Primary photochemical processes for Pt(iv) diazido complexes prospective in photodynamic therapy of tumors.

Science.gov (United States)

Shushakov, Anton A; Pozdnyakov, Ivan P; Grivin, Vjacheslav P; Plyusnin, Victor F; Vasilchenko, Danila B; Zadesenets, Andrei V; Melnikov, Alexei A; Chekalin, Sergey V; Glebov, Evgeni M

2017-07-25

Diazide diamino complexes of Pt(iv) are considered as prospective prodrugs in oxygen-free photodynamic therapy (PDT). Primary photophysical and photochemical processes for cis,trans,cis-[Pt(N 3 ) 2 (OH) 2 (NH 3 ) 2 ] and trans,trans,trans-[Pt(N 3 ) 2 (OH) 2 (NH 3 ) 2 ] complexes were studied by means of stationary photolysis, nanosecond laser flash photolysis and ultrafast kinetic spectroscopy. The process of photolysis is multistage. The first stage is the photosubstitution of an azide ligand to a water molecule. This process was shown to be a chain reaction involving redox stages. Pt(iv) and Pt(iii) intermediates responsible for the chain propagation were recorded using ultrafast kinetic spectroscopy and nanosecond laser flash photolysis. The mechanism of photosubstitution is proposed.

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

International Nuclear Information System (INIS)

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 2 - and (CNS) 2 - with tryptophan generate the same initial radical as uv-excited photoionization

Unit for the nanosecond, laser, pulse photolysis in the ultraviolet region for a combination of photochemical studies

Energy Technology Data Exchange (ETDEWEB)

Pikel' ni, V F; Kolosov, V A; Kiryukhin, Yu I; Kondrat' ev, V A; Borovkova, V A; Tarasov, E N

1976-06-01

A description is given of a nanosecond laser unit for pulse photolysis in the ultraviolet region, by means of which it is possible to investigate the kinetics of the death of interstitial particles, their optical absorption and luminescence spectra, and also the photoconductivity induced by the laser radiation, at a time resolution of about 15 ns. As a source of powerful, stable uv-radiation, use is made of the fourth harmonic (266 nm) of radiation from an aluminum-yttrium garnet containing neodymium. The radiation power of the fourth harmonic attained 2 MW. The time of bringing the unit into the operating mode is considerably shortened because of the possibility of operating in a frequency mode. Absorption spectra of carbazole in hexane were obtained at 20/sup 0/C. (SJR)

Magnetic Field Effect: An Efficient Tool To Investigate The Mechanism Of Reactions Using Laser Flash Photolysis Technique

International Nuclear Information System (INIS)

Basu, Samita; Bose, Adity; Dey, Debarati

2008-01-01

Magnetic field effect combined with laser flash photolysis technique have been used to study the mechanism of interactions between two drug-like quinone molecules, Menadione (1,4-naphthoquinone, MQ) and 9, 10 Anthraquinone (AQ) with one of the DNA bases, Adenine in homogeneous acetonitrile/water and heterogeneous micellar media. A switchover in reaction mode from electron transfer to hydrogen abstraction is observed with MQ on changing the solvent from acetonitrile/water to micelle; whereas, AQ retains its mode of interaction towards Adenine as electron transfer in both the media due to its bulky structure compared to MQ

Assignment and analysis of the A3Πi-X3Σ- transition of the CCO molecule. Formation and disappearance of the CCO's X3Σ- state during flash photolysis of the carbon suboxide

International Nuclear Information System (INIS)

Devillers, Claude

1971-01-01

As the C 2 O radical appeared to be the necessary intermediate compound which could lead from atomic carbon to carbon suboxide by a chain of elementary reactions for the study of the effect of radiations on CO, this research thesis, after a recall on the nature of primary compounds of carbon suboxide photolysis, presents experimental techniques aimed at the investigation of C 2 O: flash photolysis to observe it with low resolution, experimental set-up to record its spectrum with a high resolution, experimental set-up to observe it by pulse radiolysis of carbon oxide. The author reports the identification and analysis of the C 2 O spectrum, and discusses the formation and disappearance of the CCO's X 3 Σ - state with or without the presence of sensors during flash photolysis of the carbon suboxide [fr

Flash photolysis and pulse radiolysis of the Co(sep)3+-X- (sep = sepulchrate; X = I, Br) systems in aqueous solution

International Nuclear Information System (INIS)

Pina, F.; Maestri, M.; Ballardini, R.; Mulazzani, Q.G.; D'Angelantonio, M.; Balzani, V.

1986-01-01

The Co(sep) 3+ complex (sep = sepulchrate = 1,3,6,8,10,13,16,19-octaazabicyclo[6.6.6]eicosane) in aqueous solution forms ion pairs with the I - and Br - anions, which exhibit a relatively intense charge-transfer absorption. In deoxygenated aqueous solution no net reaction is obtained upon continuous light excitation in the ion-pair charge-transfer bands, but formation of transient species is observed in flash photolysis experiments. For the Co(sep) 3+ -I - system, I 2 - ions are formed that decay in the 50-μs time scale to give I 3 - . The latter species disappears in a time scale of seconds, leading the system back to the preexcitation conditions. For the Co(sep) 3+ -Br - system, only formation of the Br 2 - transient is observed, followed by regeneration of the preexcitation conditions in the 20-μs time scale. In order to elucidate the kinetic aspects of the transient formation and disappearance, pulse radiolysis experiments on the Co(sep) 3+ -I - and Co(sep) 3+ -Br - systems have been carried out. The rate constants of the reactions of Co(sep) 2+ with I 2 - , I 3 - , and Br 2 - have been measured, and a complete picture of the redox processes that follow flash photolysis and pulse radiolysis excitations has been obtained. 5 figures

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...... dependent quantum yields of 0.3-1.0 mol/Einstein. Mass spectroscopic studies of the product solutions demonstrate formation of S8, presumably from the decomposition of NS. The quantitative photochemical behaviors of 1 and the nitrosyl analog 2 are compared. Udgivelsesdato: Jan....

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 solution O3 P is formed in a small...

Construction of a flash-photolysis apparatus having a short discharge time; Realisation d'un appareil de photolyse-eclair a faible duree de decharge

Energy Technology Data Exchange (ETDEWEB)

Devillers, C. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

Flash photolysis aims at reaching directly the primary mechanisms resulting from the action of light on an absorbent matter. This makes it necessary to produce a flash as short and as bright as possible. Our main effort was directed towards reducing the duration of the flash by decreasing the self-inductance of the discharge circuit. A description of this circuit and study of the characteristics of the apparatus are followed by a short description of the two analytical methods: flash spectrography and absorption spectrophotometry at a given wave-length. (author) [French] La photolyse-eclair cherche a atteindre directement les mecanismes primaires resultant de l'action de la lumiere sur une matiere absorbante. Ceci amene a produire un eclair aussi bref et intense que possible. Notre effort s'est porte sur la reduction de duree de l'eclair par diminution de la self-induction du circuit de decharge. Une description de ce circuit et une etude des caracteristiques de l'appareil precedent une breve description des deux methodes d'analyse; spectrographie eclair et spectrophotometrie d'absorption a longueur d'onde choisie. (auteur)

Flash photolysis of carbon dioxide in the far ultra-violet; Photolyse-eclair de l'anhydride carbonique dans l'ultra-violet lointain

Energy Technology Data Exchange (ETDEWEB)

Barat, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1970-07-01

The flash photolysis of CO{sub 2} (3 torr) in the far ultra-violet, down to the transparency limit of lithium fluoride, produces vibrationally excited CO in its {chi}{sup 1}{sigma} electronic ground state and an electronically excited oxygen atom O({sup 1}D). After photolysis, the changes in the concentration of vibrationally de-excited CO in the 0 to 200 {mu}sec, time range are followed using absorption spectroscopy. These changes can be explained on the basis of three main competing reactions: CO({chi}{sup 1}{sigma}, {nu}'' = 0) + O({sup 1}D) {yields} CO{sub 2}({sup 1}{sigma}{sub g}{sup +}), O({sup 1}D) + CO{sub 2} {yields} O({sup 3}P) + CO{sub 2} and CO{sub 3}, CO(X{sup 1}{sigma}, {nu}'' = 1,2) + CO{sub 2} {yields} CO({chi}{sup 1}{sigma}, {nu}'' = 0) + CO{sub 2}. The values of the rate constants for these three reactions are determined by analog calculations. The effect of O({sup 1}D) scavenging or quenching gases on the oxidation reaction of CO by O({sup 1}D) is examined. A study of the flash photolysis of O{sub 2} in the presence of CO in the far ultra-violet makes it possible to eliminate the hypothesis that CO{sub 3} is involved in the reaction leading to the disappearance of CO after photolysis. (author) [French] La photolyse eclair de CO{sub 2} (3 torrs) dans l'ultraviolet lointain, jusqu'a la limite de transparence du fluorure de lithium, produit CO vibrationnellement excite dans son etat electronique fondamental X et un atome d'oxygene electroniquement excite O({sup 1}D). Apres photolyse, on suit par spectroscopie d'absorption l'evolution de la concentration de CO vibrationnellement desexcite dans la gamme de temps s'etendant de 0 a 200 {mu}s. Cette evolution s'explique en admettant trois reactions concurrentes principales: CO({chi}{sup 1}{sigma}, {nu}'' = 0) + O({sup 1}D) {yields} CO{sub 2}({sup 1}{sigma}{sub g}{sup +}), O({sup 1}D) + CO{sub 2} {yields} O({sup 3}P) + CO{sub 2} et CO{sub 3}, CO(X{sup 1}{sigma}, {nu}'' = 1,2) + CO{sub 2} {yields} CO

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 99mTc-complex with human serum albumin

International Nuclear Information System (INIS)

Pandurangi, R.S.; Lusiak, P.; Kuntz, R.R.; Volkert, W.A.; Rogowski, J.; Platz, M.S.

1998-01-01

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 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

265 nm laser flash photolysis of some ortho-substituted anilides and related N-formylkynurenine derivatives

Energy Technology Data Exchange (ETDEWEB)

Pileni, M P; Santus, R [Museum National d' Histoire Naturelle, 75 - Paris (France); Land, E J

1978-06-01

The physical and chemical properties of the triplet state of eight ortho-substituted anilides including N-formylkynurenine(FK), the major trp UV-photooxidation product and a remarkable photodynamic agent, have been investigated using both pulse radiolysis and 265 nm laser flash photolysis techniques. The molar extinction coefficient, the inter-system-crossing quantum yield and the oscillator strength of the T/sub 1/..-->..Tsub(n) absorption band (lambdasub(max)approximately equal 450nm) have been determined. It is shown that anilides having n..pi..* triplets readily react with most solvents whereas those having ..pi..,..pi..* triplets slowly react with alcohols. In both cases, the semi-reduced species are formed. In water, the formation of the semi-reduced species most probably involves the first excited singlet state. The triplet state properties of the FK derivatives (i.e. ortho-substituted anilides having a side chain bearing charged groups such as carboxylic or amino groups) are strongly modified by the ionization state of the charged side chain. In the case of the FK derivatives possessing an uncharged amino group, quenching of the triplet state occurs via a fast reversible electron transfer reaction from the NH/sub 2/ to the triplet anilide.

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

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. Copyright © 2015 Elsevier B.V. All rights reserved.

Photoionization of oxidized coenzyme Q in microemulsion: laser flash photolysis study in biomembrane-like system.

Science.gov (United States)

Li, Kun; Wang, Mei; Wang, Jin; Zhu, Rongrong; Sun, Dongmei; Sun, Xiaoyu; Wang, Shi-Long

2013-01-01

Photoexcitation to generate triplet state has been proved to be the main photoreaction in homogeneous system for many benzoquinone derivatives, including oxidized coenzyme Q (CoQ) and its analogs. In the present study, microemulsion of CoQ, a heterogeneous system, is employed to mimic the distribution of CoQ in biomembrane. The photochemistry of CoQ(10) in microemulsion and cyclohexane is investigated and compared using laser flash photolysis and results show that CoQ(10) undergoes photoionization via a monophotonic process to generate radical cation of CoQ(10) in microemulsion and photoexcitation to generate excited triplet state in cyclohexane. Meanwhile, photoreactions of duroquinone (DQ) and CoQ(0) in microemulsion are also investigated to analyze the influence of molecular structure on the photochemistry of benzoquinone derivatives in microemulsion. Results suggest that photoexcitation, which is followed by excited state-involved hydrogen-abstraction reaction, is the main photoreaction for DQ and CoQ(0) in microemulsion. However, photoexcited CoQ(0) also leads to the formation of hydrated electrons. The isoprenoid side chain-involved high resonance stabilization is proposed to explain the difference in photoreactions of CoQ(0) and CoQ(10) in microemulsion. Considering that microemulsion is close to biomembrane system, its photoionization in microemulsion may be helpful to understand the real photochemistry of biological quinones in biomembrane system. © 2012 Tongji University. Photochemistry and Photobiology © 2012 The American Society of Photobiology.

Early photolysis intermediates of gecko and bovine artificial visual pigments.

Science.gov (United States)

Lewis, J W; Liang, J; Ebrey, T G; Sheves, M; Livnah, N; Kuwata, O; Jäger, S; Kliger, D S

1997-11-25

Nanosecond laser photolysis measurements were conducted on digitonin extracts of artificial pigments prepared from the cone-type visual pigment, P521, of the Tokay gecko (Gekko gekko) retina. Artificial pigments were prepared by regeneration of bleached gecko photoreceptor membranes with 9-cis-retinal, 9-cis-14-methylretinal, or 9-cis-alpha-retinal. Absorbance difference spectra were recorded at a sequence of time delays from 30 ns to 60 microseconds following excitation with a pulse of 477-nm actinic light. Global analysis showed the kinetic data for all three artificial gecko pigments to be best fit by two-exponential processes. These two-exponential decays correspond to similar decays observed after photolysis of P521 itself, with the first process being the decay of the equilibrated P521 BathoP521 BSI mixture to P521 Lumi and the second process being the decay of P521 Lumi to P521 Meta I. In spite of its large blue shift relative to P521, iso-P521 displays a normal chloride depletion induced blue shift. Iso-P521's early intermediates up to Lumi were also blue-shifted, with the P521 BathoP521 BSI equilibrated mixture being 15 nm blue-shifted and P521 Lumi being 8 nm blue-shifted relative to the intermediates formed after P521 photolysis. The blue shift associated with the iso-pigment is reduced or disappears entirely by P521 Meta I. Similar blue shifts were observed for the early intermediates observed after photolysis of bovine isorhodopsin, with the Lumi intermediate blue-shifted 5 nm compared to the Lumi intermediate formed after photolysis of bovine rhodopsin. These shifts indicate that a difference exists between the binding sites of 9- and 11-cis pigments which persists for microseconds at 20 degrees C.

Investigation of N2O Production from 266 and 532 nm Laser Flash Photolysis of O3/N2/O2 Mixtures

Science.gov (United States)

Estupinan, E. G.; Nicovich, J. M.; Li, J.; Cunnold, D. M.; Wine, P. H.

2002-01-01

Tunable diode laser absorption spectroscopy has been employed to measure the amount of N2O produced from laser flash photolysis of O3/N2/O2 mixtures at 266 and 532 nm. In the 532 nm photolysis experiments very little N2O is observed, thus allowing an upper limit yield of 7 x 10(exp -8) to be established for the process O3 + N2 yield N2O + O2, where O3 is nascent O3 that is newly formed via O(3P(sub J)) + O2 recombination (with vibrational excitation near the dissociation energy of O3). The measured upper limit yield is a factor of approx. 600 smaller than a previous literature value and is approximately a factor of 10 below the threshold for atmospheric importance. In the 266 nm photolysis experiments, significant N2O production is observed and the N2O quantum yield is found to increase linearly with pressure over the range 100 - 900 Torr in air bath gas. The source of N2O in the 266 nm photolysis experiments is believed to be the addition reaction O(1D(sub 2)) + N2 + M yields (k(sub sigma)) N2O + M, although reaction of (very short-lived) electronically excited O3 with N2 cannot be ruled out by the available data. Assuming that all observed N2O comes from the O(1D(sub 2)) + N2 + M reaction, the following expression describes the temperature dependence of k(sub sigma) (in its third-order low-pressure limit) that is consistent with the N2O yield data: k(sub sigma) = (2.8 +/- 0.1) x 10(exp -36)(T/300)(sup -(0-88+0.36)) cm(sup 6) molecule(sup -2)/s, where the uncertainties are 2(sigma) and represent precision only. The accuracy of the reported rate coefficients at the 95% confidence level is estimated to be 30 - 40% depending on the temperature. Model calculations suggest that gas phase processes initiated by ozone absorption of a UV photon represent about 1.4% of the currently estimated global source strength of atmospheric N2O. However, these processes could account for a significant fraction of the oxygen mass-independent enrichment observed in atmospheric N2O, and

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.

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

Science.gov (United States)

Bose, Adity; Dey, Debarati; Basu, Samita

2008-04-01

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.

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

International Nuclear Information System (INIS)

Bose, Adity; Dey, Debarati; Basu, Samita

2008-01-01

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

Photobinding of tiaprofenic acid and suprofen to proteins and cells: a combined study using radiolabeling, antibodies and laser flash photolysis of model bichromophores.

Science.gov (United States)

Castell, J V; Hernández, D; Gómez-Lechón, M J; Lahoz, A; Miranda, M A; Morera, I M; Pérez-Prieto, J; Sarabia, Z

1998-11-01

Drug photoallergy is a matter of current concern. It involves the formation of drug-protein photoadducts (photoantigens) that may ultimately trigger an immunological response. Tyrosine residues appear to be key binding sites in proteins. The present work has investigated the photobinding of tiaprofenic and (TPA) and the closely related isomer suprofen (SUP) to proteins and cells by means of radioactive labelling and drug-directed antibodies. To ascertain whether preassociation with the protein may play a role in photoreactivity, two model bichromophoric compounds (TPA-Tyr and SUP-Tyr) have been prepared and studied by laser flash photolysis. The results of this work show that (a) TPA and SUP photobind to proteins with similar efficiencies, (b) both drugs form photoadducts that share a basic common structure, as they are recognized by the same antibody and (c) drug-protein preassociation must play a key role in photoreactivity, as indicated by the dramatic decrease in the triplet state lifetimes of the model bichromophores compared to the parent drugs.

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

Energy Technology Data Exchange (ETDEWEB)

Bose, Adity; Dey, Debarati; Basu, Samita [Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata-700 064 (India)], E-mail: samita.basu@saha.ac.in

2008-04-01

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.

Measured pulse width of sonoluminescence flashes in the form of resonance radiation

Science.gov (United States)

Giri, Asis; Arakeri, Vijay H.

1998-09-01

Recent studies have shown that the measured flash widths from single and multibubble sonoluminescence are in subnanosecond or even picosecond regime. Here, we provide conclusive evidence for the existence of nanosecond multibubble sonoluminescence. This has become possible by our ability to find a medium from which exclusive sodium D line resonance radiation as a form of sonoluminescence is possible. The measured flash width of this emission is found to be in the range of tens of nanoseconds and is sensitively dependent on experimental parameters. Our finding is important since all the earlier pulse width measurements have been limited to emission with the physical source or species responsible for observed optical radiation not being clearly identified. We propose that the presently observed resonance radiation is from ``soft'' bubble collapse as analyzed by V. Kamath et al. [J. Acoust. Soc. Am. 94, 248 (1993)].

Sphinx, the high speed flash radiography

International Nuclear Information System (INIS)

Anon.

1997-01-01

Sphinx (Nanosecond Pulse X-Photon Source) is the most compact (0.1 m 3 ) existing system which can generates short pulses (10 to 30 nanoseconds) of 5 to 180 keV X-photon radiation with a repeating cadence of 100 pulses per second and doses which can reach 2 mR at 1 m. This system was developed by the Research Group on Energetics of Ionized Media (GREMI) from the CNRS (French National Center for Scientific Research) and the University of Orleans (France). Sphinx is the smallest device from a series of compact X-ray sources ranging from 5 to 400 keV. These devices can have several possible applications such as the study of ultra-fast phenomena, the high cadence flash radiography in medicine, biology, materials studies, pre-ionizing of gas lasers, self-excitation and photo-ionization of atoms, molecules or aggregates. (J.S.)

Photophysics and Photochemistry of 2-Aminobenzoic Acid Anion in Aqueous Solution

Science.gov (United States)

Pozdnyakov, Ivan P.; Plyusnin, Victor F.; Grivin, Vjacheslav P.

2009-11-01

Nanosecond laser flash photolysis and absorption and fluorescence spectroscopy were used to study photochemical processes of 2-aminobenzoic acid anion (ABA-) in aqueous solutions. Excitation of this species gives rise to the ABA- triplet state to the ABA• radical and to the hydrated electron (eaq-). The last two species result from two-photon processes. In a neutral medium, the main decay channels of ABA- triplet state, the ABA• radical, and eaq- are T-T annihilation, recombination, and capture by the ABA- anion, respectively.

A laser flash photolysis and quantum chemical study of the fluorinated derivatives of singlet phenylnitrene.

Science.gov (United States)

Gritsan, N P; Gudmundsdóttir, A D; Tigelaar, D; Zhu, Z; Karney, W L; Hadad, C M; Platz, M S

2001-03-07

Laser flash photolysis (LFP, Nd:YAG laser, 35 ps, 266 nm, 10 mJ or KrF excimer laser, 10 ns, 249 nm, 50 mJ) of 2-fluoro, 4-fluoro, 3,5-difluoro, 2,6-difluoro, and 2,3,4,5,6-pentafluorophenyl azides produces the corresponding singlet nitrenes. The singlet nitrenes were detected by transient absorption spectroscopy, and their spectra are characterized by sharp absorption bands with maxima in the range of 300-365 nm. The kinetics of their decay were analyzed as a function of temperature to yield observed decay rate constants, k(OBS). The observed rate constant in inert solvents is the sum of k(R) + k(ISC) where k(R) is the absolute rate constant of rearrangement of singlet nitrene to an azirine and k(ISC) is the absolute rate constant of nitrene intersystem crossing (ISC). Values of k(R) and k(ISC) were deduced after assuming that k(ISC) is independent of temperature. Barriers to cyclization of 4-fluoro-, 3,5-difluoro-, 2-fluoro-, 2,6-difluoro-, and 2,3,4,5,6-pentafluorophenylnitrene in inert solvents are 5.3 +/- 0.3, 5.5 +/- 0.3, 6.7 +/- 0.3, 8.0 +/- 1.5, and 8.8 +/- 0.4 kcal/mol, respectively. The barrier to cyclization of parent singlet phenylnitrene is 5.6 +/- 0.3 kcal/mol. All of these values are in good quantitative agreement with CASPT2 calculations of the relative barrier heights for the conversion of fluoro-substituted singlet aryl nitrenes to benzazirines (Karney, W. L. and Borden, W. T. J. Am. Chem. Soc. 1997, 119, 3347). A single ortho-fluorine substituent exerts a small but significant bystander effect on remote cyclization that is not steric in origin. The influence of two ortho-fluorine substituents on the cyclization is pronounced. In the case of the singlet 2-fluorophenylnitrene system, evidence is presented that the benzazirine is an intermediate and that the corresponding singlet nitrene and benzazirine interconvert. Ab initio calculations at different levels of theory on a series of benzazirines, their isomeric ketenimines, and the transition

Characterization of reactive intermediates in laser photolysis of nucleoside using of sodium salt anthraquinone-2-sulfonic acid as photosensitizer

International Nuclear Information System (INIS)

Ma Jianhua; Lin Weizhen; Wang Wenfeng; Han Zhenhui; Yao Side; Lin Nianyun

1999-01-01

The interaction of triplet state of sodium salt of anthraquinone-2-sulfonic acid (AQS) with nucleosides has been investigated in CH 3 CN using KrF(248 nm) laser flash photolysis. The transient absorption spectra and kinetics obtained from the interaction of triplet AQS and nucleoside demonstrated that the primary ionic radical pair, radical cation of nucleosides and radical anion of AQS has been detected simultaneously for the first time

Photolysis of petroleum

International Nuclear Information System (INIS)

Bobra, M.

1992-05-01

A study was conducted to examine the chemical and physical changes that occur in oils as a result of photooxidation. A literature review of recent studies in petroleum photochemistry revealed reported effects of photo-induced reactions in petroleum, including changes in color, polymerization, solidification, increases in solubility and toxicity, and changes in interfacial properties. A list of products reported as a result of photolysis of petroleum is presented, including such compounds as aldehydes, ketones, esters, and lactones. The photoreactivity of various petroleum components is discussed and mechanisms of photooxidation of petroleum are suggested. In the experimental portion of the study, a variety of crude oils and petroleum products were used to determine how different oils are affected by photolysis, and to examine the importance of photolysis as a weathering process. Photooxidation products from several oils were isolated and identified, including aliphatic and aromatic acids, alcohols, and phenols. Some physical manifestations attributed to photolysis included yellowing, formation of precipitates or crusts, increases in density and viscosity with time, increases of asphaltene content in some oils, changes in pH of the surrounding water, and emulsification. 51 refs., 38 figs., 18 tabs

Flash Kα radiography of laser-driven solid sphere compression for fast ignition

International Nuclear Information System (INIS)

Sawada, H.; Lee, S.; Nagatomo, H.; Arikawa, Y.; Nishimura, H.; Ueda, T.; Shigemori, K.; Fujioka, S.; Shiroto, T.; Ohnishi, N.; Sunahara, A.; Beg, F. N.; Theobald, W.; Pérez, F.; Patel, P. K.

2016-01-01

Time-resolved compression of a laser-driven solid deuterated plastic sphere with a cone was measured with flash Kα x-ray radiography. A spherically converging shockwave launched by nanosecond GEKKO XII beams was used for compression while a flash of 4.51 keV Ti Kα x-ray backlighter was produced by a high-intensity, picosecond laser LFEX (Laser for Fast ignition EXperiment) near peak compression for radiography. Areal densities of the compressed core were inferred from two-dimensional backlit x-ray images recorded with a narrow-band spherical crystal imager. The maximum areal density in the experiment was estimated to be 87 ± 26 mg/cm"2. The temporal evolution of the experimental and simulated areal densities with a 2-D radiation-hydrodynamics code is in good agreement.

Flash Kα radiography of laser-driven solid sphere compression for fast ignition

Energy Technology Data Exchange (ETDEWEB)

Sawada, H. [Department of Physics, University of Nevada Reno, Reno, Nevada 89557 (United States); Lee, S.; Nagatomo, H.; Arikawa, Y.; Nishimura, H.; Ueda, T.; Shigemori, K.; Fujioka, S. [Institute of Laser Engineering, Osaka University, Suita, Osaka (Japan); Shiroto, T.; Ohnishi, N. [Department of Aerospace Engineering, Tohoku University, Sendai, Miyagi (Japan); Sunahara, A. [Institute of Laser Technology, Nishi-ku, Osaka (Japan); Beg, F. N. [University of California San Diego, La Jolla, California 92093 (United States); Theobald, W. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Pérez, F. [LULI, Ecole Polytechnique, Palaiseau, Cedex (France); Patel, P. K. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2016-06-20

Time-resolved compression of a laser-driven solid deuterated plastic sphere with a cone was measured with flash Kα x-ray radiography. A spherically converging shockwave launched by nanosecond GEKKO XII beams was used for compression while a flash of 4.51 keV Ti Kα x-ray backlighter was produced by a high-intensity, picosecond laser LFEX (Laser for Fast ignition EXperiment) near peak compression for radiography. Areal densities of the compressed core were inferred from two-dimensional backlit x-ray images recorded with a narrow-band spherical crystal imager. The maximum areal density in the experiment was estimated to be 87 ± 26 mg/cm{sup 2}. The temporal evolution of the experimental and simulated areal densities with a 2-D radiation-hydrodynamics code is in good agreement.

Flash photolysis of chlorine dioxide in aqueous solution

International Nuclear Information System (INIS)

Mialocq, Jean-Claude

1972-01-01

The primary process when aqueous solutions of chlorine dioxide are flash photo-lysed by light with a wave length greater than 270 nm is: OClO → hν ClO ( 2 Π) + O ( 3 P). The photochemical decomposition is characterized by the formation of small quantities of O ( 3 P) atoms and of equal amounts of chlorine atoms and molecular oxygen, the latter originating in the reaction: ClOO → Cl + O 2 . The isomer ClOO is formed by the germinate recombination of ClO and O, a process which is twice as important as diffusion of the fragments into the mass of the solution and one which represents 30 per cent of the decomposition of the chlorine dioxide. Under our experimental conditions, the lifetime of the ClOO is less than one microsecond. Chlorine atoms are precursors of Cl 2 O 2 , whose UV absorption spectrum has been determined, and which is formed by the reactions: Cl + OClO → Cl 2 O 2 ; Cl + Cl - → Cl 2- ; Cl 2- + OClO → Cl 2 O 2 + Cl - k = (1,0 ±0,1) 10 9 M -1 s -1 . Cl 2 O 2 disappears by a first-order process which leads to the formation of the ions Cl - and ClO 3 - . Competition between the reactions: O ( 3 P) + O 2 → O 3 ; O ( 3 P) + OClO → ClO 3 . ( k OClO + O)/( k O 2 + O) = 1.85±0.25 has been studied and the molar extinction coefficient of ClO 3 determined at its absorption maximum (255 nm): ε 255 nm = (920 ± 90) M -1 cm -1 . (author) [fr

Reactions of uranium hexafluoride photolysis products

Science.gov (United States)

Lyman, John L.; Laguna, Glenn; Greiner, N. R.

1985-01-01

This paper confirms that the ultraviolet photolysis reactions of UF6 in the B band spectral region is simple bond cleavage to UF5 and F. The photolysis products may either recombine to UF6 or the UF5 may dimerize, and ultimately polymerize, to solid UF5 particles. We use four methods to set an upper limit for the rate constant for recombination of krUF6 and UF5 after laser photolysis of the UF6 gas sample.

Photochemical primary process of photo-Fries rearrangement reaction of 1-naphthyl acetate as studied by MFE probe.

Science.gov (United States)

Gohdo, Masao; Takamasu, Tadashi; Wakasa, Masanobu

2011-01-14

Photo-Fries rearrangement reactions of 1-naphthyl acetate (NA) in n-hexane and in cyclohexane were studied by the magnetic field effect probe (MFE probe) under magnetic fields (B) of 0 to 7 T. Transient absorptions of the 1-naphthoxyl radical, T-T absorption of NA, and a short-lifetime intermediate (τ = 24 ns) were observed by a nanosecond laser flash photolysis technique. In n-hexane, the yield of escaped 1-naphthoxyl radicals dropped dramatically upon application of a 3 mT field, but then the yield increased with increasing B for 3 mT < B≤ 7 T. These observed MFEs can be explained by the hyperfine coupling and the Δg mechanisms through the singlet radical pair. The fact that MFEs were observed for the present photo-Fries rearrangement reaction indicates the presence of a singlet radical pair intermediate with a lifetime as long as several tens of nanoseconds.

Kinetics of polymer degradation in solution. 6. Laser flash photolysis and pulse radiolysis studies of polymethylvinylketone in solution using the light scattering detection method

Energy Technology Data Exchange (ETDEWEB)

Lindenau, D; Beavan, S W; Beck, G; Schnabel, W [Hahn-Meitner-Institut fuer Kernforschung Berlin G.m.b.H. (Germany, F.R.)

1977-01-01

Polymethylvinylketone (PMVK) was irradiated in solution with 2 ..mu..s pulses of 15 MeV electrons or with 15 ns flashes of 262 nm light. The change of the intensity of the light scattered by the solution (LSI) after the irradiation was measured. For the radiolysis experiments, a main chain scission process tausub(1/2) (decr) approximately 20 ..mu..s) and a subsequent crosslinking process (tausub(1/2) (incr) approximately 0.4 sec) could be discriminated. The LSI change pertaining to the main chain degradation was found to be due to disentanglement diffusion, whereas the LSI change pertaining to the crosslinking process could be correlated to a chemical reaction. The rate constant for combination of lateral macroradicals in acetone solution was estimated as 2 k/sub 2/ - (4.5 +- 1.5)10/sup 6/ M/sup -1/ sec/sup -1/. Stationary irradiation with /sup 60/Co-..gamma..-rays showed that PMVK is predominantly crosslinked to form a macrogel when irradiated in the solid state or in solution at concentrations greater than 100 g/l. At lower concentrations, microgel formation occurred. Photolysis of PMVK in solution yielded only main chain degradation. The LSI change was found to be due to disentanglement diffusion as during radiolysis. It was concluded that the same mechanism for main chain rupture is operative as in radiolysis. Stationary irradiations with uv light (lambda > 260 nm ) resulted in main chain degradation; no indication of crosslinking was obtained.

Interfacial charge recombination via the triplet state? Mimicry of photoprotection in the photosynthetic process with a dye-sensitized TiO 2 solar cell reaction

Science.gov (United States)

Weng, Yu-Xiang; Li, Long; Liu, Yin; Wang, Li; Yang, Guo-Zhen; Sheng, Jian-Qun

2002-04-01

Evidence for the photoinduced charge recombination to the excited-triplet state has been observed in chemical solar cell reaction consisting of dye-sensitized TiO 2 colloidal ethanol solution, which mimicks the photoprotection function in the photosynthetic units. The dye is all -trans-retinoic acid, a structural analog of β-carotenoid. Two channels of charge recombination, i.e., through triplet and ground states were observed by nano-second flash photolysis. The possibility of applying the function of photoprotection to the synthetic solar cell is discussed, which provides a potential entry of molecular engineering of the dye to improve the long term stability of the synthetic solar cell.

Sphinx, the high speed flash radiography; Sphinx, la radiographie eclair a grande vitesse

Energy Technology Data Exchange (ETDEWEB)

Anon.

1997-06-01

Sphinx (Nanosecond Pulse X-Photon Source) is the most compact (0.1 m{sup 3}) existing system which can generates short pulses (10 to 30 nanoseconds) of 5 to 180 keV X-photon radiation with a repeating cadence of 100 pulses per second and doses which can reach 2 mR at 1 m. This system was developed by the Research Group on Energetics of Ionized Media (GREMI) from the CNRS (French National Center for Scientific Research) and the University of Orleans (France). Sphinx is the smallest device from a series of compact X-ray sources ranging from 5 to 400 keV. These devices can have several possible applications such as the study of ultra-fast phenomena, the high cadence flash radiography in medicine, biology, materials studies, pre-ionizing of gas lasers, self-excitation and photo-ionization of atoms, molecules or aggregates. (J.S.).

Nanosecond neutron generator

International Nuclear Information System (INIS)

Lobov, S.I.; Pavlovskaya, N.G.; Pukhov, S.P.

1991-01-01

High-voltage nanosecond neutron generator for obtaining neutrons in D-T reaction is described. Yield of 6x10 6 neutron/pulse was generated in a sealed gas-filled diode with a target on the cathode by accelerating pulse voltage of approximately 0.5 MV and length at half-height of 0.5 ns and deuterium pressure of 6x10 -2 Torr. Ways of increasing neutron yield and possibilities of creating generators of nanosecond neutron pulses with great service life are considered

Updates to In-Line Calculation of Photolysis Rates

Science.gov (United States)

How photolysis rates are calculated affects ozone and aerosol concentrations predicted by the CMAQ model and the model?s run-time. The standard configuration of CMAQ uses the inline option that calculates photolysis rates by solving the radiative transfer equation for the needed ...

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.

Fulvic Acid Mediated Photolysis of Ibuprofen in Water.

Science.gov (United States)

Photolysis of the nonsteroidal anti-inflammatory drug ibuprofen was studied in solutions of fulvic acid (FA) isolated from Pony Lake, Antarctica; Suwannee River, GA, USA; and Old Woman Creek, OH, USA. At an initial concentration of 10 µM ibuprofen degrades by direct photolysis...

Optical inhomogeneity developing in flashlamp photolysis lasers

Energy Technology Data Exchange (ETDEWEB)

Alekhin, B V; Borovkov, V V; Brodskii, A Ya; Lazhintsev, B V; Nor-Arevian, V A; Sukhanov, L V

1980-07-01

The paper discusses the dynamics of optical inhomogenity developing in the active medium of a high-power flashlamp-pumped photolysis laser in inverse population storage, fast inversion suppression, and free-running lasing regimes. A chemical component of the refractive index was found in a C3F7I photolysis experiment, along with the anomalous growth of a gas refractive index.

Direct photolysis of polycyclic aromatic hydrocarbons in drinking water sources

International Nuclear Information System (INIS)

Sanches, S.; Leitao, C.; Penetra, A.; Cardoso, V.V.; Ferreira, E.; Benoliel, M.J.; Crespo, M.T. Barreto; Pereira, V.J.

2011-01-01

Highlights: → Low pressure UV photolysis can be used by drinking water utilities to degrade PAHs. → Real water matrices with different compositions were tested. → Photolysis kinetic parameters and by-product formation are described. → 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 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.

Selective laser photolysis of simple molecules

International Nuclear Information System (INIS)

Golnabi, Hossein.

1984-01-01

A two-photon technique is reported for the measurement of relative cross section for the photolysis of simple molecules into particular product channels. In this method two independently tunable dye lasers were used to sequentially dissociate molecules of Cs 2 and Cs-Kr for the wavelengths in the range 420 to 660 nm, and then to excite the resulting products to determine the relative cross sections for the photolysis of Cs 2 and Cs-kr into each of the lowest four of the energetically possible product states

Flash photolysis of cutinase

DEFF Research Database (Denmark)

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

2009-01-01

Aromatic amino acids play an important role in ultraviolet (UV)-induced photochemical reactions in proteins. In this work, we aim at gaining insight into the photochemical reactions induced by near-UV light excitation of aromatic residues that lead to breakage of disulfide bridges in our model en...... of the formed species and their lifetimes is important for the understanding of UV-induced reactions in humans that lead to light-induced diseases, e.g., skin cancer and cataract formation.......Aromatic amino acids play an important role in ultraviolet (UV)-induced photochemical reactions in proteins. In this work, we aim at gaining insight into the photochemical reactions induced by near-UV light excitation of aromatic residues that lead to breakage of disulfide bridges in our model...... of RSSR *-. Additional mechanisms that may lead to the near disappearance of Trp(*) are discussed. Our study provides insight into one key UV-light-induced reaction in cutinase, i.e., light-induced disruption of disulphide bridges mediated by the excitation of aromatic residues. Knowledge about the nature...

Verification of RDX Photolysis Mechanism

National Research Council Canada - National Science Library

Peyton, Gary

1999-01-01

... such as formaldehyde and formic acid, as well as the inorganic ions nitrate and nitrite. This implies that UV photolysis might provide a satisfactory and economical treatment system for RDX in water...

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.

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

International Nuclear Information System (INIS)

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

2015-01-01

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

Solvent effects on the photochemistry of dimethyl sulfoxide-Cl complexes studied by combined pulse radiolysis and laser flash photolysis

International Nuclear Information System (INIS)

Sumiyoshi, Takashi; Minegishi, Hideki; Fujiyoshi, Ryoko; Sawamura, Sadashi

2006-01-01

Photolysis of complexes of dimethyl sulfoxide (DMSO) with chlorine atoms results in rapid and permanent photobleaching which may be due to intramolecular hydrogen abstraction. The effects of solvent polarity were examined in a wide variety of DMSO-carbon tetrachloride mixed solvents. The quantum yields of photobleaching decreased from 0.27 to 0.08 as the solvent polarity increased, while significant changes were observed in the low DMSO concentration range ( -3 ). This cannot be accounted for by simple solvent polarity effects. The effects of polar and nonpolar additives were also examined and it is concluded that the specific solvation effect of DMSO was the main cause of the significant change in quantum yields in the low concentration range of DMSO

Electric field measurements in a dielectric barrier nanosecond pulse discharge with sub-nanosecond time resolution

International Nuclear Information System (INIS)

Goldberg, Benjamin M; Shkurenkov, Ivan; Adamovich, Igor V; Lempert, Walter R; O’Byrne, Sean

2015-01-01

The paper presents the results of time-resolved electric field measurements in a nanosecond discharge between two plane electrodes covered by dielectric plates, using picosecond four-wave mixing diagnostics. For absolute calibration, the IR signal was measured in hydrogen at a pressure of 440 Torr, for electrostatic electric field ranging from 0 to 8 kV cm −1 . The calibration curve (i.e. the square root of IR signal intensity versus electric field) was shown to be linear. By measuring the intensities of the pump, Stokes, and IR signal beam for each laser shot during the time sweep across the high-voltage pulse, temporal evolution of the electric field in the nanosecond pulse discharge was determined with sub-nanosecond time resolution. The results are compared to kinetic modeling predictions, showing good agreement, including non-zero electric field offset before the main high voltage pulse, breakdown moment, and reduction of electric field in the plasma after breakdown. The difference between the experimental results and model predictions is likely due to non-1D structure of the discharge. Comparison with the kinetic modeling predictions shows that electric field in the nanosecond pulse discharge is controlled primarily by electron impact excitation and charge accumulation on the dielectric surfaces. (paper)

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

DEFF Research Database (Denmark)

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

2014-01-01

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...... 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...

Observers can reliably identify illusory flashes in the illusory flash paradigm

NARCIS (Netherlands)

Erp, J.B.F. van; Philippi, T.G.; Werkhoven, P.

2013-01-01

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

Hot Flashes

Science.gov (United States)

Hot flashes Overview Hot flashes are sudden feelings of warmth, which are usually most intense over the face, neck and chest. Your skin might redden, as if you're blushing. Hot flashes can also cause sweating, and if you ...

Laboratory study of nitrate photolysis in Antarctic snow

DEFF Research Database (Denmark)

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

2014-01-01

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 (δ 15N, δ 18O, and Δ 17O). From these measurements an average photolytic isotopic fractionation of 15ε = (- 15 ± 1.2)‰ was found for broadband Xe lamp photolysis. These results are due in part to excitation...

Low charge state heavy ion production with sub-nanosecond laser.

Science.gov (United States)

Kanesue, T; Kumaki, M; Ikeda, S; Okamura, M

2016-02-01

We have investigated laser ablation plasma of various species using nanosecond and sub-nanosecond lasers for both high and low charge state ion productions. We found that with sub-nanosecond laser, the generated plasma has a long tail which has low charge state ions determined by an electrostatic ion analyzer even under the laser irradiation condition for highly charged ion production. This can be caused by insufficient laser absorption in plasma plume. This property might be suitable for low charge state ion production. We used a nanosecond laser and a sub-nanosecond laser for low charge state ion production to investigate the difference of generated plasma using the Zirconium target.

Low charge state heavy ion production with sub-nanosecond laser

Energy Technology Data Exchange (ETDEWEB)

Kanesue, T., E-mail: tkanesue@bnl.gov; Okamura, M. [Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973 (United States); Kumaki, M. [Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198 (Japan); Ikeda, S. [Nishina Center for Accelerator-Based Science, RIKEN, Saitama 351-0198 (Japan); Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Kanagawa 226-8503 (Japan)

2016-02-15

We have investigated laser ablation plasma of various species using nanosecond and sub-nanosecond lasers for both high and low charge state ion productions. We found that with sub-nanosecond laser, the generated plasma has a long tail which has low charge state ions determined by an electrostatic ion analyzer even under the laser irradiation condition for highly charged ion production. This can be caused by insufficient laser absorption in plasma plume. This property might be suitable for low charge state ion production. We used a nanosecond laser and a sub-nanosecond laser for low charge state ion production to investigate the difference of generated plasma using the Zirconium target.

Gas Discharge Produced by Strong Microwaves of Nanosecond Duration

International Nuclear Information System (INIS)

Vikharev, A.L.

2000-01-01

The results of the investigation of nanosecond microwave discharge are reviewed. Nanosecond microwave discharge is a new branch of gas discharge physics. The paper lists base types of microwave generators used to produce nanosecond discharge and classifies the discharges relative to their base parameters: the way the discharge gets localized in a limited space, amplitude and frequency of microwave field, gas pressure, duration of microwave pulses. The laboratory experiments performed and the new effects which appear in nanosecond microwave discharge are briefly summarized. Different applications of such a discharge are analyzed on the basis of the experimental modelling. (author)

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.

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

International Nuclear Information System (INIS)

Yang, Lihui; Zhang, Yongming; Bai, Qi; Yan, Ning; Xu, Hua; Rittmann, Bruce E.

2015-01-01

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

Preliminary studies on photolysis of polychlorinated dibenzo-p-dioxins on soils surface

Energy Technology Data Exchange (ETDEWEB)

Kobara, Y.; Ishihara, S.; Ohtsu, K.; Horio, T.; Endo, S.

2002-07-01

Polychlorinated dibenzo-p-dioxins (PCDDs) and di benzofurans (PCDFs) are ubiquitous environmental contaminants, and widely distributed in air, water and soil. They are persistent in the environmental and accumulate in living organisms. Some of these compounds are extremely toxic and carcinogenic to animals and possible humans. The Occurrence of PCDDs/PCDFs in the environment originated from both natural and anthropogenic sources. Anthropogenic sources are not manufactured for commercial purposes. These toxic compounds, however, are formed as unintentional by-products from chemical impurities in various industrial processes involving chlorine or by burning organic matter in the presence of chlorine molecules. A significant portion of PCDDs accumulated in soils in Japanese paddy fields was shown to have originated from agrochemicals, especially pentachlorophenol (PCP) and chloronitorofen (2, 4, 6-trichlorophenyl-4-nitrophenyl ether, CNP). Their impurities of PCP were mostly highly chlorinated congeners, especially OCDD that currently remains to the level of 20,000 pg/g in paddy soils. Compounds such as PCDDs/PCDFs that absorbed UV/Vis light can react photochemically by reaching excited state through the direct absorption of light (direct photolysis) or by accepting energy from an excited donor molecule (sensitized photolysis). Reactions can also occur with reactive oxygen species such as singlet oxygen, hydroxyl radicals, etc. formed from photochemical interactions with other organic molecules such as humic acids. Direct photolysis is the only mechanism for photolysis of organic chemicals in pure water and hydrocarbon solutions. However, PCDDs/PCDFs solubilities are extremely low in pure water. The low solubilities of these compounds in aqueous solution make photolysis experiments difficult. Therefore, in most previous studies of photolysis in aqueous solutions an acetonitrile/water mixture was used, furthermore, photolysis experiments were conducted through exposing

Redox reaction studies by nanosecond pulse radiolysis

International Nuclear Information System (INIS)

Moorthy, P.N.

1979-01-01

Free radicals are formed as intermediates in many chemical and biochemical reactions. An important type of reaction which they can undergo is a one electron or redox process. The direction and rate of such electron transfer reactions is governed by the relative redox potentials of the participating species. Because of the generally short lived nature of free radicals, evaluation of their redox potentials poses a number of problems. Two techniques are described for the experimental determination of the redox potentials of short lived species generated by either a nanosecond electron pulse or laser flash. In the first method, redox titration of the short lived species with stable molecules of known redox potential is carried out, employing the technique of fast kinetic spectrophotometry. Conversely, by the same method it is also possible to evaluate the one electron redox potentials of stable molecules by redox titration with free radicals of known redox potential produced as above. In the second method, electrochemical reduction or oxidation of the short lived species at an appropriate electrode (generally a mercury drop) is carried out at different fixed potentials, and the redox potential evaluated from the current-potential curves (polarograms). Full description of the experimental set up and theoretical considerations for interpretation of the raw data are given. The relative merits of the two methods and their practical applicability are discussed. (auth.)

FLASH Interface; a GUI for managing runtime parameters in FLASH simulations

Science.gov (United States)

Walker, Christopher; Tzeferacos, Petros; Weide, Klaus; Lamb, Donald; Flocke, Norbert; Feister, Scott

2017-10-01

We present FLASH Interface, a novel graphical user interface (GUI) for managing runtime parameters in simulations performed with the FLASH code. FLASH Interface supports full text search of available parameters; provides descriptions of each parameter's role and function; allows for the filtering of parameters based on categories; performs input validation; and maintains all comments and non-parameter information already present in existing parameter files. The GUI can be used to edit existing parameter files or generate new ones. FLASH Interface is open source and was implemented with the Electron framework, making it available on Mac OSX, Windows, and Linux operating systems. The new interface lowers the entry barrier for new FLASH users and provides an easy-to-use tool for experienced FLASH simulators. U.S. Department of Energy (DOE), NNSA ASC/Alliances Center for Astrophysical Thermonuclear Flashes, U.S. DOE NNSA ASC through the Argonne Institute for Computing in Science, U.S. National Science Foundation.

[Mechanism of ablation with nanosecond pulsed electric field].

Science.gov (United States)

Cen, Chao; Chen, Xin-hua; Zheng, Shu-sen

2015-11-01

Nanosecond pulsed electric field ablation has been widely applied in clinical cancer treatment, while its molecular mechanism is still unclear. Researchers have revealed that nanosecond pulsed electric field generates nanopores in plasma membrane, leading to a rapid influx of Ca²⁺; it has specific effect on intracellular organelle membranes, resulting in endoplasmic reticulum injuries and mitochondrial membrane potential changes. In addition, it may also change cellular morphology through damage of cytoskeleton. This article reviews the recent research advances on the molecular mechanism of cell membrane and organelle changes induced by nanosecond pulsed electric field ablation.

Diphosphine is an intermediate in the photolysis of phosphine to phosphorus and hydrogen

Energy Technology Data Exchange (ETDEWEB)

Ferris, J P; Benson, R [Rensselaer Polytechnic Inst., Troy, NY (USA). Dept. of Chemistry

1980-05-15

Photolysis of phosphine (PH/sub 3/) has been investigated because of its potential significance in the atmosphere chemistry of Jupiter. It is reported that P/sub 2/H/sub 4/is the initial product of PH/sub 3/ photolysis and that it is the principal intermediate in the formation of red phosphorus. It is stated that these findings require substantial revision of the previously accepted mechanism for PH/sub 3/ photolysis.

Flash Platform Examination

Science.gov (United States)

2011-03-01

than would be performed in software”[108]. Uro Tinic, one of the Flash player’s engineers, further clarifies exactly what Flash player 10 hardware...www.adobe.com/products/flashplayer/features/ (Access date: 28 Sep 2009). [109] Uro , T. What Does GPU Acceleration Mean? (online), http...133] Shorten, A. (2009), Design to Development: Flash Catalyst to Flash Builder, In Proceedings of Adobe Max 2009, Los Angeles, CA. 142 DRDC

Photolysis of O-nitrobenzoin: a reinvestigation

International Nuclear Information System (INIS)

Dicks, P.F.; Goosen, A.; McCleland, C.W.

1983-01-01

Photolysis of O-nitrobenzoin produces benzaldehyde and 2-phenylbenzo[b]furan. The addition of a nitrogen dioxide scavenger and a triplet n→πsup(*) carbonyl quencher are shown to inhibit 2-phenylbenzo[b]furan formation. It is proposed that cyclization occurs through the carbonyl n→πsup(*) triplet state. The benzaldehyde could result either from rapid α-cleavage of the carbonyl group, occurring from either the singlet or triplet n→πsup(*) states in a process which is concerted with cleavage of the O-NO 2 bond, or from fragmentation of the alkoxyl radical produced upon photolysis of the nitrate ester, or from a combination of both processes. Support for the intermediacy of the alkoxyl radical is afforded by the observation that O-nitro-hydrobenzoin and some of its derivatives all afforded benzaldehyde under similar conditions

Development of Ultrafast Laser Flash Methods for Measuring Thermophysical Properties of Thin Films and Boundary Thermal Resistances

Science.gov (United States)

Baba, Tetsuya; Taketoshi, Naoyuki; Yagi, Takashi

2011-11-01

Reliable thermophysical property values of thin films are important to develop advanced industrial technologies such as highly integrated electronic devices, phase-change memories, magneto-optical disks, light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), semiconductor lasers (LDs), flat-panel displays, and power electronic devices. In order to meet these requirements, the National Metrology Institute of Japan of the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) has developed ultrafast laser flash methods heated by picosecond pulse or nanosecond pulse with the same geometrical configuration as the laser flash method, which is the standard method to measure the thermal diffusivity of bulk materials. Since these pulsed light heating methods induce one-dimensional heat diffusion across a well-defined length of the specimen thickness, the absolute value of thermal diffusivity across thin films can be measured reliably. Using these ultrafast laser flash methods, the thermal diffusivity of each layer of multilayered thin films and the boundary thermal resistance between the layers can be determined from the observed transient temperature curves based on the response function method. The thermophysical properties of various thin films important for modern industries such as the transparent conductive films used for flat-panel displays, hard coating films, and multilayered films of next-generation phase-change optical disks have been measured by these methods.

Nanosecond high-power dense microplasma switch for visible light

Energy Technology Data Exchange (ETDEWEB)

Bataller, A., E-mail: bataller@physics.ucla.edu; Koulakis, J.; Pree, S.; Putterman, S. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095 (United States)

2014-12-01

Spark discharges in high-pressure gas are known to emit a broadband spectrum during the first 10 s of nanoseconds. We present calibrated spectra of high-pressure discharges in xenon and show that the resulting plasma is optically thick. Laser transmission data show that such a body is opaque to visible light, as expected from Kirchoff's law of thermal radiation. Nanosecond framing images of the spark absorbing high-power laser light are presented. The sparks are ideal candidates for nanosecond, high-power laser switches.

Utilization of solar energy through photosynthesis and artificial water photolysis

International Nuclear Information System (INIS)

Broda, E.

1976-01-01

The plants build up organic matter with a carbon content of the order of 1011 t/year by means of photochemistry. Energy farming for the production of liquid or gaseous fuel is discussed. Yet the abiotic photolysis of water with production of hydrogen is preferable. By means of synthetic, asymmetric, photochemically active, membranes the primary products of water photolysis could be spatially separated so that their recombination is prevented.(author)

The haptic and the visual flash-lag effect and the role of flash characteristics.

Directory of Open Access Journals (Sweden)

Knut Drewing

Full Text Available When a short flash occurs in spatial alignment with a moving object, the moving object is seen ahead the stationary one. Similar to this visual "flash-lag effect" (FLE it has been recently observed for the haptic sense that participants judge a moving hand to be ahead a stationary hand when judged at the moment of a short vibration ("haptic flash" that is applied when the two hands are spatially aligned. We further investigated the haptic FLE. First, we compared participants' performance in two isosensory visual or haptic conditions, in which moving object and flash were presented only in a single modality (visual: sphere and short color change, haptic: hand and vibration, and two bisensory conditions, in which the moving object was presented in both modalities (hand aligned with visible sphere, but the flash was presented only visually or only haptically. The experiment aimed to disentangle contributions of the flash's and the objects' modalities to the FLEs in haptics versus vision. We observed a FLE when the flash was visually displayed, both when the moving object was visual and visuo-haptic. Because the position of a visual flash, but not of an analogue haptic flash, is misjudged relative to a same visuo-haptic moving object, the difference between visual and haptic conditions can be fully attributed to characteristics of the flash. The second experiment confirmed that a haptic FLE can be observed depending on flash characteristics: the FLE increases with decreasing intensity of the flash (slightly modulated by flash duration, which had been previously observed for vision. These findings underline the high relevance of flash characteristics in different senses, and thus fit well with the temporal-sampling framework, where the flash triggers a high-level, supra-modal process of position judgement, the time point of which further depends on the processing time of the flash.

High-Voltage, Multiphasic, Nanosecond Pulses to Modulate Cellular Responses.

Science.gov (United States)

Ryan, Hollie A; Hirakawa, Shinji; Yang, Enbo; Zhou, Chunrong; Xiao, Shu

2018-04-01

Nanosecond electric pulses are an effective power source in plasma medicine and biological stimulation, in which biophysical responses are governed by peak power and not energy. While uniphasic nanosecond pulse generators are widely available, the recent discovery that biological effects can be uniquely modulated by reversing the polarity of nanosecond duration pulses calls for the development of a multimodal pulse generator. This paper describes a method to generate nanosecond multiphasic pulses for biomedical use, and specifically demonstrates its ability to cancel or enhance cell swelling and blebbing. The generator consists of a series of the fundamental module, which includes a capacitor and a MOSFET switch. A positive or a negative phase pulse module can be produced based on how the switch is connected. Stacking the modules in series can increase the voltage up to 5 kV. Multiple stacks in parallel can create multiphase outputs. As each stack is independently controlled and charged, multiphasic pulses can be created to produce flexible and versatile pulse waveforms. The circuit topology can be used for high-frequency uniphasic or biphasic nanosecond burst pulse production, creating numerous opportunities for the generator in electroporation applications, tissue ablation, wound healing, and nonthermal plasma generation.

Energy coupling to the plasma in repetitive nanosecond pulse discharges

International Nuclear Information System (INIS)

Adamovich, Igor V.; Nishihara, Munetake; Choi, Inchul; Uddi, Mruthunjaya; Lempert, Walter R.

2009-01-01

A new analytic quasi-one-dimensional model of energy coupling to nanosecond pulse discharge plasmas in plane-to-plane geometry has been developed. The use of a one-dimensional approach is based on images of repetitively pulsed nanosecond discharge plasmas in dry air demonstrating that the plasma remains diffuse and uniform on a nanosecond time scale over a wide range of pressures. The model provides analytic expressions for the time-dependent electric field and electron density in the plasma, electric field in the sheath, sheath boundary location, and coupled pulse energy. The analytic model predictions are in very good agreement with numerical calculations. The model demonstrates that (i) the energy coupled to the plasma during an individual nanosecond discharge pulse is controlled primarily by the capacitance of the dielectric layers and by the breakdown voltage and (ii) the pulse energy coupled to the plasma during a burst of nanosecond pulses decreases as a function of the pulse number in the burst. This occurs primarily because of plasma temperature rise and resultant reduction in breakdown voltage, such that the coupled pulse energy varies approximately proportionally to the number density. Analytic expression for coupled pulse energy scaling has been incorporated into the air plasma chemistry model, validated previously by comparing with atomic oxygen number density measurements in nanosecond pulse discharges. The results of kinetic modeling using the modified air plasma chemistry model are compared with time-resolved temperature measurements in a repetitively pulsed nanosecond discharge in air, by emission spectroscopy, and purely rotational coherent anti-Stokes Raman spectroscopy showing good agreement.

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

Atmospheric degradation of 2- nitrobenzaldehyde: Photolysis and reaction with OH radicals

Science.gov (United States)

Bouya, H.; Al Rashidi, M.; Roth, E.; Salghi, R.; Chakir, A.

2017-12-01

This work presents an experimental study of the gas phase kinetics of 2-nitrobenzaldehyde (2-NBA) photolysis and oxidation by OH radicals. The experiments were carried out in an atmospheric simulation chamber coupled to an FTIR spectrometer and CG/MS. The UV spectra of 2-NBA were also measured and the experimentally determined absorption cross sections were used to estimate the atmospheric photo-dissociation constant of 2-NBA with a global quantum yield of 0.5. The obtained results indicate that 2-NBA is a highly photolysable. A mechanism of 2-NBA photolysis was proposed based on the identification of photolysis degradation products. The kinetics of oxidation of 2-NBA by OH radicals was investigated over the temperature range 308-352 K. The obtained rate coefficients exhibits slight negative temperature dependence and the Arrhenius expression obtained is as follows: kOH+2-NBA(T)= (7.00 ± 3.40) × 10-12exp (577 ± 156/T) cm3 molecule-1 s-1. The calculated rate coefficients lead to tropospheric lifetimes of 2-NBA that are in the order of a few minutes, relative to photolysis, or a few hours, relative to oxidation by OH radicals.

Energy efficiency in nanoscale synthesis using nanosecond plasmas.

Science.gov (United States)

Pai, David Z; Ken Ostrikov, Kostya; Kumar, Shailesh; Lacoste, Deanna A; Levchenko, Igor; Laux, Christophe O

2013-01-01

We report a nanoscale synthesis technique using nanosecond-duration plasma discharges. Voltage pulses 12.5 kV in amplitude and 40 ns in duration were applied repetitively at 30 kHz across molybdenum electrodes in open ambient air, generating a nanosecond spark discharge that synthesized well-defined MoO₃ nanoscale architectures (i.e. flakes, dots, walls, porous networks) upon polyamide and copper substrates. No nitrides were formed. The energy cost was as low as 75 eV per atom incorporated into a nanostructure, suggesting a dramatic reduction compared to other techniques using atmospheric pressure plasmas. These findings show that highly efficient synthesis at atmospheric pressure without catalysts or external substrate heating can be achieved in a simple fashion using nanosecond discharges.

Photolysis of polycyclic aromatic hydrocarbons adsorbed on spruce [Picea abies (L.) Karst.] needles under sunlight irradiation

International Nuclear Information System (INIS)

Niu Junfeng; Chen Jingwen; Martens, D.; Quan Xie; Yang Fenglin; Kettrup, A.; Schramm, K.-W.

2003-01-01

Photolysis of PAHs on surfaces may determine their ultimate fate in the environment. - Photolysis of polycyclic aromatic hydrocarbons (PAHs) sorbed on surfaces of spruce [Picea abies (L.) Karst.] needles under sunlight irradiation was investigated. PAHs were produced by combustion of polyvinyl chloride (PVC), wood, high-density polyethylene (HDPE), and styrene in a stove. The factors of sunlight irradiation on the surfaces of spruce needles were taken into consideration when investigating the kinetic parameters. The photolysis of the 18 PAHs under study follows first-order kinetics. The photolysis half-lives range from 15 h for dibenzo(a,h)anthracene to 75 h for phenanthrene. Photolysis of some PAHs on surfaces of spruce needles may play an important role on the fate of PAHs in the environment

Flash!

Science.gov (United States)

Schilling, Govert

2002-04-01

About three times a day our sky flashes with a powerful pulse of gamma ray bursts (GRB), invisible to human eyes but not to astronomers' instruments. The sources of this intense radiation are likely to be emitting, within the span of seconds or minutes, more energy than the sun will in its entire 10 billion years of life. Where these bursts originate, and how they come to have such incredible energies, is a mystery scientists have been trying to solve for three decades. The phenomenon has resisted study -- the flashes come from random directions in space and vanish without trace -- until very recently. In what could be called a cinematic conflation of Flash Gordon and The Hunt for Red October, Govert Schilling's Flash!: The Hunt for the Biggest Explosions in the Universe describes the exciting and ever-changing field of GRB research. Based on interviews with leading scientists, Flash! provides an insider's account of the scientific challenges involved in unravelling the enigmatic nature of GRBs. A science writer who has followed the drama from the very start, Schilling describes the ambition and jealousy, collegiality and competition, triumph and tragedy, that exists among those who have embarked on this recherche. Govert Schilling is a Dutch science writer and astronomy publicist. He is a contributing editor of Sky and Telescope magazine, and regularly writes for the news sections of Science and New Scientist. Schilling is the astronomy writer for de Volkskrant, one of the largest national daily newspapers in The Netherlands, and frequently talks about the Universe on Dutch radio broadcasts. He is the author of more than twenty popular astronomy books, and hundreds of newspaper and magazine articles on astronomy.

Photolysis of rhodamine-WT dye

Science.gov (United States)

Tai, D.Y.; Rathbun, R.E.

1988-01-01

Photolysis of rhodamine-WT dye under natural sunlight conditions was determined by measuring the loss of fluorescence as a function of time. Rate coefficients at 30?? north latitude ranged from 4.77 x 10-2 day-1 for summer to 3.16 x 10-2 day-1 for winter. Experimental coefficients were in good agreement with values calculated using a laboratory-determined value of the quantum yield.

Photolysis of nonylphenol ethoxylates: the determination of the degradation kinetics and the intermediate products.

Science.gov (United States)

Chen, Ling; Zhou, Hai-Yun; Deng, Qin-Ying

2007-06-01

The photolysis of nonylphenol ethoxylates with an average oligomers length of ten ethoxylate units (NPEO(10)) in aqueous solution under UV, as well as the influence of humic acid (HA) on the photolysis was studied. A 125W high-pressure mercury lamp was employed as the light source. The intermediate products from the photolysis were determined by LC-MS. The results indicated that NPEO(10) underwent direct photolysis upon exposed to UV. The degradation pathway was complex. Besides the generally proposed degradation pathway of ethylene oxide (EO) side chains shortening, the oxidation of alkyl chain and EO chain led to intermediates having both a carboxylated (as well as carbonylated) ethoxylate and alkyl chain of varying lengths. The hydrogenation of benzene ring was also detected. The kinetics data showed that the first order reaction kinetics could be well used to describe the kinetics of NPEO(10) degradation. In the presence of dissolved organic matter by HA addition, the performance of NPEO(10) photodegradation was reduced. The photolysis rate decreased with increased HA concentration.

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

O2–6 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......O2–5 is formed in a reaction with the hydroxyl radical anion in which the hydroxyl radical anion adds to the xenon atom and by photolysis of HXeO3–6: HXeO3–6 [graphic omitted] HXeO2–5+ O–. XeV, XeVII and XeIX and corresponding iodine species in the oxidation states four, six and eight have similar...

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

Photolysis of low concentration H2S under UV/VUV irradiation emitted from high frequency discharge electrodeless lamps.

Science.gov (United States)

Xu, Jianhui; Li, Chaolin; Liu, Peng; He, Di; Wang, Jianfeng; Zhang, Qian

2014-08-01

The photolysis of low concentration of H2S malodorous gas was studied under UV irradiation emitted by self-made high frequency discharge electrodeless lamp with atomic mercury lines at 185/253.7nm. Experiments results showed that the removal efficiency (ηH2S) of H2S was decreased with increasing initial H2S concentration and increased slightly with gas residence time. ηH2S was increased dramatically with relative humidity from<5% to 43% while the concentration of oxygen in gas environments affected the removal of H2S. The mechanisms for direct and indirect photolysis (generation of ozone) were illustrated by the experimental results on photolysis of H2S under argon environments and ozonation of H2S under air environments, respectively. The overall ηH2S by photolysis is higher than the combination of ηH2S by direct photolysis and ozonation, suggesting that hydroxyl radical-mediated indirect photolysis played an important role during photolysis processes. The main photolysis product was confirmed to be SO4(2-) with ion chromatograph. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

One nanosecond pulsed electron gun systems

International Nuclear Information System (INIS)

Koontz, R.F.

1979-02-01

At SLAC there has been a continuous need for the injection of very short bunches of electrons into the accelerator. Several time-of-flight experiments have used bursts of short pulses during a normal 1.6 micro-second rf acceleration period. Single bunch beam loading experiments made use of a short pulse injection system which included high power transverse beam chopping equipment. Until the equipment described in this paper came on line, the basic grid-controlled gun pulse was limited to a rise time of 7 nanoseconds and a pulse width of 10 nanoseconds. The system described here has a grid-controlled rise time of less than 500 pico-seconds, and a minimum pulse width of less than 1 nanosecond. Pulse burst repetition rate has been demonstrated above 20 MHz during a 1.6 microsecond rf accelerating period. The order-of-magnitude increase in gun grid switching speed comes from a new gun design which minimizes lead inductance and stray capacitance, and also increases gun grid transconductance. These gun improvements coupled with a newly designed fast pulser mounted directly within the gun envelope make possible subnanosecond pulsing of the gun

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.

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

Science.gov (United States)

Galí, Martí; Kieber, David J; Romera-Castillo, Cristina; Kinsey, Joanna D; Devred, Emmanuel; Pérez, Gonzalo L; Westby, George R; Marrasé, Cèlia; Babin, Marcel; Levasseur, Maurice; Duarte, Carlos M; Agustí, Susana; Simó, Rafel

2016-12-20

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 m 3 (mol quanta) -1 ). In open-ocean waters, AQY(330) generally ranged between 1 and 10 m 3 (mol quanta) -1 . The largest AQY(330), up to 34 m 3 (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.

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 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...

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 ( 0.03 ar.......03 are obtained from three days of experiments for each reaction in the period June 17 to July 7, 2006.......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...

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...

Continuous Monitoring of Photolysis Products by Thz Spectroscopy

Science.gov (United States)

Omar, Abdelaziz; Cuisset, Arnaud; Mouret, Gaël; Hindle, Francis; Eliet, Sophie; Bocquet, Robin

2015-06-01

We demonstrate the potential of THz spectroscopy to monitor the real time evolution of the gas phase concentration of photolysis products and determine the kinetic reaction rate constant. In the primary work, we have chosen to examine the photolysis of formaldehyde (H_2CO). Exposure of H_2CO to a UVB light (250 to 360 nm) in a single pass of 135 cm length cell leads to decomposition via two mechanisms: the radical channel with production of HCO and the molecular channel with production of CO. A commercial THz source (frequency multiplication chain) operating in the range 600-900 GHz was used to detect and quantify the various chemical species as a function of time. Monitoring the concentrations of CO and H_2CO via rotational transitions, allowed the kinetic rate of H_2CO consummation to be obtained, and an estimation of the rate constants for both the molecular and radical photolysis mechanisms. We have modified our experimental setup to increase the sensitivity of the spectrometer and changed sample preparation protocol specifically to quantify the HCO concentration. Acetaldehyde was used as the precursor for photolysis by UVC resulting in the decompositon mechanism can be described by: CH_3CHO+hν→ CH_3 + HCO → CH_4 + CO Frequency modulation of the source and Zeeman modulation is used to achieve the high sensitivity required. Particular attention has been paid to the mercury photosensitization effect that allowed us to increase the HCO production enabling quantification of the monitored radical. We quantify the HCO radical and start a spectroscopic study of the line positions. H. M. Pickett and T. L. Boyd, Chem. Phys. Lett, Vol 58, 446-449, (1978) S. Eliet, A. Cuisset, M Guinet, F. Hindle, G. Mouret, R. Bocquet, and J. Demaison, Journal of Molecular Spectroscopy, Vol 279, 12-15 (2012). G. Mouret, M. Guinet, A. Cuisset, L. Croizé, S. Eliet, R. Bocquet and F. Hindle, Sensors Journal. IEEE, Vol 13, 133 - 138, (2013)

Photochemical of Polychlorinated biphenyl by the photolysis and ...

African Journals Online (AJOL)

Michael Horsfall

reaction mixture inside the cell was continuously stirred with a .... work on PCB photolysis was carried out in alkanes and alcohols. .... dominant mechanism of PCBs destruction becomes hydroxyl ... (2004). Using solar and ultraviolet light to.

Flash grundkursus

DEFF Research Database (Denmark)

Jensen, Henrik

2008-01-01

Flash er et programmeringssprog  og kan som sådant ikke noget i sig selv. Kursets mål er, at give den studerende et grundlæggende kendskab til Flash, så det kan bruges til præsentationer på skærm og til produktion af hjemmesider. På kurset arbejdes der med billede, grafik, lyd, video og interakti...

Prevalence and sunlight photolysis of controlled and chemotherapeutic drugs in aqueous environments

International Nuclear Information System (INIS)

Lin, Angela Yu-Chen; Lin, Yen-Ching; Lee, Wan-Ning

2014-01-01

This study addresses the occurrences and natural fates of chemotherapeutics and controlled drugs when found together in hospital effluents and surface waters. The results revealed the presence of 11 out of 16 drugs in hospital effluents, and the maximum detected concentrations were at the μg L −1 level in the hospital effluents and the ng L −1 level in surface waters. The highest concentrations corresponded to meperidine, morphine, 5-fluorouracil and cyclophosphamide. The sunlight photolysis of the target compounds was investigated, and the results indicated that morphine and codeine can be significantly attenuated, with half-lives of 0.27 and 2.5 h, respectively, in natural waters. Photolysis can lower the detected environmental concentrations, also lowering the estimated environmental risks of the target drugs to human health. Nevertheless, 5-fluorouracil and codeine were found to have a high risk quotient (RQ), demonstrating the high risks of directly releasing hospital wastewater into the environment. - Highlights: • High occurrence of chemotherapeutics and controlled substances in aqueous systems. • Photolysis lowers the detected concentrations of morphine and codeine. • 5-fluorouracil and codeine in hospital effluents have high risk quotients. - Chemotherapeutics and controlled drugs occur at significant levels in hospital effluents and surface waters. Natural sunlight photolysis reduces their environmental occurrence

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

. Reducing blindness from cataract requires solutions that can be applied outside operating theatres. Cataract is a protein conformational disease characterized by accumulation of light absorbing, fluorescent and scattering protein aggregates. The aim of the study was to investigate whether these compounds...... 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...

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.

Flashing oscillation in pool water

International Nuclear Information System (INIS)

Takamasa, Tomoji; Kondo, Koichi; Hazuku, Tatsuya

1996-01-01

This paper presents an experimental study of high-pressure saturated water discharging into the pool water. The purpose of the experiment is to clarify the phenomena that occur in blow-down of high-pressure saturated water from the pressure vessel into the water-filled containment in the case of a wall-crack accident or a LOCA in an advanced reactor. The results revealed that a flashing oscillation (FO) occurs when high-pressure saturated water discharges into the pool water, under specified experimental settings. The range of the flashing oscillates between a point very close to and some distance from the vent hole. The pressures in the vent tube and pool water vary according to the flashing oscillation. The pressure oscillation and frequency of flashing position might be caused by the balancing action between the supply of saturated water, flashing at the control volume and its condensation on the steam-water interface. A linear analysis was conducted using a spherical flashing bubble model. The period of the flashing oscillation in the experiments can be explained by theoretical analysis

Hot flashes and sleep in women.

Science.gov (United States)

Moe, Karen E

2004-12-01

Sleep disturbances during menopause are often attributed to nocturnal hot flashes and 'sweats' associated with changing hormone patterns. This paper is a comprehensive critical review of the research on the relationship between sleep disturbance and hot flashes in women. Numerous studies have found a relationship between self-reported hot flashes and sleep complaints. However, hot flash studies using objective sleep assessment techniques such as polysomnography, actigraphy, or quantitative analysis of the sleep EEG are surprisingly scarce and have yielded somewhat mixed results. Much of this limited evidence suggests that hot flashes are associated with objectively identified sleep disruption in at least some women. At least some of the negative data may be due to methodological issues such as reliance upon problematic self-reports of nocturnal hot flashes and a lack of concurrent measures of hot flashes and sleep. The recent development of a reliable and non-intrusive method for objectively identifying hot flashes during the night should help address the need for substantial additional research in this area. Several areas of clinical relevance are described, including the effects of discontinuing combined hormone therapy (estrogen plus progesterone) or estrogen-only therapy, the possibility of hot flashes continuing for many years after menopause, and the link between hot flashes and depression.

MR colonography with fecal tagging: comparison between 2D turbo FLASH and 3D FLASH sequences

International Nuclear Information System (INIS)

Papanikolaou, Nickolas; Grammatikakis, John; Maris, Thomas; Prassopoulos, Panos; Gourtsoyiannis, Nicholas; Lauenstein, Thomas

2003-01-01

The objective of this study was to compare inversion recovery turbo 2D fast low-angle shot (FLASH) and 3D FLASH sequences for fecal-tagged MR colonography studies. Fifteen consecutive patients with indications for colonoscopy underwent MR colonography with fecal tagging. An inversion recovery turbo-FLASH sequence was applied and compared in terms of artifacts presence, efficiency for masking residual stool, and colonic wall conspicuity with a fat-saturated 3D FLASH sequence. Both sequences were acquired following administration of paramagnetic contrast agent. Contrast-to-noise ratio and relative contrast between colonic wall and lumen were calculated and compared for both sequences. Turbo 2D FLASH provided fewer artifacts, higher efficiency for masking the residual stool, and colonic wall conspicuity equivalent to 3D FLASH. An inversion time of 10 ms provided homogeneously low signal intensity of the colonic lumen. Contrast to noise between colonic wall and lumen was significantly higher in the 3D FLASH images, whereas differences in relative contrast were not statistically significant. An optimized inversion-recovery 2D turbo-FLASH sequence provides better fecal tagging results and should be added to the 3D FLASH sequence when designing dark-lumen MR colonography examination protocols. (orig.)

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.

CO2 laser photolysis of clustered ions, (1)

International Nuclear Information System (INIS)

Ikezoe, Yasumasa; Soga, Takeshi; Suzuki, Kazuya; Ohno, Shin-ichi.

1990-09-01

Vibrational excitation and the following decomposition of cluster ions by CO 2 laser photons are studied. Characteristics of the cluster ion and the CO 2 laser photon are summarized in their relation to the photolysis of cluster ions. An apparatus was installed, which is composed of (1) corona discharge-jet expansion section (formation of cluster ions), (2) CO 2 laser section (photolysis of cluster ions), and (3) mass spectrometer section. Experimental results of ammonia cluster ions were described. Effects of repeller voltage, shape of repellers, and adiabatic cooling are examined on the formation of ammonia cluster ions by corona discharge-jet expansion method. Collisional dissociation of cluster ions was observed at high repeller voltages. Size distribution of the ammonia cluster ion is discussed in connection with the temperature of cluster ions. Intensity of CO 2 laser was related to decomposition yield of cluster ions. (author)

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.

Photolysis of butenedial at 193, 248, 280, 308, 351, 400, and 450 nm

Science.gov (United States)

Tang, Yongxin; Zhu, Lei

2005-06-01

We have studied the photolysis of butenedial at 193, 248, 280, 308, 351, 400, and 450 nm by using laser photolysis combined with cavity ring-down spectroscopy. The HCO radical is a photodissociation product at 193 and 248 nm. The corresponding HCO quantum yields are 0.55 ± 0.07 and 0.12 ± 0.01, independent of butenedial pressure and nitrogen buffer gas pressure. Absorption cross-sections of butenedial are (6.88 ± 0.39) × 10 -18 and (3.62 ± 0.69) × 10 -19 cm 2 at 193 and 248 nm. The end-products from the photolysis of butenedial at 193, 248, 308, and 351 nm were measured by FTIR. Acrolein and 3H-furan-2-one were observed and their yields have been estimated.

The October 2014 United States Treasury bond flash crash and the contributory effect of mini flash crashes.

Directory of Open Access Journals (Sweden)

Zachary S Levine

Full Text Available We investigate the causal uncertainty surrounding the flash crash in the U.S. Treasury bond market on October 15, 2014, and the unresolved concern that no clear link has been identified between the start of the flash crash at 9:33 and the opening of the U.S. equity market at 9:30. We consider the contributory effect of mini flash crashes in equity markets, and find that the number of equity mini flash crashes in the three-minute window between market open and the Treasury Flash Crash was 2.6 times larger than the number experienced in any other three-minute window in the prior ten weekdays. We argue that (a this statistically significant finding suggests that mini flash crashes in equity markets both predicted and contributed to the October 2014 U.S. Treasury Bond Flash Crash, and (b mini-flash crashes are important phenomena with negative externalities that deserve much greater scholarly attention.

The October 2014 United States Treasury bond flash crash and the contributory effect of mini flash crashes.

Science.gov (United States)

Levine, Zachary S; Hale, Scott A; Floridi, Luciano

2017-01-01

We investigate the causal uncertainty surrounding the flash crash in the U.S. Treasury bond market on October 15, 2014, and the unresolved concern that no clear link has been identified between the start of the flash crash at 9:33 and the opening of the U.S. equity market at 9:30. We consider the contributory effect of mini flash crashes in equity markets, and find that the number of equity mini flash crashes in the three-minute window between market open and the Treasury Flash Crash was 2.6 times larger than the number experienced in any other three-minute window in the prior ten weekdays. We argue that (a) this statistically significant finding suggests that mini flash crashes in equity markets both predicted and contributed to the October 2014 U.S. Treasury Bond Flash Crash, and (b) mini-flash crashes are important phenomena with negative externalities that deserve much greater scholarly attention.

Pulse photolysis of NADH in the presence of cysteine

International Nuclear Information System (INIS)

Scheel, H.E.

1976-01-01

In the UV irradiation of NADH under anaerobic conditions, cysteine, which often acts as a radioprotective substance, has a sensitizing effect. With the aid of pulse photolysis, it was studied which reaction mechanisms in the presence or absence of cysteine are responsible for the damage to NADH in aqueous solution. In the absence of cysteine, the characteristic NADH absorption at 340 nm is reduced immediately after UV quanta have been absorbed by the adenine fraction of the molecules; in the presence of cysteine, a secondary reaction causes additional damage. The spectra of the intermediate products of NADH and cysteine have been recorded for different cysteine concentrations, and the reaction constants have been determined. These values suggest that the sensitizing effect is due to a reaction of NADH with radical anions produced by photolysis. (orig.) [de

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

Energy Technology Data Exchange (ETDEWEB)

Yan, Caixia [School of Geography and Environment, Key Laboratory of Poyang Lake Wetland and Watershed Research, Ministry of Education, Jiangxi Normal University, No. 99, Ziyang Road, Nanchang 330022 (China); State Key Laboratory of Estuarine and Coastal Research, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); SmartState Center for Environmental Nanoscience and Risk, Arnold School of Public Health, University of South Carolina, 921 Assembly Street, Columbia 29208,USA (United States); Nie, Minghua [School of Geography and Environment, Key Laboratory of Poyang Lake Wetland and Watershed Research, Ministry of Education, Jiangxi Normal University, No. 99, Ziyang Road, Nanchang 330022 (China); Department of Environmental Science and Engineering, Fudan University, 220Handan Road, Shanghai 200433 (China); Yang, Yi, E-mail: yyang@geo.ecnu.edu.cn [State Key Laboratory of Estuarine and Coastal Research, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Key Laboratory of Geographic Information Science of the Ministry of Education, Department of Geosciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Zhou, Junliang [State Key Laboratory of Estuarine and Coastal Research, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Liu, Min [Key Laboratory of Geographic Information Science of the Ministry of Education, Department of Geosciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Baalousha, Mohammed; Lead, Jamie R. [SmartState Center for Environmental Nanoscience and Risk, Arnold School of Public Health, University of South Carolina, 921 Assembly Street, Columbia 29208,USA (United States)

2015-12-15

Highlights: • Colloidal fractions in wastewaters were isolated using cross flow ultrafiltration. • EOCs exhibited a pseudo - first - order degradation kinetics in all water samples. • Photolysis of EOCs in permeate were accelerated, while inhibited in the retentates. • EOCs with higher degradation rates were detected at low level in natural water. - Abstract: 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 (<1 μm) was separated into permeate (<1 kDa) and retentate (1 kDa-1 μm) by cross flow ultrafiltration. Results indicated that total concentration of EOCs ranged from 1220 ng L{sup −1} in permeate of DW to 5065 ng L{sup −1} in retentate of LW. The average EOC fraction associated with 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.

Photolysis of imidacloprid in aqueous solution

International Nuclear Information System (INIS)

Moza, P.N.; Hustert, K.; Feicht, E.; Kettrup, A.

1998-01-01

The photolysis of the insecticide imidacloprid in aqueous solution has been examined. Irradiation at 290 nm resulted in 90 % substrate transformation in 4 h. The degradation approximately followed first order kinetics; the rate constant is 1.6 × 10 −4 s −1 and half-life 1.2 h. 6-Chloronicotinaldehyde, N-methylnicotinacidamide, 1-(6-chloronicotinyl)imidazolidone and 6-chloro-3-pyridyl-methylethylendiamine were the main photoproducts identified by CG-MS analysis. (author)

DIRCM FLASH Flight Tests

National Research Council Canada - National Science Library

Molocher, Bernhard; Kaltenecker, Anton; Thum-Jaeger, Andrea; Regensburger, Martin; Formery, Martin

2005-01-01

.... FLASH operation is as follows: After handover following an alarm from the missile warning system FLASH enters autonomous passive tracking mode for tracking a missiles and sending a laser beam onto the missile...

Triplet states of carotenoids from photosynthetic bacteria studied by nanosecond ultraviolet and electron pulse irradiation

International Nuclear Information System (INIS)

Bensasson, R.; Land, E.J.; Maudinas, B.

1976-01-01

Absorptions of the triplet excited states of five carotenoids (15,15'-cis phytoene, all-trans phytoene, zeta-carotene, spheroidene and spirillox-anthin), extracted from the photosynthetic bacteria Rhodopseudomonas spheroides and Rhodospirillum rubrum, have been detected in solution using pulse radiolysis and laser flash photolysis. Triplet lifetimes, extinction coefficients, lowest energy levels and quantum efficiencies of formation have been determined. Comparison of the carotenoid triplet energy levels with that of O 2 ('Δsub(g)) suggests that spirilloxanthin, spheroidene and possibly also zeta-carotene, would be expected to protect against photodynamic action caused by O 2 ('Δsub(g)), but not cis or trans phytoene. The S → T intersystem crossing efficiencies of all five polyenes were found to be low, being a few per cent or less. In their protective role these triplet states can only therefore be effectively reached via energy transfer from another triplet, except in the case of O 2 (Δsub(g)). The low crossover efficiencies also mean that light absorbed in such carotenoids in their possible role as accessory pigments would not be wasted in crossing over to the triplet state. (author)

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.

Transmembrane molecular transport during versus after extremely large, nanosecond electric pulses.

Science.gov (United States)

Smith, Kyle C; Weaver, James C

2011-08-19

Recently there has been intense and growing interest in the non-thermal biological effects of nanosecond electric pulses, particularly apoptosis induction. These effects have been hypothesized to result from the widespread creation of small, lipidic pores in the plasma and organelle membranes of cells (supra-electroporation) and, more specifically, ionic and molecular transport through these pores. Here we show that transport occurs overwhelmingly after pulsing. First, we show that the electrical drift distance for typical charged solutes during nanosecond pulses (up to 100 ns), even those with very large magnitudes (up to 10 MV/m), ranges from only a fraction of the membrane thickness (5 nm) to several membrane thicknesses. This is much smaller than the diameter of a typical cell (∼16 μm), which implies that molecular drift transport during nanosecond pulses is necessarily minimal. This implication is not dependent on assumptions about pore density or the molecular flux through pores. Second, we show that molecular transport resulting from post-pulse diffusion through minimum-size pores is orders of magnitude larger than electrical drift-driven transport during nanosecond pulses. While field-assisted charge entry and the magnitude of flux favor transport during nanosecond pulses, these effects are too small to overcome the orders of magnitude more time available for post-pulse transport. Therefore, the basic conclusion that essentially all transmembrane molecular transport occurs post-pulse holds across the plausible range of relevant parameters. Our analysis shows that a primary direct consequence of nanosecond electric pulses is the creation (or maintenance) of large populations of small pores in cell membranes that govern post-pulse transmembrane transport of small ions and molecules. Copyright © 2011 Elsevier Inc. All rights reserved.

Acquisition of a Nanosecond Laser Flash Photolysis Spectrometer to Enhance Understanding of Photochemistry and Reaction Kinetics in Undergraduate Research/Curriculum

Science.gov (United States)

2016-03-31

photocathode, 16% peak QE typ., P43 phosphor , 7ns gate width, 500 kHz photocathode repetition rate, Intelligate, integrated 3x output ultra-low jitter digital...Application Note, Publication Number AN.014.S20. (4) Comerford, J. Monitoring fast reactions using Stopped Flow Kinetics on the Cary 50/60 UV - Vis, Agilent Application Note 2011, Publication Number SI-A-1177.

Flashing inception in flowing liquids

International Nuclear Information System (INIS)

Jones, O.C. Jr.

1979-01-01

The inception of net vaporization in flashing flows is examined. It is suggested that the flashing inception can be expressed as two additive effects. One is due to the static decompression which is a function of the spinodal limit and also of the expansion rate. The other effect which is a function of Reynolds number and flashing index, is due to the turbulent fluctuations of the flowing liquid. It is shown that by taking a three standard deviation band on the turbulent velocity fluctuations, an adequate representation of the inverse mass flux effect on flashing inception for existing data is obtained

Mass-dependent and non-mass-dependent isotope effects in ozone photolysis: Resolving theory and experiments

International Nuclear Information System (INIS)

Cole, Amanda S.; Boering, Kristie A.

2006-01-01

In addition to the anomalous 17 O and 18 O isotope effects in the three-body ozone formation reaction O+O 2 +M, isotope effects in the destruction of ozone by photolysis may also play a role in determining the isotopic composition of ozone and other trace gases in the atmosphere. While previous experiments on ozone photolysis at 254 nm were interpreted as evidence for preferential loss of light ozone that is anomalous (or 'non-mass-dependent'), recent semiempirical theoretical calculations predicted a preferential loss of heavy ozone at that wavelength that is mass dependent. Through photochemical modeling results presented here, we resolve this apparent contradiction between experiment and theory. Specifically, we show that the formation of ozone during the UV photolysis experiments is not negligible, as had been assumed, and that the well-known non-mass-dependent isotope effects in ozone formation can account for the non-mass-dependent enrichment of the heavy isotopologs of ozone observed in the experiment. Thus, no unusual non-mass-dependent fractionation in ozone photolysis must be invoked to explain the experimental results. Furthermore, we show that theoretical predictions of a mass-dependent preferential loss of the heavy isotopologs of ozone during UV photolysis are not inconsistent with the experimental data, particularly if mass-dependent isotope effects in the chemical loss reactions of ozone during the photolysis experiments or experimental artifacts enrich the remaining ozone in 17 O and 18 O. Before the calculated fractionation factors can be quantitatively evaluated, however, further investigation of possible mass-dependent isotope effects in the reactions of ozone with O( 1 D), O( 3 P), O 2 ( 1 Δ), and O 2 ( 1 Σ) is needed through experiments we suggest here

Menopausal Hot Flashes and White Matter Hyperintensities

Science.gov (United States)

Thurston, Rebecca C.; Aizenstein, Howard J.; Derby, Carol A.; Sejdić, Ervin; Maki, Pauline M.

2015-01-01

Objective Hot flashes are the classic menopausal symptom. Emerging data links hot flashes to cardiovascular disease (CVD) risk, yet how hot flashes are related to brain health is poorly understood. We examined the relationship between hot flashes - measured via physiologic monitor and self-report - and white matter hyperintensities (WMH) among midlife women. Methods Twenty midlife women ages 40-60 without clinical CVD, with their uterus and both ovaries, and not taking hormone therapy were recruited. Women underwent 24 hours of ambulatory physiologic and diary hot flash monitoring to quantify hot flashes; magnetic resonance imaging to assess WMH burden; 72 hours of actigraphy and questionnaires to quantify sleep; and a blood draw, questionnaires, and physical measures to quantify demographics and CVD risk factors. Test of a priori hypotheses regarding relations between physiologically-monitored and self-reported wake and sleep hot flashes and WMH were conducted in linear regression models. Results More physiologically-monitored hot flashes during sleep were associated with greater WMH, controlling for age, race, and body mass index [beta(standard error)=.0002 (.0001), p=.03]. Findings persisted controlling for sleep characteristics and additional CVD risk factors. No relations were observed for self-reported hot flashes. Conclusions More physiologically-monitored hot flashes during sleep were associated with greater WMH burden among midlife women free of clinical CVD. Results suggest that relations between hot flashes and CVD risk observed in the periphery may extend to the brain. Future work should consider the unique role of sleep hot flashes in brain health. PMID:26057822

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

Photolysis of oxyfluorfen in aqueous methanol.

Science.gov (United States)

Chakraborty, Subhasish K; Chakraborty, Savitri; Bhattacharyya, Anjan; Chowdhury, Ashim

2013-01-01

Photolysis of oxyfluorfen, an herbicide of the nitrodiphenyl ether class, was studied in aqueous methanol under UV and sunlight. UV irradiation was carried out in a borosilicate glass photoreactor (containing 250 ppm oxyfluorfen in 50% aqueous methanol) equipped with a quartz filter and 125 watt mercury lamp (maximum output 254 nm) at 25 ± 1°C. Sunlight irradiation was conducted at 28 ± 1°C in borosilicate Erlenmeyer flasks containing 250 ppm oxyfluorfen in 50% aqueous methanol. The samples from both the irradiated conditions were withdrawn at a definite time interval and extracted to measure oxyfluorfen content by gas chromatography-flame ionization detector for rate study. The half-life values were 20 hours and 2.7 days under UV and sunlight exposure, respectively. Photolysis of oxyfluorfen yielded 13 photoproducts of which three were characterized by infrared spectrophotometer and (1)H NMR and (13)C NMR spectroscopy. The rest of the photoproducts were identified by gas chromatography-mass spectrometry (GC-MS) and thin layer chromatography (TLC). An ionization potential 70 eV was used for electron impact-mass spectrometry (EI-MS) and methane was used as reagent gas for chemical ionization-mass spectrometry (CI-MS). Two of the photoproducts were also synthesized for comparison. The main phototransformation pathways of oxyfluorfen involved nitro reduction, dechlorination, and hydrolysis as well as nucleophiles displacement reaction.

Detection of Malicious Flash Banner Advertisements

Directory of Open Access Journals (Sweden)

Kirill Alekseevich Samosadnyy

2014-09-01

Full Text Available The paper addresses the problem of detecting malicious flash advertisements. As a result, detection method based on dynamic analysis that modify flash application and execute it in Adobe Flash player is proposed and evaluated on synthetic and real world examples.

Impacts of cloud water droplets on the OH production rate from peroxide photolysis.

Science.gov (United States)

Martins-Costa, M T C; Anglada, J M; Francisco, J S; Ruiz-López, Manuel F

2017-12-06

Understanding the difference between observed and modeled concentrations of HO x radicals in the troposphere is a current major issue in atmospheric chemistry. It is widely believed that existing atmospheric models miss a source of such radicals and several potential new sources have been proposed. In recent years, interest has increased on the role played by cloud droplets and organic aerosols. Computer modeling of ozone photolysis, for instance, has shown that atmospheric aqueous interfaces accelerate the associated OH production rate by as much as 3-4 orders of magnitude. Since methylhydroperoxide is a main source and sink of HO x radicals, especially at low NO x concentrations, it is fundamental to assess what is the influence of clouds on its chemistry and photochemistry. In this study, computer simulations for the photolysis of methylhydroperoxide at the air-water interface have been carried out showing that the OH production rate is severely enhanced, reaching a comparable level to ozone photolysis.

On multiphase negative flash for ideal solutions

DEFF Research Database (Denmark)

Yan, Wei; Stenby, Erling Halfdan

2012-01-01

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......There is a recent interest to solve multiphase negative flash problems where the phase amounts can be negative for normal positive feed composition. Solving such a negative flash problem using successive substitution needs an inner loop for phase distribution calculation at constant fugacity...... 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...

Measuring hot flash phenomenonology using ambulatory prospective digital diaries

Science.gov (United States)

Fisher, William I.; Thurston, Rebecca C.

2016-01-01

Objective This study provides the description, protocol, and results from a novel prospective ambulatory digital hot flash phenomenon diary. Methods This study included 152 midlife women with daily hot flashes who completed an ambulatory electronic hot flash diary continuously for the waking hours of 3 consecutive days. In this diary, women recorded their hot flashes and accompanying characteristics and associations as the hot flashes occurred. Results Self-reported hot flash severity on the digital diaries indicated that the majority of hot flashes were rated as mild (41.3%) or moderate (43.7%). Severe (13.1%) and very severe (1.8%) hot flashes were less common. Hot flash bother ratings were rated as mild (43%), or moderate (33.5%), with fewer hot flashes reported bothersome (17.5%) or very bothersome (6%). The majority of hot flashes were reported as occurring on the on the face (78.9%), neck (74.7%), and chest (61.3%). Prickly skin was reported concurrently with 32% of hot flashes, 7% with anxiety and 5% with nausea. A novel finding, 38% of hot flashes were accompanied by a premonitory aura. Conclusion A prospective electronic digital hot flash diary allows for a more precise quantitation of hot flashes while overcoming many of the limitations of commonly employed retrospective questionnaires and paper diaries. Unique insights into the phenomenology, loci and associated characteristics of hot flashes were obtained using this device. The digital hot flash phenomenology diary is recommended for future ambulatory studies of hot flashes as a prospective measure of the hot flash experience. PMID:27404030

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. N 2 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 N 2 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.

Chloride effect on the early photolysis intermediates of a gecko cone-type visual pigment.

Science.gov (United States)

Lewis, J W; Liang, J; Ebrey, T G; Sheves, M; Kliger, D S

1995-05-02

Nanosecond laser photolysis measurements were conducted on the cone-type visual pigment P521 in digitonin extracts of Tokay gecko (Gekko gekko) retina containing physiological chloride ion levels and also on samples which had been chloride depleted or which contained high levels (4 M) of chloride. Absorbance difference spectra were recorded at a sequence of time delays from 30 ns to 60 microseconds following excitation with a pulse of either 532- or 477-nm actinic light. Global analysis showed the kinetic decay data for gecko pigment P521 to be best fit by two exponential processes under all chloride conditions. The initial photoproduct detected had a broad spectrum characteristic of an equilibrated mixture of a Batho P521 intermediate with its blue-shifted intermediate (BSI P521) decay product. The first exponential process was assigned to the decay of this mixture to the Lumi P521 intermediate. The second exponential process was identified as the decay of Lumi P521 to Meta I P521. The initial photoproduct's spectrum exhibited a strong dependence on chloride concentration, indicating that chloride affects the composition of the equilibrated mixture of Batho P521 and BSI P521. These results suggest that the affinity for chloride is reduced approximately 5-fold in the Batho P521 intermediate and approximately 50-fold in the BSI P521 intermediate. Chloride concentration also affects the apparent decay rate of the equilibrated mixture. When the apparent decay rate is corrected for the composition of the equilibrated mixture, a relatively invariant microscopic rate constant is obtained for BSI decay (k = 1/55 ns-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Degradation of Paracetamol by Photolysis Using C-N-codoped TiO2

Directory of Open Access Journals (Sweden)

Vanny Yulia Safitri

2017-11-01

Full Text Available Paracetamol is generally used as analgesic and antipyretic drugs. Contamination paracetamol in the environment can occur because of waste material disposal from production site and immediate disposal of household that cause water pollution. Paracetamol is degraded by photolysis method under irradiation 10 watt UV-light (λ=365 nm, visible-light (Philips LED 13 watt 1400 lux and solar-light with and without addition C-N-codoped TiO2catalyst. The solution is analyzed by UV-Vis spectrophotometer at λ 200-400 nm. Optimum weight of C-N-codoped TiO2 catalyst obtained is 20 mg under UV-light photolysis. Paracetamol 4 mg/L is degraded 45.48% after 120 minutes under UV-light irradiation without catalyst, and increases to be 69.31% by using 20 mg catalyst. While degradation percentage of paracetamol is 16.96 % without catalyst, the percentage increases to be 34.29% after using 20 mg catalyst for 120 minutes photolysis under visible-light. Degradation of paracetamol by solar light achieves only 12.27% in absance of catalyst for 120 minutes irradiation, but it increases significantly until 70.39% in presence of 20 mg catalyst.

Flashing inception in flowing liquids

International Nuclear Information System (INIS)

Jones, O.C. Jr.

1980-01-01

The inception of net vaporization in flashing flows is examined. It is suggested that the flashing inception can be expressed as two additive effects. One is due to the static decompression which is a function of the initial temperature and also the expansion rate. The other effect which is a function of Reynolds number and flashing index, is due to the turbulent fluctuations of the flowing liquid. It is shown that by taking a three standard deviation band on the turbulent velocity fluctuations, an adequate representation of the inverse mass flux effect on flashing inception for existing data is obtained. The turbulence effects are combined with the correlation of Alamgir and Lienhard to provide predictive methods recommended for the case where both static and convective decompression effects exist

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...... thereby harming performance and device lifetime. In this paper, we identify a key component of the metadata called the Page Validity Bitmap (PVB) as the bottleneck. PVB is used by the garbage-collectors of state-of-the-art FTLs to keep track of which physical pages in the device are invalid. PVB...... constitutes 95% of the FTL's RAM-resident metadata, and recovering PVB after power fails takes a significant proportion of the overall recovery time. To solve this problem, we propose a page-associative FTL called GeckoFTL, whose central innovation is replacing PVB with a new data structure called Logarithmic...

Nanosecond fluorescence spectroscopy

International Nuclear Information System (INIS)

Leskovar, B.

1985-03-01

This article is a summary of a short course lecture given in conjunction with the 1984 Nuclear Science Symposium. Measuring systems for nanosecond fluorescence spectroscopy using single-photon counting techniques are presented. These involve systems based on relaxation-type spark gap light pulser and synchronously pumped mode-locked dye lasers. Furthermore, typical characteristics and optimization of operating conditions of the critical components responsible for the system time resolution are discussed. A short comparison of the most important deconvolution methods for numerical analysis of experimental data is given particularly with respect to the signal-to-noise ratio of the fluorescence signal. 22 refs., 8 figs

An Analysis of Total Lightning Flash Rates Over Florida

Science.gov (United States)

Mazzetti, Thomas O.; Fuelberg, Henry E.

2017-12-01

Although Florida is known as the "Sunshine State", it also contains the greatest lightning flash densities in the United States. Flash density has received considerable attention in the literature, but lightning flash rate has received much less attention. We use data from the Earth Networks Total Lightning Network (ENTLN) to produce a 5 year (2010-2014) set of statistics regarding total flash rates over Florida and adjacent regions. Instead of tracking individual storms, we superimpose a 0.2° × 0.2° grid over the study region and count both cloud-to-ground (CG) and in-cloud (IC) flashes over 5 min intervals. Results show that the distribution of total flash rates is highly skewed toward small values, whereas the greatest rate is 185 flashes min-1. Greatest average annual flash rates ( 3 flashes min-1) are located near Orlando. The southernmost peninsula, North Florida, and the Florida Panhandle exhibit smaller average annual flash rates ( 1.5 flashes min-1). Large flash rates > 100 flashes min-1 can occur during any season, at any time during the 24 h period, and at any location within the domain. However, they are most likely during the afternoon and early evening in East Central Florida during the spring and summer months.

A global flash flood forecasting system

Science.gov (United States)

Baugh, Calum; Pappenberger, Florian; Wetterhall, Fredrik; Hewson, Tim; Zsoter, Ervin

2016-04-01

The sudden and devastating nature of flash flood events means it is imperative to provide early warnings such as those derived from Numerical Weather Prediction (NWP) forecasts. Currently such systems exist on basin, national and continental scales in Europe, North America and Australia but rely on high resolution NWP forecasts or rainfall-radar nowcasting, neither of which have global coverage. To produce global flash flood forecasts this work investigates the possibility of using forecasts from a global NWP system. In particular we: (i) discuss how global NWP can be used for flash flood forecasting and discuss strengths and weaknesses; (ii) demonstrate how a robust evaluation can be performed given the rarity of the event; (iii) highlight the challenges and opportunities in communicating flash flood uncertainty to decision makers; and (iv) explore future developments which would significantly improve global flash flood forecasting. The proposed forecast system uses ensemble surface runoff forecasts from the ECMWF H-TESSEL land surface scheme. A flash flood index is generated using the ERIC (Enhanced Runoff Index based on Climatology) methodology [Raynaud et al., 2014]. This global methodology is applied to a series of flash floods across southern Europe. Results from the system are compared against warnings produced using the higher resolution COSMO-LEPS limited area model. The global system is evaluated by comparing forecasted warning locations against a flash flood database of media reports created in partnership with floodlist.com. To deal with the lack of objectivity in media reports we carefully assess the suitability of different skill scores and apply spatial uncertainty thresholds to the observations. To communicate the uncertainties of the flash flood system output we experiment with a dynamic region-growing algorithm. This automatically clusters regions of similar return period exceedence probabilities, thus presenting the at-risk areas at a spatial

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.

Amorphous Terfenol-D films using nanosecond pulsed laser deposition

International Nuclear Information System (INIS)

Ma, James; O'Brien, Daniel T.; Kovar, Desiderio

2009-01-01

Thin films of Terfenol-D were produced by nanosecond pulsed laser deposition (PLD) at two fluences. Electron dispersive spectroscopy conducted using scanning electron and transmission electron microscopes showed that the film compositions were similar to that of the PLD target. Contrary to previous assertions that suggested that nanosecond PLD results in crystalline films, X-ray diffraction and transmission electron microscopy analysis showed that the films produced at both fluences were amorphous. Splatters present on the film had similar compositions to the overall film and were also amorphous. Magnetic measurements showed that the films had high saturation magnetization and magnetostriction, similar to high quality films produced using other physical vapor deposition methods.

Formation of radical cations of diaryloxadiazoles

International Nuclear Information System (INIS)

Helmstreit, W.

1988-01-01

The nature of the formation of the radical cation of the 2,5-bis-(p-diethylaminophenyl)-1,3,4-oxadiazole (PC) in liquid n-butyl chloride and acetonitrile has been investigated by observing excited state fluorescence and transient absorption using nanosecond pulse radiolysis and laser flash photolysis. The formation of solute oxonium ions has also been observed. At concentrations -4 mol dm -3 the growth time at which the transient absorption of the radical cation reaches the maximum follows the rise time of the electron pulse ( 2 laser yields the solute radical cation in an acetonitrile solution of 2 x 10 -4 mol dm -3 PC via an electronically excited state. Here, the generation time was smaller than 5 ns. The yield of the cation is increased by addition of CCl 4 . A reaction mechanism is proposed that explains the fast cation formation in terms of an exciplex formed by interaction between an electronically excited state of diaryloxadiazole and the ground state of the solvent. This exciplex yields the solute radical cation. (author)

Unimolecular H2 elimination during the liquid phase radiolysis and photolysis of alkane - alkane mixtures

International Nuclear Information System (INIS)

Wojnarovits, L.; Foeldiak, G.

1980-01-01

Unimolecular H 2 elimination from alkanes was investigated in cyclopentane-cyclohexane, n-hexane-cyclohexane and cyclohexane-cyclooctane mixtures during fluradiolysis and 7.6 eV photolysis. During the radiolysis of all systems, and when the fluorescence shift law allowed it, during the photolysis as well, inhibited H 2 detachment was observed from the first component and sensitized hydrogen molecule elimination from the second. It has been concluded that the same excited state (the lowest singlet, S 1 ) is responsible for the H 2 elimination during radiolysis and photolysis and this is that one that gives rise to fluorescence in the experiments of other authors. The H 2 and H elimination from alkanes generally have different excited precursors. The direct population of S 1 by γ-irradiation is of limited importance and this intermediate is mainly produced in ''charge neutralization'' processes. (author)

Flashing coupled density wave oscillation

International Nuclear Information System (INIS)

Jiang Shengyao; Wu Xinxin; Zhang Youjie

1997-07-01

The experiment was performed on the test loop (HRTL-5), which simulates the geometry and system design of the 5 MW reactor. The phenomenon and mechanism of different kinds of two-phase flow instabilities, namely geyser instability, flashing instability and flashing coupled density wave instability are described. The especially interpreted flashing coupled density wave instability has never been studied well, it is analyzed by using a one-dimensional non-thermo equilibrium two-phase flow drift model computer code. Calculations are in good agreement with the experiment results. (5 refs.,5 figs., 1 tab.)

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

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

present the design and results from the current flash spectroscopic system at the R.I. A hybrid mode-locked, cavity dumped dye laser is used to seed a...date require a HE sum of at least three exponentials to achieve an acceptable fit. Lettuce chloroplasts exhibit decay times of 100 psec., 500-600 psec...other lettuce preparations. A PS1 preparation from the cyanobacterium Chlorogloea Fritschii, which has been thoroughly characterised previously [2

New Measurements of Methyl Ethyl Ketone (MEK) Photolysis Rates and Their Relevance to Global Oxidative Capacity

Science.gov (United States)

Brewer, J.; Ravishankara, A. R.; Mellouki, A.; Fischer, E. V.; Kukui, A.; Véronique, D.; Ait-helal, W.; Leglise, J.; Ren, Y.

2017-12-01

Methyl ethyl ketone (MEK) is one of the most abundant ketones in the atmosphere. MEK can be emitted directly into the atmosphere from both anthropogenic and natural sources, and it is also formed during the gas-phase oxidation of volatile organic compounds (VOCs). MEK is lost via reaction with OH, photolysis and deposition to the surface. Similar to the other atmospheric ketones, the photolysis of MEK may represent a source of HOx (OH + HO2) radicals in the upper troposphere. The degradation of MEK also leads to the atmospheric formation of acetaldehyde and formaldehyde. This work presents a new analysis of the temperature dependence of MEK photolysis cross-sections and a quantification of MEK photolysis rates under surface pressures using the CNRS HELIOS outdoor atmospheric chamber (Chambre de simulation atmosphérique à irradiation naturelle d'Orléans; http://www.era-orleans.org/ERA-TOOLS/helios-project.html). Additionally, we use the GEOS-Chem 3-D CTM (version 10-01, www.geos-chem.org) to investigate the impact of these newly measured rates and cross-sections on the global distribution and seasonality of MEK, as well as its importance to the tropospheric oxidative capacity.

A Durable Flash Memory Search Tree

OpenAIRE

Clay III, James; Wortman, Kevin

2012-01-01

We consider the task of optimizing the B-tree data structure, used extensively in operating systems and databases, for sustainable usage on multi-level flash memory. Empirical evidence shows that this new flash memory tree, or FM Tree, extends the operational lifespan of each block of flash memory by a factor of roughly 27 to 70 times, while still supporting logarithmic-time search tree operations.

Photolysis of the antidepressants amisulpride and desipramine in wastewaters: Identification of transformation products formed and their fate

International Nuclear Information System (INIS)

Gros, Meritxell; Williams, Mike; Llorca, Marta; Rodriguez-Mozaz, Sara; Barceló, Damià; Kookana, Rai S.

2015-01-01

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 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 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

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.

Room temperature FePt nanoparticles formation kinetics by laser solution photolysis

CSIR Research Space (South Africa)

Nkosi, S

2012-04-01

Full Text Available An experiment has been designed to measure the radiation emission during photolysis, as well as the production of either positive or negative metallic ions in liquid from of FePt nanoparticles....

Time-kill kinetic analysis of antimicrobial chemotherapy based on hydrogen peroxide photolysis against Streptococcus mutans biofilm.

Science.gov (United States)

Shirato, Midori; Nakamura, Keisuke; Kanno, Taro; Lingström, Peter; Niwano, Yoshimi; Örtengren, Ulf

2017-08-01

A recently developed antimicrobial technique utilizing hydroxyl radicals generated by hydrogen peroxide (H 2 O 2 ) photolysis represents a promising new therapy for preventing and treating dental caries. The present study compared the antimicrobial time-kill kinetics of H 2 O 2 photolysis, conventional antiseptics, and antimicrobial photodynamic therapy (aPDT) against biofilm-forming Streptococcus mutans (cariogenic bacteria) grown on hydroxyapatite disks. H 2 O 2 photolysis was performed by irradiating the biofilm immersed in 3% H 2 O 2 with 365-nm light-emitting diode (LED) light at an irradiance of 1000mW/cm 2 for up to 1.5min. Antiseptic treatments consisted of 0.2% chlorhexidine gluconate, 0.5% povidone-iodine, and 3% H 2 O 2 . The biofilm was immersed in each antiseptic for up to 4min. aPDT was performed by irradiating the biofilm immersed in 100μM methylene blue or toluidine blue O with 655-nm laser light at 1000mW/cm 2 for up to 4min. Based on the time-kill assay, the decimal reduction value (D-value) of each treatment was determined. With a D-value of 0.06min, H 2 O 2 photolysis exhibited the highest bactericidal effect against biofilm-forming S. mutans. In contrast, antiseptics and aPDT exerted a slower bactericidal effect, with D-values of 0.9-2.7min. In conclusion, the antimicrobial technique based on H 2 O 2 photolysis using 365-nm LED represents a strong adjunctive chemotherapy for dental caries treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

Photolysis of 2,4,6-trinitrotoluene in seawater and estuary water: Impact of pH, temperature, salinity, and dissolved organic matter

International Nuclear Information System (INIS)

Luning Prak, Dianne J.; Breuer, James E.T.; Rios, Evelyn A.; Jedlicka, Erin E.; O'Sullivan, Daniel W.

2017-01-01

The influence of salinity, pH, temperature, and dissolved organic matter on the photolysis rate of 2,4,6-trinitrotoluene (TNT) in marine, estuary, and laboratory-prepared waters was studied using a Suntest CPS +® solar simulator equipped with optical filters. TNT degradation rates were determined using HPLC analysis, and products were identified using LC/MS. Minimal or no TNT photolysis occurred under a 395-nm long pass filter, but under a 295-nm filter, first-order TNT degradation rate constants and apparent quantum yields increased with increasing salinity in both natural and artificial seawater. TNT rate constants increased slightly with increasing temperature (10 to 32 °C) but did not change significantly with pH (6.4 to 8.1). The addition of dissolved organic matter (up to 5 mg/L) to ultrapure water, artificial seawater, and natural seawater increased the TNT photolysis rate constant. Products formed by TNT photolysis in natural seawater were determined to be 2,4,6-trinitrobenzaldehyde, 1,3,5-trinitrobenzene, 2,4,6-trinitrobenzoic acid, and 2-amino-4,6-dinitrobenzoic acid. - Highlights: • 2,4,6-trinitrotoluene (TNT) was photolyzed in marine, estuary, & laboratory waters. • TNT photolysis rates increased with increasing salinity & dissolved organic matter. • Temperature and pH had minimal impact on TNT photolysis in marine waters. • In seawater, TNT photolysis produced 1,3,5-trinitrobenzene & trinitrobenzaldehyde. • Polar products were 2,4,6-trinobenzoic acid & 2-amino-4,6-dinitrobenzoic acid.

Research of coal flash hydropyrolysis

Energy Technology Data Exchange (ETDEWEB)

Zhu, Z.; Zhu, H.; Wu, Y.; Tang, L.; Cheng, L.; Xu, Z. [East China University of Science and Technology, Shanghai (China)

2001-02-01

Using x-ray photoelectron spectroscopy (XPS) analyses the organic sufur of seven different Chinese coals and their semi-cokes from flash hydropyrolysis were studied. The results showed that the organic sulfur in coal was alkyal sulfur and thiophene with the peak of XPS located in 163.1-163.5 eV and 164.1-164.5 eV. The relative thiophene content in coal increased with the coal rank. The type of organic sulfur in semi-coke in flash hydropyrolysis was generally thiophene species; its XPS peak also located in 164.1-164.5 eV, and was in accord with its corresponding coal. Total alkyl sulfur and some thiophene sulfur were removed during the flash hydropyrolysis process. The alkyl sulfur had very high activity in hydrogenation reaction. Flash hydropyrolysis was an important new clean-coal technique and had notable desulfurization effect. 13 refs., 2 figs., 4 tabs.

Synthesis of silver nanoparticles by radiolysis, photolysis and chemical reduction of AgNO3 in Hibiscus sabdariffa infusion (karkade)

International Nuclear Information System (INIS)

Cataldo, Franco; Ursini, Ornella; Angelini, Giancarlo

2016-01-01

Silver nanoparticles of different average diameters were synthesized by γ-radiolysis, UV-photolysis and chemical reduction of AgNO 3 solutions in Hibiscus sabdariffa infusion commonly known as 'karkade'. The UV-photolysis was performed either by using a conventional Hg low pressure lamp emitting at 254 nm and also by using a new compact UV-LED source emitting at 360 nm. The kinetics rate constant of silver nanoparticles synthesis produced by γ-radiolysis and UV photolysis were determined and the average diameter of the resulting nanoparticles was estimated. (author)

Solar photolysis of ozone to singlet D oxygen atoms, O(1D)

International Nuclear Information System (INIS)

Blackburn, T.E.

1984-01-01

Ground level solar photolysis rate coefficients (jO 3 ) were measured for the photolysis of ozone by sunlight, (O 3 + hnu( 2 + O( 1 D)). The O( 1 D) atoms produced react with nitrous oxide (N 2 O) carrier gas to form higher oxides of nitrogen (NOx). Computer model predictions show that these are mainly N 2 O 5 and NO 3 . Seventy five days of data were taken during the summer of 1983, at Ann Arbor, Michigan, and are presented in the appendix. Over 390 clear air jO 3 values are correlated with effective ozone column densities, and 500 nm aerosol optical depths. The solar direct beam component of ozone photolysis was measured for the different aerosol optical depths, over two entire days from sun-up to sun-down. Temperature dependence of jO 3 was measured from 10 0 C to 39 0 C with good agreement to models. Comparison of jO 3 versus global and ultraviolet radiation are made under various ozone column densities and aerosol optical depths. A jO 3 -photometer was built using an interference filter to pass only ozone photolyzing light. Improvements to instrumental parts are shown for balloon and aircraft flyable payloads

Photolysis of 5-bromouracil and some related compounds in solution. Pt. 6

International Nuclear Information System (INIS)

Campbell, J.M.; Sonntag, C. von; Schulte-Frohlinde, D.

1974-01-01

The steady state photolysis of 5-bromouracil (BU) in aqueous solution has been studied as a function of wavelength, pH, temperature, and hydrogen-donor concentration. Under all conditions studied, the primary reaction is shown to be C-Br bond cleavage followed by abstraction from the hydrogen-donor to give uracil and HBr. At pH > 12 further products are formed. In deoxygenated aqueous solution at pH 6, 20 0 C, and 254 nm, the quantum yield of BU consumption, PHI (-BU), is 1.8 x 10 -3 independent of hydrogen-donor type or concentration (e.g. 3 x 10 -2 to 2 m MeOH). With increasing pH, PHI (-BU) increases stepwise to 0.012 at pH 10 and to 0.28 at pH 14. pK-values calculated from these data are the same as ground state pK values. The results have been explained in terms of a homolytic dissociation of the C-Br bond of the excited BU followed by recombination or H atom abstraction by the radicals. At high hydrogen-donor concentration H atom abstraction can compete with cage recombination. A comparison has been made between BU photolysis in organic, hydrogen-donor solvents and BU photolysis within the DNA of bacteria or phages. (orig./HK) [de

Bipolar cloud-to-ground lightning flash observations

Science.gov (United States)

Saba, Marcelo M. F.; Schumann, Carina; Warner, Tom A.; Helsdon, John H.; Schulz, Wolfgang; Orville, Richard E.

2013-10-01

lightning is usually defined as a lightning flash where the current waveform exhibits a polarity reversal. There are very few reported cases of cloud-to-ground (CG) bipolar flashes using only one channel in the literature. Reports on this type of bipolar flashes are not common due to the fact that in order to confirm that currents of both polarities follow the same channel to the ground, one necessarily needs video records. This study presents five clear observations of single-channel bipolar CG flashes. High-speed video and electric field measurement observations are used and analyzed. Based on the video images obtained and based on previous observations of positive CG flashes with high-speed cameras, we suggest that positive leader branches which do not participate in the initial return stroke of a positive cloud-to-ground flash later generate recoil leaders whose negative ends, upon reaching the branch point, traverse the return stroke channel path to the ground resulting in a subsequent return stroke of opposite polarity.

Modelling and mitigation of Flash Crashes

OpenAIRE

Fry, John; Serbera, Jean-Philippe

2017-01-01

The algorithmic trading revolution has had a dramatic effect upon markets. Trading has become faster, and in some ways more efficient, though potentially at the cost higher volatility and increased uncertainty. Stories of predatory trading and flash crashes constitute a new financial reality. Worryingly, highly capitalised stocks may be particularly vulnerable to flash crashes. Amid fears of high-risk technology failures in the global financial system we develop a model for flash crashes....

Electro-optical muzzle flash detection

Science.gov (United States)

Krieg, Jürgen; Eisele, Christian; Seiffer, Dirk

2016-10-01

Localizing a shooter in a complex scenario is a difficult task. Acoustic sensors can be used to detect blast waves. Radar technology permits detection of the projectile. A third method is to detect the muzzle flash using electro-optical devices. Detection of muzzle flash events is possible with focal plane arrays, line and single element detectors. In this paper, we will show that the detection of a muzzle flash works well in the shortwave infrared spectral range. Important for the acceptance of an operational warning system in daily use is a very low false alarm rate. Using data from a detector with a high sampling rate the temporal signature of a potential muzzle flash event can be analyzed and the false alarm rate can be reduced. Another important issue is the realization of an omnidirectional view required on an operational level. It will be shown that a combination of single element detectors and simple optics in an appropriate configuration is a capable solution.

RELATIONSHIP BETWEEN FLASH POINTS OF SOME BINARY ...

African Journals Online (AJOL)

B. S. Chandravanshi

Miscellaneous binary blends containing solvent neutral-150 (SN-150), ... viscosity, the flash point test has always been a standard part of a lubricant's specification. ... between structure and flash points of organic compounds [5-12] and fuels [13, 14]. ... in binary mixtures, the gaps between flash points would be high enough.

A trial of ignition innovation of gasoline engine by nanosecond pulsed low temperature plasma ignition

International Nuclear Information System (INIS)

Shiraishi, Taisuke; Urushihara, Tomonori; Gundersen, Martin

2009-01-01

Application of nanosecond pulsed low temperature plasma as an ignition technique for automotive gasoline engines, which require a discharge under conditions of high back pressure, has been studied experimentally using a single-cylinder engine. The nanosecond pulsed plasma refers to the transient (non-equilibrated) phase of a plasma before the formation of an arc discharge; it was obtained by applying a high voltage with a nanosecond pulse (FWHM of approximately 80 or 25 ns) between coaxial cylindrical electrodes. It was confirmed that nanosecond pulsed plasma can form a volumetric multi-channel streamer discharge at an energy consumption of 60 mJ cycle -1 under a high back pressure of 1400 kPa. It was found that the initial combustion period was shortened compared with the conventional spark ignition. The initial flame visualization suggested that the nanosecond pulsed plasma ignition results in the formation of a spatially dispersed initial flame kernel at a position of high electric field strength around the central electrode. It was observed that the electric field strength in the air gap between the coaxial cylindrical electrodes was increased further by applying a shorter pulse. It was also clarified that the shorter pulse improved ignitability even further.

A trial of ignition innovation of gasoline engine by nanosecond pulsed low temperature plasma ignition

Science.gov (United States)

Shiraishi, Taisuke; Urushihara, Tomonori; Gundersen, Martin

2009-07-01

Application of nanosecond pulsed low temperature plasma as an ignition technique for automotive gasoline engines, which require a discharge under conditions of high back pressure, has been studied experimentally using a single-cylinder engine. The nanosecond pulsed plasma refers to the transient (non-equilibrated) phase of a plasma before the formation of an arc discharge; it was obtained by applying a high voltage with a nanosecond pulse (FWHM of approximately 80 or 25 ns) between coaxial cylindrical electrodes. It was confirmed that nanosecond pulsed plasma can form a volumetric multi-channel streamer discharge at an energy consumption of 60 mJ cycle-1 under a high back pressure of 1400 kPa. It was found that the initial combustion period was shortened compared with the conventional spark ignition. The initial flame visualization suggested that the nanosecond pulsed plasma ignition results in the formation of a spatially dispersed initial flame kernel at a position of high electric field strength around the central electrode. It was observed that the electric field strength in the air gap between the coaxial cylindrical electrodes was increased further by applying a shorter pulse. It was also clarified that the shorter pulse improved ignitability even further.

Method of the nanosecond microstructure creation of the negative ion beam

International Nuclear Information System (INIS)

Novikov-Borodin, A.V.

2001-01-01

The method of the nanosecond microstructure creation of the negative ion beam with nanosecond edge times is presented. The method of creation does not destroy the beam compensation by the residual gas,so it available for low-energy beams. Such effects as a beam divergence and,therefore,a bad beam transport are overcome. The two plate travelling wave chopper is used.The special shape of the plate deflecting voltage is needed. The estimations and a comparison with the existing methods of a beam deflection are presented

LOFAR Lightning Imaging: Mapping Lightning With Nanosecond Precision

Science.gov (United States)

Hare, B. M.; Scholten, O.; Bonardi, A.; Buitink, S.; Corstanje, A.; Ebert, U.; Falcke, H.; Hörandel, J. R.; Leijnse, H.; Mitra, P.; Mulrey, K.; Nelles, A.; Rachen, J. P.; Rossetto, L.; Rutjes, C.; Schellart, P.; Thoudam, S.; Trinh, T. N. G.; ter Veen, S.; Winchen, T.

2018-03-01

Lightning mapping technology has proven instrumental in understanding lightning. In this work we present a pipeline that can use lightning observed by the LOw-Frequency ARray (LOFAR) radio telescope to construct a 3-D map of the flash. We show that LOFAR has unparalleled precision, on the order of meters, even for lightning flashes that are over 20 km outside the area enclosed by LOFAR antennas (˜3,200 km2), and can potentially locate over 10,000 sources per lightning flash. We also show that LOFAR is the first lightning mapping system that is sensitive to the spatial structure of the electrical current during individual lightning leader steps.

The role of nanosecond electric pulse-induced mechanical stress in cellular nanoporation

Science.gov (United States)

Roth, Caleb C.

Background: Exposures of cells to very short (less than 1 microsecond) electric pulses in the megavolt/meter range have been shown to cause a multitude of effects, both physical and molecular in nature. Physically, nanosecond electrical pulse exposure can disrupt the plasma membrane, leading to a phenomenon known as nanoporation. Nanoporation is the production of nanometer sized holes (less than 2 nanometers in diameter) that can persist for up to fifteen minutes, allowing the flow of ions into and out of the cell. Nanoporation can lead to secondary physical effects, such as cellular swelling, shrinking and blebbing. Molecularly, nanosecond electrical pulses have been shown to activate signaling pathways, produce oxidative stress, stimulate hormone secretion and induce both apoptotic and necrotic death. The mechanism by which nanosecond electrical pulses cause molecular changes is unknown; however, it is thought the flow of ions, such as calcium, into the cell via nanopores, could be a major cause. The ability of nanosecond electrical pulses to cause membranes to become permeable and to induce apoptosis makes the technology a desirable modality for cancer research; however, the lack of understanding regarding the mechanisms by which nanosecond electrical pulses cause nanoporation impedes further development of this technology. This dissertation documents the genomic and proteomic responses of cells exposed to nanosecond electrical pulses and describes in detail the biophysical effects of these electrical pulses, including the demonstration for the first time of the generation of acoustic pressure transients capable of disrupting plasma membranes and possibly contributing to nanoporation. Methods: Jurkat, clone E6-1 (human lymphocytic cell line), U937 (human lymphocytic cell line), Chinese hamster ovarian cells and adult primary human dermal fibroblasts exposed to nanosecond electrical pulses were subjected to a variety of molecular assays, including flow cytometry

Flash x-ray

International Nuclear Information System (INIS)

Johnson, Q.; Pellinen, D.

1976-01-01

The complementary techniques of flash x-ray radiography (FXR) and flash x-ray diffraction (FXD) provide access to a unique domain in nondestructive materials testing. FXR is useful in studies of macroscopic properties during extremely short time intervals, and FXD, the newer technique, is used in studies of microscopic properties. Although these techniques are similar in many respects, there are some substantial differences. FXD generally requires low-voltage, line-radiation sources and extremely accurate timing; FXR is usually less demanding. Phenomena which can be profitably studied by FXR often can also be studied by FXD to permit a complete materials characterization

Absolute absorption cross-section and photolysis rate of I2

Directory of Open Access Journals (Sweden)

A. Saiz-Lopez

2004-01-01

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 (295K, 760Torr was therefore measured between 182 and 750nm using a Fourier Transform spectrometer at a resolution of 4cm-1 (0.1nm at λ=500nm. The maximum absorption cross-section in the visible region was observed at λ=533.0nm to be σ=(4.24±0.50x10-18cm2molecule-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±0.03s-1 for the lower troposphere. This is in excellent agreement with the value of 0.12±0.015s-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.

Photodegradation of dimethyl sulfide (DMS) in natural waters: laboratory assessment of the nitrate-photolysis-induced DMS oxidation.

Science.gov (United States)

Bouillon, René-Christian; Miller, William L

2005-12-15

The interaction of sunlight and dissolved chromophoric matter produces reactive chemical species that are significant in the removal of dimethyl sulfide (DMS) in the surface ocean. Using artificial solar radiation, we examined the role of several inorganic components of seawater on the kinetics of NO3- -photolysis-induced DMS removal in aqueous solution. This study strongly suggests that NO3- photolysis products react significantly with DMS in aqueous solution possibly via an electrophilic attack on the electron-rich sulfur atom. This supports previous field observations that indicate that NO3- photolysis has a substantial control on DMS photochemistry in nutrient-rich waters. A key finding of this research is that the oxidation rate of DMS induced by NO3- photolysis is dramatically enhanced in the presence of bromide ion. Moreover, our results suggest that bicarbonate/carbonate ions are involved in free radical production/scavenging processes important for DMS photochemistry. These reactions are pH dependent. We propose that DMS removal by some selective free radicals derived from bromide and bicarbonate/carbonate ion oxidation is a potentially important and previously unrecognized pathway for DMS photodegradation in marine waters.

Elucidating Direct Photolysis Mechanisms of Different Dissociation Species of Norfloxacin in Water and Mg2+ Effects by Quantum Chemical Calculations.

Science.gov (United States)

Wang, Se; Wang, Zhuang

2017-11-11

The study of pollution due to combined antibiotics and metals is urgently needed. Photochemical processes are an important transformation pathway for antibiotics in the environment. The mechanisms underlying the effects of metal-ion complexation on the aquatic photochemical transformation of antibiotics in different dissociation forms are crucial problems in science, and beg solutions. Herein, we investigated the mechanisms of direct photolysis of norfloxacin (NOR) in different dissociation forms in water and metal ion Mg 2+ effects using quantum chemical calculations. Results show that different dissociation forms of NOR had different maximum electronic absorbance wavelengths (NOR 2+ direct photolysis pathways were de-ethylation (N7-C8 bond cleavage) and decarboxylation (C2-C5 bond cleavage). Furthermore, the presence of Mg 2+ changed the order of the wavelength at maximum electronic absorbance (NOR⁺-Mg 2+ direct photolysis of NOR⁰, NOR⁺, and NOR 2+ . The calculated TS results indicated that the presence of Mg 2+ increased E a for most direct photolysis pathways of NOR, while it decreased E a for some direct photolysis pathways such as the loss of the piperazine ring and the damage of the piperazine ring of NOR⁰ and the defluorination of NOR⁺.

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

Characteristics of 2-heptanone decomposition using nanosecond pulsed discharge plasma

Science.gov (United States)

Nakase, Yuki; Fukuchi, Yuichi; Wang, Douyan; Namihira, Takao; Akiyama, Hidenori; Kumamoto University Collaboration

2015-09-01

Volatile organic compounds (VOC) evaporate at room temperature. VOCs typically consist of toluene, benzene and ethyl acetate, which are used in cosmetics, dry cleaning products and paints. Exposure to elevated levels of VOCs may cause headaches, dizziness and irritation to the eyes, nose, and throat; they may also cause environmental problems such as air pollution, acid rain and photochemical smog. As such, they require prompt removal. Nanosecond pulsed discharge is a kind of non-thermal plasma consisting of a streamer discharge. Several advantages of nanosecond pulsed discharge plasma have been demonstrated by studies of our research group, including low heat loss, highly energetic electron generation, and the production of highly active radicals. These advantages have shown ns pulsed discharge plasma capable of higher energy efficiency for processes, such as air purification, wastewater treatment and ozone generation. In this research, nanosecond pulsed discharge plasma was employed to treat 2-heptanone, which is a volatile organic compound type and presents several harmful effects. Characteristics of treatment dependent on applied voltage, gas flow rate and input energy density were investigated. Furthermore, byproducts generated by treatment were also investigated.

Hot Flashes amd Night Sweats (PDQ)

Science.gov (United States)

... Professionals Questions to Ask about Your Treatment Research Hot Flashes and Night Sweats (PDQ®)–Patient Version Overview ... quality of life in many patients with cancer. Hot flashes and night sweats may be side effects ...

"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. © 2015 Society for Risk Analysis.

Nanosecond bipolar pulse generators for bioelectrics.

Science.gov (United States)

Xiao, Shu; Zhou, Chunrong; Yang, Enbo; Rajulapati, Sambasiva R

2018-04-26

Biological effects caused by a nanosecond pulse, such as cell membrane permeabilization, peripheral nerve excitation and cell blebbing, can be reduced or cancelled by applying another pulse of reversed polarity. Depending on the degree of cancellation, the pulse interval of these two pulses can be as long as dozens of microseconds. The cancellation effect diminishes as the pulse duration increases. To study the cancellation effect and potentially utilize it in electrotherapy, nanosecond bipolar pulse generators must be made available. An overview of the generators is given in this paper. A pulse forming line (PFL) that is matched at one end and shorted at the other end allows a bipolar pulse to be produced, but no delay can be inserted between the phases. Another generator employs a combination of a resistor, an inductor and a capacitor to form an RLC resonant circuit so that a bipolar pulse with a decaying magnitude can be generated. A third generator is a converter, which converts an existing unipolar pulse to a bipolar pulse. This is done by inserting an inductor in a transmission line. The first phase of the bipolar pulse is provided by the unipolar pulse's rising phase. The second phase is formed during the fall time of the unipolar pulse, when the inductor, which was previously charged during the flat part of the unipolar pulse, discharges its current to the load. The fourth type of generator uses multiple MOSFET switches stacked to turn on a pre-charged, bipolar RC network. This approach is the most flexible in that it can generate multiphasic pulses that have different amplitudes, delays, and durations. However, it may not be suitable for producing short nanosecond pulses (<100 ns), whereas the PFL approach and the RLC approach with gas switches are used for this range. Thus, each generator has its own advantages and applicable range. Copyright © 2018 Elsevier B.V. All rights reserved.

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.

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...need to be addressed, the Flash Bainite processing of 4130 steel demonstrates promise for applications needing a combination of high strength with

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.

Physiologically assessed hot flashes and endothelial function among midlife women.

Science.gov (United States)

Thurston, Rebecca C; Chang, Yuefang; Barinas-Mitchell, Emma; Jennings, J Richard; von Känel, Roland; Landsittel, Doug P; Matthews, Karen A

2017-08-01

Hot flashes are experienced by most midlife women. Emerging data indicate that they may be associated with endothelial dysfunction. No studies have tested whether hot flashes are associated with endothelial function using physiologic measures of hot flashes. We tested whether physiologically assessed hot flashes were associated with poorer endothelial function. We also considered whether age modified associations. Two hundred seventy-two nonsmoking women reporting either daily hot flashes or no hot flashes, aged 40 to 60 years, and free of clinical cardiovascular disease, underwent ambulatory physiologic hot flash and diary hot flash monitoring; a blood draw; and ultrasound measurement of brachial artery flow-mediated dilation to assess endothelial function. Associations between hot flashes and flow-mediated dilation were tested in linear regression models controlling for lumen diameter, demographics, cardiovascular disease risk factors, and estradiol. In multivariable models incorporating cardiovascular disease risk factors, significant interactions by age (P hot flashes (beta [standard error] = -2.07 [0.79], P = 0.01), and more frequent physiologic hot flashes (for each hot flash: beta [standard error] = -0.10 [0.05], P = 0.03, multivariable) were associated with lower flow-mediated dilation. Associations were not accounted for by estradiol. Associations were not observed among the older women (age 54-60 years) or for self-reported hot flash frequency, severity, or bother. Among the younger women, hot flashes explained more variance in flow-mediated dilation than standard cardiovascular disease risk factors or estradiol. Among younger midlife women, frequent hot flashes were associated with poorer endothelial function and may provide information about women's vascular status beyond cardiovascular disease risk factors and estradiol.

Principles of arc flash protection

Energy Technology Data Exchange (ETDEWEB)

Hirschmann, R. B.

2003-04-01

Recent developments in NFPA 70E, the electrical safety standards in the United States and Canada, designed to provide for a safe industrial work environment, are discussed. The emphasis in this instance is on arc explosions. Development of an arc flash protective program is discussed under various major components of an electrical safety program. These are: appropriate qualifications and training for workers, safe work practices, appropriate hazard assessment practices for any task exceeding 50V where there is the potential of an arc flash accident, flash protection equipment commensurate with the hazard associated with the task to be performed, layering in protective clothing over all body surfaces, and strict adherence to rules regarding use of safety garments and equipment.

Formation of various types of nanostructures on germanium surface by nanosecond laser pulses

Science.gov (United States)

Mikolutskiy, S. I.; Khasaya, R. R.; Khomich, Yu V.; Yamshchikov, V. A.

2018-03-01

The paper describes the formation of micro- and nanostructures in different parts of irradiation zone on germanium surface by multiple action of nanosecond pulses of ArF-laser. It proposes a simple method using only one laser beam without any optional devices and masks for surface treatment. Hexa- and pentagonal cells with submicron dimensions along the surface were observed in peripheral zone of irradiation spot by atomic-force microscopy. Nanostructures in the form of bulbs with rounded peaks with lateral sizes of 40-120 nm were obtained in peripheral low-intensity region of the laser spot. Considering experimental data on material processing by nanosecond laser pulses, a classification of five main types of surface reliefs formed by nanosecond laser pulses with energy density near or slightly above ablation threshold was proposed.

Flash flood forecasting, warning and risk management: the HYDRATE project

International Nuclear Information System (INIS)

Borga, M.; Anagnostou, E.N.; Bloeschl, G.; Creutin, J.-D.

2011-01-01

Highlights: → We characterize flash flood events in various regions of Europe. → We provide guidance to improve observations and monitoring of flash floods. → Flash floods are associated to orography and are influenced by initial soil moisture conditions. → Models for flash flood forecasting and flash flood hazard assessment are illustrated and discussed. → We examine implications for flood risk policy and discuss recommendations received from end users. - Abstract: The management of flash flood hazards and risks is a critical component of public safety and quality of life. Flash-floods develop at space and time scales that conventional observation systems are not able to monitor for rainfall and river discharge. Consequently, the atmospheric and hydrological generating mechanisms of flash-floods are poorly understood, leading to highly uncertain forecasts of these events. The objective of the HYDRATE project has been to improve the scientific basis of flash flood forecasting by advancing and harmonising a European-wide innovative flash flood observation strategy and developing a coherent set of technologies and tools for effective early warning systems. To this end, the project included actions on the organization of the existing flash flood data patrimony across Europe. The final aim of HYDRATE was to enhance the capability of flash flood forecasting in ungauged basins by exploiting the extended availability of flash flood data and the improved process understanding. This paper provides a review of the work conducted in HYDRATE with a special emphasis on how this body of research can contribute to guide the policy-life cycle concerning flash flood risk management.

Carbenes and Nitrenes: Recent Developments in Fundamental Chemistry.

Science.gov (United States)

Wentrup, Curt

2018-05-29

There has been significant progress in the direct observation of carbenes, nitrenes, and many other reactive intermediates in recent years due to the application of matrix photolysis and flash vacuum pyrolysis linked with matrix isolation at cryogenic temperatures. Our understanding of singlet and triplet states has improved through the interplay of spectroscopy and computations. Bistable carbenes and nitrenes as well as many examples of tunneling have been discovered. Numerous rearrangements and fragmentations have been documented. This minireview aims to give an overview of some of these developments but will not generally cover laser flash photolysis and chemical reactions in liquid solution. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Geographical distribution of hot flash frequencies: considering climatic influences.

Science.gov (United States)

Sievert, Lynnette Leidy; Flanagan, Erin K

2005-10-01

Laboratory studies suggest that hot flashes are triggered by small elevations in core body temperature acting within a reduced thermoneutral zone, i.e., the temperature range in which a woman neither shivers nor sweats. In the present study, it was hypothesized that women in different populations develop climate-specific thermoneutral zones, and ultimately, population-specific frequencies of hot flashes at menopause. Correlations were predicted between hot flash frequencies and latitude, elevation, and annual temperatures. Data on hot flash frequencies were drawn from 54 studies. Pearson correlation analyses and simple linear regressions were applied, first using all studies, and second using a subset of studies that included participants only to age 60 (n = 36). Regressions were repeated with all studies, controlling for method of hot flash assessment. When analyses were restricted to studies that included women up to age 60, average temperature of the coldest month was a significant predictor of hot flash frequency (P hottest and coldest temperatures was also a significant predictor (P coldest month, difference between hottest and coldest temperatures, and mean annual temperature were significant predictors of hot flash frequency. Women reported fewer hot flashes in warmer temperatures, and more hot flashes with increasing seasonality. These results suggest that acclimatization to coldest temperatures or sensitivity to seasonality may explain part of the population variation in hot flash frequency.

Organic flash cycles for efficient power production

Science.gov (United States)

Ho, Tony; Mao, Samuel S.; Greif, Ralph

2016-03-15

This disclosure provides systems, methods, and apparatus related to an Organic Flash Cycle (OFC). In one aspect, a modified OFC system includes a pump, a heat exchanger, a flash evaporator, a high pressure turbine, a throttling valve, a mixer, a low pressure turbine, and a condenser. The heat exchanger is coupled to an outlet of the pump. The flash evaporator is coupled to an outlet of the heat exchanger. The high pressure turbine is coupled to a vapor outlet of the flash evaporator. The throttling valve is coupled to a liquid outlet of the flash evaporator. The mixer is coupled to an outlet of the throttling valve and to an outlet of the high pressure turbine. The low pressure turbine is coupled to an outlet of the mixer. The condenser is coupled to an outlet of the low pressure turbine and to an inlet of the pump.

Construction and performance of large flash chambers

International Nuclear Information System (INIS)

Taylor, F.E.; Bogert, D.; Fisk, R.; Stutte, L.; Walker, J.K.; Wolfson, J.; Abolins, M.; Ernwein, J.; Owen, D.; Lyons, T.

1979-01-01

The construction and performance of 12' x 12' flash chambers used in a 340 ton neutrino detector under construction at Fermilab is described. The flash chambers supply digital information with a spatial resolution of 0.2'', and are used to finely sample the shower development of the reaction products of neutrino interactions. The flash chambers are easy and inexpensive to build and are electronically read out

Non Volatile Flash Memory Radiation Tests

Science.gov (United States)

Irom, Farokh; Nguyen, Duc N.; Allen, Greg

2012-01-01

Commercial flash memory industry has experienced a fast growth in the recent years, because of their wide spread usage in cell phones, mp3 players and digital cameras. On the other hand, there has been increased interest in the use of high density commercial nonvolatile flash memories in space because of ever increasing data requirements and strict power requirements. Because of flash memories complex structure; they cannot be treated as just simple memories in regards to testing and analysis. It becomes quite challenging to determine how they will respond in radiation environments.

Microstructured silicon created with a nanosecond neodymium-doped yttrium aluminum garnet laser

Energy Technology Data Exchange (ETDEWEB)

Mandeville, W.J. [MITRE Corporation, Colorado Springs, CO (United States); Shaffer, M.K.; Lu, Yalin; O' Keefe, D.; Knize, R.J. [United States Air Force Academy, USAFA, CO (United States)

2011-08-15

We produce microstructured silicon using frequency doubled, nanosecond Nd:YAG pulses in SF{sub 6} gas. The micro-penitentes formed are up to 20 {mu}m tall with a sulfur concentration of 0.5% near the surface. The infrared absorption is increased to near unity and extends well below the original bandgap far into the infrared. These data are similar to results reported by others using more complicated and less economical femtosecond titanium sapphire and picosecond and nanosecond excimer lasers. (orig.)

Production of bio-oils from wood by flash pyrolysis; Herstellung von Bio-Oelen aus Holz in einer Flash-Pyrolyseanlage

Energy Technology Data Exchange (ETDEWEB)

Meier, D; Ollesch, T [Bundesforschungsanstalt fuer Forst- und Holzwirtschaft, Hamburg (Germany). Inst. fuer Holzchemie und Chemische Technologie des Holzes; Gerdes, C; Kaminsky, W [Hamburg Univ. (Germany). Inst. fuer Technische und Makromolekulare Chemie (ITMCh)

1998-09-01

Flash pyrolysis is a medium-temperature process (around 475 C) in which biomass is heated up rapidly in the absence of oxygen. The pyrolysis products are cooled down rapidly, condensing into a reddish-brown liquid with around half the calorific value of a conventional heating oil. In contrast to conventional charcoal production, flash pyrolysis is a modern process whose process parameters enure high liquid yields. Modern fluidized-bed reactors for flash pyrolysis of biomass tend to have high heating rates and short times of residue. In the `Hamburg process`, fluidized-bed reactors are used successfully for pyrolysis of plastics. A flash pyrolysis plant for biomass treatment was constructed in cooperation with Hamburg University with funds provided by the `Bundesstiftung Umwelt`. This contribution describes the first series of experiments, mass balances and oil analyses using beech wood as material to be pyrolyzed. (orig./SR) [Deutsch] Flash-Pyrolyse ist ein Mitteltemperatur-Prozess (ca. 475 C), in dem Biomasse unter Sauerstoffausschluss sehr schnell erhitzt wird. Die entstehenden Pyrolyseprodukte werden schnell abgekuehlt und kondensieren zu einer roetlich-braunen Fluessigkeit, die etwa die Haelfte des Heizwertes eines konventionellen Heizoeles besitzt. Flash-Pyrolyse ist, im Gegensatz zur konventionellen Holzverkohlung, ein modernes Verfahren, dessen spezielle Verfahrensparameter hohe Fluessigausbeuten ermoeglichen. Hohe Aufheizraten, verbunden mit kurzen Verweilzeiten, werden mit stationaeren Wirbelbettreaktoren erzielt die gegenwaertig vorwiegend fuer die Flash-Pyrolyse von Biomasse eingesetzt werden. Im `Hamburger Verfahren` haben sich Wirbelbettreaktoren im Bereich der Kunststoffpyrolyse bewaehrt. Daher wurde in Zusammenarbeit mit der Universitaet Hamburg und finanzieller Foerderung der Bundesstiftung Umwelt eine Flash-Pyrolyseanlage fuer Biomasse gebaut: In dieser Arbeit werden erste Versuchsreihen, Massenbilanzen und Oelanalysen aus der Pyrolyse von

Theory of optical flashes

International Nuclear Information System (INIS)

London, R.A.

1983-01-01

The theory of optical flashes created by x- and γ-ray burst heating of stars in binaries is reviewed. Calculations of spectra due to steady-state x-ray reprocessing and estimates of the fundamental time scales for the non-steady case are discussed. The results are applied to the extant optical data from x-ray and γ-ray bursters. Finally, I review predictions of flashes from γ-ray bursters detectable by a state of the art all-sky optical monitor

The Evolution and Structure of Extreme Optical Lightning Flashes.

Science.gov (United States)

Peterson, Michael; Rudlosky, Scott; Deierling, Wiebke

2017-12-27

This study documents the composition, morphology, and motion of extreme optical lightning flashes observed by the Lightning Imaging Sensor (LIS). The furthest separation of LIS events (groups) in any flash is 135 km (89 km), the flash with the largest footprint had an illuminated area of 10,604 km 2 , and the most dendritic flash has 234 visible branches. The longest-duration convective LIS flash lasted 28 s and is overgrouped and not physical. The longest-duration convective-to-stratiform propagating flash lasted 7.4 s, while the longest-duration entirely stratiform flash lasted 4.3 s. The longest series of nearly consecutive groups in time lasted 242 ms. The most radiant recorded LIS group (i.e., "superbolt") is 735 times more radiant than the average group. Factors that impact these optical measures of flash morphology and evolution are discussed. While it is apparent that LIS can record the horizontal development of the lightning channel in some cases, radiative transfer within the cloud limits the flash extent and level of detail measured from orbit. These analyses nonetheless suggest that lightning imagers such as LIS and Geostationary Lightning Mapper can complement ground-based lightning locating systems for studying physical lightning phenomena across large geospatial domains.

Timing in a FLASH

Science.gov (United States)

Hoek, M.; Cardinali, M.; Corell, O.; Dickescheid, M.; Ferretti B., M. I.; Lauth, W.; Schlimme, B. S.; Sfienti, C.; Thiel, M.

2017-12-01

A prototype detector, called FLASH (Fast Light Acquiring Start Hodoscope), was built to provide precise Time-of-Flight (TOF) measurements and reference timestamps for detector setups at external beam lines. Radiator bars, made of synthetic fused silica, were coupled to a fast MCP-PMT with 64 channels and read out with custom electronics using Time-over-Threshold (TOT) for signal characterization. The TRB3 system, a high-precision TDC implemented in an FPGA, was used as data acquisition system. The performance of a system consisting of two FLASH units was investigated at a dedicated test experiment at the Mainz Microtron (MAMI) accelerator using its 855 MeV electron beam. The TOT measurement enabled time walk corrections and an overall TOF resolution of ∼70 ps could be achieved which translates into a resolution of ∼50 ps per FLASH unit. The intrinsic resolution of the frontend electronics including the TDC was measured to be less than 25 ps.

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

) with zero binary-interaction parameters (BIPs) and later generalized to situations with nonzero-BIP matrices. 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 (2011) questioned...... 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...... directly using the sparsity of the BIP matrix....

A Moessbauer study on the photolysis of potassium trisoxalatoferrate(III) in solid and solutions

International Nuclear Information System (INIS)

Sato, H.; Tominaga, T.

1977-01-01

The photolysis of potassium trisoxalatoferrate(III) in solid and aqueous solutions was studied by Moessbauer spectroscopy. A ferrous species was mainly detected as an intermediate product in the photoirradiated solutions. A tentative mechanism was proposed for the overall reactions in and after the photolysis of this compound. The Moessbauer spectra were measured with a Hitachi AA-40 or Shimadzu MEG-2 Moessbauer spectrometer against Co-57 in copper foil. Acrylic holders (32 mm in diameter) were used for measurements of solutions: the irradiated solution was quickly frozen before measurement by adding it dropwise into the acrylic holder which had been cooled with liquid nitrogen or dry-ice. (T.I.)

An unusual characteristic "flower-like" pattern: flash suppressor burns.

Science.gov (United States)

Gurcan, Altun

2012-04-01

The case on contact shots from firearms with a flash suppressor is rare. When a rifle fitted with a flash suppressor is fired, the emerging soot-laden gas in the barrel escapes from the slits of the flash suppressor. If the shot is contact or near contact, the flash suppressor will produce a characteristic "flower-like" pattern of seared, blackened zones around the entrance. This paper presents the injury pattern of the flash suppressor in a 29-year-old man who committed suicide with a G3 automatic infantry rifle.

Flash memory in embedded Java programs

DEFF Research Database (Denmark)

Korsholm, Stephan Erbs

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...

Critical flashing flows in nozzles with subcooled inlet conditions

International Nuclear Information System (INIS)

Abuaf, N.; Jones, O.C. Jr.; Wu, B.J.C.

1983-01-01

Examination of a large number of experiments dealing with flashing flows in converging and converging-diverging nozzles reveals that knowledge of the flashing inception point is the key to the prediction of critical flow rates. An extension of the static flashing inception correlation of Jones [16] and Alamgir and Lienhard [17] to flowing systems has allowed the determination of the location of flashing inception in nozzle flows with subcooled inlet conditions. It is shown that in all the experiments examined with subcooled inlet regardless of the degree of inlet subcooling, flashing inception invariably occurred very close to the throat. A correlation is given to predict flashing inception in both pipes and nozzles which matches all data available, but is lacking verification in intermediate nozzle geometries where turbulence may be important. A consequence of this behavior is that the critical mass flux may be correlated to the pressure difference between the nozzle inlet and flashing inception, through a single phase liquid discharge coefficient and an accurate prediction of the flashing inception pressure at the throat. Comparison with the available experiments indicate that the predicted mass fluxes are within 5 percent of the measurements

Ozone and dinitrogen monoxide production in atmospheric pressure air dielectric barrier discharge plasma effluent generated by nanosecond pulse superimposed alternating current voltage

Science.gov (United States)

Takashima, Keisuke; Kaneko, Toshiro

2017-06-01

The effects of nanosecond pulse superposition to alternating current voltage (NS + AC) on the generation of an air dielectric barrier discharge (DBD) plasma and reactive species are experimentally studied, along with measurements of ozone (O3) and dinitrogen monoxide (N2O) in the exhausted gas through the air DBD plasma (air plasma effluent). The charge-voltage cycle measurement indicates that the role of nanosecond pulse superposition is to induce electrical charge transport and excess charge accumulation on the dielectric surface following the nanosecond pulses. The densities of O3 and N2O in NS + AC DBD are found to be significantly increased in the plasma effluent, compared to the sum of those densities generated in NS DBD and AC DBD operated individually. The production of O3 and N2O is modulated significantly by the phase in which the nanosecond pulse is superimposed. The density increase and modulation effects by the nanosecond pulse are found to correspond with the electrical charge transport and the excess electrical charge accumulation induced by the nanosecond pulse. It is suggested that the electrical charge transport by the nanosecond pulse might result in the enhancement of the nanosecond pulse current, which may lead to more efficient molecular dissociation, and the excess electrical charge accumulation induced by the nanosecond pulse increases the discharge coupling power which would enhance molecular dissociation.

A distributed parameter model of transmission line transformer for high voltage nanosecond pulse generation.

Science.gov (United States)

Li, Jiangtao; Zhao, Zheng; Li, Longjie; He, Jiaxin; Li, Chenjie; Wang, Yifeng; Su, Can

2017-09-01

A transmission line transformer has potential advantages for nanosecond pulse generation including excellent frequency response and no leakage inductance. The wave propagation process in a secondary mode line is indispensable due to an obvious inside transient electromagnetic transition in this scenario. The equivalent model of the transmission line transformer is crucial for predicting the output waveform and evaluating the effects of magnetic cores on output performance. However, traditional lumped parameter models are not sufficient for nanosecond pulse generation due to the natural neglect of wave propagations in secondary mode lines based on a lumped parameter assumption. In this paper, a distributed parameter model of transmission line transformer was established to investigate wave propagation in the secondary mode line and its influential factors through theoretical analysis and experimental verification. The wave propagation discontinuity in the secondary mode line induced by magnetic cores is emphasized. Characteristics of the magnetic core under a nanosecond pulse were obtained by experiments. Distribution and formation of the secondary mode current were determined for revealing essential wave propagation processes in secondary mode lines. The output waveform and efficiency were found to be affected dramatically by wave propagation discontinuity in secondary mode lines induced by magnetic cores. The proposed distributed parameter model was proved more suitable for nanosecond pulse generation in aspects of secondary mode current, output efficiency, and output waveform. In depth, comprehension of underlying mechanisms and a broader view of the working principle of the transmission line transformer for nanosecond pulse generation can be obtained through this research.

Frequency and seasonality of flash floods in Slovenia

Directory of Open Access Journals (Sweden)

Trobec Tajan

2017-01-01

Full Text Available The purpose of this paper is to assess and analyse the dynamics of flash flooding events in Slovenia. The paper examines in particular the frequency of flash floods and their seasonal distribution. The methodology is based on the analysis of historical records and modern flood data. The results of a long-term frequency analysis of 138 flash floods that occurred between 1550 and 2015 are presented. Because of the lack of adequate historical flood data prior to 1950 the main analysis is based on data for the periodbetween1951 and2015, while the analysis of data for the period between1550 and1950 is added as a supplement to the main analysis. Analysis of data for the period after 1950 shows that on average 1.3 flash floods occur each year in Slovenia. The linear trend for the number of flash floods is increasing but is not statistically significant. Despite the fact that the majority of Slovenian rivers have one of the peaks in spring and one of the lows in summer, 90% of flash floods actually occur during meteorological summer or autumn - i.e. between June and November, which shows that discharge regimes and flood regimes are not necessarily related. Because of the lack of flood records from the more distant past as well as the large variability of flash flood events in the last several decades, we cannot provide a definitive answer to the question about possible changes in their frequency and seasonality by relying solely on the detected trends. Nevertheless, considering the results of analysis and future climate change scenarios the frequency of flash floods in Slovenia could increase while the period of flash flood occurrence could be extended.

Dynamic of ozone formation in nanosecond microwave discharges

International Nuclear Information System (INIS)

Akhmedzhanov, R.A.; Vikharev, A.L.; Gorbachev, A.M.

1995-01-01

Nanosecond gas discharges are efficient sources of chemically active plasma. Studies of the nanosecond microwave discharge are interesting for remote modification of the chemical composition of the atmosphere in term of its purification, for diagnostics of impurities and ozone replenishment in the regions of local open-quotes ozone holesclose quotes. In this connection a study of plasma chemical processes in such a discharge seems appropriate, as well as modeling of ecological consequences of the effect of powerful microwave radiation on the atmosphere. The present paper contains generalized results of studying the process of ozone formation in a pulse-periodic freely localized nanosecond microwave discharge. The experiments were performed in a wide range of parameters: microwave radiation wavelength λ = 0.8 and 3cm, pulse duration τ = 6 and 500ns, pulse power P = 50kW and 20MW, pulse repetition rate F = 1-10 3 Hz. The working gases were air and oxygen under pressure P = 10-100Torr. As a source of the microwave radiation a pulse magnetron was used with a device for pulse compression based on the waveguide resonator, and a relativistic microwave generator. The discharge was produced in the focus of the parabolic mirror and had the form of homogeneous cylinder. The plasma chemical processes were studied in two cases. The discharge was created either in the quartz tube placed along the focal line of the mirror or in the free air. Dynamics of formation of ozone and nitrogen oxides in the discharge was studied by means of absorption spectroscopy in the regime of accumulation of the products of chemical reactions (in a closed volume) and their diffusion spreading

Dynamical propagation of nanosecond pulses in Naphthalocyanines and Phthalocyanines

Energy Technology Data Exchange (ETDEWEB)

Miao, Quan, E-mail: qmiao2013@yahoo.com [College of Electronics, Communication and Physics, Shandong University of Science and Technology, Qingdao 266590, Shandong (China); Liang, Min; Liu, Qixin [College of Electronics, Communication and Physics, Shandong University of Science and Technology, Qingdao 266590, Shandong (China); College of Electrical Engineering and Automation, Shandong University of Science and Technology, Qingdao 266590, Shandong (China); Wang, Jing-Jing [College of Electronics, Communication and Physics, Shandong University of Science and Technology, Qingdao 266590, Shandong (China); Sun, Erping; Xu, Yan [College of Electronics, Communication and Physics, Shandong University of Science and Technology, Qingdao 266590, Shandong (China); College of Electrical Engineering and Automation, Shandong University of Science and Technology, Qingdao 266590, Shandong (China)

2016-11-30

Highlights: • We study the dynamical processes of nanoseconds lasers in Naphthalocyanines and Phthalocyanines. • We provide theoretical evidences of the main mechanism of optical power limiting. • The central metals play more important roles in the dynamical processes. • The main reason is the central metals enhance the spin–orbit coupling. - Abstract: Dynamical propagation and optical limiting of nanosecond pulses in peripherally substituted Naphthalocyanines (Npcs) and Phthalocyanines (Pcs) with central metals gallium and indium were theoretically studied using paraxial field and rate equations. The results demonstrated that both Npcs and Pcs have good optical limiting performances, and Npc with heavier central mental indium shows better optical limiting properities due to the stronger reverse saturable absorption, which is mainly strengthened by the larger one-photo absorption cross section of excited state and the faster intersystem crossing rate.

Nanosecond electric pulses trigger actin responses in plant cells

International Nuclear Information System (INIS)

Berghoefer, Thomas; Eing, Christian; Flickinger, Bianca; Hohenberger, Petra; Wegner, Lars H.; Frey, Wolfgang; Nick, Peter

2009-01-01

We have analyzed the cellular effects of nanosecond pulsed electrical fields on plant cells using fluorescently tagged marker lines in the tobacco cell line BY-2 and confocal laser scanning microscopy. We observe a disintegration of the cytoskeleton in the cell cortex, followed by contraction of actin filaments towards the nucleus, and disintegration of the nuclear envelope. These responses are accompanied by irreversible permeabilization of the plasma membrane manifest as uptake of Trypan Blue. By pretreatment with the actin-stabilizing drug phalloidin, the detachment of transvacuolar actin from the cell periphery can be suppressed, and this treatment can also suppress the irreversible perforation of the plasma membrane. We discuss these findings in terms of a model, where nanosecond pulsed electric fields trigger actin responses that are key events in the plant-specific form of programmed cell death.

Spin-trapping and ESR studies of the direct photolysis of aromatic amino acids, dipeptides, tripeptides and polypeptides in aqueous solutions-II. Tyrosine and related compounds

Energy Technology Data Exchange (ETDEWEB)

Lion, Y; Kuwabara, M; Riesz, P [National Cancer Inst., Bethesda, MD (USA)

1982-01-01

The UV-photolysis of peptides containing tyrosine (Tyr) was investigated in aqueous solutions at room temperature at 220 and 265 nm. The short-lived free radicals formed during photolysis were spin-trapped by t-nitrosobutane and identified by electron spin resonance. For N-acetyl-and N-formyl-L-Tyr and for peptides containing L-Tyr as the middle residue, photolysis at 265 nm under neutral conditions produced mainly spin-adducts due to the scission between the alpha carbon and the methylene group attached to the aromatic ring, while at 220 nm decarboxylation radicals were spin-trapped. Photolysis of di- and tripeptides at 275 nm in alkaline solutions predominantly generated deamination radicals. The radicals produced in the photolysis of the oxidized A chain of insulin were tentatively characterized by comparison with the results for di- and tripeptides.

Spatial-temporal characteristics of lightning flash size in a supercell storm

Science.gov (United States)

Zhang, Zhixiao; Zheng, Dong; Zhang, Yijun; Lu, Gaopeng

2017-11-01

The flash sizes of a supercell storm, in New Mexico on October 5, 2004, are studied using the observations from the New Mexico Lightning Mapping Array and the Albuquerque, New Mexico, Doppler radar (KABX). First, during the temporal evolution of the supercell, the mean flash size is anti-correlated with the flash rate, following a unary power function, with a correlation coefficient of - 0.87. In addition, the mean flash size is linearly correlated with the area of reflectivity > 30 dBZ at 5 km normalized by the flash rate, with a correlation coefficient of 0.88. Second, in the horizontal, flash size increases along the direction from the region near the convection zone to the adjacent forward anvil. The region of minimum flash size usually corresponds to the region of maximum flash initiation and extent density. The horizontal correspondence between the mean flash size and the flash extent density can also be fitted by a unary power function, and the correlation coefficient is > 0.5 in 50% of the radar volume scans. Furthermore, the quality of fit is positively correlated to the convective intensity. Third, in the vertical direction, the height of the maximum flash initiation density is close to the height of maximum flash extent density, but corresponds to the height where the mean flash size is relatively small. In the discussion, the distribution of the small and dense charge regions when and where convection is vigorous in the storm, is deduced to be responsible for the relationship that flash size is temporally and spatially anti-correlated with flash rate and density, and the convective intensity.

Menopausal Hot Flashes and Carotid Intima Media Thickness Among Midlife Women.

Science.gov (United States)

Thurston, Rebecca C; Chang, Yuefang; Barinas-Mitchell, Emma; Jennings, J Richard; Landsittel, Doug P; Santoro, Nanette; von Känel, Roland; Matthews, Karen A

2016-12-01

There has been a longstanding interest in the role of menopause and its correlates in the development of cardiovascular disease (CVD) in women. Menopausal hot flashes are experienced by most midlife women; emerging data link hot flashes to CVD risk indicators. We tested whether hot flashes, measured via state-of-the-art physiologic methods, were associated with greater subclinical atherosclerosis as assessed by carotid ultrasound. We considered the role of CVD risk factors and estradiol concentrations in these associations. A total of 295 nonsmoking women free of clinical CVD underwent ambulatory physiologic hot flash assessments; a blood draw; and carotid ultrasound measurement of intima media thickness and plaque. Associations between hot flashes and subclinical atherosclerosis were tested in regression models controlling for CVD risk factors and estradiol. More frequent physiologic hot flashes were associated with higher carotid intima media thickness (for each additional hot flash: β [SE]=0.004 [0.001]; P=0.0001; reported hot flash: β [SE]=0.008 [0.002]; P=0.002, multivariable) and plaque (eg, for each additional hot flash, odds ratio [95% confidence interval] plaque index ≥2=1.07 [1.003-1.14]; P=0.04, relative to no plaque, multivariable] among women reporting daily hot flashes; associations were not accounted for by CVD risk factors or by estradiol. Among women reporting hot flashes, hot flashes accounted for more variance in intima media thickness than most CVD risk factors. Among women reporting daily hot flashes, frequent hot flashes may provide information about a woman's vascular status beyond standard CVD risk factors and estradiol. Frequent hot flashes may mark a vulnerable vascular phenotype among midlife women. © 2016 American Heart Association, Inc.

Flood hazard assessment in areas prone to flash flooding

Science.gov (United States)

Kvočka, Davor; Falconer, Roger A.; Bray, Michaela

2016-04-01

Contemporary climate projections suggest that there will be an increase in the occurrence of high-intensity rainfall events in the future. These precipitation extremes are usually the main cause for the emergence of extreme flooding, such as flash flooding. Flash floods are among the most unpredictable, violent and fatal natural hazards in the world. Furthermore, it is expected that flash flooding will occur even more frequently in the future due to more frequent development of extreme weather events, which will greatly increase the danger to people caused by flash flooding. This being the case, there will be a need for high resolution flood hazard maps in areas susceptible to flash flooding. This study investigates what type of flood hazard assessment methods should be used for assessing the flood hazard to people caused by flash flooding. Two different types of flood hazard assessment methods were tested: (i) a widely used method based on an empirical analysis, and (ii) a new, physically based and experimentally calibrated method. Two flash flood events were considered herein, namely: the 2004 Boscastle flash flood and the 2007 Železniki flash flood. The results obtained in this study suggest that in the areas susceptible to extreme flooding, the flood hazard assessment should be conducted using methods based on a mechanics-based analysis. In comparison to standard flood hazard assessment methods, these physically based methods: (i) take into account all of the physical forces, which act on a human body in floodwater, (ii) successfully adapt to abrupt changes in the flow regime, which often occur for flash flood events, and (iii) rapidly assess a flood hazard index in a relatively short period of time.

Guiding of Long-Distance Electric Discharges by Combined Femtosecond and Nanosecond Pulses Emitted by Hybrid KrF Laser System

Science.gov (United States)

2014-01-30

laser pulse initiated HV discharge with a time delay of tens nanoseconds – evidently it is developing due to an avalanche -like growth of electron...AFRL-AFOSR-UK-TR-2014-0040 Guiding of long-distance electric discharges by combined femtosecond and nanosecond pulses emitted by...and guiding electric discharge , KrF laser, femtosecond pulse , nanosecond pulse , filamentation, plasma channel, lightning control, laser control of

Multi-photon UV photolysis of gaseous polycyclic aromatic hydrocarbons: Extinction spectra and dynamics

Energy Technology Data Exchange (ETDEWEB)

Walsh, A. J.; Gash, E. W.; Mansfield, M. W. D. [Physics Department, University College Cork, Cork (Ireland); Ruth, A. A. [Physics Department, University College Cork, Cork (Ireland); Environmental Research Institute, University College Cork, Cork (Ireland)

2013-08-07

The extinction spectra of static naphthalene and static biphenylene vapor, each buffered with a noble gas at room temperature, were measured as a function of time in the region between 390 and 850 nm after UV multi-photon laser photolysis at 308 nm. Employing incoherent broadband cavity enhanced absorption spectroscopy (IBBCEAS), the spectra were found to be unstructured with a general lack of isolated features suggesting that the extinction was not solely based on absorption but was in fact dominated by scattering from particles formed in the photolysis of the respective polycyclic aromatic hydrocarbon. Following UV multi-photon photolysis, the extinction dynamics of the static (unstirred) closed gas-phase system exhibits extraordinary quasi-periodic and complex oscillations with periods ranging from seconds to many minutes, persisting for up to several hours. Depending on buffer gas type and pressure, several types of dynamical responses could be generated (classified as types I, II, and III). They were studied as a function of temperature and chamber volume for different experimental conditions and possible explanations for the oscillations are discussed. A conclusive model for the observed phenomena has not been established. However, a number of key hypotheses have made based on the measurements in this publication: (a) Following the multi-photon UV photolysis of naphthalene (or biphenylene), particles are formed on a timescale not observable using IBBCEAS. (b) The observed temporal behavior cannot be described on basis of a chemical reaction scheme alone. (c) The pressure dependence of the system's responses is due to transport phenomena of particles in the chamber. (d) The size distribution and the refractive indices of particles are time dependent and evolve on a timescale of minutes to hours. The rate of particle coagulation, involving coalescent growth and particle agglomeration, affects the observed oscillations. (e) The walls of the chamber act as a

Flash memory management system and method utilizing multiple block list windows

Science.gov (United States)

Chow, James (Inventor); Gender, Thomas K. (Inventor)

2005-01-01

The present invention provides a flash memory management system and method with increased performance. The flash memory management system provides the ability to efficiently manage and allocate flash memory use in a way that improves reliability and longevity, while maintaining good performance levels. The flash memory management system includes a free block mechanism, a disk maintenance mechanism, and a bad block detection mechanism. The free block mechanism provides efficient sorting of free blocks to facilitate selecting low use blocks for writing. The disk maintenance mechanism provides for the ability to efficiently clean flash memory blocks during processor idle times. The bad block detection mechanism provides the ability to better detect when a block of flash memory is likely to go bad. The flash status mechanism stores information in fast access memory that describes the content and status of the data in the flash disk. The new bank detection mechanism provides the ability to automatically detect when new banks of flash memory are added to the system. Together, these mechanisms provide a flash memory management system that can improve the operational efficiency of systems that utilize flash memory.

A thermal lensing study of a photolysis of di- t-butyl peroxide

Science.gov (United States)

Fuke, K.; Hasegawa, A.; Ueda, M.; Itoh, M.

1981-11-01

A photolysis of di- t-butyl peroxide (BOOB) was studied by using a thermal lensing technique. This technique is found to be applicable to the determination Of the rate Constants of the decay of t-butoxy radical (BO ) and the hydrogen abstraction reaction.

Photoinduced reduction of the medial FeS center in the hydrogenase small subunit HupS from Nostoc punctiforme.

Science.gov (United States)

Raleiras, Patrícia; Hammarström, Leif; Lindblad, Peter; Styring, Stenbjörn; Magnuson, Ann

2015-07-01

The small subunit from the NiFe uptake hydrogenase, HupSL, in the cyanobacterium Nostoc punctiforme ATCC 29133, has been isolated in the absence of the large subunit (P. Raleiras, P. Kellers, P. Lindblad, S. Styring, A. Magnuson, J. Biol. Chem. 288 (2013) 18,345-18,352). Here, we have used flash photolysis to reduce the iron-sulfur clusters in the isolated small subunit, HupS. We used ascorbate as electron donor to the photogenerated excited state of Ru(II)-trisbipyridine (Ru(bpy)3), to generate Ru(I)(bpy)3 as reducing agent. Our results show that the isolated small subunit can be reduced by the Ru(I)(bpy)3 generated through flash photolysis. Copyright © 2015 Elsevier Inc. All rights reserved.

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 uFLIP...

Exploring Branded Flash Mobs : A study of the impact of branded flash mobs on consumer behavior and consumer experience

OpenAIRE

Grant, Philip

2014-01-01

The desire of every marketer is to develop and maintain strong customer relationships. One way this can be accomplished is through effective advertising. Marketers have recently begun to brand flash mobs as a way to effectuate strong brand relationships. Even so, it is unclear whether or not the branding of flash mobs supports or frustrates this pursuit. Therefore, the goal of this thesis is to help marketers understand the potential impact that branded flash mobs may have on consumer behavio...

Automated Studies of Continuing Current in Lightning Flashes

Science.gov (United States)

Martinez-Claros, Jose

Continuing current (CC) is a continuous luminosity in the lightning channel that lasts longer than 10 ms following a lightning return stroke to ground. Lightning flashes following CC are associated with direct damage to power lines and are thought to be responsible for causing lightning-induced forest fires. The development of an algorithm that automates continuing current detection by combining NLDN (National Lightning Detection Network) and LEFA (Langmuir Electric Field Array) datasets for CG flashes will be discussed. The algorithm was applied to thousands of cloud-to-ground (CG) flashes within 40 km of Langmuir Lab, New Mexico measured during the 2013 monsoon season. It counts the number of flashes in a single minute of data and the number of return strokes of an individual lightning flash; records the time and location of each return stroke; performs peak analysis on E-field data, and uses the slope of interstroke interval (ISI) E-field data fits to recognize whether continuing current (CC) exists within the interval. Following CC detection, duration and magnitude are measured. The longest observed C in 5588 flashes was 631 ms. The performance of the algorithm (vs. human judgement) was checked on 100 flashes. At best, the reported algorithm is "correct" 80% of the time, where correct means that multiple stations agree with each other and with a human on both the presence and duration of CC. Of the 100 flashes that were validated against human judgement, 62% were hybrid. Automated analysis detects the first but misses the second return stroke in many cases where the second return stroke is followed by long CC. This problem is also present in human interpretation of field change records.

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

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.

Flash hydropyrolysis of bituminous coal . III. Research on flash hydropyrolysis tar

Energy Technology Data Exchange (ETDEWEB)

Dong, M.; Zhu, Z.; He, Y.; Ding, N.; Tang, L. [East China University of Science and Technology, Shanghai (China)

2000-02-01

Tar sample obtained by flash hydropyrolysis (FHP) from Dongshen coal at high pressure entrained reactor was investigated. An effect of flash hydropyrolysis temperature on the main components in tar was studied and the quality of the tar was compared with high temperature coke oven tar. The results showed that: the yields of liquid hydrocarbon in FHP tar were more than 15%, which is twofold of that in coke oven tar; the FHP tar has high oil fraction and low pitch; high phenol components and pure condensed polycyclic aromatic hydrocarbon, and low aliphatic hydrocarbon. The components of the FHP tar were simpler than that of high temperature coke oven tar. Therefore, FHP has improved the quantity and quality of tar. 11 refs., 3 figs., 5 tabs.

Improving Flash Flood Prediction in Multiple Environments

Science.gov (United States)

Broxton, P. D.; Troch, P. A.; Schaffner, M.; Unkrich, C.; Goodrich, D.; Wagener, T.; Yatheendradas, S.

2009-12-01

Flash flooding is a major concern in many fast responding headwater catchments . There are many efforts to model and to predict these flood events, though it is not currently possible to adequately predict the nature of flash flood events with a single model, and furthermore, many of these efforts do not even consider snow, which can, by itself, or in combination with rainfall events, cause destructive floods. The current research is aimed at broadening the applicability of flash flood modeling. Specifically, we will take a state of the art flash flood model that is designed to work with warm season precipitation in arid environments, the KINematic runoff and EROSion model (KINEROS2), and combine it with a continuous subsurface flow model and an energy balance snow model. This should improve its predictive capacity in humid environments where lateral subsurface flow significantly contributes to streamflow, and it will make possible the prediction of flooding events that involve rain-on-snow or rapid snowmelt. By modeling changes in the hydrologic state of a catchment before a flood begins, we can also better understand the factors or combination of factors that are necessary to produce large floods. Broadening the applicability of an already state of the art flash flood model, such as KINEROS2, is logical because flash floods can occur in all types of environments, and it may lead to better predictions, which are necessary to preserve life and property.

Photoemission in nanosecond and picosecond regimes obtained from macro and micro cathodes

International Nuclear Information System (INIS)

Boussoukaya, M.; Bergeret, H.; Chehab, R.; Leblond, B.; Franco, M.

1987-03-01

For Lasertron studies at LAL, results obtained from tests on different photocathodes are given below. Using respectively two Nd: YAG lasers (a nanosecond one and a picosecond one) we have determined the level and the intensity of pulsed photoemission and the photoelectric yield in UV, green and infrared lights. We obtained a total current of more than 1 A with nanosecond width from a single W needle, and photoconversion yield of more than 1 was reached in green and UV lights. In classical pulsed photoemission, obtained photoconversion yield from LaB 6 photocathode was of about 10 -3 in higher fields

Flash flood modelling for ungauged catchments

Science.gov (United States)

Garambois, P.-A.; Roux, H.; Larnier, K.; Dartus, D.

2012-04-01

Flash flood is a very intense and quick hydrologic response of a catchment to rainfall. This phenomenon has a high spatial-temporal variability as its generating storm, often hitting small catchments (few km2). Data collected by (Gaume et al. 2009) about 500 flash floods over the last 50 years showed that they could occur everywhere in Europe and more often in the Mediterranean regions, Alpine regions and continental Europe. Given the small spatial-temporal scales and high variability of flash floods, their prediction remains a hard exercise as the necessary data are often scarce. Flash flood prediction on ungauged catchments is one of the challenges of hydrological modelling as defined by (Sivapalan et al. 2003). Several studies have been headed up with the MARINE model (Modélisation de l'Anticipation du Ruissellement et des Inondations pour des évèNements Extrêmes) for the Gard region (France), (Roux et al. 2011), (Castaings et al. 2009). This physically based spatially distributed rainfall runoff model is dedicated to flash flood prediction. The study aims at finding a methodology for flash flood prediction at ungauged locations in the Cévennes-Vivarais region in particular. The regionalization method is based on multiple calibrations on gauged catchments in order to extract model structures (model + parameter values) for each catchment. Several mathematical methods (multiple regressions, transfer functions, krigging…) will then be tested to calculate a regional parameter set. The study also investigates the usability of additional hydrologic indices at different time scales to constrain model predictions from parameters obtained using these indices, and this independently of the model considered. These hydrologic indices gather information on hydrograph shape or catchment dynamic for instance. Results explaining global catchments behaviour are expected that way. The spatial-temporal variability of storms is also described through indices and linked with

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

An unusual characteristic “flower-like” pattern: flash suppressor burns

OpenAIRE

Gurcan, Altun

2012-01-01

The case on contact shots from firearms with a flash suppressor is rare. When a rifle fitted with a flash suppressor is fired, the emerging soot-laden gas in the barrel escapes from the slits of the flash suppressor. If the shot is contact or near contact, the flash suppressor will produce a characteristic “flower-like” pattern of seared, blackened zones around the entrance. This paper presents the injury pattern of the flash suppressor in a 29-year-old man who committed suicide with a G3 aut...

An unusual characteristic “flower-like” pattern: flash suppressor burns

Science.gov (United States)

Gurcan, Altun

2012-01-01

The case on contact shots from firearms with a flash suppressor is rare. When a rifle fitted with a flash suppressor is fired, the emerging soot-laden gas in the barrel escapes from the slits of the flash suppressor. If the shot is contact or near contact, the flash suppressor will produce a characteristic “flower-like” pattern of seared, blackened zones around the entrance. This paper presents the injury pattern of the flash suppressor in a 29-year-old man who committed suicide with a G3 automatic infantry rifle. PMID:23935280

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.

Replacing HDDs with Solid-State Flash Disks in PXIbus-Based Systems

International Nuclear Information System (INIS)

Zhao, Z W; Zeng, L

2006-01-01

New security features, constantly decreasing prices, solid-state Flash disks are becoming a popular alternative for replacing failure-prone mechanical Hard Disk Drives (HDDs) in PXIbus-based military systems. The key component in high-capacity solid-state Flash disks is NAND Flash, but with a specification that shows only 100,000-300,000 write/erase cycles, engineers may be concerned that the lifetime of Flash disks cannot meet their application requirements. With the right Flash management, Flash disks are able to provide the reliability and endurance that military applications need

NELIOTA: First temperature measurement of lunar impact flashes

Science.gov (United States)

Bonanos, A. Z.; Avdellidou, C.; Liakos, A.; Xilouris, E. M.; Dapergolas, A.; Koschny, D.; Bellas-Velidis, I.; Boumis, P.; Charmandaris, V.; Fytsilis, A.; Maroussis, A.

2018-04-01

We report the first scientific results from the NELIOTA (NEO Lunar Impacts and Optical TrAnsients) project, which has recently begun lunar monitoring observations with the 1.2-m Kryoneri telescope. NELIOTA aims to detect faint impact flashes produced by near-Earth meteoroids and asteroids and thereby help constrain the size-frequency distribution of near-Earth objects in the decimeter to meter range. The NELIOTA setup, consisting of two fast-frame cameras observing simultaneously in the R and I bands, enables - for the first time - direct analytical calculation of the flash temperatures. We present the first ten flashes detected, for which we find temperatures in the range 1600 to 3100 K, in agreement with theoretical values. Two of these flashes were detected on multiple frames in both filters and therefore yield the first measurements of the temperature drop for lunar flashes. In addition, we compute the impactor masses, which range between 100 g and 50 kg.

Cardiac autonomic function and hot flashes among perimenopausal and postmenopausal women.

Science.gov (United States)

Gibson, Carolyn J; Mendes, Wendy Berry; Schembri, Michael; Grady, Deborah; Huang, Alison J

2017-07-01

Abnormalities in autonomic function are posited to play a pathophysiologic role in menopausal hot flashes. We examined relationships between resting cardiac autonomic activity and hot flashes in perimenopausal and postmenopausal women. Autonomic function was assessed at baseline and 12 weeks among perimenopausal and postmenopausal women (n = 121, mean age 53 years) in a randomized trial of slow-paced respiration for hot flashes. Pre-ejection period (PEP), a marker of sympathetic activation, was measured with impedance cardiography. Respiratory sinus arrhythmia (RSA), a marker of parasympathetic activation, was measured with electrocardiography. Participants self-reported hot flash frequency and severity in 7-day symptom diaries. Analysis of covariance models were used to relate autonomic function and hot flash frequency and severity at baseline, and to relate changes in autonomic function to changes in hot flash frequency and severity over 12 weeks, adjusting for age, body mass index, and intervention assignment. PEP was not associated with hot flash frequency or severity at baseline or over 12 weeks (P > 0.05 for all). In contrast, there was a trend toward greater frequency of moderate-to-severe hot flashes with higher RSA at baseline (β = 0.43, P = 0.06), and a positive association between change in RSA and change in frequency of moderate-to-severe hot flashes over 12 weeks (β = 0.63, P = 0.04). Among perimenopausal and postmenopausal women with hot flashes, variations in hot flash frequency and severity were not explained by variations in resting sympathetic activation. Greater parasympathetic activation was associated with more frequent moderate-to-severe hot flashes, which may reflect increased sensitivity to perceiving hot flashes.

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

Quad nanosecond delay module

International Nuclear Information System (INIS)

McDonald, R.J.; Hunter, J.B.; Wozniak, G.J.

1986-04-01

Four nanosecond (ns) delay units have been designed to fit in a single-width NIM module. This module is particularly suited for use in conjunction with quad constant fraction timing discriminators (CFTDs) since it has four delay units that can be placed adjacent to the four units of the CFTD. A series of different length cables connected via DIP toggle switches provide delays of 0.60 ns in 4 ns increments. Thus, the CFTD delay can be optimized for pulses of different rise times from approx.10-100 ns. Design work for the PC board and silkscreening of the front panel were done with the MacDraw program on the Apple Mackintosh computer and printed with the Lasewriter printer. 6 refs

High power semiconductor switching in the nanosecond regime

International Nuclear Information System (INIS)

Zucker, O.S.; Long, J.R.; Smith, V.L.; Page, D.J.; Roberts, J.S.

1975-12-01

Light activated multilayered silicon semiconductor devices have been used to switch at megawatt power levels with nanosecond turnon time. Current rate of rise of 700 kA/μs at 10 kA, with 1 kV across the load have been achieved. Recovery time of 1 millisec has been obtained. Applicability to fusion research needs is discussed

RURAL FLASH-FLOOD BEHAVIOR IN GOUYAVE WATERSHED, GRENADA, CARIBBEAN ISLAND

Directory of Open Access Journals (Sweden)

Rahmat Aris Pratomo

2016-10-01

Full Text Available Flash-flood is considered as one of the most common natural disasters in Grenada, a tropical small state island in Caribbean Island. Grenada has several areas which are susceptible to flooding. One of them is Gouyave town which is located in the north-west of Grenada. Its land-use types are highly dominated by green areas, especially in the upper-part of the region. The built-up areas can only be found in the lower-part of Gouyave watershed, near the coastal area. However, there were many land conversions from natural land-use types into built-up areas in the upper-part region. They affected the decrease of water infiltration and the increase of potential run-off, making these areas susceptible to flash-flood. In addition, it is also influenced by the phenomenon of climate change. Changes in extreme temperature increase higher potential of hurricanes or wind-storm, directly related to the potential escalation of flash-flood. To develop effective mitigation strategies, understanding the behavior of flash-flood is required. The purpose of this paper was to observe the behavior of flash-flood in Gouyave watershed in various return periods using OpenLISEM software. It was used to develop and analyse the flash-flood characteristics. The result showed that the climatic condition (rainfall intensity and land-use are influential to the flash-flood event. Flash-flood occurs in 35 and 100 years return period. Flash-flood inundates Gouyave’s area in long duration, with below 1 m flood depth. The flood propagation time is slow. This condition is also influenced by the narrower and longer of Gouyave basin shape. To develop flash-flood reduction strategies, the overall understanding of flash-flood behavior is important. If the mitigation strategy is adapted to their behavior, the implementation will be more optimum.

Professional Flash Mobile Development Creating Android and iPhone Applications

CERN Document Server

Wagner, Richard

2010-01-01

Professional Flash Mobile Development: Creating Android and iPhone ApplicationsEverything Flash developers need to know to create native Android and iPhone appsThis Wrox guide shows Flash developers how to create native applications for Android and iPhone mobile devices using Flash. Packed with practical examples, it shows how to build a variety of apps and integrate them with core mobile services such as Accelerometer, GPS, Photo Library,and more.Offers Flash developers the tools to create apps for the Android and iPhone mobile devicesSho

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.

Sub-nanosecond time-of-flight for segmented silicon detectors

International Nuclear Information System (INIS)

Souza, R.T. de; Alexander, A.; Brown, K.; Floyd, B.; Gosser, Z.Q.; Hudan, S.; Poehlman, J.; Rudolph, M.J.

2011-01-01

Development of a multichannel time-of-flight system for readout of a segmented, ion-passivated, ion-implanted silicon detector is described. This system provides sub-nanosecond resolution (δt∼370ps) even for low energy α particles which deposit E≤7.687MeV in the detector.

Degradation mechanisms of Microcystin-LR during UV-B photolysis and UV/H2O2 processes: Byproducts and pathways.

Science.gov (United States)

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

2017-10-01

The removal and degradation pathways of microcystin-LR (MC-LR, [M+H] +  = 995.6) in UV-B photolysis and UV-B/H 2 O 2 processes were examined using liquid chromatography-tandem mass spectrometry. The UV/H 2 O 2 process was more efficient than UV-B photolysis for MC-LR removal. Eight by-products were newly identified in the UV-B photolysis ([M+H] +  = 414.3, 417.3, 709.6, 428.9, 608.6, 847.5, 807.4, and 823.6), and eleven by-products were identified in the UV-B/H 2 O 2 process ([M+H] +  = 707.4, 414.7, 429.3, 445.3, 608.6, 1052.0, 313.4, 823.6, 357.3, 245.2, and 805.7). Most of the MC-LR by-products had lower [M+H] + values than the MC-LR itself during both processes, except for the [M+H] + value of 1052.0 during UV-B photolysis. Based on identified by-products and peak area patterns, we proposed potential degradation pathways during the two processes. Bond cleavage and intramolecular electron rearrangement by electron pair in the nitrogen atom were the major reactions during UV-B photolysis and UV-B/H 2 O 2 processes, and hydroxylation by OH radical and the adduct formation reaction between the produced by-products were identified as additional pathways during the UV-B/H 2 O 2 process. Meanwhile, the degradation by-products identified from MC-LR during UV-B/H 2 O 2 process can be further degraded by increasing H 2 O 2 dose. Copyright © 2017 Elsevier Ltd. All rights reserved.

A hybrid ferroelectric-flash memory cells

Science.gov (United States)

Park, Jae Hyo; Byun, Chang Woo; Seok, Ki Hwan; Kim, Hyung Yoon; Chae, Hee Jae; Lee, Sol Kyu; Son, Se Wan; Ahn, Donghwan; Joo, Seung Ki

2014-09-01

A ferroelectric-flash (F-flash) memory cells having a metal-ferroelectric-nitride-oxynitride-silicon structure are demonstrated, and the ferroelectric materials were perovskite-dominated Pb(Zr,Ti)O3 (PZT) crystallized by Pt gate electrode. The PZT thin-film as a blocking layer improves electrical and memorial performance where programming and erasing mechanism are different from the metal-ferroelectric-insulator-semiconductor device or the conventional silicon-oxide-nitride-oxide-silicon device. F-flash cells exhibit not only the excellent electrical transistor performance, having 442.7 cm2 V-1 s-1 of field-effect mobility, 190 mV dec-1 of substhreshold slope, and 8 × 105 on/off drain current ratio, but also a high reliable memory characteristics, having a large memory window (6.5 V), low-operating voltage (0 to -5 V), faster P/E switching speed (50/500 μs), long retention time (>10 years), and excellent fatigue P/E cycle (>105) due to the boosting effect, amplification effect, and energy band distortion of nitride from the large polarization. All these characteristics correspond to the best performances among conventional flash cells reported so far.

Monopole patch antenna for in vivo exposure to nanosecond pulsed electric fields.

Science.gov (United States)

Merla, C; Apollonio, F; Paffi, A; Marino, C; Vernier, P T; Liberti, M

2017-07-01

To explore the promising therapeutic applications of short nanosecond electric pulses, in vitro and in vivo experiments are highly required. In this paper, an exposure system based on monopole patch antenna is reported to perform in vivo experiments on newborn mice with both monopolar and bipolar nanosecond signals. Analytical design and numerical simulations of the antenna in air were carried out as well as experimental characterizations in term of scattering parameter (S 11 ) and spatial electric field distribution. Numerical dosimetry of the setup with four newborn mice properly placed in proximity of the antenna patch was carried out, exploiting a matching technique to decrease the reflections due to dielectric discontinuities (i.e., from air to mouse tissues). Such technique consists in the use of a matching dielectric box with dielectric permittivity similar to those of the mice. The average computed electric field inside single mice was homogeneous (better than 68 %) with an efficiency higher than 20 V m -1  V -1 for the four exposed mice. These results demonstrate the possibility of a multiple (four) exposure of small animals to short nanosecond pulses (both monopolar and bipolar) in a controlled and efficient way.

PENGEMBANGAN EVALUASI PEMBELAJARAN BERBASIS MULTIMEDIA DENGAN FLASH, PHP, DAN MySQL

Directory of Open Access Journals (Sweden)

Hadi Sutopo

2012-01-01

Full Text Available Computer-Based Testing (CBT program was launched for years to give test takers the options of taking computerized version of test. The application which generates academic score is developed as a server-side with Adobe Flash. Flash is well known as a powerful and dynamic front-end for the Web. However, Flash is also great interface for server-side applications. PHP can launch server-side script using Flash as a front-end and pass variables back and forth between Flash and the PHP pages. Along with PHP, MySQL can be used to store data and later retrieve it. Using Flash as a front-end, data and variables are passed between the MySQL database, PHP, and Flash to enhance application's functionality in managing databases.

Inhibition of Neutral Red Photolysis with Different Antioxidants

Directory of Open Access Journals (Sweden)

Zlatan Rimpapa

2007-02-01

Full Text Available 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 redphotolysis 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.

History of hot flashes and aortic calcification among postmenopausal women.

Science.gov (United States)

Thurston, Rebecca C; Kuller, Lewis H; Edmundowicz, Daniel; Matthews, Karen A

2010-03-01

Menopausal hot flashes are considered largely a quality-of-life issue. However, emerging research also links hot flashes to cardiovascular risk. In some investigations, this risk is particularly apparent among women using hormone therapy. The aim of this study was to determine whether a longer history of reported hot flashes over the study period was associated with greater aortic and coronary artery calcification. Interactions with hormone therapy use were examined in an exploratory fashion. Participants included 302 women participating in the Healthy Women Study, a longitudinal study of cardiovascular risk during perimenopause and postmenopause, which was initiated in 1983. Hot flashes (any/none) were assessed when women were 1, 2, 5, and 8 years postmenopausal. Electron beam tomography measures of coronary artery calcification and aortic calcification were completed in 1997-2004. Associations between the number of visits with report of hot flashes, divided by the number of visits attended, and aortic or coronary artery calcification (transformed) were examined in linear regression models. Interactions by hormone therapy use were evaluated. Among women using hormone therapy, a longer history of reported hot flashes was associated with increased aortic calcification, controlling for traditional cardiovascular risk factors (b = 2.87, SE = 1.21, P history of hot flashes and coronary artery calcification. Among postmenopausal women using hormone therapy, a longer history of reported hot flashes measured prospectively was associated with increased aortic calcification, controlling for traditional cardiovascular risk factors. Hot flashes may signal adverse cardiovascular changes among certain postmenopausal women.

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.

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.

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.

Influence of satellite-derived photolysis rates and NOx emissions on Texas ozone modeling

Science.gov (United States)

Tang, W.; Cohan, D. S.; Pour-Biazar, A.; Lamsal, L. N.; White, A. T.; Xiao, X.; Zhou, W.; Henderson, B. H.; Lash, B. F.

2015-02-01

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 (VCDs) is further reduced by increasing modeled NOx lifetime and adding an artificial amount of NO2 in the upper troposphere. The region-based DKF inversion suggests increasing NOx emissions by 10-50% in most regions, deteriorating the model performance in predicting ground NO2 and O3, while the sector-based DKF inversion tends to scale down area and nonroad 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 sector-based inversion-constrained 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, increases the model

The effect of clouds on photolysis rates and ozone formation in the unpolluted troposphere

Science.gov (United States)

Thompson, A. M.

1984-01-01

The photochemistry of the lower atmosphere is sensitive to short- and long-term meteorological effects; accurate modeling therefore requires photolysis rates for trace gases which reflect this variability. As an example, the influence of clouds on the production of tropospheric ozone has been investigated, using a modification of Luther's two-stream radiation scheme to calculate cloud-perturbed photolysis rates in a one-dimensional photochemical transport model. In the unpolluted troposphere, where stratospheric inputs of odd nitrogen appear to represent the photochemical source of O3, strong cloud reflectance increases the concentration of NO in the upper troposphere, leading to greatly enhanced rates of ozone formation. Although the rate of these processes is too slow to verify by observation, the calculation is useful in distinguishing some features of the chemistry of regions of differing mean cloudiness.

Nanosecond UV lasers stimulate transient Ca2+ elevations in human hNT astrocytes.

Science.gov (United States)

Raos, B J; Graham, E S; Unsworth, C P

2017-06-01

Astrocytes respond to various stimuli resulting in intracellular Ca 2+ signals that can propagate through organized functional networks. Recent literature calls for the development of techniques that can stimulate astrocytes in a fast and highly localized manner to emulate more closely the characteristics of astrocytic Ca 2+ signals in vivo. In this article we demonstrate, for the first time, how nanosecond UV lasers are capable of reproducibly stimulating Ca 2+ transients in human hNT astrocytes. We report that laser pulses with a beam energy of 4-29 µJ generate transient increases in cytosolic Ca 2+ . These Ca 2+ transients then propagate to adjacent astrocytes as intercellular Ca 2+ waves. We propose that nanosecond laser stimulation provides a valuable tool for enabling the study of Ca 2+ dynamics in human astrocytes at both a single cell and network level. Compared to previously developed techniques nanosecond laser stimulation has the advantage of not requiring loading of photo-caged or -sensitising agents, is non-contact, enables stimulation with a high spatiotemporal resolution and is comparatively cost effective.

Fiber Coupled Pulse Shaper for Sub-Nanosecond Pulse Lidar, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — This Small Business Innovation Research Phase II effort will develop an all-diode laser and fiber optic based, single frequency, sub-nanosecond pulsed laser source...

Nanosecond-Timescale Intra-Bunch-Train Feedback for the Linear Collider: Results of the FONT2 Run

International Nuclear Information System (INIS)

Barlow, R.; Dufau, M.; Kalinin, A.; Daresbury; Myatt, G.; Perry, C.; Oxford U.; Burrows, P.N.; Hartin, T.; Hussain, S.M.; Molloy, S.; White, G.R.; Queen Mary, U. of London; Adolphsen, C.; Frisch, J.C.; Hendrickson, L.; Jobe, R.K.; Markiewicz, T.; McCormick, D.J.; Nelson, J.; Ross, M.C.; Smith, S.; Smith, T.J.; SLAC

2005-01-01

We report on experimental results from the December 2003/January 2004 data run of the Feedback On Nanosecond Timescales (FONT) experiment at the Next Linear Collider Test Accelerator at SLAC. We built a second-generation prototype intra-train beam-based feedback system incorporating beam position monitors, fast analogue signal processors, a feedback circuit, fast-risetime amplifiers and stripline kickers. We applied a novel real-time charge-normalization scheme to account for beam current variations along the train. We used the system to correct the position of the 170-nanosecond-long bunchtrain at NLCTA. We achieved a latency of 53 nanoseconds, representing a significant improvement on FONT1 (2002), and providing a demonstration of intra-train feedback for the Linear Collider

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.

Low-dielectric layer increases nanosecond electric discharges in distilled water

KAUST Repository

Hamdan, Ahmad; Cha, Min

2016-01-01

decreasing of the energy consumption are the main goals of today’s research. Here we present an experimental study of nanosecond discharge in distilled water covered by a layer of dielectric material. We demonstrate through this paper that the discharge

Flash photolysis ESR study of photosystem II signal II/sub vf/, the physiological donor to P-680/sup +/

Energy Technology Data Exchange (ETDEWEB)

Warden, J T [Rensselaer Polytechnic Inst., Troy, NY; Blankenship, R E; Sauer, K

1976-01-01

In flash-illuminated, oxygen-evolving spinach chloroplasts and green algae, a free radical transient has been observed with spectral parameters similar to those of Signal II (g approx. = 2.0045, ..delta..H/sub pp/ approx. = 19 G). However, in contrast with ESR Signal II, the transient radical does not readily saturate even at microwave power levels of 200 mW. This species is formed most efficiently with ''red'' illumination (lambda < 680 nm) and occurs stoichiometrically in a 1:1 ratio with P-700/sup +/. The Photosystem II transient is formed in less than 100 ..mu..s and decays via first-order kinetics with a halftime of 400-900 ..mu..s. Additionally, the t/sub /sup 1///sub 2// for radical decay is temperature independent between 20 and 4/sup 0/C; however, below 4/sup 0/C the transient signal exhibits Arrhenius behavior with an activation energy of approx. 10 kcal . mol/sup -1/. Inhibition of electron transport through Photosystem II by o-phenanthroline, 3-(3,4-dichlorophenyl)-1,1-dimethylurea or reduced 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone suppresses the formation of the light-induced transient. At low concentrations (0.2 mM), 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone partially inhibits the free radical formation, however, the decay kinetics are unaltered. High concentrations of 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (1-5 mM) restore both the transient signal and electron flow through Photosystem II. These findings suggest that this ''quinoidal'' type ESR transient functions as the physiological donor to the oxidized reaction center chlorophyll, P-680/sup +/.

The design of the light-flash warning light

Science.gov (United States)

Wang, Junli

2018-05-01

In today's society, the warning light has been used widely in people's daily life and various industries and agricultures. It is important to protect people's life and security. Light-flashing warning light is a kind of warning light control equipment which can control warning light automatically open and work in the state of blinking after dark, and it can automatically shut down after the dawn. It can achieve the flashing light automatic control and dual function. At present, light-flashing warning lights are mainly used in the projects of municipal construction. It is helpful to warn people and vehicles that passed in the construction site and ensure personal safety through using light-flashing warning light. Its design is simple, its performance is stable and it is also very convince to use it.

Simultaneous high crystallinity and sub-bandgap optical absorptance in hyperdoped black silicon using nanosecond laser annealing

Energy Technology Data Exchange (ETDEWEB)

Franta, Benjamin, E-mail: bafranta@gmail.com; Pastor, David; Gandhi, Hemi H.; Aziz, Michael J.; Mazur, Eric [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Rekemeyer, Paul H.; Gradečak, Silvija [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2015-12-14

Hyperdoped black silicon fabricated with femtosecond laser irradiation has attracted interest for applications in infrared photodetectors and intermediate band photovoltaics due to its sub-bandgap optical absorptance and light-trapping surface. However, hyperdoped black silicon typically has an amorphous and polyphasic polycrystalline surface that can interfere with carrier transport, electrical rectification, and intermediate band formation. Past studies have used thermal annealing to obtain high crystallinity in hyperdoped black silicon, but thermal annealing causes a deactivation of the sub-bandgap optical absorptance. In this study, nanosecond laser annealing is used to obtain high crystallinity and remove pressure-induced phases in hyperdoped black silicon while maintaining high sub-bandgap optical absorptance and a light-trapping surface morphology. Furthermore, it is shown that nanosecond laser annealing reactivates the sub-bandgap optical absorptance of hyperdoped black silicon after deactivation by thermal annealing. Thermal annealing and nanosecond laser annealing can be combined in sequence to fabricate hyperdoped black silicon that simultaneously shows high crystallinity, high above-bandgap and sub-bandgap absorptance, and a rectifying electrical homojunction. Such nanosecond laser annealing could potentially be applied to non-equilibrium material systems beyond hyperdoped black silicon.

Towards a laser fluence dependent nanostructuring of thin Au films on Si by nanosecond laser irradiation

International Nuclear Information System (INIS)

Ruffino, F.; Pugliara, A.; Carria, E.; Romano, L.; Bongiorno, C.; Fisicaro, G.; La Magna, A.; Spinella, C.; Grimaldi, M.G.

2012-01-01

Highlights: ► Au nanoclusters are produced by nanosecond laser irradiations of thin Au film on Si. ► The shape, size, and surface density of the Au nanoclusters are tunable by laser fluence. ► The formation dynamic of the Au nanoclusters under nanosecond laser irradiation is analyzed. - Abstract: In this work, we study the nanostructuring effects of nanosecond laser irradiations on 5 nm thick Au film sputter-deposited on Si. After deposition of Au on Si substrate, nanosecond laser irradiations were performed increasing the laser fluence from 750 to 1500 mJ/cm 2 . Several analyses techniques, such as Rutherford backscattering spectrometry, scanning electron microscopy, atomic force microscopy, and transmission electron microscopy were crossed to study the morphological evolution of the Au film as a function of laser fluence. In particular, the formation of Au nanoparticles was observed. The analyses allowed a quantitative evaluation of the evolution of the nanoparticles size, surface density, and shape as a function of the laser fluence. Therefore, a control the structural properties of the Au nanoparticles is reached, for example, for applications in Si nanowires growth or plasmonics.

Initial Breakdown Pulse Amplitudes in Intracloud and Cloud-to-Ground Lightning Flashes

Science.gov (United States)

Marshall, T. C.; Smith, E. M.; Stolzenburg, M.; Karunarathne, S.; Siedlecki, R. D., II

2017-12-01

This study analyzes the largest initial breakdown (IB) pulse in flashes from three storms in Florida. The study was motivated in part by the possibility that IB pulses of IC flashes may cause of terrestrial gamma-ray flashes (TGFs). The range-normalized, zero-to-peak amplitude of the largest IB pulse within each flash was determined along with its altitude, duration, and occurrence time in the flash. Appropriate data were available for 40 intracloud (IC) and 32 cloud-to-ground (CG) flashes. Histograms of the magnitude of the largest IB pulse amplitude by flash type were similar, with mean (median) values of 1.49 (1.05) V/m for IC flashes and -1.35 (-0.87) V/m for CG flashes. The mean amplitude of the largest IC IB pulses are substantially smaller (roughly an order of magnitude smaller) than the few known pulse amplitudes of TGF events and TGF candidate events. The largest IB pulse in 30 IC flashes showed a weak inverse relation between pulse amplitude and altitude. Amplitude of the largest IB pulse for 25 CG flashes showed no altitude correlation. Duration of the largest IB pulse in ICs averaged twice as long as in CGs (96 μs versus 46 μs); all of the CG durations were <100 μs. Among the ICs, there is a positive relation between largest IB pulse duration and amplitude; the linear correlation coefficient is 0.385 with outliers excluded. The largest IB pulse in IC flashes typically occurred at a longer time after the first IB pulse (average 4.1 ms) than was the case in CG flashes (average 0.6 ms). In both flash types, the largest IB pulse was the first IB pulse in about 30% of the cases.

Numerical simulation of nanosecond-pulse electrical discharges

Science.gov (United States)

Poggie, J.; Adamovich, I.; Bisek, N.; Nishihara, M.

2013-02-01

Recent experiments with a nanosecond-pulse, dielectric barrier discharge at the stagnation point of a Mach 5 cylinder flow have demonstrated the formation of weak shock waves near the electrode edge, which propagate upstream and perturb the bow shock. This is a promising means of flow control, and understanding the detailed physics of the conversion of electrical energy into gas motion will aid in the design of efficient actuators based on the concept. In this work, a simplified configuration with planar symmetry was chosen as a vehicle to develop a physics-based model of nanosecond-pulse discharges, including realistic air kinetics, electron energy transport, and compressible bulk gas flow. A reduced plasma kinetic model (23 species and 50 processes) was developed to capture the dominant species and reactions for energy storage and thermalization in the discharge. The kinetic model included electronically and vibrationally excited species, and several species of ions and ground state neutrals. The governing equations included the Poisson equation for the electric potential, diffusion equations for each neutral species, conservation equations for each charged species, and mass-averaged conservation equations for the bulk gas flow. The results of calculations with this model highlighted the path of energy transfer in the discharge. At breakdown, the input electrical energy was transformed over a time scale on the order of 1 ns into chemical energy of ions, dissociation products, and vibrationally and electronically excited particles. About 30% of this energy was subsequently thermalized over a time scale of 10 µs. Since the thermalization time scale was faster than the acoustic time scale, the heat release led to the formation of weak shock waves originating near the sheath edge, consistent with experimental observations. The computed translational temperature rise (40 K) and nitrogen vibrational temperature rise (370 K) were of the same order of magnitude as

The echo-enabled harmonic generation options for FLASH II

International Nuclear Information System (INIS)

Deng, Haixiao; Decking, Winfried; Faatz, Bart

2011-03-01

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. (orig.)

A void distribution model-flashing flow

International Nuclear Information System (INIS)

Riznic, J.; Ishii, M.; Afgan, N.

1987-01-01

A new model for flashing flow based on wall nucleations is proposed here and the model predictions are compared with some experimental data. In order to calculate the bubble number density, the bubble number transport equation with a distributed source from the wall nucleation sites was used. Thus it was possible to avoid the usual assumption of a constant bubble number density. Comparisons of the model with the data shows that the model based on the nucleation site density correlation appears to be acceptable to describe the vapor generation in the flashing flow. For the limited data examined, the comparisons show rather satisfactory agreement without using a floating parameter to adjust the model. This result indicated that, at least for the experimental conditions considered here, the mechanistic predictions of the flashing phenomenon is possible on the present wall nucleation based model

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...

Evaluation of material dispersion using a nanosecond optical pulse radiator.

Science.gov (United States)

Horiguchi, M; Ohmori, Y; Miya, T

1979-07-01

To study the material dispersion effects on graded-index fibers, a method for measuring the material dispersion in optical glass fibers has been developed. Nanosecond pulses in the 0.5-1.7-microm region are generated by a nanosecond optical pulse radiator and grating monochromator. These pulses are injected into a GeO(2)-P(2)0(5)-doped silica graded-index fiber. Relative time delay changes between different wavelengths are used to determine material dispersion, core glass refractive index, material group index, and optimum profile parameter of the graded-index fiber. From the measured data, the optimum profile parameter on the GeO(2)-P(2)O(5)-doped silica graded-index fiber could be estimated to be 1.88 at 1.27 microm of the material dispersion free wavelength region and 1.82 at 1.55 microm of the lowest-loss wavelength region in silica-based optical fiber waveguides.

Isotopomer fractionation during photolysis of nitrous oxide by ultraviolet of 206 to 210 nm

International Nuclear Information System (INIS)

Toyoda, S.; Yoshida, N.; Suzuki, T.; Tsuji, K.; Shibuya, K.

2002-01-01

Nitrous oxide (N 2 O) is an important trace gas in the stratospheric chemistry as well as in the tropospheric radiative balance. Although there have been observations on the distribution of N 2 O in the atmosphere and its flux from individual sources, the global N 2 O budget is not fully understood. The isotopic information of N 2 O has been useful for constraining the N 2 O cycle since each source and sink has its own isotopic signature and isotope fractionation that is unique to the process. We have recently developed a method to determine isotopomers of N 2 O and showed that intramolecular distribution of 15 N is a parameter that has more fundamental and sensitive information than bulk 15 N abundance for constraining the atmospheric N 2 O budget. Here, we report the fractionation of isotopomers during ultraviolet photolysis of N 2 O in a 206 to 210 nm region. The fractionation factors are different among isotopomers and the site preference between two nitrogen isotopomers becomes larger along with the photolysis. The isotopomer fractionation factors of this representative wavelength are close to the apparent fractionation factors observed in the stratosphere indicating ultraviolet photolysis in the stratosphere is the dominant sink of N 2 O. Sources of atmospheric N 2 O including terrestrial and oceanic biological processes, agricultural activities, industrial formation and fossil fuel combustion are expected to be characterized to better constrain the global budget of N 2 O. (author)

Method for programming a flash memory

Energy Technology Data Exchange (ETDEWEB)

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.

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.

Picosecond absorption relaxation measured with nanosecond laser photoacoustics

OpenAIRE

Danielli, Amos; Favazza, Christopher P.; Maslov, Konstantin; Wang, Lihong V.

2010-01-01

Picosecond absorption relaxation—central to many disciplines—is typically measured by ultrafast (femtosecond or picosecond) pump-probe techniques, which however are restricted to optically thin and weakly scattering materials or require artificial sample preparation. Here, we developed a reflection-mode relaxation photoacoustic microscope based on a nanosecond laser and measured picosecond absorption relaxation times. The relaxation times of oxygenated and deoxygenated hemoglobin molecules, b...

Impacts of aerosol direct effects on tropospheric ozone through changes in atmospheric dynamics and photolysis rates

Science.gov (United States)

Xing, Jia; Wang, Jiandong; Mathur, Rohit; Wang, Shuxiao; Sarwar, Golam; Pleim, Jonathan; Hogrefe, Christian; Zhang, Yuqiang; Jiang, Jingkun; Wong, David C.; Hao, Jiming

2017-08-01

Aerosol direct effects (ADEs), i.e., scattering and absorption of incoming solar radiation, reduce radiation reaching the ground and the resultant photolysis attenuation can decrease ozone (O3) formation in polluted areas. One the other hand, evidence also suggests that ADE-associated cooling suppresses atmospheric ventilation, thereby enhancing surface-level O3. Assessment of ADE impacts is thus important for understanding emission reduction strategies that seek co-benefits associated with reductions in both particulate matter and O3 levels. This study quantifies the impacts of ADEs on tropospheric ozone by using a two-way online coupled meteorology and atmospheric chemistry model, WRF-CMAQ, using a process analysis methodology. Two manifestations of ADE impacts on O3 including changes in atmospheric dynamics (ΔDynamics) and changes in photolysis rates (ΔPhotolysis) were assessed separately through multiple scenario simulations for January and July of 2013 over China. Results suggest that ADEs reduced surface daily maxima 1 h O3 (DM1O3) in China by up to 39 µg m-3 through the combination of ΔDynamics and ΔPhotolysis in January but enhanced surface DM1O3 by up to 4 µg m-3 in July. Increased O3 in July is largely attributed to ΔDynamics, which causes a weaker O3 sink of dry deposition and a stronger O3 source of photochemistry due to the stabilization of the atmosphere. Meanwhile, surface OH is also enhanced at noon in July, though its daytime average values are reduced in January. An increased OH chain length and a shift towards more volatile organic compound (VOC)-limited conditions are found due to ADEs in both January and July. This study suggests that reducing ADEs may have the potential risk of increasing O3 in winter, but it will benefit the reduction in maxima O3 in summer.

Desorption of deuterium from beryllium codeposits using flash heating

Energy Technology Data Exchange (ETDEWEB)

Yu, J.H., E-mail: jyu@ferp.ucsd.edu [Center for Energy Research, University of California at San Diego, La Jolla, CA 92093-0417 (United States); Baldwin, M.J.; Doerner, R.P. [Center for Energy Research, University of California at San Diego, La Jolla, CA 92093-0417 (United States); Pitts, R.A. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Smirnov, R.D. [Center for Energy Research, University of California at San Diego, La Jolla, CA 92093-0417 (United States); Xu, H.W. [General Atomics, P.O. Box 85608, San Diego, CA 92186-5608 (United States)

2013-07-15

As a result of safety concerns, limits will be placed on the allowable tritium inventory retained inside the ITER vacuum vessel. The primary motivation for the present work is to test the proposed method of removing tritium from main chamber codeposits using radiative heat flashing from controlled ITER plasma shutdowns. Detritiation of Be codeposits is studied in the PISCES-B facility using flash-heating by a 10 ms laser with up to 2 MJ/m{sup 2} of absorbed energy density. Three types of codeposits are flash-heated with layer thickness ranging from 0.1 to 1.2 μm. Less than 25% of the D in the Be layer escapes at ITER-relevant flash energy densities and with peak surface temperature up to ∼900 °C. Repetitive flashing with peak surface temperature of 400–500 °C results in an increased population of higher energy trap sites, implying that transient heating which causes appropriate surface temperature excursion redistributes D among codeposit trap sites.

Gun muzzle flash detection using a CMOS single photon avalanche diode

Science.gov (United States)

Merhav, Tomer; Savuskan, Vitali; Nemirovsky, Yael

2013-10-01

Si based sensors, in particular CMOS Image sensors, have revolutionized low cost imaging systems but to date have hardly been considered as possible candidates for gun muzzle flash detection, due to performance limitations, and low SNR in the visible spectrum. In this study, a CMOS Single Photon Avalanche Diode (SPAD) module is used to record and sample muzzle flash events in the visible spectrum, from representative weapons, common on the modern battlefield. SPADs possess two crucial properties for muzzle flash imaging - Namely, very high photon detection sensitivity, coupled with a unique ability to convert the optical signal to a digital signal at the source pixel, thus practically eliminating readout noise. This enables high sampling frequencies in the kilohertz range without SNR degradation, in contrast to regular CMOS image sensors. To date, the SPAD has not been utilized for flash detection in an uncontrolled environment, such as gun muzzle flash detection. Gun propellant manufacturers use alkali salts to suppress secondary flashes ignited during the muzzle flash event. Common alkali salts are compounds based on Potassium or Sodium, with spectral emission lines around 769nm and 589nm, respectively. A narrow band filter around the Potassium emission doublet is used in this study to favor the muzzle flash signal over solar radiation. This research will demonstrate the SPAD's ability to accurately sample and reconstruct the temporal behavior of the muzzle flash in the visible wavelength under the specified imaging conditions. The reconstructed signal is clearly distinguishable from background clutter, through exploitation of flash temporal characteristics.

Flash x-ray cinematography

International Nuclear Information System (INIS)

Stein, W.E.

1976-01-01

Experiments intended to provide an overview of the potential capabilities and limitations of flash x-ray cinematography as a diagnostic technique for a Fast Reactor Safety Test Facility are described. The results provide estimates of the x-ray pulse intensity required to obtain adequate radiographs of an array of fuel pins in a typical reactor configuration. An estimate of the upper limit on the pulse duration imposed by the reactor background radiation was also determined. X-ray cinematography has been demonstrated at a repetition rate limited only by the recording equipment on hand at the time of these measurements. These preliminary results indicate that flash x-ray cinematography of the motion of fuel in a Fast Reactor Test Facility is technically feasible

Phototoxic effects of commercial photographic flash lamp on rat eyes.

Science.gov (United States)

Inoue, Makoto; Shinoda, Kei; Ohde, Hisao; Tezuka, Keiji; Hida, Tetsuo

2006-11-01

To determine whether exposure of the cornea and retina of rats to flashes from a commercial photographic flash lamp is phototoxic. Sprague-Dawley rats were exposed to 10, 100, or 1,000 flashes of the OPTICAM 16M photographic flash lamp (Fujikoeki, Japan) placed 0.1, 1, or 3 m from the eyes. Corneal damage was assessed by a fluorescein staining score, and the retinal damage by eletroretinography (ERG) and histology before and 24 h after exposure. Exposure of the eyes to 1,000 flashes at 0.1 m increased the fluorescein staining score significantly (P = 0.009, the Mann-Whitney test). Scanning electron microscopy (SEM) of the cornea showed a detachment of the epithelial cells from the surface after this exposure. The amplitude of the a-wave was decreased significantly by 23.0% (P = 0.026) of the amplitude before the exposure, and the b-wave by 19.7% (P = 0.0478) following 1,000 flashes at 0.1 m but not by the other exposures. TUNEL-positive cells were present in the outer nuclear layer only after the extreme exposure, but no significant decrease in retinal thickness was seen under any condition. The fluorescein staining score and ERGs recovered to control levels within 1 week. Light exposure to a photographic flash lamp does not induce damage to the cornea and retina except when they are exposed to 1,000 flashes at 0.1 m.

Au Contraire: Gifted in a Flash (Mob)

Science.gov (United States)

Delisle, James R.

2012-01-01

A "flash mob" is defined by Wikipedia as "a large group of people who assemble suddenly in a public place, perform an unusual and pointless act for a brief time, then disperse." Fueled by social media and Smartphones, flash mobs have been used, primarily, as entertaining diversions by addicted techies with (apparently) tons of time on their hands.…

High-voltage nanosecond pulse shaper

International Nuclear Information System (INIS)

Kapishnikov, N.K.; Muratov, V.M.; Shatanov, A.A.

1987-01-01

A high-voltage pulse shaper with an output of up to 250 kV, a base duration of ∼ 10 nsec, and a repetition frequency of 50 pulses/sec is described. The described high-voltage nanosecond pulse shaper is designed for one-orbit extraction of an electron beam from a betatron. A diagram of the pulse shaper, which employs a single-stage generator is shown. The shaping element is a low-inductance capacitor bank of series-parallel KVI-3 (2200 pF at 10 kV) or K15-10 (4700 pF at 31.5 kV) disk ceramic capacitors. Four capacitors are connected in parallel and up to 25 are connected in series

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Laser flash photolysis studies were carried out on two types of silver nanoparticles prepared by ... Type II silver nanoparticles showed a 390 nm surface plasmon band with a shoulder at 550 nm. ... Journal of Chemical Sciences | News.

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

Nanosecond radar system based on repetitive pulsed relativistic BWO

International Nuclear Information System (INIS)

Bunkin, B.V.; Gaponov-Grekhov, A.V.; Eltchaninov, A.S.; Zagulov, F.Ya.; Korovin, S.D.; Mesyats, G.A.; Osipov, M.L.; Otlivantchik, E.A.; Petelin, M.I.; Prokhorov, A.M.

1993-01-01

The paper presents the results of studies of a nanosecond radar system based on repetitive pulsed relativistic BWO. A pulsed power repetitive accelerator producing electron beams of electron energy 500-700 keV and current 5 kA in pulses of duraction 10 ns with a repetition rate of 100 pps is described. The results of experiments with a high-voltage gas-filled spark gap and a cold-cathode vacuum diode under the conditions of high repetition rates are given. Also presented are the results of studies of a relativistic BWO operating with a wavelength of 3 cm. It is shown that for a high-current beam electron energy of 500-700 keV, the BWO efficiency can reach 35%, the microwave power being 10 9 W. A superconducting solenoid creating a magnetic field of 30 kOe was used for the formation and transportation of the high-current electron beam. In conclusion, the outcome of tests of a nanosecond radar station based on a pulsed power repetitive accelerator and a relativistic BWO is reported

Flash X-ray

International Nuclear Information System (INIS)

Sato, Eiichi

2003-01-01

Generation of quasi-monochromatic X-ray by production of weakly ionized line plasma (flash X-ray), high-speed imaging by the X-ray and high-contrast imaging by the characteristic X-ray absorption are described. The equipment for the X-ray is consisted from the high-voltage power supply and condenser, turbo molecular pump, and plasma X-ray tube. The tube has a long linear anticathode to produce the line plasma and flash X-ray at 20 kA current at maximum. X-ray spectrum is measured by the imaging plate equipped in the computed radiography system after diffracted by a LiF single crystal bender. Cu anticathode generates sharp peaks of K X-ray series. The tissue images are presented for vertebra, rabbit ear and heart, and dog heart by X-ray fluoroscopy with Ce anticathode. Generation of K-orbit characteristic X-ray with extremely low bremsstrahung is to be attempted for medical use. (N.I.)

Numerical analyses of flashing jet structure and droplet size characteristics

International Nuclear Information System (INIS)

Duan Riqiang; Jiang Shengyao; Koshizuka, Seiichi; Oka, Yoshiaki; Yamaguchi, Akira; Takata, Takashi

2006-01-01

In this paper, flashing jets are numerically simulated using the MPS method. The boiling mode for flashing is identified as surface boiling mode, based on the postulation of jets from a short nozzle under high depressurization. The Homogeneous Non-equilibrium Relaxation Model (HRM) is used for calculating the evaporation rate of flashing. The numerical simulation results show that flashing jets comprise an inner intact core which is surrounded by two-phase droplet flow. The effect of degree of superheat on the jet topological geometry is investigated. With increasing degree of superheat, the topological shape of flashing jets evolves from cylindrical core for low degree of superheat to cone-shaped core for high degree of superheat, and meanwhile the extinction length comes to decrease and tends asymptotically constant as the injection temperature approaches the saturation temperature corresponding to the injection pressure. The analyses of the droplet size distribution engendered from primary breakup of flashing jets show that: two peaks exist for droplet size distribution at lower degree of superheat; however, merely one peak for higher degree of superheat. From droplet size distribution, it is revealed that the primary breakup mechanism of flashing jets can be attributed to dominant mechanical breakup mode plus enhancement via surface evaporation. (author)

49 CFR 234.253 - Flashing light units and lamp voltage.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Flashing light units and lamp voltage. 234.253... Maintenance, Inspection, and Testing Inspections and Tests § 234.253 Flashing light units and lamp voltage. (a... voltage shall be tested when installed and at least once every 12 months thereafter. (c) Each flashing...

Hydrolysis and photolysis of diacylhydrazines-type insect growth regulator JS-118 in aqueous solutions under abiotic conditions.

Science.gov (United States)

Hu, J-Y; Liu, C; Zhang, Y-C; Zheng, Z-X

2009-05-01

JS-118 is a diacylhydrazines-type insect growth regulator which is now used extensively in China. The hydrolysis and photolysis of the pesticide JS-118 in aqueous solutions have been assessed under natural and controlled conditions in this project. Hydrolysis experimental results show that JS-118 is quite stable in aqueous solutions in dark, with no significant variations be observed in degradation under various conditions. Abiotic hydrolysis is relatively unimportant compared to photolysis. The rate of photodecomposition of JS-118 in aqueous solutions follows first-order kinetics both in UV radiation and natural sunlight. The degradation rates are faster under UV light than sunlight, with the half-lives (t (1/2) = ln2/k) of 6.00-10.85 min and 6.63-10.16 day, respectively. Under UV light, two major photoproducts are detected, and tentatively identified according to HPLC-MS spectral information as N-t-butyl-N-(3,5-dimethylbenzoyl) and 3,7-dimethyl-benzoatedihydrofuran. The corresponding photolysis pathways of JS-118 are also proposed. The results obtained indicate that direct photoreaction is an important dissipation pathway of JS-118 in natural water systems.

A novel maleimide photoinitiator system

International Nuclear Information System (INIS)

Zhiyu, W.X.; Hill, D.J.T.; Hoyle, E.; Kalaraman Viswanathan

1999-01-01

This paper reports some of our recent Photo-DSC and real-time FTIR studies of the sensitization of photopolymerization processes. Investigations of the initiation mechanism using instrumental analyses including Laser flash photolysis, ESR and phosphorescence are also summarised

Interaction of gold nanoparticles with nanosecond laser pulses: Nanoparticle heating

International Nuclear Information System (INIS)

Nedyalkov, N.N.; Imamova, S.E.; Atanasov, P.A.; Toshkova, R.A.; Gardeva, E.G.; Yossifova, L.S.; Alexandrov, M.T.; Obara, M.

2011-01-01

Theoretical and experimental results on the heating process of gold nanoparticles irradiated by nanosecond laser pulses are presented. The efficiency of particle heating is demonstrated by in-vitro photothermal therapy of human tumor cells. Gold nanoparticles with diameters of 40 and 100 nm are added as colloid in the cell culture and the samples are irradiated by nanosecond pulses at wavelength of 532 nm delivered by Nd:YAG laser system. The results indicate clear cytotoxic effect of application of nanoparticle as more efficient is the case of using particles with diameter of 100 nm. The theoretical analysis of the heating process of nanoparticle interacting with laser radiation is based on the Mie scattering theory, which is used for calculation of the particle absorption coefficient, and two-dimensional heat diffusion model, which describes the particle and the surrounding medium temperature evolution. Using this model the dependence of the achieved maximal temperature in the particles on the applied laser fluence and time evolution of the particle temperature is obtained.

Interaction of gold nanoparticles with nanosecond laser pulses: Nanoparticle heating

Science.gov (United States)

Nedyalkov, N. N.; Imamova, S. E.; Atanasov, P. A.; Toshkova, R. A.; Gardeva, E. G.; Yossifova, L. S.; Alexandrov, M. T.; Obara, M.

2011-04-01

Theoretical and experimental results on the heating process of gold nanoparticles irradiated by nanosecond laser pulses are presented. The efficiency of particle heating is demonstrated by in-vitro photothermal therapy of human tumor cells. Gold nanoparticles with diameters of 40 and 100 nm are added as colloid in the cell culture and the samples are irradiated by nanosecond pulses at wavelength of 532 nm delivered by Nd:YAG laser system. The results indicate clear cytotoxic effect of application of nanoparticle as more efficient is the case of using particles with diameter of 100 nm. The theoretical analysis of the heating process of nanoparticle interacting with laser radiation is based on the Mie scattering theory, which is used for calculation of the particle absorption coefficient, and two-dimensional heat diffusion model, which describes the particle and the surrounding medium temperature evolution. Using this model the dependence of the achieved maximal temperature in the particles on the applied laser fluence and time evolution of the particle temperature is obtained.

Freeware eLearning Flash-ECG for learning electrocardiography.

Science.gov (United States)

Romanov, Kalle; Kuusi, Timo

2009-06-01

Electrocardiographic (ECG) analysis can be taught in eLearning programmes with suitable software that permits the effective use of basic tools such as a ruler and a magnifier, required for measurements. The Flash-ECG (Research & Development Unit for Medical Education, University of Helsinki, Finland) was developed to enable teachers and students to use scanned and archived ECGs on computer screens and classroom projectors. The software requires only a standard web browser with a Flash plug-in and can be integrated with learning environments (Blackboard/WebCT, Moodle). The Flash-ECG is freeware and is available to medical teachers worldwide.

Lunar Impact Flash Locations from NASA's Lunar Impact Monitoring Program

Science.gov (United States)

Moser, D. E.; Suggs, R. M.; Kupferschmidt, L.; Feldman, J.

2015-01-01

Meteoroids are small, natural bodies traveling through space, fragments from comets, asteroids, and impact debris from planets. Unlike the Earth, which has an atmosphere that slows, ablates, and disintegrates most meteoroids before they reach the ground, the Moon has little-to-no atmosphere to prevent meteoroids from impacting the lunar surface. Upon impact, the meteoroid's kinetic energy is partitioned into crater excavation, seismic wave production, and the generation of a debris plume. A flash of light associated with the plume is detectable by instruments on Earth. Following the initial observation of a probable Taurid impact flash on the Moon in November 2005,1 the NASA Meteoroid Environment Office (MEO) began a routine monitoring program to observe the Moon for meteoroid impact flashes in early 2006, resulting in the observation of over 330 impacts to date. The main objective of the MEO is to characterize the meteoroid environment for application to spacecraft engineering and operations. The Lunar Impact Monitoring Program provides information about the meteoroid flux in near-Earth space in a size range-tens of grams to a few kilograms-difficult to measure with statistical significance by other means. A bright impact flash detected by the program in March 2013 brought into focus the importance of determining the impact flash location. Prior to this time, the location was estimated to the nearest half-degree by visually comparing the impact imagery to maps of the Moon. Better accuracy was not needed because meteoroid flux calculations did not require high-accuracy impact locations. But such a bright event was thought to have produced a fresh crater detectable from lunar orbit by the NASA spacecraft Lunar Reconnaissance Orbiter (LRO). The idea of linking the observation of an impact flash with its crater was an appealing one, as it would validate NASA photometric calculations and crater scaling laws developed from hypervelocity gun testing. This idea was

Simple flash evaporator for making thin films of compounds

Energy Technology Data Exchange (ETDEWEB)

Hemanadhan, M.; Bapanayya, Ch.; Agarwal, S. C. [Department of Physics, Indian Institute of Technology, Kanpur 208016 (India)

2010-07-15

A simple and compact arrangement for flash evaporation is described. It uses a cell phone vibrator for powder dispensing that can be incorporated into a vacuum deposition chamber without any major alterations. The performance of the flash evaporation system is checked by making thin films of the optical memory chalcogenide glass Ge{sub 2}Sb{sub 2}Te{sub 5} (GST). Energy dispersive x-ray analysis shows that the flash evaporation preserves the stoichiometry in thin films.

A comparison between characteristics of atmospheric-pressure plasma jets sustained by nanosecond- and microsecond-pulse generators in helium

International Nuclear Information System (INIS)

Zhang, Cheng; Shao, Tao; Wang, Ruixue; Yan, Ping; Zhou, Zhongsheng; Zhou, Yixiao

2014-01-01

Power source is an important parameter that can affect the characteristics of atmospheric-pressure plasma jets (APPJs), because it can play a key role on the discharge characteristics and ionization process of APPJs. In this paper, the characteristics of helium APPJs sustained by both nanosecond-pulse and microsecond-pulse generators are compared from the aspects of plume length, discharge current, consumption power, energy, and optical emission spectrum. Experimental results showed that the pulsed APPJ was initiated near the high-voltage electrode with a small curvature radius, and then the stable helium APPJ could be observed when the applied voltage increased. Moreover, the discharge current of the nanosecond-pulse APPJ was larger than that of the microsecond-pulse APPJ. Furthermore, although the nanosecond-pulse generator consumed less energy than the microsecond-pulse generator, longer plume length, larger instantaneous power per pulse and stronger spectral line intensity could be obtained in the nanosecond-pulse excitation case. In addition, some discussion indicated that the rise time of the applied voltage could play a prominent role on the generation of APPJs

In vitro and in vivo anti-Staphylococcus aureus activities of a new disinfection system utilizing photolysis of hydrogen peroxide.

Science.gov (United States)

Hayashi, Eisei; Mokudai, Takayuki; Yamada, Yasutomo; Nakamura, Keisuke; Kanno, Taro; Sasaki, Keiichi; Niwano, Yoshimi

2012-08-01

The present study aimed to evaluate in vitro and in vivo antibacterial activity of hydroxyl radical generation system by photolysis of H(2)O(2), which is a new disinfection system for the treatment of oral infection diseases such as periodontitis developed in our laboratory. Firstly, generation of the hydroxyl radical by the photolysis of H(2)O(2) in which 1 mol l(-1) H(2)O(2) was irradiated with a dual wavelength-light emitting diode (LED) at wavelengths of 400 and 465 nm was confirmed by applying an electron spin resonance-spin trapping technique. Secondly, the bactericidal effect of the system was examined under a similar condition in which Staphylococcus aureus suspended in 1 mol l(-1) H(2)O(2) was irradiated with LED light, resulting in substantial reduction of the colony forming unit (CFU) of the bacteria within a short time as 2 min. Finally, in vivo antibacterial effect of the photolysis of H(2)O(2) on a rat model of S. aureus infection was evaluated by a culture study. Since a significant reduction of recovered CFU of S. aureus was obtained, it is expected that in vitro antibacterial effect attributable to hydroxyl radicals generated by photolysis of H(2)O(2) could be well reflected in in vivo superficial bacterial infection. Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Reaction kinetics and mechanisms of organosilicon fungicide flusilazole with sulfate and hydroxyl radicals.

Science.gov (United States)

Mercado, D Fabio; Bracco, Larisa L B; Arques, Antonio; Gonzalez, Mónica C; Caregnato, Paula

2018-01-01

Flusilazole is an organosilane fungicide used for treatments in agriculture and horticulture for control of diseases. The reaction kinetics and mechanism of flusilazole with sulfate and hydroxyl radicals were studied. The rate constant of the radicals with the fungicide were determined by laser flash photolysis of peroxodisulfate and hydrogen peroxide. The results were 2.0 × 10 9 s -1 M -1 for the reaction of the fungicide with HO and 4.6 × 10 8  s -1  M -1 for the same reaction with SO 4 - radicals. The absorption spectra of organic intermediates detected by laser flash photolysis of S 2 O 8 2- with flusilazole, were identified as α-aminoalkyl and siloxyl radicals and agree very well with those estimated employing the time-dependent density functional theory with explicit account for bulk solvent effects. In the continuous photolysis experiments, performed by photo-Fenton reaction of the fungicide, the main degradation products were: (bis(4-fluorophenyl)-hydroxy-methylsilane) and the non-toxic silicic acid, diethyl bis(trimethylsilyl) ester, in ten and twenty minutes of reaction, respectively. Copyright © 2017. Published by Elsevier Ltd.

Comparison of two picosecond lasers to a nanosecond laser for treating tattoos: a prospective randomized study on 49 patients.

Science.gov (United States)

Lorgeou, A; Perrillat, Y; Gral, N; Lagrange, S; Lacour, J-P; Passeron, T

2018-02-01

Q-switched nanosecond lasers demonstrated their efficacy in treating most types of tattoos, but complete disappearance is not always achieved even after performing numerous laser sessions. Picosecond lasers are supposed to be more efficient in clearing tattoos than nanosecond lasers, but prospective comparative data remain limited. To compare on different types of tattoos the efficacy of a nanosecond laser with two types of picosecond lasers. We conducted a prospective randomized study performed from December 2014 to June 2016 on adult patients with all types of tattoos. The tattoos were divided into two halves of equal size. After randomization, half of the tattoo was treated with a picosecond laser and the other half with a nanosecond laser. The evaluation was performed on standardized pictures performed before treatment and 2 months after the last session, by two physicians, not involved in the treatment, blinded on the type of treatments received. The main end point was a clearance above 75% of the tattoos. A total of 49 patients were included. Professional tattoos represented 85.7%, permanent make-up 8.2% and non-professional tattoo 6.1%. The majority were black or blue and 10.2% were polychromatic. No patient was lost during follow-up. A reduction of 75% or more of the colour intensity was obtained for 33% of the tattoos treated with the picosecond lasers compared to 14% with the nanosecond laser (P = 0.008). An improvement superior to 75% was obtained in 34% monochromic black or blue tattoos with the picosecond lasers compared to 9% for the nanosecond laser. Only one of the five polychromic tattoos achieved more than 75% of improvement with the two types of laser. Our results show a statistically significant superiority of the picosecond lasers compared to the nanosecond laser for tattoo clearance. However, they do not show better efficacy for polychromic tattoos and the difference in terms of side-effects was also minimal with a tendency of picosecond

Mechanisms of nucleation in flashing flows

International Nuclear Information System (INIS)

Yan, F.; Giot, M.

1989-01-01

The mechanisms of nucleation have been analysed. Starting from the assumption that the activation of micro-cavities in the wall surfaces is the most probable nucleation mechanism in practical flashing system, the authors study in detail the nucleation in a micro-cavity. A three step nucleation criterion is proposed, namely: trapping cavity, activable cavity and active cavity. Then, a new nucleation model is presented. The output of the model is the prediction of the bubble departure frequency versus the thermodynamic state of the liquid and the geometry of the cavity. The model can also predict the nucleation site density if the nature of the wall and the surface roughness are know. The prediction have been successfully compared with some preliminary experimental results. By combining the present model with Jones'theory, the flashing inception is correctly predicted. The use of this nucleation model for the complete modelling of a flashing non-equilibrium flow is in progress

Flashing of high-pressure saturated water into the pool water

International Nuclear Information System (INIS)

Takamasa, Tomoji; Kondo, Koichi; Aya, Izuo.

1997-01-01

This paper presents an experimental study on a saturated high-pressure water discharging into a water pool. The purpose of the experiment is to clarify the phenomena that occur by a blow-down of the water from the pressure vessel into the water-filled containment in the case of a wall-crack accident or a LOCA in a passive safety reactor. The results show that a flashing oscillation (FO) occurs when the water discharges into the pool, under specified experimental conditions. The range of the flashing location oscillates between a point very close to and some distance away from the vent hole. The pressures in the vent tube and water pool constantly fluctuate due to the flashing oscillation. The pressure oscillation and alternating flashing location might be caused by the balancing action between the supply of saturated water, flashing at the control volume and steam condensation on the steam-water interface. The frequencies of FO, or frequencies of pressure oscillation and alternating flashing location, increased as water subcooling increased, and as discharging pressure and vent hole diameter decreased. A linear analysis was conducted using a spherical flashing bubble model in which the motion of bubble is controlled by steam condensation. The effects of these parameters on the period of FO in the experiments can be predicted well by the analysis. (author)

Antimicrobial activity of hydroxyl radicals generated by hydrogen peroxide photolysis against Streptococcus mutans biofilm.

Science.gov (United States)

Nakamura, Keisuke; Shirato, Midori; Kanno, Taro; Örtengren, Ulf; Lingström, Peter; Niwano, Yoshimi

2016-10-01

Prevention of dental caries with maximum conservation of intact tooth substance remains a challenge in dentistry. The present study aimed to evaluate the antimicrobial effect of H2O2 photolysis on Streptococcus mutans biofilm, which may be a novel antimicrobial chemotherapy for treating caries. S. mutans biofilm was grown on disk-shaped hydroxyapatite specimens. After 1-24 h of incubation, growth was assessed by confocal laser scanning microscopy and viable bacterial counting. Resistance to antibiotics (amoxicillin and erythromycin) was evaluated by comparing bactericidal effects on the biofilm with those on planktonic bacteria. To evaluate the effect of the antimicrobial technique, the biofilm was immersed in 3% H2O2 and was irradiated with an LED at 365 nm for 1 min. Viable bacterial counts in the biofilm were determined by colony counting. The thickness and surface coverage of S. mutans biofilm increased with time, whereas viable bacterial counts plateaued after 6 h. When 12- and 24-h-old biofilms were treated with the minimum concentration of antibiotics that killed viable planktonic bacteria with 3 log reduction, their viable counts were not significantly decreased, suggesting the biofilm acquired antibiotic resistance by increasing its thickness. By contrast, hydroxyl radicals generated by photolysis of 3% H2O2 effectively killed S. mutans in 24-h-old biofilm, with greater than 5 log reduction. The technique based on H2O2 photolysis is a potentially powerful adjunctive antimicrobial chemotherapy for caries treatment. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

Implikasi Multimedia Interaktif Berbasis Flash Terhadap Motivasi dan Prestasi Belajar Matematika

Directory of Open Access Journals (Sweden)

Edi Irawan

2017-06-01

Full Text Available [Bahasa]: Penelitian ini bertujuan untuk menguji efektivitas penggunaan multimedia berbasis flash pada mata kuliah statistika ditinjau dari motivasi belajar dan prestasi belajar mahasiswa. Penelitian ini adalah penelitian eksperimen semu dengan desain pretest-posttest nonequivalent group design. Penelitian ini dilaksanakan di STKIP PGRI Pacitan pada tahun 2016. Instrumen yang digunakan adalah tes prestasi belajar dan angket motivasi belajar mahasiswa. Teknik analisis data yang digunakan adalah uji one sample t-test, uji T2 Hotelling’s, dan uji t-Bonferroni. Hasil penelitian menunjukkan bahwa penggunaan multimedia berbasis flash pada mata kuliah statistika lebih efektif daripada pembelajaran menggunakan media powerpoint ditinjau dari motivasi belajar dan prestasi belajar mahasiswa. Prestasi belajar statistika mahasiswa yang menggunakan media flash lebih baik daripada mahasiswa yang menggunakan media powerpoint. Demikian halnya pada aspek motivasi belajar, mahasiswa yang menggunakan flash mengalami peningkatan motivasi yang lebih signifikan daripada mahasiswa yang menggunakan media powerpoint. Kata kunci: Multimedia Flash; Motivasi Belajar; Prestasi Belajar; Statistika [English]: This study aims to test the effectiveness of the use of flash-based multimedia in the course of statistics toward learning motivation and student achievement. This research is a quasi-experimental research with pretest-posttest nonequivalent group design. This research was conducted at STKIP PGRI Pacitan in 2016. The instrument used was the test of student achievement and questionnaire of student's motivation. Data analysis techniques used one sample t-test, T2 Hotelling's test, and t-Bonferroni test. The results showed that the use of flash-based multimedia in the course of statistics is more effective than learning using powerpoint in terms of learning motivation and student achievement. Students’ achievement in statistics using flash media are better than students

A nanosecond high voltage pulse device for accelerator time analytical system

International Nuclear Information System (INIS)

Lou Binqiao; Ding Furong; Xue Zhihua; Wang Xuemei; Shen Dingyu

2002-01-01

A nanosecond high voltage pulse device has been designed. The pulse rise time is 10 ns. The pulse voltage reached 16000 V. This device has been used to accelerator time analytical system, its resolution time is less than 0.8%

Status of flash radiography in the USA today and future possibilities

International Nuclear Information System (INIS)

Bryant, L.E. Jr.

1978-01-01

A listing of presently employed flash x-ray generators is given including low-energy, commercially available systems and high-energy very specialized installations in government laboratories. These flash x-ray sources are compared as to radiographic characteristics. Imaging techniques and materials are surveyed and compared as to their advantages and limitations. A variety of applications of flash radiography are cited including explosive, ballistic, diffraction, crash injury, and fuel injection. Probable near term advances in special techniques are mentioned in cine radiography and film image enhancement. Possible future developments are speculated upon such as flash radiographic applications of computerized axial tomography. The recent recognition of flash radiography at professional society conferences is reviewed

Effect of Soybeans on Hot Flashes in Postmenopausal Women

Directory of Open Access Journals (Sweden)

H Mozaffari-khosravi

2009-10-01

Full Text Available Introduction: Hot flashes are common and discomfortable signs of menopause that present with blazing sweatiness, sense of hotness, tachycardia and agitation. Hot flashes cause disturbances in daily activity and quality of night sleep. In spite of the effect of Hormone Replacement Therapy (HRT on hot flashes, nowadays, there are diverse opinions about HRT and the reason is that it has chronic complications. In addition, the acceptance of HRT by Iranian women is very low. Study of numerous texts has shown that isofliavone present in soybean is a phytoestrogen that could be effective in control of hot flashes. The purpose of the study is to examine the changes in time periods of hot flashes in response to consumption of 74 mg Isoflavone/day present in 60 grams soybeans in menopausal women. Methods: This study was a clinical trial with before and after design that included 31 postmenopausal women. The participants were assessed with respect to daily hot flashes at baseline and after one, two and three months of intervention. Participants consumed daily 60 grams soybeans for 3 months. Blood samples were taken at the start and end of intervention for determining levels of gonadotropins and estradiol. Data was analyzed by SPSS software. Results: There was a decrease in time period of hot flashes from baseline of 5.88±2.61 to 3.45±1.82 after one month, 2.73±1.57 after two months and 2.16±1.48 after three months of consumption of soybeans (P<0.001. There was decrease in levels of FSH, LH & estradiol after 3 months, but this decrease was not significant, except in the case of estradiol. Conclusion: In line with various studies proposing the use of soybeans in the form of concentrate, drink or capsule, this study suggests that consumption of soybeans (60 gr daily as snacks may be a safe and effective method for controlling hot flashes in postmenopausal women..

Numerical Simulation of a Nanosecond-Pulse Discharge for High-Speed Flow Control

Science.gov (United States)

Poggie, Jonathan; Adamovich, Igor

2012-10-01

Numerical calculations were carried out to examine the physics of the operation of a nanosecond-pulse, single dielectric barrier discharge in a configuration with planar symmetry. This simplified configuration was chosen as a vehicle to develop a physics based nanosecond discharge model, including realistic air plasma chemistry and compressible bulk gas flow. First, a reduced plasma kinetic model was developed by carrying out a sensitivity analysis of zero-dimensional plasma computations with an extended chemical kinetic model. Transient, one- dimensional discharge computations were then carried out using the reduced kinetic model, incorporating a drift-diffusion formulation for each species, a self-consistent computation of the electric potential using the Poisson equation, and a mass-averaged gas dynamic formulation for the bulk gas motion. Discharge parameters (temperature, pressure, and input waveform) were selected to be representative of recent experiments on bow shock control with a nanosecond discharge in a Mach 5 cylinder flow. The computational results qualitatively reproduce many of the features observed in the experiments, including the rapid thermalization of the input electrical energy and the consequent formation of a weak shock wave. At breakdown, input electrical energy is rapidly transformed (over roughly 1 ns) into ionization products, dissociation products, and electronically excited particles, with subsequent thermalization over a relatively longer time-scale (roughly 10 μs).

Reaction of hydrogen atoms produced by radiolysis and photolysis in solid phase at 4 and 77 K

International Nuclear Information System (INIS)

Miyazaki, Tetsuo

1991-01-01

The behavior of H atoms in the solid phase has been reviewed with special attention to comparison of H atoms produced by radiolysis with those produced by photolysis. The paper consists of three parts. I -Production of H atoms: (1) the experimental results which indicate H-atom formation in the radiolysis of solid alkane are summarized; (2) ESR saturation behavior of trapped H atoms depends upon the method of H-atom-production, i.e. photolysis or radiolysis, and upon the initial energy of H atoms in the photolysis. II - Diffusion of H atoms: (1) activation energies for thermally-activated diffusion of H atoms are shown; (2) quantum diffusion of H atoms in solid H 2 is explained in terms of repetition of tunneling reaction H 2 + H → H + H 2 . III -Reaction of H atoms: (1) reactions and trapping processes of hot H atoms have been shown in solid methane and argon by use of hot H atoms with specified initial energy; (2) when H atoms are produced by the radiolysis of solvent alkane or by the photolysis of HI in the alkane mixtures at 77 K, the H atoms react very selectively with solute alkane at low concentration. The selective reaction of the H atom has been found in eight matrices; (3) activation energy for a hydrogen-atom-abstraction reaction by thermal H atoms at low temperatures is less than than several kJ mol -1 because of quantum tunneling. The absolute rate constants for H 2 (D 2 , HD) + H(D) tunneling reactions have been determined experimentally in solid hydrogen at 4.2K; (4) theoretical studies for tunneling reactions H 2 (D 2 ,HD) + H(D) at ultralow temperatures were reviewed. The calculated rate constants were compared with the rate constants obtained experimentally. (author)

Substituent effects on the excited states of phenyl-capped phenylene vinylene tetramers

NARCIS (Netherlands)

Candeias, L.P.; Gelinck, G.H.; Piet, J.J.; Piris, J.; Wegewijs, B.; Peeters, E.; Wildeman, J.; Hadziioannou, G.; Müllen, K.

2001-01-01

The singlet and triplet excited states of phenyl-capped tetramers of phenylene vinylene with different alkyl, alkoxy or cyano substituents, were investigated in benzene solution. The lowest singlet states were studied by laser flash-photolysis with time-resolved microwave conductivity and

Flashes and floaters - a practical approach to assessment and management.

Science.gov (United States)

Kahawita, Shyalle; Simon, Sumu; Gilhotra, Jolly

2014-04-01

Flashes and floaters are common ophthalmic issues for which patients may initially present to their general practitioner. It may be a sign of benign, 
age-related changes of the vitreous or more serious retinal detachment. This article provides a guide to the assessment and management of a patient presenting with flashes and floaters. Although most patients presenting with flashes and floaters have benign 
age-related changes, they must be referred to an ophthalmologist to rule out sight-threatening conditions. Key examination features include the nature of the flashes and floaters, whether one or both eyes are affected and changes in visual acuity or visual field.

Atmospheric fate of a series of carbonyl nitrates: photolysis frequencies and OH-oxidation rate constants.

Science.gov (United States)

Suarez-Bertoa, R; Picquet-Varrault, B; Tamas, W; Pangui, E; Doussin, J-F

2012-11-20

Multifunctional organic nitrates are potential NO(x) reservoirs whose atmospheric chemistry is somewhat little known. They could play an important role in the spatial distribution of reactive nitrogen species and consequently in ozone formation and distribution in remote areas. In this work, the rate constants for the reaction with OH radical and the photolysis frequencies of α-nitrooxyacetone, 3-nitrooxy-2-butanone, and 3-methyl-3-nitrooxy-2-butanone have been determined at room temperature at 1000 mbar total pressure of synthetic air. The rate constants for the OH oxidation were measured using the relative rate technique, with methanol as reference compound. The following rate constants were obtained for the reaction with OH: k(OH) = (6.7 ± 2.5) × 10(-13) cm(3) molecule(-1) s(-1) for α-nitrooxyacetone, (10.6 ± 4.1) × 10(-13) cm(3) molecule(-1) s(-1) for 3-nitrooxy-2-butanone, and (2.6 ± 0.9) × 10(-13) cm(3) molecule(-1) s(-1) for 3-methyl-3-nitrooxy-2-butanone. The corresponding photolysis frequencies extrapolated to typical atmospheric conditions for July first at noon at 40° latitude North were (4.8 ± 0.3) × 10(-5) s(-1), (5.7 ± 0.3) × 10(-5) s(-1), and (7.4 ± 0.2) × 10(-5) s(-1), respectively. The data show that photolysis is a major atmospheric sink for these organic nitrates.

A pilot study of magnetic therapy for hot flashes after breast cancer.

Science.gov (United States)

Carpenter, Janet S; Wells, Nancy; Lambert, Beth; Watson, Peggy; Slayton, Tami; Chak, Bapsi; Hepworth, Joseph T; Worthington, W Bradley

2002-04-01

The purpose of this randomized placebo-controlled crossover pilot study was to evaluate the effectiveness and acceptability of magnetic therapy for hot flashes among breast cancer survivors. Participants completed a 24-hour baseline hot-flash monitoring session, wore the magnetic devices or placebo for 3 days, completed an after-treatment hot-flash monitoring session, experienced a 10-day washout period, and then crossed over to the opposite study arm. Magnetic devices and placebos were placed on 6 acupressure sites corresponding to hot-flash relief. Complete data were available from 11 survivors of breast cancer. Results indicated magnetic therapy was no more effective than placebo in decreasing hot-flash severity, and contrary to expectations, placebo was significantly more effective than magnets in decreasing hot-flash frequency, bother, interference with daily activities, and overall quality of life. Implications for clinical practice and future research include the need to explore alternative interventions aimed at alleviating hot flashes in this population.

Electroporation of Mammalian Cells by Nanosecond Electric Field Oscillations and its Inhibition by the Electric Field Reversal

Science.gov (United States)

2015-09-08

Report 3. DATES COVERED (From – To) March 2013 to July 2015 4. TITLE AND SUBTITLE Electroporation of mammalian cells by nanosecond electric field...Prescribed by ANSI Std. Z39.18 1Scientific RepoRts | 5:13818 | DOi: 10.1038/srep13818 www.nature.com/scientificreports Electroporation of mammalian cells...first to demonstrate that mammalian cells can be electroporated by damped sine wave electric stimuli of nanosecond duration. By comparing the

Flash x-radiography for material motion detection

International Nuclear Information System (INIS)

Choate, L.M.; Buckalew, W.H.; Posey, L.D.

1977-01-01

A significant part of the experimental program dealing with the behavior of prototypic LMFBR fuel pin bundles under mild to severe power transients is that of the observation of fuel/cladding/coolant motion. The feasibility of using electron beam flash x-radiography as a diagnostic tool for safety test facilities is presently under evaluation. A summary of the objectives and approach of the flash x-radiography program is presented

Supershort avalanche electron beams and x-ray in high-pressure nanosecond discharges

International Nuclear Information System (INIS)

Tarasenko, V F; Baksht, E H; Kostyrya, I D; Lomaev, M I; Rybka, D V

2008-01-01

The properties of a supershort avalanche electron beam (S AEB) and X-ray radiation produced using a nanosecond volume discharge are examined. An electron beam of the runaway electrons with amplitude of ∼ 50 A has been obtained in air atmospheric pressure. It is reported that S AEB is formed in the angle above 2π sr. Three groups of the runaway electrons are formed in a gas diode under atmospheric air pressure, when nanosecond voltage pulses with amplitude of hundreds of kilovolts are applied. The electron beam has been generated behind a 45 μm thick AlBe foil in SF 6 and Xe under the pressure of 2 arm, and in He under the pressure of about 12 atm. The paper gives the analysis of a generation mechanism of SAEB.

X-ray emission from a nanosecond-pulse discharge in an inhomogeneous electric field at atmospheric pressure

International Nuclear Information System (INIS)

Zhang Cheng; Shao Tao; Ren Chengyan; Zhang Dongdong; Tarasenko, Victor; Kostyrya, Igor D.; Ma Hao; Yan Ping

2012-01-01

This paper describes experimental studies of the dependence of the X-ray intensity on the anode material in nanosecond high-voltage discharges. The discharges were generated by two nanosecond-pulse generators in atmospheric air with a highly inhomogeneous electric field by a tube-plate gap. The output pulse of the first generator (repetitive pulse generator) has a rise time of about 15 ns and a full width at half maximum of 30–40 ns. The output of the second generator (single pulse generator) has a rise time of about 0.3 ns and a full width at half maximum of 1 ns. The electrical characteristics and the X-ray emission of nanosecond-pulse discharge in atmospheric air are studied by the measurement of voltage-current waveforms, discharge images, X-ray count and dose. Our experimental results showed that the anode material rarely affects electrical characteristics, but it can significantly affect the X-ray density. Comparing the density of X-rays, it was shown that the highest x-rays density occurred in the diffuse discharge in repetitive pulse mode, then the spark discharge with a small air gap, and then the corona discharge with a large air gap, in which the X-ray density was the lowest. Therefore, it could be confirmed that the bremsstrahlung at the anode contributes to the X-ray emission from nanosecond-pulse discharges.

Nanosecond laser therapy reverses pathologic and molecular changes in age-related macular degeneration without retinal damage.

Science.gov (United States)

Jobling, A I; Guymer, R H; Vessey, K A; Greferath, U; Mills, S A; Brassington, K H; Luu, C D; Aung, K Z; Trogrlic, L; Plunkett, M; Fletcher, E L

2015-02-01

Age-related macular degeneration (AMD) is a leading cause of vision loss, characterized by drusen deposits and thickened Bruch's membrane (BM). This study details the capacity of nanosecond laser treatment to reduce drusen and thin BM while maintaining retinal structure. Fifty patients with AMD had a single nanosecond laser treatment session and after 2 yr, change in drusen area was compared with an untreated cohort of patients. The retinal effect of the laser was determined in human and mouse eyes using immunohistochemistry and compared with untreated eyes. In a mouse with thickened BM (ApoEnull), the effect of laser treatment was quantified using electron microscopy and quantitative PCR. In patients with AMD, nanosecond laser treatment reduced drusen load at 2 yr. Retinal structure was not compromised in human and mouse retina after laser treatment, with only a discrete retinal pigment epithelium (RPE) injury, and limited mononuclear cell response observed. BM was thinned in the ApoEnull mouse 3 mo after treatment (ApoEnull treated 683 ± 38 nm, ApoEnull untreated 890 ± 60 nm, C57Bl6J 606 ± 43 nm), with the expression of matrix metalloproteinase-2 and -3 increased (>260%). Nanosecond laser resolved drusen independent of retinal damage and improved BM structure, suggesting this treatment has the potential to reduce AMD progression. © FASEB.

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

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

Transients observed in the low temperature photolysis of alkyl radicals and divalent sulfur substrates

International Nuclear Information System (INIS)

Adam, F.C.

1976-01-01

The 253.7 nm photolysis of the isometric butyl radicals is described. These radicals are produced by electron capture during the γ-radiolysis of the corresponding butyl chlorides diluted in a rigid glass of 3-methylpentane-d14 at 77K. Thus t-butyl gives an equilibrium mixture of i-butyl and methyl radicals. Solvent radicals, M, are also produced and these obscure the former species in 3-MP-h14. Likewise sec-butyl radicals give rise to the ethyl, n-butyl, methyl and small amounts of the i-butyl radicals. Solvent radicals also rearrange and degrade in the photolytic beam, and the mechanism by which these processes occur is discussed. The procedure has also been used to study the formation and photolability of the alkyl thinyl and perthyl radicals occuring in the photolysis of RSH, RSR and RSSR. The thinyl radical is found to be unstable and gives the alkyl radical and atomic sulfur while the perthiyl radical is stable to radiation > 240 nm. (author)

PNG-300 a nanosecond pulsed neutron generator

International Nuclear Information System (INIS)

Sztaricskai, T.; Vasvary, L.; Petoe, G.C.; Devkin, B.V.

1985-01-01

The design and operation of a nanosecond-pulse neutron generator is reported. It was constructed for the measurement of prompt neutron and gamma radiation in experimental studies of fast neutron reactions by time of flight techniques. The acceleration voltage is 300 kV and the total resolution of the generator-neutron spectrometer system is 2 ns. The ion-optical system, the vacuum system and the control of the neutron generator is described in detail. The equipment was used for prompt neutron and gamma radiation induced in construction materials. (R.P.)

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 ...

Current-Voltage Characteristic of Nanosecond - Duration Relativistic Electron Beam

Science.gov (United States)

Andreev, Andrey

2005-10-01

The pulsed electron-beam accelerator SINUS-6 was used to measure current-voltage characteristic of nanosecond-duration thin annular relativistic electron beam accelerated in vacuum along axis of a smooth uniform metal tube immersed into strong axial magnetic field. Results of these measurements as well as results of computer simulations performed using 3D MAGIC code show that the electron-beam current dependence on the accelerating voltage at the front of the nanosecond-duration pulse is different from the analogical dependence at the flat part of the pulse. In the steady-state (flat) part of the pulse), the measured electron-beam current is close to Fedosov current [1], which is governed by the conservation law of an electron moment flow for any constant voltage. In the non steady-state part (front) of the pulse, the electron-beam current is higher that the appropriate, for a giving voltage, steady-state (Fedosov) current. [1] A. I. Fedosov, E. A. Litvinov, S. Ya. Belomytsev, and S. P. Bugaev, ``Characteristics of electron beam formed in diodes with magnetic insulation,'' Soviet Physics Journal (A translation of Izvestiya VUZ. Fizika), vol. 20, no. 10, October 1977 (April 20, 1978), pp.1367-1368.

PENGEMBANGAN MEDIA FLASH BERBASIS PEMBELAJARAN INKUIRI UNTUK MENINGKATKAN HASIL BELAJAR SISWA

Directory of Open Access Journals (Sweden)

Indah Triana Aprillia

2016-01-01

Full Text Available Penelitian ini merupakan penelitian Research and Development (R&D. Tahapan rancangan pengembangan media flash ini menggunakan langkah prosedural oleh Borg and Gall. Tujuan penelitian ini adalah untuk mengetahui keefektifan pada ranah kognitif, afektif dan psikomotorik dalam penggunaan media flash berbasis pembelajaran inkuiri. Pengumpulan data pada penelitian ini menggunakan metode observasi, tes, angket dan dokumentasi. Data hasil penelitian dianalisis menggunakan metode analisis deskriptif kuantitatif. Produk pengembangan dinyatakan valid dan layak apabila telah memenuhi kriteria baik atau sangat baik dari validator. Produk pengembangan teruji untuk meningkatkan hasil belajar siswa yaitu diuji berdasarkan penggunaan media flash pada proses pembelajaran. Hasil pengembangan produk media flash berbasis pembelajaran inkuiri dinyatakan valid dengan kategori baik dan layak diterapkan berdasarkan uji kelayakan oleh ahli media dan ahli materi dengan skor rata-rata ahli media 73.5 dan ahli materi 37. Media flash dinyatakan efektif karena 36 siswa mencapai nilai KKM pada hasil tes, dengan nilai n-gain 0,71 dan pada aspek afektif dan psikomotorik termasuk dalam kategori baik, serta mendapat respon positif dari penggunanya dilihat dari angket tanggapan siswa, sehingga media flash efektif meningkatkan hasil belajar siswa. The research include in Research and Development (R&D. This step of flash media development uses procedural step by Borg and Gall. The purpose of this research is to know the effectiveness in the cognitive, afective, and psychomotoric domain in using flash media based on inquiry learning. Data accumulation in this research uses observation, test, questionaire and documentation methods. The result data of this research is analyzed by using quantitative descriptive analysis method. Development product is called valid and proper if it has fullfilled good or very good criteria from the validator. The development product proved to improve the

High-voltage nanosecond Marx generator with quasi-rectangular pulses

International Nuclear Information System (INIS)

Bulan, V.V.; Grabovskij, E.V.; Gribov, A.N.; Luzhnov, V.G.

1999-01-01

The automated high-voltage nanosecond generator, forming single pulses of any polarity on the load of 17 Ohm with polarity voltage from 100 up to 300 kV at the semiheight of 80 ns and the front of 7 ns is described. The generator is assembled on the basis of low-inductive capacitors, which by discharge form the pulse, close by form to rectangular one [ru

Nanosecond-level time synchronization of AERA using a beacon reference transmitter and commercial airplanes

Science.gov (United States)

Huege, Tim

2017-03-01

Radio detection of cosmic-ray air showers requires time synchronization of detectors on a nanosecond level, especially for advanced reconstruction algorithms based on the wavefront curvature and for interferometric analysis approaches. At the Auger Engineering Radio Array, the distributed, autonomous detector stations are time-synchronized via the Global Positioning System which, however, does not provide sufficient timing accuracy. We thus employ a dedicated beacon reference transmitter to correct for eventby-event clock drifts in our offline data analysis. In an independent cross-check of this "beacon correction" using radio pulses emitted by commercial airplanes, we have shown that the combined timing accuracy of the two methods is better than 2 nanoseconds.

Spectral measurements of muzzle flash with multispectral and hyperspectral sensor

Science.gov (United States)

Kastek, M.; Dulski, R.; Trzaskawka, P.; Piątkowski, T.; Polakowski, H.

2011-08-01

The paper presents some practical aspects of the measurements of muzzle flash signatures. Selected signatures of sniper shot in typical scenarios has been presented. Signatures registered during all phases of muzzle flash were analyzed. High precision laboratory measurements were made in a special ballistic laboratory and as a result several flash patterns were registered. The field measurements of a muzzle flash were also performed. During the tests several infrared cameras were used, including the measurement class devices with high accuracy and frame rates. The registrations were made in NWIR, SWIR and LWIR spectral bands simultaneously. An ultra fast visual camera was also used for visible spectra registration. Some typical infrared shot signatures were presented. Beside the cameras, the LWIR imaging spectroradiometer HyperCam was also used during the laboratory experiments and the field tests. The signatures collected by the HyperCam device were useful for the determination of spectral characteristics of the muzzle flash, whereas the analysis of thermal images registered during the tests provided the data on temperature distribution in the flash area. As a result of the measurement session the signatures of several types handguns, machine guns and sniper rifles were obtained which will be used in the development of passive infrared systems for sniper detection.

A Conceptual Flash Flood Early Warning System for Africa, Based on Terrestrial Microwave Links and Flash Flood Guidance

Directory of Open Access Journals (Sweden)

Joost C. B. Hoedjes

2014-04-01

Full Text Available A conceptual flash flood early warning system for developing countries is described. The system uses rainfall intensity data from terrestrial microwave communication links and the geostationary Meteosat Second Generation satellite, i.e., two systems that are already in place and operational. Flash flood early warnings are based on a combination of the Flash Flood Guidance method and a hydrological model. The system will be maintained and operated through a public-private partnership, which includes a mobile telephone operator, a national meteorological service and an emergency relief service. The mobile telephone operator acts as both the supplier of raw input data and the disseminator of early warnings. The early warning system could significantly reduce the number of fatalities due to flash floods, improve the efficiency of disaster risk reduction efforts and play an important role in strengthening the resilience to climate change of developing countries in Africa. This paper describes the system that is currently being developed for Kenya.

Picosecond dynamics of conformation changes in malachite green dye produced by photoionization of malachite green leucocyanide

Energy Technology Data Exchange (ETDEWEB)

Cremers, D A; Cremers, T L

1983-01-07

The appearance of malachite green dye absorption following photoionization of malachite green leucocyanide has been examined using picosecond flash photolysis. The rate of absorption increase depends upon solvent viscosity and exhibits a two-step behavior in viscous glycerol solutions. 21 references, 4 figures.

Flash-Point prediction for binary partially miscible aqueous-organic mixtures

OpenAIRE

Liaw, Horng-Jang; Chen, Chien Tsun; Gerbaud, Vincent

2008-01-01

Flash point is the most important variable used to characterize fire and explosion hazard of liquids. Herein, partially miscible mixtures are presented within the context of liquid-liquid extraction processes and heterogeneous distillation processes. This paper describes development of a model for predicting the flash point of binary partially miscible mixtures of aqueous-organic system. To confirm the predictive efficiency of the derived flash points, the model was verified by comparing the ...

Mutational analysis of FLASH and PTPN13 genes in colorectal carcinomas.

Science.gov (United States)

Jeong, Eun Goo; Lee, Sung Hak; Yoo, Nam Jin; Lee, Sug Hyung

2008-01-01

The Fas-Fas ligand system is considered a major pathway for induction of apoptosis in cells and tissues. FLASH was identified as a pro-apoptotic protein that transmits apoptosis signal during Fas-mediated apoptosis. PTPN13 interacts with Fas and functions as both suppressor and inducer of Fas-mediated apoptosis. There are polyadenine tracts in both FLASH (A8 and A9 in exon 8) and PTPN13 (A8 in exon 7) genes that could be frameshift mutation targets in colorectal carcinomas. Because genes encoding proteins in Fas-mediated apoptosis frequently harbor somatic mutations in cancers, we explored the possibility as to whether mutations of FLASH and PTPN13 are a feature of colorectal carcinomas. We analysed human FLASH in exon 8 and PTPN13 in exon 7 for the detection of somatic mutations in 103 colorectal carcinomas by a polymerase chain reaction (PCR)- based single-strand conformation polymorphism (SSCP). We detected two mutations in FLASH gene, but none in PTPN13 gene. However, the two mutations were not frameshift (deletion or insertion) mutations in the polyadenine tracts of FLASH. The two mutations consisted of a deletion mutation (c.3734-3737delAGAA) and a missense mutation (c.3703A>C). These data indicate that frameshift mutation in the polyadenine tracts in both FLASH and PTPN13 genes is rare in colorectal carcinomas. Also, the data suggest that both FLASH and PTPN13 mutations in the polyadenine tracts may not have a crucial role in the pathogenesis of colorectal carcinomas.

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

Radial Distribution of the Nanosecond Dielectric Barrier Discharge Current in Atmospheric-Pressure Air

Science.gov (United States)

Malashin, M. V.; Moshkunov, S. I.; Khomich, V. Yu.; Shershunova, E. A.

2018-01-01

Experimental results on the radial distribution of the nanosecond dielectric barrier discharge (DBD) current in flat millimeter air gaps under atmospheric pressure and natural humidity of 40-60% at a voltage rise rate at the electrodes of 250 V/ns are presented. The time delay of the appearance of discharge currents was observed to increase from the center to the periphery of the air gap at discharge gap heights above 3 mm, which correlated with the appearance of constricted channels against the background of the volume DBD plasma. Based on the criterion of the avalanche-streamer transition, it is found out that the development of a nanosecond DBD in air gaps of 1-3 mm occurs by the streamer mechanism.

Nanosecond laser pulse stimulation of spiral ganglion neurons and model cells.

Science.gov (United States)

Rettenmaier, Alexander; Lenarz, Thomas; Reuter, Günter

2014-04-01

Optical stimulation of the inner ear has recently attracted attention, suggesting a higher frequency resolution compared to electrical cochlear implants due to its high spatial stimulation selectivity. Although the feasibility of the effect is shown in multiple in vivo experiments, the stimulation mechanism remains open to discussion. Here we investigate in single-cell measurements the reaction of spiral ganglion neurons and model cells to irradiation with a nanosecond-pulsed laser beam over a broad wavelength range from 420 nm up to 1950 nm using the patch clamp technique. Cell reactions were wavelength- and pulse-energy-dependent but too small to elicit action potentials in the investigated spiral ganglion neurons. As the applied radiant exposure was much higher than the reported threshold for in vivo experiments in the same laser regime, we conclude that in a stimulation paradigm with nanosecond-pulses, direct neuronal stimulation is not the main cause of optical cochlea stimulation.

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

Energy Technology Data Exchange (ETDEWEB)

Raftery, Alicia Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

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 UO_2.00 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

Application of adobe flash media to optimize jigsaw learning model on geometry material

Science.gov (United States)

Imam, P.; Imam, S.; Ikrar, P.

2018-05-01

This study aims to determine and describe the effectiveness of the application of adobe flash media for jigsaw learning model on geometry material. In this study, the modified jigsaw learning with adobe flash media is called jigsaw-flash model. This research was conducted in Surakarta. The research method used is mix method research with exploratory sequential strategy. The results of this study indicate that students feel more comfortable and interested in studying geometry material taught by jigsaw-flash model. In addition, students taught using the jigsaw-flash model are more active and motivated than the students who were taught using ordinary jigsaw models. This shows that the use of the jigsaw-flash model can increase student participation and motivation. It can be concluded that the adobe flash media can be used as a solution to reduce the level of student abstraction in learning mathematics.

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.

Characteristics of Laser Flash Technique for Thermal Diffusivity Measurement

Energy Technology Data Exchange (ETDEWEB)

Park, D. G.; Kim, H. M.; Hong, G. P

2008-08-15

In relation to selection of thermal conductivity measurement technology, various thermal conductivity measurement technique are investigated for characteristics of each technique and it's measurable range. For the related laser flash techniques, various technical characteristics are reviewed and discussed. Especially, Parker adiabatic model are reviewed because of importance for basic theory of the thermal diffusivity determination. Finite pulse time effect, heat loss effect and non-uniform heating effect, which are main technical factors for laser flash technique, are considered. Finally, characteristics of constituent elements for laser flash measurement system are reviewed and investigated in detail.

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?'

Spurious dispersion effects at FLASH

International Nuclear Information System (INIS)

Prat, Eduard

2009-07-01

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.)

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.)

Flash radiographic technique applied to fuel injector sprays

International Nuclear Information System (INIS)

Vantine, H.C.

1977-01-01

A flash radiographic technique, using 50 ns exposure times, was used to study the pattern and density distribution of a fuel injector spray. The experimental apparatus and method are described. An 85 kVp flash x-ray generator, designed and fabricated at the Lawrence Livermore Laboratory, is utilized. Radiographic images, recorded on standard x-ray films, are digitized and computer processed

Wide Bandgap Semiconductor Detector Optimization for Flash X-Ray Measurements

Energy Technology Data Exchange (ETDEWEB)

Roecker, Caleb Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schirato, Richard C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-11-17

Charge trapping, resulting in a decreased and spatially dependent electric field, has long been a concern for wide bandgap semiconductor detectors. While significant work has been performed to characterize this degradation at varying temperatures and radiation environments, this work concentrates upon examining the event-to-event response in a flash X-ray environment. The following work investigates if charge trapping is a problem for CZT detectors, with particular emphasis on flash X-ray radiation fields at cold temperatures. Results are compared to a non-flash radiation field, using an Am-241 alpha source and similar temperature transitions. Our ability to determine if a response change occurred was hampered by the repeatability of our flash X-ray systems; a small response change was observed with the Am-241 source. Due to contrast of these results, we are in the process of revisiting the Am-241 measurements in the presence of a high radiation environment. If the response change is more pronounced in the high radiation environment, a similar test will be performed in the flash X-ray environment.

Flash trajectory imaging of target 3D motion

Science.gov (United States)

Wang, Xinwei; Zhou, Yan; Fan, Songtao; He, Jun; Liu, Yuliang

2011-03-01

We present a flash trajectory imaging technique which can directly obtain target trajectory and realize non-contact measurement of motion parameters by range-gated imaging and time delay integration. Range-gated imaging gives the range of targets and realizes silhouette detection which can directly extract targets from complex background and decrease the complexity of moving target image processing. Time delay integration increases information of one single frame of image so that one can directly gain the moving trajectory. In this paper, we have studied the algorithm about flash trajectory imaging and performed initial experiments which successfully obtained the trajectory of a falling badminton. Our research demonstrates that flash trajectory imaging is an effective approach to imaging target trajectory and can give motion parameters of moving targets.

4-Pyridylnitrene and 2-pyrazinylcarbene

Science.gov (United States)

Reisinger, Ales; Kvaskoff, David

2013-01-01

Summary Both flash vacuum thermolysis (FVT) and matrix photolysis generate 2-diazomethylpyrazine (22) from 1,2,3-triazolo[1,5-a]pyrazine (24). FVT of 4-azidopyridine (18) as well as of 24 or 2-(5-tetrazolyl)pyrazine (23) affords the products expected from the nitrene, i.e., 4,4’-azopyridine and 2- and 3-cyanopyrroles. Matrix photolyses of both 18 and 24 result in ring expansion of 4-pyridylnitrene/2-pyrazinylcarbene to 1,5-diazacyclohepta-1,2,4,6-tetraene (20). Further photolysis causes ring opening to the ketenimine 27. PMID:23766787

Flash-induced fading: Dependence on colour and shape similarity

NARCIS (Netherlands)

Vergeer, M.L.T.; Lier, R.J. van

2005-01-01

We investigated the effects of perceptual grouping by colour and shape similarity on flash-induced perceptual fading. This flash-induced fading effect (Kanai et al, 2003 Journal of Cognitive Neuroscience 15 664 - 672) is considered as a time-locked variant of the Troxler effect. In the original

Digital Device Architecture and the Safe Use of Flash Devices in Munitions

Science.gov (United States)

Katz, Richard B.; 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. Digital devices of interest to designers include flash-based microcontrollers and field programmable gate arrays (FPGAs). Almost a decade ago, a study was undertaken to determine if flash-based microcontrollers could be safely used in fuzes and, if so, how should such devices be applied. The results were documented in the Technical Manual for the Use of Logic Devices in Safety Features. This paper will first review the Technical Manual and discuss the rationale behind the suggested architectures for microcontrollers and a brief review of the concern about data retention in flash cells. An architectural feature in the microcontroller under study will be discussed and its use will show how to screen for weak or failed cells during manufacture, storage, or immediately prior to use. As was done for microcontrollers a decade ago, architectures for a flash-based FPGA will be discussed, showing how it can be safely used in fuzes. Additionally, architectures for using non-volatile (including flash-based) storage will be discussed for SRAM-based FPGAs.

Review of supershort avalanche electron beam during nanosecond-pulse discharges in some gases

Directory of Open Access Journals (Sweden)

Victor F. Tarasenko

2017-05-01

Full Text Available Supershort avalanche electron beam (SAEB plays an important role in nanosecond-pulse discharges. This paper aims at reviewing experiments results on characteritics of SAEB and its spectra in different gases in nanosecond-pulse discharges. All the joint experiments were carried in the Institute of High Current Electronics of the Russian Academy of Sciences and the Institute of Electrical Engineering of the Chinese Academy of Sciences. In these experiments, the generation of a SAEB in SF6 in an inhomogeneous electric field was studied on three generators with pulse rise times of 0.3, 0.5 and ∼2 ns. Firstly, the comparison of SAEB parameters in SF6 with those obtained in other gases (air, nitrogen, argon, and krypton is introduced. Secondly, the SAEB spectra in SF6 and air at pressures of 10 kPa (75 torr, and 0.1 MPa (750 torr are reviewed and discussed. Finally, 1.5-D theoretical simulation of the supershort pulse of the fast electron beam in a coaxial diode filled with SF6 at atmospheric pressure is described. The simulation was carried out in the framework of hybrid model for discharge and runaway electron kinetics. The above research progress can provide better understanding of the investigation into the mechanism of nanosecond-pulse discharges.

Modeling of plasma chemical processes in the artificial ionized layer in the upper atmosphere by the nanosecond corona discharge

Science.gov (United States)

Vikharev, A. L.; Gorbachev, A. M.; Ivanov, O. A.; Kolisko, A. L.; Litvak, A. G.

1993-08-01

The plasma chemical processes in the corona discharge formed in air by a series of high voltage pulses of nanosecond duration are investigated experimentally. The experimental conditions (reduced electric field, duration and repetition frequency of the pulses, gas pressure in the chamber) modeled the regime of creation of the artificial ionized layer (AIL) in the upper atmosphere by a nanosecond microwave discharge. It was found that in a nanosecond microwave discharge predominantly generation of ozone occurs, and that the production of nitrogen dioxide is not large. The energy expenditures for the generation of one O 3 molecule were about 15 eV. On the basis of the experimental results the prognosis of the efficiency of ozone generation in AIL was made.

Electrosensitization Increases Antitumor Effectiveness of Nanosecond Pulsed Electric Fields In Vivo.

Science.gov (United States)

Muratori, Claudia; Pakhomov, Andrei G; Heller, Loree; Casciola, Maura; Gianulis, Elena; Grigoryev, Sergey; Xiao, Shu; Pakhomova, O N

2017-01-01

Nanosecond pulsed electric fields are emerging as a new modality for tissue and tumor ablation. We previously reported that cells exposed to pulsed electric fields develop hypersensitivity to subsequent pulsed electric field applications. This phenomenon, named electrosensitization, is evoked by splitting the pulsed electric field treatment in fractions (split-dose treatments) and causes in vitro a 2- to 3-fold increase in cytotoxicity. The aim of this study was to show the benefit of split-dose treatments for in vivo tumor ablation by nanosecond pulsed electric field. KLN 205 squamous carcinoma cells were embedded in an agarose gel or grown subcutaneously as tumors in mice. Nanosecond pulsed electric field ablations were produced using a 2-needle probe with a 6.5-mm interelectrode distance. In agarose gel, splitting a pulsed electric field dose of 300, 300-ns pulses (20 Hz, 4.4-6.4 kV) in 2 equal fractions increased cell death up to 3-fold compared to single-train treatments. We then compared the antitumor effectiveness of these treatments in vivo. At 24 hours after treatment, sensitizing tumors by a split-dose pulsed electric field exposure (150 + 150, 300-ns pulses, 20 Hz, 6.4 kV) caused a 4- and 2-fold tumor volume reduction as compared to sham and single-train treatments, respectively. Tumor volume reduction that exceeds 75% was 43% for split-dose-treated animals compared to only 12% for single-dose treatments. The difference between the 2 experimental groups remained statistically significant for at least 1 week after the treatment. The results show that electrosensitization occurs in vivo and can be exploited to assist in vivo cancer ablation.

Studies on laser material processing with nanosecond and sub-nanosecond and picosecond and sub-picosecond pulses

Science.gov (United States)

Zhang, Jie; Tao, Sha; Wang, Brian; Zhao, Jay

2016-03-01

In this paper, laser ablation of widely used metal (Al, Cu. stainless-steel), semiconductor (Si), transparent material (glass, sapphire), ceramic (Al2O3, AlN) and polymer (PI, PMMA) in industry were systematically studied with pulse width from nanosecond (5-100ns), picosecond (6-10ps) to sub-picosecond (0.8-0.95ps). A critical damage zone (CDZ) of up to 100um with ns laser, efficiency were also investigated. This is to explore how to provide industry users the best laser solution for device micro-fabrication with best price. Our studies of cutting and drilling with ns, ps, and sub-ps lasers indicate that it is feasible to achieve user accepted quality and speed with cost-effective and reliable laser by optimizing processing conditions.

Sub-nanosecond lasers for cosmetics and dermatology

Science.gov (United States)

Tarasov, Aleksandr A.; Chu, Hong

2018-02-01

We report about the development of two new subnanosecond solid-state laser models for application in dermatology and cosmetics. One model uses subnanosecond Nd: YAG microchip laser as a master oscillator and includes Nd: YAG double- and single-pass amplifiers. At 10 Hz this laser produces more than 600 mJ pulse energy with duration 500 +/- 5 ps. Another model (under development) is gain-switched Ti: Sapphire laser with short cavity. This laser produces 200 mJ, 560 ps pulses at 790 nm and uses standard Q-Switched Nd: YAG laser with nanosecond pulse duration as a pumping sourse.

Recovery of Flash Memories for Reliable Mobile Storages

Directory of Open Access Journals (Sweden)

Daesung Moon

2010-01-01

Full Text Available As the mobile appliance is applied to many ubiquitous services and the importance of the information stored in it is increased, the security issue to protect the information becomes one of the major concerns. However, most previous researches focused only on the communication security, not the storage security. Especially, a flash memory whose operational characteristics are different from those of HDD is used increasingly as a storage device for the mobile appliance because of its resistance to physical shock and lower power requirement. In this paper, we propose a flash memory management scheme targeted for guaranteeing the data integrity of the mobile storage. By maintaining the old data specified during the recovery window, we can recover the old data when the mobile appliance is attacked. Also, to reduce the storage requirement for the recovery, we restrict the number of versions to be copied, called Degree of Integrity (DoI. Especially, we consider both the reclaim efficiency and the wear leveling which is a unique characteristic of the flash memory. Based on the performance evaluation, we confirm that the proposed scheme can be acceptable to many applications as a flash memory management scheme for improving data integrity.

Parietal disruption alters audiovisual binding in the sound-induced flash illusion.

Science.gov (United States)

Kamke, Marc R; Vieth, Harrison E; Cottrell, David; Mattingley, Jason B

2012-09-01

Selective attention and multisensory integration are fundamental to perception, but little is known about whether, or under what circumstances, these processes interact to shape conscious awareness. Here, we used transcranial magnetic stimulation (TMS) to investigate the causal role of attention-related brain networks in multisensory integration between visual and auditory stimuli in the sound-induced flash illusion. The flash illusion is a widely studied multisensory phenomenon in which a single flash of light is falsely perceived as multiple flashes in the presence of irrelevant sounds. We investigated the hypothesis that extrastriate regions involved in selective attention, specifically within the right parietal cortex, exert an influence on the multisensory integrative processes that cause the flash illusion. We found that disruption of the right angular gyrus, but not of the adjacent supramarginal gyrus or of a sensory control site, enhanced participants' veridical perception of the multisensory events, thereby reducing their susceptibility to the illusion. Our findings suggest that the same parietal networks that normally act to enhance perception of attended events also play a role in the binding of auditory and visual stimuli in the sound-induced flash illusion. Copyright © 2012 Elsevier Inc. All rights reserved.

Electronic Excitations in Fischer-Type Cr and W Aminocarbene Complexes: A Combined ab Initio and Experimental Study

Czech Academy of Sciences Publication Activity Database

Kvapilová, Hana; Hoskovcová, Irena; Kayanuma, M.; Daniel, CH.; Záliš, Stanislav

2013-01-01

Roč. 117, č. 45 (2013), s. 11456-11463 ISSN 1089-5639 R&D Projects: GA MŠk LD11086 Institutional support: RVO:61388955 Keywords : METAL CARBENE COMPLEXES * FLASH-PHOTOLYSIS * BASIS-SETS Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.775, year: 2013

Nanosecond-level time synchronization of AERA using a beacon reference transmitter and commercial airplanes

Directory of Open Access Journals (Sweden)

Huege Tim

2017-01-01

Full Text Available Radio detection of cosmic-ray air showers requires time synchronization of detectors on a nanosecond level, especially for advanced reconstruction algorithms based on the wavefront curvature and for interferometric analysis approaches. At the Auger Engineering Radio Array, the distributed, autonomous detector stations are time-synchronized via the Global Positioning System which, however, does not provide sufficient timing accuracy. We thus employ a dedicated beacon reference transmitter to correct for eventby-event clock drifts in our offline data analysis. In an independent cross-check of this “beacon correction” using radio pulses emitted by commercial airplanes, we have shown that the combined timing accuracy of the two methods is better than 2 nanoseconds.

Wind tunnel experiments on flow separation control of an Unmanned Air Vehicle by nanosecond discharge plasma aerodynamic actuation

International Nuclear Information System (INIS)

Chen Kang; Liang Hua

2016-01-01

Plasma flow control (PFC) is a new kind of active flow control technology, which can improve the aerodynamic performances of aircrafts remarkably. The flow separation control of an unmanned air vehicle (UAV) by nanosecond discharge plasma aerodynamic actuation (NDPAA) is investigated experimentally in this paper. Experimental results show that the applied voltages for both the nanosecond discharge and the millisecond discharge are nearly the same, but the current for nanosecond discharge (30 A) is much bigger than that for millisecond discharge (0.1 A). The flow field induced by the NDPAA is similar to a shock wave upward, and has a maximal velocity of less than 0.5 m/s. Fast heating effect for nanosecond discharge induces shock waves in the quiescent air. The lasting time of the shock waves is about 80 μs and its spread velocity is nearly 380 m/s. By using the NDPAA, the flow separation on the suction side of the UAV can be totally suppressed and the critical stall angle of attack increases from 20° to 27° with a maximal lift coefficient increment of 11.24%. The flow separation can be suppressed when the discharge voltage is larger than the threshold value, and the optimum operation frequency for the NDPAA is the one which makes the Strouhal number equal one. The NDPAA is more effective than the millisecond discharge plasma aerodynamic actuation (MDPAA) in boundary layer flow control. The main mechanism for nanosecond discharge is shock effect. Shock effect is more effective in flow control than momentum effect in high speed flow control. (paper)

Investigations of UV photolysis of PVP-capped silver nanoparticles in the presence and absence of dissolved organic carbon

International Nuclear Information System (INIS)

Poda, Aimee R.; Kennedy, Alan J.; Cuddy, Michael F.; Bednar, Anthony J.

2013-01-01

This study investigated the effect of UV irradiation on the characteristics and toxicity of 50 nm (nominal diameter) polyvinylpyrrolidone-capped silver nanoparticles (AgNPs) in the presence and absence of dissolved organic carbon (DOC). The photolysis resulted in a decrease in average particle size as measured by field flow fractionation interfaced with inductively coupled plasma mass spectrometry. The decrease in size was attributed to the photo-induced oxidation of the PVP and dissolution of metallic silver. Moreover, photolysis of the AgNPs in solutions containing DOC appeared to give rise to small nanoparticles (∼5 nm) formed via reduction of dissolved silver ions. These results were consistent with photolysis of AgNO 3 solutions initially devoid of nanoparticles. Thus, the carbon-containing constituents of DOC serve as reducing agents for Ag + , primarily under conditions of UV irradiation. The standard zooplankton model, Daphnia magna, indicated that the toxicity of nanosilver was significantly reduced when the AgNPs have been exposed to UV light. Observed toxicity was further reduced when AgNPs in DOC-containing solutions were exposed to UV. These results suggest that environmentally relevant conditions such as DOC and UV light are important mitigating factors that mediate the aquatic toxicity of AgNPs.

Search for the radio occulation flash at Jupiter

International Nuclear Information System (INIS)

Martin, J.M.; Tyler, G.L.; Eshleman, V.R.; Wood, G.E.; Lindall, G.F.

1981-01-01

The 'evolute flash' a focusing effect caused by the curvature of a planet's limb, was sought in the radio data taken during the occulation of Voyager 1 by Jupiter, using a modified matched-filter technique. The expected frequency structure of the flash signal is double branched, while the intensity structure is highly localized in time. The search for the signal was carried out over a 6.4 s period. The signal parameters were varied to span the uncertainties introduced by imperfect knowledge of the orbit of the spacecraft and the shape of Jupiter. Several peaks at the 8 standard deviation level were present in the filter output. However, these peaks were separated in time by up to 3.3 s, and none could be identified as the flash. From this negative result a lower bound on the absorption along a ray with periapsis near the 4 bar level in Jupiter's atmosphere can be established at 25 dB. Employing the new Voyager results on the structure of the atmosphere of Jupiter and the mixing ratio of the absorbent ammonia, as well as the improved knowledge of flash characteristics resulting from this study, we estimate that the flash would have been detected if the distance behind the planet where the spacecraft trajectory crossed the evolute were at least 20 Jupiter radii, as compared with a value near 7 in the experiment. For focusing at this greater distance, the atmospheric pressure at the ray periapsis would be between 1.5 and 2 bar

Flash evaporator

OpenAIRE

1997-01-01

A device and method for flash evaporating a reagent includes an evaporation chamber that houses a dome on which evaporation occurs. The dome is solid and of high thermal conductivity and mass, and may be heated to a temperature sufficient to vaporize a specific reagent. The reagent is supplied from an external source to the dome through a nozzle, and may be supplied as a continuous stream, as a shower, and as discrete drops. A carrier gas may be introduced into the evaporation chamber and cre...

Snow nitrate photolysis in polar regions and the mid-latitudes: Impact on boundary layer chemistry and implications for ice core records

Science.gov (United States)

Zatko, Maria C.

The formation and recycling of nitrogen oxides (NOx=NO+NO 2) associated with snow nitrate photolysis has important implications for air quality and the preservation of nitrate in ice core records. This dissertation examines snow nitrate photolysis in polar and mid-latitude regions using field and laboratory based observations combined with snow chemistry column models and a global chemical transport model to explore the impacts of snow nitrate photolysis on boundary layer chemistry and the preservation of nitrate in polar ice cores. Chapter 1 describes how a global chemical transport model is used to calculate the photolysis-driven flux and redistribution of nitrogen across Antarctica, and Chapter 2 presents similar work for Greenland. Snow-sourced NOx is most dependent on the quantum yield for nitrate photolysis as well as the concentration of photolabile nitrate and light-absorbing impurities (e.g., black carbon, dust, organics) in snow. Model-calculated fluxes of snow-sourced NOx are similar in magnitude in Antarctica (0.5--7.8x108 molec cm-2 s -1) and Greenland (0.1--6.4x108 molec cm-2 s-1) because both nitrate and light-absorbing impurity concentrations in snow are higher (by factors of 2 and 10, respectively) in Greenland. Snow nitrate photolysis influences boundary layer chemistry and ice-core nitrate preservation less in Greenland compared to Antarctica largely due to Greenland's proximity to NOx-source regions. Chapter 3 describes how a snow chemistry column model combined with chemistry and optical measurements from the Uintah Basin Winter Ozone Study (UBWOS) 2014 is used to calculate snow-sourced NOx in eastern Utah. Daily-averaged fluxes of snow-sourced NOx (2.9x10 7--1.3x108 molec cm-2 s-1) are similar in magnitude to polar snow-sourced NO x fluxes, but are only minor components of the Uintah Basin boundary layer NOx budget and can be neglected when developing ozone reduction strategies for the region. Chapter 4 presents chemical and optical

Mitochondrial flash as a novel biomarker of mitochondrial respiration in the heart.

Science.gov (United States)

Gong, Guohua; Liu, Xiaoyun; Zhang, Huiliang; Sheu, Shey-Shing; Wang, Wang

2015-10-01

Mitochondrial respiration through electron transport chain (ETC) activity generates ATP and reactive oxygen species in eukaryotic cells. The modulation of mitochondrial respiration in vivo or under physiological conditions remains elusive largely due to the lack of appropriate approach to monitor ETC activity in a real-time manner. Here, we show that ETC-coupled mitochondrial flash is a novel biomarker for monitoring mitochondrial respiration under pathophysiological conditions in cultured adult cardiac myocyte and perfused beating heart. Through real-time confocal imaging, we follow the frequency of a transient bursting fluorescent signal, named mitochondrial flash, from individual mitochondria within intact cells expressing a mitochondrial matrix-targeted probe, mt-cpYFP (mitochondrial-circularly permuted yellow fluorescent protein). This mt-cpYFP recorded mitochondrial flash has been shown to be composed of a major superoxide signal with a minor alkalization signal within the mitochondrial matrix. Through manipulating physiological substrates for mitochondrial respiration, we find a close coupling between flash frequency and the ETC electron flow, as measured by oxygen consumption rate in cardiac myocyte. Stimulating electron flow under physiological conditions increases flash frequency. On the other hand, partially block or slowdown electron flow by inhibiting the F0F1 ATPase, which represents a pathological condition, transiently increases then decreases flash frequency. Limiting electron entrance at complex I by knocking out Ndufs4, an assembling subunit of complex I, suppresses mitochondrial flash activity. These results suggest that mitochondrial electron flow can be monitored by real-time imaging of mitochondrial flash. The mitochondrial flash frequency could be used as a novel biomarker for mitochondrial respiration under physiological and pathological conditions. Copyright © 2015 the American Physiological Society.

Lifetimes and reactivities of some 1,2-didehydroazepines commonly used in photoaffinity labeling experiments in aqueous solutions.

Science.gov (United States)

Rizk, Mary S; Shi, Xiaofeng; Platz, Matthew S

2006-01-17

The reactive 1,2-didehydroazepine (cyclic ketenimine) intermediates produced upon photolysis of phenyl azide, 3-hydroxyphenyl azide, 3-methoxyphenyl azide, and 3-nitrophenyl azide in water and in HEPES buffer were studied by laser flash photolysis techniques with UV-vis detection of the transient intermediates. The lifetimes of the 1,2-didehydroazepines were obtained along with the absolute rate constants of their reactions with typical amino acids, nucleosides, and other simple reagents present in a biochemical milieu. The nitro substituent greatly accelerates the bimolecular reactions of the cyclic ketenimines, and the 3-methoxy group greatly decelerates the absolute reactivity of 1,2-didehydroazepines. The intermediate produced by photolysis of 3-hydroxyphenyl azide is much more reactive than the intermediate produced by photolysis of 3-methoxyphenyl azide. We propose that the hydroxyl-substituted 1,2-didehydoazepines rapidly (ketenimines undergo hydrolysis. Azepinones react more rapidly with nucleophiles than do methoxy-substituted 1,2-didehydroazepines and are the active species present upon the photolysis of 3-hydroxyphenyl azide in aqueous solution.

Photolysis study of octyl p-methoxycinnamate loaded microemulsion by molecular fluorescence and chemometric approach

Science.gov (United States)

Nascimento, Danielle Silva; Insausti, Matías; Band, Beatriz Susana Fernández; Grünhut, Marcos

2018-02-01

Octyl p-methoxycinnamate (OMC) is one of the most widely used sunscreen agents. However, the efficiency of OMC as UV filter over time is affected due to the formation of the cis-isomer which presents a markedly lower extinction coefficient (εcis = 12,600 L mol- 1 cm- 1 at 291 nm) than the original trans-isomer (εtrans = 24,000 L mol- 1 cm- 1 at 310 nm). In this work, a novel carrier for OMC based on an oil-in-water microemulsion is proposed in order to improve the photostability of this sunscreen. The formulation was composed of 29.2% (w/w) of a 3:1 mixture of ethanol (co-surfactant) and decaethylene glycol mono-dodecyl ether (surfactant), 1.5% (w/w) of oleic acid (oil phase) and 69.2% (w/w) of water. This microemulsion was prepared in a simple way, under moderate stirring at 25 °C and using acceptable, biocompatible and accessible materials for topical use. OMC was incorporated in the vehicle at a final concentration of 5.0% (w/w), taking into account the maximum permitted levels established by international norms. Then, a photolysis study of the loaded formulation was performed using a continuous flow system. The direct photolysis was monitored over time by molecular fluorescence. The recorded spectra data between 370 y 490 nm were analyzed by multivariate curve resolution-alternating least squares algorithm. The kinetic rate constants corresponding to the photolysis of the trans-OMC were calculated from the concentration profiles, resulting in 0.0049 s- 1 for the trans-OMC loaded microemulsion and 0.0131 s- 1 for the trans-OMC in aqueous media. These results demonstrate a higher photostability of the trans-OMC when loaded in the proposed vehicle with respect to the free trans-OMC in aqueous media.

Flashing subdiffusive ratchets in viscoelastic media

International Nuclear Information System (INIS)

Kharchenko, Vasyl; Goychuk, Igor

2012-01-01

We study subdiffusive ratchet transport in periodically and randomly flashing potentials. A central Brownian particle is elastically coupled to the surrounding auxiliary Brownian quasi-particles, which account for the influence of the viscoelastic environment. Similar to standard dynamical modeling of Brownian motion, the external force influences only the motion of the central particle, not affecting directly the environmental degrees of freedom. Just a handful of auxiliary Brownian particles suffices to model subdiffusion over many temporal decades. Time modulation of the potential violates the symmetry of thermal detailed balance and induces an anomalous subdiffusive current which exhibits a remarkably small dispersion at low temperatures, as well as a number of other surprising features such as saturation at low temperatures, and multiple inversions of the transport direction upon a change of the driving frequency in the non-adiabatic regime. It is shown that the subdiffusive current is finite at zero temperature for random flashing and can be finite for periodic flashing for a certain frequency window. Our study generalizes classical Brownian motors towards operating in sticky viscoelastic environments such as the cytosol of biological cells or dense polymer solutions. (paper)

Performance of the Fitch generator in a nanosecond electron accelerator

International Nuclear Information System (INIS)

Chernyj, V.V.

1976-01-01

The operation of the Fitch generator in the nanosecond electron accelerator is discussed. The operating principle of the generator is based on the inversion of the voltage at the storage capacitances. Only one discharger is employed in the discharge circuit of the generator which provides for decreasing the generator impedance to 24 Ohms. The maximum accelerating voltage equals 0.6 MV

Cardiac and vascular imaging with snapshot FLASH MR imaging

International Nuclear Information System (INIS)

Matthaei, D.; Haase, A.; Norris, D.; Leibfritz, D.; Henrich, D.; Duhmke, E.

1989-01-01

Acceleration of fast low-angle-shot (FLASH) MR imaging to about 200 msec measuring time on dedicated MR systems is called snapshot FLASH MR imaging. It snaps real-time series of MR images of the MR relaxation and of physiologic motions with nearly absent motion and susceptibility artifacts. Results in animals (4.7T) and human volunteers (2.0T) show plain vascular and cardiac snapshot FLASH MR images obtained as single shot, triggered reconstructed motion, or real-time films. The reduction of artifacts and the high resolution (triggered, three-dimensional moving heart images are possible) result in favorable applications in myocardial and great vascular disease

Effect of nitrate, carbonate/bicarbonate, humic acid, and H2O2 on the kinetics and degradation mechanism of Bisphenol-A during UV photolysis.

Science.gov (United States)

Kang, Young-Min; Kim, Moon-Kyung; Zoh, Kyung-Duk

2018-08-01

In this study, the effects of natural water components (nitrate, carbonate/bicarbonate, and humic acid) on the kinetics and degradation mechanisms of bisphenol A (BPA) during UV-C photolysis and UV/H 2 O 2 reaction were examined. The presence of NO 3 - (0.04-0.4 mM) and CO 3 2- /HCO 3 - (0.4-4 mM) ions increased BPA degradation during UV photolysis. Humic acid less than 3 mg/L promoted BPA degradation, but greater than 3 mg/L of humic acid inhibited BPA degradation. During the UV/H 2 O 2 reaction, all water matrix components acted as radical scavengers in the order of humic acid > CO 3 2- /HCO 3 -  > NO 3 - . All of the degradation reactions agreed with the pseudo-first-order kinetics. While eight byproducts (m/z = 122, 136, 139, 164, 181, 244, 273, 289) were identified in UV-C/NO 3 - photolysis reaction, four (m/z = 122, 136, 164, 244) and three byproducts (m/z = 122, 136, 164) were observed during UV-C/NO 3 - /CO 3 2- /HCO 3 - and UV-C/CO 3 2- /HCO 3 - reactions. Nitrogenated and hydrogenated byproducts were first observed during the UV-C/NO 3 - photolysis, but only hydrogenated byproducts as adducts were detected during the UV-C/NO 3 - /CO 3 2- /HCO 3 - photolysis. Nitrogenated and hydrogenated byproducts were formed in the early stage of degradation by OH or NO 2 radicals, and these byproducts were subsequently degraded into smaller compounds with further reaction during UV-C/NO 3 - and UV-C/NO 3 - /CO 3 2- /HCO 3 - reactions. In contrast, BPA was directly degraded into smaller compounds by β-scission of the isopropyl group by CO 3 - /HCO 3 radicals during UV-C/CO 3 2- /HCO 3 - reaction. Our results imply that the water components can change the degradation mechanism of BPA during UV photolysis. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

The in vitro photolysis of whole rat lenses using focused 290nm laser radiation

International Nuclear Information System (INIS)

Hibbard, L.B.; Kirk, N.J.; Borkman, R.F.

1985-01-01

Whole rat lenses have been irradiated with a UV laser at 290 or 298 nm focused to a 0.08 mm diameter spot. The irradiated spot was analyzed using fluorescence spectroscopy and it was observed that the intensity of fluorescence fell as the irradiation proceeded. These observations were interpreted in terms of a model which postulates photolysis of tryptophan, primarily present as residues in lens proteins, and formation of photoproducts which absorb the UV laser radiation to an ever-increasing extent as the irradiation proceeds. Evidence is also presented which indicates that an observed fast component of the tryptophan fluorescence decay results from local heating of the lens tissues due to energy dissipation by the laser. Tryptophan residues can be photolyzed by UV light in the whole lens, in vitro, in a fashion entirely analogous to that reported previously only for lens protein solutions. The photochemical behavior of lens protein solutions is relevant to whole lens photolysis and no special protective mechanism appears to be operative in the intact organ. (author)

Theoretical investigation of flash vaporisation in a screw expander

Science.gov (United States)

Vasuthevan, Hanushan; Brümmer, Andreas

2017-08-01

In the present study flash vaporisation of liquid injection in a twin screw expander for a Trilateral Flash Cycle (TFC) is examined theoretically. The TFC process comprises a pressure increase in the working fluid, followed by heating the liquid close to boiling point. The hot liquid is injected into the working chamber of a screw expander. During this process the pressure of the liquid drops below the saturation pressure, while the temperature of the liquid remains virtually constant. Hence the liquid is superheated and in a metastable state. The liquid jet seeks to achieve a stable state in thermodynamic equilibrium and is therefore partially vaporised. This effect is referred to as flash vaporisation. Accordingly, a two-phase mixture, consisting of vapour and liquid, exists in the working chamber. Thermodynamic simulations were carried out using water as the working fluid for representative screw expander geometry. The simulations presented are performed from two different aspects during the filling process of a screw expander. The first case is the vaporisation of the injected liquid in a state of thermodynamic equilibrium, whereby the two-phase mixture is treated entirely as a compressible and homogeneous gas. The second case considers flashing efficiency. It describes the quantity of flashed vapour and consists of a liquid and vapour domain. Both models are compared and analysed with respect to the operational behaviour of a screw expander.

A novel method to alleviate flash-line defects in coining process

KAUST Repository

Xu, Jiangping

2013-04-01

We employ a finite element framework based on a dynamic explicit algorithm to predict the flash-line defects in the coining process. The distribution of the flash-line is obtained by building a radial friction work model at the element level. The elasto-plastic behavior of porous materials undergoing large deformations is considered where the constitutive level updates are the result of a local variational minimization problem. We study the material flow at different strokes of the die across the entire coining process and observe that the change in the flow direction of the material in the rim region may contribute to the flash lines. Our proposed framework shows that a part of the rim region in which the flash-line defects appear is consistent with the reported experimental results. We also propose a novel method of redesigning the rim geometry of the workpiece to alleviate the flash-line defects which also shows good agreement with experiments. © 2012 Elsevier Inc. All rights reserved.

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.

The benefit of high-resolution operational weather forecasts for flash flood warning

Directory of Open Access Journals (Sweden)

J. Younis

2008-07-01

Full Text Available In Mediterranean Europe, flash flooding is one of the most devastating hazards in terms of loss of human life and infrastructures. Over the last two decades, flash floods have caused damage costing a billion Euros in France alone. One of the problems of flash floods is that warning times are very short, leaving typically only a few hours for civil protection services to act. This study investigates if operationally available short-range numerical weather forecasts together with a rainfall-runoff model can be used for early indication of the occurrence of flash floods.

One of the challenges in flash flood forecasting is that the watersheds are typically small, and good observational networks of both rainfall and discharge are rare. Therefore, hydrological models are difficult to calibrate and the simulated river discharges cannot always be compared with ground measurements. The lack of observations in most flash flood prone basins, therefore, necessitates the development of a method where the excess of the simulated discharge above a critical threshold can provide the forecaster with an indication of potential flood hazard in the area, with lead times of the order of weather forecasts.

This study is focused on the Cévennes-Vivarais region in the Southeast of the Massif Central in France, a region known for devastating flash floods. This paper describes the main aspects of using numerical weather forecasting for flash flood forecasting, together with a threshold – exceedance. As a case study the severe flash flood event which took place on 8–9 September 2002 has been chosen.

Short-range weather forecasts, from the Lokalmodell of the German national weather service, are used as input for the LISFLOOD model, a hybrid between a conceptual and physically based rainfall-runoff model. Results of the study indicate that high resolution operational weather forecasting combined with a rainfall-runoff model could be useful to

Plasma surface treatment to improve surface charge accumulation and dissipation of epoxy resin exposed to DC and nanosecond-pulse voltages

Science.gov (United States)

Zhang, Cheng; Lin, Haofan; Zhang, Shuai; Xie, Qin; Ren, Chengyan; Shao, Tao

2017-10-01

In this paper, deposition by non-thermal plasma is used as a surface modification technique to change the surface characteristics of epoxy resin exposed to DC and nanosecond-pulse voltages. The corresponding surface characteristics in both cases of DC and nanosecond-pulse voltages before and after the modification are compared and investigated. The measurement of the surface potential provides the surface charge distribution, which is used to show the accumulation and dissipation process of the surface charges. Morphology observations, chemical composition and electrical parameters measurements are used to evaluate the treatment effects. The experimental results show that, before the plasma treatment, the accumulated surface charges in the case of the DC voltage are more than that in the case of the nanosecond-pulse voltage. Moreover, the decay rate of the surface charges for the DC voltage is higher than that for the nanosecond-pulse voltage. However, the decay rate is no more than 41% after 1800 s for both types of voltages. After the plasma treatment, the maximum surface potentials decrease to 57.33% and 32.57% of their values before treatment for the DC and nanosecond-pulse voltages, respectively, indicating a decrease in the accumulated surface charges. The decay rate exceeds 90% for both types of voltages. These changes are mainly attributed to a change in the surface nanostructure, an increase in conductivity, and a decrease in the depth of energy level.

Plasma surface treatment to improve surface charge accumulation and dissipation of epoxy resin exposed to DC and nanosecond-pulse voltages

International Nuclear Information System (INIS)

Zhang, Cheng; Lin, Haofan; Zhang, Shuai; Ren, Chengyan; Shao, Tao; Xie, Qin

2017-01-01

In this paper, deposition by non-thermal plasma is used as a surface modification technique to change the surface characteristics of epoxy resin exposed to DC and nanosecond-pulse voltages. The corresponding surface characteristics in both cases of DC and nanosecond-pulse voltages before and after the modification are compared and investigated. The measurement of the surface potential provides the surface charge distribution, which is used to show the accumulation and dissipation process of the surface charges. Morphology observations, chemical composition and electrical parameters measurements are used to evaluate the treatment effects. The experimental results show that, before the plasma treatment, the accumulated surface charges in the case of the DC voltage are more than that in the case of the nanosecond-pulse voltage. Moreover, the decay rate of the surface charges for the DC voltage is higher than that for the nanosecond-pulse voltage. However, the decay rate is no more than 41% after 1800 s for both types of voltages. After the plasma treatment, the maximum surface potentials decrease to 57.33% and 32.57% of their values before treatment for the DC and nanosecond-pulse voltages, respectively, indicating a decrease in the accumulated surface charges. The decay rate exceeds 90% for both types of voltages. These changes are mainly attributed to a change in the surface nanostructure, an increase in conductivity, and a decrease in the depth of energy level. (paper)

Flash Floods Simulation using a Physical-Based Hydrological Model at Different Hydroclimatic Regions

Science.gov (United States)

Saber, Mohamed; Kamil Yilmaz, Koray

2016-04-01

Currently, flash floods are seriously increasing and affecting many regions over the world. Therefore, this study will focus on two case studies; Wadi Abu Subeira, Egypt as arid environment, and Karpuz basin, Turkey as Mediterranean environment. The main objective of this work is to simulate flash floods at both catchments considering the hydrometeorological differences between them which in turn effect their flash flood behaviors. An integrated methodology incorporating Hydrological River Basin Environmental Assessment Model (Hydro-BEAM) and remote sensing observations was devised. Global Satellite Mapping of Precipitation (GSMAP) were compared with the rain gauge network at the target basins to estimate the bias in an effort to further use it effectively in simulation of flash floods. Based on the preliminary results of flash floods simulation on both basins, we found that runoff behaviors of flash floods are different due to the impacts of climatology, hydrological and topographical conditions. Also, the simulated surface runoff hydrographs are reasonably coincide with the simulated ones. Consequently, some mitigation strategies relying on this study could be introduced to help in reducing the flash floods disasters at different climate regions. This comparison of different climatic basins would be a reasonable implication for the potential impact of climate change on the flash floods frequencies and occurrences.

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)

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)

1997-12-31

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)

Hybrid micromachining using a nanosecond pulsed laser and micro EDM

International Nuclear Information System (INIS)

Kim, Sanha; Chung, Do Kwan; Shin, Hong Shik; Chu, Chong Nam; Kim, Bo Hyun

2010-01-01

Micro electrical discharge machining (micro EDM) is a well-known precise machining process that achieves micro structures of excellent quality for any conductive material. However, the slow machining speed and high tool wear are main drawbacks of this process. Though the use of deionized water instead of kerosene as a dielectric fluid can reduce the tool wear and increase the machine speed, the material removal rate (MRR) is still low. In contrast, laser ablation using a nanosecond pulsed laser is a fast and non-wear machining process but achieves micro figures of rather low quality. Therefore, the integration of these two processes can overcome the respective disadvantages. This paper reports a hybrid process of a nanosecond pulsed laser and micro EDM for micromachining. A novel hybrid micromachining system that combines the two discrete machining processes is introduced. Then, the feasibility and characteristics of the hybrid machining process are investigated compared to conventional EDM and laser ablation. It is verified experimentally that the machining time can be effectively reduced in both EDM drilling and milling by rapid laser pre-machining prior to micro EDM. Finally, some examples of complicated 3D micro structures fabricated by the hybrid process are shown

A note on supersonic flow control with nanosecond plasma actuator

Science.gov (United States)

Zheng, J. G.; Cui, Y. D.; Li, J.; Khoo, B. C.

2018-04-01

A concept study on supersonic flow control using nanosecond pulsed plasma actuator is conducted by means of numerical simulation. The nanosecond plasma discharge is characterized by the generation of a micro-shock wave in ambient air and a residual heat in the discharge volume arising from the rapid heating of near-surface gas by the quick discharge. The residual heat has been found to be essential for the flow separation control over aerodynamic bodies like airfoil and backward-facing step. In this study, novel experiment is designed to utilize the other flow feature from discharge, i.e., instant shock wave, to control supersonic flow through shock-shock interaction. Both bow shock in front of a blunt body and attached shock anchored at the tip of supersonic projectile are manipulated via the discharged-induced shock wave in an appropriate manner. It is observed that drag on the blunt body is reduced appreciably. Meanwhile, a lateral force on sharp-edged projectile is produced, which can steer the body and give it an effective angle of attack. This opens a promising possibility for extending the applicability of this flow control technique in supersonic flow regime.

Insight into electronic mechanisms of nanosecond-laser ablation of silicon

International Nuclear Information System (INIS)

Marine, Wladimir; Patrone, Lionel; Ozerov, Igor; Bulgakova, Nadezhda M.

2008-01-01

We present experimental and theoretical studies of nanosecond ArF excimer laser desorption and ablation of silicon with insight into material removal mechanisms. The experimental studies involve a comprehensive analysis of the laser-induced plume dynamics and measurements of the charge gained by the target during irradiation time. At low laser fluences, well below the melting threshold, high-energy ions with a narrow energy distribution are observed. When the fluence is increased, a thermal component of the plume is formed superimposing on the nonthermal ions, which are still abundant. The origin of these ions is discussed on the basis of two modeling approaches, thermal and electronic, and we analyze the dynamics of silicon target excitation, heating, melting, and ablation. An electronic model is developed that provides insight into the charge-carrier transport in the target. We demonstrate that, contrary to a commonly accepted opinion, a complete thermalization between the electron and lattice subsystems is not reached during the nanosecond-laser pulse action. Moreover, the charging effects can retard the melting process and have an effect on the overall target behavior and laser-induced plume dynamics

Transient-Absorption Spectroscopy of Cis-Trans Isomerization of N,N-dimethyl-4,4'-Azodianiline with 3D-Printed Temperature-Controlled Sample Holder

Science.gov (United States)

Kosenkov, Dmytro; Shaw, James; Zuczek, Jennifer; Kholod, Yana

2016-01-01

The laboratory unit demonstrates a project based approach to teaching physical chemistry laboratory where upper-division undergraduates carry out a transient-absorption experiment investigating the kinetics of cis-trans isomerization of N,N-dimethyl-4,4'-azodianiline. Students participate in modification of a standard flash-photolysis spectrometer…

Impacts of aerosol direct effects on tropospheric ozone through changes in atmospheric dynamics and photolysis rates

Science.gov (United States)

Aerosol direct effects (ADE), i.e., scattering and absorption of incoming solar radiation, reduce radiation reaching the ground and the resultant photolysis attenuation can decrease O3 formation in polluted areas. One the other hand, evidence also suggests that ADE associated coo...

Efficacy of Escitalopram for Hot Flashes in Healthy Menopausal Women: A Randomized Controlled Trial

Science.gov (United States)

Freeman, Ellen W.; Guthrie, Katherine A.; Caan, Bette; Sternfeld, Barbara; Cohen, Lee S.; Joffe, Hadine; Carpenter, Janet S.; Anderson, Garnet L.; Larson, Joseph C.; Ensrud, Kristine E.; Reed, Susan; Newton, Katherine M.; Sherman, Sheryl; Sammel, Mary D.; La Croix, Andrea Z.

2011-01-01

Context Concerns for the risks of hormone therapy have resulted in its decline and a demand for non-hormonal treatments with demonstrated efficacy for hot flashes. Objective Determine the efficacy and tolerability of 10–20 mg/day escitalopram, a selective serotonin reuptake inhibitor, in alleviating the frequency, severity and bother of menopausal hot flashes. Design, Setting and Patients Randomized, double-blind, placebo-controlled, parallel arm trial for 8 weeks in a sample stratified by race (African American n=95; white n=102) and conducted at 4 MsFlash network sites between July 2009 and June 2010. Of 205 women randomized, 194 (95%) completed week 8 (intervention endpoint), and 183 completed post-treatment follow-up. Main Outcome Measures Primary outcomes were the frequency and severity of hot flashes assessed by prospective daily diaries. Secondary outcomes were hot flash "bother" recorded on daily diaries and clinical improvement (hot flash frequency >=50% decrease from baseline). Results Hot flash frequency was 9.78/day (SD 5.60) at baseline. At week 8, reduction in hot flash frequency was greater in the escitalopram group versus placebo (−4.60, SD 4.28 and −3.20, SD 4.76, respectively, P=0.004). Fifty-five percent of the escitalopram group (versus 36% of the placebo group) reported >=50% decreases in hot flash frequency (P=0.009). Differences in decreases in the severity and bother of hot flashes were significant (P=0.003 and P=0.013, respectively), paralleling the decreases in hot flash frequency. Three weeks after treatment ended, hot flash frequency increased in the escitalopram group to the level of the placebo group, which remained stable in the follow-up interval (P=0.020). Overall discontinuation due to side effects was 4% (7 drug, 2 placebo). Conclusion Escitalopram 10–20 mg/day provides non-hormonal off-label treatment for menopausal hot flashes that is effective and well-tolerated in healthy women. PMID:21245182

Flashing liquid jets and two-phase droplet dispersion

International Nuclear Information System (INIS)

Cleary, Vincent; Bowen, Phil; Witlox, Henk

2007-01-01

The large-scale release of a liquid contained at upstream conditions above its local atmospheric boiling point is a scenario often given consideration in process industry risk analysis. Current-hazard quantification software often employs simplistic equilibrium two-phase approaches. Scaled water experiments have been carried out measuring droplet velocity and droplet size distributions for a range of exit orifice aspect ratios (L/d) and conditions representing low to high superheat. 2D Phase-Doppler Anemometry has been utilised to characterise droplet kinematics and spray quality. Droplet size correlations have been developed for non-flashing, the transition between non-flashing and flashing, and fully flashing jets. Using high-speed shadowography, transition between regimes is defined in terms of criteria identified in the external flow structure. An overview companion paper provides a wider overview of the problem and reports implementation of these correlations into consequence models and subsequent validation. The fluid utilised throughout is water, hence droplet correlations are developed in non-dimensional form to allow extrapolation to other fluids through similarity scaling, although verification of model performance for other fluids is required in future studies. Data is reduced via non-dimensionalisation in terms of the Weber number and Jakob number, essentially representing the fluid mechanics and thermodynamics of the system, respectively. A droplet-size distribution correlation has also been developed, conveniently presented as a volume undersize distribution based on the Rosin-Rammler distribution. Separate correlations are provided for sub-cooled mechanical break-up and fully flashing jets. This form of correlation facilitates rapid estimates of likely mass rainout quantities, as well as full distribution information for more rigorous two-phase thermodynamic modelling in the future

Implementation of Power Efficient Flash Analogue-to-Digital Converter

Directory of Open Access Journals (Sweden)

Taninki Sai Lakshmi

2014-01-01

Full Text Available An efficient low power high speed 5-bit 5-GS/s flash analogue-to-digital converter (ADC is proposed in this paper. The designing of a thermometer code to binary code is one of the exacting issues of low power flash ADC. The embodiment consists of two main blocks, a comparator and a digital encoder. To reduce the metastability and the effect of bubble errors, the thermometer code is converted into the gray code and there after translated to binary code through encoder. The proposed encoder is thus implemented by using differential cascade voltage switch logic (DCVSL to maintain high speed and low power dissipation. The proposed 5-bit flash ADC is designed using Cadence 180 nm CMOS technology with a supply rail voltage typically ±0.85 V. The simulation results include a total power dissipation of 46.69 mW, integral nonlinearity (INL value of −0.30 LSB and differential nonlinearity (DNL value of −0.24 LSB, of the flash ADC.

Kinetic determinations of accurate relative oxidation potentials of amines with reactive radical cations.

Science.gov (United States)

Gould, Ian R; Wosinska, Zofia M; Farid, Samir

2006-01-01

Accurate oxidation potentials for organic compounds are critical for the evaluation of thermodynamic and kinetic properties of their radical cations. Except when using a specialized apparatus, electrochemical oxidation of molecules with reactive radical cations is usually an irreversible process, providing peak potentials, E(p), rather than thermodynamically meaningful oxidation potentials, E(ox). In a previous study on amines with radical cations that underwent rapid decarboxylation, we estimated E(ox) by correcting the E(p) from cyclic voltammetry with rate constants for decarboxylation obtained using laser flash photolysis. Here we use redox equilibration experiments to determine accurate relative oxidation potentials for the same amines. We also describe an extension of these experiments to show how relative oxidation potentials can be obtained in the absence of equilibrium, from a complete kinetic analysis of the reversible redox kinetics. The results provide support for the previous cyclic voltammetry/laser flash photolysis method for determining oxidation potentials.

Rate constant for the reaction of atomic oxygen with phosphine at 298 K

Science.gov (United States)

Stief, L. J.; Payne, W. A.; Nava, D. F.

1987-01-01

The rate constant for the reaction of atomic oxygen with phosphine has been measured at 298 K using flash photolysis combined with time-resolved detection of O(3P) via resonance fluorescence. Atomic oxygen was produced by flash photolysis of N2O or NO highly diluted in argon. The results were shown to be independent of (PH3), (O), total pressure and the source of O(3P). The mean value of all the experiments is k1 = (3.6 + or -0.8) x 10 to the -11th cu cm/s (1 sigma). Two previous measurements of k1 differed by more than an order of magnitude, and the results support the higher value obtained in a discharge flow-mass spectrometry study. A comparison with rate data for other atomic and free radical reactions with phosphine is presented, and the role of these reactions in the aeronomy or photochemistry of Jupiter and Saturn is briefly considered.

Boiling water reactor stability revisited: The effects of flashing

International Nuclear Information System (INIS)

Yadigaroglu, G.; Askari, B.

2005-01-01

There are numerous investigations of two-phase flow stability with particular emphasis to BWR stability; these have become increasingly sophisticated and complete over the years. The basic features of a new development and frequency-domain code capable of considering all the channels (bundles) in a BWR, flashing of the coolant at low pressure, full coupling with 3D, two-group neutronics, etc. are described. The basic thermal-hydraulic model is used to study the effects of flashing on stability in a BWR-like channel. The behavior of the channel is highly dynamic. Contrary to what could have been intuitively guessed, the effect of flashing is stabilizing; the reasons and mechanisms leading to this are discussed

Boiling water reactor stability revisited: The effects of flashing

Energy Technology Data Exchange (ETDEWEB)

Yadigaroglu, G. [Institute of Energy Technology, Swiss Federal Institute of Technology, ETH, ETH-Zentrum, CLT-C1, CH-8092 Zurich (Switzerland)]. E-mail: yadi@ethz.ch; Askari, B. [Institute of Energy Technology, Swiss Federal Institute of Technology, ETH, ETH-Zentrum, CLT-C1, CH-8092 Zurich (Switzerland)

2005-05-01

There are numerous investigations of two-phase flow stability with particular emphasis to BWR stability; these have become increasingly sophisticated and complete over the years. The basic features of a new development and frequency-domain code capable of considering all the channels (bundles) in a BWR, flashing of the coolant at low pressure, full coupling with 3D, two-group neutronics, etc. are described. The basic thermal-hydraulic model is used to study the effects of flashing on stability in a BWR-like channel. The behavior of the channel is highly dynamic. Contrary to what could have been intuitively guessed, the effect of flashing is stabilizing; the reasons and mechanisms leading to this are discussed.

WMO World Record Lightning Extremes: Longest Reported Flash Distance and Longest Reported Flash Duration.

Science.gov (United States)

Lang, Timothy J; Pédeboy, Stéphane; Rison, William; Cerveny, Randall S; Montanyà, Joan; Chauzy, Serge; MacGorman, Donald R; Holle, Ronald L; Ávila, Eldo E; Zhang, Yijun; Carbin, Gregory; Mansell, Edward R; Kuleshov, Yuriy; Peterson, Thomas C; Brunet, Manola; Driouech, Fatima; Krahenbuhl, Daniel S

2017-06-01

A World Meteorological Organization weather and climate extremes committee has judged that the world's longest reported distance for a single lightning flash occurred with a horizontal distance of 321 km (199.5 mi) over Oklahoma in 2007, while the world's longest reported duration for a single lightning flash is an event that lasted continuously for 7.74 seconds over southern France in 2012. In addition, the committee has unanimously recommended amendment of the AMS Glossary of Meteorology definition of lightning discharge as a "series of electrical processes taking place within 1 second" by removing the phrase "within one second" and replacing with "continuously." Validation of these new world extremes (a) demonstrates the recent and on-going dramatic augmentations and improvements to regional lightning detection and measurement networks, (b) provides reinforcement regarding the dangers of lightning, and (c) provides new information for lightning engineering concerns.

Generation of fast-rise time, repetitive, (sub) nanosecond, high-voltage pulses

NARCIS (Netherlands)

Huiskamp, T.; Pemen, A.J.M.

2017-01-01

In this contribution we present our fast-rise time nanosecond pulse generator, capable of generating up to 50 kV (positive and negative) rectangular pulses at a repetition rate of up to 1 kHz and with a rise time of less than 200 picoseconds. We focus on the general concepts involved in the design

Study of the selective abstration reaction of the hydrogen atom in the radiolysis and photolysis of alkane mixture at 77 K

International Nuclear Information System (INIS)

Guedes, S.M.L.

1979-01-01

The occurence of the selective abstraction reaction of the solute hydrogen atom by hydrogen atom produced during radiolysis or photolysis of the systems such as neopentane/cyclo-hexane/HI, neopentane/2,3 dimethylbutane, n-pentane/HI/cyclo-hexane and cyclo-hexane/HI/n-pentane, at 77 K is studied. Experiments have been undertaken on the kinetics nature of the active species, the H atom, during radiolysis and photolysis of the neopentane/cyclo-hexane/HI system at 77 K, presenting competitive reactions. Studies have also been made on the occurrence of the selective abstraction reaction in inverted systems, in which the concentrations of the components of a system are so much altered that the solute becomes the solvent and vice-versa, in the other system. By means of photolysis at 77 K, it has been observed that for the two systems constitued by the cyclo-hexane and n-pentane the selective abstraction reaction occurs. However, for radiolysis of that same two systems it has been observed that only the hydrogen atom abstraction reaction corresponding to the solvent occurs. (Author) [pt

Degradation of Paracetamol by Photolysis Using C-N-codoped TiO2

OpenAIRE

Vanny Yulia Safitri; Adlis Santoni; Diana Vanda Wellia; Khoiriah Khoiriah; Safni Safni

2017-01-01

Paracetamol is generally used as analgesic and antipyretic drugs. Contamination paracetamol in the environment can occur because of waste material disposal from production site and immediate disposal of household that cause water pollution. Paracetamol is degraded by photolysis method under irradiation 10 watt UV-light (λ=365 nm), visible-light (Philips LED 13 watt 1400 lux) and solar-light with and without addition C-N-codoped TiO2catalyst. The solution is analyzed by UV-Vis spectrophotomete...

Flashing evaporation under different pressure levels

International Nuclear Information System (INIS)

Liao, Yixiang; Lucas, Dirk; Krepper, Eckhard; Rzehak, Roland

2013-01-01

Highlights: • CFD simulation based on two-fluid model for flashing boiling inside a vertical pipe. • Effect of pressure level on the maximum thermal energy available for evaporation. • Effect of presumed bubble size on the onset of flashing as well as evaporation rate. • Effect of pressure level on the critical bubble size that can start stable flashing. • Effect of pressure level on nucleation rate and mechanism. - Abstract: Flashing evaporation of water inside a vertical pipe under four pressure levels is investigated both experimentally and numerically. In the experiment depressurization is realized through a blow-off valve, and the evaporation rate is controlled by the opening rate and degree of the valve. In the CFD simulation phase change is assumed to be caused by thermal heat transfer between steam–water interface and the surrounding water. Consequently, the evaporation rate is determined by heat transfer coefficient, interfacial area density as well as liquid superheat degree. The simulated temporal course of cross-section averaged steam volume fraction is compared with the measured one. It is found that the increasing rate and maximum value of steam volume fraction is over-predicted under low-pressure conditions, which is mainly caused by the neglect of bubble growth in the mono-dispersed simulation. The agreement is notably improved by performing poly-dispersed simulations with the inhomogeneous MUSIG approach (IMUSIG). On the other hand an underestimation of the maximum steam volume fraction is observed in high-pressure cases, since the contribution of nucleation to the total steam generation rate becomes large as the system pressure increases. Reliable models for nucleation rate as well as bubble detachment size are indispensable for reliable predictions. An effect of the system pressure level on the nucleation mechanism is observed in the experiment

The role of direct photolysis and indirect photochemistry in the environmental fate of ethylhexyl methoxy cinnamate (EHMC) in surface waters

International Nuclear Information System (INIS)

Vione, D.; Calza, P.; Galli, F.; Fabbri, D.; Santoro, V.; Medana, C.

2015-01-01

The aquatic environmental fate of ethylhexyl methoxy cinnamate (EHMC), one of the most used UVB filters worldwide, was studied by assessing its environmental persistence and photoinduced transformations. The role of direct and indirect photolysis was evaluated. Direct photolysis was shown to play a key role, and this process is expected to be the main attenuation route of EHMC in sunlit surface waters. In contrast, the reaction with ·OH radicals would be negligible and that with "3CDOM* would at most be a secondary process. The measurement of the quantum yield of direct photolysis and of the rate constants of reaction with photogenerated transient species (or, sometimes, the use of reasonable values for the latter) allowed the prediction of the EHMC half-life time in surface waters, by means of a validated photochemical model. The predicted EHMC lifetime is of the order of hours to a few days in fair-weather summertime, and the main factors controlling the EHMC phototransformation in sunlit surface waters would be the water depth and the dissolved organic carbon (DOC) content. The formation of transformation products (TPs) was followed as well via HPLC/HRMS. Three TPs were detected in the samples exposed to UVA radiation, while one additional TP was detected in the samples exposed to UVB radiation. The detected TPs comprised 4-methoxybenzaldehyde, a hydroxylated derivative and dimeric species. Through the use of heterogeneous photocatalysis with TiO_2, seven additional TPs were identified, most of them resulting from the further degradation of primary TPs formed through direct photolysis and that might be detected in aquatic systems as well. The photodegradation of EHMC in the presence of TiO_2 yielded more toxic TPs than the parent compound (as determined with the Vibrio fischeri Microtox assay). The increased toxicity is partially accounted for by the formation of 4-methoxybenzaldehyde. - Highlights: • Study of the photolytic and photocatalytic transformation

The role of direct photolysis and indirect photochemistry in the environmental fate of ethylhexyl methoxy cinnamate (EHMC) in surface waters

Energy Technology Data Exchange (ETDEWEB)

Vione, D. [Department of Chemistry, University of Torino, via P. Giuria 5, 10125 Torino (Italy); Calza, P., E-mail: paola.calza@unito.it [Department of Chemistry, University of Torino, via P. Giuria 5, 10125 Torino (Italy); Galli, F.; Fabbri, D. [Department of Chemistry, University of Torino, via P. Giuria 5, 10125 Torino (Italy); Santoro, V.; Medana, C. [Department of Molecular Biotechnology and Health Sciences, University of Torino, via P. Giuria 5, 10125 Torino (Italy)

2015-12-15

The aquatic environmental fate of ethylhexyl methoxy cinnamate (EHMC), one of the most used UVB filters worldwide, was studied by assessing its environmental persistence and photoinduced transformations. The role of direct and indirect photolysis was evaluated. Direct photolysis was shown to play a key role, and this process is expected to be the main attenuation route of EHMC in sunlit surface waters. In contrast, the reaction with ·OH radicals would be negligible and that with {sup 3}CDOM* would at most be a secondary process. The measurement of the quantum yield of direct photolysis and of the rate constants of reaction with photogenerated transient species (or, sometimes, the use of reasonable values for the latter) allowed the prediction of the EHMC half-life time in surface waters, by means of a validated photochemical model. The predicted EHMC lifetime is of the order of hours to a few days in fair-weather summertime, and the main factors controlling the EHMC phototransformation in sunlit surface waters would be the water depth and the dissolved organic carbon (DOC) content. The formation of transformation products (TPs) was followed as well via HPLC/HRMS. Three TPs were detected in the samples exposed to UVA radiation, while one additional TP was detected in the samples exposed to UVB radiation. The detected TPs comprised 4-methoxybenzaldehyde, a hydroxylated derivative and dimeric species. Through the use of heterogeneous photocatalysis with TiO{sub 2}, seven additional TPs were identified, most of them resulting from the further degradation of primary TPs formed through direct photolysis and that might be detected in aquatic systems as well. The photodegradation of EHMC in the presence of TiO{sub 2} yielded more toxic TPs than the parent compound (as determined with the Vibrio fischeri Microtox assay). The increased toxicity is partially accounted for by the formation of 4-methoxybenzaldehyde. - Highlights: • Study of the photolytic and photocatalytic

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.

Introduction to FLASH 3.0, with application to supersonic turbulence

International Nuclear Information System (INIS)

Dubey, A; Reid, L B; Fisher, R

2008-01-01

FLASH is a flexible, modular and parallel application code capable of simulating the compressible, reactive flows found in many astrophysical environments. It is a collection of inter-operable modules which can be combined to generate different applications. FLASH is gaining increasing recognition as a community code with a fairly wide external user base. Unlike other component-based codes that have historically met with varying degrees of success. FLASH started out as a more traditional scientific code and evolved into a modular one as insights were gained into manageability, extensibility and efficiency. As a result, the development of the code has been, and continues to be, driven by the dual goals of application requirements and modularity. In this tutorial paper, we give an overview of the FLASH code architecture and capabilities. We also include an example of a customized application adapted from the sample applications provided with the code distribution.

Integrated circuits with emitter coupling and their application in nanosecond nuclear electronics

International Nuclear Information System (INIS)

Basiladze, S.G.

1976-01-01

Principal static and dynamic characteristics are considered of integrated circuits with emitter coupling, as well as problems of signal transmission. Diagrams are given of amplifiers, discriminators, time interval drivers, generators, etc. Systems and units of nanosecond electronics employing integrated circuits with emitter coupling are briefly described

A Novel Dual Traffic/Flash Flood Monitoring System Using Passive Infrared/Ultrasonic Sensors

KAUST Repository

Mousa, Mustafa

2015-10-19

Floods are the most common type of natural disaster, causing thousands of casualties every year. Among these events, urban flash floods are particularly deadly because of the short timescales on which they occur, and because of the high concentration of population in cities. Since most flash flood casualties are caused by a lack of information, it is critical to generate accurate and detailed warnings of flash floods. However, deploying an infrastructure that solely monitor flash floods makes little economic sense, since the average periodicity of catastrophic flash floods exceeds the lifetime of a typical sensor network. To address this issue, we propose a new sensing device that can simultaneously monitor urban flash floods and another phenomenon of interest (traffic congestion on the present case). This sensing device is based on the combination of an ultrasonic rangefinder with one or multiple remote temperature sensors. We show an implementation of this device, and illustrate its performance in both traffic flow and flash flood sensing. Field data shows that the sensor can detect vehicles with a 99% accuracy, in addition to estimating their speed and classifying them in function of their length. The same sensor can also monitor urban water levels with an accuracy of less than 2 cm. Two of the sensors have been deployed in a flood prone area, where they captured the only (minor) flash flood that occurred over the one-year test period, with no false detection, and an agreement in the estimated water level estimate (during the flash flood event) of about 2 cm.

Efficacy of a biobehavioral intervention for hot flashes: a randomized controlled pilot study.

Science.gov (United States)

Barton, Debra L; Schroeder, Kelliann C Fee; Banerjee, Tanima; Wolf, Sherry; Keith, Timothy Z; Elkins, Gary

2017-07-01

The need for effective nonhormonal treatments for hot flash management without unwanted side effects continues. The primary aim of this pilot study was to evaluate the effect of combining a nonhormonal pharmacologic agent with a behavioral treatment for hot flash reduction. Seventy-one postmenopausal women were randomized to one of four groups: venlafaxine 75 mg + hypnosis (VH) versus venlafaxine 75 mg + sham hypnosis (VSH) versus a placebo pill + hypnosis (PH) versus placebo pill + sham hypnosis (PSH). Women recorded hot flash severity and frequency in a daily diary, in real time. The intrapatient difference in hot flash score (frequency × severity) at 8 weeks was analyzed using a General Estimating Equation model, using VSH as the referent arm, controlling for baseline hot flashes. The active arms including PH or VH were not statistically significantly different than VSH (P = 0.34, P = 0.05, respectively). Women in each active arm reported hot flash reductions of about 50%, with the PSH group reporting a 25% reduction. Women receiving the PSH reported statistically significantly smaller reductions in hot flash score than women in the referent VSH arm (P = 0.001). There were no significant negative side effects during the course of the study. Hypnosis alone reduced hot flashes equal to venlafaxine alone, but the combination of hypnosis and venlafaxine did not reduce hot flashes more than either treatment alone. More research is needed to clarify whether combining hypnosis with a different antidepressant would provide synergistic benefits.

A Novel Dual Traffic/Flash Flood Monitoring System Using Passive Infrared/Ultrasonic Sensors

KAUST Repository

Mousa, Mustafa; Odat, Enas M.; Claudel, Christian

2015-01-01

Floods are the most common type of natural disaster, causing thousands of casualties every year. Among these events, urban flash floods are particularly deadly because of the short timescales on which they occur, and because of the high concentration of population in cities. Since most flash flood casualties are caused by a lack of information, it is critical to generate accurate and detailed warnings of flash floods. However, deploying an infrastructure that solely monitor flash floods makes little economic sense, since the average periodicity of catastrophic flash floods exceeds the lifetime of a typical sensor network. To address this issue, we propose a new sensing device that can simultaneously monitor urban flash floods and another phenomenon of interest (traffic congestion on the present case). This sensing device is based on the combination of an ultrasonic rangefinder with one or multiple remote temperature sensors. We show an implementation of this device, and illustrate its performance in both traffic flow and flash flood sensing. Field data shows that the sensor can detect vehicles with a 99% accuracy, in addition to estimating their speed and classifying them in function of their length. The same sensor can also monitor urban water levels with an accuracy of less than 2 cm. Two of the sensors have been deployed in a flood prone area, where they captured the only (minor) flash flood that occurred over the one-year test period, with no false detection, and an agreement in the estimated water level estimate (during the flash flood event) of about 2 cm.

Nanosecond laser ablation of target Al in a gaseous medium: explosive boiling

Science.gov (United States)

Mazhukin, V. I.; Mazhukin, A. V.; Demin, M. M.; Shapranov, A. V.

2018-03-01

An approximate mathematical description of the processes of homogeneous nucleation and homogeneous evaporation (explosive boiling) of a metal target (Al) under the influence of ns laser radiation is proposed in the framework of the hydrodynamic model. Within the continuum approach, a multi-phase, multi-front hydrodynamic model and a computational algorithm are designed to simulate nanosecond laser ablation of the metal targets immersed in gaseous media. The proposed approach is intended for modeling and detailed analysis of the mechanisms of heterogeneous and homogeneous evaporation and their interaction with each other. It is shown that the proposed model and computational algorithm allow modeling of interrelated mechanisms of heterogeneous and homogeneous evaporation of metals, manifested in the form of pulsating explosive boiling. Modeling has shown that explosive evaporation in metals is due to the presence of a near-surface temperature maximum. It has been established that in nanosecond pulsed laser ablation, such exposure regimes can be implemented in which phase explosion is the main mechanism of material removal.

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.

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"

Femtosecond versus nanosecond laser machining: comparison of induced stresses and structural changes in silicon wafers

International Nuclear Information System (INIS)

Amer, M.S.; El-Ashry, M.A.; Dosser, L.R.; Hix, K.E.; Maguire, J.F.; Irwin, Bryan

2005-01-01

Laser micromachining has proven to be a very successful tool for precision machining and microfabrication with applications in microelectronics, MEMS, medical device, aerospace, biomedical, and defense applications. Femtosecond (FS) laser micromachining is usually thought to be of minimal heat-affected zone (HAZ) local to the micromachined feature. The assumption of reduced HAZ is attributed to the absence of direct coupling of the laser energy into the thermal modes of the material during irradiation. However, a substantial HAZ is thought to exist when machining with lasers having pulse durations in the nanosecond (NS) regime. In this paper, we compare the results of micromachining a single crystal silicon wafer using a 150-femtosecond and a 30-nanosecond lasers. Induced stress and amorphization of the silicon single crystal were monitored using micro-Raman spectroscopy as a function of the fluence and pulse duration of the incident laser. The onset of average induced stress occurs at lower fluence when machining with the femtosecond pulse laser. Induced stresses were found to maximize at fluence of 44 J cm -2 and 8 J cm -2 for nanosecond and femtosecond pulsed lasers, respectively. In both laser pulse regimes, a maximum induced stress is observed at which point the induced stress begins to decrease as the fluence is increased. The maximum induced stress was comparable at 2.0 GPa and 1.5 GPa for the two lasers. For the nanosecond pulse laser, the induced amorphization reached a plateau of approximately 20% for fluence exceeding 22 J cm -2 . For the femtosecond pulse laser, however, induced amorphization was approximately 17% independent of the laser fluence within the experimental range. These two values can be considered nominally the same within experimental error. For femtosecond laser machining, some effect of the laser polarization on the amount of induced stress and amorphization was also observed

High precision timing in a FLASH

Energy Technology Data Exchange (ETDEWEB)

Hoek, Matthias; Cardinali, Matteo; Dickescheid, Michael; Schlimme, Soeren; Sfienti, Concettina; Spruck, Bjoern; Thiel, Michaela [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany)

2016-07-01

A segmented highly precise start counter (FLASH) was designed and constructed at the Institute for Nuclear Physics in Mainz. Besides determining a precise reference time, a Time-of-Flight measurement can be performed with two identical FLASH units. Thus, particle identification can be provided for mixed hadron beam environments. The detector design is based on the detection of Cherenkov light produced in fused silica radiator bars with fast multi-anode MCP-PMTs. The segmentation of the radiator improves the timing resolution while allowing a coarse position resolution along one direction. Both, the arrival time and the Time-over-Threshold are determined by the readout electronics, which enables walk correction of the arrival time. The performance of two FLASH units was investigated in test experiments at the Mainz Microton (MAMI) using an electron beam with an energy of 855 MeV and at CERN's PS T9 beam line with a mixed hadron beam with momenta between 3-8 GeV/c. Effective Time-walk correction methods based on Time-over-Threshold were developed for the data analysis. The achieved Time-Of-Flight resolution after applying all corrections was found to be 70 ps. Furthermore, the PID and position resolution capabilities are discussed in this contribution.

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.

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

A comparison of colour, shape, and flash induced illusory line motion.

Science.gov (United States)

Hamm, Jeff P

2017-04-01

When a bar suddenly appears between two boxes, the bar will appear to shoot away from the box that matches it in colour or in shape-a phenomenon referred to as attribute priming of illusory line motion (ILM; colour ILM and shape ILM, respectively). If the two boxes are identical, ILM will still occur away from a box if it changes luminance shortly before the presentation of the bar ( flash ILM). This flash condition has been suggested to produce the illusory motion due to the formation of an attentional gradient surrounding the flashed location. However, colour ILM and shape ILM cannot be explained by an attentional gradient as there is no way for attention to select the matching box prior to the presentation of the bar. These findings challenge the attentional gradient explanation for ILM, but only if it is assumed that ILM arises for the same underlying reason. Two experiments are presented that address the question of whether or not flash ILM is the same as colour ILM or shape ILM. The results suggest that while colour ILM and shape ILM reflect a common illusion, flash ILM arises for a different reason. Therefore, the attentional gradient explanation for flash ILM is not refuted by the occurrence of colour ILM or shape ILM, which may reflect transformational apparent motion (TAM).

A simple sub-nanosecond ultraviolet light pulse generator with high repetition rate and peak power.

Science.gov (United States)

Binh, P H; Trong, V D; Renucci, P; Marie, X

2013-08-01

We present a simple ultraviolet sub-nanosecond pulse generator using commercial ultraviolet light-emitting diodes with peak emission wavelengths of 290 nm, 318 nm, 338 nm, and 405 nm. The generator is based on step recovery diode, short-circuited transmission line, and current-shaping circuit. The narrowest pulses achieved have 630 ps full width at half maximum at repetition rate of 80 MHz. Optical pulse power in the range of several hundreds of microwatts depends on the applied bias voltage. The bias voltage dependences of the output optical pulse width and peak power are analysed and discussed. Compared to commercial UV sub-nanosecond generators, the proposed generator can produce much higher pulse repetition rate and peak power.

Plasma-Enhanced Combustion of Hydrocarbon Fuels and Fuel Blends Using Nanosecond Pulsed Discharges

Energy Technology Data Exchange (ETDEWEB)

Cappelli, Mark; Mungal, M Godfrey

2014-10-28

This project had as its goals the study of fundamental physical and chemical processes relevant to the sustained premixed and non-premixed jet ignition/combustion of low grade fuels or fuels under adverse flow conditions using non-equilibrium pulsed nanosecond discharges.

Temporal shaping of nanosecond CO2 laser pulses in multiphoton saturable absorbers

International Nuclear Information System (INIS)

Haglund, R.F. Jr.

1981-01-01

It was shown that substantial temporal distortion of nanosecond 10.6 μm laser pulses occurs in traversing multiphoton saturable absorbers. The risetime and pulse delay effects appear to depend both on fluence and wavelength, and to be qualitatively consistent with predictions of a simple two-level absorption model

Instrumentation

Energy Technology Data Exchange (ETDEWEB)

None

1973-07-01

Developments discussed include a transistorized- power supply for the Beckman DU spectrophotometer, a master clock pulse generator, a modular printing unit, a flash photolysis setup, a glove box assembly for a Perkin-Elmer infrared spectrophotometer, and a Faraday balance for measuring the magnetic susceptibilities of actinide compounds. (WHK)

Model of UV flashes due to gigantic blue jets

International Nuclear Information System (INIS)

Milikh, G M; Shneider, M N

2008-01-01

Analysis of UV flashes observed by the UV detector on board the 'Tatiana' microsatellite suggests, based on their location, pulse width and energy of the source of the photons, that the flashes were generated by gigantic blue jets (GBJs). Presented in this paper is a numerical model of UV flashes due to a bunch of long streamers which form a leader, a prong such as that observed in a GBJ. Using a previously developed model of upward propagation of a long streamer in the exponential atmosphere the paper describes temporal evolution of the UV flux generated by a bunch of long streamers, in the given spectral range 300-400 nm used by the UV detector on board 'Tatiana'. The model is in agreement with the observations.

Machine protection for FLASH and the European XFEL

Energy Technology Data Exchange (ETDEWEB)

Froehlich, Lars

2009-05-15

The Free-Electron Laser in Hamburg (FLASH) and the future European X-Ray Free-Electron Laser (XFEL) are sources of brilliant extremeultraviolet and X-ray radiation pulses. Both facilities are based on superconducting linear accelerators (linacs) that can produce and transport electron beams of high average power. With up to 90 kW or up to 600 kW of power, respectively, these beams hold a serious potential to damage accelerator components. This thesis discusses several passive and active machine protection measures needed to ensure safe operation. At FLASH, dark current from the rf gun electron source has activated several accelerator components to unacceptable radiation levels. Its transport through the linac is investigated with detailed tracking simulations using a parallelized and enhanced version of the tracking code Astra; possible remedies are evaluated. Beam losses can lead to the demagnetization of permanent magnet insertion devices. A number of beam loss scenarios typical for FLASH are investigated with shower simulations. A shielding setup is designed and its efficiency is evaluated. For the design parameters of FLASH, it is concluded that the average relative beam loss in the undulators must be controlled to a level of about 10{sup -8}. FLASH is equipped with an active machine protection system (MPS) comprising more than 80 photomultiplier-based beam loss monitors and several subsystems. The maximum response time to beam losses is less than 4 {mu}s. Setup procedures and calibration algorithms for MPS subsystems and components are introduced and operational problems are addressed. Finally, an architecture for a fully programmable machine protection system for the XFEL is presented. Several options for the topology of this system are reviewed, with the result that an availability goal of at least 0.999 for the MPS is achievable with moderate hardware requirements. (orig.)

Machine protection for FLASH and the European XFEL

International Nuclear Information System (INIS)

Froehlich, Lars

2009-05-01

The Free-Electron Laser in Hamburg (FLASH) and the future European X-Ray Free-Electron Laser (XFEL) are sources of brilliant extremeultraviolet and X-ray radiation pulses. Both facilities are based on superconducting linear accelerators (linacs) that can produce and transport electron beams of high average power. With up to 90 kW or up to 600 kW of power, respectively, these beams hold a serious potential to damage accelerator components. This thesis discusses several passive and active machine protection measures needed to ensure safe operation. At FLASH, dark current from the rf gun electron source has activated several accelerator components to unacceptable radiation levels. Its transport through the linac is investigated with detailed tracking simulations using a parallelized and enhanced version of the tracking code Astra; possible remedies are evaluated. Beam losses can lead to the demagnetization of permanent magnet insertion devices. A number of beam loss scenarios typical for FLASH are investigated with shower simulations. A shielding setup is designed and its efficiency is evaluated. For the design parameters of FLASH, it is concluded that the average relative beam loss in the undulators must be controlled to a level of about 10 -8 . FLASH is equipped with an active machine protection system (MPS) comprising more than 80 photomultiplier-based beam loss monitors and several subsystems. The maximum response time to beam losses is less than 4 μs. Setup procedures and calibration algorithms for MPS subsystems and components are introduced and operational problems are addressed. Finally, an architecture for a fully programmable machine protection system for the XFEL is presented. Several options for the topology of this system are reviewed, with the result that an availability goal of at least 0.999 for the MPS is achievable with moderate hardware requirements. (orig.)

FLASH Technology: Full-Scale Hospital Waste Water Treatments Adopted in Aceh

Science.gov (United States)

Rame; Tridecima, Adeodata; Pranoto, Hadi; Moesliem; Miftahuddin

2018-02-01

A Hospital waste water contains a complex mixture of hazardous chemicals and harmful microbes, which can pose a threat to the environment and public health. Some efforts have been carried out in Nangroe Aceh Darussalam (Aceh), Indonesia with the objective of treating hospital waste water effluents on-site before its discharge. Flash technology uses physical and biological pre-treatment, followed by advanced oxidation process based on catalytic ozonation and followed by GAC and PAC filtration. Flash Full-Scale Hospital waste water Treatments in Aceh from different district have been adopted and investigated. Referring to the removal efficiency of macro-pollutants, the collected data demonstrate good removal efficiency of macro-pollutants using Flash technologies. In general, Flash technologies could be considered a solution to the problem of managing hospital waste water.

X-RAY AND GAMMA-RAY FLASHES FROM TYPE Ia SUPERNOVAE?

International Nuclear Information System (INIS)

Hoeflich, Peter; Schaefer, Bradley E.

2009-01-01

We investigate two potential mechanisms that will produce X-ray and γ-ray flashes from Type Ia supernovae (SN-Ia). The first mechanism is the breakout of the thermonuclear burning front as it reaches the surface of the white dwarf (WD). The second mechanism is the interaction of the rapidly expanding envelope with material within an accretion disk in the progenitor system. Our study is based on the delayed detonation scenario because this can account for the majority of light curves, spectra, and statistical properties of 'Branch-normal' SN-Ia. Based on detailed radiation-hydro calculations which include nuclear networks, we find that both mechanisms produce brief flashes of high-energy radiation with peak luminosities of 10 48 -10 50 erg s -1 . The breakout from the WD surface produces flashes with a rapid exponential decay by 3-4 orders of magnitude on timescales of a few tenths of a second and with most of the radiation in the X-ray and soft γ-ray range. The shocks produced in gases in and around the binary will produce flashes with a characteristic duration of a few seconds with most of the radiation coming out as X-rays and γ-rays. In both mechanisms, we expect a fast rise and slow decline and, after the peak, an evolution from hard to softer radiation due to adiabatic expansion. In many cases, flashes from both mechanisms will be superposed. The X- and γ-ray visibility of an SN-Ia will depend strongly on self-absorption within the progenitor system, specifically on the properties of the accretion disk and its orientation toward the observer. Such X-ray and γ-ray flashes could be detected as triggered events by gamma-ray burst (GRB) detectors on satellites, with events in current GRB catalogs. We have searched through the GRB catalogs (for the BATSE, HETE, and Swift experiments) for GRBs that occur at the extrapolated time of explosion and in the correct direction for known Type Ia supernovae with radial velocity of less than 3000 km s -1 . For the Burst

Flash Builder 4 and Flex 4 Bible

CERN Document Server

Gassner, David

2010-01-01

A complete and thorough reference for developers on the new Flex 4 platform. Create desktop applications that behave identically on Windows, Mac OS X, and Linux with Adobe's new Flash Builder 4 platform and this in-depth guide. The book's tutorials and explanations walk you step-by-step through Flash Builder's new, faster tools; the new framework for generating code; how to connect to popular application servers; upgrading from Flex 3; and much more.: Shows you how to create rich applications for the Web and desktop with the very latest version of Flex, with detailed coverage for both new and

Acupuncture as Treatment of Hot Flashes and the Possible Role of Calcitonin Gene-Related Peptide

Directory of Open Access Journals (Sweden)

Anna-Clara E. Spetz Holm

2012-01-01

Full Text Available The mechanisms behind hot flashes in menopausal women are not fully understood. The flashes in women are probably preceded by and actually initiated by a sudden downward shift in the set point for the core body temperature in the thermoregulatory center that is affected by sex steroids, β-endorphins, and other central neurotransmitters. Treatments that influence these factors may be expected to reduce hot flashes. Since therapy with sex steroids for hot flashes has appeared to cause a number of side effects and risks and women with hot flashes and breast cancer as well as men with prostate cancer and hot flashes are prevented from sex steroid therapy there is a great need for alternative therapies. Acupuncture affecting the opioid system has been suggested as an alternative treatment option for hot flashes in menopausal women and castrated men. The heat loss during hot flashes may be mediated by the potent vasodilator and sweat gland activator calcitonin gene-related peptide (CGRP the concentration of which increases in plasma during flashes in menopausal women and, according to one study, in castrated men with flushes. There is also evidence for connections between the opioid system and the release of CGRP. In this paper we discuss acupuncture as a treatment alternative for hot flashes and the role of CGRP in this context.

Flash Study Analysis and the Music Learning Pro-Files Project

Science.gov (United States)

Cremata, Radio; Pignato, Joseph; Powell, Bryan; Smith, Gareth Dylan

2016-01-01

This paper introduces the Music Learning Profiles Project, and its methodological approach, flash study analysis. Flash study analysis is a method that draws heavily on extant qualitative approaches to education research, to develop broad understandings of music learning in diverse contexts. The Music Learning Profiles Project (MLPP) is an…

Motorist actions at a crosswalk with an in-pavement flashing light system.

Science.gov (United States)

Karkee, Ganesh J; Nambisan, Shashi S; Pulugurtha, Srinivas S

2010-12-01

An in-pavement flashing light system is used at crosswalks to alert motorists and pedestrians of possible conflicts and to influence their behavior to enhance safety. The relative behaviors of the drivers and the pedestrians affect safety. An evaluation of motorist behavior at a pedestrian crosswalk with an in-pavement flashing light system is presented in this manuscript. Field observations provide the basis to evaluate motorist behavior at a crosswalk with an in-pavement flashing light system. Outcomes of pedestrian and motorists actions were observed to quantify measures of effectiveness (MOEs) such as yielding behavior of motorists, vehicle speeds, and yielding distance from the crosswalk. A before-and-after study design was used. The before condition was prior to the activation of the in-pavement flashing light system and the after condition was after the activation of the in-pavement flashing light system. The study was conducted on a relatively low-volume roadway located in the Henderson, Nevada. The significance of the differences in the MOEs between the 2 study periods was evaluated using statistical analysis tools such as a one-tailed test for proportions and the Welch-Satterthwaite t-test. The results show that the installation of the in-pavement flashing light system increased the yielding behavior of motorists significantly (P pavement flashing light system is seen to be effective to improve motorists' yielding behavior and the speeds of vehicles were also observed to decrease in the presence of pedestrians.

Investigation of local optical inhomogeneities in flashlamp photolysis lasers

Energy Technology Data Exchange (ETDEWEB)

Alekhin, B V; Borovkov, V V; Lazhintsev, B V; Nor-Arenian, V A; Sukhanov, L V; Ustinenko, V A

1979-09-01

Local changes in the refractive index which occur in the active medium under flashlamp-excited photolysis laser action are examined experimentally. Under conditions of the inverse population storage and suppression of the laser action by a strong quencher, local inhomogeneities have been absent. It is shown that the stimulated emission is inhomogeneous over the active medium and features regular character with the radiation density modulation within 20-30 percent and with typical size of inhomogeneities of not greater than 0.5 mm. On the basis of experimental results and estimation, a conclusion is drawn that the local optical inhomogeneities are caused by gasdynamic displacements of the gas due to different heat evolutions in the regions of the radiation density maximum and minimum.

Efficient temporal compression of coherent nanosecond pulses in compact SBS generator-amplifier setup

NARCIS (Netherlands)

Schiemann, S.; Ubachs, W.M.G.; Hogervorst, W.

1997-01-01

A pulse compressor based on stimulated Brillouin scattering (SBS) in liquids is experimentally and theoretically investigated. It allows for the compression of Fourier-transform limited nanosecond pulses of several hundreds of millijoules of energy with both high conversion efficiency and a high

Nano-Second Isomers in Neutron-Rich Ni Region Produced by Deep-Inelastic Collisions

International Nuclear Information System (INIS)

Ishii, T.; Asai, M.; Matsuda, M.; Ichikawa, S.; Makishima, A.; Hossain, I.; Kleinheinz, P.; Ogawa, M.

2001-01-01

Nuclear structure of the doubly magic 68 Ni and its neighbors has been studied by spectroscopic techniques. Developing a new instrument isomer-scope, we have measured γ rays from nano-second isomers produced in heavy-ion deep-inelastic collisions with great sensitivity. (author)

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.

Metabolic activity in the insular cortex and hypothalamus predicts hot flashes: an FDG-PET study.

Science.gov (United States)

Joffe, Hadine; Deckersbach, Thilo; Lin, Nancy U; Makris, Nikos; Skaar, Todd C; Rauch, Scott L; Dougherty, Darin D; Hall, Janet E

2012-09-01

Hot flashes are a common side effect of adjuvant endocrine therapies (AET; leuprolide, tamoxifen, aromatase inhibitors) that reduce quality of life and treatment adherence in breast cancer patients. Because hot flashes affect only some women, preexisting neurobiological traits might predispose to their development. Previous studies have implicated the insula during the perception of hot flashes and the hypothalamus in thermoregulatory dysfunction. The aim of the study was to understand whether neurobiological factors predict hot flashes. [18F]-Fluorodeoxyglucose (FDG) positron emission tomography (PET) brain scans coregistered with structural magnetic resonance imaging were used to determine whether metabolic activity in the insula and hypothalamic thermoregulatory and estrogen-feedback regions measured before and in response to AET predict hot flashes. Findings were correlated with CYP2D6 genotype because of CYP2D6 polymorphism associations with tamoxifen-induced hot flashes. We measured regional cerebral metabolic rate of glucose uptake (rCMRglu) in the insula and hypothalamus on FDG-PET. Of 18 women without hot flashes who began AET, new-onset hot flashes were reported by 10 (55.6%) and were detected objectively in nine (50%) participants. Prior to the use of all AET, rCMRglu in the insula (P ≤ 0.01) and hypothalamic thermoregulatory (P = 0.045) and estrogen-feedback (P = 0.007) regions was lower in women who reported developing hot flashes. In response to AET, rCMRglu was further reduced in the insula in women developing hot flashes (P ≤ 0.02). Insular and hypothalamic rCMRglu levels were lower in intermediate than extensive CYP2D6 metabolizers. Trait neurobiological characteristics predict hot flashes. Genetic variability in CYP2D6 may underlie the neurobiological predisposition to hot flashes induced by AET.

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...

The Adjoint Method for Gradient-based Dynamic Optimization of UV Flash Processes

DEFF Research Database (Denmark)

Ritschel, Tobias Kasper Skovborg; Capolei, Andrea; Jørgensen, John Bagterp

2017-01-01

This paper presents a novel single-shooting algorithm for gradient-based solution of optimal control problems with vapor-liquid equilibrium constraints. Dynamic optimization of UV flash processes is relevant in nonlinear model predictive control of distillation columns, certain two-phase flow pro......-component flash process which demonstrate the importance of the optimization solver, the compiler, and the linear algebra software for the efficiency of dynamic optimization of UV flash processes....

Flash flood disasters analysis and evaluation: a case study of Yiyang County in China

Science.gov (United States)

Li, Haichen; Zhang, Xiaolei; Li, Qing; Qin, Tao; Lei, Xiaohui

2018-03-01

Global climate change leads to the more extreme precipitation and more flash flood disasters, which is a serious threat to the mountain inhabitants. To prevent flash flood disasters, China started flash flood disaster control planning and other projects from 2006. Among those measures, non-engineering measures are effective and economical. This paper introduced the framework of flash flood disaster analysis and evaluation in China, followed by a case study of Yiyang County.

A thermal model for nanosecond pulsed laser ablation of aluminum

Directory of Open Access Journals (Sweden)

Yu Zhang

2017-07-01

Full Text Available In order to simulate the nanosecond pulsed laser ablation of aluminum, a novel model was presented for the target ablation and plume expansion. The simulation of the target ablation was based on one-dimensional heat conduction, taking into account temperature dependent material properties, phase transition, dielectric transition and phase explosion. While the simulation of the plume expansion was based on one-dimensional gas-dynamical equation, taking into account ionization, plume absorption and shielding. By coupling the calculations of the target ablation and plume expansion, the characteristics of the target and plume were obtained. And the calculated results were in good agreement with the experimental data, in terms of ablation threshold and depth within the fluence range of the tested laser. Subsequently, investigations were carried out to analyze the mechanisms of nanosecond pulsed laser ablation. The calculated results showed that the maximum surface temperature remained at about 90% of the critical temperature (0.9Tc due to phase explosion. Moreover, the plume shielding has significant effects on the laser ablation, and the plume shielding proportion increase as the laser fluence increasing. The ambient pressure belows 100 Pa is more suitable for laser ablation, which can obtained larger ablation depth.

Picosecond absorption relaxation measured with nanosecond laser photoacoustics.

Science.gov (United States)

Danielli, Amos; Favazza, Christopher P; Maslov, Konstantin; Wang, Lihong V

2010-10-18

Picosecond absorption relaxation-central to many disciplines-is typically measured by ultrafast (femtosecond or picosecond) pump-probe techniques, which however are restricted to optically thin and weakly scattering materials or require artificial sample preparation. Here, we developed a reflection-mode relaxation photoacoustic microscope based on a nanosecond laser and measured picosecond absorption relaxation times. The relaxation times of oxygenated and deoxygenated hemoglobin molecules, both possessing extremely low fluorescence quantum yields, were measured at 576 nm. The added advantages in dispersion susceptibility, laser-wavelength availability, reflection sensing, and expense foster the study of natural-including strongly scattering and nonfluorescent-materials.

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. © 2013 The Fisheries Society of the British Isles.

Prediction of the Flash Point of Binary and Ternary Straight-Chain Alkane Mixtures

Directory of Open Access Journals (Sweden)

X. Li

2014-01-01

Full Text Available The flash point is an important physical property used to estimate the fire hazard of a flammable liquid. To avoid the occurrence of fire or explosion, many models are used to predict the flash point; however, these models are complex, and the calculation process is cumbersome. For pure flammable substances, the research for predicting the flash point is systematic and comprehensive. For multicomponent mixtures, especially a hydrocarbon mixture, the current research is insufficient to predict the flash point. In this study, a model was developed to predict the flash point of straight-chain alkane mixtures using a simple calculation process. The pressure, activity coefficient, and other associated physicochemical parameters are not required for the calculation in the proposed model. A series of flash points of binary and ternary mixtures of straight-chain alkanes were determined. The results of the model present consistent experimental results with an average absolute deviation for the binary mixtures of 0.7% or lower and an average absolute deviation for the ternary mixtures of 1.03% or lower.

Flash flood modeling with the MARINE hydrological distributed model

Science.gov (United States)

Estupina-Borrell, V.; Dartus, D.; Ababou, R.

2006-11-01

Flash floods are characterized by their violence and the rapidity of their occurrence. Because these events are rare and unpredictable, but also fast and intense, their anticipation with sufficient lead time for warning and broadcasting is a primary subject of research. Because of the heterogeneities of the rain and of the behavior of the surface, spatially distributed hydrological models can lead to a better understanding of the processes and so on they can contribute to a better forecasting of flash flood. Our main goal here is to develop an operational and robust methodology for flash flood forecasting. This methodology should provide relevant data (information) about flood evolution on short time scales, and should be applicable even in locations where direct observations are sparse (e.g. absence of historical and modern rainfalls and streamflows in small mountainous watersheds). The flash flood forecast is obtained by the physically based, space-time distributed hydrological model "MARINE'' (Model of Anticipation of Runoff and INondations for Extreme events). This model is presented and tested in this paper for a real flash flood event. The model consists in two steps, or two components: the first component is a "basin'' flood module which generates flood runoff in the upstream part of the watershed, and the second component is the "stream network'' module, which propagates the flood in the main river and its subsidiaries. The basin flash flood generation model is a rainfall-runoff model that can integrate remotely sensed data. Surface hydraulics equations are solved with enough simplifying hypotheses to allow real time exploitation. The minimum data required by the model are: (i) the Digital Elevation Model, used to calculate slopes that generate runoff, it can be issued from satellite imagery (SPOT) or from French Geographical Institute (IGN); (ii) the rainfall data from meteorological radar, observed or anticipated by the French Meteorological Service (M�

Adobe Flash as a medium for online experimentation: a test of reaction time measurement capabilities.

Science.gov (United States)

Reimers, Stian; Stewart, Neil

2007-08-01

Adobe Flash can be used to run complex psychological experiments over the Web. We examined the reliability of using Flash to measure reaction times (RTs) using a simple binary-choice task implemented both in Flash and in a Linux-based system known to record RTs with millisecond accuracy. Twenty-four participants were tested in the laboratory using both implementations; they also completed the Flash version on computers of their own choice outside the lab. RTs from the trials run on Flash outside the lab were approximately 20 msec slower than those from trials run on Flash in the lab, which in turn were approximately 10 msec slower than RTs from the trials run on the Linux-based system (baseline condition). RT SDs were similar in all conditions, suggesting that although Flash may overestimate RTs slightly, it does not appear to add significant noise to the data recorded.

Megavolt nanosecond generator with semiconductor current breaker

CERN Document Server

Bushlyakov, A I; Rukin, S N; Slovikovskij, B G; Timoshenkov, S P

2002-01-01

The heavy-current nanosecond generator with the pulse capacity up to 1.6 GW and output voltage of 0.5-1 MW is described. The generator contains four capacity storages, one induction storage and six solid body commutators: one thyristor, four magnetic commutators and a semiconductor current breaker on the SOS-diodes. The results of studies on the energy change-over efficiency through a semiconductor breaker by various external resistance loads as well as the results of the thermal and frequency tests are presented. It is established that selection of the optimal cooling system provides for the generator continuous mode of operation with the pulse sequence frequency from 300 Hz up to 850 Hz

Synoptic-scale atmospheric conditions associated with flash flooding in watersheds of the Catskill Mountains, New York, USA

Science.gov (United States)

Teale, N. G.; Quiring, S. M.

2015-12-01

Understanding flash flooding is important in unfiltered watersheds, such as portions of the New York City water supply system (NYCWSS), as water quality is degraded by turbidity associated with flooding. To further understand flash flooding in watersheds of the NYCWSS, synoptic-scale atmospheric conditions most frequently associated with flash flooding between 1987 and 2013 were examined. Flash floods were identified during this time period using USGS 15-minute discharge data at the Esopus Creek near Allaben, NY and Neversink River at Claryville, NY gauges. Overall, 25 flash floods were detected, occurring over 17 separate flash flood days. These flash flood days were compared to the days on which flash flood warnings encompassing the study area was issued by the National Weather Service. The success rate for which the flash flood warnings for Ulster County coincided with flash flood in the study watershed was 0.09, demonstrating the highly localized nature of flash flooding in the Catskill Mountain region. The synoptic-scale atmospheric patterns influencing the study area were characterized by a principal component analysis and k-means clustering of NCEP/NCAR 500 mb geopotential height reanalysis data. This procedure was executed in Spatial Synoptic Typer Tools 4.0. While 17 unique synoptic patterns were identified, only 3 types were strongly associated with flash flooding events. A strong southwesterly flow suggesting advection of moisture from the Atlantic Ocean and Gulf of Mexico is shown in composites of these 3 types. This multiscalar study thereby links flash flooding in the NYCWSS with synoptic-scale atmospheric circulation.Understanding flash flooding is important in unfiltered watersheds, such as portions of the New York City water supply system (NYCWSS), as water quality is degraded by turbidity associated with flooding. To further understand flash flooding in watersheds of the NYCWSS, synoptic-scale atmospheric conditions most frequently associated with

Nitrate photolysis in salty snow

Science.gov (United States)

Donaldson, D. J.; Morenz, K.; Shi, Q.; Murphy, J. G.

2016-12-01

Nitrate photolysis from snow can have a significant impact on the oxidative capacity of the local atmosphere, but the factors affecting the release of gas phase products are not well understood. Here, we report the first systematic study of the amounts of NO, NO2, and total nitrogen oxides (NOy) emitted from illuminated snow samples as a function of both nitrate and total salt (NaCl and Instant Ocean) concentration. We show that the release of nitrogen oxides to the gas phase is directly related to the expected nitrate concentration in the brine at the surface of the snow crystals, increasing to a plateau value with increasing nitrate, and generally decreasing with increasing NaCl or Instant Ocean (I.O.). In frozen mixed nitrate (25 mM) - salt (0-500 mM) solutions, there is an increase in gas phase NO2 seen at low added salt amounts: NO2 production is enhanced by 35% at low prefreezing [NaCl] and by 70% at similar prefreezing [I.O.]. Raman microscopy of frozen nitrate-salt solutions shows evidence of stronger nitrate exclusion to the air interface in the presence of I.O. than with added NaCl. The enhancement in nitrogen oxides emission in the presence of salts may prove to be important to the atmospheric oxidative capacity in polar regions.

Synthesis of pure ozone by nanosecond discharge at cryogenic temperatures

International Nuclear Information System (INIS)

Amirov, R.H.; Asinovsky, E.I.; Samoilov, I.S.

1996-01-01

Synthesis of pure ozone by nanosecond discharge at cryogenic temperatures was experimentally examined. The average ozone concentration in the volume of the discharge tube was less at cryogenic temperatures than at room temperatures. The production of condensed ozone have been determined by measuring the ozone concentration when the walls was heated and ozone evaporated. The energy yield of ozone generation at cryogenic temperatures has been calculated. The maximum value was 200 g/kWh

Nanosecond pulse-width electron diode based on dielectric wall accelerator technology

Energy Technology Data Exchange (ETDEWEB)

Zhao, Quantang, E-mail: zhaoquantang@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Z.M.; Yuan, P.; Cao, S.C.; Shen, X.K.; Jing, Y. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Yu, C.S. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Z.P.; Liu, M.; Xiao, R.Q. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zong, Y.; Wang, Y.R. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhao, H.W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2013-11-21

An electron diode using a short section of dielectric wall accelerator (DWA) has been under development at the Institute of Modern Physics (IMP), Chinese Academy of Sciences. Tests have been carried out with spark gap switches triggered by lasers. The stack voltage efficiency of a four-layer of Blumleins reached about 60–70% with gas filled spark gap switching. The generated pulse voltage of peak amplitude of 23 kV and pulse width of 5 ns is used to extract and accelerate an electron beam of 320 mA, measured by a fast current transformer. A nanosecond pulse width electron diode was achieved successfully. Furthermore, the principle of a DWA is well proven and the development details and discussions are presented in this article. -- Highlights: •The key technology of DWA, including switches and pulse forming lines were studied. •The SiC PCSS obtained from Shanghai Institute were tested. •Two layers ZIP lines (new structure) and four layers Blumlein lines were studied with laser triggered spark gap switches. •A nanosecond pulse-width electron diode based on DWA technologies is achieved and studied experimentally. •The principle of DWA is also proved by the diode.

Pattern analysis of laser-tattoo interactions for picosecond- and nanosecond-domain 1,064-nm neodymium-doped yttrium-aluminum-garnet lasers in tissue-mimicking phantom.

Science.gov (United States)

Ahn, Keun Jae; Zheng, Zhenlong; Kwon, Tae Rin; Kim, Beom Joon; Lee, Hye Sun; Cho, Sung Bin

2017-05-08

During laser treatment for tattoo removal, pigment chromophores absorb laser energy, resulting in fragmentation of the ink particles via selective photothermolysis. The present study aimed to outline macroscopic laser-tattoo interactions in tissue-mimicking (TM) phantoms treated with picosecond- and nanosecond-domain lasers. Additionally, high-speed cinematographs were captured to visualize time-dependent tattoo-tissue interactions, from laser irradiation to the formation of photothermal and photoacoustic injury zones (PIZs). In all experimental settings using the nanosecond or picosecond laser, tattoo pigments fragmented into coarse particles after a single laser pulse, and further disintegrated into smaller particles that dispersed toward the boundaries of PIZs after repetitive delivery of laser energy. Particles fractured by picosecond treatment were more evenly dispersed throughout PIZs than those fractured by nanosecond treatment. Additionally, picosecond-then-picosecond laser treatment (5-pass-picosecond treatment + 5-pass-picosecond treatment) induced greater disintegration of tattoo particles within PIZs than picosecond-then-nanosecond laser treatment (5-pass-picosecond treatment + 5-pass-nanosecond treatment). High-speed cinematography recorded the formation of PIZs after repeated reflection and propagation of acoustic waves over hundreds of microseconds to a few milliseconds. The present data may be of use in predicting three-dimensional laser-tattoo interactions and associated reactions in surrounding tissue.

LOFAR lightning imaging : mapping lightning with nanosecond precision

NARCIS (Netherlands)

Hare, B.M.; Scholten, O.; Bonardi, A.; Buitink, S.; Corstanje, A.; Ebert, U.; Falcke, H.; Hörandel, J.R.; Leijnse, H.; Mitra, P.; Mulrey, K.; Nelles, A.; Rachen, J. P.; Rossetto, L.; Rutjes, C.; Schellart, P.; Thoudam, S.; Trinh, T.N.G.; ter Veen, S.; Winchen, T.

2018-01-01

Lightning mapping technology has proven instrumental in understanding lightning. In this work we present a pipeline that can use lightning observed by the LOw-Frequency ARray (LOFAR) radio telescope to construct a 3-D map of the flash. We show that LOFAR has unparalleled precision, on the order of

Reduced order modeling of flashing two-phase jets

Energy Technology Data Exchange (ETDEWEB)

Gurecky, William, E-mail: william.gurecky@utexas.edu; Schneider, Erich, E-mail: eschneider@mail.utexas.edu; Ballew, Davis, E-mail: davisballew@utexas.edu

2015-12-01

Highlights: • Accident simulation requires ability to quickly predict two-phase flashing jet's damage potential. • A reduced order modeling methodology informed by experimental or computational data is described. • Zone of influence volumes are calculated for jets of various upstream thermodynamic conditions. - Abstract: In the event of a Loss of Coolant Accident (LOCA) in a pressurized water reactor, the escaping coolant produces a highly energetic flashing jet with the potential to damage surrounding structures. In LOCA analysis, the goal is often to evaluate many break scenarios in a Monte Carlo style simulation to evaluate the resilience of a reactor design. Therefore, in order to quickly predict the damage potential of flashing jets, it is of interest to develop a reduced order model that relates the damage potential of a jet to the pressure and temperature upstream of the break and the distance from the break to a given object upon which the jet is impinging. This work presents framework for producing a Reduced Order Model (ROM) that may be informed by measured data, Computational Fluid Dynamics (CFD) simulations, or a combination of both. The model is constructed by performing regression analysis on the pressure field data, allowing the impingement pressure to be quickly reconstructed for any given upstream thermodynamic condition within the range of input data. The model is applicable to both free and fully impinging two-phase flashing jets.

Evaluation of Dietary Intake of Various Vitamins in Menopausal Women with Hot Flashes

Directory of Open Access Journals (Sweden)

Aytekin Tokmak

2014-12-01

Full Text Available Aim: Menopausal hot flashes affect the majority of women. Hormone replacement therapy to reduce the severity of hot flashes is the most effective method. Today, however, due to a number of side effects of hormone therapy more women are seeking alternative treatments such as vitamin pills and herbal products. Previously, various vitamins, minerals and trace elements were studied for this purpose. In this study, our aim was to determine the level of dietary intake of various vitamins in women with hot flashes and to compare them with women who had no complaints. Material and Method: One hundred and seven consecutive women who attended the menopause clinic of our hospital for routine follow up were included in this study. All of the participants were asked about the occurrence of specific menopausal symptoms and completed 92-itm antioxidant nutrient questionnaire developed by Satia. The main parameters recorded for each woman were; age, obstetrical characteristics, body mass index, smoking status, educational level, type of menopause (surgical or natural, duration of menopause, menopausal symptoms, and number and duration of hot flashes. According to the computerized analysis of questionnaire, dietary intake of water-soluble vitamins; B complex and vitamin C, and fat-soluble vitamins; vitamin, A D, E, K were calculated. Results: Patients were divided into two groups with regard to presence of hot flashes, those with hot flashes constituted the study groups (n:75, and others without hot flashes constituted the control group (n:32. The mean age of patients was statistically significantly lower in the study group (p<0,001. The mean duration of menopause was also lower in this group (p<0,001. There were no statistically significant differences between groups in terms of obstetrical characteristics, body mass index, smoking status, educational level, type of menopause (p>0,05. Night sweats and sleep disorders were more common in women with hot flashes

Evaluation of Dietary Intake of Various Vitamins in Menopausal Women with Hot Flashes

Directory of Open Access Journals (Sweden)

Aytekin Tokmak

2016-11-01

Full Text Available Aim: Menopausal hot flashes affect the majority of women. Hormone replacement therapy to reduce the severity of hot flashes is the most effective method. Today, however, due to a number of side effects of hormone therapy more women are seeking alternative treatments such as vitamin pills and herbal products. Previously, various vitamins, minerals and trace elements were studied for this purpose. In this study, our aim was to determine the level of dietary intake of various vitamins in women with hot flashes and to compare them with women who had no complaints. Material and Method: One hundred and seven consecutive women who attended the menopause clinic of our hospital for routine follow up were included in this study. All of the participants were asked about the occurrence of specific menopausal symptoms and completed 92-itm antioxidant nutrient questionnaire developed by Satia. The main parameters recorded for each woman were; age, obstetrical characteristics, body mass index, smoking status, educational level, type of menopause (surgical or natural, duration of menopause, menopausal symptoms, and number and duration of hot flashes. According to the computerized analysis of questionnaire, dietary intake of water-soluble vitamins; B complex and vitamin C, and fat-soluble vitamins; vitamin, A D, E, K were calculated. Results: Patients were divided into two groups with regard to presence of hot flashes, those with hot flashes constituted the study groups (n:75, and others without hot flashes constituted the control group (n:32. The mean age of patients was statistically significantly lower in the study group (p<0,001. The mean duration of menopause was also lower in this group (p<0,001. There were no statistically significant differences between groups in terms of obstetrical characteristics, body mass index, smoking status, educational level, type of menopause (p>0,05. Night sweats and sleep disorders were more common in women with hot flashes

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.

Electrical Safety and Arc Flash Protections

International Nuclear Information System (INIS)

Camp, R.

2008-01-01

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.

THE INFLUENCE OF NANOSECOND ELECTROMAGNETIC PULSES TO OBTAIN TIN AND THE PROPERTIES OF ITS ALLOYS

Directory of Open Access Journals (Sweden)

V. G. Komkov

2012-01-01

Full Text Available Experimentally found that the effect of nanosecond electromagnetic pulses to melt the charge, while the carbon thermal recovery of the tin ore, accelerates the formation of the metallic phase.

Nanosecond pulsed discharges in N2 and N2/H2O mixtures

NARCIS (Netherlands)

Joosten, R.M.; Verreycken, T.; Veldhuizen, van E.M.; Bruggeman, P.J.

2011-01-01

Nanosecond pulsed discharges in N2 and N2/H2O at atmospheric pressure between two pin-shaped electrodes are studied. The evolution of the discharge is investigated with time-resolved imaging and optical emission spectroscopy. The discharge consists of three phases, the ignition (mainly molecular

Nanosecond pulsed laser induced self-organized nano-dots patterns on GaSb surface

Energy Technology Data Exchange (ETDEWEB)

Yoshida, Yutaka, E-mail: yyoshida@cris.hokudai.ac.jp [Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, N8, W13, Kita-ku, Sapporo 060-8628, Hokkaido (Japan); Creative Research Institution Sousei, Hokkaido University, N21, W10, Kita-ku, Sapporo 001-0021, Hokkaido (Japan); Oosawa, Kazuya; Wajima, Jyunya; Watanabe, Seiichi [Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, N8, W13, Kita-ku, Sapporo 060-8628, Hokkaido (Japan); Matsuo, Yasutaka [Research Institute for Electronic Science, Hokkaido University, Sapporo 001-0020, Hokkaido (Japan); Kato, Takahiko [Hitachi Research Laboratory, Hitachi, Ltd., 7-1-1 Omika, Hitachi-shi 319-1292, Ibaraki-ken (Japan); Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, N8, W13, Kita-ku, Sapporo 060-8628, Hokkaido (Japan)

2014-07-01

We report a technique for formation of two-dimensional (2D) nanodot (ND) patterns on gaillium antimoide (GaSb) using a nanosecond pulsed laser irradiation with 532 nm wavelength. The patterns have formed because of the interference and the self-organization under energy deposition of the laser irradiation, which induced the growth of NDs on the local area. The NDs are grown and shrunken in the pattern by energy depositions. In the laser irradiation with average laser energy density of 35 mJ cm⁻², large and small NDs are formed on GaSb surface. The large NDs have grown average diameter from 160 to 200 nm with increase of laser pulses, and the small NDs have shrunken average diameter from 75 to 30 nm. The critical dot size is required about 107 nm for growth of the NDs in the patterns. Nanosecond pulsed laser irradiation can control the self-organized ND size on GaSb in air as a function of the laser pulses.

Design of High-Security USB Flash Drives Based on Chaos Authentication

Directory of Open Access Journals (Sweden)

Teh-Lu Liao

2018-05-01

Full Text Available This paper aims to propose a novel design of high-security USB flash drives with the chaos authentication. A chaos authentication approach with the non-linear encryption and decryption function design is newly proposed and realized based on the controller design of chaos synchronization. To complete the design of high-security USB flash drives, first, we introduce six parameters into the original Henon map to adjust and obtain richer chaotic state responses. Then a discrete sliding mode scheme is proposed to solve the synchronization problem of discrete hyperchaotic Henon maps. The proposed sliding mode controller can ensure the synchronization of the master-slave Henon maps. The selection of the switching surface and the existence of the sliding motion are also addressed. Finally, the obtained results are applied to design a new high-security USB flash drive with chaos authentication. We built discrete hyperchaotic Henon maps in the smartphone (master and microcontroller (slave, respectively. The Bluetooth module is used to communicate between the master and the slave to achieve chaos synchronization such that the same random and dynamical chaos signal can be simultaneously obtained at both the USB flash drive and smartphone, and pass the chaos authentication. When users need to access data in the flash drive, they can easily enable the encryption APP in the smartphone (master for chaos authentication. After completing the chaos synchronization and authentication, the ARM-based microcontroller allows the computer to access the data in the high-security USB flash drive.

Inception and development of voids in flashing liquids

International Nuclear Information System (INIS)

Jones, O.C. Jr.

1979-06-01

Recent work aimed at correctly describing nonequilibrium vapor generation rates in flashing liquids in decompressing flows similar to those which might be encountered in a loss of coolant accident in a nuclear reactor is summarized. Analysis is reviewed which describes the flashing inception superheat in terms of the turbulence intensity for a given expansion rate and initial temperature, and interfacial area density and interfacial heat flux, and the volumetric vapor generation rates. Comparisons with existing data are included and further experiments being undertaken are described, including typical recent results

Prompt and delayed excitation and photolysis of cesium dimers

International Nuclear Information System (INIS)

Davanloo, F.; Collins, C.B.; Inamdar, A.S.; Mehendale, N.Y.; Nagvi, A.S.

1984-01-01

In this work a time-delayed, double resonance technique was used for the study of the state selective photolysis of Cs 2 excited in the yellow range of visible wavelengths. Particular attention being placed on the production of the fine structure components of the 5 2 D and 6 2 P states of Cs and upon the lifetimes of the product populations in the cesium vapor. A quantitative model was constructed to fit the data and rate coefficients were extracted for processes tending to attenuate the product state selectivity. Reported here is what appears to be the first value for the fine-structure mixing cross section for Cs(5 2 D5/2 → 5 2 D 3 /sub 3/2/) of 17 A 2 +-50%, close to the geometric cross section

New principle of feeding for flash evaporation MOCVD devices

International Nuclear Information System (INIS)

Kaul, A.R.; Seleznev, B.V.

1993-01-01

A novel scheme of flash evaporation feeding for MOCVD processes of multi-component oxide films deposition is proposed. The scheme comprises 1) microdozage of organic solution of solid volatile precursors on the glass fiber belt, 2) evaporation of the solvent and 3) flash evaporation of MOC microdoses from the belt. The functioning of the designed feeder is described and the features of proposed scheme in comparison to existing feeding principles are discussed. (orig.)

A novel method of calculating the energy deposition curve of nanosecond pulsed surface dielectric barrier discharge

International Nuclear Information System (INIS)

He, Kun; Wang, Xinying; Lu, Jiayu; Cui, Quansheng; Pang, Lei; Di, Dongxu; Zhang, Qiaogen

2015-01-01

To obtain the energy deposition curve is very important in the fields to which nanosecond pulse dielectric barrier discharges (NPDBDs) are applied. It helps the understanding of the discharge physics and fast gas heating. In this paper, an equivalent circuit model, composed of three capacitances, is introduced and a method of calculating the energy deposition curve is proposed for a nanosecond pulse surface dielectric barrier discharge (NPSDBD) plasma actuator. The capacitance C d and the energy deposition curve E R are determined by mathematically proving that the mapping from C d to E R is bijective and numerically searching one C d that satisfies the requirement for E R to be a monotonically non-decreasing function. It is found that the value of capacitance C d varies with the amplitude of applied pulse voltage due to the change of discharge area and is dependent on the polarity of applied voltage. The bijectiveness of the mapping from C d to E R in nanosecond pulse volumetric dielectric barrier discharge (NPVDBD) is demonstrated and the feasibility of the application of the new method to NPVDBD is validated. This preliminarily shows a high possibility of developing a unified approach to calculate the energy deposition curve in NPDBD. (paper)

Gas phase radiolysis and vacuum ultraviolet photolysis of heterocyclic organic compounds. Progress report, February 1, 1974--February 1, 1975

International Nuclear Information System (INIS)

Scala, A.A.; Salomon, D.; Colon, I.; D'Angona, J.

1975-01-01

In the γ radiolysis of tetrahydrofuran there are pronounced density effects in the pressure range from 0 to 50 Torr with the most important ion-pair yields decreasing as the pressure increases. The relative product yields of the radiolysis is compared with that of xenon photolysis. Possible mechanisms to explain the results obtained are discussed. The ion-pair yields from the γ radiolysis of the heterocyclic amines, ethylenimine, azetidine, pyrrolidine, and piperidine, are determined, and the pressure effects are evaluated. Reactions mechanisms are discussed. The vacuum ultraviolet photolysis products of thietane and tetrahydrothiophene are studied and compared with the γ radiolysis products. Reaction mechanisms are discussed. The status of the construction of a photoionization mass spectrometer and the measurement of the ionization efficiencies and extinction coefficients of organic compounds is reported. (U.S.)

Interactions of numerical and temporal stimulus characteristics on the control of response location by brief flashes of light.

Science.gov (United States)

Fetterman, J Gregor; Killeen, P Richard

2011-09-01

Pigeons pecked on three keys, responses to one of which could be reinforced after 3 flashes of the houselight, to a second key after 6, and to a third key after 12. The flashes were arranged according to variable-interval schedules. Response allocation among the keys was a function of the number of flashes. When flashes were omitted, transitions occurred very late. Increasing flash duration produced a leftward shift in the transitions along a number axis. Increasing reinforcement probability produced a leftward shift, and decreasing reinforcement probability produced a rightward shift. Intermixing different flash rates within sessions separated allocations: Faster flash rates shifted the functions sooner in real time, but later in terms of flash count, and conversely for slower flash rates. A model of control by fading memories of number and time was proposed.

Sodium current inhibition by nanosecond pulsed electric field (nsPEF)--fact or artifact?

NARCIS (Netherlands)

Verkerk, Arie O.; van Ginneken, Antoni C. G.; Wilders, Ronald

2013-01-01

In two recent publications in Bioelectromagnetics it has been demonstrated that the voltage-gated sodium current (I(Na)) is inhibited in response to a nanosecond pulsed electric field (nsPEF). At the same time, there was an increase in a non-inactivating "leak" current (I(leak)), which was

Enhancing cell proliferation by non-contact nanosecond PEF treatment of cell culture vials

NARCIS (Netherlands)

Bree, van J.W.M.; Geysen, J.J.G.; Pemen, A.J.M.

2012-01-01

The applicability of nanosecond pulsed electric fields (nsPEF) has been focused on killing of cells by means of direct contact between the nsPEF electrodes and tissue or liquid, such as in melanoma destruction [1] and sterilization of fluids. Here we present a novel, tabletop device that induces

Nonlinear dynamic model of a gear-rotor-bearing system considering the flash temperature

Science.gov (United States)

Gou, Xiangfeng; Zhu, Lingyun; Qi, Changjun

2017-12-01

The instantaneous flash temperature is an important factor for gears in service. To investigate the effect of the flash temperature of a tooth surface on the dynamics of the spur gear system, a modified nonlinear dynamic model of a gear-rotor-bearing system is established. The factors such as the contact temperature of the tooth surface, time-varying stiffness, tooth surface friction, backlash, the comprehensive transmission error and so on are considered. The flash temperature of a tooth surface of pinion and gear is formulated according to Blok's flash temperature theory. The mathematical expression of the contact temperature of the tooth surface varied with time is derived and the tooth profile deformation caused by the change of the flash temperature of the tooth surface is calculated. The expression of the mesh stiffness varied with the flash temperature of the tooth surface is derived based on Hertz contact theory. The temperature stiffness is proposed and added to the nonlinear dynamic model of the system. The influence of load on the flash temperature of the tooth surface is analyzed in the parameters plane. The variation of the flash temperature of the tooth surface is studied. The numerical results indicate that the calculated method of the flash temperature of the gear tooth surface is effective and it can reflect the rules for the change of gear meshing temperature and sliding of the gear tooth surface. The effects of frequency, backlash, bearing clearance, comprehensive transmission error and time-varying stiffness on the nonlinear dynamics of the system are analyzed according to the bifurcation diagrams, Top Lyapunov Exponent (TLE) spectrums, phase portraits and Poincaré maps. Some nonlinear phenomena such as periodic bifurcation, grazing bifurcation, quasi-periodic bifurcation, chaos and its routes to chaos are investigated and the critical parameters are identified. The results provide an understanding of the system and serve as a useful reference

Flash Extraction and Physicochemical Characterization of Oil from Elaeagnus mollis Diels Seeds.

Science.gov (United States)

Kan, Lina; Wang, Lin; Ding, Qingzhen; Wu, Yanwen; Ouyang, Jie

2017-04-03

A flash extraction method was used to isolate Elaeagnus mollis oil (EMO). The optimal extraction parameters, sample/solvent ratio and extraction temperature, were determined to be 1:10 (g/mL) and 40°C, respectively. Especially, the extraction yield reached 49.30% when the extraction time was as short as 2 min. No obvious difference was observed in fatty acid composition, iodine value, saponification number, total phenolic content and tocopherol content between flash-extracted EMO and Soxhlet-extracted EMO, but their physicochemical values were lower than those of cold-pressed EMO. Cold-pressed EMO had higher oxidation stability, DPPH (1-diphenyl-2-picrylhydrazyl) and hydroxyl radical-scavenging activities than flash-extracted EMO and Soxlet extracted EMO. The flash extraction is demonstrated to be an alternative, efficient method for the vegetable oil production.

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. Copyright © 2012 Elsevier Ltd. All rights reserved.

Magnetic field effects on geminate reactions. Study of anthraquinone - hydrogen donors systems

International Nuclear Information System (INIS)

Vidal, Marie-Helene

1987-01-01

This study is devoted to magnetic field effects on chemical reactions which involve a radical pair with correlated spins (radical in a 'cage'). In the first part, the radical pair theory is described: mechanisms of singlet-triplet mixing, the different interactions inside the pair and a quantum mechanical treatment of the radical pair. The details of the experimental method (nanosecond laser flash photolysis) are reported in the second part. In the third part are shown experimental results obtained on Anthraquinone (AQ) - Hydrogen donors systems: - There is no magnetic field effect in homogeneous solution even at a high viscosity. The absorption spectra of the different reaction intermediates are obtained. - However a magnetic field effect is put forward when AQ is introduced in SDS micelles which are hydrogen donors. The absorption spectrum of the AQH · . semi-quinone radical in 'cage' is shown and a mechanism is proposed for its disappearance to generate the AQH-S and AQH 2 species. - The addition of 9, 10 Dihydroanthracene (DH2) inside the micelle near AQ induces an increase of the magnetic field effect by creation of (AQH · . - DH · . ) pairs which diffuse slowly. - Fixed radical pairs in a protein matrix were studied in reaction centers of photosynthetic bacteria: in that case, the half effect field is shifted to low fields when compared to the previously described systems. (author) [fr

Thermal-hydraulics stability of natural circulation BWR under startup. Flashing effects

International Nuclear Information System (INIS)

Hu, Rui; Kazimi, Mujid S.

2009-01-01

To help achieve the necessary natural circulation flow, a fairly long chimney is installed in a boiling natural circulation reactor like the ESBWR. In such systems, thermal-hydraulic stability during low pressure start-up should be examined while considering the flashing induced by the pressure drop in the channel and the chimney due to gravity head. In this work, a BWR stability analysis code in the frequency domain, named FISTAB (Flashing-Induced STability Analysis for BWR), was developed to address the issue of flashing-induced instability. A thermal-hydraulics non-homogeneous equilibrium model (NHEM) based on a drift flux formulation along with a lumped fuel dynamics model is incorporated in the work. The vapor generation rate is derived from the mixture energy conservation equation while considering the effect of flashing. The functionality of the FISTAB code was confirmed by comparison to experimental results from SIRIUS-N facility at CRIEPI, Japan. Both stationary and perturbation results agree well with the experimental results. (author)

The SWARF high energy flash X-ray facility

International Nuclear Information System (INIS)

Gilbert, J.F.; Dove, E.W.D.

1976-06-01

A description is presented of the SWARF flash radiography facility at AWRE Foulness, which is stated to be the most powerful flash x-ray system available, in the U.K. The machine consists essentially of a Marx generator, a coaxial Blumlein system and an x-ray tube. The voltage output from the Marx generator (about 2.5 MV from an 80 kV input) is applied to a large re-entrant Blumlein pulse-forming line. Near maximum voltage, an adjustable oil switch short-circuits one end of the Blumlein generator and so applies a square voltage pulse of 65 ns duration to the x-ray tube. The x-rays are produced from a tantalum target which forms the anode of a vacuum field emission diode. The facility consists of two field machines positioned so that radiographs can be obtained from different angles. The description is given under the following heads: modus operandi; constructional details; oil installation; electrical details; commissioning, calibration and electrical data; flash radiography in explosives research; operational control of facility, film packs; radiographic results; further developments; overall performance. (U.K.)

Flash pyrolysis, a process for utilizing contaminated wood; Flash-Pyrolyse - eine Moeglichkeit der stofflichen Verwertung von kontaminiertem Holz

Energy Technology Data Exchange (ETDEWEB)

Meier, D; Wehlte, S; Faix, O [Bundesforschungsanstalt fuer Forst- und Holzwirtschaft, Hamburg (Germany). Inst. fuer Holzchemie und Chemische Technologie des Holzes

1997-12-31

Flash pyrolysis of wood treated with common pesticides poses no technical probelms. Product yields, with a maximum oil yield at 475 C, are similar to those of untreated wood. Most of the heavy metals are retained by the coal while a small part aheres to the coal layer of the sand bed. The resulting pyrolysis oil contains neither chromium nor copper. (orig) [Deutsch] Die Flash-Pyrolyse der mit den gaengigsten Schutzmitteln behandelten Hoelzer bereitet verfahrenstechnisch keine Probleme. Auch die Produktausbeuten, mit einem oelmaximum bei 475 C, aehneln denen von naturbelassenem Holz. Der groesste Teil der Schwermetalle wurde an die Kohle gebunden, ein geringer Teil blieb auf der Kohleschicht des Sandes haften. Im Hauptprodukt Pyrolyseoel konnten weder Chrom noch Kupfer nachgewiesen werden. (orig)

Flash pyrolysis, a process for utilizing contaminated wood; Flash-Pyrolyse - eine Moeglichkeit der stofflichen Verwertung von kontaminiertem Holz

Energy Technology Data Exchange (ETDEWEB)

Meier, D.; Wehlte, S.; Faix, O. [Bundesforschungsanstalt fuer Forst- und Holzwirtschaft, Hamburg (Germany). Inst. fuer Holzchemie und Chemische Technologie des Holzes

1996-12-31

Flash pyrolysis of wood treated with common pesticides poses no technical probelms. Product yields, with a maximum oil yield at 475 C, are similar to those of untreated wood. Most of the heavy metals are retained by the coal while a small part aheres to the coal layer of the sand bed. The resulting pyrolysis oil contains neither chromium nor copper. (orig) [Deutsch] Die Flash-Pyrolyse der mit den gaengigsten Schutzmitteln behandelten Hoelzer bereitet verfahrenstechnisch keine Probleme. Auch die Produktausbeuten, mit einem oelmaximum bei 475 C, aehneln denen von naturbelassenem Holz. Der groesste Teil der Schwermetalle wurde an die Kohle gebunden, ein geringer Teil blieb auf der Kohleschicht des Sandes haften. Im Hauptprodukt Pyrolyseoel konnten weder Chrom noch Kupfer nachgewiesen werden. (orig)

Efficiencies and Physical Principles of Various Solar Energy Conversion Processes Leading to the Photolysis of Water

Energy Technology Data Exchange (ETDEWEB)

Bergene, T

1996-12-31

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

Nanosecond optical limiting response of sandwich-type neodymium dyphthalocyanine in a co-polymer host

NARCIS (Netherlands)

Aneeshkumar, B.N.; Gopinath, P.; Thomas, J.; Vallabhan, C.P.G.; Nampoori, V.P.N.; Radhakrishnan, P.

2004-01-01

The nanosecond optical limiting characteristics of sandwich-type neodymium diphthalocyanine in a co-polymer matrix of polymethyl methacrylate (PMMA) and methyl-2-cyanoacrylate have been studied for the first time. The measurements were performed using 9 ns laser pulses generated from a

Flash Points of Secondary Alcohol and n-Alkane Mixtures.

Science.gov (United States)

Esina, Zoya N; Miroshnikov, Alexander M; Korchuganova, Margarita R

2015-11-19

The flash point is one of the most important characteristics used to assess the ignition hazard of mixtures of flammable liquids. To determine the flash points of mixtures of secondary alcohols with n-alkanes, it is necessary to calculate the activity coefficients. In this paper, we use a model that allows us to obtain enthalpy of fusion and enthalpy of vaporization data of the pure components to calculate the liquid-solid equilibrium (LSE) and vapor-liquid equilibrium (VLE). Enthalpy of fusion and enthalpy of vaporization data of secondary alcohols in the literature are limited; thus, the prediction of these characteristics was performed using the method of thermodynamic similarity. Additionally, the empirical models provided the critical temperatures and boiling temperatures of the secondary alcohols. The modeled melting enthalpy and enthalpy of vaporization as well as the calculated LSE and VLE flash points were determined for the secondary alcohol and n-alkane mixtures.

Study of coal flash hydropyrolysis denitrogenation

Energy Technology Data Exchange (ETDEWEB)

Tang, Lihua; Zhu, Zibin; Zhu, Hongbin; Zhang, Chengfang [Research Institute of Inorganic Chemical Technology, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China)

2003-05-15

The hydrodenitrogenation efficiency of 14 types of coals and the reaction mechanism of Zalainouer coal were studied in an experimental entrained bed reactor by flash hydropyrolysis (FHP). The results showed that flash hydropyrolysis is an efficient method for denitrogenation, and that the denitrogenation percentage increases with an increase in temperature and hydrogen pressure. For example, the denitrogenation percentage can reach up to about 60% for Zalainouer coal at 700 C and 6.0 MPa hydrogen pressure. The denitrogenation efficiency of different coal types is related to H/C. According to the conclusion of the study, the denitrogenation percentage increases with the increase in H/C ratio, reaching about 12% when H/C is equal to 0.6, and 40-55% when H/C is above 1.0. The results indicate that FHP is an efficient technique for removing nitrogen in coal.

Development of a precipitation-area curve for warning criteria of short-duration flash flood

Science.gov (United States)

Bae, Deg-Hyo; Lee, Moon-Hwan; Moon, Sung-Keun

2018-01-01

This paper presents quantitative criteria for flash flood warning that can be used to rapidly assess flash flood occurrence based on only rainfall estimates. This study was conducted for 200 small mountainous sub-catchments of the Han River basin in South Korea because South Korea has recently suffered many flash flood events. The quantitative criteria are calculated based on flash flood guidance (FFG), which is defined as the depth of rainfall of a given duration required to cause frequent flooding (1-2-year return period) at the outlet of a small stream basin and is estimated using threshold runoff (TR) and antecedent soil moisture conditions in all sub-basins. The soil moisture conditions were estimated during the flooding season, i.e., July, August and September, over 7 years (2002-2009) using the Sejong University Rainfall Runoff (SURR) model. A ROC (receiver operating characteristic) analysis was used to obtain optimum rainfall values and a generalized precipitation-area (P-A) curve was developed for flash flood warning thresholds. The threshold function was derived as a P-A curve because the precipitation threshold with a short duration is more closely related to basin area than any other variables. For a brief description of the P-A curve, generalized thresholds for flash flood warnings can be suggested for rainfall rates of 42, 32 and 20 mm h-1 in sub-basins with areas of 22-40, 40-100 and > 100 km2, respectively. The proposed P-A curve was validated based on observed flash flood events in different sub-basins. Flash flood occurrences were captured for 9 out of 12 events. This result can be used instead of FFG to identify brief flash flood (less than 1 h), and it can provide warning information to decision-makers or citizens that is relatively simple, clear and immediate.

The effect of polymer type on electric breakdown strength on a nanosecond time scale

Institute of Scientific and Technical Information of China (English)

Zhao Liang; Su Jian-Cang; Pan Ya-Feng; Zhang Xi-Bo

2012-01-01

Based on the concepts of fast polarization,effective electric field and electron impact ionization criterion,the effect of polymer type on electric breakdown strength (EBD) on a nanosecond time scale is investigated,and a formula that qualitatively characterizes the relation between the electric breakdown strength and the polymer type is derived.According to this formula,it is found that the electric breakdown strength decreases with an increase in the effective relative dielectric constants of the polymers.By calculating the effective relative dielectric constants for different types of polymers,the theoretical relation for the electric breakdown strengths of common polymers is predicted.To verify the prediction,the polymers of PE (polyethylene),PTFE (polytetrafluoroethelene),PMMA (organic glass) and Nylon are tested with a nanosecond-pulse generator.The experimental result shows EBD (PTFE) ＞ EBD (PMMA) ＞ EBD (Nylon) ＞ EBD (PE).This result is consistent with the theoretical prediction.

An early warning system for flash floods in hyper-arid Egypt

Science.gov (United States)

Cools, J.; Vanderkimpen, P.; El Afandi, G.; Abdelkhalek, A.; Fockedey, S.; El Sammany, M.; Abdallah, G.; El Bihery, M.; Bauwens, W.; Huygens, M.

2012-02-01

An early warning system (EWS) for flash floods has been developed for part of the Sinai peninsula of Egypt, an hyper-arid area confronted with limited availability of field data, limited understanding of the response of the wadi to rainfall, and a lack of correspondence between rainfall data and observed flash flood events. This paper shows that an EWS is not a "mission impossible" when confronted with large technical and scientific uncertainties and limited data availability. Firstly, the EWS has been developed and tested based on the best available information, this being quantitative data (field measurements, simulations and remote sensing images) complemented with qualitative "expert opinion" and local stakeholders' knowledge. Secondly, a set of essential parameters has been identified to be estimated or measured under data-poor conditions. These are: (1) an inventory of past significant rainfall and flash flood events, (2) the spatial and temporal distribution of the rainfall events and (3) transmission and infiltration losses and (4) thresholds for issuing warnings. Over a period of 30 yr (1979-2010), only 20 significant rain events have been measured. Nine of these resulted in a flash flood. Five flash floods were caused by regional storms and four by local convective storms. The results for the 2010 flash flood show that 90% of the total rainfall volume was lost to infiltration and transmission losses. Finally, it is discussed that the effectiveness of an EWS is only partially determined by technological performance. A strong institutional capacity is equally important, especially skilled staff to operate and maintain the system and clear communication pathways and emergency procedures in case of an upcoming disaster.

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."

Flash floods warning technique based on wireless communication networks data

Science.gov (United States)

David, Noam; Alpert, Pinhas; Messer, Hagit

2010-05-01

Flash floods can occur throughout or subsequent to rainfall events, particularly in cases where the precipitation is of high-intensity. Unfortunately, each year these floods cause severe property damage and heavy casualties. At present, there are no sufficient real time flash flood warning facilities found to cope with this phenomenon. Here we show the tremendous potential of flash floods advanced warning based on precipitation measurements of commercial microwave links. As was recently shown, wireless communication networks supply high resolution precipitation measurements at ground level while often being situated in flood prone areas, covering large parts of these hazardous regions. We present the flash flood warning potential of the wireless communication system for two different cases when floods occurred at the Judean desert and at the northern Negev in Israel. In both cases, an advanced warning regarding the hazard could have been announced based on this system. • This research was supported by THE ISRAEL SCIENCE FOUNDATION (grant No. 173/08). This work was also supported by a grant from the Yeshaya Horowitz Association, Jerusalem. Additional support was given by the PROCEMA-BMBF project and by the GLOWA-JR BMBF project.

Tolfenamic acid degradation by direct photolysis and the UV-ABC/H2O2 process: factorial design, kinetics, identification of intermediates, and toxicity evaluation.

Science.gov (United States)

de Melo da Silva, Lucas; Pereira Cavalcante, Rodrigo; Fabbro Cunha, Rebeca; Gozzi, Fábio; Falcao Dantas, Renato; de Oliveira, Silvio Cesar; Machulek, Amilcar

2016-12-15

This study employed direct UV-ABC photolysis and the UV-ABC/H 2 O 2 process to investigate the degradation of tolfenamic acid (TA), a common anti-inflammatory drug used in both human and veterinary medicine. A 2 3 factorial design with added center point was used to evaluate the effect of three independent variables-namely, H 2 O 2 concentration ([H 2 O 2 ]), TA concentration ([TA]), and experiment time (time)-on TA degradation and H 2 O 2 photolysis during UV-ABC/H 2 O 2 treatment using a high-pressure mercury vapor lamp (photon flux of 2.6307 × 10 4 J s -1 ) as the UV irradiation source. The responses yielded similar values, revealing a linear behavior, with correlation coefficients R = 0.9968 and R adj = 0.9921 for TA degradation and R = 0.9828 and R adj = 0.9570 for H 2 O 2 photolysis. The most efficient combination of variables was [H 2 O 2 ] = 255 mg L -1 and [TA] = 25 mg L -1 , resulting in 100% TA degradation and 98.87% H 2 O 2 photolysis by 90 min of treatment. Additionally, the second-order kinetic constant of the reaction between TA and HO ● was determined using a competitive kinetic model, employing 2,4-dichlorophenoxyacetic acid (2,4D) as the reference compound. The kinetic constant was 1.9 × 10 10 M -1 s -1 in alkaline medium. TA degradation by direct photolysis generated quinone imines as by-products, responsible for the formation of a dark red "internal filter" that increased the value of acute toxicity to Artemia salina. The UV-ABC/H 2 O 2 process did not promote formation of quinone imines by 90 min of treatment and therefore did not increase acute toxicity values. Several by-products generated during TA degradation were identified and possible degradation pathways for the UV-ABC and UV-ABC/H 2 O 2 processes were proposed. Copyright © 2016 Elsevier B.V. All rights reserved.

The role of spin-orbit coupling in the photolysis of methylcobalamin

Energy Technology Data Exchange (ETDEWEB)

Andruniów, Tadeusz [Department of Chemistry, Advanced Materials Engineering and Modelling Group, Wroclaw University of Technology, 50-370 Wroclaw (Poland); Lodowski, Piotr; Jaworska, Maria [Department of Theoretical Chemistry, Institute of Chemistry, University of Silesia, Szkolna 9, PL-40 006 Katowice (Poland); Garabato, Brady D. [Department of Chemistry, University of Louisville, 2320 South Brook Street, Louisville, Kentucky 40292 (United States); Kozlowski, Pawel M., E-mail: pawel@louisville.edu [Department of Chemistry, University of Louisville, 2320 South Brook Street, Louisville, Kentucky 40292 (United States); Department of Food Sciences, Medical University of Gdansk, Al. Gen. J. Hallera 107, 80-416 Gdansk (Poland)

2016-03-28

The photolysis of the methylcobalamin cofactor (MeCbl) in its base-off form was investigated by considering the extent of spin-orbit coupling (SOC). Triplet Co–C photodissociation pathways previously invoked at the density functional theory level using Landau-Zener theory were further validated with ab initio calculations that combine SOC based on multi-state second order perturbation theory. It was determined that SOC is feasible between singlet and triplet states at elongated Co–C distances, leading to photodissociation from the state having dominant σ(d{sub z}{sup 2}) character, by either direct coupling with the lowest singlet states or by crossing with SOC mixed triplets.

Time Correlations of Lightning Flash Sequences in Thunderstorms Revealed by Fractal Analysis

Science.gov (United States)

Gou, Xueqiang; Chen, Mingli; Zhang, Guangshu

2018-01-01

By using the data of lightning detection and ranging system at the Kennedy Space Center, the temporal fractal and correlation of interevent time series of lightning flash sequences in thunderstorms have been investigated with Allan factor (AF), Fano factor (FF), and detrended fluctuation analysis (DFA) methods. AF, FF, and DFA methods are powerful tools to detect the time-scaling structures and correlations in point processes. Totally 40 thunderstorms with distinguishing features of a single-cell storm and apparent increase and decrease in the total flash rate were selected for the analysis. It is found that the time-scaling exponents for AF (αAF) and FF (αFF) analyses are 1.62 and 0.95 in average, respectively, indicating a strong time correlation of the lightning flash sequences. DFA analysis shows that there is a crossover phenomenon—a crossover timescale (τc) ranging from 54 to 195 s with an average of 114 s. The occurrence of a lightning flash in a thunderstorm behaves randomly at timescales τc but shows strong time correlation at scales >τc. Physically, these may imply that the establishment of an extensive strong electric field necessary for the occurrence of a lightning flash needs a timescale >τc, which behaves strongly time correlated. But the initiation of a lightning flash within a well-established extensive strong electric field may involve the heterogeneities of the electric field at a timescale τc, which behave randomly.

Quantitative assessment on the contribution of direct photolysis and radical oxidation in photochemical degradation of 4-chlorophenol and oxytetracycline.

Science.gov (United States)

Liu, Yiqing; He, Xuexiang; Fu, Yongsheng; Dionysiou, Dionysios D

2016-07-01

In UV-254 nm/H2O2 advanced oxidation process (AOP), the potential degradation pathways for organic pollutants include (1) hydrolysis, (2) direct H2O2 oxidation, (3) UV direct photolysis, and (4) hydroxyl radical (HO(•)) reaction. In this study, the contribution of these pathways was quantitatively assessed in the photochemical destruction of 4-chlorophenol (4-CP), demonstrating pathways (3) and (4) to be predominantly responsible for the removal of 4-CP by UV/H2O2 in 50 mM phosphate buffer solution. Increasing reaction pH could significantly enhance the contribution of direct photolysis in UV/H2O2 process. The contribution of HO(•) oxidation was improved with increasing initial H2O2 concentration probably due to the increased formation of HO(•). Presence of sodium carbonate (Na2CO3) as in UV/H2O2/Na2CO3 system promoted the degradation of 4-CP, with carbonate radical (CO3 (•-)) reaction and direct photolysis identified to be the main contributing pathways. The trends in the contribution of each factor were further evaluated and validated on the degradation of the antibiotic compound oxytetracycline (OTC). This study provides valuable information on the relative importance of different reaction pathways on the photochemical degradation of organic contaminants such as 4-CP and OTC in the presence and absence of a CO3 (•-) precursor.

Spin-on nanostructured silicon-silica film displaying room-temperature nanosecond lifetime photoluminescence

Energy Technology Data Exchange (ETDEWEB)

Cohen, Y.; Hatton, B.; Miguez, H.; Coombs, N.; Fournier-Bidoz, S.; Ozin, G.A. [Materials Chemistry Research Group, Department of Chemistry, Lash Miller Chemical Laboratories, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6 (Canada); Grey, J.K.; Beaulac, R.; Reber, C. [Department of Chemistry, University of Montreal, Montreal, Quebec H3C 3J7 (Canada)

2003-04-17

A yellow transparent mesoporous silica film has been achieved by the incorporation of silicon nanoclusters into its channels. The resulting nanocomposite - fabricated using a combination of evaporation induced self- assembly and chemical vapor deposition - emits light brightly at visible wavelengths and has nanosecond radiative lifetimes at room temperature when excited by ultraviolet light (see Figure). (Abstract Copyright [2003], Wiley Periodicals, Inc.)

Nanosecond Surface Microdischarges in Multilayer Structures

Science.gov (United States)

Dubinov, A. E.; Lyubimtseva, V. A.

2018-05-01

Multilayer structures in which nanosecond surface microdischarges are generated have been developed, fabricated, and investigated. In these structures, layers are made in the form of thin transparent films, and a plasma discharge channel is formed in thin spacings between the layers. Passage of the discharge channel from one layer into the neighboring layer is implemented via pre-fabricated microholes. Images of microdischarges were obtained which confirmed that their plasma channels are formed according to the route assigned by the holes. The route may follow a fairly complex scheme and have self-intersection points and portions in which the electrons are bound to move in opposition to the electric field. In studying the shape of channels in multilayer strictures, the authors have found a new physical effect which lies in the azimuthal self-orientation of the discharge channel as it passes from one microhole to another.

Flash Flood Type Identification within Catchments in Beijing Mountainous Area

Science.gov (United States)

Nan, W.

2017-12-01

Flash flood is a common type of disaster in mountainous area, Flash flood with the feature of large flow rate, strong flushing force, destructive power, has periodically caused loss to life and destruction to infrastructure in mountainous area. Beijing as China's political, economic and cultural center, the disaster prevention and control work in Beijing mountainous area has always been concerned widely. According to the transport mechanism, sediment concentration and density, the flash flood type identification within catchment can provide basis for making the hazards prevention and mitigation policy. Taking Beijing as the study area, this paper extracted parameters related to catchment morphological and topography features respectively. By using Bayes discriminant, Logistic regression and Random forest, the catchments in Beijing mountainous area were divided into water floods process, fluvial sediment transport process and debris flows process. The results found that Logistic regression analysis showed the highest accuracy, with the overall accuracy of 88.2%. Bayes discriminant and Random forest had poor prediction effects. This study confirmed the ability of morphological and topography features to identify flash flood process. The circularity ratio, elongation ratio and roughness index can be used to explain the flash flood types effectively, and the Melton ratio and elevation relief ratio also did a good job during the identification, whereas the drainage density seemed not to be an issue at this level of detail. Based on the analysis of spatial patterns of flash flood types, fluvial sediment transport process and debris flow process were the dominant hazards, while the pure water flood process was much less. The catchments dominated by fluvial sediment transport process were mainly distributed in the Yan Mountain region, where the fault belts were relatively dense. The debris flow process prone to occur in the Taihang Mountain region thanks to the abundant

System of ispFlash configuration

International Nuclear Information System (INIS)

Bourrion, Olivier

2003-01-01

The aim of this module is to allow the use of FPGA components instead of EPLD components which for an equivalent or even inferior capacity are more expensive. For instance, the idea is to replace CPLD components having 512 macro-cells by one FPGA spartan II of Xilinx. However, due to the configuration's volatility, one configuration means is needed to put under voltage. A solution appears to be the using of a high capacity Flash memory coupled to a CPLD of small size to comply with the FPGA configuration protocol; also, one has to provide an in situ configuration means for this memory. Obviously, a product having an equivalent functionality already exists, since Xilinx and ALTERA supply PROMs of serial configuration. Unfortunately, they are expensive and a dealer is implied while the FLASH, the small CPLD and the FPGA spartan II are currently available. In conclusion, by using this assembly, which requires a small supplementary surface and a delay of upmost 240 ms (for the largest FPGA 1 Mbit), one obtains a solution cheaper and more performing than an EPLD of high capacity

Nanosecond laser textured superhydrophobic metallic surfaces and their chemical sensing applications

Science.gov (United States)

Ta, Duong V.; Dunn, Andrew; Wasley, Thomas J.; Kay, Robert W.; Stringer, Jonathan; Smith, Patrick J.; Connaughton, Colm; Shephard, Jonathan D.

2015-12-01

This work demonstrates superhydrophobic behavior on nanosecond laser patterned copper and brass surfaces. Compared with ultrafast laser systems previously used for such texturing, infrared nanosecond fiber lasers offer a lower cost and more robust system combined with potentially much higher processing rates. The wettability of the textured surfaces develops from hydrophilicity to superhydrophobicity over time when exposed to ambient conditions. The change in the wetting property is attributed to the partial deoxidation of oxides on the surface induced during laser texturing. Textures exhibiting steady state contact angles of up to ∼152° with contact angle hysteresis of around 3-4° have been achieved. Interestingly, the superhydrobobic surfaces have the self-cleaning ability and have potential for chemical sensing applications. The principle of these novel chemical sensors is based on the change in contact angle with the concentration of methanol in a solution. To demonstrate the principle of operation of such a sensor, it is found that the contact angle of methanol solution on the superhydrophobic surfaces exponentially decays with increasing concentration. A significant reduction, of 128°, in contact angle on superhydrophobic brass is observed, which is one order of magnitude greater than that for the untreated surface (12°), when percent composition of methanol reaches to 28%.

The role of direct photolysis and indirect photochemistry in the environmental fate of ethylhexyl methoxy cinnamate (EHMC) in surface waters.

Science.gov (United States)

Vione, D; Calza, P; Galli, F; Fabbri, D; Santoro, V; Medana, C

2015-12-15

The aquatic environmental fate of ethylhexyl methoxy cinnamate (EHMC), one of the most used UVB filters worldwide, was studied by assessing its environmental persistence and photoinduced transformations. The role of direct and indirect photolysis was evaluated. Direct photolysis was shown to play a key role, and this process is expected to be the main attenuation route of EHMC in sunlit surface waters. In contrast, the reaction with OH radicals would be negligible and that with (3)CDOM* would at most be a secondary process. The measurement of the quantum yield of direct photolysis and of the rate constants of reaction with photogenerated transient species (or, sometimes, the use of reasonable values for the latter) allowed the prediction of the EHMC half-life time in surface waters, by means of a validated photochemical model. The predicted EHMC lifetime is of the order of hours to a few days in fair-weather summertime, and the main factors controlling the EHMC phototransformation in sunlit surface waters would be the water depth and the dissolved organic carbon (DOC) content. The formation of transformation products (TPs) was followed as well via HPLC/HRMS. Three TPs were detected in the samples exposed to UVA radiation, while one additional TP was detected in the samples exposed to UVB radiation. The detected TPs comprised 4-methoxybenzaldehyde, a hydroxylated derivative and dimeric species. Through the use of heterogeneous photocatalysis with TiO2, seven additional TPs were identified, most of them resulting from the further degradation of primary TPs formed through direct photolysis and that might be detected in aquatic systems as well. The photodegradation of EHMC in the presence of TiO2 yielded more toxic TPs than the parent compound (as determined with the Vibrio fischeri Microtox assay). The increased toxicity is partially accounted for by the formation of 4-methoxybenzaldehyde. Copyright © 2015 Elsevier B.V. All rights reserved.

IR Laser-Induced Thermolysis and UV Laser-Induced Photolysis of 1,3-Diethyldisiloxane: Chemical Vapour Deposition of Nanotextured Hydridoalkylsilicones

Czech Academy of Sciences Publication Activity Database

Urbanová, Markéta; Bastl, Zdeněk; Šubrt, Jan; Pola, Josef

2001-01-01

Roč. 11, č. 6 (2001), s. 1557-1562 ISSN 0959-9428 R&D Projects: GA AV ČR IAA4072806 Keywords : thermolysis * UV laser photolysis * composition Subject RIV: CH - Nuclear ; Quantum Chemistry Impact factor: 2.736, year: 2001

MR study of intracranial disease with three-dimensional FLASH

International Nuclear Information System (INIS)

Runge, V.M.; Wood, M.L.; Kaufman, D.M.; Nelson, K.L.; Traill, M.R.; Wolpert, S.M.

1987-01-01

A three-dimensional FLASH technique was used to study 36 patients with intracranial disease at 1 T (Siemens Magnetom). This included 15 cases of intracranial neoplastic disease, four with the application of intravenous Gd-DTPA. Contiguous thin sections (1-2 mm thick) were acquired of the entire intracranial contents using one acquisition (scan time of 5-15 minutes). A MIPRON (KONTRON Instruments) image processing work station was used for rapid image display and 3D reconstruction. 3D FLASH was found to be superior to spin-echo imaging at 1 T for the detection of hemorrhage. 3D acquisition also provided superior localization of neoplastic disease. The T1 contrast achieved was comparable to spin-echo technique with a repetition time/echo time of .6/17. The advantages in terms of lesion localization and thin-section imaging with high spatial resolution of the entire brain may lead to use of 3D FLASH in place of conventional spin-echo imaging

Plasma plume expansion dynamics in nanosecond Nd:YAG laserosteotome

Science.gov (United States)

Abbasi, Hamed; Rauter, Georg; Guzman, Raphael; Cattin, Philippe C.; Zam, Azhar

2018-02-01

In minimal invasive laser osteotomy precise information about the ablation process can be obtained with LIBS in order to avoid carbonization, or cutting of wrong types of tissue. Therefore, the collecting fiber for LIBS needs to be optimally placed in narrow cavities in the endoscope. To determine this optimal placement, the plasma plume expansion dynamics in ablation of bone tissue by the second harmonic of a nanosecond Nd:YAG laser at 532 nm has been studied. The laserinduced plasma plume was monitored in different time delays, from one nanosecond up to one hundred microseconds. Measurements were performed using high-speed gated illumination imaging. The expansion features were studied using illumination of the overall visible emission by using a gated intensified charged coupled device (ICCD). The camera was capable of having a minimum gate width (Optical FWHM) of 3 ns and the timing resolution (minimum temporal shift of the gate) of 10 ps. The imaging data were used to generate position-time data of the luminous plasma-front. Moreover, the velocity of the plasma plume expansion was studied based on the time-resolved intensity data. By knowing the plasma plume profile over time, the optimum position (axial distance from the laser spot) of the collecting fiber and optimal time delay (to have the best signal to noise ratio) in spatial-resolved and time-resolved laser-induced breakdown spectroscopy (LIBS) can be determined. Additionally, the function of plasma plume expansion could be used to study the shock wave of the plasma plume.

Deconstructing continuous flash suppression

OpenAIRE

Yang, Eunice; Blake, Randolph

2012-01-01

In this paper, we asked to what extent the depth of interocular suppression engendered by continuous flash suppression (CFS) varies depending on spatiotemporal properties of the suppressed stimulus and CFS suppressor. An answer to this question could have implications for interpreting the results in which CFS influences the processing of different categories of stimuli to different extents. In a series of experiments, we measured the selectivity and depth of suppression (i.e., elevation in co...

Coherent imaging at FLASH

International Nuclear Information System (INIS)

Chapman, H N; Bajt, S; Duesterer, S; Treusch, R; Barty, A; Benner, W H; Bogan, M J; Frank, M; Hau-Riege, S P; Woods, B W; Boutet, S; Cavalleri, A; Hajdu, J; Iwan, B; Seibert, M M; Timneanu, N; Marchesini, S; Sakdinawat, A; Sokolowski-Tinten, K

2009-01-01

We have carried out high-resolution single-pulse coherent diffractive imaging at the FLASH free-electron laser. The intense focused FEL pulse gives a high-resolution low-noise coherent diffraction pattern of an object before that object turns into a plasma and explodes. In particular we are developing imaging of biological specimens beyond conventional radiation damage resolution limits, developing imaging of ultrafast processes, and testing methods to characterize and perform single-particle imaging.

Undergraduate Separations Utilizing Flash Chromatography

Science.gov (United States)

Horowitz, G.

2000-02-01

This article describes the procedures used to carry out four flash chromatography experiments: the isolation of the carotenes, chlorophylls and xanthophylls from a spinach extract; the separation of ß-carotene from tetraphenyl cyclopentadienone; the isolation of (+) and (-) carvone from caraway and spearmint oil; and the purification of benzil from benzoin. Apparatus used is nonbreakable, easy to use, and inexpensive.

Determination of the photolysis rate coefficient of monochlorodimethyl sulfide (MClDMS) in the atmosphere and its implications for the enhancement of SO2 production from the DMS + Cl2 reaction.

Science.gov (United States)

Copeland, G; Lee, E P F; Williams, R G; Archibald, A T; Shallcross, D E; Dyke, J M

2014-01-01

In this work, the photolysis rate coefficient of CH3SCH2Cl (MClDMS) in the lower atmosphere has been determined and has been used in a marine boundary layer (MBL) box model to determine the enhancement of SO2 production arising from the reaction DMS + Cl2. Absorption cross sections measured in the 28000-34000 cm(-1) region have been used to determine photolysis rate coefficients of MClDMS in the troposphere at 10 solar zenith angles (SZAs). These have been used to determine the lifetimes of MClDMS in the troposphere. At 0° SZA, a photolysis lifetime of 3-4 h has been obtained. The results show that the photolysis lifetime of MClDMS is significantly smaller than the lifetimes with respect to reaction with OH (≈ 4.6 days) and with Cl atoms (≈ 1.2 days). It has also been shown, using experimentally derived dissociation energies with supporting quantum-chemical calculations, that the dominant photodissocation route of MClDMS is dissociation of the C-S bond to give CH3S and CH2Cl. MBL box modeling calculations show that buildup of MClDMS at night from the Cl2 + DMS reaction leads to enhanced SO2 production during the day. The extra SO2 arises from photolysis of MClDMS to give CH3S and CH2Cl, followed by subsequent oxidation of CH3S.

Large-volume excitation of air, argon, nitrogen and combustible mixtures by thermal jets produced by nanosecond spark discharges

Science.gov (United States)

Stepanyan, Sergey; Hayashi, Jun; Salmon, Arthur; Stancu, Gabi D.; Laux, Christophe O.

2017-04-01

This work presents experimental observations of strong expanding thermal jets following the application of nanosecond spark discharges. These jets propagate in a toroidal shape perpendicular to the interelectrode axis, with high velocities of up to 30 m s-1 and over distances of the order of a cm. Their propagation length is much larger than the thermal expansion region produced by the conventional millisecond sparks used in car engine ignition, thus greatly improving the volumetric excitation of gas mixtures. The shape and velocity of the jets is found to be fairly insensitive to the shape of the electrodes. In addition, their spatial extent is found to increase with the number of nanosecond sparks and with the discharge voltage, and to decrease slightly with the pressure between 1 and 7 atm at constant applied voltage. Finally, this thermal jet phenomenon is observed in experiments conducted with many types of gas mixtures, including air, nitrogen, argon, and combustible CH4/air mixtures. This makes nanosecond repetitively pulsed discharges particularly attractive for aerodynamic flow control or plasma-assisted combustion because of their ability to excite large volumes of gas, typically about 100 times the volume of the discharge.

Damage caused by a nanosecond UV laser on a heated copper surface

Energy Technology Data Exchange (ETDEWEB)

Henč-Bartolić, V., E-mail: visnja.henc@fer.hr [University of Zagreb, Faculty of Electrical Engineering and Computing, Unska 3, 10000 Zagreb (Croatia); Bončina, T. [University of Maribor, Faculty of Mechanical Engineering, Smetanova 17, 2000 Maribor (Slovenia); Jakovljević, S., E-mail: suzana.jakovljevic@fsb.hr [University of Zagreb, Faculty of Mechanical Engineering and Naval Architecture, Ivana Lučića 5, 10002 Zagreb (Croatia); Panjan, P. [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Zupanič, F. [University of Maribor, Faculty of Mechanical Engineering, Smetanova 17, 2000 Maribor (Slovenia)

2016-08-15

Highlights: • A Cu-plate was exposed to nanosecond UV laser with max. energy 1.1 J/cm{sup 2}. • Surface topography was studied on the cold and heated copper plate. • At room temperature, a crater formed, the melt was ejected from it. • Capillary waves formed in the vicinity of the crater at 360 °C. - Abstract: This work studied the effect of thin copper plate temperature on its surface morphology after irradiation using a pulsed nanosecond UV laser. The surface characteristics were investigated using scanning electron microscopy, energy dispersive X-ray spectroscopy, focused ion beam and stylus profilometry. When a target was at room temperature, a crater and the radial flow of molten Cu from the crater was observed. When the thin target was warm (about 360 °C ± 20 °C), a crater was smaller, and quasi-semicircular waves with the periodicity of around 3 μm appeared in its vicinity. The origin of the waves is Marangoni effect, causing thermocapillary waves, which in same occasions had a structure of final states of chaos in Rayleigh–Bénard convection.

Are UV photolysis and UV/H2O2 process efficient to treat estrogens in waters? Chemical and biological assessment at pilot scale.

Science.gov (United States)

Cédat, Bruno; de Brauer, Christine; Métivier, Hélène; Dumont, Nathalie; Tutundjan, Renaud

2016-09-01

In this study, UV based treatments were implemented at pilot scale to assess their ability to remove hormones from treated wastewater, especially with the view to equip small and medium size Wastewater Treatment Plants (WTPs). To this end, the degradation of a mixture of estrogenic hormones (Estrone (E1), β-Estradiol (E2), and 17α-Ethinyl Estradiol (EE2)) in waters by UV photolysis and UV/H2O2 process was investigated in real conditions. A particular attention was paid at designing a well validated laboratory scale pilot in order to optimise oxidant concentrations and UV fluence. A Low pressure lamp (254 nm) was used in a flow through commercial reactor. The effects of water matrices (drinking water and treated wastewater) and H2O2 concentrations (10, 40, and 90 mg/L) on the pilot efficiency were first determined. Only E1 could be partially degraded by UV photolysis whereas hormones were all well removed by UV/H2O2 process in both matrices. The second part of the study focused on a chemical and biological assessment of UV photolysis and UV/H2O2 process (30 and 50 mg/L). Degradation rate constants of hormones as well as changes in estrogenic activity (YES bioassay) and toxicity (Vibrio fischeri) were followed at the same time. UV photolysis could not remove neither estrogens nor estrogenic activity at relevant UV fluence in waters. However 80% of initial estrogenic compounds and estrogenic activity could be removed from treated wastewater by combining UV fluence of 423 and 520 mJ/cm(2) with 50 and 30 mg/L of H2O2, respectively. No high estrogenic or toxic by-products were detected by the two bioassays following UV photolysis or UV/H2O2 process. Operating costs were estimated for a full scale pilot. H2O2 was the major cost. By combining the appropriate concentration of H2O2 and UV fluence, it could be possible to design a cost effective treatment for treating estrogens in small and medium size WTPs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Conformational detection of p53's oligomeric state by FlAsH Fluorescence.