WorldWideScience

Sample records for flash photolysis techniques

  1. Laser flash photolysis studies of atmospheric free radical chemistry using optical diagnostic techniques

    Science.gov (United States)

    Wine, Paul H.; Nicovich, J. M.; Hynes, Anthony J.; Stickel, Robert E.; Thorn, R. P.; Chin, Mian; Cronkhite, Jeffrey A.; Shackelford, Christie J.; Zhao, Zhizhong; Daykin, Edward P.

    1993-01-01

    Some recent studies carried out in our laboratory are described where laser flash photolytic production of reactant free radicals has been combined with reactant and/or product detection using time-resolved optical techniques to investigate the kinetics and mechanisms of important atmospheric chemical reactions. Discussed are (1) a study of the radical-radical reaction O + BrO yields Br + O2 where two photolysis lasers are employed to prepare the reaction mixture and where the reactants O and BrO are monitored simultaneously using atomic resonance fluorescence to detect O and multipass UV absorption to detect BrO; (2) a study of the reaction of atomic chlorine with dimethylsulfide (CH3SCH3) where atomic resonance fluorescence detection of Cl is employed to elucidate the kinetics and tunable diode laser absorption spectroscopy is employed to investigate the HCl product yield; and (3) a study of the aqueous phase chemistry of Cl2(-) radicals where longpath UV absorption spectroscopy is employed to investigate the kinetics of the Cl2(-) + H2O reaction.

  2. Flash photolysis-shock tube studies

    Energy Technology Data Exchange (ETDEWEB)

    Michael, J.V. [Argonne National Laboratory, IL (United States)

    1993-12-01

    Even though this project in the past has concentrated on the measurement of thermal bimolecular reactions of atomic species with stable molecules by the flash or laser photolysis-shock tube (FP- or LP-ST) method using atomic resonance absorption spectrometry (ARAS) as the diagnostic technique, during the past year the authors have concentrated on studies of the thermal decompositions of selected chlorocarbon molecules. These studies are necessary if the degradation of chlorine containing organic molecules by incineration are to be understood at the molecular level. Clearly, destruction of these molecules will not only involve abstraction reactions, when possible, but also thermal decomposition followed by secondary reactions of the initially formed atoms and radicals. Studies on the thermal decomposition of CH{sub 3}Cl are complete, and the curve-of-growth for Cl-atom atomic resonance absorption has been determined. The new thermal decomposition studies are similar to those already reported for CH{sub 3}Cl.

  3. Laser Flash Photolysis Studies on Gallic Acid

    Institute of Scientific and Technical Information of China (English)

    ZHU Hong-Ping; ZHAO Hong-Wei; ZHANG Zhao-Xia; WANG Wen-Feng; YAO Si-De

    2006-01-01

    The transient species of gallic acid (GA) have been studied by 266 nm nanosecond laser flash photolysis in aqueous solution and acetonitrile. The intermediate with absorption at 320 nm was identified as excited triplet state (3GA*), the decay rates of which were obtained in aqueous solution and acetonitrile respectively. Energy transfer from 3GA* to β-carotene was observed and the energy transfer rate constant kent was determined to be 2.2 × 109 mol-1·L·s-1. GA underwent photoionization during photolysis and the quantum yield of photoionization was determined to be 0.12 at room temperature with KI as a reference.

  4. Flash photolysis using a light emitting diode: an efficient, compact, and affordable solution.

    Science.gov (United States)

    Bernardinelli, Yann; Haeberli, Christian; Chatton, Jean-Yves

    2005-06-01

    Flash photolysis has become an essential technique for dynamic investigations of living cells and tissues. This approach offers several advantages for instantly changing the concentration of bioactive compounds outside and inside living cells with high spatial resolution. Light sources for photolysis need to deliver pulses of high intensity light in the near UV range (300-380 nm), to photoactivate a sufficient amount of molecules in a short time. UV lasers are often required as the light source, making flash photolysis a costly approach. Here we describe the use of a high power 365 nm light emitting diode (UV LED) coupled to an optical fiber to precisely deliver the light to the sample. The ability of the UV LED light source to photoactivate several caged compounds (CMNB-fluorescein, MNI-glutamate, NP-EGTA, DMNPE-ATP) as well as to evoke the associated cellular Ca(2+) responses is demonstrated in both neurons and astrocytes. This report shows that UV LEDs are an efficient light source for flash photolysis and represent an alternative to UV lasers for many applications. A compact, powerful, and low-cost system is described in detail.

  5. Ozone Formation in Laser Flash Photolysis of Oxoacids and Oxoanions of Chlorine and Bromine

    DEFF Research Database (Denmark)

    Kläning, Ulrik; Sehested, Knud; Wolff, Thomas

    1984-01-01

    The kinetics of ozone formation in the photolysis of oxygen-containing solutions of HClO, ClO–, ClO–2, ClO–3, HBrO, BrO– and BrO–3 has been studied by laser flash photolysis and conventional flash photolysis. The usual assumption, that ozone only forms in the reaction of oxygen atoms in the spin-...

  6. The examination of berberine excited state by laser flash photolysis

    Science.gov (United States)

    Cheng, Lingli; Wang, Mei; Zhao, Ping; Zhu, Hui; Zhu, Rongrong; Sun, Xiaoyu; Yao, Side; Wang, Shilong

    2009-07-01

    The property of the excited triplet state of berberine (BBR) was investigated by using time-resolved laser flash photolysis of 355 nm in acetonitrile. The transient absorption spectra of the excited triplet BBR were obtained in acetonitrile, which have an absorption maximum at 420 nm. And the ratio of excitation to ionization of BBR in acetonitrile solvent was calculated. The self-decay and self-quenching rate constants, and the absorption coefficient of 3BBR* were investigated and the excited state quantum yield was determined. Furthermore utilizing the benzophenone (BEN) as a triplet sensitizer, and the β-carotene (Car) as an excited energy transfer acceptor, the assignment of 3BBR* was further confirmed and the related energy transfer rate constants were also determined.

  7. Studies on the Photodynamic Mechanism of Tetrapyrrole Compounds by Laser Flash Photolysis

    Institute of Scientific and Technical Information of China (English)

    DENG,Kui; CHEN,Zhi-Long; ZHOU,Xing-Ping; WANG,Wen-Feng; YANG,Xiao-Xia; TIAN,Juan

    2008-01-01

    Photodynamic therapy (PDT) is a promising new treatment technique which can potentially destroy unwanted and malignant tissues, such as those of cancer. The photodynamic mechanisms of three tetrapyrrole compounds:Mg-purpurin-18, tetra(meso-chlorophenyl)porphyrin (m-TCPP) and 2,7,12,18-tetramethyl-3,8-di[(1-isobutoxyl)-ethyl]-13,17-bis[3-di(2-chloroethyl)aminopropyl]porphyrin (TDBP) in acetonitrile were investigated by 355 nm laser flash photolysis. It was found that after laser flash photolysis (LFP), the excited states of TDBP and Mg-purpurin-18 could react with O2 and 1O2 was produced, which proved that TDBP and Mg-purpurin-18 took effects through type Ⅱ mechanism in PDT. This suggested that TDBP and Mg-purpurin-18 should be suitable for target tissues containing enough O2. Mg-purpurin-18 has two extra absorptions at 550 and 700 nm, which means it has broad choices of laser wavelength in PDT. It was also found that m-TCPP could be photoionized when excited with 355 nm laser under N2-saturated condition. It could also react with O2 to produce reactive oxygen species such as superoxide and the peroxide anions, but not 1O2. These were known as the Type Ⅰ mechanism. So m-TCPP could be used even at low oxygen concentration or more polar environments with good behavior in PDT. From the above studies on the three different tetrapyrrole compounds it could be concluded that the structure of porphin ring takes a main role in PDT. And there was important impact on the photodynamic mechanism for the functional group directly connecting with porphin ring, while little influence for the functional group indirectly connecting with porphin ring. These will be of great value in the discovery of new PDT drugs.

  8. Laser Flash Photolysis and Pulse Radiolysis of Iodate and Periodate in Aqueous Solution

    DEFF Research Database (Denmark)

    Kläning, U K; Sehested, Knud; Wolff, Thomas

    1981-01-01

    Species containing iodine in oxidation state six are formed by photolysis and radiolysis of aqueous iodate and periodate solutions in the following reactions: IO3–+ O–→ IO42–; IO3–+ OH → IO3; IVII+ eaq–→ IeVI and IVII [graphic omitted] I0VI+ O–(or OH). The present pulse radiolysis and laser flash...

  9. Steady-state and laser flash photolysis studies of 1-aziridinyl-1,2-dibenzoylalkenes

    Energy Technology Data Exchange (ETDEWEB)

    Barik, R.; Kumar, C.V.; Das, P.K.; George, M.V.

    1985-11-01

    Results of a photochemical study based on product analysis and 337.1-nm laser flash photolysis are reported for several cis- and trans-1,2-dibenzoylethylenes bearing aziridinyl groups at the 1-position. Products isolated from steady-state photolysis suggest facile ring expansions yielding pyrrolines as well as extrusion of alkenes from the aziridine moieties forming nitrene fragments, which subsequently undergo ring closure to give isoxazoles. Laser flash photolysis studies show transient absorption changes, explainable in terms of cis-trans photoisomerization and formation of azomethine ylides. The latter are also observed upon steady-state irradiation of these aziridinyl-1,2-dibenzoylethylenes in an EPA glass at 77 K. 46 references, 4 figures.

  10. The Reaction Kinetics of Neutral Free Radicals and Radical Ions Studied by Laser Flash Photolysis

    OpenAIRE

    Friedline, Robert Alan

    2004-01-01

    t-Butoxyl radical has been used as a chemical model for hydrogen abstractions in many enzymatic and biological systems. However, the question has arisen as to how well this reactive intermediate mimics these systems. In addressing this concern, absolute rate constants and Arrhenius parameters for hydrogen abstraction by t-butoxyl radical were measured for a broad class of substrates including amines, hydrocarbons, and alcohols using laser flash photolysis. Initially, no obvious reactivity ...

  11. Study of carboxyhemoglobin photodissociation with laser flash-photolysis

    Science.gov (United States)

    Kuzmin, Vasiliy V.; Salmin, Vladimir V.; Salmina, A. B.; Provorov, Alexander S.

    2004-08-01

    Assessment of the carboxyhemoglobin photodissociation has been performed under the native conditions. This investigation has a great importance for the development and creation of completely new approach for the treatment of carbon monoxide poisoning based on the photoinduced dissociation of carboxyhemoglobin. Photodissociation was registered on the experimental setup with crossing laser beams were pulsed Nd:YAG laser at the second harmonics wavelength (λ=532 nm) was used as a source of photolyzing radiation. Buffered solutions of whole human peripheral blood (PBS, pH=7.4) and diluted hemolized human peripheral blood were used. We found optimal parameters for the registration of the photodissociation such as using of buffered solutions of the whole human peripheral blood with the concentration of carboxyhemoglobin around 50% detection of dissociation of carboxyhemoglobin at the maximum of absorption within the Soret's band (435 nm). Dependence of photodissociation efficiency on the concentration of the complex in the tested solutions, as well as on the photolysis radiation intensity in both types of solutions was proved.

  12. Analysis of mebendazole binding to its target biomolecule by laser flash photolysis.

    Science.gov (United States)

    Jornet, Dolors; Bosca, Francisco; Andreu, Jose M; Domingo, Luis R; Tormos, Rosa; Miranda, Miguel A

    2016-02-01

    Mebendazole (MBZ) and related anticancer benzimidazoles act binding the β-subunit of Tubulin (TU) before dimerization with α-TU with subsequent blocking microtubule formation. Laser flash photolysis (LFP) is a new tool to investigate drug-albumin interactions and to determine binding parameters such as affinity constant or population of binding sites. The aim of this study was to evaluate the interactions between the nonfluorescent mebendazole (MBZ) and its target biomolecule TU using this technique. Before analyzing the MBZ@TU complex it was needed to determine the photophysical properties of MBZ triplet excited state ((3)MBZ(⁎)) in different media. Hence, (3)MBZ(⁎) showed a transient absorption spectrum with maxima at 520 and 375 nm and a lifetime much longer in acetonitrile (12.5 μs) than in water (260 ns). The binding of MBZ to TU produces a greater increase of the lifetime of (3)MBZ(⁎) (25 μs). This fact and the strong electron acceptor capability observed for (3)MBZ* evidence that MBZ must not be located close to any electron donor amino acid of TU such as its tryptophan or cysteine residues. Adding increasing amounts of MBZ to aqueous TU was determined the MBZ-TU binding constant (2.0 ± 0.5 × 10(5)M(-1) at 298K) which decreased with increasing temperature. The LFP technique has proven to be a powerful tool to analyze the binding of drug-TU systems when the drug has a detectable triplet excited state. Results indicate that LFP could be the technique of choice to study the interactions of non-fluorescent drugs with their target biomolecules.

  13. Analyzing Ca(2+) dynamics in intact epithelial cells using spatially limited flash photolysis.

    Science.gov (United States)

    Almassy, Janos; Yule, David I

    2013-01-01

    The production of saliva by parotid acinar cells is stimulated by Ca(2+) activation of Cl(-) and K(+) channels located in the apical plasma membrane of these polarized cells. Here we describe a paradigm for the focal photorelease of either Ca(2+) or an inositol 1,4,5 trisphosphate (InsP(3)) analog. The protocol is designed to be useful for investigating subcellular Ca(2+) dynamics in polarized cells with minimal experimental intervention. Parotid acinar cells are loaded with cell-permeable versions of the caged precursors (NP-EGTA-AM or Ci-InsP(3)/PM). Photolysis is accomplished using a spatially limited, focused diode laser, but the experiment can be readily modified to whole-field photolysis using a xenon flash lamp.

  14. A Laser Flash Photolysis Study of Azo-Compound Formation from Aryl Nitrenes at Room Temperature.

    Science.gov (United States)

    Ribblett, Alec Q; Poole, James S

    2016-06-30

    The species 4-nitrenopyridine 1-oxide is known to exhibit triplet nitrene dominated chemistry to yield azo-dimer products exclusively, even at room temperature. As such, this species, and its analogue 4-nitrenoquinoline 1-oxide, are useful models to probe the mechanism of formation of azo-dimers, which is postulated to proceed by self-reaction of the nitrene or reaction of nitrene with the parent azide. A laser flash photolysis study is described where the kinetics of formation of azo-dimer were found to be most adequately modeled by competition between both mechanisms, and rate coefficients for the competing reactions were determined.

  15. Measurement of OH reactivity by laser flash photolysis coupled with laser-induced fluorescence spectroscopy

    Science.gov (United States)

    Stone, Daniel; Whalley, Lisa K.; Ingham, Trevor; Edwards, Peter M.; Cryer, Danny R.; Brumby, Charlotte A.; Seakins, Paul W.; Heard, Dwayne E.

    2016-07-01

    OH reactivity (k'OH) is the total pseudo-first-order loss rate coefficient describing the removal of OH radicals to all sinks in the atmosphere, and is the inverse of the chemical lifetime of OH. Measurements of ambient OH reactivity can be used to discover the extent to which measured OH sinks contribute to the total OH loss rate. Thus, OH reactivity measurements enable determination of the comprehensiveness of measurements used in models to predict air quality and ozone production, and, in conjunction with measurements of OH radical concentrations, to assess our understanding of OH production rates. In this work, we describe the design and characterisation of an instrument to measure OH reactivity using laser flash photolysis coupled to laser-induced fluorescence (LFP-LIF) spectroscopy. The LFP-LIF technique produces OH radicals in isolation, and thus minimises potential interferences in OH reactivity measurements owing to the reaction of HO2 with NO which can occur if HO2 is co-produced with OH in the instrument. Capabilities of the instrument for ambient OH reactivity measurements are illustrated by data collected during field campaigns in London, UK, and York, UK. The instrumental limit of detection for k'OH was determined to be 1.0 s-1 for the campaign in London and 0.4 s-1 for the campaign in York. The precision, determined by laboratory experiment, is typically < 1 s-1 for most ambient measurements of OH reactivity. Total uncertainty in ambient measurements of OH reactivity is ˜ 6 %. We also present the coupling and characterisation of the LFP-LIF instrument to an atmospheric chamber for measurements of OH reactivity during simulated experiments, and provide suggestions for future improvements to OH reactivity LFP-LIF instruments.

  16. Laser flash-photolysis and gas discharge in N2O-containing mixture: kinetic mechanism

    Science.gov (United States)

    Kosarev, Ilya; Popov, Nikolay; Starikovskaia, Svetlana; Starikovskiy, Andrey; mipt Team

    2011-10-01

    The paper is devoted to further experimental and theoretical analysis of ignition by ArF laser flash-photolysis and nanosecond discharge in N2O-containing mixture has been done. Additional experiments have been made to assure that laser emission is distributed uniformly throughout the cross-section. The series of experiments was proposed and carried out to check validity of O(1D) determination in experiments on plasma assisted ignition initiated by flash-photolysis. In these experiments, ozone density in the given mixture (mixture composition and kinetics has been preliminary analyzed) was measured using UV light absorption in Hartley band. Good coincidence between experimental data and results of calculations have been obtained Temporal behavior of energy input, electric field and electric current has been measured and analyzed. These data are considered as initial conditions for numerical modeling of the discharge in O2:N2O:H2:Ar = 0.3:1:3:5 mixture. Ion-molecular reactions and reactions of active species production in Ar:H2:O2:N2O mixture were analyzed. The set of reactions to describe chemical transformation in the system due to the discharge action has been selected.

  17. Characterization of the transient species generated by the photoionization of Berberine: A laser flash photolysis study

    Science.gov (United States)

    Cheng, Ling-Li; Wang, Mei; Zhu, Hui; Li, Kun; Zhu, Rong-Rong; Sun, Xiao-Yu; Yao, Si-De; Wu, Qing-Sheng; Wang, Shi-Long

    2009-09-01

    Using 266 nm laser flash photolysis it has been demonstrated that Berberine (BBR) in aqueous solution is ionized via a mono-photonic process giving a hydrated electron, anion radical that formed by hydrated electron react with steady state of BBR, and neutral radical that formed from rapid deprotonation of the radical cation of BBR. The quantum yield of photoionization is determined to be 0.03 at room temperature with KI solution used as a reference. Furthermore utilizing pH changing method and the SO 4rad - radical oxidation method, the assignment of radical cation of BBR was further confirmed, the p Ka value of it was calculated, and the related set up rate constant was also determined.

  18. Nanosecond flash photolysis of unsymmetrical phenol-substituted calix[4]arene in cyclohexane

    Energy Technology Data Exchange (ETDEWEB)

    Feng Wen; Yuan Lihua [Sichuan Univ., Chengdu (China); Yao Side; Wang Wenfeng [Academia Sinica, Shanghai Institute of Nuclear Research, Shanghai (China)

    2000-03-01

    In the present paper the laser flash photolysis study of an unsymmetrical hindered phenol-substituted calix[4]arene(UPCA[4]OH) at 248 nm was carried out in cyclohexane at room temperature. The transient absorption spectra of UPCA[4]OH displayed two main absorption maxima at ca.330 nm and 520 nm with different grow and decay kinetics, and initial peak at 520 nm was assigned to the triplet state of the solute and the other peak at 330 nm was due to unsymmetrical phenol-substituted calix[4]aryloxyl radical. According to the kinetic analysis, the mechanism of the formation of the triplet and the calix[4]aryloxyl radical has been proposed. (author)

  19. Kinetics and product studies of the reaction ClO + BrO using flash photolysis-ultraviolet absorption

    Science.gov (United States)

    Sander, Stanley P.; Friedl, Randall R.

    1989-01-01

    The reaction between BrO and ClO was studied over the pressure range 50-700 torr and temperature range 220-400 K, using the flash photolysis-ultraviolet absorption method described by Watson et al. (1979). In order to investigate the mechanism of the BrO + ClO reaction, the product branch reactions Br + Cl2O yielding ClO + BrCl and Cl2O + h(nu) yielding products were examined. The rate constant for the overall reaction and the Arrhenius expression for the Br + Cl2O reaction are given, as well as the quantum yield for the production of atomic oxygen from the Cl2O photolysis.

  20. Laser flash photolysis study on 9-phenylxanthenium tetrafluoroborate: Identification of new features due to the triplet state

    Indian Academy of Sciences (India)

    Sanghamitra Banerjee; Anunay Samanta

    2011-01-01

    Laser flash photolysis study on highly fluorescent and stable salt of 9-phenylxanthenium cation in neutral condition has been carried out for the first time. A new transient absorption band of this extensively studied system that perhaps remained buried under the fluorescence envelope and hitherto undetected has been identified and attributed to the triplet state of the system. This oxygen-insensitive triplet-triplet absorption band in the 480-600 nm range is expected to trigger new studies exploring the reactivity of the triplet state of this system, which has so far received very little attention.

  1. Solvent effects on the O-neophyl rearrangement of 1,1-diarylalkoxyl radicals. A laser flash photolysis study.

    Science.gov (United States)

    Bietti, Massimo; Salamone, Michela

    2005-12-09

    [reaction: see text] A laser flash photolysis study has been carried out to assess solvent effects on the O-neophyl rearrangement of 1,1-diarylalkoxyl radicals. The rearrangement rate constant k decreases by increasing solvent polarity and an excellent correlation with negative slope is obtained between log k and the solvent polarity parameter E(T)N. These evidences are in full agreement with the previous indication that the extent of internal charge separation decreases on going from the starting 1,1-diarylalkoxyl radical to the transition state.

  2. Kinetics of calcium uptake by isolated sarcoplasmic reticulum vesicles using flash photolysis of caged adenosine 5'-triphosphate.

    Science.gov (United States)

    Pierce, D H; Scarpa, A; Topp, M R; Blasie, J K

    1983-11-08

    The kinetics of ATP-induced Ca2+ uptake by vesicular dispersions of sarcoplasmic reticulum were determined with a time resolution of about 10 ms, depending on the temperature. Ca2+ uptake was initiated by the addition of ATP through the flash photolysis of P3-1-(2-nitrophenyl)-ethyl adenosine 5'-triphosphate utilizing a frequency-doubled ruby laser and measured with two different detector systems that followed the absorbance changes of the metallochromic indicator arsenazo III sensitive to changes in the extravesicular [Ca2+]. The temperature range investigated was -2 to 26 degrees C. The Ca2+ ionophore A23187 was used to distinguish those features of the Ca2+ uptake kinetics associated with the formation of a transmembrane Ca2+ gradient. The acid-stable phosphorylated enzyme intermediate, E approximately P, was determined independently with a quenched-flow technique. Ca2+ uptake is characterized by at least two phases, a fast initial phase and a slow phase. The fast phase exhibits pseudo-first-order kinetics with a specific rate constant of 64 +/- 10 s-1 at 23-26 degrees C, an activation energy of 16 +/- 1 kcal mol-1, and a delta S* of approximately 5 cal deg-1 mol-1, is insensitive to the presence of a Ca2+ ionophore, and occurs simultaneously with the formation of the phosphorylated enzyme, E approximately P, with a stoichiometry of approximately 2 mol of Ca2+/mol of phosphorylated enzyme intermediate. The slow phase also exhibits pseudo-first-order kinetics with a specific rate constant of 0.60 +/- 0.09 s-1 at 25-26 degrees C, an activation energy of 22 +/- 1 kcal mol-1, and a delta S* of approximately 16 cal deg-1 mol-1, is inhibited by the presence of a Ca2+ ionophore, and has a stoichiometry of approximately 2 mol of Ca2+/mol of ATP hydrolyzed.

  3. Laser Flash Photolysis Studies of Radical-Radical Reaction Kinetics: The O((sup 3)P(sub J)) + BrO Reaction

    Science.gov (United States)

    Thorn, R. P.; Cronkhite, J. M.; Nicovich, J. M.; Wine, P. H.

    1997-01-01

    A novel dual laser flash photolysis-long path absorption-resonance fluorescence technique has been employed to study the kinetics of the important stratospheric reaction 0((sup 3)P(sub j)) + Br yields(k1) BrO((sup 2)P(sub J)) + O2 as a function of temperature (231-328 K) and pressure (25-150 Torr) in N2 buffer gas. The experimental approach preserves the principal advantages of the flash photolysis method, i.e., complete absence of surface reactions and a wide range of accessible pressures, but also employs techniques which are characteristic of the discharge flow method, namely chemical titration as a means for deducing the absolute concentration of a radical reactant and use of multiple detection axes. We find that k1 is independent of pressure, and that the temperature dependence of k1 is adequately described by the Arrhenius expression k1(T) = 1.91 x 10(exp -11)(230/J) cu cm/ molecule.s; the absolute accuracy of measured values for k1 is estimated to vary from +/- 20 percent at at T approximately 230 K to +/- 30 percent at T approximately 330 K. Our results demonstrate that the O((sup 3)P(sub j)) + BrO rate coefficient is significantly faster than previously 'guesstimated,' and suggest that the catalytic cycle with the O((sup 3)P(sub j)) + BrO reaction as its rate-limiting step is the dominant stratospheric BrO(x), odd-oxygen destruction cycle at altitudes above 24 km.

  4. Characterization of the cation binding sites of the purple membrane. Electron spin resonance and flash photolysis studies

    Energy Technology Data Exchange (ETDEWEB)

    Dunach, M.; Seigneuret, M.; Rigaud, J.L.; Padros, E.

    1987-02-24

    The binding of Mn/sup 2 +/ and La/sup 3 +/ to the blue membrane prepared by deionization of the Halobacterium halobium purple membrane has been studied by electron spin resonance (ESR) spectroscopy, visible absorption spectroscopy, and flash photolysis. ESR studies indicated that 10 Mn/sup 2 +/ binding sites are present per bacteriorhodopsin monomer. Five high- and medium-affinity sites, normally occupied by Ca/sup 2 +/ and Mg/sup 2 +/ in the purple membrane, as well as five low-affinity sites were found. Proteolysis and chemical modification experiments indicated that the low-affinity sites are located on the bacteriorhodopsin C-terminal segment, while the high- and medium-affinity sites involve other carboxyl groups of the protein. Competition experiments indicated that La/sup 2 +/ binds much more strongly than Mn/sup 2 +/ to these sites. Visible absorption spectroscopy and flash photolysis experiments indicated that binding of Mn/sup 2 +/ or La/sup 3 +/ regenerates both the purple color and formation of the M/sub 4//sup 12/ intermediate. The effect occurs progressively as cations bind to the high- and medium-affinity sites, bound La/sup 3 +/ being more effective than bound Mn/sup 2 +/. It is suggested that divalent cations support both the purple color and proton-pumping activity by rendering less negative the surface potential of the purple membrane. This process may promote deprotonation of the counterion of the retinal Schiff base and possibly of other functional groups. On the other hand, it is proposed that the inhibitory effect of La/sup 3 +/ is mainly due to binding to a site distinct from those of divalent cations.

  5. Influence of Pressure in Flash Sintering Technique

    Science.gov (United States)

    Pcheliakov, D. A.; Yurlova, M. S.; Grigoryev, E. G.; Olevsky, E. A.

    An innovative pressure-assisted flash-sintering technique has been developed to investigate the effect of pressure applied on microstructure and the sintering behavior of titanium dioxide. There are numerous applications for titanium dioxide in ceramics including microeletronics, glass ceramics, refractive materials, structural ceramics and titanium-containing ceramic materials and chemical intermediates. The traditional sintering of titanium dioxide usually requires several hours at over 1200 °C. The conducted research indicates that titanium dioxide can be sintered to full density in only a few seconds at 800-1000 °C, when subjected to a DC electrical field at a certain temperature moment.

  6. Flash Infrared Thermography Contrast Data Analysis Technique

    Science.gov (United States)

    Koshti, Ajay

    2014-01-01

    This paper provides information on an IR Contrast technique that involves extracting normalized contrast versus time evolutions from the flash thermography inspection infrared video data. The analysis calculates thermal measurement features from the contrast evolution. In addition, simulation of the contrast evolution is achieved through calibration on measured contrast evolutions from many flat-bottom holes in the subject material. The measurement features and the contrast simulation are used to evaluate flash thermography data in order to characterize delamination-like anomalies. The thermal measurement features relate to the anomaly characteristics. The contrast evolution simulation is matched to the measured contrast evolution over an anomaly to provide an assessment of the anomaly depth and width which correspond to the depth and diameter of the equivalent flat-bottom hole (EFBH) similar to that used as input to the simulation. A similar analysis, in terms of diameter and depth of an equivalent uniform gap (EUG) providing a best match with the measured contrast evolution, is also provided. An edge detection technique called the half-max is used to measure width and length of the anomaly. Results of the half-max width and the EFBH/EUG diameter are compared to evaluate the anomaly. The information provided here is geared towards explaining the IR Contrast technique. Results from a limited amount of validation data on reinforced carbon-carbon (RCC) hardware are included in this paper.

  7. Flash Vacuum Pyrolysis - Techniques and Reactions.

    Science.gov (United States)

    Wentrup, Curt

    2017-07-04

    While pyrolysis reactions have been performed since ancient times and been crucial for the invention of several technologies, the methodology now commonly known as flash vacuum pyrolysis, FVP (or flash vacuum thermolysis, FVT) had its early beginnings in the 1940s and1950s, mainly through mass spectrometric detection of pyrolytically formed free radicals. In the 1960s many organic chemists started performing FVP experiments with the purpose of isolating new and interesting compounds and understanding pyrolysis processes. Meanwhile, many different types of apparatus and techniques have been developed, and it is the purpose of this review to present the most important methods as well as a survey of typical reactions and observations that can be achieved with the various techniques. This includes preparative FVP, chemical trapping reactions, matrix isolation and low temperature spectroscopy of reactive intermediates and unstable molecules, the use of online mass, photoelectron, microwave and millimeterwave spectroscopies, gas-phase laser pyrolysis, pulsed pyrolysis with supersonic jet expansion, very low pressure pyrolysis for kinetic investigations, solution-spray and falling-solid FVP for involatile compounds, and pyrolysis over solid supports and reagents. Moreover, the combination of FVP with matrix isolation and photochemistry is a powerful tool for investigations of reaction mechanism. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Chemistry of bifunctional photoprobes. 3 -- Correlation between the efficiency of CH insertion by photolabile chelating agents and lifetimes of singlet nitrenes by flash photolysis: First example of photochemical attachment of {sup 99m}Tc-complex with human serum albumin

    Energy Technology Data Exchange (ETDEWEB)

    Pandurangi, R.S.; Lusiak, P.; Kuntz, R.R.; Volkert, W.A. [Univ. of Missouri, Columbia, MO (United States). Dept. of Chemistry; Rogowski, J.; Platz, M.S. [Ohio State Univ., Columbus, OH (United States). Dept. of Chemistry

    1998-11-27

    Systematic functionalization of perfluoroaryl azides with chelating agents capable of complexing transition metals produces a new class of bifunctional photolabile chelating agents (BFPCAs). The strategy is shield the azide functionality from the electronic and steric influence of the electron-rich metal Pd through ester and amide bridges raised CH insertion efficiency to unprecedented levels (>92%) in a model solvent (cyclohexane). In contrast, perfluoroaryl azides attached to chelating agents via hydrazones show no significant CH insertion in cyclohexane upon photolysis. Measurements of the lifetimes of the singlet nitrenes derived from these agents by flash photolysis techniques correlate well with the efficiency of CH insertion by demonstrating longer lifetimes (10--50 times) for singlet nitrenes derived from azidotetrafluorinated esters and amides compared with the related hydrazones, which failed to yield significant CH insertion. A representative BFPCA 12 is chelated to diagnostic radionuclide {sup 99m}Tc and covalently attached to human serum albumin via photochemical activation extending the favorable bimolecular insertion characteristics of BFPCA to tracer level concentrations in buffer conditions. Flash photolysis experiments correlate singlet nitrene lifetimes with the efficiency of intermolecular insertion reactions. This work provides new photo-cross-linking technology, useful in radiodiagnostics and radiotherapy in nuclear medicine.

  9. Kinetic studies on the temperature dependence of the BrO + BrO reaction using laser flash photolysis.

    Science.gov (United States)

    Ferracci, Valerio; Hino, Kaori; Rowley, David M

    2011-05-07

    The BrO self-reaction, BrO + BrO → products (1), has been studied using laser flash photolysis coupled with UV absorption spectroscopy over the temperature range T = 266.5-321.6 K, under atmospheric pressure. BrO radicals were generated via laser photolysis of Br(2) in the presence of excess ozone. Both BrO and O(3) were monitored via UV absorption spectroscopy using charge-coupled device (CCD) detection. Simultaneous fitting to both temporal concentration traces allowed determination of the rate constant of the two channels of , BrO + BrO → 2Br + O(2) (1a); BrO + BrO → Br(2) + O(2) (1b), hence the calculation of the overall rate of and the branching ratio, α: k(1a)/cm(3) molecule(-1) s(-1) = (1.92 ± 1.54) × 10(-12) exp[(126 ± 214)/T], k(1b)/cm(3) molecule(-1) s(-1) = (3.4 ± 0.8) × 10(-13) exp[(181 ± 70)/T], k(1)/cm(3) molecule(-1) s(-1) = (2.3 ± 1.5) × 10(-12) exp(134 ± 185 /T) and α = k(1a)/k(1) = (0.84 ± 0.09) exp[(-7 ± 32)/T]. Errors are 1σ, statistical only. Results from this work show a weaker temperature dependence of the branching ratio for channel (1a) than that found in previous work, leading to values of α at temperatures typical of the Polar Boundary Layer higher than those reported by previous studies. This implies a shift of the partitioning between the two channels of the BrO self-reaction towards the bromine atom and hence directly ozone-depleting channel (1a). This journal is © the Owner Societies 2011

  10. Continuous irradiation and flash-photolysis studies of new[3H]naphtho[2,1-b]pyrans linked by covalent bonds to oligothiophene units. Effect of thiophene substituents on the photochromism.

    Science.gov (United States)

    Frigoli, Michel; Pimienta, Véronique; Moustrou, Corinne; Samat, André; Guglielmetti, Robert; Aubard, Jean; Maurel, François; Micheau, Jean-Claude

    2003-08-01

    The influence of oligothiophene substituents on five new [3H]naphtho[2,1-b]pyrans has been investigated using flash photolysis and continuous irradiation techniques. Photochromic properties strongly depend on the number and position of the thienyl units. Thienyl substitution increases the UV/visible absorbance of the lower energy transition of both the naphthopyran and merocyanine isomers. The rate constants of the thermal fading processes also increase with the number of thiophenic entities. Although several minor photoisomers, whose relative amounts depend on the irradiation conditions could be involved, it has been assumed that under continuous monochromatic irradiation, the evolution of the photochromic reaction can be described by the formation of only one photoisomer. Under these conditions, quantum yields of photocolouration and molar absorption coefficients of the non-isolable photomerocyanine isomer were evaluated by photokinetic analysis. Flash-photolytic colourability can be interpreted using continuous irradiation parameters. A linear correlation has been established between experimental and calculated colourability. This result shows that similar photochromic reactions leading to similar photoisomers are triggered either by polychromatic flash photolysis or by continuous monochromatic irradiation.

  11. Pulse radiolysis, flash photolysis, and shock wave study of the recombination H + benzyl yields toluene at 300 and 1,300-1,650 K

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, L.; Hippler, H.; Pagsberg, P.; Reihs, C.; Troe, J. (Institut fuer Physikalische Chemie der Universitaet Goettingen (West Germany) Riso National Laboratory (Denmark))

    1990-06-28

    Pulse radiolysis, discharge flash photolysis, and laser flash photolysis have been employed to study the recombination reaction H + benzyl {yields} toluene at room temperature. Both H atoms and benzyl radicals were monitored. The same reaction was studied directly in shock waves between 1,300 and 1.650 K. The value of the high-pressure recombination rate constant of (2.5 {plus minus} 0.8) {times} 10{sup 14} cm{sup 3} mol{sup {minus}1} s{sup {minus}1} was found to be independent of the temperature between 300 and 1,650 K. It is argued that high-pressure rate constants for other recombination reactions should also have very small temperature coefficients over wide temperature ranges. Room temperature rate constants for addition of H atoms to toluene, cycloheptatriene, p-xylene, benzene, phenyl, and p-methylbenzyl are also reported.

  12. Flash and Continuous Photolysis Studies of the Thionitrosyl Complex Cr(CH3CN)5(NS)2+ and the Nitric Oxide Analogs. Reactions of Nitrogen Monosulfide in Solution

    DEFF Research Database (Denmark)

    Dethlefsen, Johannes Wied; Hedegård, Erik; Rimmer, R. Dale

    2009-01-01

    Photolysis of the thionitrosyl complex Cr(CH3CN)5(NS)2+ (1) in acetonitrile solution leads to the dissociation of nitrogen monosulfide (NS).  In deaerated solution, this reaction is reversible, and flash photolysis studies demonstrate that NS reacts with Cr(CH3CN)62+ according to the rate law d[1...

  13. Decay kinetics of benzophenone triplets and corresponding free radicals in soft and rigid polymers studied by laser flash photolysis.

    Science.gov (United States)

    Levin, Peter P; Efremkin, Alexei F; Sultimova, Natalie B; Kasparov, Valery V; Khudyakov, Igor V

    2014-01-01

    The kinetics of transients formed under photoexcitation of benzophenone (B) dissolved in three different polymers was studied by ns laser flash photolysis. These polymers were the soft rubbers poly (ethylene-co-butylene) (EB), polystyrene block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) and hard polystyrene (PS). We monitored the decay kinetics of triplet state (3)B(*) and of ketyl radicals BH(●). We observed exponential decay of (3)B(*) and two-stage decay kinetics of BH(●) in EB. The first stage is a fast cage recombination of a radical pair (BH(●), radical of polymer R(●)). The second slow stage of BH(●) decay follows the second-order law with a relatively high rate constant, which corresponds to recombination of BH(●) in a homogeneous liquid with a viscosity of only ~0.1 P (about five times of 2-propanol viscosity). Application of a magnetic field (MF) of 0.2 T leads to deceleration of both stages of BH(●) decay in EB by approximately 20%. Decay kinetics of both transients were observed in SEBS. There was no MF effect on BH(●) decay in SEBS. We only observed (3)B(*) in PS. Decay kinetics of (3)B(*) in this case were described as polychromatic dispersive first-order kinetics. We discuss the effects of polymer structure on transient kinetics and the MF effect.

  14. Direct determination of rate constants for coupling between aromatic radical anions and alkyl and benzyl radicals by laser-flash photolysis

    DEFF Research Database (Denmark)

    Lund, T.; Christensen, P.; Wilbrandt, Robert Walter

    2003-01-01

    Coupling rates between the radicals methyl, n-, sec-, tert-butyl and benzyl (R-.) and the aromatic radical anions of 1,4-dicyanonaphthalene, 9,10-dicyanoanthracene and fluorenone (A(-.)) have been obtained using a new laser-flash photolysis method. The radicals R-. and the radical anions A(-.) were...... generated by a photoinduced electron transfer reaction between the aromatic compound A and the alkyl or benzyl triphenylborate anion RB(Ph)(3)(-). For the first time the rate constants of the coupling reaction between methyl and benzyl radicals with aromatic radical anions have been obtained. For all...... of the radicals and the structure and standard potentials of the aromatic radical anions....

  15. Flash photolysis of cutinase

    DEFF Research Database (Denmark)

    Neves Petersen, Teresa; Klitgaard, Søren; Skovsen, Esben;

    2009-01-01

    enzyme, Fusarium solani pisi cutinase, a lipolytic enzyme. With this purpose, we acquired transient absorption data of cutinase, with supplemental experimental data on tryptophan (Trp) and lysozyme as reference molecules. We here report formation kinetics and lifetimes of transient chemical species...... created upon UV excitation of aromatic residues in proteins. Two proteins, lysozyme and cutinase, as well as the free amino acid Trp, were studied under acidic, neutral, and alkaline conditions. The shortest-lived species is assigned to solvated electrons (lifetimes of a few microseconds to nanoseconds......), whereas the longer-lived species are assigned to aromatic neutral and ionic radicals, Trp triplet states, and radical ionic disulphide bridges. The pH-dependent lifetimes of each species are reported. Solvated electrons ejected from the side chain of free Trp residues and aromatic residues in proteins...

  16. Time-resolved infrared spectral studies of intermediates formed in the laser flash photolysis of Mn(CO){sub 5}CH{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Boese, W.T.; Ford, P.C. [Univ. of California, Santa Barbara, CA (United States)

    1994-09-01

    Laser flash photolysis (308 nm) of Mn(CO){sub 5}CH{sub 3} (I) in different solvents leads predominantly to CO photodissociation and the formation of reactive intermediates formulated as the solvento complexes cis-Mn(CO){sub 4}(solv)CH{sub 3}. This conclusion is based upon the solvent sensitivity of the time-resolved infrared spectra and the dynamics of reactions with various ligands. For example, the reaction of cis-Mn(CO){sub 4}(solv)CH{sub 3} with CO displays second-order kinetics with a rate constant k{sub co} nearly 8 orders of magnitude larger for solv = perfluoro-(methylcyclohexane) than for solv = tetrahydrofuran. The k{sub l} values for the second-order reaction of cis-Mn(CO){sub 4}(solv)CH{sub 3} in cyclohexane with various ligands L follow the approximate order 4-phenylpyridine H{sub 2}O THF > P(OMe){sub 3} PPh{sub 3} > CO N{sub 2}. The quantitative behaviors of intermediates seen in the flash photolysis of I are compared with those seen in similar studies of the acetyl complex Mn(Co){sub 5}(COCH){sub 3} (II). 24 refs., 6 figs., 2 tabs.

  17. Photolysis of Periodate and Periodic Acid in Aqueous Solution

    DEFF Research Database (Denmark)

    Sehested, Knud; Kläning, U. K.

    1978-01-01

    The photochemistry of periodate and periodic acid in aqueous solution was studied (i) by quantum yield measurements at low light intensity (ii) by flash photolysis, and (iii) by photolysis of glassy samples at 77 K. The photochemical studies were supplemented with pulse radiolysis studies...... of aqueous periodate solutions and with kinetic studies using stopped-flow technique. In strongly alkaline solution the photodecomposition of periodate proceeds via formation of O– and IVI. At pH

  18. Associated electron and proton transfer between Acridine and Triethylamine in AOT reverse micelles probed by laser flash photolysis with magnetic field

    Science.gov (United States)

    Sarangi, Manas Kumar; Basu, Samita

    2011-04-01

    Laser flash photolysis with magnetic field (MF ˜0.08 T) has been used to study interaction between Acridine (Acr) and Triethylamine (TEA) in reverse micelles with w0 = 2.5-40. Dynamic protonation equilibrium exists between 3Acr and 3AcrH +. The intermediates indicate excited-state proton transfer (PT) between 3AcrH + and TEA. However, application of MF highlights the formation of geminate radical ion pairs (RIPs) with triplet spin-correlation, a signature of latent photoinduced electron transfer between 3AcrH + and TEA co-exists with PT. Magnetic field effect (MFE) is prominent for smaller w0 showing importance of optimum separation between RIP to maximize MFE, whereas PT remains unaltered.

  19. Laser flash photolysis and magnetic-field-effect studies on interaction of thymine and thymidine with menadione: role of sugar in controlling reaction pattern

    Directory of Open Access Journals (Sweden)

    Adity Bose, Debarati Dey and Samita Basu

    2008-01-01

    Full Text Available The magnetic field effect (MFE in conjunction with laser flash photolysis has been used for the study of the interaction of one of the small drug like quinone molecules, 2-methyl, 1,4-naphthoquinone, commonly known as menadione (MQ, with one of the DNA bases, thymine (THN, and its corresponding nucleoside, thymidine (THDN, in acetonitrile (ACN and sodium dodecylsulfate (SDS micelles. It has been observed that THN undergoes electron transfer (ET and hydrogen (H abstraction with MQ, while THDN undergoes only H abstraction in both the media. However, our earlier studies showed that a purine base, adenine (ADN, and its nucleoside, 2'-deoxyadenosine (ADS, undergo ET in ACN and H abstraction in SDS. Here we have attempted to explain the differences in the reactions of these DNA bases with MQ. We also reveal the crucial role of a sugar unit in altering the behavior of purine and pyrimidine bases with respect to ET and H abstraction.

  20. Investigation of molecular mechanisms in photodynamic action and radiobiology with nanosecond flash photolysis and pulse radiolysis. Progress report, July 1, 1976--September 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Grossweiner, L.I.

    1977-06-01

    Laser flash photolysis investigations on aromatic amino acids and proteins have demonstrated that monophotonic electron ejection is the major initial act, leading to e/sup -//sub aq/ and the corresponding aromatic radicals, followed by back reactions limited by available e/sup -//sub aq/ scavengers. Results with ribonuclease A, lysozyme and carboxypeptidase A have led to information about the relationship of the photoionization efficiency of aromatic residues to the microenvironment. Measurements on the decay kinetics of photoelectrons have shown that the lifetimes and their dependence on scavenger concentrations and dose are inconsistent with homogeneous reactions. A new theory is proposed in which the photoelectron diffuses through the medium as a quasi-free particle, where original pair-recombination competes with scavenging and pair-pair interactions. This theory is in good agreement with laser flash photolysis studies on I/sup -/, FE(CN)/sub 6//sup 4 -/, tryptophan and tyrosine and consistent with earlier photochemical scavenging measurements. The general analysis of radition sensitivity has been extended to suspensions of large biological targets, such as vesicles, viruses and cells, particularly where the radical diffusion length is smaller than or comparable to the collision radius. The development is exemplified with new work on inactivation of T7 bacteriophag by 25 MeV electrons and photodynamic inactivation of Saccharomyces cerevisiae. Detailed studies on yeast have shown that the sensitivity to singlet oxygen attack depends on the temperature and the culture growth phase. Spin label ESR measurements indicate that he conditions of low photosensitivity parallel low membrane fluidity.

  1. A comparison of radiometric calibration techniques for lunar impact flashes

    Science.gov (United States)

    Suggs, R. M.; Ehlert, S. R.; Moser, D. E.

    2017-09-01

    Video observations of lunar impact flashes have been made by a number of researchers since the late 1990's and the problem of determination of the impact energies has been approached in different ways Bellot Rubio et al. (2000a, b), Yanagisawa et al. (2008), Bouley et al. (2012), Suggs et al. (2014), Rembold and Ryan (2015), Ortiz et al. (2015), Madiedo et al. (2015). The wide spectral response of the unfiltered video cameras in use for all published measurements necessitates color correction for the standard filter magnitudes available for the comparison stars but this is not typically considered. In our approach, the published color of the comparison star and an estimate of the color of the impact flash is used to correct it to the chosen filter bandpass. Magnitudes corrected to standard filters are then used to determine the luminous energy in the filter bandpass according to the stellar atmosphere calibrations of Bessell et al. (1998). In this paper we compare the various photometric calibration techniques and calculation of luminous energy (radiometry) of impact flashes. This issue has significant implications for determination of luminous efficiency, predictions of impact crater sizes for observed flashes, and the determination of the flux of meteoroids in the 10 s of grams to kilograms mass range.

  2. Infrared Contrast Analysis Technique for Flash Thermography Nondestructive Evaluation

    Science.gov (United States)

    Koshti, Ajay

    2014-01-01

    The paper deals with the infrared flash thermography inspection to detect and analyze delamination-like anomalies in nonmetallic materials. It provides information on an IR Contrast technique that involves extracting normalized contrast verses time evolutions from the flash thermography infrared video data. The paper provides the analytical model used in the simulation of infrared image contrast. The contrast evolution simulation is achieved through calibration on measured contrast evolutions from many flat bottom holes in the subject material. The paper also provides formulas to calculate values of the thermal measurement features from the measured contrast evolution curve. Many thermal measurement features of the contrast evolution that relate to the anomaly characteristics are calculated. The measurement features and the contrast simulation are used to evaluate flash thermography inspection data in order to characterize the delamination-like anomalies. In addition, the contrast evolution prediction is matched to the measured anomaly contrast evolution to provide an assessment of the anomaly depth and width in terms of depth and diameter of the corresponding equivalent flat-bottom hole (EFBH) or equivalent uniform gap (EUG). The paper provides anomaly edge detection technique called the half-max technique which is also used to estimate width of an indication. The EFBH/EUG and half-max width estimations are used to assess anomaly size. The paper also provides some information on the "IR Contrast" software application, half-max technique and IR Contrast feature imaging application, which are based on models provided in this paper.

  3. Investigation of molecular mechanisms in photodynamic action and radiobiology with nanosecond flash photolysis and pulse radiolysis. Progress report, October 1, 1980-September 30, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Grossweiner, L I

    1981-06-01

    Laser flash photolysis experiments have led to a new mechanism for the ultraviolet photolysis of aqueous tryptophan (Trp), indole (Ind) and certain indole derivatives. Excitation at 265 nm leads to photoionization via a pre-fluorescent state with thermal activation. A new formula is proposed for predicting enzyme inactivation quantum yields. The predictions are in good agreement with measurements on six important enzymes at 254 nm and 280 nm. Kinetics models have been developed and tested for important stages in the photosensitization of DNA to near-ultraviolet radiation by furocoumarin compounds currently used for PUVA therapy (psoralen plus UV-A) of psoriasis and other human skin diseases. Experiments on photobinding of psoralen (Ps) and 8-methoxypsoralen (8-MOP) to calf thymus DNA are consistent with the assumption that equilibrium dark complexing of the furocoumarin to the DNA is a precondition for the formation of covalent monoadducts and cross-links. Singlet oxygen generation by furocoumarins has been investigated with liposomes and human erythrocytes (rbc). Results obtained with 3-carbethoxypsoralen (3-CPs), an experimental alternate PUVA sensitizer claimed to be non-tumorigenic, show that 3-CPs interacts with liposome and rbc membranes in the dark. Studies on photosensitization of egg lecithin liposomes by methylene blue (MB) incorporated in the membrane have led to the new result that membrane lysis is a two-stage process. The first stage induced by red light irradiation leads to membrane damage initiated by O/sub 2/*. Membrane lysis takes place in the dark, second stage under the action of mild hydrodynamic stress, such as slow gas bubbling.

  4. GeckoFTL: Scalable Flash Translation Techniques For Very Large Flash Devices

    DEFF Research Database (Denmark)

    Dayan, Niv; Bonnet, Philippe; Idreos, Stratos

    2016-01-01

    The volume of metadata needed by a flash translation layer (FTL) is proportional to the storage capacity of a flash device. Ideally, this metadata should reside in the device's integrated RAM to enable fast access. However, as flash devices scale to terabytes, the necessary volume of metadata...

  5. Formation and decay of ( sup 3 P sub J )O atoms in the laser flash photolysis of chlorine dioxide (OClO) at 308 nm

    Energy Technology Data Exchange (ETDEWEB)

    Colussi, A.J. (California Institute of Technology, Pasadena (USA))

    1990-12-27

    The primary quantum yields of O({sup 3}P{sub J}) and Cl({sup 2}P{sub 3/2}) atoms in the laser flash photolysis of OClO(g) at 308 nm and 298 K and the kinetics of the subsequent oxygen atom decay have been investigated by time-resolved atomic resonance fluorescence measurements. The determined quantum yields are {phi}{sub o} = 1.02 {plus minus} 0.05 and {phi}{sub Cl} < 0.01. Second-order rate constants for the reaction between O atoms and OClO are pressure dependent with a finite intercept. The rate constant for the bimolecular channel O + OClO {yields} O{sub 2} + ClO (1) has a value of k{sub 1} = (1.6 {plus minus} 0.4) {times} 10{sup {minus}13} cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}. Termolecular reaction rates for O + OClO + Ar {yields} ClO{sub 3} + Ar (2) can be fit with k{sub 20} = (1.4 {plus minus} 0.3) {times} 10{sup {minus}31} cm{sup 6} molecule{sup {minus}2}s{sup {minus}1} and k{sub 2{infinity}} = (3.1 {plus minus} 0.8) {times} 10{sup {minus}11} cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}.

  6. Investigation of molecular mechanisms in photodynamic action and radiobiology with nanosecond flash photolysis and pulse radiolysis. Progress report, July 1, 1975--June 30, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Grossweiner, L.I.

    1976-03-01

    Flash photolysis studies have shown that exposed tyrosyl or tryptophyl residues of enzymes are photoionized at approximately the same quantum efficiency as the aqueous amino acids. Comparisons with permanent damage indicate that this primary process contributes to inactivation when a photolyzed aromatic residue is essential or is located adjacent to a catalytic, non-chromoporic residue. Studies on sensitization by the phototherapeutic drug, 8-methoxypsoralen (8-MOP), show the triplet state can lead to singlet oxygen generation and that weak binding to poly (dA-dT) suppresses this process. 8-MOP was found to be potent sensitizer of yeast photoinactivation with negligible post-irradiation recovery. Spinlable ESR measurements made on yeast cells after photodynamic treatment show that the membrane damage generated by the penetrating dye Toluidine Blue 0 is more extensive than the external dye, Eosin Y. In related ionizing radiation studies, it was found that 8-MOP is an anoxic radiosensitizer of T7 phage, attributed to enhancement of crosslinks; that complexing of eosin to lysozyme sensitizes the enzyme to oxidizing radicals; that the reactions of Br/sub 2//sup -/ and (CNS)/sub 2//sup -/ with tryptophan generate the same initial radical as uv-excited photoionization.

  7. Radiation Chemistry of Xenon Trioxide, Xenate and Perxenate and Photochemistry of Perxenate - A Pulse Radiolysis and Laser Flash-Photolysis Study

    DEFF Research Database (Denmark)

    Kläning, U. K.; Sehested, Knud; Wolff, T.

    1982-01-01

    Unstable species containing xenon in the formal oxidation states five, XeV, and seven, XeVII, were observed by pulse radiolysis of aqueous solutions of xenon trioxide, XeO3, at pH 8–9 and of xenate, HXeO–4, at pH 11–13. XeVII and species containing xenon in the formal oxidation state nine, Xe......IX, were observed in pulse radiolysis and flash photolysis of aqueous solutions of perxenate, HXeO3–6, at pH 11–13. The formulae HXeO3 and H3XeO2–7 are assumed for XeV and XeIX, whereas the observations suggest that XeVII corresponds to three different species for which the formulae HXeO4, HXeO2–5 and H3XeO......2–6 are assumed. HXeO3 and H3XeO2–6 are formed in reactions of the hydrated electron with XeO3 and HXeO3–6, respectively. HXeO4 and H3XeO2–7 are formed in reactions of the hydroxyl radical with XeO3 and HXeO3–6 in which the hydroxyl radical adds to a ligand oxygen atom to form peroxy compounds. HXe...

  8. Photolysis frequency measurement techniques: results of a comparison within the ACCENT project

    Directory of Open Access Journals (Sweden)

    K. C. Clemitshaw

    2008-09-01

    Full Text Available An intercomparison of different radiometric techniques measuring atmospheric photolysis frequencies j(NO2, j(HCHO and j(O1D was carried out in a two-week field campaign in June 2005 at Jülich, Germany. Three double-monochromator based spectroradiometers (DM-SR, three single-monochromator based spectroradiometers with diode-array detectors (SM-SR and seventeen filter radiometers (FR (ten j(NO2-FR, seven j(O1D-FR took part in this comparison. For j(NO2, all spectroradiometer results agreed within ±3%. For j(HCHO, agreement was slightly poorer between −8% and +4% of the DM-SR reference result. For the SM-SR deviations were explained by poorer spectral resolutions and lower accuracies caused by decreased sensitivities of the photodiode arrays in a wavelength range below 350 nm. For j(O1D, the results were more complex within +8% and −4% with increasing deviations towards larger solar zenith angles for the SM-SR. The direction and the magnitude of the deviations were dependent on the technique of background determination. All j(NO2-FR showed good linearity with single calibration factors being sufficient to convert from output voltages to j(NO2. Measurements were feasible until sunset and comparison with previous calibrations showed good long-term stability. For the j(O1D-FR, conversion from output voltages to j(O1D needed calibration factors and correction functions considering the influences of total ozone column and elevation of the sun. All instruments showed good linearity at photolysis frequencies exceeding about 10% of maximum values. At larger solar zenith angles, the agreement was non-uniform with deviations explainable by insufficient correction functions. Comparison with previous calibrations for some j(O1D-FR indicated

  9. Synthesis and Flash Photolysis Studies of 1,3,3,2’-tetramethyl-9’-methoxy Indolinospironaphthoxazine

    Institute of Scientific and Technical Information of China (English)

    张新宇; 金声; 梁永超; 明阳福; FAN Mei-Gong

    1994-01-01

    A new spirooxazine,1,3,3,2′-tetramethy1-9′-methoxyspiro [-2H-indole-2,3′-[-3H] naphth[2,1-b] [-1,4′] oxazine] (Ⅰ) was synthesized.Its photochromic process was studied using nanosecond time-resolved absorption spectroscopy techniques.After irradiation of I with 248 nm laser pulse,a short-lived col-ored species with two absorption bands was observed.In cyclohexane the two bands appear at 470 nm and640 nm,while in acetonitrile at 460 nm and 670 nm.The kinetics for the decay of the colored species is first-order,and its lifetimes are 0.5 μs in cyclohexane and 1.3 μs in acetonitrile.From these results,this short-lived species is assumed to be an intramolecular charge-transfer (CT) intermediate instead of photomero-cyanines (PMC).No absorption band of PMC has been found.The phenomenoncan be interpreted by theproposed potential energy curve.

  10. Evaluating Non-In-Place Update Techniques for Flash-Based Transaction Processing Systems

    Science.gov (United States)

    Wang, Yongkun; Goda, Kazuo; Kitsuregawa, Masaru

    Recently, flash memory is emerging as the storage device. With price sliding fast, the cost per capacity is approaching to that of SATA disk drives. So far flash memory has been widely deployed in consumer electronics even partly in mobile computing environments. For enterprise systems, the deployment has been studied by many researchers and developers. In terms of the access performance characteristics, flash memory is quite different from disk drives. Without the mechanical components, flash memory has very high random read performance, whereas it has a limited random write performance because of the erase-before-write design. The random write performance of flash memory is comparable with or even worse than that of disk drives. Due to such a performance asymmetry, naive deployment to enterprise systems may not exploit the potential performance of flash memory at full blast. This paper studies the effectiveness of using non-in-place-update (NIPU) techniques through the IO path of flash-based transaction processing systems. Our deliberate experiments using both open-source DBMS and commercial DBMS validated the potential benefits; x3.0 to x6.6 performance improvement was confirmed by incorporating non-in-place-update techniques into file system without any modification of applications or storage devices.

  11. Studies on laser flash photolysis and pulse radiolysis of quinoline and some of its derivatives%喹啉及其衍生物的脉冲辐解和激光光解研究

    Institute of Scientific and Technical Information of China (English)

    ZHU Dazhang; WANG Shilong; SUN Xiaoyu; LI Wenzhe; ZENG Kailing; NI Yaming; WANG Wenfeng; YAO Side

    2005-01-01

    Quinoline and some of its derivatives were reported to be carcinogenic, toxic and mutagenic[1-3]. The widespread use of quinoline and its derivatives entails that these compounds are distributed in the environment, polluting soil and water together with many other environmental chemicals.Time-resolved laser flash photolysis and pulse radiolysis have been used to study the reaction of quinoline (Q), 2, 6-dimethyl-quinoline (DMQ) and isoquinoline (IQ) with hydrated electrons, hydroxyl radicals and hydrogen radicals. Transient absorption spectra were obtained and reaction rate constants to the reactions were determined, as showed in Table 1. Rossible mechanisms of the reactions were suggested.In addition, oxidization reactions of SO4·-, Br2·- and N3·- with isoquinoline, quinoline and its derivatives were studied. It showed that SO4- could oxidize quinoline, 2, 6-dimethylquinoline and isoquinoline; Br2·-could oxidize isoquinoline to its cation radicals, but it could not oxidize quinoline or 2, 6-diemethylquinoline; N3·- could oxidize none of them.With a better understandings on photolysis and radiolysis of isoquinoline, quinoline and its derivates, the study is of help for degradation of the chemicals and for environment protection.

  12. Photophysical Properties and Photoinduced Electron Transfer between [60]Fullerene-Containing Cyclic Sulphoxide [ C60-C6H8SO] and Tetrathiafulvalene (TTF) by Laser Flash Photolysis

    Institute of Scientific and Technical Information of China (English)

    ZENG,He-Ping(曾和平)

    2002-01-01

    Photoinduced electron transfer (PET) processes between C60-C6H8SO and Tetrathiafulvalene (TTF) have been studied by nanosecond laser photolysis. Quantum yields (φet) and rate constants of electron transfer (ket) from TTF to excited triplet state of [ 60 ] fullerene-containing cyclic sulphoxide in benzonitrile (BN) have been evaluated by observing the transient absorption bands in the NIR region. With the decay of excited triplet state of [ 60 ] fullerene-containing cyclic sulphoxide, the rise of radical anion of [60]fullerene-containing cyclic sulphoxide is observed.

  13. A Histogram-Based Static-Error Correction Technique for Flash ADCs

    Institute of Scientific and Technical Information of China (English)

    Armin Jalili; J Jacob Wikner; Sayed Masoud Sayedi; Rasoul Dehghani

    2011-01-01

    High-speed, high-accuracy data converters are attractive for use in most RF applications. Such converters allow direct conversion to occur between the digital baseband and the antenna. However, high speed and high accuracy make the analog components in a converter more complex, and this complexity causes more power to be dissipated than if a traditional approach were taken. A static calibration technique for flash analog-to-digital converters (ADCs) is discussed in this paper. The calibration is based onhistogram test methods, and equivalent errors in the flash ADC comparators are estimated in the digital domain without any significant changes being made to the ADC comparators. In the trimming process, reference voltages are adjusted to compensate for static errors. Behavioral-level simulations of a moderate-resolution 8-bit flash ADC show that, for typical errors, ADC performance is considerably improved by the proposed technique. As a result of calibration, the differential no.nlinearities (DNLs) are reduced on average from 4 LSB to 0.5 LSB, and the integral nonlinearities (INLs) are reduced on average from 4.2 LSB to 0.35 LSB. Implementation issues for this proposed technique are discussed in our subsequent paper, “A Histogram-Based Static-Error Correction Technique for Flash ADCs: Implementation Aspects. ”

  14. Laser photolysis-resonance fluorescence technique (LP-RF) applied to the study of reactions of atmospheric interest

    Science.gov (United States)

    Albaladejo, J.; Cuevas, C. A.; Notario, A.; Martínez, E.

    Atomic chlorine is highly reactive with a variety of organic and inorganic compounds so that relatively small concentrations can compete with the tropospheric oxidants (OH, O3 and NO3) in determining the tropospheric fate of such compounds [1]. Besides, there is a lot of evidence that bromine compounds play significant role in the ozone chemistry both in the troposphere and in the stratosphere [2]. In this work we show the laser photolysis-resonance fluorescence technique (LP-RF) applied to the study of gas phase reactions of halogen atoms with volatile organic compounds (VOCs) of interest in atmospheric chemistry [3]. By means of this technique is possible to measure the rate constants of theses reactions, and subsequently obtain the Arrhenius parameters. Halogens atoms are produced in a excess of the VOC and He, by photolyzing Cl2 at 308 nm to obtain Cl atoms, or CF2Br2 at 248 nm for Br atoms, both cases using a pulsed excimer laser. The radiation (135 nm) from a microwave-driven lamp, through which He containing a low concentrations of Cl2 or Br2 was flowed, was used to excite the resonance fluorescence from the corresponding halogen atom in the jacketed Pyrex reaction cell. Signal were obtained using photon-counting techniques in conjunction with multichannel scaling. The fluorescence signal from the PMT was processed by a preamplifier and sent to an multichannel scaler to collect the time-resolved signal. The multichannel scaler was coupled to a microcomputer for further kinetics analysis.

  15. Nanosecond Laser Photolysis of Opaque Heterogeneous Photosensitizers.

    Science.gov (United States)

    1987-10-01

    Willsher spent two weeks in Spain during the Summer working on this project and presented a poster at the XIIth Recunion Bienal de Quimica Organica de la...Real Sociedad Espaiola de Quimica , Cordoba, Spain,23-25 September, entitled "Fase Solida : Contribuci6n de la "Laser Flash Photolysis" a la Elucidacion

  16. A HistogramBased Static Error Correction Technique for Flash ADCs: Implementation

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    In this paper, we focus on practical issues in implementing a calibration technique for medium-resolution, highspeed flash analogtodigital converters (ADCs). In [1], we theoretically describ the calibration technique and perform a behaviorallevel simulation to test its functionality [1]. In this work, we discuss some issues in transistorlevel implementation. The predominant factors that contribute to static errors such as reference generator mismatch and trackandhold (T/H) gain error can be treated as inputreferred offsets of each comparator. Using the proposed calibration technique, these errors can be calibrated with minimal detriment to the dynamic performance of the converter. We simulate a transistorlevel implementation of a 5-bit, 1 GHz ADC in a 1.2 V, 65 nm CMOS process. The results show that DNL can be improved from 2.5 LSB to below 0.7 LSB after calibration, and INL can be improved from 1.6 LSB to below 0.6 LSB after calibration.

  17. Design and Fabrication of Edge Filter Using Absorbed ZnS Single Layer Prepared by Flash Evaporation Technique

    Science.gov (United States)

    Habubi, Nadir F.; Mishjil, Khudheir A.; Rashid, Hayfa G.; Mansour, H. L.

    Long-wave pass edge filter of high transmittance and wide bandpass have been designed and fabricated using on a single weakly absorbed ZnS thin film material of thickness of about 300 nm which was prepared by using the flash evaporation technique. The design was based on characteristic matrix theory, taking into account the effect of dispersion phenomena for all spectral wavelength.

  18. New logarithmic technique of diffusivity identification using the flash method; Nouvelle technique logarithmique d`identification de la diffusivite par la methode flash

    Energy Technology Data Exchange (ETDEWEB)

    Thermitus, M.A.; Laurent, M. [Institut National des Sciences Appliquees (INSA), 69 - Villeurbanne (France)

    1997-12-31

    Using a logarithmic transformation, the thermogram of a flash experiment can be interpreted as the sum of the adiabatic model solution with a term representative of the losses. Two methods based on this transformation are proposed in this study. They are based on the identification of a parameter that depends on the thickness of the sample and on its diffusivity and not on the experimental conditions. They allow to identify the diffusivity with a high precision even for materials with a low conductivity at high temperatures. (J.S.) 12 refs.

  19. Photophysical Properties and Photoinduced Electron Transfer between[60]Fullerene—containing Cyclic Sulphoxide [C60—C60H8SO]and Tetrathiafulvalene(TTF) by Laser Flash Photolysis

    Institute of Scientific and Technical Information of China (English)

    曾和平

    2002-01-01

    Photoinduced electron transfer(PET) processes between C60-C6H8SO and Tetrathiafulvalene(TTF) have been studied by nanosecond laser photolysis.Quantrm yiekds(φet) and rate constants of electron transfer(ket) from TTF to excited triplet state of[60] fullerene-containing cyclic sulphoxide in benzonitrile(BN) have been evaluated by observing the transient absorption bands in the NIR region.With the decay of excited triplet state of [60]fullerene-containing cyclic suplhoxide,the rise of radical anion of [60]fullerene-containing cyclic sulphoxinde is observed.

  20. Flash fluorescence with indocyanine green videoangiography to identify the recipient artery for bypass with distal middle cerebral artery aneurysms: operative technique.

    Science.gov (United States)

    Rodríguez-Hernández, Ana; Lawton, Michael T

    2012-06-01

    Distal middle cerebral artery (MCA) aneurysms frequently have nonsaccular morphology that necessitates trapping and bypass. Bypasses can be difficult because efferent arteries lie deep in the opercular cleft and may not be easily identifiable. We introduce the "flash fluorescence" technique, which uses videoangiography with indocyanine green (ICG) dye to identify an appropriate recipient artery on the cortical surface for the bypass, enabling a more superficial and easier anastomosis. Flash fluorescence requires 3 steps: (1) temporary clip occlusion of the involved afferent artery; (2) videoangiography demonstrating fluorescence in uninvolved arteries on the cortical surface; and (3) removal of the temporary clip with flash fluorescence in the involved efferent arteries on the cortical surface, thereby identifying a recipient. Alternatively, temporary clips can occlude uninvolved arteries, and videoangiography will demonstrate initial fluorescence in efferent arteries during temporary occlusion and flash fluorescence in uninvolved arteries during reperfusion. From a consecutive series of 604 MCA aneurysms treated microsurgically, 22 (3.6%) were distal aneurysms and 11 required a bypass. The flash fluorescence technique was used in 3 patients to select the recipient artery for 2 superficial temporal artery-to-MCA bypasses and 1 MCA-MCA bypass. The correct recipient was selected in all cases. The flash fluorescence technique provides quick, reliable localization of an appropriate recipient artery for bypass when revascularization is needed for a distal MCA aneurysm. This technique eliminates the need for extensive dissection of the efferent artery and enables a superficial recipient site that makes the anastomosis safer, faster, and less demanding.

  1. The Application of FLASH-3D Dynamic Contrast-enhanced Technique in Examination of Endometrial Carcinoma%FLASH-3D动态增强技术在子宫内膜癌检查中的应用

    Institute of Scientific and Technical Information of China (English)

    陈富珍; 杜立新; 梁超; 夏军; 李顶夫

    2014-01-01

    目的:探讨FLASH-3D动态增强技术在子宫内膜癌检查中的应用价值及术前分期中的作用。方法前瞻性的对2012年10月-2013年04月间具有完整临床资料及病理组织学证实的子宫内膜癌患者48例,在术前常规MRI检查的基础上,行FLASH-3D动态增强MRI扫描,分析宫壁及肿瘤的MRI动态增强特点,采用双盲法,将FLASH-3D动态增强对子宫内膜癌分期及判断肌层浸润深度的结果,与术后病理组织学FIGO结果对照。结果本组48例中,Ⅰ期34例(Ia22例,Ib12例),Ⅱ期9例,Ⅲ期3例,Ⅳ期2例。FLASH-3D动态增强序列分期准确性为81%(39/48),正确判断深肌层侵犯的敏感性为84%、特异性为90%、准确性为88%、与术后病理组织学结果对照,差异无显著意义(P>0.05)。结论 FLASH-3D动态增强技术在子宫内膜癌早期诊断和术前分期中具有重要作用,能显著提高判断肿瘤肌层浸润深度的准确性,为临床手术方式的选择和术后评估具有指导作用,有望成为女性盆腔肿瘤的常规检查方法。%Objective To investigate the application value and preoperative staging role of FLASH-3D dynamic contrast-enhanced technique in examination of endometrial carcinoma. Methods From October 2012 to April 2013, the prospective study included 48 patients with complete clinical data and pathologically confirmed endometrial carcinoma. After routine MRI examination, the subjects were underwent FLASH-3D (a fast low angle shot technique with three dimensional fat-suppressed angiographic sequences) dynamic contrast-enhanced examination. The dynamic enhancement features of uterine wall and tumors were analyzed respectively. With a double-blind manner,FLASH-3D preoperative staging and findings in assessing myometrial invasion were compared with the postoperative pathological results. Results 48 cases with pathologically-proven endometrial carcinoma were composed of 34 patients in stage I(Ia 22

  2. A novel technique for ultrasound-guided central venous catheterization under short-axis out-of-plane approach: "stepwise flashing with triangulation".

    Science.gov (United States)

    Horiuchi, Toshinori; Okuda, Chie; Kurita, Naoko; Yamaguchi, Ayako; Kitagawa, Kazuhiko; Takeda, Masafumi; Sha, Keiichi; Nagahata, Toshihiro

    2017-06-20

    In ultrasound-guided central venous catheterization, there is no standard technique either for the needle tip visualization or for the adequate needle angle and entry to the skin with short-axis view under out-of-plane technique. In the present study, we propose a novel technique named "stepwise flashing with triangulation", and the efficacy of this technique is assessed. Before and after a didactic session in which the technique was explained, 12 novice residents were asked to position the needle tip on or into the imitation vessels and to avoid deeper penetration by using an agar tissue phantom with ultrasound guidance. "Stepwise flashing" technique was for stepwise visualization of the needle tip, and "triangulation" technique was for adequate needle angle and entry to the skin. After the session, the success rate was increased and a deeper penetration rate was decreased. This technique will help us to facilitate vascular access and to avoid complications in clinical settings.

  3. Comparison of Vanillin and Isovanillin Photolysis in Aqueous Solutions

    Science.gov (United States)

    Vusovich, O. V.; Lapin, I. N.; Svetlichnyi, V. A.; Sul'timova, N. B.; Tchaikovskaya, O. N.

    2014-03-01

    General kinetic regularities of reactions of stationary and laser photolysis of 3-methoxy-4-hydroxybenzaldehyde (vanillin) and 3-hydroxy-4-methoxybenzaldehyde (isovanillin) are investigated by the method of nanosecond laser flash-photolysis. The 4th harmonic of a Nd:YAG laser (λexc = 266 nm) with pulse duration of 7 ns, output power of 100 MW/cm2, and delay time of 30 ns was used as an excitation source. As a result of photolysis, the same photoproducts are formed in the region of absorption at 715 nm. The rate constants of vanillin and isovanillin decomposition obey the first order law and are 2.3ṡ106 and 2.5ṡ106 s-1, respectively.

  4. Photoinduced Oxidation Reaction of Benzotrifluoride with OH Radical by the Laser Flash Method

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Ren-Xi; YE,Zhao-Lian; SHEN,Yan; DONG,Wen-Bo; HOU,Hui-Qi

    2008-01-01

    The optical transient and kinetics characterizations of the transients formed in the reaction of OH with benzotrifluoride (BTF) were performed by a laser flash photolysis technique. The results indicated that the formation of π-type adduct of C6H5(OH)CF3 was the major reaction channel, and the σ-type adduct of C6H5CF3OH formation was an additional minor process in the oxidation reaction of BTF attacked by OH radicals yielded from the photolysis of H2O2. Addition of OH to the CF3 group led to the fluoride ion elimination to yield α,α-difluorophenylcarbinol (C6H5CF2OH). Trifluoromethylphenol (HOC6H4CF3) of meta-, para- and ortho-substituted isomers resulted from the addition of OH to the BTF aromatic ring.

  5. 闪存数据库:现状、技术与展望%Flash-Based Database: Studies, Techniques and Forecasts

    Institute of Scientific and Technical Information of China (English)

    王江涛; 赖文豫; 孟小峰

    2013-01-01

    With the growing popularity of flash memory,flash has been widely used in various types of applications,such as mobile devices,PC machines,and servers.Flash,as a new type of storage media unlike disk,has its inherent properties which include non-volatility,high access speed,shock resistance,lower power,and high storage density etc.These properties,however,will bring new challenges for data management.Although disk-based database management system has the powerful ability for managing data,its current techniques cannot make full use of high I/O performance of flash memory if we transfer it to flash without modification.Therefore,it is a hot topic to design and implement flash-based database systems.In this survey,the new properties and translation layer of flash is introduced firstly.Secondly,several database critical techniques on buffer,index,query optimization,and transaction processing are surveyed and classified.Thirdly,we discuss some research issues on flash-based hybrid storage systems.At last,based on the analyzed problems,suggestions for future research works are put forward.%随着闪存存储技术的发展,闪存已经广泛应用于各种移动设备、PC机和服务器中.作为一种完全不同于磁盘的新型存储介质,闪存具有非易失、高速读写、抗震、低功耗、高存储密度等物理特性,这使得基于闪存的数据管理问题成为新的挑战.数据库系统是数据管理的重要技术,将现有的数据库系统直接移植到闪存上并不能充分发挥其硬件特性,设计实现基于闪存的数据库系统是当前的一个研究热点.文中介绍了闪存的特性和闪存转换层;总结了缓冲区、索引、查询和事务等数据库关键技术;讨论了基于闪存的混合存储数据管理.最后,基于该领域亟待解决的诸多问题,指出了未来的研究方向.

  6. Visible and infrared techniques for flash flood, hydrological, and agricultural applications

    Science.gov (United States)

    Scofield, R. A.

    1981-01-01

    A common requirement of these agriculture, climatology and hydrology fields is the accurate and timely estimation of precipitation. Yet, it is often difficult to obtain such estimates by conventional means. The advent of satellite remote sensing however has opened the possibility of making rain estimates over time and space scale never before available. A computer automated technique that estimates a summertime convective rainfall from the thermal infrared imagery of geosynchronous satellites is reviewed.

  7. Estimation of flash flood using surface water model and GIS technique in Wadi El Azariq, East Sinai, Egypt

    OpenAIRE

    Osta, Maged M.; Sabri, Mohamed Sh.; Masoud, Milad H.

    2016-01-01

    The study of flash flood hazard phenomenon and runoff potentialities are the major task of a hydrologists especially in arid and semi-arid regions. This paper presents a new approach to modeling flash floods in dryland catchments by the integration between physiographic features of the study basin, Geographic Information System (GIS) and Watershed Modelling System (WMS). Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER) data was used to prepare a digit...

  8. Magnetic, electrical and dielectric behaviour of Ni 0.8Zn 0.2Fe 2O 4 prepared through flash combustion technique

    Science.gov (United States)

    Mangalaraja, R. V.; Ananthakumar, S.; Manohar, P.; Gnanam, F. D.

    2002-12-01

    Nickel-zinc ferrites of composition Ni 0.8Zn 0.2Fe 2O 4 were prepared by flash combustion technique and sintered at various sintering temperatures such as 1150°C, 1250°C and 1350°C. Magnetic properties like hysteresis parameters, saturation magnetisation and Curie temperature were studied. Electrical properties namely AC-resistivity as a function of frequency and DC-resistivity as a function of temperature were studied for ferrite samples sintered at various temperatures. Dielectric properties such as dielectric constant, ɛ' and dielectric loss factor, tan δ were also studied for ferrite samples as a function of frequency. It is observed that Ni-Zn ferrites prepared by this method have AC-resistivity of the order 10 6-10 1 Ω cm for the frequency range from 1 kHz to 13 MHz and DC-resistivity of the order ⩾10 9 Ω cm is observed as the function of temperature from room temperature to 300°C. The resistivity obtained is higher than that of ferrites prepared by the conventional ceramic method. This is because of high purity, controlled microstructure and porosity of ferrites prepared by flash combustion technique. The dielectric constant and dielectric loss obtained for the ferrites prepared through this flash combustion technique possess lower value than that of the ferrites prepared by conventional ceramic method for the same composition. High resistivity and low dielectric behaviour make these ferrite materials useful in high frequency applications.

  9. Formation of hydroxyl radical from the photolysis of salicylic acid.

    Science.gov (United States)

    Zhou, Can-Hua; Cheng, Shi-Bo; Yin, Hong-Ming; He, Guo-Zhong

    2011-05-26

    Photodissociation dynamics of salicylic acid (SA) in the gas phase at different photolysis wavelengths (266, 315-317 nm) is investigated by probing the nascent OH photoproduct employing the single-photon laser-induced fluorescence (LIF) technique. At all the photolysis wavelengths it is found that the nascent OH radicals are produced mostly in a vibrationally ground state (υ'' = 0) and have similar rotational state distributions. The two spin-orbit and Λ-doublet states of the OH fragment formed in the dissociation are measured to have a nonstatistical distribution at each photolysis wavelength. The LIF signal of the OH could be observed upon photolysis at 317 nm but not at 317.5 nm. The threshold of OH formation from SA photodissociation is estimated to be 98.2 ± 0.9 kcal/mol. The effect of the phenolic OH group on the dissociation of SA is discussed.

  10. Identification of the reactive intermediates produced upon photolysis of p-azidoacetophenone and its tetrafluoro analogue in aqueous and organic solvents: implications for photoaffinity labeling.

    Science.gov (United States)

    Cline, Meredith R; Mandel, Sarah M; Platz, Matthew S

    2007-02-20

    Photolysis of p-azidoacetophenone (1a) or 2,3,5,6-tetrafluoro-p-azidoacetophenone (1b) releases the corresponding singlet nitrenes 2a and 2b. In aqueous solutions singlet nitrenes relax (1.1 ps and 43 ns, respectively) to the lower energy triplet nitrenes 3a and 3b, intermediates which do not react to form cross-links or adducts with typical amino acids and nucleic acids. In a hydrophobic environment singlet nitrene 2a partitions between forming triplet nitrene 3a and an acyl-substituted didehydroazepine 4a, which can be detected by LFP and time-resolved IR spectroscopy. The absolute rate constant of reaction of didehydroazepine 4a with water, in acetonitrile, was determined (3.5 x 10(4) M-1 s-1) by laser flash photolysis (LFP) techniques with IR detection at ambient temperature. Photolysis of tetrafluoro azide 1b releases singlet nitrene 2b, which has a lifetime of 172 ns in benzene and can readily be intercepted by pyridine to form ylide 10b (lambdamax = 415 nm). Singlet nitrene 2b reacts with the unactivated CH bonds of cyclohexane to form adduct 8b in 46% yield. Absolute rate constants of reaction of 1b with N-methylimidazole, phenol, dibutyl sulfide, indole, methanol, and dimethyl sulfoxide were determined using the pyridine ylide probe method. It is concluded that photolysis of p-azidoacetophenone (1a) will not lead to cross-link formation but that tetrafluorinated azide 1b can form useful singlet nitrene derived adducts upon photolysis.

  11. Aqueous photolysis of niclosamide

    Science.gov (United States)

    Graebing, P.W.; Chib, J.S.; Hubert, T.D.; Gingerich, W.H.

    2004-01-01

    The photodegradation of [14C]niclosamide was studied in sterile, pH 5, 7, and 9 buffered aqueous solutions under artificial sunlight at 25.0 A? 1.0 A?C. Photolysis in pH 5 buffer is 4.3 times faster than in pH 9 buffer and 1.5 times faster than in pH 7 buffer. In the dark controls, niclosamide degraded only in the pH 5 buffer. After 360 h of continuous irradiation in pH 9 buffer, the chromatographic pattern of the degradates was the same regardless of which ring contained the radiolabel. An HPLC method was developed that confirmed these degradates to be carbon dioxide and two- and four-carbon aliphatic acids formed by cleavage of both aromatic rings. Carbon dioxide was the major degradate, comprising 40% of the initial radioactivity in the 360 h samples from both labels. The other degradates formed were oxalic acid, maleic acid, glyoxylic acid, and glyoxal. In addition, in the chloronitroaniline-labeled irradiated test solution, 2-chloro-4-nitroaniline was observed and identified after 48 h of irradiation but was not detected thereafter. No other aromatic compounds were isolated or observed in either labeled test system.

  12. Simultaneous measurement of thermal diffusivity and effusivity of solids using the flash technique in the front-face configuration

    Science.gov (United States)

    Wilbur Pech-May, Nelson; Cifuentes, Ángel; Mendioroz, Arantza; Oleaga, Alberto; Salazar, Agustín

    2015-08-01

    Both thermal diffusivity and effusivity (or conductivity) are necessary to characterize the thermal transport properties of a material. The flash method is the most recognized procedure to measure the thermal diffusivity of free-standing opaque plates. However, it fails to simultaneously obtain the thermal effusivity (or conductivity). This is due to the difficulty of knowing the total energy absorbed by the sample surface after the light pulse. In this work, we propose using the flash method in the front-face configuration on a two-layer system made of the unknown plate and a fluid of known thermal properties. We demonstrate that the surface temperature is sensitive to the thermal mismatch between the plate and the fluid, which is governed by their thermal effusivity ratio. In order to verify the validity of the method and to establish its application limits we have performed flash measurements, using a pulsed laser and an infrared camera, on a set of calibrated materials (metals, alloys, ceramics and polymers) covering a wide range of thermal transport properties. These results confirm the ability of the flash method to simultaneously retrieve thermal diffusivity and effusivity in a fast manner in samples whose effusivities are lower than three times the effusivity of the liquid used as backing fluid.

  13. Document Flash Thermography

    OpenAIRE

    Larsen, Cory; Baker, Doran

    2011-01-01

    This paper presents an extension of flash thermography techniques to the analysis of documents. Motivation for this research is to develop the ability to reveal covered writings in archaeological artifacts such as the Codex Selden or Egyptian Cartonnage. An emphasis is placed on evaluating several common existing signal processing techniques for their effectiveness in enhancing subsurface writings found within a set of test documents. These processing techniques include: contrast stretching, ...

  14. Foundation Flash CS4 for Designers

    CERN Document Server

    Green, Tom

    2008-01-01

    In this book, you'll learn:* How to create effective animations using the new Motion Editor and animation tools * How to use the new 3D features to animate objects in 3D space * Best-practice tips and techniques from some of the top Flash practitioners on the planet * How to create captioned video and full-screen video, and deploy HD video using Flash * Techniques for using the Flash UI components as well as XML documents to create stunning,interactive presentations If you're a Flash designer looking for a solid overview of Flash CS4, this book is for you. Through the use of solid and practica

  15. PM-GCD - A combined IR-MW satellite technique for frequent retrieval of heavy precipitation: Application to the EU FLASH project

    Science.gov (United States)

    Casella, Daniele; Dietrich, Stefano; di Paola, Francesco; Formenton, Marco; Mugnai, Alberto; Sanò, Paolo

    2010-05-01

    Precipitation retrievals based on measurements from microwave (MW) radiometers onboard low-Earth-orbit (LEO) satellites can reach a high level of accuracy - and especially so, for deep convective precipitating systems. However, these observations do not provide a satisfactorily coverage of the rapid evolution of intense precipitating systems. As a result, the obtained precipitation retrievals are often of limited use for many important applications -- including support to authorities in activating flood alarms. To avoid this problem, several techniques have been developed that combine accurate MW estimates with frequent infrared (IR) observations from geosynchronous (GEO) satellites, such as the European Meteosat Second Generation (MSG). Within the European Union FP6 FLASH project, we have developed a new combined MW-IR technique for producing frequent precipitation retrievals from space (which we call PM-GCD technique). This technique uses passive-microwave (PM) retrievals in conjunction with the Global Convection Detection (GCD) technique that discriminates deep convective clouds within the GEO observations, based on the difference between the water vapor (6.2 μm ) and thermal-IR (10.8 μm ) channels. In essence, within the PM-GCD technique, deep convective areas are defined from MSG observations, then calibrated using MW-AMSU precipitation retrievals and finally propagated over time with a simple tracking algorithm. In this paper, we describe the PM-GCD technique and discuss the results of its application to a flood event that occurred on September 12-15, 2006 over the north-western Mediterranean coastal areas, and that has been selected for joint research by the EU FLASH and HYDRATE projects.

  16. 黑闪红锦花缎的染色技术%Staining technique of black flash red silk damask

    Institute of Scientific and Technical Information of China (English)

    崔浩然

    2013-01-01

    中性染料与直接耐晒染料以一浴一步法工艺染锦丝人丝锦花锻“黑闪红”风格,不仅底板(锦丝)、提花(人丝)黑红鲜明、光泽艳亮,染色牢度能达到要求,而且还具有突出的“节能、减排、增效”优势。%Silk damask“black flash red”style which is made of nylon yarn and rayon was obtained using one bath one step method with neutral dye and direct fast dye. The base plate (nylon yarn) and jacquard weave (rayon) exhibit bright midnight red and brilliant gloss, and color fastness can also meet the requirement. Additionally, this process presents prominent superiority such as energy conservation, emission reduction and synergism.

  17. THE ASSESSMENT OF ECONOMICAL LOSS CAUSED BY FLOODS AND FLASH-FLOODS BY USING COMPUTER TECHNIQUES. CASE STUDY: LOPĂTARI VILLAGE, SLĂNIC RIVER

    Directory of Open Access Journals (Sweden)

    COSTACHE R.

    2015-03-01

    Full Text Available The present study aims to provide an example of the assessment of economical loss caused by floods and flash-floods, by integrating GIS techniques of hydraulic and hydrological modelling. The case study was performed in Lopătari village, which is located in the upper area of Slănic River, one of the most affected areas by floods and flash-floods. The flood event produced on 29.V.2012 was considered in order to perform this study. Thus, a flood hydrograph was simulated by using software HEC-HMS 3.5, based on hourly precipitation data from Bisoca meteorological station from 29.V.2012. The peak discharge resulting from the hydrological modelling software was used in HEC-RAS 4.1 hydraulic modelling software in order to determine the extent of flooding band, the number of the affected elements and the local economical loss. Finally, 21 flooded buildings were identified and 550 m of affected road, the estimated economical damage being about 800,000 RON.

  18. Characterization of transient species in laser photolysis of aromatic amino acids using acetone as photosensitizer

    Institute of Scientific and Technical Information of China (English)

    宋钦华; 徐业平; 俞书勤; 陈从香; 马兴孝; 王文锋; 姚思德; 林念芸

    1999-01-01

    The photochemical processes of aromatic amino acids were investigated in aqueous solution using acetone as photosensitizer by KrF (248 nm) laser flash photolysis. Laser-induced transient species were characterized according to kinetic analysis and quenching experiments. The intermediates recorded were assigned to the excited triplet state of tryptophan, the radicals of tryptophan and tyrosine. The excited triplet state of tryptophan produced via a triplet-triplet excitation transfer and the radicals arising from electron transfer reaction has been identified. Neither electron transfer nor energy transfer between triplet acetone and phenylalanine can occur in photolysis of phenylalanine aqueous solution which contains acetone. Furthermore, triplet acetone-induced radical transformation: Trp/N-Tyr→Trp-Tyr/O was observed directly in photolysis of dipeptide (Trp-Tyr) aqueous solution containing acetone, and the transformation resulting from intramolecular electron transfer was suggested.

  19. Studying the activation of epithelial ion channels using global whole-field photolysis.

    Science.gov (United States)

    Almassy, Janos; Yule, David I

    2013-01-01

    The production of saliva by parotid acinar cells is stimulated by Ca(2+) activation of Cl(-) and K(+) channels located in the apical plasma membrane of these polarized cells. Here we provide a detailed description of a flash photolysis experiment designed to give a global and relatively uniform photorelease of inositol 1,4,5-trisphosphate (InsP(3)) or Ca(2+) from caged precursors (NPE-InsP(3) or NP-EGTA) combined with the simultaneous measurement of whole-cell Ca(2+)-activated currents. The photolysis light source can be either an ultraviolet (UV) flash lamp or alternatively the output from a 375-nm diode laser, which is defocused to illuminate the entire field.

  20. Photolysis of alpha-azidoacetophenones: direct detection of triplet alkyl nitrenes in solution.

    Science.gov (United States)

    Singh, Pradeep N D; Mandel, Sarah M; Robinson, Rachel M; Zhu, Zhendong; Franz, Roberto; Ault, Bruce S; Gudmundsdóttir, Anna D

    2003-10-17

    We report the first detection of triplet alkyl nitrenes in fluid solution by laser flash photolysis of alpha-azido acetophenone derivatives, 1. Alphazides 1 contain an intramolecular triplet sensitizer, which ensures formation of the triplet alkyl nitrene by bypassing the singlet nitrene intermediate. At room temperature, azides 1 cleave to form benzoyl and methyl azide radicals in competition with triplet energy transfer to form triplet alkyl nitrene. The major photoproduct 3 arises from interception of the triplet alkyl nitrene with benzoyl radicals. The triplet alkyl nitrene intermediates are also trapped with molecular oxygen to yield the corresponding 2-nitrophenylethanone. Laser flash photolysis of 1 reveals that the triplet alkyl nitrenes have absorption around 300 nm. The triplet alkyl nitrenes were further characterized by obtaining their UV and IR spectra in argon matrices. (13)C and (15)N isotope labeling studies allowed us to characterize the C-N stretch of the nitrene intermediate at 1201 cm(-)(1).

  1. Physics Flash December 2016

    Energy Technology Data Exchange (ETDEWEB)

    Kippen, Karen Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). ADEPS Communications

    2016-12-01

    This is the December 2016 issue of Physics Flash, the newsletter of the Physics Division of Los Alamos National Laboratory (LANL). In this issue, the following topics are covered: Novel liquid helium technique to aid highly sensitive search for a neutron electrical dipole moment; Silverleaf: Prototype Red Sage experiments performed at Q-site; John L. Kline named 2016 APS Fellow; Physics students in the news; First Entropy Engine quantum random number generator hits the market; and celebrating service.

  2. Flash Sintering of Alumina-based Ceramics

    OpenAIRE

    Biesuz, Mattia

    2017-01-01

    Flash sintering is an electrical field-assisted consolidation technology and represents a very novel technique for producing ceramic materials, which allows to decrease sensibly both processing temperature and time. Starting from 2010, when flash sintering was discovered, different ceramic materials with a wide range of electrical properties have been successfully densified. Up to date, the research on flash sintering has been mainly focused on ionic and electronic conductors and on semicondu...

  3. Functional MR imaging of visual and motor cortex stimulation at high temporal resolution using a FLASH technique on a standard 1.5 Tesla scanner.

    Science.gov (United States)

    Wiener, E; Schad, L R; Baudendistel, K T; Essig, M; Müller, E; Lorenz, W J

    1996-01-01

    Functional magnetic resonance imaging (fMRI) was performed on a conventional 1.5 T scanner by means of a modified FLASH-technique at temporal resolutions of 80 and 320 ms. The method's stability was assessed by phantom measurements and by investigation of three volunteers resulting in a low amplitude (3%) periodic (4 s) signal modulation for the in vivo measurements, which was not observable in the phantom experiments. fMRI activation studies of motor and visual cortices of four adjacent slices were carried out on 12 healthy right-handed volunteers. Stimulation was performed by a triggered single white light flash or single finger-to-thumb opposition movement, respectively. Event-related response of visual and motor activation was traced over 10.24 s with a temporal resolution of 320 ms for the four slice measurements. Brain activation maps were calculated by correlation of measured signal time course with a time-shifted boxcar function. Activation was quantified by calculation of percentual signal change in relation to the baseline. Observed signal magnitudes were about 5-7% in visual and about 8-12% in primary motor cortex. While photic response was delayed by about 2 s, motor stimulation showed an instantaneous increase of the MR signal. MR signal responses for both stimuli had decayed completely after about 5 s. Our results show that event-related fMRI enables mapping of brain function at sufficient spatial resolution with a temporal resolution of up to 80 ms on a conventional scanner.

  4. The Application of ActionScript3.0 and XML Techniques in Pure Flash Website%纯FLASH网站中ActionScript3.0与XML的结合应用

    Institute of Scientific and Technical Information of China (English)

    钱晶; 杨建明

    2014-01-01

    该文阐述了在纯Flash网站中通过ActionScript3.0与XML技术的结合应用实现Flash与ASP或PHP等文件的跨平台交流,从而开发功能完整的动态网页。%This paper stated the application of ActionScript3.0 and XML techniques in pure Flash web site to implement the cross-platform interchange between Flash and ASP or PHP files for the development of full function active web pages.

  5. Quantum yields for OH production from 193 and 248 nm photolysis of HNO3 and H2O2

    Science.gov (United States)

    Schiffman, A.; Nelson, D. D., Jr.; Nesbitt, D. J.

    1993-05-01

    Flash kinetic spectroscopy in a flow tube is used to measure at room temperature the absolute yields for OH production from 193 and 248 nm photolysis of HNO3 and H2O2. The OH radicals are produced by excimer laser photolysis and probed via direct absorption of high resolution tunable IR laser light. The results indicate quantum yields for both precursors at both wavelengths which are less than the maximum possible values of 1 for H2O2. The present measurements are discussed in light of contrasting results suggested from other work.

  6. Kinetics of Hydrolysis and Products of Hydrolysis and Photolysis of Tetryl.

    Science.gov (United States)

    1984-10-22

    NSWC TR 84-88 Lfl KINETICS OF HYDROLYSIS AND PRODUCTS OF HYDROLYSIS AND PHOTOLYSIS OF TETRYL BY ELEONORE G. KAYSER NICHOLAS E. BURLINSON DAVID H...PHOTOLYSIS OF TETRYL Feb 1980 to Dec 1981 S.PERFORMING ORG. REPORT NUMBER 7. AU THOR(s) SCONTRACT OR GRANT NUMUER11110 Eleonore G. Kayser, NLchcolas E...Library 1 Monitoring Techniques Division Dr. Ron Spanggord I Attn: RD680 (Robert B. Medz) 1 333 Rcvenswood Avenue Washington, DC 20460 Menlo Park

  7. Kinetics and magnetic field effect in geminate recombination of triplet radical pairs adsorbed onto porous glass studied by laser flash technique

    Science.gov (United States)

    Levin, P. P.; Katalnikov, I. V.; Kuzmin, V. A.

    1991-07-01

    Geminate recombination kinetics of radical pairs (RP) formed by electron or hydrogen atom transfer from triphenylamine, tri(4-bromophenyl)amine, 4-phenylaniline or 4-phenylphenol to triplet 9,10-anthraquinone, benzophenone or 4-bromobenzophenone both adsorbed onto an optically transparent SiO 2 porous glass have been studied, using the laser flash technique with spectrophotometric registration. The kinetics are adequately described by the sum of two exponentials, ascribed to the existence of different kinds of "supercages" on the surface. At the same time, the simplest approximation by only one exponential is fair in many cases, because the contribution of a "slow" exponential is comparatively low and is masked by the slow component because of the decay of the escaped radicals. Introduction of a heavy Br atom leads to the acceleration of the geminate recombination; application of an external magnetic field results in retardation. The heavy-atom effect displays the contribution of the intersystem backwards electron transfer or intersystem recombination in the contact states of a triplet RP owing to the spin-orbit coupling. The magnetic field effect is the result of the significant contribution of the recombination route through the separated RP, where the hyperfine coupling and relaxation mechanisms of the RP spin evolution are active.

  8. Structural and optical properties of Sn{sub 1−x}Fe{sub x}O{sub 2} thin films prepared by flash evaporation technique

    Energy Technology Data Exchange (ETDEWEB)

    Kuppan, M., E-mail: skaleemulla@gmail.com; Kaleemulla, S., E-mail: skaleemulla@gmail.com; Rao, N. Madhusudhana, E-mail: skaleemulla@gmail.com; Krishna, N. Sai, E-mail: skaleemulla@gmail.com; Begam, M. Rigana, E-mail: skaleemulla@gmail.com [Thin Films Laboratory, School of Advanced Sciences, VIT University, Vellore-632014, Tamilnadu (India)

    2014-04-24

    Sn{sub 1−x}Fe{sub X}O{sub 2} (x = 0, 0.05) thin films were prepared on glass substrate using the flash evaporation technique. The samples were annealed at 773 K for 2 hrs in air atmosphere. A systematic study was carried out on the structural and optical properties of the as deposited and annealed thin films. From the X-ray diffraction analysis it was found that the Sn{sub 1−x}Fe{sub X}O{sub 2} films deposited at 623 K were amorphous in nature and the Sn{sub 1−x}Fe{sub X}O{sub 2} films annealed at 773 K exhibited the tetragonal structure of the SnO{sub 2}. The optical band gap of the SnO{sub 2} thin films was found to be as 3.17 eV whereas the optical band gap of the Sn{sub 1−x}Fe{sub X}O{sub 2} films was found to be as 3.01 eV after air annealing.

  9. Radar rainfall estimation for the post-event analysis of a Slovenian flash-flood case: application of the mountain reference technique at C-band frequency

    Directory of Open Access Journals (Sweden)

    L. Bouilloud

    2009-01-01

    Full Text Available This article is dedicated to radar rainfall estimation for the post-event analysis of a Slovenian flash flood that occurred on 18 September 2007. The utility of the Mountain Reference Technique is demonstrated to quantify rain attenuation effects that affect C-band radar measurements in heavy rain. Maximum path-integrated attenuation between 15 and 20 dB were measured thanks to mountain returns for path-averaged rain rates between 10 and 15 mm h−1 over a 120-km path. The proposed technique allowed estimation of an effective radar calibration correction factor, assuming the reflectivity-attenuation relationship to be known. Screening effects were quantified using a geometrical calculation based on a digitized terrain model of the region. The vertical structure of the reflectivity was modelled with a normalized apparent vertical profile of reflectivity. Implementation of the radar data processing indicated that: (1 attenuation correction using the Hitschfeld Bordan algorithm allowed obtaining satisfactory radar rain estimates (Nash criterion of 0.8 at the event time scale; (2 due to the attenuation equation instability, it is however compulsory to limit the maximum path-integrated attenuation to be corrected to about 10 dB; (3 the results also proved to be sensitive on the parameterization of reflectivity-attenuation-rainrate relationships. The convective nature of the precipitation explains the rather good performance obtained. For more contrasted rainy systems with convective and stratiform regions, the combination of the vertical (VPR and radial (attenuation, screening sources of heterogeneity yields a still very challenging problem for radar quantitative precipitation estimation at C-band.

  10. Photolysis of a Benzyne Precursor Studied by Time-Resolved FTIR Spectroscopy.

    Science.gov (United States)

    Torres-Alacan, Joel

    2016-02-01

    The 266 nm laser flash photolysis of phtaloyl peroxide (2) in liquid acetonitrile solution at room temperature has been investigated. Upon 266 nm laser irradiation, 2 is effectively photodecarboxylated leading to the formation of o-benzyne (1) and two equivalents of CO2, yet a small fraction of photolyzed 2 follows a different pathway leading to 6-oxocyclohexa-2,4-dienylideneketene (3) and one equivalent of CO2. Compound 3 is kinetically reactive and reacts in the microsecond time scale following a first-order kinetic law. The presence of 1 in the photolysis experiment is confirmed by trapping experiments with methyl 1-methylpyrrole-2-carboxylate (6). The Diels-Alder reaction between 1 and 6 occurs under the selected experimental conditions on a time scale shorter than 100 ms.

  11. Foundation Flash Catalyst

    CERN Document Server

    Goralski, Greg

    2010-01-01

    This book offers an introduction to Flash Catalyst for designers with intermediate to advanced skills. It discusses where Catalyst sits within the production process and how it communicates with other programs. It covers all of the features of the Flash Catalyst workspace, teaching you how to create designs from scratch, how to build application designs and add functionality, and how to master the Catalyst/Flex workflow. * Introduces Flash Catalyst * Focuses on production process * Covers the interrelation between Flash Catalyst and Photoshop/Illustrator/Flex/Flash What you'll learn Starting f

  12. Flash sintering of ceramic materials

    Science.gov (United States)

    Dancer, C. E. J.

    2016-10-01

    During flash sintering, ceramic materials can sinter to high density in a matter of seconds while subjected to electric field and elevated temperature. This process, which occurs at lower furnace temperatures and in shorter times than both conventional ceramic sintering and field-assisted methods such as spark plasma sintering, has the potential to radically reduce the power consumption required for the densification of ceramic materials. This paper reviews the experimental work on flash sintering methods carried out to date, and compares the properties of the materials obtained to those produced by conventional sintering. The flash sintering process is described for oxides of zirconium, yttrium, aluminium, tin, zinc, and titanium; silicon and boron carbide, zirconium diboride, materials for solid oxide fuel applications, ferroelectric materials, and composite materials. While experimental observations have been made on a wide range of materials, understanding of the underlying mechanisms responsible for the onset and latter stages of flash sintering is still elusive. Elements of the proposed theories to explain the observed behaviour include extensive Joule heating throughout the material causing thermal runaway, arrested by the current limitation in the power supply, and the formation of defect avalanches which rapidly and dramatically increase the sample conductivity. Undoubtedly, the flash sintering process is affected by the electric field strength, furnace temperature and current density limit, but also by microstructural features such as the presence of second phase particles or dopants and the particle size in the starting material. While further experimental work and modelling is still required to attain a full understanding capable of predicting the success of the flash sintering process in different materials, the technique non-etheless holds great potential for exceptional control of the ceramic sintering process.

  13. Direct photolysis and photocatalytic degradation of 2-amino-5-chloropyridine

    Directory of Open Access Journals (Sweden)

    BILJANA F. ABRAMOVIC

    2003-12-01

    Full Text Available The direct photolysis and photocatalytic degradation of a pyridine pesticide analogue, 2-amino-5-chloropyridine, were investigated employing different analytical techniques – potentiometry, for monitoring the pH and chloride generation, spectrophotometry, for studying the degradation of the pyridine moiety, ion chromatography, for monitoring nitrate formation, and total organic carbon analysis for investigating the efficiency of the process. The photocatalytic degradation was studied in aqueous suspensions of titanium dioxide under illumination by UV light. It was found that chloride evolution was a zero-order reaction which takes place by direct photolysis, in that way differing from the degradation of the pyridine moiety, which takes place in the presence of titanium dioxide. Changes in pH during degradation indicate the formation of acidic intermediates and nitrate in addition to chloride. The effect of the initial substrate concentration was also investigated by monitoring the reaction of chloride generation as well as the degradation reaction of the pyridine moiety. It was found that degradation of the parent compound (2.5 mmol/dm3 by direct photolysis is completed in about 20 minutes, and of the pyridine moety by photocatalytic degradation in about nine hours. Based on the obtained data a possible reaction mechanism is proposed.

  14. Inhibition of Neutral red photolysis with different antioxidants.

    Science.gov (United States)

    Rimpapa, Zlatan; Sofić, Emin; Sapcanin, Aida; Toromanović, Jasmin; Tahirović, Ismet

    2007-02-01

    Neutral red is a dye the azine structure which has been used as an acido-base indicator and a dye in histochemistry. In 1960 Goldhaber introduced Neutral red into the medium of resorbing bone cultures to localize the osteoclast in the living cultures. Using time-lapse microcinematography in order to follow the osteoclasts, he reported excellent contrast could be obtained with Neutral red due to the avidity of osteoclasts for this dye. Unfortunately, however, the photodynamic effect resulting from subsequent exposure of these cultures to light precluded this approach, and again in 1963. it was observed that the death of the osteoclasts was probably due to a photodynamic effect related to the dye in the cell, the presence of oxygen and the frequent exposure of light by our time-lapse photography. VIS and UV irradiation induced photolysis of Neutral red, and from Neutral red cation produced with photons a Neutral red radical. This Neutral red radical can be inhibited with action of an antioxidant, such as melatonin, glutathione, ascorbic acid, E vitamin, etc. We developed an assay with Neutral red photolysis which utilizes a VIS and UV irradiation technique for quantification the inhibition of photolysis with action of an antioxidant. In this method Neutral red acts double, as a free radical generator and as a photosensitizer.

  15. Laser photolysis of interaction of poly-guanylic acid (5′) with anthraquinone-2-sulfonate

    Institute of Scientific and Technical Information of China (English)

    马建华; 林维真; 王文峰; 韩镇辉; 姚思德; 林念芸

    2002-01-01

    The electron transfer reaction between triplet anthraquinone-2-sulfonate and poly- guanylic acid (5′) in CH3CN-H2O (97:3) has been investigated by 248 nm (KrF) laser flash photolysis. The transient absorption spectra and kinetics obtained from the interaction of triplet anthraquinone-2-sulfonate and poly[G] demonstrate that the primary ionic radical pair, radical cation of poly[G] and radical anion of anthraquinone-2-sulfonate have been detected simultaneously. The free energy changes in the process of the electron transfer were also calculated.

  16. Laser photolysis of interaction of poly-guanylic acid (5’) with anthraquinone-2-sulfonate

    Institute of Scientific and Technical Information of China (English)

    马建华; 韩镇辉; 林维真; 姚思德; 王文峰; 林念芸

    2002-01-01

    The electron transfer reaction between triplet anthraquinone-2-sulfonate and poly-guanylic acid (5’) in CH3CN-H2O (97 : 3) has been investigated by 248 nm (KrF) laser flash photolysis. The transient absorption spectra and kinetics obtained from the interaction of triplet anthraquinone-2-sulfonate and poly[G] demonstrate that the primary ionic radical pair, radical cation of poly[G] and radical anion of anthraquinone-2-sulfonate have been detected simultaneously. The free energy changes in the process of the electron transfer were also calculated.

  17. The flash-lag effect and the flash-drag effect in the same display.

    Science.gov (United States)

    Murai, Yuki; Murakami, Ikuya

    2016-09-01

    Visual motion distorts the perceived position of a stimulus. In the flash-drag effect (FDE), the perceived position of a flash appears to be shifted in the direction of nearby motion. In the flash-lag effect (FLE), a flash adjacent to a moving stimulus appears to lag behind. The FLE has been explained by several models, including the differential latency hypothesis, that a moving stimulus has a shorter processing latency than a flash does. The FDE even occurs when the flash is presented earlier than the moving stimulus, and it has been discussed whether this temporal property can be explained by the differential latency model. In the present study, we simultaneously quantified the FDE and FLE using the random jump technique (Murakami, 2001b) and compared their temporal properties. While the positional offset between a randomly jumping stimulus and a flashed stimulus determined the FLE, a drifting grating appeared next to the flash at various stimulus-onset asynchronies to induce the FDE. The grating presented up to 200 ms after the flash onset induced the FDE, whose temporal tuning was explained by a simple convolution model incorporating stochastic fluctuations of differential latency estimated from the FLE data and a transient-sustained temporal profile of motion signals. Thus, a common temporal mechanism to compute the stimulus position in reference to surrounding stimuli governs both the FDE and the FLE.

  18. Statistical Evolution of the Lightning Flash

    Science.gov (United States)

    Zoghzoghy, F. G.; Cohen, M.; Said, R.; Inan, U. S.

    2012-12-01

    Natural lightning is one of the most fascinating and powerful electrical processes on Earth. To date, the physics behind this natural phenomenon are not fully understood, due primarily to the difficulty of obtaining measurements inside thunderstorms and to the wide range of timescales involved (from nanoseconds to seconds). Our aim is to use accurate lightning geo-location data from the National Lightning Detection Network (NLDN) to study statistical patterns in lightning, taking advantage of the fact that millions of lightning flashes occur around the globe every day. We present two sets of results, one involving the patterns of flashes in a storm, and a second involving the patterns of strokes in a flash. These patterns can provide a surrogate measure of the timescales and the spatial extents of the underlying physical processes. First, we study the timescales of charge buildup inside thunderstorms. We find that, following a lightning flash, the probability of another neighboring flash decreases and takes tens of seconds to recover. We find that this suppression effect is a function of flash type, stroke peak current, cloud-to-ground (CG) stroke multiplicity, and other lightning and geographical parameters. We find that the probabilities of subsequent flashes are more suppressed following oceanic lightning, or following flashes with higher peak currents and/or higher multiplicities (for CG flashes). Second, we use NLDN data to study the evolution of the strokes within a CG flash. A CG flash typically includes multiple return strokes, which can occur in the same channel or in multiple channels within a few kilometers. We cluster NLDN stroke data into flashes and produce the probability density function of subsequent strokes as a function of distance and time-delays relative to the previous stroke. Using this technique, we investigate processes which occur during the CG lightning flash with nanosecond to millisecond timescales. For instance, our results suggest

  19. NAND flash memory technologies

    CERN Document Server

    Aritome, Seiichi

    2016-01-01

    This book discusses basic and advanced NAND flash memory technologies, including the principle of NAND flash, memory cell technologies, multi-bits cell technologies, scaling challenges of memory cell, reliability, and 3-dimensional cell as the future technology. Chapter 1 describes the background and early history of NAND flash. The basic device structures and operations are described in Chapter 2. Next, the author discusses the memory cell technologies focused on scaling in Chapter 3, and introduces the advanced operations for multi-level cells in Chapter 4. The physical limitations for scaling are examined in Chapter 5, and Chapter 6 describes the reliability of NAND flash memory. Chapter 7 examines 3-dimensional (3D) NAND flash memory cells and discusses the pros and cons in structure, process, operations, scalability, and performance. In Chapter 8, challenges of 3D NAND flash memory are dis ussed. Finally, in Chapter 9, the author summarizes and describes the prospect of technologies and market for the fu...

  20. Optical Flashes Preceding GRBs

    CERN Document Server

    Paczynski, B

    2001-01-01

    Only one optical flash associated with a gamma-ray burst has been detected so far by ROTSE. There are also upper limits obtained by several groups for several bursts. Recent model calculations indicate a possibility that optical flash may precede the GRB. Such flashes are undetectable in the currently popular observing mode, with optical instruments responding to GRB triggers. There is a need to develop all sky optical monitoring system capable of recognizing flashes in real time, and more powerful instruments that could respond robotically to optical triggers and carry out follow up observations.

  1. Pro Android Flash

    CERN Document Server

    Chin, Stephen; Campesato, Oswald

    2011-01-01

    Did you know you can take your Flash skills beyond the browser, allowing you to make apps for Android, iOS and the BlackBerry Tablet OS? Build dynamic apps today starting with the easy-to-use Android smartphones and tablets. Then, take your app to other platforms without writing native code. Pro Android Flash is the definitive guide to building Flash and other rich Internet applications (RIAs) on the Android platform. It covers the most popular RIA frameworks for Android developers - Flash and Flex - and shows how to build rich, immersive user experiences on both Android smartphones and tablet

  2. A highly reliable copper nanowire/nanoparticle ink pattern with high conductivity on flexible substrate prepared via a flash light-sintering technique.

    Science.gov (United States)

    Joo, Sung-Jun; Park, Sung-Hyeon; Moon, Chang-Jin; Kim, Hak-Sung

    2015-03-18

    In this work, copper nanowires (NWs) and Cu nanoparticles (NPs) were employed to increase the reliability of a printed electrode pattern under mechanical bending fatigue. The fabricated Cu NW/NP inks with different weight fractions of Cu NWs were printed on a polyimide substrate and flash light-sintered within a few milliseconds at room temperature under ambient conditions. Then, 1000 cycles of outer and inner bending fatigue tests were performed using a lab-made fatigue tester. The flash light-sintered Cu NW/NP ink film with 5 wt % Cu NWs prepared under the flash light-sintering conditions (12.5 J·cm–2 irradiation energy, 10 ms pulse duration, and one pulse) showed a lower resistivity (22.77 μΩ·cm) than those of the only Cu NPs and Cu NWs ink (94.01 μΩ·cm and 104.15 μΩ·cm, respectively). In addition, the resistance change (ΔR·R0(–1)) of the 5 wt % Cu NWs Cu NW/NP film was greatly enhanced to 4.19 compared to the 92.75 of the Cu NPs film obtained under mechanical fatigue conditions over 1000 cycles and an outer bending radius of 7 mm. These results were obtained by the densification and enhanced mechanical flexibility of flash light-sintered Cu NW/NP network, which resulted in prevention of crack initiation and propagation. To characterize the Cu NW/NP ink film, X-ray diffraction and scanning electron microscopy were used.

  3. Small-scale (flash) flood early warning in the light of operational requirements: opportunities and limits with regard to user demands, driving data, and hydrologic modeling techniques

    Science.gov (United States)

    Philipp, Andy; Kerl, Florian; Büttner, Uwe; Metzkes, Christine; Singer, Thomas; Wagner, Michael; Schütze, Niels

    2016-05-01

    In recent years, the Free State of Saxony (Eastern Germany) was repeatedly hit by both extensive riverine flooding, as well as flash flood events, emerging foremost from convective heavy rainfall. Especially after a couple of small-scale, yet disastrous events in 2010, preconditions, drivers, and methods for deriving flash flood related early warning products are investigated. This is to clarify the feasibility and the limits of envisaged early warning procedures for small catchments, hit by flashy heavy rain events. Early warning about potentially flash flood prone situations (i.e., with a suitable lead time with regard to required reaction-time needs of the stakeholders involved in flood risk management) needs to take into account not only hydrological, but also meteorological, as well as communication issues. Therefore, we propose a threefold methodology to identify potential benefits and limitations in a real-world warning/reaction context. First, the user demands (with respect to desired/required warning products, preparation times, etc.) are investigated. Second, focusing on small catchments of some hundred square kilometers, two quantitative precipitation forecasts are verified. Third, considering the user needs, as well as the input parameter uncertainty (i.e., foremost emerging from an uncertain QPF), a feasible, yet robust hydrological modeling approach is proposed on the basis of pilot studies, employing deterministic, data-driven, and simple scoring methods.

  4. Flash-Type Discrimination

    Science.gov (United States)

    Koshak, William J.

    2010-01-01

    This viewgraph presentation describes the significant progress made in the flash-type discrimination algorithm development. The contents include: 1) Highlights of Progress for GLM-R3 Flash-Type discrimination Algorithm Development; 2) Maximum Group Area (MGA) Data; 3) Retrieval Errors from Simulations; and 4) Preliminary Global-scale Retrieval.

  5. 激光雷达技术在河南栾川县山洪灾害调查中的示范应用%Application of laser radar technique in flash flood disaster investigation in Luanchuan County

    Institute of Scientific and Technical Information of China (English)

    张琦建; 刘昌军; 唐学哲; 孙涛; 郭良

    2015-01-01

    In recent years, the airborne Lidar is widely applied due to its ability to quickly obtain the third degree ground terrain information with efficiency and accuracy. Using UAV laser radar measurement technique, this research acquired flash flood data in two typical smal watersheds of Luanchuan County and introduced the process of the technique. Considering requirements of flash flood disaster evaluations, this paper detailed various methods including classification of laser point cloud data, DEM production, data processing technique of river cross-sections, and key technology of the automatic extraction of houses location and elevation. UAV laser radar technology features rapid data acquisition speed and high precision; it can meet the requirements of flash flood disaster investigations and provides the application demonstration of this technology. Consequently, this technique wil play an important role in investigation of flash flood disasters and have great application prospect.%机载LiDAR技术获取地面三维地物信息快捷、高效,近年来发展迅速,应用广泛。介绍了无人机雷达技术的航测技术流程,结合山洪灾害调查评价的应用需求,论述了激光点云数据的分类方法,数字高程模型(DEM)制作方法,河道断面批处理方法,居民户位置和高程的自动提取方法等应用关键技术,并以栾川县2个山洪灾害典型小流域为例,开展了示范应用。研究表明,无人机激光雷达测量技术获取数据速度快、精度高,能够满足山洪灾害调查的工作要求,为全国无资料地区山洪灾害调查工作提供了新技术的应用示范,将在全国山洪灾害调查工作中发挥巨大作用,具有较大的应用前景。

  6. UV photolysis for accelerating pyridine biodegradation.

    Science.gov (United States)

    Zhang, Yongming; Chang, Ling; Yan, Ning; Tang, Yingxia; Liu, Rui; Rittmann, Bruce E

    2014-01-01

    Pyridine, a nitrogen-containing heterocyclic compound, is slowly biodegradable, and coupling biodegradation with UV photolysis is a potential means to accelerate its biotransformation and mineralization. The initial steps of pyridine biodegradation involve mono-oxygenation reactions that have molecular oxygen and an intracellular electron carrier as cosubstrates. We employed an internal circulation baffled biofilm reactor for pyridine biodegradation following three protocols: direct biodegradation (B), biodegradation after photolysis (P+B), and biodegradation with succinic acid added (B+S). Succinic acid was the main UV-photolysis product from pyridine, and its catabolic oxidation generates internal electron carriers that may accelerate the initial steps of pyridine biodegradation. Compared with direct biodegradation of pyridine (B), the removal rate for the same concentration of photolyzed pyridine (P+B) was higher by 15 to 43%, depending on the initial pyridine concentrations (increasing through the range of 130 to 310 mg/L). Adding succinic acid alone (B+S) gave results similar to P+B, which supports that succinic acid was the main agent for accelerating the pyridine biodegradation rate. In addition, protocols P+B and B+S were similar in terms of increasing pyridine mineralization over 10 h: 84% and 87%, respectively, which were higher than with protocol B (72%). The positive impact of succinic acid-whether added directly or produced via UV photolysis-confirms that its catabolism, which produced intracellular electron carriers, accelerated the initial steps of pyridine biotransformation.

  7. Understanding Green Flashes

    Science.gov (United States)

    Young, Andrew T.

    1998-05-01

    Most astronomers learn about green flashes from either Minnaert's old book (Dover, 1954) or O'Connell's ``The Green Flash....'' Both have defects. Minnaert's account mostly represents what was known in the 1920s; it repeats Mulder's 3-fold classification, which omits Joule's second type of flash --- the one most commonly seen from mountain observatories. O'Connell searched only the astronomical literature, missing Dietze's crucially important paper (Z.f.Met. 9, 169 (1955)) showing that the ``textbook'' mechanism cannot produce flashes visible to the naked eye. He also erred in thinking that distortions of the setting Sun arise in the upper atmosphere (they are due to the marine boundary layer), and copied an error from Feenstra Kuiper's thesis that misidentified a common mirage-like phenomenon as Wegener's ``blank strip'' (Young et al., Appl. Opt. 36, 2689 (1997).) Most phenomena shown in O'Connell's book are caused by inversion layers below eye level, not above as in Wegener's phenomenon. The two commonest forms of green flash are associated with the inferior mirage and the mock mirage, corresponding to Fisher's Type A and Type B sunsets, respectively. Superrefraction, advocated by Wood and by Rayleigh as the cause of large flashes, actually suppress them: the airmass is proportional to the refraction (by Laplace's extinction theorem), so no green is transmitted when refraction is much larger than average. Although there is a physical green flash that can be photographed, the colors seen at sunset are strongly modified by bleaching of the L cones. Most ``green'' sunset flashes are actually yellow. Writers should stop representing Jules Verne's ``ancient legend'' as fact, as it was invented by Verne as a plot device for his novel ``Le Rayon Vert.'' Green-flash photos and simulations will be shown. This material is based upon work supported by the NSF under Award No. ATM-9714357.

  8. Photolysis of alpha-xylyl chlorides: an efficient deep-UV photoinitiating system for radical and cationic polymerization.

    Science.gov (United States)

    Ponce, Patricia; Catalani, Luiz Henrique

    2004-07-01

    Photoacid generators (PAG) are chemical systems where light absorption renders strong acid formation, typically with quantum yields greater than one. Many compounds bearing halogen atoms are reported to produce hydrogen halides upon photolysis. Here, alpha-chloroxylene derivatives (ortho, meta and para) were subject of a photolysis study in order to: (i) determine the operative mechanism, (ii) identify the products formed and (iii) quantify the amount of HCl formed. Product structure and quantum yields of HCl formation where determined for the photolysis of alpha-chloro-o-xylene (1), alpha-chloro-m-xylene (2), alpha-chloro-p-xylene (3), alpha, alpha'-dichloro-o-xylene (4), alpha, alpha'-dichloro-m-xylene (5) and alpha, alpha'-dichloro-p-xylene (6) in apolar (benzene, cumene, ethylbenzene, toluene and isooctane) and polar (methanol, n-propanol, isopropyl alcohol) solvents. Some of these compounds were analysed by laser flash photolysis in argon-purged isooctane as solvent to examine the possible reaction intermediates involved. The observed products are derived from typical radical reactions like recombination, dimerization and hydrogen abstraction from the starting compound or from solvents. The formation of HCl is expected as the result of C-Cl homolysis followed by hydrogen abstraction by chlorine atom. The results showed yields ranging from 1.2 to 18, depending on the conditions used. These numbers indicate the potential use of these compounds as PAG systems for the deep UV region.

  9. Floods and Flash Flooding

    Science.gov (United States)

    Floods and flash flooding Now is the time to determine your area’s flood risk. If you are not sure whether you ... If you are in a floodplain, consider buying flood insurance. Do not drive around barricades. If your ...

  10. Investigating ion channel distribution using a combination of spatially limited photolysis, Ca(2+) imaging, and patch clamp recording.

    Science.gov (United States)

    Almassy, Janos; Yule, David I

    2013-01-01

    The production of saliva by parotid acinar cells is stimulated by Ca(2+) activation of Cl(-) and K(+) channels located in the apical plasma membrane of these polarized cells. Here, we utilize a combination of spatially limited flash photolysis, Ca(2+) imaging, and electrophysiological recording to investigate the distinct distribution of Ca(2+)-dependent ion channels in the plasma membrane (PM) of enzymatically isolated murine parotid acinar cells. In these experiments, the aim of photolysis is to selectively target and modify the activity of ion channels, thereby revealing membrane-domain-specific differences in distribution. Specifically, the relative distribution of channels to either apical or basal PM can be investigated. Since there is substantial evidence that Ca(2+)-dependent Cl(-) channels are exclusively localized to the apical membrane of acinar cells, this provides an important electrophysiological verification that a particular membrane has been specifically targeted.

  11. Natural and human causes of a flash flood in a small catchment (Rhodes Island, Greece) based on atmospheric forcing and runoff modeling techniques

    Science.gov (United States)

    Karalis, Sotirios; Katsafados, Petros; Karymbalis, Efthimios; Tsanakas, Konstantinos; Valkanou, Kanella

    2014-05-01

    This study investigates the natural (hydro-meteorological and geomorphological) and human induced factors responsible for a flash flood event that occurred on November 22nd, 2013 in a small ungauged catchment (covering an area of about 24km2) of Rhodes Island, Greece. The flash flooding killed four people and caused over â¬10 million worth of damages located mainly around the Kremasti village. In this study the reconstruction of this extreme hydro-meteorological event is attempted by using detailed spatiotemporal rainfall information, a physically based hydrological model (LISEM) and the 1D hydraulic model HEC-RAS. Furthermore, the human impacts, which are responsible for extreme flood discharge within the drainage basin, are recorded and mapped. The major meteorological feature of this event is associated with the passage of a cold front over SE Aegean Sea. The destructive flash flood was triggered by the extreme precipitation (almost 100 mm in 4 hours was recorded at the meteorological stations closest to the flooded area). An advanced nowcasting method is applied in order to provide high spatiotemporal distribution of the precipitation over the catchment area. OpenLisem (Limbourg Soil Erosion Model) is used as a runoff model for exploring the response of the catchment. It is a freeware raster model (based on PCRaster) that simulates the surface water and sediment balance for every gridcell. It is event based and has fine spatial and temporal resolution. The model is designed to simulate the effects of detailed land use changes or conservation measures on runoff, flooding and erosion during heavy rainstorms. Since OpenLISEM provides a detailed simulation of runoff processes, it is very demanding on input data (it requires a minimum of 24 maps depending on the input options). The PCRaster GIS functionality was used to derive the necessary data from the basic maps (DEM, land unit map and map of impermeable areas). The sources for the basic maps include geological

  12. Professional Flash Lite Mobile Development

    CERN Document Server

    Anderson, J G

    2010-01-01

    Discover how to create Flash Lite mobile apps from the ground up. Adobe Flash is an ideal choice for developing rich interactive content for "Flash-enabled" mobile devices; and with this book, you'll learn how to create unique applications with Flash Lite. Through a series of code samples and extensive example applications, you'll explore the core concepts, key features, and best practices of the Flash Lite player. Coverage reveals various ways to develop Flash mobile content, create applications with a cross-platform programming framework based on the Model, View and Controller conc

  13. Thermal Diffusivity and Specific Heat Measurements of Titanium Potassium Perchlorate Titanium Subhydride Potassium Perchlorate 9013 Glass 7052 Glass SB-14 Glass and C-4000 Muscovite Mica Using the Flash Technique

    Energy Technology Data Exchange (ETDEWEB)

    Specht, Paul Elliott [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cooper, Marcia A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-02-01

    The flash technique was used to measure the thermal diffusivity and specific heat of titanium potassium perchlorate (TKP) ignition powder (33wt% Ti - 67wt% KP) with Ventron sup- plied titanium particles, TKP ignition powder (33wt% Ti - 67wt% KP) with ATK supplied titanium particles, TKP output powder (41wt% Ti - 59wt% KP), and titanium subhydride potassium perchlorate (THKP) (33wt% TiH 1.65 - 67wt% KP) at 25°C. The influence of density and temperature on the thermal diffusivity and specific heat of TKP with Ventron supplied titanium particles was also investigated. Lastly, the thermal diffusivity and specific heats of 9013 glass, 7052 glass, SB-14 glass, and C-4000 Muscovite mica are presented as a function of temperature up to 300° C.

  14. Thermal Diffusivity and Specific Heat Measurements of Titanium Potassium Perchlorate Titanium Subhydride Potassium Perchlorate 9013 Glass 7052 Glass SB-14 Glass and C-4000 Muscovite Mica Using the Flash Technique.

    Energy Technology Data Exchange (ETDEWEB)

    Specht, Paul Elliott; Cooper, Marcia A.

    2015-02-01

    The flash technique was used to measure the thermal diffusivity and specific heat of titanium potassium perchlorate (TKP) ignition powder (33wt% Ti - 67wt% KP) with Ventron sup- plied titanium particles, TKP ignition powder (33wt% Ti - 67wt% KP) with ATK supplied titanium particles, TKP output powder (41wt% Ti - 59wt% KP), and titanium subhydride potassium perchlorate (THKP) (33wt% TiH 1.65 - 67wt% KP) at 25 o C. The influence of density and temperature on the thermal diffusivity and specific heat of TKP with Ventron supplied titanium particles was also investigated. Lastly, the thermal diffusivity and specific heats of 9013 glass, 7052 glass, SB-14 glass, and C-4000 Muscovite mica are presented as a function of temperature up to 300 o C.

  15. Laser flash induced electron transfer in P450cam monooxygenase: putidaredoxin reductase-putidaredoxin interaction.

    Science.gov (United States)

    Sevrioukova, I F; Hazzard, J T; Tollin, G; Poulos, T L

    2001-09-04

    The P450cam monooxygenase from Pseudomonas putida consists of three redox proteins: NADH-putidaredoxin reductase (Pdr), putidaredoxin (Pdx), and cytochrome P450cam. The redox properties of the FAD-containing Pdr and the mechanism of Pdr-Pdx complex formation are the least studied aspects of this system. We have utilized laser flash photolysis techniques to produce the one-electron-reduced species of Pdr, to characterize its spectral and electron-transferring properties, and to investigate the mechanism of its interaction with Pdx. Upon flash-induced reduction by 5-deazariboflavin semiquinone, the flavoprotein forms a blue neutral FAD semiquinone (FADH(*)). The FAD semiquinone was unstable and partially disproportionated into fully oxidized and fully reduced flavin. The rate of FADH(*) decay was dependent on ionic strength and NAD(+). In the mixture of Pdr and Pdx, where the flavoprotein was present in excess, electron transfer (ET) from FADH(*) to the iron-sulfur cluster was observed. The Pdr-to-Pdx ET rates were maximal at an ionic strength of 0.35 where a kinetic dissociation constant (K(d)) for the transient Pdr-Pdx complex and a limiting k(obs) value were equal to 5 microM and 226 s(-1), respectively. This indicates that FADH(*) is a kinetically significant intermediate in the turnover of P450cam monooxygenase. Transient kinetics as a function of ionic strength suggest that, in contrast to the Pdx-P450cam redox couple where complex formation is predominantly electrostatic, the Pdx-Pdr association is driven by nonelectrostatic interactions.

  16. Foundation Flash Cartoon Animation

    CERN Document Server

    Jones, Tim; Rosson, Allan S

    2008-01-01

    One of Flash s most common uses is still animation for cartoons, games, advertising etc, and this book takes a fresh look at the topic, breaking it down pre-production, production, and post production, and looking at each section in detail, and covering topics such as storyboarding, character libraries and camera mechanics like no Flash book has before. The book is written by members of the Emmy award winning ANIMAX team, who have created work for clients such as Disney, AOL, Fox, WWE, ESPN, and Sesame workshop. This book is an opportunity for them to share their secrets, and is written to sui

  17. Learning Flash CS4 Professional

    CERN Document Server

    Shupe, Rich

    2009-01-01

    Learning Flash CS4 Professional offers beginners and intermediate Flash developers a unique introduction to the latest version of Adobe's powerful multimedia application. This easy-to-read book is loaded with full-color examples and hands-on tasks to help you master Flash CS4's new motion editor, integrated 3D system, and character control using the new inverse kinematics bones animation system. No previous Flash experience is necessary.

  18. Matrix-IR spectroscopic investigations of the thermolysis and photolysis of diazoamides.

    Science.gov (United States)

    Wentrup, Curt; Bibas, Hervé; Kuhn, Arvid; Mitschke, Ullrich; McMills, Mark C

    2013-11-01

    Matrix photolysis of N,N-dialkyldiazoacetamides 1a-d at 7-10 K results in either the formation of C-H insertion products (in case of N,N-dimethyl and N,N-diethyl diazoamides) or almost exclusive Wolff rearrangement to ketenes (in the case of the cyclic diazoamides N-(diazoacetyl)azetidine and N-(diazoacetyl)pyrrolidine). This can be ascribed to higher activation barriers for the approach of the singlet carbene p orbital in 5 (or of the diazo carbon in an excited state of 1) to the stronger and "tied back" nature of the C-H bonds in the cyclic substituents. In contrast, flash vacuum thermolysis (FVT) of diazoamides 1a-d, in which reactions of excited states are excluded, gives rise to clean C-H insertion with only minor Wolff rearrangement to ketenes.

  19. Flash Builder and Flash Catalyst The New Workflow

    CERN Document Server

    Peeters, Steven

    2010-01-01

    The Flash Platform is changing. Flash Builder and Flash Catalyst have brought a new separation of design and coding to web development that enables a much more efficient and streamlined workflow. For designers and developers used to the close confines of Flash, this is a hugely liberating but at first alien concept. This book teaches you the new workflow for the Flash platform. It gives an overview of the technologies involved and provides you with real-world project examples and best-practice guidelines to get from design to implementation with the tools at hand. * Includes many examples* Foc

  20. Jaan Toomik Flash Artis

    Index Scriptorium Estoniae

    1999-01-01

    1999. a. mai-juuni 'Flash Artis' on ajakirja Eesti korrespondendi Ando Keskküla artikkel Jaan Toomikust. Jaan Toomik on kutsutud esinema Londoni The Photographers' Gallery grupinäitusele, tema videot 'Father and Son' näidatakse Londonis avataval näitusel 'Near and Elsewhere' 11.-24. juunini

  1. Inessa Josing Flash Artis

    Index Scriptorium Estoniae

    1999-01-01

    'Flash Art'i' 1998. a. nov.-dets. numbris Rosa Martínezi artiklis suvisest Manifesta II näitusest Luxembourg'is on positiivselt mainitud ka Inessa Josingut. Illustratsiooniks toodud seitsmest fotost ühel on I. Josingu aknakujundus 'What Must I Do to be Saved?'

  2. Inessa Josing Flash Artis

    Index Scriptorium Estoniae

    1999-01-01

    'Flash Art'i' 1998. a. nov.-dets. numbris Rosa Martínezi artiklis suvisest Manifesta II näitusest Luxembourg'is on positiivselt mainitud ka Inessa Josingut. Illustratsiooniks toodud seitsmest fotost ühel on I. Josingu aknakujundus 'What Must I Do to be Saved?'

  3. Jaan Toomik Flash Artis

    Index Scriptorium Estoniae

    1999-01-01

    1999. a. mai-juuni 'Flash Artis' on ajakirja Eesti korrespondendi Ando Keskküla artikkel Jaan Toomikust. Jaan Toomik on kutsutud esinema Londoni The Photographers' Gallery grupinäitusele, tema videot 'Father and Son' näidatakse Londonis avataval näitusel 'Near and Elsewhere' 11.-24. juunini

  4. Selective formation of triplet alkyl nitrenes from photolysis of beta-azido-propiophenone and their reactivity.

    Science.gov (United States)

    Singh, Pradeep N D; Mandel, Sarah M; Sankaranarayanan, Jagadis; Muthukrishnan, Sivaramakrishnan; Chang, Mingxin; Robinson, Rachel M; Lahti, Paul M; Ault, Bruce S; Gudmundsdóttir, Anna D

    2007-12-26

    Photolysis of beta-azido propiophenone derivatives, 1, with built-in sensitizer units, leads to selective formation of triplet alkyl nitrenes 2 that were detected directly with laser flash photolysis (lambdamax = 325 nm, tau = 27 ms) and ESR spectroscopy (|D/hc| = 1.64 cm-1, |E/hc| = 0.004 cm-1). Nitrenes 2 were further characterized with argon matrix isolation, isotope labeling, and molecular modeling. The triplet alkyl nitrenes are persistent intermediates that do not abstract H-atoms from the solvent but do decay by dimerizing with another triplet nitrene to form azo products, rather than reacting with an azide precursor. The azo dimer tautomerizes and rearranges to form heterocyclic compound 3. Nitrene 2a, with an n,pi* configuration as the lowest triplet excited state of the its ketone sensitizer moiety, undergoes intramolecular 1,4-H-atom abstraction to form biradical 6, which was identified by argon matrix isolation, isotope labeling, and molecular modeling. beta-Azido-p-methoxy-propiophenone, with a pi,pi* lowest excited state of its triplet sensitizer moiety, does not undergo any secondary photoreactions but selectively yields only triplet alkyl nitrene intermediates that dimerize to form 3b.

  5. Photophysical properties of 5-hydroxyindole (5HI): Laser flash photolysis study

    Indian Academy of Sciences (India)

    T Misra; A K De; S K Pal; T Bhattacharya; T Ganguly

    2002-12-01

    Steady state fluorescence emission and transient absorption spectra of 9-fluorenone (9FL) were measured in the presence of 5-hydroxyindole (5HI) in highly polar acetonitrile (ACN) environment at ambient temperature. Cyclic voltammetry measurements demonstrate that ground state 5HI as a donor could take part in highly exothermic electron transfer (ET) reactions with excited 9FL, which should serve as electron acceptor. From the transient absorption measurements it is inferred that in geminate ion-pair (GIP) (or contact ion pair), formed initially due to photoinduced ET, the decay of this contact ion-pair occurs not only through ion recombination (back electron transfer to ground state of reactants), but through the other processes also such as proton-transfer (hydrogen abstraction) from radical cation to anion and separation of ion-pair producing the free ions. From the computed reorganisation energy parameter () and experimentally observed $- \\Delta G^{0}_{ET}$ values it is hinted that there is a possibility that highly exothermic forward electron transfer reactions in the singlet state 1 occur, within present reacting systems, in Marcus inverted region. Back transfer seems to follow the same path. Investigations with similar other reacting systems are underway.

  6. Mechanisms of Flash Sintering in Cubic Zirconia

    OpenAIRE

    Downs, John Axel

    2013-01-01

    The recently discovered flash sintering technique has shown that the application of a sufficiently large dc electric field (E-field) to a ceramic during sintering can cause sintering at temperatures several hundred degrees below conventional temperatures with sintering rates that allow for sintering in seconds rather than hours. This technique has already been demonstrated in wide range of ceramic materials including ionic conductors, electronic conductors, semi-conductors and insulators. Th...

  7. Hydrogen isotope fractionation in the photolysis of formaldehyde

    NARCIS (Netherlands)

    Rhee, T.S.; Brenninkmeijer, C.A.M.; Röckmann, T.

    2007-01-01

    Experiments investigating the isotopic fractionation in the formation of H2 by the photolysis of CH2O under tropospheric conditions are reported and discussed. The deuterium (D) depletion in H2 produced is 500(±20)‰ with respect to the parent CH2O. We also observed that complete photolysis of CH2O u

  8. Algorithms for Lunar Flash Video Search, Measurement, and Archiving

    Science.gov (United States)

    Swift, Wesley; Suggs, Robert; Cooke, Bill

    2007-01-01

    Lunar meteoroid impact flashes provide a method to estimate the flux of the large meteoroid flux and thus their hazard to spacecraft. Although meteoroid impacts on the Moon have been detected using video methods for over a decade, the difficulty of manually searching hours of video for the rare, extremely brief impact flashes has discouraged the technique's systematic implementation. A prototype has been developed for the purpose of automatically searching lunar video records for impact flashes, eliminating false detections, editing the returned possible flashes, Z and archiving and documenting the results. The theory and organization of the program is discussed with emphasis on the filtering out of several classes of false detections and retaining the brief portions of the raw video necessary for in depth analysis of the flashes detected. Several utilities for measurement, analysis, and location of the flashes on the moon included in the program are demonstrated. Application of the program to a year's worth of lunar observations is discussed along with examples of impact flashes as well as several classes of false impact flashes.

  9. The lightning flash

    CERN Document Server

    Cooray, Vernon

    2014-01-01

    With contributions from today's leading lightning engineers and researchers, this updated 2nd edition of Vernon Cooray's classic text, The Lightning Flash provides the reader with an essential introduction to lightning and its impact on electrical and electronic equipment. Providing the reader with a thorough background into almost every aspect of lightning and its impact on electrical and electronic equipment, this new edition is updated throughout and features eight new chapters that bring the science up to date.

  10. Flash Lidar Data Processing

    Science.gov (United States)

    Bergkoetter, M. D.; Ruppert, L.; Weimer, C. S.; Ramond, T.; Lefsky, M. A.; Burke, I. C.; Hu, Y.

    2009-12-01

    Late last year, a prototype Flash LIDAR instrument flew on a series of airborne tests to demonstrate its potential for improved vegetation measurements. The prototype is a precursor to the Electronically Steerable Flash LIDAR (ESFL) currently under development at Ball Aerospace and Technology Corp. with funding from the NASA Earth Science Technology Office. ESFL may soon significantly expand our ability to measure vegetation and forests and better understand the extent of their role in global climate change and the carbon cycle - all critical science questions relating to the upcoming NASA DESDynI and ESA BIOMASS missions. In order to more efficiently exploit data returned from the experimental Flash Lidar system and plan for data exploitation from future flights, Ball funded a graduate student project (through the Ball Summer Intern Program, summer 2009) to develop and implement algorithms for post-processing of the 3-Dimensional Flash Lidar data. This effort included developing autonomous algorithms to resample the data to a uniform rectangular grid, geolocation of the data, and visual display of large swaths of data. The resampling, geolocation, surface hit detection, and aggregation of frame data are implemented with new MATLAB code, and the efficient visual display is achieved with free commercial viewing software. These efforts directly support additional tests flights planned as early as October 2009, including possible flights over Niwot Ridge, CO, for which there is ICESat data, and a sea-level coastal area in California to test the effect of higher altitude (above ground level) on the divergence of the beams and the beam spot sizes.

  11. Physics Flash August 2016

    Energy Technology Data Exchange (ETDEWEB)

    Kippen, Karen Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-25

    Physics Flash is the newsletter for the Physics Division at Los Alamos National Laboratory. This newsletter is for August 2016. The following topics are covered: "Accomplishments in the Trident Laser Facility", "David Meyerhofer elected as chair-elect APS Nominating Committee", "HAWC searches for gamma rays from dark matter", "Proton Radiography Facility commissions electromagnetic magnifier", and "Cosmic ray muon computed tomography of spent nuclear fuel in dry storage casks."

  12. Four-dimensional multi-site photolysis of caged neurotransmitters

    Directory of Open Access Journals (Sweden)

    Mary Ann eGo

    2013-12-01

    Full Text Available Neurons receive thousands of synaptic inputs that are distributed in space and time. The systematic study of how neurons process these inputs requires a technique to stimulate multiple yet highly targeted points of interest along the neuron's dendritic tree. Three-dimensional multi-focal patterns produced via holographic projection combined with two-photon photolysis of caged compounds can provide for highly localized release of neurotransmitters within each diffraction-limited focus, and in this way emulate simultaneous synaptic inputs to the neuron. However, this technique so far cannot achieve time-dependent stimulation patterns due to fundamental limitations of the hologram-encoding device and other factors that affect the consistency of controlled synaptic stimulation. Here, we report an advanced technique that enables the design and application of arbitrary spatio-temporal photostimulation patterns that resemble physiological synaptic inputs. By combining holographic projection with a programmable high-speed light-switching array, we have overcome temporal limitations with holographic projection, allowing us to mimic distributed activation of synaptic inputs leading to action potential generation. Our experiments uniquely demonstrate multi-site two-photon glutamate uncaging in three dimensions with submillisecond temporal resolution. Implementing this approach opens up new prospects for studying neuronal synaptic integration in four dimensions.

  13. Radiometry of flashing LED sources

    Science.gov (United States)

    Gregory, Don A.; Medley, Stephanie; Roberts, Adam

    2008-08-01

    A laboratory based technique has been devised for measuring the illumination characteristics of flashing light emitting diode (LED) sources. The difference between the photopic measurement of a continuous source and a flashing source is that some analytic method must be incorporated into the measurement to account for the response of the eye. Ohno et al have devised an analytic expression for the impulse response of the eye, which closely matches existing forms used for finding effective intensity1. These other forms are the Blondel-Rey equation, the Form Factor method, and the Allard method.4,5,6 Ohno's research suggests a modified Allard method, but offers no procedure for actually making the measurement. In this research, the modified Allard1 method approach has been updated using standard laboratory equipment such as a silicon detector in conjunction with a digital multi-meter and Labview® software to make this measurement. Labview® allows exact computation of the modified Allard method. However, an approximation scheme for the conversion from radiometric units to photopic units must be adopted. The LED spectral form is approximately a Gaussian line shape with full width at half maximum of about 15 to 30nm. The Gaussian curve makes converting from radiometric to photopic units difficult. To simplify, the technique presented here estimates the spectral form of the LEDs to be a Dirac delta function situated at the peak wavelength. This allows the conversion from watts to lumens to be a simple application of the luminous efficiency curve.2 For LEDs with a full width half maximum of 20nm, this scheme is found to be accurate to +/- 5%.

  14. OH formation by HONO photolysis during the BERLIOZ experiment

    Science.gov (United States)

    Alicke, B.; Geyer, A.; Hofzumahaus, A.; Holland, F.; Konrad, S.; PäTz, H. W.; SchäFer, J.; Stutz, J.; Volz-Thomas, A.; Platt, U.

    2003-02-01

    The photolysis of nitrous acid (HONO) in the early morning hours is an important source of OH radicals, the most important daytime oxidizing species. Although the importance of this mechanism has been recognized for many years, no accurate quantification of this OH source is available, and the role of HONO photolysis is often underestimated. We present measurements of HONO and its precursor NO2 by Differential Optical Absorption Spectroscopy (DOAS) during the Berliner Ozonexperiment (BERLIOZ) field campaign in July/August 1998 at Pabstthum near Berlin, Germany. HONO concentrations, formation rates, and simultaneously measured HONO photolysis frequencies are used to calculate the total amount of OH formed by HONO photolysis during a full diurnal cycle. A comparison with the OH formation by photolysis of O3 and HCHO and by the reaction of alkenes with ozone shows that HONO photolysis contributed up to 20% of the total OH formed in a 24 hour period during this campaign. In the morning hours, HONO photolysis was by far the most important OH source during BERLIOZ.

  15. Using GHz Flash ADCs at STACEE

    Science.gov (United States)

    Zweerink, Jeffrey

    2002-04-01

    The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) detects 50-500 GeV gamma rays by sampling the Cherenkov light wavefront generated as the gamma rays interact with the atmosphere. Using steerable heliostat mirrors and stationary secondary optics at the National Solar Thermal Test Facility in New Mexico, the Cherenkov light is recorded using fast electronics with good timing. One significant improvement of the full 64 channel STACEE detector over earlier prototypes is the addition of GHz flash ADCs on each channel. We are developing analysis techniques to extract timing and other pulse information from the flash ADCs in order to 1.) discriminate against the abundant cosmic ray background, and 2.) understand how well the shower direction and energy can be reconstructed. We describe the techniques and present results from data taken during the 2001-2002 observing season.

  16. Temperature-dependent Kinetics on Laser Induced Photolysis of Aqueous CS2-HONO Solutions

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A laser photolysis/transient absorption technique has been employed to investigate the photolysis kinetics of aqueous CS2-HONO solutions at 355 nm. Spectral analysis shows that CS2OH will react with HONO to form CS2OH-HONO. Temperature dependent rate coefficients for the reaction are reported for the first time. The following Arrhenius expressions adequately summarize the kinetic data obtained over the temperature range 273-313 K (units are L.mol-1.s-1):ln k = (31.6 ± 0.6)-{(4.1 ± 0.2) ×103/T}, and the activation energy in unit of kJ.mol-1 is 32.47with the temperature accuracy 0.2 K.

  17. Direct observation of ClO from chlorine nitrate photolysis. [as mechanism of polar ozone depletion

    Science.gov (United States)

    Minton, Timothy K.; Nelson, Christine M.; Moore, Teresa A.; Okumura, Mitchio

    1992-01-01

    Chlorine nitrate photolysis has been investigated with the use of a molecular beam technique. Excitation at both 248 and 193 nanometers led to photodissociation by two pathways, ClONO2 yields ClO + NO2 and ClONO2 yields Cl + NO3, with comparable yields. This experiment provides a direct measurement of the ClO product channel and consequently raises the possibility of an analogous channel in ClO dimer photolysis. Photodissociation of the ClO dimer is a critical step in the catalytic cycle that is presumed to dominate polar stratospheric ozone destruction. A substantial yield of ClO would reduce the efficiency of this cycle.

  18. Modeling Flash Floods in Small Ungaged Watersheds using Embedded GIS

    OpenAIRE

    Knocke, Ethan William

    2006-01-01

    Effective prediction of localized flash flood regions for an approaching rainfall event requires an in-depth knowledge of the land surface and stream characteristics of the forecast area. Flash Flood Guidance (FFG) is currently formulated once or twice a day at the county level by River Forecast Centers (RFC) in the U.S. using modeling systems that contain coarse, generalized land and stream characteristics and hydrologic runoff techniques that often are not calibrated for the forecast regio...

  19. High-resolution infrared flash kinetic spectroscopy of OH radicals

    Energy Technology Data Exchange (ETDEWEB)

    Schiffman, A.; Nelson, D.D. Jr.; Robinson, M.S.; Nesbitt, D.J. (Univ. of Colorado, Boulder (United States) National Inst. of Standards and Tech., Boulder, CO (United States))

    1991-04-04

    A high-resolution infrared flash kinetic spectrometer is used for time- and frequency-resolved studies of the OH radical. OH is produced by 193-nm excimer laser photolysis of HNO{sub 3}/buffer gas mixtures in a 100-cm flow tube and is probed via weak fractional absorption of light from a widely tunable (2.35-3.59 {mu}m) single-mode ({Delta}{nu} {le} 2 MHz) color center laser. The IR absorption technique allows fast ({le}10{sup {minus}6} s), sensitive (<10{sup 9} radicals/cm{sup 3} per quantum state) detection of OH and is designed to permit determination of absolute OH number densities. The spectrometer is used to measure rate constants for the reactions of OH with ethane (k{sub 1}), propane (k{sub 2}), n-butane (k{sub 3}), and isobutane (k{sub 4}). The reliability of these measurements is tested on a variety of rotational, spin-orbit, and {lambda}-doublet states, with several buffer gases, and over more than an order of magnitude of alkane concentrations. The resulting rate constants are, in units of 10{sup {minus}12} cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}, k{sub 1} = 0.243 {plus minus} 0.012, k{sub 2} = 1.02 {plus minus} 0.05, k{sub 3} = 2.35 {plus minus} 0.08, and k{sub 4} = 2.11 {plus minus} 0.09. The rate constants for the ethane, n-butane, and isobutane reactions agree with some previous determinations but are found to be between 10% and 25% lower than values currently used in atmospheric modeling; it is recommended that these values be revised to reflect the lower rates from this study. Current models of atmospheric air flow based on these rate constants, as well as those previously accepted values, are found to be inconsistent with daily changes in observed atmospheric alkane concentrations.

  20. Flash Point Performance Evaluation

    Science.gov (United States)

    2014-03-01

    7094 Grabner D3828B Seta Flash CL12-3453 42.5 43.8 43.8 47.7 44.3 47.3 42.0 42.5 43.8 43.8 47.7 45.3 47.2 42.0 CL12-3475 58.5 61.7 58.7 59.7 61.3...division of Petroleum Analyzers Company (PAC) Houston, TX 14. Herzog is division of PAC 15. Stanhope- Seta , London, UK 16. Grabner Instruments is a

  1. Methods of flash sintering

    Energy Technology Data Exchange (ETDEWEB)

    Raj, Rishi; Cologna, Marco; Francis, John S.

    2016-05-10

    This disclosure provides methods of flash sintering and compositions created by these methods. Methods for sintering multilayered bodies are provided in which a sintered body is produced in less than one minute. In one aspect, each layer is of a different composition, and may be constituted wholly from a ceramic or from a combination of ceramic and metallic particles. When the body includes a layer of an anode composition, a layer of an electrolyte composition and a layer of a cathode composition, the sintered body can be used to produce a solid oxide fuel cell.

  2. Photochemical of Polychlorinated biphenyl by the photolysis and ...

    African Journals Online (AJOL)

    Michael Horsfall

    organic pollutants (POPs) that are of international concern because of global .... analysis. For quality control, the experiments were conducted in three replicates. ... Table 2: Effect of UV intensity on PCBs degradation efficiency (%) of photolysis.

  3. Photolysis of rac-leucine with circularly polarized synchrotron radiation.

    Science.gov (United States)

    Meierhenrich, Uwe J; Filippi, Jean-Jacques; Meinert, Cornelia; Hoffmann, Søren V; Bredehöft, Jan Hendrik; Nahon, Laurent

    2010-06-01

    Amino acids that pass the RNA machinery in living organisms occur in L-configuration. The question on the evolutionary origin of this biomolecular asymmetry remains unanswered to this day. Amino acids were detected in artificially produced interstellar ices, and L-enantiomer-enriched amino acids were identified in CM-type meteorites. This hints at a possible interstellar/circumstellar origin of the amino acids themselves as well as their stereochemical asymmetry. Based upon the current knowledge about the occurrence of circularly-polarized electromagnetic radiation in interstellar environments, we subjected rac-leucine to far-UV circularly-polarized synchrotron radiation. Asymmetric photolysis was followed by an analysis in an enantioselective GC/MS system. Here, we report on an advanced photolysis rate of more than 99% for leucine. The results indicate that high photolysis rates can occur under the chosen conditions, favoring enantioselective photolysis. In 2014, the obtained results will be reexamined by cometary mission Rosetta.

  4. Solvent Effect on the Photolysis of Riboflavin.

    Science.gov (United States)

    Ahmad, Iqbal; Anwar, Zubair; Ahmed, Sofia; Sheraz, Muhammad Ali; Bano, Raheela; Hafeez, Ambreen

    2015-10-01

    The kinetics of photolysis of riboflavin (RF) in water (pH 7.0) and in organic solvents (acetonitrile, methanol, ethanol, 1-propanol, 1-butanol, ethyl acetate) has been studied using a multicomponent spectrometric method for the assay of RF and its major photoproducts, formylmethylflavin and lumichrome. The apparent first-order rate constants (k obs) for the reaction range from 3.19 (ethyl acetate) to 4.61 × 10(-3) min(-1) (water). The values of k obs have been found to be a linear function of solvent dielectric constant implying the participation of a dipolar intermediate along the reaction pathway. The degradation of this intermediate is promoted by the polarity of the medium. This indicates a greater stabilization of the excited-triplet states of RF with an increase in solvent polarity to facilitate its reduction. The rate constants for the reaction show a linear relation with the solvent acceptor number indicating the degree of solute-solvent interaction in different solvents. It would depend on the electron-donating capacity of RF molecule in organic solvents. The values of k obs are inversely proportional to the viscosity of the medium as a result of diffusion-controlled processes.

  5. Direct photolysis of polycyclic aromatic hydrocarbons in drinking water sources

    Energy Technology Data Exchange (ETDEWEB)

    Sanches, S. [Instituto de Biologia Experimental e Tecnologica (IBET), Av. Republica, Qta. do Marques (EAN), 2784-505 Oeiras (Portugal); Instituto de Tecnologia Quimica e Biologica (ITQB) - Universidade Nova de Lisboa (UNL), Av. da Republica, Estacao Agronomica Nacional, 2780-157 Oeiras (Portugal); Leitao, C. [Instituto de Tecnologia Quimica e Biologica (ITQB) - Universidade Nova de Lisboa (UNL), Av. da Republica, Estacao Agronomica Nacional, 2780-157 Oeiras (Portugal); Penetra, A.; Cardoso, V.V.; Ferreira, E.; Benoliel, M.J. [Empresa Portuguesa das Aguas Livres, S.A., Avenida de Berlim, 15, 1800-031 Lisboa (Portugal); Crespo, M.T. Barreto [Instituto de Biologia Experimental e Tecnologica (IBET), Av. Republica, Qta. do Marques (EAN), 2784-505 Oeiras (Portugal); Instituto de Tecnologia Quimica e Biologica (ITQB) - Universidade Nova de Lisboa (UNL), Av. da Republica, Estacao Agronomica Nacional, 2780-157 Oeiras (Portugal); Pereira, V.J., E-mail: vanessap@itqb.unl.pt [Instituto de Biologia Experimental e Tecnologica (IBET), Av. Republica, Qta. do Marques (EAN), 2784-505 Oeiras (Portugal); Instituto de Tecnologia Quimica e Biologica (ITQB) - Universidade Nova de Lisboa (UNL), Av. da Republica, Estacao Agronomica Nacional, 2780-157 Oeiras (Portugal)

    2011-09-15

    Highlights: {yields} Low pressure UV photolysis can be used by drinking water utilities to degrade PAHs. {yields} Real water matrices with different compositions were tested. {yields} Photolysis kinetic parameters and by-product formation are described. {yields} The formation of photolysis by-products is highly dependent on the source waters. - Abstract: The widely used low pressure lamps were tested in terms of their efficiency to degrade polycyclic aromatic hydrocarbons listed as priority pollutants by the European Water Framework Directive and the U.S. Environmental Protection Agency, in water matrices with very different compositions (laboratory grade water, groundwater, and surface water). Using a UV fluence of 1500 mJ/cm{sup 2}, anthracene and benzo(a)pyrene were efficiently degraded, with much higher percent removals obtained when present in groundwater (83-93%) compared to surface water (36-48%). The removal percentages obtained for fluoranthene were lower and ranged from 13 to 54% in the different water matrices tested. Several parameters that influence the direct photolysis of polycyclic aromatic hydrocarbons were determined and their photolysis by-products were identified by mass spectrometry. The formation of photolysis by-products was found to be highly dependent on the source waters tested.

  6. Geomorphological factors of flash floods

    Science.gov (United States)

    Kuznetsova, Yulia

    2016-04-01

    Growing anthropogenic load, rise of extreme meteorological events frequency and total precipitation depth often lead to increasing danger of catastrophic fluvial processes worldwide. Flash floods are one of the most dangerous and less understood types of them. Difficulties of their study are mainly related to short duration of single events, remoteness and hard access to origin areas. Most detailed researches of flash floods focus on hydrological parameters of the flow itself and its meteorological factors. At the same time, importance of the basin geological and geomorphological structure for flash floods generation and the role they play in global sediment redistribution is yet poorly understood. However, understanding and quantitative assessment of these features is a real basis for a complete concept of factors, characteristics and dynamics of flash floods. This work is a review of published data on flash floods, and focuses on the geomorphological factors of the phenomenon. We consider both individual roles and interactions between different geomorphological features (the whole basin parameters, characteristics of the single slopes and valley bottom). Special attention is paid to critical values of certain factors. This approach also highlights the gaps or less studied factors of flash floods. Finally, all data is organized into a complex diagram that may be used for flash floods modeling. This also may help to reach a new level of flash flood predictions and risk assessment.

  7. Flashing LEDs for Microalgal Production.

    Science.gov (United States)

    Schulze, Peter S C; Guerra, Rui; Pereira, Hugo; Schüler, Lisa M; Varela, João C S

    2017-08-30

    Flashing lights are next-generation tools to mitigate light attenuation and increase the photosynthetic efficiency of microalgal cultivation systems illuminated by light-emitting diodes (LEDs). Optimal flashing light conditions depend on the reaction kinetics and properties of the linear electron transfer chain, energy dissipation, and storage mechanisms of a phototroph. In particular, extremely short and intense light flashes potentially mitigate light attenuation in photobioreactors without impairing photosynthesis. Intelligently controlling flashing light units and selecting electronic components can maximize light emission and energy efficiency. We discuss the biological, physical, and technical properties of flashing lights for algal production. We combine recent findings about photosynthetic pathways, self-shading in photobioreactors, and developments in solid-state technology towards the biotechnological application of LEDs to microalgal production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Distributed query processing in flash-based sensor networks

    Institute of Scientific and Technical Information of China (English)

    Jianliang XU; Xueyan TANG; Wang-Chien LEE

    2008-01-01

    Wireless sensor networks are used in a large array of applications to capture,collect,and analyze physical environmental data.Many existing sensor systems instruct sensor nodes to report their measurements to central repositories outside the network,which is expensive in energy cost.Recent technological advances in flash memory have given rise to the development of storagecentric sensor networks,where sensor nodes are equipped with high-capacity flash memory storage such that sensor data can b.e stored and managed inside the network to reduce expensive communication.This novel architecture calls for new data management techniques to fully exploit distributed in-network data storage.This paper describes some of our research on distributed query processing in such flash-based sensor networks.Of particular interests are the issues that arise in the design of storage management and indexing structures combining sensor system workload and read/write/erase characteristics of flash memory.

  9. Step & flash imprint lithography

    Directory of Open Access Journals (Sweden)

    Douglas J. Resnick

    2005-02-01

    Full Text Available The escalating cost of next generation lithography (NGL is driven in part by the need for complex sources and optics. The cost for a single NGL tool could soon exceed $50 million, a prohibitive amount for many companies. As a result, several research groups are looking at alternative, low-cost methods for printing sub-100 nm features. Many of these methods are limited in their ability to do precise overlay. In 1999, Willson and Sreenivasan developed step and flash imprint lithography (S-FIL™. The use of a quartz template opens up the potential for optical alignment of the wafer and template. This paper reviews several key aspects of the S-FIL process, including template, tool, ultraviolet (UV-curable monomer, and pattern transfer. Two applications are also presented: contact holes and surface acoustic wave (SAW filters.

  10. Photolysis of aromatic pollutants in clean and dirty ice

    Science.gov (United States)

    Kahan, T.; Malley, P.; Stathis, A.

    2015-12-01

    Anthropogenic aromatic pollutants such as polycyclic aromatic hydrocarbons (PAHs) and substituted benzenes often become more toxic following atmospheric oxidation. Photolysis of these pollutants in ice can be much faster than that in aqueous solution, which might lead to higher carcinogenic loadings in snow-covered regions. In this work we investigate two things. First, we investigate whether toluene, which has been detected at very elevated concentrations near hydraulic fracturing operations, can undergo photolysis at ice surfaces. Toluene in aqueous solution does not absorb sunlight, so photolysis has not been considered a potential atmospheric fate. However, benzene was recently demonstrated to undergo a significant red shift in its absorbance at ice surfaces, leading to photolysis under environmentally-relevant conditions. Here we show that toluene also undergoes photolysis at ice surfaces. In a second set of experiments, we have investigated the effects of organic matter on the photolysis kinetics ofPAHs in ice and at ice surfaces. We found that very small loadings of hydrophobic organics such as octanol can significantly suppress PAH photolysis kinetics in ice, but that the primary effect of the more soluble fulvic acid is competitive photon absorption. Our results show that photochemistry of anthropogenic pollutants can follow very different mechanisms and kinetics in ice than in aqueous solution, and that the photochemical fate of these pollutants depends strongly on the composition of the snow. These results have implications for pollutant fate and human health in a wide range of snow-covered environments including remote areas, cities, and regions near gas and oil extraction operations.

  11. Techniques of the FLASH Thin Target Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Abbasi, R.; Abu-Zayyad, T.; Belov, K.; Belz, J.; /Utah U.; Bergman, D.R.; /Rutgers U., Piscataway; Cao, Z.; /Utah U.; Chang, F.-Y.; Chen, C.-C.; Chen, C.-W.; /Taiwan, Natl. Taiwan U.; Chen, P.; /SLAC; Dalton, M.; Fedorova, Y.; /Utah U.; Field, C.; Hast, C.; /SLAC; Huang, M.A.; /Taiwan, Natl. Taiwan U.; Huntemeyer, P.; /Utah U.; Hwang, W.-Y.P.; /Taiwan, Natl. Taiwan U.; Iverson, R.; /SLAC; Jones, B.F.; Jui, C.C.H.; /Utah U.; Lin, G.-L.; /Taiwan, Natl. Taiwan U. /Utah U. /SLAC /Utah U. /Rutgers U., Piscataway /SLAC /Rutgers U., Piscataway

    2007-10-30

    The fluorescence yield in air is reported for wavelength and pressure ranges of interest to ultra-high energy cosmic ray detectors. A 28.5 GeV electron beam was used to excite the fluorescence. Central to the approach was the system calibration, using Rayleigh scattering of a nitrogen laser beam. In atmospheric pressure dry air, at 304 K the yield is 20.8 {+-} 1.6 photons per MeV.

  12. Application of the UAV aerial technique in evaluation of flash flood disasters%无人机航测技术在山洪灾害调查评价中的应用

    Institute of Scientific and Technical Information of China (English)

    刘昌军; 郭良; 岳冲

    2014-01-01

    利用无人机航测技术获取影像分辨率高、机动灵活、不受天气和复杂地形影响的技术特点,提出将无人机低空航测技术应用于获取复杂山丘区小流域基础地理信息资料。以陕西商洛某小流域调查评价应用为例,系统地介绍了应用无人机航测技术获取调查评价所需的高清晰航片、高精度DEM、河道断面、居民沿高程展布以及地表植被和土地利用分类信息的流程与方法,提出了各个环节关键技术的解决方案,编制了基于无人机航测技术的数据处理软件。应用案例表明,该方法可以快速获取山丘区小流域内的高清晰航片,数据处理速度快,精度高,能够满足山洪灾害调查评价工作要求,获取的数据可大大提高洪水预报的精度。该技术在即将开展的全国山洪灾害调查评价工作中将发挥巨大作用,具有较大的应用前景。%Taking advantage of the UAV aerial technology’s characteristics of high resolution images, flexibility, and suitable for wide weather and topographic conditions , low-altitude UAV aerial system is built for obtaining basic geographic information data in smal watersheds of complicate hil y terrain. Taking a smal watershed in Shangluo of Shanxi province as an example, the procedures and methods of using UVA aerial techniques are systematical y introduced to obtain high-resolution aerial photos, high-precision DEM, river cross-sections, residential housing distribution along hil sides, as wel as the ground vegetation and land use classification. The solutions of the key technology issues in al aspects are proposed, data processing software is developed based on UAV aerial technology. The case study show that the system can be used to quickly obtain high-resolution aerial photographs in smal watershed of hil y region to meet the data requirements of rapid processing and high precision for investigation and evaluation of flash flood

  13. Flash floods in the Tatra Mountain streams: frequency and triggers.

    Science.gov (United States)

    Ballesteros-Cánovas, J A; Czajka, B; Janecka, K; Lempa, M; Kaczka, R J; Stoffel, M

    2015-04-01

    Flash floods represent a frequently recurring natural phenomenon in the Tatra Mountains. On the northern slopes of the mountain chain, located in Poland, ongoing and expected future changes in climate are thought to further increase the adverse impacts of flash floods. Despite the repeat occurrence of major floods in the densely populated foothills of the Polish Tatras, the headwaters have been characterized by a surprising lack of data, such that any analysis of process variability or hydrometeorological triggers has been largely hampered so far. In this study, dendrogeomorphic techniques have been employed in four poorly-gauged torrential streams of the northern slope of the Tatra Mountains to reconstruct temporal and spatial patterns of past events. Using more than 1100 increment cores of trees injured by past flash floods, we reconstruct 47 events covering the last 148 years and discuss synoptic situations leading to the triggering of flash floods with the existing meteorological and flow gauge data. Tree-ring analyses have allowed highlighting the seasonality of events, providing new insights about potential hydrometeorological triggers as well as a differentiating flash flood activity between catchments. Results of this study could be useful to design future strategies to deal with flash flood risks at the foothills of the Polish Tatras and in the Vistula River catchment.

  14. Flash light sintering of nickel nanoparticles for printed electronics

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung-Hyeon [School of Mechanical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kim, Hak-Sung, E-mail: kima@hanyang.ac.kr [School of Mechanical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Institute of Nano Science and Technology, Hanyang University, Seoul 133-79 (Korea, Republic of)

    2014-01-01

    In this paper, a sintering process for nickel nanoparticles using flash light irradiation was investigated for multilayer ceramic capacitors, magnetic devices and printed electronics. The existence of a small amount of 10 nm size nanoparticles in the ink significantly improved the flash light absorption and induced the melting and sintering of the nanoparticles. Due to this phenomenon, uniform diameter nickel nanoparticles (50 nm) could not be sintered, while the nickel nanoparticles with varying diameters (5–500 nm) were sintered by flash light irradiation. In order to acquire high electrical conductivity in the sintered nickel nanoparticles, several flash light sintering parameters such as light energy and pulsed light patterns were optimized. Also, the nickel nano-ink was optimized by changing the weight fractions of organic binder in the ink. - Highlights: • Nickel nanoparticle was sintered by flash light irradiation technique. • The existence of 10 nm size nanoparticles improved the flash light absorption. • The melting temperature of the 10 nm size nanoparticles is significantly decreased. • The only nickel nanoparticles with varying diameters (5–500 nm) were sintered. • Several sintering parameters were optimized for conductivity of nickel nanoparticle.

  15. Flash sintering of ceramic materials

    OpenAIRE

    Dancer, C. E. J.

    2016-01-01

    During flash sintering, ceramic materials can sinter to high density in a matter of seconds while subjected to electric field and elevated temperature. This process, which occurs at lower furnace temperatures and in shorter times than both conventional ceramic sintering and field-assisted methods such as spark plasma sintering, has the potential to radically reduce the power consumption required for the densification of ceramic materials. This paper reviews the experimental work on flash sint...

  16. Laboratory study of nitrate photolysis in Antarctic snow

    DEFF Research Database (Denmark)

    Berhanu, Tesfaye A.; Meusinger, Carl; Erbland, Joseph;

    2014-01-01

    Atmospheric nitrate is preserved in Antarctic snow firn and ice. However, at low snow accumulation sites, post-depositional processes induced by sunlight obscure its interpretation. The goal of these studies (see also Paper I by Meusinger et al. [" Laboratory study of nitrate photolysis...... in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry," J. Chem. Phys. 140, 244305 (2014)]) is to characterize nitrate photochemistry and improve the interpretation of the nitrate ice core record. Naturally occurring stable isotopes in nitrate (15N, 17O, and 18O) provide...... additional information concerning post-depositional processes. Here, we present results from studies of the wavelength-dependent isotope effects from photolysis of nitrate in a matrix of natural snow. Snow from Dome C, Antarctica was irradiated in selected wavelength regions using a Xe UV lamp and filters...

  17. Chemically Patterned Inverse Opal Created by a Selective Photolysis Modification Process.

    Science.gov (United States)

    Tian, Tian; Gao, Ning; Gu, Chen; Li, Jian; Wang, Hui; Lan, Yue; Yin, Xianpeng; Li, Guangtao

    2015-09-01

    Anisotropic photonic crystal materials have long been pursued for their broad applications. A novel method for creating chemically patterned inverse opals is proposed here. The patterning technique is based on selective photolysis of a photolabile polymer together with postmodification on released amine groups. The patterning method allows regioselective modification within an inverse opal structure, taking advantage of selective chemical reaction. Moreover, combined with the unique signal self-reporting feature of the photonic crystal, the fabricated structure is capable of various applications, including gradient photonic bandgap and dynamic chemical patterns. The proposed method provides the ability to extend the structural and chemical complexity of the photonic crystal, as well as its potential applications.

  18. Effect of clouds on photolysis and oxidants in the troposphere

    Science.gov (United States)

    Tie, Xuexi; Madronich, Sasha; Walters, Stacy; Zhang, Renyi; Rasch, Phil; Collins, William

    2003-10-01

    Cloud layers in the troposphere influence photolysis rates (J values) and hence concentrations of chemical species. In order to study the impact of clouds on photolysis rates and oxidants, we have developed a simplified version of the National Center for Atmospheric Research (NCAR) Tropospheric Ultraviolet-Visible (TUV) model and have coupled the simplified TUV (otherwise known as the fast TUV (FTUV)) into the NCAR/Atmospheric Chemistry Division global transport chemical model (Model for Ozone and Related Chemical Tracers (MOZART-2)). The FTUV model has the same physical processes as the TUV model, except that the wavelength bins between 121 and 750 nm are reduced from 140 to 17. As a result, FTUV is about 8 times faster than the original TUV. Differences in the calculated photolysis rates between TUV and FTUV are generally less than 5% in the troposphere. Subgrid vertical distributions of clouds are also considered in the calculation of photolysis rates in MOZART-2. The method used in this study is a mixed maximum and random overlap scheme. The subgrid method increases the computation time for photolysis rates by a factor of 3 compared to a simple method in which clouds are uniformly distributed over the MOZART-2 grids. Our calculation shows that the uniform cloud distribution method tends to significantly overestimate back scattering on the top of clouds and overestimates the impact on photochemistry in the troposphere. The results suggest that clouds have important impacts on tropospheric chemistry. Global mean OH concentration increases by about 20% due to the impact of clouds. As a result, the calculated CH4 lifetime changes to 11 years for clear sky and 9 years for cloudy sky. The latter value is closer to the methane lifetime estimated from previous studies. Calculated CO surface concentrations are compared with observed values, showing an improvement when the impact of clouds on the photolysis rates is taken into account. Clouds also have important impacts

  19. Direct photolysis of nitroaromatic compounds in aqueous solutions

    Institute of Scientific and Technical Information of China (English)

    CHEN Bing; YANG Chun; GOH Ngoh Khang

    2005-01-01

    The direct photolysis of nitrobenzene and nitrophenols in aqueous solutions irradiated by polychromatic light were investigated.Several aromatic intermediates were identified as three nitrophenol isomers, nitrohydroquinone, nitrosobenzene, nitrocatechol, catechol and phenol. Nitrite and nitrate ions were also detected in the irradiated solution indicating direct photolysis of nitrobenzene or nitrophenols.The degradation of nitrobenzene and nitrophenols and the formation of three nitrophenol isomers were observed to follow zero-order kinetics. The quantum yields for nitrobenzene and nitrophenols removal are about 10-3 and 10-3-10-4 respectively. The mechanism for nitrobenzene degradation was suggested to follow mainly nitro-nitrite intramolecular arrangement.

  20. Laser photolysis of ionic liquid [bmim][PF6

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Photoinduced chemical reactions of 1-butyl-3-methylimidazolium hexafiuorophosphate ([bmim][PF6])were studied by laser photolysis at a wavelength of 266 nm. Excited triplet state 3[bmim]+* was observed, radical cation [bmim] 2+* and neutral [bmim]* radical via photoionization were also formed. Energy transfer from 3[bmim]+* to β-carotene was confirmed. Oxidation via one electron transfer from TMPD to 3[bmim]+* was also observed and the rate constant was determined to be 1.2 × 105 L. mol-1-s-1. The reaction of [bmim][PF6] with hydrated electron (eaq)was confirmed by laser photolysis in aqueous solution.

  1. Animating an Equation: A Guide to Using FLASH in Mathematics Education

    Science.gov (United States)

    Bakhoum, Ezzat G.

    2008-01-01

    Macromedia's FLASH development system can be a great tool for mathematics education. This article presents detailed Flash tutorials that were developed and taught by the author to a group of mathematics professors in a summer course in 2005. The objective was to educate the teachers in the techniques of animating equations and mathematical…

  2. Flash ADC data processing with correlation coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Blyth, D.; Gibson, M.; Mcfarland, D.; Comfort, J.R., E-mail: Joseph.Comfort@asu.edu

    2014-02-21

    The large growth of flash ADC techniques for processing signals, especially in applications of streaming data, raises issues such as data flow through an acquisition system, long-term storage, and greater complexity in data analysis. In addition, experiments that push the limits of sensitivity need to distinguish legitimate signals from noise. The use of correlation coefficients is examined to address these issues. They are found to be quite successful well into the noise region. The methods can also be extended to Field Programmable Gate Array modules for compressing the data flow and greatly enhancing the event rate capabilities.

  3. Photolysis of benzophenone with two-step two-laser excitation

    Institute of Scientific and Technical Information of China (English)

    CAI; Xichen

    2001-01-01

    [1]Carmichael, I., Hug, G. L., Triplet-triplet absorption spectra of organic molecules in condensed phases, J. Phys. Chem. Ref. Data, 1986, 15(1): 1-20.[2]Nikogosyan, D. N., Two-quantum UV photochemistry of nucleic acids: comparison with conventional low-intensity UV photochemistry and radiation chemistry, Int. J. Radiat. Biol., 1990, 57(2): 233-299.[3]Yao, S. D., Sheng, S. G., Cai, J. H. et al., Nanosecond pulse radiolysis studies in China, Radiat. Phys. Chem., 1995, 46:105-109.[4]Baumann, H.. Merckel, C., Timpe, H. -J., The laser versus the lamp: reactivity of the diphenyl ketyl radical in the ground and excited states. Chem. Phys. Lett., 1984, 103(6): 497-502.[5]Barral-Tosh, S., Chattopadhyay, S. K., Das, P. K., A laser flash photolysis study of paraquat reduction by photogenerated aromatic ketyl radicals and carbonyl triplets, J. Phys. Chem., 1984, 88: 1404-1408.[6]Elisei. F., Favaro, G., Ion-forming processes on 248 nm laser excitation of benzophenone in aqueous solution: a time-resolved absorption and conductivity study, J. Photochem. Photobiol. A: Chem., 1991, 59:243-253.

  4. Hydrogen peroxide evolution during V-UV photolysis of water.

    Science.gov (United States)

    Azrague, Kamal; Bonnefille, Eric; Pradines, Vincent; Pimienta, Véronique; Oliveros, Esther; Maurette, Marie-Thérèse; Benoit-Marquié, Florence

    2005-05-01

    Hydrogen peroxide evolution during the vacuum-ultraviolet (V-UV, 172 nm) photolysis of water is considerably affected by the presence of oxalic acid (employed as a model water pollutant) and striking differences are observed in the absence and in the presence of dioxygen.

  5. Postantibiotic effect of disinfection treatment by photolysis of hydrogen peroxide.

    Science.gov (United States)

    Odashima, Yu; Nakamura, Keisuke; Ikai, Hiroyo; Kanno, Taro; Meirelles, Luiz; Sasaki, Keiichi; Niwano, Yoshimi

    2014-04-01

    The purpose of the present study was to evaluate the postantibiotic effect (PAE) of the disinfection treatment by photolysis of H2O2. Postantibiotic effect was induced in Staphylococcus aureus and Streptococcus salivarius by exposing the bacteria to H2O2 at concentrations of 250-1000 mmol/l, laser irradiation at a wavelength of 405 nm, and the combination of both (photolysis of H2O2) for 10-30 seconds. The photolysis of H2O2 induced significantly longer PAE than other treatments. The PAE was augmented dependently on not only the concentration of H2O2 but the laser irradiation time. Electron spin resonance analysis showed that the hydroxyl radical was also generated dependently on both the concentration of H2O2 and the laser irradiation time, suggesting that the hydroxyl radicals contribute to the PAE. These results suggest that the disinfection treatment by photolysis of H2O2 induces PAE in S. aureus and S. salivarius even though they were treated for only 10-30 seconds.

  6. Document Flash Thermography

    OpenAIRE

    Larsen, Cory A.

    2011-01-01

    This thesis presents the application of ash thermography techniques to the analysis of documents. The motivation for this research is to develop the ability to non-destructively reveal covered writings in archaeological artifacts such as the Codex Selden or Egyptian car- tonnage. Current common signal processing techniques are evaluated for their effectiveness in enhancing subsurface writings found within a set of test documents. These processing techniques include: false colorization, contra...

  7. Flash Professional CS5 Digital Classroom

    CERN Document Server

    Gerantabee, Fred

    2011-01-01

    Learn Flash in a flash with this full-color book and video training package! Adobe Flash is used by designers, game programmers, and hobbyists to create interactive Web sites, digital experiences, and mobile content. The latest release of Flash promises exciting new capabilities and this book-and-video training package makes learning the new features of Flash less intimidating. Fifteen self-paced lessons encourage you to discover essential skills and explore new aspects of Flash. The tutorials featured in the videos are each approximately five minutes long and supplement the concepts and topic

  8. Flashing light in microalgae biotechnology.

    Science.gov (United States)

    Abu-Ghosh, Said; Fixler, Dror; Dubinsky, Zvy; Iluz, David

    2016-03-01

    Flashing light can enhance photosynthesis and improve the quality and quantity of microalgal biomass, as it can increase the products of interest by magnitudes. Therefore, the integration of flashing light effect into microalgal cultivation systems should be considered. However, microalgae require a balanced mix of the light/dark cycle for higher growth rates, and respond to light intensity differently according to the pigments acquired or lost during the growth. This review highlights recently published results on flashing light effect on microalgae and its applications in biotechnology, as well as the recently developed bioreactors designed to fulfill this effect. It also discusses how this knowledge can be applied in selecting the optimal light frequencies and intensities with specific technical properties for increasing biomass production and/or the yield of the chemicals of interest by microalgae belonging to different genera.

  9. Flash on disk for low-power multimedia computing

    Science.gov (United States)

    Singleton, Leo; Nathuji, Ripal; Schwan, Karsten

    2007-01-01

    Mobile multimedia computers require large amounts of data storage, yet must consume low power in order to prolong battery life. Solid-state storage offers low power consumption, but its capacity is an order of magnitude smaller than the hard disks needed for high-resolution photos and digital video. In order to create a device with the space of a hard drive, yet the low power consumption of solid-state storage, hardware manufacturers have proposed using flash memory as a write buffer on mobile systems. This paper evaluates the power savings of such an approach and also considers other possible flash allocation algorithms, using both hardware- and software-level flash management. Its contributions also include a set of typical multimedia-rich workloads for mobile systems and power models based upon current disk and flash technology. Based on these workloads, we demonstrate an average power savings of 267 mW (53% of disk power) using hardware-only approaches. Next, we propose another algorithm, termed Energy-efficient Virtual Storage using Application-Level Framing (EVS-ALF), which uses both hardware and software for power management. By collecting information from the applications and using this metadata to perform intelligent flash allocation and prefetching, EVS-ALF achieves an average power savings of 307 mW (61%), another 8% improvement over hardware-only techniques.

  10. Flash Builder building user interaction

    CERN Document Server

    Rocchi, Cesare

    2010-01-01

    Develop a working understanding of events and components, and containers and states so you can build and deploy RIAs in Flex. Work through a demo implementation of a login panel that employs feedback from the server side, to hone your understanding. Use the validators and the debugger to inspect your code execution. Building User Interaction is the second of five articles that will be compiled in the book, Data Visualization with Flash Builder: Designing RIA and AIR Applications with Remote Data Sources. Each full-color article illustrates specific aspects of Flash Builder data visualization

  11. Quick Guide to Flash Catalyst

    CERN Document Server

    Elmansy, Rafiq

    2011-01-01

    How do you transform user interface designs created in Photoshop or Illustrator into interactive web pages? It's easier than you think. This guide shows you how to use Adobe Flash Catalyst to create interactive UIs and website wireframes for Rich Internet Applications-without writing a single line of code. Ideal for web designers, this book introduces Flash Catalyst basics with detailed step-by-step instructions and screenshots that illustrate every part of the process. You'll learn hands-on how to turn your static design or artwork into working user interfaces that can be implemented in Fla

  12. Flash Builder charting and multimedia

    CERN Document Server

    Rocchi, Cesare

    2010-01-01

    Charting and multimedia are two vital tools for data-driven applications. Learn about the main components of the chart library included in Flash Builder, and see how to build and customize widely used charts. Turning your attention to the multimedia capabilities of the Flex framework, you will review the multimedia components built into the Flex library, and learn how to use ActionScript to manipulate video and audio files. Charting and Multimedia is the third of five articles that will be compiled in the book, Data Visualization with Flash Builder: Designing RIA and AIR Applications with Rem

  13. 3D Flash LIDAR Space Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Scientific Concepts, Inc. (ASC) is a small business that has developed 3D Flash LIDAR systems for space and terrestrial applications. 3D Flash LIDAR is...

  14. Differentiation of debris-flow and flash-flood deposits: implications for paleoflood investigations

    Science.gov (United States)

    Waythomas, Christopher F.; Jarrett, Robert D.; ,

    1993-01-01

    Debris flows and flash floods are common geomorphic processes in the Colorado Rocky Mountain Front Range and foothills. Usually, debris flows and flash floods are associated with excess summer rainfall or snowmelt, in areas were unconsolidated surficial deposits are relatively thick and slopes are steep. In the Front Range and foothills, flash flooding is limited to areas below about 2300m whereas, debris flow activity is common throughout the foothill and alpine zones and is not necessarily elevation limited. Because flash floods and debris flows transport large quantities of bouldery sediment, the resulting deposits appear somewhat similar even though such deposits were produced by different processes. Discharge estimates based on debris-flow deposits interpreted as flash-flood deposits have large errors because techniques for discharge retrodiction were developed for water floods with negligible sediment concentrations. Criteria for differentiating between debris-flow and flash-flood deposits are most useful for deposits that are fresh and well-exposed. However, with the passage of time, both debris-flow and flash-flood deposits become modified by the combined effects of weathering, colluviation, changes in surface morphology, and in some instances removal of interstitial sediment. As a result, some of the physical characteristics of the deposits become more alike. Criteria especially applicable to older deposits are needed. We differentiate flash-flood from debris-flow and other deposits using clast fabric measurements and other morphologic and sedimentologic techniques (e.g., deposit morphology, clast lithology, particle size and shape, geomorphic setting).

  15. Flash (Ultra-Rapid) Spark-Plasma Sintering of Silicon Carbide

    Science.gov (United States)

    Olevsky, Eugene A.; Rolfing, Stephen M.; Maximenko, Andrey L.

    2016-09-01

    A new ultra-rapid process of flash spark plasma sintering is developed. The idea of flash spark plasma sintering (or flash hot pressing - FHP) stems from the conducted theoretical analysis of the role of thermal runaway phenomena for material processing by flash sintering. The major purpose of the present study is to theoretically analyze the thermal runaway nature of flash sintering and to experimentally address the challenge of uncontrollable thermal conditions by the stabilization of the flash sintering process through the application of the external pressure. The effectiveness of the developed FHP technique is demonstrated by the few seconds-long consolidation of SiC powder in an industrial spark plasma sintering device. Specially designed sacrificial dies heat the pre-compacted SiC powder specimens to a critical temperature before applying any voltage to the powder volume and allowing the electrode-punches of the SPS device setup to contact the specimens and pass electric current through them under elevated temperatures. The experimental results demonstrate that flash sintering phenomena can be realized using conventional SPS devices. The usage of hybrid heating SPS devices is pointed out as the mainstream direction for the future studies and utilization of the new flash hot pressing (ultra-rapid spark plasma sintering) technique.

  16. Flash CS4: The Missing Manual

    CERN Document Server

    Grover, Chris

    2008-01-01

    Unlock the power of Flash and bring gorgeous animations to life onscreen. Flash CS4: The Missing Manual includes a complete primer on animation, a guided tour of the program's tools and capabilities, lots of new illustrations, and more details on working with video. Beginners will learn to use the software in no time, and experienced Flash designers will improve their skills.

  17. Evaluation of Flash Bainite in 4130 Steel

    Science.gov (United States)

    2011-07-01

    Technical Report ARWSB-TR-11011 Evaluation of Flash Bainite in 4130 Steel G. Vigilante M. Hespos S. Bartolucci...4. TITLE AND SUBTITLE Evaluation of Flash Bainite in 4130 Steel 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...STATEMENT 13. SUPPLEMENTARY NOTES 14. ABSTRACT ARDEC independently evaluated a Flash Bainite process developed by Gary Cola, Jr., Sirius Protection

  18. Jaan Toomik ajakirjas Flash Art

    Index Scriptorium Estoniae

    1999-01-01

    Kunstiajakirja "Flash Art" maikuu numbris Ando Keskküla artikkel, mis annab ülevaate J. Toomiku loomingust ja peatub pikemalt tema olulisematel töödel. 10. juunist J. Toomiku isiknäitus Londoni fotograafide galeriis. Eksponeeritud video "Uisutaja"

  19. Ingmar Muusikuse foto Flash Artis

    Index Scriptorium Estoniae

    1999-01-01

    Flash Arti 1999. a. oktoobrinumbris virtuaalse näituse rubriigis Ando Keskküla artikkel radikaalsemast eesti kunstist ja kunstielust postsotsialistlikul ajastul. Illustratsiooniks Liina Siibi fotokompositsioonid, Ingmar Muusikuse foto Raoul Kurvitza, Ene-Liis Semperi ja Kiwa Eesti Panga performance'ist

  20. Ingmar Muusikuse foto Flash Artis

    Index Scriptorium Estoniae

    1999-01-01

    Flash Arti 1999. a. oktoobrinumbris virtuaalse näituse rubriigis Ando Keskküla artikkel radikaalsemast eesti kunstist ja kunstielust postsotsialistlikul ajastul. Illustratsiooniks Liina Siibi fotokompositsioonid, Ingmar Muusikuse foto Raoul Kurvitza, Ene-Liis Semperi ja Kiwa Eesti Panga performance'ist

  1. Jaan Toomik ajakirjas Flash Art

    Index Scriptorium Estoniae

    1999-01-01

    Kunstiajakirja "Flash Art" maikuu numbris Ando Keskküla artikkel, mis annab ülevaate J. Toomiku loomingust ja peatub pikemalt tema olulisematel töödel. 10. juunist J. Toomiku isiknäitus Londoni fotograafide galeriis. Eksponeeritud video "Uisutaja"

  2. Potential energy surface of the photolysis of isocyanic acid HNCO

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The dissociation curves of the photolysis of the isocyanic acidHNCOHN+CO corresponding to the ground state (S0), the first triplet excited state (T1) and the first singlet excited state (S1) have been studied respectively at the UHF/6-311G** and CIS/6-311G** levels using ab initio method. The energy surface crossing points, S1/T1, T1/S0 and S1/S0, have been found and the characteristics of the energy minimum crossing point were given, based on which, the changes of the crossing points' geometries along the lower electronic energy surface and its end-result have been located according to the steepest descent principle. The computational result indicates that the photolysis of the isocyanic acid HNCOHN+CO has three competitive reaction channels ((A)-(C)), and from the kinetic piont of view, channel (A) is the most advantageous.

  3. Solar Photolysis and Photocatalytic Decolorization of Thymol Blue

    Directory of Open Access Journals (Sweden)

    Falah H. Hussein

    2008-01-01

    Full Text Available The photolysis and photocatalytic decolorization of an aqueous propane-2-ol solution of thymol blue(TB (Phenol, 4,4'-(3H-2,1-benzoxathiol-3-ylidenebis(5-methyl-2-(1-methylethyl-,S,S-dioxide; Thymolsulfonpthalein (C27H30O5S,were carried out under natural weathering conditions. Direct photolysis of TB solution of concentration 4.3X10−3 M degraded 37.1% of the colored solution after two hours of solar irradiation, however, the solar photocatalytic decolorization percentage reached 79.04% and 86.21% after the addition of zinc oxide and titanium dioxide, respectively, for the same period. The degradation percentages were investigated by monitoring the dye decolorization spectrophotometrically. The decolorization rates of TB are markedly related with amount of hydroxyl radical formed. A suitable mechanism for the mineralization of TB has been proposed.

  4. Observers can reliably identify illusory flashes in the illusory flash paradigm.

    Science.gov (United States)

    van Erp, Jan B F; Philippi, Tom G; Werkhoven, Peter

    2013-04-01

    In the illusory flash paradigm, a single flash may be experienced as two flashes when accompanied by two beeps or taps, and two flashes may be experienced as a single flash when accompanied by one beep or tap. The classic paradigm restricts responses to '1' and '2' (2-AFC), ignoring possible qualitative differences between real and illusory flashes and implicitly assuming that illusory flashes are indistinguishable from real flashes. We added a third response category 'different from that of either 1 or 2 flashes' (3-AFC). Eight naïve and 6 experienced observers responded to 160 real and 160 illusory flash trials. Experienced observers were exposed to 1,200 trials before the experiment but without receiving feedback on their performance. The third response category was used for only 4 % of the real flash trials and for 44 % of the illusory flash trials. Experienced observers did so more often (78 %) than naïve observers (18 %). This shows that observers can reliably identify illusory flashes and indicates that mere exposure to illusory flash trials (without feedback) is enough to detect and classify potential qualitative differences between real and illusory flashes.

  5. Menopausal hot flashes: a review of physiology and biosociocultural perspective on methods of assessment.

    Science.gov (United States)

    Kronenberg, Fredi

    2010-07-01

    Hot flashes continue to be a troublesome problem for menopausal women the world over. After >50 y of research, we still do not understand the etiology and mechanism of hot flashes, nor do we know how estrogen, the major pharmaceutical treatment, works to reduce hot flashes. We are gaining insight into sociocultural complexities that may affect how and whether women report hot flashes. And we are becoming more sophisticated in our research tools (be it questionnaires, physiological monitors, or brain imaging techniques). New aspects of hot flash research, including neuroimaging and the study of genetic polymorphisms, when combined with increasingly nuanced ways of asking questions of culturally distinct populations, provide challenges but rich complexity from which a better understanding will emerge.

  6. On multiphase negative flash for ideal solutions

    DEFF Research Database (Denmark)

    Yan, Wei; Stenby, Erling Halfdan

    2012-01-01

    coefficients. It is shown that this inner loop, named here as multiphase negative flash for ideal solutions, can be solved either by Michelsen's algorithm for multiphase normal flash, or by its variation which uses F−1 phase amounts as independent variables. In either case, the resulting algorithm is actually...... simpler than the corresponding normal flash algorithm. Unlike normal flash, multiphase negative flash for ideal solutions can diverge if the feasible domain for phase amounts is not closed. This can be judged readily during the iteration process. The algorithm can also be extended to the partial negative...

  7. uFlip: Understanding Flash IO Patterns

    DEFF Research Database (Denmark)

    Bouganim, Luc; Jonsson, Bjørn; Bonnet, Philippe

    2009-01-01

    want to establish what kind of IOs should be favored (or avoided) when designing algorithms and architectures for flash-based systems. In this paper, we focus on flash IO patterns, that capture relevant distribution of IOs in time and space, and our goal is to quantify their performance. We define u......FLIP, a benchmark for measuring the response time of flash IO patterns. We also present a benchmarking methodology which takes into account the particular characteristics of flash devices. Finally, we present the results obtained by measuring eleven flash devices, and derive a set of design hints that should drive...

  8. Deuterium fractionation in formaldehyde photolysis: chamber experiments and RRKM theory

    Directory of Open Access Journals (Sweden)

    E. J. K. Nilsson

    2013-04-01

    Full Text Available While isotope effects in formaldehyde photolysis are the key link between the δD of methane emissions with the δD of atmospheric in situ hydrogen production, the mechanism and the extent of their pressure dependencies is not adequately described. The pressure dependence of the photolysis rates of the mono- and di-deuterated formaldehyde isotopologues HDCO and D2CO relative to the parent isotopologue H2CO was investigated using RRKM theory and experiment. D2CO and H2CO were photolysed in a static reaction chamber at bath gas pressures of 50, 200, 400, 600 and 1000 mbar; these experiments compliment and extend our earlier work with HDCO vs. H2CO. The UV lamps used for photolysis emit light at wavelengths that mainly dissociate formaldehyde into molecular products, CO and H2 or D2. A model was constructed using RRKM theory to calculate the lifetime of excited formaldehyde on the S0 surface to describe the observed pressure dependent photolytic fractionation of deuterium. The effect of deuteration on the RRKM lifetime of the S0 state is not the main cause of the experimentally observed isotope effect. We propose that there is an additional previously unrecognised isotopic fractionation in the rate of transfer of population from the initially excited S1 state onto the S0 surface.

  9. Photolysis of Carbonyl Diisocyanate: Generation of Isocyanatocarbonyl Nitrene and Diazomethanone.

    Science.gov (United States)

    Liu, Qifan; Li, Hongmin; Wu, Zhuang; Li, Dingqing; Beckers, Helmut; Rauhut, Guntram; Zeng, Xiaoqing

    2016-10-20

    The stepwise decomposition of carbonyl diisocyanate, OC(NCO)2 , has been studied by using IR spectroscopy in solid argon matrices at 16 K. Upon irradiation with an ArF laser (λ=193 nm), carbonyl diisocyanate split off CO and furnished a new carbonyl nitrene, OCNC(O)N, in its triplet ground state. Two conformers of the nitrene, syn and anti, that were derived from the two conformers of OC(NCO)2 (62 % syn-syn and 38 % syn-anti) were identified and characterized by combining IR spectroscopy and quantum chemical calculations. Subsequent irradiation with visible light (λ>395 nm) caused the Curtius rearrangement of the nitrene into OCNNCO. In addition to the expected decomposition products, N2 and CO, further photolysis of OCNNCO with the ArF laser yielded NOCN, through a diazomethanone (NNCO) intermediate. To further validate our proposed reaction mechanism, ArF-laser photolysis of the closely related NNNNCO and cyclo-N2 CO in solid argon matrices were also studied. The observations of NOCN and in situ CO-trapped product OCNNCO provided indirect evidence to support the initial generation of NNCO as a common intermediate during the laser photolysis of OCNNCO, NNNNCO, and cyclo-N2 CO. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. EMERGING TECHNOLOGY REPORT: BENCH-SCALE TESTING OF PHOTOLYSIS, CHEMICAL OXIDATION AND BIODEGRADATION OF PCB CONTAMINATED SOILS AND PHOTOLYSIS OF TCDD CONTAMINATED SOILS

    Science.gov (United States)

    This report presents the results of bench-scale testing on degradation of 2,3,7,8-TCDD using W photolysis, and PCB degradation using UV photolysis, chemical oxidation and biological treatment. Bench-scale tests were conducted to investigate the feasibility of a two-phase detoxifi...

  11. From Sulfide Flash Smelting to a Novel Flash Ironmaking Technology

    Science.gov (United States)

    Sohn, Hong Yong

    A novel flash ironmaking technology is under development at the University of Utah under the support of U.S. Department of Energy (DOE) and American Iron and Steel Institute (AISI). The history of the development from the conception of the idea to the current status will be discussed. The flash ironmaking process produces iron directly from fine iron ore concentrates without requiring cokemaking and pelletization/sintering, which will enable the technology to significantly reduce energy consumption and carbon dioxide emissions compared with blast furnace ironmaking. Unlike other gas-based ironmaking processes, this technology will not suffer from the problems of solid sticking and fusion. Current work is focused on the method of supplying the energy required to maintain the necessary temperature, as an intermediate step to determine the scalability for larger, industrial-scale pilot trials.

  12. Measuring and Estimating Normalized Contrast in Infrared Flash Thermography

    Science.gov (United States)

    Koshti, Ajay M.

    2013-01-01

    Infrared flash thermography (IRFT) is used to detect void-like flaws in a test object. The IRFT technique involves heating up the part surface using a flash of flash lamps. The post-flash evolution of the part surface temperature is sensed by an IR camera in terms of pixel intensity of image pixels. The IR technique involves recording of the IR video image data and analysis of the data using the normalized pixel intensity and temperature contrast analysis method for characterization of void-like flaws for depth and width. This work introduces a new definition of the normalized IR pixel intensity contrast and normalized surface temperature contrast. A procedure is provided to compute the pixel intensity contrast from the camera pixel intensity evolution data. The pixel intensity contrast and the corresponding surface temperature contrast differ but are related. This work provides a method to estimate the temperature evolution and the normalized temperature contrast from the measured pixel intensity evolution data and some additional measurements during data acquisition.

  13. Synthesis of binary iron-carbon nanoparticles by UV laser photolysis of Fe(CO)5 with various hydrocarbons

    Science.gov (United States)

    Eremin, A. V.; Gurentsov, E. V.; Musikhin, S. A.

    2016-10-01

    In this study the laser photolysis of the mixtures containing vapors of various hydrocarbons and iron pentacarbonyl was implemented to nanoparticle formation. The radiation source used for photo-dissociation of precursors was a pulsed Nd:Yag laser operated at a wavelength of 266 nm. Under UV radiation the molecules of Fe(CO)5 decomposed, forming atomic iron vapor and unsaturated carbonyls at well-known and readily controllable parameters. The subsequent condensation of supersaturated metal vapor resulted in small iron clusters and nanoparticles formation. The growth process of the nanoparticles was observed by a method of laser light extinction. Laser induced incandescence technique was applied for particle sizing during the process of their formation. Additionally nanoparticle samples were investigated by a transmission electron microscope. The particle size distribution was measured by statistical treatment of microphotographs. The elemental analysis by energy-dispersive x-ray spectroscopy and electron diffraction pattern gave the composition and structure of nanoparticles. The core-shell iron-carbon nanoparticles were synthesized by joint laser photolysis of iron pentacarbonyl with benzene and acetylene. The photolysis of the mixtures of toluene, butanol and methane with iron pentacarbonyl revealed in a pure iron particles formation which fast oxidized in air when were extracted out of the reactor.

  14. Wavelength dependence of isotope fractionation in N2O photolysis

    Directory of Open Access Journals (Sweden)

    P. J. Crutzen

    2002-10-01

    Full Text Available In previous reports on isotopic fractionation in the ultraviolet photolysis of nitrous oxide (N2O only enrichments of heavy isotopes in the remaining N2O fraction have been found. However, most direct photolysis experiments have been performed at wavelengths far from the absorption maximum at 182 nm. Here we present high-precision measurements of the 15N and 18O fractionation constants (e in photolysis at 185 nm. Small, but statistically robust depletions of heavy isotopes for the terminal atoms in the linear N2O molecule are found. This means that the absorption cross sections s(15N14N16O and s(14N218O are larger than s(14N216O at this specific wavelength. In contrast, the central N atom becomes enriched in 15N. The corresponding fractionation constants (±1 standard deviation are 15e1 = s(15N14N16O/s(14N216O - 1 = (3.7 ± 0.2%o 18e = s(14N218O/s(14N216O - 1 = (4.5 ± 0.2%o  and   15e2 = s(chem{14N15N16O/s(14N216O - 1 = (-18.6 ± 0.5 %o To our knowledge, this is the first documented case of such a heavy isotope depletion in the photolysis of N2O which supports theoretical models and pioneering vacuum ultraviolet spectroscopic measurements of 15N substituted N2O species that predict fluctuations of e around zero in this spectral region (Selwyn and Johnston, 1981. Such a variability in isotopic fractionation could have consequences for atmospheric models of N2O isotopes since actinic flux varies also strongly over narrow wavelength regions between 175 and 200 nm due to the Schumann-Runge bands of oxygen. However, the spacing between maxima and minima of the fractionation constants and of the actinic flux differ by two orders of magnitude in the wavelength  domain. The wavelength dependence of fractionation constants in N2O photolysis can thus be approximated by a linear fit with negligible consequences on the actual value of the spectrally averaged fractionation constant. In order to establish this linear fit, additional measurements at

  15. Flash Vacuum Pyrolysis of Azides, Triazoles, and Tetrazoles.

    Science.gov (United States)

    Wentrup, Curt

    2017-03-08

    Flash vacuum pyrolysis (FVP) of azides is an extremely valuable method of generating nitrenes and studying their thermal rearrangements. The nitrenes can in many cases be isolated in low-temperature matrices and observed spectroscopically. NH and methyl, alkyl, aralkyl, vinyl, cyano, aryl and N-heteroaryl, acyl, carbamoyl, alkoxycarbonyl, imidoyl, boryl, silyl, phosphonyl, and sulfonyl nitrenes are included. FVP of triazoloazines generates diazomethylazines and azinylcarbenes, which often rearrange to the energetically more stable arylnitrenes. N2 elimination from monocyclic 1,2,3-triazoles can generate iminocarbenes, 1H-azirines, ketenimines, and cyclization products, and 1,2,4-triazoles are precursors of nitrile ylides. Benzotriazoles are preparatively useful precursors of cyanocyclopentadienes, carbazoles, and aza-analogues. FVP of 5-aryltetrazoles can result in double N2 elimination with formation of arylcarbenes or of heteroarylcarbenes, which again rearrange to arylnitrenes. Many 5-substituted and 2,5-disubstituted tetrazoles are excellent precursors of nitrile imines (propargylic, allenic, or carbenic), which are isolable at low temperatures in some cases (e.g., aryl- and silylnitrile imines) or rearrange to carbodiimides. 1,5-Disubstituted tetrazoles are precursors of imidoylnitrenes, which also rearrange to carbodiimides or add intramolecularly to aryl substituents to yield indazoles and related compounds. Where relevant for the mechanistic understanding, pyrolysis under flow conditions or in solution or the solid state will be mentioned. Results of photolysis reactions and computational chemistry complementing the FVP results will also be mentioned in several places.

  16. Spurious dispersion effects at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Prat, Eduard

    2009-07-15

    The performance of the Free-Electron Laser (FEL) process imposes stringent demands on the transverse trajectory and size of the electron beam. Since transverse dispersion changes off-energy particle trajectories and increases the effective beam size, dispersion must be controlled. This thesis treats the concept of dispersion in linacs, and analyses the impact of dispersion on the electron beam and on the FEL process. It presents generation mechanisms for spurious dispersion, quantifying its importance for FLASH (Free-electron Laser in Hamburg) and the XFEL (European X-ray Free-Electron Laser). A method for measuring and correcting dispersion and its implementation in FLASH is described. Experiments of dispersion e ects on the transverse beam quality and on the FEL performance are presented. (orig.)

  17. Multi-stage flash degaser

    Science.gov (United States)

    Rapier, Pascal M.

    1982-01-01

    A multi-stage flash degaser (18) is incorporated in an energy conversion system (10) having a direct-contact, binary-fluid heat exchanger to remove essentially all of the noncondensable gases from geothermal brine ahead of the direct-contact binary-fluid heat exchanger (22) in order that the heat exchanger (22) and a turbine (48) and condenser (32) of the system (10) can operate at optimal efficiency.

  18. Photolysis of polycyclic aromatic hydrocarbons on soil surfaces under UV irradiation

    Institute of Scientific and Technical Information of China (English)

    Chengbin Xu; Dianbo Dong; Xuelian Meng; Xin Su; Xu Zheng; Yaoyao Li

    2013-01-01

    Photolysis of some polycyclic aromatic hydrocarbons (PAHs) on soil surfaces may play an important role in the fate of PAHs in the environment.Photolysis of PAHs on soil surfaces under UV irradiation was investigated.The effects of oxygen,irradiation intensity and soil moisture on the degradation of the three PAHs were observed.The results showed that oxygen,soil moisture and irradiation intensity enhanced the photolysis of the three PAHs on soil surfaces.The degradation of the three PAHs on soil surfaces is related to their absorption spectra and the oxidation-half-wave potential.The photolysis of PAHs on soil surfaces in the presence of oxygen followed pseudo first-order kinetics.The photolysis half-lives ranged from 37.87 days for benzo[a]pyrene to 58.73 days for phenanthrene.The results indicate that photolysis is a successful way to remediate PAHs-contaminated soils.

  19. Trajectory Codes for Flash Memory

    CERN Document Server

    Anxiao,; Langberg, Michael; Schwartz, Moshe; Bruck, Jehoshua

    2010-01-01

    Flash memory is well-known for its inherent asymmetry: the flash-cell charge levels are easy to increase but are hard to decrease. In a general rewriting model, the stored data changes its value with certain patterns. The patterns of data updates are determined by the data structure and the application, and are independent of the constraints imposed by the storage medium. Thus, an appropriate coding scheme is needed so that the data changes can be updated and stored efficiently under the storage-medium's constraints. In this paper, we define the general rewriting problem using a graph model. It extends many known rewriting models such as floating codes, WOM codes, buffer codes, etc. We present a new rewriting scheme for flash memories, called the trajectory code, for rewriting the stored data as many times as possible without block erasures. We prove that the trajectory code is asymptotically optimal in a wide range of scenarios. We also present randomized rewriting codes optimized for expected performance (g...

  20. Laser flash photolysis of chlorine dioxide: Formation and ultraviolet absorption spectrum of Cl sub 2 O sub 3 sup 1

    Energy Technology Data Exchange (ETDEWEB)

    Colussi, A.J.; Redmond, R.W.; Scaiano, J.C. (National Research Council of Canada, Ottawa, Ontario (Canada))

    1989-06-15

    The kinetics of ClO{sub 2} photodecomposition in trichlorofluoromethane solutions induced by 337.1-nm pulses were investigated under various experimental conditions. Instantaneous photochemical bleaching is followed by a slower bleaching which follows pseudo-first-order kinetics and leads to the formation of a long-lived transient species absorbing up to 330 nm with {lambda}{sub max} {approx} 280 nm. At high concentrations of ClO{sub 2} identical amounts of chlorine dioxide are consumed in both stages, revealing that the latter involves stoichiometric reaction of an initially formed intermediate with excess ClO{sub 2}. Addition of tetramethylethylene, a very efficient oxygen atom quencher, had no detectable effect on the kinetics of ClO{sub 2} decay. The intermediate is therefore identified as ClO and the new species as Cl{sub 2}O{sub 3}, chlorine sesquioxide, formed by reaction 5: ClO + ClO{sub 2} {yields} Cl{sub 2}O{sub 3}.

  1. Dynamics of flavin semiquinone protolysis in L-alpha-hydroxyacid-oxidizing flavoenzymes--a study using nanosecond laser flash photolysis.

    Science.gov (United States)

    Lindqvist, Lars; Apostol, Simona; El Hanine-Lmoumene, Chaibia; Lederer, Florence

    2010-02-01

    The reactions of the flavin semiquinone generated by laser-induced stepwise two-photon excitation of reduced flavin have been studied previously (El Hanine-Lmoumene C & Lindqvist L. (1997) Photochem Photobiol 66, 591-595) using time-resolved spectroscopy. In the present work, we have used the same experimental procedure to study the flavin semiquinone in rat kidney long-chain hydroxy acid oxidase and in the flavodehydrogenase domain of flavocytochrome b(2) FDH, two homologous flavoproteins belonging to the family of FMN-dependent L-2-hydroxy acid-oxidizing enzymes. For both proteins, pulsed laser irradiation at 355 nm of the reduced enzyme generated initially the neutral semiquinone, which has rarely been observed previously for these enzymes, and hydrated electron. The radical evolved with time to the anionic semiquinone that is known to be stabilized by these enzymes at physiological pH. The deprotonation kinetics were biphasic, with durations of 1-5 micros and tens of microseconds, respectively. The fast phase rate increased with pH and Tris buffer concentration. However, this increase was about 10-fold less pronounced than that reported for the neutral semiquinone free in aqueous solution. pK(a) values close to that of the free flavin semiquinone were obtained from the transient protolytic equilibrium at the end of the fast phase. The second slow deprotonation phase may reflect a conformational relaxation in the flavoprotein, from the fully reduced to the semiquinone state. The anionic semiquinone is known to be an intermediate in the flavocytochrome b(2) catalytic cycle. In light of published kinetic studies, our results indicate that deprotonation of the flavin radical is not rate-limiting for the intramolecular electron transfer processes in this protein.

  2. Excitation Wavelength Dependent O2 Release from Copper(II)-Superoxide Compounds: Laser Flash-Photolysis Experiments and Theoretical Studies

    Science.gov (United States)

    Saracini, Claudio; Liakos, Dimitrios G.; Zapata Rivera, Jhon E.; Neese, Frank; Meyer, Gerald J.; Karlin, Kenneth D.

    2014-01-01

    Irradiation of the copper(II)-superoxide synthetic complexes [(TMG3tren)CuII(O2)]+ (1) and [(PV-TMPA)CuII(O2)]+ (2) with visible light resulted in direct photo-generation of O2 gas at low temperature (from −40 °C to −70°C for 1 and from −125 °C to −135 °C for 2) in 2-methyltetrahydrofuran (MeTHF) solvent. The yield of O2 release was wavelength dependent: λexc = 436 nm, ϕ = 0.29 (for 1), ϕ = 0.11 (for 2), and λexc = 683 nm, ϕ = 0.035 (for 1), ϕ = 0.078 (for 2), which was followed by fast O2-recombination with [(TMG3tren)CuI]+ (3) and [(PV-TMPA)CuI]+ (4). Enthalpic barriers for O2 re-binding to the copper(I) center (~ 10 kJ mol−1) and for O2 dissociation from the superoxide compound 1 (45 kJ mol−1) were determined. TD-DFT studies, carried out for 1, support the experimental results confirming the dissociative character of the excited states formed upon blue or red light laser excitation. PMID:24428309

  3. Investigation of molecular mechanisms in photodynamic action and radiobiology with nanosecond flash photolysis and pulse radiolysis. Progress report, 1982

    Energy Technology Data Exchange (ETDEWEB)

    Grossweiner, L.I.

    1983-01-01

    Liposomes have been employed as membrane models applicable to photosensitization in phototherapy procedures. The results with 8-methoxypsoralen, the sensitizer in PUVA therapy of psoriasis, show that singlet oxygen generated by near-uv (uv-A) irradiation induces membrane damage leading to lysis. A similar role of singlet oxygen has been shown for photosensitization of liposomes by methylene blue, with the new observation that hydrodynamic forces promote the lytic action initiated by singlet oxygen attack on an unsaturated site of phosphatidylcholine. Liposome photosensitization by hematoporphyrin follows a Type II mechanism mediated by singlet oxygen for low sensitizer concentrations, and a Type I, anoxic, mechanism when the hematoporphyrin is aggregated. Similar concentration effects obtain with hematoporphyrin derivative (hpd), the photosensitizer in photoradiation therapy of malignant tumors. Studies on the components of hpd separated by gel chromatography show that the putative biological active fraction can photosensitize membrane damage under oxic and anoxic conditions. The oxic pathway was suppressed by binding to human serum albumin, as involved in serum transport of hpd prior to localization in tumor tissue. A study on hematoporphyrin photosensitization of targets other than membranes has shown that singlet oxygen is responsible for the photosensitized inactivation of subtilisin BPN' and photooxidation of tryptophan in human and bovine serum albumin. In the case of the serum proteins, the singlet oxygen is generated by the sensitizer-protein complex and it may react with all protein in the system. 11 references.

  4. FLASH2: Operation, beamlines, and photon diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Plönjes, Elke, E-mail: elke.ploenjes@desy.de; Faatz, Bart; Kuhlmann, Marion; Treusch, Rolf [Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg (Germany)

    2016-07-27

    FLASH2, a major extension of the soft X-ray free-electron laser FLASH at DESY, turns FLASH into a multi-user FEL facility. A new undulator line is located in a separate accelerator tunnel and driven additionally by the FLASH linear accelerator. First lasing of FLASH2 was achieved in August 2014 with simultaneous user operation at FLASH1. The new FLASH2 experimental hall offers space for up to six experimental end stations, some of which will be installed permanently. The wide wavelength range spans from 4-60 nm and 0.8 nm in the 5{sup th} harmonic and in the future deep into the water window in the fundamental. While this is of high interest to users, it is challenging from the beamline instrumentation point of view. Online diagnostics - which are mostly pulse resolved - for beam intensity, position, wavelength, wave front, and pulse length have been to a large extent developed at FLASH(1) and have now been optimized for FLASH2. Pump-probe facilities for XUV-XUV, XUV optical and XUV-THz experiments will complete the FLASH2 user facility.

  5. Congenital heart disease in adults: Quantitative and qualitative evaluation of IR FLASH and IR SSFP MRA techniques using a blood pool contrast agent in the steady state and comparison to first pass MRA.

    Science.gov (United States)

    Febbo, Jennifer A; Galizia, Mauricio S; Murphy, Ian G; Popescu, Andrada; Bi, Xiaoming; Turin, Alexander; Collins, Jeremy; Markl, Michael; Edelman, Robert R; Carr, James C

    2015-10-01

    To evaluate magnetic resonance angiography sequences during the contrast steady-state (SS-MRA) using inversion recovery (IR) with fast low-angle shot (IR-FLASH) or steady-state free precession (IR-SSFP) read-outs, following the injection of a blood-pool contrast agent, and compare them to first-pass MR angiography (FP-MRA) in adults with congenital heart disease (CHD). Twenty-three adult patients with CHD who underwent both SS-MRA and FP-MRA using a 1.5-T scanner were retrospectively identified. Signal-to-noise and contrast-to-noise ratios were obtained at eight locations within the aorta and pulmonary vessels.. Image quality and the presence of artifacts were subjectively assessed by two radiologists. The presence of pathology was noted and given a confidence score. There was no difference in vessel dimensions among the sequences. IR-SSFP showed better image quality and fewer artifacts than IR-FLASH and FP-MRA. Confidence scores were significantly higher for SS-MRA compared to FP-MRA. Seven cases (30.4%) had findings detected at SS-MRA that were not detected at FP-MRA, and 2 cases (8.7%) had findings detected by IR-SSFP only. SS-MRA of the thoracic vasculature using a blood pool contrast agent offers superior image quality and reveals more abnormalities compared to standard FP-MRA in adults with CHD, and it is best achieved with an IR-SSFP sequence. These sequences could lead to increased detection rates of abnormalities and provide a simpler protocol image acquisition. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  6. Flash programming for the social & behavioral sciences a simple guide to sophisticated online surveys and experiments

    CERN Document Server

    Weinstein, Yana

    2012-01-01

    Adobe Flash is one of the most popular languages for animated web content, and recently social and behavioral scientists have started to take advantage of it to collect data online. Flash Programming for the Social and Behavioral Sciences: A Simple Guide to Sophisticated Online Surveys and Experiments is a unique, step-by-step guide to using Adobe Flash to develop experiments and other research tools. Each chapter presents a set of techniques required for one aspect of programming an experiment, with students following instructions in italics and working through the code inclu

  7. SEMICONDUCTOR INTEGRATED CIRCUITS A low-voltage sense amplifier for high-performance embedded flash memory

    Science.gov (United States)

    Jiang, Liu; Xueqiang, Wang; Qin, Wang; Dong, Wu; Zhigang, Zhang; Liyang, Pan; Ming, Liu

    2010-10-01

    This paper presents a sense amplifier scheme for low-voltage embedded flash (eFlash) memory applications. The topology of the sense amplifier is based on current mode comparison. Moreover, an offset-voltage elimination technique is employed to improve the sensing performance under a small memory cell current. The proposed sense amplifier is designed based on a GSMC 130 nm eFlash process, and the sense time is 0.43 ns at 1.5 V, corresponding to a 46% improvement over the conventional technologies.

  8. Effects of Chromophoric Dissolved Organic Matter on Anthracene Photolysis Kinetics in Aqueous Solution and Ice.

    Science.gov (United States)

    Malley, Philip P A; Grossman, Jarod N; Kahan, Tara F

    2017-09-27

    We measured photolysis kinetics of the PAH anthracene in aqueous solution, in bulk ice, and at ice surfaces in the presence and absence of chromophoric dissolved organic matter (CDOM). Self-association, which occurs readily at ice surfaces, may be responsible for the faster anthracene photolysis observed there. Photolysis rate constants in liquid water increased under conditions where anthracene self-association was observed. Concomitantly, kinetics changed from first-order to second-order, indicating that the photolysis mechanism at ice surfaces might be different than that in aqueous solution. Other factors that could lead to faster photolysis at ice surfaces were also investigated. Increased photon fluxes due to scattering in the ice samples can account for at most 20% of the observed rate increase, and other factors including singlet oxygen ((1)O2*) production and changes in pH and polarity were determined not to be responsible for the faster photolysis. CDOM (in the form of fulvic acid (FA)) did not affect anthracene photolysis kinetics in aqueous solution but suppressed photolysis in ice cubes and ice granules (by 30% and 56%, respectively). This was primarily due to competitive photon absorption (the inner filter effect). Freeze-concentration (or "salting out") appears to slightly increase the suppressing effects of FA on anthracene photolysis. This may be due to increased competitive photon absorption or to physical interactions between anthracene and FA.

  9. Ecotoxicity of ketoprofen, diclofenac, atenolol and their photolysis byproducts in zebrafish (Danio rerio)

    Energy Technology Data Exchange (ETDEWEB)

    Diniz, M.S., E-mail: mesd@fct.unl.pt [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Salgado, R., E-mail: r.salgado@campus.fct.unl.pt [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); ESTS-IPS, Escola Superior de Tecnologia de Setúbal do Instituto Politécnico de Setúbal, Rua Vale de Chaves, Campus do IPS, Estefanilha, 2910-761 Setúbal (Portugal); Pereira, V.J., E-mail: vanessap@itqb.unl.pt [Instituto de Biologia Experimental e Tecnológica (IBET), Av. da República (EAN), 2784-505 Oeiras (Portugal); Instituto de Tecnologia Química e Biológica (ITQB)—Universidade Nova de Lisboa (UNL), Estação Agronómica Nacional, Av. da República, 2780-157 Oeiras (Portugal); Carvalho, G., E-mail: gs.carvalho@fct.unl.pt [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Instituto de Biologia Experimental e Tecnológica (IBET), Av. da República (EAN), 2784-505 Oeiras (Portugal); Oehmen, A., E-mail: a.oehmen@fct.unl.pt [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Reis, M.A.M., E-mail: amr@fct.unl.pt [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Noronha, J.P., E-mail: jpnoronha@fct.unl.pt [REQUIMTE/CQFB, Chemistry Department, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)

    2015-02-01

    The occurrence of pharmaceutical compounds in wastewater treatment plants and surface waters has been detected worldwide, constituting a potential risk for aquatic ecosystems. Adult zebrafish, of both sexes, were exposed to three common pharmaceutical compounds (atenolol, ketoprofen and diclofenac) and their UV photolysis by-products over seven days. The results show that diclofenac was removed to concentrations < LOD after 5 min of UV irradiation. The oxidative stress response of zebrafish to pharmaceuticals and their photolysis by-products was evaluated through oxidative stress enzymes (glutathione-S-transferase, catalase, superoxide dismutase) and lipid peroxidation. Results suggest that the photolysis by-products of diclofenac were more toxic than those from the other compounds tested, showing an increase in GST and CAT levels, which are also supported by higher MDA levels. Overall, the toxicity of waters containing atenolol and ketoprofen was reduced after the parent compounds were transformed by photolysis, whereas the toxicity increased significantly from the by-products generated through diclofenac photolysis. Therefore, diclofenac photolysis would possibly necessitate higher irradiation time to ensure that the associated by-products are completely degraded to harmless form(s). - Highlights: • Toxicity evaluated for 3 common pharmaceuticals (atenolol, ketoprofen and diclofenac). • Toxicity assessed for the pharmaceuticals and UV photolysis by-products in zebrafish. • Diclofenac photolysis by-products are more toxic than the parent compound. • Ketoprofen and atenolol show stronger oxidative stress response than by-products. • UV photolysis should ensure full removal of diclofenac metabolites to avoid toxicity.

  10. Ecotoxicity of ketoprofen, diclofenac, atenolol and their photolysis byproducts in zebrafish (Danio rerio).

    Science.gov (United States)

    Diniz, M S; Salgado, R; Pereira, V J; Carvalho, G; Oehmen, A; Reis, M A M; Noronha, J P

    2015-02-01

    The occurrence of pharmaceutical compounds in wastewater treatment plants and surface waters has been detected worldwide, constituting a potential risk for aquatic ecosystems. Adult zebrafish, of both sexes, were exposed to three common pharmaceutical compounds (atenolol, ketoprofen and diclofenac) and their UV photolysis by-products over seven days. The results show that diclofenac was removed to concentrationsketoprofen was reduced after the parent compounds were transformed by photolysis, whereas the toxicity increased significantly from the by-products generated through diclofenac photolysis. Therefore, diclofenac photolysis would possibly necessitate higher irradiation time to ensure that the associated by-products are completely degraded to harmless form(s).

  11. Novel approach for low-cost muzzle flash detection system

    Science.gov (United States)

    Voskoboinik, Asher

    2008-04-01

    A low-cost muzzle flash detection based on CMOS sensor technology is proposed. This low-cost technology makes it possible to detect various transient events with characteristic times between dozens of microseconds up to dozens of milliseconds while sophisticated algorithms successfully separate them from false alarms by utilizing differences in geometrical characteristics and/or temporal signatures. The proposed system consists of off-the-shelf smart CMOS cameras with built-in signal and image processing capabilities for pre-processing together with allocated memory for storing a buffer of images for further post-processing. Such a sensor does not require sending giant amounts of raw data to a real-time processing unit but provides all calculations in-situ where processing results are the output of the sensor. This patented CMOS muzzle flash detection concept exhibits high-performance detection capability with very low false-alarm rates. It was found that most false-alarms due to sun glints are from sources at distances of 500-700 meters from the sensor and can be distinguished by time examination techniques from muzzle flash signals. This will enable to eliminate up to 80% of falsealarms due to sun specular reflections in the battle field. Additional effort to distinguish sun glints from suspected muzzle flash signal is made by optimization of the spectral band in Near-IR region. The proposed system can be used for muzzle detection of small arms, missiles and rockets and other military applications.

  12. Search Engine Optimization for Flash Best Practices for Using Flash on the Web

    CERN Document Server

    Perkins, Todd

    2009-01-01

    Search Engine Optimization for Flash dispels the myth that Flash-based websites won't show up in a web search by demonstrating exactly what you can do to make your site fully searchable -- no matter how much Flash it contains. You'll learn best practices for using HTML, CSS and JavaScript, as well as SWFObject, for building sites with Flash that will stand tall in search rankings.

  13. Adobe Flash Professional CS6 digital classroom

    CERN Document Server

    Team, AGI Creative

    2012-01-01

    Full-color book and video package teaches you Flash in a flash! If you want to design and maintain dynamic websites with Adobe Flash, this full-color book-and-video training package from expert instructors is the perfect place to start. Fifteen self-paced, step-by-step lessons are accompanied by video tutorials, and this powerful combination helps you master the basics, acquire essential skills, and learn what's new. Making all aspects of Flash less intimidating, this superb training tool covers topics such as using layers to build animation sequences, creating interactive web

  14. Flash CS5 The Missing Manual

    CERN Document Server

    Grover, Chris

    2010-01-01

    Once you know how to use Flash, you can create everything from simple animations to high-end desktop applications, but it's a complex tool that can be difficult to master on your own-unless you have this Missing Manual. This book will help you learn all you need to know about Flash CS5 to create animations that bring your ideas to life. Learn animation basics. Find everything you need to know to get started with FlashMaster the Flash tools. Learn the animation and effects toolset, with clear explanations and hands-on examplesUse 3D effects. Rotate and put objects in motion in three dimensions

  15. Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Meusinger, Carl; Johnson, Matthew S. [Department of Chemistry, University of Copenhagen, Copenhagen (Denmark); Berhanu, Tesfaye A.; Erbland, Joseph; Savarino, Joel, E-mail: jsavarino@lgge.obs.ujf-grenoble.fr [Univ. Grenoble Alpes, LGGE, F-38000 Grenoble (France); CNRS, LGGE, F-38000 Grenoble (France)

    2014-06-28

    Post-depositional processes alter nitrate concentration and nitrate isotopic composition in the top layers of snow at sites with low snow accumulation rates, such as Dome C, Antarctica. Available nitrate ice core records can provide input for studying past atmospheres and climate if such processes are understood. It has been shown that photolysis of nitrate in the snowpack plays a major role in nitrate loss and that the photolysis products have a significant influence on the local troposphere as well as on other species in the snow. Reported quantum yields for the main reaction spans orders of magnitude – apparently a result of whether nitrate is located at the air-ice interface or in the ice matrix – constituting the largest uncertainty in models of snowpack NO{sub x} emissions. Here, a laboratory study is presented that uses snow from Dome C and minimizes effects of desorption and recombination by flushing the snow during irradiation with UV light. A selection of UV filters allowed examination of the effects of the 200 and 305 nm absorption bands of nitrate. Nitrate concentration and photon flux were measured in the snow. The quantum yield for loss of nitrate was observed to decrease from 0.44 to 0.003 within what corresponds to days of UV exposure in Antarctica. The superposition of photolysis in two photochemical domains of nitrate in snow is proposed: one of photolabile nitrate, and one of buried nitrate. The difference lies in the ability of reaction products to escape the snow crystal, versus undergoing secondary (recombination) chemistry. Modeled NO{sub x} emissions may increase significantly above measured values due to the observed quantum yield in this study. The apparent quantum yield in the 200 nm band was found to be ∼1%, much lower than reported for aqueous chemistry. A companion paper presents an analysis of the change in isotopic composition of snowpack nitrate based on the same samples as in this study.

  16. Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry.

    Science.gov (United States)

    Meusinger, Carl; Berhanu, Tesfaye A; Erbland, Joseph; Savarino, Joel; Johnson, Matthew S

    2014-06-28

    Post-depositional processes alter nitrate concentration and nitrate isotopic composition in the top layers of snow at sites with low snow accumulation rates, such as Dome C, Antarctica. Available nitrate ice core records can provide input for studying past atmospheres and climate if such processes are understood. It has been shown that photolysis of nitrate in the snowpack plays a major role in nitrate loss and that the photolysis products have a significant influence on the local troposphere as well as on other species in the snow. Reported quantum yields for the main reaction spans orders of magnitude - apparently a result of whether nitrate is located at the air-ice interface or in the ice matrix - constituting the largest uncertainty in models of snowpack NOx emissions. Here, a laboratory study is presented that uses snow from Dome C and minimizes effects of desorption and recombination by flushing the snow during irradiation with UV light. A selection of UV filters allowed examination of the effects of the 200 and 305 nm absorption bands of nitrate. Nitrate concentration and photon flux were measured in the snow. The quantum yield for loss of nitrate was observed to decrease from 0.44 to 0.003 within what corresponds to days of UV exposure in Antarctica. The superposition of photolysis in two photochemical domains of nitrate in snow is proposed: one of photolabile nitrate, and one of buried nitrate. The difference lies in the ability of reaction products to escape the snow crystal, versus undergoing secondary (recombination) chemistry. Modeled NOx emissions may increase significantly above measured values due to the observed quantum yield in this study. The apparent quantum yield in the 200 nm band was found to be ∼1%, much lower than reported for aqueous chemistry. A companion paper presents an analysis of the change in isotopic composition of snowpack nitrate based on the same samples as in this study.

  17. An experimental study on bioremediation and photolysis of enrofloxacin.

    Science.gov (United States)

    Zamanpour, Ghasem; Mehrabani-Zeinabad, Arjomand

    2014-01-01

    Recent studies have identified the occurrence of a vast number of pharmaceuticals into the municipal wastewater through excreted urine and feces. Some of these pharmaceutical compounds are degraded in the environment. However, there have been reports on the presence of pharmaceutical active compounds in drinking water. Concerns have been raised over the potential adverse effects of these pharmaceuticals on public health and the aquatic environment. In order to investigate the removal process of pharmaceutical enrofloxacin, a unit consisting of a structured packing rotating biological contactor (spRBC) was designed and constructed as a biological treatment unit. The removal rate reached a maximum of 70% in this biological unit. In the meantime, the effect of photolysis process on the effluent of the biological unit was also studied. In the direct photolysis, the removal performance reached 51% and by adding H2O2 the removal efficiency was increased to 87%. The removal efficiency for the entire system including spRBC and an ultraviolet radiation unit was 94%.

  18. A kinetics study of the O({sup 3}P) + CH{sub 3}Cl reaction over the 556-1485 K range by the HTP and LP-ST techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Taeho; Fontijn, A. [Rensselaer Polytechnic Inst., Troy, NY (United States). High-Temperature Reaction Kinetics Lab.; Lim, K.P.; Michael, J.V. [Argonne National Lab., IL (United States)

    1991-12-01

    The high-temperature photochemistry (HTP) and laser photolysis-shock tube (LP-ST) techniques have been combined to study the kinetics of the reaction between ground-state oxygen atoms with CH{sub 3}Cl over the temperature range, 556--1485 K. In the HTP reactor, used for the 556--1291 K range, O atoms were generated by flash photolysis of O{sub 2}, CO{sub 2} or SO{sub 2}, and the atom concentrations were monitored by resonance fluorescence, while with the LP-ST technique, used for the 916--1485 K range, O atoms were generated by the photolysis of either SO{sub 2} or NO with the 193 nm light from a pulsed ArF excimer laser, and atomic resonance absorption spectroscopy (ARAS) was used to monitor [O]{sub t}. In both studies, rate coefficients were derived from the [O] profiles under the pseudo-first-order condition, [O]{much_lt}[CH{sub 3}Cl]. The data obtained by the two techniques are in excellent agreement and are best represented by the expression, k(T) = 2.57 {times} 10{sup {minus}11} (T/K){sup 0.31} exp({minus}5633 K/T) cm{sup 3} molecule{sup {minus}1} s{sup {minus}1} with a 2{sigma} precision varying from {plus_minus}6 {plus_minus}22% and an estimated 2{sigma} accuracy of {plus_minus}21% to {plus_minus}30%, depending on temperature. The rate coefficients for the title reaction are essentially identical to those for the O + CH{sub 4} reaction over the observed temperature range, the reasons for which are discussed.

  19. A kinetics study of the O( sup 3 P) + CH sub 3 Cl reaction over the 556-1485 K range by the HTP and LP-ST techniques

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Taeho; Fontijn, A. (Rensselaer Polytechnic Inst., Troy, NY (United States). High-Temperature Reaction Kinetics Lab.); Lim, K.P.; Michael, J.V. (Argonne National Lab., IL (United States))

    1991-12-01

    The high-temperature photochemistry (HTP) and laser photolysis-shock tube (LP-ST) techniques have been combined to study the kinetics of the reaction between ground-state oxygen atoms with CH{sub 3}Cl over the temperature range, 556--1485 K. In the HTP reactor, used for the 556--1291 K range, O atoms were generated by flash photolysis of O{sub 2}, CO{sub 2} or SO{sub 2}, and the atom concentrations were monitored by resonance fluorescence, while with the LP-ST technique, used for the 916--1485 K range, O atoms were generated by the photolysis of either SO{sub 2} or NO with the 193 nm light from a pulsed ArF excimer laser, and atomic resonance absorption spectroscopy (ARAS) was used to monitor (O){sub t}. In both studies, rate coefficients were derived from the (O) profiles under the pseudo-first-order condition, (O){much lt}(CH{sub 3}Cl). The data obtained by the two techniques are in excellent agreement and are best represented by the expression, k(T) = 2.57 {times} 10{sup {minus}11} (T/K){sup 0.31} exp({minus}5633 K/T) cm{sup 3} molecule{sup {minus}1} s{sup {minus}1} with a 2{sigma} precision varying from {plus minus}6 {plus minus}22% and an estimated 2{sigma} accuracy of {plus minus}21% to {plus minus}30%, depending on temperature. The rate coefficients for the title reaction are essentially identical to those for the O + CH{sub 4} reaction over the observed temperature range, the reasons for which are discussed.

  20. Hypothalamic-pituitary vascularization in pituitary stalk transection syndrome: is the pituitary stalk really transected? The role of gadolinium-DTPA with spin-echo T1 imaging and turbo-FLASH technique

    Energy Technology Data Exchange (ETDEWEB)

    Genovese, E. [Dept. of Radiology, IRCCS Policlinico S. Matteo, Pavia (Italy); Maghnie, M. [Dept. of Pediatrics, Univ. of Pavia (Italy); Beluffi, G. [Dept. of Radiodiagnosis, Section of Pediatric Radiology, IRCCS Policlinico S. Matteo, Pavia (Italy); Villa, A. [Dept. of Radiology, IRCCS Policlinico S. Matteo, Pavia (Italy); Sammarchi, L. [Dept. of Radiology, IRCCS Policlinico S. Matteo, Pavia (Italy); Severi, F. [Dept. of Pediatrics, Univ. of Pavia (Italy); Campani, R. [Dept. of Radiology, IRCCS Policlinico S. Matteo, Pavia (Italy)

    1997-01-01

    We examined 14 patients, aged 10-25 years, with idiopathic hypopituitarism. All presented an ectopic posterior pituitary at the median eminence with a hypoplastic anterior pituitary on magnetic resonance imaging (MRI). Eight patients had isolated growth hormone deficit (IGHD) and six had multiple hormone deficits (MPHD). Unenhanced MRI showed the pituitary stalk, which was extremely thin, in only three patients, while T1-weighted images obtained after intravenous injection of gadopentetate dimeglumine (Gd-DTPA) showed a thin pituitary stalk in seven patients (six with IGHD and one with MPHD), demonstrating a preserved vascular component of the stalk. MRI with Gd-DTPA was more sensitive than unenhanced MRI in detecting the pituitary stalk in patients with hypopituitarism with an ectopic posterior pituitary: the stalk was demonstrated in 50 % of the cases (seven patients), versus 21.4 % (three patients) by unenhanced MRI. The dynamic study of the hypothalamo-hypophyseal axis performed with turbo-FLASH sequences after bolus injection of Gd-DTPA showed the residual anterior pituitary to have arterial enhancement times, which suggests that an arterial system compensates for the absent or diminished blood supply from the portal system, independent of stalk detection. (orig.). With 5 figs., 1 tab.

  1. Relative tropospheric photolysis rates of acetaldehyde and formaldehyde measured at the European Photoreactor Facility

    DEFF Research Database (Denmark)

    Nilsson, Elna Johanna Kristina; Bache-Andreassen, Lihn; Johnson, Matthew Stanley;

    2009-01-01

    The photolysis rates of HCHO, DCDO, CH3CHO, and CH3CDO are studied by long-path FTIR spectroscopy in natural tropospheric conditions at the European Photoreactor Facility (EUPHORE) in Valencia, Spain. Average relative photolysis rates jHCHO/jDCDO ) 3.15 ( 0.08 and jCH3CHO/jCH3CDO ) 1.26 ( 0...

  2. Rh-flash acquisition card

    CERN Document Server

    Bourrion, O

    2003-01-01

    The rh-flash card main purpose is to convert and store the image of the analog data present at input into an output buffer, namely in a given timing window besides a stop signal (like a digital oscilloscope). It is conceived in VME format 1U wide with an additional connector. Novelty of this card is its ability to sample at a high frequency, due to flash coders, and this at a high repetition rate. To do that the card allows the storage of the data considered 'useful' and that is done by storing only the data exceeding a certain threshold. This can be useful for instance for viewing peaks in a spectrum, and obtaining their relative location. The goal is to stock and process the data sampled before and after the arrival of a stop signal (what entails a storage depth). A threshold is defined and any peak exceeding its level will really be stored in the output buffer which is readable through the VME bus. The peak values will be stored as well as m preceding and n subsequent values (both programmable). Obviously,...

  3. Flash Expansion Threshold in Whirligig Swarms.

    Directory of Open Access Journals (Sweden)

    William L Romey

    Full Text Available In the selfish herd hypothesis, prey animals move toward each other to avoid the likelihood of being selected by a predator. However, many grouped animals move away from each other the moment before a predator attacks. Very little is known about this phenomenon, called flash expansion, such as whether it is triggered by one individual or a threshold and how information is transferred between group members. We performed a controlled experiment with whirligig beetles in which the ratio of sighted to unsighted individuals was systematically varied and emergent flash expansion was measured. Specifically, we examined: the percentage of individuals in a group that startled, the resulting group area, and the longevity of the flash expansion. We found that one or two sighted beetles in a group of 24 was not enough to cause a flash expansion after a predator stimulus, but four sighted beetles usually initiated a flash expansion. Also, the more beetles that were sighted the larger the resulting group area and the longer duration of the flash expansion. We conclude that flash expansion is best described as a threshold event whose adaptive value is to prevent energetically costly false alarms while quickly mobilizing an emergent predator avoidance response. This is one of the first controlled experiments of flash expansion, an important emergent property that has applications to understanding collective motion in swarms, schools, flocks, and human crowds. Also, our study is a convincing demonstration of social contagion, how the actions of one individual can pass through a group.

  4. On Coding Efficiency for Flash Memories

    CERN Document Server

    Ma, Xudong

    2012-01-01

    Recently, flash memories have become a competitive solution for mass storage. The flash memories have rather different properties compared with the rotary hard drives. That is, the writing of flash memories is constrained, and flash memories can endure only limited numbers of erases. Therefore, the design goals for the flash memory systems are quite different from these for other memory systems. In this paper, we consider the problem of coding efficiency. We define the "coding-efficiency" as the amount of information that one flash memory cell can be used to record per cost. Because each flash memory cell can endure a roughly fixed number of erases, the cost of data recording can be well-defined. We define "payload" as the amount of information that one flash memory cell can represent at a particular moment. By using information-theoretic arguments, we prove a coding theorem for achievable coding rates. We prove an upper and lower bound for coding efficiency. We show in this paper that there exists a fundamen...

  5. Millimeter/submillimeter Spectroscopy to Measure the Branching Ratios for Methanol Photolysis

    Science.gov (United States)

    McCabe, Morgan N.; Powers, Carson Reed; Zinga, Samuel; Widicus Weaver, Susanna L.

    2016-06-01

    Methanol is one of the most abundant and important molecules in the interstellar medium, playing a key role in driving more complex organic chemistry both on grain surfaces and through gas-phase ion-molecule reactions. Methanol photolysis produces many radicals such as hydroxyl, methoxy, hydroxymethyl, and methyl that may serve as the building blocks for more complex organic chemistry in star-forming regions. The branching ratios for methanol photolysis may govern the relative abundances of many of the more complex species already detected in these environments. However, no direct, comprehensive, quantitative measurement of methanol photolysis branching ratios is available. Using a 193 nm excimer laser, the gas phase photolysis of methanol was studied in the (sub)millimeter range, where the rotational spectroscopic signatures of the photolysis products were probed. Here we present preliminary results from this experiment.

  6. Heat wave flash droughts in decline

    Science.gov (United States)

    Mo, Kingtse C.; Lettenmaier, Dennis P.

    2015-04-01

    Flash drought is a term that was popularized during rapidly evolving droughts in the Central U.S. in 2012 that were associated with heat waves. We posit that there are two kinds of flash droughts, and we will focus on heat wave flash droughts, of which the 2012 events were typical. We find, based on an analysis of temperature observations and model-reconstructed soil moisture (SM) and evapotranspiration from 1916 to 2013, that heat wave flash droughts in the conterminous U.S. (CONUS) are most likely to occur over the Midwest and the Pacific Northwest during the growing season. We also find that the number of such events across the CONUS has been decreasing over the last century but rebounded after 2011. The long-term downward trends appear to be associated with generally increasing trends in SM resulting from increasing trends in precipitation over the areas where heat wave flash droughts are most likely to occur.

  7. Economic assessment of flash co-pyrolysis of short rotation coppice and biopolymer waste streams.

    Science.gov (United States)

    Kuppens, T; Cornelissen, T; Carleer, R; Yperman, J; Schreurs, S; Jans, M; Thewys, T

    2010-12-01

    The disposal problem associated with phytoextraction of farmland polluted with heavy metals by means of willow requires a biomass conversion technique which meets both ecological and economical needs. Combustion and gasification of willow require special and costly flue gas treatment to avoid re-emission of the metals in the atmosphere, whereas flash pyrolysis mainly results in the production of (almost) metal free bio-oil with a relatively high water content. Flash co-pyrolysis of biomass and waste of biopolymers synergistically improves the characteristics of the pyrolysis process: e.g. reduction of the water content of the bio-oil, more bio-oil and less char production and an increase of the HHV of the oil. This research paper investigates the economic consequences of the synergistic effects of flash co-pyrolysis of 1:1 w/w ratio blends of willow and different biopolymer waste streams via cost-benefit analysis and Monte Carlo simulations taking into account uncertainties. In all cases economic opportunities of flash co-pyrolysis of biomass with biopolymer waste are improved compared to flash pyrolysis of pure willow. Of all the biopolymers under investigation, polyhydroxybutyrate (PHB) is the most promising, followed by Eastar, Biopearls, potato starch, polylactic acid (PLA), corn starch and Solanyl in order of decreasing profits. Taking into account uncertainties, flash co-pyrolysis is expected to be cheaper than composting biopolymer waste streams, except for corn starch. If uncertainty increases, composting also becomes more interesting than flash co-pyrolysis for waste of Solanyl. If the investment expenditure is 15% higher in practice than estimated, the preference for flash co-pyrolysis compared to composting biopolymer waste becomes less clear. Only when the system of green current certificates is dismissed, composting clearly is a much cheaper processing technique for disposing of biopolymer waste.

  8. Report on in-situ studies of flash sintering of uranium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Raftery, Alicia Marie [MST-8: MATERIALS SCIENCE IN RADIATION & DYNAMICS EXTREMES

    2017-01-24

    Flash sintering is a novel type of field assisted sintering that uses an electric field and current to provide densification of materials on very short time scales. The potential for field assisted sintering techniques to be used in producing nuclear fuel is gaining recognition due to the potential economic benefits and improvements in material properties. The flash sintering behavior has so far been linked to applied and material parameters, but the underlying mechanisms active during flash sintering have yet to be identified. This report summarizes the efforts to investigate flash sintering of uranium dioxide using dilatometer studies at Los Alamos National Laboratory and two separate sets of in-situ studies at Brookhaven National Laboratory’s NSLS-II XPD-1 beamline. The purpose of the dilatometer studies was to understand individual parameter (applied and material) effects on the flash behavior and the purpose of the in-situ studies was to better understand the mechanisms active during flash sintering. As far as applied parameters, it was found that stoichiometry, or oxygen-to-metal ratio, has a significant effect on the flash behavior (time to flash and speed of flash). Composite systems were found to have degraded sintering behavior relative to pure UO2. The critical field studies are complete for UO2.00 and will be analyzed against an existing model for comparison. The in-situ studies showed that the strength of the field and current are directly related to the sample temperature, with temperature-driven phase changes occurring at high values. The existence of an ‘incubation time’ has been questioned, due to a continuous change in lattice parameter values from the moment that the field is applied. Some results from the in-situ experiments, which should provide evidence regarding ion migration, are still being analyzed. Some preliminary conclusions can be made from these results with regard to using field assisted sintering to

  9. Hydrogen isotope fractionation in the photolysis of formaldehyde

    Directory of Open Access Journals (Sweden)

    T. S. Rhee

    2007-08-01

    Full Text Available Experiments investigating the isotopic fractionation in the formation of H2 by the photolysis of CH2O under tropospheric conditions are reported and discussed. The deuterium (D depletion in H2 produced is 500(±20‰ with respect to the parent CH2O. We also observed that complete photolysis of CH2O under atmospheric conditions produces H2 that has virtually the same isotopic ratio as that of the parent CH2O. These findings imply that there must be a very strong concomitant isotopic enrichment in the radical channel (CH2O + → CHO + H as compared to the molecular channel (CH2O + → H2 + CO of the photolysis of CH2O in order to balance the relatively small isotopic fractionation in the competing reaction of CH2O with OH. Using a 1-box photochemistry model we calculated the isotopic fractionation factor for the radical channel to be 0.22(±0.08, which is equivalent to a 780(±80‰ enrichment in D of the remaining CH2O. When CH2O is in photochemical steady state, the isotopic ratio of the H2 produced is determined not only by the isotopic fractionation occurring during the photolytical production of H2m but also by overall fractionation for the removal processes of CH2O (αf, and is represented by the ratio of αmf. Applying the isotopic fractionation factors relevant to CH2O photolysis obtained in the present study to the troposphere, the ratio of αmf varies from ~0.8 to ~1.2 depending on the fraction of CH2O that reacts with OH and that produces H2. This range of αmf can render the H2 produced from the photochemical oxidation of CH4 to be enriched in D (with respect to the original CH

  10. Hydrogen isotope fractionation in the photolysis of formaldehyde

    Directory of Open Access Journals (Sweden)

    T. S. Rhee

    2008-03-01

    Full Text Available Experiments investigating the isotopic fractionation in the formation of H2 by the photolysis of CH2O under tropospheric conditions are reported and discussed. The deuterium (D depletion in the H2 produced is 500(±20‰ with respect to the parent CH2O. We also observed that complete photolysis of CH2O under atmospheric conditions produces H2 that has virtually the same isotope ratio as that of the parent CH2O. These findings imply that there must be a very strong concomitant isotopic enrichment in the radical channel (CH2O+hν → CHO+H as compared to the molecular channel (CH2O+hν → H2+CO of the photolysis of CH2O in order to balance the relatively small isotopic fractionation in the competing reaction of CH2O with OH. Using a 1-box photochemistry model we calculated the isotopic fractionation factor for the radical channel to be 0.22(±0.08, which is equivalent to a 780(±80‰ enrichment in D of the remaining CH2O. When CH2O is in photochemical steady state, the isotope ratio of the H2 produced is determined not only by the isotopic fractionation occurring during the photolytical production of H2m but also by overall fractionation for the removal processes of CH2O (αf, and is represented by the ratio of αmf. Applying the isotopic fractionation factors relevant to CH2O photolysis obtained in the present study to the troposphere, the ratio of αmf varies from ~0.8 to ~1.2 depending on the fraction of CH2O that reacts with OH and that produces H2. This range of αmf can render the H2 produced from the photochemical oxidation of CH4 to

  11. Carbamazepine degradation by photolysis and titanium dioxide photocatalysis.

    Science.gov (United States)

    Im, Jong-Kwon; Son, Hyun-Seok; Kang, Young-Min; Zoh, Kyung-Duk

    2012-07-01

    We investigated the degradation of carbamazepine by photolysis/ultraviolet (UV)-C only and titanium dioxide photocatalysis. The degradation of carbamazepine by UV-only and titanium-dioxide-only (adsorption) reactions were inefficient, however, complete degradation of carbamazepine was observed by titanium dioxide photocatalysis within 30 min. The rate of degradation increased as initial carbamazepine concentration decreased, and the removal kinetics fit well with the Langmuir-Hinshelwood model. The addition of methanol, a radical scavenger, decreased carbamazepine removal, suggesting that the hydroxide radical played an important role during carbamazepine degradation. The addition of oxygen during titanium dioxide photocatalysis accelerated hydroxide radical production, thus improving mineralization activity. The photocatalytic degradation was more efficient at a higher pH, whereas the removal of carbamazepine and acridine (a major intermediate) were more efficient under aerobic conditions. The mineralization of carbamazepine during photocatalysis produced various ionic by-products such as ammonium and nitrate by way of nitrogen dioxide.

  12. Terrestrial gamma-ray flashes

    Energy Technology Data Exchange (ETDEWEB)

    Marisaldi, Martino, E-mail: marisaldi@iasfbo.inaf.it [INAF-IASF Bologna, Via Gobetti 101, I-40129 Bologna (Italy); Fuschino, Fabio; Labanti, Claudio [INAF-IASF Bologna, Via Gobetti 101, I-40129 Bologna (Italy); Tavani, Marco [INAF-IASF Roma, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Argan, Andrea [INAF, Viale del Parco Mellini 84, 00136 Roma (Italy); Del Monte, Ettore [INAF-IASF Roma, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Longo, Francesco; Barbiellini, Guido [Dipartimento di Fisica Università di Trieste and INFN Trieste, via A. Valerio 2, I-34127 Trieste (Italy); Giuliani, Andrea [INAF-IASF Milano, Via Bassini 15, I-20133 Milano (Italy); Trois, Alessio [INAF Osservatorio Astronomico di Cagliari, loc. Poggio dei Pini, strada 54, I-09012 Capoterra (Italy); Bulgarelli, Andrea; Gianotti, Fulvio; Trifoglio, Massimo [INAF-IASF Bologna, Via Gobetti 101, I-40129 Bologna (Italy)

    2013-08-21

    Lightning and thunderstorm systems in general have been recently recognized as powerful particle accelerators, capable of producing electrons, positrons, gamma-rays and neutrons with energies as high as several tens of MeV. In fact, these natural systems turn out to be the highest energy and most efficient natural particle accelerators on Earth. Terrestrial Gamma-ray Flashes (TGFs) are millisecond long, very intense bursts of gamma-rays and are one of the most intriguing manifestation of these natural accelerators. Only three currently operative missions are capable of detecting TGFs from space: the RHESSI, Fermi and AGILE satellites. In this paper we review the characteristics of TGFs, including energy spectrum, timing structure, beam geometry and correlation with lightning, and the basic principles of the associated production models. Then we focus on the recent AGILE discoveries concerning the high energy extension of the TGF spectrum up to 100 MeV, which is difficult to reconcile with current theoretical models.

  13. [Nikola Tesla: flashes of inspiration].

    Science.gov (United States)

    Villarejo-Galende, Albero; Herrero-San Martín, Alejandro

    2013-01-16

    Nikola Tesla (1856-1943) was one of the greatest inventors in history and a key player in the revolution that led to the large-scale use of electricity. He also made important contributions to such diverse fields as x-rays, remote control, radio, the theory of consciousness or electromagnetism. In his honour, the international unit of magnetic induction was named after him. Yet, his fame is scarce in comparison with that of other inventors of the time, such as Edison, with whom he had several heated arguments. He was a rather odd, reserved person who lived for his inventions, the ideas for which came to him in moments of inspiration. In his autobiography he relates these flashes with a number of neuropsychiatric manifestations, which can be seen to include migraine auras, synaesthesiae, obsessions and compulsions.

  14. Photolysis of model emerging contaminants in ultra-pure water: kinetics, by-products formation and degradation pathways.

    Science.gov (United States)

    Benitez, F Javier; Acero, Juan L; Real, Francisco J; Roldan, Gloria; Rodriguez, Elena

    2013-02-01

    The photolysis of five frequent emerging contaminants (Benzotriazole, Chlorophene, N,N-diethyl-m-toluamide or DEET, Methylindole, and Nortriptyline HCl) was investigated in ultrapure water under monochromatic ultraviolet radiation at 254 nm and by a combination of UV and hydrogen peroxide. The results revealed that the photolysis rates followed first-order kinetics, with rate constant values depending on the nature of the specific compound, the pH, and the presence or absence of the scavenger tert-butanol. Quantum yields were also determined and values in the range of 53.8 × 10⁻³ - 9.4 × 10⁻³ mol E⁻¹ for Benzotriazole, 525 × 10⁻³ - 469 × 10⁻³ mol E⁻¹ for Chlorophene, 2.8 × 10⁻³ - 0.9 × 10⁻³ mol E⁻¹ for DEET, 108 × 10⁻³ - 165 × 10⁻³ mol E⁻¹ for Methylindole, and 13.8 × 10⁻³ - 15.0 × 10⁻³ mol E⁻¹ for Nortriptyline were obtained. The study also found that the UV/H₂O₂ process enhanced the oxidation rate in comparison to direct photolysis. High-performance liquid chromatography coupled to electrospray ionization quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS) technique was applied to the concentrations evaluation and further identification of the parent compounds and their by-products, which allowed the proposal of the degradation pathways for each compound. Finally, in order to assess the aquatic toxicity in the photodegradation of these compounds, the Vibrio fischeri acute toxicity test was used, and the results indicated an initial increase of this parameter in all cases, followed by a decrease in the specific case of Benzotriazole, DEET, Methylindole, and Chlorophene.

  15. Machine Learning Predictions of Flash Floods

    Science.gov (United States)

    Clark, R. A., III; Flamig, Z.; Gourley, J. J.; Hong, Y.

    2016-12-01

    This study concerns the development, assessment, and use of machine learning (ML) algorithms to automatically generate predictions of flash floods around the world from numerical weather prediction (NWP) output. Using an archive of NWP outputs from the Global Forecast System (GFS) model and a historical archive of reports of flash floods across the U.S. and Europe, we developed a set of ML models that output forecasts of the probability of a flash flood given a certain set of atmospheric conditions. Using these ML models, real-time global flash flood predictions from NWP data have been generated in research mode since February 2016. These ML models provide information about which atmospheric variables are most important in the flash flood prediction process. The raw ML predictions can be calibrated against historical events to generate reliable flash flood probabilities. The automatic system was tested in a research-to-operations testbed enviroment with National Weather Service forecasters. The ML models are quite successful at incorporating large amounts of information in a computationally-efficient manner and and result in reasonably skillful predictions. The system is largely successful at identifying flash floods resulting from synoptically-forced events, but struggles with isolated flash floods that arise as a result of weather systems largely unresolvable by the coarse resolution of a global NWP system. The results from this collection of studies suggest that automatic probabilistic predictions of flash floods are a plausible way forward in operational forecasting, but that future research could focus upon applying these methods to finer-scale NWP guidance, to NWP ensembles, and to forecast lead times beyond 24 hours.

  16. Direct photolysis of carbonyl compounds dissolved in cloud and fog~droplets

    Science.gov (United States)

    Epstein, S. A.; Tapavicza, E.; Furche, F.; Nizkorodov, S. A.

    2013-09-01

    Gas-phase photolysis is an important tropospheric sink for many carbonyl compounds; however the significance of direct photolysis of these compounds dissolved in cloud and fog droplets is uncertain. We develop a theoretical approach to assess the importance of aqueous photolysis for a series of carbonyls that possess carboxyl and hydroxyl functional groups by comparison with rates of other atmospheric processes. We use computationally and experimentally derived effective Henry's law constants, hydration equilibrium parameters, aqueous hydroxyl radical (OH) rate constants, and optical extinction coefficients to identify types of compounds that will (or will not) have competitive aqueous photolysis rates. We also present molecular dynamics simulations designed to estimate gas- and aqueous-phase extinction coefficients of unstudied atmospherically relevant compounds found in d-limonene and isoprene secondary organic aerosol. In addition, experiments designed to measure the photolysis rate of glyceraldehyde, an atmospherically relevant water-soluble organic compound, reveal that aqueous quantum yields are highly molecule-specific and cannot be extrapolated from measurements of structurally similar compounds. We find that only two out of the 92 carbonyl compounds investigated, pyruvic acid and acetoacetic acid, may have aqueous photolysis rates that exceed the rate of oxidation by dissolved OH. For almost all carbonyl compounds lacking α,β-conjugation that were investigated, atmospheric removal by direct photolysis in cloud and fog droplets can be neglected under typical atmospheric conditions.

  17. Direct photolysis of carbonyl compounds dissolved in cloud and fog droplets

    Science.gov (United States)

    Epstein, S. A.; Tapavicza, E.; Furche, F.; Nizkorodov, S. A.

    2013-04-01

    Gas phase photolysis is an important tropospheric sink for many carbonyl compounds, however the significance of direct photolysis of carbonyl compounds dissolved in cloud and fog droplets is uncertain. We develop a theoretical approach to assess the importance of aqueous photolysis for a series of carbonyls that possess carboxyl and hydroxyl functional groups by comparison with rates of other atmospheric processes. We use computationally and experimentally derived Henry's law parameters, hydration equilibrium parameters, aqueous hydroxyl radical (OH) rate constants, and optical extinction coefficients to identify types of compounds that will not have competitive aqueous photolysis rates. We also present molecular dynamics simulations of atmospherically relevant carbonyl compounds designed to estimate gas and aqueous phase extinction coefficients. In addition, experiments designed to measure the photolysis rate of glyceraldehyde, an atmospherically relevant water soluble organic compound, reveal that aqueous quantum yields are highly molecule-specific and cannot be extrapolated from measurements of structurally similar compounds. We find that only three out of the 92 carbonyl compounds investigated, pyruvic acid, 3-oxobutanoic acid, and 3-oxopropanoic acid, may have aqueous photolysis rates that exceed the rate of oxidation by dissolved OH. For almost all carbonyl compounds lacking α, β conjugation, atmospheric removal by direct photolysis in cloud and fog droplets can be neglected.

  18. Flash memory in embedded Java programs

    DEFF Research Database (Denmark)

    Korsholm, Stephan Erbs

    2011-01-01

    This paper introduces a Java execution environment with the capability for storing constant heap data in Flash, thus saving valuable RAM. The extension is motivated by the structure of three industrial applications which demonstrate the need for storing constant data in Flash on small embedded...... devices. The paper introduces the concept of host initialization of constant data to prepare a Flash image of constant data that can be kept outside the heap during runtime. The concept is implemented in an interpreter based Java execution environment....

  19. Evaluation of simulated photolysis rates and their response to solar irradiance variability

    Science.gov (United States)

    Sukhodolov, Timofei; Rozanov, Eugene; Ball, William T.; Bais, Alkiviadis; Tourpali, Kleareti; Shapiro, Alexander I.; Telford, Paul; Smyshlyaev, Sergey; Fomin, Boris; Sander, Rolf; Bossay, Sébastien; Bekki, Slimane; Marchand, Marion; Chipperfield, Martyn P.; Dhomse, Sandip; Haigh, Joanna D.; Peter, Thomas; Schmutz, Werner

    2016-05-01

    The state of the stratospheric ozone layer and the temperature structure of the atmosphere are largely controlled by the solar spectral irradiance (SSI) through its influence on heating and photolysis rates. This study focuses on the uncertainties in the photolysis rate response to solar irradiance variability related to the choice of SSI data set and to the performance of the photolysis codes used in global chemistry-climate models. To estimate the impact of SSI uncertainties, we compared several photolysis rates calculated with the radiative transfer model libRadtran, using SSI calculated with two models and observed during the Solar Radiation and Climate Experiment (SORCE) satellite mission. The importance of the calculated differences in the photolysis rate response for ozone and temperature changes has been estimated using 1-D a radiative-convective-photochemical model. We demonstrate that the main photolysis reactions, responsible for the solar signal in the stratosphere, are highly sensitive to the spectral distribution of SSI variations. Accordingly, the ozone changes and related ozone-temperature feedback are shown to depend substantially on the SSI data set being used, which highlights the necessity of obtaining accurate SSI variations. To evaluate the performance of photolysis codes, we compared the results of eight, widely used, photolysis codes against two reference schemes. We show that, in most cases, absolute values of the photolysis rates and their response to applied SSI changes agree within 30%. However, larger errors may appear in specific atmospheric regions because of differences, for instance, in the treatment of Rayleigh scattering, quantum yields, or absorption cross sections.

  20. Optical pulses, lasers, measuring techniques

    CERN Document Server

    Früngel, Frank B A

    1965-01-01

    High Speed Pulse Technology: Volume II: Optical Pulses - Lasers - Measuring Techniques focuses on the theoretical and engineering problems that result from the capacitor discharge technique.This book is organized into three main topics: light flash production from a capacitive energy storage; signal transmission and ranging systems by capacitor discharges and lasers; and impulse measuring technique. This text specifically discusses the air spark under atmospheric conditions, industrial equipment for laser flashing, and claims for light transmitting system. The application of light impulse sign

  1. Flash co-pyrolysis of biomass with plastic waste

    Energy Technology Data Exchange (ETDEWEB)

    T. Cornelissen; S. Schreurs; G. Reggers; R. Carleer; J. Yperman [Hasselt University, Diepenbeek (Belgium). Lab of Applied Chemistry

    2007-07-01

    The Global Warming, the Kyoto Protocol and the emission of greenhouse gasses such as CO{sub 2} are the topics of environmental pleadings. The world's energy supply is limited due to the depletion of fossil fuels, which are still the most important energy sources consumed. The development of new and renewable energies is the key to change. The flash pyrolysis of biomass is a promising route for the production of solid, liquid and gaseous products. A high liquid production requires very low vapour residence time to minimise secondary reactions. Flash co-pyrolytic techniques, at low temperature, provide an alternative way to dispose and convert waste (like plastics) and biomass into high value feedstock. The specific benefits of this method potentially include: the reduction of the volume of the waste, the recovery of chemicals and the replacement of fossil fuels. Co-pyrolysing of PLA (although a biologically degradable polymer, polylactic acid), with biomass (such as willow) may be an alternative waste treatment option. This research indicates that during the flash co-pyrolysis of PLA and willow (even when contaminated with high amounts of heavy metals) a synergy is attained, resulting in a higher yield of bio-oil with a lower water content. 10 refs., 1 fig.

  2. Does underwater flash photography affect the behaviour, movement and site persistence of seahorses?

    Science.gov (United States)

    Harasti, D; Gladstone, W

    2013-11-01

    The effect of flash photography on seahorse species has never been tested. An experiment was established to test the effect of flash photography and the handling of Hippocampus whitei, a medium-sized seahorse species endemic to Australia, on their behavioural responses, movements and site persistence. A total of 24 H. whitei were utilized in the experiment with eight in each of the three treatments (flash photography, handling and control). The effect of underwater flash photography on H. whitei movements was not significant; however, the effect of handling H. whitei to take a photograph had a significant effect on their short-term behavioural responses to the photographer. Kaplan-Meier log-rank test revealed that there was no significant difference in site persistence of H. whitei from each of the three treatments and that flash photography had no long-term effects on their site persistence. It is concluded that the use of flash photography by divers is a safe and viable technique with H. whitei, particularly if photographs can be used for individual identification purposes.

  3. Modeling of photolysis rates over Europe: impact on chemical gaseous species and aerosols

    Directory of Open Access Journals (Sweden)

    E. Real

    2010-07-01

    Full Text Available This paper evaluates the impact of photolysis rate calculation on European air composition and air quality monitoring. In particular, the impact of cloud parametrisation and the impact of aerosols on photolysis rates are analysed. Photolysis rates are simulated using the Fast-JX photolysis scheme and gas and aerosol concentrations over Europe are simulated with the regional model Polair3D of the Polyphemus platform. The photolysis scheme is first use to update the clear sky tabulation used in the previous Polair3D version. Important differences in photolysis rates are simulated, mainly due to updated cross-sections in the Fast-JX scheme. In the previous Polair3D version, clouds were taken into account by multiplying the clear-sky photolysis rates using a correction factor. In a second stage, the impact of clouds is taken into account more accurately by simulating them directly in the photolysis scheme. Differences in photolysis rates inside clouds are as high as differences between simulations with and without clouds. Outside clouds, the differences are small. The largest difference in gas concentrations is simulated for OH with a mean increase of its tropospheric burden of 4 to 5%.

    To take into account the impact of aerosols on photolysis rates, Polair3D and Fast-JX are coupled. Photolysis rates are updated every hour. Large impact on photolysis rates is observed at the ground, decreasing with altitude. The aerosol species that impact the most photolysis rates is dust especially in South Europe. Strong impact is also observed over anthropogenic emission regions (Paris, The Po and the Ruhr Valley where mainly nitrate and sulphate reduced the incoming radiation. Differences in photolysis rates lead to changes in gas concentrations, with the largest impact simulated for OH and NO concentrations. At the ground, monthly mean concentrations of both species are reduced over Europe by around 10 to 14% and their tropospheric burden by around 10

  4. Flash Point: Evaluation, Experimentation and Estimation

    Science.gov (United States)

    Rowley, J. R.; Freeman, D. K.; Rowley, R. L.; Oscarson, J. L.; Giles, N. F.; Wilding, W. V.

    2010-05-01

    The flash point is an important indicator of the flammability of a chemical. For safety purposes, many data compilations report the lowest value and not the most likely. This practice, combined with improper documentation and poor data storage methods, has resulted in compilations filled with fire-hazard data that are inconsistent with related properties and between members of homologous chemical series. In this study, the flash points reported in the DIPPR® 801 database and more than 1,400 other literature values were critically reviewed based on measurement method, inter-property relations, and trends in chemical series. New measurements for seven compounds illustrate the differences between experimental flash points and data commonly found in fire-hazard compilations. With a critically reviewed set of experimental data, published predictive methods for the flash point were evaluated for accuracy.

  5. 3D Flash LIDAR Space Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Scientific Concepts, Inc (ASC) is a small business, which has developed a compact, eye-safe 3D Flash LIDARTM Camera (FLC) well suited for real-time...

  6. Hot Flashes amd Night Sweats (PDQ)

    Science.gov (United States)

    ... Other Funding Find NCI funding for small business innovation, technology transfer, and contracts Training Cancer Training at ... remedies for hot flashes. These include dong quai , milk thistle , red clover , licorice root extract , and chaste ...

  7. Method for programming a flash memory

    Science.gov (United States)

    Brosky, Alexander R.; Locke, William N.; Maher, Conrado M.

    2016-08-23

    A method of programming a flash memory is described. The method includes partitioning a flash memory into a first group having a first level of write-protection, a second group having a second level of write-protection, and a third group having a third level of write-protection. The write-protection of the second and third groups is disabled using an installation adapter. The third group is programmed using a Software Installation Device.

  8. Hydrodynamic simulations of the core helium flash

    CERN Document Server

    Mocak, M; Weiss, A; Kifonidis, K; 10.1017/S1743921308022813

    2009-01-01

    We describe and discuss hydrodynamic simulations of the core helium flash using an initial model of a 1.25 M_sol star with a metallicity of 0.02 near at its peak. Past research concerned with the dynamics of the core helium flash is inconclusive. Its results range from a confirmation of the standard picture, where the star remains in hydrostatic equilibrium during the flash (Deupree 1996), to a disruption or a significant mass loss of the star (Edwards 1969; Cole & Deupree 1980). However, the most recent multidimensional hydrodynamic study (Dearborn 2006) suggests a quiescent behavior of the core helium flash and seems to rule out an explosive scenario. Here we present partial results of a new comprehensive study of the core helium flash, which seem to confirm this qualitative behavior and give a better insight into operation of the convection zone powered by helium burning during the flash. The hydrodynamic evolution is followed on a computational grid in spherical coordinates using our new version of th...

  9. The free-electron laser FLASH

    Institute of Scientific and Technical Information of China (English)

    Siegfried Schreiber; Bart Faatz

    2015-01-01

    FLASH at DESY, Hamburg, Germany is the first free-electron laser(FEL) operating in the extreme ultraviolet(EUV)and soft x-ray wavelength range. FLASH is a user facility providing femtosecond short pulses with an unprecedented peak and average brilliance, opening new scientific opportunities in many disciplines. The first call for user experiments has been launched in 2005. The FLASH linear accelerator is based on TESLA superconducting technology, providing several thousands of photon pulses per second to user experiments. Probing femtosecond-scale dynamics in atomic and molecular reactions using, for instance, a combination of x-ray and optical pulses in a pump and probe arrangement,as well as single-shot diffraction imaging of biological objects and molecules, are typical experiments performed at the facility. We give an overview of the FLASH facility, and describe the basic principles of the accelerator. Recently,FLASH has been extended by a second undulator beamline(FLASH2) operated in parallel to the first beamline, extending the capacity of the facility by a factor of two.

  10. Ultra-High Speed Fabrication of TiO2 Photoanode by Flash Light for Dye-Sensitized Solar Cell.

    Science.gov (United States)

    Hwang, Hyun-Jun; Kim, Hak-Sung

    2015-07-01

    In this work, a new way to fabricate nanoporous TiO2 photoanode by flash light is demonstrated. TiO2 nanoparticles are sintered on FTO glass by flash light irradiation at room temperature in ambient condition, which is dramatically simple, ultrahigh speed and one-shot large area fabrication process compared to a conventional high temperature (120 °C) thermal sintering process. The effect of the flash light conditions (flash light energy, pulse numbers and pulse duration) on the nanostructures of sintered TiO2 layer, was studied and discussed using several microscopic and spectroscopic characterization techniques such as SEM, FT-IR, XRD and XPS. The sintered TiO2 photoanodes by flash light were used in DSSC and its performance were compared with that of DSSC fabricated by conventional thermal sintering process. It was found that a flash light sintered TiO2 photoanode has efficiency which is similar to that of the thermal sintered photoanode. It is expected that the newly developed flash light sintering technique of TiO2 nanoparticles would be a strong alternative to realize the room temperature and in-situ sintering of photoanode fabrication for outdoor solar cell fabrication.

  11. Flash flood modeling with the MARINE hydrological distributed model

    Directory of Open Access Journals (Sweden)

    V. Estupina-Borrell

    2006-11-01

    anticipated by the French Meteorological Service (Météo France; and (iii the spatially distributed soil and other surface properties viewed from space (land cover map from SPOT or LANDSAT, main rivers, .... The stream flood propagation model simulates flood propagation in main rivers by solving 1-D Saint Venant equations. The data required for this part of the model are the river morphology, topography and roughness. The MARINE model has already been used previously for real time flash floods forecasting in the frame of the PACTES project on "forecasting and anticipation of floods with spatial techniques'' (funded by the CNES and the French Ministry of Research concerning the catastrophic 1999 flash flood that occurred in the South of France. The main advantages of MARINE are its ability to run on insufficiently gauged basins (with the help of satellite information and to run in an operational mode for real-time flood forecasting.

  12. Influence of photolysis on multispectral photoacoustic measurement of nitrogen dioxide concentration.

    Science.gov (United States)

    Tian, Guoxun; Moosmüller, Hans; Arnott, W Patrick

    2013-09-01

    Multispectral photoacoustic instruments are commonly used to measure aerosol and nitrogen dioxide (NO2) light absorption coefficients to determine the radiation budget of the atmosphere. Here a new photoacoustic system is developed to explore the effect of photolysis on the measured signal in a multispectral photoacoustic spectrometer In this system, a 405-nm laser is used primarily as light source for photolysis. Additionally, a well-overlapped 532-nm laser, modulated at the resonant frequency of the photoacoustic instrument, is used to probe the NO2 concentration. As a result, the photolysis effect at 405 nm can be observed by the photoacoustic instrument through the 532-nm laser. This work determines an 11% reduction of the photoacoustic signal caused by the photolysis effect for typical conditions, which needs to be taken into account when calibrating multispectral photoacoustic spectrometers with NO2.

  13. Synthesis and characterization of potential iron–platinum drugs and supplements by laser liquid photolysis

    CSIR Research Space (South Africa)

    Nkosi, SS

    2013-06-01

    Full Text Available , and structure was systematically investigated. Different nanostructures of iron–platinum alloy and chemically disordered iron–platinum L10 phase were obtained without annealing. The prepared precursor solution underwent deep photolysis to polycrystalline iron...

  14. The role of electron donors generated from UV photolysis for accelerating pyridine biodegradation.

    Science.gov (United States)

    Tang, Yingxia; Zhang, Yongming; Yan, Ning; Liu, Rui; Rittmann, Bruce E

    2015-09-01

    Employing an internal circulation baffled biofilm reactor (ICBBR), we evaluated the mechanisms by which photolysis accelerated the biodegradation and mineralization of pyridine (C5 H5 N), a nitrogen-containing heterocyclic compound. We tested the hypothesis that pyridine oxidation is accelerated because a key photolysis intermediate, succinate, is as electron donor that promotes the initial mono-oxygenation of pyridine. Experimentally, longer photolysis time generated more electron-donor products (succinate), which stimulated faster pyridine biodegradation. This pattern was confirmed by directly adding succinate, and the stimulation effect occurred similarly with addition of the same equivalents of acetate and formate. Succinate, whether generated by UV photolysis or added directly, also accelerated mono-oxygenation of the first biodegradation intermediate, 2-hydroxyl pyridine (2HP). 2HP and pyridine were mutually inhibitory in that their mono-oxygenations competed for internal electron donor; thus, the addition of any readily biodegradable donor accelerated both mono-oxygenation steps, as well as mineralization.

  15. High Risk Flash Flood Rainstorm Mapping Based on Regional L-moments Approach

    Science.gov (United States)

    Ding, Hui; Liao, Yifan; Lin, Bingzhang

    2017-04-01

    Difficulties and complexities in elaborating flash flood early-warning and forecasting system prompt hydrologists to develop some techniques to substantially reduce the disastrous outcome of a flash flood in advance. An ideal to specify those areas that are subject at high risk to flash flood in terms of rainfall intensity in a relatively large region is proposed in this paper. It is accomplished through design of the High Risk Flash Flood Rainstorm Area (HRFFRA) based on statistical analysis of historical rainfall data, synoptic analysis of prevailing storm rainfalls as well as the field survey of historical flash flood events in the region. A HRFFRA is defined as the area potentially under hitting by higher intense-precipitation for a given duration with certain return period that may cause a flash flood disaster in the area. This paper has presented in detail the development of the HRFFRA through the application of the end-to-end Regional L-moments Approach (RLMA) to precipitation frequency analysis in combination with the technique of spatial interpolation in Jiangxi Province, South China Mainland. Among others, the concept of hydrometeorologically homogenous region, the precision of frequency analysis in terms of parameter estimation, the accuracy of quantiles in terms of uncertainties and the consistency adjustments of quantiles over durations and space, etc., have been addressed. At the end of this paper, the mapping of the HRFFRA and an internet-based visualized user-friendly data-server of the HRFFRA are also introduced. Key words: HRFFRA; Flash Flood; RLMA; rainfall intensity; Hydrometeorological homogenous region.

  16. Towards a quantitative study of the VUV photolysis of methane: preliminary experiment on trichloromethane

    Science.gov (United States)

    Gans, B.; Boyé-Péronne, S.; Douin, S.; Gauyacq, D.

    2010-01-01

    Photolysis of methane in Titan's stratosphere is the starting point of gas phase carbon chemistry. Quantitative studies of methane photolytic products are of utmost importance for Titan atmosphere models. With this aim, two experimental strategies are presented in this article. Preliminary results demonstrate the possibility of using CRDS absorption coupled with pulsed photolysis on the example of a halogenated derivative of methane: Trichloromethane (CHCl_3).

  17. Intimately coupling of photolysis accelerates nitrobenzene biodegradation, but sequential coupling slows biodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lihui [Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University, Shanghai 200234 (China); Zhang, Yongming, E-mail: zhym@shnu.edu.cn [Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University, Shanghai 200234 (China); Bai, Qi; Yan, Ning; Xu, Hua [Department of Environmental Science and Engineering, College of Life and Environmental Science, Shanghai Normal University, Shanghai 200234 (China); Rittmann, Bruce E. [Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, Tempe, AZ 85287-5701 (United States)

    2015-04-28

    Highlights: • Intimately coupled UV photolysis accelerated nitrobenzene biodegradation. • NB biodegradation was slowed by accumulation of nitrophenol. • Oxalic acid was a key product of UV photolysis. • Oxalic acid accelerated biodegradation of nitrobenzene and nitrophenol by a co-substrate effect. • Intimate coupling of UV and biodegradation accentuated the benefits of oxalic acid. - Abstract: Photo(cata)lysis coupled with biodegradation is superior to photo(cata)lysis or biodegradation alone for removal of recalcitrant organic compounds. The two steps can be carried out sequentially or simultaneously via intimate coupling. We studied nitrobenzene (NB) removal and mineralization to evaluate why intimate coupling of photolysis with biodegradation was superior to sequential coupling. Employing an internal circulation baffled biofilm reactor, we compared direct biodegradation (B), biodegradation after photolysis (P + B), simultaneous photolysis and biodegradation (P&B), and biodegradation with nitrophenol (NP) and oxalic acid (OA) added individually and simultaneously (B + NP, B + OA, and B + NP + OA); NP and OA were NB’s main UV-photolysis products. Compared with B, the biodegradation rate P + B was lower by 13–29%, but intimately coupling (P&B) had a removal rate that was 10–13% higher; mineralization showed similar trends. B + OA gave results similar to P&B, B + NP gave results similar to P + B, and B + OA + NP gave results between P + B and P&B, depending on the amount of OA and NP added. The photolysis product OA accelerated NB biodegradation through a co-substrate effect, but NP was inhibitory. Although decreasing the UV photolysis time could minimize the inhibition impact of NP in P + B, P&B gave the fastest removal of NB by accentuating the co-substrate effect of OA.

  18. Photolysis of oxygen saturated ethers in the presence of Sn (Ⅱ) or Cu (Ⅱ) salts

    Institute of Scientific and Technical Information of China (English)

    施敏

    2000-01-01

    Photolysis of diethyl ether-oxygen charge transfer complex the presence of Sn(Ⅱ) or Cu(Ⅱ) salts gave higher yields of the oxiation products, ethyl acetate, acetaldehyde, ethanol,ethyl formate and methanol compared with those without the salts. In addition, the photolysis of an oxygen saturated tetrahydrofuran (THF) or dibutyl lether solution gave γ-butyro-Their yields were also affected by the addition of Cu(Ⅱ) or Sn(Ⅱ) salts.

  19. Pesticide photolysis in prairie potholes: probing photosensitized processes.

    Science.gov (United States)

    Zeng, Teng; Arnold, William A

    2013-07-02

    Prairie pothole lakes (PPLs) are glacially derived, ecologically important water bodies found in central North America and represent a unique setting in which extensive agriculture occurs within wetland ecosystems. In the Prairie Pothole Region (PPR), elevated pesticide use and increasing hydrologic connectivity have raised concerns about the impact of nonpoint source agricultural pollution on the water quality of PPLs and downstream aquatic systems. Despite containing high dissolved organic matter (DOM) levels, the photoreactivity of the PPL water and the photochemical fate of pesticides entering PPLs are largely unknown. In this study, the photodegradation of sixteen pesticides was investigated in PPL waters sampled from North Dakota, under simulated and natural sunlight. Enhanced pesticide removal rates in the irradiated PPL water relative to the control buffer pointed to the importance of indirect photolysis pathways involving photochemically produced reactive intermediates (PPRIs). The steady-state concentrations of carbonate radical, hydroxyl radical, singlet oxygen, and triplet-excited state DOM were measured and second-order rate constants for reactions of pesticides with these PPRIs were calculated. Results from this study underscore the role of DOM as photosensitizer in limiting the persistence of pesticides in prairie wetlands through photochemical reactions.

  20. Photolysis kinetics and influencing factors of bisphenol S in aqueous solutions.

    Science.gov (United States)

    Cao, Guiping; Lu, Jilai; Wang, Gongying

    2012-01-01

    The photodegradation of bisphenol S (BPS) in aqueous solutions was studied under different conditions. Photolysis and kinetics were investigated, as were the photolysis mechanism and the influences of initial pH value, light source, and environmental substances in water. The results showed that the photolysis of BPS occurred under UV light, and the rate increased with light source intensity. The photolysis of 5.0-50.0 mg/L BPS in water followed first-order kinetics: the rate was gamma = 0.0161C(BPS) under a 40-W UV-lamp, and the degradation half-life was 43.1 min. Due to its absorption of light, direct photolysis of BPS was a predominant pathway for BPS but was not obviously affected by reactive oxygen species. The results confirmed that the photolysis rates of BPS in alkaline water solution were faster than those in acidic and neutral water solution because of the ionization of BPS. The photodegradation rate of BPS increased in the presence of chloride and ferric ions, while the rate was inhibited by nitrate and phosphate in aqueous solution.

  1. Photolysis of three antiviral drugs acyclovir, zidovudine and lamivudine in surface freshwater and seawater.

    Science.gov (United States)

    Zhou, Chengzhi; Chen, Jingwen; Xie, Qing; Wei, Xiaoxuan; Zhang, Ya-nan; Fu, Zhiqiang

    2015-11-01

    Photodegradation is an important elimination process for many pharmaceuticals in surface waters. In this study, photodegradation of three antiviral drugs, acyclovir, zidovudine, and lamivudine, was investigated in pure water, freshwater, and seawater under the irradiation of simulated sunlight. Results showed that zidovudine was easily transformed via direct photolysis, while acyclovir and lamivudine were mainly transformed via indirect photolysis. We found that in freshwater, nitrate enhanced the photodegradation of the three antiviral drugs, bicarbonate promoted the photodegradation of acyclovir, and dissolved organic matter (DOM) accelerated the photolysis of acyclovir and lamivudine. In seawater, the photolysis of acyclovir was not susceptible to Cl(-), Br(-) and ionic strength; however, the photolysis of zidovudine was inhibited by Cl(-) and Br(-), and the photolysis of lamivudine was enhanced by Cl(-), Br(-) and ionic strength. Second-order reaction rate constants for the three antiviral drugs with (1)O2 (k1O2) and OH (kOH) were also measured. These results are important for fate and ecological risk assessment of the antiviral drugs in natural waters.

  2. Photolysis of metal oxides as a source of atoms in planetary exospheres

    Science.gov (United States)

    Valiev, R. R.; Berezhnoy, A. A.; Sidorenko, A. D.; Merzlikin, B. S.; Cherepanov, V. N.

    2017-10-01

    The cross sections of photolysis of LiO, NaO, KO, MgO, and CaO molecules have been calculated by the use of quantum chemistry methods. The maximal values for photolysis cross sections of alkali metal monoxides have the order of 10-17 cm2, and for alkaline earth metal monoxides these values are less on 1-2 orders of the magnitude. The lifetimes of photolysis at 1 astronomical unit are estimated as 5, 3, 60, 70, and 3,000 s for LiO, NaO, KO, MgO, and CaO, respectively. Typical kinetic energies of main peaks of photolysis-generated metal atoms are determined. Impact-produced LiO, NaO, KO, and MgO molecules are destroyed in the lunar and Hermean exospheres almost completely during the first ballistic flight while CaO molecule is more stable against destruction by photolysis. Photolysis-generated metal atoms in planetary exospheres can be detected by performing high-resolution spectral observations of velocity distribution of exospheric metal atoms.

  3. Photolysis kinetics and influencing factors of bisphenol S in aqueous solutions

    Institute of Scientific and Technical Information of China (English)

    Guiping Cao; Jilai Lu; Gongying Wang

    2012-01-01

    The photodegradation of bisphenol S (BPS) in aqueous solutions was studied under different conditions.Photolysis and kinetics were investigated,as were the photolysis mechanism and the influences of initial pH value,light source,and environmental substances in water.The results showed that the photolysis of BPS occurred under UV light,and the rate increased with light source intensity.The photolysis of 5.0-50.0 mg/L BPS in water followed first-order kinetics:the rate was Υ =0.0161Caps under a 40-W UV-lamp,and the degradation half-life was 43.1 min.Due to its absorption of light,direct photolysis of BPS was a predominant pathway for BPS but was not obviously affected by reactive oxygen species.The results confirmed that the photolysis rates of BPS in alkaline water solution were faster than those in acidic and neutral water solution because of the ionization of BPS.The photodegradation rate of BPS increased in the presence of chloride and ferric ions,while the rate was inhibited by nitrate and phosphate in aqueous solution.

  4. FPGA Flash Memory High Speed Data Acquisition

    Science.gov (United States)

    Gonzalez, April

    2013-01-01

    The purpose of this research is to design and implement a VHDL ONFI Controller module for a Modular Instrumentation System. The goal of the Modular Instrumentation System will be to have a low power device that will store data and send the data at a low speed to a processor. The benefit of such a system will give an advantage over other purchased binary IP due to the capability of allowing NASA to re-use and modify the memory controller module. To accomplish the performance criteria of a low power system, an in house auxiliary board (Flash/ADC board), FPGA development kit, debug board, and modular instrumentation board will be jointly used for the data acquisition. The Flash/ADC board contains four, 1 MSPS, input channel signals and an Open NAND Flash memory module with an analog to digital converter. The ADC, data bits, and control line signals from the board are sent to an Microsemi/Actel FPGA development kit for VHDL programming of the flash memory WRITE, READ, READ STATUS, ERASE, and RESET operation waveforms using Libero software. The debug board will be used for verification of the analog input signal and be able to communicate via serial interface with the module instrumentation. The scope of the new controller module was to find and develop an ONFI controller with the debug board layout designed and completed for manufacture. Successful flash memory operation waveform test routines were completed, simulated, and tested to work on the FPGA board. Through connection of the Flash/ADC board with the FPGA, it was found that the device specifications were not being meet with Vdd reaching half of its voltage. Further testing showed that it was the manufactured Flash/ADC board that contained a misalignment with the ONFI memory module traces. The errors proved to be too great to fix in the time limit set for the project.

  5. Single Particle Difraction at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Bogan, M.; Boutet, S.; Starodub, Dmitri; Decorwin-Martin, Philippe; /SLAC; Chapman, H.; Bajt, S.; Schulz, J.; /DESY; Hajdu, Janos; Seibert, M.M.; Iwan, Bianca; Timneanu, Nicusor; /Uppsala U.; Marchesini, Stefano; /LBL, Berkeley; Barty, Anton; Benner, W.Henry; Frank, Matthias; Hau-Riege, Stefan P.; Woods, Bruce; /LLNL, Livermore; Rohner, Urs; /Tofwerk AG, Thun

    2010-06-11

    Single-pulse coherent diffraction patterns have been collected from randomly injected single particles with a soft X-ray free-electron laser (FEL). The intense focused FEL pulse gives a high-resolution low-noise coherent diffraction pattern of the object before that object turns into a plasma and explodes. A diffraction pattern of a single particle will only be recorded when the particle arrival into the FEL interaction region coincides with FEL pulse arrival and detector integration. The properties of the experimental apparatus coinciding with these three events set the data acquisition rate. For our single particle FLASH diffraction imaging experiments: (1) an aerodynamic lens stack prepared a particle beam that consisted of particles moving at 150-200 m/s positioned randomly in space and time, (2) the 10 fs long FEL pulses were delivered at a fixed rate, and (3) the detector was set to integrate and readout once every two seconds. The effect of these experimental parameters on the rate of data acquisition using randomly injected particles will be discussed. Overall, the ultrashort FEL pulses do not set the limit of the data acquisition, more important is the effective interaction time of the particle crossing the FEL focus, the pulse sequence structure and the detector readout rate. Example diffraction patterns of randomly injected ellipsoidal iron oxide nanoparticles in different orientations are presented. This is the first single particle diffraction data set of identical particles in different orientations collected on a shot-to-shot basis. This data set will be used to test algorithms for recovering 3D structure from single particle diffraction.

  6. Karst flash floods: an example from the Dinaric karst (Croatia

    Directory of Open Access Journals (Sweden)

    O. Bonacci

    2006-01-01

    Full Text Available Flash floods constitute one of the deadliest and costliest natural disasters worldwide. This paper explains the karst flash flood phenomenon, which represents a special kind of flash flood. As the majority of flash floods karst flash floods are caused by intensive short-term precipitation in an area whose surface rarely exceeds a few square kilometres. The characteristics of all flash floods are their short duration, small areal extent, high flood peaks and rapid flows, and heavy loss of life and property. Karst flash floods have specific characteristics due to special conditions for water circulation, which exist in karst terrains. During karst flash floods a sudden rise of groundwater levels occurs, which causes the appearance of numerous, unexpected, abundant and temporary karst springs. This paper presents in detail an example of a karst flash flood in the Marina bay (Dinaric karst region of Croatia, which occurred in December 2004.

  7. A Comparative Study of Reduced-Variables-Based Flash and Conventional Flash

    DEFF Research Database (Denmark)

    Yan, Wei; Stenby, Erling Halfdan; Michelsen, Michael Locht

    2013-01-01

    the advantages of the reduced-variables methods in their recent paper. A fair comparison between the reduced-variables-based flash and the conventional flash is not straightforward because it is difficult to formulate the former as unconstrained minimization problems, and the flash calculation time is also...... related to the implementation quality. With the recent formulations by Nichita and Graciaa (2011), it is possible to code the reduced-variables methods without extensive modifications of Michelsen's conventional flash algorithm. A minimization-based reduced-variables algorithm was coded and compared...... with the conventional minimization-based flash. A test with the use of the SPE 3 example (Kenyon and Behie 1987) showed that the best reduction in time was less than 20% for the extreme situation of 25 components and just one row/column with nonzero BIPs. A better performance can be achieved by a simpler implementation...

  8. Unexpected photolysis of the sunscreen octinoxate in the presence of the sunscreen avobenzone.

    Science.gov (United States)

    Sayre, Robert M; Dowdy, John C; Gerwig, Andre J; Shields, William J; Lloyd, Roger V

    2005-01-01

    A major concern raised about photostability studies of sunscreen products is that the photodegradation of sunscreens does not readily translate into changes in product performance. This study examines the correlation between photochemical degradation of sunscreen agents and changes in protection provided by sunscreen films. Films of a commercial sunscreen product containing avobenzone, oxybenzone and octinoxate were irradiated using a fluorescent UV-A phototherapy lamp with additional UV-B blocking filter. Periodically, during irradiation the transmittances of the films were measured and samples collected for chemical analysis of the sunscreen agents using high-performance liquid chromatography techniques. The results show that UV-induced changes in UV transmittance of sunscreen films correlate with changes in concentration of sunscreen agents. In a parallel experiment, we also irradiated a thin film of the same product in the cavity of an electron spin resonance (ESR) spectrometer. We report the concomitant photolysis of avobenzone and octinoxate that predominates over expected E/Z photoisomerization and that irradiation of a film of this product produced free radicals detected by ESR spectroscopy that persisted even after exposure had ended.

  9. Photo-assisted electrochemical degradation of simulated textile effluent coupled with simultaneous chlorine photolysis.

    Science.gov (United States)

    de Mello Florêncio, Thaíla; de Araújo, Karla Santos; Antonelli, Raissa; de Toledo Fornazari, Ana Luiza; da Cunha, Paula Cordeiro Rodrigues; da Silva Bontempo, Letícia Helena; de Jesus Motheo, Artur; Granato, Ana Claudia; Malpass, Geoffroy Roger Pointer

    2016-10-01

    The influence of chloride ion concentration during the photo-assisted electrochemical degradation of simulated textile effluent, using a commercial Ti/Ru0.3Ti0.7O2 anode, was evaluated. Initially, the effect of applied current and supporting electrolyte concentration on the conversion of chloride ions to form reactive chlorine species in 90 min of experiment was analyzed in order to determine the maximum production of reactive chlorine species. The optimum conditions encountered (1.5 A and 0.3 mol dm(-3) NaCl) were subsequently employed for the degradation of simulated textile effluent. The efficiency of the process was determined through the analysis of chemical oxygen demand (COD), total organic carbon (TOC), of the presence of organochlorine products and phytotoxicity. Photo-assisted electrochemical degradation was more efficient for COD and TOC removal than the electrochemical technique alone. With simultaneous UV irradiation, a reduced quantity of reactive chlorine was produced, indicating that photolysis of the chlorine species led to the formation of hydroxyl radicals. This fact turns a simple electrochemical process into an advanced oxidation process.

  10. [Effect of ionic liquid [bmim][PF6] on the transient photolysis behavior of xanthone].

    Science.gov (United States)

    Fu, Hai-Ying; Cao, Xi-Yan; Xing, Zhao-Guo; Wu, Guo-Zhong

    2013-07-01

    The transient photochemical behavior of xanthone (XAN) in 1-butyl-3-methyl imidazolium hexafluoride phosphate ionic liquid ([bmim][PF6]) or binary mixed solution with acetonitrile (MeCN) was investigated by nano-second laser photolysis techniques. The spectral blue shift of 3XAN* was observed in the neat [bmim][PF6] or IL/MeCN mixture solution compared to MeCN solution. And the yield was also increased. Moreover, the energy transfer rate constant of XAN and naphthalene (NAP) was affected by the concentrations of ionic liquid. The values decreased rapidly with increasing VIL. For example, the values were 1.2 x 10(10) mol x L(-1) x s(-1) in MeCN, and 1.1 x 10(8) mol x L(-1) x s(-1) in [bmim][PF6], respectively. The photo-induced electron transfer between XAN and N,N-dimethylaniline was also investigated by changing the concentrations of [bmim][PF6] in binary solution.

  11. Super Resolution Image Enhancement for a Flash Lidar: Back Projection Method

    Science.gov (United States)

    Bulyshev, Alexander; Hines, Glenn; Vanek, Michael; Amzajerdian, Farzin; Reisse, Robert; Pierrottet, Diego

    2010-01-01

    In this paper a new image processing technique for flash LIDAR data is presented as a potential tool to enable safe and precise spacecraft landings in future robotic or crewed lunar and planetary missions. Flash LIDARs can generate, in real-time, range data that can be interpreted as a 3-dimensional (3-D) image and transformed into a corresponding digital elevation map (DEM). The NASA Autonomous Landing and Hazard Avoidance (ALHAT) project is capitalizing on this new technology by developing, testing and analyzing flash LIDARs to detect hazardous terrain features such as craters, rocks, and slopes during the descent phase of spacecraft landings. Using a flash LIDAR for this application looks very promising, however through theoretical and simulation analysis the ALHAT team has determined that a single frame, or mosaic, of flash LIDAR data may not be sufficient to build a landing site DEM with acceptable spatial resolution, precision, size, or for a mosaic, in time, to meet current system requirements. One way to overcome this potential limitation is by enhancing the flash LIDAR output images. We propose a new super-resolution algorithm applicable to flash LIDAR range data that will create a DEM with sufficient accuracy, precision and size to meet current ALHAT requirements. The performance of our super-resolution algorithm is analyzed by processing data generated during a series of simulation runs by a high fidelity model of a flash LIDAR imaging a high resolution synthetic lunar elevation map. The flash LIDAR model is attached to a simulated spacecraft by a gimbal that points the LIDAR to a target landing site. For each simulation run, a sequence of flash LIDAR frames is recorded and processed as the spacecraft descends toward the landing site. Each run has a different trajectory profile with varying LIDAR look angles of the terrain. We process the output LIDAR frames using our SR algorithm and the results show that the achieved level of accuracy and precision of

  12. General review of flashing jet studies.

    Science.gov (United States)

    Polanco, Geanette; Holdø, Arne Erik; Munday, George

    2010-01-15

    The major concern on the management of superheated liquids, in industrial environments, is the large potential hazards involved in cases of any accidental release. There is a possibility that a violent phase change could take place inside the fluid released generating a flashing jet. This violent phase change might produce catastrophic consequences, such as explosions, fires or toxic exposure, in the installations and in the surroundings. The knowledge and understanding of the mechanisms involved in those releases become an important issue in the prevention of these consequences and the minimization of their impact. This work presents a comprehensive review of information about flashing processes. The review begins with a description of the single phase jet followed by a description of the two-phase flashing jet. The concepts and implications of the thermodynamic and mechanical effects on the behaviour of the jets are considered at the beginning of the review. Following the review is devoted to the classification of the different study approaches used to understand flashing processes in the past, highlighting various critical parameters on the behaviour and the hazard consequences of flashing jets. The review also contains an extensive compilation of experimental, theoretical and numerical data relating to these phenomena, which includes information on the distinct characteristics of the jet, since type of jet, velocity distribution, expansion angle and mass phase change all require individual estimation.

  13. General review of flashing jet studies

    Energy Technology Data Exchange (ETDEWEB)

    Polanco, Geanette, E-mail: gpolanco@usb.ve [Simon Bolivar University, Caracas (Venezuela, Bolivarian Republic of); Holdo, Arne Erik, E-mail: Erik.Holdo@coventry.ac.uk [Narvik University College, Narvik (Norway); Munday, George, E-mail: G.Munday@isaaconsult.co.uk [Coventry University, Coventry (United Kingdom)

    2010-01-15

    The major concern on the management of superheated liquids, in industrial environments, is the large potential hazards involved in cases of any accidental release. There is a possibility that a violent phase change could take place inside the fluid released generating a flashing jet. This violent phase change might produce catastrophic consequences, such as explosions, fires or toxic exposure, in the installations and in the surroundings. The knowledge and understanding of the mechanisms involved in those releases become an important issue in the prevention of these consequences and the minimization of their impact. This work presents a comprehensive review of information about flashing processes. The review begins with a description of the single phase jet followed by a description of the two-phase flashing jet. The concepts and implications of the thermodynamic and mechanical effects on the behaviour of the jets are considered at the beginning of the review. Following the review is devoted to the classification of the different study approaches used to understand flashing processes in the past, highlighting various critical parameters on the behaviour and the hazard consequences of flashing jets. The review also contains an extensive compilation of experimental, theoretical and numerical data relating to these phenomena, which includes information on the distinct characteristics of the jet, since type of jet, velocity distribution, expansion angle and mass phase change all require individual estimation.

  14. Lightning flash multiplicity in eastern Mediterranean thunderstorms

    Science.gov (United States)

    Yair, Y.; Shalev, S.; Erlich, Z.; Agrachov, A.; Katz, E.; Saaroni, H.; Price, C.; Ziv, B.

    2014-02-01

    Cloud-to-ground lightning flashes usually consist of one or several strokes coming in very short temporal succession and close spatial proximity. A commonly used method for converting stroke data into flashes is using the National Lightning Detection Network (NLDN) thresholds of maximum temporal separation of 0.5 s and maximum lateral distance of 10 km radius between successive strokes. In the present study, we tested a location-based algorithm with several spatial and temporal ranges, and analyzed stroke data obtained by the Israel Lightning Location System (ILLS) during one year (1.8.2009-31.7.2010). We computed the multiplicity, the percentage of single stroke flashes and the geographical distribution of average multiplicity values for thunderstorms in the Eastern Mediterranean region. Results show that for the NLDN thresholds, the percentage of single stroke flashes in Israel was 37% and the average multiplicity was 1.7. We reanalyzed the data with a spatial range that equals twice the ILLS location error and shorter times. For the new thresholds of maximum distance of 2.5 km and maximum allowed temporal separation of 0.2 s we find that the mean multiplicity of negative CGs is lowered to 1.4 and find a percentage of 58% of single stroke flashes. A unique severe storm from 30 October 2009 is analyzed and compared with the annual average of 2009/2010, showing that large deviations from the mean values can occur in specific events.

  15. An Evaluation of the FAST-J Photolysis algorithm for predicting nitrogen dioxide photolysis rates under clear and cloudy sky conditions

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, James C.; Chapman, Elaine G.; Fast, Jerome D.; Schmelzer, John R.; Schlusser, James R.; Shetter, Richard E.

    2004-07-04

    The FAST-J model was developed to quickly calculate photolysis rates under both clear and cloudy sky conditions. In this paper, photolysis rates of nitrogen dioxide (NO2) were calculated using FAST-J and compared with measurements taken at two sites in the United States: Phoenix, Arizona, and Houston, Texas. The measurements were derived from either an actinic flux filter radiometer (Phoenix) or a spectroradiometer (Houston). A sun photometer, sited nearby these radiometers, provided irradiances measurements from which aerosol and cloud optical thicknesses were obtained. Aerosol single scattering albedo was not known, but was taken to be either 0.79 or 0.94, representative of either soot-like aerosols or sulfate-like aerosols, respectively. These optical properties served as input to the FAST-J model, which in turn was used to calculate photolysis rates. For both clear and cloudy sky cases, the modeled and measured photolysis rates agree within the uncertainties of the measurements for a single scattering albedo of 0.94. For a single scattering albedo of 0.79, the agreement is again within the uncertainty limits except for the cloudy sky case in Houston.

  16. A Laser Photolysis Study of Triplet Lifetimes and of Triplet–Triplet Annihilation Reactions of Phthalocyanins in DMSO Solutions (Etude des Durées de Vie du Triplet et des Réactions d'Annihilation Triplet–Triplet de Phthalocyanines dans le DMSO par Photolyse Laser)

    OpenAIRE

    Debacker, M. G.; Deleplanque, O.; Van Vlierberge, B.; Sauvage, F. X.

    1988-01-01

    Triplet decay of Mg and Zn phthalocyanins have been studied by laser flash photolysis as a function of concentration. The triplet decay mechanism changes from a near first order in dilute solution to an almost second order in concentrated solutions. This is interpreted in terms of triplet–triplet recombinaison. With the help of a reducing agent, it is shown that the triplet–triplet reaction can lead to charge separation.La décroissance des états excités triplet des phthalocyanines de Mg et de...

  17. SNR efficiency of combined bipolar gradient echoes: Comparison of three-dimensional FLASH, MPRAGE, and multiparameter mapping with VFA-FLASH and MP2RAGE.

    Science.gov (United States)

    Jutras, Jean-David; Wachowicz, Keith; Gilbert, Guillaume; De Zanche, Nicola

    2017-06-01

    High-bandwidth bipolar multiecho gradient echo sequences are increasingly popular in structural brain imaging because of reduced water-fat shifts, lower susceptibility effects, and improved signal-to-noise ratio (SNR) efficiency. In this study, we investigated the performance of three three-dimensional multiecho sequences (MPRAGE, MP2RAGE, and FLASH) with scan times technique with multiecho FLASH (VFA-FLASH). Multiecho sequences were optimized to yield equivalent contrast and improved SNR compared with their single-echo counterparts. Theoretical SNR gains were verified with measurements in a multilayered phantom. Robust image processing pipelines extracted PD, T1 , and T2* maps from MP2RAGE or VFA-FLASH, and the corresponding SNR was measured with varying SENSE accelerations (R = 1-5) and number of echoes (N = 1-12). All sequences were tested on four healthy volunteers. Multiecho sequences achieved SNR gains of 1.3-1.6 over single-echo sequences. MP2RAGE yielded comparable T1 -to-noise ratio to VFA-FLASH, but significantly lower SNR (sampling bandwidths. VFA-FLASH surpasses MP2RAGE in its ability to map three parameters with high SNR and 1-mm isotropic resolution in a clinically relevant scan time (∼8:30 min), whereas MP2RAGE yields lower intersubject variability in T1 . Magn Reson Med 77:2186-2202, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  18. Highly conductive copper nano/microparticles ink via flash light sintering for printed electronics

    Science.gov (United States)

    Joo, Sung-Jun; Hwang, Hyun-Jun; Kim, Hak-Sung

    2014-07-01

    In this study, the size effect of copper particles on the flash light sintering of copper (Cu) ink was investigated using Cu nanoparticles (20-50 nm diameter) and microparticles (2 μm diameter). Also, the mixed Cu nano-/micro-inks were fabricated, and the synergetic effects between the Cu nano-ink and micro-ink on flash light sintering were assessed. The ratio of nanoparticles to microparticles in Cu ink and the several flash light irradiation conditions (irradiation energy density, pulse number, on-time, and off-time) were optimized to obtain high conductivity of Cu films. In order to precisely monitor the milliseconds-long flash light sintering process, in situ monitoring of electrical resistance and temperature changes of Cu films was conducted during the flash light irradiation using a real-time Wheatstone bridge electrical circuit, thermocouple-based circuit, and a high-rate data acquisition system. Also, several microscopic and spectroscopic characterization techniques such as scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy were used to characterize the flash light sintered Cu nano-/micro-films. In addition, the sheet resistance of Cu film was measured using a four-point probe method. This work revealed that the optimal ratio of nanoparticles to microparticles is 50:50 wt%, and the optimally fabricated and flash light sintered Cu nano-/micro-ink films have the lowest resistivity (80 μΩ cm) among nano-ink, micro-ink, or nano-micro mixed films.

  19. Efficient Circuit Configuration for Enhancing Resolution of 8-bit flash Analog to Digital Convertor

    Directory of Open Access Journals (Sweden)

    Gururaj Balikatti

    2012-11-01

    Full Text Available The need constantly exists for converters with higher resolution, faster conversion speeds and lower power dissipation. High speed analog to digital converters (ADCs have been based on flash architecture, because all comparators sample the analog input voltage simultaneously, this ADC is thus inherently fast. Unfortunately flash ADC requires 2N - 1 comparators to convert N bit digital code from an analog sample. This makes flash ADCs unsuitable for high resolution applications. The focus of this paper is on efficient circuit configuration to enhance resolution of available 8-bit flash ADC, while maintaining number of comparators only 256 for 12 bit conversion. This technique optimizes the number of comparator requirements. In this approach, an 8-bit flash ADC partitions the analog input range into 256 quantization cells, separated by 255 boundary points. An 8-bit binary code 00000000 to 11111111 is assigned to each cell. The Microcontroller decides within which cell the input sample lies and assigns a 12-bit binary center code 000000000000 to 111111111111 according to the cell value. The exact 12-bit digital code is obtained by successive approximation technique. In this paper the focus will be on all-around efficient circuit for enhancing resolution of 8-bit Flash ADC. It is shown that by adopting this configuration, we can obtain 12-bit digital data just using 256 comparators. Therefore this technique is best suitable when high speed combined with high resolution is required. An experimental prototype of proposed 12-bit ADC was implemented using Philips P89V51RD2BN Microcontroller. Use of Microcontroller has greatly reduced the hardware requirement and cost. An ADC result of 12-bit prototype is presented. The results show that the ADC exhibits a maximum DNL of 0.52LSB and a maximum INL of 0.55LSB.

  20. Dissolved organic matter photolysis in Canadian arctic thaw ponds

    Science.gov (United States)

    Laurion, Isabelle; Mladenov, Natalie

    2013-09-01

    The abundant thaw lakes and ponds in the circumarctic receive a new pool of organic carbon as permafrost peat soils degrade, which can be exposed to significant irradiance that potentially increases as climate warms and ice cover shortens. Exposure to sunlight is known to accelerate the transformation of dissolved organic matter (DOM) into molecules that can be more readily used by microbes. We sampled the water from two common classes of ponds found in the ice-wedge system of continuous permafrost regions of Canada, polygonal and runnel ponds, and followed the transformation of DOM over 12 days by looking at dissolved organic carbon (DOC) concentration and DOM absorption and fluorescence properties. The results indicate a relatively fast decay of color (3.4 and 1.6% loss d-1 of absorption at 320 nm for the polygonal and runnel pond, respectively) and fluorescence (6.1 and 8.3% loss d-1 of total fluorescent components, respectively) at the pond surface, faster in the case of humic-like components, but insignificant losses of DOC over the observed period. This result indicates that direct DOM mineralization (photochemical production of CO2) is apparently minor in thaw ponds compared to the photochemical transformation of DOM into less chromophoric and likely more labile molecules with a greater potential for microbial mineralization. Therefore, DOM photolysis in arctic thaw ponds can be considered as a catalytic mechanism, accelerating the microbial turnover of mobilized organic matter from thawing permafrost and the production of greenhouse gases, especially in the most shallow ponds. Under a warming climate, this mechanism will intensify as summers lengthen.

  1. Impact of dissolved organic matter on the photolysis of the ionizable antibiotic norfloxacin

    Institute of Scientific and Technical Information of China (English)

    Chen Liang; Huimin Zhao; Minjie Deng; Xie Quan; Shuo Chen; Hua Wang

    2015-01-01

    Norfloxacin (NOR),an ionizable antibiotic frequently used in the aquaculture industry,has aroused public concern due to its persistence,bacterial resistance,and environmental ubiquity.Therefore,we investigated the photolysis of different species of NOR and the impact of a ubiquitous component of natural water-dissolved organic matter (DOM),which has a special photochemical activity and normally acts as a sensitizer or inhibiter in the photolysis of diverse organics; furthermore,scavenging experiments combined with electron paramagnetic resonance (EPR) were performed to evaluate the transformation of NOR in water.The results demonstated that NOR underwent direct photolysis and self-sensitized photolysis via hydroxyl radical (·OH) and singlet oxygen (1O2) based on the scavenging experiments.In addition,DOM was found to influence the photolysis of different NOR species,and its impact was related to the concentration of DOM and type of NOR species.Photolysis of cationic NOR was photosensitized by DOM at low concentration,while zwitterionic and anionic NOR were photoinhibited by DOM,where quenching of ·OH predominated according to EPR experiments,accompanied by possible participation of excited triplet-state NOR and 1O2.Photo-intermediate identification of different NOR species in solutions with/without DOM indicated that NOR underwent different photodegradation pathways including dechlorination,cleavage of the piperazine side chain and photooxidation,and DOM had little impact on the distribution but influenced the concentration evolution of photolysis intermediates.The results implied that for accurate ecological risk assessment of emerging ionizable pollutants,the impact of DOM on the environmental photochemical behavior of all dissociated species should not be ignored.

  2. Impact of dissolved organic matter on the photolysis of the ionizable antibiotic norfloxacin.

    Science.gov (United States)

    Liang, Chen; Zhao, Huimin; Deng, Minjie; Quan, Xie; Chen, Shuo; Wang, Hua

    2015-01-01

    Norfloxacin (NOR), an ionizable antibiotic frequently used in the aquaculture industry, has aroused public concern due to its persistence, bacterial resistance, and environmental ubiquity. Therefore, we investigated the photolysis of different species of NOR and the impact of a ubiquitous component of natural water - dissolved organic matter (DOM), which has a special photochemical activity and normally acts as a sensitizer or inhibiter in the photolysis of diverse organics; furthermore, scavenging experiments combined with electron paramagnetic resonance (EPR) were performed to evaluate the transformation of NOR in water. The results demonstated that NOR underwent direct photolysis and self-sensitized photolysis via hydroxyl radical (OH) and singlet oxygen ((1)O2) based on the scavenging experiments. In addition, DOM was found to influence the photolysis of different NOR species, and its impact was related to the concentration of DOM and type of NOR species. Photolysis of cationic NOR was photosensitized by DOM at low concentration, while zwitterionic and anionic NOR were photoinhibited by DOM, where quenching of OH predominated according to EPR experiments, accompanied by possible participation of excited triplet-state NOR and (1)O2. Photo-intermediate identification of different NOR species in solutions with/without DOM indicated that NOR underwent different photodegradation pathways including dechlorination, cleavage of the piperazine side chain and photooxidation, and DOM had little impact on the distribution but influenced the concentration evolution of photolysis intermediates. The results implied that for accurate ecological risk assessment of emerging ionizable pollutants, the impact of DOM on the environmental photochemical behavior of all dissociated species should not be ignored. Copyright © 2014. Published by Elsevier B.V.

  3. Reduced Comparator Flash ADC for ECG Applications

    Directory of Open Access Journals (Sweden)

    Saravanan. V. A

    2013-03-01

    Full Text Available A CMOS based low power 4-bit Flash Analog to Digital Converter (ADC design with reduced number of comparators than the conventional Flash Analog to Digital Converter and multiplexer based architecture is proposed. For improving the conversion rate, both the analog and digital parts of the ADC are fully modified and the architecture uses only 4 comparators instead of 15 as used in conventional flash ADC, thus saving considerable amount of power. The proposed 4-bit ADC is designed and simulated in TANNER tools with 1.2 V supply voltage using TSpice simulation. The proposed design consumes low power of 2.15mW and operates at a faster rate hence it is suitable for ECG applications.

  4. Mental models of flash floods and landslides.

    Science.gov (United States)

    Wagner, Klaus

    2007-06-01

    Perceptions of flash floods and landslides were analyzed in four communities of the Bavarian Alps using the mental model approach. Thirty-eight qualitative interviews, two telephone surveys with 600 respondents, and two onsite interviews (74/95 respondents) were conducted. Mental models concerning flash floods are much better developed than those for landslides because the key physical processes for flash floods are easier for the general public to recognize and understand. Mental models are influenced by the local conditions. People who have a better knowledge about the hazards are those who use many different sources to inform themselves, express fear about natural hazards, or have previous experience with hazards. Conclusions for how to improve information for the general public are discussed.

  5. Creating Flash advertising from concept to tracking-microsites, video ads and more

    CERN Document Server

    Fincanon, Jason

    2007-01-01

    Create awe-inspiring, mind-blowing Flash ads and microsites that engage consumers and demonstrate their worth to clients. The Hands-On Guide to Creating Flash Advertising delivers the nuts and bolts of the development process from initial design conception to ad completion. You'll learn the best practices for:* Mastering the myriad of ad specs, deadlines, quality and version control issues* Creating ads that balance campaign goals with design constraints* Preparing and building ads with team and QC standards* Using forms and data in ads without file bloat* File optimization techniques for swf

  6. Centrally active nonhormonal hot flash therapies.

    Science.gov (United States)

    Loprinzi, Charles L; Stearns, Vered; Barton, Debra

    2005-12-19

    Given the problems associated with hormonal therapy, and the prominent problem of hot flashes in menopausal women, there is a need for nonhormonal agents to alleviate hot flashes. Several compounds that appear to act on the central nervous system have been investigated. Potential mechanisms for their effects on hot flashes have been described. Bellergal (no longer available on the US market, where it was known as Bellergal-S), a combination preparation sedative that consists of low-dose phenobarbital, ergotamine tartrate, and levorotatory alkaloids of belladonna, is an old agent that was popular approximately 20 years ago; however, there is limited suggestion of efficacy for this agent. Clonidine, an older antihypertensive drug, is another centrally active agent that has been studied. Randomized trials have demonstrated that it clearly works for reducing hot flashes, but the magnitude of efficacy is somewhat limited. Toxicity from this agent limits its utility in the clinic. Methyldopa is another centrally active agent that has been studied but to a more limited degree. It appears to have minimal efficacy and too much toxicity to make it clinically useful. Anecdotal observations from a number of sources suggested that newer antidepressants can alleviate hot flashes. This led to pilot trials of venlafaxine and paroxetine, with results suggesting benefit from both drugs. Subsequently, randomized, placebo-controlled, double-blind clinical trials of venlafaxine, paroxetine, and fluoxetine were conducted. All 3 of these clinical trials demonstrated statistically significant reductions in hot flashes with these newer antidepressants compared with placebo. Pilot trials of citalopram and mirtazapine, 2 other newer antidepressants, have also suggested efficacy. Toxicity evaluations have suggested that these agents are, again, well tolerated by the majority of patients. A recent trial, however, was unable to demonstrate any benefit for fluoxetine or citalopram over a placebo

  7. Foundation Flash CS5 for Designers

    CERN Document Server

    Green, T

    2010-01-01

    Flash is one of the most engaging, innovative, and versatile technologies available - allowing the creation of anything from animated banners and simple cartoons to Rich Internet Applications, interactive videos, and dynamic user interfaces for web sites, kiosks, devices, or DVDs. The possibilities are endless, and now it just got better. Flash CS5 boasts a host of new features, including better support for mobile devices, a whole new animation engine enabling full manipulation of tweens and paths, custom easing, improved inverse kinematics, a revamped timeline, built-in 3D, and much more. Thi

  8. Digital post-calibration of a 5-bit 1.25 GS/s flash ADC

    Institute of Scientific and Technical Information of China (English)

    杨阳; 赵显利; 仲顺安; 李国峰

    2012-01-01

    We report a high-speed flash analog to digital converter (ADC) linearization technique employing the inverse Volterra model and digital post processing.First,a 1.25 GS/s 5-bit flash ADC is designed using a 0.18μm CMOS,and the signal is quantized by a distributed track-and-hold circuit.Second,based on the Volterra series,a proposed digital post-calibration model is introduced.Then,the model is applied to estimate and compensate the nonlinearity of the high-speed flash ADC.Simulation results indicate that the distortion is reduced effectively.Specifically,the ADC achieves gains of 4.83 effective bits for a 117.1 MHz frequency input and 4.74 effective bits for a Nyquist input at 1.25 GS/s.

  9. Flash floods: forecasting and warning

    National Research Council Canada - National Science Library

    Sene, Kevin

    2013-01-01

    ... and levees.The volume discusses the increasing use of meteorological observation and forecasting techniques to extend the lead time available for warning, combined with hydrological models for the river response...

  10. Cancer treatment: dealing with hot flashes and night sweats

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000826.htm Cancer treatment: dealing with hot flashes and night sweats To ... this page, please enable JavaScript. Certain types of cancer treatments can cause hot flashes and night sweats. Hot ...

  11. Flash3D EDL Sensor Technology Advancement Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Scientific Concepts Inc. (ASC) is a small business, which has developed a number of 3D flash LADAR systems. Flash Ladar sensors are 3D video systems that...

  12. 3D Flash LIDAR EDL Resolution Improvement Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Scientific Concepts, Inc. (ASC) is a small business that has developed 3D Flash LIDAR systems for space and terrestrial applications. 3D Flash LIDAR is...

  13. Sunset science. III. Visual adaptation and green flashes.

    Science.gov (United States)

    Young, A T

    2000-12-01

    Photographs of green flashes do not preclude a role for physiological effects in these phenomena. While green flashes are certainly not after-images, there is compelling evidence that adaptation in the visual system strongly affects the perceived color of most sunset green flashes. Furthermore, the retinal image of the setting Sun is usually bright enough to bleach most of the red-sensitive photopigment in a few seconds, making the yellow stage of a sunset flash appear green. Even in air so hazy that no green light reaches the eye, a yellow flash may occur and appear green. Many, but not all, visual observations of sunset green flashes are of this yellow flash. The yellow portion of sunset green flashes helps explain their reported durations, which exceed those expected for the appearance of green light alone.

  14. Effect of colloids on the occurrence, distribution and photolysis of emerging organic contaminants in wastewaters.

    Science.gov (United States)

    Yan, Caixia; Nie, Minghua; Yang, Yi; Zhou, Junliang; Liu, Min; Baalousha, Mohammed; Lead, Jamie R

    2015-12-15

    The effect of colloids on the occurrence, phase distribution and photolysis of twenty-seven emerging organic contaminants (EOCs) was studied in domestic and livestock wastewaters (DW and LW), respectively. Filtered water (colloids was 13.5% and 14.4% in DW and LW. Most of the EOCs exhibited pseudo-first-order degradation kinetics in all water samples. Control experiments using glass and quartz reactors showed that UV light was more effective on the photolysis of most EOCs. The EOCs photolysis in the three fractions of DW and LW could be accelerated or inhibited compared to ultrapure water with the enhancement factor ranging from -0.94 to 7.33. The impact of colloids on the photolysis of EOCs depended on the compound and the source of water. The photolysis of most EOCs in permeates and filtrates was generally accelerated, while inhibited in the retentates, which could be attributed to the relatively high dissolved organic carbon contents in retentates. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Anthracene and pyrene photolysis kinetics in aqueous, organic, and mixed aqueous-organic phases

    Science.gov (United States)

    Grossman, Jarod N.; Stern, Adam P.; Kirich, Makena L.; Kahan, Tara F.

    2016-03-01

    Condensed phases in the atmosphere, such as cloud droplets and aerosols, often contain both water and organic matter (OM). Reactivity can differ significantly between aqueous and organic phases. We have measured photolysis kinetics of the polycyclic aromatic hydrocarbons (PAHs) anthracene and pyrene in several organic solvents and in water, as well as in miscible and phase-separated aqueous-organic mixtures at atmospherically-relevant wavelengths. Photolysis rate constants generally increased with increasing solvent polarity; photolysis of both PAHs was more than ten times faster in water than in octanol. Local polarity had a much greater effect on PAH photolysis kinetics than changes in PAH absorptivity or singlet oxygen concentrations. Photolysis kinetics in homogeneous aqueous-organic mixtures varied monotonically with2 OM volume fraction. Kinetics in immiscible (phase-separated) solutions were more complex, with different dependences on OM content observed in stagnant and turbulent solutions. Our results suggest that OM could greatly affect the photochemical lifetimes of PAHs in atmospheric condensed phases such as aerosols, even if the OM does not itself absorb photons.

  16. Combined Application of UV Photolysis and Ozonation with Biological Aerating Filter in Tertiary Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    Zhaoqian Jing

    2012-01-01

    Full Text Available To enhance the biodegradability of residual organic pollutants in secondary effluent of wastewater treatment plants, UV photolysis and ozonation were used in combination as pretreatment before a biological aerating filter (BAF. The results indicated that UV photolysis could not remove much COD (chemical oxygen demand, and the performance of ozonation was better than the former. With UV photolysis combined with ozonation (UV/O3, COD removal was much higher than the sum of that with UV photolysis and ozonation alone, which indicated that UV photolysis could efficiently promote COD removal during ozonation. This pretreatment also improved molecular weight distribution (MWD and biodegradability greatly. Proportion of organic compounds with molecular weight (MW <3 kDalton was increased from 51.9% to 85.9%. COD removal rates with BAF and O3/BAF were only about 25% and 38%, respectively. When UV/O3 oxidation was combined with BAF, the average COD removal rate reached above 61%, which was about 2.5 times of that with BAF alone. With influent COD ranging from 65 to 84 mg/L, the effluent COD was stably in the scope of 23–31 mg/L. The combination of UV/O3 oxidation with BAF was quite efficient in organic pollutants removal for tertiary wastewater treatment.

  17. Product study of the photolysis of ketene and ethyl ethynyl ether at 193.3 nm.

    Science.gov (United States)

    Fockenberg, Christopher

    2005-08-18

    The product distributions of the excimer laser photolysis of ketene (CH2CO) and ethyl ethynyl ether (C2H5OCCH) at lambda = 193.3 nm (ArF) were studied using a time-of-flight mass spectrometer (TOFMS) as an analytical tool. Ketene was photolyzed in bath gases consisting of mixtures of He and H2/D2 at various mixing ratios at constant total pressures of 4 Torr and temperature of about 300 K. Singlet methylene (1CH2) produced in the photolysis of ketene was almost instantaneously converted either to triplet methylene (3CH2) or to methyl radicals in collisions with He and H2 or D2. By extrapolating the methyl and methylene signals to zero time after photolysis, initial concentrations of these radicals were obtained. Analyzing the initial 3CH2 and CH3 concentrations as functions of hydrogen-to-helium ratios as well as simulating the observed traces of reactant and product species resulted in 1CH2 + CO (66 +/- 8)%, as the main product channel of the ketene photolysis with smaller contributions from HCCO + H (17 +/- 7)% and 3CH2 + CO (6 +/- 9)%. Hydrogen atoms, acetylene, ethylene, ethyl, and ketenyl radicals, and small amounts of ketene were observed as primary products of the ethyl ethynyl ether photolysis. Quantification of C2H2, C2H4, C2H5, and CH2CO product leads to a HCCO yield of (91 +/- 14)%.

  18. Mainostoimiston Flash-tuotantoprosessin kehittäminen

    OpenAIRE

    Heinonen, Toni

    2012-01-01

    Tämän opinnäytetyön tarkoituksena oli kehittää mainostoimiston Flash-tuotantoprosessia. Mainostoimiston Flash-tuotanto on pääosin display-mainonnan eli bannereiden sekä Flashmainoskampanjasivustojen luontia. Lisäksi tarkoituksena oli tutkia mahdollisuutta soveltaa ohjelmistokehityksessä toimiviksi havaittujen ketterien prosessimallien soveltamista mainostoimiston Flash-tuotantoprosessiin. Työ aloitettiin kuvaamalla mainostoimiston nykyinen Flash-tuotantoprosessi tarkoitukseen ...

  19. Ultrafast-Contactless Flash Sintering using Plasma Electrodes

    OpenAIRE

    Theo Saunders; Salvatore Grasso; Reece, Michael J.

    2016-01-01

    This paper presents a novel derivative of flash sintering, in which contactless flash sintering (CFS) is achieved using plasma electrodes. In this setup, electrical contact with the sample to be sintered is made by two arc plasma electrodes, one on either side, allowing current to pass through the sample. This opens up the possibility of continuous throughput flash sintering. Preheating, a usual precondition for flash sintering, is provided by the arc electrodes which heat the sample to 1400 ...

  20. Flash Thermography to Evaluate Porosity in Carbon Fiber Reinforced Polymer (CFRPs

    Directory of Open Access Journals (Sweden)

    Carosena Meola

    2014-02-01

    Full Text Available It is a fact that the presence of porosity in composites has detrimental effects on their mechanical properties. Then, due to the high probability of void formation during manufacturing processes, it is necessary to have the availability of non-destructive evaluation techniques, which may be able to discover the presence and the distribution of porosity in the final parts. In recent years, flash thermography has emerged as the most valuable method, but it is still not adequately enclosed in the industrial enterprise. The main reason of this is the lack of sufficient quantitative data for a full validation of such a technique. The intention of the present work is to supply an overview on the current state-of-the-art regarding the use of flash thermography to evaluate the porosity percentage in fiber reinforced composite materials and to present the latest results, which are gathered by the authors, on porous carbon fiber reinforced polymer laminates. To this end, several coupons of two different stacking sequences and including a different amount of porosity are fabricated and inspected with both non-destructive and destructive testing techniques. Data coming from non-destructive testing with either flash thermography or ultrasonics are plotted against the porosity percentage, which was previously estimated with the volumetric method. The new obtained results are a witness to the efficacy of flash thermography. Some key points that need further consideration are also highlighted.

  1. Mathematical modeling of the flash converting process

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, H.Y.; Perez-Tello, M.; Riihilahti, K.M. [Utah Univ., Salt Lake City, UT (United States)

    1996-12-31

    An axisymmetric mathematical model for the Kennecott-Outokumpu flash converting process for converting solid copper matte to copper is presented. The model is an adaptation of the comprehensive mathematical model formerly developed at the University of Utah for the flash smelting of copper concentrates. The model incorporates the transport of momentum, heat, mass, and reaction kinetics between gas and particles in a particle-laden turbulent gas jet. The standard k-{epsilon} model is used to describe gas-phase turbulence in an Eulerian framework. The particle-phase is treated from a Lagrangian viewpoint which is coupled to the gas-phase via the source terms in the Eulerian gas-phase governing equations. Matte particles were represented as Cu{sub 2}S yFeS, and assumed to undergo homogeneous oxidation to Cu{sub 2}O, Fe{sub 3}O{sub 4}, and SO{sub 2}. A reaction kinetics mechanism involving both external mass transfer of oxygen gas to the particle surface and diffusion of oxygen through the porous oxide layer is proposed to estimate the particle oxidation rate Predictions of the mathematical model were compared with the experimental data collected in a bench-scale flash converting facility. Good agreement between the model predictions and the measurements was obtained. The model was used to study the effect of different gas-injection configurations on the overall fluid dynamics in a commercial size flash converting shaft. (author)

  2. In Situ Flash Pyrolysis of Straw

    DEFF Research Database (Denmark)

    Bech, Niels

    In-Situ Flash Pyrolysis of Straw Ph.D. dissertation by Niels Bech Submitted: April 2007. Supervisors: Professor Kim Dam-Johansen, Associate Professor Peter Arendt Jensen Erfaringerne med forbrænding af halm opnået gennem et årti har vist, at en proces der kan koncentrere energien på marken, fjerne...

  3. High-fidelity flash lidar model development

    Science.gov (United States)

    Hines, Glenn D.; Pierrottet, Diego F.; Amzajerdian, Farzin

    2014-06-01

    NASA's Autonomous Landing and Hazard Avoidance Technologies (ALHAT) project is currently developing the critical technologies to safely and precisely navigate and land crew, cargo and robotic spacecraft vehicles on and around planetary bodies. One key element of this project is a high-fidelity Flash Lidar sensor that can generate three-dimensional (3-D) images of the planetary surface. These images are processed with hazard detection and avoidance and hazard relative navigation algorithms, and then are subsequently used by the Guidance, Navigation and Control subsystem to generate an optimal navigation solution. A complex, high-fidelity model of the Flash Lidar was developed in order to evaluate the performance of the sensor and its interaction with the interfacing ALHAT components on vehicles with different configurations and under different flight trajectories. The model contains a parameterized, general approach to Flash Lidar detection and reflects physical attributes such as range and electronic noise sources, and laser pulse temporal and spatial profiles. It also provides the realistic interaction of the laser pulse with terrain features that include varying albedo, boulders, craters slopes and shadows. This paper gives a description of the Flash Lidar model and presents results from the Lidar operating under different scenarios.

  4. Flash-Aware Page Replacement Algorithm

    Directory of Open Access Journals (Sweden)

    Guangxia Xu

    2014-01-01

    Full Text Available Due to the limited main memory resource of consumer electronics equipped with NAND flash memory as storage device, an efficient page replacement algorithm called FAPRA is proposed for NAND flash memory in the light of its inherent characteristics. FAPRA introduces an efficient victim page selection scheme taking into account the benefit-to-cost ratio for evicting each victim page candidate and the combined recency and frequency value, as well as the erase count of the block to which each page belongs. Since the dirty victim page often contains clean data that exist in both the main memory and the NAND flash memory based storage device, FAPRA only writes the dirty data within the victim page back to the NAND flash memory based storage device in order to reduce the redundant write operations. We conduct a series of trace-driven simulations and experimental results show that our proposed FAPRA algorithm outperforms the state-of-the-art algorithms in terms of page hit ratio, the number of write operations, runtime, and the degree of wear leveling.

  5. RELATIONSHIP BETWEEN FLASH POINTS OF SOME BINARY ...

    African Journals Online (AJOL)

    B. S. Chandravanshi

    and BS-150 in the formulation of engine oils, the recent mineral oils were chosen for study. On the other .... blend. Upon analysis of the data due to Figure 1 (b) it can be shown that the flash point of every. SN-150: .... complex compositions.

  6. Incoherent-light-flash annealing of phosphorus-implanted silicon

    Science.gov (United States)

    Correra, L.; Pedulli, L.

    1980-07-01

    Incoherent light pulses emitted from a xenon flash lamp were used to anneal radiation damage in (100) silicon implanted with 2×1015 31P+/cm2 at 100 keV. Electrical carrier concentration has been determined by means of differential sheet resistivity and Hall effect together with the anodic oxidation stripping technique; the surface photovoltage technique has been used to evaluate bulk lifetime and Rutherford backscattering and transmission electron microscopy for analysis of radiation damage. Damage recovery appears to take place via a solid phase epitaxial process. Electrical activity and carrier mobility values of samples annealed by incoherent light are similar to those obtained by laser, electron beam, and furnace annealing. The bulk lifetime of minority carriers is not degraded.

  7. Analysis of N-nitrosodiethylamine by ion chromatography coupled with UV photolysis pretreatment

    Directory of Open Access Journals (Sweden)

    Xueli Li

    2016-04-01

    Full Text Available Nitrosamines such as N-nitrosodiethylamine (NDEA are commonly detected by spectrophotometry after photolysis and Griess reaction (PG in food industries for lower cost. Results of this research indicate that NDEA decays rapidly under UV irradiation, and concentrations of the generated NO2− and NO3− ions vary with photolysis conditions. Thus, the measurement of the PG method may be inconsistent because it is based on the amount of photoproduced NO2−. In addition, more errors may be present in the PG method since NO3− cannot be measured colorimetrically using Griess reagent. In this work, the sum of the concentrations of photoproduced NO2− and NO3− was found to be equivalent to the initial NDEA before photolysis, and a photolysis–ion chromatography method was validated, which may serve as a feasible and accurate method to determine nitrosamines.

  8. Formation of hydroxyl radicals from photolysis of secondary organic aerosol material

    Directory of Open Access Journals (Sweden)

    K. M. Badali

    2015-02-01

    Full Text Available This paper demonstrates that OH radicals are formed by photolysis of secondary organic aerosol (SOA material formed by terpene ozonolysis. The SOA aerosol is collected on filters, dissolved in water containing a radical trap (benzoic acid, and then exposed to ultraviolet light in a photochemical reactor. The OH formation rates, which are similar for both α-pinene and limonene SOA, are measured from the formation rate of p-hydroxybenzoic acid as measured using offline HPLC analysis. To evaluate whether the OH is formed by photolysis of H2O2 or organic hydroperoxides (ROOH, the peroxide content of the SOA was measured using the horseradish peroxidase-dichlorofluorescein (HRP-DCF assay, which was calibrated using H2O2. The OH formation rates from SOA are five times faster than from the photolysis of H2O2 solutions whose concentrations correspond to the peroxide content of the SOA solutions assuming that the HRP-DCF signal arises from H2O2 alone. The higher rates of OH formation from SOA are likely due to ROOH photolysis. This result is substantiated by photolysis experiments conducted with t-butyl hydroperoxide and cumene hydroperoxide which produce over three times more OH than photolysis of equivalent concentrations of H2O2. Relative to the peroxide level in the SOA, the quantum yield for OH generation from α-pinene SOA is 0.8 ± 0.4. This is the first demonstration of an efficient photolytic source of OH in SOA, one that may affect both cloudwater and aerosol chemistry.

  9. HCO Cross Sections and Radical Yields From the Photolysis of Saturated Aldehydes

    Science.gov (United States)

    Flad, J. E.; Brown, S. S.; Burkholder, J. B.; Ravishankara, A. R.

    2005-12-01

    Aldehydes are a major component of oxygenated volatile organic compounds (OVOC) in the atmosphere. They are removed from the atmosphere primarily by reaction with OH or by photodissociation from ultraviolet (radicals. Determination of the radical yields from aldehyde photolysis as a function of temperature, pressure and wavelength has important implications for the HOx budget, particularly in the upper troposphere. Photolysis of formaldehyde and acetaldehyde has been studied extensively in the laboratory, although current parameterizations for radical yields are based in part on studies that have used indirect methods. A sensitive and direct method of measuring these radical yields is therefore of substantial interest. A new instrument has been developed to measure formyl (HCO) radical yields from the photodissociation of aldehydes. A pulsed, tunable ultraviolet laser is used to photolyze the aldehyde between 290 and 350 nm, and a second tunable laser is used to detect the HCO radicals using cavity ring-down spectroscopy on the A-X system (613 - 617 nm). The photolysis and probe lasers copropagate along the axis of the ring-down cell to maximize the overlap of the two laser beams for sensitive HCO detection. The absorption cross section of HCO has been determined by measuring the HCO product from the reaction of atomic chlorine with formaldehyde relative to the NO 3 product from the reaction of atomic chlorine with chlorine nitrate. Atomic chlorine was generated by photolysis of Cl 2 at 335 nm. The HCO quantum yield from the photolysis of acetaldehyde and formaldehyde and its dependence on photolysis wavelength, temperature, and pressure is being studied.

  10. Photolysis of RDX and nitroglycerin in the context of military training ranges.

    Science.gov (United States)

    Bordeleau, Geneviève; Martel, Richard; Ampleman, Guy; Thiboutot, Sonia

    2013-09-01

    Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and nitroglycerin (NG) are two energetic materials commonly found in the environment on military training ranges. They are deposited on the ground in the form of solid particles, which can then dissolve in infiltration water or in surface water bodies. The objective of this study was to evaluate whether photolysis by sunlight can significantly contribute to the natural attenuation of RDX and NG (as solid particles or dissolved in surface water) at mid-northern latitudes, where training ranges of Canada and many European countries are located. Experiments conducted at 46.9°N show that both compounds are degraded by sunlight when dissolved in water, with half-lives between 1 and 120d, depending on the compound and time of year. Numerical models may be useful in predicting such photolysis rates, but the models should take into account current ozone levels, as older radiation datasets, collected before the ozone depletion observed since the late 1970s, underestimate the RDX/NG photolysis rate. For solid RDX or NG-bearing particles, photolysis is slower (half-lives of 2-4months), but the degradation rate is still rapid enough to make this process significant in a natural attenuation context. However, photolysis of NG embedded within solid propellant particles cannot proceed to completion, due to the stable nitrocellulose matrix of the propellant. Nonetheless, photolysis clearly constitutes an important attenuation mechanism that should be considered in conceptual models and included in numerical modeling efforts. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Kinetics and mechanism of photolysis and TiO2 photocatalysis of triclosan.

    Science.gov (United States)

    Son, Hyun-Seok; Ko, Gwangpyo; Zoh, Kyung-Duk

    2009-07-30

    The degradations of triclosan (5-chloro-2-(2,4-dichlorophenoxy)-phenol), a potent broad-spectrum antimicrobial agent, were compared in TiO2-only in the dark condition, photolysis, and TiO2 photocatalysis with a UV-A lamp. TiO2 photocatalysis more effectively degraded and mineralized triclosan compared to TiO2-only and photolysis conditions. While triclosan removed only 30% by TiO2-only condition within 20 min, the triclosan degradation in photolysis and photocatalysis at the same time was 75 and 82%, respectively, and TOC removal was significantly higher in photocatalysis than in photolysis. The data of kinetics showed that triclosan adsorption onto TiO2 was fitted to Langmuir isotherm, and TiO2 photocatalysis was fitted to Langmuir-Hinshelwood model (b=27.99 mM(-1), K(triclosan)=9.49 mM(-1)). The neutral range of pH was favorable to photocatalysis due to the charge effect between TiO2 and triclosan. The addition of 2-propanol, a radical scavenger, significantly reduced the degradation of triclosan both in photolysis and photocatalysis. Dioxin-type intermediates such as dibenzo-dichloro-p-dioxin (DCDD), dibenzo-p-dioxin were produced in photolysis with and without 2-propanol, and also in photocatalysis with 2-propanol, but these intermediates were not detected in photocatalysis without 2-propanol. This result indicates that the photocatalytic degradation of triclosan is mainly achieved by radicals, and these radicals can further degrade dioxin-type intermediates once they are produced in photocatalysis.

  12. Initial electric field changes of lightning flashes in two thunderstorms

    Science.gov (United States)

    Chapman, Ryan; Marshall, Thomas; Karunarathne, Sumedhe; Stolzenburg, Maribeth

    2017-04-01

    The beginning of all 75 lightning flashes in two small thunderstorms was investigated using an array of electric field change (E-change) meters and an array of VHF sensors with the goal of determining if an initial E-change (IEC) preceded the initial breakdown (IB) pulses in each flash. IECs were found at the beginning of all 62 flashes in Storm 1 and all 13 flashes in Storm 2. Hence, it is concluded that an IEC is a fundamental part of most or all lightning initiations and that an IEC is needed prior to the first IB pulse in a flash. IEC durations averaged 0.23 ms for cloud-to-ground (CG) flashes (range 0.08-0.54 ms) and averaged 2.7 ms for normal intracloud (IC) flashes (range 0.04-9.8 ms). IEC point dipole moments averaged 26 C m for CG flashes (range 4-86 C m) and averaged -140 C m for normal IC flashes (range -8 to -650 C m). IEC current moments averaged 120 kA m for CG flashes (range 41-410 kA m) and averaged -91 kA m for normal IC flashes (range -2 to -630 kA m). E-change data support the suggestion that weak narrow bipolar event type events initiate some lightning flashes, but 41 of the 75 flashes had no detectable initiating pulse > 0.04 V m-1 range normalized to 100 km. Two flashes had two IECs; the second IEC of each flash initiated a new lightning channel that propagated in a new direction and at a higher altitude than the original development after the first IEC.

  13. Room temperature FePt nanoparticles formation kinetics by laser solution photolysis

    CSIR Research Space (South Africa)

    Nkosi, S

    2012-04-01

    Full Text Available Formation Kinetics by Laser solution photolysis S. Nkosi1, B.W. Mwakikunga2, E. Sideras-Haddad1 1University of the Witwatersrand 2 DST/NCNSM, Pretoria The 4th International Conference on Nanoscience and Nanotechnology 1 – 4 April 2012, University... emission during photolysis, � the produced either positive or negative metallic ions (liquid form). Theoretical consideration transabsreflLASER IIII ++= Energy conservation (Kirchoff’s law) lossestransferheat dt dNVH dt dTV V NCII ptransabs __+∆∆+∆== Slide...

  14. Photolysis and OH-Initiated oxidation of glycolaldehyde under atmospheric conditions.

    Science.gov (United States)

    Magneron, I; Mellouki, A; Le Bras, G; Moortgat, G K; Horowitz, A; Wirtz, K

    2005-05-26

    The photolysis and OH-initiated oxidation of glycolaldehyde (HOCH(2)CHO), which are relevant atmospheric processes, have been investigated under different conditions using complementary methods in three different laboratories. The UV absorption cross sections of glycolaldehyde determined in two of the laboratories are in excellent agreement. The photolysis of glycolaldehyde in air has been investigated in a quartz cell with sunlamps and in the EUPHORE chamber irradiated by sunlight. The mean photolysis rate measured under solar radiation was (1.1 +/- 0.3) x 10(-5) s(-1) corresponding to a mean effective photolysis quantum yield of (1.3 +/- 0.3). The major products detected were HCHO and CO, whereas CH(3)OH was also observed with an initial yield around 10%. Evidence for OH production was found in both experiments using either OH scavenger or OH tracer species. Photolysis of glycolaldehyde was used as the OH source to measure the reaction rate constants of OH with a series of dienes by the relative method and to identify and quantify the oxidation products of the OH-initiated oxidation of 2-propanol. The different experiments suggest that OH is produced by the primary channel: HOCH(2)CHO + hnu --> OH + CH(2)CHO (1). The rate constant of the OH reaction with glycolaldehyde has been measured at 298 K using the relative method: k(glyc) = (1.2 +/- 0.3) x 10(-11) cm(3) molecule(-1) s(-1). The product study of the OH-initiated oxidation of glycolaldehyde in air has been performed using both a FEP bag and the EUPHORE chamber. HCHO was observed to be the major product with a primary yield of around 65%. Glyoxal (CHOCHO) was also observed in EUPHORE with a primary yield of (22 +/- 6)%. This yield corresponds to the branching ratio ( approximately 20%) of the H-atom abstraction channel from the CH(2) group in the OH + HOCH(2)CHO reaction, the major channel ( approximately 80%) being the H-atom abstraction from the carbonyl group. The data obtained in this work, especially the

  15. Experimental Research on Flash Boiling Spray of Dimethyl Ether

    Institute of Scientific and Technical Information of China (English)

    Peng Zhang

    2014-01-01

    The high-speed digital imaging technique is applied to observe the developing process of flash boiling spray of dimethyl ether at low ambient pressure, and the effects of nozzle opening pressure and nozzle hole diameter on the spray shape, spray tip penetration and spray angle during the injection are investigated. The experimental results show that the time when the vortex ring structure of flash boiling spray forms and its developing process are determined by the combined action of the bubble growth and breakup in the spray and the air drag on the leading end of spray;with the enhancement of nozzle opening pressure, the spray tip penetration increases and the spray angle decreases. The influence of nozzle hole diameter on the spray tip penetration is relatively complicated, the spray tip penetration is longer with a smaller nozzle hole diameter at the early stage of injection, while the situation is just opposite at the later stage of injection. This paper establishes that the variation of spray angle is consistent with that of nozzle hole diameter.

  16. Experimental research on flash boiling spray of dimethyl ether

    Science.gov (United States)

    Zhang, Peng

    2014-12-01

    The high-speed digital imaging technique is applied to observe the developing process of flash boiling spray of dimethyl ether at low ambient pressure, and the effects of nozzle opening pressure and nozzle hole diameter on the spray shape, spray tip penetration and spray angle during the injection are investigated. The experimental results show that the time when the vortex ring structure of flash boiling spray forms and its developing process are determined by the combined action of the bubble growth and breakup in the spray and the air drag on the leading end of spray; with the enhancement of nozzle opening pressure, the spray tip penetration increases and the spray angle decreases. The influence of nozzle hole diameter on the spray tip penetration is relatively complicated, the spray tip penetration is longer with a smaller nozzle hole diameter at the early stage of injection, while the situation is just opposite at the later stage of injection. This paper establishes that the variation of spray angle is consistent with that of nozzle hole diameter.

  17. FLASH: A finite element computer code for variably saturated flow

    Energy Technology Data Exchange (ETDEWEB)

    Baca, R.G.; Magnuson, S.O.

    1992-05-01

    A numerical model was developed for use in performance assessment studies at the INEL. The numerical model, referred to as the FLASH computer code, is designed to simulate two-dimensional fluid flow in fractured-porous media. The code is specifically designed to model variably saturated flow in an arid site vadose zone and saturated flow in an unconfined aquifer. In addition, the code also has the capability to simulate heat conduction in the vadose zone. This report presents the following: description of the conceptual frame-work and mathematical theory; derivations of the finite element techniques and algorithms; computational examples that illustrate the capability of the code; and input instructions for the general use of the code. The FLASH computer code is aimed at providing environmental scientists at the INEL with a predictive tool for the subsurface water pathway. This numerical model is expected to be widely used in performance assessments for: (1) the Remedial Investigation/Feasibility Study process and (2) compliance studies required by the US Department of Energy Order 5820.2A.

  18. Matter Flashed at Ultra Speed

    Science.gov (United States)

    2007-06-01

    "REM observations of GRB060418 and GRB060607A: the onset of the afterglow and the initial fireball Lorentz factor determination", by E. Molinari, S. D. Vergani, D. Malesani, S. Covino, et al. The paper is available at http://dx.doi.org/10.1051/0004-6361:20077388 (A&A, 469, L13-L16, 2007). The REM team is formed by G. Chincarini, E. Molinari, F.M. Zerbi, L.A. Antonelli, S. Covino, P. Conconi, L. Nicastro, E. Palazzi, M. Stefanon, V. Testa, G. Tosti, F. Vitali, A. Monfardini, F. D'Alessio, P. D'Avanzo, D. Fugazza, G. Malaspina, S. Piranomonte, S.D. Vergani, P.A. Ward, S. Campana, P. Goldoni, D. Guetta, D. Malesani, N. Masetti, E.J.A. Meurs, L. Norci, E. Pian, A. Fernandez-Soto, L. Stella, G. Tagliaferri, G. Ihle, L. Gonzalez, A. Pizarro, P. Sinclair, and J. Valenzuela. Notes Gamma-ray bursts (GRBs) are short flashes of energetic gamma-rays lasting from less than a second to several minutes. They release a tremendous quantity of energy in this short time making them the most powerful events since the Big Bang. They come in two different flavours, long and short ones. Over the past few years, international efforts have convincingly shown that long gamma-ray bursts are linked with the ultimate explosion of massive stars (hypernovae; see e.g. ESO PR 16/03) while the short ones most likely originate from the violent collision of neutron stars and/or black holes (see e.g. ESO PR 26/05 and 32/05). Irrespective of the original source of the GRB energy, the injection of so much energy into a confined volume will cause a fireball to form. Gamma-ray photons have nearly a million times more energy than the 'visual' photons the eye can see. Strictly speaking, the Lorentz factor is the ratio between the total and rest-mass energy of the fireball. REM (Rapid Eye Mount) is a small (60 cm mirror diameter) rapid reaction automatic telescope dedicated to monitor the prompt afterglow of Gamma Ray Burst events. It is located at the ESO La Silla Observatory in Chile. For more information, see

  19. Next High Performance and Low Power Flash Memory Package Structure

    Institute of Scientific and Technical Information of China (English)

    Jung-Hoon Lee

    2007-01-01

    In general, SAND flash memory has advantages in low power consumption, storage capacity, and fast erase/write performance in contrast to NOR flash. But, main drawback of the SAND flash memory is the slow access time for random read operations. Therefore, we proposed the new SAND flash memory package for overcoming this major drawback. We present a high performance and low power SAND flash memory system with a dual cache memory. The proposed SAND flash package consists of two parts, i.e., an SAND flash memory module, and a dual cache module. The new SAND flash memory system can achieve dramatically higher performance and lower power consumption compared with any conventional NAND-type flash memory module. Our results show that the proposed system can reduce about 78% of write operations into the flash memory cell and about 70% of read operations from the flash memory cell by using only additional 3KB cache space. This value represents high potential to achieve low power consumption and high performance gain.

  20. Miniature ambulatory skin conductance monitor and algorithm for investigating hot flash events.

    Science.gov (United States)

    Bahr, Dennis E; Webster, John G; Grady, Deborah; Kronenberg, Fredi; Creasman, Jennifer; Macer, Judy; Shults, Mark; Tyler, Mitchell; Zhou, Xin

    2014-02-01

    A skin conductance monitoring system was developed and shown to reliably acquire and record hot flash events in both supervised laboratory and unsupervised ambulatory conditions. The 7.2 × 3.8 × 1.2 cm(3) monitor consists of a disposable adhesive patch supporting two hydrogel electrodes and a reusable, miniaturized, enclosed electronic circuit board that snaps onto the electrodes. The monitor measures and records the skin conductance for seven days without external wires or telemetry and has an event marker that the subject can press whenever a hot flash is experienced. The accuracy of the system was demonstrated by comparing the number of hot flashes detected by algorithms developed during this research with the number identified by experts in hot flash studies. Three methods of detecting hot flash events were evaluated, but only two were fully developed. The two that were developed were an artificial neural network and a matched filter technique with multiple kernels implemented as a sliding form of the Pearson product-moment correlation coefficient. Both algorithms were trained on a 'development' cohort of 17 women and then validated using a second similar 'validation' cohort of 20. All subjects were between the ages of 40 and 60 and self-reported ten or more hot flashes per day over a three day period. The matched filter was the most accurate with a mean sensitivity of 0.92 and a mean specificity of 0.90 using the data from the development cohort and a mean sensitivity of 0.92 and a mean specificity of 0.87 using the data from the validation cohort. The matched filter was the method implemented in our processing software.

  1. Problems for determining the thermal conductivity of TBCs by laser-flash method

    Directory of Open Access Journals (Sweden)

    O. Altun

    2008-10-01

    Full Text Available Purpose: The purpose of this paper was to investigate the parameters which effect the results of determining the thermal conductivity of thermal barrier coatings (TBCs by laser-flash method.Design/methodology/approach: The air plasma-spray (APS technique was used to deposition of two- and three-layered samples. Two-layered samples were composed of metal substrate (321 stainless steel, and ceramic top coat (8YSZ. Three-layered samples were composed of metal substrate (321 stainless steel, bond coat (NiCrAlY and top coat (8YSZ. Thermal diffusivity of each layer have been measured in the temperature range from room temperature (RT to 900ºC by laser-flash method. The thermal conductivity was calculated with respect to density, specific heat and diffusivity of the materials.Findings: Obtained results show that the specific heat, density and thicknesses of metal substrate, bond coat and top coat play important role in the thermal conductivity measurement.Research limitations/implications: To obtain the correct results in laser-flash technique thickness, density, and cp of the materials are needed to be measured accurately and surface smoothness of samples should be provided sensitively. Errors in these parameters cause high deviations in measurements.Practical implications: It has been aimed offer an insight into the experimental determination of thermal conductivity of layered TBC system which are used in high technologic applications.Originality/value: Laser-flash method is the most widely used experimental technique to determine the thermal conductivity of APS TBCs at high temperatures. The research contributes to better understanding and recognition the importance of sample preparation in laser-flash method.

  2. Flash light sintered copper precursor/nanoparticle pattern with high electrical conductivity and low porosity for printed electronics

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Wan-Ho; Hwang, Hyun-Jun [Department of Mechanical Convergence Engineering, Hanyang University, 17 Haendang-Dong, Seongdong-Gu, Seoul 133-791 (Korea, Republic of); Kim, Hak-Sung, E-mail: kima@hanyang.ac.kr [Department of Mechanical Convergence Engineering, Hanyang University, 17 Haendang-Dong, Seongdong-Gu, Seoul 133-791 (Korea, Republic of); Institute of Nano Science and Technology, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2015-04-01

    In this work, the hybrid copper inks with precursor and nanoparticles were fabricated and sintered via flash light irradiation to achieve highly conductive electrode pattern with low porosity. The hybrid copper ink was made of copper nanoparticles and various copper precursors (e.g., copper(II) chloride, copper(II) nitrate trihydrate, copper(II) sulfate pentahydrate and copper(II) trifluoroacetylacetonate). The printed hybrid copper inks were sintered at room temperature and under ambient conditions using an in-house flash light sintering system. The effects of copper precursor weight fraction and the flash light irradiation conditions (light energy and pulse duration) were investigated. Surfaces of the sintered hybrid copper patterns were analyzed using a scanning electron microscope. Also, spectroscopic characterization techniques such as Fourier transform infrared spectroscopy and X-ray diffraction were used to investigate the crystal phases of the flash light sintered copper precursors. High conductivity hybrid copper patterns (27.3 μΩ cm), which is comparable to the resistivity of bulk copper (1.68 μΩ cm) were obtained through flash light sintering at room temperature and under ambient conditions. - Highlights: • The hybrid copper inks with precursor and nanoparticles were fabricated. • The hybrid copper ink was sintered via flash light irradiation. • The resistivity of sintered hybrid copper ink was 27.3 μΩ cm. • Highly conductive copper film with low porosity could be achieved.

  3. Different behavior of nitrenes and carbenes on photolysis and thermolysis: formation of azirine, ylidic cumulene, and cyclic ketenimine and the rearrangement of 6-phenanthridylcarbene to 9-phenanthrylnitrene.

    Science.gov (United States)

    Kvaskoff, David; Bednarek, Pawel; George, Lisa; Pankajakshan, Sreekumar; Wentrup, Curt

    2005-09-30

    Flash vacuum thermolysis (FVT) of 9-azidophenanthrene 8, 6-(5-tetrazolyl)phenanthridine 18, and [1,2,3]triazolo[1,5-f]phenanthridine 19 yields 9-cyanofluorene 12 as the principal product and 4-cyanofluorene as a minor product. In all cases, when the product is condensed at or below 77 K, the seven-membered ring ketenimine 24 is detectable by IR spectroscopy (1932 cm(-1)) up to 200 K. Photolysis of Ar matrix isolated 8 at lambda = 308 or 313 nm generates at first the azirine 26, rapidly followed by the ylidic cumulene 27. The latter reverts to azirine 26 at lambda > 405 nm, and the azirine reverts to the ylidic cumulene at 313 nm. Nitrene 9 is observed by ESR spectroscopy following FVT of either azide 8, tetrazole 18, or triazole 19 with Ar matrix isolation of the products. Nitrene 9 and carbene 21 are observed by ESR spectroscopy in the Ar matrix photolyses of azide 8 and triazole 19, respectively.

  4. Electrical Safety and Arc Flash Protections

    Energy Technology Data Exchange (ETDEWEB)

    R. Camp

    2008-03-04

    Over the past four years, the Electrical Safety Program at PPPL has evolved in addressing changing regulatory requirements and lessons learned from accident events, particularly in regards to arc flash hazards and implementing NFPA 70E requirements. This presentation will discuss PPPL's approaches to the areas of electrical hazards evaluation, both shock and arc flash; engineered solutions for hazards mitigation such as remote racking of medium voltage breakers, operational changes for hazards avoidance, targeted personnel training and hazard appropriate personal protective equipment. Practical solutions for nominal voltage identification and zero voltage checks for lockout/tagout will also be covered. Finally, we will review the value of a comprehensive electrical drawing program, employee attitudes expressed as a personal safety work ethic, integrated safety management, and sustained management support for continuous safety improvement.

  5. Direct flash steam geothermal power plant assessment

    Science.gov (United States)

    Alt, T. E.

    1982-01-01

    The objective was to analyze the capacity and availability factors of an operating direct flash geothermal power plant. System and component specifications, operating procedures, maintenance history, malfunctions, and outage rate are discussed. The plant studied was the 75 MW(e) geothermal power plant at Cerro Prieto, Mexico, for the years 1973 to 1979. To describe and assess the plant, the project staff reviewed documents, visited the plant, and met with staff of the operating utility. The high reliability and availability of the plant was documented and actions responsible for the good performance were identified and reported. The results are useful as guidance to US utilities considering use of hot water geothermal resources for power generation through a direct flash conversion cycle.

  6. Neural latencies do not explain the auditory and audio-visual flash-lag effect.

    Science.gov (United States)

    Arrighi, Roberto; Alais, David; Burr, David

    2005-11-01

    A brief flash presented physically aligned with a moving stimulus is perceived to lag behind, a well studied phenomenon termed the Flash-Lag Effect (FLE). It has been recently shown that the FLE also occurs in audition, as well as cross-modally between vision and audition. The present study has two goals: to investigate the acoustic and cross-modal FLE using a random motion technique; and to investigate whether neural latencies may account for the FLE in general. The random motion technique revealed a strong cross-modal FLE for visual motion stimuli and auditory probes, but not for the other conditions. Visual and auditory latencies for stimulus appearance and for motion were measured with three techniques: integration, temporal alignment and reaction times. All three techniques showed that a brief static acoustic stimulus is perceived more rapidly than a brief static visual stimulus, while a sound source in motion is perceived more slowly than a comparable visual stimulus. While the results of these three techniques agreed closely with each other, they were exactly opposite that required to account for the FLE by neural latencies. We conclude that neural latencies do not, in general, explain the flash-lag effect. Rather, our data suggest that neural integration times are more important.

  7. CDOM Sources and Photobleaching Control Quantum Yields for Oceanic DMS Photolysis

    KAUST Repository

    Galí, Martí

    2016-11-14

    Photolysis is a major removal pathway for the biogenic gas dimethylsulfide (DMS) in the surface ocean. Here we tested the hypothesis that apparent quantum yields (AQY) for DMS photolysis varied according to the quantity and quality of its photosensitizers, chiefly chromophoric dissolved organic matter (CDOM) and nitrate. AQY compiled from the literature and unpublished studies ranged across 3 orders of magnitude at the 330 nm reference wavelength. The smallest AQY(330) were observed in coastal waters receiving major riverine inputs of terrestrial CDOM (0.06-0.5 m3 (mol quanta)-1). In open-ocean waters, AQY(330) generally ranged between 1 and 10 m3 (mol quanta)-1. The largest AQY(330), up to 34 m3 (mol quanta)-1), were seen in the Southern Ocean potentially associated with upwelling. Despite the large AQY variability, daily photolysis rate constants at the sea surface spanned a smaller range (0.04-3.7 d-1), mainly because of the inverse relationship between CDOM absorption and AQY. Comparison of AQY(330) with CDOM spectral signatures suggests there is an interplay between CDOM origin (terrestrial versus marine) and photobleaching that controls variations in AQYs, with a secondary role for nitrate. Our results can be used for regional or large-scale assessment of DMS photolysis rates in future studies.

  8. The Influence of Photolysis Rate Constants in Ozone Production for the Paso del Norte Region

    Science.gov (United States)

    Becerra, Fernando; Fitzgerald, Rosa

    2012-03-01

    In this research work we are focusing on understanding the relationship between photolysis rates and the photochemical ozone changes observed in the Paso del Norte region. The city of El Paso, Texas together with Ciudad Juarez, Mexico, forms the largest contiguous bi-national metropolitan area. This region suffers year-round ozone pollution events, and a better understanding is needed to mitigate them. Previous studies have found that ambient ozone concentrations tend to be higher on weekends rather than on weekdays, this phenomenon being referred to, as the ``weekend effect.'' If the ozone standard is exceeded more frequently on weekends, then this phenomenon must be considered in the design of ozone control strategies. In this work we investigate some of the most representative weekend ozone episodes at El Paso, TX, during the years 2009, 2010 and 2011 using the ozone photolysis rates. In this research the TUV radiative-transfer model is used to calculate the local photolysis rates and a UV MFRSR instrument is used to obtain experimental parameters. Seasonal variations and the weekday-weekend effect is studied. The results of this research will help to understand the underlying behavior of the photolysis rate constants when different atmospheric conditions are present.

  9. Derivatization and photolysis of a photoaffinity reagent for probing protein and cell surface interactions

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, H.; Harris, H.W. Jr.

    1986-05-01

    The synthesis of the novel, heterobifunctional, cleavable, photoactivable crosslinking reagent, N-(4-(p-azido-m-(/sup 125/I) iodophenylazo)benzoyl)-3-aminopropyl-N'-oxysulfosuccinimide has been described by Denny and Blobel. This reagent is desirable because after photolysis and azo bond cleavage the /sup 125/I is transferred from the reagent to the crosslinked molecule. The authors demonstrate that using the reported synthesis 99% of the desired reagent is destroyed during the chloramine-T iodination step. They report a synthesis revision which produces high yields of the uniodinated (U) reagent. The derivatized reagent may be used in its iodinated (I) or U forms. To study the U reagent, a horseradish peroxidase (HRP) molecule is derivatized with nine reagent molecules. The derivatized HRP has 70% of its original enzymatic activity. After photolysis, 14% of this activity is retained and SDS-PAGE electrophoresis shows a crosslinked complex of HRP molecules. After endocytosis by cells, photolysis attaches the soluble derivatized HRP to membranes allowing them to be traced in the electron microscope. To study the I reagent, an amino-dextran (MW 73-400) molecule is derivatized with three U reagent molecules. The U reagent molecules are then iodinated by the chloramine-T method. With photolysis and cleavage, the /sup 125/I labeled reagent on dextran transfers its label to bovine serum albumin or ovalbumin. The authors conclude this reagent is a versatile probe for study of protein or cell surface topography.

  10. Conformer of the peroxynitrite ion formed under photolysis of crystalline alkali nitrates – cis or trans?

    Science.gov (United States)

    Pak, V. Kh; Anan’ev, V. A.; Dyagileva, E. P.; Lyrshchikov, S. Yu; Miklin, M. B.; Rezvova, M. A.

    2017-01-01

    The optical and infrared reflectance spectra of the crystalline powders prepared by co-crystallization of caesium nitrate, nitrite, and peroxynitrite from alkali solution have been studied. We find that the trans conformer forms under photolysis of crystalline pure caesium nitrate. Under its dissolution the trans conformer transforms to the cis conformer.

  11. CHBr3 (bromoform): Revised UV Absorption Spectrum and Atmospheric Photolysis Rates

    Science.gov (United States)

    Burkholder, J. B.; Papanastasiou, D.; McKeen, S. A.

    2013-12-01

    CHBr3 (bromoform) is a short-lived atmospheric trace compound primarily of natural origin that is a source of reactive bromine in both the troposphere and stratosphere. Estimating the impact of CHBr3 on the environment and its transport to the stratosphere requires a thorough understanding of its atmospheric loss processes, which are primarily UV photolysis and reaction with the OH radical. In this presentation, new measurements of the UV absorption spectrum of CHBr3 will be presented. Spectra were measured at wavelengths between 300 and 345 nm at temperatures between 260 and 330 K using cavity ring-down spectroscopy. The present results will be compared with currently recommended values for use in atmospheric modeling taken from Moortgat et al. [The tropospheric chemistry of ozone in the polar regions, edited by H. Niki and K. H. Becker, Springer-Verlag Berlin Heidelberg, 1993]. The discrepancies and impact on CHBr3 photolysis lifetime will be discussed. A parameterization of the CHBr3 UV spectrum for use in atmospheric models will be presented and local photolysis rate calculations used to highlight the impact of the revised cross section data on local lifetimes and the relative importance of photolysis loss versus reaction with the OH radical. The results from the present study will contribute to a better understanding (and accuracy) of estimates of stratospheric ozone loss due to very short-lived brominated substances.

  12. Degradation mechanisms of geosmin and 2-MIB during UV photolysis and UV/chlorine reactions.

    Science.gov (United States)

    Kim, Tae-Kyoung; Moon, Bo-Ram; Kim, Taeyeon; Kim, Moon-Kyung; Zoh, Kyung-Duk

    2016-11-01

    We conducted chlorination, UV photolysis, and UV/chlorin reactions to investigate the intermediate formation and degradation mechanisms of geosmin and 2-methylisoborneol (2-MIB) in water. Chlorination hardly removed geosmin and 2-MIB, while the UV/chlorine reaction at 254 nm completely removed geosmin and 2-MIB within 40 min and 1 h, respectively, with lesser removals of both compounds during UV photolysis. The kinetics during both UV photolysis and UV/chlorine reactions followed a pseudo first-order reaction. Chloroform was found as a chlorinated intermediate during the UV/chlorine reaction of both geosmin and 2-MIB. The pH affected both the degradation and chloroform production during the UV/chlorine reaction. The open ring and dehydration intermediates identified during UV/chlorine reactions were 1,4-dimethyl-adamantane, and 1,3-dimethyl-adamantane from geosmin, 2-methylenebornane, and 2-methyl-2-bornene from 2-MIB, respectively. Additionally, 2-methyl-3-pentanol, 2,4-dimethyl-1-heptene, 4-methyl-2-heptanone, and 1,1-dichloro-2,4-dimethyl-1-heptane were newly identified intermediates from UV/chlorine reactions of both geosmin and 2-MIB. These intermediates were degraded as the reaction progressed. We proposed possible degradation pathways during the UV photolysis and UV/chlorine reactions of both compounds using the identified intermediates.

  13. Photolysis of tembotrione and its main by-products under extreme artificial conditions:

    Energy Technology Data Exchange (ETDEWEB)

    Calvayrac, Christophe; Bontemps, Nataly [Laboratoire de Chimie des Biomolécules et de l' Environnement (LCBE, EA 4215), Université de Perpignan Via Domitia (UPVD), 52 avenue Paul Alduy, 66860 Perpignan (France); Nouga-Bissoue, Achille [Ecole Nationale Supérieure de l' Enseignement Technique (ENSET), Université de Douala, BP 2701 Douala (Cameroon); Romdhane, Sana; Coste, Camille-Michel [Laboratoire de Chimie des Biomolécules et de l' Environnement (LCBE, EA 4215), Université de Perpignan Via Domitia (UPVD), 52 avenue Paul Alduy, 66860 Perpignan (France); Cooper, Jean-Francois, E-mail: cooper@univ-perp.fr [Laboratoire de Chimie des Biomolécules et de l' Environnement (LCBE, EA 4215), Université de Perpignan Via Domitia (UPVD), 52 avenue Paul Alduy, 66860 Perpignan (France)

    2013-05-01

    The photolytic behaviour of tembotrione, a new chemical herbicide intended for foliar application in corn, was investigated under unnatural and extreme photochemical exposure in aqueous solutions in the laboratory. It appeared that degradation was dependent on pH and occurred more rapidly under acidic and neutral conditions, leading predominantly to the formation of a xanthenedione type compound by intramolecular cyclisation with loss of HCl. Trace amounts of benzoic acid by-products appeared also during UV-C irradiation (λ = 254 nm) of the parent compound. Results were comparable to those obtained with sulcotrione, another β-triketone herbicide. These extreme irradiation conditions clearly accelerated the phototransformation of sulcotrione vs. simulated sunlight irradiation. Furthermore, the photolysis of the degradation by-products, resulting from either photolysis, hydrolysis or biotic pathways of the two active ingredients, was also carried out. The benzoic acid by-products appeared more stable to photolysis than their parent molecules. Xanthenedione derivatives were degraded more rapidly with several differences depending on the pH value. - Highlights: • Tembotrione and sulcotrione water photolysis appeared enhanced under unnatural and extreme conditions. • Triketones were easily photodegraded under acidic and neutral conditions. • Xanthenedione derivatives were the predominant by-products. • Phototransformation of xanthenedione derivatives was pH-dependent. • Benzoic acid derivatives can be relatively stable.

  14. Continuous flow photolysis of aryl azides: Preparation of 3H-azepinones.

    Science.gov (United States)

    Bou-Hamdan, Farhan R; Lévesque, François; O'Brien, Alexander G; Seeberger, Peter H

    2011-01-01

    Photolysis of aryl azides to give nitrenes, and their subsequent rearrangement in the presence of water to give 3H-azepinones, is performed in continuous flow in a photoreactor constructed of fluorinated ethylene polymer (FEP) tubing. Fine tuning of the reaction conditions using the flow reactor allowed minimization of secondary photochemical reactions.

  15. Continuous flow photolysis of aryl azides: Preparation of 3H-azepinones

    Directory of Open Access Journals (Sweden)

    Farhan R. Bou-Hamdan

    2011-08-01

    Full Text Available Photolysis of aryl azides to give nitrenes, and their subsequent rearrangement in the presence of water to give 3H-azepinones, is performed in continuous flow in a photoreactor constructed of fluorinated ethylene polymer (FEP tubing. Fine tuning of the reaction conditions using the flow reactor allowed minimization of secondary photochemical reactions.

  16. Natural solar photolysis of total organic chlorine, bromine and iodine in water.

    Science.gov (United States)

    Abusallout, Ibrahim; Hua, Guanghui

    2016-04-01

    Municipal wastewater has been increasingly used to augment drinking water supplies due to the growing water scarcity. Wastewater-derived disinfection byproducts (DBPs) may negatively affect the aquatic ecosystems and human health of downstream communities during water reuse. The objective of this research was to determine the degradation kinetics of total organic chlorine (TOCl), bromine (TOBr) and iodine (TOI) in water by natural sunlight irradiation. Outdoor solar photolysis experiments were performed to investigate photolytic degradation of the total organic halogen (TOX) formed by fulvic acid and real water and wastewater samples. The results showed that TOX degradation by sunlight irradiation followed the first-order kinetics with half-lives in the range of 2.6-10.7 h for different TOX compounds produced by fulvic acid. The TOX degradation rates were generally in the order of TOI > TOBr ≅ TOCl(NH2Cl) > TOCl(Cl2). High molecular weight TOX was more susceptible to solar photolysis than corresponding low molecular weight halogenated compounds. The nitrate and sulfite induced indirect TOX photolysis rates were less than 50% of the direct photolysis rates under the conditions of this study. Fulvic acid and turbidity in water reduced TOX photodegradation. These results contribute to a better understanding of the fate of chlorinated, brominated and iodinated DBPs in surface waters.

  17. A Unique Equation to Estimate Flash Points of Selected Pure Liquids Application to the Correction of Probably Erroneous Flash Point Values

    Science.gov (United States)

    Catoire, Laurent; Naudet, Valérie

    2004-12-01

    A simple empirical equation is presented for the estimation of closed-cup flash points for pure organic liquids. Data needed for the estimation of a flash point (FP) are the normal boiling point (Teb), the standard enthalpy of vaporization at 298.15 K [ΔvapH°(298.15 K)] of the compound, and the number of carbon atoms (n) in the molecule. The bounds for this equation are: -100⩽FP(°C)⩽+200; 250⩽Teb(K)⩽650; 20⩽Δvap H°(298.15 K)/(kJ mol-1)⩽110; 1⩽n⩽21. Compared to other methods (empirical equations, structural group contribution methods, and neural network quantitative structure-property relationships), this simple equation is shown to predict accurately the flash points for a variety of compounds, whatever their chemical groups (monofunctional compounds and polyfunctional compounds) and whatever their structure (linear, branched, cyclic). The same equation is shown to be valid for hydrocarbons, organic nitrogen compounds, organic oxygen compounds, organic sulfur compounds, organic halogen compounds, and organic silicone compounds. It seems that the flash points of organic deuterium compounds, organic tin compounds, organic nickel compounds, organic phosphorus compounds, organic boron compounds, and organic germanium compounds can also be predicted accurately by this equation. A mean absolute deviation of about 3 °C, a standard deviation of about 2 °C, and a maximum absolute deviation of 10 °C are obtained when predictions are compared to experimental data for more than 600 compounds. For all these compounds, the absolute deviation is equal or lower than the reproductibility expected at a 95% confidence level for closed-cup flash point measurement. This estimation technique has its limitations concerning the polyhalogenated compounds for which the equation should be used with caution. The mean absolute deviation and maximum absolute deviation observed and the fact that the equation provides unbiaised predictions lead to the conclusion that

  18. How to give a science flash talk

    DEFF Research Database (Denmark)

    Veldhuis, Djuke

    2015-01-01

    Whether you are applying for funding, telling a family member about your research or engaging the public, your success will depend on how well you communicate. Persuading people that your research should be prioritised and funded relies on being a solid negotiator and developing political nous; b......; but these skills are also rooted in communication. One way to do this is by challenging yourself to summarise your research in a short, sharp, three-minute elevator pitch, or ‘flash talk’....

  19. Flash CS3 The Missing Manual

    CERN Document Server

    Grover, Chris

    2008-01-01

    Flash CS3, the latest version of the premier tool for creating web animations and interactive web sites, can be intimidating to learn. This entertaining reference tutorial provides a reader-friendly animation primer and a guided tour of all the program's tools and capabilities. Beginners will learn to use the software in no time, and experienced users will quickly take their skills to the next level.

  20. Advances in flash flood monitoring using UAVs

    Science.gov (United States)

    Perks, Matthew; Russell, Andrew; Large, Andrew

    2016-04-01

    UAVs have the potential to capture information about the earth's surface in dangerous and previously inaccessible locations. Through image acquisition of flash flood events and subsequent object-based analysis, highly dynamic and oft-immeasurable hydraulic phenomenon may be quantified at previously unattainable spatial and temporal resolutions. The potential for this approach to provide valuable information about the hydraulic conditions present during dynamic, high-energy flash floods has until now not been explored. In this paper we adopt a novel approach, utilising the Kande-Lucas-Tomasi (KLT) algorithm to track features present on the water surface which are related to the free-surface velocity. Following the successful tracking of features, a method analogous to the vector correction method has enabled accurate geometric rectification of velocity vectors. Uncertainties associated with the rectification process induced by unsteady camera movements are subsequently explored. Geo-registration errors are relatively stable and occur as a result of persistent residual distortion effects following image correction. The apparent ground movement of immobile control points between measurement intervals ranges from 0.05 - 0.13m. The application of this approach to assess the hydraulic conditions present in Alyth Burn, Scotland during a 1:200 year flash flood resulted in the generation of an average 4.2 measurements/m2 at a rate of 508 measurements/s. Analysis of these vectors provide a rare insight into the complexity of channel-overbank interactions during flash floods. The uncertainty attached to the calculated velocities is relatively low with a spatial average across the area of ± 0.15m/s. Little difference is observed in the uncertainty attached to out-of-bank velocities (± 0.15m/s), and within-channel velocities (± 0.16m/s), illustrating the consistency of the approach.

  1. Membuat Game Kuis Menggunakan Macromedia Flash 8

    OpenAIRE

    Lumban Gaol, Cindi N

    2016-01-01

    In the final project , the author makes an application quiz games . This application is a medium of learning that helps students to study for a quiz pep contained in this application relate to the lessons in school . Methods and design a quiz game designed by using software Macromedia Flash 8 as the programming language , script editor program , and is also used to design this application . This study was made aiming to broaden how to create a quiz game simple one. Word Keys : Mac...

  2. Magnesia-Chrome Refractories for Flash Furnace

    Institute of Scientific and Technical Information of China (English)

    LI Yong; CHEN Kaixian; LU Xinghua; LIU Jianlong; SUN Jialin; HONG Yanruo

    2002-01-01

    The rapid development of our country's heavy nonferrous metallurgical technology and the revolution in new type of heavynon-ferrous metallurgical furnace have imposed more critical demand on the refractory materials ,i. e. high quality and long service life. This paper presents the domestic status of the refractories for flash furnace , briefly describes the wear of the refractory used , and it is considered that the domestic in refractories for flashfurnace can be surely realized.

  3. A Comparative Study of Reduced Variables Based Flash and Conventional Flash

    DEFF Research Database (Denmark)

    Michelsen, Michael Locht; Yan, Wei; Stenby, Erling Halfdan

    Speeding up flash calculation is a central issue in compositional reservoir simulations since phase equilibrium calculation is the most time-consuming part in those simulations. The reduced variables methods, or the reduction methods, reformulate the original phase equilibrium problem with a smal......Speeding up flash calculation is a central issue in compositional reservoir simulations since phase equilibrium calculation is the most time-consuming part in those simulations. The reduced variables methods, or the reduction methods, reformulate the original phase equilibrium problem....... Most of the studies in the last decade suggest that the reduced variables methods are much more efficient than the conventional flash method. However, Haugen and Beckner questioned the advantages of the reduced variables methods in their recent paper (SPE 141399). A fair comparison between the reduced...... variables based flash and the conventional flash is not straightforward since the former is difficult to be formulated as unconstrained minimization and involves more complicated composition derivatives. With the recent formulations by Nichita and Graciaa (2010), it is possible to code the reduced variables...

  4. Extreme flash floods in Barcelona County

    Directory of Open Access Journals (Sweden)

    A. Barrera

    2005-01-01

    Full Text Available In this paper the catastrophic and extraordinary floods occurring in Barcelona County (Catalonia, NE Spain are studied, in order to characterise the temporal evolution of extreme flash floods in that area and their main features. These events usually cause economical losses and major problems for undertaking daily activity in Barcelona city. This kind of floods is a very common feature in the North-east of Spain and they are recorded every year in some point of Catalonia. This contribution also shows the frequency of those events, within the framework of all the floods that have occurred in Barcelona since the 14th century, but also describes the flooded area, urban evolution, impacts and the weather conditions for any of most severe events. The evolution of flood occurrence shows the existence of oscillations in the earlier and later modern age periods that can be attributed to climatic variability, evolution of the perception threshold and changes in vulnerability. A great increase of vulnerability can be assumed for the period 1850-1900. The analysis of the time evolution for the Barcelona rainfall series (1854-2000 shows that no trend exists, although, due to the changes in urban planning, flash-floods impact has changed over this time. The number of catastrophic flash floods has diminished, although the extraordinary ones have increased.

  5. Numerical simulation analysis of Guixi copper flash smelting furnace

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A numerical simulation analysis for reactions of chalcopyrite and pyrite particles coupled with momentum, heat and mass transfer between the particle and gas in a flash smelting furnace is presented. In the simulation, the equations governing the gas flow are solved numerically by Eular method. The particle phase is introduced into the gas flow by the particle-source-in-cell technique (PSIC). Predictions including the fluid flow field, temperature field, concentration field of gas phase and the tracks of particles have been obtained by the numerical simulation. The visualized results show that the reaction of sulfide particles is almost completed in the upper zone of the shaft within 1.5 m far from the central jet distributor (CJD) type concentrate burner. The simulation results are in good agreement with data obtained from a series of experiments and tests in the plant and the error is less than 2%.

  6. Warm dense matter and Thomson scattering at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Faeustlin, Roland Rainer

    2010-05-15

    X-ray free electron lasers are powerful tools to investigate moderately to strongly correlated solid density low temperature plasmas, named warm dense matter. These plasmas are of most interest for astrophysics and laser plasma interaction, particularly inertial confinement fusion. This work utilizes the ultrashort soft x-ray pulse duration and high brilliance of the free electron laser in Hamburg, FLASH, to generate warm dense matter and to study its ultrafast processes. The techniques applied are absorption measurement, emission spectroscopy and Thomson scattering. Radiative hydrodynamics and Thomson scattering simulations are used to investigate the impact of temperature and density gradients in the sample and to fit the experimental data. The measurements result in a comprehensive picture of soft x-ray matter interaction related to warm dense matter and yield insight into ultrafast equilibration and relaxation mechanisms, in particular impact ionization and radiative recombination. (orig.)

  7. Flash Profile for rapid descriptive analysis in sensory characterization of passion fruit juice

    Directory of Open Access Journals (Sweden)

    Flávia Daiana Montanuci

    2015-07-01

    Full Text Available The Flash Profile is a descriptive analysis method derived from Free-Choice Profile, in which each taster chooses and uses his/her own words to evaluate the product while comparing several attributes. Four passion fruit juices were analyzed, two juices were produced with concentrated juice, one with pulp and one with reconstituted juice; all juices had different levels of sugar, some had gum and dyes. This study aimed to evaluate the physicochemical properties (color, titratable acidity and solid content as well as sensory analysis like Flash profile and affective test. In physicochemical characterization and in Flash Profile, the juice A (pulp had higher solid content and consistence, the juice B (concentrated juice was the least acidic and presented the lowest value of soluble solids and presented strong aroma and flavor of passion-fruit, the juice C (reconstituted juice was pale yellow and showed artificial flavor and the juice D (concentrated juice was the most acidic, consistent with the natural flavor. In the acceptance test, all the juices scored 5-6, indicating that panelists tasters neither liked nor disliked. Flash Profile proved to be an easy and rapid technique showing a good correlation between panelists and the attributes and confirmed the results of physicochemical characterization.

  8. Flash memories economic principles of performance, cost and reliability optimization

    CERN Document Server

    Richter, Detlev

    2014-01-01

    The subject of this book is to introduce a model-based quantitative performance indicator methodology applicable for performance, cost and reliability optimization of non-volatile memories. The complex example of flash memories is used to introduce and apply the methodology. It has been developed by the author based on an industrial 2-bit to 4-bit per cell flash development project. For the first time, design and cost aspects of 3D integration of flash memory are treated in this book. Cell, array, performance and reliability effects of flash memories are introduced and analyzed. Key performance parameters are derived to handle the flash complexity. A performance and array memory model is developed and a set of performance indicators characterizing architecture, cost and durability is defined.   Flash memories are selected to apply the Performance Indicator Methodology to quantify design and technology innovation. A graphical representation based on trend lines is introduced to support a requirement based pr...

  9. Modeling on Flash Flood Disaster Induced by Bed Load

    Institute of Scientific and Technical Information of China (English)

    CAO Shuyou; LIU Xingnian; HUANG Er; YANG Keiun

    2008-01-01

    Flash floods result from a complex interaction among hydro-meteorological, hydrologi-cal, and hydraulic processes across various spatial and temporal scales. Sichuan Province suffers flash floods frequently owing to mountain weather and topography. A flash flood and gravel bed load transport are two key relative problems in mountain river engineering. Bed materials are often encountered in alternate scouring and deposition in mountain fluvial processes during a flash flood.In this circumstance, CRS-1 bed load numerical model jointly with scale physical model is em-ployed to predict water level and gravel bed scour and deposition for design of flood control dykes and flash flood disaster mitigation. A case study on the mechanism of a flash flood disaster in-duced by bed load transport for a hydropower station in Sichuan Province is conducted. Finally,suggestions to protect the hydropower station are proposed.

  10. Onset conditions for flash sintering of UO2

    Science.gov (United States)

    Raftery, Alicia M.; Pereira da Silva, João Gustavo; Byler, Darrin D.; Andersson, David A.; Uberuaga, Blas P.; Stanek, Christopher R.; McClellan, Kenneth J.

    2017-09-01

    In this work, flash sintering was demonstrated on stoichiometric and non-stoichiometric uranium dioxide pellets at temperatures ranging from room temperature (26 °C) up to 600 °C . The onset conditions for flash sintering were determined for three stoichiometries (UO2.00, UO2.08, and UO2.16) and analyzed against an established thermal runaway model. The presence of excess oxygen was found to enhance the flash sintering onset behavior of uranium dioxide, lowering the field required to flash and shortening the time required for a flash to occur. The results from this study highlight the effect of stoichiometry on the flash sintering behavior of uranium dioxide and will serve as the foundation for future studies on this material.

  11. Flash flow pyrolysis: mimicking flash vacuum pyrolysis in a high-temperature/high-pressure liquid-phase microreactor environment.

    Science.gov (United States)

    Cantillo, David; Sheibani, Hassan; Kappe, C Oliver

    2012-03-02

    Flash vacuum pyrolysis (FVP) is a gas-phase continuous-flow technique where a substrate is sublimed through a hot quartz tube under high vacuum at temperatures of 400-1100 °C. Thermal activation occurs mainly by molecule-wall collisions with contact times in the region of milliseconds. As a preparative method, FVP is used mainly to induce intramolecular high-temperature transformations leading to products that cannot easily be obtained by other methods. It is demonstrated herein that liquid-phase high-temperature/high-pressure (high-T/p) microreactor conditions (160-350 °C, 90-180 bar) employing near- or supercritical fluids as reaction media can mimic the results obtained using preparative gas-phase FVP protocols. The high-T/p liquid-phase "flash flow pyrolysis" (FFP) technique was applied to the thermolysis of Meldrum's acid derivatives, pyrrole-2,3-diones, and pyrrole-2-carboxylic esters, producing the expected target heterocycles in high yields with residence times between 10 s and 10 min. The exact control over flow rate (and thus residence time) using the liquid-phase FFP method allows a tuning of reaction selectivities not easily achievable using FVP. Since the solution-phase FFP method does not require the substrate to be volatile any more--a major limitation in classical FVP--the transformations become readily scalable, allowing higher productivities and space-time yields compared with gas-phase protocols. Differential scanning calorimetry measurements and extensive DFT calculations provided essential information on pyrolysis energy barriers and the involved reaction mechanisms. A correlation between computed activation energies and experimental gas-phase FVP (molecule-wall collisions) and liquid-phase FFP (molecule-molecule collisions) pyrolysis temperatures was derived.

  12. Role of UV photolysis in accelerating the biodegradation of 2,4,6-TCP.

    Science.gov (United States)

    Wang, Wenbing; Kirumba, George; Zhang, Yongming; Wu, Yanqing; Rittmann, Bruce E

    2015-09-18

    2,4,6-TCP, a kind of chlorinated aromatic and aliphatic compound, is difficult to be biodegraded by ordinary microorganisms. UV photolysis and biodegradation of 2,4,6-TCP by Bacillus amyloliquefaciens intimate coupling is a potential means to accelerate its biotransformation. The initial steps of 2,4,6-TCP biodegradation involve mono-oxygenation reactions that have molecular oxygen and an intracellular electron carrier as cosubstrates. It was demonstrated that B. amyloliquefaciens has the 2,4,6-TCP monooxygenase gene tcpA which could encode 2,4,6-TCP monooxygenase (TCP-MO). TCP-MO would catalytically decompose 2,4,6-TCP into 2,6-DCHQ. We employed an internal loop photolytic biofilm reactor for 2,4,6-TCP degradation. Sequentially coupled photolysis and biodegradation experimental results suggested that 2,4,6-TCP removal rate in P + B (TCP(UV) + phenol) protocol was higher by 77 and 103 % when compared to B (TCP + phenol) and B (TCP-only) protocols respectively. The corresponding loss rate coefficient (k) values were 0.069, 0.039, 0.034 mg/L·min(-1) respectively. This is because UV photolysis converted 2,4,6-TCP into its intermediates: 2,4-dichlorophenol (2,4-DCP), 4-monochlorophenol (4-MCP), phenol, 2,6-dichloro-p-hydroquinone (2,6-DCHQ), with all displaying less inhibition to bacterial action. In addition, phenol was the crucial UV-photolysis product from 2,4,6-TCP, its catabolic oxidation generating internal electron carriers that may accelerate the initial steps of 2,4,6-TCP biodegradation. Intimately coupled photolysis and biodegradation experimental results suggested that 2,4,6-TCP removal rate in P&B (TCP + phenol) protocol was higher by 166 and 681 % when compared to P&B (TCP-only) and P + B protocols respectively. The corresponding loss rate coefficient (k) values were 0.539, 0.203, 0.069 mg/L·min(-1) respectively. It provided sufficient evidence to demonstrate that intimately coupled photolysis and biodegradation accelerated 2,4,6-TCP

  13. Multi-channel analyzer controlled by applet and flash

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Both java applet and flash were applied to emulate virtual panel of multi-channel pulse height analyzer (MCA), and Microsoft IE browser was used to control MCA through internet to measure the γ-ray energy spectrum of 137Cs. It Was shown that most of the work completed by applet can be done by flash too, and with flash, more beautiful panel of the remote controlled instruments can be easily designed.

  14. Multi—channel analyzer controlled by applet and flash

    Institute of Scientific and Technical Information of China (English)

    HUANGWen-Da

    2002-01-01

    Both java applet and flash were applied to emulate virtual panel of multi-channel pulse height analyzer(MCA),and Microsoft IE browser was used to control MCA through internet to measure the γ-ray energy spectrum of 137Cs.It was shown that most of the work completed by applet can be done by flash too,and with flash,more beautiful panel of the remote controlled instruments can be easily designed.

  15. The echo-enabled harmonic generation options for FLASH II

    CERN Document Server

    Deng, Haixiao; Faatz, Bart

    2011-01-01

    FLASH II is an upgrade to the existing free electron laser (FEL) FLASH. The echo-enabled harmonic generation (EEHG) scheme is proposed to be a potential seeding option of FLASH II. In this paper, the possibility of EEHG operation of FLASH II is investigated for the first time. With a combination of existing numerical codes, i.e. a laser-beam interaction code in an undulator (LBICU), a beam tracking code in a chicane (ELEGANT) and an universal FEL simulating code (GENESIS), the effects of beam energy chirp and coherent synchrotron radiation (CSR) on EEHG operation are studied as well. In addition, several interesting issues concerning EEHG simulation are discussed.

  16. Flash CS5.5 The Missing Manual

    CERN Document Server

    Grover, Chris

    2011-01-01

    You can build everything from simple animations to full-fledged iOS and Android apps with Flash CS5.5, but learning this complex program can be difficult-unless you have this fully updated, bestselling guide. Learn how to create gorgeous Flash effects even if you have no programming experience. With Flash CS5.5: The Missing Manual, you'll move from the basics to power-user tools with ease. Learn animation basics. Discover how to turn simple ideas into stunning animations.Master Flash's tools. Learn the animation and effects tools with clear explanations and hands-on examples.Use 3D effects. R

  17. Empirical Optimization of Undulator Tapering at FLASH2 and Comparison with Numerical Simulations

    CERN Document Server

    Mak, Alan; Faatz, Bart; Werin, Sverker

    2016-01-01

    In a free-electron laser equipped with variable-gap undulator modules, the technique of undulator tapering opens up the possibility to increase the radiation power beyond the initial saturation point, thus enhancing the efficiency of the laser. The effectiveness of the enhancement relies on the proper optimization of the taper profile. In this work, a multidimensional optimization approach is implemented empirically in the x-ray free-electron laser FLASH2. The empirical results are compared with numerical simulations.

  18. Problems for determining the thermal conductivity of TBCs by laser-flash method

    OpenAIRE

    2008-01-01

    Purpose: The purpose of this paper was to investigate the parameters which effect the results of determining the thermal conductivity of thermal barrier coatings (TBCs) by laser-flash method.Design/methodology/approach: The air plasma-spray (APS) technique was used to deposition of two- and three-layered samples. Two-layered samples were composed of metal substrate (321 stainless steel), and ceramic top coat (8YSZ). Three-layered samples were composed of metal substrate (321 ...

  19. Empirical optimization of undulator tapering at FLASH2 and comparison with numerical simulations

    Energy Technology Data Exchange (ETDEWEB)

    Mak, Alan; Curbis, Francesca; Werin, Sverker [Lund Univ. (Sweden). MAX IV Laboratory; Faatz, Bart [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2016-08-15

    In a free-electron laser equipped with variable-gap undulator modules, the technique of undulator tapering opens up the possibility to increase the radiation power beyond the initial saturation point, thus enhancing the efficiency of the laser. The effectiveness of the enhancement relies on the proper optimization of the taper profile. In this work, a multidimensional optimization approach is implemented empirically in the X-ray free-electron laser FLASH2. The empirical results are compared with numerical simulations.

  20. Laser flash method for measurement of liquid metals heat transfer coefficients

    Science.gov (United States)

    Stankus, S. V.; Savchenko, I. V.

    2009-12-01

    New laser flash technique for the measurement of heat transfer coefficients of liquid metals is presented. The thermal diffusivity of the liquid mercury has been studied experimentally over the room temperature range. The thermal conductivity coefficient has been calculated with the use of the reference data on density and heat capacity. Analysis of systematic errors of the measurements has shown that the data error is about 3%. Comparison of the obtained results with data available in publications has proved their reliability.

  1. Restructuring of a flash A/D converter to improve SEU rad tolerance; Amelioration de la tolerance aux SEU d'un convertisseur A/N flash par restructuration

    Energy Technology Data Exchange (ETDEWEB)

    Monnier, T.; Roche, R.M. [Montpellier-2 Univ., Lab. d' Informatique de Robotique et de Microelectronique de Montpellier, CNRS, 34 (France); Corbiere, F. [SUPAERO, 31 - Toulouse (France)

    1999-07-01

    The purpose of this work is to present how structural changes in the conventional Flash Analog to Digital Converter can secure it for a harsh radiation environment. The method consists in a coupling of two complementary techniques: a robust reconfiguration of the logical structure joined to a design hardening of the individual blocks. This approach preserves the ADC performances. (authors)

  2. Animación con Flash

    OpenAIRE

    Agelet Ordobàs, Ferran; Villar Posada, Feliciano

    2009-01-01

    Flash es una aplicación informática producida por la empresa de software norteamericana Macromedia, que se utiliza principalmente para la generación de páginas web animadas e interactivas. Este programa se está convirtiendo en un estándar para la creación de contenidos animados y altamente interactivos para ser distribuidos en la Red. Este tutorial pretende recorrer el camino necesario para llegar a conocer las posibilidades de la aplicación sin experiencia previa. El usuario interesado tiene...

  3. 3D flash lidar imager onboard UAV

    Science.gov (United States)

    Zhou, Guoqing; Liu, Yilong; Yang, Jiazhi; Zhang, Rongting; Su, Chengjie; Shi, Yujun; Zhou, Xiang

    2014-11-01

    A new generation of flash LiDAR sensor called GLidar-I is presented in this paper. The GLidar-I has been being developed by Guilin University of Technology in cooperating with the Guilin Institute of Optical Communications. The GLidar-I consists of control and process system, transmitting system and receiving system. Each of components has been designed and implemented. The test, experiments and validation for each component have been conducted. The experimental results demonstrate that the researched and developed GLiDAR-I can effectively measure the distance about 13 m at the accuracy level about 11cm in lab.

  4. A Temporal Locality-Aware Page-Mapped Flash Translation Layer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Youngjae [ORNL; Gupta, Aayush [IBM Corporation, Almaden Research Center; Urgaonkar, Bhuvan [Pennsylvania State University

    2013-01-01

    The poor performance of random writes has been a cause of major concern which needs to be addressed to better utilize the potential of flash in enterprise-scale environments. We examine one of the important causes of this poor performance: the design of the flash translation layer (FTL) which performs the virtual-to-physical address translations and hides the erase-before-write characteristics of flash. We propose a complete paradigm shift in the design of the core FTL engine from the existing techniques with our Demand-Based Flash Translation Layer (DFTL) which selectively caches page- level address mappings. Our experimental evaluation using FlashSim with realistic enterprise-scale workloads endorses the utility of DFTL in enterprise-scale storage systems by demonstrating: 1) improved performance, 2) reduced garbage collection overhead and 3) better overload behavior compared with hybrid FTL schemes which are the most popular implementation methods. For example, a predominantly random-write dominant I/O trace from an OLTP application running at a large financial institution shows a 78% improvement in average response time (due to a 3-fold reduction in operations of the garbage collector), compared with the hybrid FTL scheme. Even for the well-known read-dominant TPC-H benchmark, for which DFTL introduces additional overheads, we improve system response time by 56%. Moreover, interestingly, when write-back cache on DFTL-based SSD is enabled, DFTL even outperforms the page-based FTL scheme, improving their response time by 72% in Financial trace.

  5. The photopic negative response of the blue-on-yellow flash-electroretinogram in glaucomas and normal subjects.

    Science.gov (United States)

    Wakili, Nina; Horn, Folkert K; Jünemann, Anselm G; Nguyen, Nhung X; Mardin, Christian Y; Korth, Matthias; Kremers, Jan

    2008-09-01

    The photopic negative response of the flash-electroretinogram driven by the middle- and long-wavelength cones has been shown to be reduced in non-human primates with experimental glaucoma and in human patients with glaucoma. The photopic negative response for the blue-sensitive response has been studied using a blue-green silent-substitution-technique on a red background. The aim of this study was to re-evaluate the value of the photopic negative response of the blue-sensitive pathway in glaucoma using a conventional flash-electroretinogram. In 37 eyes of 37 controls (age: 53 +/- 13.6 years) and 37 eyes of 37 patients with open-angle glaucoma of different perimetric visual field defects (age: 58.3 +/- 10 years; MD: 11.7 +/- 6.7 dB) of the Erlangen glaucoma registry Ganzfeld flash-electroretinograms (LKC, UTAS 3000) were recorded using blue Xenon-flashes of increasing photopic luminance (0.013, 0.018, 0.030, and 0.052 cd s/m(2); 440 nm) on a bright yellow background (238 cd/m(2); 550 nm) after 2 min of light adaptation. Amplitudes and implicit times of the photopic negative response and of L&M-cone- and S-cone-driven b-waves were compared between glaucomas and controls for all flash energies (unpaired t-test). The amplitudes of the photopic negative response were significantly reduced in glaucoma patients for all flash energies (P flash-electroretinogram are potentially useful in the evaluation of inner-retinal function in glaucoma.

  6. Flash Photolysis and Its Applications: Meeting in Honour of Sir George Porter, P.R.S. held in London, England on 14-16 July 1986,

    Science.gov (United States)

    1986-07-16

    dopachrome and reform dopa. By contrast, the cysteinyldopa quinones decayed via an acid-catalysed unimolecular cyclisation involving the cysteine side chain...porphyrin -dianion). Aeration of the photolysed solution causesimmediate reformation of the original porphyrin, with very little <%/ byproduct formation... ESTRUTURAL , COMPLEXO I INSTITUTO SUPERIOR TECNICO AV. ROVISCO PATS, 1096 LISBOA CODEX, PORTUGAL Reversed micelles have been used to mimic membrane

  7. A Photochemical Study of the Kinetics of the Reactions of NH2 with Phosphine, Ethylene, and Acetylene Using Flash Photolysis-Laser Induced Fluorescence.

    Science.gov (United States)

    1982-06-01

    1969, p. 83. (97) J. E. Huheey , "Inorganic Chemistry, Principles of Structure and Reactivity", 2nd Ed., Harper and Row, New York, 1978, pp. 842-850...74. (106) ibid. p. 28. (107) J. E. Huheey , "Inorganic Chemistry, Principles of Structure and Reactivity", 2nd Ed., Harper and Row, New York, 1978

  8. Flash Photolysis Experiment of o-Methyl Red as a Function of pH: A Low-Cost Experiment for the Undergraduate Physical Chemistry Lab

    Science.gov (United States)

    Larsen, Molly C.; Perkins, Russell J.

    2016-01-01

    A low-cost, time-resolved spectroscopy experiment appropriate for third year physical chemistry students is presented. Students excite o-methyl red in basic solutions with a laser pointer and use a modular spectrometer with a CCD array detector to monitor the transient spectra as the higher-energy cis conformer of the molecule converts back to the…

  9. Flash Photolysis Experiment of o-Methyl Red as a Function of pH: A Low-Cost Experiment for the Undergraduate Physical Chemistry Lab

    Science.gov (United States)

    Larsen, Molly C.; Perkins, Russell J.

    2016-01-01

    A low-cost, time-resolved spectroscopy experiment appropriate for third year physical chemistry students is presented. Students excite o-methyl red in basic solutions with a laser pointer and use a modular spectrometer with a CCD array detector to monitor the transient spectra as the higher-energy cis conformer of the molecule converts back to the…

  10. The attentional modulation of the flash-lag effect

    Directory of Open Access Journals (Sweden)

    M.V.C. Baldo

    2002-08-01

    Full Text Available If a dot is flashed in perfect alignment with a pair of dots rotating around the visual fixation point, most observers perceive the rotating dots as being ahead of the flashing dot (flash-lag effect. This perceptual effect has been interpreted to result from the perceptual extrapolation of the moving dots, the differential visual latencies between flashing and moving stimuli, as well as the modulation of attentional mechanisms. Here we attempted to uncouple the attentional effects brought about by the spatial predictability of the flashing dot from the sensory effects dependent on its visual eccentricity. The stimulus was a pair of dots rotating clockwise around the fixation point. Another dot was flashed at either the upper right or the lower left of the visual field according to three separate blocked situations: fixed, alternate and random positions. Twenty-four participants had to judge, in all three situations, the location of the rotating dots in relation to the imaginary line connecting the flashing dot and the fixation point at the moment the dot was flashed. The flash-lag effect was observed in all three situations, and a clear influence of the spatial predictability of the flashing dot on the magnitude of the perceptual phenomenon was revealed, independently of sensory effects related to the eccentricity of the stimulus in the visual field. These findings are consistent with our proposal that, in addition to sensory factors, the attentional set modulates the magnitude of the differential latencies that give rise to the flash-lag phenomenon.

  11. Literature survey of the aqueous chemistry of technetium related to photolysis. [115 references

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, H.A.

    1981-07-01

    A literature survey was made to accumulate information about the chemistry of technetium as it relates to photolysis. The electrochemical potentials and the reactions of the various technetium compounds and complexes are discussed, along with the various absorption spectra of the different species. The TcCl/sub 6//sup 2 -/ ion has been shown to be photochemically active in HCl solutions. Hexachlorotechnetate(IV) is oxidized when exposed to sunlight in concentrated HCl. A ligand change occurs when it is exposed to either 254- or 34-nm radiation in more dilute HCl. No other photolysis reactions were found in the literature. It is possible that, under appropriate conditions, other valence states of technetium would be photochemically active, resulting in either redox or ligand exchange reactions. Proposals for investigating the photochemical reduction of the pertechnetate in HNO/sub 3/ and other media are discussed.

  12. Postcolumn photolysis of pesticides for fluorometric determination by high-performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Miles, C.J.; Moye, H.A.

    1988-02-01

    A high-performance liquid chromatography postcolumn reaction detector that employs UV photolysis with an optional reaction by using o-phthalaldehyde-2-mercaptoethanol (OPA-MERC) followed by fluorescence detection was found to be useful for several classes of pesticides. In the presence of the OPA-MERC reagent, most carbamates, carbamoyl oximes, carbamothioic acids, and substituted ureas gave a sensitive response while the response of dithiocarbamates, phenylamides, and phenylcarbamates varied. The response of most of the pesticides tested was significantly affected by the solvent used. Method detection limits for aldicarb sulfoxide, aldicarb, propoxur, thiram, and neburon in ground water were 2.5, 2.3, 3.3, 3.8, and 2.0 ..mu..g/L, respectively. In the absence of OPA-MERC reagent, several of the substituted aromatic compounds also gave strong fluorescence after photolysis. This detector is applicable to a broad range of nitrogenous pesticides.

  13. Non-invasive bleaching of the human lens by femtosecond laser photolysis

    DEFF Research Database (Denmark)

    Kessel, L.; Eskildsen, Lars; Poel, Mike van der

    2010-01-01

    were susceptible to photobleaching by a non-invasive procedure and whether this would lead to optical rejuvenation of the lens. Methodology/Principal Findings: Nine human donor lenses were treated with an 800 nm infra-red femtosecond pulsed laser in a treatment zone measuring 1 x 1 x 0.52 mm. After...... laser treatment the age-induced yellow discoloration of the lens was markedly reduced and the transmission of light was increased corresponding to an optical rejuvenation of 3 to 7 years. Conclusions/Significance: The results demonstrate that the age-induced yellowing of the human lens can be bleached...... by a non-invasive procedure based on femtosecond laser photolysis. Cataract is a disease associated with old age. At the current technological stage, lens aging is delayed but with a treatment covering the entire lens volume complete optical rejuvenation is expected. Thus, femtosecond photolysis has...

  14. Decolorization of some azo dyes by direct photolysis and H2O2/UV processes

    Directory of Open Access Journals (Sweden)

    Keiko Takashima

    2009-03-01

    Full Text Available The decolorization of acid orange 7 (AO7, direct orange 34 (DO 34, direct red 23 (DR23 and direct yellow 86 (DY86 azo dyes was investigated by direct photolysis and hydrogen peroxide-assisted photodegradation respectively in closed and open reactor to the atmosphere under UV radiation at natural pHs and 30 ºC. Four azo dyes decolorization (1,5x10-4 mol L-1 was not significant in presence of H2O2 in closed reactor during 3 h irradiation, whereas in open reactor, the decolorization was respectively 96, 82, 32, and 45% for AO7, DO34, DR23 and DY86. The decolorization by direct photolysis in open reactor was significantly higher in comparison to closed one.

  15. Dependence of Upper Atmosphere Photochemistry on the Shape of the Diurnal Cycle of the Photolysis Rates

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A photochemical model of the atmosphere constitutes a non-linear, non-autonomous dynamical system, enforced by the Earth's rotation. Some studies have shown that the region of the mesopause tends towards non-linear responses such as period-doubling cascades and chaos. In these studies, simple approximations for the diurnal variations of the photolysis rates are assumed. The goal of this article is to investigate what happens if the more realistic, calculated photolysis rates are introduced. It is found that,if the usual approximations-sinusoidal and step fiunctions-are assumed, the responses of the system are similar: it converges to a 2-day periodic solution. If the more realistic, calculated diurnal cycle is introduced, a new 4-day subharmonic appear.

  16. Pressure dependent deuterium fractionation in the formation of molecular hydrogen in formaldehyde photolysis

    DEFF Research Database (Denmark)

    Nilsson, Elna Johanna Kristina; Andersen, Vibeke Friis; Skov, Henrik;

    2009-01-01

    the channels has been estimated using available values for the absorption 10 cross section and quantum yield. As a result of the change in pressure with altitude the isotope effect for production of molecular hydrogen is found to change from a value of kH/kD=1.8±0.2 at the surface to unity at 50 km....... The relative importance of the two product channels changes with altitude as a result of changes in both pressure and actinic flux. The study concludes that the D of photochemical hydrogen produced in 15 situ will increase substantially with altitude.......The pressure dependence of the relative photolysis rates of HCHO and HCDO has been investigated using a new photochemical reactor at the University of Copenhagen. The relative photolysis rate of HCHO vs. HCDO under UVA lamp irradiation was mea- 5 sured at total pressures of 50, 200, 400, 600...

  17. Determination of common anions in oxalate by ion chromatography coupled with UV photolysis pretreatment

    Institute of Scientific and Technical Information of China (English)

    Sheng Lin Cao; Ming Li Ye; Wei De Lv; Guang Wen Pan; Ting Ting Zhang; Zhong Yang Hu; Li Na Liang; Yan Zhu

    2012-01-01

    A new and simple method was developed to determine anions in oxalate of analytical reagent grade.After UV photolysis with optimal 1% H2O2 in 10,000 mg/L oxalate in the fabricated photoreactor,sample was directly injected into IC system.Satisfactory linearity,detections limits,good repeatability and spiked recovery were obtained.The method was successfully applied to determine anions in two commercial oxalate samples.

  18. Identification of Products of Merocyanine 540 Decay by Photolysis and Thermolysis

    Science.gov (United States)

    Bazyl', O. K.; Svetlichnyi, V. A.

    2016-08-01

    Possible products of merocyanine 540 decay are studied using quantum-chemical calculations. The results of calculation are compared with experimental investigations of the spectral-luminescent properties, and the products of photo- and thermodecay of the merocyanine 540 molecule in water are identified. It is shown that different products are formed by thermolysis (decay in the ground electronic state S0) and photolysis (decay in an excited electronic state).

  19. Kinetics of the photolysis and OH reaction of 4-hydroxy-4-methyl-2-pentanone: Atmospheric implications

    Science.gov (United States)

    Aslan, L.; Laversin, H.; Coddeville, P.; Fittschen, C.; Roth, E.; Tomas, A.; Chakir, A.

    2017-02-01

    This study provides the first kinetic and mechanistic study of the photolysis of 4-hydroxy-4-methyl-2-pentanone (4H4M2P) and the determination of the temperature dependence of the relative rate coefficient for the reaction of OH radicals with 4H4M2P. The UV absorption spectrum of 4H4M2P was determined in the spectral range 200-360 nm. The photolysis frequency of this compound in the atmosphere was evaluated relative to actinometers and found to be J4 H 4M 2 P atm = 4.2 ×10-3h-1 , corresponding to a lifetime of about 10 days. Using 4H4M2P cross section measurements, an atmospheric effective quantum yield of 0.15 was calculated. The main primary photolysis products were acetone (121 ± 4) % and formaldehyde (20 ± 1) %. A low methanol yield of (3.0 ± 0.3) % was also determined. These results enabled us to propose a mechanistic scheme for the photolysis. Rate coefficients for the reaction of 4H4M2P with OH radicals were determined over the temperature range 298-354 K and the following Arrhenius expression was obtained: kOH+4M4H2P = (1.12 ± 0.40) × 10-12exp(461.5 ± 60/T) cm3 molecule-1 s-1. The lifetimes of 4H4M2P due to reaction with OH radicals has been estimated to ∼2.5 days and indicates that the gas-phase reaction with the OH could be the main loss process for this compound.

  20. Flash pyrolysis fuel oil: BIO-POK

    Energy Technology Data Exchange (ETDEWEB)

    Gust, S. [Neste Oy, Porvoo (Finland)

    1995-12-31

    Flash pyrolysis oil from Ensyn Tech., Canada and Union Fenosa, Spain was combusted with simple pressure atomisation equipment commonly used with light fuel oils in intermediate size (0.1-1 MW) boilers. With a number of modifications to the combustion system, carbon monoxide (CO) and nitrous oxide (NO{sub x}) could be reduced to acceptable levels: CO < 30 ppm and NO{sub x} < 140 ppm. Particulate emissions which were initially very high (Bacharach 4-5) were reduced (Bach. 2-3) by system changes but are still higher than from light fuel oil (Bach. <1). The modifications to the combustion system were: acid resistant progressive cavity pump, higher oil preheat temperature and higher oil pressure than for light fuel oils, refractory section between burner and boiler warmed up to at least 800 deg C. In addition, it was necessary to store pyrolysis oil samples under inert conditions to prevent oxidation and to rinse nozzles with alcohol after shutdown to prevent coking. The complexity and cost of these system modifications are considered to be too great for current grades of flash pyrolysis oil to be sold as a light fuel oil replacement. Improvements to fuel quality will be necessary. The main improvements are lowering of viscosity and improving of stability

  1. Honeywell optical investigations on FLASH program

    Science.gov (United States)

    O'Rourke, Ken; Peterson, Eric; Yount, Larry

    1995-05-01

    The increasing performance and reduction of life cycle cost requirements placed on commercial and military transport aircraft are resulting in more complex, highly integrated aircraft control and management systems. The use of fiber optic data transmission media can make significant contributions in achieving these performance and cost goals. The Honeywell portion of Task 2A on the Fly-by-Light Advanced System Hardware (FLASH) program is evaluating a Primary Flight Control System (PFCS) using pilot and copilot inputs from Active Hand Controllers (AHC) which are optically linked to the primary flight Control Computers (PFCC). Customer involvement is an important element of the Task 2A activity. Establishing customer requirements and perspectives on productization of systems developed under FLASH are key to future product success. The Honeywell elements of the PFCS demonstrator provide a command path that is optically interfaced from crew inputs to commands of distributed, smart actuation subsystems commands. Optical communication architectures are implemented using several protocols including the new AS-1773A 20 Mbps data bus standard. The interconnecting fiber optic cable plant is provided by our Task 1A teammate McDonnell Douglas Aerospace (West). Fiber optic cable plant fabrication uses processed, tools and materials reflecting necessary advances in manufacturing required to make fly-by-light avionics systems marketable.

  2. Nanocrystalline magnetic materials obtained by flash annealing

    Directory of Open Access Journals (Sweden)

    R.K. Murakami

    1999-04-01

    Full Text Available The aim of the present work was to produce enhanced-remanence nanocrystalline magnetic material by crystallizing amorphous or partially amorphous Pr4.5Fe77B18.5 alloys by the flash annealing process, also known as the dc-Joule heating process, and to determine the optimal conditions for obtaining good magnetic coupling between the magnetic phases present in this material. Ribbons of Pr4.5Fe77B18.5 were produced by melt spinning and then annealed for 10-30 s at temperatures 500 - 640 °C by passing current through the sample to develop the enhanced-remanence nanocrystalline magnetic material. These materials were studied by X-ray diffraction, differential thermal analysis and magnetic measurements. Coercivity increases of up to 15% were systematically observed in relation to furnace-annealed material. Two different samples were carefully examined: (i a sample annealed at 600 °C which showed the highest coercive field Hc and remanence ratio Mr/Ms and (ii a sample annealed at 520 °C which showed phase separation in the second quadrant demagnetization curve. Our results are in agreement with other studies which show that flash annealing improves the magnetic properties of some amorphous ferromagnetic ribbons.

  3. Comparison between UV and VUV photolysis for the pre- and post-treatment of coking wastewater.

    Science.gov (United States)

    Xing, Rui; Zheng, Zhongyuan; Wen, Donghui

    2015-03-01

    In this study, ultraviolet (UV) and vacuum ultraviolet (VUV) photolysis were investigated for the pre-treatment and post-treatment of coking wastewater. First, 6-fold diluted raw coking wastewater was irradiated by UV and VUV. It was found that 15.9%-35.4% total organic carbon (TOC) was removed after 24 hr irradiation. The irradiated effluent could be degraded by the acclimated activated sludge. Even though the VUV photolysis removed more chemical oxygen demand (COD) than UV, the UV-irradiated effluent demonstrated better biodegradability. After 4 hr UV irradiation, the biological oxygen demand BOD5/COD ratio of irradiated coking wastewater increased from 0.163 to 0.224, and its toxicity decreased to the greatest extent. Second, the biologically treated coking wastewater was irradiated by UV and VUV. Both of them were able to remove 37%-47% TOC within 8 hr irradiation. Compared to UV, VUV photolysis could significantly improve the transparency of the bio-treated effluent. VUV also reduced 7% more ammonia nitrogen (NH4+-N), 17% more nitrite nitrogen (NO2--N), and 18% more total nitrogen (TN) than UV, producing 35% less nitrite nitrogen (NO3--N) as a result. In conclusion, UV irradiation was better in improving the biodegradability of coking wastewater, while VUV was more effective at photolyzing the residual organic compounds and inorganic N-species in the bio-treated effluent.

  4. Nanosecond photolysis of rhodopsin: evidence for a new, blue-shifted intermediate.

    Science.gov (United States)

    Hug, S J; Lewis, J W; Einterz, C M; Thorgeirsson, T E; Kliger, D S

    1990-02-13

    Early photolysis intermediates of native bovine rhodopsin (RHO) are investigated by nanosecond laser photolysis near physiological temperature. Absorption difference spectra are collected after excitation with 477-, 532-, and 560-nm laser pulses of various energies and with 477-nm laser excitation at 5, 12, 17, 21, and 32 degrees C. The data are analyzed by using singular-value decomposition (SVD) and a global exponential fitting routine. Two rate constants associated with distinct spectral changes are observed during the time normally associated with the decay of bathorhodopsin to lumirhodopsin. Various models consistent with this observation are considered. A sequential model in which there is a reversible step between a bathorhodopsin intermediate and a new intermediate (BSI), which is blue-shifted relative to lumirhodopsin, is shown to best fit the data. The temperature dependence of the observed and calculated rate constants leads to linear Arrhenius plots. Extrapolation of the temperature dependence suggests that BSI should not be observable after rhodopsin photolysis at temperatures below -100 degrees C. The results are discussed with regard to the artificial visual pigments cis-5,6-dihydroisorhodopsin and 13-demethylrhodopsin. It is proposed that the rate of the BATHO to BSI transition is limited by the relaxation of the strained all-trans-retinal chromophore within a tight protein environment. The transition to LUMI involves chromophore relaxation concurrent with protein relaxation. While the first process is strongly affected by changes in the chromophore, the second transition seems to be determined more by protein relaxation.

  5. Photolysis of pure solid O3 and O2 films at 193 nm

    CERN Document Server

    Raut, U; Famá, M; Baragiola, R A

    2010-01-01

    We studied quantitatively the photochemistry of solid O3 and O2 films at 193 nm and 22 K with infrared spectroscopy and microgravimetry. Photolysis of pure ozone destroyed O3, but a small amount of ozone remained in the film at high fluence. Photolysis of pure O2 produced O3 in an amount that increased with photon fluence to a stationary level. For both O2 and O3 films, the O3:O2 ratio at saturation is 0.03, nearly 10-30 times larger than those obtained in gas phase photolysis. This enhancement is attributed to the increased photodissociation of O2 due to photoabsorption by O2 dimers, a process significant at solid state densities. We obtain initial quantum yield for ozone synthesis from solid oxygen, {\\Phi} (O3) = 0.18 and for destruction of ozone and oxygen in their parent solids, {\\Phi} (- O3) = 1.7 and {\\Phi} (-O2) = 0.28. Combined with known photoabsorption cross sections, we estimate probabilities for germinate recombination of 0.15 for O3 fragments and 0.90 for oxygen atoms from O2 dissociation. Using ...

  6. Vacuum UV photolysis of CO 2. Rare-gas oxide formation in matrices

    Science.gov (United States)

    Fournier, J.; Mohammed, H. H.; Deson, J.; Maillard, D.

    1982-08-01

    In this paper, we report experimental results obtained upon photolysis of CO 2 trapped at low concentrations (0.1%) in neon, argon and krypton matrices. The mixture are photolysed using a xenon resonance lamp emitting photons at 8.4 eV. Only in a neon matrix does the photolysis of CO 2 lead to O( 1D) → O( 3P) emission. Furthermore, oxygen atoms are shown to diffuse at all temperatures in a neon matrix (as detected by molecular oxygen emission), whereas in the other matrices this occurs only when the sample is warmed even though irradiation is performed at high temperature. In argon and krypton matrices, O( 1S) → O( 1D) emission is observed even though there is not enough energy to form an O( 1S) atom in a primary photodecomposition process. This suggests that O( 1D) becomes bound to argon or krypton atoms as a stable rare-gas oxide RGO excimer, which is subsequently excited and photolysed by 8.4 eV photons. These observed features are explained using a model for the interaction between oxygen ( 3P, 1D, 1S) and rare-gas atoms ( 1S) which had previously been proposed to account for the emission spectra of oxygen atoms observed during photolysis of oxygenated compounds.

  7. Photochemistry of insecticide imidacloprid:direct and sensitized photolysis in aqueous medium

    Institute of Scientific and Technical Information of China (English)

    ZHENG Wei; LIU Wei-ping; WEN Yue-zhong; Sang-jin Lee

    2004-01-01

    The direct and sensitized photodegradations of imidacloprid, 1-(6-chloro-3-pyridinylmethyl)-N-nitro-2-imidazolidinimine. were investigated in aqueous solution and with and without various photo-sensitizers. Results of the study revealed that the intensity of lamp-house and irradiation wavelength had significant effects on the photolysis of imidacloprid. Complete degradation of 20 mg/L imidacloprid in aqueous phase was observed in 40 min under ultraviolet(UV) irradiation system, suggesting the ultraviolet ray played significant role in direct photolysis of imidacloprid. The additions of various photo-sensitizers lead to improve the degradation efficiency of imidacloprid under the irradiation of black light fluorescent lamp. TiO2 was the most efficient in the photo-catalytic degradation of imidacloprid among other photo-sensitizers in used this study. However, addition of acetone inhibited the photolysis of imidacloprid under the irradiation of UV, indicating the occurrence of competition between acetone and imidacloprid for photos. Mineralization of the imidacloprid was examined to clarify the final photochemical degradation products of the insecticide which were CO2, Cl- and NO3- . Complete photo-oxidation of nitrogen to NO3- occurred very slowly via the intermediate formation of NH4+ and NO2- .

  8. Comparison of the degradations of diphenamid by homogeneous photolysis and heterogeneous photocatalysis in aqueous solution.

    Science.gov (United States)

    Liang, Hai-chao; Li, Xiang-zhong; Yang, Yin-hua; Sze, Kong-hung

    2010-06-01

    In this work, the homogeneous and heterogeneous degradations of diphenamid (DPA) in aqueous solution were conducted by direct photolysis with UVC (254nm) and by photocatalysis with TiO(2)/UVA (350nm), and the experimental results were compared. It was found that the homogeneous photolysis by UVC irradiation alone was quite efficient to degrade DPA up to 100% after 360min, but was very inefficient to mineralize its intermediates in terms of dissolved organic carbon reduction of only 8%. In contrast, the heterogeneous photocatalysis with TiO(2)/UVA showed relatively a lower degree of DPA degradation (51%), but a higher degree of its mineralization (11%) after 360min. These results reveal that the photocatalysis process has relatively poor selectivity to degrade different compounds including various intermediates from the DPA degradation, which is beneficial to its mineralization. In addition, over 20 intermediates were identified by LC-MS and (1)H NMR analyses. Based on the identified intermediates, the reaction mechanisms and the detailed pathways of the DPA degradation by photolysis and photocatalysis were proposed, and are presented in this paper.

  9. Photolysis of flumequine: identification of the major phototransformation products and toxicity measures.

    Science.gov (United States)

    Sirtori, Carla; Zapata, Ana; Gernjak, Wolfgang; Malato, Sixto; Agüera, Ana

    2012-07-01

    Direct photolysis of flumequine (FLU, 20 mg L(-1)) in different types of water (demineralised water (DW) and synthetic seawater (SW)), was conducted in a Suntest CPS+solar simulator to evaluate its persistence and toxicity, and to identify the major phototransformation products (PTPs) generated during photolysis in DW. It was observed that FLU is susceptible to transformation when subjected to direct solar radiation. The composition of the water affects the FLU degradation kinetics, which is slower in SW. Photolytic transformation products generated during direct photolysis were identified by liquid chromatography-time of flight-mass spectrometry (LC-TOF-MS). Fourteen PTPs generated in DW were identified. The transformation of FLU begins with the opening of the heterocyclic ring by oxidation of the double bond. Loss of the fluorine atom and the hydroxylation of the aromatic ring also appear as the majority, especially in the early stages. Comparative acute toxicity evaluation by Vibrio fischeri and Daphnia magna bioassays was performed for the first and last irradiated solutions in both matrices studied. These bioassays demonstrated that in the SW matrix, the most persistent PTPs are highly toxic to D. magna but less so to V. fischeri.

  10. Photolysis of Iron (III) carboxylate complexes relevant for tropospheric aqueous particles and cloud droplets

    Science.gov (United States)

    Herrmann, H.; Weller, C.; Bräuer, P.; Tilgner, A.

    2012-12-01

    Absorption spectra and Fe(II) quantum yields of iron(III) coordination complexes with oxalate, malonate, succinate, glutarate, tartronate, tartrate, gluconate, glyoxalate and pyruvate were experimentally determined. Measured quantum yields of malonate, glutarate and gluconate complexes are in the range of 0.02 tartrate, pyruvate, glyoxylate and tartronate complexes show values between 0.12 tartrate and, surprisingly, in the case of succinate complexes a higher quantum yield was observed at 351 nm under increased oxygen concentrations in solution. In the case of oxalate, a dependence of the quantum yield on the initial concentration of iron(III) oxalato complexes was observed. A kinetic simulation of the reaction system after the photolysis was performed for oxalate, succinate, glyoxalate and tartrate complexes to characterize the influence of secondary thermal reactions on the quantum yield. A tropospheric chemistry simulation with the multiphase chemistry mechanism CAPRAM involving the photolysis of the studied complexes and subsequent reactions of the resulting species shows that the contribution of the iron complex photochemistry to the formation of oxidants such as the hydroperoxyl radical and its anion, the hydroxyl radical and H2O2 is low in comparison to other sources. However, it is shown that Fe(III) complex photolysis represents a major sink for some ligands in addition to the oxidation via free radicals.

  11. Is Amino-Acid Homochirality Due To Asymmetric Photolysis In Space?

    CERN Document Server

    Cerf, C

    1999-01-01

    Amino acids occurring in proteins are, with rare exceptions, exclusively of the L-configuration. Among the many scenarios put forward to explain the origin of this chiral homogeneity (i.e., homochirality), one involves the asymmetric photolysis of amino acids present in space, triggered by circularly polarized UV radiation. The recent observation of circularly polarized light (CPL) in the Orion OMC-1 star-forming region (Bailey et al. 1998, Science 281, 672) has been presented as providing a strong validation of this scenario. The present paper reviews the situation. It is stressed for example that one important condition for the asymmetric photolysis by CPL to be at the origin of the terrestrial homochirality of natural amino acids is generally overlooked, namely, the asymmetric photolysis should favour the L-enantiomer for ALL the primordial amino acids involved in the genesis of life (i.e., biogenic amino acids). Although this condition is probably satisfied for aliphatic amino acids, some non-aliphatic am...

  12. Initial Electric Field Changes of Lightning Flashes in Two Thunderstorms

    Science.gov (United States)

    Marshall, T. C.; Stolzenburg, M.; Karunarathne, S.; Chapman, R.

    2015-12-01

    In a study of lightning initiation, Marshall et al. [2014, JGR Atmospheres] found that an initial electric field change (IEC) occurred before the initial breakdown (IB) pulses in 18 cloud-to-ground (CG) flashes and in 18 intracloud (IC) flashes. Because the IECs were small in amplitude and slowly developing (i.e., primarily electrostatic events), they were only detected by sensors within the reversal distance of each flash. In this presentation we report on a search for IECs in two small Florida thunderstorms that occurred close to several E-change sensors. One storm had 57 flashes; the other had only 13 flashes. The key result is that 69 of the 70 flashes began with detectable IECs. For the one flash without a detectable IEC, the closest sensor was at the reversal distance, presumably masking the IEC. Three of the flashes analyzed seemed to begin twice, in the sense that they had two sets of IB pulses; each beginning was preceded by an IEC.

  13. Assessment of Vulnerability to Extreme Flash Floods in Design Storms

    Directory of Open Access Journals (Sweden)

    Hyun Il Choi

    2011-07-01

    Full Text Available There has been an increase in the occurrence of sudden local flooding of great volume and short duration caused by heavy or excessive rainfall intensity over a small area, which presents the greatest potential danger threat to the natural environment, human life, public health and property, etc. Such flash floods have rapid runoff and debris flow that rises quickly with little or no advance warning to prevent flood damage. This study develops a flash flood index through the average of the same scale relative severity factors quantifying characteristics of hydrographs generated from a rainfall-runoff model for the long-term observed rainfall data in a small ungauged study basin, and presents regression equations between rainfall characteristics and the flash flood index. The aim of this study is to develop flash flood index-duration-frequency relation curves by combining the rainfall intensity-duration-frequency relation and the flash flood index from probability rainfall data in order to evaluate vulnerability to extreme flash floods in design storms. This study is an initial effort to quantify the flash flood severity of design storms for both existing and planned flood control facilities to cope with residual flood risks due to extreme flash floods that have ocurred frequently in recent years.

  14. Sunshine Trading: Flashes of Trading Intent at the NASDAQ

    NARCIS (Netherlands)

    J.A. Skjeltorp (Johannes); E. Sojli (Elvira); W.W. Tham (Wing Wah)

    2012-01-01

    textabstractWe use the introduction and the subsequent removal of the flash order facility (an actionable indication of interest, IOI) from the NASDAQ as a natural experiment to investigate the impact of voluntary disclosure of trading intent on market quality. We find that flash orders significantl

  15. Assessment of vulnerability to extreme flash floods in design storms.

    Science.gov (United States)

    Kim, Eung Seok; Choi, Hyun Il

    2011-07-01

    There has been an increase in the occurrence of sudden local flooding of great volume and short duration caused by heavy or excessive rainfall intensity over a small area, which presents the greatest potential danger threat to the natural environment, human life, public health and property, etc. Such flash floods have rapid runoff and debris flow that rises quickly with little or no advance warning to prevent flood damage. This study develops a flash flood index through the average of the same scale relative severity factors quantifying characteristics of hydrographs generated from a rainfall-runoff model for the long-term observed rainfall data in a small ungauged study basin, and presents regression equations between rainfall characteristics and the flash flood index. The aim of this study is to develop flash flood index-duration-frequency relation curves by combining the rainfall intensity-duration-frequency relation and the flash flood index from probability rainfall data in order to evaluate vulnerability to extreme flash floods in design storms. This study is an initial effort to quantify the flash flood severity of design storms for both existing and planned flood control facilities to cope with residual flood risks due to extreme flash floods that have ocurred frequently in recent years.

  16. Microstructure of wood charcoal prepared by flash heating

    NARCIS (Netherlands)

    Kurosaki, F; Ishimaru, K; Hata, T; Bronsveld, P; Kobayashi, E; Imamura, Y

    2003-01-01

    Carbonized wood prepared by flash heating at 800 degreesC for I h shows a different microstructure and surface chemical structure than char formed after slow heating at 4 degreesC/min to 800 degreesC for I h. Flash heating produces pores that are surrounded by aggregates of carbon structures 25 to 1

  17. Flash ionisation signature in coherent cyclotron emission from Brown Dwarfs

    CERN Document Server

    Vorgul, Irena

    2016-01-01

    Brown dwarfs form mineral clouds in their atmospheres, where charged particles can produce large-scale discharges in form of lightning resulting in a substantial sudden increase of local ionisation. Brown dwarfs are observed to emit cyclotron radio emission. We show that signatures of strong transient atmospheric ionisation events (flash ionisation) can be imprinted on a pre-existing radiation. Detection of such flash ionisation events will open investigations into the ionisation state and atmospheric dynamics. Such ionisation events can also result from explosion shock waves, bursts or eruptions. We present an analytical model that describes the modulation of a pre-existing electromagnetic radiation by a time-dependent (flash) conductivity that is characteristic for flash ionisation events like lightning. Our conductivity model reproduces the conductivity function derived from observations of Terrestrial Gamma Ray Flashes, and is applicable to astrophysical objects with strong temporal variations in the loca...

  18. Lightning Mapping Array flash detection performance with variable receiver thresholds

    Science.gov (United States)

    Chmielewski, Vanna C.; Bruning, Eric C.

    2016-07-01

    This study characterizes Lightning Mapping Array performance for networks that participated in the Deep Convective Clouds and Chemistry field program using new Monte Carlo and curvature matrix model simulations. These open-source simulation tools are readily adapted to real-time operations or detailed studies of performance. Each simulation accounted for receiver threshold and location, as well as a reference distribution of source powers and flash sizes based on thunderstorm observations and the mechanics of station triggering. Source and flash detection efficiency were combined with solution bias and variability to predict flash area distortion at long ranges. Location errors and detection efficiency were highly dependent on the station configuration and thresholds, especially at longer ranges, such that performance varied more than expected across different networks and with azimuth within networks. Error characteristics matched prior studies, which led to an increase in flash distortion with range. Predicted flash detection efficiency exceeded 95% within 100 km of all networks.

  19. Improving flash flood frequency analyses by using non-systematic dendrogeomorphic data

    Science.gov (United States)

    Mediero, Luis; María Bodoque, Jose; Garrote, Julio; Ballesteros-Cánovas, Juan Antonio; Aroca-Jimenez, Estefania

    2017-04-01

    Flash floods have a rapid hydrological response in catchments with short lag times, characterized by ''peaky'' hydrographs. The peak flows are reached within a few hours, thus giving little or no advance warning to prevent and mitigate flood damage. As a result, flash floods may result in a high social risk, as shown for instance by the 1997 Biescas disaster in Spain. The analysis and management of flood risk are clearly conditioned by data availability, especially in mountain areas where usually flash-floods occur. Nevertheless, in mountain basins there is often short data series available that are not accurate in terms of statistical significance. In addition, when flow data is ready for use maximum annual values are generally not as reliable as average flow values, since conventional stream gauge stations may not record the extreme floods, leading to gaps in the time series. Dendrogeomorphology has been shown to be especially useful for improving flood frequency analyses in catchments where short flood series limit the use of conventional hydrological methods. This study presents pros and cons of using a given probability distribution function, such as the Generalized Extreme Value (GEV), and Bayesian Markov Chain Monte Carlo (MCMC) methods to account for non-systematic data provided by dendrogeomorphic techniques, in order to asses flood quantile estimates accuracy. To this end, we have considered a set of locations in Central Spain, where systematic flow available at a gauging site can be extended with non-systematic data obtained from implementation of dendrogeomorphic techniques.

  20. Features of positive ground flashes observed in Kathmandu Nepal

    Science.gov (United States)

    Adhikari, Pitri Bhakta; Sharma, Shriram; Baral, Kedarnath

    2016-07-01

    Lightning vertical electric fields pertinent to the subtropical thunderstorms occurring over the rugged terrain have been measured and recorded at a hilly station Kathmandu, Nepal. In the present work, waveforms of the positive ground flashes have been selected from all the records and were analyzed. To the best of our knowledge, this is the first time that fine structure of electric field signature pertinent to the positive return stroke; have been analyzed and presented from Nepal. One hundred and thirty three (133) of the total of four hundred twenty-five (425) flashes were selected from seven thunderstorm days and analyzed. Of the data recorded for seven days, 133 flashes (31.3%) were positive flashes and 276 flashes (64.9%) were cloud flashes. Majority of the positive ground flashes were found to be single stroke ones, whereas, the average number of strokes per flash is found to be 1.1 with a maximum value of 4. Majority of the positive ground flashes were found either lacking the initial breakdown process and the leader stage or these processes could not be detected. The return strokes are found to be succeeded by large in cloud activity in the continuing current portion of the flash. The average zero-crossing time of the positive return strokes was found to be 60.45 μs with a range of 447.81 μs and the average rise time was found to be 9.44 μs with a range of 42.56 μs.

  1. Mechanisms of cutaneous vasodilation during the postmenopausal hot flash

    Science.gov (United States)

    Low, David A.; Hubing, Kimberley A.; Del Coso, Juan; Crandall, Craig G.

    2010-01-01

    Objective Menopausal hot flashes can seriously disrupt the lives of symptomatic women. The physiological mechanisms of the hot flash efferent responses, particularly in the cutaneous circulation, are not completely understood. The aim of this study was to examine the mechanisms of increases in skin blood flow during the postmenopausal hot flash in symptomatic women. Methods Healthy postmenopausal women rested in a temperature controlled laboratory while responses prior to and during hot flashes were recorded for three unique protocols. Protocols 1 and 2: Women were locally pretreated with an intradermal injection of botulinum toxin A (BTX; blocks the release of neurotransmitters from sympathetic cholinergic nerves) in the forearm (protocol 1) and in the glabellar region (protocol 2). Protocol 3: Skin sympathetic nerve activity from the peroneal nerve was recorded, along with skin blood flow and sweating within the region innervated by that neural signal. Skin blood flow was indexed using laser-Doppler flowmetry at BTX-treated and adjacent untreated control sites. The onset of a hot flash was objectively identified as a transient and pronounced elevation of sternal sweat rate. Results The elevation in forearm (protocol 1) and glabellar skin blood flow (protocol 2) during hot flashes were attenuated at BTX sites relative to adjacent untreated sites (P<0.05 for both protocols). In protocol 3, skin sympathetic nerve activity significantly increased during hot flashes and returned to pre-flash levels following the hot flashes. Conclusion Elevations in skin blood flow during the postmenopausal hot flash are neurally mediated primarily through BTX sensitive nerves; presumably sympathetic cholinergic. PMID:21107299

  2. The E8 Lattice and Error Correction in Multi-Level Flash Memory

    CERN Document Server

    Kurkoski, Brian M

    2010-01-01

    A construction using the E8 lattice and Reed-Solomon codes for error-correction in flash memory is given. Since E8 lattice decoding errors are bursty, a Reed-Solomon code over GF($2^8$) is well suited. This is a type of trellis-coded modulation, where the Euclidean distance of the lattice (which is an eight-dimensional constellation) is combined with the Hamming distance of the code. This system is compared with the conventional technique for flash memories, BCH codes using Gray-coded PAM. The described construction has a performance advantage of 1.7 to 2.0 dB for an uncoded data density of 3 bits/cell.

  3. Cultivation of Scenedesmus obliquus in liquid hydrolysate from flash hydrolysis for nutrient recycling.

    Science.gov (United States)

    Barbera, Elena; Sforza, Eleonora; Kumar, Sandeep; Morosinotto, Tomas; Bertucco, Alberto

    2016-05-01

    The production of biofuels from microalgae is associated with high demands of nutrients (nitrogen and phosphorus) required for growth. Recycling nutrients from the residual biomass is essential to obtain a sustainable production. In this work, the aqueous phase obtained from flash hydrolysis of Scenedesmus sp. was used as cultivation medium for a microalga of the same genus, to assess the feasibility of this technique for nutrient recycling purposes. Batch and continuous cultivations were carried out, to determine growth performances in this substrate compared to standard media, and verify if a stable biomass production could be obtained. In continuous experiments, the effect of hydrolysate inlet concentration and of residence time were assessed to optimize nutrient supply in relation to productivity. Results obtained show that nutrient recycling is feasible by treating biomass with flash hydrolysis, and Scenedesmus is capable of recycling large amounts of recovered nutrients.

  4. Looking for Similarities Between Lowland (Flash) Floods

    Science.gov (United States)

    Brauer, C.; Teuling, R.; Torfs, P.; Hobbelt, L.; Jansen, F.; Melsen, L.; Uijlenhoet, R.

    2012-12-01

    On 26 August 2010 the eastern part of The Netherlands and the bordering part of Germany were struck by a series of rainfall events. Over an area of 740 km2 more than 120 mm of rainfall were observed in 24 h. We investigated the unprecedented flash flood triggered by this exceptionally heavy rainfall event (return period > 1000 years) in the 6.5 km2 Hupsel Brook catchment, which has been the experimental watershed employed by Wageningen University since the 1960s. This study improved our understanding of the dynamics of such lowland flash floods (Brauer et al., 2011). These observations, however, only show how our experimental catchment behaved and the results cannot be extrapolated directly to different floods in other (neighboring) lowland catchments. Therefore, it is necessary to use the information collected in one well-monitored catchment in combination with data from other, less well monitored catchments to find common signatures which could describe the runoff response during a lowland flood as a function of catchment characteristics. Because of the large spatial extent of the rainfall event in August 2010, many brooks and rivers in the Netherlands and Germany flooded. With data from several catchments we investigated the influence of rainfall and catchment characteristics (such as slope, size and land use) on the reaction of discharge to rainfall. We also investigated the runoff response in these catchments during previous floods by analyzing the relation between storage and discharge and the recession curve. In addition to the flood in August 2010, two other floods occurred in The Netherlands in recently. The three floods occurred in different parts of the country, after different types of rainfall events and with different initial conditions. We selected several catchments during each flood to compare their response and find out if these cases are fundamentally different or that they were produced by the same underlying processes and can be treated in a

  5. 浅析OpenFlashChart的使用%Brief Introduction Usage of Open Flash Chart

    Institute of Scientific and Technical Information of China (English)

    周伟伟; 童敏娟

    2012-01-01

    Open Flash Chart是基于Web网络应用图表技术,用简单方便配置提供出绚丽动画效果,并且图表类型丰富多彩、数据文件结构清晰而明了.通过Open Flash Chart可以生成线图、饼状图、柱状图、雷达图、区域图以及组合图表等.设定颜色、字体、背景等CSS样式,为用户提供了大量可选择的数据图表显示方式.

  6. Article coated with flash bonded superhydrophobic particles

    Science.gov (United States)

    Simpson, John T [Clinton, TN; Blue, Craig A [Knoxville, TN; Kiggans, Jr., James O [Oak Ridge, TN

    2010-07-13

    A method of making article having a superhydrophobic surface includes: providing a solid body defining at least one surface; applying to the surface a plurality of diatomaceous earth particles and/or particles characterized by particle sizes ranging from at least 100 nm to about 10 .mu.m, the particles being further characterized by a plurality of nanopores, wherein at least some of the nanopores provide flow through porosity, the particles being further characterized by a plurality of spaced apart nanostructured features that include a contiguous, protrusive material; flash bonding the particles to the surface so that the particles are adherently bonded to the surface; and applying a hydrophobic coating layer to the surface and the particles so that the hydrophobic coating layer conforms to the nanostructured features.

  7. A new French flash flood warning service

    Directory of Open Access Journals (Sweden)

    de Saint-Aubin Céline

    2016-01-01

    Full Text Available The French State services in charge of flood forecasting supervise about 22,000 km among the 120,000 km of the French rivers within a warning procedure called Vigilance Crues (http://www.vigicrues.gouv.fr. Some recent dramatic flood events on small watershed not covered by Vigilance Crues highlight the need for a new warning procedure to anticipate violent flash floods that regularly affect rapid river-basins. Thus the concept emerged of an automatic warning service specifically dedicated to local crisis managers. This service will be less elaborated than Vigilance Crues, probably with false alarms and missed events sometimes, but it will deliver a first information. The generation of the warning is based on a simple rainfall-runoff hydrological model developed by Irstea on all French rivers, fed with radar-gauge rainfall grids provided by Meteo-France. Every fifteen minutes, the hydrological model estimates the discharges on the rivers eligible to the service and determine if certain thresholds corresponding to a high or very high flood are likely to be exceeded. The last step of the real-time system is to determine which municipalities are concerned with flood risk and send them an automatic warning by voice call, optionally by sms or email. A specific web interface is available for users to monitor the evolution of the flood risk on maps that are updated every 15 minutes. This new flash flood warning service will be operational early 2017 as a free service for about 8,000 French municipalities.

  8. Storage Coding for Wear Leveling in Flash Memories

    CERN Document Server

    Anxiao,; Mateescu, Robert; Yaakobi, Eitan; Bruck, Jehoshua; Siegel, Paul H; Vardy, Alexander; Wolf, Jack K

    2009-01-01

    Flash memory is a non-volatile computer memory comprised of blocks of cells, wherein each cell is implemented as either NAND or NOR floating gate. NAND flash is currently the most widely used type of flash memory. In a NAND flash memory, every block of cells consists of numerous pages; rewriting even a single page requires the whole block to be erased and reprogrammed. Block erasures determine both the longevity and the efficiency of a flash memory. Therefore, when data in a NAND flash memory are reorganized, minimizing the total number of block erasures required to achieve the desired data movement is an important goal. This leads to the flash data movement problem studied in this paper. We show that coding can significantly reduce the number of block erasures required for data movement, and present several optimal or nearly optimal data-movement algorithms based upon ideas from coding theory and combinatorics. In particular, we show that the sorting-based (non-coding) schemes require at least O(nlogn) erasu...

  9. Simulated CONUS Flash Flood Climatologies from Distributed Hydrologic Models

    Science.gov (United States)

    Flamig, Z.; Gourley, J. J.; Vergara, H. J.; Kirstetter, P. E.; Hong, Y.

    2016-12-01

    This study will describe a CONUS flash flood climatology created over the period from 2002 through 2011. The MRMS reanalysis precipitation dataset was used as forcing into the Ensemble Framework For Flash Flood Forecasting (EF5). This high resolution 1-sq km 5-minute dataset is ideal for simulating flash floods with a distributed hydrologic model. EF5 features multiple water balance components including SAC-SMA, CREST, and a hydrophobic model all coupled with kinematic wave routing. The EF5/SAC-SMA and EF5/CREST water balance schemes were used for the creation of dual flash flood climatologies based on the differing water balance principles. For the period from 2002 through 2011 the daily maximum streamflow, unit streamflow, and time of peak streamflow was stored along with the minimum soil moisture. These variables are used to describe the states of the soils right before a flash flood event and the peak streamflow that was simulated during the flash flood event. The results will be shown, compared and contrasted. The resulting model simulations will be verified on basins less than 1,000-sq km with USGS gauges to ensure the distributed hydrologic models are reliable. The results will also be compared spatially to Storm Data flash flood event observations to judge the degree of agreement between the simulated climatologies and observations.

  10. Flash-sourcing or the rapid detection and characterisation of earthquake effects through clickstream data analysis

    Science.gov (United States)

    Bossu, R.; Mazet-Roux, G.; Roussel, F.; Frobert, L.

    2011-12-01

    Rapid characterisation of earthquake effects is essential for a timely and appropriate response in favour of victims and/or of eyewitnesses. In case of damaging earthquakes, any field observations that can fill the information gap characterising their immediate aftermath can contribute to more efficient rescue operations. This paper presents the last developments of a method called "flash-sourcing" addressing these issues. It relies on eyewitnesses, the first informed and the first concerned by an earthquake occurrence. More precisely, their use of the EMSC earthquake information website (www.emsc-csem.org) is analysed in real time to map the area where the earthquake was felt and identify, at least under certain circumstances zones of widespread damage. The approach is based on the natural and immediate convergence of eyewitnesses on the website who rush to the Internet to investigate cause of the shaking they just felt causing our traffic to increase The area where an earthquake was felt is mapped simply by locating Internet Protocol (IP) addresses during traffic surges. In addition, the presence of eyewitnesses browsing our website within minutes of an earthquake occurrence excludes the possibility of widespread damage in the localities they originate from: in case of severe damage, the networks would be down. The validity of the information derived from this clickstream analysis is confirmed by comparisons with EMS98 macroseismic map obtained from online questionnaires. The name of this approach, "flash-sourcing", is a combination of "flash-crowd" and "crowdsourcing" intending to reflect the rapidity of the data collation from the public. For computer scientists, a flash-crowd names a traffic surge on a website. Crowdsourcing means work being done by a "crowd" of people; It also characterises Internet and mobile applications collecting information from the public such as online macroseismic questionnaires. Like crowdsourcing techniques, flash-sourcing is a

  11. Flash ionization signature in coherent cyclotron emission from brown dwarfs

    Science.gov (United States)

    Vorgul, I.; Helling, Ch.

    2016-05-01

    Brown dwarfs (BDs) form mineral clouds in their atmospheres, where charged particles can produce large-scale discharges in the form of lightning resulting in substantial sudden increase of local ionization. BDs are observed to emit cyclotron radio emission. We show that signatures of strong transient atmospheric ionization events (flash ionization) can be imprinted on a pre-existing radiation. Detection of such flash ionization events will open investigations into the ionization state and atmospheric dynamics. Such events can also result from explosion shock waves, material outbursts or (volcanic) eruptions. We present an analytical model that describes the modulation of a pre-existing electromagnetic radiation by a time-dependent (flash) conductivity that is characteristic for flash ionization events like lightning. Our conductivity model reproduces the conductivity function derived from observations of terrestrial gamma-ray flashes, and is applicable to astrophysical objects with strong temporal variations in the local ionization, as in planetary atmospheres and protoplanetary discs. We show that the field responds with a characteristic flash-shaped pulse to a conductivity flash of intermediate intensity. More powerful ionization events result in smaller variations of the initial radiation, or in its damping. We show that the characteristic damping of the response field for high-power initial radiation carries information about the ionization flash magnitude and duration. The duration of the pulse amplification or the damping is consistently shorter for larger conductivity variations and can be used to evaluate the intensity of the flash ionization. Our work suggests that cyclotron emission could be probe signals for electrification processes inside BD atmosphere.

  12. Weak positive cloud-to-ground flashes in Northeastern Colorado

    Science.gov (United States)

    Lopez, Raul E.; Maier, Michael W.; Garcia-Miguel, Juan A.; Holle, Ronald L.

    1991-01-01

    The frequency distributions of the peak magnetic field associated with the first detected return stroke of positive and negative cloud-to-ground (CG) flashes were studied using lightning data from northeastern Colorado. These data were obtained during 1985 with a medium-to-high gain network of three direction finders (DF's). The median signal strength of positive flashes was almost two times that of the negatives for flashes within 300 km of the DF's, which have an inherent detection-threshold bias that tends to discriminate against weak signals. This bias increases with range, and affects the detection of positive and negative flashes in different ways, because of the differing character of their distributions. Positive flashes appear to have a large percentage of signals clustered around very weak values that are lost to the medium-to-high gain Colorado Detection System very quickly with increasing range. The resulting median for positive signals could thus appear to be much larger than the median for negative signals, which are more clustered around intermediate values. When only flashes very close to the DF's are considered, however, the two distributions have almost identical medians. The large percentage of weak positive signals detected close to the DF's has not been explored previously. They have been suggested to come from intracloud discharges and thus are improperly classified as CG flashes. Evidence in hand, points to their being real positive, albeit weak CG flashes. Whether or not they are real positive ground flashes, it is important to be aware of their presence in data from magnetic DF networks.

  13. Gamma ray flashes add to mystery of upper atmosphere

    Science.gov (United States)

    Atmospheric electricity research has come a long way since Benjamin Franklin's kite-flying days. But what researchers have been learning lately about above-thunderstorm electricity has wrought a whole new era of mysteries.For a start, last summer a Colorado meteorologist sparked interest in a terrestrial phenomenon that the community first observed more than 100 years ago: optical flashes that occur above thunderstorms—at least 30 km above Earth. Walter Lyons with the Ft. Collins-based Mission Research Corporation, demonstrated that such flashes are not anomalies, as conventional scientific wisdom had held. He filmed hundreds of flashes during a 2-week period.

  14. FLASH is an essential component of Cajal bodies.

    Science.gov (United States)

    Barcaroli, D; Dinsdale, D; Neale, M H; Bongiorno-Borbone, L; Ranalli, M; Munarriz, E; Sayan, A E; McWilliam, J M; Smith, T M; Fava, E; Knight, R A; Melino, G; De Laurenzi, V

    2006-10-03

    Cajal bodies are small nuclear organelles with a number of nuclear functions. Here we show that FLICE-associated huge protein (FLASH), originally described as a component of the apoptosis signaling pathway, is mainly localized in Cajal bodies and is essential for their structure. Reduction in FLASH expression by short hairpin RNA results in disruption of the normal architecture of the Cajal body and relocalization of its components. Because the function of FLASH in the apoptosis receptor signaling pathway has been strongly questioned, we have now identified a clear function for this protein.

  15. FLASH-OFDM-通信业的新宠

    Institute of Scientific and Technical Information of China (English)

    李勇民

    2008-01-01

    OFDM技术是宽带无线接(BWA)领域内的一种重要技术,本文从介绍OFDM原理入手,突出了它抗干扰能力强、频谱利用率高等特点,而FLASH-OFDM则是OFDM技术中的一种.之后进一步介绍了FLASH-OFDM技术的协议模型,对物理层、MAC/路层和网络层进行了详细的介绍,从而得到了FLASH-OFDM技术的优越性.

  16. Oxygen isotope fractionation during spin-forbidden photolysis of CO2: Relevance to the atmosphere of Mars

    Science.gov (United States)

    Lyons, J. R.; Stark, G.; Pack, A.; de Oliveira, N.; Nahon, L.

    2015-12-01

    The oxygen isotope composition of the Martian atmosphere is of interest for comparison with recent MSL SAM results, and to understand the origin of oxygen isotope anomalies (i.e., mass-independent fractionation or MIF) in secondary minerals in SNC meteorites. Our focus here is on spin-forbidden photolysis of CO2, CO2 + hv (>167 nm) → CO(X1S) + O(3P). The spin-forbidden photolysis of CO2 is unusual in the Martian atmosphere because of its high reaction rate from the upper atmosphere (80 km) all the way to the ground. This range of altitudes spans 4 orders of magnitude in atmospheric pressure, and occurs because of the gradual decrease in the CO2 cross sections from 167 to ~200 nm. Previous laboratory photolysis experiments on CO2 in the spin-allowed and spin-forbidden regions have yielded a remarkably large MIF signature (17O excess ~ 100 permil) in O2 product for photolysis at 185 nm. Recent theoretical cross sections for CO2 isotopologues argue for a much smaller MIF signature from spin-forbidden photolysis. Here, we report the results of photolysis experiments on CO2 at the Soleil synchrotron DESIRS beamline. High purity, natural isotope abundance CO2 was placed in a 20 cm photocell with MgF2 windows. Experiments were performed at 3 wavelengths (7% FWHM): 160 nm (spin-allowed), and at 175 nm and 185 nm (spin-forbidden). After VUV exposure, aliquots of the photolyzed CO2 were sent to the Department of Isotope Geology at the University of Goettingen for O isotope analysis. The isotope results show that the spin-allowed photolysis yields normal, mass-dependent fractionation in agreement with earlier work. Photolysis at 175 nm, which is mostly spin-forbidden, yields a small positive (or zero) MIF signature. Photolysis at 185 nm, which is entirely spin-forbidden, yields O2 with a negative MIF signature (D17O ~ -8 to -10 permil). The results at 185 nm disagree in magnitude and sign with the very large positive MIF signature previously reported, and provides support

  17. Model-aided radiometric determination of photolysis frequencies in a sunlit atmosphere simulation chamber

    Directory of Open Access Journals (Sweden)

    B. Bohn

    2004-10-01

    Full Text Available In this work diurnal and seasonal variations of mean photolysis frequencies for the atmosphere simulation chamber SAPHIR at Forschungszentrum Jülich are calculated. SAPHIR has a complex construction with UV permeable teflon walls allowing natural sunlight to enter the reactor volume. The calculations are based on external measurements of solar spectral actinic flux and a model considering the time-dependent impact of shadows from construction elements as well as the influence of the teflon walls. Overcast and clear-sky conditions are treated in a consistent way and different assumptions concerning diffuse sky radiance distributions are tested. Radiometric measurements inside the chamber are used for an inspection of model predictions. Under overcast conditions we obtain 74% and 67% of external values for photolysis frequencies j(NO2 (NO2+hν→NO+O(3P and j(O1D (O3+hν→O2+O(1D, respectively. On a clear sky summer day these values are time-dependent within ranges 0.65–0.86 and 0.60–0.73, for j(NO2 and j(O1D, respectively. A succeeding paper (Bohn et al., 2004 is dealing with an on-road test of the model approach by comparison with photolysis frequencies from chemical actinometry experiments within SAPHIR.

  18. Absolute absorption cross-section and photolysis rate of I2

    Directory of Open Access Journals (Sweden)

    J. M. C. Plane

    2004-05-01

    Full Text Available Following recent observations of molecular iodine (I2 in the coastal marine boundary layer (MBL (Saiz-Lopez and Plane, 2004, it has become important to determine the absolute absorption cross-section of I2 at reasonably high resolution, and also to evaluate the rate of photolysis of the molecule in the lower atmosphere. The absolute absorption cross-section (σ of gaseous I2 at room temperature and pressure (295 K, 760 Torr was therefore measured between 182 and 750 nm using a Fourier Transform spectrometer at a resolution of 4 cm−1 (0.1 nm at λ=500 nm. The maximum absorption cross-section in the visible region was observed at λ=533.0 nm to be σ=(4.84±0.60×10−18cm2 molecule−1. The spectrum is available as supplementary material accompanying this paper. The photo-dissociation rate constant (J of gaseous I2 was also measured directly in a solar simulator, yielding J(I2=0.12±0.03 s−1 for the lower troposphere. This agrees well with the value of 0.15±0.03 s−1 calculated using the measured absorption cross-section, terrestrial solar flux for clear sky conditions and assuming a photo-dissociation yield of unity. A two-stream radiation transfer model was then used to determine the variation in photolysis rate with solar zenith angle (SZA, from which an analytic expression is derived for use in atmospheric models. Photolysis appears to be the dominant loss process for I2 during daytime, and hence an important source of iodine atoms in the lower atmosphere.

  19. Chlorine-catalyzed ozone destruction: Cl atom production from ClOOCl photolysis.

    Science.gov (United States)

    Wilmouth, David M; Hanisco, Thomas F; Stimpfle, Richard M; Anderson, James G

    2009-12-24

    Recent laboratory measurements of the absorption cross sections of the ClO dimer, ClOOCl, have called into question the validity of the mechanism that describes the catalytic removal of ozone by chlorine. Here we describe direct measurements of the rate-determining step of that mechanism, the production of Cl atoms from the photolysis of ClOOCl, under laboratory conditions similar to those in the stratosphere. ClOOCl is formed in a cold-temperature flowing system, with production initiated by a microwave discharge of Cl(2) or photolysis of CF(2)Cl(2). Excimer lasers operating at 248, 308, and 352 nm photodissociate ClOOCl, and the Cl atoms produced are detected with time-resolved atomic resonance fluorescence. Cl(2), the primary contaminant, is measured directly for the first time in a ClOOCl cross section experiment. We find the product of the quantum yield of the Cl atom production channel of ClOOCl photolysis and the ClOOCl absorption cross section, (phisigma)(ClOOCl) = 660 +/- 100 at 248 nm, 39.3 +/- 4.9 at 308 nm, and 8.6 +/- 1.2 at 352 nm (units of 10(-20) cm(2) molecule(-1)). The data set includes 468 total cross section measurements over a wide range of experimental conditions, significantly reducing the possibility of a systematic error impacting the results. These new measurements demonstrate that long-wavelength photons (lambda = 352 nm) are absorbed by ClOOCl directly, producing Cl atoms with a probability commensurate with the observed rate of ozone destruction in the atmosphere.

  20. Degradation pathways of lamotrigine under advanced treatment by direct UV photolysis, hydroxyl radicals, and ozone.

    Science.gov (United States)

    Keen, Olya S; Ferrer, Imma; Michael Thurman, E; Linden, Karl G

    2014-12-01

    Lamotrigine is recently recognized as a persistent pharmaceutical in the water environment and wastewater effluents. Its degradation was studied under UV and ozone advanced oxidation treatments with reaction kinetics of lamotrigine with ozone (≈4 M(-1)s(-1)), hydroxyl radical [(2.1 ± 0.3) × 10(9)M(-1)s(-1)] and by UV photolysis with low and medium pressure mercury vapor lamps [quantum yields ≈0 and (2.7 ± 0.4)× 10(-4) respectively] determined. All constants were measured at pH 6 and at temperature ≈20°C. The results indicate that lamotrigine is slow to respond to direct photolysis or oxidation by ozone and no attenuation of the contaminant is expected in UV or ozone disinfection applications. The compound reacts rapidly with hydroxyl radicals indicating that advanced oxidation processes would be effective for its treatment. Degradation products were identified under each treatment process using accurate mass time-of-flight spectrometry and pathways of decay were proposed. The main transformation pathways in each process were: dechlorination of the benzene ring during direct photolysis; hydroxyl group addition to the benzene ring during the reaction with hydroxyl radicals; and triazine ring opening after reaction with ozone. Different products that form in each process may be to a varying degree less environmentally stable than the parent lamotrigine. In addition, a novel method of ozone quenching without addition of salts is presented. The new quenching method would allow subsequent mass spectrometry analysis without a solid phase extraction clean-up step. The method involves raising the pH of the sample to approximately 10 for a few seconds and lowering it back and is therefore limited to applications for which temporary pH change is not expected to affect the outcome of the analysis.

  1. Hydrolysis and Photolysis of Herbicide Clomazone in Aqueous Solutions and Natural Water Under Abiotic Conditions

    Institute of Scientific and Technical Information of China (English)

    CAO Jia; DIAO Xiao-ping; HU Ji-ye

    2013-01-01

    The hydrolysis and photolysis of clomazone in aqueous solutions and natural water were assessed under natural and controlled conditions. Kinetics of hydrolysis and photolysis of clomazone were determined by HPLC-DAD. Photoproducts were identiifed by HPLC-MS. No noticeable hydrolysis occurred in aqueous buffer solutions ((25±2)°C, pH (4.5±0.1), pH (7.4±0.1), pH (9.0±0.1);(50±2)°C, pH (4.5±0.1), pH (7.4±0.1)) or in natural water up to 90 d. At pH (9.0±0.1) and (50±2)°C the half-life of clomazone was 50.2 d. Clomazone photodecomposition rate in aqueous solutions under UV radiation and natural sunlight followed ifrst-order kinetics. Degradation rates were faster under UV light (half-life of 51-59 min) compared to sunlight (half-life of 87-136 d). Under UV light, four major photoproducts were detected and tentatively identiifed according to HPLC-MS spectral information such as 2-chlorobenzamide, N-hydroxy-(2-benzyl)-2-methylpropan-amide, 2-[2-phenol]-4,4-dimethyl-3-isoxazolidinone and 2-[(4,6-dihydroxyl-2-chlorine phenol)]-4,4-dimethyl-3-isoxazolidinone. These results suggested that clomazone photodegradation proceeds via several reaction pathways:1) dehalogenation;2) substitution of chlorine group by hydroxyl;3) cleavage of the side chain. Photosensitizers, such as H2O2 and ribolfavin, could enhance photolysis of clomazone in natural sunlight. In summary, we found that photoreaction is an important dissipation pathway of clomazone in natural water systems.

  2. Method of manufacturing metallic products such as sheet by cold working and flash annealing

    Energy Technology Data Exchange (ETDEWEB)

    Hajaligol, Mohammad R. (Midlothian, VA); Sikka, Vinod K. (Oak Ridge, TN)

    2000-01-01

    A metallic alloy composition is manufactured into products such as press formed or stamped products or rolled products such as sheet, strip, rod, wire or band by one or more cold working steps with intermediate or final flash annealing. The method can include cold rolling an iron, nickel or titanium aluminide alloy and annealing the cold worked product in a furnace by infrared heating. The flash annealing is preferably carried out by rapidly heating the cold worked product to an elevated temperature for less than one minute. The flash annealing is effective to reduce surface hardness of the cold worked product sufficiently to allow further cold working. The product to be cold worked can be prepared by casting the alloy or by a powder metallurgical technique such as tape casting a mixture of metal powder and a binder, roll compacting a mixture of the powder and a binder or plasma spraying the powder onto a substrate. In the case of tape casting or roll compaction, the initial powder product can be heated to a temperature sufficient to remove volatile components. The method can be used to form a cold rolled sheet which is formed into an electrical resistance heating element capable of heating to 900.degree. C. in less than 1 second when a voltage up to 10 volts and up to 6 amps is passed through the heating element.

  3. Method of manufacturing metallic products such as sheet by cold working and flash anealing

    Science.gov (United States)

    Hajaligol, Mohammad R.; Sikka, Vinod K.

    2001-01-01

    A metallic alloy composition is manufactured into products such as press formed or stamped products or rolled products such as sheet, strip, rod, wire or band by one or more cold working steps with intermediate or final flash annealing. The method can include cold rolling an iron, nickel or titanium aluminide alloy and annealing the cold worked product in a furnace by infrared heating. The flash annealing is preferably carried out by rapidly heating the cold worked product to an elevated temperature for less than one minute. The flash annealing is effective to reduce surface hardness of the cold worked product sufficiently to allow further cold working. The product to be cold worked can be prepared by casting the alloy or by a powder metallurgical technique such as tape casting a mixture of metal powder and a binder, roll compacting a mixture of the powder and a binder or plasma spraying the powder onto a substrate. In the case of tape casting or roll compaction, the initial powder product can be heated to a temperature sufficient to remove volatile components. The method can be used to form a cold rolled sheet which is formed into an electrical resistance heating element capable of heating to 900.degree. C. in less than 1 second when a voltage up to 10 volts and up to 6 amps is passed through the heating element.

  4. A Bright Lunar Impact Flash Linked to the Virginid Meteor Complex

    Science.gov (United States)

    Moser, D. E.; Suggs, R. M.; Suggs, R. J.

    2015-01-01

    Since early 2006, NASA's Marshall Space Flight Center (MSFC) has observed over 330 impact flashes on the Moon, produced by meteoroids striking the lunar surface. On 17 March 2013 at 03:50:54.312 UTC, the brightest flash of a 9-year routine observing campaign was observed by two 0.35 m telescopes at MSFC. The camera onboard the Lunar Reconnaissance Orbiter (LRO), a NASA spacecraft mapping the Moon from lunar orbit, discovered the fresh crater associated with this impact [1] approximately 3 km from the location predicted by a newly developed geolocation technique [2]. The meteoroid impactor responsible for this event may have been part of a stream of large particles encountered by the Earth/Moon associated with the Virginid Meteor Complex, as evidenced by a cluster of five fireballs seen in Earth's atmosphere on the same night by the NASA All Sky Fireball Network [3] and the Southern Ontario Meteor Network [4]. Crater size calculations based on assumptions derived from fireball measurements yielded an estimated crater diameter of 10-23 m rim-to-rim using the Holsapple [5] and Gault [6] models, a result consistent with the observed crater measured to be 18 m across. This is the first time a lunar impact flash has been associated with fireballs in Earth's atmosphere and an observed crater.

  5. Dynamic Critical Rainfall-Based Flash Flood Early Warning and Forecasting for Medium-Small Rivers

    Science.gov (United States)

    Liu, Z.; Yang, D.; Hu, J.

    2012-04-01

    China is extremely frequent food disasters hit countries, annual flood season flash floods triggered by rainfall, mudslides, landslides have caused heavy casualties and property losses, not only serious threaten the lives of the masses, but the majority of seriously restricting the mountain hill areas of economic and social development and the people become rich, of building a moderately prosperous society goals. In the next few years, China will focus on prevention and control area in the flash flood disasters initially built "for the surveillance, communications, forecasting, early warning and other non-engineering measure based, non-engineering measures and the combinations of engineering measures," the mitigation system. The latest progresses on global torrential flood early warning and forecasting techniques are reviewed in this paper, and then an early warning and forecasting approach is proposed on the basis of a distributed hydrological model according to dynamic critical rainfall index. This approach has been applied in Suichuanjiang River basin in Jiangxi province, which is expected to provide valuable reference for building a national flash flood early warning and forecasting system as well as control of such flooding.

  6. Brominated 7-hydroxycoumarin-4-ylmethyls: Photolabile protecting groups with biologically useful cross-sections for two photon photolysis

    Science.gov (United States)

    Furuta, Toshiaki; Wang, Samuel S.-H.; Dantzker, Jami L.; Dore, Timothy M.; Bybee, Wendy J.; Callaway, Edward M.; Denk, Winfried; Tsien, Roger Y.

    1999-01-01

    Photochemical release (uncaging) of bioactive messengers with three-dimensional spatial resolution in light-scattering media would be greatly facilitated if the photolysis could be powered by pairs of IR photons rather than the customary single UV photons. The quadratic dependence on light intensity would confine the photolysis to the focus point of the laser, and the longer wavelengths would be much less affected by scattering. However, previous caged messengers have had very small cross sections for two-photon excitation in the IR region. We now show that brominated 7-hydroxycoumarin-4-ylmethyl esters and carbamates efficiently release carboxylates and amines on photolysis, with one- and two-photon cross sections up to one or two orders of magnitude better than previously available. These advantages are demonstrated on neurons in brain slices from rat cortex and hippocampus excited by glutamate uncaged from N-(6-bromo-7-hydroxycoumarin-4-ylmethoxycarbonyl)-l-glutamate (Bhc-glu). Conventional UV photolysis of Bhc-glu requires less than one-fifth the intensities needed by one of the best previous caged glutamates, γ-(α-carboxy-2-nitrobenzyl)-l-glutamate (CNB-glu). Two-photon photolysis with raster-scanned femtosecond IR pulses gives the first three-dimensionally resolved maps of the glutamate sensitivity of neurons in intact slices. Bhc-glu and analogs should allow more efficient and three-dimensionally localized uncaging and photocleavage, not only in cell biology and neurobiology but also in many technological applications. PMID:9990000

  7. Laboratory study of nitrate photolysis in Antarctic snow. II. Isotopic effects and wavelength dependence.

    Science.gov (United States)

    Berhanu, Tesfaye A; Meusinger, Carl; Erbland, Joseph; Jost, Rémy; Bhattacharya, S K; Johnson, Matthew S; Savarino, Joël

    2014-06-28

    Atmospheric nitrate is preserved in Antarctic snow firn and ice. However, at low snow accumulation sites, post-depositional processes induced by sunlight obscure its interpretation. The goal of these studies (see also Paper I by Meusinger et al. ["Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry," J. Chem. Phys. 140, 244305 (2014)]) is to characterize nitrate photochemistry and improve the interpretation of the nitrate ice core record. Naturally occurring stable isotopes in nitrate ((15)N, (17)O, and (18)O) provide additional information concerning post-depositional processes. Here, we present results from studies of the wavelength-dependent isotope effects from photolysis of nitrate in a matrix of natural snow. Snow from Dome C, Antarctica was irradiated in selected wavelength regions using a Xe UV lamp and filters. The irradiated snow was sampled and analyzed for nitrate concentration and isotopic composition (δ(15)N, δ(18)O, and Δ(17)O). From these measurements an average photolytic isotopic fractionation of (15)ɛ = (-15 ± 1.2)‰ was found for broadband Xe lamp photolysis. These results are due in part to excitation of the intense absorption band of nitrate around 200 nm in addition to the weaker band centered at 305 nm followed by photodissociation. An experiment with a filter blocking wavelengths shorter than 320 nm, approximating the actinic flux spectrum at Dome C, yielded a photolytic isotopic fractionation of (15)ɛ = (-47.9 ± 6.8)‰, in good agreement with fractionations determined by previous studies for the East Antarctic Plateau which range from -40 to -74.3‰. We describe a new semi-empirical zero point energy shift model used to derive the absorption cross sections of (14)NO3 (-) and (15)NO3 (-) in snow at a chosen temperature. The nitrogen isotopic fractionations obtained by applying this model under the experimental temperature as well as considering the

  8. Laboratory study of nitrate photolysis in Antarctic snow. II. Isotopic effects and wavelength dependence

    Science.gov (United States)

    Berhanu, Tesfaye A.; Meusinger, Carl; Erbland, Joseph; Jost, Rémy; Bhattacharya, S. K.; Johnson, Matthew S.; Savarino, Joël

    2014-06-01

    Atmospheric nitrate is preserved in Antarctic snow firn and ice. However, at low snow accumulation sites, post-depositional processes induced by sunlight obscure its interpretation. The goal of these studies (see also Paper I by Meusinger et al. ["Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry," J. Chem. Phys. 140, 244305 (2014)]) is to characterize nitrate photochemistry and improve the interpretation of the nitrate ice core record. Naturally occurring stable isotopes in nitrate (15N, 17O, and 18O) provide additional information concerning post-depositional processes. Here, we present results from studies of the wavelength-dependent isotope effects from photolysis of nitrate in a matrix of natural snow. Snow from Dome C, Antarctica was irradiated in selected wavelength regions using a Xe UV lamp and filters. The irradiated snow was sampled and analyzed for nitrate concentration and isotopic composition (δ15N, δ18O, and Δ17O). From these measurements an average photolytic isotopic fractionation of 15ɛ = (-15 ± 1.2)‰ was found for broadband Xe lamp photolysis. These results are due in part to excitation of the intense absorption band of nitrate around 200 nm in addition to the weaker band centered at 305 nm followed by photodissociation. An experiment with a filter blocking wavelengths shorter than 320 nm, approximating the actinic flux spectrum at Dome C, yielded a photolytic isotopic fractionation of 15ɛ = (-47.9 ± 6.8)‰, in good agreement with fractionations determined by previous studies for the East Antarctic Plateau which range from -40 to -74.3‰. We describe a new semi-empirical zero point energy shift model used to derive the absorption cross sections of 14NO3- and 15NO3- in snow at a chosen temperature. The nitrogen isotopic fractionations obtained by applying this model under the experimental temperature as well as considering the shift in width and center well

  9. Laboratory study of nitrate photolysis in Antarctic snow. II. Isotopic effects and wavelength dependence

    Energy Technology Data Exchange (ETDEWEB)

    Berhanu, Tesfaye A.; Erbland, Joseph; Savarino, Joël [Laboratoire de Glaciologie et Géophysique de l’Environnement, CNRS, F-38041 Grenoble (France); Univ. Grenoble Alpes, LGGE, F-38041 Grenoble (France); Meusinger, Carl; Johnson, Matthew S. [Copenhagen Center for Atmospheric Research (CCAR), Department of Chemistry, University of Copenhagen, Copenhagen (Denmark); Jost, Rémy [Laboratoire de Interdisciplinaire de Physique (LIPHY) Univ. de Grenoble, Grenoble (France); Bhattacharya, S. K. [Research Center for Environmental Changes, Academia Sinica, Nangang, Taipei 115, Taiwan (China)

    2014-06-28

    Atmospheric nitrate is preserved in Antarctic snow firn and ice. However, at low snow accumulation sites, post-depositional processes induced by sunlight obscure its interpretation. The goal of these studies (see also Paper I by Meusinger et al. [“Laboratory study of nitrate photolysis in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry,” J. Chem. Phys. 140, 244305 (2014)]) is to characterize nitrate photochemistry and improve the interpretation of the nitrate ice core record. Naturally occurring stable isotopes in nitrate ({sup 15}N, {sup 17}O, and {sup 18}O) provide additional information concerning post-depositional processes. Here, we present results from studies of the wavelength-dependent isotope effects from photolysis of nitrate in a matrix of natural snow. Snow from Dome C, Antarctica was irradiated in selected wavelength regions using a Xe UV lamp and filters. The irradiated snow was sampled and analyzed for nitrate concentration and isotopic composition (δ{sup 15}N, δ{sup 18}O, and Δ{sup 17}O). From these measurements an average photolytic isotopic fractionation of {sup 15}ε = (−15 ± 1.2)‰ was found for broadband Xe lamp photolysis. These results are due in part to excitation of the intense absorption band of nitrate around 200 nm in addition to the weaker band centered at 305 nm followed by photodissociation. An experiment with a filter blocking wavelengths shorter than 320 nm, approximating the actinic flux spectrum at Dome C, yielded a photolytic isotopic fractionation of {sup 15}ε = (−47.9 ± 6.8)‰, in good agreement with fractionations determined by previous studies for the East Antarctic Plateau which range from −40 to −74.3‰. We describe a new semi-empirical zero point energy shift model used to derive the absorption cross sections of {sup 14}NO{sub 3}{sup −} and {sup 15}NO{sub 3}{sup −} in snow at a chosen temperature. The nitrogen isotopic fractionations obtained by applying

  10. Degradation of Dissolved Organic Carbon from Discontinuous Permafrost Due to Photolysis and Different Inoculants

    Science.gov (United States)

    Aukes, P.; Schiff, S. L.

    2013-12-01

    Northern areas with permafrost are very susceptible to a warming climate. Temperature increases can alter hydrologic flow paths, increase the depth and biogeochemistry of the active layer, and degrade and reduce the amount of remaining permafrost. Particularly, loss of permafrost will release large stores of previously unavailable frozen carbon to the environment. Dissolved organic carbon (DOC) plays many important roles that affect both ecosystem health and drinking water quality. Comprised of countless different molecules, DOC absorbs harmful ultra-violet (UV) radiation and controls thermal regimes of lakes, is an important energy and nutrient source for heterotrophic microbes, complexes with and transports heavy metals, and reacts during chlorination of drinking water to form carcinogenic disinfection by-products. Since the ultimate fate of DOC depends on its reactivity with the surrounding environment, the implications of DOC released from permafrost for ecosystems and drinking water quality will vary across the landscape. We used 90-day lab incubations to assess the differences in quality of DOC by observing the susceptibility for DOC to degrade among various discontinuous-permafrost sources. Specifically, UV-photolysis and two surface water inoculants (pond and creek water filtered to 2.0μm) were used to represent the dominant degradation pathways encountered within the environment. Samples were taken in July 2013 from three locations (pond, creek, and wetland porewater) in a region of discontinuous permafrost near Yellowknife, NWT, Canada. We observed changes to the composition and quality of DOC resulting from photolysis and degradation by two inoculants over 90 days, where DOC quality was determined by Liquid Chromatography - Organic Carbon Detection, DOC:DON, UV-absorbance, and changes to other constituents (DIC, δ13C-DIC, CO2). We hypothesize that UV-photolysis and microbial degradation will readily degrade easily accessible and reactive components of

  11. Influence of satellite-derived photolysis rates and NOx emissions on Texas ozone modeling

    Directory of Open Access Journals (Sweden)

    W. Tang

    2014-09-01

    Full Text Available Uncertain photolysis rates and emission inventory impair the accuracy of state-level ozone (O3 regulatory modeling. Past studies have separately used satellite-observed clouds to correct the model-predicted photolysis rates, or satellite-constrained top-down NOx emissions to identify and reduce uncertainties in bottom-up NOx emissions. However, the joint application of multiple satellite-derived model inputs to improve O3 State Implementation Plan (SIP modeling has rarely been explored. In this study, Geostationary Operational Environmental Satellite (GOES observations of clouds are applied to derive the photolysis rates, replacing those used in Texas SIP modeling. This changes modeled O3 concentrations by up to 80 ppb and improves O3 simulations by reducing modeled normalized mean bias (NMB and normalized mean error (NME by up to 0.1. A sector-based discrete Kalman filter (DKF inversion approach is incorporated with the Comprehensive Air Quality Model with extensions (CAMx-Decoupled Direct Method (DDM model to adjust Texas NOx emissions using a high resolution Ozone Monitoring Instrument (OMI NO2 product. The discrepancy between OMI and CAMx NO2 vertical column densities (VCD is further reduced by increasing modeled NOx lifetime and adding an artificial amount of NO2 in the upper troposphere. The sector-based DKF inversion tends to scale down area and non-road NOx emissions by 50%, leading to a 2–5 ppb decrease in ground 8 h O3 predictions. Model performance in simulating ground NO2 and O3 are improved using inverted NOx emissions, with 0.25 and 0.04 reductions in NMBs and 0.13 and 0.04 reductions in NMEs, respectively. Using both GOES-derived photolysis rates and OMI-constrained NOx emissions together reduces modeled NMB and NME by 0.05 and increases the model correlation with ground measurement in O3 simulations and makes O3 more sensitive to NOx emissions in the O3 non-attainment areas.

  12. Time-resolved circular dichroism and absorption studies of the photolysis reaction of (carbonmonoxy)myoglobin.

    OpenAIRE

    Milder, S J; Bjorling, S.C.; Kuntz, I D; Kliger, D S

    1988-01-01

    Time-resolved circular dichroism (TRCD) and absorption spectroscopy are used to follow the photolysis reaction of (carbonmonoxy)myoglobin (MbCO). Following the spectral changes associated with the initial loss of CO, a subtle change is observed in the visible absorption spectrum of the Mb product on a time scale of a few hundred nanoseconds. No changes are seen in the CD spectrum of Mb in the visible and near-UV regions subsequent to the loss of CO. The data suggest the existence of an interm...

  13. The challenge of predicting flash floods from thunderstorm rainfall.

    Science.gov (United States)

    Gupta, Hosin; Sorooshian, Soroosh; Gao, Xiaogang; Imam, Bisher; Hsu, Kuo-Lin; Bastidas, Luis; Li, Jailun; Mahani, Shayesteh

    2002-07-15

    A major characteristic of the hydrometeorology of semi-arid regions is the occurrence of intense thunderstorms that develop very rapidly and cause severe flooding. In summer, monsoon air mass is often of subtropical origin and is characterized by convective instability. The existing observational network has major deficiencies for those regions in providing information that is important to run-off generation. Further, because of the complex interactions between the land surface and the atmosphere, mesoscale atmospheric models are currently able to reproduce only general features of the initiation and development of convective systems. In our research, several interrelated components including the use of satellite data to monitor precipitation, data assimilation of a mesoscale regional atmospheric model, modification of the land component of the mesoscale model to better represent the semi-arid region surface processes that control run-off generation, and the use of ensemble forecasting techniques to improve forecasts of precipitation and run-off potential are investigated. This presentation discusses our ongoing research in this area; preliminary results including an investigation related to the unprecedented flash floods that occurred across the Las Vegas valley (Nevada, USA) in July of 1999 are discussed.

  14. Heavy rainfall induced flash flood management

    Science.gov (United States)

    Weiler, Markus; Steinbrich, Andreas; Stölzle, Michael; Leistert, Hannes

    2016-04-01

    Heavy rain induced flash floods are still a serious hazard. In context of climate change even a rise of threat potential of flash flood must be suspected. To improve prediction of endangered areas hydraulic models was developed in the past that implement topography information in heigh resolution, gathered by laser scan applications. To run such models it is crucial to estimate the runoff input spatial distributed. However, this information is usually derived with relatively simple models lacking the process rigour that is required for prediction in engaged basins. Though available rain runoff models are able to model runoff response integral for measured catchments they do not indicate the spatial distribution of processes. Moreover they are commonly calibrated to measured runoff data and not applicable in other environments. Since runoff generation is commonly not measured, a calibration on it is hardly possible. In this study, we present a new approach for quantification of runoff generation in height spatial and temporal resolution. A suited model needs to work without calibration in every given environment under any given conditions. It is possible to develop such a model by combining spatial distributed input data of land surface properties (e.g. soil, geology, land use, …) with worldwide findings of runoff generation research. We developed such a model for the state of Baden-Württemberg, what has an extensive pool of spatial data. E.g. a digital elevation model of 1*1m² resolution, degree of sealing of the earth surface in 1*1m² resolution, soil properties (1:50.000) and geology (1:200.000). Within the state of Baden-Württemberg different regions are situated, with distinct environmental characteristics concerning as well climate, soil properties, land use, topography and geology. The model was tested and validated by modelling 36 observed flood events in 13 mesoscale catchments representing the different regions of Baden-Württemberg as well as by

  15. AIRIX: a new tool for flash radiography in detonics

    Science.gov (United States)

    Cavailler, Claude

    2001-04-01

    AIRIX is an induction linear accelerator which will be used for flash radiography in Commissariat A L'Energie Atomique In France. Designed to produce an X-ray dose of some hundreds Rads at 1 meter with an X-ray focal spot size diameter of less than 2 mm (LANL-CEA DAM definition), this facility consists in a 3,8 MeV/2 kA pulsed electron injector and 15,4 MeV induction accelerator powered by 32 high voltage generators. A prototype of this accelerator, called PIVAIR, has been studied and realized in CEA CESTA near Bordeaux. PIVAIR is a validation step for AIRIX at 8 MeV. It includes an injector (3,6 MeV, 3,2 kA, 60 ns) and 16 induction cells supplied by 8 high voltage generators (250 kV, 70 ns). Two different technologies of induction cells have been tested (Rexolite insulator or ferrite Under Vacuum). We have chosen ferrite under vacuum cells technology after comparison of results on beam transport and reliability tests. A focusing experiment at 7.2 MeV of the electron beam has been achieved during summer 1997. We have begun to produce X-rays in October 1997. A dose level of 50 Rad at 1 meter has been achieved with an X-ray spot size diameter of 3.5 to 4 mm (LANL-CEA DAM definition). Static flash radiography of very dense object have been achieved from November 1997 until February 1998. We have been able to test in situ new kinds of very high sensitive X-ray detectors and to check they had reached our very ambitious goals: quantum efficiency at 5 MeV > 50% instead of 1% for luminous screens and film, sensitivity radiographic luminous screens and films), dynamic range > 100, resolution radiograph of the device explosion under test with the high stopping power detector located in a blast protection set behind the device. In this communication we will present all these techniques which correspond to a significant effort of CEA begun in 1992. AIRIX facility will be available to run detonics experiments before end of 2000.

  16. Microfocusing at the PG1 beamline at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Dziarzhytski, Siarhei, E-mail: siarhei.dziarzhytski@desy.de [DESY, Notkestrasse 85, 22067 Hamburg (Germany); Gerasimova, Natalia [European XFEL GmbH, Albert-Einstein-Ring 19, 22761 Hamburg (Germany); Goderich, Rene [University of South Florida (United States); Mey, Tobias [Laser Laboratorium Göttingen eV, Hans-Adolf-Krebs-Weg 1, 37077 Göttingen (Germany); Reininger, Ruben [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Rübhausen, Michael [University of Hamburg and Center for Free-Electron Laser Science, Notkestrasse 85, 22607 Hamburg (Germany); Siewert, Frank [Institute for Nanometre Optics and Technology at Helmholtz Zentrum Berlin/BESSY II, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Weigelt, Holger; Brenner, Günter [DESY, Notkestrasse 85, 22067 Hamburg (Germany)

    2016-01-01

    The Kirkpatrick–Baez (KB) refocusing mirrors unit at the PG1 beamline at FLASH has been newly designed, developed and fully commissioned. The vertical focal size of the KB optics is measured to be 5.8 ± 1 µm FWHM and the horizontal 6 ± 2 µm FWHM; astigmatism has been minimized to below 1 mm between waist positions. Such a tight focus is essential for the VUV double Raman spectrometer as it serves as an entrance slit for the first monochromator and defines its resolution to a very large extent. The Raman spectrometer is a permanent end-station at the PG1 beamline, dedicated to inelastic soft X-ray scattering experiments. The Kirkpatrick–Baez (KB) refocusing mirror system installed at the PG1 branch of the plane-grating monochromator beamline at the soft X-ray/XUV free-electron laser in Hamburg (FLASH) is designed to provide tight aberration-free focusing down to 4 µm × 6 µm full width at half-maximum (FWHM) on the sample. Such a focal spot size is mandatory to achieve ultimate resolution and to guarantee best performance of the vacuum-ultraviolet (VUV) off-axis parabolic double-monochromator Raman spectrometer permanently installed at the PG1 beamline as an experimental end-station. The vertical beam size on the sample of the Raman spectrometer, which operates without entrance slit, defines and limits the energy resolution of the instrument which has an unprecedented design value of 2 meV for photon energies below 70 eV and about 15 meV for higher energies up to 200 eV. In order to reach the designed focal spot size of 4 µm FWHM (vertically) and to hold the highest spectrometer resolution, special fully motorized in-vacuum manipulators for the KB mirror holders have been developed and the optics have been aligned employing wavefront-sensing techniques as well as ablative imprints analysis. Aberrations like astigmatism were minimized. In this article the design and layout of the KB mirror manipulators, the alignment procedure as well as microfocus

  17. Robust Flash 3D-FPA Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Scientific Concepts, Inc. (ASC) is a small business, which has developed a compact, eye-safe 3D Flash LIDARTM Camera (FLC) well suited for real-time...

  18. Flash3D EDL Sensor Technology Advancement Project

    Data.gov (United States)

    National Aeronautics and Space Administration — 3D Flash LIDAR is ideal for determining real-time spacecraft trajectory, speed, orientation, and range to the planet surface, as well as evaluating potential hazards...

  19. Flash 3D Rendezvous and Docking Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — 3D Flash Ladar is a breakthrough technology for many emerging and existing 3D vision areas, and sensor improvements will have an impact on nearly all these fields....

  20. Space Qualified, Radiation Hardened, Dense Monolithic Flash Memory Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Space Micro proposes to build a radiation hardened by design (RHBD) flash memory, using a modified version of our RH-eDRAM Memory Controller to solve all the single...

  1. The Essential Guide to 3D in Flash

    CERN Document Server

    Olsson, Ronald A

    2010-01-01

    If you are an ActionScript developer or designer and you would like to work with 3D in Flash, this book is for you. You will learn the core Flash 3D concepts, using the open source Away3D engine as a primary tool. Once you have mastered these skills, you will be able to realize the possibilities that the available Flash 3D engines, languages, and technologies have to offer you with Flash and 3D.* Describes 3D concepts in theory and their implementation using Away3D* Dives right in to show readers how to quickly create an interactive, animated 3D scene, and builds on that experience throughout

  2. Photosynthetic efficiency of Chlamydomonas reinhardtii in flashing light

    NARCIS (Netherlands)

    Vejrazka, C.; Janssen, M.G.J.; Streefland, M.; Wijffels, R.H.

    2011-01-01

    Efficient light to biomass conversion in photobioreactors is crucial for economically feasible microalgae production processes. It has been suggested that photosynthesis is enhanced in short light path photobioreactors by mixing-induced flashing light regimes. In this study, photosynthetic efficienc

  3. Quantitative observation of light flash sensations experiment MA-106

    Science.gov (United States)

    Budinger, T. F.; Tobias, C. A.; Schopper, E.; Schott, J. U.; Huesman, R. H.; Upham, F. T.; Wieskamp, T. F.; Kucala, J. M.; Goulding, F. S.; Landis, D. A.

    1976-01-01

    Light flashes caused by the interaction of cosmic particles with the visual apparatus have been observed by astronauts on all space missions since Apollo 11. This Apollo Soyuz Test Project experiment compared measurements of the observer's visual sensitivity with measurements of the ambient radiation environment and with the frequency and character of the flashes observed. The data obtained reveal a latitude dependence of the frequency of observed flashes. This distribution of flashes is correlated with the distribution of cosmic particles with stopping power greater than 15 keV/ micrometers in the eye. The interaction of dark adaptation, specific ionization, and range of particles in the retina as factors in the visualization of particle passage is discussed.

  4. Flash Cracking Reactor for Waste Plastic Processing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to design, model, build, and test a novel flash cracking reactor to convert plastic waste, and potentially other unconventional hydrocarbon feedstocks,...

  5. Impact of rainfall spatial variability on Flash Flood Forecasting

    Science.gov (United States)

    Douinot, Audrey; Roux, Hélène; Garambois, Pierre-André; Larnier, Kevin

    2014-05-01

    According to the United States National Hazard Statistics database, flooding and flash flooding have caused the largest number of deaths of any weather-related phenomenon over the last 30 years (Flash Flood Guidance Improvement Team, 2003). Like the storms that cause them, flash floods are very variable and non-linear phenomena in time and space, with the result that understanding and anticipating flash flood genesis is far from straightforward. In the U.S., the Flash Flood Guidance (FFG) estimates the average number of inches of rainfall for given durations required to produce flash flooding in the indicated county. In Europe, flash flood often occurred on small catchments (approximately 100 km2) and it has been shown that the spatial variability of rainfall has a great impact on the catchment response (Le Lay and Saulnier, 2007). Therefore, in this study, based on the Flash flood Guidance method, rainfall spatial variability information is introduced in the threshold estimation. As for FFG, the threshold is the number of millimeters of rainfall required to produce a discharge higher than the discharge corresponding to the first level (yellow) warning of the French flood warning service (SCHAPI: Service Central d'Hydrométéorologie et d'Appui à la Prévision des Inondations). The indexes δ1 and δ2 of Zoccatelli et al. (2010), based on the spatial moments of catchment rainfall, are used to characterize the rainfall spatial distribution. Rainfall spatial variability impacts on warning threshold and on hydrological processes are then studied. The spatially distributed hydrological model MARINE (Roux et al., 2011), dedicated to flash flood prediction is forced with synthetic rainfall patterns of different spatial distributions. This allows the determination of a warning threshold diagram: knowing the spatial distribution of the rainfall forecast and therefore the 2 indexes δ1 and δ2, the threshold value is read on the diagram. A warning threshold diagram is

  6. Photosynthetic efficiency of Chlamydomonas reinhardtii in flashing light

    NARCIS (Netherlands)

    Vejrazka, C.; Janssen, M.G.J.; Streefland, M.; Wijffels, R.H.

    2011-01-01

    Efficient light to biomass conversion in photobioreactors is crucial for economically feasible microalgae production processes. It has been suggested that photosynthesis is enhanced in short light path photobioreactors by mixing-induced flashing light regimes. In this study, photosynthetic

  7. 3D Flash LIDAR EDL Resolution Improvement Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Scientific Concepts, Inc. (ASC) is a small business, which has developed a compact, eye-safe 3D Flash LIDARTM Camera (FLC) well suited for real-time...

  8. 3D Flash LIDAR Real-Time Embedded Processing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — 3D Flash LIDAR (3DFL) is ideal for determining real-time spacecraft trajectory, speed and orientation to the planet surface, as well as evaluating potential hazards...

  9. Interim report on flash floods, Area 5 - Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    French, R.H.

    1980-09-01

    Examination of the presently available data indicates that consideration must be given to the possibility of flash floods when siting waste management facilities in Area 5 of the Nevada Test Site. 6 figures, 7 tables.

  10. Percepciones sobre seguridad ciudadana en Lima. Encuesta Flash

    OpenAIRE

    Zavaleta Martínez Vargas, Alfonso; Chávez, Virgilio; Tapia, Luis; Vertiz, Rosa

    2016-01-01

    La investigación presenta un aporte relacionado con "consumo de drogas cocaínicas, alcohol y violencia". Resultados de la encuesta flash "Seguridad Ciudadana" realizada por CEDRO en diciembre de 2015.

  11. 3D Flash LIDAR Real-Time Embedded Processing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Scientific Concepts, Inc. (ASC) is a small business, which has developed a compact, eye-safe 3D Flash LIDARTM Camera (FLC) well suited for real-time...

  12. Dynamic simulation of flash drums using rigorous physical property calculations

    Directory of Open Access Journals (Sweden)

    F. M. Gonçalves

    2007-06-01

    Full Text Available The dynamics of flash drums is simulated using a formulation adequate for phase modeling with equations of state (EOS. The energy and mass balances are written as differential equations for the internal energy and the number of moles of each species. The algebraic equations of the model, solved at each time step, are those of a flash with specified internal energy, volume and mole numbers (UVN flash. A new aspect of our dynamic simulations is the use of direct iterations in phase volumes (instead of pressure for solving the algebraic equations. It was also found that an iterative procedure previously suggested in the literature for UVN flashes becomes unreliable close to phase boundaries and a new alternative is proposed. Another unusual aspect of this work is that the model expressions, including the physical properties and their analytical derivatives, were quickly implemented using computer algebra.

  13. Implementing the national AIGA flash flood warning system in France

    Science.gov (United States)

    Organde, Didier; Javelle, Pierre; Demargne, Julie; Arnaud, Patrick; Caseri, Angelica; Fine, Jean-Alain; de Saint Aubin, Céline

    2015-04-01

    The French national hydro-meteorological and flood forecasting centre (SCHAPI) aims to implement a national flash flood warning system to improve flood alerts for small-to-medium (up to 1000 km2) ungauged basins. This system is based on the AIGA method, co-developed by IRSTEA these last 10 years. The method, initially set up for the Mediterranean area, is based on a simple event-based hourly hydrologic distributed model run every 15 minutes (Javelle et al. 2014). The hydrologic model ingests operational radar-gauge rainfall grids from Météo-France at a 1-km² resolution to produce discharges for successive outlets along the river network. Discharges are then compared to regionalized flood quantiles of given return periods and warnings (expressed as the range of the return period estimated in real-time) are provided on a river network map. The main interest of the method is to provide forecasters and emergency services with a synthetic view in real time of the ongoing flood situation, information that is especially critical in ungauged flood prone areas. In its enhanced national version, the hourly event-based distributed model is coupled to a continuous daily rainfall-runoff model which provides baseflow and a soil moisture index (for each 1-km² pixel) at the beginning of the hourly simulation. The rainfall-runoff models were calibrated on a selection of 700 French hydrometric stations with Météo-France radar-gauge reanalysis dataset for the 2002-2006 period. To estimate model parameters for ungauged basins, the 2 hydrologic models were regionalised by testing both regressions (using different catchment attributes, such as catchment area, soil type, and climate characteristic) and spatial proximity techniques (transposing parameters from neighbouring donor catchments), as well as different homogeneous hydrological areas. The most valuable regionalisation method was determined for each model through jack-knife cross-validation. The system performance was then

  14. Tutorial Pengenalan Adobe Photoshop Menggunakan Adobe Flash CS3

    OpenAIRE

    Mayoka, Rio

    2011-01-01

    Kajian ini bertujuan untuk membangun sebuah aplikasi yang dapat menjadi alat bantu dalam pembelajaran Adobe Photoshop, dimana terdapat beberapa materi pengenalan dasar Adobe Photoshop. Aplikasi ini suatu gagasan dengan membuat tutorial beranimasi yang interatif. Aplikasi ini dibuat dengan menggunakan Adobe Flash CS3 dan dapat dijalankan dengan Flash player. Aplikasi ini dapat membantu para penggunanya dalam memahami pengenalan Adobe Photoshop, terutama pengenalan tool pada Adob...

  15. Neural Coding of Green Flash in Retinal Bipolar Pathways

    OpenAIRE

    Caiping Hu

    2012-01-01

    What visual information do the graded potentials among retinal bipolar pathways actually transmit from photoreceptors to ganglion cells? The answer does not exist. Even the graded electric signals have not been understood completely. Here, this paper tries to analyze the encoding mechanisms of graded signals among the parallel bipolar pathways in response to brief green flash. The typical ON, OFF and ON-OFF bipolar cells simultaneously abstracted vectors from green flash stimulus with sine-li...

  16. Flash (Ultra-Rapid) Spark-Plasma Sintering of Silicon Carbide

    OpenAIRE

    Eugene A. Olevsky; Stephen M. Rolfing; Maximenko, Andrey L.

    2016-01-01

    A new ultra-rapid process of flash spark plasma sintering is developed. The idea of flash spark plasma sintering (or flash hot pressing - FHP) stems from the conducted theoretical analysis of the role of thermal runaway phenomena for material processing by flash sintering. The major purpose of the present study is to theoretically analyze the thermal runaway nature of flash sintering and to experimentally address the challenge of uncontrollable thermal conditions by the stabilization of the f...

  17. Photolysis of CF3CH2CHO in the presence of O2 at 248 and 266 nm: quantum yields, products, and mechanism.

    Science.gov (United States)

    Antiñolo, M; Bettinelli, C; Jain, C; Dréan, P; Lemoine, B; Albaladejo, J; Jiménez, E; Fittschen, C

    2013-10-17

    Three different detection techniques, coupled to pulsed laser photolysis (PLP), have been employed to determine the quantum yields of CF3CH2CHO at 248 and 266 nm: CF3CH2CHO + hν → CF3CH2 + HCO (R1a), CF3CH2CHO + hν → CF3CH3 + CO (R1b), and CF3CH2CHO + hν → CF3CH2O + H (R1c). (a) In the presence of air, Fourier transform infrared (FTIR) spectroscopy was employed at a total pressure of 760 Torr to monitor and quantify the loss of CF3CH2CHO at both wavelengths as well as the build-up of formed products (CO, CF3CH3, CF3CHO, and CF3CH2OH) after various laser pulses. Cyclohexane was added as OH-scavenger in most experiments. CF3CH3 was observed and quantified at both wavelengths, confirming that channel R1b is occurring. Small amounts of HCOOH and COF2 were also detected. (b) Time-resolved cw-cavity ring down spectroscopy (cw-CRDS) at 40 Torr He coupled to photolysis at 248 nm was employed for the detection of HO2 radicals. Varying the O2 concentration allows distinguishing the origin of the HO2 radicals from either R1a or R1c. OH radicals were simultaneously detected by laser-induced fluorescence. (c) Time-resolved tunable diode laser absorption spectroscopy (TDLAS) at 30 Torr N2 coupled to photolysis at 266 nm was employed for the determination of the quantum yields of CO. By varying the O2 concentration, a distinction can be achieved between the yields of prompt CO R1b or decomposition of highly excited CF3CH2CO from R1c and HCO radicals R1a. Channel R1a has been identified as the major reaction path. The overall quantum yield, Φλ(CF3CH2CHO), at 248 nm was found as Φ248nm = (0.76 ± 0.14) and (0.73 ± 0.20) from cw-CRDS and FTIR experiments, respectively. At 266 nm, the overall quantum yield was found as Φ266nm = (0.55 ± 0.10) and (0.47 ± 0.10) from TDLAS and FTIR experiments, respectively.

  18. Photolysis pathway of nitroaromatic compounds in aqueous solutions in the UV/H2O2 process

    Institute of Scientific and Technical Information of China (English)

    CHEN Bing; YANG Chun; GOH Ngoh Khang

    2006-01-01

    Nitroaromatic compounds such as nitrobenzene and nitrophenols are largely synthesised and particularly often occur in water bodies as toxic pollutants. The degradation of these compounds in the environment via direct photolysis and by biological treatment is difficult and usually slow. In our two previous published papers, we have discussed the advanced oxidation of nitrobenzene and nitrophenols in aqueous solutions irradiated by direct photolysis using polychromatic light and by means of UV/H2O2 process. The experimental results suggested the UV/H2O2 process is an effective and efficient technology for complete mineralization of these organic compounds. Based on the results therein, comprehensive reaction mechanism for nitrobenzene photolysis was proposed with detailed discussions.

  19. Variations in radiation and photolysis rates in the southern midlatitudes due to ozone depletion over the Antarctica

    Science.gov (United States)

    López Comí, Laura; Morgenstern, Olaf; Zeng, Guang; Masters, Sarah L.

    2013-04-01

    Lauder (45° S, 170° E), a research station located on the South Island of New Zealand, is a clean-air atmospheric observatory representative of southern mid-latitudes. Long-term records of various atmospheric chemical compounds have been measured here for up to three decades. We assess observations of selected atmospheric chemical species, including ozone, and their variability throughout the recording period. By utilizing these observational data and a photolysis scheme (FAST-JX) we will address how changes in the total ozone column and in aerosols at Lauder affect radiation and photolysis rates of different species. The results serve as a stepping stone towards constructing a single-column photolysis model for Lauder constrained with profiles of stable species (e.g. ozone, methane, CO, HCHO, halogen compounds, etc) measured at Lauder to derive variations and trends of shorter-lived species. One of our targets will be changes in the tropospheric oxidizing capacity in the Southern Hemisphere.

  20. Coherence measurements and coherent diffractive imaging at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Vartanyants, I A; Mancuso, A P; Singer, A; Yefanov, O M; Gulden, J, E-mail: ivan.vartaniants@desy.d [Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg (Germany)

    2010-10-14

    We present an overview of recent experiments performed at the free-electron laser (FEL) FLASH at DESY in Hamburg. Experiments were focused on coherence measurements and coherent x-ray diffractive imaging (CXDI) of periodic and non-periodic biological samples. Young's double slit experiment was performed at FLASH to measure its coherence properties at a fundamental wavelength of 13.7 nm. Additionally, a uniformly redundant array was used to measure the coherence properties of the third harmonic (2.7 nm) of an 8 nm fundamental wavelength at FLASH. Coherent imaging of a two-dimensional (2D) finite crystal structure using a single pulse train of FLASH radiation was demonstrated. We show that the structure is reconstructed to the detector-limited resolution of 220 nm, given an adequate signal to noise ratio. We have also employed CXDI in a non-destructive regime to compare the images of a biological sample using single, femtosecond pulses of FLASH radiation. We have verified that images reconstructed using CXDI are similar for statistically different FEL pulses. We have also demonstrated Fourier transform holography of the same biological sample and present diffraction data measured at the third harmonic of FLASH, reaching into the water window.

  1. Establishment of the NIST flashing-light photometric unit

    Science.gov (United States)

    Ohno, Yoshihiro; Zong, Yuqin

    1997-09-01

    There is a need for accurate measurement of flashing lights for the proper maintenance of aircraft anticollision lights. A large variation in the measured intensities of anticollision lights has been a problem, and thus, NIST has undertaken the task to establish flashing-light photometric standards to provide calibration services in this area. A flashing-light photometric unit [lux second, (lx (DOT) s)] has been realized based on the NIST detector-based candela, using four standard photometers equipped with current integrators. Two different approaches have been taken to calibrate these standard photometers: one based on electrical calibration of the current integrator, and the other based on electronic pulsing of a steady-state photometric standard. The units realized using these two independent methods agreed to within 0.2%. The relative expanded uncertainty (k equals 2) of the standard photometers, in the measurement of the white xenon flash, is estimated to be 0.6%. The standard photometers are characterized for temporal response, linearity, and spectral responsivity, to be used for measurement of xenon flash sources of various waveforms and colors. Calibration services have been established at NIST for flashing-light photometers with white and red anticollision lights.

  2. Production of bio-oil with flash pyrolysis; Biooeljyn tuotanto flash-pyrolyysillae ja sen poltto

    Energy Technology Data Exchange (ETDEWEB)

    Nyroenen, T. [Vapo Oy, Jyvaeskylae (Finland)

    1997-12-01

    The target of the R and D work is to study the production of bio-oils using Flash-pyrolysis technology and utilisation of the bio-oil in oil-fuelled boilers. The PDU-unit was installed at VTT Energy in Otaniemi in April 1996. The first test were carried out in June. In the whole project Vapo Oy is responsible for: acquiring the 20 kg/h PDU-device for development; follow up of the engine tests; the investment of 5 MW demonstration plant; to carry on the boiler and engine tests with Finnish bio-oils. (orig.)

  3. Flash lidar performance testing: configuration and results

    Science.gov (United States)

    Poberezhskiy, Ilya; Johnson, Andrew; Chang, Daniel; Ek, Eric; Natzic, David; Spiers, Gary; Penniman, Steve; Short, Brad

    2012-06-01

    Future planetary and lunar landers can benefit from a hazard detection (HD) system that employs a lidar to create a highresolution 3D terrain map in the vicinity of the landing site and an onboard computer to process the lidar data and identify the safest landing site within the surveyed area. A divert maneuver would then be executed to land in this safe site. An HD system enables landing in regions with a relatively high hazard abundance that would otherwise be considered unacceptably risky, but are of high interest to the scientific community. A key component of a HD system is a lidar with the ability to generate a 3D terrain image with the required range precision in the prescribed time and fits within the project resource constraints. In this paper, we present the results obtained during performance testing of a prototype "GoldenEye" 3D flash lidar developed by ASC, Inc. The testing was performed at JPL with the lidar and the targets separated by 200 m. The analysis of the lidar performance obtained for different target types and albedos, pulse energies, and fields of view is presented and compared to key HD lidar requirements identified for the Mars 2018 lander.

  4. Studying white dwarf merger remnants with FLASH

    Science.gov (United States)

    Jenks, Malia

    2017-01-01

    There is still uncertainty as to the progenitor systems of type Ia supernova (SN Ia). Both single and double degenerate systems have been suggested as progenitors. In a double degenerate system a merger between the two white dwarfs, with total mass at or exceeding the Chandrasekhar mass, leads to the supernova. If the explosion occurs during the merging process it is a violent merger. If an explosion doesn't occur while the stars merge the system becomes a white dwarf of unstable mass. For mergers of this type with differing starting masses it has been shown that during the viscous evolution carbon burning starts far from the center and stably converts the star to oxygen and neon. In this case the star will eventually collapse to a neutron star and not produce an SN Ia. The case of similar mass mergers has been much less explored. Using the results of a smooth particle hydrodynamic merger we simulate the viscous evolution of models of different mass ratios with FLASH. These simulations test if a similar mass merger can lead to an SN Ia, and begin to probe where the transition from similar to dissimilar mass occurs.

  5. Flash pyrolysis fuel oil: bio-pok

    Energy Technology Data Exchange (ETDEWEB)

    Gust, S. [Neste Oy, Porvoo (Finland)

    1997-12-01

    Samples of flash pyrolysis liquid produced by Union Fenosa, Spain from pine and straw and samples produced by Ensyn of Canada from mixed hardwoods were combusted with simple pressure atomization equipment commonly used with light fuel oils in intermediate size (0.1-1 MW) boilers. With a number of modifications to the combustion system, carbon monoxide (CO) and nitrous oxide (NO{sub x}) could be reduced to acceptable levels: CO < 30 ppm and NO{sub x} < 140 ppm. Particulate emissions which were initially very high (Bacharach 4-5) were reduced (Bach. 2-3) by system improvements but are still higher than from light fuel oil (Bach. <1). The modifications to the combustion system were: refractory section between burner and boiler, acid resistant progressive cavity pump, higher liquid preheat temperature and higher pressure than for light fuel oils. The main problems with pyrolysis liquids concerns their instability or reactivity. At temperatures above 100 deg C they begin to coke, their viscosity increases during storage and oxygen from air causes skin formation. This requires that special handling procedures are developed for fuel storage, delivery and combustion systems. (orig.)

  6. Photolysis of the antidepressants amisulpride and desipramine in wastewaters: Identification of transformation products formed and their fate

    Energy Technology Data Exchange (ETDEWEB)

    Gros, Meritxell [Commonwealth Scientific and Industrial Research Organization (CSIRO), Land and Water Flagship, Waite Campus, Urrbrae, 5064 Adelaide, SA (Australia); Swedish University of Agricultural Sciences (SLU), Department of Aquatic Sciences and Assessment, Lennart Hjelms väg 9, 75007 Uppsala (Sweden); Williams, Mike, E-mail: Mike.Williams@csiro.au [Commonwealth Scientific and Industrial Research Organization (CSIRO), Land and Water Flagship, Waite Campus, Urrbrae, 5064 Adelaide, SA (Australia); Llorca, Marta; Rodriguez-Mozaz, Sara [Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, C/Emili Grahit, 101 Girona (Spain); Barceló, Damià [Catalan Institute for Water Research (ICRA), Scientific and Technological Park of the University of Girona, C/Emili Grahit, 101 Girona (Spain); Water and Soil Quality Research Group, Department of Environmental IDAEA-CSIC, Jordi Girona 18-26, E-08034 Barcelona (Spain); Kookana, Rai S. [Commonwealth Scientific and Industrial Research Organization (CSIRO), Land and Water Flagship, Waite Campus, Urrbrae, 5064 Adelaide, SA (Australia)

    2015-10-15

    Attenuation of pharmaceuticals due to natural sunlight is expected to be an important removal pathway in wastewater treatment plants using treatment lagoon systems. In this work, the photolysis of two antidepressants, amisulpride and desipramine, has been investigated in both ultrapure water and wastewater under simulated solar irradiation. Results showed that for amisulpride short irradiation times (t{sub 1/2} approximately 3 h in pure water and 4 h in wastewater) were adequate to degrade the parent compound while a longer exposure period was required for desipramine (t{sub 1/2} of approximately 36 h in pure water), although its degradation is enhanced almost three times by indirect photolysis in wastewaters. A significant number of transformation products (TPs) were identified for both pharmaceuticals by high-resolution mass spectrometry. In general, TPs formed are not persistent although acute toxicity tests for desipramine and its TPs showed an increase of the mixture toxicity after solar irradiation, suggesting that some TPs may be more toxic than the parent compound. In wastewaters collected from treatment lagoons, only amisulpride and one of its major TPs, TP 357, were detected. This indicates that long solar exposure times may be necessary for an effective elimination of these substances in lagoon systems or that photolysis may not be the main removal pathway for these particular compounds. - Highlights: • Photolysis of both compounds resulted in several transformation products, some of which were previously unknown. • Short irradiation times may be adequate to degrade amisulpride whereas a longer exposure is required for desipramine. • Transformation of desipramine was enhanced by about three times due to indirect photolysis in wastewaters. • For desipramine, mixture acute toxicity increased after solar irradiation. • Photolysis is unlikely to be the main removal pathway for the two antidepressants during wastewater treatment.

  7. Pressure dependence of the deuterium isotope effect in the photolysis of formaldehyde by ultraviolet light

    Directory of Open Access Journals (Sweden)

    E. J. K. Nilsson

    2010-04-01

    Full Text Available The pressure dependence of the relative photolysis rate of HCHO vs. HCDO has been investigated for the first time, using a photochemical reactor at the University of Copenhagen. The dissociation of HCHO vs. HCDO using a UVA lamp was measured at total bath gas pressures of 50, 200, 400, 600 and 1030 mbar. The products of formaldehyde photodissociation are either H2 + CO (molecular channel or HCO + H (radical channel, and a photolysis lamp was chosen to emit light at wavelengths that greatly favor the molecular channel. The isotope effect in the dissociation, kHCHO/kHCDO, was found to depend strongly on pressure, varying from 1.1 + 0.15/−0.1 at 50 mbar to 1.75±0.10 at 1030 mbar. The results can be corrected for radical channel contribution to yield the kinetic isotope effect for the molecular channel; i.e. the KIE in the production of molecular hydrogen. This is done and the results at 1030 mbar are discussed in relation to previous studies at ambient pressure. In the atmosphere the relative importance of the two product channels changes with altitude as a result of changes in pressure and actinic flux. The study demonstrates that the δD of photochemical hydrogen produced from formaldehyde will increase substantially as pressure decreases.

  8. Photolysis of Caged-GABA Rapidly Terminates Seizures In Vivo: Concentration and Light Intensity Dependence.

    Science.gov (United States)

    Wang, Dan; Yu, Zhixin; Yan, Jiaqing; Xue, Fenqin; Ren, Guoping; Jiang, Chenxi; Wang, Weimin; Piao, Yueshan; Yang, Xiaofeng

    2017-01-01

    The therapy of focal epilepsy remains unsatisfactory for as many as 25% of patients. The photolysis of caged-γ-aminobutyric acid (caged-GABA) represents a novel and alternative option for the treatment of intractable epilepsy. Our previous experimental results have demonstrated that the use of blue light produced by light-emitting diode to uncage ruthenium-bipyridine-triphenylphosphine-c-GABA (RuBi-GABA) can rapidly terminate paroxysmal seizure activity both in vitro and in vivo. However, the optimal concentration of RuBi-GABA, and the intensity of illumination to abort seizures, remains unknown. The aim of this study was to explore the optimal anti-seizure effects of RuBi-GABA by using implantable fibers to introduce blue light into the neocortex of a 4-aminopyridine-induced acute seizure model in rats. We then investigated the effects of different combinations of RuBi-GABA concentrations and light intensity upon seizure. Our results show that the anti-seizure effect of RuBi-GABA has obvious concentration and light intensity dependence. This is the first example of using an implantable device for the photolysis of RuBi-GABA in the therapy of neocortical seizure, and an optimal combination of RuBi-GABA concentration and light intensity was explored. These results provide important experimental data for future clinical translational studies.

  9. Degradation of water polluted with used cooking oil by solar photolysis, Fenton and solar photo Fenton.

    Science.gov (United States)

    Vergara-Sánchez, J; Silva-Martínez, S

    2010-01-01

    The degradation of used cooking safflower oil aqueous solutions by photolysis, Fenton, and photo Fenton under solar light is reported. The processes were carried out in a photochemical reactor with recirculation. Operating variables such as, pH, oil concentration and molar ratio of [H(2)O(2)]:[oil] were investigated to test their effects on the treatment efficiency of Fenton process. Also the iron catalyzed decomposition of hydrogen peroxide in the solar photo Fenton reaction was studied under different experimental conditions. The degree of oil oxidation was monitored by the measurements of chemical oxygen demand (COD) analyses. It was found that at pH 2.6 and a molar ratio of [H(2)O(2)]:[oil] of 489:1 were more efficient for COD abatement. The experimental results showed that the sole effect of the solar irradiation (photolysis) aided to decrease approximately 65% of COD at neutral pH in a reaction time period of 15 h; whereas a decrease of 47% and approximately 90% of COD was obtained by Fenton and photo Fenton treatment, respectively, after a reaction time of 50 min. It was observed a decrease in the decomposition of H(2)O(2) in the solar photo Fenton process, in subsequent additions of H(2)O(2), and H(2)O(2) + Fe(2+).

  10. UV photolysis of diclofenac in water; kinetics, degradation pathway and environmental aspects.

    Science.gov (United States)

    Kovacic, Marin; Juretic Perisic, Daria; Biosic, Martina; Kusic, Hrvoje; Babic, Sandra; Loncaric Bozic, Ana

    2016-08-01

    In this study, the photolysis behavior of commonly used anti-inflammatory drug diclofenac (DCF) was investigated using UV-C and UV-A irradiation. In that purpose, DCF conversion kinetics, mineralization of organic content, biodegradability, and toxicity were monitored and compared. The results showed different kinetics of DCF conversion regarding the type of UV source applied. However, in both cases, the mineralization extent reached upon complete DCF conversion is rather low (≤10 %), suggesting that the majority of DCF was transformed into by-products. Formation/degradation of main degradation by-products was monitored using high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS), whereas different profiles were obtained by UV-C and UV-A photolysis. The results of bioassays revealed that biodegradability of DCF solutions remained low through the applied treatments. The toxicity of irradiated DCF solutions was evaluated using Vibrio fischeri. A significant reduction of toxicity, especially in the case of UV-A radiation, was observed upon complete degradation of DCF. In addition to toxicity reduction, calculated Log K OW values of DCF degradation by-products indicate their low potential for bioaccumulation (Log K OW ≤ 3) in comparison to the parent substance.

  11. Direct measurements of NO{sub 2} photolysis rates for Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Castro, T.; Ruiz-Suarez, L. G.; Gay, C. [Centro de Ciencias de la Atmosfera, UNAM, Mexico, D.F. (Mexico); Helguera, M. [Centro Nacional de Investigacion y Desarrollo Tecnologico, SEP, Cuernavaca, Mor. (Mexico); Ruiz-Suarez, J. C. [Departamento de Fisica Aplicada, CINVESTAV del IPN, Unidad Merida, Merida, Yucatan, (Mexico)

    1995-07-01

    Direct measurements of the rate of NO{sub 2} photolysis to NO and O({sup 3}P) are reported as photolysis frequencies J (NO{sub 2}) for Mexico City. These frequencies were measured using a flow reactor, where a known concentration of NO{sub 2} was photolysed for different experimental exposure times. Ultraviolet (UV) radiation was measured with an Eppley UV radiometer. Comparisons with calculated values using a radiation transfer model, and Madronich's formula are shown. [Spanish] Se reportan medidas de las constantes de fotolisis del NO{sub 2} a NO y O({sup 3}P) como frecuencias de fotolisis J(NO{sub 2}) para la Ciudad de Mexico. Estas frecuencias se midieron usando un reactor, en donde una concentracion conocida de NO{sub 2} se fotodisocia para diferentes tiempos de exposicion. La radiacion ultravioleta (UV) se midio con un radiometro Eppley. Se muestra una comparacion con valores calculados usando un modelo de transferencia y la formula de Madronich.

  12. Photolysis and Fluorescence in the /delta and /epsilon Bands of Thermospheric NO

    Science.gov (United States)

    Yonker, J. D.; Bailey, S. M.; Paxton, L. J.

    2008-12-01

    Recent measurements of the oscillator strengths (Yoshino et al, 2006) and predissociation rates (Luque and Crosley, 2000) for the δ and ɛ band systems of nitric oxide (NO) suggest a reevaluation of the NO photolysis rate. It is well-known that the dominant contribution throughout the atmosphere is due to dissociation in the δ(0,0) and δ (1,0) bands. However, above 90 km, attenuation of the solar VUV irradiance due to the O2 Schumann-Runge system is diminished and the contribution of the δ(2,0), ɛ(1,0), and ɛ(2,0) bands to the photolysis rate becomes increasingly significant. In this talk it is shown that the contribution from these bands rises from 16% at 100km to 26% above 120 km. As the ratio of the radiative to predissociation rates for the δ(0,0), ɛ(0,0), ɛ(1,0), and ɛ(2,0) bands is sensitive to the rotational level, expected fluorescence from these bands is also presented using data from the Student Nitric Oxide Explorer (SNOE).

  13. Photolysis and cellular toxicities of the organic ultraviolet filter chemical octyl methoxycinnamate and its photoproducts.

    Science.gov (United States)

    Stein, Hannah V; Berg, Courtney J; Maung, Jessica N; O'Connor, Lauren E; Pagano, Alexandra E; MacManus-Spencer, Laura A; Paulick, Margot G

    2017-06-21

    Organic ultraviolet filter chemicals (UVFCs) are the active ingredients used in many sunscreens to protect the skin from UV light; these chemicals have been detected in numerous aquatic environments leading to concerns about how they might affect aquatic organisms and humans. One commonly used organic UVFC is octyl methoxycinnamate (OMC), better known by its commercial name, octinoxate. Upon exposure to UV light, OMC degrades rapidly, forming numerous photoproducts, some of which have been previously identified. In this study, we isolated and completely characterized the major products of OMC photolysis, including the two major stable OMC cyclodimers. One of these cyclodimers is a δ-truxinate, resulting from a head-to-head dimerization of two OMC molecules, and the other cyclodimer is an α-truxillate, resulting from a head-to-tail dimerization of two OMC molecules. Additionally, the cellular toxicities of the individual photoproducts were determined; it was found that the parent UVFC, OMC, 4-methoxybenzaldehyde, and two cyclodimers are significantly toxic to cells. The photoproduct 2-ethylhexanol is not cytotoxic, demonstrating that different components of OMC photolysate contribute differently to its cellular toxicity. This study thus provides an enhanced understanding of OMC photolysis and gives toxicity data that can be used to better evaluate OMC as a sunscreen agent.

  14. The effect of hydrogen peroxide and solvent on photolysis of PCBs to reduce occupational exposure

    Directory of Open Access Journals (Sweden)

    Hasan Asilian

    2010-09-01

    Full Text Available Background: Polychlorinated biphenyls (PCBs are toxic bio-accumulate components and may increase risk of adverse effects on human health and the environment. For different social, technical and economic reasons, significant quantities of PCBs contaminated transformer oil are still in use or storied. The study aimed to determine the effect of hydrogen peroxide and solvent on photolysis of PCBs to reduce occupational exposure. Methods: The photochemical annular geometry (500 ml volume reactor was designed with a cylindrical low-pressure mercury lamp (UV-C Cathodeon TUV 6WE with emission at 254 nm. The radiant power emitted by the lamp was 6w. The whole lamp was immersed in a reactor thermostat controlling of temperature at 32 ± 2 oC. The PCBs was determined using GC/ECD and data was analyzed by SPSS. Results: Degradation of total PCBs in terms of %10 and %20 of volume of H2O2 were 41%, 75% and 94%, respectively. The degradation of total PCBs in terms of ratio to solvent with oil transformer in 1:1, 2:1 and 3:1 was 61%, 75% and 94%, respectively. Conclusion: Our study show that UV-C photolysis of H2O2 leads to a degradation efficiency of PCBs only in the presence of isooctane, therefore indicating that the intermediates formation after ethanol oxidation are able to initiate PCBs degradation.

  15. Synergistic effect of proanthocyanidin on the bactericidal action of the photolysis of H2O2.

    Science.gov (United States)

    Ikai, Hiroyo; Nakamura, Keisuke; Kanno, Taro; Shirato, Midori; Meirelles, Luiz; Sasaki, Keiichi; Niwano, Yoshimi

    2013-01-01

    The in vitro antibacterial activity of the hydroxyl radical generation system by the photolysis of H2O2 in combination with proanthocyanidin, which refers to a group of polyphenolic compounds, was examined. Bactericidal activity of photo-irradiated H2O2 at 405 nm against Streptococcus mutans, a major pathogen of dental caries, was augmented in the presence of proanthocyanidin, whose bactericidal effect by itself was very poor, in a concentration-dependent manner. This combination was also proven effective against Porphyromonas gingivalis, a major pathogen of periodontitis. It is speculated that H2O2, generated from photo-irradiated proanthocyanidin around the bacterial cells, is photolyzed to the hydroxyl radical, which would in turn affect the membrane structure and function of the bacterial cells, resulting in augmented sensitivity of bacterial cells to the disinfection system utilizing the photolysis of H2O2. The present study suggests that the combination of H2O2 and proanthocyanidin works synergistically to kill bacteria when photo-irradiated.

  16. Efficiencies and Physical Principles of Various Solar Energy Conversion Processes Leading to the Photolysis of Water

    Energy Technology Data Exchange (ETDEWEB)

    Bergene, T.

    1995-12-31

    In the application of solar energy, hydrogen is likely to be used as an energy carrier and a storage medium. Production of molecular hydrogen and oxygen from water requires energy input, which may come from solar energy in various ways. This thesis begins with a literature survey of the different conversion processes and the efficiencies, which is an introduction to a series of enclosed papers. These papers are: (1) Trapping of Minority Charge Carriers at Irradiated Semiconductor/Electrolyte Heterojunctions, (2) Model Calculations on Flat-Plate Solar Heat Collector With Integrated Solar Cells, and (3) Efficiencies and Physical Principles of Photolysis of Water By Microalgae. In the papers, The qualitative features of the ``illumination-current``-characteristic curve are deduced. The hypothesis is that trapping originates in some specific cases because of confinement, which leads to charge injections into energy states above that corresponding to the band edge. The quantitative features of certain hybrid photovoltaic/thermal configuration are deduced. An analysis of the theoretical and realizable efficiencies of the photolysis of water by micro algae is given. 151 refs., 18 figs., 1 table

  17. Radical-induced chemistry from VUV photolysis of interstellar ice analogues containing formaldehyde

    Science.gov (United States)

    Butscher, Teddy; Duvernay, Fabrice; Danger, Grégoire; Chiavassa, Thierry

    2016-09-01

    Surface processes and radical chemistry within interstellar ices are increasingly suspected to play an important role in the formation of complex organic molecules (COMs) observed in several astrophysical regions and cometary environments. We present new laboratory experiments on the low-temperature solid state formation of complex organic molecules - glycolaldehyde, ethylene glycol, and polyoxymethylene - through radical-induced reactivity from VUV photolysis of formaldehyde in water-free and water-dominated ices. Radical reactivity and endogenous formation of COMs were monitored in situ via infrared spectroscopy in the solid state and post photolysis with temperature programmed desorption (TPD) using a quadripole mass spectrometer. We show the ability of free radicals to be stored when formed at low temperature in water-dominated ices, and to react with other radicals or on double bonds of unsaturated molecules when the temperature increases. It experimentally confirms the role of thermal diffusion in radical reactivity. We propose a new pathway for formaldehyde polymerisation induced by HCO radicals that might explain some observations made by the Ptolemy instrument on board the Rosetta lander Philae. In addition, our results seem to indicate that H-atom additions on H2CO proceed preferentially through CH2OH intermediate radicals rather than the CH3O radical.

  18. Laser Photolysis and Thermolysis of Organic Selenides and Tellurides for Chemical Gas-phase Deposition of Nanostructured Materials

    Directory of Open Access Journals (Sweden)

    Josef Pola

    2009-03-01

    Full Text Available Laser radiation-induced decomposition of gaseous organic selenides and tellurides resulting in chemical deposition of nanostructured materials on cold surfaces is reviewed with regard to the mechanism of the gas-phase decomposition and properties of the deposited materials. The laser photolysis and laser thermolysis of the Se and Te precursors leading to chalcogen deposition can also serve as a useful approach to nanostructured chalcogen composites and IVA group (Si, Ge, Sn element chalcogenides provided that it is carried out simultaneously with laser photolysis or thermolysis of polymer and IVA group element precursor.

  19. Laser photolysis and thermolysis of organic selenides and tellurides for chemical gas-phase deposition of nanostructured materials.

    Science.gov (United States)

    Pola, Josef; Ouchi, Akihiko

    2009-03-12

    Laser radiation-induced decomposition of gaseous organic selenides and tellurides resulting in chemical deposition of nanostructured materials on cold surfaces is reviewed with regard to the mechanism of the gas-phase decomposition and properties of the deposited materials. The laser photolysis and laser thermolysis of the Se and Te precursors leading to chalcogen deposition can also serve as a useful approach to nanostructured chalcogen composites and IVA group (Si, Ge, Sn) element chalcogenides provided that it is carried out simultaneously with laser photolysis or thermolysis of polymer and IVA group element precursor.

  20. All-photonic drying and sintering process via flash white light combined with deep-UV and near-infrared irradiation for highly conductive copper nano-ink

    Science.gov (United States)

    Hwang, Hyun-Jun; Oh, Kyung-Hwan; Kim, Hak-Sung

    2016-01-01

    We developed an ultra-high speed photonic sintering method involving flash white light (FWL) combined with near infrared (NIR) and deep UV light irradiation to produce highly conductive copper nano-ink film. Flash white light irradiation energy and the power of NIR/deep UV were optimized to obtain high conductivity Cu films. Several microscopic and spectroscopic characterization techniques such as scanning electron microscopy (SEM), a x-ray diffraction (XRD), and Fourier-transform infrared (FT-IR) spectroscopy were employed to characterize the Cu nano-films. Optimally sintered Cu nano-ink films produced using a deep UV-assisted flash white light sintering technique had the lowest resistivity (7.62 μΩ·cm), which was only 4.5-fold higher than that of bulk Cu film (1.68 μΩ•cm).

  1. "Know What to Do If You Encounter a Flash Flood": Mental Models Analysis for Improving Flash Flood Risk Communication and Public Decision Making.

    Science.gov (United States)

    Lazrus, Heather; Morss, Rebecca E; Demuth, Julie L; Lazo, Jeffrey K; Bostrom, Ann

    2016-02-01

    Understanding how people view flash flood risks can help improve risk communication, ultimately improving outcomes. This article analyzes data from 26 mental models interviews about flash floods with members of the public in Boulder, Colorado, to understand their perspectives on flash flood risks and mitigation. The analysis includes a comparison between public and professional perspectives by referencing a companion mental models study of Boulder-area professionals. A mental models approach can help to diagnose what people already know about flash flood risks and responses, as well as any critical gaps in their knowledge that might be addressed through improved risk communication. A few public interviewees mentioned most of the key concepts discussed by professionals as important for flash flood warning decision making. However, most interviewees exhibited some incomplete understandings and misconceptions about aspects of flash flood development and exposure, effects, or mitigation that may lead to ineffective warning decisions when a flash flood threatens. These include important misunderstandings about the rapid evolution of flash floods, the speed of water in flash floods, the locations and times that pose the greatest flash flood risk in Boulder, the value of situational awareness and environmental cues, and the most appropriate responses when a flash flood threatens. The findings point to recommendations for ways to improve risk communication, over the long term and when an event threatens, to help people quickly recognize and understand threats, obtain needed information, and make informed decisions in complex, rapidly evolving extreme weather events such as flash floods.

  2. Asymmetric Programming: A Highly Reliable Metadata Allocation Strategy for MLC NAND Flash Memory-Based Sensor Systems

    Science.gov (United States)

    Huang, Min; Liu, Zhaoqing; Qiao, Liyan

    2014-01-01

    While the NAND flash memory is widely used as the storage medium in modern sensor systems, the aggressive shrinking of process geometry and an increase in the number of bits stored in each memory cell will inevitably degrade the reliability of NAND flash memory. In particular, it's critical to enhance metadata reliability, which occupies only a small portion of the storage space, but maintains the critical information of the file system and the address translations of the storage system. Metadata damage will cause the system to crash or a large amount of data to be lost. This paper presents Asymmetric Programming, a highly reliable metadata allocation strategy for MLC NAND flash memory storage systems. Our technique exploits for the first time the property of the multi-page architecture of MLC NAND flash memory to improve the reliability of metadata. The basic idea is to keep metadata in most significant bit (MSB) pages which are more reliable than least significant bit (LSB) pages. Thus, we can achieve relatively low bit error rates for metadata. Based on this idea, we propose two strategies to optimize address mapping and garbage collection. We have implemented Asymmetric Programming on a real hardware platform. The experimental results show that Asymmetric Programming can achieve a reduction in the number of page errors of up to 99.05% with the baseline error correction scheme. PMID:25310473

  3. STUDY ON THE PHOTOLYSIS MECHANISM OF POLYESTER FROM SUCCINIC ACID AND N-β-HYDROXYETHYL 2,2,6,6-TETRAMETHYL-4-HYDROXY PIPERIDINE (TINUVIN-622)

    Institute of Scientific and Technical Information of China (English)

    PAN Jiangqing; CUI Song

    1988-01-01

    The photolysis mechanism of polyester of succinic acid with N-β-hydroxyethyl 2,2,6,6-tetramethyl-4-hydroxy piperidine (Tinuvin-622) has been studied by instrumental analysis. The results show that Tinuvin-622 can be easily photolysed. Based on the results of IR, NMR, ESR, GPC, GC, MS, the photolysis mechanism of Tinuvin-622 has been proposed.

  4. Electro-optic sampling of THz pulses at the CTR source at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Wunderlich, Steffen

    2012-06-15

    Several applications in material science, non-linear optics and solid-state physics require short pulses with a high pulse energy of radiation in the far-infrared and in the terahertz (THz) regime in particular. As described in the following, coherent transition radiation generated by high-relativistic electron bunches at FLASH provides broadband single-cycle pulses of sub-picosecond length. The pulses are characterized using the quantitative and time-resolved technique of electro-optic sampling showing peak field strengths in the order of 1 MV/cm.

  5. Carbon nanotube-templated polyaniline nanofibers: synthesis, flash welding and ultrafiltration membranes

    Science.gov (United States)

    Liao, Yaozu; Yu, Deng-Guang; Wang, Xia; Chain, Wei; Li, Xin-Gui; Hoek, Eric M. V.; Kaner, Richard B.

    2013-04-01

    Electro-active switchable ultrafiltration membranes are of great interest due to the possibility of external control over permeability, selectivity, anti-fouling and cleaning. Here, we report on hybrid single-walled carbon nanotube (SWCNT)-polyaniline (PANi) nanofibers synthesized by in situ polymerization of aniline in the presence of oxidized SWCNTs. The composite nanofibers exhibit unique morphology of core-shell (SWCNT-PANi) structures with average total diameters of 60 nm with 10 to 30 nm thick PANi coatings. The composite nanofibers are easily dispersed in polar aprotic solvents and cast into asymmetric membranes via a nonsolvent induced phase separation. The hybrid SWCNT-PANi membranes are electrically conductive at neutral pH and exhibit ultrafiltration-like permeability and selectivity when filtering aqueous suspensions of 6 nm diameter bovine serum albumin and 48 nm diameter silica particles. A novel flash welding technique is utilized to tune the morphology, porosity, conductivity, permeability and nanoparticle rejection of the SWCNT-PANi composite ultrafiltration membranes. Upon flash welding, both conductivity and pure water permeability of the membranes improves by nearly a factor of 10, while maintaining silica nanoparticle rejection levels above 90%. Flash welding of SWCNT-PANi composite membranes holds promise for formation of electrochemically tunable membranes.Electro-active switchable ultrafiltration membranes are of great interest due to the possibility of external control over permeability, selectivity, anti-fouling and cleaning. Here, we report on hybrid single-walled carbon nanotube (SWCNT)-polyaniline (PANi) nanofibers synthesized by in situ polymerization of aniline in the presence of oxidized SWCNTs. The composite nanofibers exhibit unique morphology of core-shell (SWCNT-PANi) structures with average total diameters of 60 nm with 10 to 30 nm thick PANi coatings. The composite nanofibers are easily dispersed in polar aprotic solvents and

  6. Post-event analysis and flash flood hydrology in Slovakia

    Directory of Open Access Journals (Sweden)

    Hlavčová Kamila

    2016-12-01

    Full Text Available This work examines the main features of the flash flood regime in Central Europe as revealed by an analysis of flash floods that have occurred in Slovakia. The work is organized into the following two parts: The first part focuses on estimating the rainfall-runoff relationships for 3 major flash flood events, which were among the most severe events since 1998 and caused a loss of lives and a large amount of damage. The selected flash floods occurred on the 20th of July, 1998, in the Malá Svinka and Dubovický Creek basins; the 24th of July, 2001, at Štrbský Creek; and the 19th of June, 2004, at Turniansky Creek. The analysis aims to assess the flash flood peaks and rainfall-runoff properties by combining post-flood surveys and the application of hydrological and hydraulic post-event analyses. Next, a spatially-distributed hydrological model based on the availability of the raster information of the landscape’s topography, soil and vegetation properties, and rainfall data was used to simulate the runoff. The results from the application of the distributed hydrological model were used to analyse the consistency of the surveyed peak discharges with respect to the estimated rainfall properties and drainage basins. In the second part these data were combined with observations from flash flood events which were observed during the last 100 years and are focused on an analysis of the relationship between the flood peaks and the catchment area. The envelope curve was shown to exhibit a more pronounced decrease with the catchment size with respect to other flash flood relationships found in the Mediterranean region. The differences between the two relationships mainly reflect changes in the coverage of the storm sizes and hydrological characteristics between the two regions.

  7. Atmospheric Rivers, Floods, and Flash Floods in California

    Science.gov (United States)

    Skelly, Klint T.

    Atmospheric Rivers (ARs) are long (>2000 km), narrow (<1000 km) corridors of enhanced vertically integrated water vapor (IWV) and enhanced IWV transport (IVT). The landfall of ARs along the U.S. West Coast have been linked to extreme precipitation and flooding/flash flooding in regions of complex topography. The objective of this study is to investigate the relationship between a 10 water-year (2005-2014) climatology of floods, flash floods, and landfalling ARs. The ARs in this study are defined using IVT following the Rutz et al. (2013) methodology, whereas floods and flash floods are identified by the National Centers for Environmental Information (NCEI) Storm Events Database. The results of this study indicate that landfalling ARs are present on a majority of days that there are floods in northern California. Landfalling ARs are predominantly present on a majority of days that there are flash flood reports during the cold-season (November-March); however, the North American monsoon is present on days that there are flash flood reports during the warm-season (April-October). Two exemplary case studies are provided to illustrate the hydrologic impact of landfalling ARs. The first case study illustrated a flood event that occurred in associated with three landfalling ARs that produced 800 mm in regions over the Russian River watershed in northern California and the second case study illustrated a flash flood event that occurred in association with a landfalling AR that produced ˜225 mm of precipitation in regions over the Santa Ynez xii watershed in which produced a flash flood over the southern portions of Santa Barbara County in southern California.

  8. 适用于FlashMemory的快速响应的低压差稳压器%A Fast-Transient-Response LDO for Flash Memory

    Institute of Scientific and Technical Information of China (English)

    郭家荣; 冉峰

    2013-01-01

    A low-dropout regulator (LDO ) without off-chip capacitor for flash memory application is presented in this paper .Techniques of Miller compensation and adaptive biasing are employed to achieve high stability and enhanced loop bandwidth while maintaining low quiescent current and high current efficiency .Simultaneously ,inner small capacitor is used to enhance load regulation through its coupling effect to implement high-speed feedback loop . The proposed LDO is implemented in 90nm process ,and can regulates the output voltage at 1 .3 V from supply ranging from 1 .45~3 .8 V ,providing maximum output current of 10 mA .The settling time of the proposed LDO is only 20 ns when output current changes from low to high for flash memory .The active chip area is 40μm*280μm .%提出一种适用于flash memory的无片外电容的低压差稳压器设计.利用米勒补偿和自适应基准技术获取高稳定性和增强的瞬态.该低压差稳压器利用片内小电容作为频率补偿的同时还通过它的耦合效应形成高速反馈环路以获得快速的瞬态响应.该电路在低负载情况下具有很低的静态电流和在高负载情况下的高电流效率.提出的稳压器采用90nm工艺,在1.45V到3.8V操作电压范围内,输出1.3V的调制电压和10mA的最大输出电流.对于Flash Memory应用来说,当负载瞬态变化时,提出的低压差稳压器的建立时间仅仅为20 ns .芯片面积是40μm*280μm .

  9. Identification and ranging of lightning flashes using co-located antennas of different geometry

    Science.gov (United States)

    Bennett, A. J.

    2013-12-01

    A new technique for detecting and ranging lightning flashes up to approximately 100 km away is described. The technique uses a novel method of discriminating between lightning and non-lightning sources of quasi-electrostatic field change by comparison of the signal strength measured simultaneously on two co-located antennas, which is a function of their different geometry and exposure to the atmospheric electric field. In addition to detection of all types of lightning within range, the system also has the capability of detecting and classifying other sources of rapid electric field change associated with thunderstorm or shower cloud activity, such as from nearby corona brush discharge, strong space charge variability and charged precipitation. Real-time lightning flash detection and ranging combined with monitoring of initial storm electrification processes provides a comprehensive method of local severe weather warning. Since the operating frequency of 1-50 Hz lies below man-made sources of radio signals, the technique is considered especially useful for sites with strong radio interference.

  10. Photosensitivity to Triflusal: Formation of a Photoadduct with Ubiquitin Demonstrated by Photophysical and Proteomic Techniques

    Directory of Open Access Journals (Sweden)

    E Nuin

    2016-08-01

    Full Text Available Triflusal is a platelet aggregation inhibitor chemically related to acetylsalicylic acid, which is used for the prevention and/or treatment of vascular thromboembolisms, which acts as a prodrug. Actually, after oral administration it is absorbed primarily in the small intestine, binds to plasma proteins (99% and is rapidly biotransformed in the liver into its deacetylated active metabolite 2-hydroxy-4-trifluoromethylbenzoic acid (HTB. In healthy humans, the half-life of triflusal is ca. 0.5 h, whereas for HTB it is ca. 35 h. From a pharmacological point of view, it is interesting to note that HTB is itself highly active as a platelet anti-aggregant agent. Indeed, studies on the clinical profile of both drug and metabolite have shown no significant differences between them.It has been evidenced that HTB displays ability to induce photoallergy in humans. This phenomenon involves a cell-mediated immune response, which is initiated by covalent binding of a light-activated photosensitizer (or a species derived therefrom to a protein. In this context, small proteins like ubiquitin could be appropriate models for investigating covalent binding by means of MS/MS and peptide fingerprint analysis. In previous work, it was shown that HTB forms covalent photoadducts with isolated lysine. Interestingly, ubiquitin contains seven lysine residues that could be modified by a similar reaction. With this background, the aim of the present work is to explore adduct formation between the triflusal metabolite and ubiquitin as model protein upon sunlight irradiation, combining proteomic and photophysical (fluorescence and laser flash photolysis techniques.Photophysical and proteomic analysis demonstrate monoadduct formation as the major outcome of the reaction. Interestingly, addition can take place at any of the -amino groups of the lysine residues of the protein and involves replacement of the trifluoromethyl moiety with a new amide function. This process can in

  11. Direct UV photolysis of selected pharmaceuticals, personal care products and endocrine disruptors in aqueous solution.

    Science.gov (United States)

    Carlson, Jules C; Stefan, Mihaela I; Parnis, J Mark; Metcalfe, Chris D

    2015-11-01

    Pharmaceuticals and personal care products (PPCPs), and endocrine disrupting compounds (EDCs) are micropollutants of emerging concern that have been detected in the aquatic environment and in some cases, in drinking water at nanogram per liter levels. The goal of this study was to evaluate the removal of 15 model PPCPs and EDCs from water by direct UV photolysis, using either low (LP)-or medium (MP) -pressure mercury vapor arc lamps. Some of the model compounds are either weak bases or weak acids, and therefore, the pKa values were determined or confirmed for those compounds using spectrophotometric titrations. The molar absorption coefficients of ionized and non-ionized forms were also determined. The quantum yields at 253.7 nm in phosphate buffer solutions of pH 7.2 were determined to be 0.033 ± 0.004 for sulfamethoxazole, 0.0035 ± 0.0008 for sulfachloropyridazine, 0.006 ± 0.002 for acetaminophen, 0.34 ± 0.07 for triclosan, 0.35 ± 0.14 for estrone, 0.08 ± 0.05 for 17α-ethinylestradiol, 0.086 ± 0.012 for ibuprofen. The quantum yield for 4-n-nonylphenol photolysis at 253.7 nm varied with the initial concentration from 0.32 ± 0.08 at 23 μg/L to 0.092 ± 0.006 at 230 μg/L. The pseudo-first order rate constants determined for direct photolysis at 253.7 nm of the studied micropollutants followed the order: triclosan ≈ sulfamethoxazole > 4-n-nonylphenol ≈ sulfachloropyridazine ≈ estrone > acetaminophen ≈ 17α-ethinylestradiol ≈ ibuprofen. In contrast to the results observed for the monochromatic radiation (LP lamp), all 15 model compounds photolyzed under exposure to the broadband radiation emitted by the MP lamp. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Nitrate ion photolysis in thin water films in the presence of bromide ions.

    Science.gov (United States)

    Richards, Nicole K; Wingen, Lisa M; Callahan, Karen M; Nishino, Noriko; Kleinman, Michael T; Tobias, Douglas J; Finlayson-Pitts, Barbara J

    2011-06-16

    Nitrate ions commonly coexist with halide ions in aged sea salt particles, as well as in the Arctic snowpack, where NO(3)(-) photochemistry is believed to be an important source of NO(y) (NO + NO(2) + HONO + ...). The effects of bromide ions on nitrate ion photochemistry were investigated at 298 ± 2 K in air using 311 nm photolysis lamps. Reactions were carried out using NaBr/NaNO(3) and KBr/KNO(3) deposited on the walls of a Teflon chamber. Gas phase halogen products and NO(2) were measured as a function of photolysis time using long path FTIR, NO(y) chemiluminescence and atmospheric pressure ionization mass spectrometry (API-MS). Irradiated NaBr/NaNO(3) mixtures show an enhancement in the rates of production of NO(2) and Br(2) as the bromide mole fraction (χ(NaBr)) increased. However, this was not the case for KBr/KNO(3) mixtures where the rates of production of NO(2) and Br(2) remained constant over all values of χ(KBr). Molecular dynamics (MD) simulations show that the presence of bromide in the NaBr solutions pulls sodium toward the solution surface, which in turn attracts nitrate to the interfacial region, allowing for more efficient escape of NO(2) than in the absence of halides. However, in the case of KBr/KNO(3), bromide ions do not appreciably affect the distribution of nitrate ions at the interface. Clustering of Br(-) with NO(3)(-) and H(2)O predicted by MD simulations for sodium salts may facilitate a direct intermolecular reaction, which could also contribute to higher rates of NO(2) production. Enhanced photochemistry in the presence of halide ions may be important for oxides of nitrogen production in field studies such as in polar snowpacks where the use of quantum yields from laboratory studies in the absence of halide ions would lead to a significant underestimate of the photolysis rates of nitrate ions.

  13. A radar-based flash flood forecasting for the Llobregat river basin in the Catalonia region (Spain)

    OpenAIRE

    Quintero Duque, Felipe; Versini, Pierre Antonie; Baltas, Evangelos; Berenguer Ferrer, Marc; Sempere Torres, Daniel

    2011-01-01

    In this research paper, a flash flood modeling system implemented in a Mediterranean river basin is presented. Radar precipitation estimation along with hydrological modeling techniques are implemented within the system for simulating the runoff generation and routing processes occurring in the catchment. However, there exists an uncertainty related with the estimation of radar precipitation (Zawadzki, 1984) and from model calibration (Beven, 2006). Such uncertainty is propagated to the...

  14. Central Flash Analysis of the 29 June 2015 Occultation

    Science.gov (United States)

    Person, Michael J.; Bosh, A. S.; Sickafoose, A. A.; Zuluaga, C. A.; Levine, S. E.; Pasachoff, J. M.; Babcock, B. A.; Dunham, E. W.; McLean, I.; Wolf, J.; Abe, F.; Becklin, E.; Bida, T. A.; Bright, L. P.; Brothers, T. C.; Christie, G.; Collins, P. L.; Durst, R. F.; Gilmore, A. C.; Hamilton, R.; Harris, H. C.; Johnson, C.; Kilmartin, P. M.; Kosiarek, M. R.; Leppik, K.; Logsdon, S. E.; Lucas, R.; Mathers, S.; Morley, C. J. K.; Natusch, T.; Nelson, P.; Ngan, H.; Pfueller, E.; Roeser, H.-P.; Sallum, S.; Savage, M.; Seeger, C. H.; Siu, H.; Stockdale, C.; Suzuki, D.; Thanathibodee, T.; Tilleman, T.; Tristram, P. J.; Van Cleeve, J.; Varughese, C.; Weisenbach, L. W.; Widen, E.; Wiedemann, M.

    2015-11-01

    After an extensive prediction effort, the 29 June 2015 occultation by Pluto was observed from both airborne (Stratospheric Observatory for Infrared Astronomy - SOFIA) and numerous ground-based telescopes (Bosh et al. - this meeting). Real-time prediction updates allowed placement of the SOFIA telescope with its four detectors deep within the central-flash region of the atmospheric occultation. Fortuitously, the Mount John University Observatory (Lake Tekapo, New Zealand) was also within the central-flash region (Pasachoff et al. - this meeting). This happenstance resulted in multiple central-flash detections in several colors from each facility allowing direct comparison of different areas of the central-flash evolute.Here we examine and discuss the central-flash signatures from the highest signal-to-noise light curves from each facility. The relative orientations and asymmetries in the central flashes allow us to use them to tightly constrain the lower atmospheric ellipticity and orientation of likely winds with respect to Pluto’s figure. The ratio of the two separate central flashes is also a strong constraint on the geometric solution for the full occultation data set, and the absolute height of the central flashes with respect to those expected for a clear isothermal atmosphere places constraints on haze densities and thermal gradients in Pluto’s lower atmosphere. We can also compare the central-flash signatures in several colors (similar to Sickafoose et. al - this meeting) to establish bounds on haze-particle sizes in the lower atmosphere.SOFIA is jointly operated by the Universities Space Research Association, Inc. (USRA), under NASA contract NAS2-97001, and the Deutsches SOFIA Institut (DSI) under DLR contract 50 OK 0901 to the University of Stuttgart. Support for this work was provided, in part, by NASA grants SSO NNX15AJ82G (Lowell Observatory), PA NNX10AB27G (MIT), and PA NNX12AJ29G (Williams College), as well as the National Research Foundation of

  15. Multi-Level Bitmap Indexes for Flash Memory Storage

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Kesheng; Madduri, Kamesh; Canon, Shane

    2010-07-23

    Due to their low access latency, high read speed, and power-efficient operation, flash memory storage devices are rapidly emerging as an attractive alternative to traditional magnetic storage devices. However, tests show that the most efficient indexing methods are not able to take advantage of the flash memory storage devices. In this paper, we present a set of multi-level bitmap indexes that can effectively take advantage of flash storage devices. These indexing methods use coarsely binned indexes to answer queries approximately, and then use finely binned indexes to refine the answers. Our new methods read significantly lower volumes of data at the expense of an increased disk access count, thus taking full advantage of the improved read speed and low access latency of flash devices. To demonstrate the advantage of these new indexes, we measure their performance on a number of storage systems using a standard data warehousing benchmark called the Set Query Benchmark. We observe that multi-level strategies on flash drives are up to 3 times faster than traditional indexing strategies on magnetic disk drives.

  16. An Evaluation of Flash Cells Used in Critical Applications

    Science.gov (United States)

    Katz, Richard B.; Flowers, David; Bergevin, Keith

    2016-01-01

    Due to the common use of Flash technology in many commercial and industrial Programmable Logic Devices (PLDs) such as FPGAs and mixed-signal microcontrollers, flash technology is being utilized in fuzed munition applications. This presents a long-term reliability issue for both DoD and NASA safety- and mission-critical applications. A thorough understanding of the data retention failure modes and statistics associated with Flash data retention is of vital concern to the fuze safety community. A key retention parameter for a flash cell is the threshold voltage (VTH), which is an indirect indicator of the amount of charge stored on the cells floating gate. Initial test results based on a study of charge loss in flash cells in an FPGA device is presented. Statistical data taken from a small sample set indicates quantifiable charge loss for devices stored at both room temperature and 150 C. Initial evaluation of the distribution of threshold voltage in a large sample set (800 devices) is presented. The magnitude of charge loss from exposure to electrostatic discharge and electromagnetic fields is measured and presented. Simulated data (and measured data as available) resultant from harsh-environment testing (neutron, heavy ion, EMP) is presented.

  17. Venlafaxine and desvenlafaxine in the management of menopausal hot flashes

    Directory of Open Access Journals (Sweden)

    Johnson ED

    2011-09-01

    Full Text Available Vasomotor flushes are common complaints of women during and after menopause, affecting about 75 percent of this population. Estrogen therapy is the most effective treatment for hot flashes. However, there are a significant number of women who have contraindications or choose not to use estrogen due to potential risks such as breast cancer and thromboembolic disorders. These women need alternative options. The selective norepinephrine reuptake inhibitors, venlafaxine and desvenlafaxine, have shown efficacy in alleviating hot flashes.Objective: The purpose of this review is to assess the efficacy and tolerability of these two agents for treatment of hot flashes in healthy postmenopausal women.Methods: A literature search of the MEDLINE and Ovid databases from inception to June 2011 was conducted. Randomized controlled trials, published in English, with human participants were included. Studies included postmenopausal women, and trials with breast cancer only populations were excluded.Results: Venlafaxine reduced hot flashes by 37 to 61 percent and desvenlafaxine by 55 to 69 percent. Both agents were well tolerated. The most common adverse effects were headache, dry mouth, nausea, insomnia, somnolence, and dizziness.Conclusion: Based on the evidence, venlafaxine and desvenlafaxine are both viable options for reducing the frequency and severity of hot flashes.

  18. Multi-Level Bitmap Indexes for Flash Memory Storage

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Kesheng; Madduri, Kamesh; Canon, Shane

    2010-07-23

    Due to their low access latency, high read speed, and power-efficient operation, flash memory storage devices are rapidly emerging as an attractive alternative to traditional magnetic storage devices. However, tests show that the most efficient indexing methods are not able to take advantage of the flash memory storage devices. In this paper, we present a set of multi-level bitmap indexes that can effectively take advantage of flash storage devices. These indexing methods use coarsely binned indexes to answer queries approximately, and then use finely binned indexes to refine the answers. Our new methods read significantly lower volumes of data at the expense of an increased disk access count, thus taking full advantage of the improved read speed and low access latency of flash devices. To demonstrate the advantage of these new indexes, we measure their performance on a number of storage systems using a standard data warehousing benchmark called the Set Query Benchmark. We observe that multi-level strategies on flash drives are up to 3 times faster than traditional indexing strategies on magnetic disk drives.

  19. X-ray flashes in ROSAT PSPC data

    Energy Technology Data Exchange (ETDEWEB)

    Sun, X.; Li, H.; Fenimore, E.E. [Los Alamos National Lab., NM (United States); Wang, Q.D. [Northwestern Univ., Evanston, IL (United States)

    1998-12-01

    The authors find 24 short (200--2,500s) X-ray flashes from all the ROSAT Position Sensitive Proportional Counter (PSPC) observations above galactic latitude 30 degrees ({approximately} 9.6 Msec) and some observations toward low latitudes ({approximately} 2.4 Msec). The brightest flash is quite extraordinary. Its flux rises from nondetection by a factor of > 200 in less than 100 sec. Its spectrum can be fitted either by a thermal plasma model with kT {ge} 2.4 keV, or by a single power-law with the photon number index of {approx} {minus}1.7. Photon statistics are not sufficient to obtain spectra for other flashes. The flash event fields can vary from optically crowded regions to blank fields. Although eight flashes are found from observations from nearby galaxies, and three of them are within the optical extent of their corresponding galaxies, they could not statistically establish that there are two different populations between nearby galaxies and control fields.

  20. Environmental Effects on Data Retention in Flash Cells

    Science.gov (United States)

    Katz, Rich; Flowers, David; Bergevin, Keith

    2017-01-01

    Flash technology is being utilized in fuzed munition applications and, based on the development of digital logic devices in the commercial world, usage of flash technology will increase. Antifuse technology, prevalent in non-volatile field programmable gate arrays (FPGAs), will eventually be phased out as new devices have not been developed for approximately a decade. The reliance on flash technology presents a long-term reliability issue for both DoD and NASA safety- and mission-critical applications. A thorough understanding of the data retention failure modes and statistics associated with Flash data retention is of vital concern to the fuze safety community. A key retention parameter for a flash cell is the threshold voltage (VTH), which is an indirect indicator of the amount of charge stored on the cells floating gate. This paper will present the results of our on-going tests: long-term storage at 150 C for a small population of devices, neutron radiation exposure, electrostatic discharge (ESD) testing, and the trends of large populations (over 300 devices for each condition) exposed to three difference temperatures: 25 C, 125 C, and 150 C.