Science.gov

Sample records for flashing jet studies

  1. General review of flashing jet studies.

    PubMed

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

    2010-01-15

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

  2. Shaped Charge Jet Flash Radiograph Digitization

    DTIC Science & Technology

    2005-09-01

    radiograph digitization of shaped chare jets provides warhead designers with the data required for empirically based models , as well as the jet...characterization used for comparison with high rate continuum modeling . Reduced digitization results include jet tip velocity, jet accumulated length...using CALCOMP model 9500 digitizing tablet. It has the resolution of 0.25 x 10-3 in., accuracy of ± 0.003 in. and about 6 ft in length. The digitized

  3. Flash Rust & Waterjetting Study

    SciTech Connect

    DORSH, P.M..

    2001-11-14

    Certain areas of the primary wall in the AY-101 tank annulus are being cleaned with a remotely operated waterjet. There is some concern on how it will effect the surface of the tank wall after cleaning and how to prevent rust and corrosion from developing on the wall in the future. This study addresses the cause and effects of flash rust, which typically develops on steel surfaces after the waterjetting process.

  4. A simple confined impingement jets mixer for flash nanoprecipitation.

    PubMed

    Han, Jing; Zhu, Zhengxi; Qian, Haitao; Wohl, Adam R; Beaman, Charles J; Hoye, Thomas R; Macosko, Christopher W

    2012-10-01

    Johnson and Prud'homme (2003. AICHE J 49:2264-2282) introduced the confined impingement jets (CIJ) mixer to prepare nanoparticles loaded with hydrophobic compounds (e.g., drugs, inks, fragrances, or pheromones) via flash nanoprecipitation (FNP). We have modified the original CIJ design to allow hand operation, eliminating the need for a syringe pump, and we added a second antisolvent dilution stage. Impingement mixing requires equal flow momentum from two opposing jets, one containing the drug in organic solvent and the other containing an antisolvent, typically water. The subsequent dilution step in the new design allows rapid quenching with high antisolvent concentration that enhances nanoparticle stability. This new CIJ with dilution (CIJ-D) mixer is a simple, cheap, and efficient device to produce nanoparticles. We have made 55 nm diameter β-carotene nanoparticles using the CIJ-D mixer. They are stable and reproducible in terms of particle size and distribution. We have also compared the performance of our CIJ-D mixer with the vortex mixer, which can operate at unequal flow rates (Liu et al., 2008. Chem Eng Sci 63:2829-2842), to make β-carotene-containing particles over a series of turbulent conditions. On the basis of dynamic light scattering measurements, the new CIJ-D mixer produces stable particles of a size similar to the vortex mixer. Our CIJ-D design requires less volume and provides an easily operated and inexpensive tool to produce nanoparticles via FNP and to evaluate new nanoparticle formulation.

  5. 450mm wafer patterning with jet and flash imprint lithography

    NASA Astrophysics Data System (ADS)

    Thompson, Ecron; Hellebrekers, Paul; Hofemann, Paul; LaBrake, Dwayne L.; Resnick, Douglas J.; Sreenivasan, S. V.

    2013-09-01

    The next step in the evolution of wafer size is 450mm. Any transition in sizing is an enormous task that must account for fabrication space, environmental health and safety concerns, wafer standards, metrology capability, individual process module development and device integration. For 450mm, an aggressive goal of 2018 has been set, with pilot line operation as early as 2016. To address these goals, consortiums have been formed to establish the infrastructure necessary to the transition, with a focus on the development of both process and metrology tools. Central to any process module development, which includes deposition, etch and chemical mechanical polishing is the lithography tool. In order to address the need for early learning and advance process module development, Molecular Imprints Inc. has provided the industry with the first advanced lithography platform, the Imprio® 450, capable of patterning a full 450mm wafer. The Imprio 450 was accepted by Intel at the end of 2012 and is now being used to support the 450mm wafer process development demands as part of a multi-year wafer services contract to facilitate the semiconductor industry's transition to lower cost 450mm wafer production. The Imprio 450 uses a Jet and Flash Imprint Lithography (J-FILTM) process that employs drop dispensing of UV curable resists to assist high resolution patterning for subsequent dry etch pattern transfer. The technology is actively being used to develop solutions for markets including NAND Flash memory, patterned media for hard disk drives and displays. This paper reviews the recent performance of the J-FIL technology (including overlay, throughput and defectivity), mask development improvements provided by Dai Nippon Printing, and the application of the technology to a 450mm lithography platform.

  6. FLASH SPECTROSCOPY AND FLASH FLUORIMETRY IN PHOTOSYNTHETIC STUDIES

    DTIC Science & Technology

    A comparative study of the flash induced forma tion of a pigment , X, absorbing at 515 millimicron in different classes of algae was made. This...that it occurs as a non- photosynthetic inter mediate, specifically as a consequence of damag ing photo-oxidation processes was examined. The latter

  7. Flash!

    NASA Astrophysics Data System (ADS)

    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.

  8. Flash Point and Chemical Composition of Aviation Kerosene (Jet A). Revision

    DTIC Science & Technology

    2000-05-26

    fuel flash point. In response to these recommen- dations, the FAA (FAA, 1997) has asked the aviation industry (through the Aviation Regulatory Action...source. The petroleum industry and fuel safety analysts often rely on the measured flash point to rank the explosion hazards of different fuels. The...affect the flashpoint significantly. Our experience with storing Jet A is consistent with industry experience (Batts and Fathoni, 1991) with long term

  9. A study of lightning flashes attending periods of banded snowfall

    NASA Astrophysics Data System (ADS)

    Market, Patrick S.; Becker, Amy E.

    2009-01-01

    Lightning flashes (N = 1088) associated with 24 thundersnow events in the central United States were analyzed to document flash polarity, signal strength, and multiplicity. Negative lightning flashes (N = 872; 80%) dominated positive flashes (N = 216; 20%) with wintry precipitation in this study, which stands in contrast to the majority of the research done on winter thunderstorms (primarily in Japan). Otherwise, limited work has been done, although thundersnow has been documented in the mid-latitudes of North America, Europe and Asia. Statistics on peak amplitude were determined for negative (positive) flashes, yielding mean and standard deviation values of -24 kA +/- 22 kA (+38 kA +/- 34 kA). A subset of winter lightning events (N = 16) were then sought that occurred with banded (single or multiple) snowfall, as banding often denotes greater organization in the atmosphere (e.g., a jet streak aloft to aid in ascent, or a low level jet streak to aid with moisture and thermal transport) and thus the potential for deeper snow totals. Radar reflectivity values were recorded at the location of each lightning flash, as well as the maximum radar reflectivity within the associated snow band. The location of the lightning activity within the snow band was also noted as being either leading edge (LE), trailing edge (TE), core (C), or not correlated (NC), with respect to the motion of the parent band. The majority of lightning flashes were found downstream of areas of highest radar reflectivity with respect to the motion of the snow bands, and not with the highest reflectivity values. If one uses the highest reflectivity values in a snowband as a proxy for the greatest surface snowfall intensity, then the ground terminus of a cloud-to-ground lightning (CG) flash is often not co-located with the heaviest snowfall rates. However, the work completed here does place the location of the typical CG flash ~15 km downstream of the snowband location, so one could use the occurrence

  10. Improved separation method for highly purified lutein from Chlorella powder using jet mill and flash column chromatography on silica gel.

    PubMed

    Shibata, Shinya; Ishihara, Chiyoko; Matsumoto, Keisuke

    2004-10-06

    We investigated an improved method for the separation of high-purified lutein from a commercially available spray-dried Chlorella powder (CP) using fine grinding by jet mill and flash column chromatography on a silica gel. Saponification and extraction of lutein were enhanced 2.3-2.9-fold in jet mill-treated CP (mean particle size, 20 microm) as compared to untreated CP (mean particle size, 67 microm). The carotenoid extract was dissolved in ether-hexane (1:1 v/v) and subjected to flash column chromatography on silica gel. A mixture of alpha- and beta-carotene was eluted with hexane, followed by elution with hexane-acetone-chloroform (7:2:1 v/v). Lutein (dark-orange band) was collected after the elution of an unknown colorless compound (detected based on UV absorbance). The purity of lutein in this fraction was over 99%, and the yield was 60%. The present study provides key information for obtaining highly purified lutein using flash column chromatography on a silica gel.

  11. Daily Physical Activity and Hot Flashes in the Study of Women's Health Across the Nation FLASHES Study

    PubMed Central

    Gibson, Carolyn; Matthews, Karen; Thurston, Rebecca

    2014-01-01

    Objective To examine the role of physical activity in menopausal hot flashes. Competing models conceptualize physical activity as a risk or protective factor for hot flashes. Few studies have examined this relationship prospectively using physiologic measures of hot flashes and physical activity. Design Over two 48 hour-periods, 51 participants wore a physiologic hot flash monitor and activity monitor, and reported their hot flashes in an electronic diary. Physiologic hot flashes, reported hot flashes and reported hot flashes without physiological corroboration were related to activity changes using hierarchical generalized linear modeling, adjusting for potential confounders. Setting Community. Patients Midlife women. Interventions None. Main Outcome Measures Physiologically-detected hot flashes and reported hot flashes with and without physiologic corroboration. Results Hot flash reports without physiologic corroboration were more likely after activity increases (OR 1.04, 95% CI: 1.00-1.10, p=.01), particularly among women with higher levels of depressive symptoms (interaction p=.02). No other types of hot flashes were related to physical activity. Conclusion Acute increases in physical activity were associated with increased reporting of hot flashes lacking physiologic corroboration, particularly among women with depressive symptoms. Clinicians should consider the role of symptom perception and reporting in relations between physical activity and hot flashes. PMID:24491454

  12. Defect reduction of high-density full-field patterns in jet and flash imprint lithography

    NASA Astrophysics Data System (ADS)

    Singh, Lovejeet; Luo, Kang; Ye, Zhengmao; Xu, Frank; Haase, Gaddi; Curran, David; LaBrake, Dwayne; Resnick, Douglas; Sreenivasan, S. V.

    2011-04-01

    Imprint lithography has been shown to be an effective technique for replication of nano-scale features. Jet and Flash Imprint Lithography (J-FIL) involves the field-by-field deposition and exposure of a low viscosity resist deposited by jetting technology onto the substrate. The patterned mask is lowered into the fluid which then quickly flows into the relief patterns in the mask by capillary action. Following this filling step, the resist is crosslinked under UV radiation, and then the mask is removed leaving a patterned resist on the substrate. Acceptance of imprint lithography for manufacturing will require demonstration that it can attain defect levels commensurate with the defect specifications of high end memory devices. Typical defectivity targets are on the order of 0.10/cm2. This work summarizes the results of defect inspections focusing on two key defect types; random non-fill defects occurring during the resist filling process and repeater defects caused by interactions with particles on the substrate. Non-fill defectivity must always be considered within the context of process throughput. The key limiting throughput step in an imprint process is resist filling time. As a result, it is critical to characterize the filling process by measuring non-fill defectivity as a function of fill time. Repeater defects typically have two main sources; mask defects and particle related defects. Previous studies have indicated that soft particles tend to cause non-repeating defects. Hard particles, on the other hand, can cause either resist plugging or mask damage. In this work, an Imprio 500 twenty wafer per hour (wph) development tool was used to study both defect types. By carefully controlling the volume of inkjetted resist, optimizing the drop pattern and controlling the resist fluid front during spreading, fill times of 1.5 seconds were achieved with non-fill defect levels of approximately 1.2/cm2. Longevity runs were used to study repeater defects and a nickel

  13. Sweeping Jet Optimization Studies

    NASA Technical Reports Server (NTRS)

    Melton, LaTunia Pack; Koklu, Mehti; Andino, Marlyn; Lin, John C.; Edelman, Louis

    2016-01-01

    Progress on experimental efforts to optimize sweeping jet actuators for active flow control (AFC) applications with large adverse pressure gradients is reported. Three sweeping jet actuator configurations, with the same orifice size but di?erent internal geometries, were installed on the flap shoulder of an unswept, NACA 0015 semi-span wing to investigate how the output produced by a sweeping jet interacts with the separated flow and the mechanisms by which the flow separation is controlled. For this experiment, the flow separation was generated by deflecting the wing's 30% chord trailing edge flap to produce an adverse pressure gradient. Steady and unsteady pressure data, Particle Image Velocimetry data, and force and moment data were acquired to assess the performance of the three actuator configurations. The actuator with the largest jet deflection angle, at the pressure ratios investigated, was the most efficient at controlling flow separation on the flap of the model. Oil flow visualization studies revealed that the flow field controlled by the sweeping jets was more three-dimensional than expected. The results presented also show that the actuator spacing was appropriate for the pressure ratios examined.

  14. Photonic Flash Sintering of Ink-Jet-Printed Back Electrodes for Organic Photovoltaic Applications.

    PubMed

    Polino, Giuseppina; Shanmugam, Santhosh; Bex, Guy J P; Abbel, Robert; Brunetti, Francesca; Di Carlo, Aldo; Andriessen, Ronn; Galagan, Yulia

    2016-01-27

    A study of the photonic flash sintering of a silver nanoparticle ink printed as the back electrode for organic solar cells is presented. A number of sintering settings with different intensities and pulse durations have been tested on both full-area and grid-based silver electrodes, using the complete emission spectrum of the flash lamps from UV-A to NIR. However, none of these settings was able to produce functional devices with performances comparable to those of reference cells prepared using thermally sintered ink. Different degradation mechanisms were detected in the devices with a flash-sintered back electrode. The P3HT:PCBM photoactive layer appears to be highly heat-sensitive and turned out to be severely damaged by the high temperatures generated in the silver layer during the sintering. In addition, UV-induced photochemical degradation of the functional materials was identified as another possible source of performance deterioration in the devices with grid-based electrodes. Reducing the light intensity does not provide a proper solution because in this case the Ag electrode is not sintered sufficiently. For both types of devices, with full-area and grid-based electrodes, these problems could be solved by excluding the short wavelength contribution from the flash light spectrum using a filter. Optimized sintering parameters allowed manufacture of OPV devices with performance equal to those of the reference devices. Photonic flash sintering of the top electrode in organic solar cells was demonstrated for the first time. It reveals the great potential of this sintering method for the future roll-to-roll manufacturing of organic solar cells from solution.

  15. Using the LMA to Study Flash Initiation

    NASA Astrophysics Data System (ADS)

    Harlin, J. D.; Hamlin, T.; Krehbiel, P. R.; Thomas, R. J.; Rison, W.

    2001-12-01

    In support of the Severe Thunderstorm Electrification and Precipitation Study (STEPS 2000), New Mexico Tech's Lightning Mapping Array (LMA) was dispersed over an 80 km wide area of eastern Colorado and western Kansas from early May to mid August of 2000. Operating 13 stations, with real time communications, enabled us to locate and record all lightning activity within 200 km of the array. Because of the LMA's unique 3-D resolution, it is possible to observe individual lightning flashes and compare the initial radiation sources of both intra-cloud and cloud to ground discharges. Comparing the localization, timing, and power of the initial sources can reveal specific traits within a storm, enabling us to categorize storms. Differences in flash initiation could be indicative of the differences in the local environment. Some of the physical characteristics of the storm can be determined by comparing the LMA points to radar scans, electric field measurements, and other observations. Of particular interest are bi-polar pulses, which emit very powerful radiation compared to other sources. Some of these pulses have been observed to be the first source in a lightning discharge, while others have been found to be isolated both spatially and temporally. Only certain storms produce these energetic events, most storms do not. A small selection of these bi-polar events have been confirmed using electric field data, but were misidentified as positive cloud to grounds by the NLDN.

  16. Flash photolysis-shock tube studies

    SciTech Connect

    Michael, J.V.

    1993-12-01

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

  17. Collimated Jet Or Expanding Outflow: Possible Origins of GRBs And X-Ray Flashes

    SciTech Connect

    Mizuta, Akira; Yamasaki, Tatsuya; Nagataki, Shigehiro; Mineshige, Shin; /Kyoto U., Yukawa Inst., Kyoto

    2006-08-10

    We investigate the dynamics of an injected outflow propagating in a progenitor in the context of the collapsar model for gamma-ray bursts (GRBs) through two dimensional axisymmetric relativistic hydrodynamic simulations. Initially, we locally inject an outflow near the center of a progenitor. We calculate 25 models, in total, by fixing its total input energy to be 10{sup 51} ergs s{sup -1} and radius of the injected outflow to be 7 x 10{sup 7} cm while varying its bulk Lorentz factor, {Lambda}{sub 0} = 1.05 {approx} 5, and its specific internal energy, {epsilon}{sub 0}/c{sup 2} 30 (with c being speed of light). The injected outflow propagates in the progenitor and drives a large-scale outflow or jet. We find a smooth but dramatic transition from a collimated jet to an expanding outflow among calculated models. The opening angle of the outflow ({theta}{sub sim}) is sensitive to {Lambda}{sub 0}; we find {theta}{sub sim} < 2{sup o} for {Lambda}{sub 0} {approx}> 3. The maximum Lorentz factor is, on the other hand, sensitive to both of {Lambda}{sub 0} and {epsilon}{sub 0}; roughly {Lambda}{sub max} {approx} {Lambda}{sub 0}(1 + {epsilon}{sub 0}/c{sup 2}). In particular, a very high Lorentz factor of {Lambda}{sub max} {approx}> 100 is achieved in one model. A variety of opening angles can arise by changing {epsilon}{sub 0}, even when the maximum Lorentz factor is fixed. The jet structure totally depends on {Lambda}{sub 0}. When {Lambda}{sub 0} is high, a strong bow shock appears and generates a back flow. High pressure progenitor gas heated by the bow shock collimates the outflow to form a narrow, relativistic jet. A number of internal oblique shocks within the jet are generated by the presence of the back flow and/or shear instability. When {Lambda}{sub 0} is low, on the contrary, the outflow expands soon after the injection, since the bow shock is weak and thus the pressure of the progenitor gas is not high enough to confine the flow. Our finding will explain a smooth

  18. Jet and flash imprint defectivity: assessment and reduction for semiconductor applications

    NASA Astrophysics Data System (ADS)

    Malloy, Matt; Litt, Lloyd C.; Johnson, Steve; Resnick, Douglas J.; Lovell, David

    2011-04-01

    Defectivity has been historically identified as a leading technical roadblock to the implementation of nanoimprint lithography for semiconductor high volume manufacturing. The lack of confidence in nanoimprint's ability to meet defect requirements originates in part from the industry's past experiences with 1X lithography and the shortage in end-user generated defect data. SEMATECH has therefore initiated a defect assessment aimed at addressing these concerns. The goal is to determine whether nanoimprint, specifically Jet and Flash Imprint Lithography from Molecular Imprints, is capable of meeting semiconductor industry defect requirements. At this time, several cycles of learning have been completed in SEMATECH's defect assessment, with promising results. J-FIL process random defectivity of < 0.1 def/cm2 has been demonstrated using a 120nm half-pitch template, providing proof of concept that a low defect nanoimprint process is possible. Template defectivity has also improved significantly as shown by a pre-production grade template at 80nm pitch. Cycles of learning continue on feature sizes down to 22nm.

  19. Assessment of the flash-lamp photon-cleaning detritiation method tested at JET

    NASA Astrophysics Data System (ADS)

    Bekris, N.; Coad, J. P.; Widdowson, A.; Erbe, A.; Ehrmann, J.; Kloppe, B.; JET-EFDA Contributors

    2009-06-01

    Flash-lamp photonic cleaning has been tested in situ and at the Beryllium Handling Facility (BeHF) at JET. Two adjacent number 4 divertor tiles have been exposed to numerous pulses up to the nominal energy of 500 J. Starting the photon-cleaning process with tile G4A and using energies up to 350 J did not appear to be efficient for detritiation. Consequently, the untreated tile G4B has been treated at the maximum energy of 500 J. Combustion measurements confirmed that the photon-cleaning was partly efficient as about 74% of the initial tritium concentration has been released. The average tritium concentration on the surface of the tile after treatment was 2.45 × 10 8 Bq/cm 3 which is only four times lower than the initial activity. However, it is remarkable to notice that the bulk activity of the tiles remains constant indicating that during the detritiation treatment there is no tritium diffusing into the bulk of the tile.

  20. High throughput Jet and Flash Imprint Lithography for semiconductor memory applications

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Fletcher, Brian; Thompson, Ecron; Liu, Weijun; Stachowiak, Tim; Khusnatdinov, Niyaz; Irving, J. W.; Longsine, Whitney; Traub, Matthew; Truskett, Van; LaBrake, Dwayne; Ye, Zhengmao

    2016-03-01

    Imprint lithography has been shown to be an effective technique for replication of nano-scale features. Jet and Flash* Imprint Lithography (J-FIL*) involves the field-by-field deposition and exposure of a low viscosity resist deposited by jetting technology onto the substrate. The patterned mask is lowered into the fluid which then quickly flows into the relief patterns in the mask by capillary action. Following this filling step, the resist is crosslinked under UV radiation, and then the mask is removed, leaving a patterned resist on the substrate. There are two critical components to meeting throughput requirements for imprint lithography. Using a similar approach to what is already done for many deposition and etch processes, imprint stations can be clustered to enhance throughput. The FPA-1200NZ2C is a four station cluster system designed for high volume manufacturing. For a single station, throughput includes overhead, resist dispense, resist fill time (or spread time), exposure and separation. Resist exposure time and mask/wafer separation are well understood processing steps with typical durations on the order of 0.10 to 0.20 seconds. To achieve a total process throughput of 15 wafers per hour (wph) for a single station, it is necessary to complete the fluid fill step in 1.5 seconds. For a throughput of 20 wph, fill time must be reduced to only one second. There are several parameters that can impact resist filling. Key parameters include resist drop volume (smaller is better), system controls (which address drop spreading after jetting), Design for Imprint or DFI (to accelerate drop spreading) and material engineering (to promote wetting between the resist and underlying adhesion layer). In addition, it is mandatory to maintain fast filling, even for edge field imprinting. In this paper, we address the improvements made in all of these parameters to enable a 1.50 second filling process for a sub-20nm device like pattern and have demonstrated this capability

  1. Multiple jet study

    NASA Technical Reports Server (NTRS)

    Walker, R. E.; Kors, D. L.

    1973-01-01

    Test data is presented which allows determination of jet penetration and mixing of multiple cold air jets into a ducted subsonic heated mainstream flow. Jet-to-mainstream momentum flux ratios ranged from 6 to 60. Temperature profile data is presented at various duct locations up to 24 orifice diameters downstream of the plane of jet injection. Except for two configurations, all geometries investigated had a single row of constant diameter orifices located transverse to the main flow direction. Orifice size and spacing between orifices were varied. Both of these were found to have a significant effect on jet penetration and mixing. The best mixing of the hot and cold streams was achieved with duct height.

  2. A flash photographic method for droplet impingement studies

    SciTech Connect

    Hart, V.

    1999-07-01

    This paper describes an experimental method to visualize the impingement process of a liquid droplet onto a solid surface with sufficient clarity to reveal fine details of the droplet surface structure and rim jet produced during the impingement process. The method incorporates a 35 mm SLR camera with bellows, motor drive, macro lens, backlighting by a short duration flash lamp, diffusers and a commercially available timing control unit to trigger the flash. Results using the experimental arrangement are demonstrated for a water droplet striking a horizontal surface at a velocity of about 1 m/s, though the photographic method may be applied to any other condition and liquid. A series of photographs are presented that show the repeatability of the impingement process, image clarity, surface structure of the droplet during impingement.

  3. Flash X-Ray Studies Of Ballistic Phenomena

    NASA Astrophysics Data System (ADS)

    Webster, Edwin A.

    1983-03-01

    Frankford Arsenal was a pioneer in the development and application of flash radiography of ballistic phenomena. Frankford Arsenal first began using the Westinghouse Micronex flash X-ray system in 1941, and converted to Field Emission Corporation (now Hewlett-Packard) flash X-ray equipment in the early 1960's. When Frankford Arsenal closed in 1977, its missions and equipment were transferred to U.S. Army Armament Research and Development Command. The flash X-ray studies performed at Frankford Arsenal are now being continued at the ARRADCOM Test Site, Fort Dix, New Jersey as well as at ARRADCOM Headquarters, Dover, New Jersey. These studies are concerned with investigations of small caliber ammunition and weapons, and reduced scale models of large caliber projectiles. The important feature of flash X-rays in ballistics research and development is that high speed radiographs provide qualitative and quantitative information which frequently cannot be obtained by any other means or which can be obtained more easily and inexpensively by this technique. This paper describes some of the experimental applications of high speed radiography in obtaining data on various ballistic phenomena such as the determination of projectile penetration of armor plate, and particle size and orientation after penetration.

  4. A Study of Small EUV Flashes around Coronal Hole Boundaries

    NASA Astrophysics Data System (ADS)

    Boucheron, Laura E.; Valluri, Meghala; McAteer, James

    2016-05-01

    Coronal holes (CHs) are theorized to have magnetically open magnetic flux lines and are the source of high-speed solar wind. It is hypothesized that there will be small scale reconnection events at the CH boundary due to interaction between open fields of the CH and closed fields of the quiet and active sun. These reconnection events are expected to manifest themselves as spatially small and temporally short increases in extreme ultraviolet intensity at the CH boundary. We investigate an automated detection of small flashes near the CH boundary and present statistics on the characteristics of these flashes, including lifetime, size, and brightness. We compare these characteristics to those of flashes occurring away from the CH boundary. The application of active contours without edges (ACWE) allows for the automated detection of CHs without dependence on a fixed threshold value. ACWE employs an energy-minimization in which CHs are assumed to have more homogeneous intensities than surrounding active and quiet Sun. The CHs segmented with ACWE tend to correspond to unipolar magnetic regions, are consistent with concurrent solar wind observations, and qualitatively match the coronal holes segmented by other methods. Detection of flashes around the CH boundary serve as additional evidence of correct CH segmentation and provides further evidence supporting the hypothesis of reconnection events at CH boundaries, while the ACWE now provides a tool to study these flashes further in large datasets.

  5. Rectangular subsonic jet flowfield study

    NASA Technical Reports Server (NTRS)

    Morrison, Gerald L.; Tatterson, Gary B.; Swan, David H.

    1987-01-01

    The flowfield of a rectangular jet with 2:1 aspect ratio was studied at an axial Reynolds number of 127,000, using a three-dimensional laser anemometer. The flowfield surveys resulted in mean velocity vector field plots and contour plots of the Reynolds stress tensor components for the major and minor axes. These data contribute substantially to currently available data of jet flowfields.

  6. Studying white dwarf merger remnants with FLASH

    NASA Astrophysics Data System (ADS)

    Jenks, Malia

    2017-01-01

    There is still uncertainty as to the progenitor systems of type Ia supernova (SN Ia). Both single and double degenerate systems have been suggested as progenitors. In a double degenerate system a merger between the two white dwarfs, with total mass at or exceeding the Chandrasekhar mass, leads to the supernova. If the explosion occurs during the merging process it is a violent merger. If an explosion doesn't occur while the stars merge the system becomes a white dwarf of unstable mass. For mergers of this type with differing starting masses it has been shown that during the viscous evolution carbon burning starts far from the center and stably converts the star to oxygen and neon. In this case the star will eventually collapse to a neutron star and not produce an SN Ia. The case of similar mass mergers has been much less explored. Using the results of a smooth particle hydrodynamic merger we simulate the viscous evolution of models of different mass ratios with FLASH. These simulations test if a similar mass merger can lead to an SN Ia, and begin to probe where the transition from similar to dissimilar mass occurs.

  7. Laboratory studies of volcanic jets

    NASA Astrophysics Data System (ADS)

    Kieffer, Susan Werner; Sturtevant, Bradford

    1984-09-01

    The study of the fluid dynamics of violent volcanic eruptions by laboratory experiment is described, and the important fluid-dynamic processes that can be examined in laboratory models are discussed in detail. In preliminary experiments, pure gases are erupted from small reservoirs. The gases used are Freon 12 and Freon 22, two gases of high molecular weight and high density that are good analogs of heavy and particulate-laden volcanic gases; nitrogen, a moderate molecular weight, moderate density gas for which the thermodynamic properties are well known; and helium, a low molecular weight, lowdensity gas that is used as a basis for comparison with the behavior of the heavier gases and as an analog of steam, the gas that dominates many volcanic eruptions. Transient jets erupt from the reservoir into the laboratory upon rupture of a thin diaphragm at the exit of a convergent nozzle. The gas accelerates from rest in the reservoir to high velocity in the jet. Reservoir pressures and geometries are such that the fluid velocity in the jets is initially supersonic and later decays to subsonic. The measured reservoir pressure decreases as the fluid expands through repetitively reflecting rarefaction waves, but for the conditions of these experiments, a simple steady-discharge model is sufficient to explain the pressure decay and to predict the duration of the flow. Density variations in the flow field have been visualized with schlieren and shadowgraph photography. The observed structure of the jet is correlated with the measured pressure history. The starting vortex generated when the diaphragm ruptures becomes the head of the jet. Though the exit velocity is sonic, the flow head in the helium jet decelerates to about one-third of sonic velocity in the first few nozzle diameters, the nitrogen head decelerates to about three-fourths of sonic velocity, while Freon maintains nearly sonic velocity. The impulsive acceleration of reservoir fluid into the surrounding atmosphere

  8. A study of thunderstorm microphysical properties and lightning flash counts associated with terrestrial gamma-ray flashes

    NASA Astrophysics Data System (ADS)

    Barnes, D. E.; Splitt, M. E.; Dwyer, J. R.; Lazarus, S.; Smith, D. M.; Rassoul, H. K.

    2015-04-01

    The terrestrial gamma ray flash (TGF) is an emission of highly energetic radiation produced by or at least in close association with lightning. Previous investigations attempted to isolate the production mechanisms and production altitude(s) of TGFs as well as macrophysical characteristics, while thunderstorm microphysical characteristics were largely ignored. This investigation into thunderstorms and their hydrometeor and flash characteristics utilize temporal and spatial coincident satellite passes between the Reuven Ramaty High Energy Solar Spectroscopic Imager and the Tropical Rainfall Measuring Mission to determine the bulk (or footprint) microphysical properties of two types of study events, the thunderstorm complexes which are associated with TGFs (TGF case) and the thunderstorm complexes which did not produce a TGF detected by Reuven Ramaty High Energy Solar Spectroscopic Imager during the pass (non-TGF case). Results are presented for two different comparison methods. The first case utilizes geographic region weighted by TGF distribution, and the second is based on TGF percentage of occurrence when compared to total flash count of data set. Results show that the associated storms around the TGF location possess differences in the hydrometeor concentrations: cloud liquid water, cloud ice, precipitation water, and precipitation ice. These results take place at different levels of the atmosphere, including the mixed phase region. Additionally, results will show that TGFs are a consistent percentage of observed flashes as the rate of TGFs as a function of Lightning Imaging Sensor flash count is relatively constant.

  9. Behavioral Weight Loss for the Management of Menopausal Hot Flashes: A Pilot Study

    PubMed Central

    Thurston, Rebecca C.; Ewing, Linda J.; Low, Carissa A.; Christie, Aimee J.; Levine, Michele D.

    2014-01-01

    Objective Although adiposity has been considered protective against hot flashes, newer data suggest positive relations between flashes and adiposity. No studies have been specifically designed to test whether weight loss reduces hot flashes. This pilot study aimed to evaluate the feasibility, acceptability, and initial efficacy of behavioral weight loss to reduce hot flashes. Methods Forty overweight/obese women with hot flashes (≥4/day) were randomized to a behavioral weight loss intervention or to wait list control. Hot flashes were assessed pre- and post-intervention via physiologic monitor, diary, and questionnaire. Comparisons of changes in hot flashes and anthropometrics between conditions were tested via Wilcoxon tests. Results Study retention (83%) and intervention satisfaction (93.8%) were high. Most women (74.1%) reported that hot flash reduction was a main motivator to lose weight. Women randomized to the weight loss intervention lost more weight (-8.86 kg) than did women randomized to control (+0.23 kg, p<.0001). Women randomized to weight loss also showed greater reductions in questionnaire-reported hot flashes (2-week hot flashes: −63.0) than did women in the control (−28.0, p=.03), a difference not demonstrated in other hot flash measures. Reductions in weight and hot flashes were significantly correlated (e.g., r=.47, p=.006). Conclusions This pilot study showed a behavioral weight loss program to be feasible, acceptable, and effective in producing weight loss among overweight/obese women with hot flashes. Findings indicate the importance of a larger study designed to test behavioral weight loss for hot flash reduction. Hot flash management could motivate women to engage in this health-promoting behavior. PMID:24977456

  10. Flash X-Ray Injector Study

    SciTech Connect

    Paul, A C

    2004-03-26

    The study described in this report1 models the FXR injector from the cathode to the exit of the injector. The calculations are compared to actual experimental measurements, table 1. In these measurements the anode voltage was varied by changing the Marks-Bank charging voltage. The anode-cathode spacing was varied by adjusting the location of the cathode in hopes of finding an island of minimum emittance (none found). The bucking coil current was set for zero field on the cathode. In these measurements, a pepper-pot mask was inserted into FXR at beam bug 135 and viewed downstream via a wiggle probe diagnostic at cell gap J21, figure 1. The observed expansion of the beamlets passing through the mask of known geometric layout and hole size allow a calculation of the phase space beam properties.

  11. Hypnotic relaxation therapy for treatment of hot flashes following prostate cancer surgery: a case study.

    PubMed

    Elkins, Gary R; Kendrick, Cassie; Koep, Lauren

    2014-01-01

    This case study reports on a 69-year-old African American male who presented with hot flashes following a diagnosis of prostate cancer and subsequent prostatectomy. Measures include both self-reported and physiologically measured hot flash frequency and sleep quality. The intervention involved 7 weekly sessions of hypnotic relaxation therapy directed toward alleviation of hot flashes. Posttreatment self-reported hot flashes decreased 94%; physiologically measured hot flashes decreased 100%; and sleep quality improved 87.5%. At week 12, both self-reported and physiologically measured hot flashes decreased 95% and sleep quality improved 37.5% over baseline, suggesting hypnotic relaxation therapy may be an effective intervention for men with hot flashes following treatment for prostate cancer.

  12. Jets.

    PubMed

    Rhines, Peter B.

    1994-06-01

    This is a discussion of concentrated large-scale flows in planetary atmospheres and oceans, argued from the viewpoint of basic geophysical fluid dynamics. We give several elementary examples in which these flows form jets on rotating spheres. Jet formation occurs under a variety of circumstances: when flows driven by external stress have a rigid boundary which can balance the Coriolis force, and at which further concentration can be caused by the beta effect; when there are singular lines like the line of vanishing windstress or windstress-curl, or the Equator; when compact sources of momentum, heat or mass radiate jet-like beta plumes along latitude circles; when random external stirring of the fluid becomes organized by the beta effect into jets; when internal instability of the mass field generates zonal flow which then is concentrated into jets; when bottom topographic obstacles radiate jets, and when frontogenesis leads to shallow jet formation. Essential to the process of jet formation in stratified fluids is the baroclinic life cycle described in geostrophic turbulence studies; there, conversion from potential to kinetic energy generates eddy motions, and these convert to quasibarotropic motions which then radiate and induce jet-like large-scale circulation. Ideas of potential vorticity stirring by eddies generalize the notion of Rossby-wave radiation, showing how jets embedded in an ambient potential vorticity gradient (typically due to the spherical geometry of the rotating planet) gain eastward momentum while promoting broader, weaker westward circulation. Homogenization of potential vorticity is an important limit point, which many geophysical circulations achieve. This well-mixed state is found in subdomains of the terrestrial midlatitude oceans, the high-latitude circumpolar ocean, and episodically in the middle atmosphere. Homogenization expels potential vorticity gradients vertically to the top and bottom of the fluid, and sideways to the edges of

  13. An observational and numerical study of a flash flood event in Eastern Marmara Region.

    NASA Astrophysics Data System (ADS)

    Kahraman, A.

    2010-09-01

    Warm season cut-off cyclones over North-western Anatolia frequently triggers storms with heavy precipitation over Marmara and Western Black Sea Region. Since the area is highly urbanized with a deficiency in substructure, an important percentage of these storms result in flash floods, producing severe damage and fatalities. A heavy precipitation case from 5th to 9th of June, 2010 is studied. With the large scale circulation of the cut-off low, the storm system over Northern Anatolia moved Black Sea, and after getting richer in moisture, turned back to land over Eastern Marmara Region resulting more than 100 mm of precipitation in 24 hours. A peak of 77 mm in 6 hours is observed at Istanbul Sabiha Gokcen Airport on 7th of June, 2010. Damage in some buildings and one death occured related with the flash flood. In addition to synoptic charts, satellite data, surface and upper air observations, numerical simulation with WRF-ARW is used to make a mesoscale analysis of the meteorological conditions. Heavy rain ingredients such as conditionally unstability, low level jet and high moisture exist over the region according to the model output. Precipitable water and storm relative helicity values are mature and CAPE is moderate.

  14. Study of J /ψ Production in Jets

    NASA Astrophysics Data System (ADS)

    Aaij, R.; Adeva, B.; Adinolfi, M.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Andreassi, G.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Archilli, F.; d'Argent, P.; Arnau Romeu, J.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Babuschkin, I.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baker, S.; Balagura, V.; Baldini, W.; Baranov, A.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Baryshnikov, F.; Baszczyk, M.; Batozskaya, V.; Batsukh, B.; Battista, V.; Bay, A.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Beiter, A.; Bel, L. J.; Bellee, V.; Belloli, N.; Belous, K.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Beranek, S.; Berezhnoy, A.; Bernet, R.; Bertolin, A.; Betancourt, C.; Betti, F.; Bettler, M.-O.; van Beuzekom, M.; Bezshyiko, Ia.; Bifani, S.; Billoir, P.; Bird, T.; Birnkraut, A.; Bitadze, A.; Bizzeti, A.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Boettcher, T.; Bondar, A.; Bondar, N.; Bonivento, W.; Bordyuzhin, I.; Borgheresi, A.; Borghi, S.; Borisyak, M.; Borsato, M.; Bossu, F.; Boubdir, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Braun, S.; Britsch, M.; Britton, T.; Brodzicka, J.; Buchanan, E.; Burr, C.; Bursche, A.; Buytaert, J.; Cadeddu, S.; Calabrese, R.; Calvi, M.; Calvo Gomez, M.; Camboni, A.; Campana, P.; Campora Perez, D. H.; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carson, L.; Carvalho Akiba, K.; Casse, G.; Cassina, L.; Castillo Garcia, L.; Cattaneo, M.; Cavallero, G.; Cenci, R.; Chamont, D.; Charles, M.; Charpentier, Ph.; Chatzikonstantinidis, G.; Chefdeville, M.; Chen, S.; Cheung, S.-F.; Chobanova, V.; Chrzaszcz, M.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cogoni, V.; Cojocariu, L.; Collazuol, G.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombs, G.; Coquereau, S.; Corti, G.; Corvo, M.; Costa Sobral, C. M.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Crocombe, A.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; Da Cunha Marinho, F.; Dall'Occo, E.; Dalseno, J.; David, P. N. Y.; Davis, A.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Serio, M.; De Simone, P.; Dean, C. T.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Demmer, M.; Dendek, A.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Dijkstra, H.; Dordei, F.; Dorigo, M.; Dosil Suárez, A.; Dovbnya, A.; Dreimanis, K.; Dufour, L.; Dujany, G.; Dungs, K.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Déléage, N.; Easo, S.; Ebert, M.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Falabella, A.; Farley, N.; Farry, S.; Fay, R.; Fazzini, D.; Ferguson, D.; Fernandez, G.; Fernandez Prieto, A.; Ferrari, F.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fini, R. A.; Fiore, M.; Fiorini, M.; Firlej, M.; Fitzpatrick, C.; Fiutowski, T.; Fleuret, F.; Fohl, K.; Fontana, M.; Fontanelli, F.; Forshaw, D. C.; Forty, R.; Franco Lima, V.; Frank, M.; Frei, C.; Fu, J.; Funk, W.; Furfaro, E.; Färber, C.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Gao, Y.; Garcia Martin, L. M.; García Pardiñas, J.; Garra Tico, J.; Garrido, L.; Garsed, P. J.; Gascon, D.; Gaspar, C.; Gavardi, L.; Gazzoni, G.; Gerick, D.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gianı, S.; Gibson, V.; Girard, O. G.; Giubega, L.; Gizdov, K.; Gligorov, V. V.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gorelov, I. V.; Gotti, C.; Govorkova, E.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graverini, E.; Graziani, G.; Grecu, A.; Greim, R.; Griffith, P.; Grillo, L.; Gruberg Cazon, B. R.; Grünberg, O.; Gushchin, E.; Guz, Yu.; Gys, T.; Göbel, C.; Hadavizadeh, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hamilton, B.; Han, X.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; Hatch, M.; He, J.; Head, T.; Heister, A.; Hennessy, K.; Henrard, P.; Henry, L.; van Herwijnen, E.; Heß, M.; Hicheur, A.; Hill, D.; Hombach, C.; Hopchev, H.; Hulsbergen, W.; Humair, T.; Hushchyn, M.; Hutchcroft, D.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jaeger, A.; Jalocha, J.; Jans, E.; Jawahery, A.; Jiang, F.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kandybei, S.; Karacson, M.; Kariuki, J. M.; Karodia, S.; Kecke, M.; Kelsey, M.; Kenzie, M.; Ketel, T.; Khairullin, E.; Khanji, B.; Khurewathanakul, C.; Kirn, T.; Klaver, S.; Klimaszewski, K.; Klimkovich, T.; Koliiev, S.; Kolpin, M.; Komarov, I.; Koppenburg, P.; Kosmyntseva, A.; Kozachuk, A.; Kozeiha, M.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krokovny, P.; Kruse, F.; Krzemien, W.; Kucewicz, W.; Kucharczyk, M.; Kudryavtsev, V.; Kuonen, A. K.; Kurek, K.; Kvaratskheliya, T.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lanfranchi, G.; Langenbruch, C.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Leflat, A.; Lefrançois, J.; Lefèvre, R.; Lemaitre, F.; Lemos Cid, E.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, T.; Li, Y.; Likhomanenko, T.; Lindner, R.; Linn, C.; Lionetto, F.; Liu, X.; Loh, D.; Longstaff, I.; Lopes, J. H.; Lucchesi, D.; Lucio Martinez, M.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Lusiani, A.; Lyu, X.; Machefert, F.; Maciuc, F.; Maev, O.; Maguire, K.; Malde, S.; Malinin, A.; Maltsev, T.; Manca, G.; Mancinelli, G.; Manning, P.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marinangeli, M.; Marino, P.; Marks, J.; Martellotti, G.; Martin, M.; Martinelli, M.; Martinez Santos, D.; Martinez Vidal, F.; Martins Tostes, D.; Massacrier, L. M.; Massafferri, A.; Matev, R.; Mathad, A.; Mathe, Z.; Matteuzzi, C.; Mauri, A.; Maurice, E.; Maurin, B.; Mazurov, A.; McCann, M.; McNab, A.; McNulty, R.; Meadows, B.; Meier, F.; Meissner, M.; Melnychuk, D.; Merk, M.; Merli, A.; Michielin, E.; Milanes, D. A.; Minard, M.-N.; Mitzel, D. S.; Mogini, A.; Molina Rodriguez, J.; Monroy, I. A.; Monteil, S.; Morandin, M.; Morawski, P.; Mordà, A.; Morello, M. J.; Morgunova, O.; Moron, J.; Morris, A. B.; Mountain, R.; Muheim, F.; Mulder, M.; Mussini, M.; Müller, D.; Müller, J.; Müller, K.; Müller, V.; Naik, P.; Nakada, T.; Nandakumar, R.; Nandi, A.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen, T. D.; Nguyen-Mau, C.; Nieswand, S.; Niet, R.; Nikitin, N.; Nikodem, T.; Nogay, A.; Novoselov, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Ogilvy, S.; Okhrimenko, O.; Oldeman, R.; Onderwater, C. J. G.; Otalora Goicochea, J. M.; Otto, A.; Owen, P.; Oyanguren, A.; Pais, P. R.; Palano, A.; Palutan, M.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Parker, W.; Parkes, C.; Passaleva, G.; Pastore, A.; Patel, G. D.; Patel, M.; Patrignani, C.; Pearce, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perret, P.; Pescatore, L.; Petridis, K.; Petrolini, A.; Petrov, A.; Petruzzo, M.; Picatoste Olloqui, E.; Pietrzyk, B.; Pikies, M.; Pinci, D.; Pistone, A.; Piucci, A.; Placinta, V.; Playfer, S.; Plo Casasus, M.; Poikela, T.; Polci, F.; Poluektov, A.; Polyakov, I.; Polycarpo, E.; Pomery, G. J.; Ponce, S.; Popov, A.; Popov, D.; Popovici, B.; Poslavskii, S.; Potterat, C.; Price, E.; Price, J. D.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Puig Navarro, A.; Punzi, G.; Qian, W.; Quagliani, R.; Rachwal, B.; Rademacker, J. H.; Rama, M.; Ramos Pernas, M.; Rangel, M. S.; Raniuk, I.; Ratnikov, F.; Raven, G.; Redi, F.; Reichert, S.; dos Reis, A. C.; Remon Alepuz, C.; Renaudin, V.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Rives Molina, V.; Robbe, P.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Lopez, J. A.; Rodriguez Perez, P.; Rogozhnikov, A.; Roiser, S.; Rollings, A.; Romanovskiy, V.; Romero Vidal, A.; Ronayne, J. W.; Rotondo, M.; Rudolph, M. S.; Ruf, T.; Ruiz Valls, P.; Saborido Silva, J. J.; Sadykhov, E.; Sagidova, N.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Gonzalo, D.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santimaria, M.; Santovetti, E.; Sarti, A.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schael, S.; Schellenberg, M.; Schiller, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmelzer, T.; Schmidt, B.; Schneider, O.; Schopper, A.; Schreiner, H. F.; Schubert, K.; Schubiger, M.; Schune, M.-H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Sergi, A.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Siddi, B. G.; Silva Coutinho, R.; Silva de Oliveira, L.; Simi, G.; Simone, S.; Sirendi, M.; Skidmore, N.; Skwarnicki, T.; Smith, E.; Smith, I. T.; Smith, J.; Smith, M.; Soares Lavra, l.; Sokoloff, M. D.; Soler, F. J. P.; Souza De Paula, B.; Spaan, B.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Stefko, P.; Stefkova, S.; Steinkamp, O.; Stemmle, S.; Stenyakin, O.; Stevens, H.; Stevenson, S.; Stoica, S.; Stone, S.; Storaci, B.; Stracka, S.; Stramaglia, M. E.; Straticiuc, M.; Straumann, U.; Sun, L.; Sutcliffe, W.; Swientek, K.; Syropoulos, V.; Szczekowski, M.; Szumlak, T.; T'Jampens, S.; Tayduganov, A.; Tekampe, T.; Tellarini, G.; Teubert, F.; Thomas, E.; van Tilburg, J.; Tilley, M. J.; Tisserand, V.; Tobin, M.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Toriello, F.; Tournefier, E.; Tourneur, S.; Trabelsi, K.; Traill, M.; Tran, M. T.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tully, A.; Tuning, N.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagnoni, V.; Valassi, A.; Valat, S.; Valenti, G.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vecchi, S.; van Veghel, M.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Venkateswaran, A.; Vernet, M.; Vesterinen, M.; Viana Barbosa, J. V.; Viaud, B.; Vieira, D.; Vieites Diaz, M.; Viemann, H.; Vilasis-Cardona, X.; Vitti, M.; Volkov, V.; Vollhardt, A.; Voneki, B.; Vorobyev, A.; Vorobyev, V.; Voß, C.; de Vries, J. A.; Vázquez Sierra, C.; Waldi, R.; Wallace, C.; Wallace, R.; Walsh, J.; Wang, J.; Ward, D. R.; Wark, H. M.; Watson, N. K.; Websdale, D.; Weiden, A.; Whitehead, M.; Wicht, J.; Wilkinson, G.; Wilkinson, M.; Williams, M.; Williams, M. P.; Williams, M.; Williams, T.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wraight, K.; Wyllie, K.; Xie, Y.; Xing, Z.; Xu, Z.; Yang, Z.; Yao, Y.; Yin, H.; Yu, J.; Yuan, X.; Yushchenko, O.; Zarebski, K. A.; Zavertyaev, M.; Zhang, L.; Zhang, Y.; Zhang, Y.; Zhelezov, A.; Zheng, Y.; Zhu, X.; Zhukov, V.; Zucchelli, S.; LHCb Collaboration

    2017-05-01

    The production of J /ψ mesons in jets is studied in the forward region of proton-proton collisions using data collected with the LHCb detector at a center-of-mass energy of 13 TeV. The fraction of the jet transverse momentum carried by the J /ψ meson, z (J /ψ ) ≡pT(J /ψ )/pT(jet ) , is measured using jets with pT(jet )>20 GeV in the pseudorapidity range 2.5 <η (jet )<4.0 . The observed z (J /ψ ) distribution for J /ψ mesons produced in b -hadron decays is consistent with expectations. However, the results for prompt J /ψ production do not agree with predictions based on fixed-order nonrelativistic QCD. This is the first measurement of the pT fraction carried by prompt J /ψ mesons in jets at any experiment.

  15. Living together flash-floods: the Versilia (Italy) case study

    NASA Astrophysics Data System (ADS)

    Caporali, Enrica; Pileggi, Tiziana; Gruntfest, Eve; Ruin, Isabelle; Federici, Giorgio

    2010-05-01

    The phenomena involved in extreme flash-flood events are complex and their prediction is affected by a given degree of uncertainty that makes the warning communication very difficult to achieve. The promotion of the natural hazards perception and the improvement in warning communication, aimed at human life losses reduction, became extremely important to accomplish. As a case study the Versilia river basin, in North - West Tuscany, Central Italy, prone to frequent flash-flood events, is considered. In the area, as stated from Santini (a local historian of XIX century), since 1386 existed special statutes, imposing rivers maintenance for protection against floods. Historical data testify also that the biggest flood events have occurred in the years 1774, 1885, 1902 and 1996. The last event is the one deeply analyzed and better documented. It was exceptional, the consequences on the population were dramatic, and the effects on building and infrastructures were catastrophic. With reference to the Versilia region, a geographic database for flood risk assessment, integrating diachronic data with the results of hydrological and sedimentological modeling, and integrating different competencies, is implemented. The purpose is to provide valuable aid to flash-floods prediction, risk assessment, structural and non-structural mitigation measures. As a first attempt, the combination of all the information available on the history of floods of Versilia region and model results, together with human exposure to flash-flood risk, is also explored. The aim is to investigate the detailed hydrometeorological circumstances that lead to accidental casualties and to better understand the predominant physical factors of risk. In the framework of enhancing natural hazards perception, a very particular educational experience, dedicated to the personnel that work on the territory with different roles and in different fields (i.e. municipal and provincial police, national forest body

  16. Metabolic Activity in the Insular Cortex and Hypothalamus Predicts Hot Flashes: An FDG-PET Study

    PubMed Central

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

    2012-01-01

    Context: 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. Objective: The aim of the study was to understand whether neurobiological factors predict hot flashes. Design: [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. Outcome Measures: We measured regional cerebral metabolic rate of glucose uptake (rCMRglu) in the insula and hypothalamus on FDG-PET. Results: 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. Conclusions: Trait neurobiological characteristics predict hot flashes. Genetic variability in CYP2D6 may underlie the neurobiological predisposition to hot flashes induced by AET. PMID:22723326

  17. Combat aircraft jet engine noise studies

    NASA Astrophysics Data System (ADS)

    Lewy, S.; Fournier, G.; Pianko, M.

    1992-04-01

    Methods of noise prediction and attenuation based on results obtained in civil applications are presented. Input data for directivity and radiation forecasts are given by measurements of vane and blade pressure fluctuations and by modal analysis of the spinning waves propagating in the inlet duct. Attention is given to sound generation mechanisms for subsonic and supersonic single jets and bypass jets. Prediction methods, based on Lighthill's equation (tensor due to the turbulence), are discussed, and the various means of jet noise reduction are reviewed. The CEPRA 19 anechoic wind tunnel, which is primarily designed for studying the jet noise radiated in the far field with flight effects is described.

  18. Combat aircraft jet engine noise studies

    NASA Astrophysics Data System (ADS)

    Lewy, S.; Fournier, G.; Pianko, M.

    Methods of noise prediction and attenuation, based on results obtained in civil applications are presented. Input data for directivity and radiation forecasts are given by measurements of vane and blade pressure fluctuations, and by modal analysis of the spinning waves propagating in the inlet duct. Attention is given to sound generation mechanisms for subsonic and supersonic single jets and bypass jets. Prediction methods, based on Lighthill's equation (tensor due to the turbulence), are discussed, and the various means of jet noise reduction are reviewed. The CEPRA 19 anechoic wind tunnel, which is primarily designed for studying the jet noise radiated in the far field with flight effects is described.

  19. Flash radiography studies with microcolumnar CsI

    NASA Astrophysics Data System (ADS)

    Smalley, Duane; Lutz, Steve; Baker, Stuart A.; Morgan, Dane V.; Brown, Kristina K.; Corredor, Andrew; Castaneda, Jesus J.; Phillips, David H.; Smith, Andrew S.

    2016-09-01

    There is growing interest in using low-energy flash x-ray sources in radiographic applications to provide high-contrast images of low-density objects. Due to the low-energy nature of the detected photons, thin bright scintillators are desired. In order to pursue an optimum radiographic system, experimental studies have been performed of the static imaging properties of thin microcolumnar CsI using a Platts x-ray source. The Platts source is a nominally 300 keV endpoint rod pinch diode x-ray source with a 35 ns pulse time. The source was used to measure the imaging properties of microcolumnar CsI with various thicknesses and backings. The experimental setup was modeled in GEANT4, and the images were simulated to estimate system performance. Taking into account the source photon production, radiation transport, and system optical performance, an accurate assessment of the detection system can be deduced.

  20. Numerical and experimental study of the dynamics of a superheated jet

    NASA Astrophysics Data System (ADS)

    Sinha, Avick; Gopalakrishnan, Shivasubramanian; Balasubramanian, Sridhar

    2015-11-01

    Flash-boiling is a phenomenon where a liquid experiences low pressures in a system resulting in it getting superheated. The sudden drop in pressures results in accelerated expansion and violent vapour formation. Understanding the physics behind the jet disintegration and flash-boiling phenomenon is still an open problem, with applications in automotive and aerospace combustors. The behaviour of a flash-boiling jet is highly dependent on the input parameters, inlet temperature and pressure. In the present study, the external (outside nozzle) and the internal (inside nozzle) flow characteristics of the two-phase flow has been studied numerically and experimentally. The phase change from liquid to vapour takes place over a finite period of time, modeled sing Homogeneous Relaxation Model (HRM). In order to validate the numerical results, controlled experiments were performed. Optical diagnostic techniques such as Particle Image Velocimetry (PIV) and Shadowgraphy were used to study the flow characteristics. Spray angle, penetration depth, droplet spectra were obtained which provides a better understanding of the break-up mechanism. Linear stability analysis is performed to study the stability characteristics of the jet.

  1. CYTOGENETIC STUDIES IN MICE TREATED WITH THE JET FUELS, JET-A AND JP-8

    EPA Science Inventory

    Cytogenetic studies in mice treated with the jet fuels, Jet-A and JP-8
    Abstract
    The genotoxic potential of the jet fuels, Jet-A and JP-8, were examined in mice treated on the skin with a single dose of 240 ug/mouse. Peripheral blood smears were prepared at the start of the ...

  2. CYTOGENETIC STUDIES IN MICE TREATED WITH THE JET FUELS, JET-A AND JP-8

    EPA Science Inventory

    Cytogenetic studies in mice treated with the jet fuels, Jet-A and JP-8
    Abstract
    The genotoxic potential of the jet fuels, Jet-A and JP-8, were examined in mice treated on the skin with a single dose of 240 ug/mouse. Peripheral blood smears were prepared at the start of the ...

  3. Paullinia cupana for control of hot flashes in breast cancer patients: a pilot study

    PubMed Central

    Oliveira, Saulo Silva; del Giglio, Adriana Braz; Lerner, Tatiana Goberstein; Zanellato, Rebecca Melo; Tiemi, Livia; Reifur, Lucas; Santi, Patrícia Xavier; del Giglio, Auro

    2013-01-01

    ABSTRACT Objective: To evaluated whether Paullinia cupana decrease number and severity of hot flashes in breast cancer survivors. Methods: This was a prospective phase II pilot study. We studied female breast cancer survivors who had completed the cancer treatment 3 months previously and who were experiencing at least 14 hot flashes per week. At least 9 of the 15 patients were required to have a decrease of at least 50% in hot flash severity score in keeping with the Simon Design. Patients received 50mg of dry extract of Paullinia cupana orally twice a day for 6 weeks. We assessed both frequency and severity of hot flashes. Results: A total of 18 patients started the Paullinia cupana treatment, and 15 completed the study. Three patients left the study immediately after starting the treatment because of personal difficulties in participation or noncompliance. Of the 15 patients who completed the study 10 had a decrease of more than 50% in hot flash severity scores. During the 6 weeks of treatment, statistically significant decreases were seen in both numbers of hot flashes (p=0.0009) and severity scores (p<0.0001). Paullinia cupana was well tolerated, and there were no instances of discontinuation because of toxicity. Conclusions: Paullinia cupana appears promising for controlling hot flashes. More extensive studies seem warranted. PMID:24488380

  4. Paullinia cupana for control of hot flashes in breast cancer patients: a pilot study.

    PubMed

    Oliveira, Saulo Silva; Del Giglio, Adriana Braz; Lerner, Tatiana Goberstein; Zanellato, Rebecca Melo; Tiemi, Livia; Reifur, Lucas; Santi, Patrícia Xavier; Del Giglio, Auro

    2013-12-01

    To evaluated whether Paullinia cupana decrease number and severity of hot flashes in breast cancer survivors. This was a prospective phase II pilot study. We studied female breast cancer survivors who had completed the cancer treatment 3 months previously and who were experiencing at least 14 hot flashes per week. At least 9 of the 15 patients were required to have a decrease of at least 50% in hot flash severity score in keeping with the Simon Design. Patients received 50mg of dry extract of Paullinia cupana orally twice a day for 6 weeks. We assessed both frequency and severity of hot flashes. A total of 18 patients started the Paullinia cupana treatment, and 15 completed the study. Three patients left the study immediately after starting the treatment because of personal difficulties in participation or noncompliance. Of the 15 patients who completed the study 10 had a decrease of more than 50% in hot flash severity scores. During the 6 weeks of treatment, statistically significant decreases were seen in both numbers of hot flashes (p=0.0009) and severity scores (p<0.0001). Paullinia cupana was well tolerated, and there were no instances of discontinuation because of toxicity. Paullinia cupana appears promising for controlling hot flashes. More extensive studies seem warranted.

  5. Study of Beijiang catchment flash-flood forecasting model

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Li, J.; Huang, S.; Dong, Y.

    2015-05-01

    Beijiang catchment is a small catchment in southern China locating in the centre of the storm areas of the Pearl River Basin. Flash flooding in Beijiang catchment is a frequently observed disaster that caused direct damages to human beings and their properties. Flood forecasting is the most effective method for mitigating flash floods, the goal of this paper is to develop the flash flood forecasting model for Beijiang catchment. The catchment property data, including DEM, land cover types and soil types, which will be used for model construction and parameter determination, are downloaded from the website freely. Based on the Liuxihe Model, a physically based distributed hydrological model, a model for flash flood forecasting of Beijiang catchment is set up. The model derives the model parameters from the terrain properties, and further optimized with the observed flooding process, which improves the model performance. The model is validated with a few observed floods occurred in recent years, and the results show that the model is reliable and is promising for flash flood forecasting.

  6. Flash droughts in a typical humid and subtropical basin: A case study in the Gan River Basin, China

    NASA Astrophysics Data System (ADS)

    Zhang, Yuqing; You, Qinglong; Chen, Changchun; Li, Xin

    2017-08-01

    As opposed to traditional drought events, flash droughts evolve rapidly and are characterized by soil moisture deficits. The general lack of high resolution soil moisture and evapotranspiration data makes identifying flash droughts at short-term scales (pentads or weeks) nearly impossible, particularly at the basin scale. In this study, we investigated the spatial patterns, temporal characteristics, and related mechanisms of flash droughts in a humid and subtropical basin (Gan River Basin) in China. The variable infiltration capacity (VIC) model can accurately reflect hydrological processes in the Gan River Basin at daily and monthly time scales; here, flash droughts were determined based on VIC outputs (soil moisture and evapotranspiration) and meteorological observations (maximum temperature and precipitation) during the growing season (March-October) from 1961 to 2013. We classified flash droughts into two categories (heat wave and precipitation deficit flash droughts) based on the formation mechanisms. Heat wave flash droughts are high temperature driven events, high temperatures (heat waves) cause evapotranspiration to increase and soil moisture to decrease rapidly. The main driver of precipitation deficit flash droughts is precipitation deficits, which cause soil moisture to drop and in turn cause evapotranspiration anomalies to decrease and temperature to increase. The northern part of the basin is apparently vulnerable to heat wave flash droughts, whereas precipitation deficit flash droughts tend to occur across the central and southern parts of the basin. Precipitation deficit flash droughts are more common than heat wave flash droughts in general. Both types of flash droughts became significantly more frequent from 1997 to 2013. These increases in both types of flash droughts are likely attributable to climate-related variables such as temperature, precipitation, evapotranspiration, and soil moisture during 1997-2013. As evidenced by our investigation of

  7. Study of liquid jet impingement on screens

    NASA Technical Reports Server (NTRS)

    Dodge, F. T.; Ricker, R. E.

    1976-01-01

    A model is presented for an unconfined flow, such as a free jet, impinging on a screen which incorporates the influence of liquid deflection by the screen. The boundary layer blockage coefficient is introduced. This coefficient depends on the screen weave geometry and the jet impingement angle, and essentially accounts for the increase in fluid particle trajectory length through the screen resulting from the flow deflection. Comparisons were made with previous experimental studies to determine empirical values of the blockage coefficient. It is concluded that the new model reliably predicts the bulk flow and penetration characteristics of an impinging liquid jet interacting with a screen.

  8. Photochemical properties of gemifloxacin: a laser flash photolysis study.

    PubMed

    Xu, Yulie; Liu, Yancheng; Zhao, Jianfeng; Li, Haixia; Zhang, Peng; Wang, Wenfeng

    2015-02-01

    The photochemical properties of gemifloxacin (GEFX), a fluoroquinolone antibacterial drug that exhibits phototoxicity toward biological substrates, were studied in aqueous solutions by laser flash photolysis (LFP) and pulse radiolysis. GEFX triplet state ((3)GEFX(∗)) absorption spectra showed maximum absorption at 510nm. (3)GEFX(∗) was quenched by naproxen (NAP) via energy transfer with a rate constant of 1.2×10(8)dm(3)mol(-1)s(-1). The energy of (3)GEFX(∗) was 266kJmol(-1) and the transient absorption spectra showed direct evidence of electron transfer from 2'-deoxyguanosine-5'-monophosphate, N,N,N',N'-tetramethyl-p-phenylenediamine, and tryptophan to (3)GEFX(∗) with bimolecular reaction rate constants of 4.1×10(6), 2.0×10(7), and 2.2×10(7)dm(3)mol(-1)s(-1), respectively. The rate constants for reactions of GEFX with OH, eaq(-) were found to be 1.5×10(10) and 1.4×10(10)dm(3)mol(-1)s(-1), respectively. The mechanisms and products of the photosensitive damage of lysozyme were related to the GEFX concentration, irradiation time, and ambient conditions. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Flash photolysis and pulse radiolysis studies on elastin hydrolysates.

    PubMed

    Sionkowska, Alina

    2013-08-05

    The formation of reactive species and free radicals in water soluble elastin hydrolysates have been investigated by pulse radiolysis and flash photolysis. Elastin hydrolysates were obtained by hydrolysis of elastin extracted from aorta. An investigation of the photochemical properties of elastin hydrolysates in water was carried out using nanosecond laser irradiation. The transient spectra of elastin hydrolysates solution excited at 266 nm showed two bands. One of them with maximum at 295 nm and the second one with maximum at 400 nm. The reactions of hydrated electrons and ˙OH radicals with elastin have been studied by pulse radiolysis. In the absorption spectra of products resulting from the reaction of elastin with e(aq)(-) small maximum absorption in UV and visible light was observed. In the absorption spectra of products resulting from the reaction of the hydroxyl radicals with elastin two bands were observed. The first one at 320 nm and the second one at 410 nm. Reaction of OH radicals with elastin hydrolysates lead to formation of Tyr phenoxyl radicals with absorption at 410 nm. The influence of the addition of sodium azide NaN3 on the formation of the transients was evaluated. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. [Laser flash photolysis, EPR and Raman studies of liquids at elevated pressures

    SciTech Connect

    Eyring, E.M.

    1992-01-01

    The proposed research will solve a number of analytical chemical problems in solutions with measurement techniques that benefit from the use of elevated hydrostatic pressures: stopped-flow spectrophotometry (Gd[sup 3+] + L(ligand), [RuL[sub 5]H[sub 2]O][sup 2+], laser flash photolysis of Mo(CO)[sub 6] + L, flash photolysis of binuclear metalloproteins), EPR spectroscopy (Gd[sup 3+] ion-exchanged into ETS-10 and ETAS-10 molecular sieves), laser flash photolysis kinetic studies of Mo(CO)[sub 6]-2,2'-bipyridine, and electrochemical studies of metalloporphyrins using resonance Raman spectroscopy.

  11. [Laser flash photolysis, EPR and Raman studies of liquids at elevated pressures

    SciTech Connect

    Eyring, E.M.

    1992-10-01

    The proposed research will solve a number of analytical chemical problems in solutions with measurement techniques that benefit from the use of elevated hydrostatic pressures: stopped-flow spectrophotometry (Gd{sup 3+} + L(ligand), [RuL{sub 5}H{sub 2}O]{sup 2+}, laser flash photolysis of Mo(CO){sub 6} + L, flash photolysis of binuclear metalloproteins), EPR spectroscopy (Gd{sup 3+} ion-exchanged into ETS-10 and ETAS-10 molecular sieves), laser flash photolysis kinetic studies of Mo(CO){sub 6}-2,2`-bipyridine, and electrochemical studies of metalloporphyrins using resonance Raman spectroscopy.

  12. Fuels characterization studies. [jet fuels

    NASA Technical Reports Server (NTRS)

    Seng, G. T.; Antoine, A. C.; Flores, F. J.

    1980-01-01

    Current analytical techniques used in the characterization of broadened properties fuels are briefly described. Included are liquid chromatography, gas chromatography, and nuclear magnetic resonance spectroscopy. High performance liquid chromatographic ground-type methods development is being approached from several directions, including aromatic fraction standards development and the elimination of standards through removal or partial removal of the alkene and aromatic fractions or through the use of whole fuel refractive index values. More sensitive methods for alkene determinations using an ultraviolet-visible detector are also being pursued. Some of the more successful gas chromatographic physical property determinations for petroleum derived fuels are the distillation curve (simulated distillation), heat of combustion, hydrogen content, API gravity, viscosity, flash point, and (to a lesser extent) freezing point.

  13. Two-frame flash x-radiography system for target implosion studies

    SciTech Connect

    Chang, J.; Fehl, D.L.

    1980-01-01

    A two-frame flash x-radiography system has been developed to study target implosion dynamics. It is capable of taking two time separated 3 ns exposure x-ray shadowgrams of a particle beam driven target implosion.

  14. Numerical studies of solar chromospheric jets

    NASA Astrophysics Data System (ADS)

    Iijima, Haruhisa

    2016-03-01

    short chromospheric jets. The taller jets tend to follow ballistic trajectory. The contribution of the coronal conditions are quantitatively modeled in the form of a power law based on the amplification of shock waves under the density stratified medium. In Chapter 5, the role of the magnetic field is investigated using the two-dimensional simulations. We distinguish the contribution of the corona and magnetic field using the power law. The average magnetic field strength produces only a small effect on the scale of chromospheric jets. The observed regional difference is mainly explained by the difference of the coronal conditions, which is caused by the different magnetic field structure. We also find shorter chromospheric jets above the strong magnetic flux tube. This is in contrast to the observational studies. In Chapter 6, a three-dimensional simulation is presented to investigate the effect of three-dimensionality on the scale of chromospheric jets and the dependence on the photospheric magnetic field structure. The tall chromospheric jets with the maximum height of 10-11 Mm and lifetime of 8-10 min are formed. These tall jets are located above the strong magnetic field concentration. This result is different from the two-dimensional study and consistent with the observational reports. The strongly entangled chromospheric magnetic field drives these tall chromospheric jets through the Lorentz force. We also find that the produced chromospheric jets form a cluster with the diameter of several Mm with finer strands. In Chapter 7, we summarize and discuss our new findings and their implications for the solar chromospheric jets. The regional difference of chromospheric jets is explained through the coronal temperature and density, which is produced by the heating process with the different strength and structure of the magnetic field. The observational relation between the magnetic network and chromospheric jets are interpreted through the magii netic energy release

  15. Flash spectroscopic studies of the kinetics of the halorhodopsin photocycle

    NASA Technical Reports Server (NTRS)

    Lanyi, J. K.; Vodyanoy, V.

    1986-01-01

    The photoreactions of halorhodopsin are complicated by the fact that the parent pigment and its photoproducts interact with chloride. Thus, in any photoreaction scheme at least four species have to be accounted for: HR565 and HR578 Cl-, as well as HR640 and HR520 Cl-. A photocycle scheme proposed earlier places the two main photointermediates of halorhodopsin, HR520 Cl- and HR640, into a single photocycle, with a chloride-dependent equilibrium between them [Oesterhelt, D., Hegemann, P., & Tittor, J. (1985) EMBO J. 4, 2351-2356]. This scheme, with the additional feature of direct photoproduction of HR640 from HR565, was tested in this work by using numerical solutions of the appropriate differential equations to simulate flash-induced absorption changes at 500 nm (production of HR520 Cl-) and at 660 nm (production of HR640). The time scale of the simulation was ms following the flash. Comparison of the simulated curves with experimental traces yielded a unique set of three rate constants. The proposed photocycle scheme and these rate constants predict well the shapes and amplitudes of flash traces at various chloride concentrations. It appears from the photocycle scheme, and the numerical values of rate constants, that chloride is bound with high affinity to the parent halorhodopsin molecule, but with much lower affinity to its main photointermediate. This may be the consequence of the fact that in the parent halorhodopsin in the retinal configuration is all-trans, but in the two photointermediates it is 13-cis.

  16. Flash spectroscopic studies of the kinetics of the halorhodopsin photocycle

    NASA Technical Reports Server (NTRS)

    Lanyi, J. K.; Vodyanoy, V.

    1986-01-01

    The photoreactions of halorhodopsin are complicated by the fact that the parent pigment and its photoproducts interact with chloride. Thus, in any photoreaction scheme at least four species have to be accounted for: HR565 and HR578 Cl-, as well as HR640 and HR520 Cl-. A photocycle scheme proposed earlier places the two main photointermediates of halorhodopsin, HR520 Cl- and HR640, into a single photocycle, with a chloride-dependent equilibrium between them [Oesterhelt, D., Hegemann, P., & Tittor, J. (1985) EMBO J. 4, 2351-2356]. This scheme, with the additional feature of direct photoproduction of HR640 from HR565, was tested in this work by using numerical solutions of the appropriate differential equations to simulate flash-induced absorption changes at 500 nm (production of HR520 Cl-) and at 660 nm (production of HR640). The time scale of the simulation was ms following the flash. Comparison of the simulated curves with experimental traces yielded a unique set of three rate constants. The proposed photocycle scheme and these rate constants predict well the shapes and amplitudes of flash traces at various chloride concentrations. It appears from the photocycle scheme, and the numerical values of rate constants, that chloride is bound with high affinity to the parent halorhodopsin molecule, but with much lower affinity to its main photointermediate. This may be the consequence of the fact that in the parent halorhodopsin in the retinal configuration is all-trans, but in the two photointermediates it is 13-cis.

  17. A dynamic fMRI study of illusory double-flash effect on human visual cortex.

    PubMed

    Zhang, Nanyin; Chen, Wei

    2006-06-01

    Functional MRI (fMRI) combined with the paired-stimuli paradigms (referred as dynamic fMRI) was used to study the "illusory double-flash" effect on brain activity in the human visual cortex. Three experiments were designed. The first two experiments aimed to examine the cross-modal neural interaction between the visual and auditory sensory systems caused by the illusory double-flash effect using combined auditory (beep sound) and visual (light flash) stimuli. The fMRI signal in the visual cortex was significantly increased in response to the illusory double flashes compared to the physical single flash when the inter-stimuli delay between the auditory and visual stimuli was 25 ms. This increase disappeared when the delay was prolonged to approximately 300 ms. These results reveal that the illusory double-flash effect can significantly affect the brain activity in the visual cortex, and the degree of this effect is dynamically sensitive to the inter-stimuli delay. The third experiment was to address the spatial differentiation of brain activation in the visual cortex in response to the illusory double-flash stimulation. It was found that the illusory double-flash effect in the human visual cortex is much stronger in the periphery than the fovea. This finding suggests that the periphery may be involved in high-level brain processing beyond the retinotopic visual perception. The behavioral measures conducted in this study indicate an excellent correlation between the fMRI results and behavioral performance. Finally, this work demonstrates a unique merit of fMRI for providing both temporal and spatial information regarding cross-modal neural interaction between different sensory systems.

  18. Experimental and Theoretical Studies of Axisymmetric Free Jets

    NASA Technical Reports Server (NTRS)

    Love, Eugene S.; Grigsby, Carl E.; Lee, Louise P.; Woodling, Mildred J.

    1959-01-01

    Some experimental and theoretical studies have been made of axisymmetric free jets exhausting from sonic and supersonic nozzles into still air and into supersonic streams with a view toward problems associated with propulsive jets and the investigation of these problems. For jets exhausting into still air, consideration is given to the effects of jet Mach number, nozzle divergence angle, and jet static pressure ratio upon jet structure, jet wavelength, and the shape and curvature of the jet boundary. Studies of the effects of the ratio of specific heats of the jets are included are observations pertaining to jet noise and jet simulation. For jets exhausting into supersonic streams, an attempt has been made to present primarily theoretical certain jet interference effects and in formulating experimental studies. The primary variables considered are jet Mach number, free stream Mach number, jet static pressure ratio, ratio of specific heats of the jet, nozzle exit angle, and boattail angle. The simulation problem and the case of a hypothetical hypersonic vehicle are examined, A few experimental observations are included.

  19. Evaluation of the Flash effect in breast irradiation using TomoDirect: an investigational study

    PubMed Central

    Kang, Dae Gyu; Park, Sung Ill; Kim, Sung Hwan; Chung, Mi Joo; Lee, Kwang-Man; Lee, Jong Hoon

    2015-01-01

    Flash is a specified function in TomoDirect that enables beam expansion by opening additional leaves to the target. This study assessed the theoretical dose distribution resulting from Flash in breast irradiation using TomoDirect. A cylindrical phantom that enabled dose distribution of the breast was used for verifying the effect of planning target volume (PTV) contouring and Flash. A total of 18 Gy in 10 fractions were prescribed to the PTV. Five PTVs were then created by Contracting this contour by 0, 1, 2, 3, 4 and 5 mm, giving PTV-x. Flash ±x is defined by opening x (number) of the leaves. The Flash effect in the air was compared with each set-up error of 5, 10 and 15 mm, respectively. The minimum PTV dose from PTV-1 to PTV-3 increased from 13.88 Gy to 15.86 Gy. In contrast, Dmin in PTV-4 and PTV-5 was 17.80 Gy in 98.88% of the prescription dose. Without Flash, when 5-, 10- and 15-mm set-up errors applied in the PTV, relative doses of 87.88, 23.73 and 7.94% were observed, respectively. However, in Flash 3, which was equal to the usual air margin of 1.875 cm, a relative dose of 104.24% ± 0.30% was observed, irrespective of set-up errors (5 mm to 15 mm). Flash opening is useful for countervailing set-up errors in breast cancer patients who receive breast irradiation with TomoDirect. PMID:25672612

  20. Evaluation of the Flash effect in breast irradiation using TomoDirect: an investigational study.

    PubMed

    Kang, Dae Gyu; Park, Sung Ill; Kim, Sung Hwan; Chung, Mi Joo; Lee, Kwang-Man; Lee, Jong Hoon

    2015-03-01

    Flash is a specified function in TomoDirect that enables beam expansion by opening additional leaves to the target. This study assessed the theoretical dose distribution resulting from Flash in breast irradiation using TomoDirect. A cylindrical phantom that enabled dose distribution of the breast was used for verifying the effect of planning target volume (PTV) contouring and Flash. A total of 18 Gy in 10 fractions were prescribed to the PTV. Five PTVs were then created by Contracting this contour by 0, 1, 2, 3, 4 and 5 mm, giving PTV-x. Flash ±x is defined by opening x (number) of the leaves. The Flash effect in the air was compared with each set-up error of 5, 10 and 15 mm, respectively. The minimum PTV dose from PTV-1 to PTV-3 increased from 13.88 Gy to 15.86 Gy. In contrast, Dmin in PTV-4 and PTV-5 was 17.80 Gy in 98.88% of the prescription dose. Without Flash, when 5-, 10- and 15-mm set-up errors applied in the PTV, relative doses of 87.88, 23.73 and 7.94% were observed, respectively. However, in Flash 3, which was equal to the usual air margin of 1.875 cm, a relative dose of 104.24% ± 0.30% was observed, irrespective of set-up errors (5 mm to 15 mm). Flash opening is useful for countervailing set-up errors in breast cancer patients who receive breast irradiation with TomoDirect. © The Author 2015. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  1. Laser flash photolysis study of photoionization in fluoroquinolones.

    PubMed

    Monti, Sandra; Sortino, Salvatore

    2002-11-01

    A laser flash photolysis investigation was carried out on the mechanism of electron photoejection in fluoroquinolone derivatives, bearing either electron donating or electron accepting substituents in position 8, laser excited at lambda(exc) = 355 nm in neutral aqueous solutions. The dependence of the hydrated electron absorption at 720 nm on the laser intensity and on the presence of N2O as electron scavenger evidenced that in enoxacin, norfloxacin, and lomefloxacin the photoionization is predominantly two-photon. With rufloxacin, besides the two-photon process, a one photon contribution with a quantum yield of 0.034 was measured.

  2. Study Of Boosted W-Jets And Higgs-Jets With the SiFCC Detector

    SciTech Connect

    Yu, Shin-Shan; Chekanov, Sergei; Gray, Lindsey; Kotwal, Ashutosh; Sen, Sourav; Tran, Nhan Viet

    2016-11-04

    We study the detector performance in the reconstruction of hadronically-decaying W bosons and Higgs bosons at very high energy proton colliders using a full GEANT4 simulation of the SiFCC detector. The W and Higgs bosons carry transverse momentum in the multi-TeV range, which results in collimated decay products that are reconstructed as a single jet. We present a measurement of the energy response and resolution of boosted W-jets and Higgs-jets and show the separation of two sub-jets within the boosted boson jet.

  3. Experimental Studies of Coaxial Jet Flows

    NASA Astrophysics Data System (ADS)

    Behrouzi, Parviz; McGuirk, James J.

    An experimental study was carried out to investigate the effect of coaxial nozzle operating conditions on near-field jet plume development. The study was conducted in a low speed water tunnel as well as in a high-speed airflow nozzle test facility. Laser Doppler Anemometry (LDA) and Laser Induced Fluorescence (LIF) techniques were employed to identify the flow structure as well as the mean velocity and turbulence structure of a coaxial nozzle under low speed flow conditions. Schlieren flow visualization, LDA and nozzle wall static pressure measurement surveys were performed in high speed flows. The effect of a nozzle shroud on jet development was studied and found very effective on suppression of the shock cells and on reduction of turbulence levels within the core region. The effect of the outer and inner Nozzle Pressure Ratios on shock cell structure and the nozzle internal wall pressure field were documented. LDA measurements in the water tunnel confirmed that the flow pattern produced of the Reynolds numbers and velocity ratios selected for this study was typical of practically occurring developing jet flow fields. Sufficient measured profiles of velocities, turbulence quantities and nozzle wall static pressures as well as jet plume images have been captured to serve as benchmark validation data for time-averaged turbulence-model-based RANS CFD predictions.

  4. Computational Study of Air Entrainment by Plunging Jets-Influence of Jet Inclination

    NASA Astrophysics Data System (ADS)

    Deshpande, Suraj; Trujillo, Mario

    2012-11-01

    The process of air entrainment by a continuous liquid jet plunging into a quiescent liquid pool is studied computationally. Our earlier study [APS2011] focused on shallow impacts and the discernible periodicity of air cavity formation. Here, we consider the effect of jet angle. For steep impacts, we see a chaotic formation of small cavities, in agreement with the literature. To explain the difference, we track evolution of the flow from initial impact to quasi-stationary state, for different jet inclinations. The initial impact always yields a large air cavity, regardless of jet angle. Difference emerges in the quasi-stationary state where shallow jets demonstrate the periodicity but the steep jets do not. We show that this is a manifestation of the air entrainment being a function of flow disturbance. For shallow jets, the disturbance originates from strong wavelike motion of the cavity which results in a total disruption of the jet. Thus, the resulting cavities are large and occur periodically. For the steep jets, entrainment happens by collapse of a thin gas film uniformly enshrouding the submerged jet. Such a thin film is very sensitive to the local flow disturbances. Thus, its collapse occurs stochastically all around the jet causing chaotic entrainment of small air pocket.

  5. Escitalopram reduces hot flashes in nondepressed menopausal women: A pilot study.

    PubMed

    Defronzo Dobkin, Roseanne; Menza, Matthew; Allen, Lesley A; Marin, Humberto; Bienfait, Karina L; Tiu, Jade; Howarth, Jennifer

    2009-01-01

    Hot flashes are one of the most troubling manifestations of menopause, affecting about 80% of women. Due to recent controversies about hormone replacement therapy, many women seek alternative treatments. The use of antidepressants to treat hot flashes and other menopausal symptoms has been an active area of investigation. However, the majority of past research in this area has included women with significant medical or psychiatric histories that may influence treatment response. This was the first study to examine the impact of escitalopram on hot flashes, mood, sleep, and quality of life in a sample of healthy nondepressed menopausal women. This study enrolled 25 menopausal women who had no significant psychiatric or medical history. All women were treated with escitalopram (10 to 20 mg flexibly dosed) for 8 weeks. The active treatment phase was preceded by a single-blind placebo lead-in period. Over the course of the study, women reported significant decreases in both hot flash frequency and severity as well as improvements in dysphoria, anxiety, quality of life, and sleep. These preliminary findings suggest that escitalopram may be a feasible and effective option for treating hot flashes and other menopausal symptoms in healthy women who might not ordinarily consider antidepressant treatment.

  6. Escitalopram Reduces Hot Flashes in Non-depressed Menopausal Women: A Pilot Study

    PubMed Central

    Dobkin, Roseanne DeFronzo; Menza, Matthew; Allen, Lesley A.; Marin, Humberto; Bienfait, Karina L.; Tiu, Jade; Howarth, Jennifer

    2009-01-01

    Background Hot flashes are one of the most troubling manifestations of menopause, affecting about 80% of women. Due to recent controversies about hormone replacement therapy (HRT), many women are seeking alternative treatments. The use of antidepressants to treat hot flashes and other menopausal symptoms has been an active area of investigation. However, the majority of past research in this area has included women with significant medical or psychiatric histories that may influence treatment response. This was the first study to examine the impact of escitalopram on hot flashes, mood, sleep, and quality of life in a healthy sample of non-depressed menopausal women. Methods Twenty-five menopausal women, with no significant psychiatric or medical history, were enrolled. All women were treated with escitalopram (10-20mg flexibly dosed) for 8 weeks. The active treatment phase was preceded by a single blind placebo lead-in period. Results Over the course of the study, women reported significant decreases in both hot flash frequency and severity and improvements in dysphoria, anxiety, quality of life, and sleep. Conclusions These preliminary findings suggest that escitalopram may be a feasible and effective option for treating hot flashes and other menopausal symptoms in healthy women who might not ordinarily consider antidepressant treatment. PMID:19439155

  7. Theoretical and experimental study of the formation conditions of stepped leaders in negative flashes

    SciTech Connect

    Xie, Shijun; Zeng, Rong; Zhuang, Chijie; Li, Jianming

    2015-08-15

    Natural lightning flashes are stochastic and uncontrollable, and thus, it is difficult to observe the formation process of a downward negative stepped leader (NSL) directly and in detail. This situation has led to some dispute over the actual NSL formation mechanism, and thus has hindered improvements in the lightning shielding analysis model. In this paper, on the basis of controllable long air gap discharge experiments, the formation conditions required for NSLs in negative flashes have been studied. First, a series of simulation experiments on varying scales were designed and carried out. The NSL formation processes were observed, and several of the characteristic process parameters, including the scale, the propagation velocity, and the dark period, were obtained. By comparing the acquired formation processes and the characteristic parameters with those in natural lightning flashes, the similarity between the NSLs in the simulation experiments and those in natural flashes was proved. Then, based on the local thermodynamic equation and the space charge estimation method, the required NSL formation conditions were deduced, and the space background electric field (E{sub b}) was proposed as the primary parameter for NSL formation. Finally, the critical value of E{sub b} required for the formation of NSLs in natural flashes was determined to be approximately 75 kV/m by extrapolation of the results of the simulation experiments.

  8. Experimental study of flapping jets in a soap film

    NASA Astrophysics Data System (ADS)

    Lee, Julia; Kim, Ildoo; Mandre, Shreyas

    2015-11-01

    Plateau and Rayleigh's observation and explanation on jet instability have inspired us over the years and there has been a significant advance in understanding the jet dynamics. Here, we present a quasi-two-dimensional experimental study of flapping jets in a soap film. Newtonian and non-Newtonian solutions are injected in a flowing soap film. Thinning, break-ups, and beads-on-a-string of the jets, and axisymmetric vortices shredded from the flapping jets are visualized. We employ PIV of the flow motion around the jets to gain an understanding of the roles of instabilities in the flow.

  9. LOW-x Dynamics Through Jet Studies

    NASA Astrophysics Data System (ADS)

    Ferencei, Jozef; H1; ZEUS Collaborations

    One of the most challenging aspects of low x proton structure is the study of QCD dynamics - the evolution of partons between different kinematic regimes. In electron-proton deep-inelastic scattering, this can be investigated by studying processes in the target region of the proton - forward going jets. In this paper various measurements made at HERA by the H1 and ZEUS experiments are presented and compared to Monte Carlo models and fixed-order QCD calculations.

  10. Hypnosis for hot flashes among postmenopausal women study: A study protocol of an ongoing randomized clinical trial

    PubMed Central

    2011-01-01

    Background Hot flashes are a highly prevalent problem associated with menopause and breast cancer treatments. The recent findings from the Women's Health Initiative have important implications for the significance of a non-hormonal, mind-body intervention for hot flashes in breast cancer survivors. Women who take hormone therapy long-term may have a 1.2 to 2.0 fold increased risk of developing breast cancer. In addition, it is now known that hormone therapy with estrogen and progestin is associated with increased risk of cardiovascular disease and stroke. Currently there are limited options to hormone replacement therapy as non-hormonal pharmacological agents are associated with only modest activity and many adverse side effects. Because of this there is a need for more alternative, non-hormonal therapies. Hypnosis is a mind-body intervention that has been shown to reduce self-reported hot flashes by up to 68% among breast cancer survivors, however, the use of hypnosis for hot flashes among post-menopausal women has not been adequately explored and the efficacy of hypnosis in reducing physiologically measured hot flashes has not yet been determined. Methods/design A sample of 180 post-menopausal women will be randomly assigned to either a 5-session Hypnosis Intervention or 5-session structured-attention control with 12 week follow-up. The present study will compare hypnosis to a structured-attention control in reducing hot flashes (perceived and physiologically monitored) in post-menopausal women in a randomized clinical trial. Outcomes will be hot flashes (self-report daily diaries; physiological monitoring; Hot Flash Related Daily Interference Scale), anxiety (State-Trait Anxiety Inventory; Hospital Anxiety and Depression Scale (HADS); anxiety visual analog scale (VAS rating); depression (Center for Epidemiologic Studies Depression Scale), sexual functioning (Sexual Activity Questionnaire), sleep quality (Pittsburgh Sleep Quality Index) and cortisol. Discussion

  11. Hypnosis for hot flashes among postmenopausal women study: a study protocol of an ongoing randomized clinical trial.

    PubMed

    Elkins, Gary R; Fisher, William I; Johnson, Aimee K

    2011-10-11

    Hot flashes are a highly prevalent problem associated with menopause and breast cancer treatments. The recent findings from the Women's Health Initiative have important implications for the significance of a non-hormonal, mind-body intervention for hot flashes in breast cancer survivors. Women who take hormone therapy long-term may have a 1.2 to 2.0 fold increased risk of developing breast cancer. In addition, it is now known that hormone therapy with estrogen and progestin is associated with increased risk of cardiovascular disease and stroke. Currently there are limited options to hormone replacement therapy as non-hormonal pharmacological agents are associated with only modest activity and many adverse side effects. Because of this there is a need for more alternative, non-hormonal therapies. Hypnosis is a mind-body intervention that has been shown to reduce self-reported hot flashes by up to 68% among breast cancer survivors, however, the use of hypnosis for hot flashes among post-menopausal women has not been adequately explored and the efficacy of hypnosis in reducing physiologically measured hot flashes has not yet been determined. A sample of 180 post-menopausal women will be randomly assigned to either a 5-session Hypnosis Intervention or 5-session structured-attention control with 12 week follow-up. The present study will compare hypnosis to a structured-attention control in reducing hot flashes (perceived and physiologically monitored) in post-menopausal women in a randomized clinical trial. Outcomes will be hot flashes (self-report daily diaries; physiological monitoring; Hot Flash Related Daily Interference Scale), anxiety (State-Trait Anxiety Inventory; Hospital Anxiety and Depression Scale (HADS); anxiety visual analog scale (VAS rating); depression (Center for Epidemiologic Studies Depression Scale), sexual functioning (Sexual Activity Questionnaire), sleep quality (Pittsburgh Sleep Quality Index) and cortisol. This study will be the first full

  12. Studies of ultracompact jets with space VLBI

    NASA Astrophysics Data System (ADS)

    Lobanov, Andrei

    Imaging and polarimetry of radio emission on microarcsecond scales provided by VSOP-2 and RadioAstron will offer a range of possibilities for studying ultracompact regions of relativistic jets and extreme vicinity of the central supermassive bodies in AGN. Both missions will address a number of outstanding problems in AGN physics, including the site and the mechanism of jet formation, acceleration of relativistic flows, structure of magnetic field in the vicinity of the central engine of AGN, and the fundamental question of the physical nature of the central massive objects in galaxies. Combining space VLBI observations with variability studies made in the X-ray, and gamma-ray bands will enable locating accurately the sites of high-enenrgy continuum production in AGN. Prospects and potentials of these lines of study with space VLBI will be reviewed.

  13. Analytical study of twin-jet shielding

    NASA Technical Reports Server (NTRS)

    Gerhold, C. H.

    1982-01-01

    Progress in the refinement and evaluation of an analytical jet shielding model are summarized. The model consists of a point noise source impinging on a cylinder of heated flow in which the temperature and velocity are uniform across the cross section of the jet. The shielding jet is infinite in extent along the jet axis and the radius of the jet is constant. The analytical model was compared to experimental data for a point noise source impinging on an ambient temperature, subsonic jet and on a subsonic simulated hot jet using helium as the flow medium. Results of these comparisons are discussed.

  14. Risk factors for hot flashes among women undergoing the menopausal transition: baseline results from the Midlife Women's Health Study

    PubMed Central

    Gallicchio, Lisa; Miller, Susan R.; Kiefer, Judith; Greene, Teresa; Zacur, Howard A.; Flaws, Jodi A.

    2015-01-01

    Objective The aim of this study was to examine the associations between demographic characteristics, health behaviors, hormone concentrations, and the experiencing of any, current, more severe, and more frequent midlife hot flashes. Methods Baseline data were analyzed from 732 women aged 45 to 54 years enrolled in the Midlife Women's Health Study. A clinic visit was conducted to collect blood samples for hormone assays and to measure ovarian volume using transvaginal ultrasound. A self-administered questionnaire ascertained information on demographic factors, health habits, and hot flashes history. Multivariable logistic regression was conducted to examine the associations between potential risk factors and the hot flashes outcomes. Results Approximately 45% of participants reported experiencing midlife hot flashes. In the covariate-adjusted models, older age, peri-menopausal status, current and former cigarette smoking, and depressive symptoms were significantly associated with increased odds of all of the hot flashes outcomes. In addition, history of oral contraceptive use was associated with increased odds of any hot flashes. In contrast, higher current alcohol intake was significantly associated with decreased odds of any, current, and more severe hot flashes. Higher estradiol and progesterone concentrations were significantly associated with decreased odds of all hot flashes outcomes. Conclusions Although the temporalities of such associations are not known due to the cross-sectional nature of the data, these observed relationships can help to identify women at risk for hot flashes. PMID:25783472

  15. Risk factors for hot flashes among women undergoing the menopausal transition: baseline results from the Midlife Women's Health Study.

    PubMed

    Gallicchio, Lisa; Miller, Susan R; Kiefer, Judith; Greene, Teresa; Zacur, Howard A; Flaws, Jodi A

    2015-10-01

    The aim of this study was to examine the associations of demographic characteristics, health behaviors, and hormone concentrations with the experience of any, current, more severe, and more frequent midlife hot flashes. Baseline data from 732 women aged 45 to 54 years who were enrolled in the Midlife Women's Health Study were analyzed. A clinic visit was conducted to collect blood samples for hormone assays and to measure ovarian volume using transvaginal ultrasound. A self-administered questionnaire ascertained information on demographic factors, health habits, and hot flash history. Multivariable logistic regression was conducted to examine associations between potential risk factors and hot flash outcomes. Approximately 45% of participants reported experiencing midlife hot flashes. In covariate-adjusted models, older age, perimenopause status, current and past cigarette smoking, and depressive symptoms were significantly associated with increased odds of all of the hot flash outcomes. In addition, history of oral contraceptive use was associated with increased odds of any hot flashes. In contrast, higher current alcohol intake was significantly associated with decreased odds of any, current, and more severe hot flashes. Higher estradiol and progesterone concentrations were significantly associated with decreased odds of all hot flash outcomes. Although the temporality of such associations is not known because of the cross-sectional nature of the data, these observed relationships can help to identify women at risk for hot flashes.

  16. A study on flash sintering and related phenomena in titania and its composite with alumina

    NASA Astrophysics Data System (ADS)

    Shikhar

    In 2010, Cologna et. al. [1] reported that with a help of small electric field 120 Vcm-1, the sintering temperature of 3 mol % yittria stabilized zirconia could be brought down to 850°C from 1450°C. On top of reducing the temperature requirements, the green sample could be sintered from starting density of 50% to near full density in mere 5 seconds, a sintering rate three orders of magnitude higher than conventional methods. This discovery led to the emergence of a new field of enhanced sintering with electric field, named "Flash Sintering". The objective of this thesis is to understand the phenomenological behavior of flash-sintering and related phenomena on titania and its composites with alumina at elevated temperature. The possible mechanisms to explain flash sintering are discussed: Joule heating and the avalanche of defect generation [2], both induced by the rapid rise in conductivity just before the onset of the flash. Apparently, both mechanisms play a role. The thesis covers the response of pure titania and composites of titania-alumina under flash and compared with conventional sintering. We start with the sintering behavior of pure titania and observe lowering of sintering temperature requirements with higher applied electric field. The conductivity of titania during flash is also measured, and compared with the nominal conductivity of titania at equivalent temperatures. The conductivity during flash is determined to be have a different activation energy. For the composites of titania-alumina, effect of flash on the constrained sintering was studied. It is a known fact that sintering of one component of composite slows down when the other component of a different densification rate is added to it, called constrained sintering. In our case, large inclusions of alumina particles were added to nano-grained titania green compact that hindered its densification. Flash sintering was found to be overcoming this problem and near full densification was achieved

  17. Risk of long-term hot flashes after natural menopause: evidence from the Penn Ovarian Aging Study cohort.

    PubMed

    Freeman, Ellen W; Sammel, Mary D; Sanders, Richard J

    2014-09-01

    This study aims to estimate the risk of hot flashes relative to natural menopause and to evaluate the associations of hormone levels, behavioral variables, and demographic variables with the risk of hot flashes after menopause. We performed annual assessment of 255 women who were premenopausal at baseline and reached natural menopause within 16 years of follow-up. The prevalence of moderate/severe hot flashes increased in each premenopausal year, reaching a peak of 46% in the first 2 years after the final menstrual period (FMP). Hot flashes decreased slowly after menopause and did not return to premenopausal levels until 9 years after the FMP. The mean (SD) duration of moderate/severe hot flashes after the FMP was 4.6 (2.9) years (for any hot flashes, 4.9 [3.1] y). One third of women at 10 years or more after menopause continued to experience moderate/severe hot flashes. African-American women (obese and nonobese) and obese white women had significantly greater risks of hot flashes compared with nonobese white women (interaction, P = 0.01). In multivariable analysis, increasing follicle-stimulating hormone levels before the FMP (P < 0.001), decreasing estradiol (odds ratio, 0.87; 95% CI, 0.78-0.96; P = 0.008), and increasing anxiety (odds ratio, 1.05; 95% CI, 1.03-1.06; P < 0.001) were significant risk factors for hot flashes, whereas higher education levels were protective (odds ratio, 0.66; 95% CI, 0.47-0.91; P = 0.011). Moderate/severe hot flashes continue, on average, for nearly 5 years after menopause; more than one third of women observed for 10 years or more after menopause have moderate/severe hot flashes. Continuation of hot flashes for more than 5 years after menopause underscores the importance of determining individual risks/benefits when selecting hormone or nonhormone therapy for menopausal symptoms.

  18. Experimental study of highly viscous impinging jets

    SciTech Connect

    Gomon, M.

    1998-12-01

    The objective of this research is to study the behavior of highly viscous gravity-driven jets filling a container. Matters of interest are the formation of voids in the fluid pool during the filling process and the unstable behavior of the fluid in the landing region which manifests itself as an oscillating motion. The working fluids used in this research are intended to simulate the flow behavior of molten glass. Qualitative and quantitative results are obtained in a parametric study. The fraction of voids present in the fluid pool after the filling of the container is measured for different parameter values of viscosity and mass flow rate. Likewise, frequencies of the oscillating jet are measured. Results are inconclusive with regard to a correlation between parameter settings and void fractions. As for frequencies, power law correlations are established.

  19. Laboratory studies of volcanic jets.

    USGS Publications Warehouse

    Kieffer, S.W.; Sturtevant, B.

    1984-01-01

    Laboratory experiments to study the fluid dynamics of violent volcanic eruptions employed pure gases erupted from small reservoirs. The gases used were Freon 12 and Freon 22, both of high molecular weight and high density, to model heavy, particulate- laden volcanic gases; nitrogen, a moderate molecular weight and density gas with well known thermodynamic properties; and He, a low molecular weight and density gas used as an analogue of steam, the dominant gas of most volcanic eruptions.-W.H.B.

  20. Analytical study of twin-jet shielding

    NASA Technical Reports Server (NTRS)

    Gerhold, C. H.

    1980-01-01

    The development of an analytical model, an aircraft noise prediction computer program, to estimate the shielding of one jet by an adjacent jet in a twin jet configuration, is discussed. Noise estimations included consideration not only of noise sources on the aircraft, but also of the propagation path between source and receiver. A three-dimensional case is considered in which noise source is a discrete frequency point source at rest with respect to the jet axis. The shielding jet is assumed to be a cylinder of heated flow in which the temperature and flow velocity profiles are constant across the jet. The effect on shielding of the orientation of the emitting jet with respect to the shielding jet was investigated. Forward and backward scattering phenomena as well as the influence of jet flow speed were also investigated.

  1. Experimental and theoretical study of combustion jet ignition

    NASA Technical Reports Server (NTRS)

    Chen, D. Y.; Ghoniem, A. F.; Oppenheim, A. K.

    1983-01-01

    A combustion jet ignition system was developed to generate turbulent jets of combustion products containing free radicals and to discharge them as ignition sources into a combustible medium. In order to understand the ignition and the inflammation processes caused by combustion jets, the studies of the fluid mechanical properties of turbulent jets with and without combustion were conducted theoretically and experimentally. Experiments using a specially designed igniter, with a prechamber to build up and control the stagnation pressure upstream of the orifice, were conducted to investigate the formation processes of turbulent jets of combustion products. The penetration speed of combustion jets has been found to be constant initially and then decreases monotonically as turbulent jets of combustion products travel closer to the wall. This initial penetration speed to combustion jets is proportional to the initial stagnation pressure upstream of the orifice for the same stoichiometric mixture. Computer simulations by Chorin's Random Vortex Method implemented with the flame propagation algorithm for the theoretical model of turbulent jets with and without combustion were performed to study the turbulent jet flow field. In the formation processes of the turbulent jets, the large-scale eddy structure of turbulence, the so-called coherent structure, dominates the entrainment and mixing processes. The large-scale eddy structure of turbulent jets in this study is constructed by a series of vortex pairs, which are organized in the form of a staggered array of vortex clouds generating local recirculation flow patterns.

  2. Flash Heating

    NASA Astrophysics Data System (ADS)

    Taylor, G. J.

    2000-03-01

    Meteorites contain millimeter-sized objects called chondrules. They were melted in the solar nebula, the cloud of gas and dust in which the Sun and planets formed. Numerous experiments on rock powders have been done to understand the melting process and the cooling rates chondrules experienced. Most meteorite specialists believe that chondrules formed by flash heating, with almost instantaneous melting, though the length of time they remained molten is uncertain. Can conventional laboratory furnaces heat rock powders rapidly enough to flash melt them? Susan Maharaj and Roger Hewins (Rutgers University, New Brunswick) tested this idea by inserting tiny wires of pure elements (which have precise melting temperatures) into compressed rock powders about 3.5 mm in diameter, and placing the samples into a furnace heated to a range of temperatures. They found that at 1600 C, a sample took only six seconds to reach 1538 C. When placed into a furnace at 1500 C, samples took ten seconds to reach 1495 C. This shows that the flash heating process can be studied in conventional laboratory furnaces.

  3. Chandra enables study of x-ray jets

    PubMed Central

    Schwartz, Daniel

    2010-01-01

    The exquisite angular resolution of the Chandra x-ray telescope has enabled the detection and study of resolved x-ray jets in a wide variety of astronomical systems. Chandra has detected extended jets in our galaxy from protostars, symbiotic binaries, neutron star pulsars, black hole binaries, extragalactic jets in radio sources, and quasars. The x-ray data play an essential role in deducing the emission mechanism of the jets, in revealing the interaction of jets with the intergalactic or intracluster media, and in studying the energy generation budget of black holes. PMID:20378839

  4. Hot Flashes

    MedlinePlus

    ... are due to menopause — the time when menstrual periods become irregular and eventually stop. In fact, hot flashes are the most common symptom of the menopausal transition. How often hot flashes occur varies among women ...

  5. The Study of Internal Deformation Fields in Borosilicate Glass Using X--Ray Flash Photography

    NASA Astrophysics Data System (ADS)

    Grantham, Stephen; Proud, William; Field, John

    2001-06-01

    Studying the ballistic performance of brittle materials such as borosilicate glass is of particular interest in fields such as transparent armour plating, security glazing and blast-proof windows. Here we extend studies already carried out on the response of borosilicate glass to rod impacts^1 by using flash X-rays to look at the damage occurring behind the damage front. Measurements such as this are impossible using conventional high speed cameras due to optical opacity caused by damage. The new technique of 3--dimensional digital flash X-ray speckle photography, which has been successfully applied to polyester^2 and sand^3 specimens is also utilised. The technique involves seeding the specimen with a layer of lead filings and then taking flash X-ray images before and during an impact event. Digital cross-correlation can then be used to make measurements of the internal displacements occurring throughout the specimen. Using a stereoscopic geometry the out-of-plane displacements can also be determined and a full 3--dimensional displacement map constructed. In this paper these two powerful and complementary techniques are used to study the ballistic response of a borosilicate glass sample. ^1Bourne, N.K., Forde, L.C., Millet, J.C.F., Field, J.F., Impact and Penetration of a Borosilicate Glass, J.Phys.IV FRANCE Colloq. C3, 7 (1997), pp 157-162. ^2Synnergren, P., Goldrein, H.T., Dynamic Measurements of Internal Three-Dimensional Displacement Fields with Digital Speckle Photography and Flash X--Rays, Applied Optics 38 (1999) pp 5956-5961. ^3Grantham, S.G., Proud, W.G., Goldrein, H.T., Field, J.F., The Study of Internal Deformation Fields in Granular Materials Using 3--D Digital X--Ray Flash Photography, Laser Interferometry X, Proc. SPIE 4101 (2000) pp 321-328.

  6. Study of Jet Transverse Momentum and Jet Rapidity Dependence on Dijet Azimuthal Decorrelations

    SciTech Connect

    Chakravarthula, Kiran

    2012-01-01

    In a collision experiment involving highly energetic particles such as hadrons, processes at high momentum transfers can provide information useful for many studies involving Quantum Chromodynamics (QCD). One way of analyzing these interactions is through angular distributions. In hadron-hadron collisions, the angular distribution between the two leading jets with the largest transverse momentum (pT ) is affected by the production of additional jets. While soft radiation causes small differences in the azimuthal angular distribution of the two leading jets produced in a collision event, additional hard jets produced in the event have more pronounced influence on the distribution of the two leading jets produced in the collision. Thus, the dijet azimuthal angular distribution can serve as a variable that can be used to study the transition from soft to hard QCD processes in a collision event. This dissertation presents a triple-differential study involving the azimuthal angular distribution and the jet transverse momenta, and jet rapidities of the first two leading jets. The data used for this research are obtained from proton-antiproton (p$\\bar{p}$) collisions occurring at a center of mass energy of 1.96TeV, using the DØ detector in Run II of the Tevatron Collider at the Fermi National Accelerator Laboratory (FNAL) in Illinois, USA. Comparisons are made to perturbative QCD (pQCD) predictions at next-to-leading order (NLO).

  7. Study of laser preheat in magnetic liner inertial fusion using the AMR code FLASH

    NASA Astrophysics Data System (ADS)

    Adams, Marissa; Jennings, Christopher; Slutz, Stephen; Peterson, Kyle; Gourdain, Pierre-Alexandre; University of Rochester; Sandia National Laboratories Collaboration

    2016-10-01

    Magnetic Liner Inertial Fusion (MagLIF) on the Z Pulsed Power Accelerator involves three processes: magnetization, preheat, and compression. An issue with this scheme is the development of instabilities during laser preheat, where the Z-Beamlet laser system may not deposit energy into deuterium fuel uniformly. This study explores potential mixing between liner and fuel, and inner imprinting of seeds on a beryllium liner that may generate late instability growth and shear, using the Eulerian AMR code FLASH. We further investigate potential instability implications of an additional layer of deuterium-tritium ice, as has been proposed and assess the sensitivity of MagLIF implosions to axial variations in fuel preheat; meanwhile testing the expediency of FLASH for these scenarios. FLASH was developed in part by the DOE NNSA ASC and DOE Office of Science ASCR-supported Flash Center at the University of Chicago. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin comapny, for the U.S. Department of Energy's National Nuclear Security Administration under contract No. DE-AC04-94AL85000.

  8. A study of the blown flap/jet flap analogy

    NASA Technical Reports Server (NTRS)

    Hough, G. R.

    1979-01-01

    A study of the blown flap/jet flap analogy has been undertaken. Analytical predictions were made using both improved lifting line and optimized vortex lattice models for the jet flap. Results were compared with experimental data for three propulsive lift systems; the jet augmented flap, the externally blown flap, and the upper surface blown flap. Force increments due to changes in geometry and jet parameters were well approximated in most cases, although the absolute values of the aerodynamic forces were usually underestimated. The relatively simple jet-flap models gave performance predictions of accuracy comparable to more complex analyses.

  9. Hot Flashes

    MedlinePlus

    Diseases and Conditions Hot flashes By Mayo Clinic Staff Hot flashes are sudden feelings of warmth, which are usually most intense over the ... skin may redden, as if you're blushing. Hot flashes can also cause profuse sweating and may ...

  10. Flash Flood Risks and Warning Decisions: A Mental Models Study of Forecasters, Public Officials, and Media Broadcasters in Boulder, Colorado.

    PubMed

    Morss, Rebecca E; Demuth, Julie L; Bostrom, Ann; Lazo, Jeffrey K; Lazrus, Heather

    2015-11-01

    Timely warning communication and decision making are critical for reducing harm from flash flooding. To help understand and improve extreme weather risk communication and management, this study uses a mental models research approach to investigate the flash flood warning system and its risk decision context. Data were collected in the Boulder, Colorado area from mental models interviews with forecasters, public officials, and media broadcasters, who each make important interacting decisions in the warning system, and from a group modeling session with forecasters. Analysis of the data informed development of a decision-focused model of the flash flood warning system that integrates the professionals' perspectives. Comparative analysis of individual and group data with this model characterizes how these professionals conceptualize flash flood risks and associated uncertainty; create and disseminate flash flood warning information; and perceive how warning information is (and should be) used in their own and others' decisions. The analysis indicates that warning system functioning would benefit from professionals developing a clearer, shared understanding of flash flood risks and the warning system, across their areas of expertise and job roles. Given the challenges in risk communication and decision making for complex, rapidly evolving hazards such as flash floods, another priority is development of improved warning content to help members of the public protect themselves when needed. Also important is professional communication with members of the public about allocation of responsibilities for managing flash flood risks, as well as improved system-wide management of uncertainty in decisions. © 2015 Society for Risk Analysis.

  11. Study of J/ψ Production in Jets.

    PubMed

    Aaij, R; Adeva, B; Adinolfi, M; Ajaltouni, Z; Akar, S; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amerio, S; Amhis, Y; An, L; Anderlini, L; Andreassi, G; Andreotti, M; Andrews, J E; Appleby, R B; Archilli, F; d'Argent, P; Arnau Romeu, J; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Baalouch, M; Babuschkin, I; Bachmann, S; Back, J J; Badalov, A; Baesso, C; Baker, S; Balagura, V; Baldini, W; Baranov, A; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Baryshnikov, F; Baszczyk, M; Batozskaya, V; Batsukh, B; Battista, V; Bay, A; Beaucourt, L; Beddow, J; Bedeschi, F; Bediaga, I; Beiter, A; Bel, L J; Bellee, V; Belloli, N; Belous, K; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Beranek, S; Berezhnoy, A; Bernet, R; Bertolin, A; Betancourt, C; Betti, F; Bettler, M-O; van Beuzekom, M; Bezshyiko, Ia; Bifani, S; Billoir, P; Bird, T; Birnkraut, A; Bitadze, A; Bizzeti, A; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Boettcher, T; Bondar, A; Bondar, N; Bonivento, W; Bordyuzhin, I; Borgheresi, A; Borghi, S; Borisyak, M; Borsato, M; Bossu, F; Boubdir, M; Bowcock, T J V; Bowen, E; Bozzi, C; Braun, S; Britsch, M; Britton, T; Brodzicka, J; Buchanan, E; Burr, C; Bursche, A; Buytaert, J; Cadeddu, S; Calabrese, R; Calvi, M; Calvo Gomez, M; Camboni, A; Campana, P; Campora Perez, D H; Capriotti, L; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carniti, P; Carson, L; Carvalho Akiba, K; Casse, G; Cassina, L; Castillo Garcia, L; Cattaneo, M; Cavallero, G; Cenci, R; Chamont, D; Charles, M; Charpentier, Ph; Chatzikonstantinidis, G; Chefdeville, M; Chen, S; Cheung, S-F; Chobanova, V; Chrzaszcz, M; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coco, V; Cogan, J; Cogneras, E; Cogoni, V; Cojocariu, L; Collazuol, G; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombs, G; Coquereau, S; Corti, G; Corvo, M; Costa Sobral, C M; Couturier, B; Cowan, G A; Craik, D C; Crocombe, A; Cruz Torres, M; Cunliffe, S; Currie, R; D'Ambrosio, C; Da Cunha Marinho, F; Dall'Occo, E; Dalseno, J; David, P N Y; Davis, A; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Serio, M; De Simone, P; Dean, C T; Decamp, D; Deckenhoff, M; Del Buono, L; Demmer, M; Dendek, A; Derkach, D; Deschamps, O; Dettori, F; Dey, B; Di Canto, A; Dijkstra, H; Dordei, F; Dorigo, M; Dosil Suárez, A; Dovbnya, A; Dreimanis, K; Dufour, L; Dujany, G; Dungs, K; Durante, P; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Déléage, N; Easo, S; Ebert, M; Egede, U; Egorychev, V; Eidelman, S; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; Ely, S; Esen, S; Evans, H M; Evans, T; Falabella, A; Farley, N; Farry, S; Fay, R; Fazzini, D; Ferguson, D; Fernandez, G; Fernandez Prieto, A; Ferrari, F; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fini, R A; Fiore, M; Fiorini, M; Firlej, M; Fitzpatrick, C; Fiutowski, T; Fleuret, F; Fohl, K; Fontana, M; Fontanelli, F; Forshaw, D C; Forty, R; Franco Lima, V; Frank, M; Frei, C; Fu, J; Funk, W; Furfaro, E; Färber, C; Gallas Torreira, A; Galli, D; Gallorini, S; Gambetta, S; Gandelman, M; Gandini, P; Gao, Y; Garcia Martin, L M; García Pardiñas, J; Garra Tico, J; Garrido, L; Garsed, P J; Gascon, D; Gaspar, C; Gavardi, L; Gazzoni, G; Gerick, D; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gianì, S; Gibson, V; Girard, O G; Giubega, L; Gizdov, K; Gligorov, V V; Golubkov, D; Golutvin, A; Gomes, A; Gorelov, I V; Gotti, C; Govorkova, E; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graverini, E; Graziani, G; Grecu, A; Greim, R; Griffith, P; Grillo, L; Gruberg Cazon, B R; Grünberg, O; Gushchin, E; Guz, Yu; Gys, T; Göbel, C; Hadavizadeh, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hamilton, B; Han, X; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; Hatch, M; He, J; Head, T; Heister, A; Hennessy, K; Henrard, P; Henry, L; van Herwijnen, E; Heß, M; Hicheur, A; Hill, D; Hombach, C; Hopchev, H; Hulsbergen, W; Humair, T; Hushchyn, M; Hutchcroft, D; Idzik, M; Ilten, P; Jacobsson, R; Jaeger, A; Jalocha, J; Jans, E; Jawahery, A; Jiang, F; John, M; Johnson, D; Jones, C R; Joram, C; Jost, B; Jurik, N; Kandybei, S; Karacson, M; Kariuki, J M; Karodia, S; Kecke, M; Kelsey, M; Kenzie, M; Ketel, T; Khairullin, E; Khanji, B; Khurewathanakul, C; Kirn, T; Klaver, S; Klimaszewski, K; Klimkovich, T; Koliiev, S; Kolpin, M; Komarov, I; Koppenburg, P; Kosmyntseva, A; Kozachuk, A; Kozeiha, M; Kravchuk, L; Kreplin, K; Kreps, M; Krokovny, P; Kruse, F; Krzemien, W; Kucewicz, W; Kucharczyk, M; Kudryavtsev, V; Kuonen, A K; Kurek, K; Kvaratskheliya, T; Lacarrere, D; Lafferty, G; Lai, A; Lanfranchi, G; Langenbruch, C; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Leflat, A; Lefrançois, J; Lefèvre, R; Lemaitre, F; Lemos Cid, E; Leroy, O; Lesiak, T; Leverington, B; Li, T; Li, Y; Likhomanenko, T; Lindner, R; Linn, C; Lionetto, F; Liu, X; Loh, D; Longstaff, I; Lopes, J H; Lucchesi, D; Lucio Martinez, M; Luo, H; Lupato, A; Luppi, E; Lupton, O; Lusiani, A; Lyu, X; Machefert, F; Maciuc, F; Maev, O; Maguire, K; Malde, S; Malinin, A; Maltsev, T; Manca, G; Mancinelli, G; Manning, P; Maratas, J; Marchand, J F; Marconi, U; Marin Benito, C; Marinangeli, M; Marino, P; Marks, J; Martellotti, G; Martin, M; Martinelli, M; Martinez Santos, D; Martinez Vidal, F; Martins Tostes, D; Massacrier, L M; Massafferri, A; Matev, R; Mathad, A; Mathe, Z; Matteuzzi, C; Mauri, A; Maurice, E; Maurin, B; Mazurov, A; McCann, M; McNab, A; McNulty, R; Meadows, B; Meier, F; Meissner, M; Melnychuk, D; Merk, M; Merli, A; Michielin, E; Milanes, D A; Minard, M-N; Mitzel, D S; Mogini, A; Molina Rodriguez, J; Monroy, I A; Monteil, S; Morandin, M; Morawski, P; Mordà, A; Morello, M J; Morgunova, O; Moron, J; Morris, A B; Mountain, R; Muheim, F; Mulder, M; Mussini, M; Müller, D; Müller, J; Müller, K; Müller, V; Naik, P; Nakada, T; Nandakumar, R; Nandi, A; Nasteva, I; Needham, M; Neri, N; Neubert, S; Neufeld, N; Neuner, M; Nguyen, T D; Nguyen-Mau, C; Nieswand, S; Niet, R; Nikitin, N; Nikodem, T; Nogay, A; Novoselov, A; O'Hanlon, D P; Oblakowska-Mucha, A; Obraztsov, V; Ogilvy, S; Okhrimenko, O; Oldeman, R; Onderwater, C J G; Otalora Goicochea, J M; Otto, A; Owen, P; Oyanguren, A; Pais, P R; Palano, A; Palutan, M; Papanestis, A; Pappagallo, M; Pappalardo, L L; Parker, W; Parkes, C; Passaleva, G; Pastore, A; Patel, G D; Patel, M; Patrignani, C; Pearce, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perret, P; Pescatore, L; Petridis, K; Petrolini, A; Petrov, A; Petruzzo, M; Picatoste Olloqui, E; Pietrzyk, B; Pikies, M; Pinci, D; Pistone, A; Piucci, A; Placinta, V; Playfer, S; Plo Casasus, M; Poikela, T; Polci, F; Poluektov, A; Polyakov, I; Polycarpo, E; Pomery, G J; Ponce, S; Popov, A; Popov, D; Popovici, B; Poslavskii, S; Potterat, C; Price, E; Price, J D; Prisciandaro, J; Pritchard, A; Prouve, C; Pugatch, V; Puig Navarro, A; Punzi, G; Qian, W; Quagliani, R; Rachwal, B; Rademacker, J H; Rama, M; Ramos Pernas, M; Rangel, M S; Raniuk, I; Ratnikov, F; Raven, G; Redi, F; Reichert, S; Dos Reis, A C; Remon Alepuz, C; Renaudin, V; Ricciardi, S; Richards, S; Rihl, M; Rinnert, K; Rives Molina, V; Robbe, P; Rodrigues, A B; Rodrigues, E; Rodriguez Lopez, J A; Rodriguez Perez, P; Rogozhnikov, A; Roiser, S; Rollings, A; Romanovskiy, V; Romero Vidal, A; Ronayne, J W; Rotondo, M; Rudolph, M S; Ruf, T; Ruiz Valls, P; Saborido Silva, J J; Sadykhov, E; Sagidova, N; Saitta, B; Salustino Guimaraes, V; Sanchez Gonzalo, D; Sanchez Mayordomo, C; Sanmartin Sedes, B; Santacesaria, R; Santamarina Rios, C; Santimaria, M; Santovetti, E; Sarti, A; Satriano, C; Satta, A; Saunders, D M; Savrina, D; Schael, S; Schellenberg, M; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmelzer, T; Schmidt, B; Schneider, O; Schopper, A; Schreiner, H F; Schubert, K; Schubiger, M; Schune, M-H; Schwemmer, R; Sciascia, B; Sciubba, A; Semennikov, A; Sergi, A; Serra, N; Serrano, J; Sestini, L; Seyfert, P; Shapkin, M; Shapoval, I; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, V; Siddi, B G; Silva Coutinho, R; Silva de Oliveira, L; Simi, G; Simone, S; Sirendi, M; Skidmore, N; Skwarnicki, T; Smith, E; Smith, I T; Smith, J; Smith, M; Soares Lavra, L; Sokoloff, M D; Soler, F J P; Souza De Paula, B; Spaan, B; Spradlin, P; Sridharan, S; Stagni, F; Stahl, M; Stahl, S; Stefko, P; Stefkova, S; Steinkamp, O; Stemmle, S; Stenyakin, O; Stevens, H; Stevenson, S; Stoica, S; Stone, S; Storaci, B; Stracka, S; Stramaglia, M E; Straticiuc, M; Straumann, U; Sun, L; Sutcliffe, W; Swientek, K; Syropoulos, V; Szczekowski, M; Szumlak, T; T'Jampens, S; Tayduganov, A; Tekampe, T; Tellarini, G; Teubert, F; Thomas, E; van Tilburg, J; Tilley, M J; Tisserand, V; Tobin, M; Tolk, S; Tomassetti, L; Tonelli, D; Topp-Joergensen, S; Toriello, F; Tournefier, E; Tourneur, S; Trabelsi, K; Traill, M; Tran, M T; Tresch, M; Trisovic, A; Tsaregorodtsev, A; Tsopelas, P; Tully, A; Tuning, N; Ukleja, A; Ustyuzhanin, A; Uwer, U; Vacca, C; Vagnoni, V; Valassi, A; Valat, S; Valenti, G; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; van Veghel, M; Velthuis, J J; Veltri, M; Veneziano, G; Venkateswaran, A; Vernet, M; Vesterinen, M; Viana Barbosa, J V; Viaud, B; Vieira, D; Vieites Diaz, M; Viemann, H; Vilasis-Cardona, X; Vitti, M; Volkov, V; Vollhardt, A; Voneki, B; Vorobyev, A; Vorobyev, V; Voß, C; de Vries, J A; Vázquez Sierra, C; Waldi, R; Wallace, C; Wallace, R; Walsh, J; Wang, J; Ward, D R; Wark, H M; Watson, N K; Websdale, D; Weiden, A; Whitehead, M; Wicht, J; Wilkinson, G; Wilkinson, M; Williams, M; Williams, M P; Williams, M; Williams, T; Wilson, F F; Wimberley, J; Wishahi, J; Wislicki, W; Witek, M; Wormser, G; Wotton, S A; Wraight, K; Wyllie, K; Xie, Y; Xing, Z; Xu, Z; Yang, Z; Yao, Y; Yin, H; Yu, J; Yuan, X; Yushchenko, O; Zarebski, K A; Zavertyaev, M; Zhang, L; Zhang, Y; Zhang, Y; Zhelezov, A; Zheng, Y; Zhu, X; Zhukov, V; Zucchelli, S

    2017-05-12

    The production of J/ψ mesons in jets is studied in the forward region of proton-proton collisions using data collected with the LHCb detector at a center-of-mass energy of 13 TeV. The fraction of the jet transverse momentum carried by the J/ψ meson, z(J/ψ)≡p_{T}(J/ψ)/p_{T}(jet), is measured using jets with p_{T}(jet)>20  GeV in the pseudorapidity range 2.5<η(jet)<4.0. The observed z(J/ψ) distribution for J/ψ mesons produced in b-hadron decays is consistent with expectations. However, the results for prompt J/ψ production do not agree with predictions based on fixed-order nonrelativistic QCD. This is the first measurement of the p_{T} fraction carried by prompt J/ψ mesons in jets at any experiment.

  12. A Visual Study of Vortex Generator Jets

    NASA Astrophysics Data System (ADS)

    Compton, Debora A.; Stadnicki, John

    1997-11-01

    A jet which issues from a small hole in a flow surface, pitched and skewed relative to the crossflow, creates a single streamwise vortex which resembles the flow downstream of a half-delta-wing vortex generator. The term ``vortex generator jet'' (VGJ) has been used to describe such a flow. Investigators of jet-generated vortices have recognized their applicability to active control and their flexibility in terms of being activated and deactivated. We have installed a spanwise array of VGJ's in a turbulent boundary layer in the zero-pressure-gradient test section of the 12" × 36" boundary layer wind tunnel at Boston University. The Reynolds number based on jet diameter is in the range 4000 < Re < 10000. Our experimental investigations include flow visualization of a single pitched and skewed jet in crossflow, as well as wall shear stress measurements downstream of the array of jets. To capture still images of a cross-section of the jet flow, a light sheet formed by a pulsed Nd:YAG laser is used to illuminate smoke-tagged jet fluid. The wall shear stress measurements are made using an oil-film interferometry technique. Parameters varied include jet velocity and angles of jet pitch and skew.

  13. FEASIBILITY STUDY OF PONTOON BARGE WATER JET PROPULSION AND STEERAGE,

    DTIC Science & Technology

    A study was made to determine the feasibility of applying water jet propulsion to pontoon structures and to ascertain the state-of-the-art of a...suitable commercial pump and power unit. The results of the study indicate that a water jet propulsion system can be built which will have performance...surf operations because the water jet system has few operational problems in the surf zone. This improved performance carries with it a penalty in the

  14. Change in Body Mass Index, Weight, and Hot Flashes: A Longitudinal Analysis from the Midlife Women's Health Study

    PubMed Central

    Gallicchio, Lisa; Miller, Susan R.; Kiefer, Judith; Greene, Teresa; Zacur, Howard A.

    2014-01-01

    Abstract Background: The goals of this study were to examine the associations between body mass index (BMI), as well as BMI change and weight change, with midlife hot flashes. Methods: Data were analyzed from an ongoing 5-year cohort study of 631 midlife women (ages 45–54 years) recruited from Baltimore, Maryland, and its surrounding counties. Height and weight were measured at clinic visits conducted annually. Questionnaires administered at each clinic visit collected detailed data on hot flashes, including the severity and frequency, and other covariates. Data were analyzed using logistic regression and generalized estimated equation models, adjusting for potential confounders. Results: Among women enrolled in the study, 45.2% reported hot flashes and 32.0% were categorized as being obese (BMI ≥30 kg/m2) at baseline. At baseline, BMI was not significantly associated with ever experiencing hot flashes (BMI ≥30 versus <25 kg/m2: odds ratio [OR] 0.92; 95% confidence interval [CI]: 0.58, 1.15) or any of the other hot flashes outcomes (recent, frequent, or severe). In addition, no statistically significant associations between BMI, BMI change, or weight change, and the hot flash outcomes were observed in the longitudinal models (for example, any hot flashes: BMI ≥30 versus <25 kg/m2: OR 0.81; 95% CI: 0.56, 1.17). Conclusion: BMI, BMI change, and weight change during midlife were not related to hot flashes in this study. The data suggest that other factors, such as smoking habits, are more important in determining hot flashes risk during midlife. PMID:24341351

  15. Experimental study of elliptical jet from sub to supercritical conditions

    SciTech Connect

    Muthukumaran, C. K.; Vaidyanathan, Aravind

    2014-04-15

    The jet mixing at supercritical conditions involves fluid dynamics as well as thermodynamic phenomena. All the jet mixing studies at critical conditions to the present date have focused only on axisymmetric jets. When the liquid jet is injected into supercritical environment, the thermodynamic transition could be well understood by considering one of the important fluid properties such as surface tension since it decides the existence of distinct boundary between the liquid and gaseous phase. It is well known that an elliptical liquid jet undergoes axis-switching phenomena under atmospheric conditions due to the presence of surface tension. The experimental investigations were carried out with low speed elliptical jet under supercritical condition. Investigation of the binary component system with fluoroketone jet and N{sub 2} gas as environment shows that the surface tension force dominates for a large downstream distance, indicating delayed thermodynamic transition. The increase in pressure to critical state at supercritical temperature is found to expedite the thermodynamic transition. The ligament like structures has been observed rather than droplets for supercritical pressures. However, for the single component system with fluoroketone jet and fluoroketone environment shows that the jet disintegrates into droplets as it is subjected to the chamber conditions even for the subcritical pressures and no axis switching phenomenon is observed. For a single component system, as the pressure is increased to critical state, the liquid jet exhibits gas-gas like mixing behavior and that too without exhibiting axis-switching behavior.

  16. Experimental study of elliptical jet from sub to supercritical conditions

    NASA Astrophysics Data System (ADS)

    Muthukumaran, C. K.; Vaidyanathan, Aravind

    2014-04-01

    The jet mixing at supercritical conditions involves fluid dynamics as well as thermodynamic phenomena. All the jet mixing studies at critical conditions to the present date have focused only on axisymmetric jets. When the liquid jet is injected into supercritical environment, the thermodynamic transition could be well understood by considering one of the important fluid properties such as surface tension since it decides the existence of distinct boundary between the liquid and gaseous phase. It is well known that an elliptical liquid jet undergoes axis-switching phenomena under atmospheric conditions due to the presence of surface tension. The experimental investigations were carried out with low speed elliptical jet under supercritical condition. Investigation of the binary component system with fluoroketone jet and N2 gas as environment shows that the surface tension force dominates for a large downstream distance, indicating delayed thermodynamic transition. The increase in pressure to critical state at supercritical temperature is found to expedite the thermodynamic transition. The ligament like structures has been observed rather than droplets for supercritical pressures. However, for the single component system with fluoroketone jet and fluoroketone environment shows that the jet disintegrates into droplets as it is subjected to the chamber conditions even for the subcritical pressures and no axis switching phenomenon is observed. For a single component system, as the pressure is increased to critical state, the liquid jet exhibits gas-gas like mixing behavior and that too without exhibiting axis-switching behavior.

  17. A computational study of asymmetric glottal jet deflection during phonation

    PubMed Central

    Zheng, X.; Mittal, R.; Bielamowicz, S.

    2011-01-01

    Two-dimensional numerical simulations are used to explore the mechanism for asymmetric deflection of the glottal jet during phonation. The model employs the full Navier–Stokes equations for the flow but a simple laryngeal geometry and vocal-fold motion. The study focuses on the effect of Reynolds number and glottal opening angle with a particular emphasis on examining the importance of the so-called “Coanda effect” in jet deflection. The study indicates that the glottal opening angle has no substantial effect on glottal jet deflection. Deflection in the glottal jet is always preceded by large-scale asymmetry in the downstream portion of the glottal jet. A detailed analysis of the velocity and vorticity fields shows that these downstream asymmetric vortex structures induce a flow at the glottal exit which is the primary driver for glottal jet deflection. PMID:21476669

  18. A computational study of asymmetric glottal jet deflection during phonation.

    PubMed

    Zheng, X; Mittal, R; Bielamowicz, S

    2011-04-01

    Two-dimensional numerical simulations are used to explore the mechanism for asymmetric deflection of the glottal jet during phonation. The model employs the full Navier-Stokes equations for the flow but a simple laryngeal geometry and vocal-fold motion. The study focuses on the effect of Reynolds number and glottal opening angle with a particular emphasis on examining the importance of the so-called "Coanda effect" in jet deflection. The study indicates that the glottal opening angle has no substantial effect on glottal jet deflection. Deflection in the glottal jet is always preceded by large-scale asymmetry in the downstream portion of the glottal jet. A detailed analysis of the velocity and vorticity fields shows that these downstream asymmetric vortex structures induce a flow at the glottal exit which is the primary driver for glottal jet deflection.

  19. A Comprehensive Study on Energy Efficiency and Performance of Flash-based SSD

    SciTech Connect

    Park, Seon-Yeon; Kim, Youngjae; Urgaonkar, Bhuvan; Lee, Joonwon; Seo, Euiseong

    2011-01-01

    Use of flash memory as a storage medium is becoming popular in diverse computing environments. However, because of differences in interface, flash memory requires a hard-disk-emulation layer, called FTL (flash translation layer). Although the FTL enables flash memory storages to replace conventional hard disks, it induces significant computational and space overhead. Despite the low power consumption of flash memory, this overhead leads to significant power consumption in an overall storage system. In this paper, we analyze the characteristics of flash-based storage devices from the viewpoint of power consumption and energy efficiency by using various methodologies. First, we utilize simulation to investigate the interior operation of flash-based storage of flash-based storages. Subsequently, we measure the performance and energy efficiency of commodity flash-based SSDs by using microbenchmarks to identify the block-device level characteristics and macrobenchmarks to reveal their filesystem level characteristics.

  20. Using case studies to aid the development of a global flash flood prediction system

    NASA Astrophysics Data System (ADS)

    Hewson, Tim

    2016-04-01

    ECMWF (the European Centre for Medium range Weather Forecasts) is developing a global system for predicting flash floods. As its input this system will use forecast fields from the ECMWF global ensemble prediction system. Post-processing techniques convert the global model forecasts for gridboxes into probabilistic forecasts for rainfall at any point within those gridboxes. The post-processing techniques are key to the success of this system. They have been 'meteorologically informed'. This means that they rely on (a) a detailed physical understanding of rainfall generation mechanisms, and (b) study of individual cases of flash flooding. In (b) we want to ensure that the atmospheric structures that are believed to allow very large totals to accrue over small areas in a short time are present in real cases, and can be foreseen using output from the global model itself. This study will highlight what we understand the key factors to be, using case studies such as the devastating Tbilisi floods of June 2015, and physical reasoning, to illustrate. Furthermore, it will be shown that standard global model output does contain information that is pivotal in identifying when the atmospheric configuration has the potential to deliver flash floods, even though the raw rainfall output from the model is not, itself, extreme, and so would not, if taken literally, provide any warning.

  1. Laser flash photolysis study of paraquat reduction by photogenerated aromatic ketyl radicals and carbonyl triplets

    SciTech Connect

    Baral-Tosh, S.; Chattopadhyay, S.K.; Das, P.K.

    1984-03-29

    Results of a kinetic study based on 337.1-nm laser flash photolysis are presented for electron-transfer reactions with paraquat (PQ/sup 2 +/) as the oxidant for the triplets of a number of substituted benzophenones and acetophenones and the corresponding ketyl radicals. The ketyl radicals were generated from the ketone triplets by laser flash photolysis in the presence of excess of p-methoxyphenol. The electron-transfer rate constants (2 x 10/sup 8/-8 x 10/sup 9/ M/sup -1/ s/sup -1/) as well as the fractions (0.5-1.0) of the triplet quenching events that result in net reduction of PQ/sup 2 +/ correlate well with the electron-releasing nature of the substituents in the ketones. Quantitative data concerning the transient absorption spectra of substituted benzophenone triplets and diarylhydroxymenthyl radicals are also reported. 5 figures, 1 table.

  2. Some properties of negative cloud-to-ground flashes from observations of a local thunderstorm based on accurate-stroke-count studies

    NASA Astrophysics Data System (ADS)

    Zhu, Baoyou; Ma, Ming; Xu, Weiwei; Ma, Dong

    2015-12-01

    Properties of negative cloud-to-ground (CG) lightning flashes, in terms of number of strokes per flash, inter-stroke intervals and the relative intensity of subsequent and first strokes, were presented by accurate-stroke-count studies based on all 1085 negative flashes from a local thunderstorm. The percentage of single-stroke flashes and stroke multiplicity evolved significantly during the whole life cycle of the study thunderstorm. The occurrence probability of negative CG flashes decreased exponentially with the increasing number of strokes per flash. About 30.5% of negative CG flashes contained only one stroke and number of strokes per flash averaged 3.3. In a subset of 753 negative multiple-stroke flashes, about 41.4% contained at least one subsequent stroke stronger than the corresponding first stroke. Subsequent strokes tended to decrease in strength with their orders and the ratio of subsequent to first stroke peaks presented a geometric mean value of 0.52. Interestingly, negative CG flashes of higher multiplicity tended to have stronger initial strokes. 2525 inter-stroke intervals showed a more or less log-normal distribution and gave a geometric mean value of 62 ms. For CG flashes of particular multiplicity geometric mean inter-stroke intervals tended to decrease with the increasing number of strokes per flash, while those intervals associated with higher order strokes tended to be larger than those associated with low order strokes.

  3. Study of flash floods over some parts of Brazil using precipitation index

    NASA Astrophysics Data System (ADS)

    Souza, D.; de Souza, R. L. M.; Araujo, R.

    2016-12-01

    In Brazil, the main phenomena related to natural disasters are derived from the Earth's external dynamics such as floods and flash floods, landslides and storms, where the flash flood phenomenon causes the second highest number of victims, totaling more than 32% of deaths. Floods and flash floods are natural events often triggered by storms or long period of rains, usually associated with rising volume of rainfall on the watershed, leading the river to exceed its maximum. Whereas the occurrence of natural disasters in Brazil is increasing in recent years, the use of more accurate tools to aid in the monitoring of extreme hydrological events it becomes necessary, aiming to decrease the number of human and material losses. In this context, this paper aims to implement an early warning and monitoring system related to extreme precipitation values and hydrological processes. So, initially was studied flood events in the states of São Paulo and Paraná, aimed de determination of the characteristics of rainfall and atmosphere. Later it was used an indicator of precipitation based on the climatology, which indicates warning points on the drainage network related to extreme precipitation, which are obtained by remote sensing sources, for example, radar and satellite, and numerical weather prediction data of short and very short term. The results indicated that most of the flood events over the study area was related to rainfall of deep convection. The use of precipitation indicators also helped the monitoring and the early warning, showing this to be an excellent tool for applications related to flash floods.

  4. Benchmark studies of thermal jet mixing in SFRs using a two-jet model

    SciTech Connect

    Omotowa, O. A.; Skifton, R.; Tokuhiro, A.

    2012-07-01

    To guide the modeling, simulations and design of Sodium Fast Reactors (SFRs), we explore and compare the predictive capabilities of two numerical solvers COMSOL and OpenFOAM in the thermal jet mixing of two buoyant jets typical of the outlet flow from a SFR tube bundle. This process will help optimize on-going experimental efforts at obtaining high resolution data for V and V of CFD codes as anticipated in next generation nuclear systems. Using the k-{epsilon} turbulence models of both codes as reference, their ability to simulate the turbulence behavior in similar environments was first validated for single jet experimental data reported in literature. This study investigates the thermal mixing of two parallel jets having a temperature difference (hot-to-cold) {Delta}T{sub hc}= 5 deg. C, 10 deg. C and velocity ratios U{sub c}/U{sub h} = 0.5, 1. Results of the computed turbulent quantities due to convective mixing and the variations in flow field along the axial position are presented. In addition, this study also evaluates the effect of spacing ratio between jets in predicting the flow field and jet behavior in near and far fields. (authors)

  5. Feasibility study of acupuncture for reducing sleep disturbances and hot flashes in postmenopausal breast cancer survivors.

    PubMed

    Otte, Julie L; Carpenter, Janet S; Zhong, Xin; Johnstone, Peter A S

    2011-01-01

    The present study was a feasibility study of a tailored acupuncture intervention in postmenopausal breast cancer survivors (BCSs) reporting sleep disturbances and hot flashes. Objectiveswere (1) to describe patterns of acupuncture point use; (2) evaluate outcome expectancy, credibility, and acceptability relative to the intervention; and (3) evaluate patterns of symptom change over time. This was a single-group, nonrandomized, quasi-experimental 8-week study. Ten BCSs with both sleep disturbances and hot flashes were referred to any of 4 Midwestern community acupuncturists. Assessments were done at baseline (weeks 1, 2), during treatment (weeks 3, 4), and after treatment (weeks 5, 8). Acupuncture treatment was tailored to the individual by community acupuncturists and provided as 3 sessions within a 2-week period (weeks 3, 4). Patients wore a wrist actigraph during weeks 1, 2, 3, 4, 5, and 8 and a sternal skin conductance monitor for 24 consecutive hours during weeks 1, 2, 3, 4, 5, and 8. Subjective data were obtained by questionnaire at weeks 1, 2, 3, 4, 5, and 8. Women were a mean age of 53 years, with an average 6.75 years since diagnosis. A mean of 10 needles were used per session, with the most common points located in the lung or lung meridian. Breast cancer survivors had high expectancy that acupuncture would decrease their symptoms, believed it was a credible treatment, and felt it an acceptable form of treatment. Three significant patterns of symptom change were noted from baseline: an increase in the number of minutes it took to fall asleep after treatment (from week 5 to 8; P = .04), a decrease in the percentage of time awake after sleep onset from baseline to follow-up 2 (week 8; P = .05), and a decrease in the number of hot flashes from baseline to follow-up 1 (week 5; P = .02). Findings may be used by clinical nurse specialists to consider recommending acupuncture to improve sleep and reduce hot flashes in BCSs. Acupuncture treatment seems to be a

  6. Fundamental Study of Jet Noise Generation and Suppression. Volume I.

    DTIC Science & Technology

    representation for the sound field surrounding a jet is provided which yields a solution giving some insight to noise generating mechanisms. Finally, a general ... review and analysis is provided of the experimental studies of others concerning jet noise generation and suppression. Volume I contains the technical details and Volume II is a bibliography. (Author)

  7. Analytical study of twin-jet shielding

    NASA Technical Reports Server (NTRS)

    Gerhold, C. H.

    1980-01-01

    An analytical model a three-dimensional model, of twin-jet shielding, consisting of a point noise source impinging on a cylinder of heated flow in which the temperature and flow velocity are uniform across the cross-section is discussed. Wave equations are given for the regions outside the flow and within the flow cylinder and solutions are matched at the jet boundary under the conditions of continuity of pressure and continuity of the vortex sheet. The model was analyzed to identify mechanisms of transmission and diffraction which control sheilding in the shadow of the shielding jet. It was found that in the zone of the shadow region dominates, shielding is relatively insensitive to variations of such parameters as Mach Number and spacing ratio, but in the zone in which diffraction dominates; shielding is more sensitive to variations in Mach Number, jet temperature and spacing ratio.

  8. Diurnal rhythm and concordance between objective and subjective hot flashes: The Hilo Women’s Health Study

    PubMed Central

    Sievert, Lynnette L.; Reza, Angela; Mills, Phoebe; Morrison, Lynn; Rahberg, Nichole; Goodloe, Amber; Sutherland, Michael; Brown, Daniel E.

    2010-01-01

    Objective To test for a diurnal pattern in hot flashes in a multi-ethnic population living in a hot, humid environment. To examine rates of concordance between objective and subjective measures of hot flashes using ambulatory and laboratory measures. Methods Study participants aged 45–55 were recruited from the general population of Hilo, Hawaii. Women wore a Biolog hot flash monitor, kept a diary for 24-hours, and also participated in 3-hour laboratory measures (n=199). Diurnal patterns were assessed using polynomial regression. For each woman, objectively recorded hot flashes that matched subjective experience were treated as true positive readings. Subjective hot flashes were considered the standard for computing false positive and false negative readings. True positive, false positive, and false negative readings were compared across ethnic groups by chi-square analyses. Results Frequencies of sternal, nuchal and subjective hot flashes peaked at 15:00 ± 1 hour with no difference by ethnicity. Laboratory results supported the pattern seen in ambulatory monitoring. Sternal and nuchal monitoring showed the same frequency of true positive measures, but non-sternal electrodes picked up more false positive readings. Laboratory monitoring showed very low frequencies of false negatives. There were no ethnic differences in the frequency of true positive or false positive measures. Women of European descent were more likely to report hot flashes that were not objectively demonstrated (false negative measures). Conclusions The diurnal pattern and peak in hot flash occurrence in the hot humid environment of Hilo was similar to results from more temperate environments. Lack of variation in sternal vs. non-sternal measures, and in true positive measures across ethnicities suggests no appreciable effect of population variation in sweating patterns. PMID:20220538

  9. Randomised controlled trial comparing hypnotherapy versus gabapentin for the treatment of hot flashes in breast cancer survivors: a pilot study

    PubMed Central

    MacLaughlan David, Shannon; Salzillo, Sandra; Bowe, Patrick; Scuncio, Sandra; Malit, Bridget; Raker, Christina; Gass, Jennifer S; Granai, C O; Dizon, Don S

    2013-01-01

    Objectives To compare the efficacy of hypnotherapy versus gabapentin for the treatment of hot flashes in breast cancer survivors, and to evaluate the feasibility of conducting a clinical trial comparing a drug with a complementary or alternative method (CAM). Design Prospective randomised trial. Setting Breast health centre of a tertiary care centre. Participants 15 women with a personal history of breast cancer or an increased risk of breast cancer who reported at least one daily hot flash. Interventions Gabapentin 900 mg daily in three divided doses (control) compared with standardised hypnotherapy. Participation lasted 8 weeks. Outcome measures The primary endpoints were the number of daily hot flashes and hot flash severity score (HFSS). The secondary endpoint was the Hot Flash Related Daily Interference Scale (HFRDIS). Results 27 women were randomised and 15 (56%) were considered evaluable for the primary endpoint (n=8 gabapentin, n=7 hypnotherapy). The median number of daily hot flashes at enrolment was 4.5 in the gabapentin arm and 5 in the hypnotherapy arm. HFSS scores were 7.5 in the gabapentin arm and 10 in the hypnotherapy arm. After 8 weeks, the median number of daily hot flashes was reduced by 33.3% in the gabapentin arm and by 80% in the hypnotherapy arm. The median HFSS was reduced by 33.3% in the gabapentin arm and by 85% in the hypnotherapy arm. HFRDIS scores improved by 51.6% in the gabapentin group and by 55.2% in the hypnotherapy group. There were no statistically significant differences between groups. Conclusions Hypnotherapy and gabapentin demonstrate efficacy in improving hot flashes. A definitive trial evaluating traditional interventions against CAM methods is feasible, but not without challenges. Further studies aimed at defining evidence-based recommendations for CAM are necessary. Trial registration clinicaltrials.gov (NCT00711529). PMID:24022390

  10. Experimental study of a vertical jet in a vegetated crossflow.

    PubMed

    Ben Meftah, Mouldi; De Serio, Francesca; Malcangio, Daniela; Mossa, Michele; Petrillo, Antonio Felice

    2015-12-01

    Aquatic ecosystems have long been used as receiving environments of wastewater discharges. Effluent discharge in a receiving water body via single jet or multiport diffuser, reflects a number of complex phenomena, affecting the ecosystem services. Discharge systems need to be designed to minimize environmental impacts. Therefore, a good knowledge of the interaction between effluents, discharge systems and receiving environments is required to promote best environmental management practice. This paper reports innovative 3D flow velocity measurements of a jet discharged into an obstructed crossflow, simulating natural vegetated channel flows for which correct environmental management still lacks in literature. In recent years, numerous experimental and numerical studies have been conducted on vegetated channels, on the one hand, and on turbulent jets discharged into unvegetated crossflows, on the other hand. Despite these studies, however, there is a lack of information regarding jets discharged into vegetated crossflow. The present study aims at obtaining a more thorough understanding of the interaction between a turbulent jet and an obstructed crossflow. In order to achieve such an objective, a series of laboratory experiments was carried out in the Department of Civil, Environmental, Building Engineering and Chemistry of the Technical University of Bari - Italy. The physical model consists of a vertical jet discharged into a crossflow, obstructed by an array of vertical, rigid, circular and threaded steel cylinders. Analysis of the measured flow velocities shows that the array of emergent rigid vegetation significantly affects the jet and the ambient flow structures. It reduces the mean channel velocity, allowing the jet to penetrate higher into the crossflow. It significantly increases the transversal flow motion, promoting a major lateral spreading of the jet within the crossflow. Due to the vegetation array effects, the jet undergoes notable variations in its

  11. A Parametric Study of Jet Interactions with Rarefied Flow

    NASA Technical Reports Server (NTRS)

    Glass, C. E.

    2004-01-01

    Three-dimensional computational techniques, in particular the uncoupled CFD-DSMC of the present study, are available to be applied to problems such as jet interactions with variable density regions ranging from a continuum jet to a rarefied free stream. When the value of the jet to free stream momentum flux ratio approximately greater than 2000 for a sharp leading edge flat plate forward separation vortices induced by the jet interaction are present near the surface. Also as the free stream number density n (infinity) decreases, the extent and magnitude of normalized pressure increases and moves upstream of the nozzle exit. Thus for the flat plate model the effect of decreasing n (infinity) is to change the sign of the moment caused by the jet interaction on the flat plate surface.

  12. Flow visualisation studies on growth of area of deflected jets

    NASA Astrophysics Data System (ADS)

    Sivadas, V.; Pani, B. S.; Bütefisch, K. A.; Meier, G. E. A.

    Laser light sheet visualisation, coupled with image processing, was utilised to understand the effect of exit geometry on the integral properties of jets in cross flow. The study involved jets emanating from circular and rectangular nozzles of different aspect ratios deflected by a uniform free-stream. The investigation considers incompressible momentum jets with exit Reynolds number in the range of 4400-9200, the velocity ratios being 3.9, 5.9 and 7.8. In contrast to a deflected circular jet, those jets emanating from blunt configurations tend to have higher growth rates initially and are devoid of the horse-shoe or the bound vortex system in their cross section.

  13. An experimental study of jet exhaust simulation

    NASA Technical Reports Server (NTRS)

    Compton, W. B., III

    1975-01-01

    Afterbody drag predictions for jet aircraft are usually made experimentally with the jet exhaust flow simulated. The physical gas properties of the fluid used for the model jet exhaust can affect the accuracy of simulation of the airplane's jet exhaust plume. The effect of the accuracy of this simulation on afterbody drag was investigated by wind-tunnel tests with single engine model. In addition to unheated air as the exhaust gas, the decomposition products of three different concentrations of hydrogen peroxide were utilized. The air jet simulation consistently resulted in higher boattail drag than hydrogen peroxide simulation. The differences in drag for the various exhaust gases are attributed to different plume shapes and entrainment properties of the gases. The largest differences in drag due to exhaust gas properties were obtained for the combination of high transonic Mach numbers and high boattail angles. For these conditions, the current data indicate that the use of air to simulate a nonafterburning turbojet exhaust can result in an increase in afterbody amounting to 20 percent of the nonafterburning turbojet value.

  14. Fluorescence Imaging Study of Impinging Underexpanded Jets

    NASA Technical Reports Server (NTRS)

    Inman, Jennifer A.; Danehy, Paul M.; Nowak, Robert J.; Alderfer, David W.

    2008-01-01

    An experiment was designed to create a simplified simulation of the flow through a hole in the surface of a hypersonic aerospace vehicle and the subsequent impingement of the flow on internal structures. In addition to planar laser-induced fluorescence (PLIF) flow visualization, pressure measurements were recorded on the surface of an impingement target. The PLIF images themselves provide quantitative spatial information about structure of the impinging jets. The images also help in the interpretation of impingement surface pressure profiles by highlighting the flow structures corresponding to distinctive features of these pressure profiles. The shape of the pressure distribution along the impingement surface was found to be double-peaked in cases with a sufficiently high jet-exit-to-ambient pressure ratio so as to have a Mach disk, as well as in cases where a flow feature called a recirculation bubble formed at the impingement surface. The formation of a recirculation bubble was in turn found to depend very sensitively upon the jet-exit-to-ambient pressure ratio. The pressure measured at the surface was typically less than half the nozzle plenum pressure at low jet pressure ratios and decreased with increasing jet pressure ratios. Angled impingement cases showed that impingement at a 60deg angle resulted in up to a factor of three increase in maximum pressure at the plate compared to normal incidence.

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

    PubMed

    Ribblett, Alec Q; Poole, James S

    2016-06-30

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

  16. Visual readaptation after flash exposure under scotopic conditions. A study using optokinetic nystagmus as an indicator of visual perception.

    PubMed

    Wang, L

    1994-01-01

    The purpose of the present study was to establish a method for objective measurements of visual readaptation after flash exposures and to define a model for measurements. Influences of target direction, luminance and velocity on optokinetic nystagmus (OKN) were investigated under scotopic conditions. Visual readaptation was measured using OKN as an indicator of visual perception after exposure to a flash. The interval between the triggering of the flash and the reoccurrence of OKN was defined as the visual readaptation time (RAT). A Goldmann perimeter hemisphere was used for flash stimulation. A horizontally moving vertical grating projected inside the hemisphere was used as the OKN stimulus. Eye movements were recorded by DC electrooculography (EOG). The dependence of RAT on the dose of the flash, the wavelength of the flash and the luminance of the OKN target were investigated. The precision of the measurement method was studied. This includes the analysis of the variance due to the experimental occasions, the repeated exposures, the sexes of the subjects, the methods for recognition of OKN and the ways of visual adaptation before measurements. The contributions of retinal receptor and the neural activity to RAT were investigated by electroretinography (ERG). The influences of target direction and luminance on binocular motion perception and OKN as well as monocular OKN were examined at various target velocities. The dependence of the frequency and amplitude of eye jerks during monocular OKN on target luminance and velocity were also examined. It was found that RAT increases with increasing doses of the flash or decreasing luminance of the grating. RAT is most extended after flashes near 520 nm. RAT does not differ between experimental occasions, between a manual and a semi-automatic method for recognition of OKN, between the sexes and between goggle adaptation and ordinary dark adaptation. There is a reduction of RAT due to repeated flash exposures. The data

  17. A Correlation Study of Meteorological Dynamics and Thunderstorm Activity Leading to Terrestrial Gamma-Ray Flashes

    NASA Astrophysics Data System (ADS)

    Barnes, Daniel Edward

    The Terrestrial Gamma-ray Flash (TGF) was first discovered by Fishman et al. in 1994. The TGF is an emission of highly energetic radiation produced by or at least in close association with lightning. Fishman theorized that the TGFs were spawned at Sprite altitudes, however, Dwyer and Smith, utilizing detailed Monte Carlo calculations found the production level was within the troposphere, particularly in the altitude range of 15-21 km. This altitude places the TGF generating mechanism within thunderstorm cloud height. Current investigations tend to study the TGF itself in an attempt to isolate the production mechanism and production level while the thunderstorm characteristics have largely been ignored. The investigation into thunderstorms and their characteristics will utilize temporal and spatial coincident passes between the Ramatay High-energy Solar Spectroscopic Imager (RHESSI) and the Tropical Rainfall Measuring Mission (TRMM) in order to ascertain the bulk or footprint overlap fundamental storm properties of two types of events, the TGF generating thunderstorm (Yes case) and the non-TGF generating thunderstorm (Null case). Common components to each case are the presence of lightning during the coincident pass, spatial overlap of sub-satellite footprint within 500km and temporal difference of no more than one-hour. The defining difference is the Yes case has a RHESSI recorded TGF event while the Null case has no RHESSI recorded TGF event. Data presented will show that TGF storms possesses identifiable differences in the hydrometeor concentrations at different levels of the atmosphere. The Yes storm possesses elevated zero-degree isotherms, storm tops, increased occurrence of lower flash rates, low flash rate density and fairly uniform occurrence of lower optical radiance. These properties have statistically significant differences from their Null counterparts. It may be possible to identify potential TGF storms utilizing these storm characteristics and ground

  18. Does obesity increase the risk of hot flashes among midlife women?: a population-based study.

    PubMed

    Saccomani, Sylvio; Lui-Filho, Jeffrey Frederico; Juliato, Cassia Raquel; Gabiatti, Jose Roberto; Pedro, Adriana Orcesi; Costa-Paiva, Lucia

    2017-09-01

    To evaluate the association between vasomotor symptoms and obesity in climacteric women. We conducted a cross-sectional population-based study of 749 women aged 45 to 60 years. The dependent variable was intensity of menopausal symptoms evaluated by the menopause rating scale questionnaire. Independent variables were sociodemographic and clinical characteristics, and obesity evaluated by body mass index. There was no significant difference in the majority of clinical and sociodemographic characteristics between the body mass index groups. Obese women had less physical activity (P = 0.019) and a higher prevalence of hypertension (P < 0.001), diabetes (P = 0.002), urinary incontinence (P < 0.001), and urge incontinence (P = 0.0006). The total mean menopause rating scale score was 9.7. Scores for hot flashes increased progressively and were higher for participants with body mass index greater than 30 kg/m (P = 0.027). Joint and muscle pain scores also increased with increased body mass index (P < 0.001). Regarding urogenital symptoms, there was a significant difference in urinary problems only, which were more intense in obese women (body mass index >30 kg/m) (P < 0.0001). There was no significant difference in any psychological symptoms on the menopause rating scale. Factors associated with hot flash scores were higher body mass index, presence of urinary urgency, and vaginal dryness. We found that menopausal symptoms, including vasomotor, joint, and urinary symptoms, were related to obesity. Hot flashes were associated with higher body mass index, urinary urgency, and vaginal dryness. Understanding this relationship may contribute to the development of healthcare strategies aimed at minimizing the impact of obesity on several health issues of climacteric women.

  19. Cartographic Production for the FLaSH Map Study: Generation of Rugosity Grids, 2008

    USGS Publications Warehouse

    Robbins, Lisa L.; Knorr, Paul O.; Hansen, Mark

    2010-01-01

    Project Summary This series of raster data is a U.S. Geological Survey (USGS) Data Series release from the Florida Shelf Habitat Project (FLaSH). This disc contains two raster images in Environmental Systems Research Institute, Inc. (ESRI) raster grid format, jpeg image format, and Geo-referenced Tagged Image File Format (GeoTIFF). Data is also provided in non-image ASCII format. Rugosity grids at two resolutions (250 m and 1000 m) were generated for West Florida shelf waters to 250 m using a custom algorithm that follows the methods of Valentine and others (2004). The Methods portion of this document describes the specific steps used to generate the raster images. Rugosity, also referred to as roughness, ruggedness, or the surface-area ratio (Riley and others, 1999; Wilson and others, 2007), is a visual and quantitative measurement of terrain complexity, a common variable in ecological habitat studies. The rugosity of an area can affect biota by influencing habitat, providing shelter from elements, determining the quantity and type of living space, influencing the type and quantity of flora, affecting predator-prey relationships by providing cover and concealment, and, as an expression of vertical relief, can influence local environmental conditions such as temperature and moisture. In the marine environment rugosity can furthermore influence current flow rate and direction, increase the residence time of water in an area through eddying and current deflection, influence local water conditions such as chemistry, turbidity, and temperature, and influence the rate and nature of sedimentary deposition. State-of-the-art computer-mapping techniques and data-processing tools were used to develop shelf-wide raster and vector data layers. Florida Shelf Habitat (FLaSH) Mapping Project (http://coastal.er.usgs.gov/flash) endeavors to locate available data, identify data gaps, synthesize existing information, and expand our understanding of geologic processes in our dynamic

  20. Disaster management in flash floods in leh (ladakh): a case study.

    PubMed

    Gupta, Preeti; Khanna, Anurag; Majumdar, S

    2012-07-01

    On August 6, 2010, in the dark of the midnight, there were flash floods due to cloud burst in Leh in Ladakh region of North India. It rained 14 inches in 2 hours, causing loss of human life and destruction. The civil hospital of Leh was badly damaged and rendered dysfunctional. Search and rescue operations were launched by the Indian Army immediately after the disaster. The injured and the dead were shifted to Army Hospital, Leh, and mass casualty management was started by the army doctors while relief work was mounted by the army and civil administration. The present study was done to document disaster management strategies and approaches and to assesses the impact of flash floods on human lives, health hazards, and future implications of a natural disaster. The approach used was both quantitative as well as qualitative. It included data collection from the primary sources of the district collectorate, interviews with the district civil administration, health officials, and army officials who organized rescue operations, restoration of communication and transport, mass casualty management, and informal discussions with local residents. 234 persons died and over 800 were reported missing. Almost half of the people who died were local residents (49.6%) and foreigners (10.2%). Age-wise analysis of the deaths shows that the majority of deaths were reported in the age group of 25-50 years, accounting for 44.4% of deaths, followed by the 11-25-year age group with 22.2% deaths. The gender analysis showed that 61.5% were males and 38.5% were females. A further analysis showed that more females died in the age groups <10 years and ≥50 years. Disaster preparedness is critical, particularly in natural disasters. The Army's immediate search, rescue, and relief operations and mass casualty management effectively and efficiently mitigated the impact of flash floods, and restored normal life.

  1. Disaster Management in Flash Floods in Leh (Ladakh): A Case Study

    PubMed Central

    Gupta, Preeti; Khanna, Anurag; Majumdar, S

    2012-01-01

    Background: On August 6, 2010, in the dark of the midnight, there were flash floods due to cloud burst in Leh in Ladakh region of North India. It rained 14 inches in 2 hours, causing loss of human life and destruction. The civil hospital of Leh was badly damaged and rendered dysfunctional. Search and rescue operations were launched by the Indian Army immediately after the disaster. The injured and the dead were shifted to Army Hospital, Leh, and mass casualty management was started by the army doctors while relief work was mounted by the army and civil administration. Objective: The present study was done to document disaster management strategies and approaches and to assesses the impact of flash floods on human lives, health hazards, and future implications of a natural disaster. Materials and Methods: The approach used was both quantitative as well as qualitative. It included data collection from the primary sources of the district collectorate, interviews with the district civil administration, health officials, and army officials who organized rescue operations, restoration of communication and transport, mass casualty management, and informal discussions with local residents. Results: 234 persons died and over 800 were reported missing. Almost half of the people who died were local residents (49.6%) and foreigners (10.2%). Age-wise analysis of the deaths shows that the majority of deaths were reported in the age group of 25–50 years, accounting for 44.4% of deaths, followed by the 11–25-year age group with 22.2% deaths. The gender analysis showed that 61.5% were males and 38.5% were females. A further analysis showed that more females died in the age groups <10 years and ≥50 years. Conclusions: Disaster preparedness is critical, particularly in natural disasters. The Army's immediate search, rescue, and relief operations and mass casualty management effectively and efficiently mitigated the impact of flash floods, and restored normal life. PMID:23112446

  2. Flash Bulletin: Fireflies

    ERIC Educational Resources Information Center

    Brown, Debbie

    1984-01-01

    Explains the flashes of light emitted by fireflies as competition, species-specific code, species identification and mating behavior and ecology. Suggests activities to conduct to study the insects and their behavior. (ERB)

  3. Flash Bulletin: Fireflies

    ERIC Educational Resources Information Center

    Brown, Debbie

    1984-01-01

    Explains the flashes of light emitted by fireflies as competition, species-specific code, species identification and mating behavior and ecology. Suggests activities to conduct to study the insects and their behavior. (ERB)

  4. The Acupuncture on Hot Flashes Among Menopausal Women study: observational follow-up results at 6 and 12 months.

    PubMed

    Borud, Einar Kristian; Alraek, Terje; White, Adrian; Grimsgaard, Sameline

    2010-03-01

    The previously published Acupuncture on Hot Flashes Among Menopausal Women study compared the effectiveness of individualized acupuncture treatment plus self-care versus self-care alone on hot flashes and health-related quality of life in postmenopausal women. This article reports on the observational follow-up results at 6 and 12 months. The Acupuncture on Hot Flashes Among Menopausal Women study was a pragmatic, multicenter randomized controlled trial with two parallel arms, conducted in 2006 to 2007. The 267 participants were postmenopausal women experiencing, on average, 12.6 hot flashes per 24 h. The acupuncture group received 10 individualized acupuncture treatments during 12 weeks and advice on self-care, whereas the control group received only advice on self-care. Hot flash frequency and intensity (0-10 scale) and hours of sleep per night were registered in a diary. Health-related quality of life was assessed by the Women's Health Questionnaire. From baseline to 6 months, the mean reduction in hot flash frequency per 24 hours was 5.3 in the acupuncture group and 5.0 in the control group, a nonsignificant difference of 0.3. At 12 months, the mean reduction in hot flash frequency was 6.0 in the acupuncture group and 5.8 in the control group, a nonsignificant difference of 0.2. Differences in quality-of-life scores were not statistically significant at 6 and 12 months. The statistically significant differences between the study groups found at 12 weeks were no longer present at 6 and 12 months. Acupuncture can contribute to a more rapid reduction in vasomotor symptoms and increase in health-related quality of life in postmenopausal women but probably has no long-term effects.

  5. A Study of Mechanisms Producing Astrophysical Jets.

    DTIC Science & Technology

    1988-03-01

    Pacholczyk, Astrophysical Jets, D. Reidel, Dordrecht, 1983 6 Field, G. B., ed., The Redshift Controversy, Benjamin , Reading, 1973 7 F. D. Kuhn, ed...Feature Associated with the Seyfert Galaxy Markarian 915, Astrophysical Journal, around September, 1986 112 Narlikar, J. V., Noncosmological

  6. A study of real jet effects on the surface pressure distribution induced by a jet in a crossflow

    NASA Technical Reports Server (NTRS)

    Perkins, S. C., Jr.; Mendenhall, M. R.

    1981-01-01

    A study of jet exit profile, exit Mach number, swirl and turbulence level on jet-induced loadings for jets exhausting from a surface into a crossflow is presented. The importance of each of these real jet characteristics is assessed using available data. Where adequate surface pressure distribution data are available, a correlation method to predict surface pressure for a jet exhausting from an infinite flat plate is used either to attempt to develop a correlation based on the real jet characteristics or to model the effects of that characteristic. Data comparisons are presented for selected cases. Also, a summary of information on surface pressure distribution data for jet exhausting from flat plates into a subsonic crossflow is presented.

  7. 3-D LDA study of a rectangular jet

    NASA Technical Reports Server (NTRS)

    Morrison, Gerald L.; Tatterson, Gary B.; Swan, David H.

    1988-01-01

    The flow field of a rectangular jet with a 2:1 aspect ratio was studied at an axial Reynolds number of 100,000 (Mach number 0.09) using three-dimensional laser Doppler velocimetry. The flow field survey resulted in mean velocity vector field plots and contour plots of the Reynolds stress tensor components. This paper presents contour plots in the planes of the jet minor and major axes at different axial locations. These data contribute substantially to currently available data of jet flow fields and will provide a valuable database for three-dimensional modeling.

  8. Study of vertical plane turbulent jets and plumes

    NASA Astrophysics Data System (ADS)

    Ramaprian, B. R.; Chandrasekhara, M. S.

    1983-03-01

    Asymptotic, plane, vertical, turbulent plumes and nonbuoyant jets were studied. Simultaneous velocity and temperature were measured using frequency shifted, two component Laser Doppler anemometry (LDA), resistance thermometry and a high speed data acquisition system. Results obtained for two plumes with vastly different initial Richardson numbers indicate that both the plumes exhibit a nearly universal asymptotic behavior. The Richardson number of the asymptotic plume is a universal constant and is about 0.3. The mean velocity and temperature profiles in both jets and plumes are nearly Gaussian. It is found that turbulence levels in plumes are significantly higher than in jets.

  9. A Flash Flood Study on the Small Montaneous River Catchments in Western Romania

    NASA Astrophysics Data System (ADS)

    Győri, Maria-Mihaela; Haidu, Ionel; Humbert, Joël

    2013-04-01

    The present study focuses on flash flood modeling on several mountaneous catchments situated in Western Romania by the use of two methodologies, when rainfall and catchment characteristics are known. Hence, the Soil Conservation Service (SCS) Method and the Rational Method will be employed for the generation of the 1%, 2% and 10% historical flash flood hydrographs on the basis of data spanning from 1989-2009. The SCS Method has been applied on the three gauged catchments in the study area: Petris, Troas and Monorostia making use of the existing interconnection between GIS and the rainfall-runoff models. The DEM, soil data and land use preprocessing in GIS allowed a determination of the hydrologic parameters needed for the rainfall-runoff model, with special emphasis on determining the time of concentration, Lag time and the weighted Curve Number according to Antecedent Moisture Conditions II, adapted for the Romanian territory. HEC-HMS rainfall-runoff model (Hydrologic Engineering Center- Hydrologic Modeling System) facilitates the historical 1%, 2% and 10% flash flood hydrograph generation for the three afore mentioned watersheds. The model is calibrated against measured streamflow data from the three existing gauging stations. The results show a good match between the resulted hydrographs and the observed hydrographs under the form of the Peak Weighted Error RMS values. The hydrographs generated by surface runoff on the ungauged catchments in the area is based on an automation of a workflow in GIS, built with ArcGIS Model Builder graphical interface, as a large part of the functions needed were available as ArcGIS tools. The several components of this model calculate: the runoff depth in mm, the runoff coefficient, the travel time and finally the discharge module which is an application of the rational method, allowing the discharge computation for every cell within the catchment. The result consists of discharges for each isochrones that will be subsequently

  10. Pythia Jet Finding Study with Trento Backgrounds

    SciTech Connect

    Simpson, Joseph; Soltz, Ron

    2016-06-22

    We present results applying the Pythia SlowJet Finder to Pythia generated QCD and QED hard processes in the presence of simulated heavy ion backgrounds. The hard process events are generated with Pythia version 8.219 for √sNN=200 GeV proton-proton collisions and the backgrounds are generated by the Reduced Thickness Event-by-event Nuclear Topology model TRENTo for Au-Au collisions with a nucleon-nucleon cross-section of 4.23 fm2. The TRENTo model is used to calculate the initial entropy and ellipticity from which the total charged particle multiplicity and elliptic ow are determined. We report results in the form of event displays, total pT distributions, and fragmentation distributions for SlowJet applied to Pythia events with and without the simulated heavy ion backgrounds.

  11. A study of JET carbon impurity sources

    NASA Astrophysics Data System (ADS)

    Strachan, J. D.; Corrigan, G.; Stamp, M.; Spence, J.; Zacks, J.; JET-EFDA Contributors

    2009-06-01

    This paper compares experimental JET carbon and hydrogen visible emission to EDGE2D/NIMBUS calculations. The calculations themselves indicate that: (1) the integrated deuterium ionization in the SOL is proportional to the D α chordal integrated photon flux, (2) the carbon ionization in the SOL or the divertor is proportional to the calculated CIII chordal light, and (3) the ratio of line integrated photon fluxes from a vertical chord to a horizontal chord indicates whether the main chamber SOL content originated primarily from a wall source or from ion flow out of the divertor. Comparison was made to both inter-ELM H-Mode and L-Mode JET gas box divertor plasmas. The calculations infer that the experimental core contamination was caused by carbon sputtering arising primarily from the main chamber. The experimental, main chamber carbon yield was 1-4% in L-Mode and 5-10% in the inter-ELM H-Mode period.

  12. Submerged Gas Jet Penetration: A Study of Bubbling Versus Jetting and Side Versus Bottom Blowing in Copper Bath Smelting

    NASA Astrophysics Data System (ADS)

    Kapusta, Joël P. T.

    2017-06-01

    Although the bottom blowing ShuiKouShan process has now been widely implemented in China, in both lead and copper smelters, some doubts, questions, and concerns still seem to prevail in the metallurgical community outside China. In the author's opinion, part of these doubts and concerns could be addressed by a better general understanding of key concepts of submerged gas injection, including gas jet trajectory and penetration, and the concept, application, and benefits of sonic injection in jetting regime. To provide some answers, this article first offers a discussion on the historical developments of the theory and mathematical characterization of submerged gas jet trajectory, including the proposed criteria for the transition from bubbling to jetting regime and the application of the Prandtl-Meyer theory to submerged gas jets. A second part is devoted to a quantitative study of submerged gas jet penetration in copper bath smelting, including a comparison between bubbling and jetting regimes, and side versus bottom blowing. In the specific cases studied, the calculated gas jet axis trajectory length in jetting regime is 159 cm for bottom blowing, whereas it varies between 129 and 168 cm for side blowing for inclination angles of +18° to -30° to the horizontal. This means that side blowing in the jetting regime would provide a deeper penetration and longer gas jet trajectory than generally obtained by conventional bath smelting vessels such as the Noranda and Teniente reactors. The theoretical results of this study do corroborate the successful high-intensity practice of the slag make converting process at Glencore Nickel in Canada that operates under high oxygen shrouded injection in the jetting regime, and this would then suggest that retrofitting conventional low-pressure, side-blowing tuyeres of bath smelting and converting reactors with sonic injectors in jetting regime certainly appears as a valuable option for process intensification with higher oxygen

  13. Jet shielding of jet noise

    NASA Technical Reports Server (NTRS)

    Simonich, J. C.; Amiet, R. K.; Schlinker, R. H.

    1986-01-01

    An experimental and theoretical study was conducted to develop a validated first principle analysis for predicting the jet noise reduction achieved by shielding one jet exhaust flow with a second, closely spaced, identical jet flow. A generalized fuel jet noise analytical model was formulated in which the acoustic radiation from a source jet propagates through the velocity and temperature discontinuity of the adjacent shielding jet. Input variables to the prediction procedure include jet Mach number, spacing, temperature, diameter, and source frequency. Refraction, diffraction, and reflection effects, which control the dual jet directivity pattern, are incorporated in the theory. The analysis calculates the difference in sound pressure level between the dual jet configuration and the radiation field based on superimposing two independent jet noise directivity patterns. Jet shielding was found experimentally to reduce noise levels in the common plane of the dual jet system relative to the noise generated by two independent jets.

  14. Fluorescence imaging study of free and impinging supersonic jets: Jet structure and turbulent transition

    NASA Astrophysics Data System (ADS)

    Inman, Jennifer Ann

    A series of experiments into the behavior of underexpanded jet flows has been conducted at NASA Langley Research Center. This work was conducted in support of the Return to Flight effort following the loss of the Columbia. The tests involved simulating flow through a hypothetical breach in the leading edge of the Space Shuttle Orbiter along its reentry trajectory, with the goal of generating a data set with which other researchers can test and validate computational modeling tools. Two nozzles supplied with high-pressure gas were used to generate axisymmetric underexpanded jets exhausting into a low-pressure chamber. These nozzles had exit Mach numbers of 1 and 2.6. Reynolds numbers based on nozzle exit conditions ranged from about 200 to 35,000, and nozzle exit-to-ambient jet pressure ratios ranged from about 1 to 37. Both free and impinging jets were studied, with impingement distances ranging from 10 to 40 nozzle diameters, and impingement angles of 45°, 60°, and 90°. For the majority of cases, the jet fluid was a mixture of 99.5% nitrogen seeded with 0.5% nitric oxide (NO). Planar laser-induced fluorescence (PLIF) of NO was used to non-intrusively visualize the flow with a temporal resolution on the order of lets. PLIF images were used to identify and measure the location and size of flow structures. PLIF images were further used to identify unsteady jet behavior in order to quantify the conditions governing the transition to turbulent flow. This dissertation will explain the motivation behind the work, provide details of the laser system and test hardware components, discuss the theoretical aspects of laser-induced fluorescence, give an overview of the spectroscopy of nitric oxide, and summarize the governing fluid mechanical concepts. It will present measurements of the size and location of flow structures, describe the basic mechanisms and origins of unsteady behavior in these flows, and discuss the dependence of such behavior on particular flow

  15. Experimental study of self magnetic pinch diode as flash radiography source at 4 megavolt

    SciTech Connect

    Etchessahar, Bertrand; Bicrel, Béatrice; Cassany, Bruno; Desanlis, Thierry; Voisin, Luc; Maisonny, Rémi; Toury, Martial; Hourdin, Laurent; Cartier, Frédéric; Cartier, Stéphanie; D'Almeida, Thierry; Delbos, Christophe; Garrigues, Alain; Plouhinec, Damien; Ritter, Sandra; Sol, David; Zucchini, Frédéric; Caron, Michel

    2013-10-15

    The Self Magnetic Pinch (SMP) diode is a potential high-brightness X-ray source for high voltage generators (2–10 MV) that has shown good reliability for flash radiography applications [D. D. Hinchelwood et al., “High power self-pinch diode experiments for radiographic applications” IEEE Trans. Plasma Sci. 35(3), 565–572 (2007)]. We have studied this diode at about 4 MV, driven by the ASTERIX generator operated at the CEA/GRAMAT [G. Raboisson et al., “ASTERIX, a high intensity X-ray generator,” in Proceedings of the 7th IEEE Pulsed Power Conference (1989), pp. 567–570]. This generator, made up of a capacitor bank and a Blumlein line, was initially designed to test the behavior of electronic devices under irradiation. In our experiments, the vacuum diode is modified in order to set up flash radiographic diodes. A previous set of radiographic experiments was carried out on ASTERIX with a Negative Polarity Rod Pinch (NPRP) diode [B. Etchessahar et al., “Study and optimization of negative polarity rod pinch diode as flash radiography source at 4.5 MV,” Phys. Plasmas 19(9), 093104 (2012)]. The SMP diode which is examined in the present study provides an alternative operating point on the same generator and a different radiographic performance: 142 ± 11 rad at 1 m dose (Al) for a 3.46 ± 0.42 mm spot size (1.4× FWHM of the LSF). This performance is obtained in a reproducible and robust nominal configuration. However, several parametric variations were also tested, such as cathode diameter and anode/cathode gap. They showed that an even better performance is accessible after optimization, in particular, a smaller spot size (<3 mm). Numbers of electrical, optical, and X-ray diagnostics have been implemented in order to gain more insight in the diode physics and to optimize it further. For the first time in France, visible and laser imaging of the SMP diode has been realized, from a radial point of view, thus, providing key information on the electrode

  16. Experimental study of self magnetic pinch diode as flash radiography source at 4 megavolt

    NASA Astrophysics Data System (ADS)

    Etchessahar, Bertrand; Maisonny, Rémi; Toury, Martial; Hourdin, Laurent; Bicrel, Béatrice; Cassany, Bruno; Desanlis, Thierry; Voisin, Luc; Cartier, Frédéric; Cartier, Stéphanie; D'Almeida, Thierry; Delbos, Christophe; Garrigues, Alain; Plouhinec, Damien; Ritter, Sandra; Sol, David; Zucchini, Frédéric; Caron, Michel

    2013-10-01

    The Self Magnetic Pinch (SMP) diode is a potential high-brightness X-ray source for high voltage generators (2-10 MV) that has shown good reliability for flash radiography applications [D. D. Hinchelwood et al., "High power self-pinch diode experiments for radiographic applications" IEEE Trans. Plasma Sci. 35(3), 565-572 (2007)]. We have studied this diode at about 4 MV, driven by the ASTERIX generator operated at the CEA/GRAMAT [G. Raboisson et al., "ASTERIX, a high intensity X-ray generator," in Proceedings of the 7th IEEE Pulsed Power Conference (1989), pp. 567-570]. This generator, made up of a capacitor bank and a Blumlein line, was initially designed to test the behavior of electronic devices under irradiation. In our experiments, the vacuum diode is modified in order to set up flash radiographic diodes. A previous set of radiographic experiments was carried out on ASTERIX with a Negative Polarity Rod Pinch (NPRP) diode [B. Etchessahar et al., "Study and optimization of negative polarity rod pinch diode as flash radiography source at 4.5 MV," Phys. Plasmas 19(9), 093104 (2012)]. The SMP diode which is examined in the present study provides an alternative operating point on the same generator and a different radiographic performance: 142 ± 11 rad at 1 m dose (Al) for a 3.46 ± 0.42 mm spot size (1.4× FWHM of the LSF). This performance is obtained in a reproducible and robust nominal configuration. However, several parametric variations were also tested, such as cathode diameter and anode/cathode gap. They showed that an even better performance is accessible after optimization, in particular, a smaller spot size (<3 mm). Numbers of electrical, optical, and X-ray diagnostics have been implemented in order to gain more insight in the diode physics and to optimize it further. For the first time in France, visible and laser imaging of the SMP diode has been realized, from a radial point of view, thus, providing key information on the electrode plasmas evolution

  17. Jet Noise Reduction by Microjets - A Parametric Study

    NASA Technical Reports Server (NTRS)

    Zaman, K. B. M. Q.

    2010-01-01

    The effect of injecting tiny secondary jets (microjets ) on the radiated noise from a subsonic primary jet is studied experimentally. The microjets are injected on to the primary jet near the nozzle exit with variable port geometry, working fluid and driving pressure. A clear noise reduction is observed that improves with increasing jet pressure. It is found that smaller diameter ports with higher driving pressure, but involving less thrust and mass fraction, can produce better noise reduction. A collection of data from the present as well as past experiments is examined in an attempt to correlate the noise reduction with the operating parameters. The results indicate that turbulent mixing noise reduction, as monitored by OASPL at a shallow angle, correlates with the ratio of jet to primary jet driving pressures normalized by the ratio of corresponding diameters (p d /pjD). With gaseous injection, the spectral amplitudes decrease at lower frequencies while an increase is noted at higher frequencies. It is apparent that this amplitude crossover is at least partly due to shock-associated noise from the underexpanded jets themselves. Such crossover is not seen with water injection since the flow in that case is incompressible and there is no shock-associated noise. Centerline velocity data show that larger noise reduction is accompanied by faster jet decay as well as significant reduction in turbulence intensities. While a physical understanding of the dependence of noise reduction on p d /pjD remains unclear, given this correlation, an analysis explains the observed dependence of the effect on various other parameters.

  18. Multiple-laser flash shadowgraphy system for terminal studies of small-caliber projectiles

    NASA Astrophysics Data System (ADS)

    Kalonia, R. C.; Mitra, Gautam; Singh, G. S.; Varma, R. K.; Singh, Manpreet; Singh, Manjit; Sethi, V. S.; Yadav, M. S.

    2010-06-01

    A multiple-laser flash shadowgraphy system has been innovatively designed and developed to study the terminal effects of projectiles. The system has been designed based on modulated laser diodes operated at low voltage and current. In order to study the ballistics effects of small arms, an exposure time of the order of a few hundreds ns and a delay time of the order of a few tens of μs are needed. An ultrashort pulse generator has been developed to provide the exposure and delay time pulses. The developed system has been integrated with a field lens assembly and camera assembly. To record the shadowgraphs, a target is placed near the center of the field lens and a bullet is fired from a fixed gun. The system is described, and experimental results and conclusions are reported.

  19. p-Nitrobenzenesulfenate esters as precursors for laser flash photolysis studies of alkyl radicals.

    PubMed

    Newcomb, Martin; Daublain, Pierre; Horner, John H

    2002-11-29

    A series of p-nitrobenzenesulfenate esters was used in laser flash photolysis (LFP) studies to generate alkoxyl radicals that fragmented to give the (2,2-diphenylcyclopropyl)methyl radical. Rate constants for the beta-scission reactions increased as a function of the carbonyl compound produced in the fragmentation reaction in the order CH2O < MeCHO < Me2CO < PhCHO < Ph2CO and increased with increasing solvent polarity. For alkoxyl radicals that fragment to produce benzaldehyde and benzophenone, the beta-scission reactions are faster than 1,5-hydrogen atom abstractions when the incipient carbon radical is as stable as a secondary alkyl radical, and this entry to carbon radicals can be used in LFP kinetic studies.

  20. A study of jet energy measurement at CDF

    SciTech Connect

    1998-09-01

    This thesis describes the effort being made to improve the Jet Energy Reconstruction as performed by the CDF international collaboration at the Tevatron collider. This experiment studies proton-antiproton interactions at a center of mass energy of 1.8 TeV. During the three years data taking period Run 1, from 1992 to 1995 the CDF experiment collected an amount of data corresponding to a total integrated luminosity of 110 pb{sup -1}. One of the major results obtained analyzing this data sample is the discovery of the top quark. In the year 2000 a new period of data taking, Run 11, will start with a higher luminosity and a slightly higher center of mass energy giving us the chance to explore high energy physics even deeper. In preparation of this new run several upgrades are being made to adapt the CDF detector to the high luminosity foreseen and to improve its capabilities. Many signatures requested to trigger the detector aim at signaling a quark or a gluon in the final state. Unfortunately we are not able to measure quarks as free particles because they undergo a fragmentation process when turning into jets of particles. Thus it is of key importance to build up algorithms which reconstruct the energy of the initial parton starting from the jet informations. The description of the algorithm adopted till now will be given as an introduction to the new method being developed, that will be the main subject of this thesis. In Chapter I we will give a theoretical introduction on strong interactions to describe the mechanism to produce hadronic jets. In Chapter 2 we will describe some results from the experiment where the reconstruction of hadronic jets was important. Here we will also mention some important results which we think we can obtain during new the data taking period. We will give particular emphasis to those processes where an improved jet energy measured would bring to better results. In Chapter 3 we will give a description of the CDF detector including some

  1. [Left ventricular function, volumes, and mass in MRI studies using SFPP versus FLASH sequences in an animal model.].

    PubMed

    Bastarrika, G; Gavira, J J; Abizanda, G; Alonso-Burgos, A; Ilzarbe, M; Prósper, F

    2009-01-01

    To compare the accuracy of two cine-gradient-echo sequences to quantify left ventricular function, volumes, and mass in an animal model. We studied ten Gottingen miniature pigs (seven male, three female; mean weight 49.8+/-10.65kg; range: 35-65kg) with a 1.5 Tesla MRI scanner using free-breathing SSFP and FLASH sequences. We used 8-mm short-axis images to estimate left ventricular ejection fraction (EF), volumes (end-diastolic (EDV), end-systolic (ESV), and stroke volume (SV)), mass, and signal-to-noise ratio (SNR) on SSFP and FLASH sequences. We analyzed the correlation and concordance of the two sequences for each variable. Using the SSFP sequence, the mean estimated EF was 77.35+/-3.13%; mean EDV 61.55+/-8.64ml; mean ESV 13.83+/-1.92ml; mean SV 47.72+/-7.78ml; and mean myocardial mass 75.87+/-11.44g. Using the FLASH sequence, the mean EF was 81.87+/-2.22%; mean EDV 55.4+/-8.08ml; mean ESV 10.03+/-1.87ml; mean SV 45.38+/-6.83ml; and mean myocardial mass 87.74+/-15.21g. The correlation between SSFP and FLASH to quantify EDV, SV, and myocardial mass was excellent (r>0.8) and moderate (r>0.4) for quantifying ESV and EF. The SNR in the SSFP sequence was significantly higher than in the FLASH sequence (mean difference 120.94+/-42.94). In the SSFP sequence, ventricular volumes are slightly higher and ventricular mass is slightly lower than in the FLASH sequence, probably because of the higher SNR on SSFP sequences.

  2. Studying the hydro-meteorological extremes. The benefits from the European Flash Flood research oriented HYDRATE project.

    NASA Astrophysics Data System (ADS)

    Tsanis, Ioannis K.; Koutroulis, Aristeidis G.; Daliakopoulos, Ioannis N.; Grillakis, Emmanouil G.

    2010-05-01

    The present paper summarizes the advances of flash flood research for the Greek case study, within the frame of HYDRATE EC funded project. As a first step, a collation of homogenous primary data on flash floods occurred in Greece based on various data sources resulted in 21 documented events, enriching the HYDRATE database. Specific major events were selected for further detailed data collation and analysis. A common intensive post event field survey was conducted by various researchers with different skills and experience, in order to document the 18th of September 2007, Western Slovenia flash flood event. The observation strategy and the lessons learned during this campaign were applied successfully for surveying an event in Crete. Two flash flood events occurred in Crete were selected for detailed analysis, the 13th of January 1994 event occurred in Giofiros basin and the 17th of October 2006 event occurred in Almirida basin. Several techniques, like distributed rainfall-runoff modelling, hydraulic modelling, indirect and empirical peak discharge estimation, were applied for the understanding of the dominant flash flood processes and the effect of initial conditions on peak discharge. In a more general framework, the seasonality of the hydrometeorologic characteristics of floods that occurred in Crete during the period 1990-2007 and the atmospheric circulation conditions during the flood events were examined. During the three and a half years research period, many lessons have learnt from a fruitful collaboration among the project partners. HYDRATE project improved the scientific basis of flash flood research and provided research knowledge on flood risk management.

  3. Understanding charge transfer processes on metal oxides: a laser-flash-photolysis study

    NASA Astrophysics Data System (ADS)

    Sieland, Fabian; Schneider, Jenny; Lippmann, Thorsten; Bahnemann, Detlef W.

    2016-09-01

    In the focus of this study, mixtures of commercially available TiO2 powders were created and their photocatalytic activity concerning the acetaldehyde degradation in the gas phase was tested. Further, the lifetime of the photogenerated charge carriers was analyzed by Laser-Flash-Photolysis-Spectroscopy. The acetaldehyde degradation experiments of the mixed powders lead to positive and negative deviations from the expected weighted mean. Nevertheless, their photocatalytic activity could be correlated with the lifetime of the charge carriers. A longer charge carrier lifetime at ambient conditions correlated with a lower fractional conversion of acetaldehyde. The advantageous activities of the samples were associated with a charge transfer reaction between larger and smaller particles comparable to the antenna mechanism.1

  4. A Novel Animal Model to Study Hot Flashes: No Effect of GnRH

    PubMed Central

    Albertson, Asher J.; Skinner, Donal C.

    2009-01-01

    Menopausal hot flushes compromise the quality of life for the majority of women. The physiological mechanisms underlying hot flushes remain poorly understood and the absence of an animal model to investigate hot flushes hinders investigations in this field. We have developed the sheep as a model to study peripheral skin temperature changes. Subjecting sheep to fever-inducing treatments with lipopolysaccharide, a significant (P<0.01) change in ear skin temperature was observed. As a strong correlation between luteinizing hormone pulses and hot flushes has previously been reported, we then determined whether intravenous gonadotropin-releasing hormone (GnRH), at doses sufficient to elevate CSF GnRH concentrations, could modulate ear skin temperature. No effect was observed, suggesting that GnRH per se dose not play a role in the etiology of hot flashes. PMID:19512948

  5. Simplification approach to detect urban areas vulnerable to flash floods using GIS: a case study Warsaw

    NASA Astrophysics Data System (ADS)

    Wicht, Marzena; Osińska-Skotak, Katarzyna

    2016-04-01

    The aim of this study is to develop a consistent methodology to determine urban areas that are particularly vulnerable to the effects of torrential rains. They are, as a result of climate change, more and more prevalent in the temperate climate, usually spring - summer from mid-May to late August - and involve the risk of flash floods. In recent years, the increase in the incidence of such phenomena is noticeable throughout the whole Europe. It is assumed that through the analysis of environmental and infrastructural conditions, using the developed methodology, it is possible to determine areas vulnerable to flooding due to torrential rains. This may lead to a better management, quicker response in case of a phenomenon, and even to take measures to prevent the occurrence of adverse effects of torrential rains (for instance modernization of the urban drainage system and development of methods to get rid of rapidly collected water). Designation of areas particularly vulnerable to the effects of heavy rains can be achieved by adapting hydrological models, but they require an appropriate adjustment and highly accurate input data: (based on spot or radar measurements of precipitation, land cover, soil type, humidity, wind speed, vegetation species in a given area, growing season, the roughness and porosity of the cover and soil moisture) but such detailed data are generally hard to obtain or not available for less developed areas. It could also be achieved by performing spatial analysis in GIS, which is a more simplified form of modelling, but it gives results more quickly and the methodology can be adapted to the commonly available data. A case study of Warsaw's district Powiśle has been undertaken for three epochs - from 2008 to 2010 and areas, that are particularly vulnerable to the effects of flash floods and heavy rains, have been designated.

  6. Study on the engine oil's wear based on the flash point

    NASA Astrophysics Data System (ADS)

    Niculescu, R.; Iorga-Simăn, V.; Trică, A.; Clenci, A.

    2016-08-01

    Increasing energy performance of internal combustion engines is largely influenced by frictional forces that arise between moving parts. Thus, in this respect, the nature and quality of the engine oil used is an important factor. Equally important is the effect of various engine injection strategies upon the oil quality. In other words, it's of utmost importance to maintain the quality of engine oil during engine's operation. Oil dilution is one of the most common causes that lead to its wear, creating lubrication problems. Moreover, at low temperatures operating conditions, the oil dilution with diesel fuel produces wax. When starting the engine, this may lead to lubrication deficiencies and even oil starvation with negative consequences on the engine mechanism parts wear (piston, rings and cylinders) but also crankcase bearings wear.Engine oil dilution with diesel fuel have several causes: wear of rings and/or injectors, late post-injection strategy for the sake of particulate filter regeneration, etc.This paper presents a study on the degree of deterioration of engine oils as a result of dilution with diesel fuel. The analysed oils used for this study were taken from various models of engines equipped with diesel particulate filter. The assessment is based on the determination of oil flash point and dilution degree using the apparatus Eraflash produced by Eralytics, Austria. Eraflash measurement is directly under the latest and safest standards ASTM D6450 & D7094), which are in excellent correlation with ASTM D93 Pensky - Martens ASTM D56 TAG methods; it uses the Continuous Closed Cup method for finding the Flash Point (CCCFP).

  7. Electron transfer kinetics in purified reaction centers from the green sulfur bacterium Chlorobium tepidum studied by multiple-flash excitation.

    PubMed

    Kusumoto, N; Sétif, P; Brettel, K; Seo, D; Sakurai, H

    1999-09-14

    Reaction center preparations from the green sulfur bacterium Chlorobium tepidum, which contain monoheme cytochrome c, were studied by flash-absorption spectroscopy in the near-UV, visible, and near-infrared regions. The decay kinetics of the photooxidized primary donor P840(+), together with the amount of photooxidized cytochrome c, were analyzed along a series of four flashes spaced by 1 ms: 95% of the P840(+) was reduced by cytochrome c with a t(1/2) of approximately 65 micros after the first flash, 80% with a t(1/2) of approximately 100 micros after the second flash, and 23% with a t(1/2) of approximately 100 micros after the third flash; after the fourth flash, almost no cytochrome c oxidation occurred. The observed rates, the establishment of redox equilibrium after each flash, and the total amount of photooxidizable cytochrome c are consistent with the presence of two equivalent cytochrome c molecules per photooxidizable P840. The data are well fitted assuming a standard free energy change DeltaG degrees of -53 meV for electron transfer from one cytochrome c to P840(+), DeltaG degrees being independent of the oxidation state of the other cytochrome c. These observations support a model with two monoheme cytochromes c which are symmetrically arranged around the reaction center core. From the ratio of menaquinone-7 to the bacteriochlorophyll pigment absorbing at 663 nm, it was estimated that our preparations contain 0.6-1.2 menaquinone-7 molecules per reaction center. However, no transient signal due to menaquinone could be observed between 360 and 450 nm in the time window from 10 ns to 4 micros. No recombination reaction between the primary partners P840(+) and A(0)(-) could be detected under normal conditions. Such a recombination was observed (t(1/2) approximately 19 ns) under highly reducing conditions or after accumulation of three electrons on the acceptor side during a series of flashes, showing that the secondary acceptors can stabilize three electrons

  8. Kinetic studies of the reaction between pesticides and hydroxyl radical generated by laser flash photolysis.

    PubMed

    Gozzi, Fábio; Oliveira, Silvio C; Dantas, Renato F; Silva, Volnir O; Quina, Frank H; Machulek, Amilcar

    2016-03-30

    Due to contamination of the environment by pesticides and their mishandling, there is the need for treatment of contaminated sites and correct disposal of materials containing them. Thus, studies with advanced oxidation processes are expanding and can determine the rate constant of the hydroxyl radical with organic compounds of great importance in environmental contamination. In this context, the use of laser flash photolysis has been shown to be viable for the determination of these constants. The reaction rate constants of different pesticides with HO(•) in degassed acetonitrile have been determined. They were 1.6 × 10(9)  M(-1)  s(-1), 0.6 × 10(9)  M(-1)  s(-1), 1.2 × 10(9)  M(-1)  s(-1), 2.4 × 10(9)  M(-1)  s(-1) and 2.2 × 10(9)  M(-1)  s(-1) for the pesticides carbaryl, propoxur, fenoxycarb, ethoxysulfuron and chlorimuron-ethyl, respectively. These values are about an order of magnitude smaller than the diffusion controlled rate and correlate with the relative rates of disappearance of the pesticides in the photo-Fenton reaction in water. The correlation of the relative rate constants determined by laser flash photolysis with the relative rates of photo-Fenton degradation of the pesticides is compelling evidence for the participation of the hydroxyl radical in the degradation of these pesticides in the latter system. © 2015 Society of Chemical Industry.

  9. Nanosecond flash studies of reduction of benzophenone by aliphatic amines. Quantum yields and kinetic isotope effects

    SciTech Connect

    Inbar, S.; Linschitz, H.; Cohen, S.G.

    1981-03-11

    Nanosecond flash photolysis, steady irradiation, and deuterium substitution studies have been carried out on solutions of benzophenone with added reductants. Quantum yields (phi/sub ketyl/) for reduction in benzene of benzophenone triplet to ketyl radical, based on phi = 2 for benzhydrol (I), were approx. 1 for cyclohexane (II), tert-butylamine (III), 2-aminobutane (IV), cyclohexylamine (V), di-n-propylamine (VI), and triethylamine (VII), approx. 0.7 for 1,4-diazabicyclo(2.2.2)octane (VIII), and approx. 0 for tert-butyl alcohol (IX). Thus, quenching, without radical formation by H abstraction from N and/or ..cap alpha..-C, does not occur with common aliphatic amines but does with Dabco (VIII). The latter quenching is markedly increased by small additions of acetonitrile; the flash spectrum from this compound indicates formation of a triplet amine CT complex or radical ion pair. Triplet-reductant interaction rate constants, k/sur ir/, are high for the amines (approx. 10/sup 8/-10/sup 9/ M/sup -1/ s/sup -1/) but also show significant deuterium kinetic isotope effects: 1.9 with III-N-d/sub 2/; 1.4 with IV-N-d/sub 2/; 1.2-1.3 with IV-..cap alpha..-C-d. It is proposed that k/sub ir/ measures H atom abstraction, favored in the transition state by an initial charge-transfer interaction. Overall steady irradiation quantum yields of reduction by amines, phi/sub Red/, are much lower than phi/sub ketyl/. This is attributed to disproportionationreactions of ketyl and alkylaminyl radicals for primary and secondary amines, and, possibly, aminoalkyl radicals for tertiary amines. In the case of tert-butylamine, the rate constant for disproportionation is obtained from the decay kinetics of ketyl radical and leads to phi/sub Red/ in agreement with that directly measured.

  10. Experimental study of a two-phase surface jet

    NASA Astrophysics Data System (ADS)

    Perret, Matias; Esmaeilpour, Mehdi; Politano, Marcela S.; Carrica, Pablo M.

    2013-04-01

    Results of an experimental study of a two-phase jet are presented, with the jet issued near and below a free surface, parallel to it. The jet under study is isothermal and in fresh water, with air injectors that allow variation of the inlet air volume fraction between 0 and 13 %. Measurements of water velocity have been performed using LDV, and the jet exit conditions measured with PIV. Air volume fraction, bubble velocity and chord length distributions were measured with sapphire optical local phase detection probes. The mean free surface elevation and RMS fluctuations were obtained using local phase detection probes as well. Visualization was performed with laser-induced fluorescence. Measurements reveal that the mean free surface elevation and turbulent fluctuations significantly increase with the injection of air. The water normal Reynolds stresses are damped by the presence of bubbles in the bulk of the liquid, but very close to the free surface the effect is reversed and the normal Reynolds stresses increase slightly for the bubbly flow. The Reynolds shear stresses < {u^' } w^' } } rangle decrease when bubbles are injected, indicating turbulence attenuation, and are negative at deeper locations, as turbulent eddies shed downward carry high axial momentum deeper into the flow. Flow visualization reveals that the two-phase jet is lifted with the presence of bubbles and reaches the free surface sooner. Significant bubble coalescence is observed, leading to an increase in mean bubble size as the jet develops. The coalescence near the free surface is particularly strong, due to the time it takes the bubbles to pierce the free surface, resulting in a considerable increase in the local air volume fraction. In addition to first explore a bubbly surface jet, the comprehensive dataset reported herein can be used to validate two-phase flow models and computational tools.

  11. Theoretical investigation of flash vaporisation in a screw expander

    NASA Astrophysics Data System (ADS)

    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.

  12. Fluorescence Imaging Study of Transition in Underexpanded Free Jets

    NASA Technical Reports Server (NTRS)

    Wilkes, Jennifer A.; Danehy, Paul M.; Nowak, Robert J.

    2005-01-01

    Planar laser-induced fluorescence (PLIF) is demonstrated to be a valuable tool for studying the onset of transition to turbulence. For this study, we have used PLIF of nitric oxide (NO) to image underexpanded axisymmetric free jets issuing into a low-pressure chamber through a smooth converging nozzle with a sonic orifice. Flows were studied over a range of Reynolds numbers and nozzle-exit-to-ambient pressure ratios with the aim of empirically determining criteria governing the onset of turbulence. We have developed an image processing technique, involving calculation of the standard deviation of the intensity in PLIF images, in order to aid in the identification of turbulence. We have used the resulting images to identify laminar, transitional and turbulent flow regimes. Jet scaling parameters were used to define a rescaled Reynolds number that incorporates the influence of a varying pressure ratio. An empirical correlation was found between transition length and this rescaled Reynolds number for highly underexpanded jets.

  13. Numerical Study on GRB-Jet Formation in Collapsars

    SciTech Connect

    Nagataki, Shigehiro; Takahashi, Rohta; Mizuta, Akira; Takiwaki, Tomoya; /Tokyo U.

    2006-08-22

    Two-dimensional magnetohydrodynamic simulations are performed using the ZEUS-2D code to investigate the dynamics of a collapsar that generates a GRB jet, taking account of realistic equation of state, neutrino cooling and heating processes, magnetic fields, and gravitational force from the central black hole and self gravity. It is found that neutrino heating processes are not so efficient to launch a jet in this study. It is also found that a jet is launched mainly by B{sub {phi}} fields that are amplified by the winding-up effect. However, since the ratio of total energy relative to the rest mass energy in the jet is not so high as several hundred, we conclude that the jets seen in this study are not be a GRB jet. This result suggests that general relativistic effects, which are not included in this study, will be important to generate a GRB jet. Also, the accretion disk with magnetic fields may still play an important role to launch a GRB jet, although a simulation for much longer physical time {approx} 10-100 s is required to confirm this effect. It is shown that considerable amount of {sup 56}Ni is synthesized in the accretion disk. Thus there will be a possibility for the accretion disk to supply sufficient amount of {sup 56}Ni required to explain the luminosity of a hypernova. Also, it is shown that neutron-rich matter due to electron captures with high entropy per baryon is ejected along the polar axis. Moreover, it is found that the electron fraction becomes larger than 0.5 around the polar axis near the black hole by {nu}{sub e} capture at the region. Thus there will be a possibility that r-process and r/p-process nucleosynthesis occur at these regions. Finally, much neutrons will be ejected from the jet, which suggests that signals from the neutron decays may be observed as the delayed bump of the light curve of the afterglow or gamma-rays.

  14. Study on the characteristics of supersonic Coanda jet

    NASA Astrophysics Data System (ADS)

    Matsuo, Shigeru; Setoguchi, Toshiaki; Kudo, Takemasa; Yu, Shen

    1998-09-01

    Techniques using Coanda effect have been applied to the fluid control devices. In this field, experimental studies were so far performed for the spiral jet obtained by the Coanda jet issuing from a conical cylinder with an annular slit, thrust vectoring of supersonic Coanda jets and so on. It is important from the viewpoints of effective applications to investigate the characteristics of the supersonic Coanda jet in detail. In the present study, the effects of pressure ratios and nozzle configurations on the characteristics of the supersonic Coanda jet have been investigated experimentally by a schlieren optical method and pressure measurements. Furthermore, Navier-Stokes equations were solved numerically using a 2nd-order TVD finite-volume scheme with a 3rd-order three stage Runge-Kutta method for time integration. k - ɛ model was used in the computations. The effects of initial conditions on Coanda flow were investigated numerically. As a result, the simulated flow fields were compared with experimental data in good agreement qualitatively.

  15. Multi-wave studies of the jet in SS 433

    NASA Astrophysics Data System (ADS)

    Rushton, Anthony; Maccarone, Tom; Conway, John; Laing, Robert; Spencer, Ralph; Cawthorne, Tim

    2010-10-01

    Observations are proposed to study the core and extended jet of SS 433 in the cm and mm (and possibly near-IR bands). We request that near simultaneous multi-wavelength observations are coordinated with instruments with similar spacial resolutions: ATCA, EVLA, PdBI and VLT (with a coronagraph). Multi-epochs (three) will be used to study variation between the core and jet over a period of three weeks. A cross-band spectral index map at each epoch will then separate the expected power-law index of the jet, from the flat spectrum core, in order to test galactic jet models to unprecedented accuracy. In addition, the successful detection of variations in the extended jets at mm or near-IR bands will directly test changes in the outflow rate (as these bands are expected to be optically thin), whereas in the cm-bands this can be confused with changes in just the optical depth (e.g. the formation of a shock).

  16. Multi-wave studies of the jet in SS 433

    NASA Astrophysics Data System (ADS)

    Rushton, Anthony Peter; Maccarone, Tom; Conway, John; Laing, Robert; Black, John Harry; Spencer, Ralph; Cawthorne, Tim

    2011-04-01

    Observations are proposed to study the core and extended jet of SS 433 in the cm and mm (and possibly near-IR bands). We request that near simultaneous multi-wavelength observations are coordinated with instruments with similar spacial resolutions: ATCA, EVLA, e-MERLIN, ALMA and VLT (with a coronagraph). Multi-epochs (three) will be used to study variation between the core and jet over a period of three weeks. A cross-band spectral index map at each epoch will then separate the expected power-law index of the jet, from the flat spectrum core, in order to test galactic jet models to unprecedented accuracy. In addition, the successful detection of variations in the extended jets at mm or near-IR bands will directly test changes in the outflow rate (as these bands are expected to be optically thin), whereas in the cm-bands this can be confused with changes in just the optical depth (e.g. the formation of a shock).

  17. Vectoring of parallel synthetic jets: A parametric study

    NASA Astrophysics Data System (ADS)

    Berk, Tim; Gomit, Guillaume; Ganapathisubramani, Bharathram

    2016-11-01

    The vectoring of a pair of parallel synthetic jets can be described using five dimensionless parameters: the aspect ratio of the slots, the Strouhal number, the Reynolds number, the phase difference between the jets and the spacing between the slots. In the present study, the influence of the latter four on the vectoring behaviour of the jets is examined experimentally using particle image velocimetry. Time-averaged velocity maps are used to study the variations in vectoring behaviour for a parametric sweep of each of the four parameters independently. A topological map is constructed for the full four-dimensional parameter space. The vectoring behaviour is described both qualitatively and quantitatively. A vectoring mechanism is proposed, based on measured vortex positions. We acknowledge the financial support from the European Research Council (ERC Grant Agreement No. 277472).

  18. The Study on the Effects of Pimpinella anisum on Relief and Recurrence of Menopausal Hot Flashes.

    PubMed

    Nahidi, Fatemeh; Kariman, Nourossadat; Simbar, Masoumeh; Mojab, Faraz

    2012-01-01

    With respect to the high incidence of hot flash in postmenopausal women and the controversies regarding its treatment, this double-blind clinical trial was conducted to determine the effects of Pimpinella anisum on hot flashes in these women referring to rural and urban health centers of Qazvin Province in 2009. Seventy-two women with hot flashes were randomly selected according to the predetermined criteria and divided into two experimental and control groups. Their medical records at health centers were used for sampling. Each woman in the experimental group took a capsule containing 330 mg Pimpinella anisum 3 times a day while in the control group, women took 3 capsules, each containing 330 mg potato starch, over 4 weeks and after that, they were following up for 4 weeks. Before taking the capsules, they were assessed for 2 weeks about the frequency and severity of hot flashes. Data were collected through a questionnaire and an information form. Content validity method was used for validity of the tools. ANOVA and Student›s t-test were applied for statistical analysis. In the experimental group, the frequency and severity of hot flashes before the treatment were 4.21% and 56.21% and, after that, were 1.06% and 14.44% at the end of the fourth week respectively. No change was found in the frequency and severity of hot flashes in the control group. The frequency and severity of hot flashes was decreased during 4 weeks of follow up period. P. anisum is effective on the frequency and severity of hot flashes in postmenopausal women.

  19. The Study on the Effects of Pimpinella anisum on Relief and Recurrence of Menopausal Hot Flashes

    PubMed Central

    Nahidi, Fatemeh; Kariman, Nourossadat; Simbar, Masoumeh; Mojab, Faraz

    2012-01-01

    With respect to the high incidence of hot flash in postmenopausal women and the controversies regarding its treatment, this double-blind clinical trial was conducted to determine the effects of Pimpinella anisum on hot flashes in these women referring to rural and urban health centers of Qazvin Province in 2009. Seventy-two women with hot flashes were randomly selected according to the predetermined criteria and divided into two experimental and control groups. Their medical records at health centers were used for sampling. Each woman in the experimental group took a capsule containing 330 mg Pimpinella anisum 3 times a day while in the control group, women took 3 capsules, each containing 330 mg potato starch, over 4 weeks and after that, they were following up for 4 weeks. Before taking the capsules, they were assessed for 2 weeks about the frequency and severity of hot flashes. Data were collected through a questionnaire and an information form. Content validity method was used for validity of the tools. ANOVA and Student›s t-test were applied for statistical analysis. In the experimental group, the frequency and severity of hot flashes before the treatment were 4.21% and 56.21% and, after that, were 1.06% and 14.44% at the end of the fourth week respectively. No change was found in the frequency and severity of hot flashes in the control group. The frequency and severity of hot flashes was decreased during 4 weeks of follow up period. P. anisum is effective on the frequency and severity of hot flashes in postmenopausal women. PMID:24250540

  20. Experimental study on confined two-phase jets

    SciTech Connect

    Levy, Y.; Albagli, D. )

    1991-09-01

    The basic mixing phenomena in confined, coaxial, particle-laden turbulent flows are studied within the scope of ram combustor research activities. Cold-flow experiments in a relatively simple configuration of confined, coaxial two-phase jets provided both qualitative and quantitative insight on the multiphase mixing process. Pressure, tracer gas concentration, and two-phase velocity measurements revealed that unacceptably long ram combustors are needed for complete confined jet mixing. Comparison of the experimental results with a previous numerical simulation displayed a very good agreement, indicating the potential of the experimental facility for validation of computational parametric studies. 38 refs.

  1. Numerical Study on Cryogenic Coflowing Jets under Transcritical Conditions

    NASA Astrophysics Data System (ADS)

    Tani, Hiroumi; Teramoto, Susumu; Okamoto, Koji; Yamanishi, Nobuhiro

    2012-11-01

    A numerical and experimental study is presented on cryogenic coflowing jets under transcritical conditions for a better understanding of the propellant mixing in supercritical-pressure rocket engines. The major concerns are dominant flow structures in the mixing of cryogenic coflowing jets under transcritical conditions. Experimentally, in advance of detailed numerical simulations, cryogenic nitrogen/gaseous nitrogen coaxial jets were visualized by the backlighting photography technique. It was observed that a dense nitrogen core has a shear-layer instability near the injector exit and eventually breaks up into large lumps which dissolve and fade away downstream. In numerical simulations, LES technique was employed for more detailed discussion on the flow structures. LES of a cryogenic nitrogen/gaseous nitrogen coflowing plane jet was conducted with the same density and velocity ratios of inner/outer jets as the experiments. As observed in the experiments, the shear-layer instability in the inner mixing layers is predominant near the injector exit. After roll-up and paring, the shear-layer instability waves become large-scale vortices. They cause coherent vortex structures which become dominant in the downstream and break the dense core into lumps. Strouhal numbers of the shear-layer instability and the dense lump shedding in the numerical simulations were comparable to those measured in the experiments, respectively.

  2. A study of jet mass distributions with grooming

    NASA Astrophysics Data System (ADS)

    Marzani, Simone; Schunk, Lais; Soyez, Gregory

    2017-07-01

    We perform a phenomenological study of the invariant mass distribution of hadronic jets produced in proton-proton collisions, in conjunction with a grooming algorithm. In particular, we consider the modified MassDrop Tagger (mMDT), which corresponds to Soft Drop with angular exponent β = 0. Our calculation, which is differential in both jet mass and jet transverse momentum, resums large logarithms of the jet mass, including the full dependence on the groomer's energy threshold z cut, and it is matched to fixed-order QCD matrix elements at next-to-leading order. In order to account for non-perturbative contributions, originating from the hadronisation process and from the underlying event, we also include a phenomenological correction factor derived from Monte Carlo parton shower simulations. Furthermore, we consider two different possibilities for the jet transverse momentum: before or after grooming. We show that the former should be preferred for comparisons with upcoming experimental data essentially because the mMDT transverse momentum spectrum is not collinear safe, though the latter exhibits less sensitivity to underlying event and displays properties that may provide complementary information for probing non-perturbative effects.

  3. An experimental study of planar heterogeneous supersonic confined jets

    NASA Astrophysics Data System (ADS)

    Tanis, Frederick J., Jr.

    1994-12-01

    The effects of varying the exit pressure of a supersonic helium jet exhausting coaxially with two parallel supersonic air streams into a constant area duct were investigated. The method used to evaluate the mass entrainment rate was to measure helium molar concentration profiles and mass flux across the duct using a binary gas probe then calculate the mass entrainment into the helium jet. In order to conduct this study a novel binary gas probe was developed which allowed helium concentration and mass flux data to be obtained during continuous traverses across the supersonic flowfield. High exit pressure ratio (EPR) led to improved overall mixing compared to the baseline case with an EPR near unity. The high EPR caused low mass entrainment along the jet shear layers due to high convective Mach numbers and velocity ratios, but the high EPR caused oblique shocks to form which reflected off the duct walls and intersected with the helium jet several times causing significant mass entrainment due to numerous shock-shear layer interactions (SSLI's). A correlation between the vorticity generated during a SSLI and the mass entrainment into the jet was developed.

  4. Acupuncture for the treatment of hot flashes in patients with breast cancer receiving antiestrogen therapy: a pilot study in Korean women.

    PubMed

    Jeong, Young Ju; Park, Young Sun; Kwon, Hyo Jung; Shin, Im Hee; Bong, Jin Gu; Park, Sung Hwan

    2013-08-01

    Antiestrogen therapy can cause vasomotor symptoms similar to those occurring during menopause, including hot flashes. Recent studies suggest that acupuncture is effective in reducing vasomotor symptoms in patients with breast cancer receiving tamoxifen. The purpose of this study was to assess the feasibility and safety of acupuncture for treatment of hot flashes in Korean patients with breast cancer receiving antiestrogen therapy. This was a prospective single-arm observational study using before and after measurements. The study was located at the East-West Medical Center at Daegu Catholic University Medical Center, Daegu, Korea. The subjects were 10 patients with breast cancer who were undergoing antiestrogen therapy with tamoxifen or anastrozole and who were suffering from hot flashes. Acupuncture was administered 3 times a week for 4 consecutive weeks, for 20±5 minutes at each session. The outcome measure was severity of hot flashes assessed by visual analogue scale (VAS) and total hot flash score. During treatment, severity of hot flashes was reduced by 70%-95% in all patients. Acupuncture significantly alleviated severity of hot flashes assessed by a visual analogue scale (F=30.261; p<0.001) as well as the total hot flash score (F=21.698; p=0.006). Four (4) weeks after the final treatment, symptoms were not aggravated. Acupuncture appeared to provide effective relief from hot flashes among Korean women receiving antiestrogen therapy after surgery for breast cancer, and the effects lasted for at least 1 month after termination of treatment. A randomized controlled prospective study with a larger sample size is required to clarify the role of acupuncture in the management of hot flashes in Korean patients with breast cancer.

  5. Acupuncture for the Treatment of Hot Flashes in Patients with Breast Cancer Receiving Antiestrogen Therapy: A Pilot Study in Korean Women

    PubMed Central

    Jeong, Young Ju; Park, Young Sun; Kwon, Hyo Jung; Shin, Im Hee; Bong, Jin Gu

    2013-01-01

    Abstract Objectives Antiestrogen therapy can cause vasomotor symptoms similar to those occurring during menopause, including hot flashes. Recent studies suggest that acupuncture is effective in reducing vasomotor symptoms in patients with breast cancer receiving tamoxifen. The purpose of this study was to assess the feasibility and safety of acupuncture for treatment of hot flashes in Korean patients with breast cancer receiving antiestrogen therapy. Design This was a prospective single-arm observational study using before and after measurements. Settings/location The study was located at the East–West Medical Center at Daegu Catholic University Medical Center, Daegu, Korea. Subjects The subjects were 10 patients with breast cancer who were undergoing antiestrogen therapy with tamoxifen or anastrozole and who were suffering from hot flashes. Interventions Acupuncture was administered 3 times a week for 4 consecutive weeks, for 20±5 minutes at each session. Outcome measures The outcome measure was severity of hot flashes assessed by visual analogue scale (VAS) and total hot flash score. Results During treatment, severity of hot flashes was reduced by 70%–95% in all patients. Acupuncture significantly alleviated severity of hot flashes assessed by a visual analogue scale (F=30.261; p<0.001) as well as the total hot flash score (F=21.698; p=0.006). Four (4) weeks after the final treatment, symptoms were not aggravated. Conclusions Acupuncture appeared to provide effective relief from hot flashes among Korean women receiving antiestrogen therapy after surgery for breast cancer, and the effects lasted for at least 1 month after termination of treatment. A randomized controlled prospective study with a larger sample size is required to clarify the role of acupuncture in the management of hot flashes in Korean patients with breast cancer. PMID:23383974

  6. Flash Floods Simulation Using a Physical based hydrological Model at the Eastern Nile Basin: Case studies; Wadi Assiut, Egypt and Wadi Gumara, Lake Tana, Ethiopia.

    NASA Astrophysics Data System (ADS)

    Saber, M.; Sefelnasr, A.; Yilmaz, K. K.

    2015-12-01

    Flash flood is a natural hydrological phenomenon which affects many regions of the world. The behavior and effect of this phenomenon is different from one region to the other regions depending on several issues such as climatology and hydrological and topographical conditions at the target regions. Wadi assiut, Egypt as arid environment, and Gumara catchment, Lake Tana, Ethiopia, as humid conditions have been selected for application. The main target of this work is to simulate flash floods at both catchments considering the difference between them on the flash flood behaviors based on the variability of both of them. In order to simulate the flash floods, remote sensing data and a physical-based distributed hydrological model, Hydro-BEAM-WaS (Hydrological River Basin Environmental Assessment Model incorporating Wadi System) have been integrated used in this work. Based on the simulation results of flash floods in these regions, it was found that the time to reach the maximum peak is very short and consequently the warning time is very short as well. It was found that the flash floods starts from zero flow in arid environment, but on the contrary in humid arid, it starts from Base flow which is changeable based on the simulated events. Distribution maps of flash floods showing the vulnerable regions of these selected areas have been developed. Consequently, some mitigation strategies relying on this study have been introduced. The proposed methodology can be applied effectively for flash flood forecasting at different climate regions, however the paucity of observational data.

  7. Numerical study of nanoparticle formation in a free turbulent jet

    NASA Astrophysics Data System (ADS)

    Gilfanov, A. K.; Koch, W.; Zaripov, S. K.; Rybdylova, O. D.

    2016-11-01

    Di-ethyl-hexyl-sebacate (DEHS) aerosol nanoparticle formation in a free turbulent jet as a result of nucleation, condensation and coagulation is studied using fluid flow simulation and the method of moments under the assumption of lognormal particle size distribution. The case of high nucleation rates and the coagulation-controlled growth of particles is considered. The formed aerosol performance is jet is numerically investigated for the various nozzle diameters and two approximations of the saturation pressure dependence on the temperature. It is demonstrated that a higher polydispersity of the aerosol is obtained for smaller nozzle diameters.

  8. Does pressure antagonize anesthesia? High-pressure stopped-flow study of firefly luciferase and anatomy of initial flash.

    PubMed Central

    Ueda, I; Minami, H; Matsuki, H; Inoue, T

    1999-01-01

    The antagonizing effect of high pressure against anesthesia is well known. With purified firefly luciferase, however,. Biophys. J. 60:1309-1314) reported that high pressure did not affect the initial flash intensity. Firefly luciferase emits a burst of light when the substrates luciferin and ATP are added in the presence of O2. The light intensity decays rapidly and the weak light lasts for hours. The initial flash is a transient event and is not in a steady state. The steady state is represented by the slope of the linear part of the integral of the light output. The present study used a high-pressure stopped-flow system to compare the pressure effects on the initial flash intensity and the steady-state light intensity. The flash intensity did not change by the application of hydrostatic pressure in the presence or absence of chloroform or 1-octanol. In contrast, high pressure increased the steady-state light intensity. The application of 12 MPa pressure increased the steady-state light intensity of firefly luciferase inhibited by 5 mM chloroform or 0.7 mM 1-octanol by 19.7% and 18.8%, respectively. When analyzed by the rapid reaction kinetics of the transition state theory, the initial peak intensity represents the total amount of active enzyme and is unrelated to the reaction rate. Anesthetics inhibited the initial flash by unfolding the protein, thereby decreasing the concentration of the active enzyme. Pressure affected the steady-state light intensity by changing the reaction rates. PMID:9876160

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  10. On the use of continuous flash suppression for the study of visual processing outside of awareness

    PubMed Central

    Yang, Eunice; Brascamp, Jan; Kang, Min-Suk; Blake, Randolph

    2014-01-01

    The interocular suppression technique termed continuous flash suppression (CFS) has become an immensely popular tool for investigating visual processing outside of awareness. The emerging picture from studies using CFS is that extensive processing of a visual stimulus, including its semantic and affective content, occurs despite suppression from awareness of that stimulus by CFS. However, the current implementation of CFS in many studies examining processing outside of awareness has several drawbacks that may be improved upon for future studies using CFS. In this paper, we address some of those shortcomings, particularly ones that affect the assessment of unawareness during CFS, and ones to do with the use of “visible” conditions that are often included as a comparison to a CFS condition. We also discuss potential biases in stimulus processing as a result of spatial attention and feature-selective suppression. We suggest practical guidelines that minimize the effects of those limitations in using CFS to study visual processing outside of awareness. PMID:25071685

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

    NASA Astrophysics Data System (ADS)

    Wine, Paul H.; Nicovich, J. M.; Hynes, Anthony J.; Stickel, Robert E.; Thorn, R. P.; Chin, Mian; Cronkhite, Jeffrey A.; Shackelford, Christie J.; Zhao, Zhizhong; Daykin, Edward P.; van Dijk, Cornelius A.; Wang, Shouzhi; Steidl, Jill V.

    1993-02-01

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

  12. Study of Underexpanded Sonic Jets by Numerical Simulation

    NASA Astrophysics Data System (ADS)

    Thanigaiarasu, S.; Karthick, R.; Arunprasad, R.; SyedMusthafa, H.; Elangovan, S.; Rathakrishnan, E.

    2013-03-01

    This paper deals with the numerical simulation of sonic underexpanded axi-symmetric jets, issuing from a convergent nozzle, at different nozzle pressure ratios. The simulations have been carried out by solving the unsteady Reynolds Average Navier-Stokes (RANS) equations utilizing the realizable k-ɛ (epsilon) two equations turbulence model in the commercial software FLUENT (version 6.3.26). The flow is assumed to be axi-symmetric and turbulent. The computational domain included a convergent nozzle of length 50 mm and a rectangular domain of size 25 times the nozzle exit diameter (D) verses 4D, which have been modeled and meshed in GAMBIT (version 2.46). The grid consisted of 81020 cells, while gradient grid adaptions were performed later to pronounce the accuracy of the results and visualize the shock-cell structures. From the simulations, it is inferred that, for correctly expanded jets, the potential core extends upto 6D, where D is the exit diameter of the nozzle. For underexpanded jets, the shock-cell structures in the jet flow field were captured properly. A pattern of `shock-diamonds' or shock-cells were observed in the flow at low NPR. The formation of shock-cell is found to change considerably and also its strength increases with increase in nozzle pressure ratio (NPR). From this study, it is clear that the effect of favorable pressure gradient in the underexpanded jet influences the jet characteristics significantly. At high NPRs, `Mach disc' formation is observed in the flow field. The flow after the Mach disc becomes subsonic and regains energy from the surrounding fluid.

  13. Experimental and numerical study of pulsating transversal jets

    NASA Astrophysics Data System (ADS)

    Goldfeld, M. A.; Fedorova, N. N.; Fedorchenko, I. A.; Pozdnyakov, G. A.; Timofeev, K. Yu.; Zhakharova, Yu. V.

    2015-06-01

    Paper presents results of joint experimental and numerical investigation of pulsating jet penetration into still air and supersonic flow. Goal of the study is to investigate two-dimensional (2D) Hartmann generator (HG) properties and clear up its possibilities in providing better mixing between air and secondary (injected) gases.

  14. Flow and atomization in flashing injectors

    NASA Technical Reports Server (NTRS)

    Solomon, A. S. P.; Rupprecht, S. D.; Chen, L.-D.; Faeth, G. M.

    1985-01-01

    Flashing injection involves expanding a fluid through an injector until a supersaturated state is reached, causing a portion of the fluid to flash to a vapor. This investigation considered the flow, atomization and spreading properties of flashing injectors with flowing liquids containing dissolved gases (Jet A/air) as well as superheated liquids (Freon-11). The use of a two-stage expansion process, separated by an expansion chamber, was found to be beneficial for good atomization properties of flashing injection - particularly for dissolved gas systems. Both locally homogeneous and separated flow models provided good predictions of injector flow properties. Conventional correlations for drop sizes from pressure and airblast injectors were successfully modified, using the separated flow model to prescribe injector exit conditions, and to correlate drop size measurements. Additional experimental results are provided for spray angles of sprays from flashing injectors.

  15. Atomization and combustion properties of flashing injectors

    NASA Technical Reports Server (NTRS)

    Solomon, A. S. P.; Rupprecht, S. D.; Chen, L.-D.; Faeth, G. M.

    1982-01-01

    Flashing injection involves expanding a fluid through an injector until a supersaturated state is reached, causing a portion of the fluid to flash to a vapor. This investigation considered the flow, atomization and spreading properties of flashing injectors flowing liquids containing dissolved gases (Jet A/air) as well as superheated liquids (Freon 11). The use of a two stage expansion process, separated by an expansion chamber, was found to be beneficial for good atomization properties of flashing injection - particularly for dissolved gas systems. Both locally homogeneous and separated flow models provided good predictions of injector flow properties. Conventional correlations for drop sizes from pressure atomized and airblast injectors were successfully modified, using the separated flow model to prescribe injector exit conditions, to correlate drop size measurements. Additional experimental results are provided for spray angle and combustion properties of sprays from flashing injectors.

  16. Sediment transport during flash flood events on an intermittent river: an experimental laboratory study.

    NASA Astrophysics Data System (ADS)

    Moustabachir, H.; Chahinian, N.; Romieux, N.; Vittenet, J.; Gayrard, E.; Tournoud, M. G.

    2009-04-01

    Flash floods have a number of impacts on the water quality of river systems because the later is the resultant of pollutant input into the river and its transformation along its course. In the case of intermittent rivers this impact is increased by the long drought periods that usually precede such floods. Indeed, the pollutants are known to accumulate in the dry river sediments during the drought period and are flushed away by the first floods. The Vène, a small experimental catchment (67 km²) located in southern France is a perfect example of this type of behavior. The field data collected on the catchment since 1994 through routine and flood monitoring clearly show an increase in suspended solids and nutrient concentrations during flash floods. However, the hydraulic conditions which lead to the triggering of sediment movement and re-suspension are not known. The aim of this study is to investigate sediment re-suspension mechanisms by reproducing the dynamics of sediment movement during flash floods at the reach scale in controlled laboratory conditions. A rectangular flume (6m*0.29m*0.18m) is used as a scale model of a 1 km reach. Variable flow conditions can be set in the flume through a quarter turn valve. Discharge values are monitored using an electromagnetic flow meter and water velocity measurements are carried out in the flume using a Pitot probe coupled to a digital manometer. Dynamic similarity is imposed between the reach and the flume i.e. the reach's Froude number is set equal to that of the flume. The reach's rating curve is used to determine a set of experimental height and flow values for the flume. For each test, the slope of the flume is modified in order to respect the rating curve. The flume's bed is reconstructed by respecting the similarity ratios determined previously using glass micro beads to represent its sediments. Various tests are carried out in steady-state conditions for different discharge values. In transient conditions, the

  17. The Relation between Hot Flashes and Ambulatory Blood Pressure: The Hilo Women’s Health Study

    PubMed Central

    Brown, Daniel E.; Sievert, Lynnette L.; Morrison, Lynn A.; Rahberg, Nichole; Reza, Angela

    2011-01-01

    Objectives Hot flashes (HFs) have been associated with elevated blood pressure, but studies have not examined the relationship between objectively measured HFs and blood pressure during normal daily activities. The objectives of this study are to examine ambulatory blood pressure (BP) differences between women who report HFs and those who do not, and to observe whether an objectively measured HF is associated with transient changes in BP. Methods A sample of 202 women in Hilo, Hawaii aged 45–55 years were asked to fill out a questionnaire that included demographic information and an inventory of symptoms. The women underwent simultaneous 24-hour monitoring of ambulatory BP and HFs, while keeping a diary that included mood and HF reports. Results No significant difference was present in mean BP between women who reported having a HF during the past 2 weeks and those who did not. When measurements controlled for negative mood reports and posture, there was a highly significant elevation in Z scores of systolic BP when a measured, objective HF occurred within 10 minutes preceding a BP reading, and a significant elevation of Z scores of diastolic BP when a subjectively reported HF occurred within 10 minutes after a BP reading. Conclusions These results suggest that objectively measured HFs precede transient elevations of systolic BP, but it is unclear if there is a causal relationship. These results also suggest that women experience subjective HFs within 10 minutes after a transient increase in diastolic BP. Again, the causal relationship is not understood. PMID:21183716

  18. Geomorphological factors of flash floods

    NASA Astrophysics Data System (ADS)

    Kuznetsova, Yulia

    2016-04-01

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

  19. Gabapentin for the management of hot flashes in prostate cancer survivors: a longitudinal continuation Study-NCCTG Trial N00CB.

    PubMed

    Moraska, Amanda R; Atherton, Pamela J; Szydlo, Daniel W; Barton, Debra L; Stella, Philip J; Rowland, Kendrith M; Schaefer, Paul L; Krook, James; Bearden, James D; Loprinzi, Charles L

    2010-01-01

    Hot flashes are a complication of androgen deprivation therapy for prostate cancer. A phase III study showed that use of low-dose gabapentin was well tolerated and moderately decreased the frequency of hot flashes due to androgen deprivation therapy when taken for 4 weeks. The current study, an open-label continuation of the randomized study, examined the efficacy and toxicity of gabapentin when taken for (an additional) 8 weeks. Patients were allowed to start, or continue, gabapentin and to titrate the dose to maximum efficacy, up to 900 mg/d. They were asked to complete a hot flash diary daily and keep weekly logs of toxicity, satisfaction with hot flash control, and quality of life. The moderate reduction in hot flash frequency and severity in the randomized phase of the study appeared to be maintained during this continuation phase. Men originally receiving the placebo or lowest dose of gabapentin (300 mg/d) had improved hot flash control relative to that at the end of the randomized phase. Minimal adverse effects were reported. These findings suggest that low-dose gabapentin is moderately efficacious for at least 12 weeks of hot flash treatment in men undergoing androgen deprivation therapy for prostate cancer and seems to be well tolerated. (NCT00028572)

  20. Laser flash photolysis study of electron transfer reactions of phenolate ions with aromatic carbonyl triplets

    SciTech Connect

    Das, P.K.; Bhattacharyya, S.N.

    1981-01-01

    Light-induced electron transfer reactions from phenolate ions to a variety of carbonyl triplets have been studied in aqueous acetonitrile by using 337.1-nm laser flash photolysis. In particular, the effects of carbonyl triplet nature and substitution in phenolate ions have been examined with respect to both kinetics and primary photoproduct yields. The rate constants for electron transfer are found to be in the range 2 x 10/sup 9/-1 x 10/sup 10/ M/sup -1/ s/sup -1/. The quantum yields of primary photoproducts (phenoxy radicals and radical anions of carbonyl compounds) are essentially unity except with p-bromo- and p-iodophenolate ions. With p-iodophenolate ion, the yields of ketone-derived radical ions are in the range 0.3 to 0.5 and remain practially unchanged on increasing the temperature from 23 to 75/sup 0/C. This result suggests the involvement of heavy atom induced intersystem crossing and/or back electron transfer at some stage(s) of the electron transfer reaction mechanism. 6 figures, 4 tables.

  1. Comparative Study of Bunch Length And Arrival Time Measurements at FLASH

    SciTech Connect

    Schlarb, H.; Azima, A.; Dusterer, S.; Huning, M.; Knabbe, E.A.; Roehrs, M.; Rybnikov, V.; Schmidt, B.; Steffen, B.; Ross, M.C.; Schmueser, P.; Winter, A.; /Hamburg U.

    2007-04-16

    Diagnostic devices to precisely measure the longitudinal electron beam profile and the bunch arrival time require elaborate new instrumentation techniques. At FLASH, two entirely different methods are used. The bunch profile can be determined with high precision by a transverse deflecting RF structure, but the method is disruptive and does not allow to monitor multiple bunches in a macro-pulse train. It is therefore complemented by two non-disruptive electrooptical devices, called EO and TEO. The EO setup uses a dedicated diagnostic laser synchronized to the machine RF. The longitudinal electron beam profile is encoded in the intensity profile of a chirped laser pulse and analyzed by looking at the spectral composition of the pulse. The second setup, TEO, utilizes the TiSa-based laser system used for pump-probe experiments. Here, the temporal electron shape is encoded into the spatial dimension of the laser pulse by an intersection angle between the laser and the electron beam at the EO-crystal. In this paper, we present a comparative study of bunch length and arrival time measurements performed simultaneously with all three experimental techniques.

  2. MAXI and GLAST Studies of Jets in Active Galaxies

    SciTech Connect

    Madejski, Greg; Kataoka, Jun; Sikora, Marek

    2008-10-13

    The recent launch of GLAST--coinciding with the MAXI workshop--opens a new era for studies of jet-dominated active galaxies, known as blazars. While the emission processes operating in various spectral bands in blazars are reasonably well understood, the knowledge of the details of the structure of the jet, location of the dissipation region with respect to the accreting black hole, and coupling of the jet to the accretion process are known only at a rudimentary level. Blazars are variable, and this provides an opportunity to use the variability in various bands--and in particular, the relationship of respective time series to each other--to explore the relative location of regions responsible for emission in the respective bands. Observationally, this requires well-sampled time series in as many spectral bands as possible. To this end, with its all-sky, sensitive monitoring capability, the recently launched GLAST, and MAXI, to be deployed in 2009, are the most promising instruments bound to provide good sampling in respectively the energetic gamma-ray, and the soft X-ray band. This paper highlights the inferences regarding blazar jets that can be gleaned from such joint observations.

  3. Symmetric Coronal Jets: A Reconnection-controlled Study

    NASA Astrophysics Data System (ADS)

    Rachmeler, L. A.; Pariat, E.; DeForest, C. E.; Antiochos, S.; Török, T.

    2010-06-01

    Current models and observations imply that reconnection is a key mechanism for destabilization and initiation of coronal jets. We evolve a system described by the theoretical symmetric jet formation model using two different numerical codes with the goal of studying the role of reconnection in this system. One of the codes is the Eulerian adaptive mesh code ARMS, which simulates magnetic reconnection through numerical diffusion. The quasi-Lagrangian FLUX code, on the other hand, is ideal and able to evolve the system without reconnection. The ideal nature of FLUX allows us to provide a control case of evolution without reconnection. We find that during the initial symmetric and ideal phase of evolution, both codes produce very similar morphologies and energy growth. The symmetry is then broken by a kink-like motion of the axis of rotation, after which the two systems diverge. In ARMS, current sheets formed and reconnection rapidly released the stored magnetic energy. In FLUX, the closed field remained approximately constant in height while expanding in width and did not release any magnetic energy. We find that the symmetry threshold is an ideal property of the system, but the lack of energy release implies that the observed kink is not an instability. Because of the confined nature of the FLUX system, we conclude that reconnection is indeed necessary for jet formation in symmetric jet models in a uniform coronal background field.

  4. Experimental and Computational Study of Sonic and Supersonic Jet Plumes

    NASA Technical Reports Server (NTRS)

    Venkatapathy, E.; Naughton, J. W.; Fletcher, D. G.; Edwards, Thomas A. (Technical Monitor)

    1994-01-01

    Study of sonic and supersonic jet plumes are relevant to understanding such phenomenon as jet-noise, plume signatures, and rocket base-heating and radiation. Jet plumes are simple to simulate and yet, have complex flow structures such as Mach disks, triple points, shear-layers, barrel shocks, shock-shear-layer interaction, etc. Experimental and computational simulation of sonic and supersonic jet plumes have been performed for under- and over-expanded, axisymmetric plume conditions. The computational simulation compare very well with the experimental observations of schlieren pictures. Experimental data such as temperature measurements with hot-wire probes are yet to be measured and will be compared with computed values. Extensive analysis of the computational simulations presents a clear picture of how the complex flow structure develops and the conditions under which self-similar flow structures evolve. From the computations, the plume structure can be further classified into many sub-groups. In the proposed paper, detail results from the experimental and computational simulations for single, axisymmetric, under- and over-expanded, sonic and supersonic plumes will be compared and the fluid dynamic aspects of flow structures will be discussed.

  5. Experimental study of the development and structure of high-velocity liquid jets in air

    NASA Astrophysics Data System (ADS)

    Baev, V. K.; Bazhaikin, A. N.; Buzukov, A. A.; Timoshenko, B. P.; Bichenko, E. I.

    The dynamics of unsteady high-velocity liquid jets injected into air were studied by methods of high-speed cinematography, roentgenography, microphotography using pulsed lasers, and pulsed X-rays. It has been shown that in a jet with a positive longitudinal velocity gradient, a hydrodynamical instability develops, resulting in the appearance of density inhomogeneity. The concentration of liquid components along the jet differs by an order of magnitude. The compression and rarefaction waves affecting the jet structure and the flow pattern at its different sections may propagate along the jet. A cumulative type flow develops at the head of the high-velocity jet in a gaseous medium.

  6. Distance of myofilament sliding per ATP molecule in skeletal muscle fibers studied using laser flash photolysis of caged ATP.

    PubMed

    Yamada, T; Abe, O; Kobayashi, T; Sugi, H

    1993-01-01

    We studied the distance of myofilament sliding per hydrolysis of one ATP molecule by recording shortening of single glycerinated muscle fibers induced by laser flash photolysis of caged ATP, diffusion of photochemically released ATP out of the fiber being prevented by surrounding the fiber with silicone oil. With 75 microM ATP released (one half of the total myosin head concentration within the fiber), the fiber showed the minimum shortening (10 +/- 2 nm/half sarcomere, n = 10) taking place uniformly in each sarcomere in the fiber. Comparison of the initial flash-induced shortening velocity with the force-velocity relation of maximally Ca(2+)-activated fibers indicated that the above minimum fiber shortening took place under an internal load nearly equal to Po. These results may be taken to indicate that, under a nearly isometric condition, the distance of myofilament sliding per hydrolysis of one ATP molecule is of the order of 10 nm.

  7. Coupling Flash LC with MS for enrichment and isolation of milk oligosaccharides for functional studies

    PubMed Central

    Strum, John S.; Aldredge, Danielle; Barile, Daniela; Lebrilla, Carlito B.

    2013-01-01

    Mass spectrometry has been coupled with flash liquid chromatography to yield new capabilities for isolating non-chromophoric material from complicated biological mixtures. A flash LC/MS/MS method enabled fraction collection of milk oligosaccharides from biological mixtures based on composition and structure. The method is compatible with traditional gas-pressure driven flow flash chromatography, widely employed in organic chemistry laboratories. The on-line mass detector enabled real-time optimization of chromatographic parameters to favor separation of oligosaccharides that would otherwise be indistinguishable from co-eluting components with a non-specific detector. Unlike previously described preparative LC/MS techniques, we have employed a dynamic flow connection that permits any flow rate from the flash system to be delivered from 1–200 mL/min without affecting the ionization conditions of the mass spectrometer. A new way of packing large amounts of graphitized carbon allowed the enrichment and separation of milligram quantities of structurally heterogeneous mixtures of human milk oligosaccharides (HMOs) and bovine milk oligosaccharides (BMOs). Abundant saccharide components in milk, such as lactose and lacto-N-tetraose, were separated from the rarer and less abundant oligosaccharides that have greater structural diversity and biological functionality. Neutral and acidic HMOs and BMOs were largely separated and enriched with a dual binary solvent system. PMID:22370281

  8. Flash-Fire Propensity and Heat-Release Rate Studies of Improved Fire Resistant Materials

    NASA Technical Reports Server (NTRS)

    Fewell, L. L.

    1978-01-01

    Twenty-six improved fire resistant materials were tested for flash-fire propensity and heat release rate properties. The tests were conducted to obtain a descriptive index based on the production of ignitable gases during the thermal degradation process and on the response of the materials under a specific heat load.

  9. Randomized, double-blind, placebo-controlled, crossover study of sertraline (Zoloft) for the treatment of hot flashes in women with early stage breast cancer taking tamoxifen.

    PubMed

    Kimmick, Gretchen G; Lovato, James; McQuellon, Richard; Robinson, Emily; Muss, Hyman B

    2006-01-01

    We observed the relief of hot flashes in breast cancer survivors taking tamoxifen and treated with sertraline for depression. Our objective was to assess the effect of sertraline on the frequency and severity of hot flashes, mood status, and health-related quality of life. We used a randomized, double-blind, placebo-controlled, crossover study using 6 weeks of sertraline (50 mg each morning) versus placebo. Study participants were 62 breast cancer survivors from an oncology clinic in a tertiary care center on adjuvant tamoxifen reporting bothersome hot flashes. Patients were asked to keep a daily hot flash diary to record hot flash frequency and severity, from which hot flash scores (frequency x severity) were calculated. The Center for Epidemiologic Studies depression scale and Functional Assessment of Cancer Therapy--Breast (FACT-B) (at baseline, 6 weeks, and 12 weeks) were used to assess mood and quality of life. Sixty-two women were accrued. Forty-seven women (median age 53.9 years, range 36.6-77.1 years; 89% postmenopausal; 85.5% Caucasian) completed the first 6 weeks and 39 completed 12 weeks. The baseline daily hot flash frequency and score were 5.8 (standard deviation 4.1) and 11.5 (14.0), respectively. At the end of the first 6 weeks, hot flash frequency decreased by 50% in 36% of those taking sertraline compared to 27% taking placebo. In the crossover analysis, sertraline was significantly more effective than placebo: women crossing from placebo to sertraline had a decrease (-0.9 and -1.7) in hot flash frequency and score, whereas those crossing from sertraline to placebo had an increase (1.5 and 3.4) in hot flash frequency and score (p = 0.03 and 0.03). Forty-eight percent preferred the sertraline period, 11% preferred the placebo period, and 41% had no preference (p = 0.006). Measures of depression and quality of life were within normal range and did not change significantly within treatment groups. Sertraline decreases hot flashes in breast cancer

  10. A study on the phenomena of flash-sintering with tetragonal zirconia

    NASA Astrophysics Data System (ADS)

    Francis, John Stanley Curtis

    A new method for the sintering of ceramics will be presented in detail. This method called Flash-Sintering was first reported in 2010 by Cologna et al. In Flash-Sintering an electric field is applied across a "green" sample with a pair of electrodes and the sintering is measured as a function of the field and temperature. The electric field is shown to remarkably enhance densification. Both the sintering time to achieve near full density and the temperature required are reduced substantially. These changes allow for sintering of 3m% yttria stabilized zirconia at furnace temperatures below 850°C in a matter of seconds. The objective of this dissertation is to understand the phenomenological behavior of flash-sintering. This new method is a highly non-linear event which occurs at a particular temperature for a given applied field and sintering is accompanied by an abrupt rise in the conductivity. The development of relationships between the electrical control parameters, the sintering behavior, and the evolution of the microstructure are the principal themes of this doctoral research. The present work covers the following topics: (i) The influence of uniaxial pressure applied in combination with electrical field on sintering and superplastic deformation, which show an equivalence between mechanical and electrical driving forces, (ii) A shift of the flash to a higher temperature with increasing particle size of the ceramic powders, (iii) The influence of the electric field on the incubation time for the onset of the flash in experiments carried out at isothermal furnace temperatures, and the effect of the current density immediately following the flash on densification, (iv) The relationship between electrical parameters on microstructure (grain size) evolution, (v) A comparison with the microstructure and mechanical strength of specimens prepared by conventional sintering, and (vi) Measurement of luminescence spectra, which lies in the visible range, that

  11. [Electrical flash burns, about 33 cases. A 10-year retrospective study. Epidemiology, treatment and prevention].

    PubMed

    Carloni, R; Pechevy, L; Quignon, R; Yassine, A-H; Forme, N; Zakine, G

    2015-04-01

    The electric flash burns are a common cause of accident at workplace, especially among electricians. The aim of this study is to determine the parts of the body most often burned by the flash, to define the usual course and finally to give some simple rules of care and prevention. This is a retrospective, observational and descriptive study including all patients treated at the University Hospital of Tours for electrical flash burns between 1 January 2003 and 01 January 2013. A collection of medical and socio-economic data was achieved. We present 3 cases of patients hospitalized in our department. Thirty-three patients were included. In our series, all hospitalized patients were men. The average age was 43.2years (range 18 to 82years). In 81% of cases, the burn was due to a low voltage source, in 19% of cases to a high voltage source. It was an accident at workplace for 71% of patients, of whom 67% were electricians. The average total burned area was 9,52% (from 1.5% to 24%). The main locations included the face (86%), upper limbs (86%) and hands (86%). Medical treatment has healed 95% of patients. A surgical procedure was required in 5% of cases. A post-traumatic stress was found in 41% of patients. Outpatient treatment was performed in 36% of cases. Flash burns remain a common cause of hospitalization. Screening for hearing and eye disorders, a post-traumatic stress, as well as the prescription of early physiotherapy for burned hands are important components of their management. Following simple rules of prevention would limit their morbidity. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  12. A study of changes in apparent ionospheric reflection height within individual lightning flashes

    NASA Astrophysics Data System (ADS)

    Somu, Vijaya B.; Rakov, Vladimir A.; Haddad, Michael A.; Cummer, Steven A.

    2015-12-01

    Ionospheric reflection heights estimated using the zero-to-zero and peak-to-peak methods to measure skywave delay relative to the ground wave were compared for 108 first and 124 subsequent strokes at distances greater than 100 km. For either metric there was a considerable decrease in average reflection height for subsequent strokes relative to first strokes. We showed that the observed difference cannot be explained by the difference in frequency content of first and subsequent return-stroke currents. Apparent changes in reflection height (estimated using the peak-to-peak method) within individual flashes for 54 daytime and 11 nighttime events at distances ranging from 50 km to 330 km were compared, and significant differences were found. For daytime conditions, the majority of the flashes showed either decrease (57%) or non-monotonic variation (39%) in reflection height with respect to the immediately preceding stroke. With respect to the first stroke, 91% of the flashes showed monotonic decrease in height. For nighttime flashes, patterns in reflection height changes with respect to the immediately preceding stroke were as follows: 46% no change, 27% monotonic decrease, and 27% non-monotonic variation. When changes were measured with respect to the first stroke, 54% of nighttime flashes showed monotonic decrease and 46% no change. Ionospheric reflection height tends to increase with return-stroke peak current. The observed daytime effects can be explained by (a) the dependence of EMP penetration depth on source intensity, which decreases with stroke order, (b) additional ionization associated with elves, or (c) combination of (a) and (b) above.

  13. Flash-induced absorption spectroscopy studies of copper interaction with photosystem II in higher plants.

    PubMed

    Schröder, W P; Arellano, J B; Bittner, T; Barón, M; Eckert, H J; Renger, G

    1994-12-30

    Measurements of flash-induced absorption changes at 325, 436, and 830 nm and of oxygen evolution were performed in order to analyze in detail the inhibition of photosystem II (PS II) by Cu(II) in PS II membrane fragments from spinach. (a) The kinetics of P680+ reduction become markedly slower in the presence of 100 microM CuSO4. (b) The CuSO4-induced kinetics of P680+ reduction are dominated by a 140-160-microsecond decay. (c) The extent of these 140-160-microsecond kinetics, normalized to the overall decay, remains virtually unaffected by addition of the exogenous PS II donor, NH2OH. (d) In thoroughly dark-adapted samples the CuSO4-induced 140-160-microsecond kinetics are already observed after the first flash and remain unchanged by a train of excitation flashes. (e) The extent of P680+ and QA- formation under repetitive flash excitation is not diminished by addition of 100 microM CuSO4. (f) The induction of microsecond kinetics of P680+ reduction at the expense of ns kinetics and the inhibition of the saturation rate of oxygen evolution exhibit the same dependence on CuSO4 concentration. (g) CuSO4 also transforms the 10-20-microsecond reduction of P680+ by TyrZ in Tris-washed PS II membrane fragments into 140-160-microsecond kinetics without any effect on the extent of flash-induced P680+ formation. These results unambiguously show that Cu(II) does not affect the charge separation (P680+QA-), but instead specifically modifies TyrZ and/or its micro environment so that the electron transfer to P680+ becomes blocked.

  14. Pathological proof of cellular death in radiofrequency ablation therapy and correlation with flash echo imaging--an experiment study.

    PubMed

    Fujiki, Kei

    2004-01-01

    The aims of this study were to clarify the geographic distribution of complete cell death in the radiofrequency ablated area in a porcine liver experiment, and to evaluate the efficacy of ultrasonography using contrast media in detecting the area of Radiofrequency-induced cell death. Radiofrequency ablation was performed at 3 sites in each liver in seven swine with a RF2000TM radiofrequency generator using an expandable type needle electrode. The ablation area was investigated histologically by Hematoxylin-Eosin staining and NADH staining. The area of radiofrequency-induced cell death was correlated to the ultrasonographic findings using contrast media, by means of contrast harmonic imaging, flash echo imaging-subtraction and flash echo imaging-power Doppler. The ablation area showed three distinct regions. Although the HE staining did not indicate necrosis, the NADH staining showed a complete loss of cellular activity in the inner and middle layers of the ablation area. However, in the outer layer cells displaying cellular integrity were intermingled with the necrotic cells, indicating that some of the cells in this layer had a chance to survive. Further, in some cases the outer layer of the ablated area had irregular margins. The flash-echo power-doppler images were accurately correlated in size and shape to the pathologically proved region of complete cell death in the radiofrequency-induced lesions. In the marginal part of the radiofrequency ablation area, cell death was incomplete. Flash echo imaging-power doppler was a useful and sensitive real time imaging technique for accurate evaluation of the region of complete cell death.

  15. Kinetics of the superoxide radical oxidation of(cobalt sepulchrate)(2+). A flash photolytic study

    SciTech Connect

    Bakac, A.; Espenson, J.H.; kCreaser, I.I.; Sargeson, A.M.

    1983-12-28

    The postulated formation of the superoxide radical anion, O/sub 2//sup -/-, as an intermediate in the reaction of Co(sep)/sup 2 +/ (sep = sepulchrate) with molecular oxygen has now been confirmed by a trapping reaction with Cu/sup 2 +/. In the absence of Cu/sup 2 +/, O/sub 2//sup -/-oxidizes a second Co(sep)/sup 2 +/ to Co(sep)/sup 3 +/. The latter reaction, studied directly by use of the flash photolytic technique, has at 25/sup 0/C a rate constant of (4.6+/-1.1) x 10/sup 7/M/sup -1/s/sup -1/, independent of pH in the range 11.3-12.6. Nitrogen perdeuteration yields d(N)/sup 6 -/Co(sep)/sup 2 +/, which reacts with O/sub 2/ at the same rate but with O/sub 2//sup -/ 2.1 times more slowly. The proposed mechanism of the O/sub 2//sup -/ reaction consists of the hydrogen atom abstraction from a N-H bond of Co(sep)/sup 2 +/ by O/sub 2//sup -/, followed by the rapid protonation of the products, Co/sup III/(sep-H)/sup 2 +/ and HO/sub 2/, to form Co(sep)/sup 3 +/ and H/sub 2/O/sub 2/. In contrast, the reaction between Co(sep)/sup 2 +/ and O/sub 2/, which shows no kinetic isotope effect, occurs by outer-sphere electron transfer.

  16. Photochemical transformations and laser flash photolysis studies of dibenzobarrelenes containing 1,2-dibenzoylalkene moieties

    SciTech Connect

    Kumar, C.V.; Murty, B.A.R.C.; Lahiri, S.; Chackachery, E.; Scaiano, J.C.; George, M.V.

    1984-12-14

    Phototransformations of the dibenzobarrelenes 10 = 11,12-dibenzoyl-9,10-dihydro-9,10-ethenoanthracene, 11 = 11,12-dibenzoyl-9,10-dihydro-9-methyl-9,10-ethenoanthracene, 23 = 11,12-dibenzoyl-9,10-dihydro-9,10-dimethyl-9,10-ethenoenthracene, prepared by the reaction of the appropriate anthracenes with dibenzoylacetylenes, are reported. Irradiation of 10 and 11 in solvents such as benzene, methanol, and acetone gave the corresponding dibenzosemibullvalenes, 17 = 8c, 8d-dibenzoyl-4b,8b,8c,8d-tetrahydrodibenzo(a,f)cyclopropa(c,d)- and 18, respectively, in good yields. These dibenzosemibullvalenes on catalytic hydrogenation using 5% Pd on charcoal gave the corresponding cyclopropane ring-opened products, 21 and 22, respectively. Irradiation of 23 in benzene gave a mixture of 2,3-dibenzoyl-2,3-dihydro-1,4-dimethyl-2,3-benzonaphthalene 27 (2%), 1,4-dibenzoyl-5,8-dimethyl-2,3:6,7-dibenzocyclo-octatetraene (24, 20%), the carbinol (45%), and benzoic acid (7%). Irradiation of 23 in methanol gave a mixture of 27 (25%), 24 (27%), and benzoic acid (8%). Laser flash photolysis (337.1 nm) of 10, 11, and 23 led to transient species, characterized by strong absorptions in the 300-650-nm region. These transients are due to the triplet states of the substrates, as established by quenching studies involving oxygen, di-tert-butylnitroxide, azulene, and ..beta..-carotene. Energy-transfer sensitization of 10, 11, and 23 by benzophenone in benzene also gave rise to the same transients, as formed under direct irradiation. The quantum yields of triplet formation (PHI/sub T/) were estimated to be high for 10 and 11 (approx. 1), whereas it is significantly lower for 23 (approx. 0.7). 24 references, 3 figures, 2 tables.

  17. Photoreduction of azaoxoisoaporphines by amines: laser flash and steady-state photolysis and pulse radiolysis studies.

    PubMed

    de la Fuente, Julio R; Aliaga, Christian; Cañete, Alvaro; Kciuk, Gabriel; Szreder, Tomasz; Bobrowski, Krzysztof

    2013-01-01

    Photoreduction of 7H-benzo[e]perimidin-7-one (3-AOIA, A1) and its 2-methyl derivative (2-Me-3-AOIA, A2) by non-H-donating amines (1,4-diazabicyclo[2.2.2]octane [DABCO]; 2,2,6,6-tetramethylpiperidine [TMP]), and a hydrogen-donating amine (triethylamine [TEA]), has been studied in deaerated neat acetonitrile solutions using laser flash photolysis (LFP) and steady-state photolysis. The triplet excited states of A1 and A2 were characterized by a strong absorption band with λmax = 440 nm and lifetimes of 20 and 27 μs respectively. In the presence of tertiary amines, both triplet excited states were quenched with rate constants close to the diffusional limit (kq ranged between 10(9) and 10(10) M(-1) s(-1)). The transient absorption spectra observed after quenching with DABCO and TMP were characterized by maxima located at 460 nm and broad shoulders in the range of 500-600 nm. These transient species are attributed to solvent-separated radical ion pairs and/or to isolated radical anions. In the presence of TEA, these transients undergo proton transfer, leading to the neutral hydrogenated radicals, protonated over the N1- and O-atoms. Transient absorption spectra of these transients were characterized by maxima located at 400 and 520 nm and 430 nm respectively. Additional support for these spectral assignments was provided by pulse radiolysis (PR) experiments in acetonitrile and 2-propanol solutions. © 2013 The American Society of Photobiology.

  18. The Electronically Steerable Flash Lidar: A NASA Facility Instrument for Ecological Studies

    NASA Astrophysics Data System (ADS)

    Ramond, T.; Weimer, C. S.; Lefsky, M. A.; Duong, H.

    2011-12-01

    The Electronically Steerable Flash Lidar (ESFL) is a lidar concept created at Ball Aerospace and developed in conjunction with NASA. It represents a new paradigm for airborne or spaceborne lidar remote sensing. Instead of the mechanical scanning common to airborne lidars, or the fixed beam approach found in spaceborne lidars, ESFL allows the number and position of transmitted beams to vary shot-to-shot. This is done using an acousto-optic beam deflector that splits a single laser beam into N output beams, where N and the position of beam N on the ground can be reconfigured in real time electronically. This transmitter concept is coupled with a Flash Focal Plane Array (FFPA), a pixilated detector where every pixel delivers a time-resolved intensity waveform, thus allowing lidar imaging. The ESFL enables several jumps in capability for remote sensing of ecosystems. Multiple spatial scales can be probed simultaneously or within the same flight transect because beam spacings can be varied in real time. This means contiguous beams can be applied to regions where smaller scale variability needs to be probed, and in areas where maximum across-track coverage is needed, those beams are spread out. Furthermore, each beam can be projected onto multiple pixels, allowing one to collect a waveform over multiple length scales simultaneously. The electronic interface with the AOBD means that the transmitted pattern can respond to any of a multitude of inputs. The ESFL can interface with another forward-looking sensor, such as a hyperspectral instrument or another lidar or a digital camera. The data from that second sensor could be used to direct the ESFL observation toward, for example, an area with a specific spectral signature, or an area free from clouds. The ESFL concept was designed with a path to space in mind, but an airborne version has been built and tested on aircraft. The work continues under a NASA Airborne Instrument Technology Transition (AITT) grant designed to

  19. NASA Jet Noise Research

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda

    2016-01-01

    The presentation highlights NASA's jet noise research for 2016. Jet-noise modeling efforts, jet-surface interactions results, acoustic characteristics of multi-stream jets, and N+2 Supersonic Aircraft system studies are presented.

  20. An experimental study of the glottal jet

    NASA Astrophysics Data System (ADS)

    Jasikova, Darina; Sidlof, Petr; Kotek, Michal; Kopecky, Vaclav

    2016-03-01

    The paper presents results of the flow field analysis in a static scaled model of human larynx. Here we are focused on the effect of the nozzle gap parameter and the incoming flow velocity. The study is performed in the aerodynamic channel using the PIV technique.

  1. An Experimental Study of Plunging Liquid Jet Induced Air Carryunder and Dispersion

    DTIC Science & Technology

    1991-12-24

    jet . This jet impacted at 90* a pool of water and, when a threshold velocity was exceeded, it was observed that the plunging liquid jet caused air ... Entrainment by Plunging Laminar Liquid Jets ," AIChE Journal, Vol. 12, No. 3, 563, 1966. McKeogh, E.J. and Ervine, D.A., " Air Entrainment Rate and Diffusion...transmit the fourth quarterly report for ONR grant N00014-91-J-1271, "An Experimental Study of Plunging Liquid

  2. Feasibility Study of Acupuncture for Reducing Sleep Disturbances and Hot Flashes in Post-Menopausal Breast Cancer Survivors

    PubMed Central

    Carpenter, Janet S.; Zhong, Xin; Johnstone, Peter A. S.

    2011-01-01

    Objectives This was a feasibility study of a tailored acupuncture intervention in post-menopausal breast cancer survivors (BCS) reporting sleep disturbances and hot flashes. Objectives were: 1) to describe patterns of acupuncture point use, 2) evaluate outcome expectancy, credibility, and acceptability relative to the intervention; and 3) evaluate patterns of symptom change over time. Design Single group, non-randomized, quasi-experimental 8-week study. Sample/Setting Ten BCS with both sleep disturbances and hot flashes were referred to any of 4 Midwestern community acupuncturists. Methods Assessments were done at baseline (weeks 1, 2), during treatment (weeks 3, 4), and after treatment (week 5, 8). Acupuncture treatment was tailored to the individual by community acupuncturists and provided as 3 sessions within a 2 week period (weeks 3, 4). Patients wore a wrist actigraph during weeks 1, 2, 3, 4, 5, and 8 and a sternal skin conductance monitor for 24 consecutive hours during weeks 1, 2, 3, 4, 5, and 8. Subjective data were obtained by questionnaire at weeks 1, 2, 3, 4, 5 and 8. Findings Women were a mean age of 53, with an average 6.75 years since diagnosis. A mean of 10 needles were used per session with the most common points located in the LU or lung meridian. BCS had high expectancy that acupuncture would decrease their symptoms, believed it was a credible treatment and felt it an acceptable form of treatment. Three significant patterns of symptom change were noted from baseline: an increase in the number of minutes it took to fall asleep after treatment (from week 5 to 8, (p=.04); a decrease in the percentage of time awake after sleep onset from baseline to follow-up 2 (week 8) (p=0.05); and a decrease in number of hot flashes from baseline to follow-up 1 (week 5) (p=0.02). Implications for Nursing Findings may be used by Clinical Nurse Specialists to consider recommending acupuncture to improve sleep and reduce hot flashes in BCS. Conclusions Acupuncture

  3. A Study Of Leonid Impact Flashes On The Moon In 2004

    NASA Astrophysics Data System (ADS)

    Ortiz, J. L.; Aceituno, F. J.; Santos-Sanz, P.; Quesada, J. A.

    2005-08-01

    In November 2004 the lunar phase was adequate to observe lunar impact flashes at the time of the Leonid meteor shower, as it was the case in 1999 and 2001, because a large number of meteoroidal impacts were expected to hit the night part of the Moon visible from Earth. We again arranged a special multisite observing campaign with telescopes aiming at the night part of the Moon in order to detect and analyze such flashes. In this paper we report our unambiguous detections, our computations of the energy released in each impact, their locations on the Moon and possible inferences on crater sizes. Those fresh craters might perhaps be observable from SMART-1. Some implications on Leonid meteor fluxes on Earth and size distribution of the particles are also discussed. This research was supported by the spanish AYA-2002-0382 project. FEDER funds are also acknowledged.

  4. Prevalence and Predictors of Night Sweats, Day Sweats, and Hot Flashes in Older Primary Care Patients: An OKPRN Study

    PubMed Central

    Mold, James W.; Roberts, Michelle; Aboshady, Hesham M.

    2004-01-01

    PURPOSE We wanted to estimate the prevalence of night sweats, day sweats, and hot flashes in older primary care patients and identify associated factors. METHODS We undertook a cross-sectional study of patients older than 64 years recruited from the practices of 23 family physicians. Variables included sociodemographic information, health habits, chronic medical problems, symptoms, quality of life, and the degree to which patients were bothered by night sweats, daytime sweating, and hot flashes. RESULTS Among the 795 patients, 10% reported being bothered by night sweats, 9% by day sweats, and 8% by hot flashes. Eighteen percent reported at least 1 of these symptoms. The 3 symptoms were strongly correlated. Factors associated with night sweats in the multivariate models were age (odds ratio [OR] 0.94/y; 95% confidence interval [CI], 0.89–0.98), fever (OR 12.60; 95% CI, 6.58–24.14), muscle cramps (OR 2.84; 95% CI, 1.53–5.24), numbness of hands and feet (OR 3.34; 95% CI, 1.92–5.81), impaired vision (OR 2.45; 95% CI, 1.41–4.27), and hearing loss (OR 1.84; 95% CI, 1.03–3.27). Day sweats were associated with fever (OR 4.10; 95% CI, 2.14–7.87), restless legs (OR 3.22; 95% CI, 1.76–5.89), lightheadedness (OR 2.24; 95% CI, 1.30–3.88), and diabetes (OR 2.19; 95% CI, 1.22–3.92). Hot flashes were associated with nonwhite race (OR 3.10; 95% CI, 1.60–5.98), fever (OR 3.98; 95% CI, 1.97–8.04), bone pain (OR 2.31; CI 95%: 1.30–4.08), impaired vision (OR 2.12; 95% CI, 1.19–3.79), and nervous spells (OR 1.87; 95% CI, 1.01–3.46). All 3 symptoms were associated with reduced quality of life. CONCLUSION Many older patients are bothered by night sweats, day sweats, and hot flashes. Though these symptoms are similar and related, they have somewhat different associations with other variables. Clinical evaluation should include questions about febrile illnesses, sensory deficits, anxiety, depression, pain, muscle cramps, and restless legs syndrome. PMID

  5. Prevalence and predictors of night sweats, day sweats, and hot flashes in older primary care patients: an OKPRN study.

    PubMed

    Mold, James W; Roberts, Michelle; Aboshady, Hesham M

    2004-01-01

    We wanted to estimate the prevalence of night sweats, day sweats, and hot flashes in older primary care patients and identify associated factors. We undertook a cross-sectional study of patients older than 64 years recruited from the practices of 23 family physicians. Variables included sociodemographic information, health habits, chronic medical problems, symptoms, quality of life, and the degree to which patients were bothered by night sweats, daytime sweating, and hot flashes. Among the 795 patients, 10% reported being bothered by night sweats, 9% by day sweats, and 8% by hot flashes. Eighteen percent reported at least 1 of these symptoms. The 3 symptoms were strongly correlated. Factors associated with night sweats in the multivariate models were age (odds ratio [OR] 0.94/y; 95% confidence interval [CI], 0.89-0.98), fever (OR 12.60; 95% CI, 6.58-24.14), muscle cramps (OR 2.84; 95% CI, 1.53-5.24), numbness of hands and feet (OR 3.34; 95% CI, 1.92-5.81), impaired vision (OR 2.45; 95% CI, 1.41-4.27), and hearing loss (OR 1.84; 95% CI, 1.03-3.27). Day sweats were associated with fever (OR 4.10; 95% CI, 2.14-7.87), restless legs (OR 3.22; 95% CI, 1.76-5.89), lightheadedness (OR 2.24; 95% CI, 1.30-3.88), and diabetes (OR 2.19; 95% CI, 1.22-3.92). Hot flashes were associated with nonwhite race (OR 3.10; 95% CI, 1.60-5.98), fever (OR 3.98; 95% CI, 1.97-8.04), bone pain (OR 2.31; CI 95%: 1.30-4.08), impaired vision (OR 2.12; 95% CI, 1.19-3.79), and nervous spells (OR 1.87; 95% CI, 1.01-3.46). All 3 symptoms were associated with reduced quality of life. Many older patients are bothered by night sweats, day sweats, and hot flashes. Though these symptoms are similar and related, they have somewhat different associations with other variables. Clinical evaluation should include questions about febrile illnesses, sensory deficits, anxiety, depression, pain, muscle cramps, and restless legs syndrome.

  6. Ketone photochemistry on solid silica. A diffuse reflectance laser flash photolysis study

    NASA Astrophysics Data System (ADS)

    Turro, Nicholas J.; Gould, Ian R.; Zimmt, Matthew B.; Cheng, Chen-Chih

    1985-09-01

    Using diffuse reflectance laser flash photolysis, the lifetimes of the triplet states of valerophenone and diphenylbutyrophenone adsorbed on solid silica have been determined to be 0.3 and 0.9 μs respectively. These lifetimes are at least two orders of magnitude greater than those found in homogeneous solution. Quenching of the triplet states by gas-phase oxygen and butadiene is observed.

  7. FLASH MHD simulations of experiments that study shock-generated magnetic fields

    NASA Astrophysics Data System (ADS)

    Tzeferacos, P.; Fatenejad, M.; Flocke, N.; Graziani, C.; Gregori, G.; Lamb, D. Q.; Lee, D.; Meinecke, J.; Scopatz, A.; Weide, K.

    2015-12-01

    We summarize recent additions and improvements to the high energy density physics capabilities in FLASH, highlighting new non-ideal magneto-hydrodynamic (MHD) capabilities. We then describe 3D Cartesian and 2D cylindrical FLASH MHD simulations that have helped to design and analyze experiments conducted at the Vulcan laser facility. In these experiments, a laser illuminates a carbon rod target placed in a gas-filled chamber. A magnetic field diagnostic (called a Bdot) employing three very small induction coils is used to measure all three components of the magnetic field at a chosen point in space. The simulations have revealed that many fascinating physical processes occur in the experiments. These include megagauss magnetic fields generated by the interaction of the laser with the target via the Biermann battery mechanism, which are advected outward by the vaporized target material but decrease in strength due to expansion and resistivity; magnetic fields generated by an outward expanding shock via the Biermann battery mechanism; and a breakout shock that overtakes the first wave, the contact discontinuity between the target material and the gas, and then the initial expanding shock. Finally, we discuss the validation and predictive science we have done for this experiment with FLASH.

  8. [Study on the discharge properties of xeon flash lamp and experimental measurement].

    PubMed

    Zhao, You-Quan; Miao, Pei-Liang; He, Feng; Gu, Jian; Zhai, Rui-Wei

    2014-07-01

    The Xenon flash lamp is a new type of light source for analytical instrument. The present paper analyzed the discharge process of xenon flash lamp, presented the discharge test system, and conducted experimental measurement of the voltage, current and optical pulse signal in the process of discharge. The results show that in the preliminary discharge, the free electron concentration was at a low level, so the energy was at a low level, then following the gas discharge, numerous free electrons formed in the lamp, resultin in the increase in the concentration of free electrons, therefore discharge current rised rapidly and voltage reduced. The lamp released photons to generate light pulse in the moment of ionic recombination, The pulse xenon lamp light energy output and spectral characteristic is related to electron energy in recombination and combination level of xenon, if the input energy and the energy consumption of the xenon lamp is inconsistent, it will lead to repeated capacitor charging and discharging and produce oscillation waveform. This paper is very useful for understanding the process of xenon lamp discharge, optimizing the driver circuit and the production of xenon flash lamp.

  9. Lunar Impact Flash Locations

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

    A bright impact flash detected by the NASA Lunar Impact Monitoring Program in March 2013 brought into focus the importance of determining the impact flash location. A process for locating the impact flash, and presumably its associated crater, was developed using commercially available software tools. The process was successfully applied to the March 2013 impact flash and put into production on an additional 300 impact flashes. The goal today: provide a description of the geolocation technique developed.

  10. Estimation of the Relative Severity of Floods in Small Ungauged Catchments for Preliminary Observations on Flash Flood Preparedness: A Case Study in Korea

    PubMed Central

    Kim, Eung Seok; Choi, Hyun Il

    2012-01-01

    An increase in the occurrence of sudden local flooding of great volume and short duration has caused significant danger and loss of life and property in Korea as well as many other parts of the World. Since such floods usually accompanied by rapid runoff and debris flow rise quite quickly with little or no advance warning to prevent flood damage, this study presents a new flash flood indexing methodology to promptly provide preliminary observations regarding emergency preparedness and response to flash flood disasters in small ungauged catchments. Flood runoff hydrographs are generated from a rainfall-runoff model for the annual maximum rainfall series of long-term observed data in the two selected small ungauged catchments. The relative flood severity factors quantifying characteristics of flood runoff hydrographs are standardized by the highest recorded maximum value, and then averaged to obtain the flash flood index only for flash flood events in each study catchment. It is expected that the regression equations between the proposed flash flood index and rainfall characteristics can provide the basis database of the preliminary information for forecasting the local flood severity in order to facilitate flash flood preparedness in small ungauged catchments. PMID:22690208

  11. Estimation of the relative severity of floods in small ungauged catchments for preliminary observations on flash flood preparedness: a case study in Korea.

    PubMed

    Kim, Eung Seok; Choi, Hyun Il

    2012-04-01

    An increase in the occurrence of sudden local flooding of great volume and short duration has caused significant danger and loss of life and property in Korea as well as many other parts of the World. Since such floods usually accompanied by rapid runoff and debris flow rise quite quickly with little or no advance warning to prevent flood damage, this study presents a new flash flood indexing methodology to promptly provide preliminary observations regarding emergency preparedness and response to flash flood disasters in small ungauged catchments. Flood runoff hydrographs are generated from a rainfall-runoff model for the annual maximum rainfall series of long-term observed data in the two selected small ungauged catchments. The relative flood severity factors quantifying characteristics of flood runoff hydrographs are standardized by the highest recorded maximum value, and then averaged to obtain the flash flood index only for flash flood events in each study catchment. It is expected that the regression equations between the proposed flash flood index and rainfall characteristics can provide the basis database of the preliminary information for forecasting the local flood severity in order to facilitate flash flood preparedness in small ungauged catchments.

  12. A study of jet handedness at the Z{sup 0} resonance

    SciTech Connect

    Masuda, H.; SLD Collaboration

    1993-10-01

    We present a preliminary study of jet handedness is hadronic decays of Z{sup 0} bosons measured in the SLD experiment at the SLAC Linear Collider (SLC). Following the proposal of Nachtman and Efremov et al., we defined a scalar quantity for each hadronic jet and measured the sign asymmetry (jet handedness) of this quantity for samples of quark jets and antiquark jets, which are expected to be oppositely polarized in Z{sup 0} decays. From our preliminary study, no evidence for a significantly non-zero handedness was observed. Assuming standard model values of quark polarizations, we set an upper limit on the analyzing power of our handedness method.

  13. Study and development of acoustic treatment for jet engine tailpipes

    NASA Technical Reports Server (NTRS)

    Nelson, M. D.; Linscheid, L. L.; Dinwiddie, B. A., III; Hall, O. J., Jr.

    1971-01-01

    A study and development program was accomplished to attenuate turbine noise generated in the JT3D turbofan engine. Analytical studies were used to design an acoustic liner for the tailpipe. Engine ground tests defined the tailpipe environmental factors and laboratory tests were used to support the analytical studies. Furnace-brazed, stainless steel, perforated sheet acoustic liners were designed, fabricated, installed, and ground tested in the tailpipe of a JT3D engine. Test results showed the turbine tones were suppressed below the level of the jet exhaust for most far field polar angles.

  14. Cytogenetic studies in mice treated with the jet fuels, Jet-A and JP-8.

    PubMed

    Vijayalaxmi, V; Kligerman, A D; Prihoda, T J; Ullrich, S E

    2004-01-01

    The genotoxic potential of the jet fuels, Jet-A and JP-8, were examined in mice treated on the skin with a single dose of 240 mg/mouse. Peripheral blood smears were prepared at the start of the experiment (t = 0), and at 24, 48 and 72 h following treatment with jet fuels. Femoral bone marrow smears were made when all animals were sacrificed at 72 h. In both tissues, the extent of genotoxicity was determined from the incidence of micronuclei (MN) in polychromatic erythrocytes. The frequency of MN in the peripheral blood of mice treated with Jet-A and JP-8 increased over time and reached statistical significance at 72 h, as compared with concurrent control animals. The incidence of MN was also higher in bone marrow cells of mice exposed to Jet-A and JP-8 as compared with controls. Thus, at the dose tested, a small but significant genotoxic effect of jet fuels was observed in the blood and bone marrow cells of mice treated on the skin.

  15. A model for straight and helical solar jets. II. Parametric study of the plasma beta

    NASA Astrophysics Data System (ADS)

    Pariat, E.; Dalmasse, K.; DeVore, C. R.; Antiochos, S. K.; Karpen, J. T.

    2016-11-01

    Context. Jets are dynamic, impulsive, well-collimated plasma events that develop at many different scales and in different layers of the solar atmosphere. Aims: Jets are believed to be induced by magnetic reconnection, a process central to many astrophysical phenomena. Within the solar atmosphere, jet-like events develop in many different environments, e.g., in the vicinity of active regions, as well as in coronal holes, and at various scales, from small photospheric spicules to large coronal jets. In all these events, signatures of helical structure and/or twisting/rotating motions are regularly observed. We aim to establish that a single model can generally reproduce the observed properties of these jet-like events. Methods: Using our state-of-the-art numerical solver ARMS, we present a parametric study of a numerical tridimensional magnetohydrodynamic (MHD) model of solar jet-like events. Within the MHD paradigm, we study the impact of varying the atmospheric plasma β on the generation and properties of solar-like jets. Results: The parametric study validates our model of jets for plasma β ranging from 10-3 to 1, typical of the different layers and magnetic environments of the solar atmosphere. Our model of jets can robustly explain the generation of helical solar jet-like events at various β ≤ 1. We introduces the new result that the plasma β modifies the morphology of the helical jet, explaining the different observed shapes of jets at different scales and in different layers of the solar atmosphere. Conclusions: Our results enable us to understand the energisation, triggering, and driving processes of jet-like events. Our model enables us to make predictions of the impulsiveness and energetics of jets as determined by the surrounding environment, as well as the morphological properties of the resulting jets.

  16. Simulation and Experimental Study on Cavitating Water Jet Nozzle

    NASA Astrophysics Data System (ADS)

    Zhou, Wei; He, Kai; Cai, Jiannan; Hu, Shaojie; Li, Jiuhua; Du, Ruxu

    2017-01-01

    Cavitating water jet technology is a new kind of water jet technology with many advantages, such as energy-saving, efficient, environmentally-friendly and so on. Based on the numerical simulation and experimental verification in this paper, the research on cavitating nozzle has been carried out, which includes comparison of the cleaning ability of the cavitating jet and the ordinary jet, and comparison of cavitation effects of different structures of cavitating nozzles.

  17. Jet-A reaction mechanism study for combustion application

    NASA Technical Reports Server (NTRS)

    Lee, Chi-Ming; Kundu, Krishna; Acosta, Waldo

    1991-01-01

    Simplified chemical kinetic reaction mechanisms for the combustion of Jet A fuel was studied. Initially, 40 reacting species and 118 elementary chemical reactions were chosen based on a literature review. Through a sensitivity analysis with the use of LSENS General Kinetics and Sensitivity Analysis Code, 16 species and 21 elementary chemical reactions were determined from this study. This mechanism is first justified by comparison of calculated ignition delay time with the available shock tube data, then it is validated by comparison of calculated emissions from the plug flow reactor code with in-house flame tube data.

  18. Jet-A reaction mechanism study for combustion application

    NASA Technical Reports Server (NTRS)

    Lee, Chi-Ming; Kundu, Krishna; Acosta, Waldo

    1991-01-01

    Simplified chemical kinetic reaction mechanisms for the combustion of Jet A fuel are studied. Initially 40 reacting species and 118 elementary chemical reactions were chosen based on the literature review of previous works. Through a sensitivity analysis with the use of LSENS General Kinetics and Sensitivity Analysis Code, 16 species and 21 elementary chemical reactions were determined from this study. This mechanism is first justified by comparison of calculated ignition delay time with available shock tube data, then it is validated by comparison of calculated emissions from plug flow reactor code with in-house flame tube data.

  19. Jet-A reaction mechanism study for combustion application

    NASA Technical Reports Server (NTRS)

    Lee, Chi-Ming; Kundu, Krishna; Acosta, Waldo

    1991-01-01

    Simplified chemical kinetic reaction mechanisms for the combustion of Jet A fuel are studied. Initially 40 reacting species and 118 elementary chemical reactions were chosen based on the literature review of previous works. Through a sensitivity analysis with the use of LSENS General Kinetics and Sensitivity Analysis Code, 16 species and 21 elementary chemical reactions were determined from this study. This mechanism is first justified by comparison of calculated ignition delay time with available shock tube data, then it is validated by comparison of calculated emissions from plug flow reactor code with in-house flame tube data.

  20. Fuzzy jets

    NASA Astrophysics Data System (ADS)

    Mackey, Lester; Nachman, Benjamin; Schwartzman, Ariel; Stansbury, Conrad

    2016-06-01

    Collimated streams of particles produced in high energy physics experiments are organized using clustering algorithms to form jets. To construct jets, the experimental collaborations based at the Large Hadron Collider (LHC) primarily use agglomerative hierarchical clustering schemes known as sequential recombination. We propose a new class of algorithms for clustering jets that use infrared and collinear safe mixture models. These new algorithms, known as fuzzy jets, are clustered using maximum likelihood techniques and can dynamically determine various properties of jets like their size. We show that the fuzzy jet size adds additional information to conventional jet tagging variables in boosted topologies. Furthermore, we study the impact of pileup and show that with some slight modifications to the algorithm, fuzzy jets can be stable up to high pileup interaction multiplicities.

  1. Fuzzy jets

    DOE PAGES

    Mackey, Lester; Nachman, Benjamin; Schwartzman, Ariel; ...

    2016-06-01

    Collimated streams of particles produced in high energy physics experiments are organized using clustering algorithms to form jets . To construct jets, the experimental collaborations based at the Large Hadron Collider (LHC) primarily use agglomerative hierarchical clustering schemes known as sequential recombination. We propose a new class of algorithms for clustering jets that use infrared and collinear safe mixture models. These new algorithms, known as fuzzy jets , are clustered using maximum likelihood techniques and can dynamically determine various properties of jets like their size. We show that the fuzzy jet size adds additional information to conventional jet tagging variablesmore » in boosted topologies. Furthermore, we study the impact of pileup and show that with some slight modifications to the algorithm, fuzzy jets can be stable up to high pileup interaction multiplicities.« less

  2. Fuzzy jets

    SciTech Connect

    Mackey, Lester; Nachman, Benjamin; Schwartzman, Ariel; Stansbury, Conrad

    2016-06-01

    Collimated streams of particles produced in high energy physics experiments are organized using clustering algorithms to form jets . To construct jets, the experimental collaborations based at the Large Hadron Collider (LHC) primarily use agglomerative hierarchical clustering schemes known as sequential recombination. We propose a new class of algorithms for clustering jets that use infrared and collinear safe mixture models. These new algorithms, known as fuzzy jets , are clustered using maximum likelihood techniques and can dynamically determine various properties of jets like their size. We show that the fuzzy jet size adds additional information to conventional jet tagging variables in boosted topologies. Furthermore, we study the impact of pileup and show that with some slight modifications to the algorithm, fuzzy jets can be stable up to high pileup interaction multiplicities.

  3. Experimental and Numerical Studies for Soot Formation in Laminar Coflow Diffusion Flames of Jet A-1 and Synthetic Jet Fuels

    NASA Astrophysics Data System (ADS)

    Saffaripour, Meghdad

    In the present doctoral thesis, fundamental experimental and numerical studies are conducted for the laminar, atmospheric pressure, sooting, coflow diffusion flames of Jet A-1 and synthetic jet fuels. The first part of this thesis presents a comparative experimental study for Jet A-1, which is a widely used petroleum-based fuel, and four synthetically produced alternative jet fuels. The main goals of this part of the thesis are to compare the soot emission levels of the alternative fuels to those of a standard fuel, Jet A-1, and to determine the effect of fuel chemical composition on soot formation characteristics. To achieve these goals, experimental measurements are constructed and performed for flame temperature, soot concentration, soot particle size, and soot aggregate structure in the flames of pre-vaporized jet fuels. The results show that a considerable reduction in soot production, compared to the standard fuel, can be obtained by using synthetic fuels which will help in addressing future regulations. A strong correlation between the aromatic content of the fuels and the soot concentration levels in the flames is observed. The second part of this thesis presents the development and experimental validation of a fully-coupled soot formation model for laminar coflow jet fuel diffusion flames. The model is coupled to a detailed kinetic mechanism to predict the chemical structure of the flames and soot precursor concentrations. This model also provides information on size and morphology of soot particles. The flames of a three-component surrogate for Jet A-1, a three-component surrogate for a synthetic jet fuel, and pure n-decane are simulated using this model. Concentrations of major gaseous species and flame temperatures are well predicted by the model. Soot volume fractions are predicted reasonably well everywhere in the flame, except near the flame centerline where soot concentrations are underpredicted by a factor of up to five. There is an excellent

  4. An experimental study of the noise generating mechanisms in supersonic jets

    NASA Technical Reports Server (NTRS)

    Mclaughlin, D. K.

    1979-01-01

    Flow fluctuation measurements with normal and X-wire hot-wire probes and acoustic measurements with a traversing condenser microphone were carried out in small air jets in the Mach number range from M = 0.9 to 2.5. One of the most successful studies involved a moderate Reynolds number M = 2.1 jet. The large scale turbulence properties in the jet, and the noise radiation were characterized. A parallel study involved similar measurements on a low Reynolds number M = 0.9 jet. These measurements show that there are important differences in the noise generation process of the M = 0.9 jet in comparison with low supersonic Mach number (M = 1.4) jets. Problems encounted while performing X-wire measurements in low Reynolds number jets of M = 2.1 and 2.5, and in installing a vacuum pump are discussed.

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

    PubMed

    Bietti, Massimo; Salamone, Michela

    2005-12-09

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

  6. Native point defect formation in flash sintered ZnO studied by depth-resolved cathodoluminescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Gao, Hantian; Asel, Thaddeus J.; Cox, Jon W.; Zhang, Yuanyao; Luo, Jian; Brillson, L. J.

    2016-09-01

    Depth-resolved cathodoluminescence spectroscopy studies of flash sintered ZnO reveal that thermal runaway induces the formation of native point defects inside individual grains. Defects associated with oxygen vacancies (VO) form preferentially, contributing additional donors that increase conductivity within the grains of the polycrystalline material. Hyperspectral imaging of the granular cross sections shows filaments of increased VO following thermal runaway between the capacitor anode and cathode, supporting a heating mechanism localized on a granular scale. Within the grains, these defects form preferentially inside rather than at their boundaries, further localizing the dominant heating mechanism.

  7. Bitopertin in Negative Symptoms of Schizophrenia-Results From the Phase III FlashLyte and DayLyte Studies.

    PubMed

    Bugarski-Kirola, Dragana; Blaettler, Thomas; Arango, Celso; Fleischhacker, Wolfgang W; Garibaldi, George; Wang, Alice; Dixon, Mark; Bressan, Rodrigo A; Nasrallah, Henry; Lawrie, Stephen; Napieralski, Julie; Ochi-Lohmann, Tania; Reid, Carol; Marder, Stephen R

    2017-07-01

    There is currently no standard of care for treatment of negative symptoms of schizophrenia, although some previous results with glutamatergic agonists have been promising. Three (SunLyte [WN25308], DayLyte [WN25309], and FlashLyte [NN25310]) phase III, multicenter, randomized, 24-week, double-blind, parallel-group, placebo-controlled studies evaluated the efficacy and safety of adjunctive bitopertin in stable patients with persistent predominant negative symptoms of schizophrenia treated with antipsychotics. SunLyte met the prespecified criteria for lack of efficacy and was declared futile. Key inclusion criteria were age ≥18 years, DSM-IV-TR diagnosis of schizophrenia, score ≥40 on the sum of the 14 Positive and Negative Syndrome Scale negative symptoms and disorganized thought factors, unaltered antipsychotic treatment, and clinical stability. Following a 4-week prospective stabilization period, patients were randomly assigned 1:1:1 to bitopertin (5 mg and 10 mg [DayLyte] and 10 mg and 20 mg [FlashLyte]) or placebo once daily for 24 weeks. The primary efficacy end point was mean change from baseline in Positive and Negative Syndrome Scale negative symptom factor score at week 24. The intent-to-treat population in DayLyte and FlashLyte included 605 and 594 patients, respectively. At week 24, mean change from baseline showed improvement in all treatment arms but no statistically significant separation from placebo in Positive and Negative Syndrome Scale negative symptom factor score and all other end points. Bitopertin was well tolerated. These studies provide no evidence for superior efficacy of adjunctive bitopertin in any of the doses tested over placebo in patients with persistent predominant negative symptoms of schizophrenia. Copyright © 2017. Published by Elsevier Inc.

  8. An Experimental and CFD Study of a Supersonic Coaxial Jet

    NASA Technical Reports Server (NTRS)

    Cutler, A. D.; White, J. A.

    2001-01-01

    A supersonic coaxial jet facility is designed and experimental data are acquired suitable for the validation of CFD codes employed in the analysis of high-speed air-breathing engines. The center jet is of a light gas, the coflow jet is of air, and the mixing layer between them is compressible. The jet flow field is characterized using schlieren imaging, surveys with pitot, total temperature and gas sampling probes, and RELIEF velocimetry. VULCAN, a structured grid CFD code, is used to solve for the nozzle and jet flow, and the results are compared to the experiment for several variations of the kappa - omega turbulence model

  9. Time-Resolved Imaging Study of Jetting Dynamics during Laser Printing of Viscoelastic Alginate Solutions.

    PubMed

    Zhang, Zhengyi; Xiong, Ruitong; Mei, Renwei; Huang, Yong; Chrisey, Douglas B

    2015-06-16

    Matrix-assisted pulsed-laser evaporation direct-write (MAPLE DW) has been successfully implemented as a promising laser printing technology for various fabrication applications, in particular, three-dimensional bioprinting. Since most bioinks used in bioprinting are viscoelastic, it is of importance to understand the jetting dynamics during the laser printing of viscoelastic fluids in order to control and optimize the laser printing performance. In this study, MAPLE DW was implemented to study the jetting dynamics during the laser printing of representative viscoelastic alginate bioinks and evaluate the effects of operating conditions (e.g., laser fluence) and material properties (e.g., alginate concentration) on the jet formation performance. Through a time-resolved imaging approach, it is found that when the laser fluence increases or the alginate concentration decreases, the jetting behavior changes from no material transferring to well-defined jetting to well-defined jetting with an initial bulgy shape to jetting with a bulgy shape to pluming/splashing. For the desirable well-defined jetting regimes, as the laser fluence increases, the jet velocity and breakup length increase while the breakup time and primary droplet size decrease. As the alginate concentration increases, the jet velocity and breakup length decrease while the breakup time and primary droplet size increase. In addition, Ohnesorge, elasto-capillary, and Weber number based phase diagrams are presented to better appreciate the dependence of jetting regimes on the laser fluence and alginate concentration.

  10. A microstructural study of flash welded and aged 6061 and 6013 aluminum alloys

    SciTech Connect

    Barbosa, C.; Dille, J.; Delplancke, J.-L.; Rebello, J.M.A.

    2006-09-15

    Extruded, flash welded and artificially aged 6061 and 6013 aluminum alloys were analyzed with the use of techniques such as transmission electron microscopy (TEM) imaging, selected area electron diffraction (SAD) and X-ray energy-dispersive spectroscopy (EDS) in order to identify the precipitates present in both alloys. Vickers microindentation hardness measurements were performed at different distances from the weld interface. The results show a small decrease in hardness near the 6013 alloy weld interface. On the other hand, there is an important hardness drop near the 6061 weld interface. This drop can be explained by a lack of fine structural precipitation during the aging treatment in the 6061 weld interface zone.

  11. ATOMIC BEAM STUDIES IN THE RHIC H-JET POLARIMETER.

    SciTech Connect

    MAKDISI,Y.; ZELENSKI,A.; GRAHAM,D.; KOKHANOVSKI,S.; MAHLER,G.; NASS,A.; RITTER,J.; ZUBETS,V.; ET AL.

    2005-01-28

    The results of atomic beam production studies are presented. Improved cooling of the atoms before jet formation in the dissociator cold nozzle apparently reduces the atomic beam velocity spread and improves beam focusing conditions. A carefully designed sextupole separating (and focusing) magnet system takes advantage of the high brightness source. As a result a record beam intensity of a 12.4 {center_dot} 10{sup 16} atoms/s was obtained within 10 mm acceptance at the collision point. The results of the polarization dilution factor measurements (by the hydrogen molecules at the collision point) are also presented.

  12. Numerical Study of Noise Characteristics in Overexpanded Jet Flows

    DTIC Science & Technology

    2015-08-05

    study of shock-cell noise in underexpanded supersonic jets”, AIAA 2013-2080 [17]. Tam, C. K. W., Viswanathan, K., K. K. Ahuja And J. Panda , “The sources...Suda, H., Manning, T. A., Kaji, S., “Transition of Oscillation Modes of Rectangular Supersonic Jet in Screech”, AIAA-93-4323. [24]. Panda , J., “Shock...1998, pp. 45–106. [28]. Panda , J., “An Experimental Investigation of Screech Noise Generation,” Journal of Fluid Mechanics, 1999, Vol. 378, pp. 71–96

  13. A numerical and experimental study of coaxial jets

    NASA Technical Reports Server (NTRS)

    Nikjooy, M.; Karki, K. C.; Mongia, H. C.; Mcdonell, V. G.; Samuelsen, G. S.

    1989-01-01

    An algebraic stress model and the standard k-epsilon model is applied to predict the mean and turbulence quantities for axisymmetric, nonswirling coaxial jets without confinement. To investigate the effects of numerical (false) diffusion on the predicted results, three different discretization schemes, namely, hybrid, power-law, and the flux-spline, are employed. In addition, an experimental study is conducted to provide data of good quality, especially near the inlet, for model assessment. The results show that the use of the algebraic stress model leads to better agreement between the numerical results and experimental data.

  14. Study on a liquid jet with cavitation bubbles

    NASA Astrophysics Data System (ADS)

    Kiyama, Akihito; Tagawa, Yoshiyuki

    2014-11-01

    A focused liquid jet is important in medical applications such as needle-free drug injection systems. A method for generating a liquid jet by laser-induced shock wave is proposed. However, there are some problems. Hence we examine another method for generating a focused liquid jet. We drop a liquid filled test tube on the rigid plate, leading to the emergence of a jet. Within certain experimental conditions, the jet velocity in our experiment agrees well with the semiempirical relation proposed by Tagawa et al. (2012, Phys. Rev. X) and Peters et al. (2013, J. Fluid Mech.). In other conditions, we find that the jet velocity remarkably increases. In order to understand the jet velocity increment, we use two high-speed cameras: One records motion of a jet. Another films cavitation bubbles inside a liquid bath. We categorize jets into three types based on their shape and the existence of cavitation bubbles. We find that the jet with cavitation bubbles is much faster than that without cavitation bubbles. For elucidating the mechanism of jet velocity increment, we discuss the effect of pressure wave, which propagates in a liquid bath. We propose a model for describing these phenomena and verify it experimentally. JSPS KAKENHI 26709007.

  15. Study and application of a high-pressure water jet multi-functional flow test system.

    PubMed

    Shi, Huaizhong; Li, Gensheng; Huang, Zhongwei; Li, Jingbin; Zhang, Yi

    2015-12-01

    As the exploration and development of oil and gas focus more and more on deeper formation, hydraulic issues such as high-pressure water jet rock breaking, wellbore multiphase flow law, cuttings carrying efficiency, and hydraulic fracturing technique during the drilling and completion process have become the key points. To accomplish related researches, a high-pressure water jet multi-functional flow test system was designed. The following novel researches are carried out: study of high-pressure water jet characteristics under confining pressure, wellbore multiphase flow regime, hydraulic pressure properties of down hole tools during jet fracturing and pulsed cavitation jet drilling, and deflector's friction in radial jet drilling. The validity and feasibility of the experimental results provided by the system with various test modules have proved its importance in the research of the high-pressure water jet and well completion technology.

  16. Experimental parametric study of jet vortex generators for flow separation control

    NASA Technical Reports Server (NTRS)

    Selby, Gregory

    1991-01-01

    A parametric wind-tunnel study was performed with jet vortex generators to determine their effectiveness in controlling flow separation associated with low-speed turbulence flow over a two-dimensional rearward-facing ramp. Results indicate that flow-separation control can be accomplished, with the level of control achieved being a function of jet speed, jet orientation (with respect to the free-stream direction), and orifice pattern (double row of jets vs. single row). Compared to slot blowing, jet vortex generators can provide an equivalent level of flow control over a larger spanwise region (for constant jet flow area and speed). Dye flow visualization tests in a water tunnel indicated that the most effective jet vortex generator configurations produced streamwise co-rotating vortices.

  17. Study and application of a high-pressure water jet multi-functional flow test system

    NASA Astrophysics Data System (ADS)

    Shi, Huaizhong; Li, Gensheng; Huang, Zhongwei; Li, Jingbin; Zhang, Yi

    2015-12-01

    As the exploration and development of oil and gas focus more and more on deeper formation, hydraulic issues such as high-pressure water jet rock breaking, wellbore multiphase flow law, cuttings carrying efficiency, and hydraulic fracturing technique during the drilling and completion process have become the key points. To accomplish related researches, a high-pressure water jet multi-functional flow test system was designed. The following novel researches are carried out: study of high-pressure water jet characteristics under confining pressure, wellbore multiphase flow regime, hydraulic pressure properties of down hole tools during jet fracturing and pulsed cavitation jet drilling, and deflector's friction in radial jet drilling. The validity and feasibility of the experimental results provided by the system with various test modules have proved its importance in the research of the high-pressure water jet and well completion technology.

  18. Further studies of the photoproduction of isolated photons with a jet at HERA

    NASA Astrophysics Data System (ADS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Arslan, O.; Aushev, V.; Aushev, Y.; Bachynska, O.; Barakbaev, A. N.; Bartosik, N.; Behnke, O.; Behr, J.; Behrens, U.; Bertolin, A.; Bhadra, S.; Bloch, I.; Bokhonov, V.; Boos, E. G.; Borras, K.; Brock, I.; Brugnera, R.; Bruni, A.; Brzozowska, B.; Bussey, P. J.; Caldwell, A.; Capua, M.; Catterall, C. D.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cooper-Sarkar, A. M.; Corradi, M.; Corriveau, F.; D'Agostini, G.; Dementiev, R. K.; Devenish, R. C. E.; Dolinska, G.; Drugakov, V.; Dusini, S.; Ferrando, J.; Figiel, J.; Foster, B.; Gach, G.; Garfagnini, A.; Geiser, A.; Gizhko, A.; Gladilin, L. K.; Gogota, O.; Golubkov, Yu. A.; Grebenyuk, J.; Gregor, I.; Grzelak, G.; Gueta, O.; Guzik, M.; Hain, W.; Hartner, G.; Hochman, D.; Hori, R.; Ibrahim, Z. A.; Iga, Y.; Ishitsuka, M.; Iudin, A.; Januschek, F.; Kadenko, I.; Kananov, S.; Kanno, T.; Karshon, U.; Kaur, M.; Kaur, P.; Khein, L. A.; Kisielewska, D.; Klanner, R.; Klein, U.; Kondrashova, N.; Kononenko, O.; Korol, Ie.; Korzhavina, I. A.; Kotanski, A.; Kötz, U.; Kovalchuk, N.; Kowalski, H.; Kuprash, O.; Kuze, M.; Levchenko, B. B.; Levy, A.; Libov, V.; Limentani, S.; Lisovyi, M.; Lobodzinska, E.; Lohmann, W.; Löhr, B.; Lohrmann, E.; Longhin, A.; Lontkovskyi, D.; Lukina, O. Yu.; Maeda, J.; Makarenko, I.; Malka, J.; Martin, J. F.; Mergelmeyer, S.; Idris, F. Mohamad; Mujkic, K.; Myronenko, V.; Nagano, K.; Nigro, A.; Nobe, T.; Notz, D.; Nowak, R. J.; Olkiewicz, K.; Onishchuk, Yu.; Paul, E.; Perlanski, W.; Perrey, H.; Pokrovskiy, N. S.; Proskuryakov, A. S.; Przybycien, M.; Raval, A.; Roloff, P.; Rubinsky, I.; Ruspa, M.; Samojlov, V.; Saxon, D. H.; Schioppa, M.; Schmidke, W. B.; Schneekloth, U.; Schörner-Sadenius, T.; Schwartz, J.; Shcheglova, L. M.; Shevchenko, R.; Shkola, O.; Singh, I.; Skillicorn, I. O.; Slominski, W.; Sola, V.; Solano, A.; Spiridonov, A.; Stanco, L.; Stefaniuk, N.; Stern, A.; Stewart, T. P.; Stopa, P.; Sztuk-Dambietz, J.; Szuba, D.; Szuba, J.; Tassi, E.; Temiraliev, T.; Tokushuku, K.; Tomaszewska, J.; Trofymov, A.; Trusov, V.; Tsurugai, T.; Turcato, M.; Turkot, O.; Tymieniecka, T.; Verbytskyi, A.; Viazlo, O.; Walczak, R.; Abdullah, W. A. T. Wan; Wichmann, K.; Wing, M.; Wolf, G.; Yamada, S.; Yamazaki, Y.; Zakharchuk, N.; Żarnecki, A. F.; Zawiejski, L.; Zenaiev, O.; Zhautykov, B. O.; Zhmak, N.; Zotkin, D. S.

    2014-08-01

    In this extended analysis using the ZEUS detector at HERA, the photoproduction of isolated photons together with a jet is measured for different ranges of the fractional photon energy, x {/γ meas}, contributing to the photon-jet final state. Cross sections are evaluated in the photon transverse-energy and pseudorapidity ranges 6 < E {/T γ } < 15 GeV and -0 .7 < η γ < 0 .9, and for jet transverse-energy and pseudorapidity ranges 4 < E {/T jet} < 35 GeV and -1 .5 < η jet < 1 .8, for an integrated luminosity of 374 pb-1. The kinematic observables studied comprise the transverse energy and pseudorapidity of the photon and the jet, the azimuthal difference between them, the fraction of proton energy taking part in the interaction, and the difference between the pseudorapidities of the photon and the jet. Higher-order theoretical calculations are compared to the results.

  19. Uniformity optimization and dynamic studies of plasma jet array interaction in argon

    NASA Astrophysics Data System (ADS)

    Wang, Ruixue; Sun, Hao; Zhu, Weidong; Zhang, Cheng; Zhang, Shuai; Shao, Tao

    2017-09-01

    In this paper, the uniformity of a microsecond pulse driven argon plasma jet array is studied by optimizing experimental parameters, such as the ground electrode position d, gas flow rate, and pulse frequency. The results show that when d is less than 10 mm, there are always two plasma jets that cannot be ignited; while all jets are ignited with equal length at d = 12.5 mm. The plasma jet transition from laminar to turbulent at 6 l/min, presenting a "bead-like" structure. The jet length increases with the pulse repetition frequency and reaches a plateau at around 1.5 kHz. The ICCD images show that the plasma jets emerged preferably from the two quartz tubings located at the two ends of the linear array. The spatial-temporal resolved spectra show that the Ar emission (763.5 nm) and N2 emission (337.1 nm) at the end of the array (e.g., Jet #1) appeared earlier than that of the jet in the middle (e.g., Jet #2). On the contrary, the emission intensities of Ar in Jet #2 are higher than in Jet #1. This is due to the higher electric field and air diffusion at the plasma array boundary.

  20. Flow visualization study of the effect of injection hole geometry on an inclined jet in crossflow

    NASA Technical Reports Server (NTRS)

    Simon, Frederick F.; Ciancone, Michael L.

    1987-01-01

    A flow visualization was studied by using neutrally buoyant, helium-filled soap bubbles, to determine the effect of injection hole geometry on the trajectory of an air jet in a crossflow and to investigate the mechanisms involved in jet deflection. Experimental variables were the blowing rate, and the injection hole geometry cusp facing upstream (CUS), cusp facing downstream (CDS), round, swirl passage, and oblong. It is indicated that jet deflection is governed by both the pressure drag forces and the entrainment of free-stream fluid into the jet flow. For injection hole geometries with similar cross-sectional areas and similar mass flow rates, the jet configuration with the larger aspect ratio experienced a greater deflection. Entrainment arises from lateral shearing forces on the sides of the jet, which set up a dual vortex motion within the jet and thereby cause some of the main-stream fluid momentum to be swept into the jet flow. This additional momentum forces the jet nearer the surface. Of the jet configurations, the oblong, CDS, and CUS configurations exhibited the largest deflections. The results correlate well with film cooling effectiveness data, which suggests a need to determine the jet exit configuration of optimum aspect ratio to provide maximum film cooling effectiveness.

  1. Flow visualization study of the effect of injection hole geometry on an inclined jet in crossflow

    NASA Technical Reports Server (NTRS)

    Simon, F. F.; Ciancone, M. L.

    1985-01-01

    A flow visualization was studied by using neutrally buoyant, helium-filled soap bubbles, to determine the effect of injection hole geometry on the trajectory of an air jet in a crossflow and to investigate the mechanisms involved in jet deflection. Experimental variables were the blowing rate, and the injection hole geometry cusp facing upstream (CUS), cusp facing downstream (CDS), round, swirl passage, and oblong. It is indicated that jet deflection is governed by both the pressure drag forces and the entrainment of free-stream fluid into the jet flow. For injection hole geometries with similar cross-sectional areas and similar mass flow rates, the jet configuration with the larger aspect ratio experienced a greater deflection. Entrainment arises from lateral shearing forces on the sides of the jet, which set up a dual vortex motion within the jet and thereby cause some of the main-stream fluid momentum to be swept into the jet flow. This additional momentum forces the jet nearer the surface. Of the jet configurations, the oblong, CDS, and CUS configutations exhibited the largest deflections. The results correlate well with film cooling effectiveness data, which suggests a need to determine the jet exit configuration of optimum aspect ratio to provide maximum film cooling effectiveness.

  2. Flow visualization study of the effect of injection hole geometry on an inclined jet in crossflow

    NASA Technical Reports Server (NTRS)

    Simon, Frederick F.; Ciancone, Michael L.

    1987-01-01

    A flow visualization was studied by using neutrally buoyant, helium-filled soap bubbles, to determine the effect of injection hole geometry on the trajectory of an air jet in a crossflow and to investigate the mechanisms involved in jet deflection. Experimental variables were the blowing rate, and the injection hole geometry cusp facing upstream (CUS), cusp facing downstream (CDS), round, swirl passage, and oblong. It is indicated that jet deflection is governed by both the pressure drag forces and the entrainment of free-stream fluid into the jet flow. For injection hole geometries with similar cross-sectional areas and similar mass flow rates, the jet configuration with the larger aspect ratio experienced a greater deflection. Entrainment arises from lateral shearing forces on the sides of the jet, which set up a dual vortex motion within the jet and thereby cause some of the main-stream fluid momentum to be swept into the jet flow. This additional momentum forces the jet nearer the surface. Of the jet configurations, the oblong, CDS, and CUS configurations exhibited the largest deflections. The results correlate well with film cooling effectiveness data, which suggests a need to determine the jet exit configuration of optimum aspect ratio to provide maximum film cooling effectiveness.

  3. Flow visualization study of the effect of injection hole geometry on an inclined jet in crossflow

    NASA Astrophysics Data System (ADS)

    Simon, Frederick F.; Ciancone, Michael L.

    A flow visualization was studied by using neutrally buoyant, helium-filled soap bubbles, to determine the effect of injection hole geometry on the trajectory of an air jet in a crossflow and to investigate the mechanisms involved in jet deflection. Experimental variables were the blowing rate, and the injection hole geometry cusp facing upstream (CUS), cusp facing downstream (CDS), round, swirl passage, and oblong. It is indicated that jet deflection is governed by both the pressure drag forces and the entrainment of free-stream fluid into the jet flow. For injection hole geometries with similar cross-sectional areas and similar mass flow rates, the jet configuration with the larger aspect ratio experienced a greater deflection. Entrainment arises from lateral shearing forces on the sides of the jet, which set up a dual vortex motion within the jet and thereby cause some of the main-stream fluid momentum to be swept into the jet flow. This additional momentum forces the jet nearer the surface. Of the jet configurations, the oblong, CDS, and CUS configurations exhibited the largest deflections. The results correlate well with film cooling effectiveness data, which suggests a need to determine the jet exit configuration of optimum aspect ratio to provide maximum film cooling effectiveness.

  4. Flow visualization study of the effect of injection hole geometry on an inclined jet in crossflow

    NASA Astrophysics Data System (ADS)

    Simon, F. F.; Ciancone, M. L.

    A flow visualization was studied by using neutrally buoyant, helium-filled soap bubbles, to determine the effect of injection hole geometry on the trajectory of an air jet in a crossflow and to investigate the mechanisms involved in jet deflection. Experimental variables were the blowing rate, and the injection hole geometry cusp facing upstream (CUS), cusp facing downstream (CDS), round, swirl passage, and oblong. It is indicated that jet deflection is governed by both the pressure drag forces and the entrainment of free-stream fluid into the jet flow. For injection hole geometries with similar cross-sectional areas and similar mass flow rates, the jet configuration with the larger aspect ratio experienced a greater deflection. Entrainment arises from lateral shearing forces on the sides of the jet, which set up a dual vortex motion within the jet and thereby cause some of the main-stream fluid momentum to be swept into the jet flow. This additional momentum forces the jet nearer the surface. Of the jet configurations, the oblong, CDS, and CUS configutations exhibited the largest deflections. The results correlate well with film cooling effectiveness data, which suggests a need to determine the jet exit configuration of optimum aspect ratio to provide maximum film cooling effectiveness.

  5. 35 minute green flash observed at Little America on 16 October 1929: a retrospective study.

    PubMed

    Lock, James A

    2015-02-01

    On 16 October 1929 five members of the Byrd Expedition 1 observed an intermittent 35 min green flash at the Little America station (latitude -78.57°) in Antarctica. The flash was the result of strong atmospheric refraction, likely associated with a subcritical Novaya Zemlya mirage. This paper examines the constraints placed on the observation by the Earth-Sun orbital kinematics. It is found that the length of the observation cannot be explained solely by the slowness of the setting rate of the Sun, nor the time required just before the beginning of the Antarctic summer for the top of the Sun to set, reach its relative minimum position at the horizon, and then rise back up again. The observed length of the effect, however, is consistent with the Sun effectively setting twice and rising twice during the observation, with the first effective rising being the result of the observers climbing up the radio towers at the Little America station in order to keep the top of the Sun in view.

  6. Sensitized and heavy atom induced production of acenaphthylene triplet: A laser flash photolysis study

    SciTech Connect

    Samanta, A.; Fessenden, R.W. )

    1989-07-27

    The triplet state of acenaphthylene has been examined by nanosecond laser flash photolysis using sensitization and heavy atom perturbation techniques. Although acenaphthylene does not form any observable triplet upon direct flash excitation, a transient with microsecond lifetime ({lambda}{sub max} = 315 nm) is observable when a solution of the sample is excited by sensitizers (benzophenone, thioxanthone, benzil). This transient is ascribed to the triplet of acenaphthylene on the basis of its quenching behavior toward oxygen, ferrocene, azulene, and {beta}-carotene. Quantitative data concerning the triplet-triplet absorption and quenching constants are presented. The triplet energy is estimated to lie between 46 and 47 kcal/mol. The triplet can also be produced by direct excitation in solvents containing heavy atoms (ethyl bromide, ethyl iodide). The triplet yield is found to increase with an increase of the amount of the heavy atom containing solvent. No saturation limit is obtained. These facts together with the effect of heavy atoms on the T{sub 1} {yields} S{sub 0} process allow the differing behavior of ethyl bromide and ethyl iodide on the photodimerization process of acenaphthylene to be explained. Triplet-state parameters (extinction coefficient and triplet yield) have been estimated in these solvents by the energy-transfer technique and actinometry.

  7. Statistical Study of Chromospheric Anemone Jets Observed with Hinode/SOT

    NASA Astrophysics Data System (ADS)

    Nishizuka, N.; Nakamura, T.; Kawate, T.; Singh, K. A. P.; Shibata, K.

    2011-04-01

    The Solar Optical Telescope on board Hinode has revealed numerous tiny jets in all regions of the chromosphere outside of sunspots. A typical chromospheric anemone jet has a cusp-shaped structure and bright footpoint, similar to the shape of an X-ray anemone jet observed previously with the Soft X-ray Telescope on board Yohkoh. The similarity in the shapes of chromospheric and X-ray anemone jets suggests that chromospheric anemone jets are produced as a result of the magnetic reconnection between a small bipole (perhaps a tiny emerging flux) and a pre-existing uniform magnetic field in the lower chromosphere. We examine various chromospheric anemone jets in the solar active region near the solar limb and study the typical features (e.g., length, width, lifetime, and velocity) of the chromospheric anemone jets. Statistical studies show that chromospheric anemone jets have: (1) a typical length ~1.0-4.0 Mm, (2) a width ~100-400 km, (3) a lifetime ~100-500 s, and (4) a velocity ~5-20 km s-1. The velocity of the chromospheric anemone jets is comparable to the local Alfvén speed in the lower solar chromosphere (~10 km s-1). The histograms of chromospheric anemone jets near the limb and near the disk center show similar averages and shapes of distributions, suggesting that the characteristic behavior of chromospheric anemone jets is independent of whether they are observed on the disk or at the limb. The observed relationship between the velocity and length of chromospheric anemone jets shows that the jets do not follow ballistic motion but are more likely accelerated by some other mechanism. This is consistent with numerical simulations of chromospheric anemone jets.

  8. A Study of Jet Energy Measurement at CDF

    SciTech Connect

    Bocci, A.

    1998-07-01

    In this thesis we first reviewed how jets have been reconstructed by the CDF collaboration in many successful analyses. We recalled how important an improvement in jet energy resolution would be for the physics foreseen in Run IL For example, it was shown in the Te V33 report that a 30% improvement in resolution would make a large impact in a light Higgs signal significance. Problems in jet energy reconstruction can depend on different effects which we grouped in physics and detector effects. In this thesis these two effects were addressed separately. The impact of physics effects on jet energy resolution was limited by merging extra jets next to a leading jet. In order to further improve the detector energy resolution a new way of defining the jet energy was proposed. Information from the CTC and from the strip chambers were used to reconstruct the energy of single particles in the jet whenever possible. The new method, called ''classification method'', was tested on the photon +jet data sample. The results obtained are encouraging. It was shown how a clear improvement in jet energy resolution can be achieved.

  9. NUCLEAR FLASH TYPE STEAM GENERATOR

    DOEpatents

    Johns, F.L.; Gronemeyer, E.C.; Dusbabek, M.R.

    1962-09-01

    A nuclear steam generating apparatus is designed so that steam may be generated from water heated directly by the nuclear heat source. The apparatus comprises a pair of pressure vessels mounted one within the other, the inner vessel containing a nuclear reactor heat source in the lower portion thereof to which water is pumped. A series of small ports are disposed in the upper portion of the inner vessel for jetting heated water under pressure outwardly into the atmosphere within the interior of the outer vessel, at which time part of the jetted water flashes into steam. The invention eliminates the necessity of any intermediate heat transfer medium and components ordinarily required for handling that medium. (AEC)

  10. Measuring hot flash phenomenonology using ambulatory prospective digital diaries.

    PubMed

    Fisher, William I; Thurston, Rebecca C

    2016-11-01

    This study provides the description, protocol, and results from a novel prospective ambulatory digital hot flash phenomenon diary. This study included 152 midlife women with daily hot flashes who completed an ambulatory electronic hot flash diary continuously for the waking hours of three consecutive days. In this diary, women recorded their hot flashes and accompanying characteristics and associations as the hot flashes occurred. 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 face (78.9%), neck (74.7%), and chest (61.3%). Of all reported hot flashes, 32% occurred concurrently with prickly skin, 7% with anxiety, and 5% with nausea. A novel finding from the study was that 38% of hot flashes were accompanied by a premonitory aura. A prospective electronic digital hot flash diary allows for a more precise quantitation of hot flashes while overcoming many of the limitations of commonly used 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.

  11. Experimental Study on Abrasive Water Jet Machining of PZT Ceramic

    NASA Astrophysics Data System (ADS)

    Dhanawade, Ajit; Upadhyai, Ravi; Rouniyar, Arunkumar; Kumar, Shailendra

    2017-07-01

    This paper presents research work involved in abrasive water jet machining of PZT ceramic material. Process parameters namely stand-off distance, water pressure and traverse rate are considered in the present study. Response surface methodology approach is used to design the experiments. Relative significance of process parameters and their influence on kerf properties are identified on the basis of analysis of variance. It is found that water pressure and traverse rate are most significant parameters followed by stand-off distance. On the basis of experimental analysis, regression models are developed to predict kerf taper and depth of cut. The models are developed with respect to significant parameters, interaction and quadratic terms. It is found that model predictions are in congruence with experimental results. Multi-response optimization of process parameters is also performed using desirability approach in order to minimize kerf taper and maximize depth of cut. Kerf wall features of machined surfaces are observed using scanning electron microscope. The findings of present study are useful to improve kerf properties in abrasive water jet machining of PZT ceramic materials.

  12. A Study on Multi-Jets Final States at the Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Amouzegar, Maya; Halkiadakis, Eva; Lath, Amitabh; Thomas, Scott; Gershtein, Yuri; CMS Collaboration

    2016-03-01

    The LHC (Large Hadron Collider) at CERN, located in Geneva, Switzerland, collides protons at a center of mass energy of 13 TeV. The CMS (Compact Muon Solenoid) detector is one of the four experiments that detects collisions at the LHC. One of the new physics phenomenon that is looked for by the CMS detector is Supersymmetry (SUSY). In our method, we look for these particles by looking at multi-jets final states in interactions that produce up to 8 jets in their final states. By comparing jets in new physics signals with ones produced through QCD, we would be able to predict where new physics might be lying. Since the standard model interactions mostly produce di-jets, if there is an excess of jets at a certain energy, it is possible that a process beyond the standard model is producing those jets. Most of the simulated Monte Carlo signals considered are R-Parity Violating SUSY interactions. In order to perform these studies, we studied the jets' transverse momentum (Pt) divided by the total hadronic energy in the event (HT) as a function of the jet multiplicity, between 2 and 8 jets. If there is an excess of transverse momentum, there is the possibility that SUSY particles are created and are decaying into jets. The studies performed here were a result of the National Science Foundation Research Experiences for Undergraduates (REU) program, and has been supported by funding from NSF Grant PHY-1263280.

  13. A study of multi-jet production ratios in p{anti p} collisions at D0

    SciTech Connect

    Gallas, E.; D0 Collaboration

    1996-09-01

    The authors study inclusive jet multiplicity ratios in multi-jet events from p{anti p} collisions at {radical}s = 1.8 TeV recorded using the D0 detector at the Fermilab Tevatron collider. Preliminary average multi-jet production ratios are presented as a function of the scalar jet transverse energy and compared to NLO calculations.

  14. Susceptibility to the Flash-Beep Illusion Is Increased in Children Compared to Adults

    ERIC Educational Resources Information Center

    Innes-Brown, Hamish; Barutchu, Ayla; Shivdasani, Mohit N.; Crewther, David P.; Grayden, David B.; Paolini, Antonio

    2011-01-01

    Audio-visual integration was studied in children aged 8-17 (N = 30) and adults (N = 22) using the "flash-beep illusion" paradigm, where the presentation of two beeps causes a single flash to be perceived as two flashes ("fission" illusion), and a single beep causes two flashes to be perceived as one flash ("fusion" illusion). Children reported…

  15. Susceptibility to the Flash-Beep Illusion Is Increased in Children Compared to Adults

    ERIC Educational Resources Information Center

    Innes-Brown, Hamish; Barutchu, Ayla; Shivdasani, Mohit N.; Crewther, David P.; Grayden, David B.; Paolini, Antonio

    2011-01-01

    Audio-visual integration was studied in children aged 8-17 (N = 30) and adults (N = 22) using the "flash-beep illusion" paradigm, where the presentation of two beeps causes a single flash to be perceived as two flashes ("fission" illusion), and a single beep causes two flashes to be perceived as one flash ("fusion" illusion). Children reported…

  16. A computational study of highly viscous impinging jets

    SciTech Connect

    Silva, M.W.

    1998-11-01

    Two commercially-available computational fluid dynamics codes, FIDAP (Fluent, Inc., Lebanon, NH) and FLOW-3D (Flow Science, Inc., Los Alamos, NM), were used to simulate the landing region of jets of highly viscous fluids impinging on flat surfaces. The volume-of-fluid method was combined with finite difference and finite element approaches to predict the jet behavior. Several computational models with varying degrees of physical realism were developed, and the results were compared with experimental observations. In experiments, the jet exhibited several complex behaviors. As soon as it exited the nozzle, the jet began to neck down and become narrower. When it impacted the solid surface, the jet developed an instability near the impact point and buckled to the side. This buckling became a spiraling motion, and the jet spiraled about the impact point. As the jet spiraled around, a cone-shaped pile was build up which eventually became unstable and slumped to the side. While all of these behaviors were occurring, air bubbles, or voids, were being entrapped in the fluid pool. The results obtained from the FLOW-3D models more closely matched the behavior of real jets than the results obtained from /the FIDAP models. Most of the FLOW-3D models predicted all of the significant jet behaviors observed in experiments: necking, buckling, spiraling, slumping, and void entrapment. All of the FIDAP models predicted that the jet would buckle relatively far from the point of impact, whereas the experimentally observed jet behavior indicates that the jets buckle much nearer the impact point. Furthermore, it was shown that FIDAP is incapable of incorporating heat transfer effects into the model, making it unsuitable for this work.

  17. General relativistic study of astrophysical jets with internal shocks

    NASA Astrophysics Data System (ADS)

    Vyas, Mukesh K.; Chattopadhyay, Indranil

    2017-08-01

    We explore the possibility of the formation of steady internal shocks in jets around black holes. We consider a fluid described by a relativistic equation of state, flowing about the axis of symmetry (θ = 0) in a Schwarzschild metric. We use two models for the jet geometry: (i) a conical geometry and (ii) a geometry with non-conical cross-section. A jet with conical geometry has a smooth flow, while the jet with non-conical cross-section undergoes multiple sonic points and even standing shock. The jet shock becomes stronger, as the shock location is situated farther from the central black hole. Jets with very high energy and very low energy do not harbour shocks, but jets with intermediate energies do harbour shocks. One advantage of these shocks, as opposed to shocks mediated by external medium, is that these shocks have no effect on the jet terminal speed, but may act as possible sites for particle acceleration. Typically, a jet with specific energy 1.8c2 will achieve a terminal speed of v∞ = 0.813c for jet with any geometry, where, c is the speed of light in vacuum. But for a jet of non-conical cross-section for which the length scale of the inner torus of the accretion disc is 40rg, then, in addition, a steady shock will form at rsh ∼ 7.5rg and compression ratio of R ∼ 2.7. Moreover, electron-proton jet seems to harbour the strongest shock. We will discuss possible consequences of such a scenario.

  18. An empirical study of the effect of the variables in a flash vacuum pyrolysis (FVP) experiment.

    PubMed

    Duffy, Emma F; Foot, Jonathan S; McNab, Hamish; Milligan, Andrew A

    2004-09-21

    The effect of the variation of the experimental parameters on the conversion of precursor to products in a typical flash vacuum pyrolysis (FVP) experiment was investigated empirically. Temperature-conversion plots can be used to optimise FVP conditions and their mechanistic significance is exemplified. At a given temperature, the conversion can be increased by an increase in the background pressure, or by packing a section of the furnace tube with inert material (particularly when placed at the trap end of the furnace tube) or by employing a catalyst. Despite the prevailing view that only intramolecular reactions take place by FVP, it has been shown by a 'dual-FVP' cross-over experiment that the dimerisation of benzyl radicals occurs in the gas-phase, before the cold trap, under standard conditions. However, reduction in through-put rate, increase in furnace temperature and reduction in background pressure all reduce the amount of gas-phase coupling.

  19. Polyelectrolyte stabilized drug nanoparticles via flash nanoprecipitation: a model study with beta-carotene.

    PubMed

    Zhu, Zhengxi; Margulis-Goshen, Katrin; Magdassi, Shlomo; Talmon, Yeshayahu; Macosko, Christopher W

    2010-10-01

    Polyelectrolyte protected beta-carotene nanoparticles (nanosuspensions) with average diameter of <100 nm were achieved by turbulent mixing and flash nanoprecipitation (FNP). Three types of multi-amine functional polyelectrolytes, epsilon-polylysine (epsilon-PL), poly(ethylene imine) (PEI), and chitosan, were investigated to electrosterically protect the nanoparticles. Particle size and distribution were measured by dynamic light scattering (DLS); particles were imaged via scanning electron microscopy (SEM) and cryogenic transmission electron microscopy (cryo-TEM). Low pH and high polyelectrolyte molecular weight gave the smallest and most stable particles. High drug loading capacity, >80 wt%, was achieved by using either PEI or chitosan. X-ray diffraction (XRD) patterns showed that beta-carotene nanoparticles were amorphous. These findings open the way for utilization of FNP for preparation of nanoparticles with enhanced bioavailability for highly water insoluble drugs.

  20. Resolution Studies at Beam Position Monitors at the FLASH Facility at DESY

    SciTech Connect

    Baboi, N.; Lund-Nielsen, J.; Noelle, D.; Traber, T.; Kruse, J.; Riesch, W.; Wendt, M.

    2006-11-20

    More than 60 beam position monitors (BPM) are installed along about 350m of beamline of the Free Electron LASer in Hamburg (FLASH) at DESY. The room-temperature part of the accelerator is equipped mainly with stripline position monitors. In the accelerating cryo-modules there are cavity and re-entrant cavity BPMs, which will not be discussed here. In the undulator part of the machine button BPMs are used. This area requires a single bunch resolution of 10{mu}m. The electronics is based on the AM/PM normalization principle and is externally triggered. Single-bunch position is measured. This paper presents the methods used to determine the resolution of the BPMs. The results based on correlations between different BPMs along the machine are compared to noise measurements in the RF lab. The performance and difficulties with the BPM design and the current electronics as well as its development are discussed.

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

    NASA Astrophysics Data System (ADS)

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

    2009-09-01

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

  2. An Experimental Study of Synthetic Jets from Rectangular Orifices

    NASA Technical Reports Server (NTRS)

    Milanovic, Ivana M.

    2003-01-01

    During the past two summers Professor Milanovic conducted Wind tunnel experiments on steady jets-in-cross-flow and synthetic jets. In her anticipated visit during the upcoming summer, she will continue and complete the research on synthetic jets involving 2-dimensional orifices of different aspect ratio as well as inclined slots. In addition, experiments will be conducted on pulsatile jets-in-cross-flow. The pulsation will be provided via an oscillating valve at controllable frequencies. The experiment will involve mainly hot-wire anemometer measurements in the low-speed wind tunnel. Overall goal will be to obtain database and investigate flow control strategies. The research will be of fundamental nature.

  3. Multi-frequency study of jet in HH 80-81

    NASA Astrophysics Data System (ADS)

    Pal, Sabyasachi; Chakrabarti, Sandip Kumar; Patra, Dusmanta

    2016-07-01

    We present multi-wavelength radio observation of the large radio jet from Herbig-Halo object HH 80-81 to study morphology of the jet in detail. We have combined the low frequency data of Giant Metrewave Radio Telescope (GMRT) with high frequency Jansky Very Large Array (JVLA) archival data for multi-frequency study. We have seen a highly collimated jet emitting from central source and the jet is collinear with the central source and HH 80-81. The spectrum of the source is studied in detail and we find the signature of spectral absorption towards the low frequency region.

  4. Molecular jets driven by high-mass protostars: a detailed study of the IRAS 20126+4104 jet

    NASA Astrophysics Data System (ADS)

    Caratti o Garatti, A.; Froebrich, D.; Eislöffel, J.; Giannini, T.; Nisini, B.

    2008-07-01

    Context: Protostellar jets from intermediate- and high-mass protostars provide an excellent opportunity to understand the mechanisms responsible for intermediate- and high-mass star-formation. A crucial question is if they are scaled-up versions of their low-mass counterparts. Such high-mass jets are relatively rare and, usually, they are distant and highly embedded in their parental clouds. The IRAS 20126+4104 molecular jet, driven by a 10^4 L⊙ protostar, represents a suitable target to investigate. Aims: We present here an extensive analysis of this protostellar jet, deriving the kinematical, dynamical, and physical conditions of the H2 gas along the flow. Methods: The jet was investigated by means of near-IR H2 and [Fe II] narrow-band imaging, high-resolution spectroscopy of the 1-0 S(1) line (2.12 μm), NIR (0.9-2.5 μm) low-resolution spectroscopy, along with ISO-SWS and LWS spectra (from 2.4 to 200 μm). Results: The flow shows a complex morphology. In addition to the large-scale jet precession presented in previous studies, we detect a small-scale wiggling close to the source, which may indicate the presence of a multiple system. The peak radial velocities of the H2 knots range from -42 to -14 km s-1 in the blue lobe, and from -8 to 47 km s-1 in the red lobe. The low-resolution spectra are rich in H2 emission, and relatively faint [Fe II] (NIR), [O I] and [C II] (FIR) emission is observed in the region close to the source. A warm H2 gas component has an average excitation temperature that ranges between 2000 K and 2500 K. Additionally, the ISO-SWS spectrum reveals a cold component (520 K) that strongly contributes to the radiative cooling of the flow and plays a major role in the dynamics of the flow. The estimated L_H2 of the jet is 8.2 ± 0.7 L⊙, suggesting that IRAS 20126+4104 has a significantly increased accretion rate compared to low-mass YSOs. This is also supported by the derived mass flux rate from the H2 lines (dot{M}_out(H2)˜ 7.5× 10-4 M

  5. Parametric Study of Synthetic-Jet-Based Flow Control on a Vertical Tail Model

    NASA Astrophysics Data System (ADS)

    Monastero, Marianne; Lindstrom, Annika; Beyar, Michael; Amitay, Michael

    2015-11-01

    Separation control over the rudder of the vertical tail of a commercial airplane using synthetic-jet-based flow control can lead to a reduction in tail size, with an associated decrease in drag and increase in fuel savings. A parametric, experimental study was undertaken using an array of finite span synthetic jets to investigate the sensitivity of the enhanced vertical tail side force to jet parameters, such as jet spanwise spacing and jet momentum coefficient. A generic wind tunnel model was designed and fabricated to fundamentally study the effects of the jet parameters at varying rudder deflection and model sideslip angles. Wind tunnel results obtained from pressure measurements and tuft flow visualization in the Rensselaer Polytechnic Subsonic Wind Tunnel show a decrease in separation severity and increase in model performance in comparison to the baseline, non-actuated case. The sensitivity to various parameters will be presented.

  6. Study of Air Entrainment by a Horizontal Plunging Liquid Jet

    NASA Astrophysics Data System (ADS)

    Trujillo, Mario; Deshpande, Suraj; Wu, Xiongjun; Chahine, Georges

    2009-11-01

    The process of air entrainment following the impact of an initially horizontal circular water jet on a pool of water has been studied computationally and experimentally. It has been found that the entrainment of air cavities in the near field region is periodic, not continuous as reported in earlier studies. The simulations are based on a Volume-of-Fluid methodology with interfacial compression using a modified version of the open source utilities, OpenFoam. Close agreement with experiments is reported on the creation of cavities in the near field, where air entrainment occurs. The period of entrainment is found to be proportional to g, and a simplified closed-form solution for this periodic event is presented. An overall physical picture of the mechanisms leading to bubble formation is given. The far field, which is characterized by the presence of small bubbles is only partially resolved computationally. Comparisons against velocity data are performed in this region leading to adequate qualitative agreement.

  7. Shock Tube/Laser Absorption Studies of Jet Fuels at Low Temperatures (600-1200K)

    DTIC Science & Technology

    2013-08-27

    temperatures: the development of a fundamental kinetics database utilizing shock tubes and laser absorption for jet fuel surrogate components; the...combustion of jet fuels at low temperatures: the development of a fundamental kinetics database utilizing shock tubes and laser absorption for jet fuel...Davidson, Ronald Hanson. IR Laser Absorption DIagnostic for C2H4 in Shock Tube Kinetics Studies, International Journal of Chemical Kinetics , (07 2012): 423

  8. Arc Jet Testing of Thermal Protection Materials: 3 Case Studies

    NASA Technical Reports Server (NTRS)

    Johnson, Sylvia; Conley, Joe

    2015-01-01

    Arc jet testing is used to simulate entry to test thermal protection materials. This paper discusses the usefulness of arc jet testing for 3 cases. Case 1 is MSL and PICA, Case 2 is Advanced TUFROC, and Case 3 is conformable ablators.

  9. Changes of flash droughts over China

    NASA Astrophysics Data System (ADS)

    Wang, Linying; Yuan, Xing

    2016-04-01

    The rapidly evolving drought events, which are recently termed as "flash droughts", can seriously affect vegetation and water supply due to extreme heat, low soil moisture and high evapotranspiration (ET). The changes of flash droughts are not only caused by natural climate variability similar to the traditional drought events, but also associated with global warming since abnormally high temperature is an important criterion for the triggering of flash droughts. Here, we have assessed the long-term trend and variability of flash droughts over China from 1979 to 2010, based on over two thousand meteorological observations of surface air temperature and three global reanalysis products for the soil moisture and ET estimations. Our results suggest that the flash droughts are most likely to occur in humid and semihumid regions, such as southern and northeastern China. Basically, there are increasing trends for flash droughts over different regions in China mainly due to the temperature increases. The increasing trends of flash droughts do not decline during the second half of the study period, but the warming hiatus does exist over many regions of China. The underlying mechanisms are being attributed by investigating the changes in temperature, soil moisture and ET over different parts of China. This study uniquely demonstrates the favorable regions for the occurrence of flash droughts over China, and is targeted at attributing the changes of flash droughts within the context of the understanding of the terrestrial water and energy cycle in a changing climate.

  10. An experimental study of turbulent flow in attachment jet combustors by LDV

    NASA Astrophysics Data System (ADS)

    Li, Jun; Wu, Cheng-Kang

    1993-12-01

    Flame stabilization in attachment jet combustors is based on the existence of the high temperature recirculation zone, provided by the Coanda effect of an attachment jet. The single attachment jet in a rectangular channel is a fundamental form of this type of flow. In this paper, the detailed characteristics of turbulent flow of a single attachment jet were experimentally studied by using a 2-D LDV. The flowfield consists of a forward flow and two reverse flows. The forward one is composed of a curved and a straight section. The curved section resembles a bent turbulent free jet, and the straight part is basically a section of turbulent wall jet. A turbulent counter-gradient transport region exists at the curved section. According to the results, this kind of combustor should have a large sudden enlargement ratio and not too narrow in width.

  11. Electronic Flash In Data Acquisition

    NASA Astrophysics Data System (ADS)

    Miller, C. E.

    1982-02-01

    Photographic acquisition of data often may be simplified, or the data quality improved upon by employing electronic flash sources with traditional equipment or techniques. The relatively short flash duration compared to movie camera shutters, or to the long integration time of video camera provides improved spatial resolution through blur reduction, particularly important as image movement becomes a significant fraction of film format dimension. Greater accuracy typically is achieved in velocity and acceleration determinations by using a stroboscopic light source rather than a movie camera frame-rate control as a time standard. Electrical efficiency often is an important advantage of electronic flash sources since almost any necessary light level for exposure may be produced, yet the source typically is "off" most of the time. Various synchronization techniques greatly expand the precise control of exposure. Biomechanical and sports equipment studies may involve velocities up to 200 feet-per-second, and often will have associated very rapid actions of interest. The need for brief exposures increases H.s one "ZOOMS in on the action." In golf, for example, the swing may be examined using 100 microsecond (Us) flashes at rates of 60 or 120 flashes-per-second (FPS). Accurate determination of linear and rotational velocity of the ball requires 10 Us flashes at 500-1,000 FPS, while sub-Us flashes at 20,000-50,000 FPS are required to resolve the interaction of the ball and the club, head. Some seldom. used techniques involving streak photography are described, with enhanced results obtained by combining strobe with the usual continuous light source. The combination of strobe and a fast electro-mechanical shutter is considered for Us photography under daylight conditions.

  12. Anethole-Water a Combined Jet, Matrix, and Computational Study

    NASA Astrophysics Data System (ADS)

    Newby, Josh; Nesheiwat, Jackleen

    2016-06-01

    Anethole [(E)-1-methoxy-4-(1-propenyl)benzene] is a natural product molecule that is commonly recognized as the flavor component of anise, fennel, and licorice. Previously, we reported the jet-cooled, laser-induced fluorescence (LIF) and single vibronic level fluorescence (SVLF) spectra of anethole. In this work, several weak bands were observed and were tentatively assigned as van der Waals clusters of anethole with water. We have since confirmed this assignment and have conducted a more detailed study to determine the geometry of these clusters. Results from LIF, SVLF, and matrix isolation FTIR spectroscopy, as well as computational results will be presented in this talk. J. Phys. Chem. A, 2013, 117 (48), 12831-12841 Newly built system at Hobart and William Smith Colleges

  13. Thunderstorm Charge Structures Producing Negative Gigantic Jets

    NASA Astrophysics Data System (ADS)

    Boggs, L.; Liu, N.; Riousset, J. A.; Shi, F.; Rassoul, H.

    2016-12-01

    Here we present observational and modeling results that provide insight into thunderstorm charge structures that produce gigantic jet discharges. The observational results include data from four different thunderstorms producing 9 negative gigantic jets from 2010 to 2014. We used radar, very high frequency (VHF) and low frequency (LF) lightning data to analyze the storm characteristics, charge structures, and lightning activity when the gigantic jets emerged from the parent thunderstorms. A detailed investigation of the evolution of one of the charge structures by analyzing the VHF data is also presented. The newly found charge structure obtained from the observations was analyzed with fractal modeling and compared with previous fractal modeling studies [Krehbiel et al., Nat. Geosci., 1, 233-237, 2008; Riousset et al., JGR, 115, A00E10, 2010] of gigantic jet discharges. Our work finds that for normal polarity thunderstorms, gigantic jet charge structures feature a narrow upper positive charge region over a wide middle negative charge region. There also likely exists a `ring' of negative screening charge located around the perimeter of the upper positive charge. This is different from previously thought charge structures of the storms producing gigantic jets, which had a very wide upper positive charge region over a wide middle negative charge region, with a very small negative screening layer covering the cloud top. The newly found charge structure results in leader discharge trees in the fractal simulations that closely match the parent flashes of gigantic jets inside and outside the thundercloud. The previously used charge structures, while vital to the understanding of gigantic jet initiation and the role of charge imbalances inside the cloud, do not produce leader discharge trees that agree with observed gigantic jet discharges.Finally, the newly discovered gigantic jet charge structures are formed near the end of a convective pulse [Meyer et al., JGR, 118

  14. Theoretical study of the effects of refraction on the noise produced by turbulence in jets

    NASA Technical Reports Server (NTRS)

    Graham, E. W.; Graham, B. B.

    1974-01-01

    The production of noise by turbulence in jets is an extremely complex problem. One aspect of that problem, the transmission of acoustic disturbances from the interior of the jet through the mean velocity profile and into the far field is studied. The jet (two-dimensional or circular cylindrical) is assumed infinitely long with mean velocity profile independent of streamwise location. The noise generator is a sequence of transient sources drifting with the surrounding fluid and confined to a short length of the jet.

  15. Estimation of flash floods in small ungauged basins in Slovakia: case studies

    NASA Astrophysics Data System (ADS)

    Hlavcova, Kamila; Horvat, Oliver; Kohnova, Silvia; Szolgay, Jan; Roncak, Peter

    2013-04-01

    In the paper application of a methodology for analysis of flash flood events in several ungauged small basins in Slovakia was evaluated. The methodology proposed within the framework of the FP6 HYDRATE project (www.hydrate.tesaf.unipd.it) is based on the post-event surveying and hydrological modelling, using a spatially distributed hydrological model with a high spatial resolution of rainfall data and physiographical basin properties. Six large flash floods which occurred in Slovakia during the last 10 years were selected, with the emphasis on their extremity and different physical and geographical basins properties. The estimation of the maximum flood peaks and flood wave volumes was provided on the base of the post-event analysis after the flood events. The areas of channel's cross-profiles were measured for maximal water level, longitudinal slope of water level was approximated to the bottom slope and roughness was estimated according to the river banks and channel bottoms. Flow velocities were estimated using Chézy equation and Manning roughness coefficient. The reconstructed flood waves were compared with the simulated discharges using the distributed event-based rainfall-runoff model KLEM. The distributed hydrological model KLEM is based on the availability of raster information of the landscape's topography, soil and vegetation properties, and radar rainfall data. The SCS-Curve Number procedure is applied on a grid for the spatially-distributed representation of runoff-generating processes, a description of the drainage system response is used for representing the runoff's routing. Digital elevation models as well as soil, geology, land use and rainfall data for the basins were prepared in the grid form (resolution of 20 m). Radar rainfall data or maps of isohyets in 15-minutes time step or were used as input precipitation in the model. Comparison of the results achieved by the KLEM model and the post-event analysis for floods showed the consistency of

  16. What quenches the helium shell flashes. [thermonuclear reactions in stars

    NASA Technical Reports Server (NTRS)

    Sackmann, I.-J.

    1977-01-01

    An analysis is conducted of a typical stellar helium shell flash cycle. A sequence of 12 flashes for a population I star is considered. The changes taking place at a constant mass layer in the helium-burning shell are studied as the flash develops. A highly simplified mathematical description is presented, taking into account the three necessary conditions for the occurrence of the flash and the pressure-density and temperature-density relationships. Quantities which are helpful in explaining what triggers the flash are found to be useful in explaining what quenches the flash.

  17. Numerical study of a confined slot impinging jet with nanofluids

    PubMed Central

    2011-01-01

    Background Heat transfer enhancement technology concerns with the aim of developing more efficient systems to satisfy the increasing demands of many applications in the fields of automotive, aerospace, electronic and process industry. A solution for obtaining efficient cooling systems is represented by the use of confined or unconfined impinging jets. Moreover, the possibility of increasing the thermal performances of the working fluids can be taken into account, and the introduction of nanoparticles in a base fluid can be considered. Results In this article, a numerical investigation on confined impinging slot jet working with a mixture of water and Al2O3 nanoparticles is described. The flow is turbulent and a constant temperature is applied on the impinging. A single-phase model approach has been adopted. Different geometric ratios, particle volume concentrations and Reynolds number have been considered to study the behavior of the system in terms of average and local Nusselt number, convective heat transfer coefficient and required pumping power profiles, temperature fields and stream function contours. Conclusions The dimensionless stream function contours show that the intensity and size of the vortex structures depend on the confining effects, given by H/W ratio, Reynolds number and particle concentrations. Furthermore, for increasing concentrations, nanofluids realize increasing fluid bulk temperature, as a result of the elevated thermal conductivity of mixtures. The local Nusselt number profiles show the highest values at the stagnation point, and the lowest at the end of the heated plate. The average Nusselt number increases for increasing particle concentrations and Reynolds numbers; moreover, the highest values are observed for H/W = 10, and a maximum increase of 18% is detected at a concentration equal to 6%. The required pumping power as well as Reynolds number increases and particle concentrations grow, which is almost 4.8 times greater than the

  18. Bradycardia from flash stimulation.

    PubMed

    Einspenner, Michael; Brunet, Donald G; Boissé Lomax, Lysa; Spiller, Allison E

    2015-12-01

    This case study documents a patient who experienced bradycardia brought on by flash stimulation during a routine outpatient EEG recording. The patient had known photosensitive seizures in the past. During this routine EEG, the patient's heart rate dropped to about 12 beats per minute with the EEG displaying slow-delta-frequency waves with no epileptiform spikes or sharp waves. During immediate follow-up, in our emergency department, the patient had a brief asystolic event, followed by bradycardia. Cardiology examinations were normal. We propose that this response was a photic-triggered reflex vasovagal reaction.

  19. A laser flash photolysis and pulse radiolysis study of primary photochemical processes of flumequine.

    PubMed

    Bazin, M; Bosca, F; Marin, M L; Miranda, M A; Patterson, L K; Santus, R

    2000-10-01

    The 355 nm laser flash photolysis of argon-saturated pH 8 phosphate buffer solutions of the fluoroquinolone antibiotic flumequine produces a transient triplet state with a maximum absorbance at 575 nm where the molar absorptivity is 14,000 M(-1) cm(-1). The quantum yield of triplet formation is 0.9. The transient triplet state is quenched by various Type-1 photodynamic substrates such as tryptophan (TrpH), tyrosine, N-acetylcysteine and 2-deoxyguanosine leading to the formation of the semireduced flumequine species. This semireduced form has been readily identified by pulse radiolysis of argon-saturated pH 8 buffered aqueous solutions by reaction of the hydrated electrons and the CO2*- radicals with flumequine. The absorption maximum of the transient semireduced species is found at 570 nm with a molar absorptivity of 2,500 M(-1) cm(-1). In argon-saturated buffered solutions, the semireduced flumequine species formed by the reaction of the flumequine triplet with TrpH stoichiometrically reduces ferricytochrome C (Cyt Fe3+) under steady state irradiation with ultraviolet-A light. In the presence of oxygen, O2*- is formed but the photoreduction of Cyt Fe3+ by O2*- competes with an oxidizing pathway which involves photo-oxidation products of TrpH.

  20. A Study of Flash Anneal in combination with the conventional RTA for DRAM application

    NASA Astrophysics Data System (ADS)

    Lee, YoungHo; Lee, JinKu; Lee, MiRi; Jeon, SeungJoon; Oh, JaeGeun; Lee, Yu. Jun; Shin, MinJung; Kim, JaeYoung; Cha, SeonYong; Hong, Kwon; Park, SungKi; Kusuda, Tatsufumi; Nishihara, Hideo; Yokouchi, Kenichi

    2011-01-01

    We have investigated the effects of FLA technique on the DRAM peripheral transistor improvements by integrating into the SDRTA (Source/Drain RTA) and ADD RTA (Add RTA after contact formation). FLA with conventional RTA was not effective because of SCE (Short Channel Effect) control. FLA only was effective to improve SCE and Iop, and especially more effective on technology shrink. By flash anneal (FLA), we tried to achieve better activation, lower series resistance and less dopant loss. For higher activation, the pre-heat temperature of FLA was varied by 50 °C higher or lower than the desired base temperature. For lower resistance, the sidewall spacer thickness was reduced by 50 Å, 100 Å and 150 Å. For reducing dopant loss during the contact etch process, the deeper S/D Rp was used by increasing the S/D implant energy with an increased Rp by 150 Å, 200 Å and 250 Å. Results with FLA base show 13.4% improvement, and at the higher pre-heat temperature, it can be improved to 16.9%. In conclusion, FLA can be one of the candidates for periperal transistor performance improvement of next generation DRAM device.

  1. Fluid loading in abdominal surgery - saline versus hydroxyethyl starch (FLASH Trial): study protocol for a randomized controlled trial.

    PubMed

    Futier, Emmanuel; Biais, Matthieu; Godet, Thomas; Bernard, Lise; Rolhion, Christine; Bourdier, Justine; Morand, Dominique; Pereira, Bruno; Jaber, Samir

    2015-12-21

    Inappropriate fluid therapy during surgery is associated with significant morbidity and mortality. Few studies have examined the effects of particular types of fluids (crystalloid or colloid solutions) in surgical patients, especially with the goal of hemodynamic optimization. Isotonic saline is the most commonly used fluid worldwide but may be associated with potential nephrotoxicity. Hydroxyethyl starch (HES) solutions are widely used in surgical patients as a component of goal-directed fluid optimization strategies, but several large multicenter studies have suggested increased rates of acute kidney injury and adverse events with the use of HES in ICU patients. Despite what may be inferred from physiological studies, the benefit and harm of 0.9 % saline and HES during hemodynamic therapy have not been clearly established in surgical patients. The FLASH trial is an investigator-initiated, prospective, multicenter, randomized, double-blinded, two-arm trial, randomizing 826 patients with moderate-to-high risk of postoperative complications to receive 6 % HES 130/0.4 or 0.9 % saline during individualized goal-directed fluid optimization. The primary outcome measure is a composite of death or major postoperative complications within 14 days following surgery. The sample size will allow the detection of a 10 % absolute between-group difference in the primary outcome measure with a type 1 error rate of 5 % and power of 95 %, assuming a 5 % mortality rate and 20 % morbidity (thus 25 % for the composite endpoint). The FLASH trial may provide important data on the efficacy and safety of commonly used fluid solutions and could have a significant impact on future treatment of surgical patients. ClinicalTrials.gov Identifier: NCT02502773 . Registered 16 June 2015.

  2. Seeking the mechanism responsible for fluoroquinolone photomutagenicity: a pulse radiolysis, steady-state, and laser flash photolysis study.

    PubMed

    Soldevila, Sonia; Consuelo Cuquerella, M; Lhiaubet-Vallet, Virginie; Edge, Ruth; Bosca, Francisco

    2014-02-01

    The mechanism responsible for the remarkable photomutagenicity of fluoroquinolone (FQ) antibiotics remains unknown. For this reason, it was considered worthwhile to study in detail the interactions between DNA and a dihalogenated FQ such as lomefloxacin (LFX; one of the most photomutagenic FQs) and its N-acetyl derivative ALFX. Studies of photosensitized DNA damage by (A)LFX, such as formation of DNA single-strand breaks (SSBs), together with pulse radiolysis, laser flash photolysis, and absorption and fluorescence measurements, have shown the important effects of the cationic character of the piperazinyl ring on the affinity of this type of drug for DNA. Hence, the formation of SSBs was detected for LFX, whereas ALFX and ciprofloxacin (a monofluorated FQ) needed a considerably larger dose of light to produce some damage. In this context, it was determined that the association constant (Ka) for the binding of LFX to DNA is ca. 2×10(3)M(-1), whereas in the case of ALFX it is only ca. 0.5×10(3)M(-1). This important difference is attributed to an association between the cationic peripheral ring of LFX and the phosphate moieties of DNA and justifies the DNA SSB results. The analysis of the transient species detected and the photomixtures has allowed us to establish the intermolecular processes involved in the photolysis of FQ in the presence of DNA and 2'-deoxyguanosine (dGuo). Interestingly, although a covalent binding of the dihalogenated FQ to dGuo occurs, the photodegradation of FQ…DNA complexes did not reveal any significant covalent attachment. Another remarkable outcome of this study was that (A)LFX radical anions, intermediates required for the onset of DNA damage, were detected by pulse radiolysis but not by laser flash photolysis. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Study of instability of liquid jets under gravity

    NASA Astrophysics Data System (ADS)

    Bani, Wellstandfree K.; Mahato, Mangal C.

    2017-05-01

    Breakup of water jets under gravity is a common-place phenomenon. The role of surface tension in the instability of water jets was recognized by Rayleigh and the theory propounded goes by the name of Plateau-Rayleigh theory. The necks and bulges down along the jet-length that are created by perturbation waves of wavelengths larger than a certain value keep growing with time and ultimately cause the jet to breakup into drops. The effect of perturbation waves have been investigated and found to confirm the essentials of the theory. However, there is no unanimity about the origin of these perturbation waves. Recently, the idea of recoil capillary waves as an important source of the perturbation waves has been emphasized. The recoil of the end point of the jet at its breakup point is considered to travel upward as a recoil capillary wave which gets reflected at the mouth of the nozzle from which the jet originates. The reflected capillary wave travels along the jet downward with its Doppler shifted wavelength as a perturbation wave. We set up an experiment to directly verify the existence and effect of the recoil capillary waves and present some preliminary results of our experiment.

  4. A STUDY OF RADIO POLARIZATION IN PROTOSTELLAR JETS

    SciTech Connect

    Cécere, Mariana; Velázquez, Pablo F.; De Colle, Fabio; Esquivel, Alejandro; Araudo, Anabella T.; Carrasco-González, Carlos; Rodríguez, Luis F.

    2016-01-10

    Synchrotron radiation is commonly observed in connection with shocks of different velocities, ranging from relativistic shocks associated with active galactic nuclei, gamma-ray bursts, or microquasars, to weakly or non-relativistic flows such as those observed in supernova remnants. Recent observations of synchrotron emission in protostellar jets are important not only because they extend the range over which the acceleration process works, but also because they allow us to determine the jet and/or interstellar magnetic field structure, thus giving insights into the jet ejection and collimation mechanisms. In this paper, we compute for the first time polarized (synchrotron) and non-polarized (thermal X-ray) synthetic emission maps from axisymmetrical simulations of magnetized protostellar jets. We consider models with different jet velocities and variability, as well as a toroidal or helical magnetic field. Our simulations show that variable, low-density jets with velocities of ∼1000 km s{sup −1} and ∼10 times lighter than the environment can produce internal knots with significant synchrotron emission and thermal X-rays in the shocked region of the leading bow shock moving in a dense medium. While models with a purely toroidal magnetic field show a very large degree of polarization, models with a helical magnetic field show lower values and a decrease of the degree of polarization, in agreement with observations of protostellar jets.

  5. A laser flash absorption spectroscopy study of Anabaena sp. PCC 7119 flavodoxin photoreduction by photosystem I particles from spinach.

    PubMed

    Medina, M; Hervás, M; Navarro, J A; De la Rosa, M A; Gómez-Moreno, C; Tollin, G

    1992-11-30

    Electron transfer from P700 in photosystem I (PSI) particles from spinach to Anabaena sp. PCC 7119 flavodoxin has been studied using laser flash absorption spectroscopy. A non-linear protein concentration dependence of the rate constants was obtained, suggesting a two-step mechanism involving complex formation (k = 3.6 x 10(7) M-1.s-1) followed by intracomplex electron transfer (k = 270 s-1). The observed rate constants had a biphasic dependence on the concentrations of NaCl or MgCl2, with maximum values in the 40-80 mM range for NaCl and 4-12 mM for MgCl2. To our knowledge, this is the first time that the kinetics of PSI-dependent flavodoxin photoreduction have been determined.

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

    NASA Technical Reports Server (NTRS)

    Sander, Stanley P.; Friedl, Randall R.

    1989-01-01

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

  7. ALMA Studies of the Disk-Jet-Outflow Connection

    NASA Astrophysics Data System (ADS)

    Dougados, Catherine; Louvet, F.; Mardones, D.; Cabrit, S.

    2017-06-01

    I will describe in this contribution recent results obtained with ALMA on the origin of the disk/jet/outflow connexion in T Tauri stars. I will first present ALMA observations of the disk associated with the jet source Th 28, which question previous jet rotation measurements in this source and the implications drawn from them. I will then discuss Cycle 2 ALMA observations of the disk and small scale CO outflow associated with the prototypical edge-on HH 30 source. The unprecedented angular resolution of this dataset brings new constraints on the origin of the CO outflows in young stars.

  8. Study of the Strong Coupling Constant Using W+ Jet Processes

    NASA Astrophysics Data System (ADS)

    Abachi, S.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adam, I.; Adams, D. L.; Adams, M.; Ahn, S.; Aihara, H.; Alitti, J.; Álvarez, G.; Alves, G. A.; Amidi, E.; Amos, N.; Anderson, E. W.; Aronson, S. H.; Astur, R.; Avery, R. E.; Baden, A.; Balamurali, V.; Balderston, J.; Baldin, B.; Bantly, J.; Bartlett, J. F.; Bazizi, K.; Bendich, J.; Beri, S. B.; Bertram, I.; Bezzubov, V. A.; Bhat, P. C.; Bhatnagar, V.; Bhattacharjee, M.; Bischoff, A.; Biswas, N.; Blazey, G.; Blessing, S.; Bloom, P.; Boehnlein, A.; Bojko, N. I.; Borcherding, F.; Borders, J.; Boswell, C.; Brandt, A.; Brock, R.; Bross, A.; Buchholz, D.; Burtovoi, V. S.; Butler, J. M.; Carvalho, W.; Casey, D.; Castilla-Valdez, H.; Chakraborty, D.; Chang, S.-M.; Chekulaev, S. V.; Chen, L.-P.; Chen, W.; Chevalier, L.; Chopra, S.; Choudhary, B. C.; Christenson, J. H.; Chung, M.; Claes, D.; Clark, A. R.; Cobau, W. G.; Cochran, J.; Cooper, W. E.; Cretsinger, C.; Cullen-Vidal, D.; Cummings, M. A.; Cutts, D.; Dahl, O. I.; de, K.; Demarteau, M.; Demina, R.; Denisenko, K.; Denisenko, N.; Denisov, D.; Denisov, S. P.; Dharmaratna, W.; Diehl, H. T.; Diesburg, M.; di Loreto, G.; Dixon, R.; Draper, P.; Drinkard, J.; Ducros, Y.; Dugad, S. R.; Durston-Johnson, S.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Engelmann, R.; Eno, S.; Eppley, G.; Ermolov, P.; Eroshin, O. V.; Evdokimov, V. N.; Fahey, S.; Fahland, T.; Fatyga, M.; Fatyga, M. K.; Featherly, J.; Feher, S.; Fein, D.; Ferbel, T.; Finocchiaro, G.; Fisk, H. E.; Fisyak, Y.; Flattum, E.; Forden, G. E.; Fortner, M.; Frame, K. C.; Franzini, P.; Fuess, S.; Gallas, E.; Galyaev, A. N.; Gao, S. G.; Geld, T. L.; Genik, R. J., II; Genser, K.; Gerber, C. E.; Gibbard, B.; Glebov, V.; Glenn, S.; Gobbi, B.; Goforth, M.; Goldschmidt, A.; Gómez, B.; Goncharov, P. I.; González Solís, J. L.; Gordon, H.; Goss, L. T.; Graf, N.; Grannis, P. D.; Green, D. R.; Green, J.; Greenlee, H.; Griffin, G.; Grossman, N.; Grudberg, P.; Grünendahl, S.; Gu, W. X.; Guglielmo, G.; Guida, J. A.; Guida, J. M.; Guryn, W.; Gurzhiev, S. N.; Gutierrez, P.; Gutnikov, Y. E.; Hadley, N. J.; Haggerty, H.; Hagopian, S.; Hagopian, V.; Hahn, K. S.; Hall, R. E.; Hansen, S.; Hatcher, R.; Hauptman, J. M.; Hedin, D.; Heinson, A. P.; Heintz, U.; Hernández-Montoya, R.; Heuring, T.; Hirosky, R.; Hobbs, J. D.; Hoeneisen, B.; Hoftun, J. S.; Hsieh, F.; Hu, Tao; Hu, Ting; Hu, Tong; Huehn, T.; Igarashi, S.; Ito, A. S.; James, E.; Jaques, J.; Jerger, S. A.; Jiang, J. Z.-Y.; Joffe-Minor, T.; Johari, H.; Johns, K.; Johnson, M.; Johnstad, H.; Jonckheere, A.; Jones, M.; Jöstlein, H.; Jun, S. Y.; Jung, C. K.; Kahn, S.; Kalbfleisch, G.; Kang, J. S.; Kehoe, R.; Kelly, M. L.; Kernan, A.; Kerth, L.; Kim, C. L.; Kim, S. K.; Klatchko, A.; Klima, B.; Klochkov, B. I.; Klopfenstein, C.; Klyukhin, V. I.; Kochetkov, V. I.; Kohli, J. M.; Koltick, D.; Kostritskiy, A. V.; Kotcher, J.; Kourlas, J.; Kozelov, A. V.; Kozlovski, E. A.; Krishnaswamy, M. R.; Krzywdzinski, S.; Kunori, S.; Lami, S.; Landsberg, G.; Lebrat, J.-F.; Leflat, A.; Li, H.; Li, J.; Li, Y. K.; Li-Demarteau, Q. Z.; Lima, J. G.; Lincoln, D.; Linn, S. L.; Linnemann, J.; Lipton, R.; Liu, Y. C.; Lobkowicz, F.; Loken, S. C.; Lökös, S.; Lueking, L.; Lyon, A. L.; Maciel, A. K.; Madaras, R. J.; Madden, R.; Mandrichenko, I. V.; Mangeot, Ph.; Mani, S.; Mansoulié, B.; Mao, H. S.; Margulies, S.; Markeloff, R.; Markosky, L.; Marshall, T.; Martin, M. I.; Marx, M.; May, B.; Mayorov, A. A.; McCarthy, R.; McKibben, T.; McKinley, J.; McMahon, T.; Melanson, H. L.; de Mello Neto, J. R.; Merritt, K. W.; Miettinen, H.; Milder, A.; Mincer, A.; de Miranda, J. M.; Mishra, C. S.; Mohammadi-Baarmand, M.; Mokhov, N.; Mondal, N. K.; Montgomery, H. E.; Mooney, P.; Mudan, M.; Murphy, C.; Murphy, C. T.; Nang, F.; Narain, M.; Narasimham, V. S.; Narayanan, A.; Neal, H. A.; Negret, J. P.; Neis, E.; Nemethy, P.; NešiĆ, D.; Nicola, M.; Norman, D.; Oesch, L.; Oguri, V.; Oltman, E.; Oshima, N.; Owen, D.; Padley, P.; Pang, M.; Para, A.; Park, C. H.; Park, Y. M.; Partridge, R.; Parua, N.; Paterno, M.; Perkins, J.; Peryshkin, A.; Peters, M.; Piekarz, H.; Pischalnikov, Y.; Pluquet, A.; Podstavkov, V. M.; Pope, B. G.; Prosper, H. B.; Protopopescu, S.; Pušeljić, D.; Qian, J.; Quintas, P. Z.; Raja, R.; Rajagopalan, S.; Ramirez, O.; Rao, M. V.; Rapidis, P. A.; Rasmussen, L.; Read, A. L.; Reucroft, S.; Rijssenbeek, M.; Rockwell, T.; Roe, N. A.; Rubinov, P.; Ruchti, R.; Rusin, S.; Rutherfoord, J.; Santoro, A.; Sawyer, L.; Schamberger, R. D.; Schellman, H.; Sculli, J.; Shabalina, E.; Shaffer, C.; Shankar, H. C.; Shao, Y. Y.; Shivpuri, R. K.; Shupe, M.; Singh, J. B.; Sirotenko, V.; Smart, W.; Smith, A.; Smith, R. P.; Snihur, R.; Snow, G. R.; Snyder, S.; Solomon, J.; Sood, P. M.; Sosebee, M.; Souza, M.; Spadafora, A. L.; Stephens, R. W.; Stevenson, M. L.; Stewart, D.; Stoianova, D. A.; Stoker, D.; Streets, K.; Strovink, M.; Sznajder, A.; Taketani, A.; Tamburello, P.; Tarazi, J.; Tartaglia, M.; Taylor, T. L.; Teiger, J.; Thompson, J.; Trippe, T. G.; Tuts, P. M.; Varelas, N.; Varnes, E. W.; Virador, P. R.; Vititoe, D.; Volkov, A. A.; Vorobiev, A. P.; Wahl, H. D.; Wang, G.; Wang, J.; Warchol, J.; Wayne, M.; Weerts, H.; Wen, F.; Wenzel, W. A.; White, A.; White, J. T.; Wightman, J. A.; Wilcox, J.; Willis, S.; Wimpenny, S. J.; Wirjawan, J. V.; Womersley, J.; Won, E.; Wood, D. R.; Xu, H.; Yamada, R.; Yamin, P.; Yanagisawa, C.; Yang, J.; Yasuda, T.; Yoshikawa, C.; Youssef, S.; Yu, J.; Yu, Y.; Zhang, D. H.; Zhang, Y.; Zhu, Q.; Zhu, Z. H.; Zieminska, D.; Zieminski, A.; Zylberstejn, A.

    1995-10-01

    The ratio of the number of W+1 jet to W+0 jet events is measured with the D0 detector using data from the 1992-93 Tevatron Collider run. For the W-->eν channel with a minimum jet ET cutoff of 25 GeV, the experimental ratio is 0.065+/-0.003stat+/-0.007syst. Next-to-leading order QCD predictions for various parton distributions agree well with each other and are all over 1 standard deviation below the measurement. Varying the strong coupling constant αs in both the parton distributions and the partonic cross sections simultaneously does not remove this discrepancy.

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

    SciTech Connect

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

    1987-02-24

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

  10. Early Onset Hot Flashes May Signal Higher Heart Risks

    MedlinePlus

    ... medlineplus.gov/news/fullstory_164627.html Early Onset Hot Flashes May Signal Higher Heart Risks Study found ... 13, 2017 THURSDAY, April 13, 2017 (HealthDay News) -- Hot flashes may be more than a troublesome nuisance ...

  11. Ruthenium-phenothiazine electron transfer dyad with a photoswitchable dithienylethene bridge: flash-quench studies with methylviologen.

    PubMed

    He, Bice; Wenger, Oliver S

    2012-04-02

    A molecular ensemble composed of a phenothiazine (PTZ) electron donor, a photoisomerizable dithienylethene (DTE) bridge, and a Ru(bpy)(3)(2+) (bpy = 2,2'-bipyridine) electron acceptor was synthesized and investigated by optical spectroscopic and electrochemical means. Our initial intention was to perform flash-quench transient absorption studies in which the Ru(bpy)(3)(2+) unit is excited selectively ("flash") and its (3)MLCT excited state is quenched oxidatively ("quench") by excess methylviologen prior to intramolecular electron transfer from phenothiazine to Ru(III) across the dithienylethene bridge. However, after selective Ru(bpy)(3)(2+1)MLCT excitation of the dyad with the DTE bridge in its open form, (1)MLCT → (3)MLCT intersystem crossing on the metal complex is followed by triplet-triplet energy transfer to a (3)π-π* state localized on the DTE unit. This energy transfer process is faster than bimolecular oxidative quenching with methylviologen at the ruthenium site (Ru(III) is not observed); only the triplet-excited DTE then undergoes rapid (10 ns, instrumentally limited) bimolecular electron transfer with methylviologen. Subsequently, there is intramolecular electron transfer with PTZ. The time constant for formation of the phenothiazine radical cation via intramolecular electron transfer occurring over two p-xylene units is 41 ns. When the DTE bridge is photoisomerized to the closed form, PTZ(+) cannot be observed any more. Irrespective of the wavelength at which the closed isomer is irradiated, most of the excitation energy appears to be funneled rapidly into a DTE-localized singlet excited state from which photoisomerization to the open form occurs within picoseconds.

  12. Sensitivity of Orographic Moist Convection to Landscape Variability: A Study of the Buffalo Creek, Colorado, Flash Flood Case of 1996.

    NASA Astrophysics Data System (ADS)

    Chen, Fei; Warner, Thomas T.; Manning, Kevin

    2001-11-01

    A number of numerical experiments with a high-resolution mesoscale model were conducted to study the convective rainfall event that caused the 1996 Buffalo Creek, Colorado, flash flood. Different surface conditions and treatments of land surface physics were utilized to assess the sensitivity of this orographic moist convection to local and regional landscape forcing.Given accurate large-scale synoptic conditions at the lateral boundaries, the mesoscale model with a convection-resolving grid shows reasonably good skill in simulating this convective event with a lead time of up to 12 h. Sensitivity experiments show that a primary reason for this success is the use of an advanced land surface model that provides time-varying soil-moisture fields. This land surface model plays an important role in capturing the complex interactions among the land surface, the PBL, cloud-modulated radiation, and precipitation. For the case simulated, such interactions contribute to the temporal and spatial distribution of surface heating at small scales, and the convective triggering and development.Tests show that the landscape variability at small and large scales significantly affects the location and intensity of the moist convection. For example, on timescales of 6 to 12 h, differences in initial soil moisture associated with irrigation in the plains affect the evolution of the convection near the Continental Divide. Also, the surface modification by a wildfire burn influences the path of the major convective event that caused the flash flood.A watershed-based quantitative-precipitation-forecast skill score is proposed and employed. The relative success with which this severe thunderstorm is simulated over complex terrain provides some hope that the careful treatment of land surface physics in convection-resolving models can perhaps provide some useful level of predictability.

  13. Energetics of Photosystem II charge recombination in Acaryochloris marina studied by thermoluminescence and flash-induced chlorophyll fluorescence measurements.

    PubMed

    Cser, Krisztián; Deák, Zsuzsanna; Telfer, Alison; Barber, James; Vass, Imre

    2008-01-01

    We studied the charge recombination characteristics of Photosystem II (PSII) redox components in whole cells of the chlorophyll (Chl) d-dominated cyanobacterium, Acaryochloris marina, by flash-induced chlorophyll fluorescence and thermoluminescence measurements. Flash-induced chlorophyll fluorescence decay was retarded in the mus and ms time ranges and accelerated in the s time range in Acaryochloris marina relative to that in the Chl a-containing cyanobacterium, Synechocystis PCC 6803. In the presence of 3-(3,4-dichlorophenyl)-1, 1-dimethylurea, which blocks the Q(B) site, the relaxation of fluorescence decay arising from S(2)Q(A)(-) recombination was somewhat faster in Acaryochloris marina than in Synechocystis PCC 6803. Thermoluminescence intensity of the so called B band, arising from the recombination of the S(2)Q(B)(-) charge separated state, was enhanced significantly (2.5 fold) on the basis of equal amounts of PSII in Acaryochloris marina as compared with Synechocystis 6803. Our data show that the energetics of charge recombination is modified in Acaryochloris marina leading to a approximately 15 meV decrease of the free energy gap between the Q(A) and Q(B) acceptors. In addition, the total free energy gap between the ground state and the excited state of the reaction center chlorophyll is at least approximately 25-30 meV smaller in Acaryochloris marina, suggesting that the primary donor species cannot consist entirely of Chl a in Acaryochloris marina, and there is a contribution from Chl d as well.

  14. Hot flashes in breast cancer survivors: Frequency, severity and impact.

    PubMed

    Chang, Hao-Yuan; Jotwani, Aparna C; Lai, Yeur-Hur; Jensen, Mark P; Syrjala, Karen L; Fann, Jesse R; Gralow, Julie

    2016-06-01

    To (1) determine the frequency and severity of hot flashes, (2) examine the associations between hot flash frequency and severity and quality of life, and (3) identify the predictors of hot flash activity in breast cancer survivors. The study used a cross-sectional design and mailed survey of 253 breast cancer survivors recruited from a cancer wellness clinic. Participants provided information regarding cancer history, hot flashes, pain intensity, sleep problems, physical functioning, and psychological functioning. About half of the survivors reported at least one hot flash in the past 24 h (45%) or past week (52%). The average frequency of hot flashes was 1.9 in the past 24 h and 1.8 in the past week. Hot flash severity was usually mild or asymptomatic. However, participants with hot flashes reported significantly more sleep problems and higher pain severity than those reporting no hot flashes. Moreover, the severity of hot flashes was associated with more sleep problems, higher pain severity, and more psychological dysfunction. History of hormonal suppression therapy and younger age predicted hot flash activity in the study sample. In breast cancer survivors, hot flashes are common and are associated with unpleasant symptoms and poor quality of life. Research is needed to determine if treatments that reduce the frequency and severity of hot flashes in breast cancer survivors also result in improvements in symptoms such as sleep problems, pain, and psychological dysfunction. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Experimental Study of Impinging Jets Flow-Fields

    DTIC Science & Technology

    2016-07-27

    the jet plumes and outwash flow . Lift plate surface pressure measurements have also been made. The unsteady flow , known to have significant large...contributed to the identification and measurement of the major features of the flow -field generated by the two parallel impinging model jets. These...and outwash flow . 3 Laser Doppler Velocimeter Measurements Highlights of the LDV measurements are presented in the next two figures

  16. Alcohol-to-Jet (ATJ) Fuel Blending Study

    DTIC Science & Technology

    2015-09-01

    to-Jet (ATJ) fuels are slowly making their way through the approval process at ASTM as candidate aviation fuels or blendstocks. To expand upon...to-Jet (ATJ) fuels are slowly making their way through the approval process at ASTM as candidate aviation fuels or blendstocks. Extensive testing...and 100 °C per ASTM D445 • Derived Cetane Number (DCN) per ASTM D6890 • Cetane Number per ASTM D613 (modified) • Lubricity (BOCLE) per ASTM D 5001

  17. Characterization and validation of an anechoic facility for high-temperature jet noise studies

    NASA Astrophysics Data System (ADS)

    Craft, Joseph

    In response to the increasing demand for jet noise studies performed at realistic conditions, the Florida Center For Advanced Aero-Propulsion at Florida State University has recently brought online an upgraded Anechoic High-Temperature Jet Facility. The function of this facility is to accurately simulate and characterize the aeroacoustic properties of exhaust from jet engines at realistic temperatures and flow speeds. This new addition is a blow-down facility supplied by a 3500 kPa, 114 cubic meter compressed dry air system and a sudden-expansion ethylene burner that is capable of producing ideally expanded jets up to Mach 2.6 and stagnation temperatures up to 1500 K. The jet exhausts into a fully anechoic chamber which is equipped to acquire acoustic and flow measurements including the temperature and pressure of the jet. The facility is capable of operating under free jet as well as in various impinging jet configurations pertinent to sea- and land-based aircraft, such as the F-35B. Compared to the original facility, the updated rig is capable of longer run times at higher temperatures. In this paper we demonstrate the facility's experimental capabilities and document jet aeroacoustic characteristics at various flow and temperature conditions. The anechoic chamber was characterized using ISO (3745:2003) guidelines and the lower cutoff frequency of the chamber was determined to be 315 Hz. Aeroacoustic properties of jets operating at subsonic conditions and supersonic Mach numbers ranging from 1.2 to 2.1 at temperatures of 300 K to 1300 K are documented. Where available, very good agreement was found when the present results were compared with data in the jet noise literature.

  18. A 1D (radial) Plasma Jet Propagation Study for the Plasma Liner Experiment (PLX)

    NASA Astrophysics Data System (ADS)

    Thompson, J. R.; Bogatu, I. N.; Galkin, S. A.; Kim, J. S.; Welch, D. R.; Thoma, C.; Golovkin, I.; Macfarlane, J. J.; Case, A.; Messer, S. J.; Witherspoon, F. D.; Cassibry, J. T.; Awe, T. J.; Hsu, S. C.

    2011-10-01

    The Plasma Liner Experiment will explore the formation of imploding spherical ``plasma liners'' that reach peak pressures of 0.1 Mbar upon stagnation. The liners will be formed through the merging of dense, high velocity plasma jets (n ~1017 cm-3, T ~3 eV, v ~50 km/s) in a spherically convergent geometry. The focus of this 1D (radial) study is argon plasma jet evolution during propagation from the rail gun source to the jet merging radius. The study utilizes the Large Scale Plasma (LSP) PIC code with atomic physics included through the use of a non-Local Thermal Equilibrium (NLTE) Equation of State (EOS) table. We will present scenarios for expected 1D (radial) plasma jet evolution, from upon exiting the PLX rail gun to reaching the jet merging radius. The importance of radiation cooling early in the simulation is highlighted. Work supported by US DOE grant DE-FG02-05ER54835.

  19. Study of Decay Characteristics of Hexagonal and Square Supersonic Jet

    NASA Astrophysics Data System (ADS)

    Mohanta, Prasanta Kumar; Sridhar, B. T. N.

    2017-05-01

    Experiments were carried on nozzles with different exit geometry to study their impact on supersonic core length. Circular, hexagonal, and square exit geometries were considered for the study. Numerical simulations and schlieren image study were performed. The supersonic core decay was found to be of different length for different exit geometries, though the throat to exit area ratio was kept constant. The impact of nozzle exit geometry is to enhance the mixing of primary flow with ambient air, without requiring tab, wire or secondary method to increase the mixing characteristics. The non-circular mixing is faster comparative to circular geometry, which leads to reduction in supersonic core length. The results depict that shorter the hydraulic diameter, the jet mixing is faster. To avoid the losses in divergent section, the cross section of throat was maintained at same geometry as the exit geometry. Investigation shows that the supersonic core region is dependent on the hydraulic diameter and the diagonal. In addition, it has been observed that number of shock cells remain the same irrespective of exit geometry shape for the given nozzle pressure ratio.

  20. Monte Carlo study of Quark Gluon Plasma using photon jet observables

    NASA Astrophysics Data System (ADS)

    Xing, Tian

    2016-09-01

    Relativistic heavy ion collisions create an exotic state of deconfined, nuclear matter called quark gluon plasma (QGP), providing an opportunity to study the strong interaction. In some particularly hard scattered events, a parton with high transverse momentum (pT) interacts with this medium before fragmenting into a spray of particles, called a jet. Jet properties of heavy ion collisions can be modified relative to expectations from pp collisions; this effect is called jet quenching. Measurement of the jet internal structure can provide information about this effect and about the medium itself. On the other hand, studying systems whose jets are recoiled against photons coming from an initial scattering offers a way to calibrate the momentum of the modified jet. Since photons do not carry color charge, they escape the QGP with their initial momentum intact. On this poster, results using the Monte Carlo event generators Pythia and JEWEL will be presented for fragmentation functions and jet suppression from photon-jet events, alongside experimental data from CMS and ATLAS at a center of mass energy of 2.76 TeV. Predictions are also presented for lead-lead collisions at a center of mass energy of 5.02 TeV.

  1. Turbulence in Reynolds' flashes

    NASA Astrophysics Data System (ADS)

    Cerbus, Rory; Liu, Chien-Chia; Gioia, Gustavo; Chakraborty, Pinaki

    2016-11-01

    Osborne Reynolds' seminal work from 1883 revealed that the transition from quiescent, laminar flow to a turbulent pipe filled with roiling eddies is mediated by localized flashes of fluctuations. Later work has unveiled many features of these flashes: they proliferate or fade away, maintain their shape or continually expand. The nature of the fluctuations in the flashes, however, has remained mysterious. Here, using measures traditionally attributed to high Reynolds number (Re) flows, we present experimental results on the fluctuations of the flashes. Our results suggest that the transition to turbulence is the low Re limit of the high Re, fully developed flow. Okinawa Institute of Science and Technology.

  2. Flash protection controller

    DOEpatents

    Galbraith, Lee K.

    1981-01-01

    A controller provides a high voltage to maintain an electro-optic shutter in a transparent condition until a flash of light which would be harmful to personnel is sensed by a phototransistor. The controller then shorts the shutter to ground to minimize light transmission to the user and maintains light transmission at the pre-flash level for a predetermined time to allow the flash to subside. A log converter and differential trigger circuit keep the controller from being triggered by other light flashes which are not dangerous.

  3. Flash protection controller

    DOEpatents

    Galbraith, L.K.

    1979-12-07

    A controller provides a high voltage to maintain an electro-optic shutter in a transparent condition until a flash of light which would be harmful to personnel is sensed by a phototransistor. The controller then shorts the shutter to ground to minimize light transmission to the user and maintains light transmission at the pre-flash level for a predetermined time to allow the flash to subside. A log converter and differential trigger circuit keep the controller from being triggered by other light flashes which are not dangerous.

  4. Mixing Near the Subtropical Jet - a Case Study

    NASA Astrophysics Data System (ADS)

    Pan, L. L.; Randel, W. J.; Browell, E.; Mahoney, M. J.

    2003-12-01

    Mixing is an important part of irreversible stratosphere troposphere exchange. Yet the mixing process is poorly understood. We present a case study of mixing in the vicinity of the subtropical jet, using airborne in situ and remote sensing data during SONEX mission. The case of intrusion of stratospheric air is identified using ozone profile curtains from DIAL LIDAR onboard DC-8. The thermal structure across the tropopause is mapped using temperature profiles from Microwave Temperature Profiler (MTP), together with the potential vorticity field based on the ECMWF data. Spatial extent of mixing between stratospheric and tropospheric air is examined using tracer relationships from in situ measurement onboard DC-8. Results show that mixing between stratospheric and tropospheric air involved air mass with ozone value up to ~400 ppbv. The case study also show that based on the tracer relationship alone, without the background information provided by the LIDAR data and MTP data, it is often difficult to conclude whether the observed mixing represent stratosphere to troposphere transport or troposphere to stratosphere transport. Results also show that using 2 PVU or 3.5 PVU contour as the tropopause in this case will likely underestimate the stratosphere to troposphere transport.

  5. Jet pumps for thermoacoustic applications: Design guidelines based on a numerical parameter study.

    PubMed

    Oosterhuis, Joris P; Bühler, Simon; Wilcox, Douglas; van der Meer, Theo H

    2015-10-01

    The oscillatory flow through tapered cylindrical tube sections (jet pumps) is characterized by a numerical parameter study. The shape of a jet pump results in asymmetric hydrodynamic end effects which cause a time-averaged pressure drop to occur under oscillatory flow conditions. Hence, jet pumps are used as streaming suppressors in closed-loop thermoacoustic devices. A two-dimensional axisymmetric computational fluid dynamics model is used to calculate the performance of a large number of conical jet pump geometries in terms of time-averaged pressure drop and acoustic power dissipation. The investigated geometrical parameters include the jet pump length, taper angle, waist diameter, and waist curvature. In correspondence with previous work, four flow regimes are observed which characterize the jet pump performance and dimensionless parameters are introduced to scale the performance of the various jet pump geometries. The simulation results are compared to an existing quasi-steady theory and it is shown that this theory is only applicable in a small operation region. Based on the scaling parameters, an optimum operation region is defined and design guidelines are proposed which can be directly used for future jet pump design.

  6. Experimental study on the lethal threshold value of multiple successive voltage impulses to rabbits simulating multi-stroke lightning flash

    NASA Astrophysics Data System (ADS)

    Ishikawa, T.; Ohashi, M.; Kitagawa, N.; Nagai, Y.; Miyazawa, T.

    1985-06-01

    It is well known that about three-quarters of a lightning discharge to the ground consists of multi-stroke flashes among which 3- or 4-stroke flashes are the most frequent. A new type of impulse-generator was developed which can produce 3-successive impulse voltages to simulate multi-stroke lightning flashes. Experiments were conducted to investigate the effects of multi-stroke flash on the living body and the results were compared with those for the well-known effects of a single-stroke discharge. The results demonstrated that in the case of the multi-stroke discharge, the animal died when of the energy of one of the individual impulses reached the lethal threshold value established for a single-stroke discharge. It was found that the effect of the individual impulses did not last longer than the stroke interval and did not exert an additive effect on the living body. In natural lightning discharges, the multi-stroke flash should be regarded as more dangerous than the single-stroke flash, since it is liable to an energy that exceeds the lethal threshold value and to be associated with a higher probability of a continuing current (known to be the most fatal of discharge components).

  7. Study of high-p T hadron-jet correlations in ALICE

    NASA Astrophysics Data System (ADS)

    Krizek, Filip; ALICE Collaboration

    2017-02-01

    We report the measurement of semi-inclusive p T spectra of charged particle jets that recoil from a high-p T hadron trigger in Pb–Pb and pp collisions at \\sqrt {{s{{NN}}}} = 2.76{{ TeV}} and \\sqrt s = 7{{ TeV}}, respectively. In this analysis, the copious yield of uncorrelated trigger hadron-jet matchings in central Pb–Pb collisions is removed by calculating the difference between two spectra corresponding to exclusive trigger hadron p T ranges. This procedure does not impose any fragmentation bias on the recoil jet population, which is therefore collinear and infrared safe. The resulting distributions obtained for different values of jet resolution parameter are used to study the modification of jet structure in the medium.

  8. Study of Coronal Jets During Solar Minimum Based on STEREO/SECCHI Observations

    NASA Astrophysics Data System (ADS)

    Paraschiv, A. R.; Lacatus, D. A.; Badescu, T.; Lupu, M. G.; Simon, S.; Sandu, S. G.; Mierla, M.; Rusu, M. V.

    2010-07-01

    During the 2007 - 2008 minimum of solar activity, the internally occulted coronagraphs SECCHI-COR1 onboard the STEREO space mission recorded numerous jet-like ejections over a great range of latitudes. We have found more than 10000 white-light jets in the above-mentioned period. Sometimes they can be identified on the disk with bright points observed in ultraviolet images by EUVI. In this study we present a catalog consisting of jets observed by the SECCHI-COR1 instrument and their association with lower coronal activity (bright points, UV jets). Furthermore, their association with bright points in the context of previously proposed models is discussed. From the complete catalog we have selected 106 jets observed in both STEREO-A and STEREO-B images for which it is possible to derive their kinematics and point of origin.

  9. NICA fixed target mode: Soft jet studies in the relative 4-velocity space

    NASA Astrophysics Data System (ADS)

    Okorokov, V. A.

    2016-08-01

    Experimental results obtained by studying the properties of soft jets in the 4-velocity space at √{{s}} ˜ 2-20 GeV are presented. The changes in the mean distance from the jet axis to the jet particles, the mean kinetic energy of these particles, and the cluster dimension in response to the growth of the collision energy are consistent with the assumption that quark degrees of freedom manifest themselves in processes of pion-jet production at intermediate energies. The energy at which quark degrees of freedom begin to manifest themselves experimentally in the production of soft pion jets is estimated for the first time. The estimated value of this energy is 2.8±0.6 GeV. The suggestions are made for future investigations on NICA.

  10. Flash Expansion Threshold in Whirligig Swarms.

    PubMed

    Romey, William L; Lamb, Alicia R

    2015-01-01

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

  11. Runaway beam studies during disruptions at JET-ILW

    NASA Astrophysics Data System (ADS)

    Reux, C.; Plyusnin, V.; Alper, B.; Alves, D.; Bazylev, B.; Belonohy, E.; Brezinsek, S.; Decker, J.; Devaux, S.; de Vries, P.; Fil, A.; Gerasimov, S.; Lupelli, I.; Jachmich, S.; Khilkevitch, E. M.; Kiptily, V.; Koslowski, R.; Kruezi, U.; Lehnen, M.; Manzanares, A.; Mlynář, J.; Nardon, E.; Nilsson, E.; Riccardo, V.; Saint-Laurent, F.; Shevelev, A. E.; Sozzi, C.

    2015-08-01

    Runaway electrons (RE) during disruptions are a concern for future tokamaks including ITER with its metallic wall. Although RE are rare in spontaneous disruptions with the JET ITER-like Wall (JET-ILW), RE beams up to 380 kA were obtained using massive injection (MGI) of argon in JET-ILW divertor discharges. Entry points into the RE domain defined by operational parameters (toroidal field, argon fraction in MGI) are unchanged but higher RE currents have been obtained inside the JET-ILW MGI-generated RE domain when compared to JET-C. This might be due to the influence of the metallic wall on the current quench plasma. Temperatures of 900 °C have been observed following RE impacts on beryllium tiles. Heat deposition depth of ∼2 mm has to be assumed to match the tile cooling time. 3D simulations of the RE energy deposition using the ENDEP/MEMOS codes show that material melting is unlikely with 100 kA RE beams.

  12. Space shuttle orbiter reaction control system jet interaction study

    NASA Technical Reports Server (NTRS)

    Rausch, J. R.

    1975-01-01

    The space shuttle orbiter has forward mounted and rear mounted Reaction Control Systems (RCS) which are used for orbital maneuvering and also provide control during entry and abort maneuvers in the atmosphere. The effects of interaction between the RCS jets and the flow over the vehicle in the atmosphere are studied. Test data obtained in the NASA Langley Research Center 31 inch continuous flow hypersonic tunnel at a nominal Mach number of 10.3 is analyzed. The data were obtained with a 0.01 scale force model with aft mounted RCS nozzles mounted on the sting off of the force model balance. The plume simulations were accomplished primarily using air in a cold gas simulation through scaled nozzles, however, various cold gas mixtures of Helium and Argon were also tested. The effect of number of nozzles was tested as were limited tests of combined controls. The data show that RCS nozzle exit momentum ratio is the primary correlating parameter for effects where the plume impinges on an adjacent surface and mass flow ratio is the parameter where the plume interaction is primarily with the external stream. An analytic model of aft mounted RCS units was developed in which the total reaction control moments are the sum of thrust, impingement, interaction, and cross-coupling terms.

  13. High resolution LES study of the nocturnal low level jet

    NASA Astrophysics Data System (ADS)

    Giometto, Marco; Calaf, Marc; Oldroyd, Holly; Fang, Jiannong; Parlange, Marc B.

    2013-04-01

    Katabatic winds are buoyantly driven flows arising along cooled sloping surfaces which play a crucial role in driving the local weather, redistributing scalars such as temperature and moisture in the atmosphere. These winds are established following sunset under strong radiational cooling and rapidly stop after dawn with the formation of the convective boundary layer. They are characterized by a peak in the along slope velocity known as nocturnal low level jet (LLJ) whose effects, on the dynamics of such systems, have been recently investigated but are still not fully understood. The current contribution proposes a Large Eddy Simulation (LES) study at high resolution of idealized katabatic flows along cooled sloping surfaces and aims at gaining a deeper understanding on those that are the dynamics of such thermodynamical systems at the LLJ height. The stably stratified atmosphere is approximated in the Boussinesq sense, rotational effects are not taken into account and the subgrid terms for momentum and buoyancy are independently parametrized adopting Lagrangian scale dependent dynamic models (Bou Zeid et al., 2005). The structure of the mean and turbulent fields obtained from our numerical setup is analysed and results are compared with recent literature and meteorological observations from a narrow alpine valley with steep slopes (Val Ferret, Switzerland). The importance of the subgrid parametrization is tested via run at various resolution.

  14. Investigating the role of geology in the hydrological response of Mediterranean catchments prone to flash-floods: Regional modelling study and process understanding

    NASA Astrophysics Data System (ADS)

    Vannier, Olivier; Anquetin, Sandrine; Braud, Isabelle

    2016-10-01

    In this study, a regional distributed hydrological model is used to perform long-term and flash-flood event simulations, over the Cévennes-Vivarais region (south of France). The objective is to improve our understanding on the role played by geology on the hydrological processes of catchments during two past flash-flood events. This modelling work is based on Vannier et al. ("Regional estimation of catchment-scale soil properties by means of streamflow recession analysis for use in distributed hydrological models", Hydrological Processes, 2014), where streamflow recessions are analysed to estimate the thickness and hydraulic conductivity of weathered rock layers, depending on the geological nature of catchments. Weathered rock layers are thus implemented into the hydrological model CVN-p, and the contribution of these layers is assessed during flash-flood events simulations as well as during inter-event periods. The model is used without any calibration, to test hypotheses on the active hydrological processes. The results point out two different hydrological behaviours, depending on the geology: on crystalline rocks (granite and gneiss), the addition of a weathered rock layer considerably improves the simulated discharges, during flash-flood events as well as during recession periods, and makes the model able to remarkably reproduce the observed streamflow dynamics. For other geologies (schists especially), the benefits are real, but not sufficient to properly simulate the observed streamflow dynamics. These results probably underline the existence of poorly known processes (flow paths, non-linear spilling process) associated with the planar structure of schisty rocks. On a methodological point of view, this study proposes a simple way to account for the additional storage associated with each geological entity, through the addition of a weathered porous rock layer situated below the traditionally-considered upper soil horizons, and shows its applicability and

  15. Multiwavelength study of 20 jets that emanate from the periphery of active regions

    NASA Astrophysics Data System (ADS)

    Mulay, Sargam M.; Tripathi, Durgesh; Del Zanna, Giulio; Mason, Helen

    2016-05-01

    Aims: We present a multiwavelength analysis of 20 EUV jets which occurred at the periphery of active regions close to sunspots. We discuss the physical parameters of the jets and their relation with other phenomena such as Hα surges, nonthermal type-III radio bursts and hard X-ray (HXR) emission. Methods: These jets were observed between August 2010 and June 2013 by the Atmospheric Imaging Assembly (AIA) instrument that is onboard the Solar Dynamic Observatory (SDO). We selected events that were observed on the solar disk within +/-60° latitude. Using AIA wavelength channels that are sensitive to coronal temperatures, we studied the temperature distribution in the jets using the line of sight (LOS) differential emission measure (DEM) technique. We also investigated the role of the photospheric magnetic field using the LOS magnetogram data from the Helioseismic and Magnetic Imager (HMI) onboard SDO. Results: It has been observed that most of the jets originated from the western periphery of active regions. Their lifetimes range from 5 to 39 min with an average of 18 min and their velocities range from 87 to 532 km s-1 with an average of 271 km s-1. All the jets are co-temporally associated with Hα surges. Most of the jets are co-temporal with nonthermal type-III radio bursts observed by the Wind/WAVES spacecraft in the frequency range from 20 kHz to 13 MHz. We confirm the source region of these bursts using the potential field source surface (PFSS) technique. Using Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) observations, we found that half of the jets produced HXR emission and they often shared the same source region as the HXR emission (6-12 keV). Ten out of 20 events showed that the jets originated in a region of flux cancellation and six jets in a region of flux emergence. Four events showed flux emergence and then cancellation during the jet evolution. DEM analyses showed that for most of the spires of the jets, the DEM peaked at around log

  16. A numerical study of drop-on-demand ink jets

    NASA Technical Reports Server (NTRS)

    Fromm, J.

    1982-01-01

    Ongoing work related to development and utilization of a numerical model for treating the fluid dynamics of ink jets is discussed. The model embodies the complete nonlinear, time dependent, axi-symmetric equations in finite difference form. The jet nozzle geometry with no-slip boundary conditions and the existence of a contact circle are included. The contact circle is allowed some freedom of movement, but wetting of exterior surfaces is not addressed. The principal objective in current numerical experiments is to determine what pressure history, in conjunction with surface forces, will lead to clean drop formation.

  17. Theoretical and experimental study on the ejector augmented jet flap

    NASA Technical Reports Server (NTRS)

    Stewart, H. J.

    1974-01-01

    The analytical concept used in determining the characteristics of jet flap or related propulsive systems suitable for VTOL and STOL applications was examined. The configuration chosen was a two dimensional wing with a biplane flap, having a jet injected on the upper surface of the wing at the flap hinge axis and discharging into the channel between the two elements of the flap. The experimental work was conducted in a two dimensional test installation in a subsonic wind tunnel. The model description, the test conditions, and a summary of the experimental results are presented.

  18. Experimental approaches for studying non-equilibrium atmospheric plasma jets

    SciTech Connect

    Shashurin, A.; Keidar, M.

    2015-12-15

    This work reviews recent research efforts undertaken in the area non-equilibrium atmospheric plasma jets with special focus on experimental approaches. Physics of small non-equilibrium atmospheric plasma jets operating in kHz frequency range at powers around few Watts will be analyzed, including mechanism of breakdown, process of ionization front propagation, electrical coupling of the ionization front with the discharge electrodes, distributions of excited and ionized species, discharge current spreading, transient dynamics of various plasma parameters, etc. Experimental diagnostic approaches utilized in the field will be considered, including Rayleigh microwave scattering, Thomson laser scattering, electrostatic streamer scatterers, optical emission spectroscopy, fast photographing, etc.

  19. Study of Jet Formation in Wire X-pinches

    SciTech Connect

    Beg, F.N.; Ross, I.; Zhu, Y.; Dangor, A.E.; Krushelnick, K.

    2006-01-05

    Observations of x-pinch discharges driven by the 160 kA, 80 ns IMP generator are reported. X-pinches consisting of two wires of aluminum and molybdenum were used. X-pinches were mounted at two angles (120 deg. and 83 deg. ). The coronal plasma from the wires was observed to be streaming towards the mid plane of an x-pinch, forming jets on either side of the cross-point. Streaming of the coronal plasma was significant for a narrow angle and jets were observed to be m=1 unstable indicating a transfer of current.

  20. Analytical study of the twin-jet shielding

    NASA Technical Reports Server (NTRS)

    Gerhold, C. H.

    1983-01-01

    The development of the analytical model of twin-jet shielding is summarized. The models consist of a point noise source impinging on a cylinder of heated flow in which the temperature and flow velocity are uniform cross the cross section. In the formulation of the model, the wave equations are written for the regions outside the flow and within the flow cylinder. The solutions to the wave equations are matched at the jet boundary under the conditions of continuity of pressure and continuity of the vortex sheet. The solution reduces to an indefinite integral involving Bessel functions. The integral is solved approximately using a saddle point method.

  1. Flash-Type Discrimination

    NASA Technical Reports Server (NTRS)

    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.

  2. Flash Platform Examination

    DTIC Science & Technology

    2011-03-01

    MiniBuilder ................................................................................................. 111 4.5 Alchemy ...is an online open source IDE for ActionScript created using ActionScript. 112 DRDC Atlantic TM 2008-291 4.5 Alchemy A final...noteworthy item in considering tooling for the flash platform is Alchemy ; a set of developer tools for creating Flash applications from C and C++ source code

  3. Experimental study of cooling performance of pneumatic synthetic jet with singular slot rectangular orifice

    NASA Astrophysics Data System (ADS)

    Yu, Roger Ho Zhen; Ismail, Mohd Azmi bin; Ramdan, Muhammad Iftishah; Mustaffa, Nur Musfirah binti

    2017-03-01

    Synthetic Jet generates turbulence flow in cooling the microelectronic devices. In this paper, the experiment investigation of the cooling performance of pneumatic synthetic jet with single slot rectangular orifices at low frequency motion is presented. The velocity profile at the end of the orifice was measured and used as characteristic performance of synthetic jet in the present study. Frequencies of synthetic jet and the compressed air pressure supplied to the pneumatic cylinder (1bar to 5bar) were the parameters of the flow measurement. The air velocity of the synthetic jet was measured by using anemometer air flow meter. The maximum air velocity was 0.5 m/s and it occurred at frequency motion of 8 Hz. The optimum compressed air supplied pressure of the synthetic jet study was 4 bar. The cooling performance of synthetic jet at several driven frequencies from 0 Hz to 8 Hz and heat dissipation between 2.5W and 9W were also investigate in the present study. The results showed that the Nusselt number increased and thermal resistance decreased with both frequency and Reynolds number. The lowest thermal resistance was 5.25°C/W and the highest Nusselt number was 13.39 at heat dissipation of 9W and driven frequency of 8Hz.

  4. A performance application study of a jet-flap helicopter rotor

    NASA Technical Reports Server (NTRS)

    Sullivan, R. J.; Laforge, S.; Holchin, B. W.

    1972-01-01

    A performance study was made of the application of a jet-flap to a reaction-drive rotor for a heavy-lift helicopter mission and for a high-speed-helicopter maneuverability (200 knots, 2g) mission. The results of the study are as follows: As a result of the increase in maximum airfoil lift coefficient achieved by the jet-flap, rotor solidity is reduced with the jet-flap to approximately 59% of a nonjet-flap rotor. As a result of the saving in rotor solidity, and hence in rotor weight, the jet-flap configuration had a 21% higher productivity than a nonjet-flap configuration. Of the three propulsion systems studied utilizing a jet-flap (hot cycle, warm cycle, cold cycle) the hot cycle gave the largest increase in productivity. The 200 knot 2g mission is performed best with a warm cycle propulsion system. The jet-flap permits designing for a rotor blade loading coefficient C sub T/sigma = .170 at 2g without encountering blade stall. The jet-flap rotor permits a 200 knot 2g maneuver without suffering the penalty of an unreasonable rotor solidity that would be required by a nonjet-flap rotor.

  5. Cloud-to-ground lightning flashes and debris-flow-generating rainfall in the post wildfire environment: An exploratory study of the Mitchell Creek debris flow in western Colorado, summer 2002

    NASA Astrophysics Data System (ADS)

    Underwood, S. Jeffrey; Schultz, Michael D.

    2003-09-01

    Cloud-to-ground (CG) lightning flash parameters collected by the National Lightning Detection Network were analyzed in conjunction with rainfall observations near Mitchell Creek (MC) at the Coal Seam Wildfire site in western Colorado, USA. Nine thunderstorms produced significant CG flashes in the area surrounding MC from 28 June (fire containment) to 5 August 2002. A debris flow was generated at MC by one of these storms at ˜2058 LT on 5 August 2002. This study compares the CG flash parameters and rainfall characteristics of the 5 August thunderstorm with the eight thunderstorms (control group) that did not produce a hazardous hydrologic response at MC. The CG flash patterns and a synoptic analysis suggest that the 5 August thunderstorms occurred during a North American Monsoon "burst" period with a strong southwesterly surge of moisture advecting as far north as central Wyoming. The 5 August thunderstorm sequence was bimodal and more intense in terms of CG flash totals and rainfall rates than the control group. Moist southwesterly flow at lower levels and dry southeasterly flow in the upper troposphere may have enhanced orographically forced convection during the evening of 5 August. CG flashes and rainfall at spatial scales of 100 × 100 km, 50 × 50 km, and 25 × 25 km around MC confirm that the 5 August episode was more intense than any of the control group. The analysis concluded that the time of first flash and the number of consecutive 5-min intervals with CG flashes were temporally related with intense rainfall at the debris flow site. Additionally, there was a strong correlation between flash clusters within 40 km of MC and rainfall intensity at the site. The results of this study suggest that CG flash parameters may prove beneficial in modeling rainfall intensity thresholds in areas burned by wildfire.

  6. Study and optimization of negative polarity rod pinch diode as flash radiography source at 4.5 MV

    NASA Astrophysics Data System (ADS)

    Etchessahar, Bertrand; Bernigaud, Virgile; Caron, Michel; Cartier, Frédéric; Cartier, Stéphanie; Hourdin, Laurent; Magnin, Laurent; Nicolas, Rémi; Poulet, Frédéric; Rosol, Rodolphe; Tailleur, Yaël; Toury, Martial; Compant La Fontaine, Antoine; Bicrel, Béatrice; Cassany, Bruno; Desanlis, Thierry; Voisin, Luc; Hébert, David; Delbos, Christophe; Garrigues, Alain; Soleilhavoup, Isabelle

    2012-09-01

    The negative polarity rod pinch diode (NPRPD) is a potential millimeter spot size radiography source for high voltage generators (4 to 8 MV) [Cooperstein et al., "Considerations of rod-pinch diode operation in negative polarity for radiography," in Proceedings of the 14th IEEE Pulsed Power Conference, 2003, pp. 975-978]. The NPRPD consists of a small diameter (few mm) cylindrical anode extending from the front end of the vacuum cell through a thin annular cathode, held by a central conductor. The polarity has been inverted when compared to the original rod pinch diode [Cooperstein et al., "Theoretical modeling and experimental characterization of a rod-pinch diode," Phys. Plasmas 8(10), 4618-4636 (2001)] in order to take advantage from the maximal x-ray emission toward the anode holder at such a voltage [Swanekamp et al., "Evaluation of self-magnetically pinched diodes up to 10 MV as high resolution flash X-ray sources," IEEE Trans. Plasma Sci. 32(5), 2004-2016 (2004). We have studied this diode at 4.5 MV, driven by the ASTERIX generator [Raboisson et al., "ASTERIX, a high intensity X-ray generator," in Proceedings of the 7th IEEE Pulsed Power Conference, 1989, pp. 567-570.]. This generator, made up of a capacitor bank and a Blumlein line, was initially designed to test the behavior of electronic devices under irradiation. In our experiments, the vacuum diode has been modified in order to set up flash a radiographic diode [Etchessahar et al., "Negative polarity rod pinch diode experiments on the ASTERIX generator," in Conference Records-Abstracts, 37th IEEE International Conference on Plasma Science, 2010]. The experiments and numerical simulations presented here allowed the observation and analysis of various physical phenomena associated with the diode operation. Also, the influence of several experimental parameters, such as cathode and anode diameters, materials and surface states, was examined. In order to achieve the most comprehensive characterization of the

  7. Study and optimization of negative polarity rod pinch diode as flash radiography source at 4.5 MV

    SciTech Connect

    Etchessahar, Bertrand; Bicrel, Beatrice; Cassany, Bruno; Desanlis, Thierry; Voisin, Luc; Hebert, David; Bernigaud, Virgile; Magnin, Laurent; Nicolas, Remi; Poulet, Frederic; Tailleur, Yaeel; Caron, Michel; Cartier, Frederic; Cartier, Stephanie; Hourdin, Laurent; Rosol, Rodolphe; Toury, Martial; Delbos, Christophe; Garrigues, Alain; Soleilhavoup, Isabelle; and others

    2012-09-15

    The negative polarity rod pinch diode (NPRPD) is a potential millimeter spot size radiography source for high voltage generators (4 to 8 MV) [Cooperstein et al., 'Considerations of rod-pinch diode operation in negative polarity for radiography,' in Proceedings of the 14th IEEE Pulsed Power Conference, 2003, pp. 975-978]. The NPRPD consists of a small diameter (few mm) cylindrical anode extending from the front end of the vacuum cell through a thin annular cathode, held by a central conductor. The polarity has been inverted when compared to the original rod pinch diode [Cooperstein et al., 'Theoretical modeling and experimental characterization of a rod-pinch diode,' Phys. Plasmas 8(10), 4618-4636 (2001)] in order to take advantage from the maximal x-ray emission toward the anode holder at such a voltage [Swanekamp et al., 'Evaluation of self-magnetically pinched diodes up to 10 MV as high resolution flash X-ray sources,' IEEE Trans. Plasma Sci. 32(5), 2004-2016 (2004). We have studied this diode at 4.5 MV, driven by the ASTERIX generator [Raboisson et al., 'ASTERIX, a high intensity X-ray generator,' in Proceedings of the 7th IEEE Pulsed Power Conference, 1989, pp. 567-570.]. This generator, made up of a capacitor bank and a Blumlein line, was initially designed to test the behavior of electronic devices under irradiation. In our experiments, the vacuum diode has been modified in order to set up flash a radiographic diode [Etchessahar et al., 'Negative polarity rod pinch diode experiments on the ASTERIX generator,' in Conference Records-Abstracts, 37th IEEE International Conference on Plasma Science, 2010]. The experiments and numerical simulations presented here allowed the observation and analysis of various physical phenomena associated with the diode operation. Also, the influence of several experimental parameters, such as cathode and anode diameters, materials and surface states, was examined. In order to achieve the most comprehensive characterization of the

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

    PubMed

    Murai, Yuki; Murakami, Ikuya

    2016-09-01

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

  9. Preliminary Study Using Forward Reaction Control System Jets During Space Shuttle Entry

    NASA Technical Reports Server (NTRS)

    Restrepo, Carolina; Valasek, John

    2006-01-01

    Failure or degradation of the flight control system, or hull damage, can lead to loss of vehicle control during entry. Possible failure scenarios are debris impact and wing damage that could result in a large aerodynamic asymmetry which cannot be trimmed out without additional yaw control. Currently the space shuttle uses aerodynamic control surfaces and Reaction Control System jets to control attitude. The forward jets are used for orbital maneuvering only, while the aft jets are used for yaw control during entry. This paper develops a controller for using the forward reaction control system jets as an additional control during entry, and assesses its value and feasibility during failure situations. Forward-aft jet blending logic is created, and implemented on a simplified model of the space shuttle entry flight control system. The model is validated and verified on the nonlinear, six degree-of-freedom Shuttle Engineering Simulator. A rudimentary human factors study was undertaken using the forward cockpit simulator at Johnson Space Center, to assess flying qualities of the new system and pilot workload. Results presented in the paper show that the combination of forward and aft jets provides useful additional yaw control, in addition to potential fuel savings and the ability to balance the use of the fuel in the forward and aft tanks to meet availability constraints of both forward and aft fuel tanks. Piloted simulation studies indicated that using both sets of jets while flying a damaged space shuttle reduces pilot workload, and makes the vehicle more responsive.

  10. Experimental study of turbulence in isothermal jet impingement at intermediate plate spacings

    NASA Astrophysics Data System (ADS)

    Landfried, D. Tyler; Valentino, Alex; Mazumdar, Sagnik; Jana, Anirban; Kimber, Mark

    2013-11-01

    One fundamental problem in fluid dynamics is that of the axisymmetric round flow impinging on a plate placed some distance downstream of the jet. Impinging jets have a rich history of applications including small plate spacings, H/D ~ 1, such as encountered in electronics cooling, or large plate spacings, H/D ~ 102, such as vertical takeoff aircrafts and rocket engines. However, intermediate plate spacings, such as the lower plenum of the next generation nuclear reactors, are not typically studied. In this paper, an experimental study is conducted investigating the effect of the impingement plate on the flow behavior compared to the near free jet behavior when the plate is removed. Using air as the working fluid, a single jet is considered at jet Reynolds numbers of 10000, 20000, and 30000. A three-wire anemometer probe is used to quantify the mean components of velocities as well as the Reynolds stress and the third-order moments in the flow field at various distances between the jet outlet and the impingement plate. When present, the impingement plate is placed a distance of 8, 11, 14, and 17 diameters downstream of the jet. Additionally trends in the kinetic energy and dissipation are investigated for validation with numerical models.

  11. Experimental study of planar opposed jets with acoustic excitation

    NASA Astrophysics Data System (ADS)

    Li, Wei-Feng; Huang, Guo-Feng; Tu, Gong-Yi; Liu, Hai-Feng; Wang, Fu-Chen

    2013-01-01

    Oscillation behaviors of planar opposed jets with acoustic excitation were experimentally investigated. The flow regimes of planar opposed jets at various exit air velocities, nozzle separations, excitation frequencies, and excitation amplitudes have been identified by a flow visualization technique combining with a high-speed camera. Results show that planar opposed jets exhibit horizontal instability at L/H ≤ 4 (where L is the nozzle separation and H is the slit height of the planar nozzle) and deflecting oscillation at L/H ≥ 6. The deflecting oscillation is originally started by the antisymmetric structures in the planar jets and is self-sustained by the periodic changes of the velocity field and the pressure field. At L/H ≤ 4, the acoustic excitation results in the horizontal periodic oscillation, whose frequency is equal to the excitation frequency. The acoustic excitation of oscillation amplitude less than 10% has negligible influence on the deflecting oscillation; for synchronous or asynchronous excitation with higher amplitude, the transition from the deflecting oscillation to a steady state or horizontal oscillation occurs.

  12. Experimental study on the use of synthetic jet actuators for lift control

    NASA Astrophysics Data System (ADS)

    Torres, Ricardo Benjamin

    An experimental study on the use of synthetic jet actuators for lift control is conducted. The synthetic jet actuator is placed on the pressure side towards the trailing edge on a NACA 65(2)-415 airfoil representative of the cross section of an Inlet Guide Vane (IGV) in an industrial gas compressor. By redirecting or vectoring the shear layer at the trailing edge, the synthetic jet actuator increases lift and decreases drag on the airfoil without a mechanical device or flap. A compressor map that defines upper and lower bounds on operating velocities and airfoil dimensions, is compared with operating conditions of the low-speed wind tunnel at San Diego State University, to match gas compressor conditions in the wind tunnel. Realistic test conditions can range from Mach=0.12 to Mach= 0.27 and an airfoil chord from c=0.1 m to c=0.3 m. Based on the operating conditions, a final airfoil model is fabricated with a chord of c=0.1m. Several synthetic jet actuator designs are considered. A initial synthetic jet is designed to house a piezoelectric element with a material frequency of 1200 hz in a cavity with a volume of 4.47 cm3, a slot width of 0.25 mm, and a slot depth of 1.5 mm. With these dimensions, the Helmholtz frequency of the design is 1800Hz. Particle Image Velocimetry (PIV) experiments show that the design has a jet with a peak centerline jet velocity of 26 m/s at 750 Hz. A modified slant face synthetic jet is designed so that the cavity fits flush within the NACA airfoil surface. The slanted synthetic jet has a cavity volume of 4.67 cm3, a slot width of 0.25 mm, and a slot depth of 3.45 mm resulting in a Helmholtz frequency of 1170 hz for this design. PIV experiments show that the jet is redirected along the slant face according to the Coanda effect. A final synthetic jet actuator is directly integrated into the trailing edge of an airfoil with a cavity volume of 4.6 cm3, a slot width of 0.2 mm, and a slot depth of 1.6 mm. The Helmholtz frequency is 1450 Hz and

  13. Statistical Evolution of the Lightning Flash

    NASA Astrophysics Data System (ADS)

    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

  14. Study of cosmic rays and light flashes on board Space Station MIR: the SilEye experiment.

    PubMed

    Bidoli, V; Casolino, M; De Pascale, M P; Furano, G; Morselli, A; Narici, L; Picozza, P; Reali, E; Sparvoli, R; Galper, A M; Ozerov YuV; Popov, A V; Vavilov, N R; Alexandrov, A P; Avdeev, S V; Baturin, Y u; Budarin, Y u; Padalko, G; Shabelnikov, V G; Barbellini, G; Bonvicini, W; Vacchi, A; Zampa, N; Bartalucci, S; Mazzenga, G; Ricci, M; Adriani, O; Spillantini, P; Boezio, M; Carlson, P; Fuglesang, C; Castellini, G; Sannita, W G

    2000-01-01

    The SilEye experiment aims to study the cause and processes related to the anomalous Light Flashes (LF) perceived by astronauts in orbit and their relation with Cosmic Rays. These observations will be also useful in the study of the long duration manned space flight environment. Two PC-driven silicon detector telescopes have been built and placed aboard Space Station MIR. SilEye-1 was launched in 1995 and provided particles track and LF information; the data gathered indicate a linear dependence of FLF(Hz) ( 4 2) 10(3) 5.3 1.7 10(4) Fpart(Hz) if South Atlantic Anomaly fluxes are not included. Even though higher statistic is required, this is an indication that heavy ion interactions with the eye are the main LF cause. To improve quality and quantity of measurements, a second apparatus, SilEye-2, was placed on MIR in 1997, and started work from August 1998. This instrument provides energetic information, which allows nuclear identification in selected energy ranges; we present preliminary measurements of the radiation field inside MIR performed with SilEye-2 detector in June 1998.

  15. Studies of jet fuel additives using the quartz crystal microbalance and pressure monitoring at 140 C

    SciTech Connect

    Zabarnick, S.; Grinstead, R.R.

    1995-05-01

    The quartz crystal microbalance (QCM) and pressure monitoring are used for the evaluation of jet fuel additives for the improvement of jet fuel thermal stability. The mechanisms of additive behavior are determined by measuring the time dependent deposition with the QCM and oxidation by pressure measurements. Studies at various additive concentrations permits the determination of optimum additive concentrations. Additive packages made of mixtures of antioxidants, detergent/dispersants, and metal deactivators are shown to yield good improvements in thermal stability over a wide range of jet fuel types.

  16. Numerical Study of Gamma-Ray Burst Jet Formation in Collapsars

    SciTech Connect

    Nagataki, S.; Takahashi, R.; Mizuta, A.; Takiwaki, T.; /Garching, Max Planck Inst. /Tokyo U.

    2007-06-08

    Two-dimensional MHD simulations are performed using the ZEUS-2D code to investigate the dynamics of a collapsar that generates a GRB jet, taking account of realistic equation of state, neutrino cooling and heating processes, magnetic fields, and gravitational force from the central black hole and self-gravity. It is found that neutrino heating processes are not efficient enough to launch a jet in this study. It is also found that a jet is launched mainly by B{sub {phi}} fields that are amplified by the winding-up effect. However, since the ratio of total energy relative to the rest-mass energy in the jet is not as high as several hundred, we conclude that the jets seen in this study are not GRB jets. This result suggests that general relativistic effects will be important to generating a GRB jet. Also, the accretion disk with magnetic fields may still play an important role in launching a GRB jet, although a simulation for much longer physical time ({approx}10-100 s) is required to confirm this effect. It is shown that a considerable amount of {sup 56}Ni is synthesized in the accretion disk. Thus, there will be a possibility for the accretion disk to supply the sufficient amount of {sup 56}Ni required to explain the luminosity of a hypernova. Also, it is shown that neutron-rich matter due to electron captures with high entropy per baryon is ejected along the polar axis. Thus, there will be a possibility that r-process nucleosynthesis occurs at such a region. Finally, many neutrons will be ejected from the jet, which suggests that signals from the neutron decays may be observed as the delayed bump of the light curve of the afterglow or gamma rays.

  17. DAMAS Processing for a Phased Array Study in the NASA Langley Jet Noise Laboratory

    NASA Technical Reports Server (NTRS)

    Brooks, Thomas F.; Humphreys, William M.; Plassman, Gerald e.

    2010-01-01

    A jet noise measurement study was conducted using a phased microphone array system for a range of jet nozzle configurations and flow conditions. The test effort included convergent and convergent/divergent single flow nozzles, as well as conventional and chevron dual-flow core and fan configurations. Cold jets were tested with and without wind tunnel co-flow, whereas, hot jets were tested only with co-flow. The intent of the measurement effort was to allow evaluation of new phased array technologies for their ability to separate and quantify distributions of jet noise sources. In the present paper, the array post-processing method focused upon is DAMAS (Deconvolution Approach for the Mapping of Acoustic Sources) for the quantitative determination of spatial distributions of noise sources. Jet noise is highly complex with stationary and convecting noise sources, convecting flows that are the sources themselves, and shock-related and screech noise for supersonic flow. The analysis presented in this paper addresses some processing details with DAMAS, for the array positioned at 90 (normal) to the jet. The paper demonstrates the applicability of DAMAS and how it indicates when strong coherence is present. Also, a new approach to calibrating the array focus and position is introduced and demonstrated.

  18. 18-22 cm VLBA Faraday rotation studies of six AGN jets

    NASA Astrophysics Data System (ADS)

    Motter, J. C.; Gabuzda, D. C.

    2017-05-01

    The formation of relativistic jets in active galactic nuclei (AGN) is related to accretion on to their central supermassive black holes, and magnetic fields are believed to play a central role in launching, collimating and accelerating the jet streams from very compact regions out to kiloparsec or megaparsec scales. In the presence of helical or toroidal magnetic fields threading the AGN jets and their immediate vicinity, gradients in the observed Faraday rotation measures are expected due to the systematic change in the line-of-sight component of the magnetic field across the jet. We have analysed total intensity, linear polarization, fractional polarization and Faraday rotation maps based on very long baseline array data obtained at four wavelengths in the 18-22 cm range for six AGN (OJ 287, 3C 279, PKS 1510-089, 3C 345, BL Lac and 3C 454.3). These observations typically probe projected distances out to tens of parsecs from the observed core, and are well suited for Faraday rotation studies due to the relatively long wavelengths used and the similarity of the structures measured at the different wavelengths. We have identified statistically significant, monotonic, transverse Faraday rotation gradients across the jets of four of these six sources, as well as a tentative transverse Faraday rotation gradient across the jet of OJ 287, providing evidence for the presence of toroidal magnetic fields, which may be one component of helical magnetic fields associated with these AGN jets.

  19. Experimental study of elliptical jet from supercritical to subcritical conditions using planar laser induced fluorescence

    NASA Astrophysics Data System (ADS)

    Muthukumaran, C. K.; Vaidyanathan, Aravind

    2015-03-01

    The study of fluid jet dynamics at supercritical conditions involves strong coupling between fluid dynamic and thermodynamic phenomena. Beyond the critical point, the liquid-vapor coexistence ceases to exist, and the fluid exists as a single phase known as supercritical fluid with its properties that are entirely different from liquids and gases. At the critical point, the liquids do not possess surface tension and latent heat of evaporation. Around the critical point, the fluid undergoes large changes in density and possesses thermodynamic anomaly like enhancement in thermal conductivity and specific heat. In the present work, the transition of the supercritical and near-critical elliptical jet into subcritical as well as supercritical environment is investigated experimentally with nitrogen and helium as the surrounding environment. Under atmospheric condition, a liquid jet injected from the elliptical orifice exhibits axis switching phenomena. As the injection temperature increases, the axis switching length also increases. Beyond the critical temperature, the axis switching is not observed. The investigation also revealed that pressure plays a major role in determining the thermodynamic transition of the elliptical jet only for the case of supercritical jet injected into subcritical chamber conditions. At larger pressures, the supercritical jet undergoes disintegration and formation of droplets in the subcritical environment is observed. However, for supercritical jet injection into supercritical environment, the gas-gas like mixing behavior is observed.

  20. Experimental study of elliptical jet from supercritical to subcritical conditions using planar laser induced fluorescence

    SciTech Connect

    Muthukumaran, C. K.; Vaidyanathan, Aravind

    2015-03-15

    The study of fluid jet dynamics at supercritical conditions involves strong coupling between fluid dynamic and thermodynamic phenomena. Beyond the critical point, the liquid-vapor coexistence ceases to exist, and the fluid exists as a single phase known as supercritical fluid with its properties that are entirely different from liquids and gases. At the critical point, the liquids do not possess surface tension and latent heat of evaporation. Around the critical point, the fluid undergoes large changes in density and possesses thermodynamic anomaly like enhancement in thermal conductivity and specific heat. In the present work, the transition of the supercritical and near-critical elliptical jet into subcritical as well as supercritical environment is investigated experimentally with nitrogen and helium as the surrounding environment. Under atmospheric condition, a liquid jet injected from the elliptical orifice exhibits axis switching phenomena. As the injection temperature increases, the axis switching length also increases. Beyond the critical temperature, the axis switching is not observed. The investigation also revealed that pressure plays a major role in determining the thermodynamic transition of the elliptical jet only for the case of supercritical jet injected into subcritical chamber conditions. At larger pressures, the supercritical jet undergoes disintegration and formation of droplets in the subcritical environment is observed. However, for supercritical jet injection into supercritical environment, the gas-gas like mixing behavior is observed.

  1. Studying the Dynamics of Non-stationary Jet Streams Formation in the Northern Hemisphere Troposphere

    NASA Astrophysics Data System (ADS)

    Emtsev, Sergey; Krasouski, Aliaksandr; Svetashev, Alexander; Turishev, Leonid; Barodka, Siarhei

    2015-04-01

    In the present study, we investigate dynamics of non-stationary jets formation in troposphere by means of mesoscale simulations in the Weather Research & Forecasting (WRF) modeling system, analyzing jet streams that affected the territory of Belarus over the time period of 2010-2012. For that purpose, we perform modeling on domains with 5 km, 3 km and 1 km grid steps and 35 vertical coordinate levels with an upper boundary of 10 hPa. We focus our attention to identification of basic regularities in formation, movements and transformations of jet streams, as well as to analysis of their characteristic features, geographical position and underlying atmospheric processes and their classification. On the basis of these regularities, we define basic meteorological parameters that can be used to directly or indirectly (as well as qualitatively and quantitatively) identify the presence of jet streams in the specific region of troposphere, and also to determine their localization, stage of development and other characteristics. Furthermore, we estimate energetic parameters of the identified jet streams and their impact on synoptic situation in the surrounding region. Analyzing meteorological fields obtained from satellite observations, we elaborate a methodology of operational detection and localization of non-stationary jet streams from satellite data. Validation of WRF modeling results with these data proves that mesoscale simulations with WRF are able to provide quite successful forecasts of non-stationary tropospheric jet streams occurrence and also determination of their localization and main characteristics up to 3 days in advance.

  2. Hot Flashes and Carotid Intima Media Thickness among Midlife Women

    PubMed Central

    Thurston, Rebecca C.; Sutton-Tyrrell, Kim; Everson-Rose, Susan A.; Hess, Rachel; Powell, Lynda H.; Matthews, Karen A.

    2010-01-01

    Objective Emerging evidence suggests associations between menopausal hot flashes and cardiovascular risk. Whether hot flashes are associated with intima media thickness (IMT) or IMT changes over time is unknown. We hypothesized that reported hot flashes would be associated with greater IMT cross-sectionally and with greater IMT progression over two years. Methods Participants were 432 women ages 45-58 at baseline participating in SWAN Heart, an ancillary study to the Study of Women's Health Across the Nation. Measures at the SWAN Heart baseline and follow-up visit two years later included a carotid artery ultrasound, reported hot flashes (past two weeks: none, 1-5, ≥6 days), and a blood sample for measurement of estradiol. Results Women reporting hot flashes ≥6 days in the prior two weeks had significantly higher IMT than women without hot flashes at baseline (mean difference(SE), mm =0.02(0.01), p=0.03) and follow-up (mean difference(SE), mm =0.02(0.01), p=0.04) visits, controlling for demographic factors and cardiovascular risk factors. Reporting hot flashes at both study visits was associated with higher follow-up IMT relative to reporting hot flashes at neither visit (mean difference(SE), mm=0.03(0.01), p=0.03). Associations between hot flashes and IMT largely remained after adjusting for estradiol. An interaction between hot flashes and obesity status was observed (p=0.05) such that relations between hot flashes and IMT were observed principally among overweight/obese women. Hot flashes were not associated with IMT progression. Conclusions These findings provided some indication that women reporting hot flashes ≥6 days in the prior two weeks may have higher IMT than women without hot flashes, particularly for women who are overweight or obese. Further work should determine whether hot flashes mark adverse underlying vascular changes. PMID:21242820

  3. Risk factors for hot flashes in midlife women.

    PubMed

    Whiteman, Maura K; Staropoli, Catherine A; Benedict, Jamie C; Borgeest, Christina; Flaws, Jodi A

    2003-06-01

    To review the scientific literature pertaining to potential risk factors for hot flashes in midlife women. Scientific publications reporting on risk factors for hot flashes were identified through a systematic Medline search and are summarized in this review paper. Although few studies have investigated risk factors for hot flashes in midlife women, consistent evidence suggests that smoking is associated with an increased risk for hot flashes. In addition, some studies suggest that other factors, such as hormone levels, body size, tubal ligation, surgical menopause, and race/ethnicity, may be associated with the occurrence of hot flashes. Future studies are needed to confirm previous findings and to identify additional risk factors for hot flashes. Such studies will increase our understanding of the etiology of hot flashes and may lead to better treatments and preventive measures for this condition.

  4. Study on volatility and flash point of the pseudo-binary mixtures of sunflowerseed-based biodiesel+ethanol.

    PubMed

    Guo, Yongsheng; Wei, Hui; Yang, Fengjun; Li, Dan; Fang, Wenjun; Lin, Ruisen

    2009-08-15

    Volatility and flash point for the pseudo-binary mixtures of sunflower seed-based biodiesel+ethanol were measured over the entire composition range. The biodiesel was prepared by the transesterification of sunflower seed oil in supercritical methanol without using any catalyst. The vapor pressures of mixtures of biodiesel+ethanol as a function of temperature were measured by comparative ebulliometry with an inclined ebulliometer. The vapor pressures versus composition at different temperatures and temperatures versus composition at different pressures were obtained from Antoine correlations. It is found that ethanol can adjust effectively the volatility and flash point of the biodiesel. The correlation of the flash points with the vapor pressure data for the pseudo-binary mixtures of biodiesel+ethanol displays agreement with the experimental data obtained by closed cup test.

  5. Sensitivity of quantitative precipitation forecasts to boundary layer parameterization: a flash flood case study in the Western Mediterranean

    NASA Astrophysics Data System (ADS)

    Zampieri, M.; Malguzzi, P.; Buzzi, A.

    2005-08-01

    The "Montserrat-2000" severe flash flood event which occurred over Catalonia on 9 and 10 June 2000 is analyzed. Strong precipitation was generated by a mesoscale convective system associated with the development of a cyclone. The location of heavy precipitation depends on the position of the cyclone, which, in turn, is found to be very sensitive to various model characteristics and initial conditions. Numerical simulations of this case study using the hydrostatic BOLAM and the non-hydrostatic MOLOCH models are performed in order to test the effects of different formulations of the boundary layer parameterization: a modified version of the Louis (order 1) model and a custom version of the E-ℓ (order 1.5) model. Both of them require a diagnostic formulation of the mixing length, but the use of the turbulent kinetic energy equation in the E-ℓ model allows to represent turbulence history and non-locality effects and to formulate a more physically based mixing length. The impact of the two schemes is different in the two models. The hydrostatic model, run at 1/5 degree resolution, is less sensitive, but the quantitative precipitation forecast is in any case unsatisfactory in terms of localization and amount. Conversely, the non-hydrostatic model, run at 1/50 degree resolution, is capable of realistically simulate timing, position and amount of precipitation, with the apparently superior results obtained with the E-ℓ parameterization model.

  6. Gating Kinetics of the Cyclic-GMP-Activated Channel of Retinal Rods: Flash Photolysis and Voltage-Jump Studies

    NASA Astrophysics Data System (ADS)

    Karpen, Jeffrey W.; Zimmerman, Anita L.; Stryer, Lubert; Baylor, Denis A.

    1988-02-01

    The gating kinetics of the cGMP-activated cation channel of salamander retinal rods have been studied in excised membrane patches. Relaxations in patch current were observed after two kinds of perturbation: (i) fast jumps of cGMP concentration, generated by laser flash photolysis of a cGMP ester (``caged'' cGMP), and (ii) membrane voltage jumps, which perturb activation of the channel by cGMP. In both methods the speed of activation increased with the final cGMP concentration. The results are explained by a simple kinetic model in which activation involves three sequential cGMP binding steps with bimolecular rate constants close to the diffusion-controlled limit; fully liganded channels undergo rapid open-closed transitions. Voltage perturbs activation by changing the rate constant for channel closing, which increases with hyperpolarization. Intramolecular transitions of the fully liganded channel limit the kinetics of activation at high cGMP concentrations (>50 μ M), whereas at physiological cGMP concentrations (<5 μ M), the kinetics of activation are limited by the third cGMP binding step. The channel appears to be optimized for rapid responses to changes in cytoplasmic cGMP concentration.

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

    PubMed

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

    2014-01-01

    The kinetics of transients formed under photoexcitation of benzophenone (B) dissolved in three different polymers was studied by ns laser flash photolysis. These polymers were the soft rubbers poly (ethylene-co-butylene) (EB), polystyrene block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) and hard polystyrene (PS). We monitored the decay kinetics of triplet state (3)B(*) and of ketyl radicals BH(●). We observed exponential decay of (3)B(*) and two-stage decay kinetics of BH(●) in EB. The first stage is a fast cage recombination of a radical pair (BH(●), radical of polymer R(●)). The second slow stage of BH(●) decay follows the second-order law with a relatively high rate constant, which corresponds to recombination of BH(●) in a homogeneous liquid with a viscosity of only ~0.1 P (about five times of 2-propanol viscosity). Application of a magnetic field (MF) of 0.2 T leads to deceleration of both stages of BH(●) decay in EB by approximately 20%. Decay kinetics of both transients were observed in SEBS. There was no MF effect on BH(●) decay in SEBS. We only observed (3)B(*) in PS. Decay kinetics of (3)B(*) in this case were described as polychromatic dispersive first-order kinetics. We discuss the effects of polymer structure on transient kinetics and the MF effect. © 2013 The American Society of Photobiology.

  8. Analytic and Monte Carlo studies of jets with heavy mesons and quarkonia

    SciTech Connect

    Bain, Reggie; Dai, Lin; Hornig, Andrew; Leibovich, Adam K.; Makris, Yiannis; Mehen, Thomas

    2016-06-21

    Here, we study jets with identified hadrons in which a family of jet-shape variables called angularities are measured, extending the concept of fragmenting jet functions (FJFs) to these observables. FJFs determine the fraction of energy, z, carried by an identified hadron in a jet with angularity, τa. The FJFs are convolutions of fragmentation functions (FFs), evolved to the jet energy scale, with perturbatively calculable matching coefficients. Renormalization group equations are used to provide resummed calculations with next-to-leading logarithm prime (NLL’) accuracy. We apply this formalism to two-jet events in e+e collisions with B mesons in the jets, and three-jet events in which a J/ψ is produced in the gluon jet. In the case of B mesons, we use a phenomenological FF extracted from e+e collisions at the Z0 pole evaluated at the scale μ = mb. For events with J/ψ, the FF can be evaluated in terms of Non-Relativistic QCD (NRQCD) matrix elements at the scale μ = 2mc. The z and τa distributions from our NLL’ calculations are compared with predictions from monte carlo event generators. While we find consistency between the predictions for B mesons and the J/ψ distributions in τa, we find the z distributions for J/ψ differ significantly. We describe an attempt to merge PYTHIA showers with NRQCD FFs that gives good agreement with NLL’ calculations of the z distributions.

  9. Experimental study of jet gas-particle interaction generated during explosive volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Medici, E. F.; Waite, G. P.

    2014-12-01

    During violent volcanic eruptions, a shock wave may be generated that is immediately followed by the formation of a supersonic jet. The overpressurized vapor-solid-liquid mixture being ejected begins to expand and accelerate. Oblique shock waves and rarefaction waves are generated at the edge of the crater. The oblique shock waves, inclined relatively to the flow axis, intersect forming a structure called a "Mach disk" or "Mach diamond". This pattern repeats until the jet decelerates into subsonic flow. In an explosive volcanic eruption, unlike other applications involving jets, a mixture of hot gas and solid particles is present. The mixture typically contains a relatively high percentage of solid particles of different sizes. The relationship between jet and particle is one the major parameters affecting the formation of ash plume dynamics and the pyroclastic flows. Therefore, a more comprehensive study is needed in order to understand the mixing occurring within the volcanic eruption jet, specifically, the effect of particle size and concentration. In this work, a series of analog explosive volcanic experiments using an atmospheric shock tube are performed to generate supersonic jets. High-speed video imaging of the expanding jet as well as the pressure evolution at different points in space are recorded for different values of initial energy and particle sizes and concentrations. Particles of different sizes and in various concentrations are placed inside the jet stream in which all the environmental conditions are monitored. Understanding of the coupling between the particles and the jet dynamics interaction is the first step toward a more thorough understanding of ash plume dynamics and the pyroclastic flows formation.

  10. Analytic and Monte Carlo studies of jets with heavy mesons and quarkonia

    DOE PAGES

    Bain, Reggie; Dai, Lin; Hornig, Andrew; ...

    2016-06-21

    Here, we study jets with identified hadrons in which a family of jet-shape variables called angularities are measured, extending the concept of fragmenting jet functions (FJFs) to these observables. FJFs determine the fraction of energy, z, carried by an identified hadron in a jet with angularity, τa. The FJFs are convolutions of fragmentation functions (FFs), evolved to the jet energy scale, with perturbatively calculable matching coefficients. Renormalization group equations are used to provide resummed calculations with next-to-leading logarithm prime (NLL’) accuracy. We apply this formalism to two-jet events in e+e– collisions with B mesons in the jets, and three-jet eventsmore » in which a J/ψ is produced in the gluon jet. In the case of B mesons, we use a phenomenological FF extracted from e+e– collisions at the Z0 pole evaluated at the scale μ = mb. For events with J/ψ, the FF can be evaluated in terms of Non-Relativistic QCD (NRQCD) matrix elements at the scale μ = 2mc. The z and τa distributions from our NLL’ calculations are compared with predictions from monte carlo event generators. While we find consistency between the predictions for B mesons and the J/ψ distributions in τa, we find the z distributions for J/ψ differ significantly. We describe an attempt to merge PYTHIA showers with NRQCD FFs that gives good agreement with NLL’ calculations of the z distributions.« less

  11. Lightning flash characteristics, 1987

    SciTech Connect

    Orville, R.E.; Henderson, R.W.; Pyle, R.B.

    1989-08-01

    A magnetic direction finding system for the detection of lightning flashes to ground has operated in the eastern part of the United States since 1982 and has now expanded to cover over 80 percent of the contiguous United States. Complete coverage is planned for the end of 1988. Time, location, flash polarity, multiplicity (the number of strokes per flash) and the initial peak magnetic radiation field amplitude are recorded in real time. Flash locations, time, polarity, peak current, and multiplicity are displayed routinely for research and operational uses. New results for 1987 include the flash density for strikes to ground in the peak current ranges 0--35 kA, 35--65 kA, 65--100 kA and greater than 100 kA. The lightning information is available to utilities through a satellite communication link for real time access or by phone lines for access to historical data, where the last five million flashes are available. The flash information is being compiled into a data base to provide statistical information necessary for the prediction of the surge performance of electric power lines and the improvement of surge protection practices. Results for the year 1987 are presented in this report. 13 refs., 25 figs.

  12. A Study of the Unstable Modes in High Mach Number Gaseous Jets and Shear Layers

    NASA Astrophysics Data System (ADS)

    Bassett, Gene Marcel

    1993-01-01

    Instabilities affecting the propagation of supersonic gaseous jets have been studied using high resolution computer simulations with the Piecewise-Parabolic-Method (PPM). These results are discussed in relation to jets from galactic nuclei. These studies involve a detailed treatment of a single section of a very long jet, approximating the dynamics by using periodic boundary conditions. Shear layer simulations have explored the effects of shear layers on the growth of nonlinear instabilities. Convergence of the numerical approximations has been tested by comparing jet simulations with different grid resolutions. The effects of initial conditions and geometry on the dominant disruptive instabilities have also been explored. Simulations of shear layers with a variety of thicknesses, Mach numbers and densities perturbed by incident sound waves imply that the time for the excited kink modes to grow large in amplitude and disrupt the shear layer is taug = (546 +/- 24) (M/4)^{1.7 } (Apert/0.02) ^{-0.4} delta/c, where M is the jet Mach number, delta is the half-width of the shear layer, and A_ {pert} is the perturbation amplitude. For simulations of periodic jets, the initial velocity perturbations set up zig-zag shock patterns inside the jet. In each case a single zig-zag shock pattern (an odd mode) or a double zig-zag shock pattern (an even mode) grows to dominate the flow. The dominant kink instability responsible for these shock patterns moves approximately at the linear resonance velocity, nu_ {mode} = cextnu_ {relative}/(cjet + c_ {ext}). For high resolution simulations (those with 150 or more computational zones across the jet width), the even mode dominates if the even penetration is higher in amplitude initially than the odd perturbation. For low resolution simulations, the odd mode dominates even for a stronger even mode perturbation. In high resolution simulations the jet boundary rolls up and large amounts of external gas are entrained into the jet. In low

  13. Studies of inclusive four-jet production with two b -tagged jets in proton-proton collisions at 7 TeV

    DOE PAGES

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; ...

    2016-12-08

    Here, measurements are presented of the cross section for the production of at least four jets, of which at least two originate from b quarks, in proton-proton collisions. Data collected with the CMS detector at the LHC at a center-of-mass energy of 7 TeV are used, corresponding to an integrated luminosity of 3 pb-1. The cross section is measured as a function of the jet transverse momentum for pT > 20 GeV, and of the jet pseudorapidity for |η| < 2.4 (b jets), 4.7 (untagged jets). The correlations in azimuthal angle and pT between the jets are also studied. The inclusivemore » cross section is measured to be σ(pp → 2b + 2j + X) = 69 ± 3(stat) ± 24(syst) nb. The η and pT distributions of the four jets and the correlations between them are well reproduced by event generators that combine perturbative QCD calculations at next-to-leading-order accuracy with contributions from parton showers and multiparton interactions.« less

  14. Studies of inclusive four-jet production with two b -tagged jets in proton-proton collisions at 7 TeV

    NASA Astrophysics Data System (ADS)

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; König, A.; Krätschmer, I.; Liko, D.; Matsushita, T.; Mikulec, I.; Rabady, D.; Rad, N.; Rahbaran, B.; Rohringer, H.; Schieck, J.; Strauss, J.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; De Wolf, E. A.; Janssen, X.; Lauwers, J.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; Daci, N.; De Bruyn, I.; Deroover, K.; Heracleous, N.; Lowette, S.; Moortgat, S.; Moreels, L.; Olbrechts, A.; Python, Q.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Parijs, I.; Brun, H.; Caillol, C.; Clerbaux, B.; De Lentdecker, G.; Delannoy, H.; Fasanella, G.; Favart, L.; Goldouzian, R.; Grebenyuk, A.; Karapostoli, G.; Lenzi, T.; Léonard, A.; Luetic, J.; Maerschalk, T.; Marinov, A.; Randle-conde, A.; Seva, T.; Vander Velde, C.; Vanlaer, P.; Yonamine, R.; Zenoni, F.; Zhang, F.; Cimmino, A.; Cornelis, T.; Dobur, D.; Fagot, A.; Garcia, G.; Gul, M.; Poyraz, D.; Salva, S.; Schöfbeck, R.; Tytgat, M.; Van Driessche, W.; Yazgan, E.; Zaganidis, N.; Bakhshiansohi, H.; Beluffi, C.; Bondu, O.; Brochet, S.; Bruno, G.; Caudron, A.; Ceard, L.; De Visscher, S.; Delaere, C.; Delcourt, M.; Forthomme, L.; Francois, B.; Giammanco, A.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Magitteri, A.; Mertens, A.; Musich, M.; Nuttens, C.; Piotrzkowski, K.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Wertz, S.; Beliy, N.; Aldá Júnior, W. L.; Alves, F. L.; Alves, G. A.; Brito, L.; Hensel, C.; Moraes, A.; Pol, M. E.; Rebello Teles, P.; Belchior Batista Das Chagas, E.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; Da Silveira, G. G.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Huertas Guativa, L. M.; Malbouisson, H.; Matos Figueiredo, D.; Mora Herrera, C.; Mundim, L.; Nogima, H.; Prado Da Silva, W. L.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Ahuja, S.; Bernardes, C. A.; Dogra, S.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Moon, C. S.; Novaes, S. F.; Padula, Sandra S.; Romero Abad, D.; Ruiz Vargas, J. C.; Aleksandrov, A.; Hadjiiska, R.; Iaydjiev, P.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Fang, W.; Ahmad, M.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Chen, Y.; Cheng, T.; Jiang, C. H.; Leggat, D.; Liu, Z.; Romeo, F.; Shaheen, S. M.; Spiezia, A.; Tao, J.; Wang, C.; Wang, Z.; Zhang, H.; Zhao, J.; Ban, Y.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; González Hernández, C. F.; Ruiz Alvarez, J. D.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Puljak, I.; Ribeiro Cipriano, P. M.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Ferencek, D.; Kadija, K.; Micanovic, S.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Finger, M.; Finger, M.; Carrera Jarrin, E.; Abdelalim, A. A.; El-khateeb, E.; Mahmoud, M. A.; Radi, A.; Calpas, B.; Kadastik, M.; Murumaa, M.; Perrini, L.; Raidal, M.; Tiko, A.; Veelken, C.; Eerola, P.; Pekkanen, J.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Peltola, T.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Ghosh, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Kucher, I.; Locci, E.; Machet, M.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Zghiche, A.; Abdulsalam, A.; Antropov, I.; Baffioni, S.; Beaudette, F.; Busson, P.; Cadamuro, L.; Chapon, E.; Charlot, C.; Davignon, O.; Granier de Cassagnac, R.; Jo, M.; Lisniak, S.; Miné, P.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Pigard, P.; Regnard, S.; Salerno, R.; Sirois, Y.; Strebler, T.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Buttignol, M.; Chabert, E. C.; Chanon, N.; Collard, C.; Conte, E.; Coubez, X.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Le Bihan, A.-C.; Merlin, J. A.; Skovpen, K.; Van Hove, P.; Gadrat, S.; Beauceron, S.; Bernet, C.; Boudoul, G.; Bouvier, E.; Carrillo Montoya, C. A.; Chierici, R.; Contardo, D.; Courbon, B.; Depasse, P.; El Mamouni, H.; Fan, J.; Fay, J.; Gascon, S.; Gouzevitch, M.; Grenier, G.; Ille, B.; Lagarde, F.; Laktineh, I. B.; Lethuillier, M.; Mirabito, L.; Pequegnot, A. L.; Perries, S.; Popov, A.; Sabes, D.; Sordini, V.; Vander Donckt, M.; Verdier, P.; Viret, S.; Toriashvili, T.; Tsamalaidze, Z.; Autermann, C.; Beranek, S.; Feld, L.; Heister, A.; Kiesel, M. K.; Klein, K.; Lipinski, M.; Ostapchuk, A.; Preuten, M.; Raupach, F.; Schael, S.; Schomakers, C.; Schulte, J. F.; Schulz, J.; Verlage, T.; Weber, H.; Zhukov, V.; Brodski, M.; Dietz-Laursonn, E.; Duchardt, D.; Endres, M.; Erdmann, M.; Erdweg, S.; Esch, T.; Fischer, R.; Güth, A.; Hebbeker, T.; Heidemann, C.; Hoepfner, K.; Knutzen, S.; Merschmeyer, M.; Meyer, A.; Millet, P.; Mukherjee, S.; Olschewski, M.; Padeken, K.; Papacz, P.; Pook, T.; Radziej, M.; Reithler, H.; Rieger, M.; Scheuch, F.; Sonnenschein, L.; Teyssier, D.; Thüer, S.; Cherepanov, V.; Erdogan, Y.; Flügge, G.; Haj Ahmad, W.; Hoehle, F.; Kargoll, B.; Kress, T.; Künsken, A.; Lingemann, J.; Nehrkorn, A.; Nowack, A.; Nugent, I. M.; Pistone, C.; Pooth, O.; Stahl, A.; Aldaya Martin, M.; Asawatangtrakuldee, C.; Asin, I.; Beernaert, K.; Behnke, O.; Behrens, U.; Bin Anuar, A. A.; Borras, K.; Campbell, A.; Connor, P.; Contreras-Campana, C.; Costanza, F.; Diez Pardos, C.; Dolinska, G.; Eckerlin, G.; Eckstein, D.; Gallo, E.; Garay Garcia, J.; Geiser, A.; Gizhko, A.; Grados Luyando, J. M.; Gunnellini, P.; Harb, A.; Hauk, J.; Hempel, M.; Jung, H.; Kalogeropoulos, A.; Karacheban, O.; Kasemann, M.; Keaveney, J.; Kieseler, J.; Kleinwort, C.; Korol, I.; Lange, W.; Lelek, A.; Leonard, J.; Lipka, K.; Lobanov, A.; Lohmann, W.; Mankel, R.; Melzer-Pellmann, I.-A.; Meyer, A. B.; Mittag, G.; Mnich, J.; Mussgiller, A.; Ntomari, E.; Pitzl, D.; Placakyte, R.; Raspereza, A.; Roland, B.; Sahin, M. Ö.; Saxena, P.; Schoerner-Sadenius, T.; Seitz, C.; Spannagel, S.; Stefaniuk, N.; Trippkewitz, K. D.; Van Onsem, G. P.; Walsh, R.; Wissing, C.; Blobel, V.; Centis Vignali, M.; Draeger, A. R.; Dreyer, T.; Garutti, E.; Goebel, K.; Gonzalez, D.; Haller, J.; Hoffmann, M.; Junkes, A.; Klanner, R.; Kogler, R.; Kovalchuk, N.; Lapsien, T.; Lenz, T.; Marchesini, I.; Marconi, D.; Meyer, M.; Niedziela, M.; Nowatschin, D.; Ott, J.; Pantaleo, F.; Peiffer, T.; Perieanu, A.; Poehlsen, J.; Sander, C.; Scharf, C.; Schleper, P.; Schmidt, A.; Schumann, S.; Schwandt, J.; Stadie, H.; Steinbrück, G.; Stober, F. M.; Stöver, M.; Tholen, H.; Troendle, D.; Usai, E.; Vanelderen, L.; Vanhoefer, A.; Vormwald, B.; Barth, C.; Baus, C.; Berger, J.; Butz, E.; Chwalek, T.; Colombo, F.; De Boer, W.; Dierlamm, A.; Fink, S.; Friese, R.; Giffels, M.; Gilbert, A.; Haitz, D.; Hartmann, F.; Heindl, S. M.; Husemann, U.; Katkov, I.; Lobelle Pardo, P.; Maier, B.; Mildner, H.; Mozer, M. U.; Müller, T.; Müller, Th.; Plagge, M.; Quast, G.; Rabbertz, K.; Röcker, S.; Roscher, F.; Schröder, M.; Sieber, G.; Simonis, H. J.; Ulrich, R.; Wagner-Kuhr, J.; Wayand, S.; Weber, M.; Weiler, T.; Williamson, S.; Wöhrmann, C.; Wolf, R.; Anagnostou, G.; Daskalakis, G.; Geralis, T.; Giakoumopoulou, V. A.; Kyriakis, A.; Loukas, D.; Topsis-Giotis, I.; Agapitos, A.; Kesisoglou, S.; Panagiotou, A.; Saoulidou, N.; Tziaferi, E.; Evangelou, I.; Flouris, G.; Foudas, C.; Kokkas, P.; Loukas, N.; Manthos, N.; Papadopoulos, I.; Paradas, E.; Filipovic, N.; Bencze, G.; Hajdu, C.; Hidas, P.; Horvath, D.; Sikler, F.; Veszpremi, V.; Vesztergombi, G.; Zsigmond, A. J.; Beni, N.; Czellar, S.; Karancsi, J.; Makovec, A.; Molnar, J.; Szillasi, Z.; Bartók, M.; Raics, P.; Trocsanyi, Z. L.; Ujvari, B.; Bahinipati, S.; Choudhury, S.; Mal, P.; Mandal, K.; Nayak, A.; Sahoo, D. K.; Sahoo, N.; Swain, S. K.; Bansal, S.; Beri, S. B.; Bhatnagar, V.; Chawla, R.; Bhawandeep, U.; Kalsi, A. K.; Kaur, A.; Kaur, M.; Kumar, R.; Mehta, A.; Mittal, M.; Singh, J. B.; Walia, G.; Kumar, Ashok; Bhardwaj, A.; Choudhary, B. C.; Garg, R. B.; Keshri, S.; Kumar, A.; Malhotra, S.; Naimuddin, M.; Nishu, N.; Ranjan, K.; Sharma, R.; Sharma, V.; Bhattacharya, R.; Bhattacharya, S.; Chatterjee, K.; Dey, S.; Dutt, S.; Dutta, S.; Ghosh, S.; Majumdar, N.; Modak, A.; Mondal, K.; Mukhopadhyay, S.; Nandan, S.; Purohit, A.; Roy, A.; Roy, D.; Roy Chowdhury, S.; Sarkar, S.; Sharan, M.; Thakur, S.; Behera, P. K.; Chudasama, R.; Dutta, D.; Jha, V.; Kumar, V.; Mohanty, A. K.; Netrakanti, P. K.; Pant, L. M.; Shukla, P.; Topkar, A.; Aziz, T.; Dugad, S.; Kole, G.; Mahakud, B.; Mitra, S.; Mohanty, G. B.; Sur, N.; Sutar, B.; Banerjee, S.; Bhowmik, S.; Dewanjee, R. K.; Ganguly, S.; Guchait, M.; Jain, Sa.; Kumar, S.; Maity, M.; Majumder, G.; Mazumdar, K.; Parida, B.; Sarkar, T.; Wickramage, N.; Chauhan, S.; Dube, S.; Kapoor, A.; Kothekar, K.; Rane, A.; Sharma, S.; Behnamian, H.; Chenarani, S.; Eskandari Tadavani, E.; Etesami, S. M.; Fahim, A.; Khakzad, M.; Mohammadi Najafabadi, M.; Naseri, M.; Paktinat Mehdiabadi, S.; Rezaei Hosseinabadi, F.; Safarzadeh, B.; Zeinali, M.; Felcini, M.; Grunewald, M.; Abbrescia, M.; Calabria, C.; Caputo, C.; Colaleo, A.; Creanza, D.; Cristella, L.; De Filippis, N.; De Palma, M.; Fiore, L.; Iaselli, G.; Maggi, G.; Maggi, M.; Miniello, G.; My, S.; Nuzzo, S.; Pompili, A.; Pugliese, G.; Radogna, R.; Ranieri, A.; Selvaggi, G.; Silvestris, L.; Venditti, R.; Verwilligen, P.; Abbiendi, G.; Battilana, C.; Bonacorsi, D.; Braibant-Giacomelli, S.; Brigliadori, L.; Campanini, R.; Capiluppi, P.; Castro, A.; Cavallo, F. R.; Chhibra, S. S.; Codispoti, G.; Cuffiani, M.; Dallavalle, G. M.; Fabbri, F.; Fanfani, A.; Fasanella, D.; Giacomelli, P.; Grandi, C.; Guiducci, L.; Marcellini, S.; Masetti, G.; Montanari, A.; Navarria, F. L.; Perrotta, A.; Rossi, A. M.; Rovelli, T.; Siroli, G. P.; Tosi, N.; Albergo, S.; Chiorboli, M.; Costa, S.; Di Mattia, A.; Giordano, F.; Potenza, R.; Tricomi, A.; Tuve, C.; Barbagli, G.; Ciulli, V.; Civinini, C.; D'Alessandro, R.; Focardi, E.; Gori, V.; Lenzi, P.; Meschini, M.; Paoletti, S.; Sguazzoni, G.; Viliani, L.; Benussi, L.; Bianco, S.; Fabbri, F.; Piccolo, D.; Primavera, F.; Calvelli, V.; Ferro, F.; Lo Vetere, M.; Monge, M. R.; Robutti, E.; Tosi, S.; Brianza, L.; Dinardo, M. E.; Fiorendi, S.; Gennai, S.; Ghezzi, A.; Govoni, P.; Malvezzi, S.; Manzoni, R. A.; Marzocchi, B.; Menasce, D.; Moroni, L.; Paganoni, M.; Pedrini, D.; Pigazzini, S.; Ragazzi, S.; Tabarelli de Fatis, T.; Buontempo, S.; Cavallo, N.; De Nardo, G.; Di Guida, S.; Esposito, M.; Fabozzi, F.; Iorio, A. O. M.; Lanza, G.; Lista, L.; Meola, S.; Paolucci, P.; Sciacca, C.; Thyssen, F.; Azzi, P.; Bacchetta, N.; Benato, L.; Bisello, D.; Boletti, A.; Carlin, R.; Carvalho Antunes De Oliveira, A.; Checchia, P.; Dall'Osso, M.; De Castro Manzano, P.; Dorigo, T.; Dosselli, U.; Gasparini, F.; Gasparini, U.; Gozzelino, A.; Lacaprara, S.; Margoni, M.; Meneguzzo, A. T.; Pazzini, J.; Pozzobon, N.; Ronchese, P.; Simonetto, F.; Torassa, E.; Zanetti, M.; Zotto, P.; Zucchetta, A.; Zumerle, G.; Braghieri, A.; Magnani, A.; Montagna, P.; Ratti, S. P.; Re, V.; Riccardi, C.; Salvini, P.; Vai, I.; Vitulo, P.; Alunni Solestizi, L.; Bilei, G. M.; Ciangottini, D.; Fanò, L.; Lariccia, P.; Leonardi, R.; Mantovani, G.; Menichelli, M.; Saha, A.; Santocchia, A.; Androsov, K.; Azzurri, P.; Bagliesi, G.; Bernardini, J.; Boccali, T.; Castaldi, R.; Ciocci, M. A.; Dell'Orso, R.; Donato, S.; Fedi, G.; Giassi, A.; Grippo, M. 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W.; Wyslouch, B.; Yang, M.; Zhukova, V.; Benvenuti, A. C.; Chatterjee, R. M.; Evans, A.; Finkel, A.; Gude, A.; Hansen, P.; Kalafut, S.; Kao, S. C.; Kubota, Y.; Lesko, Z.; Mans, J.; Nourbakhsh, S.; Ruckstuhl, N.; Rusack, R.; Tambe, N.; Turkewitz, J.; Acosta, J. G.; Oliveros, S.; Avdeeva, E.; Bartek, R.; Bloom, K.; Bose, S.; Claes, D. R.; Dominguez, A.; Fangmeier, C.; Gonzalez Suarez, R.; Kamalieddin, R.; Knowlton, D.; Kravchenko, I.; Malta Rodrigues, A.; Meier, F.; Monroy, J.; Siado, J. E.; Snow, G. R.; Stieger, B.; Alyari, M.; Dolen, J.; George, J.; Godshalk, A.; Harrington, C.; Iashvili, I.; Kaisen, J.; Kharchilava, A.; Kumar, A.; Parker, A.; Rappoccio, S.; Roozbahani, B.; Alverson, G.; Barberis, E.; Baumgartel, D.; Hortiangtham, A.; Massironi, A.; Morse, D. M.; Nash, D.; Orimoto, T.; Teixeira De Lima, R.; Trocino, D.; Wang, R.-J.; Wood, D.; Bhattacharya, S.; Hahn, K. A.; Kubik, A.; Low, J. F.; Mucia, N.; Odell, N.; Pollack, B.; Schmitt, M. H.; Sung, K.; Trovato, M.; Velasco, M.; Dev, N.; Hildreth, M.; Hurtado Anampa, K.; Jessop, C.; Karmgard, D. J.; Kellams, N.; Lannon, K.; Marinelli, N.; Meng, F.; Mueller, C.; Musienko, Y.; Planer, M.; Reinsvold, A.; Ruchti, R.; Smith, G.; Taroni, S.; Valls, N.; Wayne, M.; Wolf, M.; Woodard, A.; Alimena, J.; Antonelli, L.; Brinson, J.; Bylsma, B.; Durkin, L. S.; Flowers, S.; Francis, B.; Hart, A.; Hill, C.; Hughes, R.; Ji, W.; Liu, B.; Luo, W.; Puigh, D.; Winer, B. L.; Wulsin, H. W.; Cooperstein, S.; Driga, O.; Elmer, P.; Hardenbrook, J.; Hebda, P.; Luo, J.; Marlow, D.; Medvedeva, T.; Mooney, M.; Olsen, J.; Palmer, C.; Piroué, P.; Stickland, D.; Tully, C.; Zuranski, A.; Malik, S.; Barker, A.; Barnes, V. E.; Benedetti, D.; Folgueras, S.; Gutay, L.; Jha, M. K.; Jones, M.; Jung, A. W.; Jung, K.; Miller, D. H.; Neumeister, N.; Radburn-Smith, B. C.; Shi, X.; Sun, J.; Svyatkovskiy, A.; Wang, F.; Xie, W.; Xu, L.; Parashar, N.; Stupak, J.; Adair, A.; Akgun, B.; Chen, Z.; Ecklund, K. M.; Geurts, F. J. M.; Guilbaud, M.; Li, W.; Michlin, B.; Northup, M.; Padley, B. P.; Redjimi, R.; Roberts, J.; Rorie, J.; Tu, Z.; Zabel, J.; Betchart, B.; Bodek, A.; de Barbaro, P.; Demina, R.; Duh, Y. t.; Ferbel, T.; Galanti, M.; Garcia-Bellido, A.; Han, J.; Hindrichs, O.; Khukhunaishvili, A.; Lo, K. H.; Tan, P.; Verzetti, M.; Chou, J. P.; Contreras-Campana, E.; Gershtein, Y.; Gómez Espinosa, T. A.; Halkiadakis, E.; Heindl, M.; Hidas, D.; Hughes, E.; Kaplan, S.; Kunnawalkam Elayavalli, R.; Kyriacou, S.; Lath, A.; Nash, K.; Saka, H.; Salur, S.; Schnetzer, S.; Sheffield, D.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Foerster, M.; Heideman, J.; Riley, G.; Rose, K.; Spanier, S.; Thapa, K.; Bouhali, O.; Celik, A.; Dalchenko, M.; De Mattia, M.; Delgado, A.; Dildick, S.; Eusebi, R.; Gilmore, J.; Huang, T.; Juska, E.; Kamon, T.; Mueller, R.; Pakhotin, Y.; Patel, R.; Perloff, A.; Perniè, L.; Rathjens, D.; Rose, A.; Safonov, A.; Tatarinov, A.; Ulmer, K. A.; Akchurin, N.; Cowden, C.; Damgov, J.; Dragoiu, C.; Dudero, P. R.; Faulkner, J.; Kunori, S.; Lamichhane, K.; Lee, S. W.; Libeiro, T.; Undleeb, S.; Volobouev, I.; Wang, Z.; Delannoy, A. G.; Greene, S.; Gurrola, A.; Janjam, R.; Johns, W.; Maguire, C.; Melo, A.; Ni, H.; Sheldon, P.; Tuo, S.; Velkovska, J.; Xu, Q.; Arenton, M. W.; Barria, P.; Cox, B.; Goodell, J.; Hirosky, R.; Ledovskoy, A.; Li, H.; Neu, C.; Sinthuprasith, T.; Sun, X.; Wang, Y.; Wolfe, E.; Xia, F.; Clarke, C.; Harr, R.; Karchin, P. E.; Lamichhane, P.; Sturdy, J.; Belknap, D. A.; Dasu, S.; Dodd, L.; Duric, S.; Gomber, B.; Grothe, M.; Herndon, M.; Hervé, A.; Klabbers, P.; Lanaro, A.; Levine, A.; Long, K.; Loveless, R.; Ojalvo, I.; Perry, T.; Pierro, G. A.; Polese, G.; Ruggles, T.; Savin, A.; Sharma, A.; Smith, N.; Smith, W. H.; Taylor, D.; Woods, N.; CMS Collaboration

    2016-12-01

    Measurements are presented of the cross section for the production of at least four jets, of which at least two originate from b quarks, in proton-proton collisions. Data collected with the CMS detector at the LHC at a center-of-mass energy of 7 TeV are used, corresponding to an integrated luminosity of 3 pb-1 . The cross section is measured as a function of the jet transverse momentum for pT>20 GeV , and of the jet pseudorapidity for |η | <2.4 (b jets), 4.7 (untagged jets). The correlations in azimuthal angle and pT between the jets are also studied. The inclusive cross section is measured to be σ (p p →2 b +2 j +X )=69 ±3 (stat )±24 (syst ) nb . The η and pT distributions of the four jets and the correlations between them are well reproduced by event generators that combine perturbative QCD calculations at next-to-leading-order accuracy with contributions from parton showers and multiparton interactions.

  15. A spiking neuron model for synchronous flashing of fireflies.

    PubMed

    Kim, DaeEun

    2004-01-01

    Certain species of fireflies show a group behavior of synchronous flashing. Their synchronized and rhythmic flashing has received much attention among many researchers, and there has been a study of biological models for their entrainment of flashing. The synchronous behavior of fireflies resembles the firing synchrony of integrate-and-fire neurons with excitatory or inhibitory connections. This paper shows an analysis of spiking neurons specialized for a firefly flashing model, and provides simulation results of multiple neurons with various transmission delays and coupling strengths. It also explains flashing patterns of some firefly species and examines the synchrony conditions depending on transmission delays and coupling strengths.

  16. The Flash Grab Effect

    PubMed Central

    Cavanagh, Patrick; Anstis, Stuart

    2013-01-01

    When an object moves back and forth, its trajectory appears significantly shorter than it actually is. The object appears to stop and reverse well before its actual reversal point, as if there is some averaging of location within a window of about 100 ms (Sinico et al, 2009). Surprisingly, if a bar is flashed at the physical end point of the trajectory, right on top of the object, just as it reverses direction, the flash is also shifted – grabbed by the object – and is seen at the perceived endpoint of the trajectory rather than the physical endpoint. This can shift the perceived location of the flash by as much as 2 or 3 times its physical size and by up to several degrees of visual angle. We first show that the position shift of the flash is generated by the trajectory shortening, as the same shift is seen with or without the flash. The flash itself is only grabbed if it is presented within a small spatiotemporal attraction zone around the physical end point of the trajectory. Any flash falling in that zone is pulled toward the perceived endpoint. The effect scales linearly with speed, up to a maximum, and is independent of the contrast of the moving stimulus once it is above 5%. Finally, we demonstrate that this position shift requires attention. These results reveal a new “flash grab” effect in the family of motion-induced position shifts. Although it most resembles the flash drag effect, it differs from this in the following ways: 1) it has a different temporal profile, 2) it requires attention, 3) it is about 10 times larger. PMID:23872166

  17. The flash grab effect.

    PubMed

    Cavanagh, Patrick; Anstis, Stuart

    2013-10-18

    When an object moves back and forth, its trajectory appears significantly shorter than it actually is. The object appears to stop and reverse well before its actual reversal point, as if there is some averaging of location within a window of about 100 ms (Sinico et al., 2009). Surprisingly, if a bar is flashed at the physical end point of the trajectory, right on top of the object, just as it reverses direction, the flash is also shifted - grabbed by the object - and is seen at the perceived endpoint of the trajectory rather than the physical endpoint. This can shift the perceived location of the flash by as much as 2 or 3 times its physical size and by up to several degrees of visual angle. We first show that the position shift of the flash is generated by the trajectory shortening, as the same shift is seen with or without the flash. The flash itself is only grabbed if it is presented within a small spatiotemporal attraction zone around the physical end point of the trajectory. Any flash falling in that zone is pulled toward the perceived endpoint. The effect scales linearly with speed, up to a maximum, and is independent of the contrast of the moving stimulus once it is above 5%. Finally, we demonstrate that this position shift requires attention. These results reveal a new "flash grab" effect in the family of motion-induced position shifts. Although it most resembles the flash drag effect, it differs from this in the following ways: (1) it has a different temporal profile, (2) it requires attention, (3) it is about 10 times larger. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Understanding Green Flashes

    NASA Astrophysics Data System (ADS)

    Young, Andrew T.

    1998-05-01

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

  19. A CFD study of gas-solid jet in a CFB riser flow

    SciTech Connect

    Li, Tingwen; Guenther, Chris

    2012-03-01

    Three-dimensional high-resolution numerical simulations of a gas–solid jet in a high-density riser flow were conducted. The impact of gas–solid injection on the riser flow hydrodynamics was investigated with respect to voidage, tracer mass fractions, and solids velocity distribution. The behaviors of a gas–solid jet in the riser crossflow were studied through the unsteady numerical simulations. Substantial separation of the jetting gas and solids in the riser crossflow was observed. Mixing of the injected gas and solids with the riser flow was investigated and backmixing of gas and solids was evaluated. In the current numerical study, both the overall hydrodynamics of riser flow and the characteristics of gas–solid jet were reasonably predicted compared with the experimental measurements made at NETL.

  20. Jet Impingement and Forced Convection Cooling Experimental Study in Rotating Turbine Blades

    NASA Astrophysics Data System (ADS)

    Li, Hsin-Lung; Chiang, Hsiao-Wei D.; Hsu, Chih-Neng

    2011-06-01

    Both jet impingement and forced convection are attractive cooling mechanisms widely used in cooling gas turbine blades. Convective heat transfer from impinging jets is known to yield high local and area averaged heat transfer coefficients. Impingement jets are of particular interest in the cooling of gas turbine components where advancement relies on the ability to dissipate extremely large heat loads. Current research is concerned with the measurement and comparison of both jet impingement and forced convection heat transfer in the Reynolds number range of 10,000 to 30,000. This study is aimed at experimentally testing two different setups with forced convection and jet impingement in rotating turbine blades up to 700 RPM. This research also observes Coriolis force and impingement cooling inside the passage during rotating conditions within a cooling passage. Local heat transfer coefficients are obtained for each test section using thermocouple technique with slip rings. The cross section of the passage is 10 mm × 10 mm without ribs and the surface heating condition has enforced uniform heat flux. The forced convection cooling effects were studied using serpentine passages with three corner turns under different rotating speeds and different inlet Reynolds numbers. The impingement cooling study uses a straight passage with a single jet hole under different Reynolds numbers of the impingement flow and the cross flow. In summary, the main purpose is to study the rotation effects on both the jet impingement and the serpentine convection cooling types. Our study shows that rotation effects increase serpentine cooling and reduce jet impingement cooling.

  1. Physiologically assessed hot flashes and endothelial function among midlife women.

    PubMed

    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 < 0.05) indicated that among the younger tertile of women in the sample (age 40-53 years), the presence of 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.

  2. Initiation Locations of Lightning Flashes in Two Florida Thunderstorms

    NASA Astrophysics Data System (ADS)

    Marshall, T. C.; Karunarathna, N.; Stolzenburg, M.; Karunarathne, S.

    2015-12-01

    In this presentation we investigate the initiation locations of all intracloud (IC) and cloud-to-ground (CG) lightning flashes in two small thunderstorms which occurred over NASA/Kennedy Space Center on July 22, 2011. Initiation points of 47 of the 58 lightning flashes (19 IC and 28 CG) were identified using the first initial breakdown (IB) pulse of each flash measured with E-change data. In this study 32 of the flashes had an LDAR2 (VHF) location coincident with the first IB pulse. For 15 flashes we used Position By Fast Antenna or PBFA [Karunarathne et al., 2013, JGR Atmospheres] to determine the location of the first IB pulse. (The remaining flashes had neither LDAR2 nor PBFA locations of the first IB pulse.) All these initiation points were then mapped onto radar reflectivity of the parent thundercloud. The initiation points of the flashes tend to cluster in specific regions in thundercloud. Lightning activity in both thunderstorms lasted 35 minutes, and all the flash initiation points in each storm occurred within a horizontal region of 4 km by 8 km. Flash initiation altitudes for IC flashes of the two thunderstorms ranged from 5.1 km to 12.1 km altitude while for CG flashes the altitude ranged from 4.6 km to 8.1 km. Based on available radar data for 14 IC flashes and 27 CG flashes, all but one of the IC flashes originated in 10 dBZ - 30 dBZ reflectivity regions while 22 of the CG flashes originated in 30 dBZ - 40 dBZ reflectivities. During the lifetimes of these two storms, no Narrow Bipolar Events occurred.

  3. Theoretical study of reactive and nonreactive turbulent coaxial jets

    NASA Technical Reports Server (NTRS)

    Gupta, R. N.; Wakelyn, N. T.

    1976-01-01

    The hydrodynamic properties and the reaction kinetics of axisymmetric coaxial turbulent jets having steady mean quantities are investigated. From the analysis, limited to free turbulent boundary layer mixing of such jets, it is found that the two-equation model of turbulence is adequate for most nonreactive flows. For the reactive flows, where an allowance must be made for second order correlations of concentration fluctuations in the finite rate chemistry for initially inhomogeneous mixture, an equation similar to the concentration fluctuation equation of a related model is suggested. For diffusion limited reactions, the eddy breakup model based on concentration fluctuations is found satisfactory and simple to use. The theoretical results obtained from these various models are compared with some of the available experimental data.

  4. A study on jet initiation of detonation using multiple tubes

    NASA Astrophysics Data System (ADS)

    Ishii, K.; Tanaka, T.

    2005-11-01

    A detonator consisting of a dense bundle of small-diameter tubes (4.4 19 mm) is tested experimentally using stoichiometric mixtures of hydrogen oxygen and hydrogen air. Tests are conducted in a 5,200-mm long detonation tube fitted with a schlieren photograph section and smoked foil to record the deflagration to detonation (DDT) transition. It is confirmed that the flame jet emanating from the tube assembly causes detonation initiation immediately downstream of the detonator, with little dependence on the size of the detonation tube. For the fuel air mixture, the insertion of Shchelkin spirals into each of the smaller tubes enhances the development of the turbulent flame jet, leading to a shorter DDT distance. Multi-point spark ignition is also shown to provide a further reduction in the DDT distance compared to single-point ignition.

  5. Numerical study of twin-jet impingement upwash flow

    NASA Technical Reports Server (NTRS)

    Pegues, W. J.; Vanka, S. P.

    1990-01-01

    Two horizontally spaced jets impinging normally on a flat surface create a fountain upwash flow due to the collision of the radially flowing wall jets. This fountain flow is of importance to the dynamics and propulsion of STOVL aircraft. The fountain flow influences the lift forces on the aircraft and the ingestion of hot gases and debris by the engine inlet. In this paper, a multigrid based finite-difference numerical procedure has been applied to solve the equations governing this three-dimensional flow. The standard k-epsilon turbulence model has been used. Comparisons with experimental data reveal that while the mean velocities are predicted with reasonable accuracy, the turbulent kinetic energies are seriously in error. The reasons for this discrepancy could be the intense unsteadiness and large-scale structures of the flow in the near-wall region, which cannot be captured well by any Reynolds-averaged turbulence model.

  6. Jet azimuthal decorrelation studies with the D-zero detector

    SciTech Connect

    Feher, S.

    1996-10-01

    Experimental results on the measurement of the azimuthal decorrelation between jets with pseudorapidity separation up to five units are presented. The data were taken at the Fermi National Accelerator Laboratory during the 1992-1993 collider run with the D{null} detector using {ital p{anti p}} collisions at center-of-mass energy {radical}{ital s} = 1.8 TeV. These results are compared to next-to-leading order (NLO) QCD predictions and to two leading-log approximations (LLA) where the leading terms are resummed to all orders in {alpha}{sub s}. The final state jets as predicted by NLO QCD show less azimuthal decorrelation than the data. The parton showering LLA Monte Carlo HERWIG describes the data well; an analytical LLA calculation based on Balitsky-Faclin-Kuraev-Lipatov resummation predicts more decorrelation than is present in the data.

  7. Computational and Experimental Studies of Jet Fuel Combustion

    DTIC Science & Technology

    2009-08-14

    reference flame with a prescribed velocity and thermal field and then to perturb such a flame with known amounts of either jet fuel or surrogates. This... thermal conductivity (TCD), flame ionization (FID) and mass spectrometry detectors (MSD) (Agilent 5973N). The instrument can separate and quantify...location of the peak temperature was approached. This sequence was in line with the anticipated kinetic behavior based on thermal decomposition of

  8. Laser irradiated gas jet: A spectroscopic experimental and theoretical study

    SciTech Connect

    Lee, R.W.; Matthews, D.L.; Koppel, L.; Busch, G.E.; Charatis, G.; Dunning, M.J.; Mayer, F.J.

    1983-09-01

    We present x-ray spectroscopic measurements of the longitudinal electron density profile and the longitudinal and transverse electron temperature profiles for a laser irradiated gas jet. We attempt to verify our spectroscopic method by laser interferometry and by comparison of inferred quantities to those determined from laser plasma interaction simulations. Because temperature profiles were time dependent, we used a theoretical time dependent radiation transport code to analyze the data.

  9. Long Penetration Mode Counterflowing Jets for Supersonic Slender Configurations - A Numerical Study

    NASA Technical Reports Server (NTRS)

    Venkatachari, Balaji Shankar; Cheng, Gary; Chang, Chau-Layn; Zichettello, Benjamin; Bilyeu, David L.

    2013-01-01

    A novel approach of using counterflowing jets positioned strategically on the aircraft and exploiting its long penetration mode (LPM) of interaction towards sonic-boom mitigation forms the motivation for this study. Given that most previous studies on the counterflowing LPM jet have all been on blunt bodies and at high supersonic or hypersonic flow conditions, exploring the feasibility to obtain a LPM jet issuing from a slender body against low supersonic freestream conditions is the main focus of this study. Computational fluid dynamics computations of axisymmetric models (cone-cylinder and quartic geometry), of relevance to NASA's High Speed project, are carried out using the space-time conservation element solution element viscous flow solver with unstructured meshes. A systematic parametric study is conducted to determine the optimum combination of counterflowing jet size, mass flow rate, and nozzle geometry for obtaining LPM jets. Details from these computations will be used to assess the potential of the LPM counterflowing supersonic jet as a means of active flow control for enabling supersonic flight over land and to establish the knowledge base for possible future implementation of such technologies.

  10. An Experimental Study of Plunging Liquid Jet Induced Air Carryunder and Dispersion

    DTIC Science & Technology

    1992-03-31

    Plunging Liquid Jet - The Air Entrainment Process". It is intended that this paper will be finalized and...the fifth quarterly report for ONR grant N00014-91-J-1271, "An Experimental Study of Plunging Liquid Jet Induced Air Carryunder and Dispersion" (Lahey...Drew - CoPI). rhis report period has been concerned with performing an analysis of the air entrainment process associated with a plunging liquid

  11. A Laboratory Astrophysical Jet to Study Canonical Flux Tubes

    NASA Astrophysics Data System (ADS)

    You, Setthivoine; von der Linden, Jens; Vereen, Keon; Carroll, Evan; Kamikawa, Yu; Lavine, Eric Sander

    2013-10-01

    A new research program aims to simulate a magnetically driven jet launched by an accretion disk in a laboratory experiment. The experiment replaces an accretion disk that would rotate at impractical speeds in the laboratory with three concentric annular electrodes, independently biased by two sets of pulsed power supplies to generate magnetized plasma shear flows. With three electrodes, the radial electric field can be set up to approximate the rotation profile of an accretion disk. The primary diagnostics include arrays of magnetic probes to measure 3D magnetic fields and arrays of lines-of-sight to measure 3D ion flows from vector tomography of ion Doppler spectral lines. The symmetry of fast gas puff sources is fine-tuned with a fast ion gauge to remove any anchoring effects of discrete gas holes on the azimuthal rotation of the plasma jet. The aim is to understand how magnetically driven astrophysical jets become long and collimated, how they become unstable or turbulent, and investigate the physics from a canonical flux tube point-of-view. A canonical flux tube is a fundamental tube of magnetic flux with helical flows. This work is supported by the US DOE Grant DE-SC0010340

  12. Study of lubricant jet flow phenomena in spur gears

    NASA Technical Reports Server (NTRS)

    Akin, L. S.; Townsend, D. P.; Mross, J. J.

    1974-01-01

    Lubricant jet flow impingement and penetration depth into a gear tooth space were measured at 4920 and 2560 rpm using a 8.89 cm (3.5 inch) pitch diameter 8 pitch spur gear at oil pressures from 70,000 to 410,000 n/sqm (10 psi to 60 psi). A high speed motion picture camera was used with xenon and high speed stroboscopic lights to slow down and stop the motion of the oil jet. An analytical model was developed for the vectorial impingement dept and for the impingement depth with tooth space windage effects included. The windage effects for oil drop size greater than .0076 cm (.003 inches). The analytical impingement dept compared favorably with experimental results above an oil jet pressure of 70,000 n/sqm (10psi). There was further penetration into the tooth space after impingement, but much of this oil was thrown out of the tooth space without further contacting the gear teeth.

  13. Machine Learning Predictions of Flash Floods

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

  14. A comparative study of Ni0.7Zn0.3Fe2O4 obtained by sol-gel auto-combustion and flash combustion methods

    NASA Astrophysics Data System (ADS)

    Sutka, A.; Lagzdina, S.; Mezinskis, G.; Pludons, A.; Vitina, I.; Timma, L.

    2011-12-01

    In this study, the nickel-zinc ferrites were prepared via two different methods: the sol-gel auto combustion method and the flash combustion method. Obtained reaction products were sintered at different temperatures 900, 1100 and 1300 °C. The structural and microstructural, as well as electric and dielectric properties of different samples were discussed. The synthesis method has a marked effect on crystalline order, grain size and its distribution, electrical resistivity and dielectric properties.

  15. The Sileye-3/Alteino experiment for the study of light flashes, radiation environment and astronaut brain activity on board the International Space Station.

    PubMed

    Bidoli, Vittorio; Casolino, Marco; De Pascale, Maria Pia; Furano, Gianluca; Minori, Mario; Morselli, Aldo; Narici, Livio; Picozza, Piergiorigio; Reali, Enzo; Sparvoli, Roberta; Fuglesang, Christer; Sannita, Walter; Carlson, Per; Castellini, Guido; Galper, Arkady; Korotkov, Mikhail; Popov, Alexander; Navilov, Nikita; Avdeev, Sergei; Benghin, Victor; Salnitskii, Victor; Shevchenko, Olga; Boezio, Mirko; Bonvicini, Walter; Vacchi, Andrea; Zampa, Gianluigi; Zampa, Nicola; Mazzenga, Giuseppe; Ricci, Marco; Spillantini, Piero; Vittori, Roberto

    2002-12-01

    In this work we describe the instrument Sileye-3/Alteino, placed on board the International Space Station in April 2002. The instrument is constituted by an Electroencephalograph and a cosmic ray silicon detector. The scientific aims include the investigation of the Light Flash phenomenon, the measurement of the radiation environment and the nuclear abundance inside the ISS and the study of astronaut brain activity in space when subject to cosmic rays.

  16. Bouncing Jets

    NASA Astrophysics Data System (ADS)

    Wadhwa, Navish; Vlachos, Pavlos; Jung, Sunghwan

    2011-11-01

    Contrary to common intuition, free jets of fluid can ``bounce'' off each other on collision in mid-air, through the effect of a lubricating air film that separates the jets. We have developed a simple experimental setup to stably demonstrate and study the non-coalescence of jets on collision. We present the results of an experimental investigation of oblique collision between two silicone oil jets, supported by a simple analytical explanation. Our focus is on elucidating the role of various physical forces at play such as viscous stresses, capillary force and inertia. A parametric study conducted by varying the nozzle diameter, jet velocity, angle of inclination and fluid viscosity reveals the scaling laws for the quantities involved such as contact time. We observed a transition from bouncing to coalescence with an increase in jet velocity and inclination angle. We propose that a balance between the contact time of jets and the time required for drainage of the trapped air film can provide a criterion for transition from non-coalescence to coalescence.

  17. Monte Carlo Study of Quark & Gluon Jets at √{ s} = 2 . 76 & 7 TeV With Inclusive Jet Comparison to ATLAS Measurements

    NASA Astrophysics Data System (ADS)

    Mistro, Matthew

    2015-10-01

    In the study of heavy ion collisions, pp collisions are a necessity of understanding as a baseline due to producing minimal hot dense matter. Different Monte Carlo simulations with various tunes are studied for these pp collisions at √{ s} = 2 . 76 & 7 TeV. The primal focus being on the charged multiplicity as a function of the ratio of the charged particles transverse momenta, pTch , to the originating jet transverse momentum, pTjet , referred to as z. As they cannot directly be seen at the LHC, simulations find the differences of said functions to originating from a quark or gluon jet for varied pTjet cuts of 40 jets via photon processes are compared to that of hard QCD quark jets.

  18. Theoretical study of refraction effects on noise produced by turbulent jets

    NASA Technical Reports Server (NTRS)

    Graham, E. W.; Graham, B. B.

    1975-01-01

    The transmission of acoustic disturbances from the interior of a jet into the ambient air is studied. The jet is assumed infinitely long with mean velocity profile independent of streamwise location. The noise generator is a sequence of transient sources drifting with the local fluid and confined to a short length of the jet. In Part 1, supersonic jets are considered. Numerical results for mean-square pressure versus angle in the far-field show unexpected peaks which are very sharp. Analysis of simplified models indicates that these are complex quasi-resonant effects which appear to the stationary observer in a high frequency range. The peaks are real for the idealized model, but would be smoothed by mathematical integration over source position, velocity, and frequency. Subsonic jets were considered in part 2, and a preliminary study of the near-field was attempted. Mean-square radial displacements (or mean radial energy flow or space-time correlations of radial pressure gradient) are first found for very simple cases. The most difficult case studied is a sequence of transient sources at the center of a uniform-velocity circular cylindrical jet. Here a numerical triple integration is required and seems feasible although only preliminary results for mean square radial displacement are now available. These preliminary results show disturbances decreasing with increasing radial distance, and with increasing distance upstream and downstream from the source. A trend towards greater downstream disturbances appears even in the near field.

  19. Study of Large Scale Jet in M 87 at the Multi-Wavebands

    NASA Astrophysics Data System (ADS)

    Meng, D.-M.; Wang, C.-C.; Zhou, H.-Y.

    2007-09-01

    The large scale jet of the radio galaxy M87 has been observed in high resolution at radio and optical wavelengths as well as X-ray band, the spectra of the knots are commonly believed to be generated from synchrotron emission. The authors study spectra of the knots in the jet at multi-wavebands by using Kardashev-Packolczyk radiation model, and obtain the corresponding Doppler factor. Combined with superluminal motion, they derive the Lorentz factor and the angle to the line of sight for individual knots. Their results show that M87 has a slightly bend as well as a moderated relativistic jet. They also find that the bulk velocity of its jet decelerates as it flows out.

  20. Numerical Study of a Continuum Sonic Jet Interacting with a Rarefield Flow

    NASA Technical Reports Server (NTRS)

    Glass, Christoper E.

    1997-01-01

    The results of a numerical study with flow and boundary conditions based on an experiment of a continuum sonic jet interacting with rarefied flow about a sharp leading edge flat plate at zero incidence are presented. Comparisons are made between computational fluid dynamics (CFD) and direct simulation Monte Carlo (DSMC) solutions which provide an assessment of applying each technique to the flow conditions of the experiment. An analysis of the CFD results revealed a correlation between the interaction interface of the jet continuum breakdown surface and a non-dimensional parameter derived from jet and free stream flow conditions. Using the breakdown surface from the correlation, the continuum jet was uncoupled from the interaction, thus allowing an uncoupled CFD-DSMC solution to be obtained. Also, a nearest neighbor collision algorithm, similar to the subcell technique, was implemented in the DSMC solution technique. The comparison between CFD and DSMC results shows good qualitative agreement in the interaction region and good quantitative agreement elsewhere.

  1. Plasma-wall interaction studies with optimized laser-produced jets

    SciTech Connect

    Renner, O.; Krousky, E.; Smid, M.; Pisarczyk, T.; Chodukowski, T.; Kalinowska, Z.; Pisarczyk, P.; Ullschmied, J.; Dalimier, E.

    2011-09-15

    The production of the laser-produced plasma jets at burnt-through low-Z foils was optimized by using three-frame interferometry. When striking secondary targets, these jets of energetic particles represent an efficient tool for the investigation of transient phenomena at surfaces of the plasma-exposed solids. Two sets of precisely measured x-ray spectroscopic data demonstrate diagnostic potential of the collimated jets in the plasma-wall interaction studies: Blue Doppler shifts of the Al jet self-emission visualize ion deceleration in the near-wall region. Local depressions found in Al Ly{gamma} profiles emitted from Al/Si(PMMA) targets indicate charge exchange between the Al XIII and fully stripped C ions.

  2. Study of the heavy flavor content of jets produced in W events at the Tevatron collider

    SciTech Connect

    G. Apollinari

    2002-08-01

    We present a detailed study of the heavy flavor content in the W + jet data sample collected with the CDF detector during the 1992-1995 collider run at Fermilab. Rates of heavy flavor jets, identified via the observation of secondary vertices or semileptonic decays of b and c quarks, are in good agreement with a standard model simulation including production of the top quark. An exception is the number of events in which a single jet has both a secondary vertex and a semileptonic decay tag. In the W + 2,3 jet data, we expect 4.4 {+-} 0.6 and we find 13 such events. The kinematic properties of this small sample of events are statistically difficult to reconcile with the simulation of standard model processes.

  3. A study of jet impingement on curved surfaces followed by oblique introduction into a freestream flow

    NASA Technical Reports Server (NTRS)

    Tatom, J. W.; Schnurr, N. M.; Williamson, J. W.; Dunlap, J. H.

    1972-01-01

    An experimental investigation of the temperature and velocity fields generated by a two-dimensional transverse jet was conducted. An approximate analysis of a deflected radial plane jet was developed. An analytical model of aircraft ingestion was extended to include computation of the inlet flow field. An investigation of the use of flaps as thrust reversers was initiated. Analyses of the impingement of a round incompressible and a round compressible jet on a arbitrary axisymmetric surface were completed. A computer study of the effects on performance of thrust reverser geometry was completed and the results compared with existing data. An experimental investigation of three-dimensional jet impingement on nonplane surfaces was also initiated.

  4. Study of intense femtosecond laser propagation into a dense Ar gas and cluster jet

    SciTech Connect

    Caillaud, T.; Blasco, F.; Bonte, C.; Dorchies, F.; Mora, P.

    2006-03-15

    The propagation of an intense (up to 10{sup 17} W/cm{sup 2}) and short laser pulse (down to 40 fs) is studied through a well characterized high density Ar cluster jet obtained at the output of a supersonic nozzle. The x-ray emission from the irradiated clusters is measured as a function of the focusing depth inside the jet, with a spatial resolution of the emitting plasma. A strong refraction of the laser pulse is observed, limiting the interaction at the entrance of the jet and decreasing the effective laser intensity on clusters. Calculations indicate that it is due to the ionization of the residual gaseous phase present in the cluster jet. As the focal volume is modified, this effect should be considered for any quantitative analysis of the laser-cluster interaction.

  5. Impact of septal flash and left ventricle contractile reserve on positive remodeling during 1 year cardiac resynchronization therapy: the multicenter ViaCRT study.

    PubMed

    Gąsior, Zbigniew; Płońska-Gościniak, Edyta; Kułach, Andrzej; Wita, Krystian; Mizia-Stec, Katarzyna; Szwed, Hanna; Kasprzak, Jarosław; Tomaszewski, Andrzej; Sinkiewicz, Władysław; Wojciechowska, Celina

    2016-04-01

    Cardiac resynchronization therapy (CRT) has been shown to improve outcomes in patients with systolic heart failure (HFREF). However, the relatively high non-responder rate results in a need for more precise qualification for CRT. The ViaCRT study was designed to determine the role of contractile reserve and dyssynchrony parameters in predicting CRT response. The purpose of this analysis was to determine the effect of baseline septal flash and contractile reserve (CR) on clinical and echocardiographic parameters of response to CRT in 12-month follow-up. One hundred thirty-three guideline-selected CRT candidates (both ischemic and non-ischemic heart failure with reduced ejection fraction) were enrolled in the study. Baseline study population characteristics were: left ventricle ejection fraction (LVEF) 25 ±6%, QRS 165 ±25 ms, NYHA class III (90%) and IV (10%). In subjects with septal flash (SF) registered before CRT implantation improvement in LVEF (14 ±2% vs. 8 ±1%, p < 0.05) and left ventricle (LV) systolic (63 ±10 ml vs. 36 ±6 ml, p < 0.05) and diastolic (46 ±10 ml vs. 32 ±7, p < 0.05) volumes was more pronounced than in patients without SF. In patients with CR (defined as LVEF increase by 20% or 4 viable segments) improvement in echo parameters was not significantly different then in the CR- group. Neither SF nor CR was associated with improvement in NYHA class. Subgroup analysis revealed that only in non-ischemic HF patients is presence of septal flash associated with LV function improvement after CRT. In non-ischemic HF patients septal flash is a helpful parameter in prediction of LV remodeling after 12 months of resynchronization therapy.

  6. Experimental study of three-dimensional fin-channel charge trapping flash memories with titanium nitride and polycrystalline silicon gates

    NASA Astrophysics Data System (ADS)

    Liu, Yongxun; Matsukawa, Takashi; Endo, Kazuhiko; O'uchi, Shinichi; Tsukada, Junichi; Yamauchi, Hiromi; Ishikawa, Yuki; Mizubayashi, Wataru; Morita, Yukinori; Migita, Shinji; Ota, Hiroyuki; Masahara, Meishoku

    2014-01-01

    Three-dimensional (3D) fin-channel charge trapping (CT) flash memories with different gate materials of physical-vapor-deposited (PVD) titanium nitride (TiN) and n+-polycrystalline silicon (poly-Si) have successfully been fabricated by using (100)-oriented silicon-on-insulator (SOI) wafers and orientation-dependent wet etching. Electrical characteristics of the fabricated flash memories including statistical threshold voltage (Vt) variability, endurance, and data retention have been comparatively investigated. It was experimentally found that a larger memory window and a deeper erase are obtained in PVD-TiN-gated metal-oxide-nitride-oxide-silicon (MONOS)-type flash memories than in poly-Si-gated poly-Si-oxide-nitride-oxide-silicon (SONOS)-type memories. The larger memory window and deeper erase of MONOS-type flash memories are contributed by the higher work function of the PVD-TiN metal gate than of the n+-poly-Si gate, which is effective for suppressing electron back tunneling during erase operation. It was also found that the initial Vt roll-off due to the short-channel effect (SCE) is directly related to the memory window roll-off when the gate length (Lg) is scaled down to 46 nm or less.

  7. Floods and Flash Flooding

    MedlinePlus

    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 ...

  8. Fireball Flash over Russia

    NASA Image and Video Library

    2013-02-16

    This image shows the flash above Chelyabinsk, Russia, from the fireball streaking through the sky on Feb. 15, 2013. The small asteroid was approximately 56 to 66 feet in diameter. The picture was taken by a local, M. Ahmetvaleev.

  9. A spatially collocated sound thrusts a flash into awareness.

    PubMed

    Aller, Máté; Giani, Anette; Conrad, Verena; Watanabe, Masataka; Noppeney, Uta

    2015-01-01

    To interact effectively with the environment the brain integrates signals from multiple senses. It is currently unclear to what extent spatial information can be integrated across different senses in the absence of awareness. Combining dynamic continuous flash suppression (CFS) and spatial audiovisual stimulation, the current study investigated whether a sound facilitates a concurrent visual flash to elude flash suppression and enter perceptual awareness depending on audiovisual spatial congruency. Our results demonstrate that a concurrent sound boosts unaware visual signals into perceptual awareness. Critically, this process depended on the spatial congruency of the auditory and visual signals pointing towards low level mechanisms of audiovisual integration. Moreover, the concurrent sound biased the reported location of the flash as a function of flash visibility. The spatial bias of sounds on reported flash location was strongest for flashes that were judged invisible. Our results suggest that multisensory integration is a critical mechanism that enables signals to enter conscious perception.

  10. A spatially collocated sound thrusts a flash into awareness

    PubMed Central

    Aller, Máté; Giani, Anette; Conrad, Verena; Watanabe, Masataka; Noppeney, Uta

    2015-01-01

    To interact effectively with the environment the brain integrates signals from multiple senses. It is currently unclear to what extent spatial information can be integrated across different senses in the absence of awareness. Combining dynamic continuous flash suppression (CFS) and spatial audiovisual stimulation, the current study investigated whether a sound facilitates a concurrent visual flash to elude flash suppression and enter perceptual awareness depending on audiovisual spatial congruency. Our results demonstrate that a concurrent sound boosts unaware visual signals into perceptual awareness. Critically, this process depended on the spatial congruency of the auditory and visual signals pointing towards low level mechanisms of audiovisual integration. Moreover, the concurrent sound biased the reported location of the flash as a function of flash visibility. The spatial bias of sounds on reported flash location was strongest for flashes that were judged invisible. Our results suggest that multisensory integration is a critical mechanism that enables signals to enter conscious perception. PMID:25774126

  11. Experimental study on spray characteristics of alternate jet fuels using Phase Doppler Anemometry

    NASA Astrophysics Data System (ADS)

    Kannaiyan, Kumaran; Sadr, Reza

    2013-11-01

    Gas-to-Liquid (GTL) fuels have gained global attention due to their cleaner combustion characteristics. The chemical and physical properties of GTL jet fuels are different from conventional jet fuels owing to the difference in their production methodology. It is important to study the spray characteristics of GTL jet fuels as the change of physical properties can affect atomization, mixing, evaporation and combustion process, ultimately affecting emission process. In this work, spray characteristics of two GTL synthetic jet fuels are studied using a pressure-swirl nozzle at different injection pressures and atmospheric ambient condition. Phase Doppler Anemometry (PDA) measurements of droplet size and velocity are compared with those of regular Jet A-1 fuel at several axial and radial locations downstream of the nozzle exit. Experimental results show that although the GTL fuels have different physical properties such as viscosity, density, and surface tension, among each other the resultant change in the spray characteristics is insignificant. Furthermore, the presented results show that GTL fuel spray characteristics exhibit close similarity to those of Jet A-1 fuel. Funded by Qatar Science and Technology Park.

  12. TWO-DIMENSIONAL NUMERICAL STUDY FOR RAYLEIGH-TAYLOR AND RICHTMYER-MESHKOV INSTABILITIES IN RELATIVISTIC JETS

    SciTech Connect

    Matsumoto, Jin; Masada, Youhei

    2013-07-20

    We study the stability of a non-rotating single-component jet using two-dimensional special relativistic hydrodynamic simulations. By assuming translational invariance along the jet axis, we exclude the destabilization effect by Kelvin-Helmholtz mode. The nonlinear evolution of the transverse structure of the jet with a normal jet velocity is highlighted. An intriguing finding in our study is that Rayleigh-Taylor and Richtmyer-Meshkov type instabilities can destroy cylindrical jet configuration as a result of spontaneously induced radial oscillating motion. This is powered by in situ energy conversion between the thermal and bulk kinetic energies. The effective inertia ratio of the jet to the surrounding medium {eta} determines a threshold for the onset of instabilities. The condition {eta} < 1 should be satisfied for the transverse structure of the jet being persisted.

  13. Identification of spatial and temporal contributions of rainfalls to flash floods using neural network modelling: case study on the Lez Basin (Southern France)

    NASA Astrophysics Data System (ADS)

    Darras, T.; Borrell Estupina, V.; Kong-A-Siou, L.; Vayssade, B.; Johannet, A.; Pistre, S.

    2015-04-01

    Flash floods pose significant hazards in urbanised zones and have important human and financial implications in both the present and future due to the likelihood that global climate change will exacerbate their consequences. It is thus of crucial importance to better model these phenomena especially when they occur in heterogeneous and karst basins where they are difficult to describe physically. Toward this goal, this paper applies a recent methodology (KnoX methodology) dedicated to extracting knowledge from a neural network model to better determine the contributions and time responses of several well-identified geographic zones of an aquifer. To assess the interest of this methodology, a case study was conducted in Southern France: the Lez hydrosystem whose river crosses the conurbation of Montpellier (400 000 inhabitants). Rainfall contributions and time transfers were estimated and analysed in four geologically-delimited zones to estimate the sensitivity of flash floods to water coming from the surface or karst. The Causse de Viol-le-Fort is shown to be the main contributor to flash floods and the delay between surface and underground flooding is estimated to be three hours. This study will thus help operational flood warning services to better characterise critical rainfall and develop measurements to design efficient flood forecasting models. This generic method can be applied to any basin with sufficient rainfall-runoff measurements.

  14. Identification of spatial and temporal contributions of rainfalls to flash floods using neural network modelling: case study on the Lez basin (southern France)

    NASA Astrophysics Data System (ADS)

    Darras, T.; Borrell Estupina, V.; Kong-A-Siou, L.; Vayssade, B.; Johannet, A.; Pistre, S.

    2015-10-01

    Flash floods pose significant hazards in urbanised zones and have important implications financially and for humans alike in both the present and future due to the likelihood that global climate change will exacerbate their consequences. It is thus of crucial importance to improve the models of these phenomena especially when they occur in heterogeneous and karst basins where they are difficult to describe physically. Toward this goal, this paper applies a recent methodology (Knowledge eXtraction (KnoX) methodology) dedicated to extracting knowledge from a neural network model to better determine the contributions and time responses of several well-identified geographic zones of an aquifer. To assess the interest of this methodology, a case study was conducted in southern France: the Lez hydrosystem whose river crosses the conurbation of Montpellier (400 000 inhabitants). Rainfall contributions and time transfers were estimated and analysed in four geologically delimited zones to estimate the sensitivity of flash floods to water coming from the surface or karst. The Causse de Viols-le-Fort is shown to be the main contributor to flash floods and the delay between surface and underground flooding is estimated to be 3 h. This study will thus help operational flood warning services to better characterise critical rainfall and develop measurements to design efficient flood forecasting models. This generic method can be applied to any basin with sufficient rainfall-run-off measurements.

  15. A study of the efficacy of flashing lights to increase the salience of alcohol-gel dispensers for improving hand hygiene compliance.

    PubMed

    D'Egidio, Gianni; Patel, Rakesh; Rashidi, Babak; Mansour, Marlene; Sabri, Elham; Milgram, Paul

    2014-08-01

    Many interventions have been implemented to improve hand hygiene compliance, each with varying effects and monetary costs. Although some previous studies have addressed the issue of conspicuousness, we found only 1 study that considered improving hand hygiene by using flashing lights. Our attention theory-based hypothesis tested whether a simple red light flashing at 2-3 Hz affixed to the alcohol gel dispensers, within the main hospital entrance, would increase hand hygiene compliance over the baseline rate. Baseline and intervention observations were completed over five 60-minute periods (Monday-Friday) from 7:30 to 8:30 AM using a covert observation method. Baseline hand hygiene compliance was 12.4%. Our intervention increased compliance to 23.5% during cold weather and 27.1% during warm weather. Overall, our pooled compliance rate increased to 25.3% (P < .0001). A simple, inexpensive flashing red light affixed to alcohol gel dispensers was sufficiently salient to approximately double overall hand hygiene compliance within the main hospital entrance. We hypothesize that our intervention drew attention to the dispensers, which then reminded employees and visitors alike to wash their hands. Compliance was worse during cold days, presumably related to more individuals wearing gloves. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  16. Immunohistochemical and mutational analysis of FLASH in gastric carcinomas.

    PubMed

    Jeong, Eun Goo; Lee, Sung Hak; Lee, Hae Woo; Soung, Young Hwa; Yoo, Nam Jin; Lee, Sug Hyung

    2007-08-01

    FLASH was initially identified as a pro-apoptotic protein that transmits an apoptosis signal during death receptor-induced apoptosis. Additionally, diverse biologic roles of FLASH, including TNF-induced NF-kappaB activation, cell-cycle progression and cell division, have been identified. Although such functions are important in cancer pathogenesis, little is known about the alterations of FLASH gene and FLASH protein expression in human cancers. In this study, we analyzed the expression of FLASH protein in 60 gastric adenocarcinomas by immunohistochemistry. We furthermore analyzed mutation of FLASH in exon 8, where two polyadenine tracts ((A)8 and (A)9) are present, by single-strand conformation polymorphism (SSCP) assay in 184 gastric adenocarcinomas. By immunohistochemistry, FLASH protein expression in cancer cells was detected positively in 42 gastric carcinoma tissues (70%), whereas its expression in epithelial cells of normal gastric mucosa was shown as no or very weak intensity. Mutational analysis detected one FLASH mutation in the gastric carcinomas (0.5%). The increased expression of FLASH in the malignant gastric epithelial cells compared to the normal mucosal epithelial cells suggests that FLASH expression may play a role in gastric tumorigenesis. Also, the data suggest that somatic mutation of FLASH is a rare event in gastric carcinomas.

  17. Flash floods in the Sahara: A case study for the 28th January 2013 flood in Qena-Egypt

    NASA Astrophysics Data System (ADS)

    Badawy, Moawad; Omar, Ahmed; Mamtimin, Buhalqem

    2014-05-01

    Understanding the torrential rainfall and its consequent surface runoff in the Sahara is a crucial issue for better flood protection and water management plans. This is often hampered by lack of the appropriate in situ measurements. Even now the satellite derived rainfall suffers from great uncertainty. Thus, we adjusted the data obtained from real-time satellite rainfall coverage (HYDIS) using the in situ observed rainfall (Robs). Hydro-morphological parameters were then integrated with the empirical curve number (CN) approach to estimate the surface runoff in Qena, Egypt during the 28th January 2013 flash flood event. We deduced that the study area received a total precipitation (∑Rcum) of ~35.6×106 [mm] and a total rain volume (∑Rvol) of ~88.9×109 [m3] mainly from wadi Qena (89.8%). The majority of the rainfalls fell at light intensity (<2.5 [mm hr-1]). The estimated total surface runoff (∑Qsur) was 26.5×106 mm and the total runoff volume (∑Qvol) was 66.2×106 [m3]. The total surface transmission losses (∑Tlos) were calculated as 9.1×106 [mm], which represents about 25.6% of the total precipitation (∑Rcum) and creates substantial opportunities for alluvial aquifer recharge. The total surface runoff (∑Qsur) and flood magnitude were generally low, therefore, flood influences were restricted to the destruction of some roads in Qena but no fatalities were involved, nevertheless. Most of the running water was contained by the El Sail Canal and poured into the Nile River. It is expected that the applied method in this study will be helpful for our understanding and quantification of flood hydrology and contribute to better risk management plan in the arid and hyper-arid regions.

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

    PubMed

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

    2011-05-07

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

  19. Laser flash photolysis studies of radical-radical reaction kinetics: The HO{sub 2} + IO reaction

    SciTech Connect

    Cronkhite, J.M.; Stickel, R.E.; Nicovich, J.M.; Wine, P.H.

    1999-04-29

    Reactive iodine as a potential tropospheric O{sub 3} sink has received considerable attention recently. Laser flash photolysis of Cl{sub 2}/CH{sub 3}OH/O{sub 2}/I{sub 2}/NO{sub 2}/SF{sub 6}N{sub 2} mixtures at 308 nm has been coupled with simultaneous time-resolved detection of HO{sub 2} (by infrared tunable diode laser absorption spectroscopy) and IO (by visible absorption spectroscopy) to investigate the kinetics of the atmospherically important reaction HO{sub 2} + IO {r_arrow} products over the temperature range 274--373 K in N{sub 2} buffer gas at pressures of 12 and 25 Torr. All experiments were performed under near pseudo-first-order conditions with HO{sub 2} in excess over IO. At 298 K, the rate coefficient was determined to be (9.7 {+-} 2.9) {times} 10{sup {minus}11} cm{sup 3} molecule{sup {minus}1}s{sup {minus}1}, with the primary source of uncertainty being knowledge of the infrared line strength(s) required to convert measured HO{sub 2} absorbances to absolute concentrations. The temperature dependence of the HO{sub 2} + IO rate coefficient was found to be adequately described by the Arrhenius expression k = 9.3 {times} 10{sup {minus}12} exp(680/T) cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}. The results reported in this study are compared with other recent studies of HO{sub 2} + IO kinetics, and the potential roles of this reaction in atmospheric chemistry are discussed.

  20. Atmospheric gamma-ray and neutron flashes

    SciTech Connect

    Babich, L. P. Kudryavtsev, A. Yu. Kudryavtseva, M. L. Kutsyk, I. M.

    2008-01-15

    Gamma-ray pulses are calculated from 2D numerical simulations of an upward atmospheric discharge in a self-consistent electric field using the multigroup approach to the kinetics of relativistic runaway electrons (REs). Computed {gamma}-ray numbers and spectra are consistent with those of terrestrial {gamma}-ray flashes (TGFs) observed aboard spacecrafts. The RE flux is concentrated mainly within the domain of the Blue Jet fluorescence. This confirms that exactly the domain adjacent to a thundercloud is the source of the observed {gamma}-ray flashes. The yield of photonuclear neutrons is calculated. One {gamma}-ray pulse generates {approx}10{sup 14}-10{sup 15} neutrons. The possibility of the direct deposition of REs to the detector readings and the origin of the lightning-advanced TGFs are discussed.

  1. Phenomenology of the sound-induced flash illusion.

    PubMed

    Abadi, Richard V; Murphy, Jonathan S

    2014-07-01

    Past studies, using pairings of auditory tones and visual flashes, which were static and coincident in space but variable in time, demonstrated errors in judging the temporal patterning of the visual flashes-the sound-induced flash illusion. These errors took one of the two forms: under-reporting (sound-induced fusion) or over-reporting (sound-induced fission) of the flash numbers. Our study had three objectives: to examine the robustness of both illusions and to consider the effects of stimulus set and response bias. To this end, we used an extended range of fixed spatial location flash-tone pairings, examined stimuli that were variable in space and time and measured confidence in judging flash numbers. Our results indicated that the sound-induced flash illusion is a robust percept, a finding underpinned by the confidence measures. Sound-induced fusion was found to be more robust than sound-induced fission and a most likely outcome when high numbers of flashes were incorporated within an incongruent flash-tone pairing. Conversely, sound-induced fission was the most likely outcome for the flash-tone pairing which contained two flashes. Fission was also shown to be strongly driven by stimuli confounds such as categorical boundary conditions (e.g. flash-tone pairings with ≤2 flashes) and compressed response options. These findings suggest whilst both fission and fusion are associated with 'auditory driving', the differences in the occurrence and strength of the two illusions not only reflect the separate neuronal mechanisms underlying audio and visual signal processing, but also the test conditions that have been used to investigate the sound-induced flash illusion.

  2. SHORT CIRCUIT COORDINATION STUDY & ARC FLASH EVALUATION FOR LIQUID PROCESSING & CAPSULE STORAGE 310 FACILITY

    SciTech Connect

    TOWNE, C.M.

    2003-12-26

    The objective of this study is to provide a design basis document for the electrical distribution system for the 310 Facility in the 300 Area. The study must assure that electrical equipment is rated to withstand the available fault current under abnormal (short circuit) conditions. Under-rated equipment would result in property damage, prolonged facility outages, and possible personal injury. Also to be considered, is the coordination of protective devices. This assures that the protection device nearest a fault will open and isolate the problem area from the remainder of facility systems. The study must specify what settings are required on adjustable protective devices to achieve optimum coordination. Lastly, the study must calculate Arc Blast energies at all parts of the system so that proper Personal Protective Equipment (PPE) can be specified for energized work.

  3. Experimental studies of collisional plasma shocks and plasma interpenetration via merging supersonic plasma jets

    NASA Astrophysics Data System (ADS)

    Hsu, S. C.; Moser, A. L.; Merritt, E. C.; Adams, C. S.

    2015-11-01

    Over the past 4 years on the Plasma Liner Experiment (PLX) at LANL, we have studied obliquely and head-on-merging supersonic plasma jets of an argon/impurity or hydrogen/impurity mixture. The jets are formed/launched by pulsed-power-driven railguns. In successive experimental campaigns, we characterized the (a) evolution of plasma parameters of a single plasma jet as it propagated up to ~ 1 m away from the railgun nozzle, (b) density profiles and 2D morphology of the stagnation layer and oblique shocks that formed between obliquely merging jets, and (c) collisionless interpenetration transitioning to collisional stagnation between head-on-merging jets. Key plasma diagnostics included a fast-framing CCD camera, an 8-chord visible interferometer, a survey spectrometer, and a photodiode array. This talk summarizes the primary results mentioned above, and highlights analyses of inferred post-shock temperatures based on observations of density gradients that we attribute to shock-layer thickness. We also briefly describe more recent PLX experiments on Rayleigh-Taylor-instability evolution with magnetic and viscous effects, and potential future collisionless shock experiments enabled by low-impurity, higher-velocity plasma jets formed by contoured-gap coaxial guns. Supported by DOE Fusion Energy Sciences and LANL LDRD.

  4. Numerical study of three-dimensional liquid jet breakup with adaptive unstructured meshes

    NASA Astrophysics Data System (ADS)

    Xie, Zhihua; Pavlidis, Dimitrios; Salinas, Pablo; Pain, Christopher; Matar, Omar

    2016-11-01

    Liquid jet breakup is an important fundamental multiphase flow, often found in many industrial engineering applications. The breakup process is very complex, involving jets, liquid films, ligaments, and small droplets, featuring tremendous complexity in interfacial topology and a large range of spatial scales. The objective of this study is to investigate the fluid dynamics of three-dimensional liquid jet breakup problems, such as liquid jet primary breakup and gas-sheared liquid jet breakup. An adaptive unstructured mesh modelling framework is employed here, which can modify and adapt unstructured meshes to optimally represent the underlying physics of multiphase problems and reduce computational effort without sacrificing accuracy. The numerical framework consists of a mixed control volume and finite element formulation, a 'volume of fluid' type method for the interface capturing based on a compressive control volume advection method and second-order finite element methods, and a force-balanced algorithm for the surface tension implementation. Numerical examples of some benchmark tests and the dynamics of liquid jet breakup with and without ambient gas are presented to demonstrate the capability of this method.

  5. A comparative study of sound generation by laminar, combusting and non-combusting jet flows

    NASA Astrophysics Data System (ADS)

    Talei, Mohsen; Brear, Michael J.; Hawkes, Evatt R.

    2014-08-01

    Sound production by two-dimensional, laminar jet flows with and without combustion is studied numerically and theoretically. The compressible Navier-Stokes, energy and progress variable equations are solved by resolving both the near field and the acoustics. The combusting jet flows are compared to non-combusting jets of the same jet Mach number, with the non-combusting, non-isothermal jets having the same steady temperature difference as the combusting jets. This infers that the magnitude of entropic and density disturbances is similar in some of the combusting and non-combusting cases. The flows are perturbed by a sinusoidal inlet velocity fluctuation at different Strouhal numbers. The computational domain is resolved to the far field in all cases, allowing direct examination of the sound radiated and its sources. Lighthill's acoustic analogy is then solved numerically using Green's functions. The radiated sound calculated using Lighthill's equation is in good agreement with that from the simulations for all cases, validating the numerical solution of Lighthill's equation. The contribution of the source terms in Dowling's reformulation of Lighthill's equation is then investigated. It is shown that the source term relating to changes in the momentum of density inhomogeneities is the dominant source term for all non-reacting, non-isothermal cases. Further, this source term has similar magnitude in the combusting cases and is one of the several source terms that have similar magnitude to the source term involving fluctuations in the heat release rate.

  6. Experiment and simulation study of laser dicing silicon with water-jet

    NASA Astrophysics Data System (ADS)

    Bao, Jiading; Long, Yuhong; Tong, Youqun; Yang, Xiaoqing; Zhang, Bin; Zhou, Zupeng

    2016-11-01

    Water-jet laser processing is an internationally advanced technique, which combines the advantages of laser processing with water jet cutting. In the study, the experiment of water-jet laser dicing are conducted with ns pulsed laser of 1064 nm irradiating, and Smooth Particle Hydrodynamic (SPH) technique by AUTODYN software was modeled to research the fluid dynamics of water and melt when water jet impacting molten material. The silicon surface morphology of the irradiated spots has an appearance as one can see in porous formation. The surface morphology exhibits a large number of cavities which indicates as bubble nucleation sites. The observed surface morphology shows that the explosive melt expulsion could be a dominant process for the laser ablating silicon in liquids with nanosecond pulse laser of 1064 nm irradiating. Self-focusing phenomenon was found and its causes are analyzed. Smooth Particle Hydrodynamic (SPH) modeling technique was employed to understand the effect of water and water-jet on debris removal during water-jet laser machining.

  7. Three-dimensional study of turbulent flow characteristics of an offset plane jet with variable density

    NASA Astrophysics Data System (ADS)

    Assoudi, Ali; Habli, Sabra; Mahjoub Saïd, Nejla; Bournot, Hervé; Le Palec, Georges

    2016-11-01

    An experimental and numerical investigation of the flow field of variable density turbulent offset jet is presented. The velocity measurements are performed using a Velocimetry Laser Doppler technique for an offset height h. Three cases of variable-density turbulent plane jets discharging from a rectangular nozzle into a quiescent medium are studied. The variation density jets considered were revealed at different Reynolds numbers. In the second step of this work, a numerical three-dimensional model of the problem is simulated through the resolution of the Navier-Stokes equations by means of the finite volume method and the Reynolds stress model second-order turbulent closure model. A non-uniform mesh system tightened close to the emitting nozzle and both the vertical and horizontal walls is also adopted. A good level of agreement was achieved, between the experiments and the calculations. Once the model validated, our model allowed the evaluation of the influence of the variation density on the characterizing features of the resulting flow filed. It is found that the centerline velocity and concentration of the heavier jet decays much faster than in the two other jets, and a similar behavior for the vertical profiles in the three variable-density jets is well reproduced in the simulation.

  8. Compilation and Review of Supersonic Business Jet Studies from 1963 through 1995

    NASA Technical Reports Server (NTRS)

    Maglieri, Domenic J.

    2011-01-01

    This document provides a compilation of all known supersonic business jet studies/activities conducted from 1963 through 1995 by university, industry and the NASA. First, an overview is provided which chronologically displays all known supersonic business jet studies/activities conducted by universities, industry, and the NASA along with the key features of the study vehicles relative to configuration, planform, operation parameters, and the source of study. This is followed by a brief description of each study along with some comments on the study. Mention will be made as to whether the studies addressed cost, market needs, and the environmental issues of airport-community noise, sonic boom, and ozone.

  9. An experimental study of under-expanded jets

    NASA Astrophysics Data System (ADS)

    Cain, Terrence M.

    1992-10-01

    The results of an experiment conducted in turbulent underexpanded jets of nitrogen and carbon dioxide exhausted into still air from Mach 3 and Mach 5 conical nozzles are reported. The ratio of the stagnation pressure in the nozzle to the static pressure in the receiving tank was of the order 1000 which is a condition representative of rocket exhaust plumes generated at altitudes near 20 km. The Oxford gun tunnel was adapted for the project by attaching a small nozzle to its barrel. Jets were generated in the tunnel's test section, photographed with a schlieren system and traversed by a Pitot probe. The traverse mechanisms developed allow 100 mm travel during the period of 20 ms over which the tunnel stagnation pressure is constant. Methods of increasing this steady period by modification of the tunnel's driver tube are suggested. The characteristics of underexpanded jets are summarized and available experimental data is reviewed and classified using recently published plume similarity parameters. The asymmetrical nature of plumes is discussed and a physical explanation for pulse shock layer instability is given. Condensation of the plume gas is investigated. It is shown that it is unlikely that condensation occurred anywhere within the nitrogen plumes as drop growth rates are negligible at high entropy. Method of characteristics calculations of the initial plume expansion were compared with the Pitot measurements in the plume core. Variation of the nozzle exit conditions used for the boundary conditions of the method of characteristics predictions is used to demonstrate that viscous and two dimensional effects within the nozzle were not very significant in these experiments.

  10. Experimental and Computational Study of Underexpanded Jet Impingement Heat Transfer

    NASA Technical Reports Server (NTRS)

    Rufer, Shann J.; Nowak, Robert J.; Daryabeigi, Kamran; Picetti, Donald

    2009-01-01

    An experiment was performed to assess CFD modeling of a hypersonic-vehicle breach, boundary-layer flow ingestion and internal surface impingement. Tests were conducted in the NASA Langley Research Center 31-Inch Mach 10 Tunnel. Four simulated breaches were tested and impingement heat flux data was obtained for each case using both phosphor thermography and thin film gages on targets placed inside the model. A separate target was used to measure the surface pressure distribution. The measured jet impingement width and peak location are in good agreement with CFD analysis.

  11. Laser induced fluorescence study of free jet expansions

    NASA Astrophysics Data System (ADS)

    Willems, H.; Hulsman, H.; Aerts, F.

    The first part of a sodium seeded free jet expansion (from the orifice to about 20 nozzle diameters downsteam) is illuminated with light from a single mode CW dye laser, and the spatial distribution of the resulting fluorescence is measured. Results for different carrier gases (Ar, Ne, He, N2) and different stagnation pressures (1-20 torr-mm) have been obtained. At the highest stagnation pressures the fluorescence intensity distributions are in good agreement with the prediction from MOC calculations. A qualitative analysis of the deviations at lower stagnation pressures is given.

  12. An Experimental Study of Jet Impingement on a Circular Cylinder.

    DTIC Science & Technology

    1984-08-01

    4, pp. 72--676. 22. Beltaos , S ., and Rajaratnam, N., "Impinging Circular Turbulent Jets," Proceedings of the ASCE Journal of Hydralics Division, Vol...11. CONTRACT OR GRANT NUMBER( s ) 00 Dennis W. Potts ID WI) :-wiFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT. TASK - ANT STUDENT...necessary and identify by block niber) 70.1. AB6S M’AGC - Contlnu* on reverie side If necessary end vdentify by block number) S ATTACH ED [))"~- 1473

  13. Photoreduction of oxoisoaporphines by amines: laser flash and steady-state photolysis, pulse radiolysis, and TD-DFT studies.

    PubMed

    De la Fuente, Julio R; Aliaga, Christian; Poblete, Cristian; Zapata, Gerald; Jullian, Carolina; Saitz, Claudio; Cañete, Alvaro; Kciuk, Gabriel; Sobarzo-Sanchez, Eduardo; Bobrowski, Krzysztof

    2009-07-09

    Photoreduction of oxoisoaporphine (OIA) (1-aza-benzo-[de]anthracen-7-one) and its 5-methoxy (5-MeO-OIA) derivative by selected amines (two non-alpha-hydrogen-donating amines (1,4-diaza[2.2.2]-bicyclooctane (DABCO) and 2,2,6,6-tetramethylpiperidine (TMP)) and three alpha-hydrogen-donating amines (triethylamine (TEA), diethylmethylamine (DEMA), and dimethylethylamine (DMEA))) has been studied in deaerated neat acetonitrile solutions using laser flash and steady-state photolysis. The triplet excited states of OIA and 5-MeO-OIA are characterized by intense absorption maxima located at lambda(max) = 450 nm and lifetimes of 34.7 +/- 0.5 and 44.6 +/- 0.4 micros, respectively. In the presence of tertiary amines, both triplets are quenched with a rate constant that varies from the near diffusion limit (>10(9) M(-1) s(-1)) to a rather low value (approximately 10(7) M(-1) s(-1)) and shows the expected dependence on the reduction potential for one-electron-transfer reactions. The transient absorption spectra observed after quenching of the respective triplet states are characterized by distinct absorption maxima located at lambda(max) = 480 and 490 nm (for OIA and 5-MeO-OIA, respectively) and accompanied by broad shoulders in the range of 510-560 nm. They were assigned to either solvent-separated radical ion pairs and/or isolated radical anions. In the presence of alpha-hydrogen-donating amines these species undergo protonation that leads to the formation of neutral hydrogenated radicals A1H(*)/A2H(*) with two possible sites of protonation, N and O atoms. Pulse radiolysis and molecular modeling together with TD-DFT calculations were used to support the conclusions about the origin of transients.

  14. A Preliminary Study on Sight Word Flash Card Drill: Does It Impact Reading Fluency?

    ERIC Educational Resources Information Center

    Fasko, Sharla N.; Fasko, Daniel, Jr.

    2010-01-01

    Fasko, Jr. Bowling Green State University Abstract The purpose of the study was to assess the effectiveness of a tutoring intervention for sight word acquisition and to examine whether progress was matched by improvement in oral reading fluency. Three primary students were selected based upon teachers' referral for poor reading fluency. Flashcards…

  15. On the start up of supersonic underexpanded jets

    NASA Astrophysics Data System (ADS)

    Lacerda, Nehemias Lima

    An impulsively started jet can be formed by a gas confined in a high pressure reservoir that escapes suddenly through an exit orifice, into a controlled atmosphere. Supersonic gas jets of this type are unsteady and differ from the steady jet that develops later by the presence of a bow shock, a jet head and a nonstationary Mach disk. The effects of the pressure ratio between the high pressure gas inside the reservoir and the lower pressure atmospheric gas, as well as the gas combination used, are studied experimentally. The gases used for the jet and the atmosphere were selected from helium, nitrogen and sulfur hexafluoride. The data acquisition consisted of: high resolution flash photography to obtain detail from the pictures; high-speed movie pictures to obtain the time development of selected features; and fast-response pressure transducers located at the reservoir end plate, the tank end plate and the jet exit. The initial development of the jet is highly time dependent. During this phase, the shape that the jet assumes varies with pressure ratio and with the choice of gas. In particular an extremely light gas exhausting into a heavy atmosphere, exhibits an uncommon shape. It develops as a bubble wrapped by the bow shock, that increases its volume with flow time and pressure ratio. As the pressure ratio increases, it becomes more tightly wrapped by the bow shock. At later times the jet assumes conventional linear growth. After the jet starts, a Mach disk is observed close to the jet exit which moves downstream as the exit pressure builds up. The monotonic increase in exit pressure is caused by the slow breaking of the diaphragm. The position of the Mach disk is furthest from the jet exit when the exit pressure is a maximum. After that it oscillates around the location predicted by the steady theory of Ashkenas and Sherman (1966) at a frequency close to one of the resonant frequencies of the reservoir. The features observed for the inner structure of the jet

  16. Cross-relaxation in nuclear polarization. A flash-CIDNP study

    NASA Astrophysics Data System (ADS)

    Yurkovskaya, A. V.; Tsentalovich, Yu. P.; Sagdeev, R. Z.

    1990-08-01

    CIDNP with microsecond time resolution was used to study the kinetics of nuclear polarization formation during the photolysis of acetone in isopropanol over a wide temperature range. The coincidence of signs of multiplet effects of CIDNP (A/E) for cage and escape reaction products as well as the presence of net polarization (E) changing its sign with decreasing temperature have been revealed. The account of scalar electron-nuclear cross-relaxation has been shown to be necessary for the interpretation of the results obtained.

  17. Flash Point: Evaluation, Experimentation and Estimation

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

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

  18. Oil in Water: An Experimental Study of Splashing and Entrainment from Droplets and Jets

    NASA Astrophysics Data System (ADS)

    Mittal, Raina; Halper, Kristen; Mittal, Rajat

    2015-11-01

    This study is motivated by the interaction between oil and water that is associated with events such as oil spills, oil slicks and underwater oil leaks. For instance, the impact of rain drops on a floating oil slick can lead to the formation of satellite droplets and oil entrainment into the water, that could subsequently lead to further dispersion of the oil slick. Furthermore, the dynamics of high speed jets of oil in water is relevant to underwater oil leaks, but the motion of such oil jets is not well studied. In the current study, we use high-speed videography with various types of commonly available oils to study the impact of water droplets on oil slicks of varying thicknesses. Results show that an oil slick with intermediate thickness leads to the most significant formation of satellite droplets. This behavior seems to be related to the competing effect of oil viscosity and surface tension on the dynamics of splashing. We also use high-speed videography to study the motion and dispersion of underwater oil jets and correlate the breakup of the jet with the inclination of the jet.

  19. Formation of curcumin nanoparticles by flash nanoprecipitation from emulsions.

    PubMed

    Margulis, Katherine; Magdassi, Shlomo; Lee, Han Seung; Macosko, Christopher W

    2014-11-15

    Nanometric particles of a model hydrophobic substance curcumin were prepared by a novel method, namely, flash nanoprecipitation from a coarse oil-in-water emulsion. The method employs turbulent co-mixing of water with curcumin-loaded emulsion using manually-operated confined impingement jets mixer. A clear and stable dispersion of nanoparticles was formed in this process, and could be converted to dry, easily water-dispersible powder by spray drying. The mean size of the particles was about 40 nm by DLS, confirmed by Cryo-TEM. The obtained particles contained 20.4 wt% curcumin, X-ray analysis showed it was amorphous. The significant advantages of the studied process are its feasibility, speed and low cost. It does not require any special high-energy input equipment to reduce the droplet size of the initial emulsion as required by the vast majority of other methods, and relies on rapid turbulent mixing and on flow-induced shear stress formed in the simple, manually-operated mixer. Control experiments clearly indicate that employing emulsion, instead of a plain solution and flash nanoprecipitation instead of a simple antisolvent precipitation are advantageous in terms of particle size and stability.

  20. Flash photolysis and pulse radiolysis studies on collagen Type I in acetic acid solution.

    PubMed

    Sionkowska, Alina

    2006-07-03

    An investigation of the photochemical properties of collagen Type I in acetic acid solution was carried out using nanosecond laser irradiation. The transient spectra of collagen solution excited at 266 nm show two bands. One of them with maximum at 295 nm and the second one with maximum at 400 nm. The peak at 400 nm is assigned to tyrosyl radicals. The first peak of the transient absorption spectra at 295 nm is probably due to photoionisation producing collagen radical cation. The transient for collagen solution in acetic acid at 640 nm was not observed. It is evidence that there is no hydrated electron in the irradiated collagen solution. The reactions of hydrated electrons and (*)OH radicals with collagen have been studied by pulse radiolysis. In the absorption spectra of products resulting from the reaction of collagen with e(aq)(-) no characteristic maximum absorption in UV and visible light region has been observed. In the absorption spectra of products resulting from the reaction of the hydroxyl radicals with collagen two bands have been observed. The first one at 320 nm and the second one at 405 nm. Reaction of (*)OH radicals with tyrosine residues in collagen chains gives rise to Tyr phenoxyl radicals (absorption at 400 nm).

  1. Study of secondary electrons and positrons produced by Terrestrial Gamma-ray Flashes

    NASA Astrophysics Data System (ADS)

    Sarria, D.; Blelly, P.-L.; Forme, F.

    2015-12-01

    Terrestrial Gamma ray Flahes are emissions of X and gamma rays, correlated to thunderstorms. By interacting with the atmosphere, the photons produce a large number of electrons and positrons. Some of these reach altitudes above ˜ 100 km that their interactions with the atmosphere become negligible, and they are then guided by Earth's magnetic field lines, forming the so called Terrestrial Electron Beams. The GBM instrument of the Fermi Space Telescope made a particularly interesting measurement of such an event that happened the 12/09/2009. We perform Monte-Carlo simulations to study this event in detail and we focus on the resulting time histograms. In agreement with previous works, we show that the histogram measured by Fermi GBM can be reproduced from simulations. We then show that the time histogram can be decomposed into three populations of leptons, coming from the hemisphere opposite from the TGF, and mirroring back to the satellite with interactions with the atmosphere or not, and that these we can be clearly distinguished both with their pitch angles.

  2. A flash pyrolysis and petrographic study of cutinite from the Indiana paper coal

    NASA Astrophysics Data System (ADS)

    Nip, Margriet; De Leeuw, J. W.; Schenck, P. A.; Windig, W.; Meuzelaar, H. L. C.; Crelling, J. C.

    1989-03-01

    Samples obtained from the high-volatile bituminous Indiana cuticle-rich and paper coals (Indiana U.S.A.) were investigated by white light and blue light microscopy and by Curie point pyrolysis-mass spectrometry in combination with multivariate data analysis, Curie point pyrolysis-gas chromatography and Curie point pyrolysis-gas chromatographymass spectrometry. Samples obtained from several sites and of different degrees of weathering were analyzed. The macerai cutinite from the same samples was studied as well. The cutinite was concentrated by a standard palynological chemical oxidation technique as well as by density gradient centrifugation. The major constituent of the Indiana paper coal samples appeared to be a recently discovered non-saponifiable polymethylenic biopolymer, present in both recent and fossil plant cuticles. The maceral cutinite is almost exclusively made up of this highly resistant biopolymer. It is shown that upon severe natural weathering this biopolymer, because of its resistance against organic alteration and diagenesis, is relatively enriched and manifests itself in humic coals as the maceral cutinite.

  3. Flight Studies of Problems Pertinent to Low-Speed Operation of Jet Transports

    NASA Technical Reports Server (NTRS)

    Fischel. Jack; Butchart, Stanley P.; Robinson, Glenn H.; Tremant, Robert A.

    1959-01-01

    Flight studies have been made of the low-speed operational regime of jet transports in order to assess potential operating problems. The study was performed utilizing a large multiengine jet airplane having geometric characteristics fairly representative of the jet transports; however, to insure general applicability of the results, the aerodynamic characteristics of the test airplane were varied to simulate a variety of jet-transport airplanes. The specific areas investigated include those of the take-off and landing, and the relation of these maneuvers to the 1 g stall speed and stalling characteristics. The take-off studies included evaluation of the factors affecting the take-off speed and attitude, including the effects of premature rotation and of over-rotation on ground run required. The approach and landing studies pertained to such factors as: desirable lateral-directional damping characteristics; lateral-control requirements; space-positioning limitations during approach under VFR or IFR conditions and requirements for glide-path controls; and evaluation of factors affecting the pilot's choice of landing speeds. Specific recommendations and some indication of desirable characteristics for the jet transports are advanced to alleviate possible operational difficulties or to improve operational performance in the low-speed range.

  4. Numerical Study on Plasma Jet and Particle Behavior in Multi-arc Plasma Spraying

    NASA Astrophysics Data System (ADS)

    Bobzin, K.; Öte, M.; Schein, J.; Zimmermann, S.

    2017-06-01

    Plasma jet and particle behavior in conventional single-arc plasma spraying has been subject to intensive numerical research. However, multi-arc plasma spraying is a different case which has yet to be investigated more closely. Numerical models developed to investigate the characteristics of multi-arc plasma spraying (plasma generator, plasma jet, and plasma-particle interaction models) were introduced in previous publications by the authors. The plasma generator and plasma jet models were already validated by comparing calculated plasma temperatures with results of emission spectroscopic computed tomography. In this study, the above-mentioned models were subjected to further validation effort. Calculated particle in-flight characteristics were compared with those determined by means of particle diagnostics and high-speed videography. The results show very good agreement. The main aim of the current publication is to derive conclusions regarding the general characteristics of plasma jet and particle in-flight behavior in multi-arc plasma spraying. For this purpose, a numerical parameter study is conducted in which the validated models are used to allow variations in the process parameters. Results regarding plasma jet/particle in-flight temperatures and velocities are presented. Furthermore, the general characteristics of plasma jet and particle behavior in multi-arc plasma spraying are discussed and explained. This contributes to better understanding of the multi-arc plasma spraying process, in particular regarding the injection behavior of particles into hot regions of the plasma jet. Finally, an example test case showing a possible practical application area of the models is introduced.

  5. Flash Flood Nowcasting in an Urban Watershed

    NASA Astrophysics Data System (ADS)

    Sharif, H.; Yates, D.; Roberts, R.; Brandes, E.

    2003-04-01

    Flash floods occur when particular meteorological events are combined with certain hydrologic conditions. Several approaches to nowcast flash floods are being developed,> However, predictions of the magnitude and timing of flash flood events is a major challenge. Nowcasts of convective storm events need to be linked with robust hydrologic modeling and analysis in order to produce useful flash flood predictions in terms of timing, and the spatial and temporal distribution of the runoff. Advances in radar-rainfall estimation and two-dimensional physically based runoff modeling offer tools to improve flash flooding forecasting and to reduce the potential for loss of life and property damage in urban catchments. The ability to model extreme hydrologic events in detail was demonstrated using the physically based distributed-parameter hydrologic model GSSHA (Downer and Ogden, 2002) on an urban watershed in Denver, Colorado (Sharif et al., 2002). The study addressed the necessary detail in urban topography and drainage characteristics needed for accurate simulations of urban flood events. With this kind of detailed hydrologic model, accurate short-range meteorological nowcasts (30 60 minutes) would prove useful. Such a nowcast is available from the National Center for Atmospheric Research’s (NCAR) Autonowcaster, a data fusion system that combines several predictor fields with membership functions and weighting schemes to produce automated time and place specific nowcasts of convective rainfall. Predictor fields are derived from characteristics of boundary layer convergence regions, storm characteristics, and dynamic and kinematic attributes of the boundary layer. Simple extrapolations are also used as benchmark nowcasts. The GSSHA model was coupled with the Autonowcaster to produce distributed, physics-based hydrologic predictions in the urban setting. Flash flood predictions of the coupled system are compared to predictions computed using traditional approaches and

  6. An analytical study of the effects of jets located more than one jet diameter above a wing at subsonic speeds

    NASA Technical Reports Server (NTRS)

    Putnam, L. E.

    1974-01-01

    A procedure has been developed for calculating the effects of blowing two jets over a swept tapered wing at low subsonic speeds. The algorithm used is based on a vortex-lattice representation of the wing lifting surface and a line sink-source distribution to simulate the effects of the jet exhaust on the wing lift and drag. The method is limited to those cases in which the jet exhaust does not intersect or wash the wing. The predictions of this relatively simple procedure are in remarkably good agreement with experimentally measured interference lift and interference induced drag.

  7. An analytical study of the effects of jets located more than one jet diameter above a wing at subsonic speeds

    NASA Technical Reports Server (NTRS)

    Putnam, L. E.

    1974-01-01

    A procedure has been developed to calculate the effects of blowing two jets over a swept tapered wing at low subsonic speeds. The algorithm used is based on a vortex lattice representation of the wing lifting surface and a line sink-source distribution to simulate the effects of the jet exhaust on the wing lift and drag. The method is limited to those cases where the jet exhaust does not intersect or wash the wing. The predictions of this relatively simple procedure are in remarkably good agreement with experimentally measured interference lift and interference induced drag.

  8. Hydrodynamic simulations of the core helium flash

    NASA Astrophysics Data System (ADS)

    Mocák, Miroslav; Müller, Ewald; Weiss, Achim; Kifonidis, Konstantinos

    2008-10-01

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

  9. Flash fire propensity of materials

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Cumming, H. J.

    1977-01-01

    Flash fire test results on 86 materials, evaluated using the USF flash fire screening test, are presented. The materials which appear least prone to flash fires are PVC, polyphenylene oxide and sulfide, and polyether and polyaryl sulfone; these did not produce flash fires under these particular test conditions. The principal value of these screening tests at the present time is in identifying materials which appear prone to flash fires, and in identifying which formulations of a generic material are more or less prone to flash fires.

  10. An experimental study of supersonic jet shock-associated noise

    NASA Technical Reports Server (NTRS)

    Nagel, R. T.; Papathansiou, A. G.

    1983-01-01

    A new method of screech tone reduction in underexpanded supersonic jets is utilized to determine if the amplitude of screech is related to the level of shock-associated broadband noise. Acoustic measurements show that as the screech tone is reduced, the broadband shock-associated noise may be increased by up to 4dB at some locations. Several experiments were conducted with disturbances put into the flow upstream of the final contraction. Results from these tests support the concept of linkage between the broadband shock noise and screech tones. Some interesting preliminary results were obtained with a disturbance of the flow at several locations downstream of the nozzle. These results are also discussed.

  11. Convective heat transfer around vertical jet fires: an experimental study.

    PubMed

    Kozanoglu, Bulent; Zárate, Luis; Gómez-Mares, Mercedes; Casal, Joaquim

    2011-12-15

    The convection heat transfer phenomenon in vertical jet fires was experimentally analyzed. In these experiments, turbulent propane flames were generated in subsonic as well as sonic regimes. The experimental data demonstrated that the rate of convection heat transfer increases by increasing the length of the flame. Assuming the solid flame model, the convection heat transfer coefficient was calculated. Two equations in terms of adimensional numbers were developed. It was found out that the Nusselt number attains greater values for higher values of the Rayleigh and Reynolds numbers. On the other hand, the Froude number was analyzed only for the subsonic flames where the Nusselt number grows by this number and the diameter of the orifice.

  12. 14. INTERIOR VIEW, DETAIL OF TRIMMED FLASH; FLASH IS EXCESS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. INTERIOR VIEW, DETAIL OF TRIMMED FLASH; FLASH IS EXCESS METAL EXTRUDED BETWEEN THE DIES USED TO FORGE THE BLADE END OF THE POST HOLE DIGGER - Warwood Tool Company, Foot of Nineteenth Street, Wheeling, Ohio County, WV

  13. An experimental study of dilution and mixing with turbulent jets in crossflows

    NASA Astrophysics Data System (ADS)

    Moawad, Ahmed Kamal

    This thesis is written in the paper format and includes three contributions. The first contribution presents the results of an experimental study on the dilution of circular non-buoyant turbulent surface jets of diameter d, discharged perpendicularly into relatively deep crossflows with depth D in the mixing region. The jet velocity was varied from 2.1 to 12.3 times the velocity of the crossflow. Concentration measurements were carried out as far as x/d = 630, where x is the distance downstream from the nozzle along the crossflow. Minimum dilutions of about 100 were attained in this mixing region. A general correlation has been developed to predict the minimum dilution in terms of the transformed distance /alpha x/d where α is the ratio of the jet to crossflow velocity. The concentration profiles in the vertical and the transverse directions were found to be similar. Expressions were developed to describe the growth of the width and thickness of the deflected jets. The effect of some submergence of the jet nozzle on the minimum dilution was also investigated. The second contribution presents the results of a laboratory study on the mixing characteristics of circular non-buoyant multiple jets discharged into relatively deep river-like crossflows. Experiments were performed for the velocity ratio α varying from 3.5 to 10 where α is the ratio of the jet to that of the crossflow. The concentration profiles in the vertical as well as the lateral directions in the planes of maximum concentration were found to be similar. A minimum dilution up to 80 reached the mixing region. It was found that the minimum dilution decreased with the increase of the velocity ratio α and the increase of the number of ports. Increase of the spacing between ports resulted in a considerable enhancement of the dilution. The trajectory of the multiple jets was identified based on the location of the maximum concentration. The results of an experimental study on rapid mixing and dilution with

  14. Computational study of a contoured plug-nozzle as a supersonic jet noise suppressor

    NASA Technical Reports Server (NTRS)

    Khavaran, A.; Das, A. P.; Das, I.S.

    1996-01-01

    The report summarizes a computational jet noise study of an ideal contoured plug-nozzle (CPN). The gasdynamics of the jet flows have been predicted using the CFD code, NPARC with k-epsilon turbulence model; these data are then used as inputs to perform the noise computations based on the modified version of General Electric MGB code. The study covers a range of operating pressure ratio, 2.0 less than xi less than 5.0 (shockless flow at design pressure ratio, xi(d) = 3.62). The agreement of the computational aeroacoustics results with the available experimental data may be considered to be favorable. The computational results indicate consistent noise reduction effectiveness of the CPN at all operating pressure ratios. At the design pressure ratio (shockless), the codes predict overall sound pressure levels within +3.O dB of the experimental data. But at the off-design pressure ratios (flaws with shocks), the agreement is rather mixed. The theory overpredicts the OASPL's at all pressure ratios except at lower angles to the jet axis in overexpanded mode (xi less than xi(d)), the deviations being within 4.5 dB. The mechanism of shock formations in the CPN jet flows is noted to be basically different from those in the convergent-divergent nozzle jet flows.

  15. Steam-water jet analysis. Final report

    SciTech Connect

    Kashiwa, B.A.; Harlow, F.H.; Demuth, R.B.; Ruppel, H.M.

    1984-05-01

    This report presents the results of a theoretical study on the effects of the steam-water jet emitted from a hypothetical rupture in the high-pressure piping pf a nuclear power plant. A set of calculations is presented, incorporating increasingly complex formulations for mass and momentum exchange between the liquid and vapor flow fields. Comparisons between theory and detailed experimental data are given. The study begins with a thorough evaluation of the specification of equilibrium mass and momentum exchange (homogeneous equilibrium) throughout the flow region, a model that generally overpredicts the rate of jet momentum divergence. The study finds that a near-equilibrium momentum exchange rate and a strongly nonequilibrium momentum exchange rate are needed in the region of large vapor-volume fraction to explain the impingement data for fully developed two-phase jets. This leads to the viewpoint that the large-scale jet is characterized by a flow of large liquid entities that travel relatively unaffected by the strongly diverging vapor flow field. The study also finds circumstances in which a persistent core of metastable superheated water can cause much larger impingement pressures than would otherwise be possible. Existing engineering methods are evaluated for jet-loading predictions in plant design. The existing methods appear to be conservative in most possible rupture circumstances with one exception: when the impingement target is about one pipe-diameter away, large enough to capture the full jet, and the rupture flow area is equal to the full pipe flow area, the existing method can produce loadings that are slightly lower than observed for subcooled, flashing discharge. Recommendations have been made to improve the prediction of existing methods under these conditions.

  16. Protons Trigger Mitochondrial Flashes.

    PubMed

    Wang, Xianhua; Zhang, Xing; Huang, Zhanglong; Wu, Di; Liu, Beibei; Zhang, Rufeng; Yin, Rongkang; Hou, Tingting; Jian, Chongshu; Xu, Jiejia; Zhao, Yan; Wang, Yanru; Gao, Feng; Cheng, Heping

    2016-07-26

    Emerging evidence indicates that mitochondrial flashes (mitoflashes) are highly conserved elemental mitochondrial signaling events. However, which signal controls their ignition and how they are integrated with other mitochondrial signals and functions remain elusive. In this study, we aimed to further delineate the signal components of the mitoflash and determine the mitoflash trigger mechanism. Using multiple biosensors and chemical probes as well as label-free autofluorescence, we found that the mitoflash reflects chemical and electrical excitation at the single-organelle level, comprising bursting superoxide production, oxidative redox shift, and matrix alkalinization as well as transient membrane depolarization. Both electroneutral H(+)/K(+) or H(+)/Na(+) antiport and matrix proton uncaging elicited immediate and robust mitoflash responses over a broad dynamic range in cardiomyocytes and HeLa cells. However, charge-uncompensated proton transport, which depolarizes mitochondria, caused the opposite effect, and steady matrix acidification mildly inhibited mitoflashes. Based on a numerical simulation, we estimated a mean proton lifetime of 1.42 ns and diffusion distance of 2.06 nm in the matrix. We conclude that nanodomain protons act as a novel, to our knowledge, trigger of mitoflashes in energized mitochondria. This finding suggests that mitoflash genesis is functionally and mechanistically integrated with mitochondrial energy metabolism.

  17. VSOP Studies of Internal Structure of the Jet in 3C 273

    NASA Astrophysics Data System (ADS)

    Lobanov, A. P.

    2009-08-01

    Observations with VSOP provided an excellent tool for imaging relativistic flows in great detail. Enhanced resolution and high-dynamic range of VSOP observations enabled resolving internal structure of the parsec-scale jet in 3C 273. This has provided a unique opportunity to determine accurately physical properties of the flow and study the onset and evolution of Kelvin-Helmholtz instability. Several modes of the instability have been identified and traced along the jet, yielding the most detailed picture of the Kelvin-Helmholtz instability developing in a relativistic jet. Exploring and expanding of this area of studies will certainly be further advanced by the next generation space VLBI mission VSOP-2.

  18. Coaxial atomization of a round liquid jet in a high speed gas stream: A phenomenological study

    NASA Astrophysics Data System (ADS)

    Mayer, W. O. H.

    1994-05-01

    Coaxial injectors have proven to be advantageous for the injection, atomization and mixing of propellants in cryogenic H2/O2 rocket engines. Thereby, a round liquid oxygen jet is atomized by a fast, coaxial gaseous hydrogen jet. This article summarizes phenomenological studies of coaxial spray generation under a broad variation of influencing parameters including injector design, inflow, and fluid conditions. The experimental investigations, performed using spark light photography and high speed cinematography in a shadow graph setup as main diagnostic means, illuminate the most important processes leading to atomization. These are identified as turbulence in the liquid jet, surface instability, surface wave growth and droplet detachment. Numerical simulations including free surface flow phenomena are a further diagnostic tool to elucidate some atomization particulars. The results of the study are of general importance in the field of liquid atomization.

  19. An experimental study of the oscillatory flow structure of tone-producing supersonic impinging jets

    NASA Astrophysics Data System (ADS)

    Henderson, Brenda; Bridges, James; Wernet, Mark

    2005-10-01

    An experimental investigation into the structure of a supersonic jet impinging on a large plate is presented. Digital particle image velocimetry (DPIV), shadowgraph photography and acoustic measurements are used to understand the relationship between the unsteady jet structure and the production of tones for nozzle-to-plate spacings between 1 and 5 nozzle exit diameters at a nozzle pressure ratio equal to 4. Results indicate that the instability of the jet depends on the location of the plate in the shock cell structure of the corresponding free jet and the strength of the standoff shock wave, rather than on the occurrence of recirculation zones in the impingement region. Phase-locked studies show streamwise displacements of the stand-off shock wave, a moving recirculation zone in the subsonic flow in front of the plate, and significant oscillations of both the compression and expansion regions in the peripheral supersonic flow when tones are produced. Sound is shown to be generated by periodic pulsing of the wall jet boundary resulting from periodic motion of the flow in the impingement and near-wall regions of the flow.

  20. Flight Studies of Problems Pertinent to High-Speed Operation of Jet Transports

    NASA Technical Reports Server (NTRS)

    Butchart, Stanley P.; Fischel, Jack; Tremant, Robert A.; Robinson, Glenn H.

    1959-01-01

    A flight investigation was made to assess the potential operational problems of jet transports in the transonic cruise range. In this study a large multiengine jet airplane having geometric characteristics fairly representative of the jet transport was used; however, in order to ensure general applicability of the results, the aerodynamic characteristics of the test airplane were varied to simulate a variety of jet- transport airplanes. Some of the specific areas investigated include: (1) an overall evaluation of longitudinal stability and control characteristics at transonic speeds, with an assessment of pitch-up characteristics, (2) the effect of buffeting on airplane operational speeds and maneuvering, (3) the desirable lateral-directional damping characteristics, (4) the desirable lateral-control characteristics, (5) an assessment of over-speed and speed-spread requirements, including the upset maneuver, and (6) an assessment of techniques and airplane characteristics for rapid descent and slow-down. The results presented include pilots' evaluation of the various problem areas and specific recommendations for possible improvement of jet-transport operations in the cruising speed range.

  1. Study of an Atmospheric Pressure Plasma Jet of Argon Generated by Column Dielectric Barrier Discharge

    NASA Astrophysics Data System (ADS)

    Nur, M.; Kinandana, A. W.; Winarto, P.; Muhlisin, Z.; Nasrudin

    2016-11-01

    An atmospheric of argon plasma jet was generated by using column dielectric barrier discharge has been investigated. In this study, argon gas was passed through the capillary column by regulating the flow rate of gas. This atmospheric pressure plasma jet (APPJ) was generated by a sinusoidal AC high voltage in the range of 0.4 kV to 10 kV and at frequencies of 15 kHz and 26 kHz. APPJ has been produced with flow rate of argon gas from 1 litter/min - 10 litters/min. The electric current has been taken with variation of voltage and each interval argon gas flow rate of 1 litter/min. The results show that electric current increase linearly and then it trends to saturation condition by the increasing of applied voltage. We found also that the length of the plasma jet increase by augmenting of applied voltage both for frequencies of 15 kHz and 26 kHz. Furthermore, our results show that length of plasma jet optimum for flow rate of argon gas of 2 litters/minute. In addition, we obtained that the larger applied voltage, the greater the temperature of the plasma jet.

  2. Study of Atomization of a Water Jet by High-Intensity Aerial Ultrasonic Waves

    NASA Astrophysics Data System (ADS)

    Ito, Youichi

    2001-05-01

    An experimental study has been carried out on the atomization of a water jet by aerially radiating it with high-intensity ultrasonic waves. A sound source that enables the linear generation of high-intensity aerial ultrasonic waves (frequency: approximately 20 kHz) is combined with a cylindrical reflection plate in order to create a standing-wave sound field. An attempt has been made to atomize a water jet of 1 mm diameter by passing it through the above sound field at a velocity of approximately 30 m/s. It has been clarified that nodes of sound pressure in the standing-wave sound field are effective for the atomization of a water jet. In addition, the atomizing phenomenon of a water jet has been observed precisely. The relation between the intensity of sound waves required for atomization and the radiation duration has also been clarified. Even the radiation of sound waves for only 2 ms atomizes water. This suggests that a very fast water jet at 300-500 m/s might be atomized.

  3. An Experimental/Modeling Study of Jet Attachment during Counterflow Thrust Vectoring

    NASA Technical Reports Server (NTRS)

    Strykowski, Paul J.

    1997-01-01

    Recent studies have shown the applicability of vectoring rectangular jets using asymmetrically applied counterflow in the presence of a short collar. This novel concept has applications in the aerospace industry where counterflow can be used to vector the thrust of a jet's exhaust, shortening take-off and landing distances and enhancing in-flight maneuverability of the aircraft. Counterflow thrust vectoring, 'CFTV' is desirable due to its fast time response, low thrust loss, and absence of moving parts. However, implementation of a CFTV system is only possible if bistable jet attachment can be prevented. This can be achieved by properly designing the geometry of the collar. An analytical model is developed herein to predict the conditions under which a two-dimensional jet will attach to an offset curved wall. Results from this model are then compared with experiment; for various jet exit Mach numbers, collar offset distances, and radii of curvature. Their excellent correlation permits use of the model as a tool for designing a CFTV system.

  4. Study of laser-created laboratory plasma jets with soft x-ray laser interferometry

    NASA Astrophysics Data System (ADS)

    Grava, Jonathan; Purvis, Michael; Filevich, Jorge; Marconi, Mario; Rocca, Jorge; Dunn, James; Moon, Stephen; Shlyaptsev, Vyacheslav

    2008-04-01

    Jet-like plasma structures were generated by irradiating V-shaped Al targets at I=1x10^12 W/cm^2 with 0.8 J Ti:Sa laser pulses of 120 ps duration. A narrow plasma plume was observed to expand from the bottom of the cavity with Mach number ˜ 5. The plasma jet evolution was studied using soft x-ray laser interferometry (λ= 46.9 nm), allowing electron density measurements of the 1-mm plasma that exceeded 1x10^20 cm-3. Late in the evolution the jet expands laterally and develops sidelobes as it interacts with additional material expanding from the walls. The measurements were compared with 2-D simulations from the code HYDRA to gain understanding of the mechanisms that form the narrow plasma jet, including the role of radiation cooling. Measurements of similar jets generated by irradiating targets of different Z are under way Work sponsored by NNSA-SSAA DOE Grant # DE-FG52-060NA26152 and the U.S. DOE LLNL through ILSA contract No. W-7405-Eng-48.

  5. An experimental burn wound-healing study of non-thermal atmospheric pressure microplasma jet arrays.

    PubMed

    Lee, Ok Joo; Ju, Hyung Woo; Khang, Gilson; Sun, Peter P; Rivera, Jose; Cho, Jin Hoon; Park, Sung-Jin; Eden, J Gary; Park, Chan Hum

    2016-04-01

    In contrast with a thermal plasma surgical instrument based on coagulative and ablative properties, low-temperature (non-thermal) non-equilibrium plasmas are known for novel medicinal effects on exposed tissue while minimizing undesirable tissue damage. In this study we demonstrated that arrays of non-thermal microplasma jet devices fabricated from a transparent polymer can efficiently inactivate fungi (Candida albicans) as well as bacteria (Escherichia coli), both in vitro and in vivo, and that this leads to a significant wound-healing effect. Microplasma jet arrays offer several advantages over conventional single-jet devices, including superior packing density, inherent scalability for larger treatment areas, unprecedented material flexibility in a plasma jet device, and the selective generation of medically relevant reactive species at higher plasma densities. The therapeutic effects of our multi-jet device were verified on second-degree burns in animal rat models. Reduction of the wound area and the histology of the wound after treatment have been investigated, and expression of interleukin (IL)-1α, -6 and -10 was verified to evaluate the healing effects. The consistent effectiveness of non-thermal plasma treatment has been observed especially in decreasing wound size and promoting re-epithelialization through collagen arrangement and the regulation of expression of inflammatory genes.

  6. Alveolar recruitment of atelectasis under combined high-frequency jet ventilation: a computed tomography study.

    PubMed

    Kraincuk, Paul; Körmöczi, Günther; Prokop, Mathias; Ihra, Gerald; Aloy, Alexander

    2003-08-01

    To quantify the effect of superimposed high-frequency jet ventilation on lung recruitment in adult patients with acute lung injury. Prospective clinical study in the intensive care unit of a university teaching hospital. Eight adults suffering from acute lung injury with a mean lung injury score of 2.6+/-0.6 and pronounced atelectasis in at least two lung quadrants. The cause was either pneumonia ( n=5) or postoperative sepsis ( n=3). Superimposed high-frequency jet ventilation was initiated in patients following a mean of 4.4+/-1.7 days of conventional ventilation. Before and 4 h after the start of superimposed high-frequency jet ventilation differential lung volumes were determined by volumetry using computed tomography. Superimposed high-frequency jet ventilation significantly increased the lung volume of every patient due to alveolar recruitment. This was achieved despite lower peak inspiratory pressures and higher PaO(2)/FIO(2) ratios than with conventional ventilation. Treatment with superimposed high-frequency jet ventilation for 4 h resulted in rapid alveolar recruitment in dependent lung areas, improved gas exchange, and better arterial oxygenation. It offers an effective and advantageous alternative to conventional ventilation for ventilatory management of respiratory insufficient patients.

  7. Relationship between objectively recorded hot flashes and sleep disturbances among breast cancer patients: investigating hot flash characteristics other than frequency.

    PubMed

    Savard, Marie-Hélène; Savard, Josée; Caplette-Gingras, Aude; Ivers, Hans; Bastien, Célyne

    2013-10-01

    The aim of this study was to evaluate the relationship between various characteristics of objectively recorded hot flashes and sleep disturbances in breast cancer patients. Fifty-six women who had completed a similar treatment protocol for a first diagnosis of breast cancer within the previous 3 months wore ambulatory sternal skin conductance and polysomnography devices for a home-based nighttime recording of hot flashes and sleep. Hot flash frequency was not associated with polysomnographic variables (r = -0.18 to 0.21) or beta-I and beta-II electroencephalographic activities (r = -0.01 and 0.03) but was significantly correlated with increased slow (r = 0.28) and delta (r = 0.32) electroencephalographic activities. A slower hot flash onset and a longer hot flash duration were associated with greater polysomnographic impairments (r = -0.50 to 0.48). Greater sleep disturbances were found during hot flash onset or hot flash plateau as compared with the pre-hot flash period (greater percentage of wake time, lower percentage of stage II sleep, and lower percentage of rapid eye movement sleep, all P values < 0.05). The probability that a stage change to a lighter sleep occurred was significantly greater during hot flash onset (11%) than during hot flash plateau (6%; P = 0.02). This study suggests that the speed and duration of hot flashes would contribute more importantly to sleep alterations than hot flash frequency. Sleep disturbances tend to occur simultaneously with hot flashes, suggesting that these two nocturnal symptoms are manifestations of a higher-order mechanism involving the central nervous system.

  8. Studies of jet quenching using isolated-photon + jet correlations in PbPb and pp collisions at √{sNN} = 2.76 TeV

    NASA Astrophysics Data System (ADS)

    Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Fabjan, C.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hammer, J.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Liko, D.; Mikulec, I.; Pernicka, M.; Rahbaran, B.; Rohringer, C.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Taurok, A.; Wagner, P.; Waltenberger, W.; Walzel, G.; Widl, E.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Bansal, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Luyckx, S.; Maes, T.; Mucibello, L.; Ochesanu, S.; Roland, B.; Rougny, R.; Selvaggi, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Blekman, F.; Blyweert, S.; D'Hondt, J.; Gonzalez Suarez, R.; Kalogeropoulos, A.; Maes, M.; Olbrechts, A.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Villella, I.; Charaf, O.; Clerbaux, B.; De Lentdecker, G.; Dero, V.; Gay, A. P. R.; Hreus, T.; Léonard, A.; Marage, P. E.; Reis, T.; Thomas, L.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Adler, V.; Beernaert, K.; Cimmino, A.; Costantini, S.; Garcia, G.; Grunewald, M.; Klein, B.; Lellouch, J.; Marinov, A.; Mccartin, J.; Ocampo Rios, A. A.; Ryckbosch, D.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Vanelderen, L.; Verwilligen, P.; Walsh, S.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Bruno, G.; Castello, R.; Ceard, L.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Lemaitre, V.; Liao, J.; Militaru, O.; Nuttens, C.; Pagano, D.; Pin, A.; Piotrzkowski, K.; Schul, N.; Vizan Garcia, J. M.; Beliy, N.; Caebergs, T.; Daubie, E.; Hammad, G. H.; Alves, G. A.; Correa Martins Junior, M.; De Jesus Damiao, D.; Martins, T.; Pol, M. E.; Souza, M. H. G.; Aldá Júnior, W. L.; Carvalho, W.; Custódio, A.; Da Costa, E. M.; De Oliveira Martins, C.; Fonseca De Souza, S.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Oguri, V.; Prado Da Silva, W. L.; Santoro, A.; Silva Do Amaral, S. M.; Soares Jorge, L.; Sznajder, A.; Bernardes, C. A.; Dias, F. A.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Lagana, C.; Marinho, F.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Genchev, V.; Iaydjiev, P.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Tcholakov, V.; Trayanov, R.; Vutova, M.; Dimitrov, A.; Hadjiiska, R.; Kozhuharov, V.; Litov, L.; Pavlov, B.; Petkov, P.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Jiang, C. H.; Liang, D.; Liang, S.; Meng, X.; Tao, J.; Wang, J.; Wang, X.; Wang, Z.; Xiao, H.; Xu, M.; Zang, J.; Zhang, Z.; Asawatangtrakuldee, C.; Ban, Y.; Guo, S.; Guo, Y.; Li, W.; Liu, S.; Mao, Y.; Qian, S. J.; Teng, H.; Wang, S.; Zhu, B.; Zou, W.; Avila, C.; Gomez Moreno, B.; Osorio Oliveros, A. F.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Plestina, R.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Duric, S.; Kadija, K.; Luetic, J.; Morovic, S.; Attikis, A.; Galanti, M.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Finger, M.; Finger, M.; Assran, Y.; Elgammal, S.; Ellithi Kamel, A.; Khalil, S.; Mahmoud, M. A.; Radi, A.; Kadastik, M.; Müntel, M.; Raidal, M.; Rebane, L.; Tiko, A.; Azzolini, V.; Eerola, P.; Fedi, G.; Voutilainen, M.; Härkönen, J.; Heikkinen, A.; Karimäki, V.; Kinnunen, R.; Kortelainen, M. J.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Ungaro, D.; Wendland, L.; Banzuzi, K.; Korpela, A.; Tuuva, T.; Besancon, M.; Choudhury, S.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Millischer, L.; Nayak, A.; Rander, J.; Rosowsky, A.; Shreyber, I.; Titov, M.; Baffioni, S.; Beaudette, F.; Benhabib, L.; Bianchini, L.; Bluj, M.; Broutin, C.; Busson, P.; Charlot, C.; Daci, N.; Dahms, T.; Dobrzynski, L.; Granier de Cassagnac, R.; Haguenauer, M.; Miné, P.; Mironov, C.; Ochando, C.; Paganini, P.; Sabes, D.; Salerno, R.; Sirois, Y.; Veelken, C.; Zabi, A.; Agram, J.-L.; Andrea, J.; Bloch, D.; Bodin, D.; Brom, J.-M.; Cardaci, M.; Chabert, E. C.; Collard, C.; Conte, E.; Drouhin, F.; Ferro, C.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Juillot, P.; Karim, M.; Le Bihan, A.-C.; Van Hove, P.; Fassi, F.; Mercier, D.; Beauceron, S.; Beaupere, N.; Bondu, O.; Boudoul, G.; Brun, H.; Chasserat, J.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Kurca, T.; Lethuillier, M.; Mirabito, L.; Perries, S.; Sordini, V.; Tosi, S.; Tschudi, Y.; Verdier, P.; Viret, S.; Tsamalaidze, Z.; Anagnostou, G.; Beranek, S.; Edelhoff, M.; Feld, L.; Heracleous, N.; Hindrichs, O.; Jussen, R.; Klein, K.; Merz, J.; Ostapchuk, A.; Perieanu, A.; Raupach, F.

    2013-01-01

    Results from the first study of isolated-photon + jet correlations in relativistic heavy ion collisions are reported. The analysis uses data from PbPb collisions at a centre-of-mass energy of 2.76 TeV per nucleon pair corresponding to an integrated luminosity of 150 μb-1 recorded by the CMS experiment at the LHC. For events containing an isolated photon with transverse momentum pTγ > 60 GeV / c and an associated jet with pTJet > 30 GeV / c, the photon + jet pT imbalance is studied as a function of collision centrality and compared to pp data and PYTHIA calculations at the same collision energy. Using the pTγ of the isolated photon as an estimate of the momentum of the associated parton at production, this measurement allows an unbiased characterisation of the in-medium parton energy loss. For more central PbPb collisions, a significant decrease in the ratio pTJet / pTγ relative to that in the PYTHIA reference is observed. Furthermore, significantly more pTγ > 60 GeV / c photons in PbPb are observed not to have an associated pTJet > 30 GeV / c jet, compared to the reference. However, no significant broadening of the photon + jet azimuthal correlation is observed.

  9. Onset conditions for flash sintering of UO2

    DOE PAGES

    Raftery, Alicia M.; Pereira da Silva, João Gustavo; Byler, Darrin D.; ...

    2017-06-22

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

  10. Onset conditions for flash sintering of UO2

    NASA Astrophysics Data System (ADS)

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

    2017-09-01

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

  11. Flash Flood Case Study for Istanbul City Region Using the Combined WRF-Noah and Hydrological Modeling System HEC-HMS

    NASA Astrophysics Data System (ADS)

    Sirdas, S.-; Ilter, M.-

    2012-12-01

    The big losses that occur due to events in Flood emphasized the importance of unplanned urbanization. Global temperature change of the last fifty years has increased the importance of water catchment basins. Istanbul is one of the most populous areas in the Marmara Region. After 2000, in the Marmara region results in loss of life and property of the two major flood occurred. In this study, in the floods in 2007 and 2009 were analyzed with the hydrological model. In this study, Istanbul is examined the current situation in terms of floods and flood probabilities calculated which tried to repeat itself. Marmara Region, which is included in the study, 14 automated weather station data obtained from General Directorate of Meteorology were used for the analyzes of these data. Data 1970 - 2010 periods included between the values of the current rainfall. These values are calculated daily, monthly and annual analyzes were carried out. According to the analysis examined whether there is a connection between the stations. Which are necessary for flood analysis provides information on geographic location and topography, soil structure existing in the region, slope, and infiltration rate were taken into consideration. WRF/ARW model is utilized for mesoscale forecasts at a high resolution and included optimum physical parameterizations which are selected in order to remove microphysics, cumulus, land surface and planetary boundary layer bias errors of forecasts. WRF-Noah physics options are selected for flash flood case and convective precipitation. One examination of heavy flash flood occurred over Istanbul region on September 9, 2009. Precipitation pattern and precipitable water amount evaluated for Istanbul region. The goal of this study is to provide forecasts of various fields at a horizontal resolution of 5 km and at a temporal resolution of every three hours. The ultimate goal of this forecast is to provide a useful state of the art mesoscale forecasts for the flash

  12. Parallel data analysis in a multichannel flash-ADC-system

    SciTech Connect

    Eckerlin, G.; Elsen, E.; Schmitt, H.V.D.; Wagner, A.; Walter, P.V.; Zimmer, M.

    1987-02-01

    Parallel analysis of drift chamber signals with M68000 processors has proven to be an efficient way to deal with the tremendous data flow generated by high speed (100 MHz) Flash-ADCs in real time. The authors report on the experience gained with a network of 34 processors, placed in 3 VME crates, to read out the 3072 Flash-ADC channels of the JADE Jet-Chamber at PETRA (1). The properties of such a system are compared to more conventional readout schemes for drift chambers.

  13. A Experimental Study of the Velocity Field of a Transverse Jet Injected Into a Supersonic Crossflow.

    NASA Astrophysics Data System (ADS)

    Santiago, Juan Gabriel

    The design of a supersonic combustor which uses transverse jet injection into a supersonic flow (TJISF) as a means of fuel injection and mixing requires a fundamental understanding of these flows. Such knowledge may also serve studies of the thrust vector control of rocket nozzles, the cooling of nozzle walls, and jet reaction force prediction. The present investigation is a quantitative, experimental study of a single, sonic, underexpanded, transverse jet injected into a Mach 1.6 crossflow. The motivation for this research program is to improve the fundamental understanding of the fluid dynamic mechanisms and mixing processes in this flow. Schlieren/shadowgraph photography, surface flow visualization, and two-component, frequency pre-shifted laser Doppler velocimetry (LDV) data have been obtained. Four LDV optical arrangements have been used to measure all three mean velocity components, five of the six kinematic Reynolds stresses, and the turbulent kinetic energy. The LDV system is equipped with a computer-controlled traverse system and has been used to provide velocity measurements at over 4,000 locations throughout the TJISF flowfield. The study focuses on the transverse, midline plane and two crossflow planes. The majority of the measurements in these planes has been made in the high gradient regions of the jet plume. Measurements of the mean and turbulent velocity fields helped resolve important issues in the study of the TJISF flowfield. These issues include the size and orientation of the recirculation regions upstream and downstream of the jet (including the horseshoe vortex just upstream of the jet); the structure and strength of the bow shock, barrel shock, and Mach disk; the structure, strength, and development of the kidney-shaped, counter-rotating vortex pair; the growth of the annular shear layer between the jet plume and the crossflow; the growth of the boundary layer beneath the jet plume; the Reynolds stress fields of the flow; the production of

  14. Numerical and experimental study on a pulsed-dc plasma jet

    NASA Astrophysics Data System (ADS)

    Liu, X. Y.; Pei, X. K.; Lu, X. P.; Liu, D. W.

    2014-06-01

    A numerical and experimental study of plasma jet propagation in a low-temperature, atmospheric-pressure, helium jet in ambient air is presented. A self-consistent, multi-species, two-dimensional axially symmetric plasma model with detailed finite-rate chemistry of helium-air mixture composition is used to provide insights into the propagation of the plasma jet. The obtained simulation results suggest that the sheath forms near the dielectric tube inner surface and shields the plasma channel from the tube surface. The strong electric field at the edge of the dielectric field enhances the ionization in the air mixing layer; therefore, the streamer head becomes ring-shaped when the streamer runs out of the tube. The avalanche-to-streamer transition is the main mechanism of streamer advancement. Penning ionization dominates the ionization reactions and increases the electrical conductivity of the plasma channel. The simulation results are supported by experimental observations under similar discharge conditions.

  15. Oxygen and Fuel Jet Diffusion Flame Studies in Microgravity Motivated by Spacecraft Oxygen Storage Fire Safety

    NASA Technical Reports Server (NTRS)

    Sunderland, P. B.; Yuan, Z.-G.; Krishnan, S. S.; Abshire, J. M.; Gore, J. P.

    2003-01-01

    Owing to the absence of past work involving flames similar to the Mir fire namely oxygen-enhanced, inverse gas-jet diffusion flames in microgravity the objectives of this work are as follows: 1. Observe the effects of enhanced oxygen conditions on laminar jet diffusion flames with ethane fuel. 2. Consider both earth gravity and microgravity. 3. Examine both normal and inverse flames. 4. Compare the measured flame lengths and widths with calibrated predictions of several flame shape models. This study expands on the work of Hwang and Gore which emphasized radiative emissions from oxygen-enhanced inverse flames in earth gravity, and Sunderland et al. which emphasized the shapes of normal and inverse oxygen-enhanced gas-jet diffusion flames in microgravity.

  16. An experimental and numerical study of particle-laden coaxial jet flows

    NASA Technical Reports Server (NTRS)

    Mostafa, A. A.; Mongia, H. C.; Mcdonell, V. G.; Samuelsen, G. S.

    1990-01-01

    A detailed experimental and numerical study of the developing region of coaxial jet flows with and without glass beads is performed. A two-component phase/Doppler interferometer is used to measure mean and fluctuating velocity components for each phase and particle-number density. The numerical calculation is based on a stochastic Lagrangian treatment for the particles and a recently proposed two-equation turbulence model for two-phase flows. Results show that the particle-number density profile becomes narrower than the corresponding profile for round jet flow and that the particles attain a uniform velocity across the jet radius. The particles attenuate the level of gas turbulence and increase their anisotropy level. The numerical calculations yield reasonable and encouraging agreement with the measurements.

  17. A visual study in the near field of turbulent jets and implications for estimating accidental discharges

    NASA Astrophysics Data System (ADS)

    Savaş, Ö.

    2012-11-01

    A series of dye flow visualization experiments are carried out in water to study the visible flow features in the near field of turbulent jets and to assess their usefulness in estimating the discharge rate of a turbulent jet in a homogeneous medium. The jet Reynolds numbers are 0.3-2.2 × 105. The large eddies at the core of the flow and the smaller eddies at the edge show disparate, independent length scales. Their convection speeds are more than an order of magnitude apart. Discharge rate estimates based on large-scale core features are useful. However, their reliability depends on a priori knowledge of the state of the bulk flow upstream of the discharge location. A useful method for estimating discharge rates based on the small-scale outer edge features is not obvious.

  18. A study of reacting free and ducted hydrogen/air jets

    NASA Technical Reports Server (NTRS)

    Beach, H. L., Jr.

    1975-01-01

    The mixing and reaction of a supersonic jet of hydrogen in coaxial free and ducted high temperature test gases were investigated. The importance of chemical kinetics on computed results, and the utilization of free-jet theoretical approaches to compute enclosed flow fields were studied. Measured pitot pressure profiles were correlated by use of a parabolic mixing analysis employing an eddy viscosity model. All computations, including free, ducted, reacting, and nonreacting cases, use the same value of the empirical constant in the viscosity model. Equilibrium and finite rate chemistry models were utilized. The finite rate assumption allowed prediction of observed ignition delay, but the equilibrium model gave the best correlations downstream from the ignition location. Ducted calculations were made with finite rate chemistry; correlations were, in general, as good as the free-jet results until problems with the boundary conditions were encountered.

  19. An experimental and numerical study of particle-laden coaxial jet flows

    NASA Technical Reports Server (NTRS)

    Mostafa, A. A.; Mongia, H. C.; Mcdonell, V. G.; Samuelsen, G. S.

    1990-01-01

    A detailed experimental and numerical study of the developing region of coaxial jet flows with and without glass beads is performed. A two-component phase/Doppler interferometer is used to measure mean and fluctuating velocity components for each phase and particle-number density. The numerical calculation is based on a stochastic Lagrangian treatment for the particles and a recently proposed two-equation turbulence model for two-phase flows. Results show that the particle-number density profile becomes narrower than the corresponding profile for round jet flow and that the particles attain a uniform velocity across the jet radius. The particles attenuate the level of gas turbulence and increase their anisotropy level. The numerical calculations yield reasonable and encouraging agreement with the measurements.

  20. An experimental study of the structure and acoustic field of a jet in a cross stream

    NASA Technical Reports Server (NTRS)

    Camelier, I.; Karamcheti, K.; Hodder, B.

    1975-01-01

    The investigation reported is related to studies of the noise generated by a lifting jet in forward motion such as in the case of a V/STOL aircraft. The investigation involved experiments in a subsonic wind tunnel. The two-microphone cross-correlation method used for measuring the acoustic intensity provides data concerning the noise directly radiated from the source, practically free from any reflection effects. The theoretical basis of the two-microphone method is discussed along with the experimental apparatus, the characteristics of the flow inside the jet, and the features of the acoustic field.

  1. Application of optical methods to the study of jet noise and turbulence

    NASA Technical Reports Server (NTRS)

    Sava, P. G.; Haertig, J.

    1980-01-01

    Optical methods are generally applied in fluid mechanics for either visualization or measurement. The use of a laser anemometer to study flow velocity in a jet and its relaton to the sound radiated is described. The same acoustic emission phenomenon is also measued by combining the signals from four Schlieren systems with that from an interferometer. The use of an optical Fourier transformation approach with real time analysis to determine the spatio-temporal structure of a field of mass volume such as a waveguide or free jet is also examined.

  2. Triplet excitation dynamics of two keto-carotenoids in n-hexane and in methanol as studied by ns flash photolysis spectroscopy

    NASA Astrophysics Data System (ADS)

    Li, Li; Hu, Feng; Chang, Yu-Qiang; Zhou, Yan; Wang, Peng; Zhang, Jian-Ping

    2015-07-01

    Siphonaxanthin and siphonein are two keto-carotenoids. Upon anthracene-sensitizing, triplet excitation dynamics of these two carotenoids were studied in n-hexane and in methanol, respectively, by ns flash photolysis spectroscopy. In n-hexane, bleaching of the ground state absorption (GSB) and the excitation triplet (3Car*) absorption were observed. In methanol, upon the decay of the 3Car*, the cation dehydrodimer of carotenoid, #[Car]2+, generated by the same rate, while an additional GSB generated synchronously, a polar solvent assisted and anthracene-sensitized mechanism was addressed based on the discussion. The environment-sensitive triplet excitation dynamics imply their potential role in photo-protection in vivo.

  3. A flash-photolysis electron spin resonance study of radicals formed from carboxylic acids; exchange effects in spin-polarized radicals

    NASA Astrophysics Data System (ADS)

    McLauchlan, K. A.; Ritchie, A. J. D.

    The time-integration spectroscopy (TIS) technique has been applied to the study of transient radicals created by flash photolysis of solutions of benzene-1,2,4,5-tetracarboxylic acid (pyromellitic acid), benzene-1,2,-dicarboxylic acid (phthalic acid) and benzene-1,4-dicarboxylic acid (terephthalic acid). In these systems electron transfer, proton transfer and rotational isomerism all affect the spin-polarized spectra observed. The exchange processes are analysed theoretically, in the case of proton exchange for the first time in the polarized situation, and it is shown that the two different exchange processes can be simply differentiated in the time-dependent TIS spectra.

  4. Flash flood events recorded by air temperature changes in caves: A case study in Covadura Cave (SE Spain)

    NASA Astrophysics Data System (ADS)

    Gázquez, Fernando; Calaforra, José María; Fernández-Cortés, Ángel

    2016-10-01

    On 28th September 2012, more than 150 mm rain fell in just two hours in some points of southeastern Spain, triggering intense flash floods that resulted in the death of ten people and widespread material damage. In the gypsum karst of Sorbas, rainfall intensity reached 33 mm/h. Air temperature monitoring in different levels of Covadura Cave, down to 85 m depth, enabled the effect of this extreme episode on the cave microclimate to be evaluated in real time. The cave air temperature increased by between 0.9 and 4.1 °C as a result of water flow into the cavity and intense mixing of air masses, in addition to the displacement of deeper air masses toward shallower levels produced by fast recharge of the surrounding karst aquifer. The lag between peak rainfall intensity and the highest cave air temperature was 5-6 h, indicating the response time of the karst to this rainfall event. No trends with depth were observed, suggesting that water not only flowed in through the main cave entrance but also through secondary accesses and fractures. Furthermore, the size of the cave passages and the intensity of air turbulence generated by waterfalls in the cave played an important role in producing these temperature differences. Even though the rainfall event lasted 10 h, cave air temperature did not return to pre-flash flood values until more than 20 days later. This indicates that, while waterflow through the cave might stop a few hours after the rainfall event, cave air temperature can be affected over a longer period. This can be explained by slow groundwater level decreasing of the surrounding karst aquifer and latent heat liberation produced by moisture condensation on the cave walls. Our results show how continuous monitoring of air temperature in caves can be a useful tool for evaluating the short-term effects of flash floods in subterranean karst systems.

  5. Experimental Study of an Inclined Jet-In-Cross-Flow Interacting with a Vortex Generator

    NASA Technical Reports Server (NTRS)

    Zaman, K. B. M. Q.; Rigby, D. L.; Heidmann, J. D.

    2010-01-01

    An experiment is conducted on the effectiveness of a vortex generator (VG) in preventing lift-off of a jet-in-cross-flow (JICF), with film-cooling application in mind. The jet issues into the boundary layer at an angle of 20 to the free-stream. The effect of a triangular ramp-sha