data System (ADS)

We experimentally demonstrate extraordinary optical transmission (EOT) assisted photoluminescence (PL) of CdSe/CdS colloidal quantum dots (QDs). The quantum dots were encapsulated between a metallic nanostructure and a Bragg reflector to enhance the interaction of spontaneously emitted photons with a resonant electromagnetic surface wave. The measured PL spectrum of the fabricated sample exhibits spectral narrowing and a shift in peak wavelength of 22 nm and 7 nm, respectively. Furthermore, we tested the angular dependence of the signal to confirm the existence of EOT. This demonstration is a critical step towards realizing plasmonic colloidal QD based coherent emitters.

Briscoe, Jayson L.; Jayasundara, Nadeepa; Cho, Sang-Yeon

2013-01-01

195

Model Identification for Optimal Diesel Emissions Control  

SciTech Connect

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.

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

2013-06-20

196

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...

197

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

PubMed

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

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

2014-05-01

198

Amplified spontaneous emission measurement of a line-narrowed, tunable, Ti:Al2O3 amplifier using rubidium absorption  

NASA Technical Reports Server (NTRS)

Amplified spontaneous emission, ASE, generated by a Ti:Al2O3 laser amplifier has been measured as a function of pump energy, and thus gain, using the atomic absorption of rubidium, Rb, gas at 0.780 micron. By tuning the Ti:Al2O3 laser, the Rb cell could selectively absorb the narrow spectral bandwidth laser radiation while transmitting the wide spectral bandwidth ASE. Transmission of laser amplifier pulses through a Rb absorption cell, measured at various temperatures, thus allows the measurement of the weak ASE in the vicinity of the strong laser pulse. A model for the transmission of Rb as a function of temperature and wavelength has been developed. The measured transmissions are in good agreement with the transmission model predictions.

Barnes, James C.; Barnes, Norman P.; Lockard, George E.; Cross, Patricia L.

1989-01-01

199

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

SciTech Connect

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.

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

200

Spontaneous emission in the near field of two-dimensional photonic crystals  

E-print Network

. Our three- dimensional finite-difference time-domain calculations reveal an inhibition of more than finite-difference time-domain method13­15 to calculate the local radiative density of states (LRDOSSpontaneous emission in the near field of two- dimensional photonic crystals A. Femius Koenderink

201

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

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

202

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

PubMed Central

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

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

2014-01-01

203

Spontaneous coherent cyclotron emission from a short laser-kicked electron buncn  

NASA Astrophysics Data System (ADS)

Ponderomotive kicking of an electron bunch by the field of a laser pulse is proposed as a method for generating coherent cyclotron emission. It is shown that the imparted gyro-rotation can provide selective RF generation in an oversized microwave system, which can be rapidly tuned over a broad frequency range. A possible realization of a moderately relativistic source of short sub-millimeter wavelength pulses is studied.

Savilov, A. V.; Jaroszynski, D. A.

2004-08-01

204

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

NASA Astrophysics Data System (ADS)

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.

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

2009-02-01

205

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...

206

VOC Emission Control with the Brayton Cycle Pilot Plant Operations  

E-print Network

VOC EMISSION CONTROL WITH THE BRAYTON CYCLE PILOT PLANT OPERATIONS (Abstract Only) Joseph C. Enneking, NUCON International, Inc., Columbus, OH A mobile pilot plant capable of removing voe emissions from exhaust air streams was cooperatively...

Enneking, J. C.

207

Control of hazardous air emissions from wood-fired boilers  

SciTech Connect

Hazardous air pollutants are generated by the incomplete combustion of fuels. Emissions are reduced by controlling furnace exit temperatures and establishing minimum residence times. Monitoring carbon monoxide (CO) emissions is important since the amount of carbon monoxide emitted represents the degree of complete combustion which in turn represents the amount of hazardous air pollutants being generated. Wisconsin monitored carbon monoxide emissions from six commercial and institutional wood-fired boilers to evaluate emissions and control strategies. The continuous monitoring data indicate frequent, high amplitude variations in emissions from each source. This highlights the need to control operations to reduce variation in emissions. It also demonstrates a problem with carbon monoxide monitoring strategies that rely on periodic sampling, and offers a challenge for developing more representative and useful carbon monoxide monitoring protocols. This paper presents one regulatory strategy that provides an incentive for operators to reduce emission variations and the resulting hazardous emissions.

Fritz, R.A.; Hubbard, A.J. [Bureau of Air Management, Madison, WI (United States)

1994-12-31

208

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

SciTech Connect

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.

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

2009-06-01

209

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

NASA Astrophysics Data System (ADS)

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).

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

2015-01-01

210

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...

211

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

PubMed

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

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

2007-07-15

212

Safety hazards associated with air-emission controls  

Microsoft Academic Search

Air-emission controls have been installed in refineries since 1990 to comply with environmental regulations such as Benzene NESHAP and the Clean Air Act. Companies have experienced incidents associated with these air-emission controls, but the extent of the problem could not be quantified. In this paper, the authors present the results of a survey of the member companies of API's Safety

Henry Ozog; William J. Erny

2000-01-01

213

Emissions control for ground power gas turbines  

NASA Technical Reports Server (NTRS)

The similarities and differences of emissions reduction technology for aircraft and ground power gas turbines is described. The capability of this technology to reduce ground power emissions to meet existing and proposed emissions standards is presented and discussed. Those areas where the developing aircraft gas turbine technology may have direct application to ground power and those areas where the needed technology may be unique to the ground power mission are pointed out. Emissions reduction technology varying from simple combustor modifications to the use of advanced combustor concepts, such as catalysis, is described and discussed.

Rudney, R. A.; Priem, R. J.; Juhasz, A. J.; Anderson, D. N.; Mroz, T. S.; Mularz, E. J.

1977-01-01

214

Single quantum dot spontaneous emission in a finite-size photonic crystal waveguide: proposal for an efficient "on chip" single photon gun.  

PubMed

Spontaneous emission rate enhancements from a single quantum dot embedded in a finite-size, planar photonic-crystal waveguide are investigated. Short waveguide lengths of only 10 to 20 unit cells are found to produce very large Purcell factors associated with a waveguidelike sharp resonance feature in the local density of photon states. Aided by theoretical insight and rigorous computational calculations, we explain the physics behind these remarkable emission enhancements and subsequently propose a "single-photon gun" with on-chip unidirectional collection efficiencies greater than 60% into an output wire waveguide. The advantages over recent proposals for infinitely long photonic-crystal waveguides are highlighted. PMID:18233077

Rao, V S C Manga; Hughes, S

2007-11-01

215

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.  

PubMed

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. PMID:23848702

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

2013-06-01

216

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

PubMed

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

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

1989-04-01

217

Gaseous emissions from plants in controlled environments  

NASA Technical Reports Server (NTRS)

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.

Dubay, Denis T.

1988-01-01

218

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

NASA Astrophysics Data System (ADS)

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

Woodruff, S.; Cohen, B. I.; Hooper, E. B.; Mclean, H. S.; Stallard, B. W.; Hill, D. N.; Holcomb, C. T.; Romero-Talamas, C.; Wood, R. D.; Cone, G.; Sovinec, C. R.

2005-05-01

219

Coal-fueled diesel technology development emissions control  

Microsoft Academic Search

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

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

1994-01-01

220

Women with spontaneous 46,XX primary ovarian insufficiency (hypergonadotropic hypogonadism) have lower perceived social support than control women  

PubMed Central

Objective To test the hypothesis that women with spontaneous primary ovarian insufficiency differ from control women with regard to perceived social support and to investigate the relationship between perceived social support and self-esteem. Design Cross-sectional Setting Mark O. Hatfield Clinical Research Center, National Institutes of Health. Patient(s) Women diagnosed with spontaneous primary ovarian insufficiency (N=154) at a mean age of 27 years and healthy control women (N=63). Intervention(s) Administration of validated self-reporting instruments. Main Outcome Measure(s) Personal Resource Questionnaire-85 (PRQ85), Rosenberg Self-Esteem Scale Result(s) Women with primary ovarian insufficiency had significantly lower scores than controls on the perceived social support scale and the self-esteem scale. The findings remained significant after modeling with multivariate regression for differences in age, marital status, and having children. In patients there was a significant positive correlation between self-esteem scores and perceived social support. We found no significant differences in perceived social support or self-esteem related to marital status, whether or not they had children, or time since diagnosis. Conclusion(s) This evidence supports the need for prospective controlled studies. Strategies to improve social support and self-esteem might provide a therapeutic approach to reduce the emotional suffering that accompanies the life-altering diagnosis of spontaneous primary ovarian insufficiency. PMID:18829005

Orshan, Susan A.; Ventura, June L.; Covington, Sharon N.; Vanderhoof, Vien H.; Troendle, James F.; Nelson, Lawrence M.

2009-01-01

221

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 ...

222

Control of the shape of the spatial mode function of photons generated in noncollinear spontaneous parametric down-conversion  

SciTech Connect

We show experimentally how the spatial shape of the pump beam controls the ellipticity of the spatial mode function in noncollinear spontaneous parametric down-conversion. The degree of ellipticity depends on the pump beam width, especially for highly focused beams. We introduce an effective length, the so-called noncollinear length, that determines the importance of the ellipticity of the spatial mode function. We also discuss the ellipticity induced by the spectrum of the pump beam.

Molina-Terriza, Gabriel; Minardi, Stefano; Osorio, Clara I. [ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona) (Spain); Deyanova, Yana; Hendrych, Martin; Torres, Juan P. [ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona) (Spain); Department of Signal Theory and Communications, Universitat Politecnica de Catalunya, 08034 Barcelona (Spain)

2005-12-15

223

Controlled and Spontaneous Magnetic Field Generation in a Gun-Driven Spheromak.  

NASA Astrophysics Data System (ADS)

In the Sustained Spheromak Physics Experiment, SSPX, progress has been made in understanding the mechanisms that generate fields by helicity injection [1][2]. SSPX injects helicity (linked magnetic flux) from a 1-m diameter magnetized coaxial gun into a flux-conserving confinement region. Control of magnetic fluctuations (?B/B<1%) yields Te profiles peaked at 200eV (2x higher than previously obtained [3]). Trends indicate a limiting beta (? _e ˜ 4%), so further increases of Te requires operating with higher fields. Two new operating modes are observed to increase the magnetic field: with constant current and spontaneous gun voltage fluctuations; and with current pulses to harness specific processes. In the first case, the gun is operated continuously at the ejection threshold: stored magnetic energy of the spheromak increases gradually with ?B/B ˜2% and large voltage fluctuations (?V ˜1kV), giving a 50% increase in current amplification, I_tor/I_gun. In the second case, we show that the B-field can be increased in a stepwise fashion by pulsing the gun. By increasing the timing between pulses, a quasi-steady sustainment is produced (with periodic good confinement), which we compare with 3D MHD simulations [4]. In each case, the processes that transport the helicity into the spheromak are inductive. Internal magnetic probing helps identify these processes and also show that the discharge in the gun can be asymmetric, causing a practical limitation in applying helicity balance. [1] S. Woodruff et al Phys. Rev. Lett. 90 095001-1 (2003); [2] B. W. Stallard et al Phys. of Plasmas 10 2912 (2003); [3] H. S. McLean, et al Phys. Rev. Lett. 88 125004 (2002); [4] R. Cohen et al to appear in Nuclear Fusion

Woodruff, Simon

2003-10-01

224

Integrated emissions control system for residential CWS furnace  

SciTech Connect

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.

Balsavich, J.C. Jr.

1991-11-01

225

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

NASA Astrophysics Data System (ADS)

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.

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

226

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 ...

227

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...

228

HEALTH AND CLIMATE POLICY IMPACTS ON SULFUR EMISSION CONTROL  

E-print Network

fuels not only has strong cooling effects on the Earth's climate but also imposes substantial costs the climate and health effects of sulfate aerosol into an integrated-assessment model of fossil fuel emission control. Our simulations show that a policy that adjusts fossil fuel and sulfur emissions to address both

Russell, Lynn

229

Control of variable geometry turbocharged diesel engines for reduced emissions  

Microsoft Academic Search

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

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

2000-01-01

230

40 CFR 52.1384 - Emission control regulations.  

Code of Federal Regulations, 2011 CFR

...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...

2011-07-01

231

40 CFR 52.1384 - Emission control regulations.  

Code of Federal Regulations, 2014 CFR

...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...

2014-07-01

232

40 CFR 52.1384 - Emission control regulations.  

Code of Federal Regulations, 2013 CFR

...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...

2013-07-01

233

40 CFR 52.1384 - Emission control regulations.  

Code of Federal Regulations, 2012 CFR

...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...

2012-07-01

234

40 CFR 52.1384 - Emission control regulations.  

Code of Federal Regulations, 2010 CFR

...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...

2010-07-01

235

The Control of NOx Emissions from Combustion and Incinerators  

E-print Network

THE CONTROL OF NO x EMISSIONS FROM COMBUSTORS AND INCINERATORS M. P. HEAP, S. L. CHEN, W. R. SEEKER, AND D. W. PERSHING Energy and Environmental Research Corporation 18 Mason, Irvine, California 92718 ABSTRACT The effectiveness...

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

236

A Novel New Approach to VOC and HAP Emission Control  

E-print Network

of real estate. Non-thermal VOHAP (Volatile Organic Hazardous Air Pollutant) emission control devices require additional maintenance. They also require the replacement of costly consumables such as activated carbon or they use large amounts of energy...

McGinness, M.

237

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 ...

238

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

SciTech Connect

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.

Rohringer, N

2008-08-08

239

40 CFR 63.325 - Determination of equivalent emission control technology.  

Code of Federal Regulations, 2010 CFR

...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...

2010-07-01

240

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

PubMed

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

Hau-Riege, Stefan P

2008-02-18

241

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

NASA Astrophysics Data System (ADS)

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 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.

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

2003-12-01

242

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

SciTech Connect

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.

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

243

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

PubMed

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

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

2011-06-10

244

Mapping the transverse coherence of the self amplified spontaneous emission of a free-electron laser with the heterodyne speckle method.  

PubMed

The two-dimensional single shot transverse coherence of the Self-Amplified Spontaneous Emission of the SPARC_LAB Free-Electron Laser was measured through the statistical analysis of a speckle field produced by heterodyning the radiation beam with a huge number of reference waves, scattered by a suspension of particles. In this paper we report the measurements and the evaluation of the transverse coherence along the SPARC_LAB undulator modules. The measure method was demonstrated to be precise and robust, it does not require any a priori assumptions and can be implemented over a wide range of wavelengths, from the optical radiation to the x-rays. PMID:25606931

Alaimo, Matteo D; Anania, Maria Pia; Artioli, Marcello; Bacci, Alberto; Bellaveglia, Marco; Ciocci, Franco; Chiadroni, Enrica; Cianchi, Alessandro; Dattoli, Giuseppe; Di Pirro, Giampierro; Ferrario, Massimo; Gatti, Giancarlo; Giannessi, Luca; Manfredda, Michele; Martucci, Roberta; Mostacci, Andrea; Paroli, Bruno; Petralia, Alberto; Petrillo, Vittoria; Pompili, Riccardo; Potenza, Marco A C; Quattormini, Marcello; Rau, Julietta; Redoglio, Daniele; Rossi, Andrea R; Serafini, Luca; Surrenti, Vincenzo; Torre, Amalia; Vaccarezza, Cristina; Villa, Fabio

2014-12-01

245

Solid state amplified spontaneous emission in some spiro-type molecules: A new concept for the design of solid state lasing molecules  

Microsoft Academic Search

Here are presented initial results on spectral narrowing in submicron thick neat films, of 2,2?,7,7?-tetraphenyl-9,9?-spirobifluorene (spiro-quarterphenyl) and 2,2?,7,7?-tetrakis(biphenyl-4-yl)-9,9-spirobiflourene (spiro-sexiphenyl). The luminescence effects reported here are common to several other molecules which belong the class of molecules known as the spiro-type molecules. The Amplified Spontaneous Emission (ASE) is evidenced by a dramatic collapse of the line width, when pumped with sufficient

N. Johansson; J. Salbeck; J. Bauer; F. Weissörtel; P. Bröms; A. Andersson; W. R. Salaneck

1999-01-01

246

THE JOURNAL OF CHEMICAL PHYSICS 141, 074107 (2014) Frequency-domain stimulated and spontaneous light emission signals  

E-print Network

at the nano scale by detecting various types of optical signals, for example, spontaneous and stimulated. Fluorescence has been used to detect and study single molecule dynamics1­3 which is governed by quantum effects in a scanning tunneling microscopy has been demonstrated experimentally.12­15 On the theoretical front, current

Mukamel, Shaul

247

Historical evaluation of vehicle emission control in Guangzhou based on a multi-year emission inventory  

NASA Astrophysics Data System (ADS)

The Guangzhou government adopted many vehicle emission control policies and strategies during the five-year preparation (2005-2009) to host the 2010 Asian Games. This study established a multi-year emission inventory for vehicles in Guangzhou during 2005-2009 and estimated the uncertainty in total vehicle emissions by taking the assumed uncertainties in fleet-average emission factors and annual mileage into account. In 2009, the estimated total vehicle emissions in Guangzhou were 313 000 (242 000-387 000) tons of CO, 60 900 (54 000-70 200) tons of THC, 65 600 (56 800-74 100) tons of NOx and 2740 (2100-3400) tons of PM10. Vehicle emissions within the urban area of Guangzhou were estimated to be responsible for ˜40% of total gaseous pollutants and ˜25% of total PM10 in the entire city. Although vehicle use intensity increased rapidly in Guangzhou during 2005-2009, vehicle emissions were estimated to have been reduced by 12% for CO, 21% for THC and 20% for PM10 relative to those in 2005. NOx emissions were estimated to have remained almost constant during this period. Compared to the "without control" scenario, 19% (15%-23%) of CO, 20% (18%-23%) of THC, 9% (8%-10%) of NOx and 16% (12%-20%) of PM10 were estimated to have been mitigated from a combination of the implementation of Euro III standards for light-duty vehicles (LDVs) and heavy-duty diesel vehicles and improvement of fuel quality. This study also evaluated several enhanced vehicle emission control actions taken recently. For example, the enhanced I/M program for LDVs was estimated to reduce 11% (9%-14%) of CO, 9% (8%-10%) of THC and 2% (2%-3%) of NOx relative to total vehicle emissions in 2009. Total emission reductions by temporary traffic controls for the Asian Games were estimated equivalent to 9% (7%-11%) of CO, 9% (8%-10%) of THC, 5% (5%-6%) of NOx and 10% (8%-13%) of PM10 estimated total vehicle emissions in 2009. Those controls are essential to further vehicle emission mitigation in Guangzhou required by the new National Ambient Air Quality Standards.

Zhang, Shaojun; Wu, Ye; Liu, Huan; Wu, Xiaomeng; Zhou, Yu; Yao, Zhiliang; Fu, Lixin; He, Kebin; Hao, Jiming

2013-09-01

248

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...

249

Biofiltration: An Innovative Air Pollution Control Technology For VOC Emissions  

Microsoft Academic Search

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

Gero Leson; Arthur M. Winer

1991-01-01

250

Optical control of the emission direction of a quantum dot  

SciTech Connect

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%.

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

251

On-demand optogenetic control of spontaneous seizures in temporal lobe epilepsy  

PubMed Central

Temporal lobe epilepsy is the most common type of epilepsy in adults, is often medically refractory, and due to broad actions and long-time scales, current systemic treatments have major negative side-effects. However, temporal lobe seizures tend to arise from discrete regions before overt clinical behaviour, making temporally and spatially specific treatment theoretically possible. Here we report the arrest of spontaneous seizures using a real-time, closed-loop, response system and in vivo optogenetics in a mouse model of temporal lobe epilepsy. Either optogenetic inhibition of excitatory principal cells, or activation of a subpopulation of GABAergic cells representing <5% of hippocampal neurons, stops seizures rapidly upon light application. These results demonstrate that spontaneous temporal lobe seizures can be detected and terminated by modulating specific cell populations in a spatially restricted manner. A clinical approach built on these principles may overcome many of the side-effects of currently available treatment options. PMID:23340416

Krook-Magnuson, Esther; Armstrong, Caren; Oijala, Mikko; Soltesz, Ivan

2013-01-01

252

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)

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.

Ibnaouf, K. H.

2015-04-01

253

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

E-print Network

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

Dirk Heinze; Artur Zrenner; Stefan Schumacher

2014-12-02

254

Coal-fueled diesel emissions control technology development  

SciTech Connect

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.

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

1993-01-01

255

Coal-fueled diesel emissions control technology development  

SciTech Connect

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.

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

1993-03-01

256

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

PubMed

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

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

1991-05-01

257

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

SciTech Connect

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 continuously vary the power applied to the oven to control the boiling at a selected level. 2 figs.

White, T.L.

1990-05-02

258

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

SciTech Connect

This patent describes an acoustic emission based feedback system for controlling the boiling level of a liquid medium in a microwave oven. 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 continuously vary the power applied to the oven to control the boiling at a selected level.

White, T.L.

1991-02-26

259

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

DOEpatents

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.

White, Terry L. (Oak Ridge, TN)

1991-01-01

260

Positional control of plasmonic fields and electron emission  

SciTech Connect

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.

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

261

Positional control of plasmonic fields and electron emission  

NASA Astrophysics Data System (ADS)

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.

Word, R. C.; Fitzgerald, J. P. S.; Könenkamp, R.

2014-09-01

262

Control of mercury vapor emissions from combustion flue gas  

Microsoft Academic Search

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

Rong Yan; David Tee Liang; Joo Hwa Tay

2003-01-01

263

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

NASA Astrophysics Data System (ADS)

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

Shetty, Suraj K.

264

24 CFR 3280.308 - Formaldehyde emission controls for certain wood products.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Formaldehyde emission controls for certain wood products. 3280.308 Section 3280.308 Housing and Urban...Requirements § 3280.308 Formaldehyde emission controls for certain wood products. (a) Formaldehyde emission levels. All...

2010-04-01

265

24 CFR 3280.308 - Formaldehyde emission controls for certain wood products.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Formaldehyde emission controls for certain wood products. 3280.308 Section 3280.308 Housing and Urban...Requirements § 3280.308 Formaldehyde emission controls for certain wood products. (a) Formaldehyde emission levels. All...

2012-04-01

266

24 CFR 3280.308 - Formaldehyde emission controls for certain wood products.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 false Formaldehyde emission controls for certain wood products. 3280.308 Section 3280.308 Housing and Urban...Requirements § 3280.308 Formaldehyde emission controls for certain wood products. (a) Formaldehyde emission levels. All...

2014-04-01

267

24 CFR 3280.308 - Formaldehyde emission controls for certain wood products.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Formaldehyde emission controls for certain wood products. 3280.308 Section 3280.308 Housing and Urban...Requirements § 3280.308 Formaldehyde emission controls for certain wood products. (a) Formaldehyde emission levels. All...

2011-04-01

268

24 CFR 3280.308 - Formaldehyde emission controls for certain wood products.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Formaldehyde emission controls for certain wood products. 3280.308 Section 3280.308 Housing and Urban...Requirements § 3280.308 Formaldehyde emission controls for certain wood products. (a) Formaldehyde emission levels. All...

2013-04-01

269

40 CFR 63.1316 - PET and polystyrene affected sources-emissions control provisions.  

Code of Federal Regulations, 2010 CFR

... true PET and polystyrene affected sources-emissions control provisions. 63...STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards...1316 PET and polystyrene affected sources—emissions control provisions....

2010-07-01

270

CONTROLLING AGRICULTURAL EMISSIONS OF METHYL BROMIDE.  

Technology Transfer Automated Retrieval System (TEKTRAN)

During the last 40 to 50 years, methyl bromide (MeBr) has been used to sterilize soils in preparation to planting various high-cash-value fruit and vegetable crops throughout the world. MeBr is a highly toxic chemical and is very effective in controlling a variety of soil-borne pests, such as nemato...

271

Plasmonic beaming and active control over fluorescent emission.  

PubMed

Nanometallic optical antennas are rapidly gaining popularity in applications that require exquisite control over light concentration and emission processes. The search is on for high-performance antennas that offer facile integration on chips. Here we demonstrate a new, easily fabricated optical antenna design that achieves an unprecedented level of control over fluorescent emission by combining concepts from plasmonics, radiative decay engineering and optical beaming. The antenna consists of a nanoscale plasmonic cavity filled with quantum dots coupled to a miniature grating structure that can be engineered to produce one or more highly collimated beams. Electromagnetic simulations and confocal microscopy were used to visualize the beaming process. The metals defining the plasmonic cavity can be utilized to electrically control the emission intensity and wavelength. These findings facilitate the realization of a new class of active optical antennas for use in new optical sources and a wide range of nanoscale optical spectroscopy applications. PMID:21505439

Jun, Young Chul; Huang, Kevin C Y; Brongersma, Mark L

2011-01-01

272

New emission controls for Missouri batch-type charcoal kilns  

SciTech Connect

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.

Yronwode, P.; Graf, W.J.

1999-07-01

273

Coal-fueled diesel technology development Emissions Control  

SciTech Connect

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.

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

1994-01-01

274

Coal-fueled diesel technology development emissions control  

NASA Astrophysics Data System (ADS)

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.

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

1994-01-01

275

Soil acidification in China: is controlling SO2 emissions enough?  

PubMed

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

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

2009-11-01

276

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

Code of Federal Regulations, 2011 CFR

...I determine the outlet THC emissions and add-on control device emission destruction...I determine the outlet THC emissions and add-on control device emission destruction...determine either the outlet THC emissions or add-on control device emission...

2011-07-01

277

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

NASA Astrophysics Data System (ADS)

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

Li, Guoqiang

278

NOx Sensor for Direct Injection Emission Control  

SciTech Connect

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.

Betteridge, William J

2006-02-28

279

PHYSICAL COAL CLEANING FOR UTILITY BOILER SO2 EMISSION CONTROL  

EPA Science Inventory

The report examines physical coal cleaning as a control technique for sulfur oxides emissions. It includes an analysis of the availability of low-sulfur coal and of coal cleanable to compliance levels for alternate New Source Performance Standards (NSPS). Various alternatives to ...

280

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...

281

Reversed flow converter for emission control after automotive engines  

Microsoft Academic Search

A concept of catalytic reversed flow converter (RFC) is discussed for three emerging areas of emission control after automotive engines. The first potential application concerns with oxidation of methane and CO emitted from dual fueled, natural gas\\/diesel engines (DDF). The behavior of RFC is studied under typical transient conditions of DDF engine exhaust using mathematical modeling and experiments with converter

Yu. Sh. Matros; G. A. Bunimovich; V. O. Strots; E. A. Mirosh

1999-01-01

282

Technology and emission properties of dispenser cathode with controlled porosity  

NASA Astrophysics Data System (ADS)

We report on a controlled porosity dispenser cathode using a new design and new manufacturing technology. Emission properties of this cathode in the temperature range of 800-1050°C are significantly greater than L, M and MM cathodes. Novel application of such kind of cathodes may be electron sources for multi-beam klystrons, TWTs, linear accelerators etc.

Chubun, N. N.; Sudakova, L. N.

1997-02-01

283

40 CFR 52.987 - Control of hydrocarbon emissions.  

Code of Federal Regulations, 2010 CFR

...from service of a 10,000 barrel capacity crude oil storage tank at the Belcher Station...from service of a 55,000 barrel capacity crude oil storage tank at the Weller Station...Installation of emission control systems on crude oil storage tanks TK-43,...

2010-07-01

284

40 CFR 52.987 - Control of hydrocarbon emissions.  

Code of Federal Regulations, 2012 CFR

...from service of a 10,000 barrel capacity crude oil storage tank at the Belcher Station...from service of a 55,000 barrel capacity crude oil storage tank at the Weller Station...Installation of emission control systems on crude oil storage tanks TK-43,...

2012-07-01

285

40 CFR 52.987 - Control of hydrocarbon emissions.  

Code of Federal Regulations, 2011 CFR

...from service of a 10,000 barrel capacity crude oil storage tank at the Belcher Station...from service of a 55,000 barrel capacity crude oil storage tank at the Weller Station...Installation of emission control systems on crude oil storage tanks TK-43,...

2011-07-01

286

40 CFR 57.702 - Compliance with constant control emission limitation.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Compliance with constant control emission limitation. 57...Requirements § 57.702 Compliance with constant control emission limitation. ...achieving compliance with interim SO2 constant controls including gas capacity...

2010-07-01

287

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

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.

H. J. Zhao; M. L. Du

2006-12-18

288

Control of volatile organic compound emissions from batch processes. Alternative control techniques information document. Final report  

SciTech Connect

The purpose of this document is to provide information on alternative control techniques for volatile organic compound (VOC) emissions from batch operations. Although the control techniques information applies to batch processing in all industries, the document focuses primarily on batch processes in the following six industries: plastic materials and resins (described by Standard Industrial Classification (SIC) Code 2821), pharmaceuticals (SIC 2833 and 2834), gum and wood chemicals (SIC 2861), cyclic crudes and intermediates (SIC 2865), industrial organic chemicals (2869), and agricultural chemicals (SIC 2879). The document contains information on emissions, controls, control options, and costs that States can use in developing rules based on reasonably available control technology.

Not Available

1994-02-01

289

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

NASA Astrophysics Data System (ADS)

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.

Mohtashami, Abbas; Femius Koenderink, A.

2013-04-01

290

Gamma Ray Multiplicity Comparison of a 2-Neutron and a 4-Neutron Emission ^252Cf Spontaneous Fission  

NASA Astrophysics Data System (ADS)

The correlation between ?-ray multiplicity and neutron multiplicity in the fission process is not currently well known. Competing theories predict opposite correlations and experiments have measured only average properties. We have measured the ?-ray multiplicity spectrum of ^252Cf spontaneous fission using the LiBerACE array, comprised of six high-purity germanium (HPGe) Clover detectors, each surrounded by 16 bismuth-germanate (BGO) detectors. The Clovers were arranged in a cubic pattern around a 1 ?Ci ^252Cf source. Neutron multiplicity was determined for two cases by identifying known correlated fission products from prompt ?-rays observed in the HPGe detectors. No difference in the ?-ray multiplicity spectrum was observed for fissions that produced ^106Mo/^144Ba (2 neutrons) compared to those producing ^106Mo/^142Ba (4 neutrons).

Bleuel, D. L.; Bernstein, L. A.; Burke, J. T.; Heffner, M. D.; Norman, E. B.; Scielzo, N. D.; Sheets, S. A.; Snyderman, N. J.; Stoyer, M. A.; Wiedeking, M.; Gibelin, J.; Phair, L. W.; Mintz, J.

2008-10-01

291

Control of air pollution emissions from municipal waste combustors  

SciTech Connect

The November 1990 Clear Air Act Amendments (CAAAs) directed EPA to establish municipal waste combustor (MWC) emissions limits for particulate matter, opacity, hydrogen chloride, sulfur dioxide, nitrogen oxides, carbon monoxide, dioxins, dibenzofurans, cadmium, lead, and mercury. Revised MWC air pollution regulations were subsequently proposed by EPA on September 20, 1994, and promulgated on December 19, 1995. The MWC emission limits were based on the application of maximum achievable control technology (MACT). This paper provides a brief overview of MWC technologies, a summary of EPA`s revised air pollution rules for MWCs, a review of current knowledge concerning formation and control of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans, and a discussion of the behavior and control of mercury in MWC flue gases. 56 refs., 11 figs., 3 tabs.

Kolgroe, J.D. [Environmental Protection Agency, Research Triangle Park, NC (United States). National Risk Management Research Lab.; Licata, A. [Licata Energy and Environmental Consultants, Inc., Yonkers, NY (United States)

1996-09-01

292

Air emission control equipment - the new challenge for equpiment suppliers  

SciTech Connect

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

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

1997-12-31

293

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

PubMed

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

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

2014-04-01

294

Soil acidification in China: Is controlling SO2 emissions enough?  

NASA Astrophysics Data System (ADS)

Facing challenges of 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 (SO2) emissions from 2005 to 2010. In this study, 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 SO2, oxides of nitrogen (NOX), particulate matter (PM), and ammonia (NH3) 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 SO2 and PM emissions, while those of NOX and NH3 will continue to rise, even under tentatively proposed control measures. In 2005, the critical load for soil acidification caused by sulfur deposition (indicated by CLmax(S)) 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 (combining effects of eutrophication and acidification, indicated by CL(N)) will double from 2005 to 2020 due to increased NOX and NH3 emissions. Combining the acidification effects of S and N(indicated by CL(S)), the benefits of SO2 reductions during 2005-2010 will almost be negated by increased N emissions. Therefore abatement of N emissions (both NOX and NH3) and deposition will be a major challenge to China, requiring both policy development and technology investments. To mitigate acidification in the future, China needs a multi-pollutant control strategy that integrates measures to reduce S, N and PM. Exceedances of critical loads for acidification and nutrient nitrogen in 2005, 2010, and 2020. Critical load exceedance in 2005, 2010 and 2020

Zhao, Y.; Duan, L.; Xing, J.; Larssen, T.; Nielsen, C. P.; Hao, J.

2009-12-01

295

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)

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.

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

2014-03-01

296

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)

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.

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

2014-09-01

297

Control of Several Emissions during Olive Pomace Thermal Degradation  

PubMed Central

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

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

2014-01-01

298

Ozone trends in Atlanta, Georgia - Have emission controls been effective?  

NASA Technical Reports Server (NTRS)

Nine years of summertime ozone data from the Atlanta metropolitan area are analyzed and compared to local emissions of volatile organic carbon and nitrogen oxides. Trends from 1979 to 1987 were studied for the number of days per year ozone exceeded the NAAQS standard, the second-highest ozone level observed per year, and the first quartile summertime average ozone observed, as well as the mean difference between the ozone level observed downwind and upwind of the city. Because this last parameter is sensitive to chemical factors but relatively insensitive to the number of days each year with meteorological conditions conducive to ozone formation, its trend may be best suited for determining how effective emission controls have been in reducing O3 in the Atlanta area. In spite of the fact that sizeable reductions have been claimed for volatile organic carbon emissions over the past several years, the data give no indication that ozone levels have decreased and in fact, imply that summertime ozone production may have increased. The results imply that either emissions have not decreased as much as has been claimed or that ozone is not sensitive to anthropogenic volatile organic carbon emissions.

Lindsay, Ronald W.; Richardson, Jennifer L.; Chameldes, William L.

1989-01-01

299

Control of several emissions during olive pomace thermal degradation.  

PubMed

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

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

2014-01-01

300

Venturi/vortex technology for controlling chromium electroplating emissions  

SciTech Connect

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

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

1997-12-31

301

Ultralow-threshold two-photon pumped amplified spontaneous emission and lasing from seeded CdSe/CdS nanorod heterostructures.  

PubMed

Ultralow-threshold two-photon pumped amplified spontaneous emission (2ASE) and lasing in seeded CdSe/CdS nanodot/nanorod heterostructures is demonstrated for the first time. Such heterostructures allow the independent tunability of the two-photon absorption (2PA) cross-section (?(2)) through varying the CdS rod size, and that of the emission wavelength through varying the CdSe dot size. With an enhanced ?(2), 2ASE in these heterostructures is achieved with an ultralow threshold fluence of ~1.5 mJ/cm(2), which is as much as one order less than that required for spherical semiconductor NCs. Importantly, by exploiting this unique property of the seeded nanorods exhibiting strong quantum confinement even at relatively large rod sizes, a near reciprocal relation between the 2ASE threshold and the 2PA action cross-section (?(2)?) (where ? is the quantum yield) was found and validated over a wide volume range for II-VI semiconductor nanostructures. Ultrafast optical spectroscopy verified that while the Auger processes in these heterostructures are indeed suppressed, ASE in these samples could also be strongly affected by a fast hole-trapping process to the NR surface states. Lastly, to exemplify the potential of these seeded CdSe/CdS nanodot/nanorod heterostructures as a viable gain media for achieving two-photon lasing, a highly photostable microsphere laser with an ultralow pump threshold is showcased. PMID:23157595

Xing, Guichuan; Liao, Yile; Wu, Xiangyang; Chakrabortty, Sabyasachi; Liu, Xinfeng; Yeow, Edwin K L; Chan, Yinthai; Sum, Tze Chien

2012-12-21

302

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

PubMed Central

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

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

2013-01-01

303

Rotary Cement Kiln Control for Reducing NOx Emissions to Atmosphere  

Microsoft Academic Search

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

Fragiskos A. Batzias

2006-01-01

304

40 CFR 63.985 - Nonflare control devices used to control emissions from storage vessels and low throughput...  

Code of Federal Regulations, 2010 CFR

... false Nonflare control devices used to control emissions...Closed Vent Systems, Control Devices, Recovery Devices and Routing...stream is introduced with the primary fuel. (3) Prior design... (c) Nonflare control device monitoring...

2010-07-01

305

40 CFR 63.985 - Nonflare control devices used to control emissions from storage vessels and low throughput...  

Code of Federal Regulations, 2013 CFR

... false Nonflare control devices used to control emissions...Closed Vent Systems, Control Devices, Recovery Devices and Routing...stream is introduced with the primary fuel. (3) Prior design... (c) Nonflare control device monitoring...

2013-07-01

306

40 CFR 63.985 - Nonflare control devices used to control emissions from storage vessels and low throughput...  

Code of Federal Regulations, 2012 CFR

... false Nonflare control devices used to control emissions...Closed Vent Systems, Control Devices, Recovery Devices and Routing...stream is introduced with the primary fuel. (3) Prior design... (c) Nonflare control device monitoring...

2012-07-01

307

40 CFR 63.985 - Nonflare control devices used to control emissions from storage vessels and low throughput...  

Code of Federal Regulations, 2014 CFR

... false Nonflare control devices used to control emissions...Closed Vent Systems, Control Devices, Recovery Devices and Routing...stream is introduced with the primary fuel. (3) Prior design... (c) Nonflare control device monitoring...

2014-07-01

308

40 CFR 63.985 - Nonflare control devices used to control emissions from storage vessels and low throughput...  

Code of Federal Regulations, 2011 CFR

... false Nonflare control devices used to control emissions...Closed Vent Systems, Control Devices, Recovery Devices and Routing...stream is introduced with the primary fuel. (3) Prior design... (c) Nonflare control device monitoring...

2011-07-01

309

78 FR 5303 - Approval and Promulgation of Implementation Plans; State of Missouri; Control of Sulfur Emissions...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Control of Sulfur Emissions From Stationary Boilers AGENCY: Environmental Protection Agency...to PM 2.5 ), from industrial boilers. EPA is approving this revision...Control of Sulfur Emissions from Stationary Boilers to the SIP. This rule reduces the...

2013-01-25

310

Controlling Emission Zone in Blue OLEDs by Material Design  

NASA Astrophysics Data System (ADS)

The blue component is one of the remaining challenges for the organic light emitting devices (OLED) based solid-state lighting technology. OLEDs have the potential to generate solid state white lighting with 50% power conversion efficiency. However realizing this potential will require optimization of not only blue emitter dopants but also host matrices. Charge balance is a key factor in achieving high quantum efficiency and low operating voltage in OLED devices. In this work, we studied the effect of the chemical structure of the phosphine oxide-based hosts and electron transport materials on the location of the emission zone. We observed that a strong domination of one carrier within the host results in highly localized emission zones in OLEDs. As a result, an alteration of the chemical design of the materials allows for the control of the emissive region location within the EML. By chemical modification of the host molecule, we achieved a relocation of the emissive zone in blue OLEDs from the EML/ETL interface to the EML/HTL interface.

Padmaperuma, Asanga; Polikarpov, Evgueni; Swensen, James; Cosimbescu, Lelia; Koech, Phillip; Wang, Liang

2010-03-01

311

Active Control of Combustor Instability Shown to Help Lower Emissions  

NASA Technical Reports Server (NTRS)

In a quest to reduce the environmental impact of aerospace propulsion systems, extensive research is being done in the development of lean-burning (low fuel-to-air ratio) combustors that can reduce emissions throughout the mission cycle. However, these lean-burning combustors have an increased susceptibility to thermoacoustic instabilities, or high-pressure oscillations much like sound waves, that can cause severe high-frequency vibrations in the combustor. These pressure waves can fatigue the combustor components and even the downstream turbine blades. This can significantly decrease the safe operating life of the combustor and turbine. Thus, suppression of the thermoacoustic combustor instabilities is an enabling technology for lean, low-emissions combustors. Under the Aerospace Propulsion and Power Base Research and Technology Program, the NASA Glenn Research Center, in partnership with Pratt & Whitney and United Technologies Research Center, is developing technologies for the active control of combustion instabilities. With active combustion control, the fuel is pulsed to put pressure oscillations into the system. This cancels out the pressure oscillations being produced by the instabilities. Thus, the engine can have lower pollutant emissions and long life.The use of active combustion instability control to reduce thermo-acoustic-driven combustor pressure oscillations was demonstrated on a single-nozzle combustor rig at United Technologies. This rig has many of the complexities of a real engine combustor (i.e., an actual fuel nozzle and swirler, dilution cooling, etc.). Control was demonstrated through modeling, developing, and testing a fuel-delivery system able to the 280-Hz instability frequency. The preceding figure shows the capability of this system to provide high-frequency fuel modulations. Because of the high-shear contrarotating airflow in the fuel injector, there was some concern that the fuel pulses would be attenuated to the point where they would not be effective for control. Testing in the combustor rig showed that open-loop pulsing of the fuel was, in fact, able to effectively modulate the combustor pressure. To suppress the combustor pressure oscillations due to thermoacoustic instabilities, it is desirable to time the injection of the fuel so that it interferes with the instability. A closed-loop control scheme was developed that uses combustion pressure feedback and a phase-shifting controller to time the fuel-injection pulses. Some suppression of the pressure oscillations at the 280-Hz instability frequency was demonstrated (see the next figure). However, the overall peak-to- peak pressure oscillations in the combustor were only mildly reduced. Improvements to control hardware and control methods are being continued to gain improved closed-loop reduction of the pressure oscillations.pulse the fuel at

DeLaat, John C.; Chang, Clarence T.

2002-01-01

312

Technology for CO{sub 2} emission monitoring and control  

SciTech Connect

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.

Joyce, E.L. Jr.; Unkefer, P.J.; Pendergrass, J.H.; Parkinson, W.J.; Loose, V.W.; Brainard, J.R.

1998-12-31

313

Emission control of gas effluents from geothermal power plants.  

PubMed

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

Axtmann, R C

1975-01-01

314

Practical primer on design of electric arc furnace emission control systems  

Microsoft Academic Search

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:

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

1994-01-01

315

Optical nanoantennas: controlled emission of single photon sources  

NASA Astrophysics Data System (ADS)

Nanoscale quantum emitters are key elements in quantum optics and sensing. However, efficient optical excitation and detection of such emitters involves large solid angles, due to their omnidirectional interaction with freely propagating light and due to limits of diffraction. Optical nanoantennas offer both nanoscale localization and efficient interaction. Here we focus on the control of the interaction of single photon emitters (molecules, quantum dots) with radiation through metal nanorod antennas. First a novel analytical model is presented, which shows the continuous evolution of the properties of optical antennas as they become increasingly bound, i.e. plasmonic. The model accurately describes the complete emission process, the radiative decay rate, quantum efficiency, and angular emission, moreover gives a quantitative description of the gradual emergence of sub-radiant, super-radiant, and dark modes. Next we investigate experimentally the coupling of a single quantum dot to a nanorod of increasing length. The angular luminescence of the quantum dot is detected through increasingly higher order antenna modes. Simultaneously the emission is strongly polarized and enhanced. Direct confrontation with theory allows to determine the coupling efficiency of the quantum dot to the antenna. Finally, we present unidirectional emission of a single emitter by coupling to a nanofabricated Yagi-Uda antenna. A quantum dot is placed in the near field of the antenna so that it drives the resonant feed element of the antenna. The resulting quantum-dot luminescence is strongly polarized and highly directed into a narrow forward angular cone. The directionality of the quantum dot can be controlled by tuning the antenna dimensions. Thus our results show the potential of optical antennas to communicate energy to, from, and between nano-emitters. [4pt] A.G.Curto et al., Science 329, 930 (2010)

van Hulst, Niek

2011-03-01

316

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...

317

Dopamine and inhibitory action control: evidence from spontaneous eye blink rates  

Microsoft Academic Search

The inhibitory control of actions has been claimed to rely on dopaminergic pathways. Given that this hypothesis is mainly\\u000a based on patient and drug studies, some authors have questioned its validity and suggested that beneficial effects of dopaminergic\\u000a stimulants on response inhibition may be limited to cases of suboptimal inhibitory functioning. We present evidence that,\\u000a in carefully selected healthy adults,

Lorenza Serena Colzato; Wery P. M. van den Wildenberg; Nelleke C. van Wouwe; Merel M. Pannebakker; Bernhard Hommel

2009-01-01

318

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

PubMed

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

Kumar, Vinit; Krishnagopal, Srinivas

2002-01-01

319

Self-assembly, highly modified spontaneous emission and energy transfer properties of LaPO4:Ce3+, Tb3+ inverse opals.  

PubMed

The modification of photonic crystals (PCs) on photoluminescence of rare earth (RE) ions has attracted considerable interest, however, the modification of PCs on energy transfer (ET) processes of two separate RE centers has not been investigated yet. In this paper, three-dimensional Ce(3+), Tb(3+)-codoped LaPO4 inverse opal PCs (IOPCs) were fabricated by the PMMA colloidal template method. The modification of the photonic stop band (PSB) on emission spectra and the dynamics of the 5d-4f transition of Ce(3+) and the 4f-4f transition of Tb(3+) ions were systematically studied. It is interesting to observe that the spontaneous decay rates (SDR) of (5)D4-(7)F5 in the IOPCs were suppressed as highly as 173% in contrast to the reference ground powder samples (REF) due to the modification of the effective refractive index (n(eff)). The energy transfer (ET) rate of Ce(3+) to Tb(3+) did not change in the IOPCs, however, the energy migration rate among Tb(3+) ions was largely restrained. It is also significant to observe that, in the IOPCs, the temperature quenching and radiation trapping of photoluminescence were greatly suppressed due to the periodic empty cavity structure of IOPCs, which is significant for high-power light sources and laser devices. PMID:23571776

Zhu, Yongsheng; Sun, Zhipeng; Yin, Ze; Song, Hongwei; Xu, Wen; Wang, Yunfeng; Zhang, Ligong; Zhang, Hanzhuang

2013-06-14

320

40 CFR 65.145 - Nonflare control devices used to control emissions from storage vessels or low-throughput...  

Code of Federal Regulations, 2010 CFR

... false Nonflare control devices used to control emissions...Closed Vent Systems, Control Devices, and Routing to a Fuel Gas...stream is introduced with the primary fuel. (3) Halogen reduction devices used for transfer...

2010-07-01

321

40 CFR 65.145 - Nonflare control devices used to control emissions from storage vessels or low-throughput...  

Code of Federal Regulations, 2014 CFR

... false Nonflare control devices used to control emissions...Closed Vent Systems, Control Devices, and Routing to a Fuel Gas...stream is introduced with the primary fuel. (3) Halogen reduction devices used for transfer...

2014-07-01

322

40 CFR 65.145 - Nonflare control devices used to control emissions from storage vessels or low-throughput...  

Code of Federal Regulations, 2013 CFR

... false Nonflare control devices used to control emissions...Closed Vent Systems, Control Devices, and Routing to a Fuel Gas...stream is introduced with the primary fuel. (3) Halogen reduction devices used for transfer...

2013-07-01

323

40 CFR 65.145 - Nonflare control devices used to control emissions from storage vessels or low-throughput...  

Code of Federal Regulations, 2011 CFR

... false Nonflare control devices used to control emissions...Closed Vent Systems, Control Devices, and Routing to a Fuel Gas...stream is introduced with the primary fuel. (3) Halogen reduction devices used for transfer...

2011-07-01

324

40 CFR 65.145 - Nonflare control devices used to control emissions from storage vessels or low-throughput...  

Code of Federal Regulations, 2012 CFR

... false Nonflare control devices used to control emissions...Closed Vent Systems, Control Devices, and Routing to a Fuel Gas...stream is introduced with the primary fuel. (3) Halogen reduction devices used for transfer...

2012-07-01

325

A new method to thermally manage an electronic control unit while reducing radiated emissions  

Microsoft Academic Search

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

Imad Sharaa; Daniel N. Aloi

2008-01-01

326

Implementing Strategies for Drying and Pressing Wood Without Emissions Controls  

SciTech Connect

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.

Sujit Banerjee; Terrance Conners

2007-09-07

327

40 CFR 63.325 - Determination of equivalent emission control technology.  

Code of Federal Regulations, 2014 CFR

...63.325 Determination of equivalent emission control technology...or procedures be considered equivalent to the requirements under...that the alternative achieves equivalent emission reductions...Solvent mileage is the average weight of articles cleaned...

2014-07-01

328

40 CFR 63.325 - Determination of equivalent emission control technology.  

Code of Federal Regulations, 2013 CFR

...63.325 Determination of equivalent emission control technology...or procedures be considered equivalent to the requirements under...that the alternative achieves equivalent emission reductions...Solvent mileage is the average weight of articles cleaned...

2013-07-01

329

40 CFR 63.325 - Determination of equivalent emission control technology.  

Code of Federal Regulations, 2011 CFR

...63.325 Determination of equivalent emission control technology...or procedures be considered equivalent to the requirements under...that the alternative achieves equivalent emission reductions...Solvent mileage is the average weight of articles cleaned...

2011-07-01

330

40 CFR 63.325 - Determination of equivalent emission control technology.  

Code of Federal Regulations, 2012 CFR

...63.325 Determination of equivalent emission control technology...or procedures be considered equivalent to the requirements under...that the alternative achieves equivalent emission reductions...Solvent mileage is the average weight of articles cleaned...

2012-07-01

331

Plasmonic control of light emission for enhanced efficiency and beam shaping  

NASA Astrophysics Data System (ADS)

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.

DiMaria, Jeffrey V.

332

Carbon bed mercury emissions control for mixed waste treatment.  

PubMed

Mercury has various uses in nuclear fuel reprocessing and other nuclear processes, and so it is often present in radioactive and mixed (radioactive and hazardous) wastes. Compliance with air emission regulations such as the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards can require off-gas mercury removal efficiencies up to 99.999% for thermally treating some mixed waste streams. Test programs have demonstrated this level of off-gas mercury control using fixed beds of granular sulfur-impregnated activated carbon. Other results of these tests include (1) the depth of the mercury control mass transfer zone was less than 15-30 cm for the operating conditions of these tests; (2) MERSORB carbon can sorb mercury up to 19 wt % of the carbon mass; and (3) the spent carbon retained almost all (98.3-99.99%) of the mercury during Toxicity Characteristic Leachability Procedure (TCLP) tests, but when even a small fraction of the total mercury dissolves, the spent carbon can fail the TCLP test when the spent carbon contains high mercury concentrations. PMID:21141428

Soelberg, Nick; Enneking, Joe

2010-11-01

333

Quality control of positron emission tomography radiopharmaceuticals: An institutional experience  

PubMed Central

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

Shukla, Jaya; Vatsa, Rakhee; Garg, Nitasha; Bhusari, Priya; Watts, Ankit; Mittal, Bhagwant R

2013-01-01

334

Emission control catalyst derived from mesoporous molecular sieves  

SciTech Connect

A lean NO{sub x} catalyst is needed to control NO{sub x} emissions generated by oxygen-rich combustion processes to obtain higher fuel economy. The authors have developed such a catalyst using modified mesoporous molecular sieves (MCM-41). An iron(II)-complex impregnated MCM-41 has been synthesized which has been further treated with [Pd(NH{sub 3}){sub 4}]Cl{sub 2}. This treatment resulted in further exchange of Na{sup +} ions of the molecular sieves with Pd(NH{sub 3}){sub 4}{sup 2+} thus forming Catalyst A. The catalytic activity towards NO{sub x}, CO and HC was studied using simulated exhaust gas, as well as engine exhaust gas.

Paul, P.P.; Miller, M.A.; Heimrich, M.J.; Schwab, S.T. [Southwest Research Inst., San Antonio, TX (United States). Materials Engineering Dept.

1996-12-31

335

Application of microturbines to control emissions from associated gas  

DOEpatents

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.

Schmidt, Darren D.

2013-04-16

336

Controlling satellite communication system unwanted emissions in congested RF spectrum  

NASA Astrophysics Data System (ADS)

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

Olsen, Donald; Heymann, Roger

2007-09-01

337

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

Code of Federal Regulations, 2012 CFR

...controlled hourly NOX emission rate (MCR) or 1.25 times the maximum hourly controlled...2.2 of appendix A to this part. The MCR shall be calculated according to the basic...maximum controlled NOX emission rate (MCR)” and the NOX MEC shall be used...

2012-07-01

338

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

Code of Federal Regulations, 2013 CFR

...controlled hourly NOX emission rate (MCR) or 1.25 times the maximum hourly controlled...2.2 of appendix A to this part. The MCR shall be calculated according to the basic...maximum controlled NOX emission rate (MCR)” and the NOX MEC shall be used...

2013-07-01

339

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

Code of Federal Regulations, 2014 CFR

...controlled hourly NOX emission rate (MCR) or 1.25 times the maximum hourly controlled...2.2 of appendix A to this part. The MCR shall be calculated according to the basic...maximum controlled NOX emission rate (MCR)” and the NOX MEC shall be used...

2014-07-01

340

The next decade and emission controls for electric utilities  

SciTech Connect

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.

Herrin, W.D. [Southern Company Services, Birmingham, AL (United States)

1997-12-31

341

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

SciTech Connect

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.

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

2008-09-15

342

Optical sensors for process control and emissions monitoring in industry  

SciTech Connect

Sandia National Laboratories has a number of ongoing projects developing optical sensors for industrial environments. Laser-based sensors can be attractive for relatively harsh environments where extractive sampling is difficult, inaccurate, or impractical. Tools developed primarily for laboratory research can often be adapted for the real world and applied to problems far from their original uses. Spectroscopic techniques, appropriately selected, have the potential to impact the bottom line of a number of industries and industrial processes. In this paper the authors discuss three such applications: a laser-based instrument for process control in steelmaking, a laser-induced breakdown method for hazardous metal detection in process streams, and a laser-based imaging sensor for evaluating surface cleanliness. Each has the potential to provide critical, process-related information in a real-time, continuous manner. These sensor techniques encompass process control applications and emissions monitoring for pollution prevention. They also span the range from a field-tested pre-commercial prototype to laboratory instrumentation. Finally, these sensors employ a wide range of sophistication in both the laser source and associated analytical spectroscopy. In the ultimate applications, however, many attributes of the sensors are in common, such as the need for robust operation and hardening for harsh industrial environments.

S. W. Alendorf; D. K. Ottensen; D. W. Hahn; T. J. Kulp; U. B. Goers

1999-01-01

343

Optical sensors for process control and emissions monitoring in industry  

SciTech Connect

Sandia National Laboratories has a number of ongoing projects developing optical sensors for industrial environments. Laser-based sensors can be attractive for relatively harsh environments where extractive sampling is difficult, inaccurate, or impractical. Tools developed primarily for laboratory research can often be adapted for the real world and applied to problems far from their original uses. Spectroscopic techniques, appropriately selected, have the potential to impact the bottom of line of a number of industries and industrial processes. In this paper the authors discuss three such applications: a laser-based instrument for process control in steelmaking, a laser-induced breakdown method for hazardous metal detection in process streams, and a laser-based imaging sensor for evaluating surface cleanliness. Each has the potential to provide critical, process-related information in a real-time, continuous manner. These sensor techniques encompass process control applications and emissions monitoring for pollution prevention. They also span the range from a field-tested pre-commercial prototype to laboratory instrumentation. Finally, these sensors employ a wide range of sophistication in both the laser source and associated analytical spectroscopy. In the ultimate applications, however, many attributes of the sensors are in common, such as the need for robust operation and hardening for harsh industrial environments.

S. W. Allendorf; D. K. Ottesen; D. W. Hahn; T. J. Kulp; U. B. Goers

1998-11-02

344

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

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.

Ming Zhang; Zhan-Ying Yang; Rui-Hong Yue

2014-07-04

345

Randomized controlled trial of probiotics for the prevention of spontaneous preterm delivery associated with intrauterine infection: study protocol  

Microsoft Academic Search

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

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

346

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...

347

How light, temperature, and measurement and growth [CO2] interactively control isoprene emission in hybrid aspen.  

PubMed

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

Niinemets, Ülo; Sun, Zhihong

2015-02-01

348

OVERVIEW OF ADVANCED PETROLEUM-BASED FUELS-DIESEL EMISSIONS CONTROL PROGRAM (APBF-DEC)  

SciTech Connect

The Advanced Petroleum-Based Fuels-Diesel Emissions Control Program (APBF-DEC) began in February 2000 and is supported by government agencies and industry. The purpose of the APBF-DEC program is to identify and evaluate the optimal combinations of fuels, lubricants, diesel engines, and emission control systems to meet the projected emission standards for the 2000 to 2010 time period. APBF-DEC is an outgrowth of the earlier Diesel Emission Control-Sulfur Effects Program (DECSE), whose objective is to determine the impact of the sulfur levels in fuel on emission control systems that could lower the emissions of NOx and particulate matter (PM) from diesel powered vehicles in the 2002 to 2004 period. Results from the DECSE studies of two emission control technologies-diesel particle filter (DPF) and NOx adsorber-will be used in the APBF-DEC program. These data are expected to provide initial information on emission control technology options and the effects of fuel properties (including additives) on the performance of emission control systems.

Sverdrup, George M.

2000-08-20

349

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

E-print Network

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 ...

Nam, Kyung-Min

350

Marine omega-3 polyunsaturated fatty acids induce sex-specific changes in reinforcer-controlled behaviour and neurotransmitter metabolism in a spontaneously hypertensive rat model of ADHD  

PubMed Central

Background Previous reports suggest that omega-3 (n-3) polyunsaturated fatty acids (PUFA) supplements may reduce ADHD-like behaviour. Our aim was to investigate potential effects of n-3 PUFA supplementation in an animal model of ADHD. Methods We used spontaneously hypertensive rats (SHR). SHR dams were given n-3 PUFA (EPA and DHA)-enriched feed (n-6/n-3 of 1:2.7) during pregnancy, with their offspring continuing on this diet until sacrificed. The SHR controls and Wistar Kyoto (WKY) control rats were given control-feed (n-6/n-3 of 7:1). During postnatal days (PND) 25–50, offspring were tested for reinforcement-dependent attention, impulsivity and hyperactivity as well as spontaneous locomotion. The animals were then sacrificed at PND 55–60 and their neostriata were analysed for monoamine and amino acid neurotransmitters with high performance liquid chromatography. Results n-3 PUFA supplementation significantly enhanced reinforcement-controlled attention and reduced lever-directed hyperactivity and impulsiveness in SHR males whereas the opposite or no effects were observed in females. Analysis of neostriata from the same animals showed significantly enhanced dopamine and serotonin turnover ratios in the male SHRs, whereas female SHRs showed no change, except for an intermediate increase in serotonin catabolism. In contrast, both male and female SHRs showed n-3 PUFA-induced reduction in non-reinforced spontaneous locomotion, and sex-independent changes in glycine levels and glutamate turnover. Conclusions Feeding n-3 PUFAs to the ADHD model rats induced sex-specific changes in reinforcement-motivated behaviour and a sex-independent change in non-reinforcement-associated behaviour, which correlated with changes in presynaptic striatal monoamine and amino acid signalling, respectively. Thus, dietary n-3 PUFAs may partly ameliorate ADHD-like behaviour by reinforcement-induced mechanisms in males and partly via reinforcement-insensitive mechanisms in both sexes. PMID:23228189

2012-01-01

351

Energy, Carbon-emission and Financial Savings from Thermostat Control  

SciTech Connect

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.

Blasing, T J [ORNL; Schroeder, Dana [University of Georgia, Athens, GA

2013-08-01

352

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...

353

Engine Performance (Section C: Emission Control Systems). Auto Mechanics Curriculum Guide. Module 3. Instructor's Guide.  

ERIC Educational Resources Information Center

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;…

Rains, Larry

354

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

ERIC Educational Resources Information Center

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…

Bacon, E. Miles

355

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...

356

STRUCTURAL TRANSFORMATIONS IN CA-BASED SORBENTS USED FOR SO2 EMISSION CONTROL  

EPA Science Inventory

The paper discusses structural transformations in Ca-based sorbents used for SO2 emission control. conomizer temperature injection of Ca-based sorbents is an option for dry control of SO2 emissions from coal-fired boilers. heir reactivity with SO2 was found to be a function of th...

357

THz emission from coherently controlled photocurrents in GaAs D. Co^tea)  

E-print Network

THz emission from coherently controlled photocurrents in GaAs D. Co^te´a) and J. M. FraserAs at 295 K. For 90 fs, 1550 and 775 nm optical pulses, we obtain phase-controllable near-single cycle 4 THz radiation. Higher frequency THz emission should be achievable with shorter pulses. At a 250 kHz repetition

Van Driel, Henry M.

358

Preface: Special Issue on Catalytic Control of Lean-Burn Engine Exhaust Emissions  

SciTech Connect

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.

Yezerets, Aleksey; Peden, Charles HF; Szanyi, Janos; Nova, Isabella; Epling, Bill

2012-04-30

359

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

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Units with add-on emission controls. 75.34 Section...Substitution Procedures § 75.34 Units with add-on emission controls. (a) The owner or operator of an affected unit equipped with add-on SO2 and/or NOX...

2011-07-01

360

Spatial Control of Coherent Anti-Stokes Emission with Height-Modulated Gold  

E-print Network

Spatial Control of Coherent Anti-Stokes Emission with Height-Modulated Gold Zig-Zag Nanowires used specially fabricated gold nanozigzag wires that are modulated in height between 20 and 80 nm to demonstrate tuning of the plasmon polarizability through control of wire height. Stronger anti-Stokes emission

Potma, Eric Olaf

361

Author's personal copy Forcing technological change: A case of automobile emissions control  

E-print Network

technology development in the US Jaegul Lee a,n , Francisco M. Veloso b,1 , David A. Hounshell c,2 , Edward S their research and development (R&D) processes concerning automobile emissions control technologies amidAuthor's personal copy Forcing technological change: A case of automobile emissions control

362

FUEL FORMULATION EFFECTS ON DIESEL FUEL INJECTION, COMBUSTION, EMISSIONS AND EMISSION CONTROL  

SciTech Connect

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.

Boehman, A; Alam, M; Song, J; Acharya, R; Szybist, J; Zello, V; Miller, K

2003-08-24

363

Atom localization via phase and amplitude control of the driving field  

Microsoft Academic Search

Control of amplitude and phase of the driving field in an atom-field interaction leads towards the strong line narrowing and quenching in the spontaneous emission spectrum. We exploit this fact for the atom localization scheme and achieve a much better spatial resolution in the conditional position probability distribution of the atom. Most importantly the quenching in the spontaneous emission manifests

Fazal Ghafoor; Sajid Qamar; M. Suhail Zubairy

2002-01-01

364

Emission Controls Using Different Temperatures of Combustion Air  

PubMed Central

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

Holub?ík, Michal; Papu?ík, Štefan

2014-01-01

365

Spontaneous fission properties and lifetime systematics  

SciTech Connect

Half-lives for spontaneous fission of nuclides with even and odd numbers of particles are compared with recent theoretical calculations. A summary of odd particle hindrance factors is given. The most recent measurements of kinetic-energy and mass distributions and neutron emission for spontaneous fission of the heaviest nuclides are summarized and discussed. 51 refs., 9 figs.

Hoffman, D.C.

1989-03-01

366

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

Microsoft Academic Search

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

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

1966-01-01

367

Review of spontaneous combustion problems and controls with application to US Coal Mines. Final technical report. [150 references  

Microsoft Academic Search

Expansion of underground coal mining activity in the Western US will increase the risk of spontaneous-combustion-caused mine fires. Such incidents in underground coal mines have, in the past, frequently led to serious financial loss or loss of life. The first part of this report is a state-of-the-art review and describes the mechanism of coal oxidation and its development to open

J. P. L. Bacharach; E. A. C. Chamberlain; D. A. Hall; S. B. Lord; D. J. Steele

1978-01-01

368

Motorcycle emission control demonstration. Final report April--November 1977  

Microsoft Academic Search

The testing of ten motorcycles for exhaust emissions of hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) is described. Emission rates in grams per kilometer are presented for the 1975 Federal Test Procedure and the Highway Fuel Economy Test, as well as in percent or parts per million for several steady-state conditions. The test motorcycles were equipped with

T. L. Ullman; C. T. Hare

1977-01-01

369

COMBUSTION CONTROL OF ORGANIC EMISSIONS FROM MUNICIPAL WASTE COMBUSTORS  

EPA Science Inventory

More than two decades ago, researchers identified benzo(a)pyrene and other organic species in the emissions from incineration of solid waste. Chlorinated dibenzo-p-dioxins and-furans (CDD/CDF) were first detected in municipal waste combustor (MWC) emissions in 1977. Since then, C...

370

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...

371

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...

372

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

PubMed

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

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

2012-01-01

373

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

SciTech Connect

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.

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

2010-05-01

374

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

E-print Network

Nitrogen Isotopic Composition of Coal-Fired Power Plant NOx: Influence of Emission Controls. This manuscript presents the first measurements of the nitrogen isotopic composition of NOx (15 N- NOx) emitted. NOx is produced in EGU boilers either by reaction of nitrogen with oxygen in combustion air ("thermal

Elliott, Emily M.

375

Southern California Edison's (SCE) Research Program for Industrial Volatile Organic Compound (VOC) Emissions Control  

E-print Network

in this program involves the evaluation of portable emission control systems. The systems are sized to process a slipstream of 100 to 300 cfm of solvent laden air (SLA) vented from the industrial processes. A number of different emission control technologie... to storage. Different types and qualit'es of foam are produced from different mixtures of base materials and differen concentrations of foaming agents. Duri g the demonstration, a slipstream of the exhaust was directed to the control equipment...

Sung, R. D.; Cascone, R.; Reese, J.

376

Membrane technology for the control and recovery of vapor emissions from storage tanks  

SciTech Connect

Organic vapor emissions from storage tanks are increasingly subject to control and regulation from both national and local laws. Title 1 of the Clean Air Act Amendments of 1990 require local authorities to control emissions of VOCs. Additional regulations have been imposed at the national level on hazardous air pollutants (HAPs). Membrane separation, commercialized within the last decade for hydrogen recovery and nitrogen generation applications, is now emerging as an attractive method for control of VOC emissions from a variety of sources, including storage tank emissions. MTR`s vapor recovery process combines both membrane separation and condensation, making it suitable for a broad range of applications. Membranes work like filters -- except here the larger vapor molecule goes through the membrane, while the smaller air molecules are retained. The membrane process has many advantages over other control techniques: the vapor is recovered as a liquid rather than destroyed; it is a continuous process not requiring regeneration; high removal efficiencies can be achieved (90--99.99%); variations in feed conditions (air flow, VOC concentration or species) are easily accommodated; and no secondary wastes are produced. The presentation includes a more detailed description of the membrane separation process, and describes several applications of MTR`s VaporSep technology for controlling vapor emissions. The first application is the control of gasoline vapors at service stations. Another application is recovery of various VOCs from storage tank emissions at a solvent recovery facility. The final application if a membrane system to control cyclohexane emissions from a storage tank. This system can operate in two separate modes: a low-flow mode to control emissions due to tank breathing, and a high-flow mode to control emissions from cleaning operations.

Gottschlich, D.; Simmons, V.; Jacobs, M. [Membrane Technology and Research, Inc., Menlo Park, CA (United States)

1995-12-31

377

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

NASA Astrophysics Data System (ADS)

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.

Yuan, Le; Weng, Xiaolong; Deng, Longjiang

2013-01-01

378

Emissions and demonstration of an emission control technology for small two-stroke utility engines.  

PubMed

Small utility engines represent an important contribution to the emissions inventory and have been subjected to increasingly stringent regulations in recent years. For this project, a Tanaka two-stroke engine was tested in its original condition and with a modified fuel/oil injection system. The modified fuel/oil injection system applied to the Tanaka two-stroke engine resulted in significant emissions reductions of approximately 52% for carbon monoxide (CO), 70% for total hydrocarbons (THC), 70% for particulate matter (PM), and 67% for the regulated THC + nitrogen oxides metric. This technology met the California Air Resources Board's 2000 model-year regulations for all pollutants, with the exception of slightly higher PM emissions. Two additional two-stroke engines were tested under a new condition and after at least 100 hr of use to examine the effects of deterioration on in-use, two-stroke engines. For one engine, CO and PM emissions more than tripled after 162 hr of operation in the field, with smaller increases also observed for THC (20%). For the second engine, significant repairs were required throughout the 100 operating hours, which counteracted the effects of the emissions deterioration and resulted in lower CO and THC emissions. PMID:14977321

Welch, William; Durbin, Thomas D

2004-02-01

379

Emission-control effectiveness of a woodstove catalyst and emission-measurement-methods comparison  

SciTech Connect

The paper gives results of measurements of emissions from a prototype catalytic and a generic noncatalytic stove over a range of burn rates. For the catalytic stove, simultaneous EPA Modified Method 5 (MM5) samples were obtained before the catalyst and in the stack. For both stoves, Oregon Method 7 (OM7) and Condar dilution samplers (CDS) were operated simultaneously with the MM5 train at the stack location. Volatile organic samples were obtained by integrated bag sampler at the stack location. Results show a generally predictable correlation between MM5, OM7 and CDS results. Emission rates, based on MM5, were about twice those based on OM7 and CDS. Catalyst emission reduction effectiveness (by MM5) ranged from 72 to 98%. Catalyst inlet emissions appear to be affected by the test sequence: a high burn-rate test produced higher emissions when preceded by a low burn-rate test than when preceded by a high burn-rate test. Volatile organic emissions were about the same at all burn-rates on the catalytic stove and at low burn rates on the noncatalytic stove. At a high burn rate, the noncatalytic stove produced substantially less. All MM5 samples tested positive for polynuclear aromatic hydrocarbons.

McCrillis, R.C.; Merrill, R.G.

1985-01-01

380

Spontaneous and induced emission of XeCl* excimer molecules under pumping of Xe - CCl4 and Ar - Xe - CCl4 gas mixtures with a low CCl4 content by fast electrons and uranium fission fragments  

NASA Astrophysics Data System (ADS)

The spontaneous and induced emission of XeCl* excimer molecules upon excitation of Xe - CCl4 and Ar - Xe - CCl4 gas mixtures with a low CCl4 content by high-energy charged particles [a pulsed high-energy electron beam and products of neutron nuclear reaction 235U(n, f)] has been experimentally studied. The electron energy was 150 keV, and the pump current pulse duration and amplitude were 5 ns and 5 A, respectively. The energy of fission fragments did not exceed 100 MeV, the duration of the neutron pump pulse was 200 ?s, and the specific power contribution to the gas was about 300 W cm-3. Electron beam pumping in a cell 4 cm long with a cavity having an output mirror transmittance of 2.7% gives rise to lasing on the B ? X transition in the XeCl* molecule (? = 308 nm) with a gain ? = 0.0085 cm-1 and fluorescence efficiency ? ? 10%. Pumping by fission fragments in a 250-cm-long cell with a cavity formed by a highly reflecting mirror and a quartz window implements amplified spontaneous emission (ASE) with an output power of 40 - 50 kW sr-1 and a base ASE pulse duration of ~200 ms.

Mis'kevich, A. I.; Guo, J.; Dyuzhov, Yu A.

2013-11-01

381

Spontaneous Emission of a Two-Level Static Atom Coupling with Electromagnetic Vacuum Fluctuations Outside a High-Dimensional Einstein Gauss–Bonnet Black Hole  

NASA Astrophysics Data System (ADS)

Using the generalized formalism of Dalibard, Dupont–Roc and Cohen–Tannoudji we investigate the spontaneous excitation of a static atom interacting with electromagnetic vacuum fluctuations outside an Einstein Gauss–Bonnet black hole in d-dimensions. It shows that spontaneous excitation does not occur in a Boulware vacuum, while exists in an Unruh vacuum and Hartle–Hawking vacuum. As to the total rate of change of the atomic energy, it does not receive the contribution from the coupling constant of the Gauss–Bonnet term at spatial infinity only the dimensional parameter has the contribution to it. Near the event horizon, both the coupling constant and the dimension p contribute to the total rate of change of the atomic energy in all three kinds of vacuum. We discuss the contribution of the coupling constant and dimensional factor to the results in three different kinds of spacetime lastly.

Zhang, Ming; Yang, Zhan-Ying; Yue, Rui-Hong

2014-10-01

382

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

Code of Federal Regulations, 2014 CFR

...organic emissions mass flow rates for the inlet and outlet of the add-on control device using Equation...efficiency of the add-on control device, percent...organic emissions mass flow rate at the inlet(s) to the add-on control device, using...

2014-07-01

383

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

Code of Federal Regulations, 2012 CFR

...organic emissions mass flow rates for the inlet and outlet of the add-on control device using Equation...efficiency of the add-on control device, percent...organic emissions mass flow rate at the inlet(s) to the add-on control device, using...

2012-07-01

384

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

Code of Federal Regulations, 2013 CFR

...organic emissions mass flow rates for the inlet and outlet of the add-on control device using Equation...efficiency of the add-on control device, percent...organic emissions mass flow rate at the inlet(s) to the add-on control device, using...

2013-07-01

385

Diesel Emission Control -- Sulfur Effects (DECSE) Program; Phase I Interim Data Report No. 1  

SciTech Connect

The Diesel Emission Control-Sulfur Effects (DECSE) is a joint government/industry program to determine the impact of diesel fuel sulfur levels on emission control systems whose use could lower emissions of nitrogen oxides (NO{sub x}) and particulate matter (PM) from on-highway trucks in the 2002--2004 model years. Phase 1 of the program was developed with the following objectives in mind: (1) evaluate the effects of varying the level of sulfur content in the fuel on the emission reduction performance of four emission control technologies; and (2) measure and compare the effects of up to 250 hours of aging on selected devices for multiple levels of fuel sulfur content. This interim data report summarizes results as of August, 1999, on the status of the test programs being conducted on three technologies: lean-NO{sub x} catalysts, diesel particulate filters and diesel oxidation catalysts.

DOE; ORNL; NREL; EMA; MECA

1999-08-15

386

Parameters controlling nitric oxide emissions from gas turbine combustors  

NASA Technical Reports Server (NTRS)

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.

Heywood, J. B.; Mikus, T.

1973-01-01

387

40 CFR 63.4362 - How do I determine the add-on control device emission destruction or removal efficiency?  

Code of Federal Regulations, 2011 CFR

...2009-07-01 true How do I determine the add-on control device emission destruction...Requirements § 63.4362 How do I determine the add-on control device emission destruction...methods in this section to determine the add-on control device emission...

2011-07-01

388

40 CFR 63.4965 - How do I determine the add-on control device emission destruction or removal efficiency?  

Code of Federal Regulations, 2011 CFR

...2009-07-01 true How do I determine the add-on control device emission destruction...Compliance Requirements for the Emission Rate with Add-on Controls Option § 63.4965 How do I determine the add-on control device emission...

2011-07-01

389

40 CFR 63.4566 - How do I determine the add-on control device emission destruction or removal efficiency?  

Code of Federal Regulations, 2011 CFR

...2009-07-01 true How do I determine the add-on control device emission destruction...Compliance Requirements for the Emission Rate with Add-on Controls Option § 63.4566 How do I determine the add-on control device emission...

2011-07-01

390

40 CFR 63.3545 - How do I determine the add-on control device emission destruction or removal efficiency?  

Code of Federal Regulations, 2011 CFR

...2009-07-01 true How do I determine the add-on control device emission destruction...Compliance Requirements for the Emission Rate with Add-on Controls Option § 63.3545 How do I determine the add-on control device emission...

2011-07-01

391

40 CFR 63.9323 - How do I determine the add-on control device emission destruction or removal efficiency?  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false How do I determine the add-on control device emission destruction...Requirements § 63.9323 How do I determine the add-on control device emission destruction...methods in this section to determine the add-on control device emission...

2011-07-01

392

40 CFR 63.4766 - How do I determine the add-on control device emission destruction or removal efficiency?  

Code of Federal Regulations, 2011 CFR

...2009-07-01 true How do I determine the add-on control device emission destruction...Compliance Requirements for the Emission Rate with Add-on Controls Option § 63.4766 How do I determine the add-on control device emission...

2011-07-01

393

40 CFR 63.4166 - How do I determine the add-on control device emission destruction or removal efficiency?  

Code of Federal Regulations, 2011 CFR

...2009-07-01 true How do I determine the add-on control device emission destruction...Compliance Requirements for the Emission Rate with Add-on Controls Option § 63.4166 How do I determine the add-on control device emission...

2011-07-01

394

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...

395

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...

396

CONTROL OF MERCURY EMISSIONS FROM COAL-FIRED ELECTRIC UTILITY BOILERS: INTERIM REPORT  

EPA Science Inventory

The report provides additional information on mercury (Hg) emissions control following the release of "Study of Hazardous Air Pollutant Emissions from Electric Utility Steam Generating Units--Final Report to Congress" in February 1998. Chapters 1-3 describe EPA's December 2000 de...

397

ASSESSMENT OF STYRENE EMISSION CONTROLS FOR FRP/C AND BOAT BUILDING INDUSTRIES  

EPA Science Inventory

The report gives results of an evaluation of several conventional and novel emission control technologies that have been used or could be used to treat styrene emissions from open molding processes in fiberglass-reinforced plastics/composites (FRP/C) and fiberglass boat building ...

398

Control of Atmospheric Emissions in the Wood Pulping Industry, Volume 3.  

ERIC Educational Resources Information Center

Volume 3 contains chapters 9 through 13 of the final report on the control of atmospheric emissions in the wood pulping industry. These chapters deal with the following topics: sampling and analytical techniques; on-going research related to reduction of emissions; research and development recommendations; current industry investment and operating…

Hendrickson, E. R.; And Others

399

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...

400

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

E-print Network

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

Resasco, Daniel

401

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...

402

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...

403

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

Federal Register 2010, 2011, 2012, 2013, 2014

...State of Missouri; Control of Sulfur Emissions From Stationary Boilers AGENCY: Environmental Protection Agency (EPA). ACTION...a precursor pollutant to PM 2.5 ), from industrial boilers. EPA is approving this revision because it strengthens...

2013-01-25

404

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...

405

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT, HONEYWELL POWER SYSTEMS, INC. PARALLON 75 KW TURBOGENERATOR WITH CO EMISSIONS CONTROL  

EPA Science Inventory

The Greenhouse Gas Technology Center (GHG Center), one of six verification organizations under the Environmental Technology Verification (ETV) program, evaluated the performance of the Parallon 75 kW Turbogenerator (Turbogenerator) with carbon monoxide (CO) emissions control syst...

406

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...

407

Low emissivity and solar control coatings on architectural glass  

Microsoft Academic Search

Methods of depositing thin films on glass using the vacuum coating technic were developed to impede the transfer of heat through glass thus reducing the energy costs for room heating or air conditioning. Heat reflecting so-called low emissivity coatings permit a maximum amount of daylight to pass through, but then block the heat that is generated when light strikes an

W. D. Dachselt; W. D. Munz; M. Scherer

1982-01-01

408

Intertemporal Permit Trading for the Control of Greenhouse Gas Emissions  

Microsoft Academic Search

This paper integrates two themes in the intertemporal permit literature through the con- struction of an intertemporal banking system for a pollutant that creates both stock and flow damages. A permit banking system for the special case of a pollutant that only causes stock damages is also developed. This latter, simpler case corresponds roughly to the greenhouse gas emission reduction

PAUL LEIBY; JONATHAN RUBIN

2008-01-01

409

40 CFR 266.104 - Standards to control organic emissions.  

Code of Federal Regulations, 2012 CFR

...waste feed considering the results of waste analyses submitted with part B of the permit...Multiply the emission rates of CDD/CDF congeners with a toxicity equivalence...testing, and where applicable, CDD/CDF testing under paragraph (e) of this...

2012-07-01

410

40 CFR 266.104 - Standards to control organic emissions.  

Code of Federal Regulations, 2010 CFR

...waste feed considering the results of waste analyses submitted with part B of the permit...Multiply the emission rates of CDD/CDF congeners with a toxicity equivalence...testing, and where applicable, CDD/CDF testing under paragraph (e) of this...

2010-07-01

411

40 CFR 266.104 - Standards to control organic emissions.  

Code of Federal Regulations, 2011 CFR

...waste feed considering the results of waste analyses submitted with part B of the permit...Multiply the emission rates of CDD/CDF congeners with a toxicity equivalence...testing, and where applicable, CDD/CDF testing under paragraph (e) of this...

2011-07-01

412

40 CFR 266.104 - Standards to control organic emissions.  

Code of Federal Regulations, 2013 CFR

...waste feed considering the results of waste analyses submitted with part B of the permit...Multiply the emission rates of CDD/CDF congeners with a toxicity equivalence...testing, and where applicable, CDD/CDF testing under paragraph (e) of this...

2013-07-01

413

Fast-regenerable sulfur dioxide adsorbents for diesel engine emission control  

SciTech Connect

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.

Li, Liyu [Richland, WA; King, David L [Richland, WA

2011-03-15

414

EMISSION CONTROL EFFECTIVENESS OF A WOODSTOVE CATALYST AND EMISSION MEASUREMENT METHODS COMPARISON  

EPA Science Inventory

The paper gives results of measurements of emissions from a prototype catalytic and a generic noncatalytic stove over a range of burnrates. For the catalytic stove, simultaneous EPA Modified Method 5 (MM5) samples were obtained before the catalyst and in the stack. For both stove...

415

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

SciTech Connect

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.

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

2011-12-12

416

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

NASA Astrophysics Data System (ADS)

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.

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

417

Controlling SO2 emissions in the roasting of gold concentrate  

NASA Astrophysics Data System (ADS)

Acid pressure oxidation is generally believed to be the most effective pretreatment for refractory sulfide gold ores and concentrates, although it is ineffective for some ores. For such ores and concentrates (usually those containing both carbonaceous and sulfide materials), roasting remains the most effective pretreatment before cyanidation. However, the serious environmental damage that could result from the emission of SO2 and As2O3 makes roasting an unattractive pretreatment step. In an effort to develop a technique having lower SO2 emissions, a lime agglomeration roast (LAR) pretreatment process was investigated. The technique involves the agglomeration of calcium-based SO2 sorbent with the refractory ore or concentrate before roasting. The results of the LAR pretreatment followed by cyanidation indicate that up to 95 percent of the sulfur dioxide can be captured and more than 90 percent gold extraction can be achieved.

Nyavor, Kafui; Egiebor, Nosa O.

1991-12-01

418

STANDARDS CONTROLLING AIR EMISSIONS FOR THE SOIL DESICCATION PILOT TEST  

Microsoft Academic Search

This air emissions document supports implementation of the Treatability Test Plan for Soil Desiccation as outlined in the Deep Vadose Zone Treatability Test Plan for the Hanford Central Plateau (DOE\\/RL-2007-56). Treatability testing supports evaluation of remedial technologies for technetium-99 (Tc-99) contamination in the vadose zone at sites such as the BC Cribs and Trenches. Soil desiccation has been selected as

BENECKE MW

2010-01-01

419

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

SciTech Connect

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.

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

420

Integrated emissions control system for residential CWS furnace. Final report, September 20, 1989--March 20, 1993  

SciTech Connect

One of the major obstacles to the successful development and commercialization of a coal-fired residential furnace is the need for a reliable, cost-effective emission control system. Tecogen is developing a novel, integrated control system to control NO{sub x}SO{sub 2}, and particulate emissions. At the heart of this system is a unique emissions control reactor for the control of SO{sub 2}. This reactor provides high sorbent particle residence time within the reactor while doing so in a very compact geometry. Final cleanup of any fine particulates exiting the reactor including respirable-sized particulates, is completed with the use of high efficiency bag filters. Under a previous contract with PETC (Contract No. DE-AC22-87PC79650), Tecogen developed a residential-scale Coal Water Slurry (CWS) combustor to control NO{sub x}emission. This combustor makes use of centrifugal forces, set up by a predominantly tangential flow field, to separate and confine larger unburned coal particles in the furnace upper chamber. Various partitions are used to retard the axial, downward flow of these particles, and thus maximize their residence time in the hottest section of the combustor. By operating this combustor under staged conditions, the local stoichiometry in the primary zone can be controlled in such a manner as to minimize NO{sub x} emission.

Breault, R.W.; McLarnon, C.

1993-03-01

421

Volatile organic compounds (VOCs) emission characteristics and control strategies for a petrochemical industrial area in middle Taiwan  

Microsoft Academic Search

This study investigated VOC emissions from the largest petrochemical industrial district in Taiwan and recommended some control measures to reduce VOC emissions. In addition to the petrochemical industry, the district encompasses a chemical and fiber industry, a plastics industry and a harbor, which together produce more than 95% of the VOC emissions in the area. The sequence of VOC emission

Chia-Hsien Yen; Jao-Jia Horng

2009-01-01

422

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

PubMed

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

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

2015-02-18

423

To what extent do smokers make spontaneous quit attempts and what are the implications for smoking cessation maintenance? Findings from the International Tobacco Control Four country survey  

PubMed Central

Aim: To assess the extent to which quit attempts are spontaneous and to evaluate if this is a determinant of smoking cessation maintenance, with better control for memory effects. Methods: We use data from 3,022 smokers who made quit attempts between Waves 4 and 5 and/or Waves 5 and 6 of the International Tobacco Control Four country survey. Outcomes (quitting for 6 months) were confirmed at the next wave for cases where the attempt began within the previous 6 months. We assessed the length of delay between the decision to quit and implementation and whether the attempt followed a “spur-of-the-moment” decision or some serious prior consideration. Outcomes were modeled using generalized estimating equations. Results: Prior consideration of quitting was unrelated to the outcome, but there were complex relationships for the delay between choosing a quit day and implementation. Those who reported quitting on the day they decided and those who delayed for 1 week or more had comparable rates of 6-month abstinence. Delaying for 1–6 days was associated with a greater relapse rate than those who quit on the day, although this effect became nonsignificant in multivariate analyses. Conclusions: Quitting is on most smokers’ minds regularly and most attempts are not preceded by a long lead in period following the decision to try. Neither prior consideration nor delay between the decision to quit and implementation was clearly related to outcomes. Previous findings of greater success for spontaneous quit attempts may be because they conflate setting a date in advance with planning and also perhaps some differential memory effects. PMID:20889481

Cooper, Jae; Yong, Hua-Hie; McNeill, Ann; Murray, Rachael L.; O’Connor, Richard J.; Cummings, K. Michael

2010-01-01

424

Microfabricated Chemical Sensors for Safety and Emission Control Applications  

NASA Technical Reports Server (NTRS)

Chemical sensor technology is being developed for leak detection, emission monitoring, and fire safety applications. The development of these sensors is based on progress in two types of technology: 1) Micromachining and microfabrication (MicroElectroMechanical Systems (MEMS)-based) technology to fabricate miniaturized sensors. 2) The development of high temperature semiconductors, especially silicon carbide. Using these technologies, sensors to measure hydrogen, hydrocarbons, nitrogen oxides, carbon monoxide, oxygen, and carbon dioxide are being developed. A description is given of each sensor type and its present stage of development. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

Hunter, G. W.; Neudeck, P. G.; Chen, L.-Y.; Knight, D.; Liu, C. C.; Wu, Q. H.

1998-01-01

425

Study of Lean NOx Technology for Diesel Emission Control  

SciTech Connect

Diesel engines because of their reliability and efficiency are a popular mobile source. The diesel engine operates at higher compression ratios and with leaner fuel mixtures and produces lower carbon monoxide and hydrocarbon emissions. The oxygen-rich environment leads to higher nitrogen oxides in the form of NO. Catalysts selectively promoting the reduction of NOx by HCs in a lean environment have been termed lean NOx catalyst ''LNC''. The two groups that have shown most promise are, Copper exchanged zeolite Cu/ZSM5, and Platinum on alumina Pt/Al2O3.

Mital, R.

2000-08-20

426

Effectiveness of Diesel Oxidation Catalyst in Reducing HC and CO Emissions from Reactivity Controlled Compression Ignition  

SciTech Connect

Reactivity Controlled Compression Ignition (RCCI) has been shown to allow for diesel-like or better brake thermal efficiency with significant reductions in nitrogen oxide (NOX) particulate matter (PM) emissions. Hydrocarbon (HC) and carbon monoxide (CO) emission levels, on the other hand, are similar to those of port fuel injected gasoline engines. The higher HC and CO emissions combined with the lower exhaust temperatures with RCCI operation present a challenge for current exhaust aftertreatments. The reduction of HC and CO emissions in a lean environment is typically achieved with an oxidation catalyst. In this work, several diesel oxidation catalysts (DOC) with different precious metal loadings were evaluated for effectiveness to control HC and CO emissions from RCCI combustion in a light-duty multi-cylinder engine operating on gasoline and diesel fuels. Each catalyst was evaluated in a steady-state engine operation with temperatures ranging from 160 to 260 C. A shift to a higher light-off temperature was observed during the RCCI operation. In addition to the steady-state experiments, the performances of the DOCs were evaluated during multi-mode engine operation by switching from diesel-like combustion at higher exhaust temperature and low HC/CO emissions to RCCI combustion at lower temperature and higher HC/CO emissions. High CO and HC emissions from RCCI generated an exotherm keeping the catalyst above the light-off temperature.

Prikhodko, Vitaly Y [ORNL; Curran, Scott [ORNL; Parks, II, James E [ORNL; Wagner, Robert M [ORNL

2013-01-01

427

Real-time polarization mode dispersion monitoring system for a multiple-erbium-doped fiber amplifier, dense wavelength division multiplexing optical fiber transmission by amplified spontaneous emission modulation and acousto-optic tunable fiber scanning techniques.  

PubMed

Without interruption or affecting the transmission of ordinary payload channels, we propose a real time polarization mode dispersion (PMD) monitoring system for long-haul, multiple erbium-doped fiber amplifier (EDFA), dense wavelength division multiplexing (DWDM) optical fiber transmission using modulated amplified spontaneous emission (ASE) of one of the EDFAs as the supervisory (SV) signal source. An acousto-optic tunable filter (AOTF) at the receiver side is adopted to scan the spectrum of the transmitted ASE SV signal. Using the fixed-analyzer method, PMDs of different wavelength bands that range from 1545 to 1580 nm of a DWDM fiber-optic communication system can be found by adaptively changing the radio frequency of the AOTF. The resolution and the measuring range of the proposed monitoring system can be significantly improved by cascading the AOTFs at the receiver side. PMID:19252622

Tseng, Bao-Jang; Tarn, Chen-Wen

2009-03-01

428

Control of GHG emission at the microbial community level.  

PubMed

All organic material eventually is decomposed by microorganisms, and considerable amounts of C and N end up as gaseous metabolites. The emissions of greenhouse relevant gases like carbon dioxide, methane and nitrous oxides largely depend on physico-chemical conditions like substrate quality or the redox potential of the habitat. Manipulating these conditions has a great potential for reducing greenhouse gas emissions. Such options are known from farm and waste management, as well as from wastewater treatment. In this paper examples are given how greenhouse gas production might be reduced by regulating microbial processes. Biogas production from manure, organic wastes, and landfills are given as examples how methanisation may be used to save fossil fuel. Methane oxidation, on the other hand, might alleviate the problem of methane already produced, or the conversion of aerobic wastewater treatment to anaerobic nitrogen elimination through the anaerobic ammonium oxidation process might reduce N2O release to the atmosphere. Changing the diet of ruminants, altering soil water potentials or a change of waste collection systems are other measures that affect microbial activities and that might contribute to a reduction of carbon dioxide equivalents being emitted to the atmosphere. PMID:18053703

Insam, H; Wett, B

2008-01-01

429

Isoprenoid emission of oak species typical for the Mediterranean area: Source strength and controlling variables  

NASA Astrophysics Data System (ADS)

Measurements of isoprenoid emission on five Mediterranean oak species in the field revealed that Quercus frainetto, Quercus petraea and Quercus pubescens are strong emitters of isoprene. In contrast Quercus cerris and Quercus suber emitted no significant amounts of isoprene and monoterpenes. For Q. pubenscens and Q. frainetto median emission factors of 16.68 nmol m -2 s -1 (86.06 ?g g -1 dw h -1) and 30.72 nmol m -2 s -1 (133.95 ?g g -1 dw h -1 were calculated, respectively. The 25 to 75 percentiles span of the emission factor data sets ranged from - 53% to + 56% of the median values. Light and temperature are the main controlling factors for isoprene emission. The influence of other environmental and plant physiological parameters on the isoprene emission is discussed. The "Guenther" emission algorithm is able to predict the daily maximum of the isoprene emission within the plant specific uncertainty range. However, the morning increase and the afternoon drop in the isoprene emission is not well parameterized. On the basis of process oriented models for the synthesis of isoprene in plants, a further reduction in the uncertainty may be achieved resulting in a more reliable prediction of short-time variation in isoprene emission.

Steinbrecher, Rainer; Hauff, Karin; Rabong, Richard; Steinbrecher, Jutta

430

New experimental device for infrared spectral directional emissivity measurements in a controlled environment  

NASA Astrophysics Data System (ADS)

A new experimental device for infrared spectral directional emissivity measurements in a controlled atmosphere is presented. The sample holder, which permits to measure spectral directional emissivity up to 1050K, is placed inside a stainless steel sample chamber that can be evacuated or filled with different gases. The signal detection is carried out by means of a Fourier transform infrared spectrometer. The experimental results focus on the capability of the device to perform emissivity measurements as a function of temperature, emission angle, and in situ surface state evolution. A careful study of the sample temperature homogeneity and the measurement method has been done, including the background radiation, the apparatus response function, and temperature differences between the sample and the blackbody radiator. As a consequence, a compact expression for the sample emissivity that generalizes those previously obtained for the direct radiometric measurement method is found. The error assessment shows that the main contribution to the emissivity uncertainty is related to the sample temperature. The overall uncertainty at intermediate temperature is estimated to be around 3% at short wavelengths. Emissivity measurements of Armco iron were used in order to check the accuracy of the experimental device. The experimental results show an excellent fit with direct emissivity data accessible in the literature, as well as with the theoretical emissivity obtained from the Hagen-Rubens relation.

del Campo, Leire; Pérez-Sáez, Raúl B.; Esquisabel, Xabier; Fernández, Ignacio; Tello, Manuel J.

2006-11-01

431

ESTABLISHING THE LINK BETWEEN AMMONIA EMISSION CONTROL AND MEASUREMENTS OF REDUCED NITROGEN  

E-print Network

ESTABLISHING THE LINK BETWEEN AMMONIA EMISSION CONTROL AND MEASUREMENTS OF REDUCED NITROGEN, Slovakia; 10 Swiss Agency for the Environment, Forest and Landscape (SAEFL), Air Pollution Control Division for some time that the atmospheric transport and deposition of reduced nitrogen (NHx), either as ammonia

Aneja, Viney P.

432

EFFECTIVENESS OF A HIGH-PRESSURE, WATER FOGGING SYSTEM IN CONTROLLING DUST EMISSIONS AT GRAIN RECEIVING  

Technology Transfer Automated Retrieval System (TEKTRAN)

Grain dust at the receiving area is a fire hazard, a health concern, and a sanitation problem and should be controlled. The effectiveness of a high-pressure, water-fog system in controlling grain dust emissions was evaluated with corn and wheat while spouting 2.1 m3 (60 bu) of grain into a test c...

433

CONTROL OF HYDROCARBON EMISSIONS FROM COTTON AND SYNTHETIC TEXTILE FINISHING PLANTS  

EPA Science Inventory

The report gives results of an evaluation of the applicability and economics of emissions control technologies for the abatement of volatile organic compounds emanating from cotton and synthetic textile finishing plants. A survey of the state-of-the-art and control technologies d...

434

COAL CONVERSION CONTROL TECHNOLOGY. VOLUME II. GASEOUS EMISSIONS; SOLID WASTES  

EPA Science Inventory

This volume is the product of an information-gathering effort relating to coal conversion process streams. Available and developing control technology has been evaluated in view of the requirements of present and proposed federal, state, regional, and international environmental ...

435

Heavy-Duty Emissions Control: Plasma-Facilitated vs Reformer-Assisted Lean NOx Catalysis  

SciTech Connect

Progress has been made in the control of combustion processes to limit the formation of environmentally harmful species, but lean burn vehicles, such as those powered by diesel engines used for the majority of commercial trucking and off-road applications, remain a major source of nitrogen oxides (NOx) and particulate matter (PM) emissions. Tighter control of the combustion process coupled with exhaust gas recirculation has brought emissions in line with 2004 targets worldwide. Additional modifications to the engine control system, somewhat limited NOx control, and PM filters will likely allow the 2007 limits to be met for the on-highway regulations for heavy-duty engines in the United States. Concern arises when the NOx emission limit of 0.2 g/bhphr set for the year 2010 is considered.

(1)Aardahl, C; (1)Rozmiarek, R; (1)Rappe, K; (1)Mendoza, D (2)Park, P

2003-08-24

436

DEMONSTRATION OF AN ADVANCED INTEGRATED CONTROL SYSTEM FOR SIMULTANEOUS EMISSIONS REDUCTION  

SciTech Connect

The primary objective of the project titled ''Demonstration of an Advanced Integrated Control System for Simultaneous Emissions Reduction'' was to demonstrate at proof-of-concept scale the use of an online software package, the ''Plant Environmental and Cost Optimization System'' (PECOS), to optimize the operation of coal-fired power plants by economically controlling all emissions simultaneously. It combines physical models, neural networks, and fuzzy logic control to provide both optimal least-cost boiler setpoints to the boiler operators in the control room, as well as optimal coal blending recommendations designed to reduce fuel costs and fuel-related derates. The goal of the project was to demonstrate that use of PECOS would enable coal-fired power plants to make more economic use of U.S. coals while reducing emissions.

Suzanne Shea; Randhir Sehgal; Ilga Celmins; Andrew Maxson

2002-02-01

437

Diesel Emission Control -- Sulfur Effects (DECSE) Program; Phase I Interim Date Report No. 3: Diesel Fuel Sulfur Effects on Particulate Matter Emissions  

SciTech Connect

The Diesel Emission Control-Sulfur Effects (DECSE) is a joint government/industry program to determine the impact of diesel fuel sulfur levels on emission control systems whose use could lower emissions of nitrogen oxides (NO{sub x}) and particulate matter (PM) from on-highway trucks in the 2002--2004 model years. Phase 1 of the program was developed with the following objectives in mind: (1) evaluate the effects of varying the level of sulfur content in the fuel on the emission reduction performance of four emission control technologies; and (2) measure and compare the effects of up to 250 hours of aging on selected devices for multiple levels of fuel sulfur content. This interim report covers the effects of diesel fuel sulfur level on particulate matter emissions for four technologies.

DOE; ORNL; NREL; EMA; MECA

1999-11-15

438

Diesel Exhaust Emissions Control for Light-Duty Vehicles  

SciTech Connect

The objective of this paper is to present the results of diesel exhaust aftertreatment testing and analysis done under the FreedomCAR program. Nitrogen Oxides (NOx) adsorber technology was selected based on a previous investigation of various NOx aftertreatment technologies including non-thermal plasma, NOx adsorber and active lean NOx. Particulate Matter (PM) emissions were addressed by developing a catalyzed particulate filter. After various iterations of the catalyst formulation, the aftertreatment components were integrated and optimized for a light duty vehicle application. This compact exhaust aftertreatment system is dual leg and consists of a sulfur trap, NOx adsorbers, and catalyzed particulate filters (CPF). During regeneration, supplementary ARCO ECD low-sulfur diesel fuel is injected upstream of the adsorber and CPF in the exhaust. Steady state and transient emission test results with and without the exhaust aftertreatment system (EAS) are presented. Results of soot filter regeneration by injecting low-sulfur diesel fuel and slip of unregulated emissions, such as NH3, are discussed. Effects of adsorber size and bypass strategy on NOx conversion efficiency and fuel economy penalty are also presented in this paper. The results indicate that if the supplementary fuel injection is optimized, NH3 slip is negligible. During the FTP cycle, injection of low sulfur diesel fuel can create temperature exotherms high enough to regenerate a loaded CPF. With the optimized NOx adsorber regeneration strategies the fuel injection penalty can be reduced by 40 to 50%. Results for various other issues like low temperature light off, reductant optimization, exhaust sulfur management, system integration and design trade-off, are also presented and discussed in this paper. (SAE Paper SAE-2003-01-0041 © 2003 SAE International. This paper is published on this website with permission from SAE International. As a user of this website, you are permitted to view this paper on-line, download this pdf file and print one copy of this paper at no cost for your use only. The downloaded pdf file and printout of this SAE paper may not be copied, distributed or forwarded to others or for the use of others.)

Mital, R.; Li, J.; Huang, S. C.; Stroia, B. J.; Yu, R. C. (Cummins, Inc.); Anderson, J.A. (Argonne National Laboratory); Howden, Kenneth C. (U.S. Department of Energy)

2003-03-01

439

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

NASA Astrophysics Data System (ADS)

Emissions of particulate matter (PM) from shipping contribute significantly to the anthropogenic burden of PM. The environmental effects of PM from shipping include negative impact on human health through increased concentrations of particles in many coastal areas and harbour cities and the climate impact. The PM emitted by ship engines consists of organic carbon (OC), elemental or black carbon (EC/BC), sulphate, inorganic compounds containing V, Ni, Ca, Zn and other metals and associated water. The chemical composition and physical properties of PM vary with type of fuel burned, type of engine and engine operation mode. While primary PM emissions of species like V, Ni and Ca are supposed to be determined by composition of fuel and lubricant oil, emissions of particulate OC, EC and sulphate are affected both by fuel quality and by operation mode of the engine. In this paper a number of parameters describing emission factors (EFs) of gases and of particulate matter from ship engines were investigated during 2 on-board measurement campaigns for 3 different engines and 3 different types of fuels. The measured EFs for PM mass were in the range 0.3 to 2.7 g/kg-fuel with lowest values for emissions from combustion of marine gas oil (MGO) and the highest for heavy fuel oil (HFO). Emission factors for particle numbers EF(PN) in the range 5 × 1015-1 × 1017 #/kg-fuel were found, the number concentration was dominated by particles in the ultrafine mode and ca. 2/3 of particles were non-volatile. The PM mass was dominated by particles in accumulation mode. Main metal elements in case of HFO exhaust PM were V, Ni, Fe, Ca and Zn, in case of MGO Ca, Zn and P. V and Ni were typical tracers of HFO while Ca, Zn and P are tracers of the lubricant oil. EC makes up 10-38% of the PM mass, there were not found large differences between HFO and MGO fuels. EC and ash elements make up 23-40% of the PM mass. Organic matter makes up 25-60% of the PM. The measured EF(OC) were 0.59 ± 0.15 g/kg-fuel for HFO and 0.22 ± 0.01 g/kg-fuel for MGO. The measured EF(SO42-) were low, ca. 100-200 mg/kg-fuel for HFO with 1% fuel sulphur content (FSC), 70-85 mg/kg-fuel for HFO with 0.5% FSC and 3-6 mg/kg-fuel for MGO. This corresponds to 0.2-0.7% and 0.01-0.02% of fuel S converted to PM sulphate for HFO and MGO, respectively. The (scanning) transmission electron microscopy (TEM and STEM) images of the collected PM have shown three different types of particles: (1) soot composed mainly of C, O, sometimes N, and with traces of Si, S, V, Ca and Ni; (2) char and char-mineral particles composed of C, O, Ca and S (sometimes Si and Al) with traces of V and Ni and sometimes P and (3) amorphous, probably organic particles containing sulphur and some vanadium. The maps of elements obtained from STEM showed heterogeneous composition of primary soot particles with respect to the trace metals and sulphur. Composition of the char-mineral particles indicates that species like CaSO4, CaO and/or CaCO3, SiO2 and/or Al2SiO5, V2O5 and Fe3O4 may be present; the last two were also confirmed by analyses of FTIR spectra of the PM samples. The TPO of PM from the ship exhaust samples showed higher soot oxidation reactivity compared to automotive diesel soot, PM from the HFO exhaust is more reactive than PM from the MGO exhaust. This higher oxidation reactivity could be explained by high content of catalytically active contaminants; in particular in the HFO exhaust PM for which the energy-dispersive X-ray spectroscopy (EDXRF) analyses showed high content of V, Ni and S. Oxidative potential measured as a rate of consumption 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/?g-PM, quite similar to oxidative potentials of PM collected in urban and traffic sites. The data obtained during the experiments add information on emission factors for both gaseous and PM-bound compounds from ship engines using different fuels and under different engine load conditions. Observed variability of t

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.

2013-04-01

440

STANDARDS CONTROLLING AIR EMISSIONS FOR THE SOIL DESICCATION PILOT TEST  

SciTech Connect

This air emissions document supports implementation of the Treatability Test Plan for Soil Desiccation as outlined in the Deep Vadose Zone Treatability Test Plan for the Hanford Central Plateau (DOE/RL-2007-56). Treatability testing supports evaluation of remedial technologies for technetium-99 (Tc-99) contamination in the vadose zone at sites such as the BC Cribs and Trenches. Soil desiccation has been selected as the first technology for testing because it has been recommended as a promising technology in previous Hanford Site technology evaluations and because testing of soil desiccation will provide useful information to enhance evaluation of other technologies, in particular gas-phase remediation technologies. A soil desiccation pilot test (SDPT) will evaluate the desiccation process (e.g., how the targeted interval is dried) and the long-term performance for mitigation of contaminant transport. The SDPT will dry out a moist zone contaminated by Tc-99 and nitrate that has been detected at Well 299-E13-62 (Borehole C5923). This air emissions document applies to the activities to be completed to conduct the SDPT in the 200-BC-1 operable unit located in the 200 East Area of the Hanford Site. Well 299-E13-62 is planned to be used as an injection well. This well is located between and approximately equidistant from cribs 216-B-16, 216-B-17, 216-B-18. and 216-B-19. Nitrogen gas will be pumped at approximately 300 ft{sup 3}/min into the 299-EI3-62 injection well, located approximately 12 m (39 ft) away from extraction well 299-EI3-65. The soil gas extraction rate will be approximately 150 ft{sup 3}/min. The SDPT will be conducted continuously over a period of approximately six months. The purpose of the test is to evaluate soil desiccation as a potential remedy for protecting groundwater. A conceptual depiction is provided in Figure 1. The soil desiccation process will physically dry, or evaporate, some of the water from the moist zone of interest. As such, it is expected that Tc-99 and nitrate will remain with the water residual that is not removed, or remain as a salt bound to the soil particles. In addition, the SDPT will be conducted at lower extraction velocities to preclude pore water entrainment and thus, the extracted air effluent should be free of the contaminant residual present in the targeted moist zone. However, to conservatively bound the planned activity for potential radionuclide air emissions, it is assumed, hypothetically, that the Tc-99 does not remain in the zone of interest, but that it instead travels with the evaporated moisture to the extraction well and to the test equipment at the land surface. Thus, a release potential would exist from the planned point source (powered exhaust) for Tc-99 in the extracted moist air. In this hypothetical bounding case there would also be a potential for very minor fugitive emissions to occur due to nitrogen injection into the soil. The maximum value for Tc-99, measured in the contaminated moist zone, is used in calculating the release potential described in Section 2.3. The desiccation mechanism will be evaporation. Nitrate is neither a criteria pollutant nor a toxic air pollutant. It would remain nitrate as a salt adhered to sand and silt grains or as nitrate dissolved in the pore water. Nitrogen, an inert gas, will be injected into the ground during the test. Tracer gasses will also be injected near the beginning, middle, and the end of the test. The tracer gasses are sulfur hexafluoride, trichlorofluoromethane, and difluoromethane.

BENECKE MW

2010-09-08

441

Laser method of acoustical emission control from vibrating surfaces  

NASA Astrophysics Data System (ADS)

For limitation of the noise in environment, the necessity occurs of determining and location of sources of sounds emitted from surfaces of many machines and devices, assuring in effect the possibility of suitable constructional changes implementation, targeted at decreasing of their nuisance. In the paper, the results of tests and calculations are presented for plane surface sources emitting acoustic waves. The tests were realized with the use of scanning laser vibrometer which enabled remote registration and the spectral analysis of the surfaces vibrations. The known hybrid digital method developed for determination of sound wave emission from such surfaces divided into small finite elements was slightly modified by distinguishing the phase correlations between such vibrating elements. The final method being developed may find use in wide range of applications for different forms of vibrations of plane surfaces.

Motyka, Zbigniew

2013-01-01

442

Control of initiation, rate, and routing of spontaneous capillary-driven flow of liquid droplets through microfluidic channels on SlipChip  

PubMed Central

This paper describes the use of capillary pressure to initiate and control the rate of spontaneous liquid-liquid flow through microfluidic channels. In contrast to flow driven by external pressure, flow driven by capillary pressure is dominated by interfacial phenomena and is exquisitely sensitive to the chemical composition and geometry of the fluids and channels. A step-wise change in capillary force was initiated on a hydrophobic SlipChip by slipping a shallow channel containing an aqueous droplet into contact with a slightly deeper channel filled with immiscible oil. This action induced spontaneous flow of the droplet into the deeper channel. A model predicting the rate of spontaneous flow was developed based on the balance of net capillary force with viscous flow resistance, using as inputs the liquid-liquid surface tension, the advancing and receding contact angles at the three-phase aqueous-oil-surface contact line, and the geometry of the devices. The impact of contact angle hysteresis, the presence or absence of a lubricating oil layer, and adsorption of surface-active compounds at liquid-liquid or liquid-solid interfaces were quantified. Two regimes of flow spanning a 104-fold range of flow rates were obtained and modeled quantitatively, with faster (mm/s) flow obtained when oil could escape through connected channels as it was displaced by flowing aqueous solution, and slower (micrometer/s) flow obtained when oil escape was mostly restricted to a ?m-scale gap between the plates of the SlipChip (“dead-end flow”). Rupture of the lubricating oil layer (reminiscent of a Cassie-Wenzel transition) was proposed as a cause of discrepancy between the model and the experiment. Both dilute salt solutions and complex biological solutions such as human blood plasma could be flowed using this approach. We anticipate that flow driven by capillary pressure will be useful for design and operation of flow in microfluidic applications that do not require external power, valves, or pumps, including on SlipChip and other droplet- or plug-based microfluidic devices. In addition, this approach may be used as a sensitive method of evaluating interfacial tension, contact angles and wetting phenomena on chip. PMID:22233156

Pompano, Rebecca R.; Platt, Carol E.; Karymov, Mikhail A.

2012-01-01

443

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

Code of Federal Regulations, 2010 CFR

... CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Standards and Certification...obscures the label on the engine, the marine vessel manufacturer must...S. EPA regulations for marine SI engines.”; (8) Family...

2010-07-01

444

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

Code of Federal Regulations, 2011 CFR

... CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Standards and Certification...obscures the label on the engine, the marine vessel manufacturer must...S. EPA regulations for marine SI engines.”; (8) Family...

2011-07-01

445

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

Code of Federal Regulations, 2014 CFR

... CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Standards and Certification...obscures the label on the engine, the marine vessel manufacturer must...S. EPA regulations for marine SI engines.”; (8) Family...

2014-07-01

446

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

Code of Federal Regulations, 2012 CFR

... CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Standards and Certification...obscures the label on the engine, the marine vessel manufacturer must...S. EPA regulations for marine SI engines.”; (8) Family...

2012-07-01

447

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

Code of Federal Regulations, 2013 CFR

... CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Standards and Certification...obscures the label on the engine, the marine vessel manufacturer must...S. EPA regulations for marine SI engines.”; (8) Family...

2013-07-01

448

67 FR 37548 - Control of Emissions of Air Pollution from New Marine Compression-Ignition Engines At or Above 30...  

Federal Register 2010, 2011, 2012, 2013, 2014

...emission standards for two-stroke engines on engine speed (with...control as counterpart four-stroke engines with comparable power...Standard Test Methods for Flash-Point [sect] 94...This paragaph (a) contains multiple tiers of emission...

2002-05-29

449

40 CFR 63.3166 - How do I determine the add-on control device emission destruction or removal efficiency?  

Code of Federal Regulations, 2013 CFR

...Requirements for the Combined Electrodeposition Primer, Primer-Surfacer, Topcoat, Final Repair, Glass Bonding Primer, and Glass Bonding Adhesive Emission Limitations § 63.3166 How do I determine the add-on control device emission...

2013-07-01

450

40 CFR 63.3166 - How do I determine the add-on control device emission destruction or removal efficiency?  

Code of Federal Regulations, 2011 CFR

...Requirements for the Combined Electrodeposition Primer, Primer-Surfacer, Topcoat, Final Repair, Glass Bonding Primer, and Glass Bonding Adhesive Emission Limitations § 63.3166 How do I determine the add-on control device emission...

2011-07-01

451

40 CFR 63.3166 - How do I determine the add-on control device emission destruction or removal efficiency?  

Code of Federal Regulations, 2012 CFR

...Requirements for the Combined Electrodeposition Primer, Primer-Surfacer, Topcoat, Final Repair, Glass Bonding Primer, and Glass Bonding Adhesive Emission Limitations § 63.3166 How do I determine the add-on control device emission...

2012-07-01

452

40 CFR 63.3166 - How do I determine the add-on control device emission destruction or removal efficiency?  

Code of Federal Regulations, 2014 CFR

...Requirements for the Combined Electrodeposition Primer, Primer-Surfacer, Topcoat, Final Repair, Glass Bonding Primer, and Glass Bonding Adhesive Emission Limitations § 63.3166 How do I determine the add-on control device emission...

2014-07-01

453

"Spontaneous" Strategy Use: Perspectives from Metacognitive Theory.  

ERIC Educational Resources Information Center

A metacognitive model was proposed as an explanatory framework for spontaneous strategy use. A study in which hyperactive children transferred newly acquired strategies following self-control training and attributional retraining served as an illustration of how components in the model can be used to better understand "spontaneity." (Author/LMO)

Borkowski, John G.; And Others

1987-01-01

454

Nitrogen oxides emission control options for coal-fired electric utility boilers  

SciTech Connect

Recent regulations have required reductions in emissions of nitrogen oxides (NOx) from electric utility boilers. To comply with these regulatory requirements, it is increasingly important to implement state-of-the-art NOx control technologies on coal-fired utility boilers. This paper reviews NOx control options for these boilers. It discusses the established commercial primary and secondary control technologies and examines what is being done to use them more effectively. Furthermore, the paper discusses recent developments in NOx controls. The popular primary control technologies in use in the United States are low-NOx burners and overfire air. Data reflect that average NOx reductions for specific primary controls have ranged from 35% to 63% from 1995 emissions levels. The secondary NOx control technologies applied on U.S. coal-fired utility boilers include reburning, selective noncatalytic reduction (SNCR), and selective catalytic reduction (SCR). Thirty-six U.S. coal-fired utility boilers have installed SNCR, and reported NOx reductions achieved at these applications ranged from 15% to 66%. Recently, SCR has been installed at 150 U.S. coal-fired utility boilers. Data on the performance of 20 SCR systems operating in the United States with low-NOx emissions reflect that in 2003, these units achieved NOx emission rates between 0.04 and 0.07 lb/106 Btu. 106 refs., 6 figs., 6 tabs.

Ravi K. Srivastava; Robert E. Hall; Sikander Khan; Kevin Culligan; Bruce W. Lani [U.S. Environmental Protection Agency, Research Triangle Park, NC (United States)

2005-09-01

455

Unsuccessful suicide by carbon monoxide: a secondary benefit of emissions control  

SciTech Connect

Emission systems and devices are required on automobile engines to reduce air pollution problems. Catalytic converters have been used on most 1975 and newer automobiles to reduce hydrocarbon and carbon monoxide (CO) emissions to a value that meets the Environmental Protection Agency requirements established for 1975 and 1976. The 1980-1981 Boise, Idaho, study shows that with a functioning catalytic converter either unmeasurable or sublethal quantities of CO appear in automobile exhaust. Thus, emissions control has produced a secondary benefit in reducing the number of suicides by CO poisoning from automobile exhaust fumes.

Landers, D.

1981-11-01

456

Nitrogen Oxides Emission Control Options for Coal-Fired Electric Utility Boilers  

Microsoft Academic Search

Recent regulations have required reductions in emissions of nitrogen oxides (NOx) from electric utility boilers. To comply with these regulatory requirements, it is increasingly important to implement state-of-the-art NOx control technologies on coal-fired utility boilers. This paper reviews NOx control options for these boilers. It discusses the established commercial primary and secondary control technologies and examines what is being done

Ravi K. Srivastava; Robert E. Hall; Sikander Khan; Kevin Culligan; Bruce W. Lani

2005-01-01

457

MOLECULAR SIEVE TESTS FOR CONTROL OF SULFURIC ACID PLANT EMISSIONS  

EPA Science Inventory

The report gives results of tests of a molecular sieve control system for sulfuric acid plant tail gas. The PuraSiv S uses molecular sieve adsorbent material that releases SO2 when heat is applied. The SO2 is recycled for an additional 2-3% production of acid. The report evaluate...

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