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Sample records for hydrazine engine plume

  1. Monomethylhydrazine versus hydrazine fuels - Test results using a 100 pound thrust bipropellant rocket engine

    Science.gov (United States)

    Smith, J. A.; Stechman, R. C.

    1981-01-01

    A test program was performed to evaluate hydrazine (N2H4) as a fuel for a 445 Newton (100 lbf) thrust bipropellant rocket engine. Results of testing with an identical thruster utilizing monomethylhydrazine (MMH) are included for comparison. Engine performance with hydrazine fuel was essentially identical to that experienced with monomethylhydrazine although higher combustor wall temperatures (approximately 400 F) were obtained with hydrazine. Results are presented which indicate that hydrazine as a fuel is compatible with Marquardt bipropellant rocket engines which use monomethylhydrazine as a baseline fuel.

  2. Hydrocarbon Rocket Engine Plume Imaging with Laser Induced Incandescence Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA/ Marshall Space Flight Center (MSFC) needs sensors that can be operated on rocket engine plume environments to improve NASA/SSC rocket engine performance. In...

  3. Plume aerodynamic effects of cushion engine in lunar landing

    Institute of Scientific and Technical Information of China (English)

    He Bijiao; He Xiaoying; Zhang Mingxing; Cai Guobiao

    2013-01-01

    During the second period of China “Tanyue” Project,the explorer will softland on the moon.The cushion engines are used to decelerate the explorer and reduce the impact on the lunar ground.It is necessary to study its plume effects on the explorer component.The self-developed PWS (Plume WorkStation) software based on direct simulation Monte Carlo (DSMC) method is used to simulate the plume effects of two 150 N engines.Due to the complex structure of the explorer,PWS uses a decoupling method to treat the boundary mesh,which mainly interacts with simulation particles,and has no relation with the computational grids.After the analytical expressions of plane surfaces and curved surfaces of each boundary block are given,the particle position within or without the boundary blocks can be easily determined.Finally the 3D plume field of two 150 N engines is simulated.The pressure,temperature and velocity distributions of plume field are clearly presented by three characteristic slices.The aerodynamic effects on the explorer bottom,the landfall legs and antenna are separately shown.The compression influence on the plume flow of four landfall legs can be observed.

  4. An expert system for spectroscopic analysis of rocket engine plumes

    Science.gov (United States)

    Reese, Greg; Valenti, Elizabeth; Alphonso, Keith; Holladay, Wendy

    The expert system described in this paper analyzes spectral emissions of rocket engine exhaust plumes and shows major promise for use in engine health diagnostics. Plume emission spectroscopy is an important tool for diagnosing engine anomalies, but it is time-consuming and requires highly skilled personnel. The expert system was created to alleviate such problems. The system accepts a spectral plot in the form of wavelength vs intensity pairs and finds the emission peaks in the spectrum, lists the elemental emitters present in the data and deduces the emitter that produced each peak. The system consists of a conventional language component and a commercially available inference engine that runs on an Apple Macintosh computer. The expert system has undergone limited preliminary testing. It detects elements well and significantly decreases analysis time.

  5. Ion Engine Plume Interaction Calculations for Prototypical Prometheus 1

    Science.gov (United States)

    Mandell, Myron J.; Kuharski, Robert A.; Gardner, Barbara M.; Katz, Ira; Randolph, Tom; Dougherty, Ryan; Ferguson, Dale C.

    2005-01-01

    Prometheus 1 is a conceptual mission to demonstrate the use of atomic energy for distant space missions. The hypothetical spacecraft design considered in this paper calls for multiple ion thrusters, each with considerably higher beam energy and beam current than have previously flown in space. The engineering challenges posed by such powerful thrusters relate not only to the thrusters themselves, but also to designing the spacecraft to avoid potentially deleterious effects of the thruster plumes. Accommodation of these thrusters requires good prediction of the highest angle portions of the main beam, as well as knowledge of clastically scattered and charge exchange ions, predictions for grid erosion and contamination of surfaces by eroded grid material, and effects of the plasma plume on radio transmissions. Nonlinear interactions of multiple thrusters are also of concern. In this paper we describe two- and three-dimensional calculations for plume structure and effects of conceptual Prometheus 1 ion engines. Many of the techniques used have been validated by application to ground test data for the NSTAR and NEXT ion engines. Predictions for plume structure and possible sputtering and contamination effects will be presented.

  6. Plume spectrometry for liquid rocket engine health monitoring

    Science.gov (United States)

    Powers, William T.; Sherrell, F. G.; Bridges, J. H., III; Bratcher, T. W.

    1988-01-01

    An investigation of Space Shuttle Main Engine (SSME) testing failures identified optical events which appeared to be precursors of those failures. A program was therefore undertaken to detect plume trace phenomena characteristic of the engine and to design a monitoring system, responsive to excessive activity in the plume, capable of delivering a warning of an anomalous condition. By sensing the amount of extraneous material entrained in the plume and considering engine history, it may be possible to identify wearing of failing components in time for a safe shutdown and thus prevent a catastrophic event. To investigate the possibilities of safe shutdown and thus prevent a monitor to initiate the shutdown procedure, a large amount of plume data were taken from SSME firings using laboratory instrumentation. Those data were used to design a more specialized instrument dedicated to rocket plume diagnostics. The spectral wavelength range of the baseline data was about 220 nanometers (nm) to 15 micrometer with special attention given to visible and near UV. The data indicates that a satisfactory design will include a polychromator covering the range of 250 nM to 1000 nM, along with a continuous coverage spectrometer, each having a resolution of at least 5A degrees. The concurrent requirements for high resolution and broad coverage are normally at odds with one another in commercial instruments, therefore necessitating the development of special instrumentation. The design of a polychromator is reviewed herein, with a detailed discussion of the continuous coverage spectrometer delayed to a later forum. The program also requires the development of applications software providing detection, variable background discrimination, noise reduction, filtering, and decision making based on varying historical data.

  7. Jet engine noise and infrared plume correlation field campaign

    Science.gov (United States)

    Cunio, Phillip M.; Weber, Reed A.; Knobel, Kimberly R.; Smith, Christine; Draudt, Andy

    2015-09-01

    Jet engine noise can be a health hazard and environmental pollutant, particularly affecting personnel working in close proximity to jet engines, such as airline mechanics. Mitigating noise could reduce the potential for hearing loss in runway workers; however, there exists a very complex relationship between jet engine design parameters, operating conditions, and resultant noise power levels, and understanding and characterizing this relationship is a key step in mitigating jet engine noise effects. We demonstrate initial results highlighting the utility of high-speed imaging (hypertemporal imaging) in correlating the infrared signatures of jet engines with acoustic noise. This paper builds on prior theoretical analysis of jet engine infrared signatures and their potential relationships to jet engine acoustic emissions. This previous work identified the region of the jet plume most likely to emit both in infrared and in acoustic domains, and it prompted the investigation of wave packets as a physical construct tying together acoustic and infrared energy emissions. As a means of verifying these assertions, a field campaign to collect relevant data was proposed, and data collection was carried out with a bank of infrared instruments imaging a T700 turboshaft engine undergoing routine operational testing. The detection of hypertemporal signatures in association with acoustic signatures of jet engines enables the use of a new domain in characterizing jet engine noise. This may in turn enable new methods of predicting or mitigating jet engine noise, which could lead to socioeconomic benefits for airlines and other operators of large numbers of jet engines.

  8. Laser pointing in the vicinity of jet engine plumes

    Science.gov (United States)

    Schleijpen, Ric H. M. A.

    2009-09-01

    Target tracking and laser-based pointing from airborne platforms can be degraded significantly by the propagation environment around an airborne platform including zones of severe turbulence generated by rotor downwash and engine exhausts. This is the topic of the EDA study group ERG 108.019 on "Laser beam propagation and imaging through severe environments". This paper reports on experiments on optical propagation in the vicinity of a plume of a scaled down jet engine, performed by this co-operation group. The group is also working on methods for estimating the extent of the turbulence effects on the tracking and pointing performance under these conditions.

  9. Status report on a real time Engine Diagnostics Console for rocket engine exhaust plume monitoring

    Science.gov (United States)

    Bircher, F. E.; Gardner, D. G.; Vandyke, D. B.; Harris, A. B.; Chenevert, D. J.

    1990-01-01

    This paper describes the work done on the Engine Diagnostics Console during the past year of development at Stennis Space Center. The Engine Diagnostics Console (EDC) is a hardware and software package which provides near real time monitoring of rocket engine exhaust plume emissions during ground testing. The long range goal of the EDC development program is to develop an instrument that can detect engine degradation leading to catastrophic failure, and respond by taking preventative measures. The immediate goal for the past year's effort is the ability to process spectral data, taken from a rocket engine's exhaust plume, and to identify in an automated and high speed manner, the elemental species and multielemental materials that are present in the exhaust plume.

  10. Stennis Space Center's approach to liquid rocket engine health monitoring using exhaust plume diagnostics

    Science.gov (United States)

    Gardner, D. G.; Tejwani, G. D.; Bircher, F. E.; Loboda, J. A.; Van Dyke, D. B.; Chenevert, D. J.

    1991-01-01

    Details are presented of the approach used in a comprehensive program to utilize exhaust plume diagnostics for rocket engine health-and-condition monitoring and assessing SSME component wear and degradation. This approach incorporates both spectral and video monitoring of the exhaust plume. Video monitoring provides qualitative data for certain types of component wear while spectral monitoring allows both quantitative and qualitative information. Consideration is given to spectral identification of SSME materials and baseline plume emissions.

  11. Theoretical performance of liquid ammonia, hydrazine and mixture of liquid ammonia and hydrazine as fuels with liquid oxygen biflouride as oxidant for rocket engines : I-mixture of liquid ammonia and hydrazine

    Science.gov (United States)

    Huff, Vearl N; Gordon, Sanford

    1952-01-01

    Theoretical performance for mixture of 36.3 percent liquid ammonia and 63.7 percent hydrazine with liquid oxygen bifluoride as rocket propellant was calculated on assumption of equilibrium composition during expansion for a wide range of fuel-oxidant and expansios ratios. Parameters included were specific impulse, combustion-chamber temperature, nozzle exit temperature, composition mean molecular weight, characteristic velocity, coefficient of thrust and ratio of nozzle-exit area to throat area. For chamber pressure of 300 pounds per square inch absolute and expansion to 1 atmosphere, maximum specific impulse was 295.8 pound-seconds per pound. Five percent by weight of water in the hydrazine lowered specific impulse from about one to three units over a wide range of weight-percent fuel.

  12. Thermal Analysis on Plume Heating of the Main Engine on the Crew Exploration Vehicle Service Module

    Science.gov (United States)

    Wang, Xiao-Yen J.; Yuko, James R.

    2007-01-01

    The crew exploration vehicle (CEV) service module (SM) main engine plume heating is analyzed using multiple numerical tools. The chemical equilibrium compositions and applications (CEA) code is used to compute the flow field inside the engine nozzle. The plume expansion into ambient atmosphere is simulated using an axisymmetric space-time conservation element and solution element (CE/SE) Euler code, a computational fluid dynamics (CFD) software. The thermal analysis including both convection and radiation heat transfers from the hot gas inside the engine nozzle and gas radiation from the plume is performed using Thermal Desktop. Three SM configurations, Lockheed Martin (LM) designed 604, 605, and 606 configurations, are considered. Design of multilayer insulation (MLI) for the stowed solar arrays, which is subject to plume heating from the main engine, among the passive thermal control system (PTCS), are proposed and validated.

  13. Space Shuttle main engine OPAD: The search for a hardware enhanced plume

    Science.gov (United States)

    Powers, W. T.; Cooper, A. E.; Wallace, Tim L.; Buntine, W. L.; Whitaker, K. W.

    1993-01-01

    The process of applying spectroscopy to the Space Shuttle Main Engine (SSME) for plume diagnostics, as it exists today, originated at Marshall Space Flight Center in Huntsville, Alabama, and its implementation was assured largely through the efforts of Sverdrup AEDC, in Tullahoma, Tennessee. This team continues to lead and guide efforts in the plume diagnostics arena. The process, Optical Plume Anomaly Detection (OPAD), formed the basis for various activities in the development of ground-based systems as well as the development of in-flight plume spectroscopy. OPAD currently provides and will continue to provide valuable information relative to future systems definitions, instrumentation development, code validation, and data diagnostic processing. OPAD is based on the detection of anomalous atomic and molecular species in the SSME plume using two complete, stand-alone optical spectrometers. To-date OPAD has acquired data on 44 test firings of the SSME at the Technology Test Bed (TTB) at MSFC. The purpose of this paper will be to provide an introduction to the OPAD system by discussing the process of obtaining data as well as the methods of examining and interpreting the data. It will encompass such issues as selection of instrumentation correlation of data to nominal engine operation, investigation of SSME component erosion via OPAD spectral data, necessity and benefits of plume seeding, application of artificial intelligence (AI) techniques to data analysis, and the present status of efforts to quantify specie erosion utilizing standard plume and chemistry codes as well as radiative models currently under development.

  14. On-board Optical Spectrometry for Detection of Mixture Ratio and Eroded Materials in Rocket Engine Exhaust Plume

    Science.gov (United States)

    Barkhoudarian, Sarkis; Kittinger, Scott

    2006-01-01

    Optical spectrometry can provide means to characterize rocket engine exhaust plume impurities due to eroded materials, as well as combustion mixture ratio without any interference with plume. Fiberoptic probes and cables were designed, fabricated and installed on Space Shuttle Main Engines (SSME), allowing monitoring of the plume spectra in real time with a Commercial of the Shelf (COTS) fiberoptic spectrometer, located in a test-stand control room. The probes and the cables survived the harsh engine environments for numerous hot-fire tests. When the plume was seeded with a nickel alloy powder, the spectrometer was able to successfully detect all the metallic and OH radical spectra from 300 to 800 nanometers.

  15. A plume capture technique for the remote characterization of aircraft engine emissions.

    Science.gov (United States)

    Johnson, G R; Mazaheri, M; Ristovski, Z D; Morawska, L

    2008-07-01

    A technique for capturing and analyzing plumes from unmodified aircraft or other combustion sources under real world conditions is described and applied to the task of characterizing plumes from commercial aircraft during the taxiing phase of the Landing/Take-Off (LTO) cycle. The method utilizes a Plume Capture and Analysis System (PCAS) mounted in a four-wheel drive vehicle which is positioned in the airfield 60 to 180 m downwind of aircraft operations. The approach offers low test turnaround times with the ability to complete careful measurements of particle and gaseous emission factors and sequentially scanned particle size distributions without distortion due to plume concentration fluctuations. These measurements can be performed for individual aircraft movements at five minute intervals. A Plume Capture Device (PCD) collected samples of the naturally diluted plume in a 200 L conductive membrane conforming to a defined shape. Samples from over 60 aircraft movements were collected and analyzed in situ for particulate and gaseous concentrations and for particle size distribution using a Scanning Particle Mobility Sizer (SMPS). Emission factors are derived for particle number, NO(x), and PM2.5 for a widely used commercial aircraft type, Boeing 737 airframes with predominantly CFM56 class engines, during taxiing. The practical advantages of the PCAS include the capacity to perform well targeted and controlled emission factor and size distribution measurements using instrumentation with varying response times within an airport facility, in close proximity to aircraft during their normal operations.

  16. Modeling Macro- and Micro-Scale Turbulent Mixing and Chemistry in Engine Exhaust Plumes

    Science.gov (United States)

    Menon, Suresh

    1998-01-01

    Simulation of turbulent mixing and chemical processes in the near-field plume and plume-vortex regimes has been successfully carried out recently using a reduced gas phase kinetics mechanism which substantially decreased the computational cost. A detailed mechanism including gas phase HOx, NOx, and SOx chemistry between the aircraft exhaust and the ambient air in near-field aircraft plumes is compiled. A reduced mechanism capturing the major chemical pathways is developed. Predictions by the reduced mechanism are found to be in good agreement with those by the detailed mechanism. With the reduced chemistry, the computer CPU time is saved by a factor of more than 3.5 for the near-field plume modeling. Distributions of major chemical species are obtained and analyzed. The computed sensitivities of major species with respect to reaction step are deduced for identification of the dominant gas phase kinetic reaction pathways in the jet plume. Both the near field plume and the plume-vortex regimes were investigated using advanced mixing models. In the near field, a stand-alone mixing model was used to investigate the impact of turbulent mixing on the micro- and macro-scale mixing processes using a reduced reaction kinetics model. The plume-vortex regime was simulated using a large-eddy simulation model. Vortex plume behind Boeing 737 and 747 aircraft was simulated along with relevant kinetics. Many features of the computed flow field show reasonable agreement with data. The entrainment of the engine plumes into the wing tip vortices and also the partial detrainment of the plume were numerically captured. The impact of fluid mechanics on the chemical processes was also studied. Results show that there are significant differences between spatial and temporal simulations especially in the predicted SO3 concentrations. This has important implications for the prediction of sulfuric acid aerosols in the wake and may partly explain the discrepancy between past numerical studies

  17. Chemistry in plumes of high-flying aircraft with H2 combustion engines: a modelling study

    Directory of Open Access Journals (Sweden)

    G. Weibring

    Full Text Available Recent discussions on high-speed civil transport (HSCT systems have renewed the interest in the chemistry of supersonic-aircraft plumes. The engines of these aircraft emit large concentrations of radicals like O, H, OH, and NO. In order to study the effect of these species on the composition of the atmosphere, the detailed chemistry of an expanding and cooling plume is examined for different expansion models.

    For a representative flight at 26 km the computed trace gas concentrations do not differ significantly for different models of the expansion behaviour. However, it is shown that the distributions predicted by all these models differ significantly from those adopted in conventional meso-scale and global models in which the plume chemistry is not treated in detail. This applies in particular to the reservoir species HONO and H2O2.

  18. Laser pointing in the vicinity of jet engine plumes

    NARCIS (Netherlands)

    Schleijpen, H.M.A.

    2009-01-01

    Target tracking and laser-based pointing from airborne platforms can be degraded significantly by the propagation environment around an airborne platform including zones of severe turbulence generated by rotor downwash and engine exhausts. This is the topic of the EDA study group ERG 108.019 on "Las

  19. Laser pointing in the vicinity of jet engine plumes

    NARCIS (Netherlands)

    Schleijpen, H.M.A.

    2010-01-01

    Target tracking and laser-based pointing from airborne platforms can be degraded significantly by the propagation environment around an airborne platform including zones of severe turbulence generated by rotor downwash and engine exhausts. This is the topic of the EDA study group ERG 108.019 on “Las

  20. Mars to orbit with pumped hydrazine

    Energy Technology Data Exchange (ETDEWEB)

    Whitehead, J C

    1999-04-27

    A propulsion point design is presented for lifting geological samples from Mars. Vehicle complexity is kept low by choosing a monopropellant single stage. Little new development is needed, as miniature pump fed hydrazine has been demonstrated. Loading the propellant just prior to operation avoids structural, thermal, and safety constraints otherwise imposed by earlier mission phases. Hardware mass and engineering effort are thereby diminished. The Mars liftoff mass is 7/8 hydrazine, <5% propulsion hardware, and >3% each for the payload and guidance.

  1. Rocket-Plume Spectroscopy Simulation for Hydrocarbon-Fueled Rocket Engines

    Science.gov (United States)

    Tejwani, Gopal D.

    2010-01-01

    The UV-Vis spectroscopic system for plume diagnostics monitors rocket engine health by using several analytical tools developed at Stennis Space Center (SSC), including the rocket plume spectroscopy simulation code (RPSSC), to identify and quantify the alloys from the metallic elements observed in engine plumes. Because the hydrocarbon-fueled rocket engine is likely to contain C2, CO, CH, CN, and NO in addition to OH and H2O, the relevant electronic bands of these molecules in the spectral range of 300 to 850 nm in the RPSSC have been included. SSC incorporated several enhancements and modifications to the original line-by-line spectral simulation computer program implemented for plume spectral data analysis and quantification in 1994. These changes made the program applicable to the Space Shuttle Main Engine (SSME) and the Diagnostic Testbed Facility Thruster (DTFT) exhaust plume spectral data. Modifications included updating the molecular and spectral parameters for OH, adding spectral parameter input files optimized for the 10 elements of interest in the spectral range from 320 to 430 nm and linking the output to graphing and analysis packages. Additionally, the ability to handle the non-uniform wavelength interval at which the spectral computations are made was added. This allowed a precise superposition of wavelengths at which the spectral measurements have been made with the wavelengths at which the spectral computations are done by using the line-by-line (LBL) code. To account for hydrocarbon combustion products in the plume, which might interfere with detection and quantification of metallic elements in the spectral region of 300 to 850 nm, the spectroscopic code has been enhanced to include the carbon-based combustion species of C2, CO, and CH. In addition, CN and NO have spectral bands in 300 to 850 nm and, while these molecules are not direct products of hydrocarbon-oxygen combustion systems, they can show up if nitrogen or a nitrogen compound is present

  2. The catalysis of hydrazines

    Science.gov (United States)

    Tanatar, S.

    1987-01-01

    Hydrazine sulfate in a hot aqueous solution can be catalyzed in the direction of 3 N2H4 = 4 NH3 + N2. Free hydrazine in a hot aqueous solution dissociates in the presence of platinum in the following direction: 2 N2H4 = 2 NH3 + N2 + H2. In the presence of sodium hydroxide, the catalytic dissociation of hydrazine takes a third direction: 3 N2H4 = 2 NH3 + 2 N3 + 3 H2.

  3. X-33 XRS-2200 Linear Aerospike Engine Sea Level Plume Radiation

    Science.gov (United States)

    DAgostino, Mark G.; Lee, Young C.; Wang, Ten-See; Turner, Jim (Technical Monitor)

    2001-01-01

    Wide band plume radiation data were collected during ten sea level tests of a single XRS-2200 engine at the NASA Stennis Space Center in 1999 and 2000. The XRS-2200 is a liquid hydrogen/liquid oxygen fueled, gas generator cycle linear aerospike engine which develops 204,420 lbf thrust at sea level. Instrumentation consisted of six hemispherical radiometers and one narrow view radiometer. Test conditions varied from 100% to 57% power level (PL) and 6.0 to 4.5 oxidizer to fuel (O/F) ratio. Measured radiation rates generally increased with engine chamber pressure and mixture ratio. One hundred percent power level radiation data were compared to predictions made with the FDNS and GASRAD codes. Predicted levels ranged from 42% over to 7% under average test values.

  4. Thermal radiation of heterogeneous combustion products in the model rocket engine plume

    Science.gov (United States)

    Kuzmin, V. A.; Maratkanova, E. I.; Zagray, I. A.; Rukavishnikova, R. V.

    2015-05-01

    The work presents a method of complex investigation of thermal radiation emitted by heterogeneous combustion products in the model rocket engine plume. Realization of the method has allowed us to obtain full information on the results in all stages of calculations. Dependence of the optical properties (complex refractive index), the radiation characteristics (coefficients and cross sections) and emission characteristics (flux densities, emissivity factors) of the main determining factors and parameters was analyzed. It was found by the method of computational experiment that the presence of the gaseous phase in the combustion products causes a strongly marked selectivity of emission, due to which the use of gray approximation in the calculation of thermal radiation is unnecessary. The influence of the optical properties, mass fraction, the function of particle size distribution, and the temperature of combustion products on thermal radiation in the model rocket engine plume was investigated. The role of "spotlight" effect-increasing the amount of energy of emission exhaust combustion products due to scattering by condensate particles radiation from the combustion chamber-was established quantitatively.

  5. Acoustic interactions between an altitude test facility and jet engine plumes: Theory and experiments

    Science.gov (United States)

    Ahuja, K. K.; Jones, R. R., III; Tam, C. K.; Massey, K. C.; Fleming, A. J.

    1992-01-01

    The overall objective of the described effort was to develop an understanding of the physical mechanisms involved in the flow/acoustic interactions experienced in full-scale altitude engine test facilities. This is done by conducting subscale experiments and through development of a theoretical model. Model cold jet experiments with an axisymmetric convergent nozzle are performed in a test setup that stimulates a supersonic jet exhausting into a cylindrical diffuser. The measured data consist of detailed flow visualization data and acoustic spectra for a free and a ducted plume. It is shown that duct resonance is most likely responsible by theoretical calculations. Theoretical calculations also indicate that the higher discrete tones observed in the measurements are related to the screech phenomena. Limited experiments on the sensitivity of a free 2-D, C-D nozzle to externally imposed sound are also presented. It is shown that a 2-D, C-D nozzle with a cutback is less excitable than a 2-D C-D nozzle with no cutback. At a pressure ratio of 1.5 unsteady separation from the diverging walls of the nozzle is noticed. This separation switches from one wall to the opposite wall thus providing an unsteady deflection of the plume. It is shown that this phenomenon is related to the venting provided by the cutback section.

  6. Real Time Diagnostics of Jet Engine Exhaust Plumes Using a Chirped QC Laser Spectrometer

    Science.gov (United States)

    Hay, K. G.; Duxbury, G.; Langford, N.

    2010-06-01

    Quantitative measurements of real-time variations of the chemical composition of a jet engine exhaust plume is demonstrated using a 4.86 μmn intra-pulse quantum cascade laser spectrometer. The measurements of the gas turbine exhaust were carried out in collaboration with John Black and Mark Johnson at Rolls Royce. The recording of five sets of averaged spectra a second has allowed us to follow the build up of the combustion products within the exhaust, and to demonstrate the large variation of the integrated absorption of these absorption lines with temperature. The absorption cross sections of the lines of both carbon monoxide and water increase with temperature, whereas those of the three main absorption lines of carbon dioxide decrease. At the steady state limit the absorption lines of carbon dioxide are barely visible, and the spectrum is dominated by absorption lines of carbon monoxide and water.

  7. Analysis of reacting flowfields in low-thrust rocket engines and plumes

    Science.gov (United States)

    Weiss, Jonathan Mitchell

    The mixing and combustion processes in small gaseous hydrogen-oxygen thrusters and plumes are studied by means of a computational model developed as a general purpose analytic procedure for solving low speed, reacting, internal flowfields. The model includes the full Navier-Stokes equations coupled with species diffusion equations for a hydrogen-oxygen reaction kinetics system as well as the option to use either the k-Epsilon or q-Omega low Reynolds number, two-equation turbulence models. Solution of the governing equations is accomplished by a finite-volume formulation with central-difference spatial discretizations and an explicit, four-stage, Runge Kutta time-integration procedure. The Runge-Kutta scheme appears to provide efficient convergence when applied to the calculation of turbulent, reacting flowfields in these small thrusters. Appropriate boundary conditions are developed to properly model propellant mass flowrates and regenerative wall cooling. The computational method is validated against measured engine performance parameters on a global level, as well as experimentally obtained exit plane and plume flowfield properties on a local level. The model does an excellent job of predicting the measured performance trends of an auxiliary thruster as a function of O/F ratio, although the performance levels are consistently underpredicted by approximately 4 percent. These differences arise because the extent to which the wall coolant layer and combustion gases mix and react is underpredicted. Predictions of velocity components, temperature and species number densities in the near-field plume regions of several low-thrust engines show reasonable agreement with experimental data obtained by two separate laser diagnostic techniques. Discrepancies between the predictions and measurements are primarily due to three-dimensional mixing processes which are not accounted for in the analysis. Both comparisons with experiment and the evident reason for errors in absolute

  8. Hydrazine inactivates bacillus spores

    Science.gov (United States)

    Schubert, Wayne; Plett, G. A.; Yavrouian, A. H.; Barengoltz, J.

    2005-01-01

    Planetary Protection places requirements on the maximum number of viable bacterial spores that may be delivered by a spacecraft to another solar system body. Therefore, for such space missions, the spores that may be found in hydrazine are of concern. A proposed change in processing procedures that eliminated a 0.2 um filtration step propmpted this study to ensure microbial contamination issue existed, especially since no information was found in the literature to substantiate bacterial spore inactivation by hydrazine.

  9. Calculation of Free-Atom Fractions in Hydrocarbon-Fueled Rocket Engine Plume

    Science.gov (United States)

    Verma, Satyajit

    2006-01-01

    Free atom fractions (Beta) of nine elements are calculated in the exhaust plume of CH4- oxygen and RP-1-oxygen fueled rocket engines using free energy minimization method. The Chemical Equilibrium and Applications (CEA) computer program developed by the Glenn Research Center, NASA is used for this purpose. Data on variation of Beta in both fuels as a function of temperature (1600 K - 3100 K) and oxygen to fuel ratios (1.75 to 2.25 by weight) is presented in both tabular and graphical forms. Recommendation is made for the Beta value for a tenth element, Palladium. The CEA computer code was also run to compare with experimentally determined Beta values reported in literature for some of these elements. A reasonable agreement, within a factor of three, between the calculated and reported values is observed. Values reported in this work will be used as a first approximation for pilot rocket engine testing studies at the Stennis Space Center for at least six elements Al, Ca, Cr, Cu, Fe and Ni - until experimental values are generated. The current estimates will be improved when more complete thermodynamic data on the remaining four elements Ag, Co, Mn and Pd are added to the database. A critique of the CEA code is also included.

  10. Near-field commercial aircraft contribution to nitrogen oxides by engine, aircraft type, and airline by individual plume sampling.

    Science.gov (United States)

    Carslaw, David C; Ropkins, Karl; Laxen, Duncan; Moorcroft, Stephen; Marner, Ben; Williams, Martin L

    2008-03-15

    Nitrogen oxides (NOx) concentrations were measured in individual plumes from aircraft departing on the northern runway at Heathrow Airport in west London. Over a period of four weeks 5618 individual plumes were sampled by a chemiluminescence monitor located 180 m from the runway. Results were processed and matched with detailed aircraft movement and aircraft engine data using chromatographic techniques. Peak concentrations associated with 29 commonly used engines were calculated and found to have a good relationship with N0x emissions taken from the International Civil Aviation Organization (ICAO) databank. However, it is found that engines with higher reported NOx emissions result in proportionately lower NOx concentrations than engines with lower emissions. We show that it is likely that aircraft operational factors such as takeoff weight and aircraftthrust setting have a measurable and important effect on concentrations of N0x. For example, NOx concentrations can differ by up to 41% for aircraft using the same airframe and engine type, while those due to the same engine type in different airframes can differ by 28%. These differences are as great as, if not greater than, the reported differences in NOx emissions between different engine manufacturers for engines used on the same airframe.

  11. COMPLEXES CONTAINING HYDRAZINE AND BENZYL ...

    African Journals Online (AJOL)

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    In previous reports, anhydrous hydrazine and substituted hydrazine were ... DRX 250 spectrometer while that of 3 was recorded on a Bruker 300 MHz instrument at ... The hydrazine complex was prepared from the polymer [{RuCl2(COD)}x] by the ... solution and the acetone was removed under reduced pressure and a white ...

  12. Prediction of engine and near-field plume reacting flows in low-thrust chemical rockets

    Science.gov (United States)

    Weiss, Jonathan M.; Merkle, Charles L.

    1993-01-01

    A computational model is employed to study the reacting flow within the engine and near-field plumes of several small gaseous hydrogen-oxygen thrusters. The model solves the full Navier-Stokes equations coupled with species diffusion equations for a hydrogen-oxygen reaction kinetics system and includes a two-equation q-omega model for turbulence. Predictions of global performance parameters and localized flowfield variables are compared with experimental data in order to assess the accuracy with which these flowfields are modeled and to identify aspects of the model which require improvement. Predicted axial and radial velocities 3 mm downstream of the exit plane show reasonable agreement with the measurements. The predicted peak in axial velocity in the hydrogen film coolant along the nozzle wall shows the best agreement; however, predictions within the core region are roughly 15 percent below measured values, indicating an underprediction of the extent to which the hydrogen diffuses and mixes with the core flow. There is evidence that this is due to three-dimensional mixing processes which are not included in the axisymmetric model.

  13. MODELLING AND MEASUREMENT OF NOx CONCENTRATION IN PLUME FROM AIRCRAFT ENGINE UNDER OPERATION CONDITIONS AT THE AERODROME AREA

    Directory of Open Access Journals (Sweden)

    Oleksandr Zaporozhets

    2016-06-01

    Full Text Available Purpose: Airport air pollution is growing concern because of the air traffic expansion over the years (at annual rate of 5 %, rising tension of airports and growing cities expansion close each other (for such Ukrainian airports, as Zhulyany, Boryspol, Lviv, Odesa and Zaporizhzhia and accordingly growing public concern with air quality around the airport. Analysis of inventory emission results at major European and Ukrainian airports highlighted, that an aircraft is the dominant source of air pollution in most cases under consideration. For accurate assessment of aircraft emission contribution to total airport pollution and development of successful mitigation strategies, it is necessary to combine the modeling and measurement methods. Methods: Measurement of NOx concentration in the jet/plume from aircraft engine was implemented by chemiluminescence method under real operating conditions (taxi, landing, accelerating on the runway and take-off at International Boryspol airport (IBA. Modeling of NOx concentration was done by complex model PolEmiCa, which takes into account the transport and dilution of air contaminates by exhaust gases jet and the wing trailing vortexes.Results: The results of the measured NOx concentration in plume from aircraft engine for take-off conditions at IBA were used for improvement and validation of the complex model PolEmiCa. The comparison of measured and modeled instantaneous concentration of NOx was sufficiently improved by taking into account the impact of wing trailing vortices on the parameters of the jet (buoyancy height, horizontal and vertical deviation and on concentration distribution in plume. Discussion: Combined approach of modeling and measurement methods provides more accurate representation of aircraft emission contribution to total air pollution in airport area. Modeling side provides scientific grounding for organization of instrumental monitoring of aircraft engine emissions, particularly, scheme

  14. Great Market Potential of Hydrazine Hydrate

    Institute of Scientific and Technical Information of China (English)

    Shi Yuying

    2007-01-01

    @@ Stable consumption growth worldwide Hydrazine hydrate is an organic chemical raw material with extensive applications. The world's capacity to produce hydrazine hydrate has reached more than 200 thousand t/atoday (based on 100% hydrazine content).

  15. Toxicity assessment of hydrazine fuels

    Energy Technology Data Exchange (ETDEWEB)

    Keller, W.C.

    1988-11-01

    The major health aspects of exposure to hydrazine propellants are reviewed. Toxic effects of hydrazine fuels on humans and animals as well as in vitro studies are discussed with emphasis on recent findings and USAF studies. Propellant hydrazines have been found to be genotoxic in in vitro studies and oncogenic in animal studies. Embryotoxicity has been demonstrated at very high exposures but not at occupationally encountered levels for hydrazine and unsymmetrical dimethylhydrazine. Epidemiologic evidence to support these findings is lacking; however, the results of animal and in vitro studies have resulted in lowering both the time-weighted average-threshold limit values and short-term exposure limits for these propellants.

  16. Spacecraft plume interactions with the magnetosphere plasma environment in geostationary Earth orbit

    Science.gov (United States)

    Stephani, K. A.; Boyd, I. D.

    2016-02-01

    Particle-based kinetic simulations of steady and unsteady hydrazine chemical rocket plumes are presented in a study of plume interactions with the ambient magnetosphere in geostationary Earth orbit. The hydrazine chemical rocket plume expands into a near-vacuum plasma environment, requiring the use of a combined direct simulation Monte Carlo/particle-in-cell methodology for the rarefied plasma conditions. Detailed total and differential cross sections are employed to characterize the charge exchange reactions between the neutral hydrazine plume mixture and the ambient hydrogen ions, and ion production is also modeled for photoionization processes. These ionization processes lead to an increase in local plasma density surrounding the spacecraft owing to a partial ionization of the relatively high-density hydrazine plume. Results from the steady plume simulations indicate that the formation of the hydrazine ion plume are driven by several competing mechanisms, including (1) local depletion and (2) replenishing of ambient H+ ions by charge exchange and thermal motion of 1 keV H+ from the ambient reservoir, respectively, and (3) photoionization processes. The self-consistent electrostatic field forces and the geostationary magnetic field have only a small influence on the dynamics of the ion plume. The unsteady plume simulations show a variation in neutral and ion plume dissipation times consistent with the variation in relative diffusion rates of the chemical species, with full H2 dissipation (below the ambient number density levels) approximately 33 s after a 2 s thruster burn.

  17. Sensitized Liquid Hydrazine Detonation Studies

    Science.gov (United States)

    Rathgeber, K. A.; Keddy, C. P.; Bunker, R. L.

    1999-01-01

    Vapor-phase hydrazine (N2H4) is known to be very sensitive to detonation while liquid hydrazine is very insensitive to detonation, theoretically requiring extremely high pressures to induce initiation. A review of literature on solid and liquid explosives shows that when pure explosive substances are infiltrated with gas cavities, voids, and/or different phase contaminants, the energy or shock pressure necessary to induce detonation can decrease by an order of magnitude. Tests were conducted with liquid hydrazine in a modified card-gap configuration. Sensitization was attempted by bubbling helium gas through and/or suspending ceramic microspheres in the liquid. The hydrazine was subjected to the shock pressure from a 2 lb (0.9 kg) Composition C-4 explosive charge. The hydrazine was contained in a 4 in. (10.2 cm) diameter stainless steel cylinder with a 122 in(sup 3) (2 L) volume and sealed with a polyethylene cap. Blast pressures from the events were recorded by 63 high speed pressure transducers located on three radial legs extending from 4 to 115 ft (1.2 to 35.1 in) from ground zero. Comparison of the neat hydrazine and water baseline tests with the "sensitized" hydrazine tests indicates the liquid hydrazine did not detonate under these conditions.

  18. Environmental Fate of Hydrazines

    Science.gov (United States)

    1989-12-01

    v/v. The absorbent cartridges removed trace gas contaminants , including remaining water and CO2 . Gas outlet-valves after each unit provided for air...largest kbkg was observed in Run A, presumably due to the interaction of hydrazine vapor with contamination on the chamber walls accumulated during its...64 UDMH Dry Air 2.8 19 13 1.1 a Ambirnt temperature, 50-75 ppm v/v initial concentrationb 24 m of added FEP c 14,700 ppm v/v water vapor Of these

  19. Analysis of large solid propellant rocket engine exhaust plumes using the direct simulation Monte Carlo method

    Science.gov (United States)

    Hueser, J. E.; Brock, F. J.; Melfi, L. T., Jr.; Bird, G. A.

    1984-01-01

    A new solution procedure has been developed to analyze the flowfield properties in the vicinity of the Inertial Upper Stage/Spacecraft during the 1st stage (SRMI) burn. Continuum methods are used to compute the nozzle flow and the exhaust plume flowfield as far as the boundary where the breakdown of translational equilibrium leaves these methods invalid. The Direct Simulation Monte Carlo (DSMC) method is applied everywhere beyond this breakdown boundary. The flowfield distributions of density, velocity, temperature, relative abundance, surface flux density, and pressure are discussed for each species for 2 sets of boundary conditions: vacuum and freestream. The interaction of the exhaust plume and the freestream with the spacecraft and the 2-stream direct interaction are discussed. The results show that the low density, high velocity, counter flowing free-stream substantially modifies the flowfield properties and the flux density incident on the spacecraft. A freestream bow shock is observed in the data, located forward of the high density region of the exhaust plume into which the freestream gas does not penetrate. The total flux density incident on the spacecraft, integrated over the SRM1 burn interval is estimated to be of the order of 10 to the 22nd per sq m (about 1000 atomic layers).

  20. Investigating potential correlations between jet engine noise and plume dynamics in the hypertemporal infrared domain

    Science.gov (United States)

    Cunio, Phillip M.; Weber, Reed; Knobel, Kimberly; Wager, Jason; Lopez, Gerardo

    2014-09-01

    Jet engine noise can be a hazard and environmental pollutant, affecting personnel working in close proximity to jet engines. Mitigating the effects of jet engine noise could reduce the potential for hearing loss in runway workers, but engine noise is not yet sufficiently well-characterized that it can easily be mitigated for new engine designs. That is, there exists a very complex relationship between jet engine design parameters, operating conditions, and resultant noise power levels. In this paper, we propose to evaluate the utility of high-speed imaging (also called hypertemporal imaging) in correlating the infrared signatures of jet aircraft engines with acoustic noise from the jet engines. This paper will focus on a theoretical analysis of jet engine infrared signatures, and will define potentially-detectable characteristics of such signatures in the hypertemporal domain. A systematic test campaign to determine whether such signatures actually exist and can be correlated with acoustic jet engine characteristics will be proposed. The detection of any hypertemporal signatures in association with acoustic signatures of jet engines will enable the use of a new domain in characterizing jet engine noise. This may in turn enable new methods of predicting or mitigating jet engine noise, which could lead to benefits for operators of large numbers of jet engines.

  1. A comparison of shuttle vernier engine plume contamination with CONTAM 3.4 code predictions

    Science.gov (United States)

    Maag, Carl R.; Jones, Thomas M.; Rao, Shankar M.; Linder, W. Kelly

    1992-01-01

    In 1985, using the CONTAM 3.2 code, it was predicted that the shuttle Primary Reaction Control System (PRCS) and Vernier Reaction Control System (VRCS) engines could be potential contamination sources to sensitive surfaces located within the shuttle payload bay. Spaceflight test data on these engines is quite limited. Shuttle mission STS-32, the Long Duration Exposure Facility retrieval mission, was instrumented with an experiment that provided the design engineer with evidence that contaminant species from the VRCS engines can enter the payload bay. More recently, the most recent version of the analysis code, CONTAM 3.4, has re-examined the contamination potential of these engines.

  2. Hydrazine vapor inactivates Bacillus spores

    Science.gov (United States)

    Schubert, Wayne W.; Engler, Diane L.; Beaudet, Robert A.

    2016-05-01

    NASA policy restricts the total number of bacterial spores that can remain on a spacecraft traveling to any planetary body which might harbor life or have evidence of past life. Hydrazine, N2H4, is commonly used as a propellant on spacecraft. Hydrazine as a liquid is known to inactivate bacterial spores. We have now verified that hydrazine vapor also inactivates bacterial spores. After Bacillus atrophaeus ATCC 9372 spores deposited on stainless steel coupons were exposed to saturated hydrazine vapor in closed containers, the spores were recovered from the coupons, serially diluted, pour plated and the surviving bacterial colonies were counted. The exposure times required to reduce the spore population by a factor of ten, known as the D-value, were 4.70 ± 0.50 h at 25 °C and 2.85 ± 0.13 h at 35 °C. These inactivation rates are short enough to ensure that the bioburden of the surfaces and volumes would be negligible after prolonged exposure to hydrazine vapor. Thus, all the propellant tubing and internal tank surfaces exposed to hydrazine vapor do not contribute to the total spore count.

  3. Observation of the exhaust plume from the space shuttle main engine using the Microwave Limb Sounder

    Directory of Open Access Journals (Sweden)

    H. C. Pumphrey

    2010-08-01

    Full Text Available A space shuttle launch deposits 700 t of water in the atmosphere. Some of this water is released into the upper mesosphere and lower thermosphere where it may be directly detected by a limb sounding satellite instrument. We report measurements of water vapour plumes from shuttle launches made by the Microwave Limb Sounder (MLS on the Aura satellite. Approximately 50% of shuttle launches are detected by MLS. The signal appears at a similar level across the upper 10 km of the MLS limb scan, suggesting that the bulk of the observed water is above the top of the scan. Only a small fraction at best of smaller launches (Ariane, Proton are detected. We conclude that the sensitivity of MLS is only just great enough to detect a shuttle sized launch, but that a suitably designed instrument of the same general type could detect the exhausts from a large proportion of heavy-lift launches.

  4. Observation of the exhaust plume from the space shuttle main engines using the microwave limb sounder

    Directory of Open Access Journals (Sweden)

    H. C. Pumphrey

    2011-01-01

    Full Text Available A space shuttle launch deposits 700 tonnes of water in the atmosphere. Some of this water is released into the upper mesosphere and lower thermosphere where it may be directly detected by a limb sounding satellite instrument. We report measurements of water vapour plumes from shuttle launches made by the Microwave Limb Sounder (MLS on the Aura satellite. Approximately 50%–65% of shuttle launches are detected by MLS. The signal appears at a similar level across the upper 10 km of the MLS limb scan, suggesting that the bulk of the observed water is above the top of the scan. Only a small fraction at best of smaller launches (Ariane 5, Proton are detected. We conclude that the sensitivity of MLS is only just great enough to detect a shuttle sized launch, but that a suitably designed instrument of the same general type could detect the exhausts from a large proportion of heavy-lift launches.

  5. Hyperspectral Imaging of a Turbine Engine Exhaust Plume to Determine Radiance, Temperature, and Concentration Spatial Distributions

    Science.gov (United States)

    2009-03-01

    MATLAB_DIRECTORY)); Filepath = [’/home/scratch2/sbowen/20081105/’... �-EngineTestKeroseneFuel/offset_corrected/’]; Datapath ...8217... �-EngineTestKeroseneFuel/offset_corrected/’]; Datapath = [Filepath ’Figures’]; cd(Filepath); prefix = ’LowRPM’ %% Optimize

  6. Laser Transmission Measurements of Soot Extinction Coefficients in the Exhaust Plume of the X-34 60k-lb Thrust Fastrac Rocket Engine

    Science.gov (United States)

    Dobson, C. C.; Eskridge, R. H.; Lee, M. H.

    2000-01-01

    A four-channel laser transmissometer has been used to probe the soot content of the exhaust plume of the X-34 60k-lb thrust Fastrac rocket engine at NASA's Marshall Space Flight Center. The transmission measurements were made at an axial location about equal 1.65 nozzle diameters from the exit plane and are interpreted in terms of homogeneous radial zones to yield extinction coefficients from 0.5-8.4 per meter. The corresponding soot mass density, spatially averaged over the plume cross section, is, for Rayleigh particles, approximately equal to 0.7 micrograms/cubic cm and alternative particle distributions are briefly considered. Absolute plume radiance at the laser wavelength (515 nm) is estimated from the data at approximately equal to 2.200 K equivalent blackbody temperature, and temporal correlations in emission from several spatial locations are noted.

  7. Electrochemical Disposal of Hydrazines in Water

    Science.gov (United States)

    Kim, Jinseong; Gonzalez-Mar, Anuncia; Salinas, Carlos; Rutherford, Larris; Jeng, King-Tsai; Andrews, Craig; Yalamanchili, Ratlaya

    2007-01-01

    An electrochemical method of disposal of hydrazines dissolved in water has been devised. The method is applicable to hydrazine (N2H4), to monomethyl hydrazine [also denoted by MMH or by its chemical formula, (CH3)HNNH2], and to unsymmetrical dimethyl hydrazine [also denoted UDMH or by its chemical formula, (CH3)2NNH2]. The method involves a room-temperature process that converts the hydrazine to the harmless products N2, H2O, and, in some cases, CO2

  8. Occupational safety considerations with hydrazine

    Science.gov (United States)

    Clewell, Harvey J., III; Mcdougal, James N.; George, Marilyn E.; Andersen, Melvin E.

    1992-01-01

    Hydrazine is a reducing agent that is most commonly used as a propellant and as an oxygen scavenger in boilers. Hydrazine is extremely irritating and has been demonstrated to produce both acute and chronic toxicity. As a result, the established permissible inhalation exposure limits are very low, and respiration protection is required whenever vapors are present. Liquid hydrazine penetrates the skin and produces a chemical burn; therefore, some protective measures must also be taken to protect the skin from liquid contact. Often, however, a cumbersome, whole-body protective suit is worn to protect against skin contact with vapor as well. To what extent it is actually necessary to protect skin from vapor penetration had not previously been demonstrated. In an attempt to answer this question, we conducted a study with rats to compare the dermal penetration of hydrazine vapor with inhalation. Pharmacokinetic modeling was used to compare body burdens resulting from these different routes of exposure. The analysis concluded that the vapor concentration during a skin-only exposure would have to be at least 200 times higher than that during inhalation to achieve the same body burden. This type of estimation illustrates the use of predictive toxicology in occupational exposures.

  9. Plume Interaction and Base Flow Analysis of a Twin Engine Flight Vehicle

    Science.gov (United States)

    Chandra Murty, Mamidi Sri Rama; Chakraborty, Debasis

    2016-06-01

    3D RANS simulations are performed to study the multi jet interactions of a twin engine gimbal configuration of an aerospace vehicle at different time instants. Simulations captured all the essential features of the flow field and interaction between the neighboring jets did not occur because of low altitudes and moderate under-expansion of the jets considered in the simulations. For higher gimbal angle, two jets were the closest but still did not interact. Detail exploration of the downstream flow field revealed that the distinct features of the jets are retained at the farthest downstream locations; although the pressure field reached the uniformity. Average base pressure ratios for the three different time instances are 0.91, 0.547 and 0.522 and maximum base temperature is of the order 800 K.

  10. Observations of primary and secondary emissions in a B747 exhaust plume in the upper troposphere and inferred engine exit plane OH concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Schlager, H.; Schulte, P.; Tremmel, H.G.; Ziereis, H. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere; Arnold, F.; Droste-Franke, B.; Klemm, M.; Schneider, J. [Max-Planck-Inst. fuer Kernphysik, Heidelberg (Germany)

    1997-12-31

    The speciation of NO{sub y} exhaust emissions in the near-field plume of a B747 cruising at 9.2 km was measured in situ using the DLR Falcon research aircraft instrumented with a chemical ionisation mass spectrometer of MPI-K and a chemiluminescence NO detector of DLR. In addition, CO{sub 2} was measured providing a dilution factor for the exhaust species. Observed maximum peak concentrations above background in the plume 60 s after emission were 25.4 ppmv (CO{sub 2}), 184 ppbv (NO), 2.6 ppbv (HNO{sub 2}), and 1.3 ppbv (HNO{sub 3}). The observations were used to infer the initial OH concentration (15.4 ppmv) and NO{sub 2}/NO{sub x} ratio (0.08) at the engine exit by back calculations using a chemistry box model. (author) 20 refs.

  11. Active Hydrazine Vapor Sampler (AHVS)

    Science.gov (United States)

    Young, Rebecca C.; Mcbrearty, Charles F.; Curran, Daniel J.

    1993-01-01

    The Active Hydrazine Vapor Sampler (AHVS) was developed to detect vapors of hydrazine (HZ) and monomethylhydrazine (MMH) in air at parts-per-billion (ppb) concentration levels. The sampler consists of a commercial personal pump that draws ambient air through paper tape treated with vanillin (4-hydroxy-3-methoxybenzaldehyde). The paper tape is sandwiched in a thin cardboard housing inserted in one of the two specially designed holders to facilitate sampling. Contaminated air reacts with vanillin to develop a yellow color. The density of the color is proportional to the concentration of HZ or MMH. The AHVS can detect 10 ppb in less than 5 minutes. The sampler is easy to use, low cost, and intrinsically safe and contains no toxic material. It is most beneficial for use in locations with no laboratory capabilities for instrumentation calibration. This paper reviews the development, laboratory test, and field test of the device.

  12. The Oxidation of Hydrazine by Nitric Acid

    Energy Technology Data Exchange (ETDEWEB)

    Karraker, D.G.

    2001-07-02

    Hydrazine nitrate-nitric acid solutions are used in the ion exchange process for separating Pu-238 and Np-237 and have been found to dissolve plutonium metal in a manner advantageous to SRP metal recovery operations. Laboratory tests on the stability of hydrazine in nitric acid solutions were performed to obtain accurate data, and the results of these tests are reported here. These tests provide sufficient information to specify temperature control for hydrazine-nitric acid solutions in plant processes.

  13. Analysis of nonequilibrium chemical processes in the plume of subsonic and supersonic aircraft with hydrogen and hydrocarbon combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Starik, A.M.; Lebedev, A.B.; Titova, N.S. [Central Inst. of Aviation Motors, Moscow (Russian Federation)

    1997-12-31

    On the basic of quasi one dimensional mixing model the numerical analysis of nonequilibrium chemical processes in the plume of subsonic and hypersonic aircraft is presented. It was found that species HNO, HNO{sub 3}, HNO{sub 4}, N{sub 2}O{sub 5}, ClO{sub 2}, CH{sub 3}NO{sub 2} could be formed as a result of nonequilibrium processes in the plume and their concentrations can essentially exceed both background values in free stream of atmosphere and their values at the nozzle exit plane. (author) 10 refs.

  14. Occupational safety considerations with hydrazine fuels

    Science.gov (United States)

    Clewell, H. J.; Haddad, T. S.; George, M. E.; Mcdougal, J. N.; Andersen, M. E.

    1992-01-01

    A simple pharmacokinetic model and a specially designed dermal vapor exposure chamber which provides respiratory protection were used to determine the rate of penetration of hydrazine and 1,1-dimethylhydrazine (UDMH) vapor through the skin of rats. Parameters for the pharmacokinetic model were determined from intravenous and inhalation exposure data. The model was then used to estimate the skin permeation coefficient for hydrazine or UDMH vapor from the dermal-vapor exposure data. This analysis indicates that UDMH vapor has a relatively high permeability through skin (0.7 cm/hr), a value somewhat higher than was obtained for hydrazine by the same procedure (0.09 cm/hr). Based on these skin permeability results, a skin-only vapor exposure limit giving protection equivalent to the inhalation Threshold Limit Value (TLV) could be calculated. The current TLV's for UDMH and hydrazine are 0.5 and 0.1 ppm, respectively. The corresponding skin-only TLV equivalents, for personnel wearing respiratory protection, are 32 ppm for UDMH and 48 ppm for hydrazine. Should the proposed lowering to the TLV's for these compounds to 0.01 ppm be adopted, the equivalent skin-only TLV's would become 0.64 ppm for UDMH and 4.8 for hydrazine.

  15. Destruction of Hydrazine and Corrosion Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Won, H. J.; Park, S. Y.; Kim, S. B.; Jung, J. Y.; Choi, W. K.; Moon, J. K. [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    KAERI The agent uses Cu ion and hydrazine in an inorganic acid solution. This agent is used for the dissolution of Fe and Ni ions in a spinel type nickel chromium ferrite. After decontamination, the generation of the secondary waste can be reduced by the destruction of hydrazine. Wellman et al. reported that hydrazine is decomposed to water and nitrogen by hydrogen peroxide in the presence of Cu{sup 2+} ion. N{sub 2}H{sub 4}+2H{sub 2}0{sub 2} (Cu{sup 2+} →) N{sub 2} +4H{sub 2}0 As the decrease of the hydrazine concentration, the solution pH also becomes to decrease. The decrease of solution pH can affect the integrity of structural metal. The objective of the study is to investigate the decomposition characteristics of hydrazine by hydrogen peroxide. The corrosion compatibility of metal after the decomposition of hydrazine is also investigated. The application of a decontamination solution to the primary coolant system before decommissioning is necessary to minimize the personnel dose rates. In foreign countries, system decontaminations have been performed several times by applying the dilute organic chemical decontamination process. To prepare against the decommissioning of the nuclear power plant, it is necessary to develop the unique domestic chemical decontamination process.

  16. Modeling nucleation and coagulation modes in the formation of particulate matter inside a turbulent exhaust plume of a diesel engine.

    Science.gov (United States)

    Kim, Dong-Hee; Gautam, Mridul; Gera, Dinesh

    2002-05-01

    This paper presents the results from a study that is aimed at predicting the nucleation, coagulation, and dynamics of particulate matter (PM) emissions from on-road heavy-duty diesel vehicles. The PM concentration is predicted from the composition of fuel, and operating and ambient conditions. A numerical algorithm for simultaneously solving the coagulation, condensation, and nucleation equations is developed. The effect of relative humidity on the nucleation rate and the nucleus size is also discussed. In addition, the effect of the ambient air dilution on PM size distribution is numerically predicted for a diesel-powered truck operating in a controlled environment at NASA Langley wind-tunnel facility. The particle size distribution and concentration are measured at four different locations in a turbulent plume from the diesel exhaust in the tunnel, and an excellent agreement between the measured and predicted PM concentration values at these locations inside the tunnel is observed.

  17. Orbital Maneuvering Vehicle (OMV) plume and plume effects study

    Science.gov (United States)

    Smith, Sheldon D.

    1991-01-01

    The objective was to characterize the Orbital Maneuvering Vehicle (OMV) propulsion and attitude control system engine exhaust plumes and predict the resultant plume impingement pressure, heat loads, forces, and moments. Detailed description is provided of the OMV gaseous nitrogen (GN2) thruster exhaust plume flow field characteristics calculated with the RAMP2 snd SFPGEN computer codes. Brief descriptions are included of the two models, GN2 thruster characteristics and RAMP2 input data files. The RAMP2 flow field could be recalculated by other organizations using the information presented. The GN2 flow field can be readily used by other organizations who are interested in GN2 plume induced environments which require local flow field properties which can be supplied using the SFPGEN GN2 model.

  18. Ionic Liquids to Replace Hydrazine

    Science.gov (United States)

    Koelfgen, Syri; Sims, Joe; Forton, Melissa; Allan, Barry; Rogers, Robin; Shamshina, Julia

    2011-01-01

    A method for developing safe, easy-to-handle propellants has been developed based upon ionic liquids (ILs) or their eutectic mixtures. An IL is a binary combination of a typically organic cation and anion, which generally produces an ionic salt with a melting point below 100 deg C. Many ILs have melting points near, or even below, room temperature (room temperature ionic liquids, RTILs). More importantly, a number of ILs have a positive enthalpy of formation. This means the thermal energy released during decomposition reactions makes energetic ILs ideal for use as propellants. In this specific work, to date, a baseline set of energetic ILs has been identified, synthesized, and characterized. Many of the ILs in this set have excellent performance potential in their own right. In all, ten ILs were characterized for their enthalpy of formation, density, melting point, glass transition point (if applicable), and decomposition temperature. Enthalpy of formation was measured using a microcalorimeter designed specifically to test milligram amounts of energetic materials. Of the ten ILs characterized, five offer higher Isp performance than hydrazine, ranging between 10 and 113 seconds higher than the state-of-the-art propellant. To achieve this level of performance, the energetic cations 4- amino-l,2,4-triazolium and 3-amino-1,2,4-triazolium were paired with various anions in the nitrate, dicyanamide, chloride, and 3-nitro-l,2,4-triazole families. Protonation, alkylation, and butylation synthesis routes were used for creation of the different salts.

  19. Treatment for hydrazine-containing waste water solution

    Science.gov (United States)

    Yade, N.

    1986-01-01

    The treatment for waste solutions containing hydrazine is presented. The invention attempts oxidation and decomposition of hydrazine in waste water in a simple and effective processing. The method adds activated charcoal to waste solutions containing hydrazine while maintaining a pH value higher than 8, and adding iron salts if necessary. Then, the solution is aerated.

  20. Concentric-Electrode Organic Electrochemical Transistors: Case Study for Selective Hydrazine Sensing

    Directory of Open Access Journals (Sweden)

    Sébastien Pecqueur

    2017-03-01

    Full Text Available We report on hydrazine-sensing organic electrochemical transistors (OECTs with a design consisting of concentric annular electrodes. The design engineering of these OECTs was motivated by the great potential of using OECT sensing arrays in fields such as bioelectronics. In this work, poly(3,4-ethylenedioxythiophene:poly(styrenesulfonate (PEDOT:PSS-based OECTs have been studied as aqueous sensors that are specifically sensitive to the lethal hydrazine molecule. These amperometric sensors have many relevant features for the development of hydrazine sensors, such as a sensitivity down to 10−5 M of hydrazine in water, an order of magnitude higher selectivity for hydrazine than for nine other water-soluble common analytes, the capability to entirely recover its base signal after water flushing, and a very low operation voltage. The specificity for hydrazine to be sensed by our OECTs is caused by its catalytic oxidation at the gate electrode, and enables an increase in the output current modulation of the devices. This has permitted the device-geometry study of the whole series of 80 micrometric OECT devices with sub-20-nm PEDOT:PSS layers, channel lengths down to 1 µm, and a specific device geometry of coplanar and concentric electrodes. The numerous geometries unravel new aspects of the OECT mechanisms governing the electrochemical sensing behaviours of the device—more particularly the effect of the contacts which are inherent at the micro-scale. By lowering the device cross-talk, micrometric gate-integrated radial OECTs shall contribute to the diminishing of the readout invasiveness and therefore further promote the development of OECT biosensors.

  1. Concentric-Electrode Organic Electrochemical Transistors: Case Study for Selective Hydrazine Sensing

    Science.gov (United States)

    Pecqueur, Sébastien; Lenfant, Stéphane; Guérin, David; Alibart, Fabien; Vuillaume, Dominique

    2017-01-01

    We report on hydrazine-sensing organic electrochemical transistors (OECTs) with a design consisting of concentric annular electrodes. The design engineering of these OECTs was motivated by the great potential of using OECT sensing arrays in fields such as bioelectronics. In this work, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)-based OECTs have been studied as aqueous sensors that are specifically sensitive to the lethal hydrazine molecule. These amperometric sensors have many relevant features for the development of hydrazine sensors, such as a sensitivity down to 10−5 M of hydrazine in water, an order of magnitude higher selectivity for hydrazine than for nine other water-soluble common analytes, the capability to entirely recover its base signal after water flushing, and a very low operation voltage. The specificity for hydrazine to be sensed by our OECTs is caused by its catalytic oxidation at the gate electrode, and enables an increase in the output current modulation of the devices. This has permitted the device-geometry study of the whole series of 80 micrometric OECT devices with sub-20-nm PEDOT:PSS layers, channel lengths down to 1 µm, and a specific device geometry of coplanar and concentric electrodes. The numerous geometries unravel new aspects of the OECT mechanisms governing the electrochemical sensing behaviours of the device—more particularly the effect of the contacts which are inherent at the micro-scale. By lowering the device cross-talk, micrometric gate-integrated radial OECTs shall contribute to the diminishing of the readout invasiveness and therefore further promote the development of OECT biosensors. PMID:28287475

  2. Simpler valve for reciprocating engines

    Science.gov (United States)

    Akkerman, J. W.

    1978-01-01

    Simpler design eliminating camshafts, cams, and mechanical springs should improve reliability of hydrazine powered reciprocating engines. Valve is expected to improve efficiency, and reduce weight of engines in range up to 50 horsepower.

  3. Plume Diagnostics for Combustion Stability Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Sierra Engineering Inc. and Purdue University propose to develop a non-intrusive plume instrument capable of detecting and diagnosing combustion instability. This...

  4. Development of Emissions Measurement Techniques for Afterburning Turbine Engines. Supplement 2. Afterburner Plume Computer Program User’s Manual.

    Science.gov (United States)

    1975-10-01

    and total HC (as single- carbon-atom molecules) and total NO with sample water content as-sampled. ___— l B ’ ILllllpiM III... The composition and...hydrogen/carbon atom ratio. Absolute enthalpy of fuel, Btu/lbm. Water /air mass ratio in ambient air. Fan inlet total temperature, °R. Engine by-pass...IFtCQRE .>NO. C3RSTP) GO TO S IFISuPC .AND. SJPSIP) IFCMFR tANQ , HER3TP) GO TO 20 GU TO 5 GO TO JTCTRLOI JTCTRL02 JTCTRL03 JTXXRLM- RELÖCATE

  5. Hydrazine in the Ugi Tetrazole Reaction

    NARCIS (Netherlands)

    Patil, Pravin; Zhang, Ji; Kurpiewska, Katarzyna; Kalinowska-Tłuścik, Justyna; Dömling, Alexander

    2016-01-01

    We describe the hitherto unknown use of N-Boc-protected hydrazine in the Ugi tetrazole reaction to access a library of highly substituted 5-(hydrazinomethyl)-1-methyl-1H-tetrazoles. The reaction is very versatile and good to high yielding. A one-pot, two-step procedure is given.

  6. Digital filtering of plume emission spectra

    Science.gov (United States)

    Madzsar, George C.

    1990-01-01

    Fourier transformation and digital filtering techniques were used to separate the superpositioned spectral phenomena observed in the exhaust plumes of liquid propellant rocket engines. Space shuttle main engine (SSME) spectral data were used to show that extraction of spectral lines in the spatial frequency domain does not introduce error, and extraction of the background continuum introduces only minimal error. Error introduced during band extraction could not be quantified due to poor spectrometer resolution. Based on the atomic and molecular species found in the SSME plume, it was determined that spectrometer resolution must be 0.03 nm for SSME plume spectral monitoring.

  7. ASSESSMENT OF PLUME DIVING

    Science.gov (United States)

    This presentation presents an assessment of plume diving. Observations included: vertical plume delineation at East Patchogue, NY showed BTEX and MTBE plumes sinking on either side of a gravel pit; Lake Druid TCE plume sank beneath unlined drainage ditch; and aquifer recharge/dis...

  8. Crystal structure of hydrazine iron(III) phosphate, the first transition metal phosphate containing hydrazine.

    Science.gov (United States)

    David, Renald

    2015-12-01

    The title compound, poly[(μ2-hydrazine)(μ4-phosphato)iron(III)], [Fe(PO4)(N2H4)] n , was prepared under hydro-thermal conditions. Its asymmetric unit contains one Fe(III) atom located on an inversion centre, one P atom located on a twofold rotation axis, and two O, one N and two H atoms located on general positions. The Fe(III) atom is bound to four O atoms of symmetry-related PO4 tetra-hedra and to two N atoms of two symmetry-related hydrazine ligands, resulting in a slightly distorted FeO4N2 octa-hedron. The crystal structure consists of a three-dimensional hydrazine/iron phoshate framework whereby each PO4 tetra-hedron bridges four Fe(III) atoms and each hydrazine ligand bridges two Fe(III) atoms. The H atoms of the hydrazine ligands are also involved in moderate N-H⋯O hydrogen bonding with phosphate O atoms. The crystal structure is isotypic with the sulfates [Co(SO4)(N2H4)] and [Mn(SO4)(N2H4)].

  9. Crystal structure of hydrazine iron(III phosphate, the first transition metal phosphate containing hydrazine

    Directory of Open Access Journals (Sweden)

    Renald David

    2015-12-01

    Full Text Available The title compound, poly[(μ2-hydrazine(μ4-phosphatoiron(III], [Fe(PO4(N2H4]n, was prepared under hydrothermal conditions. Its asymmetric unit contains one FeIII atom located on an inversion centre, one P atom located on a twofold rotation axis, and two O, one N and two H atoms located on general positions. The FeIII atom is bound to four O atoms of symmetry-related PO4 tetrahedra and to two N atoms of two symmetry-related hydrazine ligands, resulting in a slightly distorted FeO4N2 octahedron. The crystal structure consists of a three-dimensional hydrazine/iron phoshate framework whereby each PO4 tetrahedron bridges four FeIII atoms and each hydrazine ligand bridges two FeIII atoms. The H atoms of the hydrazine ligands are also involved in moderate N—H...O hydrogen bonding with phosphate O atoms. The crystal structure is isotypic with the sulfates [Co(SO4(N2H4] and [Mn(SO4(N2H4].

  10. Chronic Inhalation Toxicity of Hydrazine: Oncogenic Effects

    Science.gov (United States)

    1981-06-01

    showed signs of anorexia and general fatigue. Changing diets and forced feedings resulted in the survival of the remaining two dogs. A 6-month chronic...Esophagus Bladder Stomach Seminal vesicles Duodenum Prostate Jejunum Testes Ileum Ovaries Cecum Uterus Colon Nasal cavity Rectum Brain Mesenteric lymph... malnutrition during chronic exposure. Based upon these studies, the current OSHA Threshold Limit Value of 1.0 ppm for hydrazine is unsatisfactory while the

  11. Skylon Aerodynamics and SABRE Plumes

    Science.gov (United States)

    Mehta, Unmeel; Afosmis, Michael; Bowles, Jeffrey; Pandya, Shishir

    2015-01-01

    An independent partial assessment is provided of the technical viability of the Skylon aerospace plane concept, developed by Reaction Engines Limited (REL). The objectives are to verify REL's engineering estimates of airframe aerodynamics during powered flight and to assess the impact of Synergetic Air-Breathing Rocket Engine (SABRE) plumes on the aft fuselage. Pressure lift and drag coefficients derived from simulations conducted with Euler equations for unpowered flight compare very well with those REL computed with engineering methods. The REL coefficients for powered flight are increasingly less acceptable as the freestream Mach number is increased beyond 8.5, because the engineering estimates did not account for the increasing favorable (in terms of drag and lift coefficients) effect of underexpanded rocket engine plumes on the aft fuselage. At Mach numbers greater than 8.5, the thermal environment around the aft fuselage is a known unknown-a potential design and/or performance risk issue. The adverse effects of shock waves on the aft fuselage and plumeinduced flow separation are other potential risks. The development of an operational reusable launcher from the Skylon concept necessitates the judicious use of a combination of engineering methods, advanced methods based on required physics or analytical fidelity, test data, and independent assessments.

  12. OPAD data analysis. [Optical Plumes Anomaly Detection

    Science.gov (United States)

    Buntine, Wray L.; Kraft, Richard; Whitaker, Kevin; Cooper, Anita E.; Powers, W. T.; Wallace, Tim L.

    1993-01-01

    Data obtained in the framework of an Optical Plume Anomaly Detection (OPAD) program intended to create a rocket engine health monitor based on spectrometric detections of anomalous atomic and molecular species in the exhaust plume are analyzed. The major results include techniques for handling data noise, methods for registration of spectra to wavelength, and a simple automatic process for estimating the metallic component of a spectrum.

  13. Numerical Studies on Fire-induced Thermal Plumes

    Institute of Scientific and Technical Information of China (English)

    Junmei LI; Yanfeng LI; Wan Ki CHOW; Huairong HUANG

    2005-01-01

    Most of the expressions describing fire plumes reported in the literature are known to be based on experiments.Due to different experimental methods, the geometry of the fire sources, fuel types and surrounding conditions, it is difficult to derive a comprehensive picture of a plume with its temperature and velocity fields on the basis of existing theoretical work. Computational Fluid Dynamics (CFD), which is regarded as a practical engineering tool in fire engineering by the experts, is sure to be able to give more details of the plume behavior under various situations. Aerodynamics for thermally-induced plumes will be studied numerically with CFD. Four typical axisymmetric plume equations will be assessed in this paper, and investigations will be useful for fire engineers in designing smoke management systems in an affordable fashion. This is a critical point in implementing engineering performance-based fire code.

  14. Simulation of 3-D Ultraviolet Radiation from Liquid Rocket Engine Plume%液体火箭发动机羽烟三维紫外辐射仿真研究

    Institute of Scientific and Technical Information of China (English)

    国爱燕; 唐义; 白廷柱; 黄刚

    2012-01-01

    针对液体火箭发动机羽烟紫外辐射的空间分布问题,建立三维数值计算模型.该模型采用标准κ-ε湍流模型和PDF模型仿真羽烟流场的状态参数,根据HITRAN数据库计算流场内吸收系数分布,并利用离散坐标法求解辐射传输方程,计算三维空间的紫外辐射分布.测试结果表明:三维紫外辐射模型的计算结果与实验数据一致,能够反应不同视角下液体火箭发动机羽烟紫外辐射强度的空间变化.%To analyze the spacial distribution of UV radiation from liquid rocket engine plume, a 3-D numerical model has been built. The standard κ -e model and probability density function (PDF) model were adopted to compute the flow-field properties of the plume. Combined with HITRAN database, the distribution of absorption coefficient was calculated, and the radiation transfer equation could be solved by the discrete ordinate method. Test results show that the 3-D computation model can provide numerical data that agree well with measured experimental data. It also could reflect the spacial distribution of UV radiation from the hydrogen-oxygen rocket engine plume at different angles of view.

  15. Engineering

    National Research Council Canada - National Science Library

    Includes papers in the following fields: Aerospace Engineering, Agricultural Engineering, Chemical Engineering, Civil Engineering, Electrical Engineering, Environmental Engineering, Industrial Engineering, Materials Engineering, Mechanical...

  16. Developing A New Sampling and Analysis Method for Hydrazine and Monomethyl Hydrazine

    Science.gov (United States)

    Allen, John R.

    2002-01-01

    Solid phase microextraction (SPME) will be used to develop a method for detecting monomethyl hydrazine (MMH) and hydrazine (Hz). A derivatizing agent, pentafluorobenzoyl chloride (PFBCl), is known to react readily with MMH and Hz. The SPME fiber can either be coated with PFBCl and introduced into a gaseous stream containing MMH, or PFBCl and MMH can react first in a syringe barrel and after a short equilibration period a SPME is used to sample the resulting solution. These methods were optimized and compared. Because Hz and MMH can degrade the SPME, letting the reaction occur first gave better results. Only MMH could be detected using either of these methods. Future research will concentrate on constructing calibration curves and determining the detection limit.

  17. Developing A New Sampling and Analysis Method for Hydrazine and Monomethyl Hydrazine

    Science.gov (United States)

    Allen, John R.

    2002-01-01

    Solid phase microextraction (SPME) will be used to develop a method for detecting monomethyl hydrazine (MMH) and hydrazine (Hz). A derivatizing agent, pentafluorobenzoyl chloride (PFBCl), is known to react readily with MMH and Hz. The SPME fiber can either be coated with PFBCl and introduced into a gaseous stream containing MMH, or PFBCl and MMH can react first in a syringe barrel and after a short equilibration period a SPME is used to sample the resulting solution. These methods were optimized and compared. Because Hz and MMH can degrade the SPME, letting the reaction occur first gave better results. Only MMH could be detected using either of these methods. Future research will concentrate on constructing calibration curves and determining the detection limit.

  18. Bacterial Toxicity and Metabolism of Three Hydrazine Fuels.

    Science.gov (United States)

    1980-09-01

    zine fuels have toxic effects on developing frog embryos and/or larvae. Hydrazine sulphate proved teratogenic at 40 milligrams per liter. MMH was...and for photographic developing . Hydrazine is also used as a surface active agent in plasticizer manufacturing (Reference 1). As of 1978, most...hour LC50 ranges for the common guppy of 0.6 to 4.6, 2.6 to 6.7, and 10.1 to 26.5 for hydrazine, MMH and UDMH, respectively. The range variation for

  19. Laser transmittance measurement technology on plume from solid-propellant engine%固体发动机羽烟的激光透过率测试

    Institute of Scientific and Technical Information of China (English)

    陈胜石; 宁子立; 欧秋晔; 陈文胜; 纪明; 高教波; 薛常佳

    2009-01-01

    为获得羽烟对激光透过率的影响,用烟箱法对2种配方的缩比发动机羽烟在1.06 μm、10.6 μm激光波段的透过率进行测试.采用1.064 μm激光调制发射、接收、数据采集系统对1.06 μm激光波段烟雾透过率测试;用黑体、光谱辐射计、数据采集系统可测出2 μm ~13 μm 的光学透过率,从中提出10.6 μm激光波段烟雾透过率,得到不同推进剂配方、不同烟雾浓度情况下10.6 μm光波和1.06 μm光波的烟雾透过率测试数据.烟箱1.8 m烟道上的测试数据表明:配方2推进剂优于配方1推进剂,10.6 μm光波的烟雾透过率96%~97%大于1.06 μm光波的烟雾透过率92%~93%.%The main performance of hyper-velocity kinetic missile and its solid propellants is described. The mechanism of laser attenuation caused by the plume of solid rocket motor is analyzed. The plume transmittance of two solid-propellant formulations was tested by the aid of a smoke-box when the laser wavebands were 1.06 μm and 10.6 μm. The plume transmittance in 1.06 μm laser was tested with 1.064 μm laser modulation emitting, receiving and data acqui-sition system. The plume transmittance of 10.6 μm laser was derived after the optical transmittance of 2 μm ~13 μm laser was tested with the blackbody radiation source, spectroradiometer and data acquisition system. The tested data indicates that formulation 2 is better than formulation 1, and the plume transmittance 96%~97% of 10.6 μm laser is higher than that 92%~93% of 1.06 μm laser.

  20. Synthesis and Free Radical Scavenging Activity of New Hydroxybenzylidene Hydrazines

    National Research Council Canada - National Science Library

    Frantisek Sersen; Fridrich Gregan; Peter Kotora; Jarmila Kmetova; Juraj Filo; Dusan Loos; Juraj Gregan

    2017-01-01

    Hydroxybenzylidene hydrazines exhibit a wide spectrum of biological activities. Here, we report synthesis and free radical scavenging activity of nine new N-(hydroxybenzylidene)-N′-[2,6-dinitro-4-(trifluoromethyl)]phenylhydrazines...

  1. Enthalpy of Formation of N2H4 (Hydrazine) Revisited

    Energy Technology Data Exchange (ETDEWEB)

    Feller, David; Bross, David H.; Ruscic, Branko

    2017-08-17

    In order to address the accuracy of the long-standing experimental enthalpy of formation of gas-phase hydrazine, fully confirmed in earlier versions of Active Thermochemical Tables (ATcT), the provenance of that value is re-examined in light of new high-end calculations of the Feller-Peterson-Dixon (FPD) variety. An overly optimistic determination of the vaporization enthalpy of hydrazine, which created an unrealistically strong connection between the gas phase thermochemistry and the calorimetric results defining the thermochemistry of liquid hydrazine was identified as the probable culprit. The new enthalpy of formation of gas-phase hydrazine, based on balancing all available knowledge, was determined to be 111.57 ± 0.47 kJ/mol at 0 K (97.41 kJ/mol at 298.15 K). Close agreement was found between the ATcT (even excluding the latest theoretical result) and FPD enthalpies.

  2. Mobility Spectrometer Studies on Hydrazine and Ammonia Detection

    Science.gov (United States)

    Niu, William; Eiceman, Gary; Szumlas, Andrew; Lewis, John

    2011-01-01

    An airborne vapor analyzer for detecting sub- to low- parts-per-million (ppm) hydrazine in the presence of higher concentration levels of ammonia has been under development for the Orion program. The detector is based on ambient pressure ionization and ion mobility characterization. The detector encompasses: 1) a membrane inlet to exclude particulate and aerosols from the analyzer inlet; 2) a method to separate hydrazine from ammonia which would otherwise lead to loss of calibration and quantitative accuracy for the hydrazine determination; and 3) response and quantitative determinations for both hydrazine and ammonia. Laboratory studies were made to explore some of these features including mobility measurements mindful of power, size, and weight issues. The study recommended the use of a mobility spectrometer of traditional design with a reagent gas and equipped with an inlet transfer line of bonded phase fused silica tube. The inlet transfer line provided gas phase separation of neutrals of ammonia from hydrazine at 50 C simplifying significantly the ionization chemistry that underlies response in a mobility spectrometer. Performance of the analyzer was acceptable between ranges of 30 to 80 C for both the pre-fractionation column and the drift tube. An inlet comprised of a combined membrane with valve-less injector allowed high speed quantitative determination of ammonia and hydrazine without cross reactivity from common metabolites such as alcohols, esters, and aldehydes. Preliminary test results and some of the design features are discussed.

  3. Solar Coronal Plumes

    Directory of Open Access Journals (Sweden)

    Giannina Poletto

    2015-12-01

    Full Text Available Polar plumes are thin long ray-like structures that project beyond the limb of the Sun polar regions, maintaining their identity over distances of several solar radii. Plumes have been first observed in white-light (WL images of the Sun, but, with the advent of the space era, they have been identified also in X-ray and UV wavelengths (XUV and, possibly, even in in situ data. This review traces the history of plumes, from the time they have been first imaged, to the complex means by which nowadays we attempt to reconstruct their 3-D structure. Spectroscopic techniques allowed us also to infer the physical parameters of plumes and estimate their electron and kinetic temperatures and their densities. However, perhaps the most interesting problem we need to solve is the role they cover in the solar wind origin and acceleration: Does the solar wind emanate from plumes or from the ambient coronal hole wherein they are embedded? Do plumes have a role in solar wind acceleration and mass loading? Answers to these questions are still somewhat ambiguous and theoretical modeling does not provide definite answers either. Recent data, with an unprecedented high spatial and temporal resolution, provide new information on the fine structure of plumes, their temporal evolution and relationship with other transient phenomena that may shed further light on these elusive features.

  4. Chemistry in aircraft plumes

    Energy Technology Data Exchange (ETDEWEB)

    Kraabol, A.G.; Stordal, F.; Knudsen, S. [Norwegian Inst. for Air Research, Kjeller (Norway); Konopka, P. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere

    1997-12-31

    An expanding plume model with chemistry has been used to study the chemical conversion of NO{sub x} to reservoir species in aircraft plumes. The heterogeneous conversion of N{sub 2}O{sub 5} to HNO{sub 3}(s) has been investigated when the emissions take place during night-time. The plume from an B747 has been simulated. During a ten-hour calculation the most important reservoir species was HNO{sub 3} for emissions at noon. The heterogeneous reactions had little impact on the chemical loss of NO{sub x} to reservoir species for emissions at night. (author) 4 refs.

  5. Experimental Study of the Plume Characteristics of an Aged Monopropellant Hydrazine Thruster

    Science.gov (United States)

    1979-04-01

    surfaces such as solar panels, thermal control coatings , and optical surfaces can degrade satellite performance. Experimental studies with regard... coated , fused silica lens onto the thruster axial centerline. The port through which the beam passed into the chamber was also made of fused silica. As...copper alone, beeswax melted onto the copper, and SEM quality Microstick ® glue dripped onto the copper and spread by moving the disks to and fro

  6. Plume Measurement System (PLUMES) Calibration Experiment

    Science.gov (United States)

    1994-08-01

    Atle Lohrmann SonTek, Inc. 7940 Silverton Avenue, No. 105 San Diego, California 92126 and Craig Huhta JIMAR University of Hawaii, Honolulu, Hawaii 96822...Measurement System (PLUMES) Calibration Experiment by Age Lohrmann SonTek, Inc. 7940 Silverton Avenue, No. 105 San Diego, CA 92126 Craig Huhta JIMAR...PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) &. PERFORMING ORGANIZATION SonTek, Inc., 7940 Silverton Avenue, No. 105, San Diego, CA 92126 REPORT NUMBER

  7. Hydrazine Borane and Hydrazinidoboranes as Chemical Hydrogen Storage Materials

    Directory of Open Access Journals (Sweden)

    Romain Moury

    2015-04-01

    Full Text Available Hydrazine borane N2H4BH3 and alkali derivatives (i.e., lithium, sodium and potassium hydrazinidoboranes MN2H3BH3 with M = Li, Na and K have been considered as potential chemical hydrogen storage materials. They belong to the family of boron- and nitrogen-based materials and the present article aims at providing a timely review while focusing on fundamentals so that their effective potential in the field could be appreciated. It stands out that, on the one hand, hydrazine borane, in aqueous solution, would be suitable for full dehydrogenation in hydrolytic conditions; the most attractive feature is the possibility to dehydrogenate, in addition to the BH3 group, the N2H4 moiety in the presence of an active and selective metal-based catalyst but for which further improvements are still necessary. However, the thermolytic dehydrogenation of hydrazine borane should be avoided because of the evolution of significant amounts of hydrazine and the formation of a shock-sensitive solid residue upon heating at >300 °C. On the other hand, the alkali hydrazinidoboranes, obtained by reaction of hydrazine borane with alkali hydrides, would be more suitable to thermolytic dehydrogenation, with improved properties in comparison to the parent borane. All of these aspects are surveyed herein and put into perspective.

  8. U. S. Air Force approach to plume contamination

    Science.gov (United States)

    Furstenau, Ronald P.; McCay, T. Dwayne; Mann, David M.

    1980-08-01

    Exhaust products from rocket engine firings can produce undesirable effects on sensitive satellite surfaces, such as optical systems, solar cells, and thermal control surfaces. The Air Force has an objective of minimizing the effect of rocket plume contamination on space-craft mission effectiveness. Plume contamination can result from solid rocket motors, liquid propellant engines, and electric thrusters. To solve the plume contamination problem, the Air Force Rocket Propulsion Laboratory (AFRPL) has developed a plume contamination computer model which predicts the production, transport, and deposition of rocket exhaust products. In addition, an experimental data base is being obtained through ground-based vacuum chamber experiments and in-flight measurements with which to compare the analytical results. Finally, the experimental data is being used to verify and improve the analytical model. The plume contamination model, known as CONTAM, has been used to make contamination predictions for various engines. The experimental programs have yielded quantitative data, such as species concentrations and temperatures, in all regions of the plume. The result of the modelling and experimental programs will ultimately be computer models which can be used by the satellite designer to analyze and to minimize the effect plume contamination will have on a particular spacecraft system.

  9. Three-dimensionally grown thorn-like Cu nanowire arrays by fully electrochemical nanoengineering for highly enhanced hydrazine oxidation

    Science.gov (United States)

    Huang, Jianfei; Zhao, Shunan; Chen, Wei; Zhou, Ying; Yang, Xiaoling; Zhu, Yihua; Li, Chunzhong

    2016-03-01

    This communication reports fully electrochemical nanoengineering toward three-dimensionally grown thorn-like Cu nanowire arrays (CNWAs) as a highly efficient and durable electrocatalyst for hydrazine oxidation. Characterized by substantial negative shifting of the onset potential and an enlarged catalytic current density, the CNWAs afforded greatly enhanced hydrazine oxidation activity, even transcending that of the Pt/C catalyst at a higher reaction rate. The parameters of the electrochemical engineering and metallization methods were found to be essentially influential on the microstructure, and thus the electrocatalytic activity of the CNWAs. The present work typifies a flexible and expandible route toward integrated electrodes of metallic 1D nanostructures which are of interest in advancing the performance of cutting-edge electrochemical applications.This communication reports fully electrochemical nanoengineering toward three-dimensionally grown thorn-like Cu nanowire arrays (CNWAs) as a highly efficient and durable electrocatalyst for hydrazine oxidation. Characterized by substantial negative shifting of the onset potential and an enlarged catalytic current density, the CNWAs afforded greatly enhanced hydrazine oxidation activity, even transcending that of the Pt/C catalyst at a higher reaction rate. The parameters of the electrochemical engineering and metallization methods were found to be essentially influential on the microstructure, and thus the electrocatalytic activity of the CNWAs. The present work typifies a flexible and expandible route toward integrated electrodes of metallic 1D nanostructures which are of interest in advancing the performance of cutting-edge electrochemical applications. Electronic supplementary information (ESI) available: Experimental details, additional figures and table. See DOI: 10.1039/c5nr06512g

  10. The Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFC Focused on Hanford’s 300 Area Uranium Plume Quality Assurance Project Plan

    Energy Technology Data Exchange (ETDEWEB)

    Fix, N. J.

    2008-01-31

    The purpose of the project is to conduct research at an Integrated Field-Scale Research Challenge Site in the Hanford Site 300 Area, CERCLA OU 300-FF-5 (Figure 1), to investigate multi-scale mass transfer processes associated with a subsurface uranium plume impacting both the vadose zone and groundwater. The project will investigate a series of science questions posed for research related to the effect of spatial heterogeneities, the importance of scale, coupled interactions between biogeochemical, hydrologic, and mass transfer processes, and measurements/approaches needed to characterize a mass-transfer dominated system. The research will be conducted by evaluating three (3) different hypotheses focused on multi-scale mass transfer processes in the vadose zone and groundwater, their influence on field-scale U(VI) biogeochemistry and transport, and their implications to natural systems and remediation. The project also includes goals to 1) provide relevant materials and field experimental opportunities for other ERSD researchers and 2) generate a lasting, accessible, and high-quality field experimental database that can be used by the scientific community for testing and validation of new conceptual and numerical models of subsurface reactive transport.

  11. Research on the Reaction Between Technetium and Hydrazine in Nitric Acid Medium

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The reaction between technetium and hydrazine in nitric acid medium was studied by the titration ofthe concentration of hydrazine and pursuing the concentration of heptavalent technetium along with time.It is approved that the reaction between technetium and hydrazine includes an inducing period, a fast

  12. Martian Atmospheric Plumes: Behavior, Detectability and Plume Tracing

    Science.gov (United States)

    Banfield, Don; Mischna, M.; Sykes, R.; Dissly, R.

    2013-10-01

    We will present our recent work simulating neutrally buoyant plumes in the martian atmosphere. This work is primarily directed at understanding the behavior of discrete plumes of biogenic tracer gases, and thus increasing our understanding of their detectability (both from orbit and from in situ measurements), and finally how to use the plumes to identify their precise source locations. We have modeled the detailed behavior of martian atmospheric plumes using MarsWRF for the atmospheric dynamics and SCIPUFF (a terrestrial state of the art plume modeling code that we have modified to represent martian conditions) for the plume dynamics. This combination of tools allows us to accurately simulate plumes not only from a regional scale from which an orbital observing platform would witness the plume, but also from an in situ perspective, with the instantaneous concentration variations that a turbulent flow would present to a point sampler in situ instrument. Our initial work has focused on the detectability of discrete plumes from an orbital perspective and we will present those results for a variety of notional orbital trace gas detection instruments. We have also begun simulating the behavior of the plumes from the perspective of a sampler on a rover within the martian atmospheric boundary layer. The detectability of plumes within the boundary layer has a very strong dependence on the atmospheric stability, with plume concentrations increasing by a factor of 10-1000 during nighttime when compared to daytime. In the equatorial regions of the planet where we have simulated plumes, the diurnal tidal “clocking” of the winds is strongly evident in the plume trail, which similarly “clocks” around its source. This behavior, combined with the strong diurnal concentration variations suggests that a rover hunting a plume source would be well suited to approach it from a particular azimuth (downwind at night) to maximize detectability of the plume and the ability to

  13. Positive ion chemistry in the exhaust plumes of an air craft jet engine and a burner: investigations with a quadrupole ion trap mass spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Kiendler, A.; Aberle, S.; Arnold, F. [Max Planck Institute for Nuclear Physics, Heidelberg (Germany). Atmospheric Physics Div.

    2000-07-01

    Using a quadrupole ion trap mass spectrometer detailed composition analyses were made of positive ions in the exhaust of an aircraft jet engine and of a jet fuel burner. For both scenarios complex organic ions with large mass numbers were most abundant. By employing the MS{sup 2}-mode of the quadrupole ion trap mass spectrometer, mass selected trapped ions were intendently broken up and characteristic fragment ions were observed. The latter indicate that the parent ions contain hydrogen, carbon and oxygen which is indicative of oxygenated hydrocarbons. This contrasts recent composition measurements of negative ions in aircraft jet engine exhaust made by our group which revealed that negative ions contain the inorganic acid H{sub 2}SO{sub 4}. Our present measurements support the view that positive ions in aircraft jet engine exhaust contain preferably organic molecules. (author)

  14. Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFRC Focused on Hanford’s 300 Area Uranium Plume

    Energy Technology Data Exchange (ETDEWEB)

    Zachara, John M.; Bjornstad, Bruce N.; Christensen, John N.; Conrad, Mark E.; Fredrickson, Jim K.; Freshley, Mark D.; Haggerty, Roy; Hammon, Glenn; Kent, Douglas B.; Konopka, Allan; Lichtner, Peter C.; Liu, Chongxuan; McKinley, James P.; Murray, Christopher J.; Rockhold, Mark L.; Rubin, Yoram; Vermeul, Vincent R.; Versteeg, Roelof J.; Ward, Anderson L.; Zheng, Chunmiao

    2010-02-01

    The Integrated Field-Scale Subsurface Research Challenge (IFRC) at the Hanford Site 300 Area uranium (U) plume addresses multi-scale mass transfer processes in a complex hydrogeologic setting where groundwater and riverwater interact. A series of forefront science questions on mass transfer are posed for research which relate to the effect of spatial heterogeneities; the importance of scale; coupled interactions between biogeochemical, hydrologic, and mass transfer processes; and measurements and approaches needed to characterize and model a mass-transfer dominated system. The project was initiated in February 2007, with CY 2007 and CY 2008 progress summarized in preceding reports. The site has 35 instrumented wells, and an extensive monitoring system. It includes a deep borehole for microbiologic and biogeochemical research that sampled the entire thickness of the unconfined 300 A aquifer. Significant, impactful progress has been made in CY 2009 with completion of extensive laboratory measurements on field sediments, field hydrologic and geophysical characterization, four field experiments, and modeling. The laboratory characterization results are being subjected to geostatistical analyses to develop spatial heterogeneity models of U concentration and chemical, physical, and hydrologic properties needed for reactive transport modeling. The field experiments focused on: (1) physical characterization of the groundwater flow field during a period of stable hydrologic conditions in early spring, (2) comprehensive groundwater monitoring during spring to characterize the release of U(VI) from the lower vadose zone to the aquifer during water table rise and fall, (3) dynamic geophysical monitoring of salt-plume migration during summer, and (4) a U reactive tracer experiment (desorption) during the fall. Geophysical characterization of the well field was completed using the down-well Electrical Resistance Tomography (ERT) array, with results subjected to robust

  15. Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFRC Focused on Hanford’s 300 Area Uranium Plume January 2010 to January 2011

    Energy Technology Data Exchange (ETDEWEB)

    Zachara, John M.; Bjornstad, Bruce N.; Christensen, John N.; Conrad, Mark S.; Fredrickson, Jim K.; Freshley, Mark D.; Haggerty, Roy; Hammond, Glenn E.; Kent, Douglas B.; Konopka, Allan; Lichtner, Peter C.; Liu, Chongxuan; McKinley, James P.; Murray, Christopher J.; Rockhold, Mark L.; Rubin, Yoram; Vermeul, Vincent R.; Versteeg, Roelof J.; Ward, Anderson L.; Zheng, Chunmiao

    2011-02-01

    The Integrated Field Research Challenge (IFRC) at the Hanford Site 300 Area uranium (U) plume addresses multi-scale mass transfer processes in a complex subsurface hydrogeologic setting where groundwater and riverwater interact. A series of forefront science questions on reactive mass transfer focus research. These questions relate to the effect of spatial heterogeneities; the importance of scale; coupled interactions between biogeochemical, hydrologic, and mass transfer processes; and measurements and approaches needed to characterize and model a mass-transfer dominated system. The project was initiated in February 2007, with CY 2007, CY 2008, and CY 2009 progress summarized in preceding reports. A project peer review was held in March 2010, and the IFRC project has responded to all suggestions and recommendations made in consequence by reviewers and SBR/DOE. These responses have included the development of “Modeling” and “Well-Field Mitigation” plans that are now posted on the Hanford IFRC web-site. The site has 35 instrumented wells, and an extensive monitoring system. It includes a deep borehole for microbiologic and biogeochemical research that sampled the entire thickness of the unconfined 300 A aquifer. Significant, impactful progress has been made in CY 2010 including the quantification of well-bore flows in the fully screened wells and the testing of means to mitigate them; the development of site geostatistical models of hydrologic and geochemical properties including the distribution of U; developing and parameterizing a reactive transport model of the smear zone that supplies contaminant U to the groundwater plume; performance of a second passive experiment of the spring water table rise and fall event with a associated multi-point tracer test; performance of downhole biogeochemical experiments where colonization substrates and discrete water and gas samplers were deployed to the lower aquifer zone; and modeling of past injection experiments for

  16. Unsteady turbulent buoyant plumes

    CERN Document Server

    Woodhouse, Mark J; Hogg, Andrew J

    2015-01-01

    We model the unsteady evolution of turbulent buoyant plumes following temporal changes to the source conditions. The integral model is derived from radial integration of the governing equations expressing the conservation of mass, axial momentum and buoyancy. The non-uniform radial profiles of the axial velocity and density deficit in the plume are explicitly described by shape factors in the integral equations; the commonly-assumed top-hat profiles lead to shape factors equal to unity. The resultant model is hyperbolic when the momentum shape factor, determined from the radial profile of the mean axial velocity, differs from unity. The solutions of the model when source conditions are maintained at constant values retain the form of the well-established steady plume solutions. We demonstrate that the inclusion of a momentum shape factor that differs from unity leads to a well-posed integral model. Therefore, our model does not exhibit the mathematical pathologies that appear in previously proposed unsteady i...

  17. Plumes Do Not Exist

    Science.gov (United States)

    Hamilton, W. B.; Anderson, D. L.; Foulger, G. R.; Winterer, E. L.

    Hypothetical plumes from the deep mantle are widely assumed to provide an abso- lute hotspot reference frame, inaugurate rifting, drive plates, and profoundly influence magmatic and tectonic evolution of oceans and continents. Many papers on local to global tectonics, magmatism, and geochemistry invoke plumes, and assign to the man- tle whatever properties, dynamics, and composition are needed to enable them. The fixed-plume concept arose from the Emperor-Hawaii seamount-and-island province, the 45 Ma inflection in which was assumed to record a 60-degree change in direction by the Pacific plate. Paleomagnetic latitudes and smooth Pacific spreading patterns show that such a change did not occur. Other Pacific chains once assumed to be syn- chronous with, and Euler-parallel to, Hawaii have proved to be neither. Thermal and physical properties of Hawaiian lithosphere falsify plume predictions. Rationales for fixed hotspots elsewhere also have become untenable as databases enlarged. Astheno- sphere is everywhere near solidus temperature, so buoyant melt does not require a local heat source but, rather, needs a thin roof or crack or tensional setting for egress. MORB and ocean-island basalt (OIB) broadly intergrade in composition, but MORB typically is richer in refractory elements and their radiogenic daughters, whereas OIB commonly is richer in fusible elements and their daughters. MORB and OIB contrasts are required by melt behavior and do not indicate unlike source reservoirs. MORB melts rise, with minimal reaction, through hot asthenosphere, whereas OIB melts re- act, and thereby lose substance, by crystallizing refractories and retaining and assim- ilating subordinate fusibles, with thick, cool lithosphere and crust. There is no need for hypotheses involving chaotic plume behavior or thousands of km of lateral flow of plume material, nor for postulates of SprimitiveT lower mantle contrary to cos- & cedil;mological and thermodynamic considerations. Plume

  18. Where Plumes Live

    Science.gov (United States)

    King, S. D.

    2004-12-01

    From the perspective of fluid dynamics, `Plumes or not?' might be the wrong question. Let me begin by defining a few terms. Plume with a `P' is the well-known thermal structure with thin (order 100 km) tail and large, bulbous head that originates at the core-mantle boundary. The thin tail/large, bulbous-head morphology has been generated in a number of laboratory and numerical experiments. It can be seen, for example, on the cover of the famous fluid dynamics text by Batchelor. There is a clearly-defined range of parameters for which this structure is the preferred solution for instabilities arising from a bottom boundary layer in a convecting fluid. For example, a strong temperature-dependent rheology is needed. By contrast, plume with a `p' is any cylindrical or quasi-cylindrical instability originating from a thermal (or thermo-chemical) boundary layer. In fluid dynamics plume is sometimes used interchangeable with jet. Unless there is a very small temperature drop across the core-mantle boundary or a rather remarkable balance between temperature and composition at the base of the mantle, there are almost certainly plumes. (Note the little p.) Are these plumes the thermal structures with thin (order 100 km) tails and large bulbous heads or could they be broad, hot regions such as the degree 2 pattern seen in global seismic tomography images of the lower mantle, or the disconnected droplets seen in chaotic convection? To study this question, I will present a sequence of numerical `experiments' that illustrate the morphology of instabilities from a basal thermal boundary layer, i.e., plumes. Some of the aspects I will present include: spherical geometry, temperature-and pressure-dependence of rheology, internal heating, pressure-dependent coefficient of thermal expansion, variable coefficient of thermal diffusivity, phase transformations, and compositional layering at the base of the mantle. The goal is to map out the parameters and conditions where Plumes live

  19. Dilution in Transition Zone between Rising Plumes and Surface Plumes

    DEFF Research Database (Denmark)

    Larsen, Torben

    2004-01-01

    The papers presents some physical experiments with the dilution of sea outfall plumes with emphasize on the transition zone where the relative fast flowing vertical plume turns to a horizontal surface plume following the slow sea surface currents. The experiments show that a considerable dilution...

  20. Standoff midwave infrared hyperspectral imaging of ship plumes

    Science.gov (United States)

    Gagnon, Marc-André; Gagnon, Jean-Philippe; Tremblay, Pierre; Savary, Simon; Farley, Vincent; Guyot, Éric; Lagueux, Philippe; Chamberland, Martin; Marcotte, Frédérick

    2016-05-01

    Characterization of ship plumes is very challenging due to the great variety of ships, fuel, and fuel grades, as well as the extent of a gas plume. In this work, imaging of ship plumes from an operating ferry boat was carried out using standoff midwave (3-5 μm) infrared hyperspectral imaging. Quantitative chemical imaging of combustion gases was achieved by fitting a radiative transfer model. Combustion efficiency maps and mass flow rates are presented for carbon monoxide (CO) and carbon dioxide (CO2). The results illustrate how valuable information about the combustion process of a ship engine can be successfully obtained using passive hyperspectral remote sensing imaging.

  1. Turbulent buoyant jets and plumes

    CERN Document Server

    Rodi, Wolfgang

    The Science & Applications of Heat and Mass Transfer: Reports, Reviews, & Computer Programs, Volume 6: Turbulent Buoyant Jets and Plumes focuses on the formation, properties, characteristics, and reactions of turbulent jets and plumes. The selection first offers information on the mechanics of turbulent buoyant jets and plumes and turbulent buoyant jets in shallow fluid layers. Discussions focus on submerged buoyant jets into shallow fluid, horizontal surface or interface jets into shallow layers, fundamental considerations, and turbulent buoyant jets (forced plumes). The manuscript then exami

  2. On predicting mantle mushroom plumes

    Directory of Open Access Journals (Sweden)

    Ka-Kheng Tan

    2011-04-01

    Top cooling may produce plunging plumes of diameter of 585 km and at least 195 Myr old. The number of cold plumes is estimated to be 569, which has not been observed by seismic tomography or as cold spots. The cold plunging plumes may overwhelm and entrap some of the hot rising plumes from CMB, so that together they may settle in the transition zone.

  3. Ultraviolet surface plasmon-mediated low temperature hydrazine decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Siying; Sheldon, Matthew T.; Atwater, Harry A. [Thomas J. Watson Laboratories of Applied Physics, California Institute of Technology, Pasadena, California 91125 (United States); Liu, Wei-Guang; Jaramillo-Botero, Andres; Goddard, William Andrew [Materials and Process Simulation Center, California Institute of Technology, Pasadena, California 91125 (United States)

    2015-01-12

    Conventional methods require elevated temperatures in order to dissociate high-energy nitrogen bonds in precursor molecules such as ammonia or hydrazine used for nitride film growth. We report enhanced photodissociation of surface-absorbed hydrazine (N{sub 2}H{sub 4}) molecules at low temperature by using ultraviolet surface plasmons to concentrate the exciting radiation. Plasmonic nanostructured aluminum substrates were designed to provide resonant near field concentration at λ = 248 nm (5 eV), corresponding to the maximum optical cross section for hydrogen abstraction from N{sub 2}H{sub 4}. We employed nanoimprint lithography to fabricate 1 mm × 1 mm arrays of the resonant plasmonic structures, and ultraviolet reflectance spectroscopy confirmed resonant extinction at 248 nm. Hydrazine was cryogenically adsorbed to the plasmonic substrate in a low-pressure ambient, and 5 eV surface plasmons were resonantly excited using a pulsed KrF laser. Mass spectrometry was used to characterize the photodissociation products and indicated a 6.2× overall enhancement in photodissociation yield for hydrazine adsorbed on plasmonic substrates compared with control substrates. The ultraviolet surface plasmon enhanced photodissociation demonstrated here may provide a valuable method to generate reactive precursors for deposition of nitride thin film materials at low temperatures.

  4. Thermal plumes in ventilated rooms

    DEFF Research Database (Denmark)

    Kofoed, Peter; Nielsen, Peter V.

    1990-01-01

    The design of a displacement ventilation system involves determination of the flow rate in the thermal plumes. The flow rate in the plumes and the vertical temperature gradient influence each other, and they are influenced by many factors. This paper shows some descriptions of these effects. Free...... to be the only possible approach to obtain the volume flow in: thermal plumes in ventilated rooms....

  5. 氢氧火箭发动机射流仿真与试验台热防护%Thermal Protection and Plume Simulation for Hydrogen/Oxygen Rocket Engine Test Stage

    Institute of Scientific and Technical Information of China (English)

    李茂; 王占林

    2014-01-01

    The plume characteristics of the hydrogen/oxygen rocket engine were studied with the method of CFD ( computational fluid dynamics ) .The influences of the geometry model , the combus-tion model and the turbulence model on the characteristics of the combustion flowfield were ana-lyzed .The results from the numerical simulation were compared with those from the experiments qualitatively and quantitatively .Based on the distributions of the temperature from the numerical simulation results in the different tests , the armor plate was designed for the thermal protection and applied for the test stage .It is confirmed that the approach is effective and reliable .%采用计算流体方法获得氢氧火箭发动机地面试验射流特征,开展了几何模型、燃烧模型和湍流模型对射流场的影响分析以及与试验结果的定性和定量对比。依据不同试验模式下的射流场温度的数值分布,提出试验台钢板防护方案并进行防护,试验证明方案可靠有效。

  6. A plume spectroscopy system for flight applications

    Science.gov (United States)

    Makel, D. B.; Petersen, T. V.; Duncan, D. B.; Madzsar, G. C.

    1993-06-01

    An operational plume spectroscopy system will be an important element of any rocket engine health management system (HMS). The flight capable FPI spectrometer will enable prognosis and response to incipient rocket engine failures as well as diagnosis of wear and degradation for on-condition maintenance. Spectrometer application to development programs, such as the Space Lifter, NASP, and SSTO, will reduce program risks, allow better adherence to schedules and save money by reducing or eliminating redesign and test costs. The diagnostic capability of a proven, calibrated spectrometer will enhance post-burn certification of high value, reusable engines, such as the Space Shuttle Main Engine (SSME), where life and reliability are key cost drivers. This paper describes a prototype FPI spectrometer for demonstration and validation testing on NASA's Technology Test Bed Engine (TTBE) at Marshall Space Flight Center. The TTBE test unit is designed with flight prototype optics and a commercial off-the-shelf data processing system.

  7. Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFRC Focused on Hanford’s 300 Area Uranium Plume January 2011 to January 2012

    Energy Technology Data Exchange (ETDEWEB)

    Zachara, John M.; Bjornstad, Bruce N.; Christensen, John N.; Conrad, Mark S.; Fredrickson, Jim K.; Freshley, Mark D.; Haggerty, Roy; Hammond, Glenn E.; Kent, Douglas B.; Konopka, Allan; Lichtner, Peter C.; Liu, Chongxuan; McKinley, James P.; Murray, Christopher J.; Rockhold, Mark L.; Rubin, Yoram; Vermeul, Vincent R.; Versteeg, Roelof J.; Zheng, Chunmiao

    2012-03-05

    The Integrated Field Research Challenge (IFRC) at the Hanford Site 300 Area uranium (U) plume addresses multi-scale mass transfer processes in a complex subsurface biogeochemical setting where groundwater and riverwater interact. A series of forefront science questions on reactive mass transfer motivates research. These questions relate to the effect of spatial heterogeneities; the importance of scale; coupled interactions between biogeochemical, hydrologic, and mass transfer processes; and measurements and approaches needed to characterize and model a mass-transfer dominated biogeochemical system. The project was initiated in February 2007, with CY 2007, CY 2008, CY 2009, and CY 2010 progress summarized in preceding reports. A project peer review was held in March 2010, and the IFRC project acted upon all suggestions and recommendations made in consequence by reviewers and SBR/DOE. These responses have included the development of 'Modeling' and 'Well-Field Mitigation' plans that are now posted on the Hanford IFRC web-site, and modifications to the IFRC well-field completed in CY 2011. The site has 35 instrumented wells, and an extensive monitoring system. It includes a deep borehole for microbiologic and biogeochemical research that sampled the entire thickness of the unconfined 300 A aquifer. Significant, impactful progress has been made in CY 2011 including: (i) well modifications to eliminate well-bore flows, (ii) hydrologic testing of the modified well-field and upper aquifer, (iii) geophysical monitoring of winter precipitation infiltration through the U-contaminated vadose zone and spring river water intrusion to the IFRC, (iv) injection experimentation to probe the lower vadose zone and to evaluate the transport behavior of high U concentrations, (v) extended passive monitoring during the period of water table rise and fall, and (vi) collaborative down-hole experimentation with the PNNL SFA on the biogeochemistry of the 300 A Hanford

  8. A computational scheme usable for calculating the plume backflow region

    Science.gov (United States)

    Cooper, B. P., Jr.

    1978-01-01

    The effects of the nozzle wall boundary layer on the plume flowfield are neglected in the majority of computational schemes which exist for the calculation of rocket engine exhaust plume flowfields. This neglect, which is unimportant in many applications, becomes unacceptable for applications where a surface which can be adversely affected by plume impingement forces, heating, or contamination is located behind the nozzle exit plane in what is called the 'plume backflow region'. The flow in this region originates in, and is highly affected by, the nozzle wall boundary layer. The inclusion of the effects of the boundary layer in the calculations is required for an appropriate determination of the flowfield properties within this region. A description is presented of the results of modifications of a method-of-characteristics computer program. The modifications were made to include the effects of the nozzle wall boundary layer on the plume flowfield. A comparison of computed and experimental data indicates that the employed computer program may be a useful tool for calculating the entire plume flowfield for liquid propellant rocket engines.

  9. Numerical Modelling of Jets and Plumes

    DEFF Research Database (Denmark)

    Larsen, Torben

    1993-01-01

    An overview on numerical models for prediction of the flow and mixing processes in turbulent jets and plumes is given. The overview is structured to follow an increasing complexity in the physical and numerical principles. The various types of models are briefly mentioned, from the one-dimensiona......An overview on numerical models for prediction of the flow and mixing processes in turbulent jets and plumes is given. The overview is structured to follow an increasing complexity in the physical and numerical principles. The various types of models are briefly mentioned, from the one......-dimensional integral method to the general 3-dimensional solution of the Navier-Stokes equations. Also the predictive capabilities of the models are discussed. The presentation takes the perspective of civil engineering and covers issues like sewage outfalls and cooling water discharges to the sea....

  10. A Lagrangian Approach to Studying Instantaneous Plume Dispersion and Concentration Fluctations

    Science.gov (United States)

    2007-11-02

    liquid PMCH from a reservoir (a medical IV bag), through a hypodermic needle , and onto a hotplate located within the duct. The temperature of the...plume theory in which time-averaged dispersion is the result of plume meander and relative plume diffusion (Gifford 1959). Wind data near release height...Science Degree will be completed in Environmental Engineering, 1998). Note: Mark only assisted in fieldwork and data analysis during one month of the

  11. A case for mantle plumes

    Institute of Scientific and Technical Information of China (English)

    Geoffrey F. Davies

    2005-01-01

    The existence of at least several plumes in the Earth's mantle can be inferred with few assumptions from well-established observations. As well, thermal mantle plumes can be predicted from well-established and quantified fluid dynamics and a plausible assumption about the Earth's early thermal state. Some additional important observations, especially of flood basalts and rift-related magmatism, have been shown to be plausibly consistent with the physical theory. Recent claims to have detected plumes using seismic tomography may comprise the most direct evidence for plumes, but plume tails are likely to be difficult to resolve definitively and the claims need to be well tested. Although significant questions remain about its viability, the plume hypothesis thus seems to be well worth continued investigation. Nevertheless there are many non-plate-related magmatic phenomena whose association with plumes is unclear or unlikely. Compositional buoyancy has recently been shown potentially to substantially complicate the dynamics of plumes, and this may lead to explanations for a wider range of phenomena, including "headless" hotspot tracks, than purely thermal plumes.

  12. Mantle plumes and continental tectonics.

    Science.gov (United States)

    Hill, R I; Campbell, I H; Davies, G F; Griffiths, R W

    1992-04-10

    Mantle plumes and plate tectonics, the result of two distinct modes of convection within the Earth, operate largely independently. Although plumes are secondary in terms of heat transport, they have probably played an important role in continental geology. A new plume starts with a large spherical head that can cause uplift and flood basalt volcanism, and may be responsible for regional-scale metamorphism or crustal melting and varying amounts of crustal extension. Plume heads are followed by narrow tails that give rise to the familiar hot-spot tracks. The cumulative effect of processes associated with tail volcanism may also significantly affect continental crust.

  13. Terrestrial Plume Impingement Testbed Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Masten Space Systems proposes to create a terrestrial plume impingement testbed for generating novel datasets for extraterrestrial robotic missions. This testbed...

  14. Developing a New Sampling And Analysis Method For Hydrazine And Monomethyl Hydrazine: Using a Derivatizing Agent With Solid Phase Microextraction

    Science.gov (United States)

    Allen, John

    2001-01-01

    Solid phase microextraction (SPME) will be used to develop a method for detecting monomethyl hydrazine (MMH) and hydrazine (Hz). A derivatizing agent, pentafluorobenzoyl chloride (PFBCI), is known to react readily with MMH and Hz. The SPME fiber can either be coated with PFBCl and introduced into a gaseous stream containing MMH, or PFBCl and MMH can react first in a syringe barrel and after a short equilibration period a SPME is used to sample the resulting solution. These methods were optimized and compared. Because Hz and MMH can degrade the SPME, letting the reaction occur first gave better results. Only MMH could be detected using either of these methods. Future research will concentrate on constructing calibration curves and determining the detection limit.

  15. Developing a New Sampling And Analysis Method For Hydrazine And Monomethyl Hydrazine: Using a Derivatizing Agent With Solid Phase Microextraction

    Science.gov (United States)

    Allen, John

    2001-01-01

    Solid phase microextraction (SPME) will be used to develop a method for detecting monomethyl hydrazine (MMH) and hydrazine (Hz). A derivatizing agent, pentafluorobenzoyl chloride (PFBCI), is known to react readily with MMH and Hz. The SPME fiber can either be coated with PFBCl and introduced into a gaseous stream containing MMH, or PFBCl and MMH can react first in a syringe barrel and after a short equilibration period a SPME is used to sample the resulting solution. These methods were optimized and compared. Because Hz and MMH can degrade the SPME, letting the reaction occur first gave better results. Only MMH could be detected using either of these methods. Future research will concentrate on constructing calibration curves and determining the detection limit.

  16. Evaluation of hydrazine reduction by cellulose acetate filters using infrared tunable diode laser spectroscopy.

    Science.gov (United States)

    Harward, Charles N; Parrish, Milton E; Plunkett, Susan E; Banyasz, Joseph L; Shafer, Kenneth H

    2002-11-15

    Cellulose acetate (CA) filters have been investigated to determine their hydrazine (N2H4) breakthrough characteristics using a system based on tunable diode laser absorption spectroscopy (TDIAS). The breakthrough mass loading sorption curves for hydrazine were dependent on both the flow rate and the concentration. In experiments using a 4.5 ppmv hydrazine standard, the amounts of hydrazine retained by the CA filter were 4.25 microg at a flow rate of 2.82 L/min and 65 microg at a flow rate of 0.28 L/min. These loadings are much greater than the 31.5 ng/cigarette of hydrazine reported in smoke for unfiltered cigarettes. Further, CA filters exposed to four and eight puffs of smoke actually made the filter more efficient in retaining hydrazine compared to CA filters that had not been exposed to smoke. Therefore, if hydrazine is present in smoke at the levels reported in unfiltered cigarettes, all of the hydrazine would be trapped by the CA filter, and would be unable to break through during smoking. A unique feature of this analytical method is that the instrument does not require calibration after molecular parameters have been determined, in this case from previously acquired quantitative hydrazine FT-IR reference spectra.

  17. Fabrication of liquid crystal based sensor for detection of hydrazine vapours

    Science.gov (United States)

    Nandi, Rajib; Singh, Sachin Kumar; Singh, Hemant Kumar; Singh, Bachcha; Singh, Ranjan K.

    2014-10-01

    A novel liquid crystal (LC) based sensor to detect trace level amount of hydrazine vapour has been developed. The LC 4‧-pentyl-4-biphenylcarbonitrile (5CB) doped with 0.5 wt% 4-decyloxy benzaldehyde (DBA) shows dark to bright optical texture upon exposure of hydrazine vapours as revealed by polarizing optical microscopy under crossed polarizers. The hydrazine interacts with the doped DBA and form diimine compound which disrupt the orientation of aligned 5CB. The interaction between DBA and hydrazine has been also studied by Raman spectroscopy.

  18. SSME Condition Monitoring Using Neural Networks and Plume Spectral Signatures

    Science.gov (United States)

    Hopkins, Randall; Benzing, Daniel

    1996-01-01

    For a variety of reasons, condition monitoring of the Space Shuttle Main Engine (SSME) has become an important concern for both ground tests and in-flight operation. The complexities of the SSME suggest that active, real-time condition monitoring should be performed to avoid large-scale or catastrophic failure of the engine. In 1986, the SSME became the subject of a plume emission spectroscopy project at NASA's Marshall Space Flight Center (MSFC). Since then, plume emission spectroscopy has recorded many nominal tests and the qualitative spectral features of the SSME plume are now well established. Significant discoveries made with both wide-band and narrow-band plume emission spectroscopy systems led MSFC to develop the Optical Plume Anomaly Detection (OPAD) system. The OPAD system is designed to provide condition monitoring of the SSME during ground-level testing. The operational health of the engine is achieved through the acquisition of spectrally resolved plume emissions and the subsequent identification of abnormal emission levels in the plume indicative of engine erosion or component failure. Eventually, OPAD, or a derivative of the technology, could find its way on to an actual space vehicle and provide in-flight engine condition monitoring. This technology step, however, will require miniaturized hardware capable of processing plume spectral data in real-time. An objective of OPAD condition monitoring is to determine how much of an element is present in the SSME plume. The basic premise is that by knowing the element and its concentration, this could be related back to the health of components within the engine. For example, an abnormal amount of silver in the plume might signify increased wear or deterioration of a particular bearing in the engine. Once an anomaly is identified, the engine could be shut down before catastrophic failure occurs. Currently, element concentrations in the plume are determined iteratively with the help of a non-linear computer

  19. Analyzing rocket plume spectral data with neural networks

    Science.gov (United States)

    Whitaker, Kevin W.; Krishnakumar, K. S.; Benzing, Daniel A.

    1995-01-01

    The Optical Plume Anomaly Detection (OPAD) system is under development to provide early-warning failure detection in support of ground-level testing of the Space Shuttle Main Engine (SSME). Failure detection is to be achieved through the acquisition of spectrally resolved plume emissions and subsequent identification of abnormal levels indicative of engine corrosion or component failure. Two computer codes (one linear and the other non-linear) are used by the OPAD system to iteratively determine specific element concentrations in the SSME plume, given emission intensity and wavelength information. Since this analysis is extremely labor intensive, a study was initiated to develop neural networks that would model the 'inverse' of these computer codes. Optimally connected feed-forward networks with imperceptible prediction error have been developed for each element modeled by the linear code, SPECTRA4. Radial basis function networks were developed for the non-linear code, SPECTRA5, and predict combustion temperature in addition to element concentrations.

  20. Analyzing rocket plume spectral data with neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, K.W.; Krishnakumar, K.S.; Benzing, D.A.

    1995-09-01

    The Optical Plume Anomaly Detection (OPAD) system is under development to provide early-warning failure detection in support of ground-level testing of the Space Shuttle Main Engine (SSME). Failure detection is to be achieved through the acquisition of spectrally resolved plume emissions and subsequent identification of abnormal levels indicative of engine corrosion or component failure. Two computer codes (one linear and the other non-linear) are used by the OPAD system to iteratively determine specific element concentrations in the SSME plume, given emission intensity and wavelength information. Since this analysis is extremely labor intensive, a study was initiated to develop neural networks that would model the `inverse` of these computer codes. Optimally connected feed-forward networks with imperceptible prediction error have been developed for each element modeled by the linear code, SPECTRA4. Radial basis function networks were developed for the non-linear code, SPECTRA5, and predict combustion temperature in addition to element concentrations.

  1. Analyzing rocket plume spectral data with neural networks

    Science.gov (United States)

    Whitaker, Kevin W.; Krishnakumar, K. S.; Benzing, Daniel A.

    The Optical Plume Anomaly Detection (OPAD) system is under development to provide early-warning failure detection in support of ground-level testing of the Space Shuttle Main Engine (SSME). Failure detection is to be achieved through the acquisition of spectrally resolved plume emissions and subsequent identification of abnormal levels indicative of engine corrosion or component failure. Two computer codes (one linear and the other non-linear) are used by the OPAD system to iteratively determine specific element concentrations in the SSME plume, given emission intensity and wavelength information. Since this analysis is extremely labor intensive, a study was initiated to develop neural networks that would model the 'inverse' of these computer codes. Optimally connected feed-forward networks with imperceptible prediction error have been developed for each element modeled by the linear code, SPECTRA4. Radial basis function networks were developed for the non-linear code, SPECTRA5, and predict combustion temperature in addition to element concentrations.

  2. Dilution of Buoyant Surface Plumes

    DEFF Research Database (Denmark)

    Larsen, Torben; Petersen, Ole

    The purpose of present work is to establish a quantitative description of a surface plume which is valid for the range of density differences occurring in relation to sewage outfalls.......The purpose of present work is to establish a quantitative description of a surface plume which is valid for the range of density differences occurring in relation to sewage outfalls....

  3. Thermal Plumes in Ventilated Rooms

    DEFF Research Database (Denmark)

    Kofoed, Peter; Nielsen, Peter V.

    The design of a displacement ventilation system involves determination of the flow rate in the thermal plumes. The flow rate in the plumes and the vertical temperature gradient influence each other, and they are influenced by many factors. This paper shows some descriptions of these effects....

  4. Atmospheric chemistry in volcanic plumes.

    Science.gov (United States)

    von Glasow, Roland

    2010-04-13

    Recent field observations have shown that the atmospheric plumes of quiescently degassing volcanoes are chemically very active, pointing to the role of chemical cycles involving halogen species and heterogeneous reactions on aerosol particles that have previously been unexplored for this type of volcanic plumes. Key features of these measurements can be reproduced by numerical models such as the one employed in this study. The model shows sustained high levels of reactive bromine in the plume, leading to extensive ozone destruction, that, depending on plume dispersal, can be maintained for several days. The very high concentrations of sulfur dioxide in the volcanic plume reduces the lifetime of the OH radical drastically, so that it is virtually absent in the volcanic plume. This would imply an increased lifetime of methane in volcanic plumes, unless reactive chlorine chemistry in the plume is strong enough to offset the lack of OH chemistry. A further effect of bromine chemistry in addition to ozone destruction shown by the model studies presented here, is the oxidation of mercury. This relates to mercury that has been coemitted with bromine from the volcano but also to background atmospheric mercury. The rapid oxidation of mercury implies a drastically reduced atmospheric lifetime of mercury so that the contribution of volcanic mercury to the atmospheric background might be less than previously thought. However, the implications, especially health and environmental effects due to deposition, might be substantial and warrant further studies, especially field measurements to test this hypothesis.

  5. Orion Service Module Reaction Control System Plume Impingement Analysis Using PLIMP/RAMP2

    Science.gov (United States)

    Wang, Xiao-Yen; Lumpkin, Forrest E., III; Gati, Frank; Yuko, James R.; Motil, Brian J.

    2009-01-01

    The Orion Crew Exploration Vehicle Service Module Reaction Control System engine plume impingement was computed using the plume impingement program (PLIMP). PLIMP uses the plume solution from RAMP2, which is the refined version of the reacting and multiphase program (RAMP) code. The heating rate and pressure (force and moment) on surfaces or components of the Service Module were computed. The RAMP2 solution of the flow field inside the engine and the plume was compared with those computed using GASP, a computational fluid dynamics code, showing reasonable agreement. The computed heating rate and pressure using PLIMP were compared with the Reaction Control System plume model (RPM) solution and the plume impingement dynamics (PIDYN) solution. RPM uses the GASP-based plume solution, whereas PIDYN uses the SCARF plume solution. Three sets of the heating rate and pressure solutions agree well. Further thermal analysis on the avionic ring of the Service Module was performed using MSC Patran/Pthermal. The obtained temperature results showed that thermal protection is necessary because of significant heating from the plume.

  6. The Green Propellant Infusion Mission Thruster Performance Testing for Plume Diagnostics

    Science.gov (United States)

    Deans, Matthew C.; Reed, Brian D.; Arrington, Lynn A.; Williams, George J.; Kojima, Jun J.; Kinzbach, McKenzie I.; McLean, Christopher H.

    2014-01-01

    The Green Propellant Infusion Mission (GPIM) is sponsored by NASA's Space Technology Mission Directorate (STMD) Technology Demonstration Mission (TDM) office. The goal of GPIM is to advance the technology readiness level of a green propulsion system, specifically, one using the monopropellant, AF-M315E, by demonstrating ground handling, spacecraft processing, and on-orbit operations. One of the risks identified for GPIM is potential contamination of sensitive spacecraft surfaces from the effluents in the plumes of AF-M315E thrusters. NASA Glenn Research Center (GRC) is conducting activities to characterize the effects of AF-M315E plume impingement and deposition. GRC has established individual plume models of the 22-N and 1-N thrusters that will be used on the GPIM spacecraft. The model simulations will be correlated with plume measurement data from Laboratory and Engineering Model 22-N, AF-M315E thrusters. The thrusters are currently being tested in a small rocket, altitude facility at NASA GRC. A suite of diagnostics, including Raman spectroscopy, Rayleigh spectroscopy, and Schlieren imaging are being used to acquire plume measurements of AF-M315E thrusters. Plume data will include temperature, velocity, relative density, and species concentration. The plume measurement data will be compared to the corresponding simulations of the plume model. The GRC effort will establish a data set of AF-M315E plume measurements and a plume model that can be used for future AF-M315E applications.

  7. Mapping ocean outfall plumes and their mixing using autonomous underwater vehicles

    Science.gov (United States)

    Rogowski, Peter; Terrill, Eric; Otero, Mark; Hazard, Lisa; Middleton, William

    2012-07-01

    This paper reports on developing autonomous underwater vehicle (AUV) survey methods for ocean outfall discharge plumes and new insights gained on plume mixing. Unique to the study is mapping the discharge mixing using colored dissolved organic matter (CDOM) calibrated for effluent dilution. AUV mission planning methodologies for discharge plume sampling, plume characterization using onboard temperature, salinity and optical sensors, and comparison of observational data to model results are presented for the Point Loma Ocean Outfall offshore of San Diego, CA. The results are expected to be applicable to the general theme of mixing of submerged buoyant discharges. In the near-field, the plume is found to mix to a height consistent with the predictions of buoyant jet engineering models. At the far-field, the fine spatial scales of the plume resolved by the vehicle suggests that shear instabilities caused by internal waves can enhance plume mixing and elevate the discharge plume above the predicted equilibrium rise height. These results suggest that even under variable oceanic conditions, properly planned missions for AUVs equipped with an optical CDOM sensor in addition to traditional physical oceanographic sensors, can accurately map the mixing of ocean outfall plumes at resolutions not possible with traditional boat-based techniques. Variations of oceanic conditions are found to influence the mixing and fate of the plume at time scales generally not considered in the design of these discharges.

  8. Bipropellant rocket exhaust plume analysis on the Galileo spacecraft

    Science.gov (United States)

    Guernsey, C. S.; Mcgregor, R. D.

    1986-01-01

    This paper describes efforts to quantify the contaminant flow field produced by 10 N thrust bipropellant rocket engines used on the Galileo spacecraft. The prediction of the composition of the rocket exhaust by conventional techniques is found to be inadequate to explain experimental observations of contaminant deposition on moderately cold (200 K) surfaces. It is hypothesized that low volatility contaminants are formed by chemical reactions which occur on the surfaces. The flow field calculations performed using the direct simulation Monte Carlo method give the expected result that the use of line-of-sight plume shields may have very little effect on the flux of vapor phase contaminant species to a surface, especially if the plume shields are located so close to the engine that the interaction of the plume with the shield is in the transition flow regime. It is shown that significant variations in the exhaust plume composition caused by nonequilibrium effects in the flow field lead to very low concentrations of species which have high molecular weights in the more rarefied regions of the flow field. Recommendations for the design of spacecraft plume shields and further work are made.

  9. 双机并联氢氧火箭发动机尾焰流场特性三维数值仿真研究%Three-dimensional Numerical Simulation of Couple LOX/LH2Engine Plume Characteristics in Parallel-running

    Institute of Scientific and Technical Information of China (English)

    乔野; 聂万胜; 吴高杨; 冯伟; 丰松江

    2015-01-01

    以氢氧火箭发动机为模型,采用耦合可实现k-ε湍流模型的N-S方程,对发动机在地面发射阶段双机并联工作状态下的尾焰流场进行数值仿真研究,得到尾焰流场的各项参数分布及其变化规律,与理论分析结果对比,证明了算法的有效性和正确性,为开展多台发动机并联工作下尾焰的撞击和辐射特性等研究奠定了基础.%This passage is modeled with LOX/LH2 rocket engine, and uses the N-S equation coupled with realizablek-ε model to conduct numerical simulation research on the rocket plume flow field in the two-generator parallel-running station during the launch. The distribution and change rules of different parameters in the plume field have been gained. With the compare between the simulation data and the theoretical result, the algorithm is proved to be effective and correct. With that, a great foundation will be laid for the study of the plume impact and radiation in multi-generator parallel-running.

  10. Chemosensitive nanocomposite for conductometric detection of hydrazine and NADH

    Energy Technology Data Exchange (ETDEWEB)

    Lange, Ulrich [Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, 93047 Regensburg (Germany); Mirsky, Vladimir M., E-mail: vmirsky@hs-lausitz.d [Department of Nanobiotechnology, Lausitz University of Applied Sciences, 01968 Senftenberg (Germany)

    2011-04-01

    A new chemosensitive material based on palladium nanoparticles and PEDOT-PSS is described. The composite was characterized by transmission electron microscopy, cyclic voltammetry and in situ resistance measurements. The material was applied for conductometric detection of hydrazine and NADH. Upon exposure to these analytes PEDOT is reduced leading to an increase in its conductance. This process is catalyzed by palladium. A model for description of the potential dependence of polymer conductivity was suggested, tested and applied for the development of new calibration procedure of chemiresistors based on electroactive polymers.

  11. Performance of a capillary propellant management device with hydrazine

    Science.gov (United States)

    Tegart, J. R.

    1979-01-01

    The propellant management device that was successfully used in the Viking Orbiter spacecraft was selected for the main propulsion system of the Teleoperator Retrieval System (TRS). Due to differences in the missions and different propellants, the operation of this sheet metal vane device required reverification for the TRS application. An analytical investigation was performed considering the adverse acceleration environment and the high contract angle of the hydrazine propellant. Drop tower tests demonstrated that the device would provide propellant acquisition while the TRS was docked with Skylab, but its operation would have to be supplemented through propellant settling when free-flying.

  12. 60-WATT HYDRAZINE-AIR FUEL CELL SYSTEM.

    Science.gov (United States)

    fuel cell system as presented in our Design Plan. Prior to preparation of the Design Plan, a systems analysis of the basic electrochemical system was made. From the results of this analysis, the operating parameters of the support equipment were defined and an initial selection of components made. System components defined were: the cell stack, electrolyte tank, hydrazine feed system, cooling and chemical air blowers, voltage regulator, and thermal control system. A package design was then made for these components and the final detail design completed.

  13. A rhodol-based fluorescent chemosensor for hydrazine and its application in live cell bioimaging

    Science.gov (United States)

    Tiensomjitr, Khomsan; Noorat, Rattha; Wechakorn, Kanokorn; Prabpai, Samran; Suksen, Kanoknetr; Kanjanasirirat, Phongthon; Pewkliang, Yongyut; Borwornpinyo, Suparerk; Kongsaeree, Palangpon

    2017-10-01

    A rhodol cinnamate fluorescent chemosensor (RC) has been developed for selective detection of hydrazine (N2H4). In aqueous medium, the rhodol-based probe exhibited high selectivity for hydrazine among other molecules. The addition of hydrazine triggered a fluorescence emission with 48-fold enhancement based on hydrazinolysis and a subsequent ring-opening process. The chemical probe also displayed a selective colorimetric response toward N2H4 from colorless solution to pink, readily observed by the naked eye. The detection limit of RC for hydrazine was calculated to be 300 nM (9.6 ppb). RC is membrane permeable and was successfully demonstrated to detect hydrazine in live HepG2 cells by confocal fluorescence microscopy.

  14. Biogeochemistry of landfill leachate plumes

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Kjeldsen, Peter; Bjerg, Poul Løgstrup

    2001-01-01

    is on dissolved organic matter, xenobiotic organic compounds, inorganic macrocomponents as anions and cations, and heavy metals. Laboratory as well as field investigations are included. This review is an up-date of an earlier comprehensive review. The review shows that most leachate contamination plumes...... the behavior of the contaminants in the plume as the leachate migrates away from the landfill. Diverse microbial communities have been identified in leachate plumes and are believed to be responsible for the redox processes. Dissolved organic C in the leachate, although it appears to be only slowly degradable...

  15. Predicting Engine Parameters using the Optical Spectrum

    Data.gov (United States)

    National Aeronautics and Space Administration — The Optical Plume Anomaly Detection (OPAD) system is under development to predict engine anomalies and engine parameters of the Space Shuttle's Main Engine (SSME)....

  16. Reusable rocket engine optical condition monitoring

    Science.gov (United States)

    Wyett, L.; Maram, J.; Barkhoudarian, S.; Reinert, J.

    1987-01-01

    Plume emission spectrometry and optical leak detection are described as two new applications of optical techniques to reusable rocket engine condition monitoring. Plume spectrometry has been used with laboratory flames and reusable rocket engines to characterize both the nominal combustion spectra and anomalous spectra of contaminants burning in these plumes. Holographic interferometry has been used to identify leaks and quantify leak rates from reusable rocket engine joints and welds.

  17. Dihydropyrimidine based hydrazine dihydrochloride derivatives as potent urease inhibitors.

    Science.gov (United States)

    Khan, Ajmal; Hashim, Jamshed; Arshad, Nuzhat; Khan, Ijaz; Siddiqui, Naureen; Wadood, Abdul; Ali, Muzaffar; Arshad, Fiza; Khan, Khalid Mohammed; Choudhary, M Iqbal

    2016-02-01

    Four series of heterocyclic compounds 4-dihydropyrimidine-2-thiones 7-12 (series A), N,S-dimethyl-dihydropyrimidines 13-18 (series B), hydrazine derivatives of dihydropyrimidine 19-24 (series C), and tetrazolo dihydropyrimidine derivatives 25-30 (series D), were synthesized and evaluated for in vitro urease inhibitory activity. The series B-D were first time examined for urease inhibition. Series A and C were found to be significantly active with IC50 values between 34.7-42.9 and 15.0-26.0 μM, respectively. The structure-activity relationship showed that the free S atom and hydrazine moiety are the key pharmacophores against urease enzyme. The kinetic studies of the active series A (7-12) and C (19-24) were carried out to determine their modes of inhibition and dissociation constants Ki. Compounds of series A (7-12) and series C (19-24) showed a mixed-type of inhibition with Ki values ranging between 15.76-25.66 and 14.63-29.42 μM, respectively. The molecular docking results showed that all the active compounds of both series have significant binding interactions with the active sites specially Ni-ion of the urease enzyme. Cytotoxicity of all series A-D was also evaluated against mammalian mouse fibroblast 3T3 cell lines, and no toxicity was observed in cellular model.

  18. Complexes with Mercaptosuccinic Acid and Hydrazine as Ligands

    Directory of Open Access Journals (Sweden)

    S. Devipriya

    2013-01-01

    Full Text Available Reaction of hydrazine and mercaptosuccinic acid with metal ions forms\tcomplexes with general formula [Ln(N2H42CH2(COOCH(SH(COO1.5]·(H2O, where Ln = La(III, Pr(III, Nd(III, Sm(III, and Gd(III at pH 5. The complexes have been characterized by elemental analysis, IR and UV-visible spectroscopic, thermal and X-ray diffraction studies. The IR data reveal that the acid moiety in the complexes is present as dianion due to the deprotonation of COOH groups by lanthanides in these complexes, leaving –SH group unionized and hydrazine as bidental neutral ligand showing absorptions in the range of 945–948 cm−1. The thermoanalytical data evince that the complexes are stable up to 103°C and undergo complete decomposition in the range of 550–594°C resulting in metal oxides. SEM images of La2O3 and Gd2O3 residues show their nano sized clusters suggesting that the complexes may be used as precursors for nano La2O3 and Gd2O3, respectively. X-ray powder diffraction patterns show isomorphism among the complexes. The kinetic parameters of the decomposition of the complexes have been computed by Coats-Redfern equation.

  19. Smoke plumes: Emissions and effects

    Science.gov (United States)

    Susan O' Neill; Shawn Urbanski; Scott Goodrick; Sim Larkin

    2017-01-01

    Smoke can manifest itself as a towering plume rising against the clear blue sky-or as a vast swath of thick haze, with fingers that settle into valleys overnight. It comes in many forms and colors, from fluffy and white to thick and black. Smoke plumes can rise high into the atmosphere and travel great distances across oceans and continents. Or smoke can remain close...

  20. An Assessment of Hydrazine, Hydrazine Hydrate and Liquid Ammonia as Fuels for Rocket Propulsion

    Science.gov (United States)

    1949-08-01

    problems. Finally it should be mentioned that the Acre jet Engineering Corporation (33) have found that in solutions of Li in liq.i the metal amido is...also be stressed that the stability of the solutions of those borohydrides in NH3 and N2H4 does not seem to have been investigated. A summary of the

  1. Equatorial spread F fossil plumes

    Directory of Open Access Journals (Sweden)

    S. L. Ossakow

    2010-11-01

    Full Text Available Behaviour of equatorial spread F (ESF fossil plumes, i.e., ESF plumes that have stopped rising, is examined using the NRL SAMI3/ESF three-dimensional simulation code. We find that fossil bubbles, plasma density depletions associated with fossil plumes, can persist as high-altitude equatorial depletions even while being "blown" by zonal winds. Corresponding airglow-proxy images of fossil plumes, plots of electron density versus longitude and latitude at a constant altitude of 288 km, are shown to partially "fill in" in most cases, beginning with the highest altitude field lines within the plume. Specifically, field lines upon which the E field has fallen entirely to zero are affected and only the low altitude (≤600 km portion if each field line fills in. This suggests that it should be possible to observe a bubble at high altitude on a field line for which the corresponding airglow image no longer shows a depletion. In all cases ESF plumes stop rising when the flux-tube-integrated ion mass density inside the upper edge of the bubble is equal to that of the nearby background, further supporting the result of Krall et al. (2010b.

  2. Test and analysis of the infrared characteristic of the plume-smoke

    Science.gov (United States)

    Zhang, Xiaolong; Zhang, Guang; Chen, Dapeng; Dong, Yanbing

    2015-04-01

    The plume-smoke is one of the main infrared characteristic signal sources of the engine. In this paper, the infrared signal characteristic of a small test engine's plume-smoke is studied. We conduct a quantitative observation of some specific points in the movement path of the plume-smoke by the MW and LW infrared thermal imager. Through the analysis of the smokeless and smoke infrared sequential images, we can get the infrared radiation and the transmission characteristics of the plume-smoke and their variation law with time. Experiments show that there exists a critical temperature of the plume-smoke; the radiation of background can increase when the temperature of the plume-smoke is higher than the critical temperature. On the contrary, the radiation of background decreases when the temperature of the plume-smoke is lower than the critical temperature. In this paper, the research provides a reference for further study on the infrared characteristic of the plume-smoke.

  3. Antisymmetric Amino-Wagging Band of Hydrazine up to K' = 13 Levels

    Science.gov (United States)

    Gulaczyk; Kr; Valentin

    1997-12-01

    A newly recorded high-resolution infrared spectrum of hydrazine has been studied in the 729-1198 cm-1 region (the nu12 antisymmetric wagging band) with a resolution of 0.002 cm-1. About 1350 transitions with K' from 7 to 13 have been newly assigned and about 2350 transitions with lower values of K' reanalyzed with the improved precision. The effective parameters have been calculated separately for each value of K' using the Hougen-Ohashi hamiltonian for hydrazine. The extended assignment completes the analysis of the nu12 band of hydrazine. Copyright 1997 Academic Press. Copyright 1997Academic Press

  4. Linear Spectral Analysis of Plume Emissions Using an Optical Matrix Processor

    Science.gov (United States)

    Gary, C. K.

    1992-01-01

    Plume spectrometry provides a means to monitor the health of a burning rocket engine, and optical matrix processors provide a means to analyze the plume spectra in real time. By observing the spectrum of the exhaust plume of a rocket engine, researchers have detected anomalous behavior of the engine and have even determined the failure of some equipment before it would normally have been noticed. The spectrum of the plume is analyzed by isolating information in the spectrum about the various materials present to estimate what materials are being burned in the engine. Scientists at the Marshall Space Flight Center (MSFC) have implemented a high resolution spectrometer to discriminate the spectral peaks of the many species present in the plume. Researchers at the Stennis Space Center Demonstration Testbed Facility (DTF) have implemented a high resolution spectrometer observing a 1200-lb. thrust engine. At this facility, known concentrations of contaminants can be introduced into the burn, allowing for the confirmation of diagnostic algorithms. While the high resolution of the measured spectra has allowed greatly increased insight into the functioning of the engine, the large data flows generated limit the ability to perform real-time processing. The use of an optical matrix processor and the linear analysis technique described below may allow for the detailed real-time analysis of the engine's health. A small optical matrix processor can perform the required mathematical analysis both quicker and with less energy than a large electronic computer dedicated to the same spectral analysis routine.

  5. ASRM radiation and flowfield prediction status. [Advanced Solid Rocket Motor plume radiation prediction

    Science.gov (United States)

    Reardon, J. E.; Everson, J.; Smith, S. D.; Sulyma, P. R.

    1991-01-01

    Existing and proposed methods for the prediction of plume radiation are discussed in terms of their application to the NASA Advanced Solid Rocket Motor (ASRM) and Space Shuttle Main Engine (SSME) projects. Extrapolations of the Solid Rocket Motor (SRM) are discussed with respect to preliminary predictions of the primary and secondary radiation environments. The methodology for radiation and initial plume property predictions are set forth, including a new code for scattering media and independent secondary source models based on flight data. The Monte Carlo code employs a reverse-evaluation approach which traces rays back to their point of absorption in the plume. The SRM sea-level plume model is modified to account for the increased radiation in the ASRM plume due to the ASRM's propellant chemistry. The ASRM cycle-1 environment predictions are shown to identify a potential reason for the shutdown spike identified with pre-SRM staging.

  6. Stoichiometry and kinetics of the anaerobic ammonium oxidation (Anammox) with trace hydrazine addition.

    Science.gov (United States)

    Yao, Zongbao; Lu, Peili; Zhang, Daijun; Wan, Xinyu; Li, Yulian; Peng, Shuchan

    2015-12-01

    Purpose of this study is to investigate the stoichiometry and kinetics of anaerobic ammonium oxidation (Anammox) with trace hydrazine addition. The stoichiometry was established based on the electron balance of Anammox process with trace N2H4 addition. The stoichiometric coefficients were determined by the proton consumption and the changes in substrates and products. It was found that trace N2H4 addition can increase the yield of Anammox bacteria (AnAOB) and reduce NO3(-) yield, which enhances the Anammox. Subsequently, kinetic model of Anammox with trace N2H4 addition was developed, and the parameters of the anaerobic degradation model of N2H4 were obtained for the first time. The maximum specific substrate utilization rate, half-saturation constant and inhibition constant of N2H4 were 25.09mgN/g VSS/d, 10.42mgN/L and 1393.88mgN/L, respectively. These kinetic parameters might provide important information for the engineering applications of Anammox with trace N2H4 addition.

  7. Remediation of Cr(VI)-Contaminated Soil Using the Acidified Hydrazine Hydrate.

    Science.gov (United States)

    Ma, Yameng; Li, Fangfang; Jiang, Yuling; Yang, Weihua; Lv, Lv; Xue, Haotian; Wang, Yangyang

    2016-09-01

    Acidified hydrazine hydrate was used to remediate Cr(VI)-contaminated soil. The content of water-soluble Cr(VI) in contaminated soil was 4977.53 mg/kg. The optimal initial pH of hydrazine hydrate solution, soil to solution ratio and molar ratio of Cr(VI) to hydrazine hydrate for remediation of Cr(VI)-contaminated soil were 5.0, 3:1 and 1:3, respectively. Over 99.50 % of water-soluble Cr(VI) in the contaminated soil was reduced at the optimal condition within 30 min. The remediated soil can keep stable within 4 months. Meanwhile the total phosphorus increased from 0.47 to 4.29 g/kg, indicating that using of acidified hydrazine hydrate is an effective method to remediate Cr(VI)-contaminated soil.

  8. Au(I)-Catalyzted Synthesis of 5-Bromodifluoromethyl Pyrazoles from Fluorinated Alkynyl Ketones and Hydrazine

    Institute of Scientific and Technical Information of China (English)

    李珊; 李正珂; 彭东杰; 李亚军; 祝江涛; 解海波; 袁雅芬; 陈资衔; 吴永明

    2011-01-01

    Fluorinated alkynyl ketones react with hydrazine to give fluorinated pyrazols in good to excellent yields with Au(I) as catalyst. All the reactions were carried out at room temperature with excellent regioselectivity.

  9. Fixation and loss of hydrazine-induced premutational damage in Haemophilus influenzae

    Energy Technology Data Exchange (ETDEWEB)

    Kimball, R.F.; Hirsch, B.F.

    1976-01-01

    Premutational damage induced in Haemophilus influenzae by hydrazine appears to be fixed as final mutation only at replication as judged by the transformation assay. Fixation at replication is independent of the rec 1 gene, unlike the case with nitrosocarbaryl. Prior to replication premutational damage induced by hydrazine disappears by an unknown process that is not dependent on the presence of a pyrimidine dimer excision system nor on the rec 1 gene. Hydrazine does not produce detectable single-strand breaks or alkali-labile sites in the treated DNA nor gaps in DNA newly synthesized after treatment. In these respects it also differs from nitroso compounds. It is concluded that hydrazine acts to produce an altered base, possibly N(4)-aminocytosine, that produces mutations by mispairing at replication rather than by error-prone repair.

  10. Plumes in stellar convection zones

    CERN Document Server

    Zahn, J P

    1999-01-01

    All numerical simulations of compressible convection reveal the presence of strong downwards directed flows. Thanks to helioseismology, such plumes have now been detected also at the top of the solar convection zone, on super- granular scales. Their properties may be crudely described by adopting Taylor's turbulent entrainment hypothesis, whose validity is well established under various conditions. Using this model, one finds that the strong density stratification does not prevent the plumes from traversing the whole convection zone, and that they carry upwards a net energy flux (Rieutord & Zahn 1995). They penetrate to some extent in the adjacent stable region, where they establish a nearly adiabatic stratification. These plumes have a strong impact on the dynamics of stellar convection zones, and they play probably a key role in the dynamo mechanism.

  11. U.S. experience with hydrazine and flow-accelerated corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Merilo, M.; Munson, D.; Horowitz, J.S. [EPRI US (United States); Bouchacourt, M. [EDF France (France)

    2002-07-01

    Flow-accelerated corrosion (FAC) has been studied intensely for the last 30 years. In most regards, the parametric behavior of FAC has been well understood since the eighties. However, recent experience showing the impact of hydrazine has challenged this understanding. Until the early 1990's, hydrazine levels at most U.S. PWRs had been low, typically around 20 ppb. Since the mid 1990's the U.S. trend has been to increase hydrazine concentration (> 100 ppb) to provide further protection the steam generators tubes from stress corrosion cracking. In the last five years, high concentrations of hydrazine have been shown in the laboratory to affect the rate of FAC. These experiments have demonstrated this effect although there remains considerable scatter in the data supporting this conclusion. It is believed that the impact of hydrazine is due to the change in the oxidizing-reducing potential of the solution, but there is no generally accepted theory to completely describe its behavior. Recently, plant experience has begun to support the laboratory data that high hydrazine does increase the rate of FAC. It should be noted that there are several factors affecting the rate of FAC. Since most plants have changed their water chemistry in recent years, it has been difficult to ''back-out'' the influence of hydrazine. But now, plant experience has clearly shown the impact of high hydrazine especially in the high temperature portions of the feedwater piping. This has been seen at two PWRs, discussed below, and perhaps at several others. This accelerated thinning of the feedwater piping is especially significant since feedwater piping is particularly expensive to inspect and to replace. In addition to the experience with piping, there has also been degradation reported in steam generators, particularly at Gravelines in France, possibly linked to high hydrazine. In order to deal with this issue, the EPRI computer program CHECWORKS was modified in

  12. Coastal river plumes: Collisions and coalescence

    Science.gov (United States)

    Warrick, Jonathan A.; Farnsworth, Katherine L.

    2017-02-01

    Plumes of buoyant river water spread in the ocean from river mouths, and these plumes influence water quality, sediment dispersal, primary productivity, and circulation along the world's coasts. Most investigations of river plumes have focused on large rivers in a coastal region, for which the physical spreading of the plume is assumed to be independent from the influence of other buoyant plumes. Here we provide new understanding of the spreading patterns of multiple plumes interacting along simplified coastal settings by investigating: (i) the relative likelihood of plume-to-plume interactions at different settings using geophysical scaling, (ii) the diversity of plume frontal collision types and the effects of these collisions on spreading patterns of plume waters using a two-dimensional hydrodynamic model, and (iii) the fundamental differences in plume spreading patterns between coasts with single and multiple rivers using a three-dimensional hydrodynamic model. Geophysical scaling suggests that coastal margins with numerous small rivers (watershed areas 100,000 km2). When two plume fronts meet, several types of collision attributes were found, including refection, subduction and occlusion. We found that the relative differences in pre-collision plume densities and thicknesses strongly influenced the resulting collision types. The three-dimensional spreading of buoyant plumes was found to be influenced by the presence of additional rivers for all modeled scenarios, including those with and without Coriolis and wind. Combined, these results suggest that plume-to-plume interactions are common phenomena for coastal regions offshore of the world's smaller rivers and for coastal settings with multiple river mouths in close proximity, and that the spreading and fate of river waters in these settings will be strongly influenced by these interactions. We conclude that new investigations are needed to characterize how plumes interact offshore of river mouths to better

  13. Coastal river plumes: Collisions and coalescence

    Science.gov (United States)

    Warrick, Jonathan; Farnsworth, Katherine L

    2017-01-01

    Plumes of buoyant river water spread in the ocean from river mouths, and these plumes influence water quality, sediment dispersal, primary productivity, and circulation along the world’s coasts. Most investigations of river plumes have focused on large rivers in a coastal region, for which the physical spreading of the plume is assumed to be independent from the influence of other buoyant plumes. Here we provide new understanding of the spreading patterns of multiple plumes interacting along simplified coastal settings by investigating: (i) the relative likelihood of plume-to-plume interactions at different settings using geophysical scaling, (ii) the diversity of plume frontal collision types and the effects of these collisions on spreading patterns of plume waters using a two-dimensional hydrodynamic model, and (iii) the fundamental differences in plume spreading patterns between coasts with single and multiple rivers using a three-dimensional hydrodynamic model. Geophysical scaling suggests that coastal margins with numerous small rivers (watershed areas  100,000 km2). When two plume fronts meet, several types of collision attributes were found, including refection, subduction and occlusion. We found that the relative differences in pre-collision plume densities and thicknesses strongly influenced the resulting collision types. The three-dimensional spreading of buoyant plumes was found to be influenced by the presence of additional rivers for all modeled scenarios, including those with and without Coriolis and wind. Combined, these results suggest that plume-to-plume interactions are common phenomena for coastal regions offshore of the world’s smaller rivers and for coastal settings with multiple river mouths in close proximity, and that the spreading and fate of river waters in these settings will be strongly influenced by these interactions. We conclude that new investigations are needed to characterize how plumes interact offshore of river mouths to

  14. Overview of NASA GRCs Green Propellant Infusion Mission Thruster Testing and Plume Diagnostics

    Science.gov (United States)

    Deans, Matthew C.; Reed, Brian D.; Yim, John T.; Arrington, Lynn A.; Williams, George J.; Kojima, Jun J.; McLean, Christopher H.

    2014-01-01

    The Green Propellant Infusion Mission (GPIM) is sponsored by NASA's Space Technology Mission Directorate (STMD) Technology Demonstration Mission (TDM) office. The goal of GPIM is to advance the technology readiness level of a green propulsion system, specifically, one using the monopropellant, AF-M315E, by demonstrating ground handling, spacecraft processing, and on-orbit operations. One of the risks identified for GPIM is potential contamination of sensitive spacecraft surfaces from the effluents in the plumes of AF-M315E thrusters. NASA Glenn Research Center (GRC) is conducting activities to characterize the effects of AF-M315E plume impingement and deposition. GRC has established individual plume models of the 22-N and 1-N thrusters that will be used on the GPIM spacecraft. The models describe the pressure, temperature, density, Mach number, and species concentration of the AF-M315E thruster exhaust plumes. The models are being used to assess the impingement effects of the AF-M315E thrusters on the GPIM spacecraft. The model simulations will be correlated with plume measurement data from Laboratory and Engineering Model 22-N, AF-M315E thrusters. The thrusters will be tested in a small rocket, altitude facility at NASA GRC. The GRC thruster testing will be conducted at duty cycles representatives of the planned GPIM maneuvers. A suite of laser-based diagnostics, including Raman spectroscopy, Rayleigh spectroscopy, Schlieren imaging, and physical probes will be used to acquire plume measurements of AFM315E thrusters. Plume data will include temperature, velocity, relative density, and species concentration. The plume measurement data will be compared to the corresponding simulations of the plume model. The GRC effort will establish a data set of AF-M315E plume measurements and a plume model that can be used for future AF-M315E applications.

  15. Propellant Grade Hydrazine in Mono/Bi-propellant Thrusters: Preparation and Performance Evaluation

    Directory of Open Access Journals (Sweden)

    S. Krishnamachary

    2015-03-01

    Full Text Available Propellant grade hydrazine was prepared with 64 per cent yield and 95.5 per cent purity. Purity of the propellant grade hydrazine was determined using wet chemical, gas chromatographic (GC and eudiometric methods. It was observed that the compositions containing blends of hydrazine-methyl alcohol-ammonium nitrate and hydrazine-methyl alcohol-ammonium perchlorate were not found to be frozen even after cooling to -65 °C for 30 minutes. Mono and bi-propellant thrusters were designed and developed to demonstrate the performance of prepared propellant grade hydrazine as a promising rocket fuel. Five static tests with 22 N thruster and one static test with 1 N thruster were performed successfully in mono-propellant mode. The hurdles of chamber pressure oscillations were overcome by compact packing of the catalyst. The desired decomposition and chamber pressure were achieved. One static test was performed successfully with 60 N bi-propellant thruster. The desired chamber pressure and thrust were achieved. The combustion was smooth and C* achieved was higher than that of UH-25, N2O4 combination. The performance of prepared propellant grade hydrazine shows it as a promising rocket fuels.Defence Science Journal, Vol. 65, No. 1, January 2015, pp.31-38, DOI:http://dx.doi.org/10.14429/dsj.65.7986

  16. Hydrazine selective dual signaling chemodosimetric probe in physiological conditions and its application in live cells

    Energy Technology Data Exchange (ETDEWEB)

    Nandi, Sandip; Sahana, Animesh; Mandal, Sandip [Department of Chemistry, The University of Burdwan, Burdwan, 713104 West Bengal (India); Sengupta, Archya; Chatterjee, Ansuman [Department of Zoology, Visva Bharati University, Santiniketan, West Bengal (India); Safin, Damir A., E-mail: damir.a.safin@gmail.com [Institute of Condensed Matter and Nanosciences, Molecules, Solids and Reactivity (IMCN/MOST), Université catholique de Louvain, Place L. Pasteur 1, 1348 Louvain-la-Neuve (Belgium); Babashkina, Maria G.; Tumanov, Nikolay A.; Filinchuk, Yaroslav [Institute of Condensed Matter and Nanosciences, Molecules, Solids and Reactivity (IMCN/MOST), Université catholique de Louvain, Place L. Pasteur 1, 1348 Louvain-la-Neuve (Belgium); Das, Debasis, E-mail: ddas100in@yahoo.com [Department of Chemistry, The University of Burdwan, Burdwan, 713104 West Bengal (India)

    2015-09-17

    A rhodamine–cyanobenzene conjugate, (E)-4-((2-(3′,6′-bis(diethylamino)-3-oxospiro[isoindoline-1,9′-xanthene] -2-yl)ethylimino)methyl)benzonitrile (1), which structure has been elucidated by single crystal X-ray diffraction, was synthesized for selective fluorescent “turn-on” and colorimetric recognition of hydrazine at physiological pH 7.4. It was established that 1 detects hydrazine up to 58 nM. The probe is useful for the detection of intracellular hydrazine in the human breast cancer cells MCF-7 using a fluorescence microscope. Spirolactam ring opening of 1, followed by its hydrolysis, was established as a probable mechanism for the selective sensing of hydrazine. - Highlights: • A selective rhodamine–cyanobenzene conjugate is synthesized. • The conjugate is a selective dual signaling chemodosimetric probe towards hydrazine. • Spirolactam ring opening of the probe, followed by its hydrolysis, is the sensing mechanism. • The probe detects hydrazine in the human breast cancer cells MCF-7 imaging.

  17. Preparation of hydrazine functionalized polymer brushes hybrid magnetic nanoparticles for highly specific enrichment of glycopeptides.

    Science.gov (United States)

    Huang, Guang; Sun, Zhen; Qin, Hongqiang; Zhao, Liang; Xiong, Zhichao; Peng, Xiaojun; Ou, Junjie; Zou, Hanfa

    2014-05-07

    Hydrazide chemistry is a powerful technique in glycopeptides enrichment. However, the low density of the monolayer hydrazine groups on the conventional hydrazine-functionalized magnetic nanoparticles limits the efficiency of glycopeptides enrichment. Herein, a novel magnetic nanoparticle grafted with poly(glycidyl methacrylate) (GMA) brushes was fabricated via reversible addition-fragmentation chain transfer (RAFT) polymerization, and a large amount of hydrazine groups were further introduced to the GMA brushes by ring-opening the epoxy groups with hydrazine hydrate. The resulting magnetic nanoparticles (denoted as Fe3O4@SiO2@GMA-NHNH2) demonstrated the high specificity of capturing glycopeptides from a tryptic digest of the sample comprising a standard non-glycosylated protein bovine serum albumin (BSA) and four standard glycoproteins with a weight ratio of 50 : 1, and the detection limit was as low as 130 fmol. In the analysis of a real complex biological sample, the tryptic digest of hepatocellular carcinoma, 179 glycosites were identified by the Fe3O4@SiO2@GMA-NHNH2 nanoparticles, surpassing that of 68 glycosites by Fe3O4@SiO2-single-NHNH2 (with monolayer hydrazine groups on the surface). It can be expected that the magnetic nanoparticles modified with hydrazine functionalized polymer brushes via RAFT technique will improve the specificity and the binding capacity of glycopeptides from complex samples, and show great potential in the analysis of protein glycosylation in biological samples.

  18. Enceladus Plume Density Modeling and Reconstruction for Cassini Attitude Control System

    Science.gov (United States)

    Sarani, Siamak

    2010-01-01

    In 2005, Cassini detected jets composed mostly of water, spouting from a set of nearly parallel rifts in the crust of Enceladus, an icy moon of Saturn. During an Enceladus flyby, either reaction wheels or attitude control thrusters on the Cassini spacecraft are used to overcome the external torque imparted on Cassini due to Enceladus plume or jets, as well as to slew the spacecraft in order to meet the pointing needs of the on-board science instruments. If the estimated imparted torque is larger than it can be controlled by the reaction wheel control system, thrusters are used to control the spacecraft. Having an engineering model that can predict and simulate the external torque imparted on Cassini spacecraft due to the plume density during all projected low-altitude Enceladus flybys is important. Equally important is being able to reconstruct the plume density after each flyby in order to calibrate the model. This paper describes an engineering model of the Enceladus plume density, as a function of the flyby altitude, developed for the Cassini Attitude and Articulation Control Subsystem, and novel methodologies that use guidance, navigation, and control data to estimate the external torque imparted on the spacecraft due to the Enceladus plume and jets. The plume density is determined accordingly. The methodologies described have already been used to reconstruct the plume density for three low-altitude Enceladus flybys of Cassini in 2008 and will continue to be used on all remaining low-altitude Enceladus flybys in Cassini's extended missions.

  19. Enceladus Plume Density Modeling and Reconstruction for Cassini Attitude Control System

    Science.gov (United States)

    Sarani, Siamak

    2010-01-01

    In 2005, Cassini detected jets composed mostly of water, spouting from a set of nearly parallel rifts in the crust of Enceladus, an icy moon of Saturn. During an Enceladus flyby, either reaction wheels or attitude control thrusters on the Cassini spacecraft are used to overcome the external torque imparted on Cassini due to Enceladus plume or jets, as well as to slew the spacecraft in order to meet the pointing needs of the on-board science instruments. If the estimated imparted torque is larger than it can be controlled by the reaction wheel control system, thrusters are used to control the spacecraft. Having an engineering model that can predict and simulate the external torque imparted on Cassini spacecraft due to the plume density during all projected low-altitude Enceladus flybys is important. Equally important is being able to reconstruct the plume density after each flyby in order to calibrate the model. This paper describes an engineering model of the Enceladus plume density, as a function of the flyby altitude, developed for the Cassini Attitude and Articulation Control Subsystem, and novel methodologies that use guidance, navigation, and control data to estimate the external torque imparted on the spacecraft due to the Enceladus plume and jets. The plume density is determined accordingly. The methodologies described have already been used to reconstruct the plume density for three low-altitude Enceladus flybys of Cassini in 2008 and will continue to be used on all remaining low-altitude Enceladus flybys in Cassini's extended missions.

  20. OPAD through 1991 - Status report no. 2. [Optical Plume Anomaly Detection

    Science.gov (United States)

    Powers, W. T.; Cooper, A. E.; Wallace, T. L.

    1991-01-01

    The Optical Plume Anomaly Detection (OPAD) experimental program has attempted to develop a rocket engine health monitor for the detection, and if possible the quantification, of anomalous atomic and molecular species in exhaust plumes. The test program has formulated instrument designs allowing both wide spectral range and high spectral resolution. Attention is presently given to OPAD data collected for the SSME at NASA-Marshall's technology test stand, with a view to spectral emissions at startup and variations in baseline plume emissions due to changes in rated power level.

  1. Flow field description of the Space Shuttle Vernier reaction control system exhaust plumes

    Science.gov (United States)

    Cerimele, Mary P.; Alred, John W.

    1987-01-01

    The flow field for the Vernier Reaction Control System (VRCS) jets of the Space Shuttle Orbiter has been calculated from the nozzle throat to the far-field region. The calculations involved the use of recently improved rocket engine nozzle/plume codes. The flow field is discussed, and a brief overview of the calculation techniques is presented. In addition, a proposed on-orbit plume measurement experiment, designed to improve future estimations of the Vernier flow field, is addressed.

  2. Lidar measurements of plume statistics

    DEFF Research Database (Denmark)

    Ejsing Jørgensen, Hans; Mikkelsen, T.

    1993-01-01

    the source, instantaneous crosswind plume profiles were detected repetitively at high spatial (1.5 m) and temporal (3 sec) intervals by use of a mini LIDAR system. The experiments were accompanied by measurement of the surface-layer mean wind and turbulence quantities by sonic anemometers. On the basis...

  3. Ship exhaust gas plume cooling

    NARCIS (Netherlands)

    Schleijpen, H.M.A.; Neele, P.P.

    2004-01-01

    The exhaust gas plume is an important and sometimes dominating contributor to the infrared signature of ships. Suppression of the infrared ship signatures has been studied by TNO for the Royal Netherlands Navy over considerable time. This study deals with the suppression effects, which can be achiev

  4. Downwelling wind, tides, and estuarine plume dynamics

    Science.gov (United States)

    Lai, Zhigang; Ma, Ronghua; Huang, Mingfen; Chen, Changsheng; Chen, Yong; Xie, Congbin; Beardsley, Robert C.

    2016-06-01

    The estuarine plume dynamics under a downwelling-favorable wind condition were examined in the windy dry season of the Pearl River Estuary (PRE) using the PRE primitive-equation Finite-Volume Community Ocean Model (FVCOM). The wind and tide-driven estuarine circulation had a significant influence on the plume dynamics on both local and remote scales. Specifically, the local effect of downwelling-favorable winds on the plume was similar to the theoretical descriptions of coastal plumes, narrowing the plume width, and setting up a vertically uniform downstream current at the plume edge. Tides tended to reduce these plume responses through local turbulent mixing and advection from upstream regions, resulting in an adjustment of the isohalines in the plume and a weakening of the vertically uniform downstream current. The remote effect of downwelling-favorable winds on the plume was due to the wind-induced estuarine sea surface height (SSH), which strengthened the estuarine circulation and enhanced the plume transport accordingly. Associated with these processes, tide-induced mixing tended to weaken the SSH gradient and thus the estuarine circulation over a remote influence scale. Overall, the typical features of downwelling-favorable wind-driven estuarine plumes revealed in this study enhanced our understanding of the estuarine plume dynamics under downwelling-favorable wind conditions.

  5. Characterization of redox conditions in pollution plumes

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Bjerg, Poul Løgstrup; Banwart, Steven A.

    2000-01-01

    Evalution of redox conditions in groundwater pollution plumes is often a prerequisite for understanding the behviour of the pollutants in the plume and for selecting remediation approaches. Measuring of redox conditions in pollution plumes is, however, a fairly recent issue and yet relative few...

  6. Characterization of redox conditions in pollution plumes

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Bjerg, Poul Løgstrup; Banwart, Steven A.

    2000-01-01

    Evalution of redox conditions in groundwater pollution plumes is often a prerequisite for understanding the behviour of the pollutants in the plume and for selecting remediation approaches. Measuring of redox conditions in pollution plumes is, however, a fairly recent issue and yet relative few...

  7. Hydrazine borane-induced destabilization of ammonia borane, and vice versa

    Energy Technology Data Exchange (ETDEWEB)

    Petit, Jean-Fabien; Moussa, Georges [IEM (Institut Europeen des Membranes), UMR 5635 (CNRS-ENSCM-UM2), Universite Montpellier 2, Place E. Bataillon, F-34095 Montpellier (France); Demirci, Umit B., E-mail: umit.demirci@um2.fr [IEM (Institut Europeen des Membranes), UMR 5635 (CNRS-ENSCM-UM2), Universite Montpellier 2, Place E. Bataillon, F-34095 Montpellier (France); Toche, François; Chiriac, Rodica [Université Lyon 1, CNRS, UMR 5615, Laboratoire des Multimatériaux et Interfaces, 43 boulevard du 11 Novembre 1918, F-69622 Villeurbanne (France); Miele, Philippe [IEM (Institut Europeen des Membranes), UMR 5635 (CNRS-ENSCM-UM2), Universite Montpellier 2, Place E. Bataillon, F-34095 Montpellier (France)

    2014-08-15

    Graphical abstract: - Highlights: • Hydrazine borane and ammoniaborane (mole ratio 1:1) destabilize each other. • This is characterized by a melting point at ∼30 °C and decomposition into hydrazine. • Also, some hydrogen H{sub 2} is “explosively” liberated at around 90 °C. • The mixture can be however stabilized into a potential hydrogen storage material. • This hydrogen storage material dehydrogenates up to 300 °C to form boron nitride. - Abstract: In the field of solid-state chemical hydrogen storage, ammonia borane NH{sub 3}BH{sub 3} has been widely studied while hydrazine borane N{sub 2}H{sub 4}BH{sub 3} can be considered as a “novel” material. In the present work, we investigated the behaviour of these boranes when mixed together in a mole ratio of 1:1. Hydrazine borane and ammonia borane destabilize each other. Though stable at 20–25 °C, the mixture melts at ∼30 °C and then undergoes significant decomposition, with desorption of hydrogen H{sub 2} and hydrazine N{sub 2}H{sub 4} from 67 °C. This is explained by the fact that the presence of hydrazine borane disrupts the H{sup δ+}⋯H{sup δ−} network of ammonia borane, and vice versa; the mixture is then much less stable than the pristine boranes. The mixture can nevertheless be stabilized (by heat- or vacuum-treatment and thus extraction of evolving hydrogen and hydrazine), making the as-obtained solid a potential chemical hydrogen storage material. Over the range 25–300 °C, it is able to release ca. 11.4 wt% of almost pure H{sub 2}. Furthermore forms boron nitride as the solid residue, at temperatures as low as 300 °C.

  8. Multidisciplinary Design Optimization and Analysis of Hydrazine Monopropellant Propulsion System

    Directory of Open Access Journals (Sweden)

    Amirhossein Adami

    2015-01-01

    Full Text Available Monopropellant propulsion systems are widely used especially for low cost attitude control or orbit correction (orbit maintenance. To optimize the total propulsion system, subsystems should be optimized. Chemical decomposition, aerothermodynamics, and structure disciplines demand different optimum condition such as tank pressure, catalyst bed length and diameter, catalyst bed pressure, and nozzle geometry. Subsystem conflicts can be solved by multidisciplinary design optimization (MDO technique with simultaneous optimization of all subsystems with respect to any criteria and limitations. In this paper, monopropellant propulsion system design algorithm is presented and the results of the proposed algorithm are validated. Then, multidisciplinary design optimization of hydrazine propulsion system is proposed. The goal of optimization can be selected as minimizing the total mass (including propellant, minimizing the propellant mass (maximizing the Isp, or minimizing the dry mass. Minimum total mass, minimum propellant mass, and minimum dry mass are derived using MDO technique. It is shown that minimum total mass, minimum dry mass, and minimum propellant mass take place in different conditions. The optimum parameters include bed-loading, inlet pressure, mass flow, nozzle geometry, catalyst bed length and diameter, propellant tank mass, specific impulse (Isp, and feeding mass which are derived using genetic algorithm (GA.

  9. Potentiation of cardiovascular responses to hydralazine by diverse hydrazine derivatives.

    Science.gov (United States)

    Vidrio, H

    1994-10-01

    After the observation that in anesthetized rats the antitubercular agent isoniazid potentiates the hypotensive effect of the vasodilator hydralazine (H) and transforms the accompanying reflex tachycardia to bradycardia, a number of hydrazine (HYD) derivatives were tested for this interaction in pentobarbital-anesthetized rats. All HYDs studied elicited this response in varying degrees, isoniazid, thiosemicarbazide and thiocarbohydrazide being the most active. Experiments were then carried out to explore the possibility of an influence of the HYDs on reflex reactions to H due to interaction with pyridoxal, inhibition of glutamic acid decarboxylase and decreased levels of brain gamma-aminobutyric acid. Although the H-HYDs interaction was prevented by vagotomy, it was unaffected by exogenous pyridoxal, did not occur with the alpha adrenergic antagonist prazosin and was not mimicked by non-HYD pyridoxal reactors. In other experiments, pharmacokinetic interactions and monoamine oxidase inhibition were ruled out as alternative explanations for this phenomenon. It was concluded that the H-HYDs interaction is not related to a possible influence of these drugs on central gamma-aminobutyric acid cardiovascular regulation and that other presently unknown mechanisms are involved.

  10. Compositional differentiation of Enceladus' plume

    Science.gov (United States)

    Khawaja, N.; Postberg, F.; Schmidt, J.

    2014-04-01

    The Cosmic Dust Analyser (CDA) on board the Cassini spacecraft sampled Enceladus' plume ice particles emanated directly from Enceladus' fractured south polar terrain (SPT), the so-called "Tiger Stripes", during two consecutive flybys (E17 and E18) in 2012. The spacecraft passed through the dense plume with a moderate velocity of ~7.5km/s, horizontally to the SPT with a closest approach (CA) at an altitude of ~75km almost directly over the south pole. In both flybys, spectra were recorded during a time interval of ~ ±3 minutes with respect to the closest approach achieving an average sampling rate of about 0.6 sec-1. We assume that the spacecraft passed through the plume during an interval of about ±60(sec) from the CA. Particles encountered before and after this period are predominately from the E-ring background in which Enceladus is embedded. Most CDA TOF-mass spectra are identified as one of three compositional types: (i) almost pure water (ii) organic rich and (iii) salt rich [2]. A Boxcar Analysis (BCA) is performed from a count database for compositional mapping of the plume along the space-craft trajectory. In BCA, counts of each spectrum type are integrated for a certain interval of time (box size). The integral of counts represents frequencies of compositional types in absolute abundances, which are converted later into proportions. This technique has been proven to be a suitable for inferring the compositional profiles from an earlier flyby (E5) [1]. The inferred compositional profiles show similar trends on E17 and E18. The abundances of different compositional types in the plume clearly differ from the Ering background and imply a compositional differentiation inside the plume. Following up the work of Schmidt et al, 2008 and Postberg et al, 2011 we can link different compositional types to different origins. The E17/E18 results are compared with the E5 flyby in 2008, which yielded the currently best compositional profile [2] but was executed at much

  11. On the great plume debate

    Institute of Scientific and Technical Information of China (English)

    Yaoling Niu

    2005-01-01

    @@ 1 Introductory note Geological processes are ultimately consequences of Earth's thermal evolution. Plate tectonic theory, which explains geological phenomena along plate boundaries, elegantly illustrates this concept. For example, the origin of oceanic plates at ocean ridges, the movement and growth of these plates, and their ultimate consumption back into the Earth's deep interior through subduction zones provide an efficient mechanism to cool the earth's mantle, leading to large-scale mantle convection. Mantle plumes, which explain another set of global geological phenomena such as within-plate volcanism, cool the earth's deep interior (probably the Earth's core) and represent another mode of Earth's thermal convection. Plate tectonic theory and mantle plume hypothesis thus complement each other to explain much of the whole picture of Earth processes and phenomena.

  12. Adjustable hydrazine modulation of single-wall carbon nanotube network field effect transistors from p-type to n-type

    Science.gov (United States)

    Dai, Ruixuan; Xie, Dan; Xu, Jianlong; Sun, Yilin; Sun, MengXing; Zhang, Cheng; Li, Xian

    2016-11-01

    Single-wall carbon nanotube (SWCNT) network field effect transistors (FETs), which show decent p-type electronic properties, have been fabricated. The use of hydrazine as an aqueous solution and a strong n-type dopant for the SWCNTs is demonstrated in this paper. The electrical properties are obviously tuned by hydrazine treatment at different concentrations on the surface of the SWCNT network FETs. The transport behavior of SWCNTs can be modulated from p-type to n-type, demonstrating the controllable and adjustable doping effect of hydrazine. With a higher concentration of hydrazine, more electrons can be transferred from the hydrazine molecules to the SWCNT network films, thus resulting in a change of threshold voltage, carrier mobility and on-current. By cleaning the device, the hydrazine doping effects vanish, which indicates that the doping effects of hydrazine are reversible. Through x-ray photoelectron spectroscopy (XPS) characterization, the doping effects of hydrazine have also been studied.

  13. Flow injection chemiluminescence determination of hydrazine by oxidation with chlorinated isocyanurates.

    Science.gov (United States)

    Safavi, Afsaneh; Karimi, Mohammad Ali

    2002-10-16

    A rapid and sensitive flow injection chemiluminescence (CL) method is described for the determination of hydrazine based on the CL generated during its reaction with either sodium dichloroisocyanurate (SDCC) or trichloroisocyanuric acid (TCCA) in alkaline medium. The emission intensity is greatly enhanced if dichlorofluorescein (DCF) as sensitizer is present in the reaction medium. The presence of citrate prevents the precipitation of some cations in the reaction medium and also causes an enhancement in emission intensity. The effect of analytical and flow injection variables on these CL systems and determination of hydrazine are discussed. The optimum parameters for the determination of hydrazine were studied and were found to be the following: SDCC and TCCA both 1x10(-3) M; NaOH, 2x10(-1) M; DCF, 5x10(-6) M; citrate, 1x10(-3) M and flow rate, 3.8 ml min(-1). The optimized method yielded 3sigma detection limits of 2x10(-7) and 3x10(-7) M for hydrazine with SDCC and TCCA oxidants, respectively. The method is simple, fast, sensitive, and precise and was applied to the determination of hydrazine in water samples.

  14. Preparation of fine nickel powders via reduction of nickel hydrazine complex precursors

    Institute of Scientific and Technical Information of China (English)

    HUANG Guo-yong; XU Sheng-ming; XU Gang; LI Lin-yan; ZHANG Li-feng

    2009-01-01

    Fine nickel(Ni) powders with controllable particle sizes were synthesized via the reduction of nickel hydrazine complex precursors of pure [Ni(N2H4)2]Cl2 and a mixture of [Ni(N2H4)2]Cl2 and [Ni(N2H4)3]Cl2 in aqueous solution. The mechanism of the formation of metallic Ni powders experiences the reduction of nickel hydroxide by hydrazine released from the ligand exchange reaction between nickel hydrazine complex and NaOH. In comparison with the method of preparing Ni powders from nickel salts, the method of making Ni powders via the reduction of nickel hydrazine complex precursors shows the advantages of using half dosage of hydrazine for complete reduction of nickel ions in solution, and the obtained Ni particles show less agglomeration and better dispersibility. Moreover, the average particle size of nickel powders can be controlled from 180 to 260 nm by adjusting the reaction molar ratio and concentration.

  15. PLUMED 2: New feathers for an old bird

    CERN Document Server

    Tribello, Gareth A; Branduardi, Davide; Camilloni, Carlo; Bussi, Giovanni

    2014-01-01

    Enhancing sampling and analyzing simulations are central issues in molecular simulation. Recently, we introduced PLUMED, an open-source plug-in that provides some of the most popular molecular dynamics (MD) codes with implementations of a variety of different enhanced sampling algorithms and collective variables (CVs). The rapid changes in this field, in particular new directions in enhanced sampling and dimensionality reduction together with new hardwares, require a code that is more flexible and more efficient. We therefore present PLUMED 2 here - a complete rewrite of the code in an object-oriented programming language (C++). This new version introduces greater flexibility and greater modularity, which both extends its core capabilities and makes it far easier to add new methods and CVs. It also has a simpler interface with the MD engines and provides a single software library containing both tools and core facilities. Ultimately, the new code better serves the ever-growing community of users and contribut...

  16. Formulation & Storage Studies on Hydrazine-Based Gelled Propellants.

    Directory of Open Access Journals (Sweden)

    Mohan Verma

    1996-12-01

    Full Text Available The current trend in the area of high energy storable liquid rocket propellant research is to develop gelled/metallized systems and to explore the feasibility of their application in rocket motors. The idea stems from the fact that the conversion of a conventional liquid propellant to a gelled state and its subsequent metallization has the potential to significantly enhance the performance and density specific impulse. However, it is mandatory that the gelation of the liquid propellant be brought about with a minimum concentration of gellant and the gel formed should show a shear-thinning behaviour and good storage life. Keeping this in view, an experimental program to prepare thixotropic gels of hydrazine and its methyl substitutedderivatives like monomethyl hydrazineand unsymmetrical dimethyl hydrazinewas conducted under ambient conditions. The gellants investigated included particulate, chemical and synthetic materials. The gelation of the liquid fuels ..ould be brought about with gellant concentration as low as I wt per cent in some cases. Metallized gels using up to 40 wt per cent of AlIMg metal powders could be formulated. These heterogeneous systems showed a reduction in critical gellant concentration with degree of metallization. Further, less gelation time is observed if the gellant concentration is kept fixed and metal content is increased. The storage studies on gelled systems conducted over a period of three months showed good stability. The metallized systems, however, showed the settling of metal powders in meagre concentration which does not pose a major problem as these gels could be re-homogenized with stirring.

  17. Arrays of TiO2 Nanowires as Photoelectrochemical Sensors for Hydrazine Detection

    Directory of Open Access Journals (Sweden)

    Michael Ongaro

    2015-05-01

    Full Text Available Electrodes based on arrays of TiO2 nanowires were prepared by template sol-gel synthesis with the goal of developing a hydrazine photoelectrochemical sensor. Experimental conditions were chosen so that the gelation reaction occurred inside the nanopores of track-etched polycarbonate membranes, with consequent filling with TiO2 nanowires. Different procedures for the removal of the template were examined, in order to obtain arrays of self-standing TiO2 nanowires. The nanowire arrays were bound to fluorine doped tin oxide substrates to produce handy photoelectrodes. The photocurrent recorded with the photoelectrodes in the presence of hydrazine showed significant dependence on the pollutant concentration. The development of a photoelectrochemical sensor for hydrazine detection in water samples, based on this principle, is presented.

  18. Efficient hydrogen evolution in transition metal dichalcogenides via a simple one-step hydrazine reaction

    Science.gov (United States)

    Cummins, Dustin R.; Martinez, Ulises; Sherehiy, Andriy; Kappera, Rajesh; Martinez-Garcia, Alejandro; Schulze, Roland K.; Jasinski, Jacek; Zhang, Jing; Gupta, Ram K.; Lou, Jun; Chhowalla, Manish; Sumanasekera, Gamini; Mohite, Aditya D.; Sunkara, Mahendra K.; Gupta, Gautam

    2016-01-01

    Hydrogen evolution reaction is catalysed efficiently with precious metals, such as platinum; however, transition metal dichalcogenides have recently emerged as a promising class of materials for electrocatalysis, but these materials still have low activity and durability when compared with precious metals. Here we report a simple one-step scalable approach, where MoOx/MoS2 core-shell nanowires and molybdenum disulfide sheets are exposed to dilute aqueous hydrazine at room temperature, which results in marked improvement in electrocatalytic performance. The nanowires exhibit ∼100 mV improvement in overpotential following exposure to dilute hydrazine, while also showing a 10-fold increase in current density and a significant change in Tafel slope. In situ electrical, gate-dependent measurements and spectroscopic investigations reveal that hydrazine acts as an electron dopant in molybdenum disulfide, increasing its conductivity, while also reducing the MoOx core in the core-shell nanowires, which leads to improved electrocatalytic performance. PMID:27282871

  19. Surface-catalyzed air oxidation reactions of hydrazines: Tubular reactor studies

    Science.gov (United States)

    Kilduff, Jan E.; Davis, Dennis D.; Koontz, Steven L.

    1988-01-01

    The surface-catalyzed air oxidation reactions of hydrazine, monomethylhydrazine, unsymmetrical dimethylhydrazine, symmetrical dimethylhydrazine, trimethylhydrazine and tetramethylhydrazine were investigated in a metal-powder packed turbular flow reactor at 55 plus or minus 3 C. Hydrazine was completely reacted on all surfaces studied. The major products of monomethylhydrazine (MMH) oxidation were methanol, methane and methyldiazene. The di-, tri- and tetra-methyl hydrazines were essentially unreactive under these conditions. The relative catalytic reactivities toward MMH are: Fe greater than Al2O3 greater than Ti greater than Zn greater than 316 SS greater than Cr greater than Ni greater than Al greater than 304L SS. A kinetic scheme and mechanism involving adsorption, oxidative dehydrogenation and reductive elimination reactions on a metal oxide surface are proposed.

  20. Study of Plume Impingement Effects in the Lunar Lander Environment

    Science.gov (United States)

    Marichalar, Jeremiah; Prisbell, A.; Lumpkin, F.; LeBeau, G.

    2010-01-01

    Plume impingement effects from the descent and ascent engine firings of the Lunar Lander were analyzed in support of the Lunar Architecture Team under the Constellation Program. The descent stage analysis was performed to obtain shear and pressure forces on the lunar surface as well as velocity and density profiles in the flow field in an effort to understand lunar soil erosion and ejected soil impact damage which was analyzed as part of a separate study. A CFD/DSMC decoupled methodology was used with the Bird continuum breakdown parameter to distinguish the continuum flow from the rarefied flow. The ascent stage analysis was performed to ascertain the forces and moments acting on the Lunar Lander Ascent Module due to the firing of the main engine on take-off. The Reacting and Multiphase Program (RAMP) method of characteristics (MOC) code was used to model the continuum region of the nozzle plume, and the Direct Simulation Monte Carlo (DSMC) Analysis Code (DAC) was used to model the impingement results in the rarefied region. The ascent module (AM) was analyzed for various pitch and yaw rotations and for various heights in relation to the descent module (DM). For the ascent stage analysis, the plume inflow boundary was located near the nozzle exit plane in a region where the flow number density was large enough to make the DSMC solution computationally expensive. Therefore, a scaling coefficient was used to make the DSMC solution more computationally manageable. An analysis of the effectiveness of this scaling technique was performed by investigating various scaling parameters for a single height and rotation of the AM. Because the inflow boundary was near the nozzle exit plane, another analysis was performed investigating three different inflow contours to determine the effects of the flow expansion around the nozzle lip on the final plume impingement results.

  1. Electroless plating of Ni-B film as a binder-free highly efficient electrocatalyst for hydrazine oxidation

    Science.gov (United States)

    Wen, Xiao-Ping; Dai, Hong-Bin; Wu, Lin-Song; Wang, Ping

    2017-07-01

    Hydrazine is a promising energy carrier for fuel cells owing to its combined advantages of high theoretical cell voltage, high-power density, and no greenhouse gas emission. By using an electroless plating process, we have prepared a robust Ni-B film grown on Ni foam that is highly effective for hydrazine electrooxidation in alkaline media. The effects of reaction temperature, concentrations of hydrous hydrazine and sodium hydroxide in the fuel solution on performance of hydrazine electrooxidation reaction are investigated. The mechanistic reason for the property advantage of as-prepared Ni-B/Ni foam catalyst over the relevant catalysts is discussed based on careful kinetics studies and characterization. The facile synthesis of Ni-based catalyst with high activity and good stability is of clear significance for the development of hydrous hydrazine as a viable energy carrier.

  2. Synthesis, characterization and antioxidant study of N,N’-bis(2-chlorobenzamidothiocarbonyl)hydrazine

    Energy Technology Data Exchange (ETDEWEB)

    Firdausiah, Syadza; Hasbullah, Siti Aishah; Yamin, Bohari M. [School of Chemical Science and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2015-09-25

    N,N’-bis(2-chlorobenzamidothiocarbonyl)hydrazine was synthesized from 2-chlorobenzoylisothiocyanate and hydrazine in acetone. The compound was characterized by infrared, {sup 1}H and {sup 13}C NMR, and UV-Vis spectroscopies. X-ray crystallography study showed the molecule adopt trans configuration at both N-N and C-N bonds. The compound showed high antioxidant activity, EC{sub 50} of 374.89 µM, compared to ascorbic acid (EC{sub 50} of 561.36 µM)

  3. Selective fluorescent detection of aspartic acid and glutamic acid employing dansyl hydrazine dextran conjugate.

    Science.gov (United States)

    Nasomphan, Weerachai; Tangboriboonrat, Pramuan; Tanapongpipat, Sutipa; Smanmoo, Srung

    2014-01-01

    Highly water soluble polymer (DD) was prepared and evaluated for its fluorescence response towards various amino acids. The polymer consists of dansyl hydrazine unit conjugated into dextran template. The conjugation enhances higher water solubility of dansyl hydrazine moiety. Of screened amino acids, DD exhibited selective fluorescence quenching in the presence of aspartic acid (Asp) and glutamic acid (Glu). A plot of fluorescence intensity change of DD against the concentration of corresponding amino acids gave a good linear relationship in the range of 1 × 10(-4) M to 25 × 10(-3) M. This establishes DD as a potential polymeric sensor for selective sensing of Asp and Glu.

  4. Kinetic Study of Np(Ⅵ) Reduction With Tert-butyl Hydrazine

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Tert-butyl hydrazine(TBH) is a new salt free reductant, it can effectively reduce Np(Ⅵ) to Np(Ⅴ) but reduce Pu(Ⅳ)very slowly. Further more, it has the highest ratio of rate constant for Np(Ⅵ) reduction to the rate constant for Pu(Ⅳ) reduction in hydrazine derivatives, so it’s a promising reductant to separate Np, Pu effectively,Reduction kinetic study of the reaction in nitric acid is performed by spectrophotometry. The effect of some factors such as concentration of TBH, HNO3, Np(Ⅵ) and temperature on the redox

  5. The effect of hydrazine intercalation on the structure and capacitance of 2D titanium carbide (MXene).

    Science.gov (United States)

    Mashtalir, O; Lukatskaya, M R; Kolesnikov, A I; Raymundo-Piñero, E; Naguib, M; Barsoum, M W; Gogotsi, Y

    2016-04-28

    Herein we show that hydrazine intercalation into 2D titanium carbide (Ti3C2-based MXene) results in changes in its surface chemistry by decreasing the amounts of fluorine, OH surface groups and intercalated water. It also creates a pillaring effect between Ti3C2Tx layers pre-opening the structure and improving the accessability to active sites. The hydrazine treated material has demonstrated a greatly improved capacitance of 250 F g(-1) in acidic electrolytes with an excellent cycling ability for electrodes as thick as 75 μm.

  6. Transformation of Hydrazine Fuels in Soil%肼类燃料在土壤中迁移转化

    Institute of Scientific and Technical Information of China (English)

    任向红

    2001-01-01

    Adsorption, degradation, transformation of hydrazines, methyl hydrazines and unsymmetrical dimethyl hydrazines in soil and their toxicity to microorganisms in soil are evaluated in the present investigation. It may be concluded that principal reactions between the hydrazine fuels and clay are physical absorption and chemical degradation. It has also been found that ion- exchange can only occur at low pH level, the unsolvable hydroxides may be formed on surface of the soil, suggesting that those could combine lots of hydrazine fuels by hydrogen- bond and ionization at the high pH level. The order of toxicity of the hydrazine fuels to microorganisms is hydrazines>methyl hydrazines> unsymmetrical dimethyl hydrazines. It has been indicated that some microorganisms in the soil can degrade the hydrazine fuels.%论述了对肼、甲基肼和偏二甲肼在土壤环境中的吸附、降解、迁移转化模型及对土壤中的微生物的毒性。肼类燃料在土壤环境中与粘土的作用最强,主要存在着物理吸附与化学降解两个方面。pH值较低时,在粘土中主要是可逆离子交换;pH值较高时,在土壤表面形成不溶的氢氧化物,通过氢键和离子作用结合大量肼类燃料。肼类燃料对土壤中的微生物的毒性大小是肼>甲基肼>偏二甲肼,土壤中的某些微生物也可促进肼类燃料的降解。

  7. Plumes and Earth's Dynamic History : from Core to Biosphere

    Science.gov (United States)

    Courtillot, V. E.

    2002-12-01

    the order of 10 Ma or less, often resulting in continental breakup; the bulk of the volume actually erupted in 1 Ma or less. This makes LIPs the remnants of major geodynamic events, with fluxes possibly matching, over short time scales, the crustal production of mid-ocean ridges. The correlation between trap ages, extinctions and oceanic anoxia events proposed over a decade ago has improved steadily, to the point that trap ages may form much of the underlying structure of the geological time scale. The five largest mass extinctions in the last 260 Ma coincide with five traps, making a causal connection between the two unavoidable. The plume hypothesis provides a useful and exciting complement to the now conventional plate tectonics paradigm, and can provide a unified underlying mechanism to explain the few, key times when Earth's dynamics behaved in a rather catastrophic way, of which our current world bears the memory. Plumes may express couplings between the Earth's very different envelopes. They are a singular mode in which the Earth's engine liberates its heat when normal plate tectonics do not suffice. They may modulate the intensity of many global phenomena, from reversal frequency generated in the liquid core to major continental breakup and finally to mass extinctions. The remarkably rich, diverse and exciting geophysical disciplines of geomagnetism and paleomagnetism, which are the lecturer's main practical tools, have provided many of the key observations that have led to this view.

  8. Relationship between plume and plate tectonics

    Science.gov (United States)

    Puchkov, V. N.

    2016-07-01

    The relationship between plate- and plume-tectonics is considered in view of the growth and breakdown of supercontinents, active rifting, the formation of passive volcanic-type continental margins, and the origin of time-progressive volcanic chains on oceanic and continental plates. The mantle wind phenomenon is described, as well as its effect on plume morphology and anisotropy of the ambient mantle. The interaction of plumes and mid-ocean ridges is discussed. The principles and problems of plume activity analysis in subduction- and collision-related foldbelts are considered and illustrated with examples.

  9. Redox conditions for mantle plumes

    Science.gov (United States)

    Heister, L. E.; Lesher, C. E.

    2005-12-01

    The vanadium to scandium ratio (V/Sc) for basalts from mid-ocean ridge (MOR) and arc environments has been proposed as a proxy for fO2 conditions during partial melting (e.g. [1] and [2]). Contrary to barometric measurements of the fO2 of primitive lavas, the V/Sc ratio of the upper mantle at mid-ocean ridges and arcs is similar, leading previous authors to propose that the upper mantle has uniform redox potential and is well-buffered. We have attempted to broaden the applicability of the V/Sc parameter to plume-influenced localities (both oceanic and continental), where mantle heterogeneities associated with recycled sediments, mafic crust, and metasomatized mantle, whether of shallow or deep origin, exist. We find that primitive basalts from the North Atlantic Igneous Province (NAIP), Hawaii (both the Loa and Kea trends), Deccan, Columbia River, and Siberian Traps show a range of V/Sc ratios that are generally higher (average ~9) than those for MOR (average ~ 6.7) or arc (average ~7) lavas. Based on forward polybaric decompression modeling, we attribute these differences to polybaric melting and melt segregation within the garnet stability field rather than the presence of a more oxidized mantle in plume-influenced settings. Like MORB, the V/Sc ratios for plume-influenced basalts can be accounted for by an oxidation state approximately one log unit below the Ni-NiO buffer (NNO-1). Our analysis suggests that source heterogeneities have little, if any, resolvable influence on mantle redox conditions, although they have significant influence on the trace element and isotopic composition of mantle-derived melts. We suggest that variations in the redox of erupted lavas is largely a function of shallow lithospheric processes rather than intrinsic to the mantle source, regardless of tectonic setting. [1] Li and Lee (2004) EPSL, [2] Lee et al. (2005) J. of Petrology

  10. Pulsed Plasma Thruster plume analysis

    Energy Technology Data Exchange (ETDEWEB)

    Parker, K. [Washington Univ., Aerospace and Energetics Research Program, Seattle, WA (United States)

    2003-11-01

    Micro-Pulsed Plasma Thrusters ({mu}PPTs) are a promising method for precision attitude control for small spacecraft in formation flying. They create an ionized plasma plume, which may interfere with other spacecraft in the formation. To characterize the ions in the plume, a diagnostic has been built that couples a drift tube with an energy analyzer. The drift tube provides time of flight measurements to determine the exhaust velocity, and the energy analyzer discriminates the ion energies. The energy analyzer measures the current on a collector plate downstream of four grids that repel electrons and ions below a specified energy. The first grid lowers the density of the plasma, therefore increasing Debye length. The second and fourth grids have a negative potential applied to them so they repel the electrons, while the third grid's voltage can be varied to repel lower energy ions. The ion energies can be computed by differentiating the data. Combining the information of the ion energies and their velocities identifies the ion masses in the PPT plume. The PPT used for this diagnostic is the micro-PPT developed for the Dawgstar satellite. This PPT uses 5.2 Joules per pulse and has a 2.3 cm{sup 2} propellant area, a 1.3 cm electrode length, and an estimated thrust of 85 {mu}N [C. Rayburn et al., AIAA-2000-3256]. This paper will describe the development and design of the time of flight/gridded energy analyzer diagnostic and present recent experimental results. (Author)

  11. Plume spread and atmospheric stability

    Energy Technology Data Exchange (ETDEWEB)

    Weber, R.O. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The horizontal spread of a plume in atmospheric dispersion can be described by the standard deviation of horizontal direction. The widely used Pasquill-Gifford classes of atmospheric stability have assigned typical values of the standard deviation of horizontal wind direction and of the lapse rate. A measured lapse rate can thus be used to estimate the standard deviation of wind direction. It is examined by means of a large dataset of fast wind measurements how good these estimates are. (author) 1 fig., 2 refs.

  12. Characteristics of bubble plumes, bubble-plume bubbles and waves from wind-steepened wave breaking

    NARCIS (Netherlands)

    Leifer, I.; Caulliez, G.; Leeuw, G. de

    2007-01-01

    Observations of breaking waves, associated bubble plumes and bubble-plume size distributions were used to explore the coupled evolution of wave-breaking, wave properties and bubble-plume characteristics. Experiments were made in a large, freshwater, wind-wave channel with mechanical wind-steepened w

  13. Preparation of FeO(OH Modified with Polyethylene Glycol and Its Catalytic Activity on the Reduction of Nitrobenzene with Hydrazine Hydrate

    Directory of Open Access Journals (Sweden)

    Ke Ying Cai

    2016-10-01

    Full Text Available Iron oxyhydroxide was prepared by dropping ammonia water to Fe(NO33.9H2O dispersed in polyethylene glycol (PEG 1000. The catalyst was characterized by X-ray powder diffraction, Fourier transform infrared spectroscopy and laser particle size analyzer. The results showed the catalyst modified with polyethylene glycol was amorphous. The addition of PEG during the preparation make the particle size of the catalyst was smaller and more uniform. The catalytic performance was tested in the reduction of nitroarenes to corresponding amines with hydrazine hydrate, and the catalyst showed excellent activity and stability. Copyright © 2016 BCREC GROUP. All rights reserved Received: 2nd February 2016; Revised: 26th April 2016; Accepted: 7th June 2016 How to Cite: Cai, K.Y., Liu, Y.S., Song, M., Zhou, Y.M., Liu, Q., Wang, X.H. (2016. Preparation of FeO(OH Modified with Polyethylene Glycol and Its Catalytic Activity on the Reduction of Nitrobenzene with Hydrazine Hydrate. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (3: 363-368 (doi:10.9767/bcrec.11.3.576.363-368 Permalink/DOI: http://doi.org/10.9767/bcrec.11.3.576.363-368

  14. Radiation Chemistry of Potential Europa Plumes

    Science.gov (United States)

    Gudipati, M. S.; Henderson, B. L.

    2014-12-01

    Recent detection of atomic hydrogen and atomic oxygen and their correlation to potential water plumes on Europa [Roth, Saur et al. 2014] invoked significant interest in further understanding of these potential/putative plumes on Europa. Unlike on Enceladus, Europa receives significant amount of electron and particle radiation. If the plumes come from trailing hemisphere and in the high radiation flux regions, then it is expected that the plume molecules be subjected to radiation processing. Our interest is to understand to what extent such radiation alterations occur and how they can be correlated to the plume original composition, whether organic or inorganic in nature. We will present laboratory studies [Henderson and Gudipati 2014] involving pulsed infrared laser ablation of ice that generates plumes similar to those observed on Enceladus [Hansen, Esposito et al. 2006; Hansen, Shemansky et al. 2011] and expected to be similar on Europa as a starting point; demonstrating the applicability of laser ablation to simulate plumes of Europa and Enceladus. We will present results from electron irradiation of these plumes to determine how organic and inorganic composition is altered due to radiation. Acknowledgments:This research was enabled through partial funding from NASA funding through Planetary Atmospheres, and the Europa Clipper Pre-Project. B.L.H. acknowledges funding from the NASA Postdoctoral Program for an NPP fellowship. Hansen, C. J., L. Esposito, et al. (2006). "Enceladus' water vapor plume." Science 311(5766): 1422-1425. Hansen, C. J., D. E. Shemansky, et al. (2011). "The composition and structure of the Enceladus plume." Geophysical Research Letters 38. Henderson, B. L. and M. S. Gudipati (2014). "Plume Composition and Evolution in Multicomponent Ices Using Resonant Two-Step Laser Ablation and Ionization Mass Spectrometry." The Journal of Physical Chemistry A 118(29): 5454-5463. Roth, L., J. Saur, et al. (2014). "Transient Water Vapor at Europa's South

  15. Variability and Composition of Io's Pele Plume

    Science.gov (United States)

    Jessup, K. L.; Spencer, J.; Yelle, R.

    2004-11-01

    The Pele plume is one of the largest and most dynamic of the plumes on Io. While sulfur dioxide (SO2) gas was always assumed to be a constituent of this plume, spectral observations obtained in 1999 were the first to positively identify elemental sulfur (S2) (Spencer et al. 2000) within the Pele plume. The S2/SO2 ratio derived from this observation provided a critical component necessary for the constraint of the magma chemistry and vent conditions of the Pele plume (Zolotov and Fegley 1998). But, because the Pele plume has long been known to be variable in its eruptive behavior, it is not likely that the vent conditions are invariant. Consequently, additional observations were needed to constrain the extent of the variability of the plume's composition and gas abundances. To this end, in February 2003, March 2003 and January 2004 we obtained spectra of Pele with Hubble's Space Telescope Imaging Spectrograph (STIS) in transit of Jupiter, using the 0.1 arcsec slit, for the wavelength region extending from 2100-3100 Å. Contemporaneous with the spectral data we also obtained UV and visible-wavelength images of the plume in reflected sunlight with the Advanced Camera for Surveys (ACS) prior to Jupiter transit, in order to constrain plume dust abundance. The newly acquired STIS data show both the S2 and SO2 absorption signatures, and provide concrete evidence of temporal variability in the abundance of these gases. Likewise, the degree of dust scattering recorded in the ACS data varied as a function of the date of observation. We will present preliminary constraints on the composition and variability of the gas abundances of the Pele plume as recorded within the STIS data. We will also give a brief overview of the variability of the plume dust signatures relative to the gas signatures as a function of time.

  16. Proceedings of plumes, plates and mineralisation symposium: an introduction

    CSIR Research Space (South Africa)

    Hatton, CJ

    1997-12-01

    Full Text Available of plume-theory. Mechanisms of magma formation are identified and plume positions and distances to their surface expression considered. Mantle plumes are considered as a heat and fluid source for the Witwatersrand gold deposits....

  17. Laser optogalvanic spectroscopy of neon in a discharge plasma and modeling and analysis of rocket plume RF-line emissions

    Science.gov (United States)

    Ogungbemi, Kayode I.

    databases (e.g. JPL/NASA and Cologne), together with other appropriate spectroscopic data. Hydrazine fuel was selected as the rocket propellant of choice and the plume codes were run by the JHU-APL research group. A representative monopropellant hydrazine plume has been determined to provide exhaust temperature, pressure, velocity, and species number density inputs for model development. A MATLAB code has been developed for computing broadside line-of-sight (LOS) intensities due to line emissions involving ammonia and other plume species. Initially, we assumed Local Thermodynamic Equilibrium (LTE) and included self-absorption contributions due to plume opacity, together with collisional and Doppler broadening, as well as the Doppler shift due to the plume radial velocity towards and away from a stationary detector. The recorded code output was MATLAB coded and an assortment of plume parameters computed, such as the volume emission rate, the absorption coefficient, optical depth and species radiance line-by-line. These parameters were computed both manually utilizing a spread sheet and then automated using the Matlab code. The volume emissions, along with other plume properties, were plotted as a function of the axial distance in the plume for several Radio Frequency (RF) transitions involving various significant plume species. Plume properties, such as the temperature, pressure, number density, and plume particulate speed emanating from the nozzle where analyzed and modeled as the plume drifts away from the rocket nozzle. Both the axial and radial distance dependences were investigated with respect to the various plume properties and parameters. Population distribution of the species (number density) dependence on the plume temperature was investigated and modeled line-by-line for each of the plume species studied at the nozzle exit plane and beyond. In addition, volume emission and absorption coefficients have been analyzed and modeled and solutions to the Radiative

  18. Plumes and Fountains in a Cross-Wind

    Science.gov (United States)

    Sutherland, Bruce; Anderson-Frey, Alexendra; Ansong, Joseph

    2010-11-01

    Sour gas flares attempt to burn off hydrogen sulfide (H2S), a poisonous gas that can kill at concentrations higher than 100PPM. Because in some areas of the Rocky Mountain foothills the concentration of the gas before burning can be has high as 20%, flaring must be extremely efficient to prevent disaster. Recent studies have shown that cross-winds can reduce the efficiency to 30% meaning the concentration of unburned gas at the source can be as high as 60000PPM. Engineers rely on atmospheric dispersion to reduce the concentration to tolerable levels before the plume extends to the ground. To predict the dispersion of the gas close to the source, the US Environmental Protection Agency uses a numerical model, AERMOD, that heuristically adapts plume theory to account for the effects of winds and atmospheric inversions. They do not account for the fact that H2S is heavier than air at room temperature and so would tend to pool in valleys after cooling. We have performed laboratory experiments to examine the dynamics of positively and negatively buoyant plumes in uniform and stratified environments with a uniform background flow. The results are then compared with the predictions of the AERMOD model.

  19. A Hydrazine-Free Wolff-Kishner Reaction Suitable for an Undergraduate Laboratory

    Science.gov (United States)

    Cranwell, Philippa B.; Russell, Andrew T.

    2016-01-01

    A Wolff-Kishner reaction that does not require hydrazine has been developed. The reaction sequence has two steps: formation of a carbomethoxyhydrazone from methyl hydrazinocarboxylate and acetophenone, then decomposition of this intermediate by treatment with potassium hydroxide in triethylene glycol. Purification is by filtration through a plug…

  20. Hydrazine Blending and Storage Facility Wastewater Treatment and Decommissioning Assessment. Version 3.1

    Science.gov (United States)

    1988-06-01

    concrete pads and dikes; a drum storage I 6764a 1-5 05 -- iti kwij 1-6a pad; a storage shed; a tool shed; an office shed, and associated Ipiping . Two... Oceanic and Atnospheric Administration). 1983. Local climatological data, Denver, CO. Neumann, E.J., and B. Jody. 1986. Neutralization of hydrazine

  1. X-ray absorption spectroscopy study on the thermal and hydrazine reduction of graphene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Xianqing, E-mail: lxq@gxu.edu.cn [The Colleague of Physics Science and Technology, Guangxi University, Nanning 530004 (China); Wang, Yu [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China); Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China); Zheng, Huiyuan [The Colleague of Physics Science and Technology, Guangxi University, Nanning 530004 (China); Wu, Ziyu, E-mail: wuzy@ustc.edu.cn [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China)

    2014-10-15

    Highlights: • XAS study of GO and reduced GO was performed. • Detailed evolution of the electronic structures and chemical bonding of GO was revealed. • A new efficient route for the reduction of GO is proposed. - Abstract: X-ray absorption spectroscopy (XAS) was applied to systemically investigate the deoxygenation of graphene oxide (GO) via annealing and hydrazine treatment. Detailed evolution of the electronic structures and chemical bonding of GO was presented. The enhanced intensity of π{sup *} resonance and the appearance of splitting σ{sup *} resonance in C K-edge XAS spectra suggest high extents of recoveries of π-conjugation upon reduction using thermal annealing or hydrazine. Experimental results revealed that the carboxyl as well as epoxide and hydroxyl groups on the surface of GO were thermally reduced first, followed by the more difficult removal of carbonyl and cyclic ether groups at higher temperatures. The hydrazine reduction could remove epoxide, hydroxyl and carboxyl groups effectively, whereas the carbonyl groups were partially reduced with the incorporation of nitrogen species simultaneously. The residual oxygen functional groups on hydrazine-reduced GO could be further removed after modest thermal annealing. It was proposed that a combination of both types of reductions would give the best deoxygenation efficiency for the production of graphene.

  2. Kinetic Study of the Reaction between Tert-butyl Hydrazine and Nitrous Acid

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The kinetic study of the reaction between tert-butyl hydrazine(TBH)and nitrous acid in nitric acid system is performed by spectrophotometry. The effect of some factors such as the concentration of TBH, the concentration of nitric acid, ionic strength, temperature and the

  3. The effect of hydrazine intercalation on the structure and capacitance of 2D titanium carbide (MXene)

    Science.gov (United States)

    Mashtalir, O.; Lukatskaya, M. R.; Kolesnikov, A. I.; Raymundo-Piñero, E.; Naguib, M.; Barsoum, M. W.; Gogotsi, Y.

    2016-04-01

    Herein we show that hydrazine intercalation into 2D titanium carbide (Ti3C2-based MXene) results in changes in its surface chemistry by decreasing the amounts of fluorine, OH surface groups and intercalated water. It also creates a pillaring effect between Ti3C2Tx layers pre-opening the structure and improving the accessability to active sites. The hydrazine treated material has demonstrated a greatly improved capacitance of 250 F g-1 in acidic electrolytes with an excellent cycling ability for electrodes as thick as 75 μm.Herein we show that hydrazine intercalation into 2D titanium carbide (Ti3C2-based MXene) results in changes in its surface chemistry by decreasing the amounts of fluorine, OH surface groups and intercalated water. It also creates a pillaring effect between Ti3C2Tx layers pre-opening the structure and improving the accessability to active sites. The hydrazine treated material has demonstrated a greatly improved capacitance of 250 F g-1 in acidic electrolytes with an excellent cycling ability for electrodes as thick as 75 μm. Electronic supplementary information (ESI) available: Characterization methods, additional XRD patterns (Fig. S1) and INS spectra (Fig. S2-S4). See DOI: 10.1039/c6nr01462c

  4. Redox conditions effect on flow accelerated corrosion: Influence of hydrazine and oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Bouvier, O. de [EDF, R and D Div., Moret sur Loing (France); Bouchacourt, M. [EDF, Engineering and Service Div., Villeurbanne (France); Fruzzetti, K. [EPRI, Science and Technology Div., Palo Alto, CA (United States)

    2002-07-01

    Flow accelerated corrosion (FAC) of carbon steels has been studied world-wide for more than twenty years and is now fairly well understood. The influence of several parameters like water chemistry (i.e. pH and oxygen content), temperature, hydrodynamic or mass transfer conditions (i.e. flow velocity, geometry, steam quality..) and steel composition on the corrosion kinetics has been demonstrated both theoretically and experimentally. However, the effect of a reducing environment and variable redox conditions have not yet been fully explored. It's well known that a reducing environment is effective in increasing the resistance of steam generator tubing to intergranular attack / stress corrosion cracking (IGA/SCC) and pitting. In that way, secondary water chemistry specifications have been modified from low hydrazine to high hydrazine chemistry in the steam-water circuit. Nevertheless, increasing hydrazine levels up to 200 {mu}g/kg could have a detrimental effect by potentially enhancing the FAC process. Moreover, in order to have a complete understanding of the possible impact of the water chemistry environment it is also important to consider the impact of redox conditions during shutdowns (cold and/or hot shutdowns) and start up periods when aerated water injections are made to maintain a constant water level in the Steam Generators from the auxiliary feedwater circuit. Therefore, a common EDF and EPRI R and D effort has been recently carried out to study the effects of hydrazine and oxygen on FAC. The results are presented as follows. (authors)

  5. Hydrazine reduction of transition metal oxides - In situ characterization using X-ray photoelectron spectroscopy

    Science.gov (United States)

    Littrell, D. M.; Tatarchuk, B. J.

    1986-01-01

    The transition metal oxides (TMOs) V2O5, FeO3, Co3O4, NiO, CuO, and ZnO were exposed to hydrazine at various pressures. The metallic surfaces were surveyed by in situ X-ray photoelectron spectroscopy to determine the irrelative rate of reduction by hydrazine. The most easily reducible oxide, CuO, could be reduced to the metallic state at room temperature and 10 to the -6th torr. The reaction is first order with respect to CuO, with an activation energy of about 35 kJ/mol. Two types of adsorption were seen to occur at 295 K: (1) a reversible component in which the measured N:Cu ratio increased to 0.60 at hydrazine pressures up to 0.5 torr, and (2) an irreversible component, with a N:Cu ratio of 0.28, which could not be removed by extended vacuum pumping. The results of this study are useful for the identification of TMO's that can be used as solid neatallizers of hydrazine spills, and for the preparation of metal surfaces for electroplating and evaporative thin-film coating.

  6. Highly selective amperometric sensor for the trace level detection of hydrazine at bismuth nanoparticles decorated graphene nanosheets modified electrode.

    Science.gov (United States)

    Devasenathipathy, Rajkumar; Mani, Veerappan; Chen, Shen-Ming

    2014-06-01

    A highly selective amperometric sensor was developed for the trace level determination of hydrazine at bismuth nanoparticles (Bi) decorated graphene nanosheets (GR) composite film modified glassy carbon electrode (GCE). GR-Bi nanocomposite has been successfully prepared via simple and facile chemical reduction approach and its structure was characterized by various techniques. Surface morphological and X-ray diffraction studies revealed the formation and high loading of Bi nanoparticles on graphene sheets. GR-Bi nanocomposite modified GCE exhibited greatly enhanced electrocatalytic performance towards electro-oxidation of hydrazine in terms of decrease in overpotential and increase in oxidation peak current (Ip). The kinetic parameters such as electron transfer coefficient (α) and diffusion coefficient (Do) of the hydrazine oxidation were determined to be 0.70 and 2.65×10(-5) cm(2) s(-1), respectively. An amperometric sensor has been fabricated which detects trace level concentration of hydrazine. The sensor exhibited a wide linear range from 20 nM to 0.28 mM and a very low detection limit (LOD) of 5 nM. Remarkably, this is the lowest LOD achieved for the determination of hydrazine in neutral pH among other reported electrochemical hydrazine sensors. In addition, the sensor selectively detects hydrazine even in the presence of 1000 fold excess quantity of common interferrants. The practical feasibility of the sensor has been assessed in water and urine samples with good recoveries. Furthermore, the sensor exhibited appreciable stability, repeatability and reproducibility results.

  7. New Modified-Multiwall Carbon Nanotubes Paste Electrode for Electrocatalytic Oxidation and Determination of Hydrazine Using Square Wave Voltammetry

    Institute of Scientific and Technical Information of China (English)

    Ali A. ENSAF; Mahsa LOTFI; Hassan KARIMI-MALEH

    2012-01-01

    The application of p-aminophenol as a suitable mediator, as a sensitive and selective voltammetric sensor for the determination of hydrazine using square wave voltammetric method were described. The modified multiwall carbon nanotubes paste electrode exhibited a good electrocatalytic activity for the oxidation of hydrazine at pH = 7.0. The catalytic oxidation peak currents showed a linear dependence of the peaks current to the hydrazine concentrations in the range of 0.5–175 μmol/L with a correlation coefficient of 0.9975. The detection limit (S/N = 3) was estimated to be 0.3 μmol/L of hydrazine. The relative standard deviations for 0.7 and 5.0 μmol/L hydrazine were 1.7 and 1.1%, respectively. The modified electrode showed good sensitivity and selectivity. The diffusion coefficient (D = 9.5 × 10–4 cm2/s) and the kinetic parameters such as the electron transfer coefficient (α = 0.7) of hydrazine at the surface of the modified electrode were determined using electrochemical approaches. The electrode was successfully applied for the determination of hydrazine in real samples with satisfactory results.

  8. Cyclic voltammetry deposition of copper nanostructure on MWCNTs modified pencil graphite electrode: An ultra-sensitive hydrazine sensor.

    Science.gov (United States)

    Heydari, Hamid; Gholivand, Mohammad B; Abdolmaleki, Abbas

    2016-09-01

    In this study, Copper (Cu) nanostructures (CuNS) were electrochemically deposited on a film of multiwall carbon nanotubes (MWCNTs) modified pencil graphite electrode (MWCNTs/PGE) by cyclic voltammetry method to fabricate a CuNS-MWCNTs composite sensor (CuNS-MWCNT/PGE) for hydrazine detection. Scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDX) were used for the characterization of CuNS on the MWCNTs matrix. The composite of CuNS-MWCNTs was characterized with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The preliminary studies showed that the proposed sensor have a synergistic electrocatalytic activity for the oxidation of hydrazine in phosphate buffer. The catalytic currents of square wave voltammetry had a linear correlation with the hydrazine concentration in the range of 0.1 to 800μM with a low detection limit of 70nM. Moreover, the amperometric oxidation current exhibited a linear correlation with hydrazine concentration in the concentration range of 50-800μM with the detection limit of 4.3μM. The proposed electrode was used for the determination of hydrazine in real samples and the results were promising. Empirical results also indicated that the sensor had good reproducibility, long-term stability, and the response of the sensor to hydrazine was free from interferences. Moreover, the proposed sensor benefits from simple preparation, low cost, outstanding sensitivity, selectivity, and reproducibility for hydrazine determination. Copyright © 2016. Published by Elsevier B.V.

  9. Numerical modeling of mantle plume diffusion

    Science.gov (United States)

    Krupsky, D.; Ismail-Zadeh, A.

    2004-12-01

    To clarify the influence of the heat diffusion on the mantle plume evolution, we develop a two-dimensional numerical model of the plume diffusion and relevant efficient numerical algorithm and code to compute the model. The numerical approach is based on the finite-difference method and modified splitting algorithm. We consider both von Neumann and Direchlet conditions at the model boundaries. The thermal diffusivity depends on pressure in the model. Our results show that the plume is disappearing from the bottom up - the plume tail at first and its head later - because of the mantle plume geometry (a thin tail and wide head) and higher heat conductivity in the lower mantle. We study also an effect of a lateral mantle flow associated with the plate motion on the distortion of the diffusing mantle plume. A number of mantle plumes recently identified by seismic tomography seem to disappear in the mid-mantle. We explain this disappearance as the effect of heat diffusion on the evolution of mantle plume.

  10. Aggregate Particles in the Plumes of Enceladus

    CERN Document Server

    Gao, Peter; Zhang, Xi; Ingersoll, Andrew P

    2015-01-01

    Estimates of the total particulate mass of the plumes of Enceladus are important to constrain theories of particle formation and transport at the surface and interior of the satellite. We revisit the calculations of Ingersoll and Ewald (2011), who estimated the particulate mass of the Enceladus plumes from strongly forward scattered light in Cassini ISS images. We model the plume as a combination of spherical particles and irregular aggregates resulting from the coagulation of spherical monomers, the latter of which allows for plumes of lower particulate mass. Though a continuum of solutions are permitted by the model, the best fits to the ISS data consist either of low mass plumes composed entirely of small aggregates or high mass plumes composed of large aggregates and spheres. The high mass plumes can be divided into a population of large aggregates with total particulate mass of 116 +/- 12 X 10^3 kg, and a mixed population of spheres and aggregates consisting of a few large monomers that has a total plume...

  11. Infrared Sensing of Buoyant Surface Plumes

    DEFF Research Database (Denmark)

    Petersen, Ole; Larsen, Torben

    1988-01-01

    This paper is concerned with laboratory experiments on buoyant surface plumes where heat is the source of buoyancy. Temperature distributions were measured at the water surface using infra-red sensing, and inside the waterbody a computer based measurement system was applied. The plume is described...

  12. Exhaust Plume Measurements of the VASIMR VX-200

    Science.gov (United States)

    Longmier, Benjamin; Bering, Edgar, III; Squire, Jared; Glover, Tim; Chang-Diaz, Franklin; Brukardt, Michael

    2008-11-01

    Recent progress is discussed in the development of an advanced RF electric propulsion concept: the Variable Specific Impulse Magnetoplasma Rocket (VASIMR) VX-200 engine, a 200 kW flight-technology prototype. Results from high power Helicon only and Helicon with ICRH experiments are performed on the VX-200 using argon plasma. Recent measurements of axial plasma density and potential profiles, magnetic field-line shaping, charge exchange, and force measurements taken in the plume of the VX-200 exhaust are made within a new 125 cubic meter cryo-pumped vacuum chamber and are presented in the context of RF plasma thruster physics.

  13. Cyclic voltammetry deposition of copper nanostructure on MWCNTs modified pencil graphite electrode: An ultra-sensitive hydrazine sensor

    Energy Technology Data Exchange (ETDEWEB)

    Heydari, Hamid [Faculty of Sciences, Razi University, Kermanshah (Iran, Islamic Republic of); Gholivand, Mohammad B., E-mail: mbgholivand@razi.ac.ir [Faculty of Sciences, Razi University, Kermanshah (Iran, Islamic Republic of); Abdolmaleki, Abbas [Department of Chemistry, Malek Ashtar University of Technology, Tehran (Iran, Islamic Republic of)

    2016-09-01

    In this study, Copper (Cu) nanostructures (CuNS) were electrochemically deposited on a film of multiwall carbon nanotubes (MWCNTs) modified pencil graphite electrode (MWCNTs/PGE) by cyclic voltammetry method to fabricate a CuNS–MWCNTs composite sensor (CuNS–MWCNT/PGE) for hydrazine detection. Scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDX) were used for the characterization of CuNS on the MWCNTs matrix. The composite of CuNS-MWCNTs was characterized with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The preliminary studies showed that the proposed sensor have a synergistic electrocatalytic activity for the oxidation of hydrazine in phosphate buffer. The catalytic currents of square wave voltammetry had a linear correlation with the hydrazine concentration in the range of 0.1 to 800 μM with a low detection limit of 70 nM. Moreover, the amperometric oxidation current exhibited a linear correlation with hydrazine concentration in the concentration range of 50–800 μM with the detection limit of 4.3 μM. The proposed electrode was used for the determination of hydrazine in real samples and the results were promising. Empirical results also indicated that the sensor had good reproducibility, long-term stability, and the response of the sensor to hydrazine was free from interferences. Moreover, the proposed sensor benefits from simple preparation, low cost, outstanding sensitivity, selectivity, and reproducibility for hydrazine determination. - Highlights: • The Copper nanostructures (CuNS) were prepared by cyclic voltammetry deposition. • The CuNS-MWCNT/PGE sensor shows high activity toward hydrazine (N{sub 2}H{sub 4}). • The proposed sensor exhibits a wide linear range (0.1 to 800 μM), low detection limit (70 nM), high sensitivity and stability for hydrazine.

  14. Effect of hydrazine on general corrosion of carbon and low-alloyed steels in pressurized water reactor secondary side water

    Energy Technology Data Exchange (ETDEWEB)

    Järvimäki, Sari [Fortum Ltd, Loviisa Power Plant, Loviisa (Finland); Saario, Timo; Sipilä, Konsta [VTT Technical Research Centre of Finland Ltd., Nuclear Safety, P.O. Box 1000, FIN-02044 VTT (Finland); Bojinov, Martin, E-mail: martin@uctm.edu [Department of Physical Chemistry, University of Chemical Technology and Metallurgy, Kl. Ohridski Blvd, 8, 1756 Sofia (Bulgaria)

    2015-12-15

    Highlights: • The effect of hydrazine on the corrosion of steel in secondary side water investigated by in situ and ex situ techniques. • Oxide grown on steel in 100 ppb hydrazine shows weaker protective properties – higher corrosion rates. • Possible explanation of the accelerating effect of higher concentrations of hydrazine on flow assisted corrosion offered. - Abstract: The effect of hydrazine on corrosion rate of low-alloyed steel (LAS) and carbon steel (CS) was studied by in situ and ex situ techniques under pressurized water reactor secondary side water chemistry conditions at T = 228 °C and pH{sub RT} = 9.2 (adjusted by NH{sub 3}). It is found that hydrazine injection to a maximum level of 5.06 μmol l{sup −1} onto surfaces previously oxidized in ammonia does not affect the corrosion rate of LAS or CS. This is confirmed also by plant measurements at Loviisa NPP. On the other hand, hydrazine at the level of 3.1 μmol l{sup −1} decreases markedly the amount and the size of deposited oxide crystals on LAS and CS surface. In addition, the oxide grown in the presence of 3.1 μmol l{sup −1} hydrazine is somewhat less protective and sustains a higher corrosion rate compared to an oxide film grown without hydrazine. These observations could explain the accelerating effect of higher concentrations of hydrazine found in corrosion studies of LAS and CS.

  15. Modelling oil plumes from subsurface spills.

    Science.gov (United States)

    Lardner, Robin; Zodiatis, George

    2017-07-11

    An oil plume model to simulate the behavior of oil from spills located at any given depth below the sea surface is presented, following major modifications to a plume model developed earlier by Malačič (2001) and drawing on ideas in a paper by Yapa and Zheng (1997). The paper presents improvements in those models and numerical testing of the various parameters in the plume model. The plume model described in this paper is one of the numerous modules of the well-established MEDSLIK oil spill model. The deep blowout scenario of the MEDEXPOL 2013 oil spill modelling exercise, organized by REMPEC, has been applied using the improved oil plume module of the MEDSLIK model and inter-comparison with results having the oil spill source at the sea surface are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Galileo observations of volcanic plumes on Io

    Science.gov (United States)

    Geissler, P.E.; McMillan, M.T.

    2008-01-01

    Io's volcanic plumes erupt in a dazzling variety of sizes, shapes, colors and opacities. In general, the plumes fall into two classes, representing distinct source gas temperatures. Most of the Galileo imaging observations were of the smaller, more numerous Prometheus-type plumes that are produced when hot flows of silicate lava impinge on volatile surface ices of SO2. Few detections were made of the giant, Pele-type plumes that vent high temperature, sulfur-rich gases from the interior of Io; this was partly because of the insensitivity of Galileo's camera to ultraviolet wavelengths. Both gas and dust spout from plumes of each class. Favorably located gas plumes were detected during eclipse, when Io was in Jupiter's shadow. Dense dust columns were imaged in daylight above several Prometheus-type eruptions, reaching heights typically less than 100 km. Comparisons between eclipse observations, sunlit images, and the record of surface changes show that these optically thick dust columns are much smaller in stature than the corresponding gas plumes but are adequate to produce the observed surface deposits. Mie scattering calculations suggest that these conspicuous dust plumes are made up of coarse grained “ash” particles with radii on the order of 100 nm, and total masses on the order of 106 kg per plume. Long exposure images of Thor in sunlight show a faint outer envelope apparently populated by particles small enough to be carried along with the gas flow, perhaps formed by condensation of sulfurous “snowflakes” as suggested by the plasma instrumentation aboard Galileo as it flew through Thor's plume [Frank, L.A., Paterson, W.R., 2002. J. Geophys. Res. (Space Phys.) 107, doi:10.1029/2002JA009240. 31-1]. If so, the total mass of these fine, nearly invisible particles may be comparable to the mass of the gas, and could account for much of Io's rapid resurfacing.

  17. Understanding CO2 capture mechanisms in aqueous hydrazine via combined NMR and first-principles studies.

    Science.gov (United States)

    Lee, Byeongno; Stowe, Haley M; Lee, Kyu Hyung; Hur, Nam Hwi; Hwang, Son-Jong; Paek, Eunsu; Hwang, Gyeong S

    2017-09-13

    Aqueous amines are currently the most promising solution for large-scale CO2 capture from industrial sources. However, molecular design and optimization of amine-based solvents have proceeded slowly due to a lack of understanding of the underlying reaction mechanisms. Unique and unexpected reaction mechanisms involved in CO2 absorption into aqueous hydrazine are identified using (1)H, (13)C, and (15)N NMR spectroscopy combined with first-principles quantum-mechanical simulations. We find production of both hydrazine mono-carbamate (NH2-NH-COO(-)) and hydrazine di-carbamate ((-)OOC-NH-NH-COO(-)), with the latter becoming more populated with increasing CO2 loading. Exchange NMR spectroscopy also demonstrates that the reaction products are in dynamic equilibrium under ambient conditions due to CO2 exchange between mono-carbamate and di-carbamate as well as fast proton transfer between un-protonated free hydrazine and mono-carbamate. The exchange rate rises steeply at high CO2 loadings, enhancing CO2 release, which appears to be a unique property of hydrazine in aqueous solution. The underlying mechanisms of these processes are further evaluated using quantum mechanical calculations. We also analyze and discuss reversible precipitation of carbamate and conversion of bicarbonate to carbamates. The comprehensive mechanistic study provides useful guidance for optimal design of amine-based solvents and processes to reduce the cost of carbon capture. Moreover, this work demonstrates the value of a combined experimental and computational approach for exploring the complex reaction dynamics of CO2 in aqueous amines.

  18. Morpho-functional Blood Changes Under the Influence of Hydrazine and Correction with “Salsokollin” Drug

    Directory of Open Access Journals (Sweden)

    Marat R. Khanturin

    2012-09-01

    Full Text Available Hydrazine derivatives are used in different areas: airspace industry, healthcare, laboratory-diagnostic activity, that’s why the environment is subjected to contamination by hydrazines. For Kazakhstan, which houses the "Baikonur" Cosmodrome, the problem of environmental pollution by rocket fuel and its components is a burning issue nowadays. This article deals with the impacts by industrial hydrazines on biochemical data of the blood and its correction with the “Salsokollin” Drug. The samples of bilirubin, the whole protein, urea, creatinine, cholesterol, glucose, aminotransferase a-amylases, α-amylase were taken. The thymol test was carried out.

  19. Underexpanded Supersonic Plume Surface Interactions: Applications for Spacecraft Landings on Planetary Bodies

    Science.gov (United States)

    Mehta, M.; Sengupta, A.; Renno, N. O.; Norman, J. W.; Gulick, D. S.

    2011-01-01

    Numerical and experimental investigations of both far-field and near-field supersonic steady jet interactions with a flat surface at various atmospheric pressures are presented in this paper. These studies were done in assessing the landing hazards of both the NASA Mars Science Laboratory and Phoenix Mars spacecrafts. Temporal and spatial ground pressure measurements in conjunction with numerical solutions at altitudes of approx.35 nozzle exit diameters and jet expansion ratios (e) between 0.02 and 100 are used. Data from steady nitrogen jets are compared to both pulsed jets and rocket exhaust plumes at Mach approx.5. Due to engine cycling, overpressures and the plate shock dynamics are different between pulsed and steady supersonic impinging jets. In contrast to highly over-expanded (e plumes, results show that there is a relative ground pressure load maximum for moderately underexpanded (e approx.2-5) jets which demonstrate a long collimated plume shock structure. For plumes with e much >5 (lunar atmospheric regime), the ground pressure is minimal due to the development of a highly expansive shock structure. We show this is dependent on the stability of the plate shock, the length of the supersonic core and plume decay due to shear layer instability which are all a function of the jet expansion ratio. Asymmetry and large gradients in the spatial ground pressure profile and large transient overpressures are predominantly linked to the dynamics of the plate shock. More importantly, this study shows that thruster plumes exhausting into martian environments possess the largest surface pressure loads and can occur at high spacecraft altitudes in contrast to the jet interactions at terrestrial and lunar atmospheres. Theoretical and analytical results also show that subscale supersonic cold gas jets adequately simulate the flow field and loads due to rocket plume impingement provided important scaling parameters are in agreement. These studies indicate the critical

  20. Simultaneous determination of hydrazine and phenyl hydrazine using 4′-(4-carboxyphenyl)-2,2′:6′,2″ terpyridine diacetonitrile triphenylphosphine ruthenium(II) tetrafluoroborate complex functionalized multiwalled carbon nanotubes modified electrode

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, Ida, E-mail: idatiwari_2001@rediffmail.com [Department of Chemistry (Center of Advanced Study), Faculty of Science, Banaras Hindu University, Varanasi (India); Gupta, Mandakini; Sinha, Preeti [Department of Chemistry (Center of Advanced Study), Faculty of Science, Banaras Hindu University, Varanasi (India); Banks, Craig E. [Faculty of Science and Engineering, School of Science and the Environment, Division of Chemistry and Environmental Science, Manchester Metropolitan University, Chester Street, Manchester M1 5GD (United Kingdom)

    2014-12-15

    Highlights: • A nanocomposite of ruthenium(II) terpyridine, triphenylphosphine based complex and multiwalled carbon nanotubes have been used first time for simultaneous detection of hydrazine and phenyl hydrazine. • The detection limit reported is lower as compared to other reported works. • The paper also focuses towards effect of ligand variation attached to ruthenium(II) terpyridine based complexes complex for the hydrazine and phenyl hydrazine detection. • Nanocomposite does not involve any biological entity hence high stability. - Abstract: A nanocomposite based on the incorporation of the complex 4′-(4-carboxyphenyl)-2,2′:6′,2″ terpyridine triphenylphosphine diacetonitrile ruthenium(II) tetrafluoroborate with multiwalled carbon nanotubes and ionomer supported upon a glassy carbon electrode substrate is reported and characterized with scanning electron microscopy, transmission electron microscopy and infrared spectroscopy. The electrochemical behavior and stability of the composite electrode was investigated via cyclic voltammetry. The modified electrode exhibits an electro-catalytic activity towards the oxidation of both hydrazine and phenyl hydrazine in 0.1 M phosphate buffer solution (PBS, pH 7.4). The oxidation of hydrazine and phenyl hydrazine occurs at 0.81 V and 0.32 V with limit of detection found to be 3.7 × 10{sup −7} M and 1.15 × 10{sup −7} M and having a linear range from 5 × 10{sup −6} M to 6.5 × 10{sup −3} M, and 5 × 10{sup −6} M to 0.2 × 10{sup −3} M, respectively.

  1. Merging Thermal Plumes in the Indoor Environment

    DEFF Research Database (Denmark)

    Bjørn, Erik; Nielsen, Peter V.

    This experimental work deals with the basic problem of merging thermal plumes from heat sources situated in the vicinity of each other. No studies have been made yet of how close two heat sources must be to each other, before they can be considered as a single source with a cumulative heat effect......, and how far apart they must be to be considered separate. Also, it is not known how the flow field behaves in the intermediate fase, where the plumes are neither completely joined nor completely separate. A possible, very simple, solution of the velocity distribution between two plumes is to assume...

  2. Kinetic Study of the Electro-Catalytic Oxidation of Hydrazine on Cobalt Hydroxide Modified Glassy Carbon Electrode

    Institute of Scientific and Technical Information of China (English)

    HASANZADEH,Mohammad; KARIM-NEZHAD,Ghasem; SHADJOU,Nasrin; KHALILZADEH,Balal; SAGHATFOROUSH,Lotali; ERSHAD,Sohrab; KAZEMAN,Isa

    2009-01-01

    Electrocatalytic oxidation of hydrazine was investigated on a cobalt hydroxide modified glassy carbon (CHM-GC) electrode in alkaline solution.The process of oxidation involved and its kinetics were established by using cyclic voltammetry,chronoamperometry techniques as well as steady state polarization measurements.In cyclic voltammetry (CV) studies,in the presence of hydrazine the peak current increase of the oxidation of cobalt hydroxide is followed by a decrease in the corresponding cathodic current.This indicates that hydrazine is oxidized on the redox mediator that is immobilized on the electrode surface via an electrocatalytic mechanism.A mechanism based on the electrochemical generation of Co(IV) active sites and their subsequent consumption by the hydrazine in question was also investigated.

  3. Experimental determination of plume properties in full-scale hydrogen-oxygen rockets

    Science.gov (United States)

    Brown, D. G.; Limbaugh, C. C.; Zaccardi, V. A.; Eskridge, R.

    1989-01-01

    An IR emission/absorption technique for determining radial profiles of static temperature and species partial pressure for cylindrically symmetric combustion gases typical of the effluent of turbine engines and liquid-propellant rockets is described. In the technique, the IR plume radiance and absorption is measured using a 1 x 256-element platinum silicide detector array which is filtered to obtain plume emission measurements in the H2O band near 3.0 microns. A minicomputer is employed to control data acquisition and reduction.

  4. New practical synthesis of indazoles via condensation of o-fluorobenzaldehydes and their O-methyloximes with hydrazine.

    Science.gov (United States)

    Lukin, Kirill; Hsu, Margaret C; Fernando, Dilinie; Leanna, M Robert

    2006-10-13

    The reaction of o-fluorobenzaldehydes and their O-methyloximes with hydrazine has been developed as a new practical synthesis of indazoles. Utilization of the methyloxime derivatives of benzaldehydes (in the form of the major E-isomers) in this condensation effectively eliminated a competitive Wolf-Kishner reduction to fluorotoluenes, which was observed in the direct preparations of indazoles from aldehydes. Reaction of Z-isomers of methyloximes with hydrazine resulted in the formation of 3-aminoindazoles via a benzonitrile intermediate.

  5. Advanced high pressure engine study for mixed-mode vehicle applications

    Science.gov (United States)

    Luscher, W. P.; Mellish, J. A.

    1977-01-01

    High pressure liquid rocket engine design, performance, weight, envelope, and operational characteristics were evaluated for a variety of candidate engines for use in mixed-mode, single-stage-to-orbit applications. Propellant property and performance data were obtained for candidate Mode 1 fuels which included: RP-1, RJ-5, hydrazine, monomethyl-hydrazine, and methane. The common oxidizer was liquid oxygen. Oxygen, the candidate Mode 1 fuels, and hydrogen were evaluated as thrust chamber coolants. Oxygen, methane, and hydrogen were found to be the most viable cooling candidates. Water, lithium, and sodium-potassium were also evaluated as auxiliary coolant systems. Water proved to be the best of these, but the system was heavier than those systems which cooled with the engine propellants. Engine weight and envelope parametric data were established for candidate Mode 1, Mode 2, and dual-fuel engines. Delivered engine performance data were also calculated for all candidate Mode 1 and dual-fuel engines.

  6. Assessment of analytical techniques for predicting solid propellant exhaust plumes and plume impingement environments

    Science.gov (United States)

    Tevepaugh, J. A.; Smith, S. D.; Penny, M. M.

    1977-01-01

    An analysis of experimental nozzle, exhaust plume, and exhaust plume impingement data is presented. The data were obtained for subscale solid propellant motors with propellant Al loadings of 2, 10 and 15% exhausting to simulated altitudes of 50,000, 100,000 and 112,000 ft. Analytical predictions were made using a fully coupled two-phase method of characteristics numerical solution and a technique for defining thermal and pressure environments experienced by bodies immersed in two-phase exhaust plumes.

  7. Sensitivity of air quality simulation to smoke plume rise

    Science.gov (United States)

    Yongqiang Liu; Gary Achtemeier; Scott Goodrick

    2008-01-01

    Plume rise is the height smoke plumes can reach. This information is needed by air quality models such as the Community Multiscale Air Quality (CMAQ) model to simulate physical and chemical processes of point-source fire emissions. This study seeks to understand the importance of plume rise to CMAQ air quality simulation of prescribed burning to plume rise. CMAQ...

  8. Ascorbic Acid Assisted Synthesis of Cobalt Oxide Nanostructures, Their Electrochemical Sensing Application for the Sensitive Determination of Hydrazine

    Science.gov (United States)

    Tahira, Aneela; Nafady, Ayman; Baloach, Quarratulain; Sirajuddin; Sherazi, Syed Tufail Hussain; Shaikh, Tayyaba; Arain, Munazza; Willander, Magnus; Ibupoto, Zafar Hussain

    2016-07-01

    This study describes, the synthesis of cobalt oxide nanostructures using ascorbic acid as a growth directing agent by the hydrothermal method. Ascorbic acid is used for the first time for the synthesis of cobalt oxide nanostructures and a unique morphology is prepared in the present study. The cobalt oxide nanostructures were characterized by scanning electron microcopy, x-ray diffraction, and x-ray photoelectron spectroscopy techniques. These analytical techniques demonstrated well defined morphology, good crystalline quality, and high purity of as prepared cobalt oxide nanostructures. The glassy carbon electrode was modified with cobalt oxide nanostructures for the development of a sensitive and selective electrochemical hydrazine sensor. The developed hydrazine sensor exhibits a linear range of 2-24 μM. The sensitivity and limit of detection of presented hydrazine sensors are 12,734 μA/mM/cm2 and 0.1 μM respectively. The developed hydrazine sensor is highly selective, stable, and reproducible. The proposed sensor is successfully applied for the detection of hydrazine from different water samples. The present study provides the development of an alternative tool for the reliable monitoring of hydrazine from environmental and biological samples.

  9. Characteristics of the Great Whale River plume

    Science.gov (United States)

    Ingram, R. Grant

    1981-03-01

    Observations of the motion field and dilution effects associated with the plume of Great Whale River in Hudson Bay are presented for both open water and ice-covered conditions. In the summer months a distinct plume of about 100 km2 in area is formed offshore which is characterized by a 1-2 m thickness and large velocities directed away from the river mouth in contrast to slower currents parallel to the shore in the ambient waters underneath. Surface drifter results suggest that the outer boundary of plume may be a zone of frontal convergence. Under ice-covered conditions the plume was significantly thicker and extended much farther offshore in spite of a marked reduction in river runoff at this time.

  10. Mantle plumes: Why the current skepticism?

    Institute of Scientific and Technical Information of China (English)

    Gillian R. Foulger

    2005-01-01

    The present reappraisal of the mantle plume hypothesis is perhaps the most exciting current debate in Earth science. Nevertheless, the fundamental reasons for why it has arisen are often not well understood. They are that 1) many observations do not agree with the predictions of the original model, 2) it is possible that convection of the sort required to generate thermal plumes in the Earth's mantle does not occur, 3) so many variants of the original model have been invoked to accommodate conflicting data that the plume hypthesis is in practice no longer testable, and 4) alternative models are viable, though these have been largely neglected by researchers. Regardless of the final outcome, the present vigorous debate is to be welcomed since it is likely to stimulate new discoveries in a way that unquestioning acceptance of the conventional plume model will not.

  11. Hydroxyl Tagging Velocimetry for Rocket Plumes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — To address the need for non-intrusive sensors for rocket plume properties, we propose a laser-based velocity diagnostic that does not require seeding, works in high...

  12. Novel plume deflection concept testing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed effort will explore the feasibility and effectiveness of utilizing an electrically driven thermal shield for use as part of rocket plume deflectors. To...

  13. Plume Ascent Tracker: Interactive Matlab software for analysis of ascending plumes in image data

    Science.gov (United States)

    Valade, S. A.; Harris, A. J. L.; Cerminara, M.

    2014-05-01

    This paper presents Matlab-based software designed to track and analyze an ascending plume as it rises above its source, in image data. It reads data recorded in various formats (video files, image files, or web-camera image streams), and at various wavelengths (infrared, visible, or ultra-violet). Using a set of filters which can be set interactively, the plume is first isolated from its background. A user-friendly interface then allows tracking of plume ascent and various parameters that characterize plume evolution during emission and ascent. These include records of plume height, velocity, acceleration, shape, volume, ash (fine-particle) loading, spreading rate, entrainment coefficient and inclination angle, as well as axial and radial profiles for radius and temperature (if data are radiometric). Image transformations (dilatation, rotation, resampling) can be performed to create new images with a vent-centered metric coordinate system. Applications may interest both plume observers (monitoring agencies) and modelers. For the first group, the software is capable of providing quantitative assessments of plume characteristics from image data, for post-event analysis or in near real-time analysis. For the second group, extracted data can serve as benchmarks for plume ascent models, and as inputs for cloud dispersal models. We here describe the software's tracking methodology and main graphical interfaces, using thermal infrared image data of an ascending volcanic ash plume at Santiaguito volcano.

  14. Fire analog: a comparison between fire plumes and energy center cooling tower plumes

    Energy Technology Data Exchange (ETDEWEB)

    Orgill, M.M.

    1977-10-01

    Thermal plumes or convection columns associated with large fires are compared to thermal plumes from cooling towers and proposed energy centers to evaluate the fire analog concept. Energy release rates of mass fires are generally larger than for single or small groups of cooling towers but are comparable to proposed large energy centers. However, significant physical differences exist between cooling tower plumes and fire plumes. Cooling tower plumes are generally dominated by ambient wind, stability and turbulence conditions. Fire plumes, depending on burning rates and other factors, can transform into convective columns which may cause the fire behavior to become more violent. This transformation can cause strong inflow winds and updrafts, turbulence and concentrated vortices. Intense convective columns may interact with ambient winds to create significant downwind effects such as wakes and Karman vortex streets. These characteristics have not been observed with cooling tower plumes to date. The differences in physical characteristics between cooling tower and fire plumes makes the fire analog concept very questionable even though the approximate energy requirements appear to be satisfied in case of large energy centers. Additional research is suggested in studying the upper-level plume characteristics of small experimental fires so this information can be correlated with similar data from cooling towers. Numerical simulation of fires and proposed multiple cooling tower systems could also provide comparative data.

  15. Near-glacier surveying of a subglacial discharge plume: Implications for plume parameterizations

    Science.gov (United States)

    Jackson, R. H.; Shroyer, E. L.; Nash, J. D.; Sutherland, D. A.; Carroll, D.; Fried, M. J.; Catania, G. A.; Bartholomaus, T. C.; Stearns, L. A.

    2017-07-01

    At tidewater glaciers, plume dynamics affect submarine melting, fjord circulation, and the mixing of meltwater. Models often rely on buoyant plume theory to parameterize plumes and submarine melting; however, these parameterizations are largely untested due to a dearth of near-glacier measurements. Here we present a high-resolution ocean survey by ship and remotely operated boat near the terminus of Kangerlussuup Sermia in west Greenland. These novel observations reveal the 3-D structure and transport of a near-surface plume, originating at a large undercut conduit in the glacier terminus, that is inconsistent with axisymmetric plume theory, the most common representation of plumes in ocean-glacier models. Instead, the observations suggest a wider upwelling plume—a "truncated" line plume of ˜200 m width—with higher entrainment and plume-driven melt compared to the typical axisymmetric representation. Our results highlight the importance of a subglacial outlet's geometry in controlling plume dynamics, with implications for parameterizing the exchange flow and submarine melt in glacial fjord models.

  16. STRATAFORM Plume Study: Analysis and Modeling

    Science.gov (United States)

    1999-09-30

    of settling is explained by the variation of plume speed, rather than by variations in settling velocity (Hill et al., submitted). Floculation is an...mouth. However, the fraction of floculated sediment does not vary as much as expected with changes in forcing conditions. There do appear to be large...differences in the floculation rate between the extreme flood conditions of 1997 and the more moderate floods of 1998. The detailed examination of plume

  17. Rocket plume tomography of combustion species

    OpenAIRE

    2001-01-01

    Interest in accurate detection and targeting of aggressor missiles has received considerable interest with the national priority of developing a missile defense system. Understanding the thermal signatures of the exhaust plumes of such missiles is key to accomplishing that mission. Before signature models can be precisely developed for specific rockets, the radiation of the molecular or combustion species within those plumes must be accurately predicted. A combination translation / rotation s...

  18. Cretaceous Arctic magmatism: Slab vs. plume? Or slab and plume?

    Science.gov (United States)

    Gottlieb, E. S.; Miller, E. L.; Andronikov, A. V.; Brumley, K.; Mayer, L. A.; Mukasa, S. B.

    2010-12-01

    Tectonic models for the Cretaceous paleogeographic evolution of the Arctic Ocean and its adjacent landmasses propose that rifting in the Amerasia Basin (AB) began in Jura-Cretaceous time, accompanied by the development of the High Arctic Large Igneous Province (HALIP). During the same timespan, deformation and slab-related magmatism, followed by intra-arc rifting, took place along the Pacific side of what was to become the Arctic Ocean. A compilation and comparison of the ages, characteristics and space-time variation of circum-Arctic magmatism allows for a better understanding of the role of Pacific margin versus Arctic-Atlantic plate tectonics and the role of plume-related magmatism in the origin of the Arctic Ocean. In Jura-Cretaceous time, an arc built upon older terranes overthrust the Arctic continental margins of North America and Eurasia, shedding debris into foreland basins in the Brooks Range, Alaska, across Chukotka, Russia, to the Lena Delta and New Siberian Islands region of the Russian Arctic. These syn-tectonic sediments have some common sources (e.g., ~250-300 Ma magmatic rocks) as determined by U-Pb detrital zircon geochronology. They are as young as Valanginian-Berriasian (~136 Ma, Gradstein et al., 2004) and place a lower limit on the age of formation of the AB. Subsequent intrusions of granitoid plutons, inferred to be ultimately slab-retreat related, form a belt along the far eastern Russian Arctic continental margin onto Seward Peninsula and have yielded a continuous succession of zircon U-Pb ages from ~137-95 Ma (n=28) and a younger suite ~91-82 Ma (n=16). All plutons dated were intruded in an extensional tectonic setting based on their relations to wall-rock deformation. Regional distribution of ages shows a southward migration of the locus of magmatism during Cretaceous time. Basaltic lavas as old as 130 Ma and as young as 80 Ma (40Ar/39Ar)) erupted across the Canadian Arctic Islands, Svalbard and Franz Josef Land and are associated with

  19. Self-regulating heater application to Shuttle/Centaur hydrazine fuel line thermal control

    Science.gov (United States)

    Unkrich, David B.

    1987-01-01

    The Shuttle/Centaur high energy upper stage vehicle thermal environments were more severe than previous Centaur vehicle thermal environments, creating need for a new hydrazine fuel line thermal control technique. Constant power heaters did not satisfy power dissipation requirements, because the power required to maintain fuel line thermal control during cold conditions exceeded the maximum power allowable during hot conditions. Therefore, a Raychem Thermolimit self-regulating heater was selected for this application, and was attached to the hydrazine fuel line with Kapton and aluminum foil tapes. Fuel line/heater thermal modeling and subsequent thermal vacuum chamber testing simulated heater thermal performance during all worst-case Shuttle/Centaur thermal environmental conditions. Fuel line temperatures were maintained between the 4C to 71C limits during all analytical and test cases. Finally, the thermal model predictions were correlated with the test data, thereby ensuring that the model would provide satisfactory predictions for future missions and/or vehicles.

  20. 2-(Hetero(aryl)methylene)hydrazine-1-carbothioamides as potent urease inhibitors.

    Science.gov (United States)

    Saeed, Aamer; Imran, Aqeel; Channar, Pervaiz A; Shahid, Mohammad; Mahmood, Wajahat; Iqbal, Jamshed

    2015-02-01

    A small series of 2-(hetero(aryl)methylene) hydrazine-1-carbothioamides including two aryl derivatives was synthesized and tested for their inhibitory activity against urease. Compound (E)-2-(Furan-2-ylmethylene) hydrazine-1-carbothioamide (3f), having a furan ring, was the most potent inhibitor of urease with an IC50 value of 0.58 μM. Molecular modeling was carried out through docking the designed compounds into the urease binding site to predict whether these derivatives have analogous binding mode to the urease inhibitors. The study revealed that all of the tested compounds bind with both metal atoms at the active site of the enzyme. The aromatic ring of the compounds forms ionic interactions with the residues, Ala(440), Asp(494), Ala(636), and Met(637).

  1. Towards Safer Rocket Fuels: Hypergolic Imidazolylidene-Borane Compounds as Replacements for Hydrazine Derivatives.

    Science.gov (United States)

    Huang, Shi; Qi, Xiujuan; Liu, Tianlin; Wang, Kangcai; Zhang, Wenquan; Li, Jianlin; Zhang, Qinghua

    2016-07-11

    Currently, toxic and volatile hydrazine derivatives are still the main fuel choices for liquid bipropellants, especially in some traditional rocket propulsion systems. Therefore, the search for safer hypergolic fuels as replacements for hydrazine derivatives has been one of the most challenging tasks. In this study, six imidazolylidene-borane compounds with zwitterionic structure have been synthesized and characterized, and their hypergolic reactivity has been studied. As expected, these compounds exhibited fast spontaneous combustion upon contact with white fuming nitric acid (WFNA). Among them, compound 5 showed excellent integrated properties including wide liquid operating range (-70-160 °C), superior loading density (0.99 g cm(-3) ), ultrafast ignition delay times with WFNA (15 ms), and high specific impulse (303.5 s), suggesting promising application potential as safer hypergolic fuels in liquid bipropellant formulations.

  2. Formation of raspberry like cobalt particles with hydrazine reduction in a polyol route

    Science.gov (United States)

    Khe, Cheng Seong; Aziz, Azizan; Lockman, Zainovia; Rajalingam, Sokkalingam; Merican, Zulkifli; Vasant, Pandian

    2016-11-01

    This work describes the effect of hydrazine hydrate on the formation of the raspberry-like morphology of the cobalt nanomaterials in a polyol route. In the synthesis, the molar ratio of N2H4 to Co2+was varied from 2.5 to 10. At the beginning with low molar ratio, spherical microspheres were formed. When the molar ratio was increased to 5 and above, final morphology of the cobalt nanomaterials became raspberry-like. This might be attributed to the absorption of the hydrazine complex of cobalt nanoparticles at certain facets during their growth stage and later self-assembled into the raspberry shaped microparticles. The plausible formation mechanism were proposed.

  3. Microwave-assisted synthesis of carbon-supported carbides catalysts for hydrous hydrazine decomposition

    Science.gov (United States)

    Mnatsakanyan, Raman; Zhurnachyan, Alina R.; Matyshak, Valery A.; Manukyan, Khachatur V.; Mukasyan, Alexander S.

    2016-09-01

    Microwave-assisted synthesis of carbon-supported Mo2C and WC nanomaterials was studied. Two different routes were utilized to prepare MoO3 (WO3) - C precursors that were then subjected to microwave irradiation in an inert atmosphere. The effect of synthesis conditions, such as irradiation time and gas environment, was investigated. The structure and formation mechanism of the carbide phases were explored. As-synthesized nanomaterials exhibited catalytic activity for hydrous hydrazine (N2H4·H2O) decomposition at 30-70 °C. It was shown that the catalyst activity significantly increases if microwave irradiation is applied during the decomposition process. Such conditions permit complete conversion of hydrazine to ammonia and nitrogen within minutes. This effect can be attributed to the unique nanostructure of the catalysts that includes microwave absorbing carbon and active carbide constituents.

  4. In situ measurements of HO{sub x} in super- and subsonic aircraft exhaust plumes

    Energy Technology Data Exchange (ETDEWEB)

    Hanisco, T.F.; Wennberg, P.O.; Cohen, R.C.; Anderson, J.G. [Harvard Univ., Cambridge, MA (United States). Dept. of Chemistry; Fahey, D.W.; Keim, E.R.; Gao, R.S.; Wamsley, R.C.; Donnelly, S.G.; Del Negro, L.A. [National Oceanic and Atmospheric Administration, Boulder, CO (United States). Aeronomy Lab.; and others

    1997-12-31

    Concentrations of HO{sub x} (OH and HO{sub 2}) have been obtained in the exhaust plumes of an Air France Concorde and a NASA ER-2 in the lower stratosphere and the NASA DC-8 in the upper troposphere using instruments aboard the NASA ER-2. These fast-time response in situ measurements are used in conjunction with simultaneous in situ measurements of other key exhaust species (NO, NO{sub 2}, NO{sub y}, H{sub 2}O, and CO) to analyze the emissions of HO{sub x} from each aircraft under a variety of conditions. The data are used to establish a general description of gas phase plume chemistry that is easily implemented in a photochemical model. This model is used to determine the amount of HO{sub x} emitted from the engines and the gas phase oxidation rates of nitrogen and sulfur species in the exhaust plumes. (author) 10 refs.

  5. The Effects of Hydrazines and Related Compounds on Calcium Calmodulin Regulated Synaptic Processes

    Science.gov (United States)

    1983-07-01

    4F -631 0 1984 E IS. KEY WORDS (Continue on reverse side if necessary and identify by block nunmber) Calmodulin, protein kinase, adenylate cyclase...hydrazines, organophosphates, C) calcium, synaptic processes, protein phosphorylation. 20. BSTRACT (Continue an reverse side it necessary mid Identify...Date Entered) %. % V -*> ~ * - Unclassified SECURITY CLASIFICATION OF THIS PAGE(Vhun Dots tn er@Q 20. A BWT&CT continued, nmembrane fractions and

  6. Dimethyl hydrazine-1,2-dicarboxylate–triphenylphosphine oxide (1/1

    Directory of Open Access Journals (Sweden)

    Bogdan Doboszewski

    2011-07-01

    Full Text Available In the crystal structure of the title compound, C4H8N2O4·C18H15OP, two triphenylphosphine oxide molecules and two dimethyl hydrazine-1,2-dicarboxylate molecules are connected via N—H...O hydrogen bonds of moderate strength and are related via a twofold rotational axis. Weak Car—H... O contacts strengthen the crystal structure.

  7. Preparation of Peptide p-Nitroanilides using an Aryl Hydrazine Solid Support

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Y; Welsh, K; Mitchell, A R; Camarero, J A

    2004-08-05

    Peptide p-nitroanilides are useful compounds for studying protease activity, however the poor nucleophilicity of p-nitroaniline makes their preparation difficult. We describe a new efficient approach for the Fmoc-based synthesis of peptide p-nitroanilides using an aryl hydrazine resin. Mild oxidation of the peptide hydrazide resin yields a highly reactive acyl diazene, which efficiently reacts with weak nucleophiles. We have prepared several peptide p-nitroanilides, including substrates for the Lethal Factor protease from B. anthracis.

  8. Nanostructured SnO2 encapsulated guar-gum hybrid nanocomposites for electrocatalytic determination of hydrazine.

    Science.gov (United States)

    Malik, Priya; Srivastava, Manish; Verma, Ranjana; Kumar, Manish; Kumar, D; Singh, Jay

    2016-01-01

    The present article deals with synthesis of sol-gel derived tin dioxide (SnO2) nanoparticles encapsulated in to guar gum (GG) biopolymer as the organic-inorganic hybrid materials for the determination of hydrazine. The organic-inorganic hybrid combines the perfunctory strength offered by the inorganic SnO2 nanoparticles with flexible binding sites provided by the organic biopolymer (GG) solution by the ultrasonication. The phase identification, crystalline size, surface morphology and optical properties of prepared SnO2 and SnO2-GG nanocomposites has been investigated through FT-IR, XRD, SEM, AFM, TEM, UV-Vis, and PL techniques. The colloidal solution of SnO2 and GG is electrophoretically deposited (EPD) onto the indium tin-oxide (ITO) glass substrate and studied for the electrooxidation of hydrazine. Under the optimized experimental conditions, the linearity between the current response and the hydrazine concentration has been obtained in the range of 2-22 mM, with a low detection limit of 2.76 mM and a high sensitivity of 5.72 μA cm(-2). Based on the linear increase in amperometric current, a sensitive hydrazine electrochemical sensor is constructed. The proposed SnO2-GG/ITO electrode shows a good response time (35s), reproducibility, and long-term stability. The obtained results suggest that SnO2-GG nanocomposites electrode provides a favorable sensing platform for the electrochemical studies. In addition, the cyclic voltammetry (CV) studies are used to evaluate the kinetic parameters.

  9. Design, Synthesis and Biological Activities of Novel Benzoyl Hydrazines Containing Pyrazole

    Institute of Scientific and Technical Information of China (English)

    闫涛; 于淑晶; 刘鹏飞; 刘卓; 王宝雷; 熊丽霞; 李正名

    2012-01-01

    In search of environmentally benign compounds with high biological activity, low toxicity and low resistance, 8 novel benzoyl hydrazines containing pyrazole were designed and synthesized. All compounds were characterized by I H NMR spectra and HRMS. The preliminary results of biological activity assessment indicated that most of title compounds exhibited certain insecticidal activities against M),thimna separata Walker at 200 mg L-1 but excellent fungicidal activities against six fungus at 50 mg L-1, which were better than the control.

  10. Dose response of hydrazine - Deproteinated tooth enamel under blue light stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Yuece, Ulkue Rabia, E-mail: ulkuyuce@hotmail.co [Ankara University, Faculty of Engineering, Department of Engineering Physics, 06100, Tandogan - Ankara (Turkey); Meric, Niyazi, E-mail: meric@ankara.edu.t [Ankara University, Faculty of Engineering, Department of Engineering Physics, 06100, Tandogan - Ankara (Turkey); Atakol, Orhan, E-mail: atakol@science.ankara.edu.t [Ankara University, Science Faculty, Department of Chemistry, 06100, Tandogan - Ankara (Turkey); Yasar, Fusun, E-mail: ab121310@adalet.gov.t [Council of Forensic Medicine, Ankara Branch, Ankara (Turkey)

    2010-08-15

    The beta dose response and Optically Stimulated Luminescence (OSL) signal stability characteristics of human tooth enamel deproteinated by hydrazine reagent under blue photon stimulation are reported. Removal of the protein organic component of tooth enamel resulted in a higher OSL sensitivity and slower fading of OSL signals. The effect of chemical sample preparation on the enamel sample sensitivity is discussed and further steps to make this deproteinization treatment suitable for in vitro dose reconstruction studies are suggested.

  11. Highly Sensitive Hydrazine Chemical Sensor Based on CNT-PdPt Nanocomposites

    Directory of Open Access Journals (Sweden)

    Sung Phil Kim

    2015-01-01

    Full Text Available Bimetallic PdPt nanoparticles were prepared using the chemical reduction method. The PdPt nanoparticles were successfully deposited on thiolated carbon nanotubes (CNTs to form a CNT-PdPt nanocomposite as an electron mediator for the fabrication of a hydrazine sensor. The PdPt nanoparticles had an average particle size of 2.3 nm and were well dispersed on the surfaces of the CNTs in the prepared CNT-PdPt nanocomposite, as demonstrated using transmission electron microscopy (TEM, energy dispersive X-ray spectroscopy (EDX, and X-ray diffraction (XRD. Based on X-ray photoelectron spectroscopy (XPS results, the estimated proportions of Pd and Pt in the CNT-PdPt nanocomposite were approximately 3.0% and 3.2%, respectively. A fabricated chemical sensor based on CNT-PdPt was found to exhibit better amperometric activity with respect to the hydrazine oxidation reaction than CNT-Pd, CNT-Pt, and commercial Pd/C and Pt/C catalysts. This sensor exhibited a linear range of 0.55–1,200 μM and a detection limit of 0.28 μM (S/N = 3 with a fast response time (within 5 s. Furthermore, the sensor could be used repeatedly for the consecutive detection of hydrazine with good reusability and storage stability. These properties demonstrate that the CNT-PdPt nanocomposite is a promising electron mediator for the fabrication of amperometric hydrazine sensors.

  12. Reactivity of 4-tert-Butyldimethylsiloxy-1,2,3,6-tetrahydropyridines with Hydrazines

    Directory of Open Access Journals (Sweden)

    Manuel Medarde

    2006-11-01

    Full Text Available The reactivity of 6-(nitrophenyl or trimethoxyphenyl-4-tert-butyldimethyl- siloxy-1,2,3,6-tetrahydropyridine derivatives with hydrazines under acid conditions is described. The structure of the products isolated − hydrazones, pyrazolines or pyridazinones − depended on the conditions used. In addition, a systematic study of the reaction outcomes was carried out by introducing variations on the substituents of the tetrahydropyridine ring.

  13. Study on the Reaction Between Methyl Hydrazine and Formaldehyde in Nitric Acid Medium

    Institute of Scientific and Technical Information of China (English)

    LI; Chuan-bo; CAO; Zhi; BIAN; Xiao-yan; XIAN; Liang; YAN; Tai-hong; ZHENG; Wei-fang

    2012-01-01

    <正>To make sure whether the reaction between formaldehyde and methyl hydrazine (MMH) could happen in dilute nitric acid solution, the condensation reaction between the two ones was investigated at 16 ℃. The reaction was slow and it took over 5 hours to reach the balance and the solution turned yellow at last. The maximum absorption peaks of the product existed at 340 nm and 400-450 nm, respectively.

  14. (E)-1-Benzyl-idene-2,2-diphenyl-hydrazine.

    Science.gov (United States)

    Mendoza, Angel; Meléndrez-Luevano, Ruth; Cabrera-Vivas, Blanca M; Lozano-Márquez, Claudia D; Carranza, Vladimir

    2012-02-01

    The asymmetric unit of the title compound, C(19)H(16)N(2), contains two independent mol-ecules, both of which show an E configuration with respect to the C=N bond. The dihedral angles between the phenyl rings bonded to the hydrazine group are 81.00 (10) and 88.34 (8)° in the two mol-ecules. Inter-molecular C-H⋯π inter-actions are observed in the crystal structure.

  15. Effect of gaseous and solid simulated jet plumes on an 040A space shuttle launch configuration at m=1.6 to 2.2

    Science.gov (United States)

    Dods, J. B., Jr.; Brownson, J. J.; Kassner, D. L.; Blackwell, K. L.; Decker, J. P.; Roberts, B. B.

    1974-01-01

    The effect of plume-induced flow separation and aspiration effects due to operation of both orbiter and the solid rocket motors on a 0.019-scale model of the launch configuration of the Space Shuttle Vehicle is determined. Longitudinal and lateral-directional stability data were obtained at Mach numbers of 1.6, 2.0, and 2.2 with and without the engines operating. The plumes exiting from the engines were simulated by a cold-gas jet supplied by an auxiliary 200-atm air supply system and solid-body plume simulators. The aerodynamic effects produced by these two simulation procedures are compared. The parameters most significantly affected by the jet plumes are pitching moment, elevon control effectiveness, axial force, and orbiter wing loads. The solid rocket motor (SRM) plumes have the largest effect on the aerodynamic characteristics. The effect of the orbiter plumes in combination with the SRM plumes is also significant. Variations in the nozzle design parameters and configuration changes can reduce the jet plume-induced aerodynamic effects.

  16. The Decomposition of Hydrazine in the Gas Phase and over an Iridium Catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Michael W. [Ames Laboratory; Gordon, Mark S. [Ames Laboratory

    2013-09-30

    Hydrazine is an important rocket fuel, used as both a monopropellant and a bipropellant. This paper presents theoretical results to complement the extensive experimental studies of the gas phase and Ir catalyzed decompositions involved in the monopropellant applications of hydrazine. Gas phase electronic structure theory calculations that include electron correlation predict that numerous molecular and free radical reactions occur within the same energy range as the basic free radical pathways: NN bond breaking around 65 kcal/mol and NH bond breaking around 81 kcal/mol. The data suggest that a revision to existing kinetics modeling is desirable, based on the energetics and the new elementary steps reported herein. A supported Ir-6 octahedron model for the Shell 405 Iridium catalyst used in thrusters was developed. Self-Consistent Field and electron correlation calculations (with core potentials and associated basis sets) find a rich chemistry for hydrazine on this catalyst model. The model catalyst provides dramatically lower NN and NH bond cleavage energies and an even smaller barrier to breaking the NH bond by NH2 abstractions. Thus, the low temperature decomposition over the catalyst is interpreted in terms of consecutive NH2 abstractions to produce ammonia and nitrogen. The higher temperature channel, which has hydrogen and nitrogen products, may be due to a mixture of two mechanisms. These two mechanisms are successive NH cleavages with surface H + H recombinations, and the same type of assisted H-2 eliminations found to occur in the gas phase part of this study.

  17. Alkalization of steam and condensate with 2-amino-1-butanol and hydrazine; Alkalisering av aanga och kondensat med butanolamin och hydrazin

    Energy Technology Data Exchange (ETDEWEB)

    Falk, I. [Studsvik Material AB, Nykoeping (Sweden)

    1996-04-01

    To maintain a low corrosion level in steam- and condensate systems at power and industrial plants, an alkalization of the steam is needed. A low corrosion level lowers the risk of operation disturbances and reduces the cost of the condensate clean up. A better knowledge in the behavior of the alkalis will improve the possibilities to avoid the corrosion attacks. In this work experimental measurements have been carried out during steam boiler conditions as temperature, continuous steam generation and condensation. It has been found that the volatility of 2-amino-1-butanol is very low during stationary dynamic conditions at 250 deg C and 120 deg C. To achieve a high ph-value in the final condensate a very high concentration of 2-amino-1-butanol is thus needed especially when the steam contains acidic compounds. The alkalization effect is obtained from ammonia which is created by thermal decomposition of hydrazine in the boiler water. It is necessary to carry out experimental investigations showing the thermal stability of organic compounds in boiler water before it is possible to recommend them as better volatile alkalis than ammonia and hydrazine. 6 refs, 13 figs

  18. A global sensitivity analysis of the PlumeRise model of volcanic plumes

    Science.gov (United States)

    Woodhouse, Mark J.; Hogg, Andrew J.; Phillips, Jeremy C.

    2016-10-01

    Integral models of volcanic plumes allow predictions of plume dynamics to be made and the rapid estimation of volcanic source conditions from observations of the plume height by model inversion. Here we introduce PlumeRise, an integral model of volcanic plumes that incorporates a description of the state of the atmosphere, includes the effects of wind and the phase change of water, and has been developed as a freely available web-based tool. The model can be used to estimate the height of a volcanic plume when the source conditions are specified, or to infer the strength of the source from an observed plume height through a model inversion. The predictions of the volcanic plume dynamics produced by the model are analysed in four case studies in which the atmospheric conditions and the strength of the source are varied. A global sensitivity analysis of the model to a selection of model inputs is performed and the results are analysed using parallel coordinate plots for visualisation and variance-based sensitivity indices to quantify the sensitivity of model outputs. We find that if the atmospheric conditions do not vary widely then there is a small set of model inputs that strongly influence the model predictions. When estimating the height of the plume, the source mass flux has a controlling influence on the model prediction, while variations in the plume height strongly effect the inferred value of the source mass flux when performing inversion studies. The values taken for the entrainment coefficients have a particularly important effect on the quantitative predictions. The dependencies of the model outputs to variations in the inputs are discussed and compared to simple algebraic expressions that relate source conditions to the height of the plume.

  19. Sulfur chemistry in a copper smelter plume

    Science.gov (United States)

    Eatough, D. J.; Christensen, J. J.; Eatough, N. I.; Hill, M. W.; Major, T. D.; Mangelson, N. F.; Post, M. E.; Ryder, J. F.; Hansen, L. D.; Meisenheimer, R. G.; Fischer, J. W.

    Sulfur transformation chemistry was studied in the plume of the Utah smelter of Kennecott Copper Corporation from April to October 1977. Samples were taken at up to four locations from 4 to 60 km from the stacks. Data collected at each station included: SO 2 concentration, low-volume collected total paniculate matter, high-volume collected size fractionated paniculate matter, wind velocity and direction, temperature, and relative humidity. Paniculate samples were analyzed for S(IV). sulfate, strong acid, anions, cations, and elemental concentrations using calorimetric, ion Chromatographie, FIXE, ESCA, ion microprobe, and SEM-ion microprobe techniques. The concentration of As in the paniculate matter was used as a conservative plume tracer. The ratios Mo/As, Pb/As, and Zn/As were constant in particulate matter collected at all sampling sites for any particle size. Strong mineral acid was neutralized by background metal oxide and/or carbonate particulates within 40km of the smelter. This neutralization process is limited only by the rate of incorporation of basic material into the plume. Two distinct metal-S(IV) species similar to those observed in laboratory aerosol experiments were found in the plume. The formation of paniculate S(IV) species occurs by interaction of SO 2 (g) with both ambient and plume derived aerosol and is equilibrium controlled. The extent of formation of S(IV) complexes in the aerosol is directly proportional to the SO 2(g) and paniculate (Cu + Fe) concentration and inversely proportional to the paniculate acidity. S(IV) species were stable in collected paniculate matter only in the neutralized material, but with proper sampling techniques could be demonstrated to also be present in very acidic particles at high ambient SO 2(g) concentrations. Reduction of arsenate to arsenite by the aerosol S(IV) complexes during plume transport is suggested. The SO 2(g)-sulfate conversion process in the plume is described by a mechanism which is first order

  20. Particle Size Distributions Measured in the Stratospheric Plumes of Three Rockets During the ACCENT Missions

    Science.gov (United States)

    Wiedinmyer, C.; Brock, C. A.; Reeves, J. M.; Ross, M. N.; Schmid, O.; Toohey, D.; Wilson, J. C.

    2001-12-01

    The global impact of particles emitted by rocket engines on stratospheric ozone is not well understood, mainly due to the lack of comprehensive in situ measurements of the size distributions of these emitted particles. During the Atmospheric Chemistry of Combustion Emissions Near the Tropopause (ACCENT) missions in 1999, the NASA WB-57F aircraft carried the University of Denver N-MASS and FCAS instruments into the stratospheric plumes from three rockets. Size distributions of particles with diameters from 4 to approximately 2000 nm were calculated from the instrument measurements using numerical inversion techniques. The data have been averaged over 30-second intervals. The particle size distributions observed in all of the rocket plumes included a dominant mode near 60 nm diameter, probably composed of alumina particles. A smaller mode at approximately 25 nm, possibly composed of soot particles, was seen in only the plumes of rockets that used liquid oxygen and kerosene as a propellant. Aircraft exhaust emitted by the WB-57F was also sampled; the size distributions within these plumes are consistent with prior measurements in aircraft plumes. The size distributions for all rocket intercepts have been fitted to bimodal, lognormal distributions to provide input for global models of the stratosphere. Our data suggest that previous estimates of the solid rocket motor alumina size distributions may underestimate the alumina surface area emission index, and so underestimate the particle surface area available for heterogeneous chlorine activation reactions in the global stratosphere.

  1. Microbial populations in contaminant plumes

    Science.gov (United States)

    Haack, Sheridan K.; Bekins, Barbara A.

    Efficient biodegradation of subsurface contaminants requires two elements: (1) microbial populations with the necessary degradative capabilities, and (2) favorable subsurface geochemical and hydrological conditions. Practical constraints on experimental design and interpretation in both the hydrogeological and microbiological sciences have resulted in limited knowledge of the interaction between hydrogeological and microbiological features of subsurface environments. These practical constraints include: (1) inconsistencies between the scales of investigation in the hydrogeological and microbiological sciences, and (2) practical limitations on the ability to accurately define microbial populations in environmental samples. However, advances in application of small-scale sampling methods and interdisciplinary approaches to site investigations are beginning to significantly improve understanding of hydrogeological and microbiological interactions. Likewise, culture-based and molecular analyses of microbial populations in subsurface contaminant plumes have revealed significant adaptation of microbial populations to plume environmental conditions. Results of recent studies suggest that variability in subsurface geochemical and hydrological conditions significantly influences subsurface microbial-community structure. Combined investigations of site conditions and microbial-community structure provide the knowledge needed to understand interactions between subsurface microbial populations, plume geochemistry, and contaminant biodegradation. La biodégradation efficace des polluants souterrains requiert deux éléments: des populations microbiennes possédant les aptitudes nécessaires à la dégradation, et des conditions géochimiques et hydrologiques souterraines favorables. Des contraintes pratiques sur la conception et l'interprétation des expériences à la fois en microbiologie et en hydrogéologie ont conduit à une connaissance limitée des interactions entre les

  2. PlumeSat: A Micro-Satellite Based Plume Imagery Collection Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Ledebuhr, A.G.; Ng, L.C.

    2002-06-30

    This paper describes a technical approach to cost-effectively collect plume imagery of boosting targets using a novel micro-satellite based platform operating in low earth orbit (LEO). The plume collection Micro-satellite or PlueSat for short, will be capable of carrying an array of multi-spectral (UV through LWIR) passive and active (Imaging LADAR) sensors and maneuvering with a lateral divert propulsion system to different observation altitudes (100 to 300 km) and different closing geometries to achieve a range of aspect angles (15 to 60 degrees) in order to simulate a variety of boost phase intercept missions. The PlumeSat will be a cost effective platform to collect boost phase plume imagery from within 1 to 10 km ranges, resulting in 0.1 to 1 meter resolution imagery of a variety of potential target missiles with a goal of demonstrating reliable plume-to-hardbody handover algorithms for future boost phase intercept missions. Once deployed on orbit, the PlumeSat would perform a series phenomenology collection experiments until expends its on-board propellants. The baseline PlumeSat concept is sized to provide from 5 to 7 separate fly by data collects of boosting targets. The total number of data collects will depend on the orbital basing altitude and the accuracy in delivering the boosting target vehicle to the nominal PlumeSat fly-by volume.

  3. Coronal Plumes in the Fast Solar Wind

    Science.gov (United States)

    Velli, Marco; Lionello, Roberto; Linker, Jon A.; Mikic, Zoran

    2011-01-01

    The expansion of a coronal hole filled with a discrete number of higher density coronal plumes is simulated using a time-dependent two-dimensional code. A solar wind model including an exponential coronal heating function and a flux of Alfven waves propagating both inside and outside the structures is taken as a basic state. Different plasma plume profiles are obtained by using different scale heights for the heating rates. Remote sensing and solar wind in situ observations are used to constrain the parameter range of the study. Time dependence due to plume ignition and disappearance is also discussed. Velocity differences of the order of approximately 50 km/s, such as those found in microstreams in the high-speed solar wind, may be easily explained by slightly different heat deposition profiles in different plumes. Statistical pressure balance in the fast wind data may be masked by the large variety of body and surface waves which the higher density filaments may carry, so the absence of pressure balance in the microstreams should not rule out their interpretation as the extension of coronal plumes into interplanetary space. Mixing of plume-interplume material via the Kelvin-Helmholtz instability seems to be possible within the parameter ranges of the models defined here, only at large di stances from the Sun, beyond 0.2-0.3 AU. Plasma and composition measurements in the inner heliosphere, such as those which will become available with Solar Orbiter and Solar Probe Plus, should therefore definitely be able to identify plume remnants in the solar wind.

  4. Intramolecular Electron Transfer in Bis(tetraalkyl Hydrazine) and Bis(hydrazyl) Radical Cations.

    Science.gov (United States)

    Chang, Hao

    A series of multicyclic bis(hydrazine) and bis(diazenium) compounds connected by relatively rigid hydrocarbon frameworks were prepared for the study of intramolecular electron transfer. The thermodynamics of electron removal of these compounds was investigated by cyclic voltammetry. The difference between the first and second oxidation potentials for the 4 sigma-bonded species was found to be larger for the bis(hydrazyl) radical systems than for the bis(hydrazines) by ca. 0.2 V (4.6 kcal/mol). This indicates a greater degree of interaction between the two nitrogen moieties for the hydrazyl systems, which is consistent with a greater degree of electronic coupling (H _{rm AB}) in these systems. The ESR spectra of the 4 sigma -bonded bis(hydrazine) radical cations indicate localized radical cations, which corresponds to slow intramolecular electron transfer on the ESR timescale. Conversely, the ESR spectra of the corresponding bis(hydrazyl) radical cation systems show nitrogen hyperfine splittings of a(4N) of ca. 4.5 G. This indicates that intramolecular electron transfer between the two nitrogen moieties is fast on the ESR timescale; the rate of exchange, k_ {rm ex} was estimated to be well above 1.9 times 10^8 s^{-1}. The contrast in exchange rates is consistent with the large geometry change upon oxidation which is characteristic of hydrazines. The hydrazyls undergo a smaller geometry change upon oxidation, and thus are expected to exhibit smaller inner-sphere reorganization energies. The optical spectra of these radical species was investigated in hopes of observing absorption bands corresponding to intramolecular electron transfer, as predicted by Hush theory. A broad absorption band was observed in the near IR region for the saturated bis(hydrazyl) radical cation system at 1060 nm (9420 cm^{-1} ) in acetonitrile at room temperature, and was accompanied by a narrower band at 1430 nm (6993 cm^ {-1}). The width of this band was estimated to be 545 nm (6496 cm^{-1

  5. Wind-Forced Baroclinic Beta-Plumes

    Science.gov (United States)

    Belmadani, A.; Maximenko, N. A.; Melnichenko, O.; Schneider, N.; Di Lorenzo, E.

    2011-12-01

    A planetary beta-plume is a classical example of oceanic circulation induced by a localized vorticity source or sink that allows an analytical description in simplistic cases. Its barotropic structure is a zonally-elongated, gyre-like cell governed by the Sverdrup circulation on the beta-plane. The dominant zonal currents, found west of the source/sink, are often referred to as zonal jets. This simple picture describes the depth-integrated flow. Previous studies have investigated beta-plumes in a reduced-gravity framework or using other simple models with a small number of vertical layers, thereby lacking representation of the vertical structure. In addition, most previous studies use a purely linear regime without considering the role of eddies. However, these jets are often associated with strong lateral shear that makes them unstable under increased forcing. The circulation in such a nonlinear regime may involve eddy-mean flow interactions, which modify the time-averaged circulation. Here, the baroclinic structures of linear and nonlinear wind-forced beta-plumes are studied using a continuously-stratified, primitive equation, eddy-permitting ocean model (ROMS). The model is configured in an idealized rectangular domain for the subtropical ocean with a flat bottom. The surface wind forcing is a steady anticyclonic Gaussian wind vortex, which provides a localized vorticity source in the center of the domain. The associated wind stress curl and Ekman pumping comprise downwelling in the vortex center surrounded by a ring of weaker upwelling. Under weak forcing, the simulated steady-state circulation corresponds well with a theoretical linear beta-plume. While its depth-integrated transport exhibits a set of zonal jets, consistent with Sverdrup theory, the baroclinic structure of the plume is remarkably complex. Relatively fast westward decay of the surface currents occurs simultaneously with the deepening of the lower boundary of the plume. This deepening suggests

  6. Confirmation of Water Plumes on Europa

    Science.gov (United States)

    Sparks, William

    Evidence was found for plumes of water ice venting from the polar regions of Europa (Roth et al 2014a) - FUV detection of off-limb line emission from the dissociation products of water. We find additional evidence for the presence of ice plumes on Europa from HST transit imaging observations (Sparks et al 2016). The evidence for plumes remains marginal, 4-sigma, and there is considerable debate as to their reality. SOFIA can potentially resolve this issue with an unambiguous direct detection of water vapor using EXES. Detection of the fundamental vibrational mode of water vapor at 6 micron, as opposed to the atomic constituents of water, would prove that the plumes exist and inform us of their physical chemistry through quantitative consideration of the balance between water vapor and its dissociation products, hydrogen and oxygen. We propose to obtain spectra of the leading and trailing hemispheres separately, with trailing as the higher priority. These provide two very different physical environments and plausibly different degrees of activity. If the plumes of Europa arise from the deep ocean, we have gained access to probably the most astrobiologically interesting location in the Solar System, and clarify an issue of major strategic importance in NASAs planning for its multi-billion dollar mission to Europa.

  7. Modelling of aerosol processes in plumes

    Energy Technology Data Exchange (ETDEWEB)

    Lazaridis, M.; Isukapalli, S.S.; Georgopoulos, P.G. [Norwegian Institute of Air Research, Kjeller (Norway)

    2001-07-01

    A modelling platform for studying photochemical gaseous and aerosol phase processes from localized (e.g., point) sources has been presented. The current approach employs a reactive plume model which extends the regulatory model RPM-IV by incorporating aerosol processes and heterogeneous chemistry. The physics and chemistry of elemental carbon, organic carbon, sulfate, nitrate, ammonium material of aerosols are treated and attributed to the PM size distribution. A modified version of the carbon bond IV chemical mechanism is included to model the formation of organic aerosol. Aerosol dynamics modeled include mechanisms of nucleation, condensation, dry deposition and gas/particle partitioning of organic matter. The model is first applied to a number of case studies involving emissions from point sources and sulfate particle formation in plumes. Model calculations show that homogeneous nucleation is an efficient process for new particle formation in plumes, in agreement with previous field studies and theoretical predictions. In addition, the model is compared with field data from power plant plumes with satisfactory predictions against gaseous species and total sulphate mass measurements. Finally, the plume model is applied to study secondary organic matter formation due to various emission categories such as vehicles and the oil production sector.

  8. Intermittent heat instabilities in an air plume

    Science.gov (United States)

    Le Mouël, Jean-Louis; Kossobokov, Vladimir G.; Perrier, Frederic; Morat, Pierre

    2016-08-01

    We report the results of heating experiments carried out in an abandoned limestone quarry close to Paris, in an isolated room of a volume of about 400 m3. A heat source made of a metallic resistor of power 100 W was installed on the floor of the room, at distance from the walls. High-quality temperature sensors, with a response time of 20 s, were fixed on a 2 m long bar. In a series of 24 h heating experiments the bar had been set up horizontally at different heights or vertically along the axis of the plume to record changes in temperature distribution with a sampling time varying from 20 to 120 s. When taken in averages over 24 h, the temperatures present the classical shape of steady-state plumes, as described by classical models. On the contrary, the temperature time series show a rich dynamic plume flow with intermittent trains of oscillations, spatially coherent, of large amplitude and a period around 400 s, separated by intervals of relative quiescence whose duration can reach several hours. To our knowledge, no specific theory is available to explain this behavior, which appears to be a chaotic interaction between a turbulent plume and a stratified environment. The observed behavior, with first-order factorization of a smooth spatial function with a global temporal intermittent function, could be a universal feature of some turbulent plumes in geophysical environments.

  9. Near field characteristics of buoyant helium plumes

    Indian Academy of Sciences (India)

    Kuchimanchi K Bharadwaj; Debopam Das; Pavan K Sharma

    2015-05-01

    Puffing and entrainment characteristics of helium plumes emanating out into ambient air from a circular orifice are investigated in the present study. Velocity and density fields are measured across a diametric plane using Particle Image Velocimetry (PIV) and Planar Laser Induced Fluorescence (PLIF) respectively in phase resolved manner. Experiments are performed in Froude numbers range 0.2–0.4 and for Reynolds numbers 58–248. Puffing frequency measurements reveal that the plume puffing frequencies are insensitive to the plume exit conditions, since the instability is buoyancy driven. The frequencies obtained in the present case are in agreement with frequencies obtained by Cetegen & Kasper (1996) for plumes originating from circular nozzles of various L/D ratios. Velocity and density measurements reveal that toroidal vortex formed during a puffing cycle entrains ambient air as it traverses downstream and this periodic engulfment governs the entrainment mechanism in pulsating plumes. The obtained velocity and density fields are used to calculate mass entrainment rates. It is revealed that though the flow is unsteady, the contribution of unsteady term in mass conservation to entrainment is negligible, and it becomes zero over a puff cycle. Finally, an empirical relation for variation of mass entrainment with height has been proposed, in which the non-dimensional mass entrainment is found to follow a power law with the non-dimensional height.

  10. Mantle plumes in the vicinity of subduction zones

    Science.gov (United States)

    Mériaux, C. A.; Mériaux, A.-S.; Schellart, W. P.; Duarte, J. C.; Duarte, S. S.; Chen, Z.

    2016-11-01

    We present three-dimensional deep-mantle laboratory models of a compositional plume within the vicinity of a buoyancy-driven subducting plate with a fixed trailing edge. We modelled front plumes (in the mantle wedge), rear plumes (beneath the subducting plate) and side plumes with slab/plume systems of buoyancy flux ratio spanning a range from 2 to 100 that overlaps the ratios in nature of 0.2-100. This study shows that 1) rising side and front plumes can be dragged over thousands of kilometres into the mantle wedge, 2) flattening of rear plumes in the trench-normal direction can be initiated 700 km away from the trench, and a plume material layer of lesser density and viscosity can ultimately almost entirely underlay a retreating slab after slab/plume impact, 3) while side and rear plumes are not tilted until they reach ∼600 km depth, front plumes can be tilted at increasing depths as their plume buoyancy is lessened, and rise at a slower rate when subjected to a slab-induced downwelling, 4) rear plumes whose buoyancy flux is close to that of a slab, can retard subduction until the slab is 600 km long, and 5) slab-plume interaction can lead to a diversity of spatial plume material distributions into the mantle wedge. We discuss natural slab/plume systems of the Cascadia/Bowie-Cobb, and Nazca/San Felix-Juan Fernandez systems on the basis of our experiments and each geodynamic context and assess the influence of slab downwelling at depths for the starting plumes of Java, Coral Sea and East Solomon. Overall, this study shows how slab/plume interactions can result in a variety of geological, geophysical and geochemical signatures.

  11. Health monitoring of rocket engines using image processing

    Science.gov (United States)

    Disimile, Peter J.; Shoe, Bridget; Toy, Norman

    1991-07-01

    Analysis of spectral and video data for anomalous events occurring in the exhaust plume of the Space Shuttle Main Engine (SSME) has shown that the improved time resolution of video tape increases the detection rate of anomalies in the visual region. Preliminary developments and applications of image processing techniques are used to extract information from video data of the SSME exhaust plume. Images have been enhanced to show the exhaust plume shock structure and for the isolation of an anomalous event.

  12. The 2016 Case for Mantle Plumes and a Plume-Fed Asthenosphere (Augustus Love Medal Lecture)

    Science.gov (United States)

    Morgan, Jason P.

    2016-04-01

    The process of science always returns to weighing evidence and arguments for and against a given hypothesis. As hypotheses can only be falsified, never universally proved, doubt and skepticism remain essential elements of the scientific method. In the past decade, even the hypothesis that mantle plumes exist as upwelling currents in the convecting mantle has been subject to intense scrutiny; from geochemists and geochronologists concerned that idealized plume models could not fit many details of their observations, and from seismologists concerned that mantle plumes can sometimes not be 'seen' in their increasingly high-resolution tomographic images of the mantle. In the place of mantle plumes, various locally specific and largely non-predictive hypotheses have been proposed to explain the origins of non-plate boundary volcanism at Hawaii, Samoa, etc. In my opinion, this debate has now passed from what was initially an extremely useful restorative from simply 'believing' in the idealized conventional mantle plume/hotspot scenario to becoming an active impediment to our community's ability to better understand the dynamics of the solid Earth. Having no working hypothesis at all is usually worse for making progress than having an imperfect and incomplete but partially correct one. There continues to be strong arguments and strong emerging evidence for deep mantle plumes. Furthermore, deep thermal plumes should exist in a mantle that is heated at its base, and the existence of Earth's (convective) geodynamo clearly indicates that heat flows from the core to heat the mantle's base. Here I review recent seismic evidence by French, Romanowicz, and coworkers that I feel lends strong new observational support for the existence of deep mantle plumes. I also review recent evidence consistent with the idea that secular core cooling replenishes half the mantle's heat loss through its top surface, e.g. that the present-day mantle is strongly bottom heated. Causes for

  13. Simple model of a cooling tower plume

    Science.gov (United States)

    Jan, Cizek; Jiri, Nozicka

    2016-06-01

    This article discusses the possibilities in the area of modeling of the so called cooling tower plume emergent at operating evaporating cooling systems. As opposed to recent publication, this text focuses on the possibilities of a simplified analytic description of the whole problem where this description shall - in the future - form the base of a calculation algorithms enabling to simulate the efficiency of systems reducing this cooling tower plume. The procedure is based on the application of basic formula for the calculation of the velocity and concentration fields in the area above the cooling tower. These calculation is then used to determine the form and the total volume of the plume. Although this approach does not offer more exact results, it can provide a basic understanding of the impact of individual quantities relating to this problem.

  14. A collisionless plasma thruster plume expansion model

    Science.gov (United States)

    Merino, Mario; Cichocki, Filippo; Ahedo, Eduardo

    2015-06-01

    A two-fluid model of the unmagnetized, collisionless far region expansion of the plasma plume for gridded ion thrusters and Hall effect thrusters is presented. The model is integrated into two semi-analytical solutions valid in the hypersonic case. These solutions are discussed and compared against the results from the (exact) method of characteristics; the relative errors in density and velocity increase slowly axially and radially and are of the order of 10-2-10-3 in the cases studied. The plasma density, ion flux and ambipolar electric field are investigated. A sensitivity analysis of the problem parameters and initial conditions is carried out in order to characterize the far plume divergence angle in the range of interest for space electric propulsion. A qualitative discussion of the physics of the secondary plasma plume is also provided.

  15. Numerical and approximate solutions for plume rise

    Science.gov (United States)

    Krishnamurthy, Ramesh; Gordon Hall, J.

    Numerical and approximate analytical solutions are compared for turbulent plume rise in a crosswind. The numerical solutions were calculated using the plume rise model of Hoult, Fay and Forney (1969, J. Air Pollut. Control Ass.19, 585-590), over a wide range of pertinent parameters. Some wind shear and elevated inversion effects are included. The numerical solutions are seen to agree with the approximate solutions over a fairly wide range of the parameters. For the conditions considered in the study, wind shear effects are seen to be quite small. A limited study was made of the penetration of elevated inversions by plumes. The results indicate the adequacy of a simple criterion proposed by Briggs (1969, AEC Critical Review Series, USAEC Division of Technical Information extension, Oak Ridge, Tennesse).

  16. Properties of industrial dense gas plumes

    Science.gov (United States)

    Shaver, E. M.; Forney, L. J.

    Hazardous gases and vapors are often discharged into the atmosphere from industrial plants during catastrophic events (e.g. Union Carbide incident in Bhopal, India). In many cases the discharged components are more dense than air and settle to the ground surface downstream from the stack exit. In the present paper, the buoyant plume model of Hoult, Fay and Forney (1969, J. Air Pollut. Control Ass. 19, 585-590.) has been altered to predict the properties of hazardous discharges. In particular, the plume impingement point, radius and concentration are predicted for typical stack exit conditions, wind speeds and temperature profiles. Asymptotic expressions for plume properties at the impingement point are also derived for a constant crosswind and neutral temperature profile. These formulae are shown to be useful for all conditions.

  17. Modeling the Enceladus plume--plasma interaction

    CERN Document Server

    Fleshman, B L; Bagenal, F

    2010-01-01

    We investigate the chemical interaction between Saturn's corotating plasma and Enceladus' volcanic plumes. We evolve plasma as it passes through a prescribed H2O plume using a physical chemistry model adapted for water-group reactions. The flow field is assumed to be that of a plasma around an electrically-conducting obstacle centered on Enceladus and aligned with Saturn's magnetic field, consistent with Cassini magnetometer data. We explore the effects on the physical chemistry due to: (1) a small population of hot electrons; (2) a plasma flow decelerated in response to the pickup of fresh ions; (3) the source rate of neutral H2O. The model confirms that charge exchange dominates the local chemistry and that H3O+ dominates the water-group composition downstream of the Enceladus plumes. We also find that the amount of fresh pickup ions depends heavily on both the neutral source strength and on the presence of a persistent population of hot electrons.

  18. Carcinogenicity and chronic toxicity of hydrazine monohydrate in rats and mice by two-year drinking water treatment.

    Science.gov (United States)

    Matsumoto, Michiharu; Kano, Hirokazu; Suzuki, Masaaki; Katagiri, Taku; Umeda, Yumi; Fukushima, Shoji

    2016-04-01

    The carcinogenicity and chronic toxicity of hydrazine monohydrate was examined by administrating hydrazine monohydrate in drinking water to groups of 50 F344/DuCrj rats and 50 Crj:BDF1 mice of both sexes for two years. The drinking water concentration of hydrazine monohydrate was 0, 20, 40 or 80 ppm (wt/wt) for male and female rats and male mice; and 0, 40, 80 or 160 ppm for female mice. Survival rates of each group of males and females rats and mice were similar to the respective controls, except female rats administered 80 ppm. Two-year administration of hydrazine monohydrate produced an increase in the incidences of hepatocellular adenomas and carcinomas in rats of both sexes along with hepatic foci. In mice, the incidences of hepatocellular adenomas and carcinomas were increased in females, and significantly increased incidences of hepatocellular adenomas in females administered 160 ppm were observed. Thus, hydrazine monohydrate is carcinogenic in two species, rats and mice. Additionally, non-neoplastic renal lesions in rats and mice and non-neoplastic nasal lesions in mice were observed.

  19. An Improved Calibration Method for Hydrazine Monitors for the United States Air Force

    Energy Technology Data Exchange (ETDEWEB)

    Korsah, K

    2003-07-07

    This report documents the results of Phase 1 of the ''Air Force Hydrazine Detector Characterization and Calibration Project''. A method for calibrating model MDA 7100 hydrazine detectors in the United States Air Force (AF) inventory has been developed. The calibration system consists of a Kintek 491 reference gas generation system, a humidifier/mixer system which combines the dry reference hydrazine gas with humidified diluent or carrier gas to generate the required humidified reference for calibrations, and a gas sampling interface. The Kintek reference gas generation system itself is periodically calibrated using an ORNL-constructed coulometric titration system to verify the hydrazine concentration of the sample atmosphere in the interface module. The Kintek reference gas is then used to calibrate the hydrazine monitors. Thus, coulometric titration is only used to periodically assess the performance of the Kintek reference gas generation system, and is not required for hydrazine monitor calibrations. One advantage of using coulometric titration for verifying the concentration of the reference gas is that it is a primary standard (if used for simple solutions), thereby guaranteeing, in principle, that measurements will be traceable to SI units (i.e., to the mole). The effect of humidity of the reference gas was characterized by using the results of concentrations determined by coulometric titration to develop a humidity correction graph for the Kintek 491 reference gas generation system. Using this calibration method, calibration uncertainty has been reduced by 50% compared to the current method used to calibrate hydrazine monitors in the Air Force inventory and calibration time has also been reduced by more than 20%. Significant findings from studies documented in this report are the following: (1) The Kintek 491 reference gas generation system (generator, humidifier and interface module) can be used to calibrate hydrazine detectors. (2) The

  20. Effects of meteorological conditions on spore plumes

    Science.gov (United States)

    Burch, M.; Levetin, E.

    2002-05-01

    Fungal spores are an ever-present component of the atmosphere, and have long been known to trigger asthma and hay fever symptoms in sensitive individuals. The atmosphere around Tulsa has been monitored for airborne spores and pollen with Burkard spore traps at several sampling stations. This study involved the examination of the hourly spore concentrations on days that had average daily concentrations near 50,000 spores/m3 or greater. Hourly concentrations of Cladosporium, Alternaria, Epicoccum, Curvularia, Pithomyces, Drechslera, smut spores, ascospores, basidiospores, other, and total spores were determined on 4 days at three sites and then correlated with hourly meteorological data including temperature, rainfall, wind speed, dew point, air pressure, and wind direction. On each of these days there was a spore plume, a phenomenon in which spore concentrations increased dramatically over a very short period of time. Spore plumes generally occurred near midday, and concentrations were seen to increase from lows around 20,000 total spores/m3 to highs over 170,000 total spores/m3 in 2 h. Multiple regression analysis of the data indicated that increases in temperature, dew point, and air pressure correlated with the increase in spore concentrations, but no single weather variable predicted the appearance of a spore plume. The proper combination of changes in these meteorological parameters that result in a spore plume may be due to the changing weather conditions associated with thunderstorms, as on 3 of the 4 days when spore plumes occurred there were thunderstorms later that evening. The occurrence of spore plumes may have clinical significance, because other studies have shown that sensitization to certain spore types can occur during exposure to high spore concentrations.

  1. Cassini Radio Occultation by Enceladus Plume

    Science.gov (United States)

    Kliore, A.; Armstrong, J.; Flasar, F.; French, R.; Marouf, E.; Nagy, A.; Rappaport, N.; McGhee, C.; Schinder, P.; Anabtawi, A.; Asmar, S.; Barbinis, E.; Fleischman, D.; Goltz, G.; Aguilar, R.; Rochblatt, D.

    2006-12-01

    A fortuitous Cassini radio occultation by Enceladus plume occurs on September 15, 2006. The occultation track (the spacecraft trajectory in the plane of the sky as viewed from the Earth) has been designed to pass behind the plume (to pass above the south polar region of Enceladus) in a roughly symmetrical geometry centered on a minimum altitude above the surface of about 20 km. The minimum altitude was selected primarily to ensure probing much of the plume with good confidence given the uncertainty in the spacecraft trajectory. Three nearly-pure sinusoidal signals of 0.94, 3.6, and 13 cm-wavelength (Ka-, X-, and S-band, respectively) are simultaneously transmitted from Cassini and are monitored at two 34-m Earth receiving stations of the Deep Space Network (DSN) in Madrid, Spain (DSS-55 and DSS-65). The occultation of the visible plume is extremely fast, lasting less than about two minutes. The actual observation time extends over a much longer time interval, however, to provide a good reference baseline for potential detection of signal perturbations introduced by the tenuous neutral and ionized plume environment. Given the likely very small fraction of optical depth due to neutral particles of sizes larger than about 1 mm, detectable changes in signal intensity is perhaps unlikely. Detection of plume plasma along the radio path as perturbations in the signals frequency/phase is more likely and the magnitude will depend on the electron columnar density probed. The occultation time occurs not far from solar conjunction time (Sun-Earth-probe angle of about 33 degrees), causing phase scintillations due to the solar wind to be the primary limiting noise source. We estimate a delectability limit of about 1 to 3E16 electrons per square meter columnar density assuming about 100 seconds integration time. Potential measurement of the profile of electron columnar density along the occultation track is an exciting prospect at this time.

  2. Plume head - trench interaction: impact on subduction dynamics

    Science.gov (United States)

    Betts, P. G.; Moresi, L. N.; Mason, W. G.; Willis, D.

    2013-12-01

    The geologic record provides numerous examples where plumes and their associated buoyancy swell have disrupted convergent plate margins. These interactions have produced a variety of responses in the overriding plate including transient episodes of arc amagmatism, transient episodes of crustal shortening followed by plume-related magmatism in the overriding plate. The latter observation implies the plume must have transitioned from the subducting plate to the overriding plate. We present several 3D Underworld numerical models of plume heads of variable dimension and buoyancy interacting with a subduction trench. The models indicate that plume heads impact enormously on trench geometry. Arcuate trenches are created as the trench retreats around the edges of the plume head, whereas trench advance occurs in front of the plume resulting in transient crustal shortening in the overriding plate. Stalling of subduction when the plume head impacts the trench causes slab windowing. The size of the slab window is dependent on the size and buoyancy of the plume. The creation of the slab window provides a potential conduit for plume migration to the overriding plate. Alternatively, the plume head may be transferred to the overriding plate as subduction is re-established behind the plume. Models with "strong" slabs, characterized by high yield strengths, display different behavior. Plume-heads are entrained in the slab and are subducted without the development of a slab window.

  3. EUV Sunspot Plumes Observed with SOHO

    CERN Document Server

    Maltby, P; Brekke, P; Haugan, S V H; Kjeldseth-Moe, O; Wikstøl, O; Rimmele, T R; Wikstøl, O

    1998-01-01

    Bright EUV sunspot plumes have been observed in five out of nine sunspot regions with the Coronal Diagnostic Spectrometer -- CDS on SOHO. In the other four regions the brightest line emissions may appear inside the sunspot but are mainly concentrated in small regions outside the sunspot areas. These results are in contrast to those obtained during the Solar Maximum Mission, but are compatible with the Skylab mission results. The present observations show that sunspot plumes are formed in the upper part of the transition region, occur both in magnetic unipolar-- and bipolar regions, and may extend from the umbra into the penumbra.

  4. Halogen Chemistry in Volcanic Plumes (Invited)

    Science.gov (United States)

    Roberts, Tjarda

    2017-04-01

    Volcanoes release vast amounts of gases and particles in the atmosphere. Volcanic halogens (HF, HCl, HBr, HI) are co-emitted alongside SO2, and observations show rapid formation of BrO and OClO in the plume as it disperses into the troposphere. The development of 1D and Box models (e.g. PlumeChem) that simulate volcanic plume halogen chemistry aims to characterise how volcanic reactive halogens form and quantify their atmospheric impacts. Following recent advances, these models can broadly reproduce the observed downwind BrO/SO2 ratios using "bromine-explosion" chemistry schemes, provided they use a "high-temperature initialisation" to inject radicals (OH, Cl, Br and possibly NOx) which "kick-start" the low-temperature chemistry cycles that convert HBr into reactive bromine (initially as Br2). The modelled rise in BrO/SO2 and subsequent plateau/decline as the plume disperses downwind reflects cycling between reactive bromine, particularly Br-BrO, and BrO-HOBr-BrONO2. BrCl is produced when aerosol becomes HBr-depleted. Recent model simulations suggest this mechanism for reactive chlorine formation can broadly account for OClO/SO2 reported at Mt Etna. Predicted impacts of volcanic reactive halogen chemistry include the formation of HNO3 from NOx and depletion of ozone. This concurs with HNO3 widely reported in volcanic plumes (although the source of NOx remains under question), as well as observations of ozone depletion reported in plumes from several volcanoes (Mt Redoubt, Mt Etna, Eyjafjallajokull). The plume chemistry can transform mercury into more easily deposited and potentially toxic forms, for which observations are limited. Recent incorporation of volcanic halogen chemistry in a 3D regional model of degassing from Ambrym (Vanuatu) also predicts how halogen chemistry causes depletion of OH to lengthen the SO2 lifetime, and highlights the potential for halogen transport from the troposphere to the stratosphere. However, the model parameter-space is vast and

  5. Spectral, thermal and X-ray studies on some new bis-hydrazine metal glyoxylates and bis-hydrazine mixed metal glyoxylates

    Energy Technology Data Exchange (ETDEWEB)

    Vikram, L. [Department of Chemistry, Government Arts College, Ooty, The Nilgiris, Udhagamandalam 643002 (India); Sivasankar, B.N. [Department of Chemistry, Government Arts College, Ooty, The Nilgiris, Udhagamandalam 643002 (India)]. E-mail: sivabickol@yahoo.com

    2007-01-01

    Bis-hydrazine complexes of metal glyoxylates and mixed metal glyoxylates of 3d-metal ions of the formula M(OOCCHO){sub 2}(N{sub 2}H{sub 4}){sub 2}, where M = Mg, Mn, Co, Ni, Cu, Zn or Cd and M{sub 1/3}Co{sub 2/3}(OOCCHO){sub 2}(N{sub 2}H{sub 4}){sub 2}, where M = Mg, Mn, Ni, Zn or Cd, respectively, have been prepared and studied. The compositions of the complexes have been determined by chemical analyses. The magnetic moments and electronic spectra suggest a high-spin octahedral geometry for the metal complexes. Infrared spectral data indicate the bidentate bridging by hydrazine molecules and monodentate coordination by glyoxylate ions in both the metal and mixed metal compounds. Thermogravimetry and differential thermal analyses in air have been used to study the thermal behaviour of the complexes. The simultaneous TG-DTA traces of all the complexes show multi-step deg.radation and the final products are found to be the respective metal oxides in the case of metal complexes and metal cobaltites in the case of mixed metal complexes. The final residues were identified by their X-ray powder diffraction patterns. X-ray powder diffraction patterns of the complexes including mixed metal complexes are almost superimposable with in each of the series indicating isomorphism. The metal cobaltites MCo{sub 2}O{sub 4}, where M = Mg, Mn, Ni, Zn or Cd were also prepared by decomposing the respective mixed metal complex in a pre-heated silica crucible at about 300 deg. C, and their identities were confirmed by chemical analyses, infrared spectra and X-ray powder diffraction.

  6. Far-Field Turbulent Vortex-Wake/Exhaust Plume Interaction for Subsonic and HSCT Airplanes

    Science.gov (United States)

    Kandil, Osama A.; Adam, Ihab; Wong, Tin-Chee

    1996-01-01

    Computational study of the far-field turbulent vortex-wake/exhaust plume interaction for subsonic and high speed civil transport (HSCT) airplanes is carried out. The Reynolds-averaged Navier-Stokes (NS) equations are solved using the implicit, upwind, Roe-flux-differencing, finite-volume scheme. The two-equation shear stress transport model of Menter is implemented with the NS solver for turbulent-flow calculation. For the far-field study, the computations of vortex-wake interaction with the exhaust plume of a single engine of a Boeing 727 wing in a holding condition and two engines of an HSCT in a cruise condition are carried out using overlapping zonal method for several miles downstream. These results are obtained using the computer code FTNS3D. The results of the subsonic flow of this code are compared with those of a parabolized NS solver known as the UNIWAKE code.

  7. A distribution-based parametrization for improved tomographic imaging of solute plumes

    Science.gov (United States)

    Pidlisecky, A.; Singha, K.; Day-Lewis, F. D.

    2011-01-01

    Difference geophysical tomography (e.g. radar, resistivity and seismic) is used increasingly for imaging fluid flow and mass transport associated with natural and engineered hydrologic phenomena, including tracer experiments, in situ remediation and aquifer storage and recovery. Tomographic data are collected over time, inverted and differenced against a background image to produce 'snapshots' revealing changes to the system; these snapshots readily provide qualitative information on the location and morphology of plumes of injected tracer, remedial amendment or stored water. In principle, geometric moments (i.e. total mass, centres of mass, spread, etc.) calculated from difference tomograms can provide further quantitative insight into the rates of advection, dispersion and mass transfer; however, recent work has shown that moments calculated from tomograms are commonly biased, as they are strongly affected by the subjective choice of regularization criteria. Conventional approaches to regularization (Tikhonov) and parametrization (image pixels) result in tomograms which are subject to artefacts such as smearing or pixel estimates taking on the sign opposite to that expected for the plume under study. Here, we demonstrate a novel parametrization for imaging plumes associated with hydrologic phenomena. Capitalizing on the mathematical analogy between moment-based descriptors of plumes and the moment-based parameters of probability distributions, we design an inverse problem that (1) is overdetermined and computationally efficient because the image is described by only a few parameters, (2) produces tomograms consistent with expected plume behaviour (e.g. changes of one sign relative to the background image), (3) yields parameter estimates that are readily interpreted for plume morphology and offer direct insight into hydrologic processes and (4) requires comparatively few data to achieve reasonable model estimates. We demonstrate the approach in a series of

  8. Application of a plume model for decision makers' situation awareness during an outdoor airborne HAZMAT release.

    Science.gov (United States)

    Meris, Ronald G; Barbera, Joseph A

    2014-01-01

    In a large-scale outdoor, airborne, hazardous materials (HAZMAT) incident, such as ruptured chlorine rail cars during a train derailment, the local Incident Commanders and HAZMAT emergency responders must obtain accurate information quickly to assess the situation and act promptly and appropriately. HAZMAT responders must have a clear understanding of key information and how to integrate it into timely and effective decisions for action planning. This study examined the use of HAZMAT plume modeling as a decision support tool during incident action planning in this type of extreme HAZMAT incident. The concept of situation awareness as presented by Endsley's dynamic situation awareness model contains three levels: perception, comprehension, and projection. It was used to examine the actions of incident managers related to adequate data acquisition, current situational understanding, and accurate situation projection. Scientists and engineers have created software to simulate and predict HAZMAT plume behavior, the projected hazard impact areas, and the associated health effects. Incorporating the use of HAZMAT plume projection modeling into an incident action plan may be a complex process. The present analysis used a mixed qualitative and quantitative methodological approach and examined the use and limitations of a "HAZMAT Plume Modeling Cycle" process that can be integrated into the incident action planning cycle. HAZMAT response experts were interviewed using a computer-based simulation. One of the research conclusions indicated the "HAZMAT Plume Modeling Cycle" is a critical function so that an individual/team can be tasked with continually updating the hazard plume model with evolving data, promoting more accurate situation awareness.

  9. Ammonia and hydrazine. Transition-metal-catalyzed hydroamination and metal-free catalyzed functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, Guy [Univ. of California, San Diego, CA (United States)

    2012-06-29

    The efficient and selective preparation of organic molecules is critical for mankind. For the future, it is of paramount importance to find catalysts able to transform abundant and cheap feedstocks into useful compounds. Acyclic and heterocyclic nitrogen-containing derivatives are common components of naturally occurring compounds, agrochemicals, cosmetics, and pharmaceuticals; they are also useful intermediates in a number of industrial processes. One of the most widely used synthetic strategies, allowing the formation of an N-C bond, is the addition of an N-H bond across a carbon-carbon multiple bond, the so-called hydroamination reaction. This chemical transformation fulfills the principle of “green chemistry” since it ideally occurs with 100% atom economy. Various catalysts have been found to promote this reaction, although many limitations remain; one of the most prominent is the lack of methods that permit the use of NH3 and NH2NH2 as the amine partners. In fact, ammonia and hydrazine have rarely succumbed to homogeneous catalytic transformations. Considering the low cost and abundance of ammonia (136 million metric tons produced in 2011) and hydrazine, catalysts able to improve the reactivity and selectivity of the NH3- and NH2NH2-hydroamination reaction, and more broadly speaking the functionalization of these chemicals, are highly desirable. In the last funded period, we discovered the first homogeneous catalysts able to promote the hydroamination of alkynes and allenes with ammonia and the parent hydrazine. The key feature of our catalytic systems is that the formation of catalytically inactive Werner complexes is reversible, in marked contrast to most of the known ammonia and hydrazine transition metal complexes. This is due to the peculiar electronic properties of our neutral ancillary ligands, especially their strong donating capabilities. However, our catalysts currently require

  10. Effect of gaseous and solid simulated jet plumes on a 040A space shuttle launch configuration at Mach numbers from 1.6 to 2.2

    Science.gov (United States)

    Lanfranco, M. J.; Sparks, V. W.; Kavanaugh, A. T.

    1973-01-01

    An experimental investigation was conducted in a 9- by 7-foot supersonic wind tunnel to determine the effect of plume-induced flow separation and aspiration effects due to operation of both the orbiter and the solid rocket motors on a 0.019-scale model of the launch configuration of the space shuttle vehicle. Longitudinal and lateral-directional stability data were obtained at Mach numbers of 1.6, 2.0, and 2.2 with and without the engines operating. The plumes exiting from the engines were simulated by a cold gas jet supplied by an auxiliary 200 atmosphere air supply system, and by solid body plume simulators. Comparisons of the aerodynamic effects produced by these two simulation procedures are presented. The data indicate that the parameters most significantly affected by the jet plumes are the pitching moment, the elevon control effectiveness, the axial force, and the orbiter wing loads.

  11. Engine Throat/Nozzle Optics for Plume Spectroscopy

    Science.gov (United States)

    1991-02-01

    which describes the percentage of chrome atoms existing in an atomic state. This value from Handbook of Flame Spectroscopy by Parsons[I] is approximate...with a modified SMA connector. The bundle extends through the SMA connector and is encased in a flexible sheathing . A metal band at the fiber bundle

  12. New method for calculation of integral characteristics of thermal plumes

    DEFF Research Database (Denmark)

    Zukowska, Daria; Popiolek, Zbigniew; Melikov, Arsen Krikor

    2008-01-01

    A method for calculation of integral characteristics of thermal plumes is proposed. The method allows for determination of the integral parameters of plumes based on speed measurements performed with omnidirectional low velocity thermoanemometers. The method includes a procedure for calculation...

  13. New method for calculation of integral characteristics of thermal plumes

    DEFF Research Database (Denmark)

    2008-01-01

    A method for calculation of integral characteristics of thermal plumes is proposed. The method allows for determination of the integral parameters of plumes based on speed measurements performed with omnidirectional low velocity thermoanemometers. The method includes a procedure for calculation...

  14. Support to Aviation Control Service (SACS: an online service for near real-time satellite monitoring of volcanic plumes

    Directory of Open Access Journals (Sweden)

    H. Brenot

    2013-10-01

    Full Text Available Volcanic eruptions emit plumes of ash and gases in the atmosphere, potentially at very high altitudes. Ash rich plumes are hazardous for airplanes as ash is very abrasive and easily melts inside their engines. With more than 50 active volcanoes per year and the ever increasing number of commercial flights, the safety of airplanes is a real concern. Satellite measurements are ideal for monitoring global volcanic activity and, in combination with atmospheric dispersion models, to track and forecast volcanic plumes. Here we present the Support to Aviation Control Service (SACS, http://sacs.aeronomie.be, which is a free online service initiated by ESA for the near real-time (NRT satellite monitoring of volcanic plumes of SO2 and ash. It combines data from two UV-visible (OMI, GOME-2 and two infrared (AIRS, IASI spectrometers. This new multi-sensor warning system of volcanic plumes, running since April 2012, is based on the detection of SO2 and is optimised to avoid false alerts while at the same time limiting the number of notifications in case of large plumes. The system shows successful results with 95% of our notifications corresponding to true volcanic activity.

  15. Electrocatalytic oxidation of hydrazine with alizarin red S as a homogenous mediator on the glassy carbon electrode

    Institute of Scientific and Technical Information of China (English)

    Mohammad; Mazloum-Ardakani; Roya; Mazidi; Mohammad; Hossein; Mashhadizadeh; Parvanah; Rahimi; Mohammad; Ali; Karimi

    2010-01-01

    Electro-catalytic oxidation and detection of hydrazine on a glassy carbon electrode,at pH 6.0,was studied by using alizarin red S as a homogeneous mediator.The overall number of electrons involved in the catalytic oxidation of hydrazine and that involved in the rate-determining step were four and one,respectively.The interfering effect of some cations,anions and organic compounds were examined.Peak current for this process varied linearly with the square root of the scan rate.The kinetic parameters,such as the electron transfer coefficient(α) and catalytic rate constant(k) ,were determined using cyclic voltammetry,linear sweep voltammetry and chronoamperometry.The electro-catalytic response was optimized with regards to the pH,scan rate,hydrazine concentration and other variables.

  16. Synthesis of the row of new functional derivatives of 7-arylalkyl-8-hydrazine theophyllines

    Directory of Open Access Journals (Sweden)

    Dmytro Korobko

    2016-03-01

    Full Text Available Hydrazine functional derivatives are widely used in medical practice as remedies applied for pharmacotherapy of depression, infection diseases, hypertension, diabetes, etc. It is worth mentioning that among obtained 7-R-8-hydrazine derivatives of 1,3-dimethylxantine promising substances have been identified. Due to the fact that literature sources display only results of occasional studies of the reactions between 7-R-8-hydrazine theophyllines and mono- or dicarbonyle substances, the use of other keto reagents for xanthine bicycle at 8th position functionalization will allow to explore synthetic potential of the last one, and with high probability may lead to obtaining original biologically active substances.Aim. To study types of reaction between 8-hydrazinyl-1,3-dimethyl-7-aryl alkyl-1H-purine-2,6(3H,7H-diones and a number of carbonyl containing reagents.Methods. A nucleophilic addition reaction followed by dehydration or ethanol splitting was used, as well as the complex of the modern analysis methods to confirm the structure and individuality of the synthesized substances.Results. Different directions of 8-hydrazinyl-1,3,-dimethyl-7(fenetyl-, 3-phenylpropyl-, 3-phenylalyl-1H-purine-2,6(3H,7H-diones chemical transformations in reactions with the appropriate carbonyl containing compounds have been studied experimentally. The structure of synthesized substances was confirmed by chromatography/mass and 1H NMR spectroscopy.Conclusion. The group of 7-arylalkyl-8-(3,5-R,R1-pyrazole-1-yltheophyllines, consisting of two functionally substituted bioactive heterocycles, has been synthesized by reaction between initial substances and selected mono- and dicarbonyl compounds

  17. The synthesis and molecular recognization of the polyamine transporter of hydrazine-modified diamine conjugates

    Institute of Scientific and Technical Information of China (English)

    Jun Jun Zhou; Hao Huang; Song Qiang Xie; Yu Xia Wang; Jin Zhao; Chao Jie Wang

    2008-01-01

    A series of four novel hydrazine-modified diamine conjugates (7a-b, 8a-b) were synthesized and evaluated for cytotoxicityagainst Melanoma B 16, α-difluoromethylornithine (DFMO)-treated B 16, spermidine (SPD)-treated B 16, Mouse leukemia L 1210and Hela cell lines. Both the DFMO-B 16 and SPD-B 16 experiments indicated that conjugates 7a-b and 8a-b could recognize thepolyamine transporter (PAT) and enter the cells in part or in whole via PAT, although they were not as efficient as the reference, 9-anthracenemethyl homospermidine (1).

  18. Hydrazine Blending and Storage Facility, Interim Response Action, Final Implementation Document for Decommissioning, Phase 1

    Science.gov (United States)

    1991-03-18

    PRIMARY OBJECTIVES OF THE IRA 2. SITE INVENTORY - TANKS, PIPING, BUILDINGS, ASBEST , DEBRIS, DRUMS 3. PLAN OF ACTION - TRANSFER OF UNTREATED WASTEWATER...Response Action (IRA) H at thte Hydrazine Blending and Storage Facility (HBSF) located at Rocky Mountain Arsenal (RMA) in Commerce City , Colorado. It was...LOCATION MAP Commerce CIty , Colorado 1A U) Cl)) zr LU .i I 0< 9< z (’ICM ..w co ai >. r 0) IC., Z C’) ________________0 W jl cor cliB destruction of

  19. Hydrogenation of liquid natural rubber via diimide reduction in hydrazine hydrate/hydrogen peroxide system

    Energy Technology Data Exchange (ETDEWEB)

    Yusof, Muhammad Jefri Mohd; Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M. [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2015-09-25

    Liquid natural rubber (LNR) with molecular weight of lower than 10{sup 5} and shorter polymeric chain than natural rubber was prepared. LNR was then hydrogenated via diimide reduction by oxidation of hydrazine hydrate with hydrogen peroxide. The unsaturated units of the rubber were converted into saturated hydrocarbon to strengthen the backbone of the polymer so it was able to resist thermal degradation. The results indicated that hydrogenation degree of the product (HLNR) could be extended to 91.2% conversion under appropriate conditions. The hydrogenated LNR (HLNR) was characterized using Fourier-Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The physical characteristics of HLNR were analyzed with Termogravimetric Analysis (TGA)

  20. Alternatives to hydrazine in steam and hot water systems. Pt. 1

    Energy Technology Data Exchange (ETDEWEB)

    Hoehenberger, L.

    1989-04-01

    Ever since hydrazine was classified among the carcinogenics, users were confronted with a number of alternatives. The most common of these, i.e. ascorbate, carbohydrazide, diethyl hydroxylamine (DEHA), hydrochinine, hyposulfite, methyl ethylketoxime (MEKO), sulfite and tannines, are compared in a table with a view to their oxygen binding efficiency and other important characteristics. So far, there is no substitute with a simple reaction mechanism and optimum corrosion protection efficiency. Established physical methods are favoured for oxygen removal. Corrosion protection by passivation and inhibition are gone into. (orig.).

  1. Structure and Quantum Chemistry Study on Hexaacetyl D-Mannose Hydrazine

    Institute of Scientific and Technical Information of China (English)

    CAO Rui; LIU Xiao-Hong; CHENG Chang-Mei; WANG Ru-Ji; ZHAO Yu-Fen; WANG Lai-Xi

    2007-01-01

    Hexaacetyl D-mannose hydrazine is one type of important intermediates in saccharide chemistry. In this paper, its single crystal was obtained and furthermore, X-ray diffraction and quantum chemistry calculation were performed. It belongs to orthorhombic system, space group P212121, with a=16.267(3), b=19.263(3), c=7.1948(12)(A), Mr=446.41, Dc=1.315 g/cm3, V=2254.5(6)(A)3 and Z=4. Meanwhile, the experimental results also provide information for designing a kind of molecular switch based on the mannose nitrogenous derivatives.

  2. Effect of kaempferol on lipid peroxidation and antioxidant status in 1,2-dimethyl hydrazine induced colorectal carcinoma in rats.

    Science.gov (United States)

    Nirmala, Parthasarathy; Ramanathan, Manickam

    2011-03-01

    Colorectal cancer, a common cause of cancer related deaths in both sexes in western population is often due to persistent oxidative stress leading to DNA damage. Antioxidants scavenge free radicals and inhibit neoplastic process. Kaempferol, a flavonol widely distributed in tea, broccoli, grape fruit, brussels sprouts and apple, is claimed to have chemopreventive action in colon cancer. The aim of our study was to evaluate the effect of kaempferol on tissue lipid peroxidation and antioxidant status in 1,2-dimethyl hydrazine induced colorectal cancer in male Wistar rats and to compare its efficacy with irinotecan. Experimental colon cancer induced by 1,2-dimethyl hydrazine in rats mimic human colon cancer and therefore is an ideal model for chemoprevention studies. The rats were divided into six groups. Group 1 served as control. Group 2 received 1,2-dimethyl hydrazine (20 mg/kg body weight) subcutaneously once a week for four weeks. Group 3 received irinotecan (100 mg/kg body weight) intravenously once a week for four weeks with 1,2-dimethyl hydrazine. Groups 4 to 6 were given a daily oral dose of 50, 100, 200 mg/kg body weight of kaempferol with 1,2-dimethyl hydrazine. The total study period was 16 weeks. Kaempferol supplementation lowered 1,2-dimethyl hydrazine induced erythrocyte lysate and liver thiobarbituric acid reactive substances level and rejuvenated anti oxidant enzymes catalase, super oxide dismutase and glutathione peroxidase. The recovery of enzyme status was maximum at the dose of 200 mg/kg body weight and was comparable to irinotecan. Our study reveals that kaempferol could be safely used as a chemopreventive agent in colorectal cancer.

  3. Sensitive amperometric determination of hydrazine using a carbon paste electrode modified with silver-doped zeolite L nanoparticles

    Indian Academy of Sciences (India)

    NEDA SALEK GILANI; SEYED NASER AZIZI; SHAHRAM GHASEMI

    2017-02-01

    Silver-loaded nanozeolite-L-modified carbon paste electrode (Ag/L–CPE) was used as a novel sensing platform for enhanced electrocatalytic oxidation and determination of hydrazine. Zeolite L nanoparticles were synthesized via hydrothermal approach and then characterized using various techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electronic microscopy (SEM) and Brunauer–Emmett–Teller (BET). Silver-exchanged nanozeolite L (Ag/L) was prepared and mixed with carbon paste to prepare the modified electrode. Cyclic voltammetry studies revealed the high performance of Ag/L–CPE for electrocatalytic oxidation of hydrazine. Two linear ranges were detected in the amperometric detection of hydrazine. The first range was from10 $\\mu$M to 0.4 mM with sensitivity of 103.13 $\\mu$A mM$^{−1}$ and the second one was from 0.4 to 4mM with sensitivity of 58.131 $\\mu$A mM$^{−1}$. The response time and detection limit ($S/N = 3$) of this sensor were determined to be 2 s and 1.5 $\\mu$M, respectively. The unique porous structure of nanozeolite L offers a promising catalyst support candidate for efficient electrochemical sensing of hydrazine. The sensor exhibited appreciable repeatability, reproducibility and stability, and was able to detect hydrazine in the presence of even 500-fold excess concentrations of interfering species. Also, the sensor was used to determine hydrazine concentration in water samples with satisfactory results.

  4. Visualising volcanic gas plumes with virtual globes

    Science.gov (United States)

    Wright, T. E.; Burton, M.; Pyle, D. M.; Caltabiano, T.

    2009-09-01

    The recent availability of small, cheap ultraviolet spectrometers has facilitated the rapid deployment of automated networks of scanning instruments at several volcanoes, measuring volcanic SO 2 gas flux at high frequency. These networks open up a range of other applications, including tomographic reconstruction of the gas distribution which is of potential use for both risk mitigation, particularly to air traffic, and environmental impact modelling. Here we present a methodology for visualising reconstructed plumes using virtual globes, such as Google Earth, which allows animations of the evolution of the gas plume to be displayed and easily shared on a common platform. We detail the process used to convert tomographically reconstructed cross-sections into animated gas plume models, describe how this process is automated and present results from the scanning network around Mt. Etna, Sicily. We achieved an average rate of one frame every 12 min, providing a good visual representation of the plume which can be examined from all angles. In creating these models, an approximation to turbulent diffusion in the atmosphere was required. To this end we derived the value of the turbulent diffusion coefficient for quiescent conditions near Etna to be around 200- 500m2s-1.

  5. Detection of contaminant plumes released from landfills

    Science.gov (United States)

    Yenigül, N. B.; Hendsbergen, A. T.; Elfeki, A. M. M.; Dekking, F. M.

    2006-06-01

    Contaminant leaks released from landfills are a significant threat to groundwater quality. The groundwater detection monitoring systems installed in the vicinity of such facilities are vital. In this study the detection probability of a contaminant plume released from a landfill has been investigated by means of both a simulation and an analytical model for both homogeneous and heterogeneous aquifer conditions. The results of the two models are compared for homogeneous aquifer conditions to illustrate the errors that might be encountered with the simulation model. For heterogeneous aquifer conditions contaminant transport is modelled by an analytical model using effective (macro) dispersivities. The results of the analysis show that the simulation model gives the concentration values correctly over most of the plume length for homogeneous aquifer conditions, and that the detection probability of a contaminant plume at given monitoring well locations match quite well. For heterogeneous aquifer conditions the approximating analytical model based on effective (macro) dispersivities yields the average concentration distribution satisfactorily. However, it is insufficient in monitoring system design since the discrepancy between the detection probabilities of contaminant plumes at given monitoring well locations computed by the two models is significant, particularly with high dispersivity and heterogeneity.

  6. Diagnostics of laser ablated plasma plumes

    DEFF Research Database (Denmark)

    Amoruso, S.; Toftmann, B.; Schou, Jørgen;

    2004-01-01

    The effect of an ambient gas on the expansion dynamics of laser ablated plasmas has been studied for two systems by exploiting different diagnostic techniques. First, the dynamics of a MgB2 laser produced plasma plume in an Ar atmosphere has been investigated by space-and time-resolved optical...

  7. Ablation plume dynamics in a background gas

    DEFF Research Database (Denmark)

    Amoruso, Salvatore; Schou, Jørgen; Lunney, James G.

    2010-01-01

    The expansion of a plume in a background gas of pressure comparable to that used in pulsed laser deposition (PLD) has been analyzed in terms of the model of Predtechensky and Mayorov (PM). This approach gives a relatively clear and simple description of the essential hydrodynamics during the expa...

  8. DSMC simulation of Europa water vapor plumes

    Science.gov (United States)

    Berg, J. J.; Goldstein, D. B.; Varghese, P. L.; Trafton, L. M.

    2016-10-01

    A computational investigation of the physics of water vapor plumes on Europa was performed with a focus on characteristics relevant to observation and spacecraft mission operations. The direct simulation Monte Carlo (DSMC) method was used to model the plume expansion assuming a supersonic vent source. The structure of the plume was determined, including the number density, temperature, and velocity fields. The possibility of ice grain growth above the vent was considered and deemed probable for large (diameter > ∼20 m) vents at certain Mach numbers. Additionally, preexisting grains of three diameters (0.1, 1, 50 μm) were included and their trajectories examined. A preliminary study of photodissociation of H2O into OH and H was performed to demonstrate the behavior of daughter species. A set of vent parameters was evaluated including Mach number (Mach 2, 3, 5), reduced temperature as a proxy for flow energy loss to the region surrounding the vent, and mass flow rate. Plume behavior was relatively insensitive to these factors, with the notable exception of mass flow rate. With an assumed mass flow rate of ∼1000 kg/s, a canopy shock occurred and a maximum integrated line of sight column density of ∼1020 H2O molecules/m2 was calculated, comparing favorably with observation (Roth et al., 2014a).

  9. Propagation of light through ship exhaust plumes

    NARCIS (Netherlands)

    Iersel, M. van; Mack, A.; Eijk, A.M.J. van; Schleijpen, H.M.A.

    2014-01-01

    Looking through the atmosphere, it is sometimes difficult to see the details of an object. Effects like scintillation and blur are the cause of these difficulties. Exhaust plumes of e.g. a ship can cause extreme scintillation and blur, making it even harder to see the details of what lies behind the

  10. Plume dynamics in heterogeneous porous media

    Science.gov (United States)

    Neufeld, Jerome A.; Huppert, Herbert E.

    2008-11-01

    Buoyancy driven flows in layered porous media are present in many geological settings and play an important role in the mixing of fluids, from the dispersal of pollutants in underground aquifers to enhanced oil recovery techniques and, of more recent importance, the sequestration of carbon dioxide (CO2). Seismic images of the rise of a buoyant CO2 plume at Sleipner in the North Sea indicate that these plumes are greatly influenced by a vertical array of thin lenses of relatively low permeability material. We model propagation of CO2 at each layer as a gravity current in a porous medium which propagates along, and drains through, a thin, low permeability seal. Drainage, driven both by hydrostatic pressure and the body force on the draining fluid, leads to an initial rapid advance followed by a gradual retreat of the current to a steady-state. By incorporating a vertical array of these single layer models we are able to capture the rise of the buoyant plume in layered reservoirs. We find that the plume is characterized by a broad head with a tail given by the steady state extent.

  11. DSMC simulation of Io's unsteady Tvashtar plume

    Science.gov (United States)

    Hoey, W. A.; Ackley, P. C.; Trafton, L. M.; Goldstein, D. B.; Varghese, P. L.

    2016-11-01

    Jupiter's moon Io supports its rarefied atmosphere with prolific tidally-driven episodic volcanism. Its largest volcanic plumes erupt violently and exhibit intricate structure, their canopies rising to hundreds of km above the Ionian surface. In early 2007, the NASA New Horizons (NH) spacecraft captured the active Tvashtar plume in a time sequence of panchromatic images at high spatial resolution and observed both discrete "filamentary" patterns in the descending particulate structure, and a prominent traveling canopy wave. These are transient and asymmetric features, indicative of Tvashtar's unresolved and complex vent processes. In this work, we introduce a methodology for identifying vent spatial and temporal scales in the rarefied plume. Three-dimensional DSMC simulations of the collisional gas flowfield are combined with a flow-tracking dust particle model, enabling a broad exploration of parameter space in pursuit of the critical frequencies that qualitatively reproduce the dynamical phenomena observed in Tvashtar's collisional canopy and providing insight into the dynamics of transient extra-terrestrial volcanic plumes.

  12. Relative Abundance Measurements in Plumes and Interplumes

    CERN Document Server

    Guennou, Chloé; Savin, Daniel Wolf

    2015-01-01

    We present measurements of relative elemental abundances in plumes and interplumes. Plumes are bright, narrow structures in coronal holes that extend along open magnetic field lines far out into the corona. Previous work has found that in some coronal structures the abundances of elements with a low first ionization potential (FIP) 10 eV). We have used EIS spectroscopic observations made on 2007 March 13 and 14 over an ~24 hour period to characterize abundance variations in plumes and interplumes. To assess their elemental composition, we have used a differential emission measure (DEM) analysis, which accounts for the thermal structure of the observed plasma. We have used lines from ions of iron, silicon, and sulfur. From these we have estimated the ratio of the iron and silicon FIP bias relative to that for sulfur. From the results, we have created FIP-bias-ratio maps. We find that the FIP-bias ratio is sometimes higher in plumes than in interplumes and that this enhancement can be time dependent. These res...

  13. Plume or no Plume, the Case of the Siberian Trap Formation

    Science.gov (United States)

    Reichow, M. K.; Saunders, A. D.; White, R. V.; Al'Mukhamedov, A. I.; Medvedev, A. I.; Inger, S.

    2003-12-01

    The generation mechanism of continental large igneous provinces, such as the Siberian Traps, are matters of recent debate, particularly their relation to mantle plumes derived from the Earth's interior. Alternative models relate the formation of large igneous provinces to bolide impacts or small-scale convection at the boundary of asymmetric lithospheres. Neither of these models is without criticism and each model cannot explain all characteristics of continental flood basalt formation alone. However, strong support for the involvement of a mantle plume comes from the observation that large volumes of basaltic melts ( ˜3 x 106 km3) erupted within a short period of time (pulse of volcanism extruded over large areas of the Siberian craton. Although the major and trace element data are consistent with a plume origin for the Siberian Traps, they cannot prove it; however, magma volume and timing constraints do strongly suggest that a mantle plume was involved in the formation of the Earth's largest continental flood basalt province.

  14. Computational Fluid Dynamic (CFD) analysis of axisymmetric plume and base flow of film/dump cooled rocket nozzle

    Science.gov (United States)

    Tucker, P. K.; Warsi, S. A.

    1993-07-01

    Film/dump cooling a rocket nozzle with fuel rich gas, as in the National Launch System (NLS) Space Transportation Main Engine (STME), adds potential complexities for integrating the engine with the vehicle. The chief concern is that once the film coolant is exhausted from the nozzle, conditions may exist during flight for the fuel-rich film gases to be recirculated to the vehicle base region. The result could be significantly higher base temperatures than would be expected from a regeneratively cooled nozzle. CFD analyses were conduced to augment classical scaling techniques for vehicle base environments. The FDNS code with finite rate chemistry was used to simulate a single, axisymmetric STME plume and the NLS base area. Parallel calculations were made of the Saturn V S-1 C/F1 plume base area flows. The objective was to characterize the plume/freestream shear layer for both vehicles as inputs for scaling the S-C/F1 flight data to NLS/STME conditions. The code was validated on high speed flows with relevant physics. This paper contains the calculations for the NLS/STME plume for the baseline nozzle and a modified nozzle. The modified nozzle was intended to reduce the fuel available for recirculation to the vehicle base region. Plumes for both nozzles were calculated at 10kFT and 50kFT.

  15. The development of a non-cryogenic nitrogen/oxygen supply system. [using hydrazine/water electrolysis

    Science.gov (United States)

    Greenough, B. M.; Mahan, R. E.

    1974-01-01

    A hydrazine/water electrolysis process system module design was fabricated and tested to demonstrate component and module performance. This module is capable of providing both the metabolic oxygen for crew needs and the oxygen and nitrogen for spacecraft leak makeup. The component designs evolved through previous R and D efforts, and were fabricated and tested individually and then were assembled into a complete module which was successfully tested for 1000 hours to demonstrate integration of the individual components. A survey was made of hydrazine sensor technology and a cell math model was derived.

  16. Ultrathin willow-like CuO nanoflakes as an efficient catalyst for electro-oxidation of hydrazine

    Science.gov (United States)

    Ma, Yuanyuan; Li, Hao; Wang, Rongfang; Wang, Hui; Lv, Weizhong; Ji, Shan

    2015-09-01

    In this paper, preparation of ultrathin willow-like CuO nanoflakes via a one-step process was reported. X-ray diffraction pattern showed the formation of monoclinic CuO crystal, which was also confirmed by result of high resolution transmission electron microscopy. Scanning electron microscopy showed that ultrathin willow-like CuO nanoflakes were formed. Catalytic testing indicated that the ultrathin willow-like CuO nanoflakes exhibited high electrocatalytic activity and durability toward the electro-oxidation of hydrazine in alkaline medium. The results suggested that the as-prepared CuO nanoflakes were potential electrode materials for hydrazine fuel cell.

  17. Volcanic Plume Measurements with UAV (Invited)

    Science.gov (United States)

    Shinohara, H.; Kaneko, T.; Ohminato, T.

    2013-12-01

    Volatiles in magmas are the driving force of volcanic eruptions and quantification of volcanic gas flux and composition is important for the volcano monitoring. Recently we developed a portable gas sensor system (Multi-GAS) to quantify the volcanic gas composition by measuring volcanic plumes and obtained volcanic gas compositions of actively degassing volcanoes. As the Multi-GAS measures variation of volcanic gas component concentrations in the pumped air (volcanic plume), we need to bring the apparatus into the volcanic plume. Commonly the observer brings the apparatus to the summit crater by himself but such measurements are not possible under conditions of high risk of volcanic eruption or difficulty to approach the summit due to topography etc. In order to overcome these difficulties, volcanic plume measurements were performed by using manned and unmanned aerial vehicles. The volcanic plume measurements by manned aerial vehicles, however, are also not possible under high risk of eruption. The strict regulation against the modification of the aircraft, such as installing sampling pipes, also causes difficulty due to the high cost. Application of the UAVs for the volcanic plume measurements has a big advantage to avoid these problems. The Multi-GAS consists of IR-CO2 and H2O gas analyzer, SO2-H2O chemical sensors and H2 semiconductor sensor and the total weight ranges 3-6 kg including batteries. The necessary conditions of the UAV for the volcanic plumes measurements with the Multi-GAS are the payloads larger than 3 kg, maximum altitude larger than the plume height and installation of the sampling pipe without contamination of the exhaust gases, as the exhaust gases contain high concentrations of H2, SO2 and CO2. Up to now, three different types of UAVs were applied for the measurements; Kite-plane (Sky Remote) at Miyakejima operated by JMA, Unmanned airplane (Air Photo Service) at Shinomoedake, Kirishima volcano, and Unmanned helicopter (Yamaha) at Sakurajima

  18. Lidar measurements of launch vehicle exhaust plumes

    Science.gov (United States)

    Dao, Phan D.; Curtis, David; Farley, Robert; Soletsky, Philip; Davidson, Gilbert; Gelbwachs, Jerry A.

    1997-10-01

    The Mobile Lidar Trailer (MLT) was developed and operated to characterize launch vehicle exhaust plume and its effects on the environment. Two recent applications of this facility are discussed in this paper. In the first application, the MLT was used to characterize plumes in the stratosphere up to 45 km in support of the Air Force Space and Missile Center's Rocket Impact on Stratospheric Ozone program. Solid rocket motors used by Titan IV and other heavy launch vehicles release large quantities of gaseous hydrochloric acid in the exhaust and cause concerns about a possible depletion of the ozone layer. The MLT was deployed to Cape Canaveral Air Station since October 1995 to monitor ozone and to investigate plume dynamics and properties. Six campaigns have been conducted and more are planned to provide unique data with the objective of addressing the environmental issues. The plume was observed to disperse rapidly into horizontally extended yet surprisingly thin layer with thickness recorded in over 700 lidar profiles to be less than 250 meters. MLT operates with the laser wavelengths of 532, 355 and 308 nm and a scanning receiving telescope. Data on particle backscattering at the three wavelengths suggest a consistent growth of particle size in the 2-3 hour observation sessions following the launch. In the second type of application, the MLT was used as a remote sensor of nitrogen dioxide, a caustic gaseous by-product of common liquid propellant oxidizer. Two campaigns were conducted at the Sol Se Mete Canyon test site in New Mexico in December 1996 an January 1997 to study the dispersion of nitrogen dioxide and rocket plume.

  19. A comparison of the turbulent entrainment process in line plumes and wall plumes

    Science.gov (United States)

    Parker, David; Burridge, Henry; Partridge, Jamie; Linden, Paul

    2016-11-01

    Flows driven by sources of buoyancy appear in a large number of geophysical and industrial applications. The process of turbulent entrainment in these flows is key to understanding how they evolve and how one might model them. It has been observed that the entrainment is reduced when a line source of buoyancy is positioned immediately adjacent to a wall. To gain insight into the effect of the wall on the entrainment process we perform simultaneous PIV and LIF on both line plumes, in the absence of any boundary, and when the source is adjacent to a vertical boundary forming a wall plume. The experiments are designed to isolate the effect of the wall by using the same experimental setup and parameters for both flows with the addition of the wall and half the buoyancy flux used in the wall plume case. Of particular interest is the effect the large scale eddies, forming at the edge of the plume and engulfing ambient fluid, have on the entrainment process. By using velocity statistics in a coordinate system based on the instantaneous scalar edge of the plume, a technique we have recently used to analyse similar effects in an axisymmetric plume, the significance of this large scale engulfment will be quantified.

  20. Experimental and Numerical Study of Spacecraft Contamination Problems Associated With Gas and Gas-Droplet Thruster Plume Flows

    Science.gov (United States)

    2006-04-17

    solution and the right-hand side K(T,Tv) are functions of two variables); 65 • ill-posedness and nonuniqueness of the solution (this issue will be...investigation on plume contamination and surface effects. FTR Univ. Hamburg TRI-ESA-1987. 4. SUMMARY All research engineering and technical...component nozzle flow (model validation),” Proc. European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS 2004

  1. The role of ions in the formation and evolution of particles in aircraft plumes

    Science.gov (United States)

    Yu, Fangqun; Turco, Richard P.

    We consider the effects on aircraft plume microphysics of ions generated by chemiionization processes within the engine combustors. Ions provide centers around which molecular clusters rapidly coalesce, thus promoting the formation of electrically charged sulfuric acid/water aerosols. The resulting charged micro-particles exhibit enhanced growth due to condensation and coagulation aided by electrostatic effects. Simulations with a plume microphysics code show that volatile particles observed behind aircraft may be explained by such processes, as long as initial ion concentrations in the exhaust exceed ˜108/cm³. This analysis also suggests that the primary emissions of sulfuric acid (plus sulfur trioxide) should amount to at least 20-30% of the fuel sulfur to explain the observed number of volatile particles >9 nm in diameter. Ionized plume simulations reveal a distinct bimodal aerosol distribution, in which an “ion” mode constitutes the larger “activated” volatile sulfuric acid particles, while a smaller “neutral” mode comprises the residual slowly-growing neutral molecular clusters formed in the highly supersaturated region of the plume.

  2. Meiotic changes in Vicia faba L. subsequent to treatments of hydrazine hydrate and maleic hydrazide

    Directory of Open Access Journals (Sweden)

    Shaheen Husain

    2013-01-01

    Full Text Available Assessing the impact of mutagens for creating variations in crops like faba bean (Vicia faba L. is an important criterion in the contemporary world where food insecurity and malnutrition is alarming at the doors of various nations. Impact of two chemical mutagens viz. hydrazine hydrate (HZ and maleic hydrazide (MH on the two varieties (NDF-1 and HB-405 of Vicia faba were analysed in terms of meiotic behavior and pollen sterility. Since there are not enough data about the effect of these mutagens on the chromosomal behaviors of Vicia faba, this study presents the role of hydrazine hydrate and maleic hydrazide as well as various types of chromosomal aberrations in crop improvement. The lower concentration of mutagens showed less pollen sterility compared to the higher concentrations. Manipulation of plant structural component to induce desirable alternations provides valuable material for the breeders and could be used favorably for increasing mutation rate and obtaining a desirable spectrum of mutation in faba beans based on preliminary studies of cell division.

  3. Investigation of the collision line broadening problem as applicable to the NASA Optical Plume Anomaly Detection (OPAD) system, phase 1

    Science.gov (United States)

    Dean, Timothy C.; Ventrice, Carl A.

    1995-05-01

    As a final report for phase 1 of the project, the researchers are submitting to the Tennessee Tech Office of Research the following two papers (reprinted in this report): 'Collision Line Broadening Effects on Spectrometric Data from the Optical Plume Anomaly System (OPAD),' presented at the 30th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 27-29 June 1994, and 'Calculation of Collision Cross Sections for Atomic Line Broadening in the Plume of the Space Shuttle Main Engine (SSME),' presented at the IEEE Southeastcon '95, 26-29 March 1995. These papers fully state the problem and the progress made up to the end of NASA Fiscal Year 1994. The NASA OPAD system was devised to predict concentrations of anomalous species in the plume of the Space Shuttle Main Engine (SSME) through analysis of spectrometric data. The self absorption of the radiation of these plume anomalies is highly dependent on the line shape of the atomic transition of interest. The Collision Line Broadening paper discusses the methods used to predict line shapes of atomic transitions in the environment of a rocket plume. The Voigt profile is used as the line shape factor since both Doppler and collisional line broadening are significant. Methods used to determine the collisional cross sections are discussed and the results are given and compared with experimental data. These collisional cross sections are then incorporated into the current self absorbing radiative model and the predicted spectrum is compared to actual spectral data collected from the Stennis Space Center Diagnostic Test Facility rocket engine. The second paper included in this report investigates an analytical method for determining the cross sections for collision line broadening by molecular perturbers, using effective central force interaction potentials. These cross sections are determined for several atomic species with H2, one of the principal constituents of the SSME plume environment, and compared with experimental data.

  4. Plume collimation for laser ablation electrospray ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Vertes, Akos; Stolee, Jessica A.

    2016-06-07

    In various embodiments, a device may generally comprise a capillary having a first end and a second end; a laser to emit energy at a sample in the capillary to ablate the sample and generate an ablation plume in the capillary; an electrospray apparatus to generate an electrospray plume to intercept the ablation plume to produce ions; and a mass spectrometer having an ion transfer inlet to capture the ions. The ablation plume may comprise a collimated ablation plume. The device may comprise a flow cytometer. Methods of making and using the same are also described.

  5. Plume collimation for laser ablation electrospray ionization mass spectrometry

    Science.gov (United States)

    Vertes, Akos; Stolee, Jessica A.

    2016-06-07

    In various embodiments, a device may generally comprise a capillary having a first end and a second end; a laser to emit energy at a sample in the capillary to ablate the sample and generate an ablation plume in the capillary; an electrospray apparatus to generate an electrospray plume to intercept the ablation plume to produce ions; and a mass spectrometer having an ion transfer inlet to capture the ions. The ablation plume may comprise a collimated ablation plume. The device may comprise a flow cytometer. Methods of making and using the same are also described.

  6. Plume collimation for laser ablation electrospray ionization mass spectrometry

    Science.gov (United States)

    Vertes, Akos; Stolee, Jessica A.

    2014-09-09

    In various embodiments, a device may generally comprise a capillary having a first end and a second end; a laser to emit energy at a sample in the capillary to ablate the sample and generate an ablation plume in the capillary; an electrospray apparatus to generate an electrospray plume to intercept the ablation plume to produce ions; and a mass spectrometer having an ion transfer inlet to capture the ions. The ablation plume may comprise a collimated ablation plume. The device may comprise a flow cytometer. Methods of making and using the same are also described.

  7. Crystal structures of nitrato-(2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo) aquacopper and chloro-(2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo) copper

    Energy Technology Data Exchange (ETDEWEB)

    Chumakov, Yu. M. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Paholnitcaia, A. Yu. [State University of Moldova (Moldova, Republic of); Petrenko, P. A. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Tsapkov, V. I., E-mail: vtsapkov@gmail.com [State University of Moldova (Moldova, Republic of); Poirier, D. [Centre Hospitalier Universitaire de Quebec (Canada); Gulea, A. P. [State University of Moldova (Moldova, Republic of)

    2015-01-15

    Two crystal modifications of nitrato-(2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo) aquacopper (I and II) and two modifications of chloro-(2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo) copper (III and IV) have been synthesized and studied by X-ray diffraction. In structures I and II, the copper atoms coordinate a monodeprotonated molecule of the organic ligand, nitrate ions, and a water molecule. In crystals of I, the complexes are monomeric, whereas complexes II are linked via nitrate ions to form polymeric chains. In both structures the coordination polyhedron of the copper atom can be described as a distorted tetragonal bipyramid—(4 + 1 + 1) in I and (4 + 2) in II. These coordination polyherdra have different compositions. In structures III and IV, the metal atoms coordinate a monodeprotonated (2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazole molecule and chloride ions. In III the complex-forming ion has square-planar coordination geometry, whereas structure IV consists of centrosymmetric dimers with two bridging chlorine atoms. It was found that nitrato-(2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo) aquacopper possesses antitumor activity.

  8. Sol-gel process preparation and evaluation of the analytical performances of an hydrazine specific chemical sensor; Preparation par procede sol-gel et evaluation des performances analytiques d`un capteur chimique specifique de l`hydrazine

    Energy Technology Data Exchange (ETDEWEB)

    Gojon, C

    1996-12-01

    The realisation of optical fibers active chemical collector to analyze hydrazine in line, in the spent fuel reprocessing process is the subject of this work. The p.dimethyl-amino-benzaldehyde has been chosen as reagent for its chemical and optical properties. 186 refs.

  9. Crystal structures of nitrato-{2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo}aquacopper and chloro-{2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo}copper

    Science.gov (United States)

    Chumakov, Yu. M.; Paholnitcaia, A. Yu.; Petrenko, P. A.; Tsapkov, V. I.; Poirier, D.; Gulea, A. P.

    2015-01-01

    Two crystal modifications of nitrato-{2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo}aquacopper ( I and II) and two modifications of chloro-{2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo}copper ( III and IV) have been synthesized and studied by X-ray diffraction. In structures I and II, the copper atoms coordinate a monodeprotonated molecule of the organic ligand, nitrate ions, and a water molecule. In crystals of I, the complexes are monomeric, whereas complexes II are linked via nitrate ions to form polymeric chains. In both structures the coordination polyhedron of the copper atom can be described as a distorted tetragonal bipyramid—(4 + 1 + 1) in I and (4 + 2) in II. These coordination polyherdra have different compositions. In structures III and IV, the metal atoms coordinate a monodeprotonated {2-[2-phenyl(pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazole molecule and chloride ions. In III the complex-forming ion has square-planar coordination geometry, whereas structure IV consists of centrosymmetric dimers with two bridging chlorine atoms. It was found that nitrato-{2-[2-(1-pyridine-2-ylethylidene)hydrazine]-1,3-benzothiazolo}aquacopper possesses antitumor activity.

  10. Plume meander and dispersion in a stable boundary layer

    Science.gov (United States)

    Hiscox, April L.; Miller, David R.; Nappo, Carmen J.

    2010-11-01

    Continuous lidar measurements of elevated plume dispersion and corresponding micrometeorology data are analyzed to establish the relationship between plume behavior and nocturnal boundary layer dynamics. Contrasting nights of data from the JORNADA field campaign in the New Mexico desert are analyzed. The aerosol lidar measurements were used to separate the plume diffusion (plume spread) from plume meander (displacement). Mutiresolution decomposition was used to separate the turbulence scale (90 s). Durations of turbulent kinetic energy stationarity and the wind steadiness were used to characterize the local scale and submesoscale turbulence. Plume meander, driven by submesoscale wind motions, was responsible for most of the total horizontal plume dispersion in weak and variable winds and strong stability. This proportion was reduced in high winds (i.e., >4 m s-1), weakly stable conditions but remained the dominant dispersion mechanism. The remainder of the plume dispersion in all cases was accounted for by internal spread of the plume, which is a small eddy diffusion process driven by turbulence. Turbulence stationarity and the wind steadiness are demonstrated to be closely related to plume diffusion and plume meander, respectively.

  11. Investigation of the direct and indirect electrochemical oxidation of hydrazine in nitric acid medium on platinum; Etude de l`oxydation electrochimique directe et indirecte de l`hydrazine en milieu acide nitrique sur platine

    Energy Technology Data Exchange (ETDEWEB)

    Cames, B

    1997-12-31

    In nuclear fuel processing by the PUREX process, the purification of plutonium in nitric acid medium requires the oxidation of Pu(III) to Pu(IV), and of hydrazinium nitrate to nitrogen. The study helped to characterize the electrochemical behavior of the oxidation of hydrazinium nitrate and the reduction of nitric acid to nitrous acid, a compound which can chemically oxidize hydrazinium nitrate and Pu(III). Electro-analytical studies on polycrystalline platinum showed that hydrazine is oxidized in two potential zones, which depend on the surface texture of the platinum anode. Electrolysis in separate compartments, carried out in medium-acid media (2 and 4 mo/l) in the potential zone where these processes take place, showed that, at 0.9 V/ECS, the hydrazine oxidation reactions involved are: a four-electron process (75 %) with nitrogen formation and a one-electron process (25 %) with formation of nitrogen and ammonium ion. By contrast, electrolysis carried out at 0.65 V/ECS (with reactivation of the electrode at - 0.2 V/ECS to remove the poison from the platinum) allowed the selective oxidation of hydrazine to nitrogen by the four-electron reaction. Nitric acid can only be reduced to nitrous acid in the absence of hydrazine. For medium-acid media ({<=} 6 mol/l), this reaction takes place at potentials below - 0.2 V/ECS. However, the production rate of nitrous acid (partial order 0 with respect to nitric acid) is very low compared with the values obtained for strongly-acid media (6 to 10 mol/l) at the potential of - 0.1 V/ECS. Note that, in concentrated nitric medium, the selectivity of the reduction reaction is 47 to 85 % for nitrous acid, depending on the nitric acid concentration (6 to 10 mol/l) and the potential imposed (- 0.1 {<=} E {<=} 0.6 V/ECS). A kinetic study helped to determine the hydrazine oxidation rates as a function of the operating conditions. In all cases, the reaction rate is of partial order 0 with respect to hydrazine. These studies accordingly

  12. Engine Test Stand Design Constraints Expert System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Propulsion test stands are designed for thermal and pressure loads for certain classes of engines. These plume induced loads are: radiative heating, acoustics and...

  13. Adsorption of hydrazine on the perfect and defective copper (111) surface: A dispersion-corrected DFT study

    NARCIS (Netherlands)

    Tafreshi, Saeedeh S.; Roldan, Alberto; Dzade, Nelson Y.; de Leeuw, Nora H.

    2014-01-01

    We have investigated the adsorption of hydrazine (N2H4) on perfect and defect-containing copper (111) surfaces by first-principles calculations. The long-range interactions are included in the geometry optimization through the application of the generalised gradient approximation with dispersion cor

  14. In situ synthesis of ceria nanoparticles in the ordered mesoporous carbon as a novel electrochemical sensor for the determination of hydrazine

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yue [College of Chemistry, Nankai University, 94 WeiJin Road, Tianjin 300071 (China); Li, Yijun, E-mail: yijunli@nankai.edu.cn [Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300071 (China); College of Chemistry, Nankai University, 94 WeiJin Road, Tianjin 300071 (China); He, Xiwen [College of Chemistry, Nankai University, 94 WeiJin Road, Tianjin 300071 (China)

    2014-03-01

    Highlights: • CeO{sub 2}–OMC composites were prepared via a hydrothermal method. • CeO{sub 2}–OMC had electrocatalytic ability to oxidation of hydrazine. • The sensor had high sensitivity, excellent stability and reproducibility. • The sensor was successfully employed to detect hydrazine in real water samples. - Abstract: A novel ceria (CeO{sub 2})–ordered mesoporous carbon (OMC) modified electrode for the sensitive amperometric determination of hydrazine was reported. CeO{sub 2}–OMC composites were synthesized via a hydrothermal method at a relatively low temperature (180 °C) and characterized by scanning electron microscopy (SEM), transmission electron microcopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The CeO{sub 2}–OMC modified glassy carbon electrode was characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) and indicated good electrocatalytic effect to the oxidation of hydrazine. Under the optimized conditions, the present sensor could be used to measure hydrazine in wide linear range from 40 nM to 192 μM (R{sup 2} = 0.999) with a low detection limit of 12 nM (S/N = 3). Additionally, the sensor has been successfully applied to detect hydrazine in real water samples and the recoveries were between 98.2% and 105.6%. Eventually, the sensor exhibited an excellent stability and reproducibility as a promising method for determination of hydrazine.

  15. Flows in Sunspot Plumes Detected with SOHO

    CERN Document Server

    Brynildsen, N; Brekke, P; Fredvik, T; Haugan, S V H; Kjeldseth-Moe, O; Wikstøl, O

    1998-01-01

    Bright EUV sunspot plumes have been observed in eight out of eleven different sunspot regions with the Coronal Diagnostic Spectrometer -- CDS on SOHO. From wavelength shifts we derive the line-of-sight velocity, relative to the average velocity in the rastered area, 120 arcsec x 120 arcsec. In sunspot plumes we find that the motion is directed away from the observer and increases with increasing line formation temperature, reaches a maximum between 15 and 41 km~s$^{-1}$ close to log T $\\approx$ 5.5, then decreases abruptly. The flow field in the corona is not well correlated with the flow in the transition region and we discuss briefly the implication of this finding.

  16. Plume RF interference calculations for space shuttle

    Science.gov (United States)

    Boynton, F. P.; Rajasekhar, P. S.

    1978-01-01

    During a static ground test of a full-scale SRM, measurements of attenuation of the UHF 416.5 MHz Range Safety Signal, the VHF voice link (230 MHz), and of S-band (c. 2.2. GHz) communications links were undertaken. Analyses of these results indicate that measurable attenuation did occur at all test frequencies. The measured attenuation levels are compared with a simple model in which the received signal is identified as that diffracted about the edge of the highly absorbing plume and the signal level in the shadow zone is evaluated using the formula for diffraction at a straight edge. The comparison is satisfactory at VHF and UHF frequencies, and slightly less so at S-band. Reasons for the discrepancies found at higher frequencies are discussed. A revised procedure which appears to relieve the accuracy problem was developed. This procedure is discussed along with applications to high altitude SRM plume attenuation.

  17. Electric Propulsion Plume Simulations Using Parallel Computer

    Directory of Open Access Journals (Sweden)

    Joseph Wang

    2007-01-01

    Full Text Available A parallel, three-dimensional electrostatic PIC code is developed for large-scale electric propulsion simulations using parallel supercomputers. This code uses a newly developed immersed-finite-element particle-in-cell (IFE-PIC algorithm designed to handle complex boundary conditions accurately while maintaining the computational speed of the standard PIC code. Domain decomposition is used in both field solve and particle push to divide the computation among processors. Two simulations studies are presented to demonstrate the capability of the code. The first is a full particle simulation of near-thruster plume using real ion to electron mass ratio. The second is a high-resolution simulation of multiple ion thruster plume interactions for a realistic spacecraft using a domain enclosing the entire solar array panel. Performance benchmarks show that the IFE-PIC achieves a high parallel efficiency of ≥ 90%

  18. Cruise Ship Plume Tracking Survey Report

    Science.gov (United States)

    2002-09-01

    The U. S. Environmental Protection Agency (EPA) is developing a Cruise Ship Discharge Assessment Report in response to a petition the agency received in March 2000. The petition requested that EPA assess and where necessary control discharges from cruise ships. Comments received during public hearings, in 2000, resulted in the EPA agreeing to conduct a survey to assess the discharge plumes resulting from cruise ships, operating in ocean waters off the Florida coast and to compare the results to the Alaska dispersion models. This survey report describes the daily activities of August 2001 Cruise Ship Plume Tracking Survey, and provides a synopsis of the observations from the survey. It also provides data that can be used to assess dispersion of cruise ship wastewater discharges, while in transit. A description of the survey methods is provided in Section 2. Survey results are presented in Section 3. Findings and conclusions are discussed in Section 4.

  19. Sub-Grid Scale Plume Modeling

    Directory of Open Access Journals (Sweden)

    Greg Yarwood

    2011-08-01

    Full Text Available Multi-pollutant chemical transport models (CTMs are being routinely used to predict the impacts of emission controls on the concentrations and deposition of primary and secondary pollutants. While these models have a fairly comprehensive treatment of the governing atmospheric processes, they are unable to correctly represent processes that occur at very fine scales, such as the near-source transport and chemistry of emissions from elevated point sources, because of their relatively coarse horizontal resolution. Several different approaches have been used to address this limitation, such as using fine grids, adaptive grids, hybrid modeling, or an embedded sub-grid scale plume model, i.e., plume-in-grid (PinG modeling. In this paper, we first discuss the relative merits of these various approaches used to resolve sub-grid scale effects in grid models, and then focus on PinG modeling which has been very effective in addressing the problems listed above. We start with a history and review of PinG modeling from its initial applications for ozone modeling in the Urban Airshed Model (UAM in the early 1980s using a relatively simple plume model, to more sophisticated and state-of-the-science plume models, that include a full treatment of gas-phase, aerosol, and cloud chemistry, embedded in contemporary models such as CMAQ, CAMx, and WRF-Chem. We present examples of some typical results from PinG modeling for a variety of applications, discuss the implications of PinG on model predictions of source attribution, and discuss possible future developments and applications for PinG modeling.

  20. Plume Comparisons between Segmented Channel Hall Thrusters

    Science.gov (United States)

    Niemack, Michael; Staack, David; Raitses, Yevgeny; Fisch, Nathaniel

    2001-10-01

    Angular ion flux plume measurements were taken in several configurations of segmented channel Hall thrusters. The configurations differed by the placement of relatively short rings made from materials with different conductive and secondary electron emission properties along the boron nitride ceramic channel of the thrusters (these have been shown to affect the plume [1]). The ion fluxes are compared with ion trajectory simulations based on plasma potential data acquired with a high speed emissive probe [2]. Preliminary results indicate that in addition to the physical properties of the segments, the plume angle can be strongly affected by the placement of segmented rings relative to the external and internal walls of the channel. [1] Y. Raitses, L. Dorf, A. Litvak and N. J. Fisch, Journal of Applied Physics 88, 1263, 2000 [2] D. Staack, Y. Raitses, N. J. Fisch, Parametric Investigations of Langmuir Probe Induced Perturbations in a Hall Thruster, DPP01 Poster Presentation This work was supported by the U.S. DOE Contract No. DE-ACO2-76-CHO3073.

  1. Monitoring and forecasting Etna volcanic plumes

    Directory of Open Access Journals (Sweden)

    S. Scollo

    2009-09-01

    Full Text Available In this paper we describe the results of a project ongoing at the Istituto Nazionale di Geofisica e Vulcanologia (INGV. The objective is to develop and implement a system for monitoring and forecasting volcanic plumes of Etna. Monitoring is based at present by multispectral infrared measurements from the Spin Enhanced Visible and Infrared Imager on board the Meteosat Second Generation geosynchronous satellite, visual and thermal cameras, and three radar disdrometers able to detect ash dispersal and fallout. Forecasting is performed by using automatic procedures for: i downloading weather forecast data from meteorological mesoscale models; ii running models of tephra dispersal, iii plotting hazard maps of volcanic ash dispersal and deposition for certain scenarios and, iv publishing the results on a web-site dedicated to the Italian Civil Protection. Simulations are based on eruptive scenarios obtained by analysing field data collected after the end of recent Etna eruptions. Forecasting is, hence, supported by plume observations carried out by the monitoring system. The system was tested on some explosive events occurred during 2006 and 2007 successfully. The potentiality use of monitoring and forecasting Etna volcanic plumes, in a way to prevent threats to aviation from volcanic ash, is finally discussed.

  2. Gaskinetic Modeling on Dilute Gaseous Plume Impingement Flows

    Directory of Open Access Journals (Sweden)

    Chunpei Cai

    2016-12-01

    Full Text Available This paper briefly reviews recent work on gaseous plume impingement flows. As the major part of this paper, also included are new comprehensive studies on high-speed, collisionless, gaseous, circular jet impinging on a three-dimensional, inclined, diffuse or specular flat plate. Gaskinetic theories are adopted to study the problems, and several crucial geometry-location and velocity-direction relations are used. The final complete results include impingement surface properties such as pressure, shear stress, and heat flux. From these surface properties, averaged coefficients of pressure, friction, heat flux, moment over the entire flat plate, and the distance from the moment center to the flat plate center are obtained. The final results include accurate integrations involving the geometry and specific speed ratios, inclination angle, and the temperature ratio. Several numerical simulations with the direct simulation Monte Carlo method validate these analytical results, and the results are essentially identical. The gaskinetic method and processes are heuristic and can be used to investigate other external high Knudsen (Kn number impingement flow problems, including the flow field and surface properties for a high Knudsen number jet from an exit and flat plate of arbitrary shapes. The results are expected to find many engineering applications, especially in aerospace and space engineering.

  3. Evidence for Little Shallow Entrainment in Starting Mantle Plumes

    Science.gov (United States)

    Lohmann, F. C.; Phipps Morgan, J.; Hort, M.

    2005-12-01

    Basalts from intraplate or hotspot ocean islands show distinct geochemical signatures. Their diversity in composition is generally believed to result from the upwelling plume entraining shallow mantle material during ascent, while potentially also entraining other deep regions of the mantle. Here we present results from analogue laboratory experiments and numerical modelling that there is evidence for little shallow entrainment into ascending mantle plumes, i.e. most of the plume signature is inherited from the source. We conducted laboratory experiments using glucose syrup contaminated with glass beads to visualize fluid flow and origin. The plume is initiated by heating from below or by injecting hot, uncontaminated syrup. Particle movement is captured by a CCD camera. In our numerical experiments we solve the Stokes equations for a viscous fluid at infinite Prandtl number with passive tracer particles being used to track fluid flow and entrainment rates, simulating laboratory as well as mantle conditions. In both analogue experiments and numerical models we observe the classical plume structure being embedded in a `sheath' of material from the plume source region that retains little of the original temperature anomaly of the plume source. Yet, this sheath ascends in the `slipstream' of the plume at speeds close to the ascent speed of the plume head, and effectively prevents the entrainment of surrounding material into the plume head or plume tail. We find that the source region is most effectively sampled by an ascending plume and that compositional variations in the source region are preserved during plume ascent. The plume center and plume sheath combined are composed of up to 85% source material. However, there is also evidence of significant entrainment of up to 30% of surrounding material into the outer layers of the plume sheath. Entrainment rates are found to be influenced by mantle composition and structure, with the radial viscosity profile of the

  4. Lunar maria - result of mantle plume activity?

    Science.gov (United States)

    Sharkov, E.

    It is generally accepted that lunar maria are the result of catastrophic impact events. However, comparative studying of the Earth's and the Moon's tectonomagmatic evolution could evidence about another way of these specific structures origin. Such studies showed that the both planetary bodies evolved on the close scenario: their geological development began after solidification of global magmatic oceans which led to appearance of their primordial crusts: granitic on the Earth and anorthositic - on the Moon. The further evolution of the both bodies occurred in two stages. For their first stages, lasted ˜2.5 mlrd. years on the Earth and ˜1.5 mlrd. years on the Moon, were typical melts, generated in depleted mantle (Bogatikov et al., 2000). However, at the boundary 2.2-2.0 Ga ago on the Earth and 3.9-3.8 Ga on the Moon another type of magmas appeared: geochemical enriched Fe-Ti picrites and basalts, characteristic for the terrestrial Phanerozoic plume-related situations, and basaltic mare magmatism with high-Ti varieties on the Moon. It suggests that evolution of the Earth's magmatism was linked with ascending of mantle plumes (superplumes) of two generation: (1) generated in the mantle, depleted during solidification of magmatic ocean and Archean magmatic activity, and (2) generated at the core-mantle boundary (CMB). The latter were enriched in the mantle fluid components (Fe, Ti, alkalies, etc); this lighter material could ascend to shallower depths, leading to change of tectonic processes, in particular, to appearance of plate tectonics as the major type of tectonomagmatic activity till now (Bogatikov et al., 2000). By analogy to the Earth, magmatism of the Moon was also linked with ascending of mantle plumes: (1) generated in the depleted mantle (magnesian suite) and (2) generated at the lunar CMB with liquid at that time metallic core (mare basalt and picrites with high-Ti varieties). Like on the Earth, these plumes were lighter than the older plumes, and

  5. Liquid phase synthesis: preparation of co microspheres by hydrazine reducing method

    Science.gov (United States)

    Deng, Y.; Lu, Z. Q.; Xie, F.; Liang, H.; Wang, Y. J.; Du, X. H.

    2017-01-01

    The study synthesizes Co microspheres with perfect spherical shape by use hydrazine hydrate as reducing agent to reduce CoCl2 in alkaline conditions at room temperature, the influence of NaOH addition amount on crystal morphology and structure of cobalt particle were studied. The results show that, under the condition of concentration of NaOH, 0.030g ml-1 and having ethylene glycol as solvent, are the best choice to synthesize Co microspheres, and the grain is smaller, suitable for industrial production. At the condition of less amount of NaOH, cobalt particle's surface is smooth spherical, and with the increase of NaOH, particles will deviate from the spherical morphology and the surface become rough. The first section in your paper

  6. A simple hydrazine based molecule for selective detection of Fluoride ion in DMSO

    Indian Academy of Sciences (India)

    ADDITI ROY CHOWDHURY; PRIYABRATA BANERJEE

    2017-04-01

    A newly synthesized hydrazine-functionalized Schiff base chemoreceptor [N¹N³−bis(4-cyanobenzylidene) isophthalahydrazide], NBCBIH has been prepared and successfully utilized for selective detection of Fluoride ion. Herein, NH and C=N-like functional units have been incorporated which providebetter colorimetric response compared to systems where such kind of units are absent. On exposure to F⁻, NBCBIH turns from almost colorless to yellow. The recognition is well-supported by UV-Vis, fluorescence and ¹H-NMR in DMSO. The fluorescence quenching is well-explained by photoinduced electron transfer mechanism (PET). The limit of detection of F− with NBCBIH is 0.7 × 10⁻⁴M.

  7. Theoretical Studies of Structure, Spectroscopy, and Properties of a New Hydrazine Derivative

    Directory of Open Access Journals (Sweden)

    Hajar Sahebalzamani

    2013-01-01

    Full Text Available We will report a combined experimental and theoretical study on molecular structure, vibrational spectra, and energies of (E-1-(2,4-dinitrophenyl-2-[(4-methylphenylmethylidene]hydrazine (1. The molecular geometry and vibrational frequencies and energies in the ground state are calculated by using HF and DFT levels of theory with 6-311G basis sets. The calculated HOMO and LUMO energies also confirm that charge transfer occurs within the molecule. The harmonic vibrational frequencies were calculated, and the scaled values have been compared with experimental FTIR and FT-Raman spectra. The observed and the calculated frequencies are found to be in good agreement. The experimental spectra also coincide satisfactorily with those of theoretically constructed bar-type spectrograms.

  8. Cubic Copper Hexacyanoferrates Nanoparticles: Facile Template-Free Deposition and Electrocatalytic Sensing Towards Hydrazine

    Directory of Open Access Journals (Sweden)

    Xingxing Wang

    2011-01-01

    Full Text Available Cubic copper hexacyanoferrate (CuHCF nanoparticles prepared via electrolytic deposition are presented with their morphology and crystalline structure characterized with SEM and XRD. The advantage of this methodology is that it allows the fabrication of uniform cubic nanoparticles with permeable structures onto the desired underlying electrode substrate. It was observed that the CuHCF film acts as a permeable membrane for cations such as K+, Na+, Li+, and NH4+ with a selection order of K+> Li+>NH4+> Na+. Furthermore, the analytical utility of these cubic-like CuHCF morphologies supported on a glassy carbon electrode was evaluated towards the electrochemical oxidation of hydrazine which was found to exhibit a linear response over the range 66 M to 17 mM with a detection limit corresponding to 16.5 M.

  9. Superior supercapacitor electrode material from hydrazine hydrate modified porous polyacrylonitrile fiber

    Science.gov (United States)

    Li, Ying; Lu, Chunxiang; Wang, Junzhong; Yan, Hua; Zhang, Shouchun

    2016-03-01

    A hierarchical porous carbon fiber with high nitrogen doping was fabricated for high-performance supercapacitor. For the purpose of high nitrogen retention, the porous polyacrylonitrile fiber was treated by hydrazine hydrate, and then underwent pre-oxidation, carbonization, and activation in sequence. The resulted material exhibited high nitrogen content of 7.82 at.%, large specific surface area of 1963.3m2 g-1, total pore volume of 1.523cm3 g-1, and the pores with size range of 1-4nm were account for 49.1%. Due to these features, the high reversible capacitance of 415F g-1 and the good performance in heavy load discharge were obtained. In addition, the amazing cyclability was observed after 10,000 circles without capacitance fading.

  10. Local charge transport properties of hydrazine reduced monolayer graphene oxide sheets prepared under pressure condition

    DEFF Research Database (Denmark)

    Ryuzaki, Sou; Meyer, Jakob Abild Stengaard; Petersen, Søren Vermehren

    2014-01-01

    Charge transport properties of chemically reduced graphene oxide (RGO) sheets prepared by treatment with hydrazine were examined using conductive atomic force microscopy. The current-voltage (I-V) characteristics of monolayer RGO sheets prepared under atmospheric pressure followed an exponentially...... increase due to 2D variable-range hopping conduction through small graphene domains in an RGO sheet containing defect regions of residual sp3carbon clusters bonded to oxygen groups, whereas RGO sheets prepared in a closed container under moderate pressure showed linear I-V characteristics...... with a conductivity of 267.2-537.5S/m. It was found that the chemical reduction under pressure results in larger graphene domains (sp2networks) in the RGO sheets when compared to that prepared under atmospheric pressure, indicating that the present reduction of GO sheets under the pressure is one of the effective...

  11. Template-free Synthesis of One-dimensional Cobalt Nanostructures by Hydrazine Reduction Route

    Directory of Open Access Journals (Sweden)

    Lan Tianmin

    2011-01-01

    Full Text Available Abstract One-dimensional cobalt nanostructures with large aspect ratio up to 450 have been prepared via a template-free hydrazine reduction route under external magnetic field assistance. The morphology and properties of cobalt nanostructures were characterized by scanning electron microscopy, X-ray diffractometer, and vibrating sample magnetometer. The roles of the reaction conditions such as temperature, concentration, and pH value on morphology and magnetic properties of fabricated Co nanostructures were investigated. This work presents a simple, low-cost, environment-friendly, and large-scale production approach to fabricate one-dimensional magnetic Co materials. The resulting materials may have potential applications in nanodevice, catalytic agent, and magnetic recording.

  12. Chemosensing ability of hydroxynaphthylidene derivatives of hydrazine towards Cu2+: Experimental and computational studies

    Indian Academy of Sciences (India)

    Jayaraman Dessingiou; Jayshree K Khedkar; Chebrolu P Rao

    2014-07-01

    2-Hydroxynaphthylidene derivatives of hydrazine, namely L1, L2 and L3, were synthesized by going through two-step reactions and the products were characterized. The ion recognition properties of these receptors were studied using fluorescence and absorption spectroscopy. The receptors were found to be sensitive and selective towards Cu2+ in methanol solution among the 13 metal ions studied, namely Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Pb2+, Na+, K+, Ca2+ and Mg2+, by exhibiting switch off fluorescence. The stoichiometry of the complexed species was found to be 2:1. The fluorescence quenching with Cu2+ is in the order of L1 > L2 > L3. These conjugates were also found to act as colorimetric sensors for Cu2+ in solution by exhibiting visual colour change. The 2:1 complex shows a centrosymmetric structure based on DFT computations.

  13. Precursor combustion synthesis of nanocrystalline cobalt substituted nickel zinc ferrites from hydrazinated mixed metal fumarates

    Energy Technology Data Exchange (ETDEWEB)

    Gawas, S.G.; Verenkar, V.M.S., E-mail: vmsv@rediffmail.com

    2015-04-10

    Highlights: • Convenient synthesis of hydrazinated mixed metal fumarates under nitrogen atmosphere. • Six hydrazine molecules in precursor provide high exothermicity for the decomposition. • Autocatalytic decomposition of precursors helps in ferritization at 410 °C. • Single domain-superparamagnetic particles of uniform size in the range of 15–30 nm. - Abstract: In present investigation, a systematic approach towards synthesis of nanocrystalline ferrites, Co{sub x}Ni{sub 0.6−x}Zn{sub 0.4}Fe{sub 2}O{sub 4} (x = 0.1 and 0.4) has been reported by room temperature decomposition of precursors, Co{sub x}Ni{sub 0.6−x}Zn{sub 0.4}Fe{sub 2} (C{sub 4}H{sub 2}O{sub 4}){sub 3}·6N{sub 2}H{sub 4} (x = 0.1 and 0.4). The precursor complexes were characterized by Fourier transform infrared spectroscopy (FTIR), chemical analysis and thermal studies like isothermal mass loss, total mass loss, thermogravimetry (TG), derivative of thermogravimetry (DTG) and differential thermal analysis (DTA). The TG–DTG–DTA patterns of both precursors reveal multistep decomposition with complete ferritization at 410 °C. The thermally decomposed products were characterized by X-ray diffractometry (XRD) for phase purity. The FT-IR spectroscopy studies of the same shows complete removal of all organic moieties from decomposed precursors. The nanophasic nature of synthesized ferrites was confirmed by transmission electron microscopy (TEM) analysis as well as from broadening of XRD peaks. The AC magnetization studies show the existence of single domain and superparamagnetic particles, which supports nanosize particles distribution in the ferrite system under study.

  14. Experimental study of oil plume stability: Parametric dependences and optimization.

    Science.gov (United States)

    Li, Haoshuai; Shen, Tiantian; Bao, Mutai

    2016-10-15

    Oil plume is known to interact with density layer in spilled oil. Previous studies mainly focused on tracking oil plumes and predicting their impact on marine environment. Here, simulated experiments are presented that investigated the conditions inducing the formation of oil plume, focusing especially on the effects of oil/water volume ratio, oil/dispersant volume rate, ambient stratification and optimal conditions of oil plume on determining whether a plume will trap or escape. Scenario simulations showed that OWR influences the residence time most, dispersants dosage comes second and salinity least. The optimum residence time starts from 2387s, occurred at approximately condition (OWR, 0.1, DOR, 25.53% and salinity, 32.38). No change in the relative distribution under the more scale tank was observed, indicating these provide the time evolution of the oil plumes.

  15. Life Cycle of Mantle Plumes: A perspective from the Galapagos Plume (Invited)

    Science.gov (United States)

    Gazel, E.; Herzberg, C. T.

    2009-12-01

    Hotspots are localized sources of heat and magmatism considered as modern-day evidence of mantle plumes. Some hotspots are related to massive magmatic production that generated Large Igneous Provinces (LIPS), an initial-peak phase of plume activity with a mantle source hotter and more magmatically productive than present-day hotspots. Geological mapping and geochronological studies have shown much lower eruption rates for OIB compared to lavas from Large Igneous Provinces LIPS such as oceanic plateaus and continental flood provinces. Our study is the first quantitative petrological comparison of mantle source temperatures and extent of melting for OIB and LIP sources. The wide range of primary magma compositions and inferred mantle potential temperatures for each LIP and OIB occurrence suggest that this rocks originated form a hotspot, a spatially localized source of heat and magmatism restricted in time. Extensive outcrops of basalt, picrite, and sometimes komatiite with circa 65-95 Ma ages occupy portions of the pacific shore of Central and South America included in the Caribbean Large Igneous Province (CLIP). There is general consensus of a Pacific-origin of CLIP and most studies suggest that it was produced by melting in the Galapagos mantle plume. The Galapagos connection is consistent with isotopic and geochemical similarities with lavas from the present-day Galapagos hotspot. A Galapagos link for rocks in South American oceanic complexes (eg. the island of Gorgona) is more controversial and requires future work. The MgO and FeO contents of lavas from the Galapagos related lavas and their primary magmas have decreased since the Cretaceous. From petrological modeling we infer that these changes reflect a cooling of the Galapagos mantle plume from a potential temperature of 1560-1620 C in the Cretaceous to 1500 C at the present time. These temperatures are higher than 1350 C for ambient mantle associated with oceanic ridges, and provide support for the mantle

  16. Plume tectonics and cratons formation in the early Earth

    Science.gov (United States)

    Gerya, T.; Stern, R. J.; Baes, M.; Fischer, R.; Sizova, E.; Sobolev, S. V.; Whattam, S. A.

    2015-12-01

    Modern geodynamics and continental growth are critically driven by subduction and plate tectonics, however how this tectonic regime started and what geodynamic regime was before remains controversial. Most present-day subduction initiation mechanisms require acting plate forces and/or pre-existing zones of lithospheric weakness, which are themselves the consequence of plate tectonics. Here, we focus on plume-lithosphere interactions and spontaneous plume-induced subduction initiation, which does not require pre-existing lithospheric fabric and is viable for both stagnant lid and mobile/deformable lid conditions. We present results of 2D and 3D numerical modeling of plume-induced deformation and associated crustal growth resulting from tectono-magmatic interaction of ascending mantle plumes with oceanic-type lithosphere. We demonstrate that weakening of the lithosphere by plume-induced magmatism is the key factor allowing for its internal deformation and differentiation resulting in continental crust growth. We also show that plume-lithosphere interaction can enable subduction and rudimentary plate tectonics initiation at the margins of a crustal plateau growing above the plume head. We argue that frequent plume-arc interactions recorded in Archean crust could reflect either short-term plume-induced subduction or plume-induced episodic lithospheric drips. We furthermore suggest a distinct plume-tectonics regime operated on Earth before plate tectonics, which was associated with widespread tectono-magmatic heat and mass exchange between the crust and the mantle. This regime was characterized by weak deformable plates with low topography, massive juvenile crust production from mantle derived melts, mantle-flows-driven crustal deformation, magma-assisted crustal convection and widespread development of lithospheric delamination and crustal drips. Plume tectonics also resulted in growth of hot depleted chemically buoyant subcrustal proto-cratonic mantle layer. Later

  17. Marine bird aggregations associated with the tidally-driven plume and plume fronts of the Columbia River

    Science.gov (United States)

    Zamon, Jeannette E.; Phillips, Elizabeth M.; Guy, Troy J.

    2014-09-01

    Freshwater discharge from large rivers into the coastal ocean creates tidally-driven frontal systems known to enhance mixing, primary production, and secondary production. Many authors suggest that tidal plume fronts increase energy flow to fish-eating predators by attracting planktivorous fishes to feed on plankton aggregated by the fronts. However, few studies of plume fronts directly examine piscivorous predator response to plume fronts. Our work examined densities of piscivorous seabirds relative to the plume region and plume fronts of the Columbia River, USA. Common murres (Uria aalge) and sooty shearwaters (Puffinus griseus) composed 83% of all birds detected on mesoscale surveys of the Washington and Oregon coasts (June 2003-2006), and 91.3% of all birds detected on fine scale surveys of the plume region less than 40 km from the river mouth (May 2003 and 2006). Mesoscale comparisons showed consistently more predators in the central plume area compared to the surrounding marine area (murres: 10.1-21.5 vs. 3.4-8.2 birds km-2; shearwaters: 24.2-75.1 vs. 11.8-25.9 birds km-2). Fine scale comparisons showed that murre density in 2003 and shearwater density in both 2003 and 2006 were significantly elevated in the tidal plume region composed of the most recently discharged river water. Murres tended to be more abundant on the north face of the plume. In May 2003, more murres and shearwaters were found within 3 km of the front on any given transect, although maximum bird density was not necessarily found in the same location as the front itself. Predator density on a given transect was not correlated with frontal strength in either year. The high bird densities we observed associated with the tidal plume demonstrate that the turbid Columbia River plume does not necessarily provide fish with refuge from visual predators. Bird predation in the plume region may therefore impact early marine survival of Pacific salmon (Oncorhynchus spp.), which must migrate through the

  18. AQUEOUS N-HETEROCYCLIZATION OF PRIMARY AMINES AND HYDRAZINES WITH DIHALIDES: MICROWAVE-ASSISTED SYNTHESES OF N-AZACYCLOALKANES, ISOINDOLE, PYRAZOLE, PYRAZOLIDINE AND PHTHALAZINE DERIVATIVES

    Science.gov (United States)

    The synthesis of nitrogen-containing heterocycles from alkyl dihalides (ditosylates) and primary amines and hydrazines via a simple and efficient cyclocondensation in alkaline aqueous medium that occurs under microwave irradiation is described. This improved greener synthetic met...

  19. Algorithms and analysis for underwater vehicle plume tracing.

    Energy Technology Data Exchange (ETDEWEB)

    Byrne, Raymond Harry; Savage, Elizabeth L. (Texas A& M University, College Station, TX); Hurtado, John Edward (Texas A& M University, College Station, TX); Eskridge, Steven E.

    2003-07-01

    The goal of this research was to develop and demonstrate cooperative 3-D plume tracing algorithms for miniature autonomous underwater vehicles. Applications for this technology include Lost Asset and Survivor Location Systems (L-SALS) and Ship-in-Port Patrol and Protection (SP3). This research was a joint effort that included Nekton Research, LLC, Sandia National Laboratories, and Texas A&M University. Nekton Research developed the miniature autonomous underwater vehicles while Sandia and Texas A&M developed the 3-D plume tracing algorithms. This report describes the plume tracing algorithm and presents test results from successful underwater testing with pseudo-plume sources.

  20. An infrared method for plume rise visualization and measurement

    Science.gov (United States)

    Rickel, Cindy; Lamb, Brian; Guenther, Alex; Allwine, Eugene

    An infrared video camera and recording system were used to record near source plume rise from a low turbine stack at an oil gathering center at Prudhoe Bay, AK. The system provided real-time, continuous visualization of the plume using a color monitor while the images were recorded with a standard video tape recorder. Following the field study, single frame images were digitized using a micro-computer video system. As part of the digitization, the plume centerline was determined as well as an isotherm of the plume outline. In this application, one frame from each 2-min period in the record was digitized. The results were used to calculate the variability in plume centerline during each hour. During strong winds with blowing snow, the mean plume rise for the hour at 15 m downwind was 6±2 m. The observed plume rise from the turbine stack was greater than that calculated using momentum-only or buoyancy-only plume rise models and only slightly larger than that estimated from combined momentum-buoyancy plume rise models.

  1. Field experimental observations of highly graded sediment plumes

    DEFF Research Database (Denmark)

    Hjelmager Jensen, Jacob; Saremi, Sina; Jimenez, Carlos;

    2015-01-01

    A field experiment in the waters off the south-eastern coast of Cyprus was carried out to study near-field formation of sediment plumes from dumping. Different loads of sediment were poured into calm and limpid waters one at the time from just above the sea surface. The associated plumes, gravita......A field experiment in the waters off the south-eastern coast of Cyprus was carried out to study near-field formation of sediment plumes from dumping. Different loads of sediment were poured into calm and limpid waters one at the time from just above the sea surface. The associated plumes...

  2. Turbulence and Mixing in the Columbia River Plume

    Science.gov (United States)

    Kilcher, L. F.; Nash, J.; Moum, J.

    2004-12-01

    Thin bouyant plumes represent a technical challenge for in-situ observations. In July 2004 a unique set of measurements were taken in which our vertical microstructure profiler, Chameleon, and acoustics (300 kHz ADCP and 120 kHz echosounder) were modified to measure the O(1-5 m) thick plume. The Chameleon profiles included measurements of density, fluorescence, optical backscatter and turbulent energy dissipation. Intense turbulence was observed in plume fronts (with 30 m vertical displacements), at the plume base (with O(1 s-1) shear) and in O(20 m) thick bottom boundary layers. Preliminary results from 10 days of observations will be presented and discussed.

  3. Nanostructured SnO{sub 2} encapsulated guar-gum hybrid nanocomposites for electrocatalytic determination of hydrazine

    Energy Technology Data Exchange (ETDEWEB)

    Malik, Priya [Department of Applied Chemistry & Polymer Technology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042 (India); Srivastava, Manish [Department of Physics & Astrophysics, University of Delhi, Delhi 110007 (India); Verma, Ranjana [Solar Energy Material Laboratory, Department of Energy, Tezpur University, Tezpur, Assam 784 028 (India); Kumar, Manish [Department of Applied Chemistry & Polymer Technology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042 (India); Kumar, D., E-mail: dkumar@dce.ac.in [Department of Applied Chemistry & Polymer Technology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042 (India); Singh, Jay, E-mail: jay_singh143@yahoo.co.in [Department of Applied Chemistry & Polymer Technology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042 (India)

    2016-01-01

    The present article deals with synthesis of sol–gel derived tin dioxide (SnO{sub 2}) nanoparticles encapsulated in to guar gum (GG) biopolymer as the organic–inorganic hybrid materials for the determination of hydrazine. The organic–inorganic hybrid combines the perfunctory strength offered by the inorganic SnO{sub 2} nanoparticles with flexible binding sites provided by the organic biopolymer (GG) solution by the ultrasonication. The phase identification, crystalline size, surface morphology and optical properties of prepared SnO{sub 2} and SnO{sub 2}-GG nanocomposites has been investigated through FT-IR, XRD, SEM, AFM, TEM, UV–Vis, and PL techniques. The colloidal solution of SnO{sub 2} and GG is electrophoretically deposited (EPD) onto the indium tin-oxide (ITO) glass substrate and studied for the electrooxidation of hydrazine. Under the optimized experimental conditions, the linearity between the current response and the hydrazine concentration has been obtained in the range of 2–22 mM, with a low detection limit of 2.76 mM and a high sensitivity of 5.72 μA cm{sup −2}. Based on the linear increase in amperometric current, a sensitive hydrazine electrochemical sensor is constructed. The proposed SnO{sub 2}-GG/ITO electrode shows a good response time (35 s), reproducibility, and long-term stability. The obtained results suggest that SnO{sub 2}-GG nanocomposites electrode provides a favorable sensing platform for the electrochemical studies. In addition, the cyclic voltammetry (CV) studies are used to evaluate the kinetic parameters. - Graphical abstract: Synthesis of sol–gel derived tin dioxide (SnO{sub 2}) nanoparticles grafted in to gaur gum (GG) organic–inorganic hybrid nanocomposite for determination of hydrazine (HZ). Under optimized experimental conditions, SnO{sub 2}-GG/ITO electrode shows, linearity 2–22 mM, and detection limit 2.769 mM with high sensitivity of 5.72 μA cm{sup −2}. The results clearly suggest that SnO{sub 2}-GG

  4. Transport of nitrogen in a treated-wastewater plume to coastal discharge areas, Ashumet Valley, Cape Cod, Massachusetts

    Science.gov (United States)

    Barbaro, Jeffrey R.; Walter, Donald A.; LeBlanc, Denis R.

    2013-01-01

    Land disposal of treated wastewater from a treatment plant on the Massachusetts Military Reservation in operation from 1936 to 1995 has created a plume of contaminated groundwater that is migrating toward coastal discharge areas in the town of Falmouth, Massachusetts. To develop a better understanding of the potential impact of the treated-wastewater plume on coastal discharge areas, the U.S. Geological Survey, in cooperation with the Air Force Center for Engineering and the Environment, evaluated the fate of nitrogen (N) in the plume. Groundwater samples from two large sampling events in 1994 and 2007 were used to map the size and location of the plume, calculate the masses of nitrate-N and ammonium-N, evaluate changes in mass since cessation of disposal in 1995, and create a gridded dataset suitable for use in nitrogen-transport simulations. In 2007, the treated-wastewater plume was about 1,200 meters (m) wide, 30 m thick, and 7,700 m long and contained approximately 87,000 kilograms (kg) nitrate-N and 31,600 kg total ammonium-N. An analysis of previous studies and data from 1994 and 2007 sampling events suggests that most of biologically reactive nitrogen in the plume in 2007 will be transported to coastal discharge areas as either nitrate or ammonium with relatively little transformation to an environmentally nonreactive end product such as nitrogen gas. Nitrogen-transport simulations were conducted with a previously calibrated regional three-dimensional MODFLOW groundwater flow model. Mass-loaded particle tracking was used to simulate the advective transport of nitrogen to discharge areas (or receptors) along the coast. In the simulations, nonreactive transport (no mass loss in the aquifer) was assumed, providing an upper-end estimate of nitrogen loads to receptors. Simulations indicate that approximately 95 percent of the nitrate-N and 99 percent of the ammonium-N in the wastewater plume will eventually discharge to the Coonamessett River, Backus River, Green

  5. Quantification of Plume-Soil Interaction and Excavation Due to the Sky Crane Descent Stage

    Science.gov (United States)

    Vizcaino, Jeffrey; Mehta, Manish

    2015-01-01

    The quantification of the particulate erosion that occurs as a result of a rocket exhaust plume impinging on soil during extraterrestrial landings is critical for future robotic and human lander mission design. The aerodynamic environment that results from the reflected plumes results in dust lifting, site alteration and saltation, all of which create a potentially erosive and contaminant heavy environment for the lander vehicle and any surrounding structures. The Mars Science Lab (MSL), weighing nearly one metric ton, required higher levels of thrust from its retro propulsive systems and an entirely new descent system to minimize these effects. In this work we seek to quantify plume soil interaction and its resultant soil erosion caused by the MSL's Sky Crane descent stage engines by performing three dimensional digital terrain and elevation mapping of the Curiosity rover's landing site. Analysis of plume soil interaction altitude and time was performed by detailed examination of the Mars Descent Imager (MARDI) still frames and reconstructed inertial measurement unit (IMU) sensor data. Results show initial plume soil interaction from the Sky Crane's eight engines began at ground elevations greater than 60 meters and more than 25 seconds before the rovers' touchdown event. During this time, viscous shear erosion (VSE) was dominant typically resulting in dusting of the surface with flow propagating nearly parallel to the surface. As the vehicle descended and decreased to four powered engines plume-plume and plume soil interaction increased the overall erosion rate at the surface. Visibility was greatly reduced at a height of roughly 20 meters above the surface and fell to zero ground visibility shortly after. The deployment phase of the Sky Crane descent stage hovering at nearly six meters above the surface showed the greatest amount of erosion with several large particles of soil being kicked up, recirculated, and impacting the bottom of the rover chassis. Image

  6. Flows in Sunspot Plumes Detected with SOHO

    Science.gov (United States)

    Brynildsen, N.; Maltby, P.; Brekke, P.; Fredvik, T.; Haugan, S. V. H.; Kjeldseth-Moe, O.; Wikstol, O.

    1998-09-01

    In the Letter, ``Flows in Sunspot Plumes Detected with the Solar and Heliospheric Observatory'' by N. Brynildsen, P. Maltby, P. Brekke, T. Fredvik, S. V. H. Haugan, O. Kjeldseth-Moe, and Ø. Wikstøl (ApJ, 502, L85 [1998]), the following correction should be made: In the last line on page L86, which reads ``peak line intensity I>=5 are located (1) above the umbra or, '' an ``Ī'' should be inserted so that the revised line reads ``peak line intensity I>=5Ī are located (1) above the umbra or.''

  7. Restudy of the Ground Vibrational State of Hydrazine Using the Generalized IAM-like Treatment for the Amino-Wagging Tunneling Motion.

    Science.gov (United States)

    Pyka, Jan; Ohashi, Nobukimi

    2001-05-01

    The amino-wagging tunneling process in hydrazine was treated using the generalized IAM-like method developed by Hougen and Coudert, and Hamiltonian matrix elements were derived for each symmetry species in the combined group-theoretical and IAM-like treatment. Ground state microwave absorption transition data of hydrazine were least squares analyzed again in this treatment to determine axis switching angles for the amino-wagging tunneling process. Copyright 2001 Academic Press.

  8. Multiple dopant injection system for small rocket engines

    Science.gov (United States)

    Sakala, G. G.; Raines, N. G.

    1992-07-01

    The Diagnostics Test Facility (DTF) at NASA's Stennis Space Center (SSC) was designed and built to provide a standard rocket engine exhaust plume for use in the research and development of engine health monitoring instrumentation. A 1000 lb thrust class liquid oxygen (LOX)-gaseous hydrogen (GH2) fueled rocket engine is used as the subscale plume source to simulate the SSME during experimentation and instrument development. The ability of the DTF to provide efficient, and low cost test operations makes it uniquely suited for plume diagnostic experimentation. The most unique feature of the DTF is the Multiple Dopant Injection System (MDIS) that is used to seed the exhaust plume with the desired element or metal alloy. The dopant injection takes place at the fuel injector, yielding a very uniform and homogeneous distribution of the seeding material in the exhaust plume. The MDIS allows during a single test firing of the DTF, the seeding of the exhaust plume with up to three different dopants and also provides distilled water base lines between the dopants. A number of plume diagnostic-related experiments have already utilized the unique capabilities of the DTF.

  9. Channelization of plumes beneath ice shelves

    KAUST Repository

    Dallaston, M. C.

    2015-11-11

    © 2015 Cambridge University Press. We study a simplified model of ice-ocean interaction beneath a floating ice shelf, and investigate the possibility for channels to form in the ice shelf base due to spatial variations in conditions at the grounding line. The model combines an extensional thin-film description of viscous ice flow in the shelf, with melting at its base driven by a turbulent ocean plume. Small transverse perturbations to the one-dimensional steady state are considered, driven either by ice thickness or subglacial discharge variations across the grounding line. Either forcing leads to the growth of channels downstream, with melting driven by locally enhanced ocean velocities, and thus heat transfer. Narrow channels are smoothed out due to turbulent mixing in the ocean plume, leading to a preferred wavelength for channel growth. In the absence of perturbations at the grounding line, linear stability analysis suggests that the one-dimensional state is stable to initial perturbations, chiefly due to the background ice advection.

  10. Intercontinental transport of nitrogen oxide pollution plumes

    Directory of Open Access Journals (Sweden)

    M. Wenig

    2003-01-01

    Full Text Available We describe the first satellite observation of intercontinental transport of nitrogen oxides emitted by power plants, verified by simulations with a particle tracer model. The analysis of such episodes shows that anthropogenic NOx plumes may influence the atmospheric chemistry thousands of kilometers away from its origin, as well as the ocean they traverse due to nitrogen fertilization. This kind of monitoring became possible by applying an improved algorithm to extract the tropospheric fraction of NO2 from the spectral data coming from the GOME instrument. As an example we show the observation of NO2 in the time period 4--14 May, 1998, from the South African Plateau to Australia which was possible due to favourable weather conditions during that time period which availed the satellite measurement. This episode was also simulated with the Lagrangian particle dispersion model FLEXPART which uses NOx emissions taken from an inventory for industrial emissions in South Africa and is driven with analyses from the European Centre for Medium-Range Weather Forecasts. Additionally lightning emissions were taken into account by utilizing Lightning Imaging Sensor data. Lightning was found to contribute probably not more than 25% of the resulting concentrations. Both, the measured and simulated emission plume show matching patterns while traversing the Indian Ocean to Australia and show great resemblance to the aerosol and CO2 transport observed by Piketh et al. (2000.

  11. Global Circulation and Impact of Plasmaspheric Plumes

    Science.gov (United States)

    Moore, Thomas E.; Fok, Mei-Ching; Chen, Sheng-Hsiem; Delcourt, Dominique C.; Fedder, Joel A.; Slinker, Steven P.

    2008-01-01

    We report results from the global circulation model of Lyon, Fedder, and Mobarry with an embedded model of the inner magnetosphere including the plasmasphere. The combination is used to initiate large numbers of representative protons on the geosynchronous orbit L shell, to assign particle weightings, to track their: subsequent trajectories in the 3D fields. This permits us to study the global circulation of plasmaspheric plumes and to compare these with Polar observations from the dayside magnetopause region . A range of events is studied from an isolated period of SBz in the solar wind,to a large storm sequence. We consider effects on circulating plasma reaching the dayside reconnection X-line, the population of the plasma sheet with ionospheric protons and the generation of ring current pressure from this source, compared with solar wind, polar wind, and auroral wind sources. We find that the transient plasmaspheric plume source is large in terms of total fluence, but of modest proportions in terms of contribution to the ring current. Implications of this and other results for improved space weather modeling and prediction will be discussed.

  12. Use of activated enol ethers in the synthesis of pyrazoles: reactions with hydrazine and a study of pyrazole tautomerism

    Directory of Open Access Journals (Sweden)

    Denisa Tarabová

    2014-04-01

    Full Text Available Activated enol ethers derived from esters or the dinitrile of malonic acid, or from pentane-2,4-dione were treated with hydrazine hydrate. The structures of the obtained products – pyrazoles 5 – were studied with a focus on tautomerism and supramolecular structure. A reverse addition of the reagents led to the isolation of two novel products, namely bis-enehydrazines 6 with an unsymmetrical arrangement of the formally equivalent subunits.

  13. Effects of Methanol, Methylamine, Formate, N, N-Dimethylhydroxylamine and Formaldehyde on Determining the Methyl Hydrazine Concentration Using Paradime Thylaminobenzaldehyde

    Institute of Scientific and Technical Information of China (English)

    LI; Chuan-bo; CAO; Zhi; BIAN; Xiao-yan; XIAN; Liang; YAN; Tai-hong; ZHENG; Wei-fang

    2012-01-01

    <正>To make sure the feasibility of determining the concentrations of methyl hydrazine (MMH) in 1BP and 2BP using paradime thylaminobenzaldehyde. Researches were done to measure the effects of methanol, methylamine, formate, N, N-dimethylhydroxylamine (DMHAN) and formaldehyde on the method. Though paradime thylaminobenzaldehyde took place condensation reaction with methanol and methylamine, the resultant’s absorbance was zero in 470 nm. So methanol and methylamine did not affect the method of determing the MMH by paradime thylaminobenzaldehyde.

  14. N'-[5-(4-Nitro-phen-yl)furan-2-yl-methyl-idene]-N,N-diphenyl-hydrazine.

    Science.gov (United States)

    Mendoza, Angel; Cabrera-Vivas, Blanca M; Meléndrez-Luevano, Ruth; Pacheco-Álvarez, Teresa; Carranza, Vladimir

    2010-07-17

    The title compound, C(23)H(17)N(3)O(3), has an E configuration with respect to the C=N bond. The dihedral angle between the two phenyl rings bonded to the hydrazine group is 86.45 (13)°. The furan ring makes dihedral angles of 3.4 (2) and 7.06 (13)°, respectively, with the methyl-idenehydrazine C=N-N plane and the benzene ring.

  15. Reduction of Sulphur-containing Aromatic Nitro Compounds with Hydrazine Hydrate over Iron(Ⅲ) Oxide-MgO Catalyst

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Sulphur-containing aromatic amines were prepared efficiently in good to excellent yields by reduction of the corresponding sulphur-containing aromatic nitro compounds with hydrazine hydrate in the presence of iron(Ⅲ) oxide-MgO catalyst. The catalyst exhibited high activity and stability for the reduction of sulphur-containing aromatic nitro compounds. The yields of sulphur-containing aromatic amines were up to 91-99 % at 355 K after reduction for 1-4 h over this catalyst.

  16. A simulation method of aircraft plumes for real-time imaging

    Science.gov (United States)

    Li, Ni; Lv, Zhenhua; Huai, Wenqin; Gong, Guanghong

    2016-07-01

    Real-time infrared simulation technology can provide a large number of infrared images under different conditions to support the design, test and evaluation of a system having infrared imaging equipment with very low costs. By synthesizing heat transfer, infrared physics, fluid mechanics and computer graphics, a real-time infrared simulation method is proposed based on the method of characteristics to predict the infrared feature of aircraft plumes, which tries to obtain a good balance between simulation precision and computation efficiency. The temperature and pressure distribution in the under-expansion status can be rapidly solved with dynamically changing flight statuses and engine working states. And a modified C-G (Curtis-Godson) spectral band model that combines the plume streamlines with the conventional C-G spectral band model was implemented to calculate the non-uniformly distributed radiation parameters inside a plume field. The simulation result was analyzed and compared with the CFD++, which validates the credibility and efficiency of the proposed simulation method.

  17. Converging Supergranular Flows and the Formation of Coronal Plumes

    Science.gov (United States)

    Wang, Y.-M.; Warren, H. P.; Muglach, K.

    2016-01-01

    Earlier studies have suggested that coronal plumes are energized by magnetic reconnection between unipolar flux concentrations and nearby bipoles, even though magnetograms sometimes show very little minority-polarity flux near the footpoints of plumes. Here we use high-resolution extreme-ultraviolet (EUV) images and magnetograms from the Solar Dynamics Observatory (SDO) to clarify the relationship between plume emission and the underlying photospheric field. We find that plumes form where unipolar network elements inside coronal holes converge to form dense clumps, and fade as the clumps disperse again. The converging flows also carry internetwork fields of both polarities. Although the minority-polarity flux is sometimes barely visible in the magnetograms, the corresponding EUV images almost invariably show loop-like features in the core of the plumes, with the fine structure changing on timescales of minutes or less. We conclude that the SDO observations are consistent with a model in which plume emission originates from interchange reconnection in converging flows, with the plume lifetime being determined by the approximately 1-day evolutionary timescale of the supergranular network. Furthermore, the presence of large EUV bright points and/or ephemeral regions is not a necessary precondition for the formation of plumes, which can be energized even by the weak, mixed-polarity internetwork fields swept up by converging flows.

  18. Ocean outfall plume characterization using an Autonomous Underwater Vehicle.

    Science.gov (United States)

    Rogowski, Peter; Terrill, Eric; Otero, Mark; Hazard, Lisa; Middleton, William

    2013-01-01

    A monitoring mission to map and characterize the Point Loma Ocean Outfall (PLOO) wastewater plume using an Autonomous Underwater Vehicle (AUV) was performed on 3 March 2011. The mobility of an AUV provides a significant advantage in surveying discharge plumes over traditional cast-based methods, and when combined with optical and oceanographic sensors, provides a capability for both detecting plumes and assessing their mixing in the near and far-fields. Unique to this study is the measurement of Colored Dissolved Organic Matter (CDOM) in the discharge plume and its application for quantitative estimates of the plume's dilution. AUV mission planning methodologies for discharge plume sampling, plume characterization using onboard optical sensors, and comparison of observational data to model results are presented. The results suggest that even under variable oceanic conditions, properly planned missions for AUVs equipped with an optical CDOM sensor in addition to traditional oceanographic sensors, can accurately characterize and track ocean outfall plumes at higher resolutions than cast-based techniques.

  19. Identification of mantle plumes in the Emeishan Large Igneous Province

    Institute of Scientific and Technical Information of China (English)

    Yi-Gang Xu; Jifeng Xu; Yue-Jun Wang; Bin He; Xiaolong Huang; Zhenyu Luo; Sun-Lin Chung; Long Xiao; Dan Zhu; Hui Shao; Wei-Ming Fan

    2007-01-01

    @@ The plume hypothesis has been recently challengedlargely because some fundamental aspects predicted bythe modeling of plumes are found to be lacking in someclassic hotspot regions. This review paper summarizesrecent achievements made in the late Permian Emeishan continental flood basalt province in southwest China.

  20. CONVERGING SUPERGRANULAR FLOWS AND THE FORMATION OF CORONAL PLUMES

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.-M.; Warren, H. P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Muglach, K., E-mail: yi.wang@nrl.navy.mil, E-mail: harry.warren@nrl.navy.mil, E-mail: karin.muglach@nasa.gov [Code 674, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2016-02-20

    Earlier studies have suggested that coronal plumes are energized by magnetic reconnection between unipolar flux concentrations and nearby bipoles, even though magnetograms sometimes show very little minority-polarity flux near the footpoints of plumes. Here we use high-resolution extreme-ultraviolet (EUV) images and magnetograms from the Solar Dynamics Observatory (SDO) to clarify the relationship between plume emission and the underlying photospheric field. We find that plumes form where unipolar network elements inside coronal holes converge to form dense clumps, and fade as the clumps disperse again. The converging flows also carry internetwork fields of both polarities. Although the minority-polarity flux is sometimes barely visible in the magnetograms, the corresponding EUV images almost invariably show loop-like features in the core of the plumes, with the fine structure changing on timescales of minutes or less. We conclude that the SDO observations are consistent with a model in which plume emission originates from interchange reconnection in converging flows, with the plume lifetime being determined by the ∼1 day evolutionary timescale of the supergranular network. Furthermore, the presence of large EUV bright points and/or ephemeral regions is not a necessary precondition for the formation of plumes, which can be energized even by the weak, mixed-polarity internetwork fields swept up by converging flows.

  1. Effects of ambient turbulence on a particle plume

    Science.gov (United States)

    Lai, Adrian C. H.; Er, J. W.; Law, Adrian W. K.; Adams, E. Eric

    2015-11-01

    We investigated experimentally the effects of ambient turbulence on a particle plume. Homogeneous and isotropic turbulent ambient water was generated by a random jet array in a glass tank. Glass beads of different particle diameters were released continuously into this turbulent ambient using a submerged hourglass, forming particle plumes with a constant efflux velocity; different initial velocities were tested for each particle size. We focused on the region in which the integral length scale of the ambient eddies is larger than that of the particle plume size. Following the arguments of Hunt (1994) and the observation of Hubner (2004) on a single-phase plume, it is expected that in this region, the internal structure or Lagrangian spreading of the particle plume, will not be significantly affected, but the plume centerline would meander due to the ambient turbulence leading to an increase in the Eulerian width. In the presentation, first, we will present our preliminary experimental data which showed that this is also true for two-phase particle plumes. Second, based on this observation, we developed a theoretical framework using a stochastic approach to predict the spreading of the plume. Predictions of the model will be compared with our experimental data. This research was supported by the National Research Foundation Singapore through the Singapore MIT Alliance for Research and Technology's Center for Environmental Sensing and Modeling interdisciplinary research program.

  2. The Structure of Enceladus' Plume from Cassini Occultation Observations

    Science.gov (United States)

    Hansen, C. J.; Esposito, L. W.; Buffington, B. B.; Colwell, J.; Hendrix, A. R.; Meinke, B. K.; Shemansky, D. E.; Stewart, I.; West, R. A.

    2011-12-01

    Cassini's Ultraviolet Imaging Spectrograph (UVIS) has observed 2 stellar and one solar occultation by Enceladus' water vapor plume. These observations have established that water is the primary constituent of the plume, allowed us to calculate the flux of water coming from the plume, and detected super-sonic jets of gas imbedded within the plume [1]. On 19 October 2011 two stars (epsilon and zeta Orionis) will simultaneously be occulted by the plume, and the signal of the two will be in separate pixels on the detector. This is a tangential occultation that will provide a horizontal cut through the plume at two altitudes. The two stars are separated by 24 mrad, or ~20 km, with the lower altitude star 18 km above the limb at its closest point. The groundtrack is similar to the 2010 solar occultation, but viewed from the other side of the plume. Results from this new data set with implications for the vertical structure of the plume and jets will be presented.

  3. Laboratory-Scale Simulation of Spiral Plumes in the Mantle

    CERN Document Server

    Sharifulin, A N

    2012-01-01

    On the basis of laboratory simulation a mechanism is established for the formation of the upper mantle convection spiral plumes from a hot point in the presence of a roll-type large-scale convective flow. The observed plume has horizontal sections near the upper limit, which may lead to the formation of chains of volcanic islands.

  4. Noble metal-free hydrazine fuel cell catalysts: EPOC effect in competing chemical and electrochemical reaction pathways.

    Science.gov (United States)

    Sanabria-Chinchilla, Jean; Asazawa, Koichiro; Sakamoto, Tomokazu; Yamada, Koji; Tanaka, Hirohisa; Strasser, Peter

    2011-04-13

    We report the discovery of a highly active Ni-Co alloy electrocatalyst for the oxidation of hydrazine (N(2)H(4)) and provide evidence for competing electrochemical (faradaic) and chemical (nonfaradaic) reaction pathways. The electrochemical conversion of hydrazine on catalytic surfaces in fuel cells is of great scientific and technological interest, because it offers multiple redox states, complex reaction pathways, and significantly more favorable energy and power densities compared to hydrogen fuel. Structure-reactivity relations of a Ni(60)Co(40) alloy electrocatalyst are presented with a 6-fold increase in catalytic N(2)H(4) oxidation activity over today's benchmark catalysts. We further study the mechanistic pathways of the catalytic N(2)H(4) conversion as function of the applied electrode potential using differentially pumped electrochemical mass spectrometry (DEMS). At positive overpotentials, N(2)H(4) is electrooxidized into nitrogen consuming hydroxide ions, which is the fuel cell-relevant faradaic reaction pathway. In parallel, N(2)H(4) decomposes chemically into molecular nitrogen and hydrogen over a broad range of electrode potentials. The electroless chemical decomposition rate was controlled by the electrode potential, suggesting a rare example of a liquid-phase electrochemical promotion effect of a chemical catalytic reaction ("EPOC"). The coexisting electrocatalytic (faradaic) and heterogeneous catalytic (electroless, nonfaradaic) reaction pathways have important implications for the efficiency of hydrazine fuel cells. © 2011 American Chemical Society

  5. Comparative studies on single-layer reduced graphene oxide films obtained by electrochemical reduction and hydrazine vapor reduction

    Science.gov (United States)

    Wang, Zhijuan; Wu, Shixin; Zhang, Juan; Chen, Peng; Yang, Guocheng; Zhou, Xiaozhu; Zhang, Qichun; Yan, Qingyu; Zhang, Hua

    2012-02-01

    The comparison between two kinds of single-layer reduced graphene oxide (rGO) sheets, obtained by reduction of graphene oxide (GO) with the electrochemical method and hydrazine vapor reduction, referred to as E-rGO and C-rGO, respectively, is systematically studied. Although there is no morphology difference between the E-rGO and C-rGO films adsorbed on solid substrates observed by AFM, the reduction process to obtain the E-rGO and C-rGO films is quite different. In the hydrazine vapor reduction, the nitrogen element is incorporated into the obtained C-rGO film, while no additional element is introduced to the E-rGO film during the electrochemical reduction. Moreover, Raman spectra show that the electrochemical method is more effective than the hydrazine vapor reduction method to reduce the GO films. In addition, E-rGO shows better electrocatalysis towards dopamine than does C-rGO. This study is helpful for researchers to understand these two different reduction methods and choose a suitable one to reduce GO based on their experimental requirements.

  6. Enzyme-free electrochemical immunosensor based on methylene blue and the electro-oxidation of hydrazine on Pt nanoparticles.

    Science.gov (United States)

    Dutta, Gorachand; Nagarajan, Sureshbabu; Lapidus, Lisa J; Lillehoj, Peter B

    2017-06-15

    Enzyme-free electrochemical sensors enable rapid, high sensitivity measurements without the limitations associated with enzyme reporters. However, the performance of non-enzymatic electrochemical sensors tends to suffer from slow electrode kinetics and poor signal stability. We report a new enzyme-free electrochemical immunosensor based on a unique competitive detection scheme using methylene blue (MB), hydrazine and platinum nanoparticles (Pt NPs). This scheme is coupled with a robust immunosandwich format employing a MB-labelled detection antibody as a non-enzymatic reporter. In the presence of the target antigen, surface-immobilized MB consumes interfacial hydrazine thereby diminishing the electro-oxidation of hydrazine on Pt NPs. Thus, the concentration of the antigen is directly proportional to the reduction in the electrochemical signal. For proof-of-concept, this sensor was used to detect Plasmodium falciparum histidine-rich protein 2 (PfHRP2), an important malaria biomarker, in unadulterated human saliva samples. Chronocoulometric measurements showed that this platform exhibits pM-range sensitivity, high specificity and good reproducibility, making it well suited for many biosensing applications including noninvasive diagnostic testing.

  7. Silver nanoparticles sensitized C60(Ag@C60) as efficient electrocatalysts for hydrazine oxidation: Implication for hydrogen generation reaction

    Science.gov (United States)

    Narwade, Shankar S.; Mulik, Balaji B.; Mali, Shivsharan M.; Sathe, Bhaskar R.

    2017-02-01

    Herein, we report the synthesis of silver nanoparticles (Ag NPs; 10 ± 0.5 nm) sensitized Fullerene (C60; 15 ±2 nm) nanocatalysts (Ag@C60) for the first time showing efficient electroatalytic activity for the oxidation of hydrazine demonstrating activity comparable to that of Pt in acidic, neutral and basic media. The performance is comparable with the best available electrocatalytic system and plays a vital role in the overall hydrogen generation reactions from hydrazine as a one of the fuel cell reaction. The materials are synthesized by a simple and scalable synthetic route involving acid functionalization of C60 followed by chemical reduction of Ag+ ions in ethylene glycol at high temperature. The distributation of Silver nanoparticles (Ag NPs) (morphological information) on C60, bonding, its crystal structure, along with activity towards hydrazine oxidation (electrocatalytic) is studied using TEM, XRD, UV-vis, XPS, FTIR and electrochemical (cyclic voltammetry) studies, respectively. The observed efficient electrocatalytic activity of the as-synthesized electrode is attributed to the co-operative response and associated structural defects due to their oxidative functionalization along with thier cooperative functioning at nanodimensions.

  8. Derivatization Ion Chromatography for the Determination of Monoethanolamine in Presence of Hydrazine in PHWR Steam-Water Circuits

    Directory of Open Access Journals (Sweden)

    Ayushi D.

    2011-01-01

    Full Text Available A simple, rapid and accurate method for the determination of monoethanolamine (MEA in PHWR steam-water circuits has been developed. MEA is added in the feed water to provide protection against corrosion while hydrazine is added to scavenge dissolved oxygen. The quantitative determination of MEA in presence of hydrazine was accomplished using derivatization ion chromatography with conductometric detection in nonsuppressed mode. A Metrosep cation 1-2 analytical column and a Metrosep cartridge were used for cation separation. A mixture of 4 mM tartaric acid, 20% acetone and 0.05 mM HNO3 was used as eluent. Acetone in the mobile phase leads to the formation of different derivatives with MEA and hydrazine. The interferences due Na+ and NH4 + were eliminated by adopting a simple pretreatment procedure employing OnGuard-H cartridge. The limit of detection limit of MEA was 0.1 μg mL−1 and the relative standard deviation was 2% for the overall method. The recovery of MEA added was in the range 95%–102%. The method was applied to the determination of MEA in steam generator water samples.

  9. Determining resolvability of mantle plumes with synthetic seismic modeling

    Science.gov (United States)

    Maguire, R.; Van Keken, P. E.; Ritsema, J.; Fichtner, A.; Goes, S. D. B.

    2014-12-01

    Hotspot volcanism in locations such as Hawaii and Iceland is commonly thought to be associated with plumes rising from the deep mantle. In theory these dynamic upwellings should be visible in seismic data due to their reduced seismic velocity and their effect on mantle transition zone thickness. Numerous studies have attempted to image plumes [1,2,3], but their deep mantle origin remains unclear. In addition, a debate continues as to whether lower mantle plumes are visible in the form of body wave travel time delays, or whether such delays will be erased due to wavefront healing. Here we combine geodynamic modeling of mantle plumes with synthetic seismic waveform modeling in order to quantitatively determine under what conditions mantle plumes should be seismically visible. We model compressible plumes with phase changes at 410 km and 670 km, and a viscosity reduction in the upper mantle. These plumes thin from greater than 600 km in diameter in the lower mantle, to 200 - 400 km in the upper mantle. Plume excess potential temperature is 375 K, which maps to seismic velocity reductions of 4 - 12 % in the upper mantle, and 2 - 4 % in the lower mantle. Previous work that was limited to an axisymmetric spherical geometry suggested that these plumes would not be visible in the lower mantle [4]. Here we extend this approach to full 3D spherical wave propagation modeling. Initial results using a simplified cylindrical plume conduit suggest that mantle plumes with a diameter of 1000 km or greater will retain a deep mantle seismic signature. References[1] Wolfe, Cecily J., et al. "Seismic structure of the Iceland mantle plume." Nature 385.6613 (1997): 245-247. [2] Montelli, Raffaella, et al. "Finite-frequency tomography reveals a variety of plumes in the mantle." Science 303.5656 (2004): 338-343. [3] Schmandt, Brandon, et al. "Hot mantle upwelling across the 660 beneath Yellowstone." Earth and Planetary Science Letters 331 (2012): 224-236. [4] Hwang, Yong Keun, et al

  10. Turbulence statistics in a negatively buoyant particle plume - laboratory measurement

    Science.gov (United States)

    Bordoloi, Ankur; Clark, Laura; Veliz, Gerardo; Heath, Michael; Variano, Evan

    2016-11-01

    Negatively buoyant plumes of nylon particles are investigated in quiescent salt-water solution using flow visualization and stereoscopic PIV. Particles of the size 2 mm are continuously released through a nozzle from the top inside a water tank using a screw-conveyor based release mechanism. The plume propagates downward due to gravity, and by virtue of interacting particle wakes, becomes turbulent. The two phases are refractive index matched, so that the velocity field in the interstitial fluid can be quantified using PIV. We examine the velocity fields in the fluid phase to characterize turbulence statistics, such as turbulent kinetic energy, Reynolds stresses in the fully developed region of the plume. Further, we develop an image processing method to obtain particle distribution and particle slip inside the plume. In the presentation, we will discuss these results in the light of existing literature for rising plumes of bubbles under similar experimental conditions.

  11. Characterization of redox conditions in groundwater contaminant plumes

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Bjerg, Poul Løgstrup; Banwarth, Steven A.

    2000-01-01

    Evaluation of redox conditions in groundwater pollution plumes is often a prerequisite for understanding the behaviour of the pollutants in the plume and for selecting remediation approaches. Measuring of redox conditions in pollution plumes is, however, a fairly recent issue and yet relative few...... dubious, if not erroneous. Several other approaches have been used in addressing redox conditions in pollution plumes: redox-sensitive compounds in groundwater samples, hydrogen concentrations in groundwater, concentrations of volatile fatty acids in groundwater, sediment characteristics and microbial...... cases have been reported. No standardised or generally accepted approach exists. Slow electrode kinetics and the common lack of internal equilibrium of redox processes in pollution plumes make, with a few exceptions, direct electrochemical measurement and rigorous interpretation of redox potentials...

  12. A Transonic and Surpersonic Investigation of Jet Exhaust Plume Effects on the Afterbody and Base Pressures of a Body of Revolution

    Science.gov (United States)

    Andrews, C. D.; Cooper, C. E., Jr.

    1974-01-01

    An experimental aerodynamic investigation was conducted to provide data for studies to determine the criteria for simulating rocket engine plume induced aerodynamic effects in the wind tunnel using a simulated gaseous plume. Model surface and base pressure data were obtained in the presence of both a simulated and a prototype gaseous plume for a matrix of plume properties to enable investigators to determine the parameters that correlate the simulated and prototype plume-induced data. The test program was conducted in the Marshall Space Flight Center's 14 x 14-inch trisonic wind tunnel using two models, the first being a strut mounted cone-ogive-cylinder model with a fineness ratio of 9. Model exterior pressures, model plenum chamber and nozzle performance data were obtained at Mach numbers of 0.9, 1.2, 1.46, and 3.48. The exhaust plume was generated by using air as the simulant gas, or Freon-14 (CF4) as the prototype gas, over a chamber pressure range from 0 to 2,000 psia and a total temperature range from 50 to 600 F.

  13. Assessment of analytical and experimental techniques utilized in conducting plume technology tests 575 and 593. [exhaust flow simulation (wind tunnel tests) of scale model Space Shuttle Orbiter

    Science.gov (United States)

    Baker, L. R.; Sulyma, P. R.; Tevepaugh, J. A.; Penny, M. M.

    1976-01-01

    Since exhaust plumes affect vehicle base environment (pressure and heat loads) and the orbiter vehicle aerodynamic control surface effectiveness, an intensive program involving detailed analytical and experimental investigations of the exhaust plume/vehicle interaction was undertaken as a pertinent part of the overall space shuttle development program. The program, called the Plume Technology program, has as its objective the determination of the criteria for simulating rocket engine (in particular, space shuttle propulsion system) plume-induced aerodynamic effects in a wind tunnel environment. The comprehensive experimental program was conducted using test facilities at NASA's Marshall Space Flight Center and Ames Research Center. A post-test examination of some of the experimental results obtained from NASA-MSFC's 14 x 14-inch trisonic wind tunnel is presented. A description is given of the test facility, simulant gas supply system, nozzle hardware, test procedure and test matrix. Analysis of exhaust plume flow fields and comparison of analytical and experimental exhaust plume data are presented.

  14. West Antarctic Mantle Plume Hypothesis and Basal Water Generation

    Science.gov (United States)

    Ivins, Erik; Seroussi, Helene; Wiens, Doug; Bondzio, Johannes

    2017-04-01

    The hypothesis of a deep mantle plume that manifests Pliocene and Quaternary volcanism and present-day seismicity in West Antarctica has been speculated for more than 30 years. Recent seismic images support the plume hypothesis as the cause of Marie Byrd Land (MBL) volcanism and geophysical structure [ Lloyd et al., 2015; Ramirez et al., 2016]. Mantle plumes can more that double the geothermal heat flux, qGHF, above nominal continental values at their axial peak position and raise qGHF in the surrounding plume head to 60 mW/m2 or higher. Unfortunately, there is a dearth of in-situ basal ice sheet data that sample the heat flux. Consequently, we examine a realistic distribution of heat flux associated with a late-Cenozoic mantle plume in West Antarctica and explore its impact on thermal and melt conditions near the ice sheet base. The solid Earth model assumes a parameterized deep mantle plume and head. The 3-D ice flow model includes an enthalpy framework and full-Stokes stress balance. Both the putative plume location and extent are uncertain. Therefore, we perform broadly scoped experiments to characterize plume related basal conditions. The experiments show that mantle plumes have an important local impact on the ice sheet, with basal melting rates reaching several centimeters per year directly above the hotspot. The downstream active lake system of Whillans Ice Stream suggests a rift-related source of anomalous mantle heat. However, the lack of lake and stream activity in MBL suggests a relatively weak plume: one that delivers less flux by 35% below the heat flux to the crustal surface at the site of the Yellowstone hotspot [e.g., DeNosaquo et al., 2009], with peak value no higher than about 145 mW/m2.

  15. Aerosol size distribution in a coagulating plume: Analytical behavior and modeling applications

    Science.gov (United States)

    Turco, Richard P.; Yu, Fangqun

    In a previous paper (Turco and Yu, 1997), a series of analytical solutions were derived for the problem of aerosol coagulation in an expanding plume, as from a jet engine. Those solutions were shown to depend on a single dimensionless time-dependent number, NT, which is related to the particle coagulation kernel and the plume volume. Here, we derive a new analytical expression that describes the particle size distribution in an expanding plume in terms of NT. We show how this solution can be extended to include the effects of soot particles on the evolving volatile sulfuric acid aerosols in an aircraft wake. Our solutions apply primarily to cases where changes in the size distribution—beyond an initial period encompassing emission and prompt nucleation/condensation—is controlled mainly by coagulation. The analytical size distributions allow most of the important properties of an evolving aerosol population—mean size, number greater than a minimum size, surface area density, size dependent reactivities, and optical properties—to be estimated objectively. We have applied our analytical solution to evaluate errors associated with numerical diffusion in a detailed microphysical code, and demonstrate that, if care is not exercised in solving the coagulation equation, substantial errors can result in the predictions at large particle sizes. This effect is particularly important when comparisons between models and field observations are carried out. The analytical expressions derived here can also be employed to initialize models that do not resolve individual aircraft plumes, by providing a simple means for parameterizing the initial aerosol properties after an appropriate mixing time.

  16. Thermal chemistry of hydrazine on clean and oxygen- and water-predosed Cu(110) single-crystal surfaces

    Science.gov (United States)

    Yao, Yunxi; Zaera, Francisco

    2016-08-01

    The chemistry of hydrazine on Cu(110) single-crystal surfaces was probed under ultrahigh vacuum (UHV) conditions by temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). Survey TPD experiments identified molecular nitrogen and ammonia as the main desorbing products from thermal activation of the adsorbate, but small amounts of diazene and NH2· radicals were also detected. At saturation coverage, N2 production leads NH3 desorption by approximately 10 K (with TPD peaks at 350 K versus 360 K, respectively), indicating a preference for dehydrogenation over N-N bond scission steps, and additional nitrogen was seen at even lower temperatures (320 K) in experiments starting with even higher doses of hydrazine. On the other hand, the formation of NH3 and NH2·, which desorb in a wide range of temperatures between approximately 300 K and 700 K, dominates in experiments with low N2H4 doses, presumably because a stronger interaction of the N-N bond with the metal in the flat adsorption geometry expected at such low coverages. Dosing at room temperature seems to also facilitate the dissociative adsorption, albeit via dehydrogenation steps that lead to the subsequent production of more significant amounts of diazene and of molecular hydrogen (in addition to N2, NH3, and NH2·). Preadsorption of oxygen on the Cu(110) surface helps stabilize the hydrazine, increasing its desorption temperature and helping with the low-temperature (320 K) production of N2. Coadsorption of hydrazine with water leads to facile proton exchange, as indicated by the production of NH2D in TPD experiments with N2H4 + D2O. This isotope scrambling must occur at cryogenic temperatures because all water desorbs from the surface below 200 K and no other changes in surface chemistry are observed after that. The implications of all this chemistry to practical applications that may use hydrazine in surface reactions with copper, including its use as a reducing agent in atomic layer

  17. Identification of discontinuities in plasma plume evolution

    CERN Document Server

    Gojani, Ardian B; Obayashi, Shigeru

    2013-01-01

    The ejection of material during laser ablation gives rise to the development of discontinuities in the ambient gas. Several of these discontinuities are observed and characterized, including externally and internally propagating shock waves, contact surface, and the ionization front. Qualitative experimental observations and analysis of these discontinuities is presented. Results from shadowgraphy enabled determination of an irradiance threshold between two different ablation mechanisms, and determination of several stages of plasma plume evolution. Consideration of the refractive index as a dynamic sum of the contributions from gas and electrons led to separate identification of ionization front from the contact surface. Furthermore, ionization front was observed to lead the shock wave at the earlier stage of the ablation.

  18. Modeling contaminant plumes in fractured limestone aquifers

    DEFF Research Database (Denmark)

    Mosthaf, Klaus; Brauns, Bentje; Fjordbøge, Annika Sidelmann

    the established approaches of the equivalent porous medium, discrete fracture and dual continuum models. However, these modeling concepts are not well tested for contaminant plume migration in limestone geologies. Our goal was to develop and evaluate approaches for modeling the transport of dissolved contaminant...... in the planning of field tests and to update the conceptual model in an iterative process. Field data includes information on spill history, distribution of the contaminant (multilevel sampling), geology and hydrogeology. To describe the geology and fracture system, data from borehole logs, packer tests, optical...... distribution in the aquifer. Different models were used for the planning and interpretation of the pump and tracer test. The models were evaluated by examining their ability to describe collected field data. The comparison with data showed that the models have substantially different representations...

  19. Detecting Volcanic Ash Plumes with GNSS Signals

    Science.gov (United States)

    Rainville, N.; Larson, K. M.; Palo, S. E.; Mattia, M.; Rossi, M.; Coltelli, M.; Roesler, C.; Fee, D.

    2016-12-01

    Global Navigation Satellite Systems (GNSS) receivers are commonly placed near volcanic sites to measure ground deformation. In addition to the carrier phase data used to measure ground position, these receivers also record Signal to Noise ratio (SNR) data. Larson (2013) showed that attenuations in SNR data strongly correlate with ash emissions at a series of eruptions of Redoubt Volcano. This finding has been confirmed at eruptions for Tongariro, Mt Etna, Mt Shindake, and Sakurajima. In each of these detections, very expensive geodetic quality GNSS receivers were used. If low-cost GNSS instruments could be used instead, a networked array could be deployed and optimized for plume detection and tomography. The outputs of this sensor array could then be used by both local volcanic observatories and Volcano Ash Advisory Centers. Here we will describe progress in developing such an array. The sensors we are working with are intended for navigation use, and thus lack the supporting power and communications equipment necessary for a networked system. Reliably providing those features is major challenge for the overall sensor design. We have built prototypes of our Volcano Ash Plume Receiver (VAPR), with solar panels, lithium-ion batteries and onboard data storage for preliminary testing. We will present results of our field tests of both receivers and antennas. A second critical need for our array is a reliable detection algorithm. We have tested our algorithm on data from recent eruptions and have incorporated the noise characteristics of the low-cost GNSS receiver. We have also developed a simulation capability so that the receivers can be deployed to optimize vent crossing GNSS signals.

  20. Effects of hydrazine derivatives on vascular smooth muscle contractility, blood pressure and cGMP production in rats: comparison with hydralazine.

    Science.gov (United States)

    Vidrio, Horacio; Fernández, Gabriela; Medina, Martha; Alvarez, Ezequiel; Orallo, Francisco

    2003-01-01

    Hydralazine is a hydrazine derivative used clinically as a vasodilator and antihypertensive agent. Despite numerous studies with the drug, its mechanism of action has remained unknown; guanylate cyclase activation and release of endothelial relaxing factors are thought to be involved in its vasodilator effect. Other hydrazine derivatives are known to stimulate guanylate cyclase and could therefore share the vasodilator activity of hydralazine, although such possibility has not been assessed systematically. In the present study, hydralazine, hydrazine, phenylhydrazine, and isoniazid were evaluated for vascular smooth muscle relaxation in rat aortic rings with and without endothelium, as well as after incubation with the guanylate cyclase inhibitor methylene blue. They were also tested for enhancement of cyclic guanosine monophosphate (cGMP) production by cultured rat aortic smooth muscle cells and for hypotension in the anesthetized rat. All hydrazines relaxed aortic rings, an action unaffected by endothelium removal and, in all cases except hydralazine, antagonized by methylene blue. Only phenylhydrazine increased cGMP production and only hydralazine markedly lowered blood pressure. It was concluded that hydralazine vascular relaxation is independent of endothelium and is not related to guanylate cyclase activation. The other hydrazines studied also elicit endothelium-independent relaxation, but the effect is related to guanylate cyclase. The marked hypotensive effect of hydralazine contrasts with its modest relaxant activity and is not shared by the other hydrazines. The fact that hydrazine and isoniazid produce methylene blue-sensitive relaxation, yet do not enhance cGMP production suggests the need for activating factors present in aortic rings but not in isolated cells.

  1. Learning to Rapidly Re-Contact the Lost Plume in Chemical Plume Tracing

    Directory of Open Access Journals (Sweden)

    Meng-Li Cao

    2015-03-01

    Full Text Available Maintaining contact between the robot and plume is significant in chemical plume tracing (CPT. In the time immediately following the loss of chemical detection during the process of CPT, Track-Out activities bias the robot heading relative to the upwind direction, expecting to rapidly re-contact the plume. To determine the bias angle used in the Track-Out activity, we propose an online instance-based reinforcement learning method, namely virtual trail following (VTF. In VTF, action-value is generalized from recently stored instances of successful Track-Out activities. We also propose a collaborative VTF (cVTF method, in which multiple robots store their own instances, and learn from the stored instances, in the same database. The proposed VTF and cVTF methods are compared with biased upwind surge (BUS method, in which all Track-Out activities utilize an offline optimized universal bias angle, in an indoor environment with three different airflow fields. With respect to our experimental conditions, VTF and cVTF show stronger adaptability to different airflow environments than BUS, and furthermore, cVTF yields higher success rates and time-efficiencies than VTF.

  2. Prototype development and test results of a continuous ambient air monitoring system for hydrazine at the 10 ppb level

    Science.gov (United States)

    Meneghelli, Barry; Parrish, Clyde; Barile, Ron; Lueck, Dale E.

    1995-01-01

    A Hydrazine Vapor Area Monitor (HVAM) system is currently being field tested as a detector for the presence of hydrazine in ambient air. The MDA/Polymetron Hydrazine Analyzer has been incorporated within the HVAM system as the core detector. This analyzer is a three-electrode liquid analyzer typically used in boiler feed water applications. The HVAM system incorporates a dual-phase sample collection/transport method which simultaneously pulls ambient air samples containing hydrazine and a very dilute sulfuric acid solution (0.0001 M) down a length of 1/4 inch outside diameter (OD) tubing from a remote site to the analyzer. The hydrazine-laden dilute acid stream is separated from the air and the pH is adjusted by addition of a dilute caustic solution to a pH greater than 10.2 prior to analysis. Both the dilute acid and caustic used by the HVAM are continuously generated during system operation on an "as needed" basis by mixing a metered amount of concentrated acid/base with dilution water. All of the waste water generated by the analyzer is purified for reuse by Barnstead ion-exchange cartridges so that the entire system minimizes the generation of waste materials. The pumping of all liquid streams and mixing of the caustic solution and dilution water with the incoming sample are done by a single pump motor fitted with the appropriate mix of peristaltic pump heads. The signal to noise (S/N) ratio of the analyzer has been enhanced by adding a stirrer in the MDA liquid cell to provide mixing normally generated by the high liquid flow rate designed by the manufacturer. An onboard microprocessor continuously monitors liquid levels, sample vacuum, and liquid leak sensors, as well as handles communications and other system functions (such as shut down should system malfunctions or errors occur). The overall system response of the HVAM can be automatically checked at regular intervals by measuring the analyzer response to a metered amount of calibration standard injected

  3. Conformational effects on hydrazine and OH coadsorption on Ni(111): A first-principles investigation

    Science.gov (United States)

    Agusta, Mohammad Kemal; Purwoko, Prasetiyo Hadi; Saputro, Adhitya Gandaryus; Fathurrahman, Fadjar; Dipojono, Hermawan K.; Diño, Wilson Agerico

    2017-10-01

    Using first-principles Density Functional Theory calculations, we investigated coadsorption of hydrazine (N2H4) and OH on Ni(111) surface. Two types of N2H4 conformations: anti and cis-conformer, with coadsorbed OH on several high symmetry sites on Ni(111) surface were studied. We found that coadsorption with cis-conformer N2H4 significantly modifies OH site preferences while such modification is less profound for coadsorption with anti-conformer N2H4. On the other way around, the cis-confomer N2H4 coadsorption becomes more stable due to the pressence of OH. We identified the electrostatic attractive dipole interaction between the coadsorbed species as the underlying mechanism for the stabilization. This electrostatic interaction is particularly strong for cis-conformer N2H4 due to its large dipole moment. We also found Nsbnd H bond elongation for cis-conformer N2H4 coadsorption with OH due to the interaction between accumulated charge in OH with the H atom of N2H4. Therefore, it can be inferred that coadsorption with OH promotes the dehydrogenation reaction of N2H4 via stabilization of cis-confomer N2H4.

  4. Hydrogen generation from decomposition of hydrous hydrazine over Ni-Ir/CeO2 catalyst

    Directory of Open Access Journals (Sweden)

    Hongbin Dai

    2017-02-01

    Full Text Available The synthesis of highly active and selective catalysts is the central issue in the development of hydrous hydrazine (N2H4·H2O as a viable hydrogen carrier. Herein, we report the synthesis of bimetallic Ni-Ir nanocatalyts supported on CeO2 using a one-pot coprecipitation method. A combination of XRD, HRTEM and XPS analyses indicate that the Ni-Ir/CeO2 catalyst is composed of tiny Ni-Ir alloy nanoparticles with an average size of around 4 nm and crystalline CeO2 matrix. The Ni-Ir/CeO2 catalyst exhibits high catalytic activity and excellent selectivity towards hydrogen generation from N2H4·H2O at mild temperatures. Furthermore, in contrast to previously reported Ni-Pt catalysts, the Ni-Ir/CeO2 catalyst shows an alleviated requirement on alkali promoter to achieve its optimal catalytic performance.

  5. Investigation of a catalytic gas generator for the Space Shuttle APU. [hydrazine Auxiliary Propulsion Unit

    Science.gov (United States)

    Emmons, D. L.; Huxtable, D. D.; Blevins, D. R.

    1974-01-01

    An investigation was conducted to establish the capability of a monopropellant hydrazine catalytic gas generator to meet the requirements specified for the Space Shuttle APU. Detailed analytical and experimental studies were conducted on potential problem areas including long-term nitriding effects on materials, design variables affecting catalyst life, vehicle vibration effects, and catalyst oxidation/contamination. A full-scale gas generator, designed to operate at a chamber pressure of 750 psia and a flow rate of 0.36 lbm/sec, was fabricated and subjected to three separate life test series. The objective of the first test series was to demonstrate the capability of the gas generator to successfully complete 20 simulated Space Shuttle missions in steady-state operation. The gas generator was then refurbished and subjected to a second series of tests to demonstrate the pulse-mode capability of the gas generator during 20 simulated missions. The third series of tests was conducted with a refurbished reactor to further demonstrate pulse-mode capability with a modified catalyst bed.

  6. Influence of ultrasonic waves in the reduction of nitrate to nitrite by hydrazine-Cu(II).

    Science.gov (United States)

    Silva, Luciana A; Korn, Mauro; de Andrade, Jailson B

    2007-02-01

    Colorimetric methods are still important for determining nitrate and nitrite. A critical step in the use of these methods to determine nitrate in low concentrations is the reaction time required to totally reduce nitrate to nitrite, i.e., 24h in the dark. This work involved a study of the influence of ultrasonic irradiation on the nitrate reduction reaction by hydrazine. Our findings indicated that ultrasonic irradiation, associated with copper(II) ion as a catalyst, increased the redox reaction rate, decreasing the reaction time to about 10min when the power of the ultrasonic irradiation was set in 14.0357W. The strong influence of the ultrasonic irradiation in the reduction reaction rates can be sustained by an excellent linear correlation (R(2)=0.9993) between the kinetic constants and ultrasonic powers. Nitrate conversion also increased from 68% to 98% at the latter conditions. It thus become clear that high intensity ultrasound is very beneficial for this reduction reaction to proceed in good yield and in short reaction time in comparison to its silent reaction.

  7. Effects of hydrazine addition on gas evolution and performance of the direct borohydride fuel cell

    Science.gov (United States)

    Qin, H. Y.; Liu, Z. X.; Yin, W. X.; Zhu, J. K.; Li, Z. P.

    A fuel cell configuration using alkaline NaBH 4-N 2H 4 solutions as the fuel is suggested. Gas evolution behaviors and cell performances of alkaline NaBH 4-N 2H 4 solutions on different catalysts have been studied. It is found that gas evolution behaviors are influenced by the applied anodic catalysts and the concentration of NaBH 4 and N 2H 4. NaBH 4 is mainly electro-oxidized on Pd but N 2H 4 is mainly electro-oxidized on Ni and surface-treated Zr-Ni alloy when using NaBH 4-N 2H 4 solutions as the fuel and a composite of Pd, Ni and surface-treated Zr-Ni alloy as the anodic catalyst. The cyclic voltammetry results show that electrochemical oxidation potential of NaBH 4 is higher than that of N 2H 4. Adding hydrazine into alkaline sodium borohydride solutions can suppress gas evolution and improve the cell performance of the DBFC. The performances of fuel cells using NaBH 4-N 2H 4 solutions are comparable to that of fuel cell using N 2H 4 solution.

  8. NW Iberia Shelf Dynamics. Study of the Douro River Plume.

    Directory of Open Access Journals (Sweden)

    Isabel Iglesias

    2014-06-01

    Full Text Available River plumes are one of the most important mechanisms that transport the terrestrial materials to the coast and the ocean. Some examples of those materials are pollutants, essential nutrients, which enhance the phytoplankton productivity or sediments, which settle on the seabed producing modifications on the bathymetry affecting the navigation channels. The mixing between the riverine and the oceanic waters can induce instabilities, which might generate bulges, filaments, and buoyant currents over the continental shelf. Offshore, the buoyant riverine water could form a front with the oceanic waters often related with the occurrence of current-jets, eddies and strong mixing. The study and modelling of the river plumes is a key factor for the complete understanding of sediment transport mechanisms and patterns, and of coastal physics and dynamic processes. On this study the Douro River plume will be simulated. The Douro River is located on the north-west Iberian coast and its daily averaged freshwater discharge can range values from 0 to 13000 m3/s. This variability impacts the formation of the river plumes and its dispersion along the continental shelf. This study builds on the long-term objective of generate a Douro River plume forecasting system as part of the RAIA and RAIA.co projects. Satellite imagery was analyzed showing that the river Douro is one of the main sources of suspended particles, dissolved material and chlorophyll in the NW Iberian Shelf. The Regional Oceanic Modeling System (ROMS model was selected to reproduce scenarios of plume generation, retention and dispersion. Whit this model, three types of simulations were performed: (i schematic winds simulations with prescribed river flow, wind speed and direction; (ii multi-year climatological simulation, with river flow and temperature change for each month; (iii extreme case simulation, based on the Entre-os-Rios accident situation. The schematic wind case-studies suggest that the

  9. Natural versus forced convection in laminar starting plumes

    CERN Document Server

    Rogers, Michael C

    2009-01-01

    A starting plume or jet has a well-defined, evolving head that is driven through the surrounding quiescent fluid by a localized flux of either buoyancy or momentum, or both. We studied the scaling and morphology of starting plumes produced by a constant flux of buoyant fluid from a small, submerged outlet. The plumes were laminar and spanned a wide range of plume Richardson numbers Ri. Ri is the dimensionless ratio of the buoyancy forces to inertial effects, and is thus our measurements crossed over the transition between buoyancy-driven plumes and momentum-driven jets. We found that the ascent velocity of the plume, nondimensionalized by Ri, exhibits a power law relationship with Re, the Reynolds number of the injected fluid in the outlet pipe. We also found that as the threshold between buoyancy-driven and momentum-driven flow was crossed, two distinct types of plume head mophologies existed: confined heads, produced in the Ri > 1 regime, and dispersed heads, which are found in the Ri < 1 regime. Head di...

  10. Biogeochemistry and isotope geochemistry of a landfill leachate plume.

    Science.gov (United States)

    van Breukelen, Boris M; Röling, Wilfred F M; Groen, Jacobus; Griffioen, Jasper; van Verseveld, Henk W

    2003-09-01

    The biogeochemical processes were identified which improved the leachate composition in the flow direction of a landfill leachate plume (Banisveld, The Netherlands). Groundwater observation wells were placed at specific locations after delineating the leachate plume using geophysical tests to map subsurface conductivity. Redox processes were determined using the distribution of solid and soluble redox species, hydrogen concentrations, concentration of dissolved gases (N(2), Ar, and CH(4)), and stable isotopes (delta15N-NO(3), delta34S-SO(4), delta13C-CH(4), delta2H-CH(4), and delta13C of dissolved organic and inorganic carbon (DOC and DIC, respectively)). The combined application of these techniques improved the redox interpretation considerably. Dissolved organic carbon (DOC) decreased downstream in association with increasing delta13C-DOC values confirming the occurrence of degradation. Degradation of DOC was coupled to iron reduction inside the plume, while denitrification could be an important redox process at the top fringe of the plume. Stable carbon and hydrogen isotope signatures of methane indicated that methane was formed inside the landfill and not in the plume. Total gas pressure exceeded hydrostatic pressure in the plume, and methane seems subject to degassing. Quantitative proof for DOC degradation under iron-reducing conditions could only be obtained if the geochemical processes cation exchange and precipitation of carbonate minerals (siderite and calcite) were considered and incorporated in an inverse geochemical model of the plume. Simulation of delta13C-DIC confirmed that precipitation of carbonate minerals happened.

  11. Monitoring radioactive plumes by airborne gamma-ray spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Grasty, R.L. [Exploranium, Mississauga, Ontario (Canada); Hovgaard, J. [Danish Emergency Management Agency, Birkerod (Germany); Multala, J. [Geological Survey of Finland, Espoo (Finland)

    1996-06-01

    Airborne gamma-ray spectrometer surveys using large volume sodium-iodide detectors are routinely flown throughout the world for mineral exploration and geological mapping. Techniques have now been developed to detect and map man-made sources of radiation. In Canada, airborne gamma-rays surveys have been flown around nuclear reactors to map {sup 41}Ar plumes from nuclear reactors and to calculate the dose rate at ground level. In May 1986, the Finnish Geological survey aircraft flew through a radioactive plume from the Chernobyl nuclear accident. As the aircraft flew through the plume, the aircraft became increasingly contaminated. By measuring the final aircraft contamination, the activity of the plume could be separated from the contamination due to the aircraft. Within 1 h of encountering the plume, the aircraft activity was comparable to the maximum levels found in the plume. From an analysis of the gamma-ray spectra, the concentration of {sup 131}I and {sup 140}La within the plume were calculated as a function of time.

  12. Cooling tower and plume modeling for satellite remote sensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Powers, B.J.

    1995-05-01

    It is often useful in nonproliferation studies to be able to remotely estimate the power generated by a power plant. Such information is indirectly available through an examination of the power dissipated by the plant. Power dissipation is generally accomplished either by transferring the excess heat generated into the atmosphere or into bodies of water. It is the former method with which we are exclusively concerned in this report. We discuss in this report the difficulties associated with such a task. In particular, we primarily address the remote detection of the temperature associated with the condensed water plume emitted from the cooling tower. We find that the effective emissivity of the plume is of fundamental importance for this task. Having examined the dependence of the plume emissivity in several IR bands and with varying liquid water content and droplet size distributions, we conclude that the plume emissivity, and consequently the plume brightness temperature, is dependent upon not only the liquid water content and band, but also upon the droplet size distribution. Finally, we discuss models dependent upon a detailed point-by-point description of the hydrodynamics and thermodynamics of the plume dynamics and those based upon spatially integrated models. We describe in detail a new integral model, the LANL Plume Model, which accounts for the evolution of the droplet size distribution. Some typical results obtained from this model are discussed.

  13. 3-D numerical modeling of plume-induced subduction initiation

    Science.gov (United States)

    Baes, Marzieh; Gerya, taras; Sobolev, Stephan

    2016-04-01

    Investigation of mechanisms involved in formation of a new subduction zone can help us to better understand plate tectonics. Despite numerous previous studies, it is still unclear how and where an old oceanic plate starts to subduct beneath the other plate. One of the proposed scenarios for nucleation of subduction is plume-induced subduction initiation, which was investigated in detail, using 2-D models, by Ueda et al. (2008). Recently. Gerya et al. (2015), using 3D numerical models, proposed that plume-lithosphere interaction in the Archean led to the subduction initiation and onset of plate tectonic. In this study, we aim to pursue work of Ueda et al. (2008) by incorporation of 3-D thermo-mechanical models to investigate conditions leading to oceanic subduction initiation as a result of thermal-chemical mantle plume-lithosphere interaction in the modern earth. Results of our experiments show four different deformation regimes in response to plume-lithosphere interaction, that are a) self-sustaining subduction initiation where subduction becomes self-sustained, b) freezing subduction initiation where subduction stops at shallow depths, c) slab break-off where subducting circular slab breaks off soon after formation and d) plume underplating where plume does not pass through the lithosphere but spreads beneath it (failed subduction initiation). These different regimes depend on several parameters such as plume's size, composition and temperature, lithospheric brittle/plastic strength, age of the oceanic lithosphere and presence/absence of lithospheric heterogeneities. Results show that subduction initiates and becomes self-sustained when lithosphere is older than 10 Myr and non-dimensional ratio of the plume buoyancy force and lithospheric strength above the plume is higher than 2.

  14. Effects of rocket engines on laser during lunar landing

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Xiong, E-mail: wanxiong1@126.com [Key Laboratory of Space Active Opto-Electronics Technology, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai 200083 (China); Key Laboratory of Nondestructive Test (Ministry of Education), Nanchang Hangkong University, Nanchang 330063 (China); Shu, Rong; Huang, Genghua [Key Laboratory of Space Active Opto-Electronics Technology, Shanghai Institute of Technical Physics, Chinese Academy of Science, Shanghai 200083 (China)

    2013-11-15

    In the Chinese moon exploration project “ChangE-3”, the laser telemeter and lidar are important equipments on the lunar landing vehicle. A low-thrust vernier rocket engine works during the soft landing, whose plume may influence on the laser equipments. An experiment has first been accomplished to evaluate the influence of the plume on the propagation characteristics of infrared laser under the vacuum condition. Combination with our theoretical analysis has given an appropriate assessment of the plume's effects on the infrared laser hence providing a valuable basis for the design of lunar landing systems.

  15. Modelling exhaust plume mixing in the near field of an aircraft

    Directory of Open Access Journals (Sweden)

    F. Garnier

    Full Text Available A simplified approach has been applied to analyse the mixing and entrainment processes of the engine exhaust through their interaction with the vortex wake of an aircraft. Our investigation is focused on the near field, extending from the exit nozzle until about 30 s after the wake is generated, in the vortex phase. This study was performed by using an integral model and a numerical simulation for two large civil aircraft: a two-engine Airbus 330 and a four-engine Boeing 747. The influence of the wing-tip vortices on the dilution ratio (defined as a tracer concentration shown. The mixing process is also affected by the buoyancy effect, but only after the jet regime, when the trapping in the vortex core has occurred. In the early wake, the engine jet location (i.e. inboard or outboard engine jet has an important influence on the mixing rate. The plume streamlines inside the vortices are subject to distortion and stretching, and the role of the descent of the vortices on the maximum tracer concentration is discussed. Qualitative comparison with contrail photograph shows similar features. Finally, tracer concentration of inboard engine centreline of B-747 are compared with other theoretical analyses and measured data.

  16. Multiphase CFD modeling of nearfield fate of sediment plumes

    DEFF Research Database (Denmark)

    Saremi, Sina; Hjelmager Jensen, Jacob

    2014-01-01

    Disposal of dredged material and the overflow discharge during the dredging activities is a matter of concern due to the potential risks imposed by the plumes on surrounding marine environment. This gives rise to accurately prediction of the fate of the sediment plumes released in ambient waters....... The two-phase mixture solution based on the drift-flux method is evaluated for 3D simulation of material disposal and overflow discharge from the hoppers. The model takes into account the hindrance and resistance mechanisms in the mixture and is capable of describing the flow details within the plumes...... and gives excellent results when compared to experimental data....

  17. Airborne Gamma-ray Measurements in the Chernobyl Plume

    DEFF Research Database (Denmark)

    Grasty, R. L.; Hovgaard, Jens; Multala, J.

    1997-01-01

    On 29 April 1986, the Geological Survey of Finland (GSF) survey aircraft with a gamma ray spectrometer flew through a radioactive plume from the Chernobyl nuclear accident. The aircraft became contaminated and the gamma spectrometer measured radioactivity in the plume as well as radioactivity...... on the aircraft. By using simple assumptions on the build-up of contamination it has been possible to separate the signals from contamination and from plume. The analysis further showed that even a detector/spectrometer with low energy resolution is able to identify a contamination with iodine....

  18. Laboratory Study of Dispersion of Buoyant Surface Plumes

    DEFF Research Database (Denmark)

    Petersen, Ole; Larsen, Torben

    1990-01-01

    A laboratory a study on surface dispersion of buoyant plumes in open channel turbulence in made, where the buoyancy is due to both salinity and heat. The measured parameters are the downstream derivative of a plume width and height, which are integral-characteristics of the distributions of density......-differences. Other methods as infra-red sensing are used for visualizing purpose. The results are used to calibrate an integral model of the dispersion. Conclusions are that the dispersion of a buoyant surface plume can be treated the superposition of a buoyancy induced stretching and turbulent diffusion, reduced...

  19. Lightning in Colorado forest fire smoke plumes during summer 2012

    Science.gov (United States)

    Lang, T. J.; Krehbiel, P. R.; Dolan, B.; Lindsey, D.; Rutledge, S. A.; Rison, W.

    2012-12-01

    May and June 2012 were unusually hot and dry in Colorado, which was suffering from a strong drought. A major consequence of this climatic regime was one of the most destructive forest fire seasons in state history, with hundreds of thousands of acres of forest and grassland consumed by flames, hundreds of homes burned, and several lives lost. Many of these fires occurred within range of the newly installed Colorado Lightning Mapping Array (COLMA), which provides high-resolution observations of discharges over a large portion of the state. The COLMA was installed in advance of the Deep Convective Clouds and Chemistry (DC3) project. High-altitude lightning was observed to occur sporadically in the smoke plumes over three major fires that occurred during early summer: Hewlett Gulch, High Park, and Waldo Canyon. Additionally, the Colorado State University CHILL (CSU-CHILL) and Pawnee radars observed the Hewlett Gulch plume electrify with detailed polarimetric and dual-Doppler measurements, and also provided these same measurements for the High Park plume when it was not producing lightning. Meanwhile, local Next Generation Radars (NEXRADs) provided observations of the electrified High Park and Waldo Canyon plumes. All of these plumes also were observed by geostationary meteorological satellites. These observations provide an unprecedented dataset with which to study smoke plume and pyrocumulus electrification. The polarimetric data - low reflectivity, high differential reflectivity, low correlation coefficient, and noisy differential phase - were consistent with the smoke plumes and associated pyrocumulus being filled primarily with irregularly shaped ash particles. Lightning was not observed in the plumes until they reached over 10 km above mean sea level, which was an uncommon occurrence requiring explosive fire growth combined with increased meteorological instability and reduced wind shear. Plume updraft intensification and echo-top growth led the occurrence of

  20. Rocket Plume Scaling for Orion Wind Tunnel Testing

    Science.gov (United States)

    Brauckmann, Gregory J.; Greathouse, James S.; White, Molly E.

    2011-01-01

    A wind tunnel test program was undertaken to assess the jet interaction effects caused by the various solid rocket motors used on the Orion Launch Abort Vehicle (LAV). These interactions of the external flowfield and the various rocket plumes can cause localized aerodynamic disturbances yielding significant and highly non-linear control amplifications and attenuations. This paper discusses the scaling methodologies used to model the flight plumes in the wind tunnel using cold air as the simulant gas. Comparisons of predicted flight, predicted wind tunnel, and measured wind tunnel forces-and-moments and plume flowfields are made to assess the effectiveness of the selected scaling methodologies.

  1. Non-Toxic Orbital Maneuvering System Engine Development

    Science.gov (United States)

    Green, Christopher; Claflin, Scott; Maeding, Chris; Butas, John

    1999-01-01

    Recent results using the Aestus engine operated with LOx/ethanol propellant are presented. An experimental program at Rocketdyne Propulsion and Power is underway to adapt this engine for the Boeing Reusable Space Systems Division non-toxic Orbital Maneuvering System/Reaction control System (OMS/RCS) system. Daimler-Chrysler Aerospace designed the Aestus as an nitrogen tetroxide/monomethyl hydrazine (NTO/MMH) upper-stage engine for the Ariane 5. The non-toxic OMS/RCS system's preliminary design requires a LOx/ethanol (O2/C2H5OH) engine that operates with a mixture ratio of 1.8, a specific impulse of 323 seconds, and fits within the original OMS design envelope. This paper describes current efforts to meet these requirements including, investigating engine performance using LOx/ethanol, developing the en-ine system sizing package, and meeting the vehicle operation parameters. Data from hot-fire testing are also presented and discussed.

  2. Effects of facility backpressure on the performance and plume of a Hall thruster

    Science.gov (United States)

    Walker, Mitchell Louis Ronald

    2005-07-01

    this work aims to develop a fundamental understanding of how multi-kW clustered Hall thrusters operate and how to use single-engine ground-based data to predict the performance, plume interaction, and operation of a cluster. The results show that the plume and operating characteristics of the cluster are governed primarily by the facility backpressure and not the adjacent thruster. At nearly equal backpressure, the thrust is equal to the sum of the thrust of the monolithic thrusters at the lower anode flow rate. At the upper anode flow rate, the sum of the thrust of the monolithic thrusters under predicts the cluster thrust by 5%. This may be caused by each cluster element ingesting unionized propellant from the adjacent thruster. In addition, a cathode sharing investigation shows negligible change in the discharge current and cathode-to-ground voltage for thruster centerline separation distances up to 2 meters. A cathode displacement investigation shows that the Hall thruster starts reliably and performs nominally at cathode separation distances up to 1.1 meters. Collectively, the results of this work shed light on future facility designs that can reduce facility effects at pumping speeds that are not significantly above those of current facilities.

  3. Simulation of UV atomic radiation for application in exhaust plume spectrometry

    Science.gov (United States)

    Wallace, T. L.; Powers, W. T.; Cooper, A. E.

    1993-06-01

    Quantitative analysis of exhaust plume spectral data has long been a goal of developers of advanced engine health monitoring systems which incorporate optical measurements of rocket exhaust constituents. Discussed herein is the status of present efforts to model and predict atomic radiation spectra and infer free-atom densities from emission/absorption measurements as part of the Optical Plume Anomaly Detection (OPAD) program at Marshall Space Flight Center (MSFC). A brief examination of the mathematical formalism is provided in the context of predicting radiation from the Mach disk region of the SSME exhaust flow at nominal conditions during ground level testing at MSFC. Computational results are provided for Chromium and Copper at selected transitions which indicate a strong dependence upon broadening parameter values determining the absorption-emission line shape. Representative plots of recent spectral data from the Stennis Space Center (SSC) Diagnostic Test Facility (DTF) rocket engine are presented and compared to numerical results from the present self-absorbing model; a comprehensive quantitative analysis will be reported at a later date.

  4. Inexpensive photodiode arrays for use in rocket plume and hot source monitoring and diagnostics

    Science.gov (United States)

    Snider, Dallas; Shanks, Robert; Cole, Reagan; Hudson, M. Keith

    2003-09-01

    The spectroscopic analysis of plume emissions is a non-intrusive method which has been used to check for fatigue and possible damage throughout the pumps and other mechanisms in a rocket motor or engine. These components are made of various alloys. Knowing the composition of the alloys and for which parts they are used, one can potentially determine from the emissions in the plume which component is failing. Currently, optical multichannel analyser systems are being used which utilize charge coupled devices, cost tens of thousands of dollars, are somewhat delicate, and usually require cooling. We have developed two rugged instruments using less expensive linear photodiode arrays as detectors. A high-resolution system was used to detect atomic emission lines while a low-resolution system was used to detect molecular emission bands. We have also written data acquisition software and built electronic circuits to control the arrays and collect data. While the National Aeronautics and Space Administration has used similar systems for characterization of the space shuttle main engine, the emissions from other rocket systems have not been surveyed so well. The two instruments described will be utilized to study hybrid rocket emissions at the University of Arkansas-Little Rock hybrid rocket facility.

  5. Plume Diagnostics for Combustion Stability Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Sierra Engineering and Purdue University propose to leverage combustion stability testing, already funded and planned for the second and third quarters of next year...

  6. Effect of aircraft exhaust sulfur emissions on near field plume aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Brown, R.C.; Miake-Lye, R.C.; Anderson, M.R.; Kolb, C.E. [Aerodyne Research, Inc., Billerica, MA (United States). Center for Chemical and Environmental Physics

    1997-12-31

    Based on estimated exit plane sulfur speciation, a two dimensional, axisymmetric flow field model with coupled gas phase oxidation kinetics and aerosol nucleation and growth dynamics is used to evaluate the effect of fuel sulfur oxidation in the engine on the formation and growth of volatile H{sub 2}SO{sub 4}/H{sub 2}O aerosols in the near field plume. The conversion of fuel sulfur to sulfur trioxide and sulfuric acid in the engine is predicted to significantly increase the number density and surface area density of volatile H{sub 2}SO{sub 4}/H{sub 2}O aerosols and the chemical activation of exhaust soot particulates. This analysis indicates the need for experimental measurements of exhaust SO{sub x} emissions to fully assess the atmospheric impact of aircraft emissions. (author) 18 refs.; Submitted to Geophysical Research Letters

  7. Eastern Dharwar Craton, India: Continental lithosphere growth by accretion of diverse plume and arc terranes

    Directory of Open Access Journals (Sweden)

    C. Manikyamba

    2012-05-01

    Archean lithospheric mantle, distinctive in being thick, refractory, and buoyant, formed complementary to the accreted plume and convergent margin terranes, as migrating arcs captured thick plume-plateaus, and the refractory, low density, residue of plume melting coupled with accreted imbricated plume-arc crust.

  8. Linking Europa's plume activity to tides, tectonics, and liquid water

    CERN Document Server

    Rhoden, Alyssa R; Roth, Lorenz; Retherford, Kurt

    2015-01-01

    Much of the geologic activity preserved on Europa's icy surface has been attributed to tidal deformation, mainly due to Europa's eccentric orbit. Although the surface is geologically young (30 - 80 Myr), there is little information as to whether tidally-driven surface processes are ongoing. However, a recent detection of water vapor near Europa's south pole suggests that it may be geologically active. Initial observations indicated that Europa's plume eruptions are time-variable and may be linked to its tidal cycle. Saturn's moon, Enceladus, which shares many similar traits with Europa, displays tidally-modulated plume eruptions, which bolstered this interpretation. However, additional observations of Europa at the same time in its orbit failed to yield a plume detection, casting doubt on the tidal control hypothesis. The purpose of this study is to analyze the timing of plume eruptions within the context of Europa's tidal cycle to determine whether such a link exists and examine the inferred similarities and...

  9. Saturated Zone Plumes in Volcanic Rock: Implications for Yucca Mountain

    Energy Technology Data Exchange (ETDEWEB)

    S. Kelkar; R. Roback; B. Robinson; G. Srinivasan; C. Jones; P. Reimus

    2006-02-14

    This paper presents a literature survey of the occurrences of radionuclide plumes in saturated, fractured rocks. Three sites, Idaho National laboratory, Hanford, and Oak Ridge are discussed in detail. Results of a modeling study are also presented showing that the length to width ratio of a plume starting within the repository footprint at the Yucca Mountain Project site, decreases from about 20:1 for the base case to about 4:1 for a higher value of transverse dispersivity, indicating enhanced lateral spreading of the plume. Due to the definition of regulatory requirements, this lateral spreading does not directly impact breakthrough curves at the 18 km compliance boundary, however it increases the potential that a plume will encounter reducing conditions, thus significantly retarding the transport of sorbing radionuclides.

  10. Effects of rotation on turbulent buoyant plumes in stratified environments

    National Research Council Canada - National Science Library

    Fabregat Tomàs, Alexandre; Poje, Andrew C; Özgökmen, Tamay M; Dewar, William K

    2016-01-01

    We numerically investigate the effects of rotation on the turbulent dynamics of thermally driven buoyant plumes in stratified environments at the large Rossby numbers characteristic of deep oceanic releases...

  11. False alarm recognition in hyperspectral gas plume identification

    Science.gov (United States)

    Conger, James L [San Ramon, CA; Lawson, Janice K [Tracy, CA; Aimonetti, William D [Livermore, CA

    2011-03-29

    According to one embodiment, a method for analyzing hyperspectral data includes collecting first hyperspectral data of a scene using a hyperspectral imager during a no-gas period and analyzing the first hyperspectral data using one or more gas plume detection logics. The gas plume detection logic is executed using a low detection threshold, and detects each occurrence of an observed hyperspectral signature. The method also includes generating a histogram for all occurrences of each observed hyperspectral signature which is detected using the gas plume detection logic, and determining a probability of false alarm (PFA) for all occurrences of each observed hyperspectral signature based on the histogram. Possibly at some other time, the method includes collecting second hyperspectral data, and analyzing the second hyperspectral data using the one or more gas plume detection logics and the PFA to determine if any gas is present. Other systems and methods are also included.

  12. A Thermal Plume Model for the Martian Convective Boundary Layer

    CERN Document Server

    Colaïtis, Arnaud; Hourdin, Frédéric; Rio, Catherine; Forget, François; Millour, Ehouarn

    2013-01-01

    The Martian Planetary Boundary Layer [PBL] is a crucial component of the Martian climate system. Global Climate Models [GCMs] and Mesoscale Models [MMs] lack the resolution to predict PBL mixing which is therefore parameterized. Here we propose to adapt the "thermal plume" model, recently developed for Earth climate modeling, to Martian GCMs, MMs, and single-column models. The aim of this physically-based parameterization is to represent the effect of organized turbulent structures (updrafts and downdrafts) on the daytime PBL transport, as it is resolved in Large-Eddy Simulations [LESs]. We find that the terrestrial thermal plume model needs to be modified to satisfyingly account for deep turbulent plumes found in the Martian convective PBL. Our Martian thermal plume model qualitatively and quantitatively reproduces the thermal structure of the daytime PBL on Mars: superadiabatic near-surface layer, mixing layer, and overshoot region at PBL top. This model is coupled to surface layer parameterizations taking ...

  13. Tracking hydrocarbon plume transport and biodegradation at Deepwater Horizon.

    Science.gov (United States)

    Camilli, Richard; Reddy, Christopher M; Yoerger, Dana R; Van Mooy, Benjamin A S; Jakuba, Michael V; Kinsey, James C; McIntyre, Cameron P; Sylva, Sean P; Maloney, James V

    2010-10-08

    The Deepwater Horizon blowout is the largest offshore oil spill in history. We present results from a subsurface hydrocarbon survey using an autonomous underwater vehicle and a ship-cabled sampler. Our findings indicate the presence of a continuous plume of oil, more than 35 kilometers in length, at approximately 1100 meters depth that persisted for months without substantial biodegradation. Samples collected from within the plume reveal monoaromatic petroleum hydrocarbon concentrations in excess of 50 micrograms per liter. These data indicate that monoaromatic input to this plume was at least 5500 kilograms per day, which is more than double the total source rate of all natural seeps of the monoaromatic petroleum hydrocarbons in the northern Gulf of Mexico. Dissolved oxygen concentrations suggest that microbial respiration rates within the plume were not appreciably more than 1 micromolar oxygen per day.

  14. False alarm recognition in hyperspectral gas plume identification

    Energy Technology Data Exchange (ETDEWEB)

    Conger, James L. (San Ramon, CA); Lawson, Janice K. (Tracy, CA); Aimonetti, William D. (Livermore, CA)

    2011-03-29

    According to one embodiment, a method for analyzing hyperspectral data includes collecting first hyperspectral data of a scene using a hyperspectral imager during a no-gas period and analyzing the first hyperspectral data using one or more gas plume detection logics. The gas plume detection logic is executed using a low detection threshold, and detects each occurrence of an observed hyperspectral signature. The method also includes generating a histogram for all occurrences of each observed hyperspectral signature which is detected using the gas plume detection logic, and determining a probability of false alarm (PFA) for all occurrences of each observed hyperspectral signature based on the histogram. Possibly at some other time, the method includes collecting second hyperspectral data, and analyzing the second hyperspectral data using the one or more gas plume detection logics and the PFA to determine if any gas is present. Other systems and methods are also included.

  15. Volcanic ash plume identification using polarization lidar: Augustine eruption, Alaska

    Science.gov (United States)

    Sassen, Kenneth; Zhu, Jiang; Webley, Peter W.; Dean, K.; Cobb, Patrick

    2007-01-01

    During mid January to early February 2006, a series of explosive eruptions occurred at the Augustine volcanic island off the southern coast of Alaska. By early February a plume of volcanic ash was transported northward into the interior of Alaska. Satellite imagery and Puff volcanic ash transport model predictions confirm that the aerosol plume passed over a polarization lidar (0.694 mm wavelength) site at the Arctic Facility for Atmospheric Remote Sensing at the University of Alaska Fairbanks. For the first time, lidar linear depolarization ratios of 0.10 – 0.15 were measured in a fresh tropospheric volcanic plume, demonstrating that the nonspherical glass and mineral particles typical of volcanic eruptions generate strong laser depolarization. Thus, polarization lidars can identify the volcanic ash plumes that pose a threat to jet air traffic from the ground, aircraft, or potentially from Earth orbit.

  16. Destratification induced by bubble plumes as a means to reduce ...

    African Journals Online (AJOL)

    to reduce evaporation from open impoundments. M van Dijk* and SJ van .... The air injection bubble plume system used for water quality applications has been ...... ervoir Evaporation Utilizing Mass Transfer Theory. US Geological. Survey.

  17. Vertically Discontinuous Seismic Signatures From Continuous Thermochemical Plumes

    Science.gov (United States)

    Harris, A. C.; Kincaid, C.; Savage, B.

    2008-12-01

    To interpret seismic signatures associated with mantle upwellings, we must understand the distribution of thermochemical heterogeneities within mantle plumes. Thermochemical heterogeneities are expected to arise within plumes by the incorporation of subducted lithosphere (Eclogite and Harzburgite) that has reached the plume source region (thermal boundary layers in the mantle). We analyze laboratory experiments in conjunction with seismic velocity models to predict the seismic signature of thermochemical plumes. Laboratory experiments are fully three-dimensional and use glucose syrup (Rayleigh number: 106) to model the mantle and a two-layer subducted lithosphere, where composition (viscosity and density) is controlled by water content. Experiments show heterogeneous upwellings with variations in both temperature and composition that are more complex than predicted in previous plume models. Spatial distributions for temperature and composition in representative, repeatable types of thermochemical upwellings are tracked through time, scaled to mantle values and used to calculate predicted seismic velocities. Apparent seismic velocity signals are estimated for patterns in thermochemical heterogeneity with length scales ranging from 1 to 300 km and excess temperatures from 50 to 300°C. Results show that if plumes are purely thermal they can be identified in the usual way, by slow velocities. However, if plumes are a mixture of compositions, as predicted by laboratory models, their velocity structure is more complex. An Ecolgite lens within a plume at ~300km depth with an excess temperature of 250°C can have the same velocity as regular mantle with no excess temperature. A Harzburgite lobe of a plume head (up to half of the plume volume) at 300km depth with an excess temperature of 225°C can have the same Vs as regular mantle with no excess temperature, but can only mask up to 55°C in Vp. Spatial variations in temperature control velocity structure above 300km

  18. Site characterization and petroleum hydrocarbon plume mapping

    Energy Technology Data Exchange (ETDEWEB)

    Ravishankar, K. [Harding Lawson Associates, Houston, TX (United States)

    1996-12-31

    This paper presents a case study of site characterization and hydrocarbon contamination plume mapping/delineation in a gas processing plant in southern Mexico. The paper describes innovative and cost-effective use of passive (non-intrusive) and active (intrusive) techniques, including the use of compound-specific analytical methods for site characterization. The techniques used, on a demonstrative basis, include geophysical, geochemical, and borehole drilling. Geochemical techniques used to delineate the horizontal extent of hydrocarbon contamination at the site include soil gas surveys. The borehole drilling technique used to assess the vertical extent of contamination and confirm geophysical and geochemical data combines conventional hollow-stem auguring with direct push-probe using Geoprobe. Compound-specific analytical methods, such as hydrocarbon fingerprinting and a modified method for gasoline range organics, demonstrate the inherent merit and need for such analyses to properly characterize a site, while revealing the limitations of noncompound-specific total petroleum hydrocarbon analysis. The results indicate that the techniques used in tandem can properly delineate the nature and extent of contamination at a site; often supplement or complement data, while reducing the risk of errors and omissions during the assessment phase; and provide data constructively to focus site-specific remediation efforts. 7 figs.

  19. Evolution of particle size in turbid discharge plumes

    Science.gov (United States)

    2016-06-07

    Evolution of particle size in turbid discharge plumes Paul S. Hill Department of Oceanography Dalhousie University Halifax, Nova Scotia, CANADA B3H...COVERED 00-00-1999 to 00-00-1999 4. TITLE AND SUBTITLE Evolution of particle size in turbid discharge plumes 5a. CONTRACT NUMBER 5b. GRANT...experiment was designed to explore the evolution of disaggregated grain size distribution in a flowing suspension. RESULTS Bulk effective settling

  20. The Communicating Pipe Model for Icy Plumes on Enceladus

    Institute of Scientific and Technical Information of China (English)

    MA Qian-Li; CHEN Chu-Xin

    2009-01-01

    We analyze the communicating pipe model on Enceladus, and predict that Saturn's strong tidal force in Enceladus plays a significant role in the plumes. In this model, the scale of the volcanoes can be evaluated based on the history of the craters and plumes. The correspondence of the data and observation make the model valid for the eruption. So it is imaginable that the tidal force is pulling the liquid out through the communicating pipe while reshaping the surface on Enceladus.

  1. Chemical Plume Detection with an Iterative Background Estimation Technique

    Science.gov (United States)

    2016-05-17

    this paper, we focus on cases where the plume is large (relative to the image ), and provide a method for handling this scenario. The method we develop...the locations of the events, the operation in (11) is a convolution of a binary image with a filter function h. To get an estimate of the probability...background statistics, including the mean and covariance. Diffuse plumes with a large spatial extent are particularly difficult to detect in single- image

  2. Ship emissions measurement in the Arctic by plume intercepts of the Canadian Coast Guard icebreaker Amundsen from the Polar 6 aircraft platform

    Science.gov (United States)

    Aliabadi, Amir A.; Thomas, Jennie L.; Herber, Andreas B.; Staebler, Ralf M.; Leaitch, W. Richard; Schulz, Hannes; Law, Kathy S.; Marelle, Louis; Burkart, Julia; Willis, Megan D.; Bozem, Heiko; Hoor, Peter M.; Köllner, Franziska; Schneider, Johannes; Levasseur, Maurice; Abbatt, Jonathan P. D.

    2016-06-01

    Decreasing sea ice and increasing marine navigability in northern latitudes have changed Arctic ship traffic patterns in recent years and are predicted to increase annual ship traffic in the Arctic in the future. Development of effective regulations to manage environmental impacts of shipping requires an understanding of ship emissions and atmospheric processing in the Arctic environment. As part of the summer 2014 NETCARE (Network on Climate and Aerosols) campaign, the plume dispersion and gas and particle emission factors of effluents originating from the Canadian Coast Guard icebreaker Amundsen operating near Resolute Bay, NU, Canada, were investigated. The Amundsen burned distillate fuel with 1.5 wt % sulfur. Emissions were studied via plume intercepts using the Polar 6 aircraft measurements, an analytical plume dispersion model, and using the FLEXPART-WRF Lagrangian particle dispersion model. The first plume intercept by the research aircraft was carried out on 19 July 2014 during the operation of the Amundsen in the open water. The second and third plume intercepts were carried out on 20 and 21 July 2014 when the Amundsen had reached the ice edge and operated under ice-breaking conditions. Typical of Arctic marine navigation, the engine load was low compared to cruising conditions for all of the plume intercepts. The measured species included mixing ratios of CO2, NOx, CO, SO2, particle number concentration (CN), refractory black carbon (rBC), and cloud condensation nuclei (CCN). The results were compared to similar experimental studies in mid-latitudes. Plume expansion rates (γ) were calculated using the analytical model and found to be γ = 0.75 ± 0.81, 0.93 ± 0.37, and 1.19 ± 0.39 for plumes 1, 2, and 3, respectively. These rates were smaller than prior studies conducted at mid-latitudes, likely due to polar boundary layer dynamics, including reduced turbulent mixing compared to mid-latitudes. All emission factors were in agreement with prior

  3. Theoretical studies on vibrational spectra, thermodynamic properties, detonation properties and pyrolysis mechanism for 1,2-bis(2,4,6-trinitrophenyl) hydrazine.

    Science.gov (United States)

    Xiao-Hong, Li; Rui-Zhou, Zhang; Xian-Zhou, Zhang

    2012-07-01

    The thermal stability and pyrolysis mechanism of 1,2-bis(2,4,6-trinitrophenyl) hydrazine were investigated based on fully optimized molecular geometric structures. The results demonstrate the existence of intramolecular hydrogen bond interactions 1,2-bis(2,4,6-trinitrophenyl) hydrazine. The assigned infrared spectrum was also obtained; the results reveal four main characteristic regions in the calculated IR spectra of the title compound. Detonation velocities (D) and pressures (P) were also evaluated by using Kamlet-Jacobs equations based on the calculated density and heat of formation. Thermal stability and the pyrolysis mechanism of 1,2-bis(2,4,6-trinitrophenyl) hydrazine were investigated by calculating the bond dissociation energies at the B3LYP/6-31 G* level.

  4. Structures of N- (2,3,4,6-Tetra- O-acetyl-β- D-glycosyl) thiocar-bamic Benzoyl Hydrazine

    Institute of Scientific and Technical Information of China (English)

    ZHANG,Shu-Sheng(张书圣); LIN,Jie-Hua(林洁华); JIAN,Fang-Fang(建方方); JIAO,Kui(焦奎)

    2002-01-01

    The crystal structure of N-( 2, 3 , 4 , 6-tetra-O-acetyl- β- D-glycosyl)-thiocarbamic benzoyl hydrazine ( C22 H27 N3O9S) was determined by X-ray diffraction method. The hexopyranosyl ring adopts a chair conformation. All the ring substituents are in the equatorial positions. The acetoxyl-methyl group is in synclinal conformation. The S atom is in synperiplanar conformation while the benzoyl hydrazine moiety is anti-periplanar. The thiocarbamic moiety is almost coplanar with the benzoyl hydrazine group. There are two intramolecular hydrogen bonds and one intermolecular hydrogen bond for each molecule in the crystal structure. The molecules form a network structure through intermolecular hydrogen bonds.

  5. Facile growth of Ag@Pt bimetallic nanorods on electrochemically reduced graphene oxide for an enhanced electrooxidation of hydrazine

    Indian Academy of Sciences (India)

    Jeena S E; Selvaraju T

    2016-03-01

    An efficient transducer was constructed by the direct growth of bimetallic Ag@Pt nanorods (NRDs) on L−tryptophan functionalized electrochemically reduced graphene oxide (L−ERGO) modified electrode using galvanic displacement method for the electrooxidation of hydrazine.Initially, one dimensionalbimetallic Ag@Cu core−shell NRDs were grown on L−ERGO modified electrode by simple seed mediated growth method. Then, the Cu shells at bimetallic NRDs were exchanged by Pt through galvanic displacement method. Accordingly, the synergetic effect produced by the combination of Ag and Pt as NRDs at L−ERGO surface enabled an enhancement in the electrocatalytic efficiency for hydrazine oxidation. L−ERGO supported bimetallic Ag@Pt NRDs were characterised by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and cyclic voltammetric techniques. Finally, the modified electrode was successfully used for the electrooxidation of hydrazine in PB (pH 7.4)with a detection limit of 6*10−7M(SdivN=3). Importantly, the presence of Pt on Ag surface plays a vital role in the electrooxidation of [N2H4] at−0.2 V with an onset potential at−0.5 V where its overpotential has decreased. On the other hand, L−ERGO nanosheets tend to facilitate an effective immobilization of low density Ag seeds (Agseeds) on its surface. Chronoamperometric studies were used to study the linear correlation of [N2H4] between 1 mM and 10 mM. The modified electrode shows a high sensitivity and selectivity for a trace amount of N2H4 in the presence of different interfering cations and anions

  6. Concept for Inclusion of Analytical and Computational Capability in Optical Plume Anomaly Detection (OPAD) for Measurement of Neutron Flux

    Science.gov (United States)

    Patrick, Marshall Clint; Cooper, Anita E.; Powers, W. T.

    2004-01-01

    Researchers are working on many fronts to make possible high-speed, automated classification and quantification of constituent materials in numerous environments. NASA's Marshall Space Flight Center has implemented a system for rocket engine flowfields/plumes. The Optical Plume Anomaly Detector (OPAD) system was designed to utilize emission and absorption spectroscopy for monitoring molecular and atomic particulates in gas plasma. An accompanying suite of tools and analytical package designed to utilize information collected by OPAD is known as the Engine Diagnostic Filtering System (EDiFiS). The current combination of these systems identifies atomic and molecular species and quantifies mass loss rates in H2/O2 rocket plumes. Capabilities for real-time processing are being advanced on several fronts, including an effort to hardware encode components of the EDiFiS for health monitoring and management. This paper addresses the OPAD with its tool suites, and discusses what is considered a natural progression: a concept for taking OPAD to the next logical level of high energy physics, incorporating fermion and boson particle analyses in measurement of neutron flux.

  7. Mapping the Hawaiian plume conduit with converted seismic waves

    Science.gov (United States)

    Li; Kind; Priestley; Sobolev; Tilmann; Yuan; Weber

    2000-06-22

    The volcanic edifice of the Hawaiian islands and seamounts, as well as the surrounding area of shallow sea floor known as the Hawaiian swell, are believed to result from the passage of the oceanic lithosphere over a mantle hotspot. Although geochemical and gravity observations indicate the existence of a mantle thermal plume beneath Hawaii, no direct seismic evidence for such a plume in the upper mantle has yet been found. Here we present an analysis of compressional-to-shear (P-to-S) converted seismic phases, recorded on seismograph stations on the Hawaiian islands, that indicate a zone of very low shear-wave velocity (effects of the Hawaiian plume conduit in the asthenosphere and mantle transition zone with excess temperature of approximately 300 degrees C. Large variations in the transition-zone thickness suggest a lower-mantle origin of the Hawaiian plume similar to the Iceland plume, but our results indicate a 100 degrees C higher temperature for the Hawaiian plume.

  8. THE FLOW PATTERNS OF BUBBLE PLUME IN AN MBBR

    Institute of Scientific and Technical Information of China (English)

    LI Shi-rong; CHENG Wen; WANG Meng; CHEN Chen

    2011-01-01

    The flow patterns of the gas-liquid two-phase flow in a Moving-Bed Biofilm Reactor(MBBR)have a critical effect upon the mass transfer by the convection.Bubble plumes promote unsteadily fluctuating two-phase flows during the aeration.This article studies the unsteady structure of bubble plumes through experiments.The time-serial bubble plume images in various cases of the tank are analyzed.The Recursive Cross Correlation-Particle Image Velocimetry(RCC-PIV)is used to calculate the velocities in those cases,and then the time-serial vortex,the total turbulence intensity,the time-serial streamline are obtained.It is shown that the aspect ratio and the void fraction are the dominant factors influencing the unsteady structure of bubble plumes.When the aspect ratio is unity and the void fraction is high,the bubble plumes see a symmetrical vortex structure with a long residence time,which is beneficial for optimizing the aeration system and enhancing the applied range of bubble plumes.

  9. P- and S-wave delays caused by thermal plumes

    Science.gov (United States)

    Maguire, Ross; Ritsema, Jeroen; van Keken, Peter E.; Fichtner, Andreas; Goes, Saskia

    2016-08-01

    Many studies have sought to seismically image plumes rising from the deep mantle in order to settle the debate about their presence and role in mantle dynamics, yet the predicted seismic signature of realistic plumes remains poorly understood. By combining numerical simulations of flow, mineral-physics constraints on the relationships between thermal anomalies and wave speeds, and spectral-element method based computations of seismograms, we estimate the delay times of teleseismic S and P waves caused by thermal plumes. Wave front healing is incomplete for seismic periods ranging from 10 s (relevant in traveltime tomography) to 40 s (relevant in waveform tomography). We estimate P-wave delays to be immeasurably small (20 s), measurements of instantaneous phase misfit may be more useful in resolving narrow plume conduits. To detect S-wave delays of 0.4-0.8 s and the diagnostic frequency dependence imparted by plumes, it is key to minimize the influence of the heterogeneous crust and upper mantle. We argue that seismic imaging of plumes will advance significantly if data from wide-aperture ocean-bottom networks were available since, compared to continents, the oceanic crust and upper mantle are relatively simple.

  10. Growth and mixing dynamics of mantle wedge plumes

    Science.gov (United States)

    Gorczyk, Weronika; Gerya, Taras V.; Connolly, James A. D.; Yuen, David A.

    2007-07-01

    Recent work suggests that hydrated partially molten thermal-chemical plumes that originate from subducted slab as a consequence of Rayleigh-Taylor instability are responsible for the heterogeneous composition of the mantle wedge. We use a two-dimensional ultrahigh-resolution numerical simulation involving 10 × 109 active markers to anticipate the detailed evolution of the internal structure of natural plumes beneath volcanic arcs in intraoceanic subduction settings. The plumes consist of partially molten hydrated peridotite, dry solid mantle, and subducted oceanic crust, which may compose as much as 12% of the plume. As plumes grow and mature these materials mix chaotically, resulting in attenuation and duplication of the original layering on scales of 1-1000 m. Comparison of numerical results with geological observations from the Horoman ultramafic complex in Japan suggests that mixing and differentiation processes related to development of partially molten plumes above slabs may be responsible for the strongly layered lithologically mixed (marble cake) structure of asthenospheric mantle wedges.

  11. Influence of mass transfer on bubble plume hydrodynamics

    Directory of Open Access Journals (Sweden)

    IRAN E. LIMA NETO

    2016-03-01

    Full Text Available ABSTRACT This paper presents an integral model to evaluate the impact of gas transfer on the hydrodynamics of bubble plumes. The model is based on the Gaussian type self-similarity and functional relationships for the entrainment coefficient and factor of momentum amplification due to turbulence. The impact of mass transfer on bubble plume hydrodynamics is investigated considering different bubble sizes, gas flow rates and water depths. The results revealed a relevant impact when fine bubbles are considered, even for moderate water depths. Additionally, model simulations indicate that for weak bubble plumes (i.e., with relatively low flow rates and large depths and slip velocities, both dissolution and turbulence can affect plume hydrodynamics, which demonstrates the importance of taking the momentum amplification factor relationship into account. For deeper water conditions, simulations of bubble dissolution/decompression using the present model and classical models available in the literature resulted in a very good agreement for both aeration and oxygenation processes. Sensitivity analysis showed that the water depth, followed by the bubble size and the flow rate are the most important parameters that affect plume hydrodynamics. Lastly, dimensionless correlations are proposed to assess the impact of mass transfer on plume hydrodynamics, including both the aeration and oxygenation modes.

  12. On the mechanism of atmospheric pressure plasma plume

    Science.gov (United States)

    Chen, Longwei; Zhao, Peng; Shu, Xingsheng; Shen, Jie; Meng, Yuedong

    2010-08-01

    For the purpose of unveiling the parameters influencing the length of atmospheric pressure plasma plume, an over 165 cm long argon plasma plume is generated in the quartz tube attached to the nozzle of the device. Dependence of plasma length on discharge parameters such as applied voltage, frequency of power supply, and argon gas flow rate was investigated. Experimental results indicated that (a) the applied voltage plays crucial roles on plasma plume length, that is, the plasma plume length exponentially increases with the applied voltage, (b) the plasma plume length increases with frequency, more obviously when the applied voltage is higher, (c) the plasma plume length increases with argon gas flow rate, reaches its maximum at critical value of the gas flow rate, and then decreases again. An evaluation of the physical phenomena involved in streamer propagation, particularly of the energy balance, was investigated. The numerical results were qualitatively consistent with previous experimental results by successfully indicating the high velocity of "plasma bullet" and providing physical mechanism of energy balance determining streamer length.

  13. A Preliminary Model of Infrared Image Generation for Exhaust Plume

    Directory of Open Access Journals (Sweden)

    Fei Mei

    2011-06-01

    Full Text Available Based on the irradiance calculation of all pixels on the focal plane array, a preliminary infrared imaging prediction model of exhaust plume that have considered the geometrical and the thermal resolution of the camera was developed to understanding the infrared characteristics of exhaust plume. In order to compute the irradiance incident on each pixel, the gas radiation transfer path in the plume for the instantaneous field of view corresponds to the pixel was solved by the simultaneous equation of a enclosure cylinder which covers the exhaust plume and the line of sight. Radiance of the transfer path was calculated by radiation transfer equation for nonscattering gas. The radiative properties of combustion needed in the equation was provided by employing Malkmus model with EM2C narrow band database(25cm-1. The pressure, species concentration along the path was determination by CFD analysis. The relative irradiance intensity of each pixel was converted to color in the display according to gray map coding and hot map coding. Infrared image of the exhaust plumes from a subsonic axisymmetric nozzle with different relative position of camera and the plume was predicted with the model. By changing the parameters, such as FOV and space resolution, the image of different imaging system can be predicted.

  14. Implementation of microwave transmissions for rocket exhaust plume diagnostics

    Science.gov (United States)

    Coutu, Nicholas George

    Rocket-launched vehicles produce a trail of exhaust that contains ions, free electrons, and soot. The exhaust plume increases the effective conductor length of the rocket. A conductor in the presence of an electric field (e.g. near the electric charge stored within a cloud) can channel an electric discharge. The electrical conductivity of the exhaust plume is related to its concentration of free electrons. The risk of a lightning strike in-flight is a function of both the conductivity of the body and its effective length. This paper presents an approach that relates the electron number density of the exhaust plume to its propagation constant. Estimated values of the collision frequency and electron number density generated from a numerical simulation of a rocket plume are used to guide the design of the experimental apparatus. Test par meters are identified for the apparatus designed to transmit a signal sweep form 4 GHz to 7 GHz through the exhaust plume of a J-class solid rocket motor. Measurements of the scattering parameters imply that the transmission does not penetrate the plume, but instead diffracts around it. The electron density 20 cm downstream from the nozzle exit is estimated to be between 2.7x1014 m--3 and 5.6x10 15 m--3.

  15. Updated Conceptual Model for the 300 Area Uranium Groundwater Plume

    Energy Technology Data Exchange (ETDEWEB)

    Zachara, John M.; Freshley, Mark D.; Last, George V.; Peterson, Robert E.; Bjornstad, Bruce N.

    2012-11-01

    The 300 Area uranium groundwater plume in the 300-FF-5 Operable Unit is residual from past discharge of nuclear fuel fabrication wastes to a number of liquid (and solid) disposal sites. The source zones in the disposal sites were remediated by excavation and backfilled to grade, but sorbed uranium remains in deeper, unexcavated vadose zone sediments. In spite of source term removal, the groundwater plume has shown remarkable persistence, with concentrations exceeding the drinking water standard over an area of approximately 1 km2. The plume resides within a coupled vadose zone, groundwater, river zone system of immense complexity and scale. Interactions between geologic structure, the hydrologic system driven by the Columbia River, groundwater-river exchange points, and the geochemistry of uranium contribute to persistence of the plume. The U.S. Department of Energy (DOE) recently completed a Remedial Investigation/Feasibility Study (RI/FS) to document characterization of the 300 Area uranium plume and plan for beginning to implement proposed remedial actions. As part of the RI/FS document, a conceptual model was developed that integrates knowledge of the hydrogeologic and geochemical properties of the 300 Area and controlling processes to yield an understanding of how the system behaves and the variables that control it. Recent results from the Hanford Integrated Field Research Challenge site and the Subsurface Biogeochemistry Scientific Focus Area Project funded by the DOE Office of Science were used to update the conceptual model and provide an assessment of key factors controlling plume persistence.

  16. P and S wave delays caused by thermal plumes

    Science.gov (United States)

    Maguire, Ross; Ritsema, Jeroen; van Keken, Peter E.; Fichtner, Andreas; Goes, Saskia

    2016-05-01

    Many studies have sought to seismically image plumes rising from the deep mantle in order to settle the debate about their presence and role in mantle dynamics, yet the predicted seismic signature of realistic plumes remains poorly understood. By combining numerical simulations of flow, mineral-physics constraints on the relationships between thermal anomalies and wave speeds, and spectral-element method based computations of seismograms, we estimate the delay times of teleseismic S and P waves caused by thermal plumes. Wavefront healing is incomplete for seismic periods ranging from 10 s (relevant in traveltime tomography) to 40 s (relevant in waveform tomography). We estimate P wave delays to be immeasurably small ( 20 s), measurements of instantaneous phase misfit may be more useful in resolving narrow plume conduits. To detect S wave delays of 0.4-0.8 s and the diagnostic frequency dependence imparted by plumes, it is key to minimize the influence of the heterogeneous crust and upper mantle. We argue that seismic imaging of plumes will advance significantly if data from wide-aperture ocean-bottom networks were available since, compared to continents, the oceanic crust and upper mantle is relatively simple.

  17. Hydrazine-Free Solution-Deposited CuIn(S,Se)2 Solar Cells by Spray Deposition of Metal Chalcogenides

    Energy Technology Data Exchange (ETDEWEB)

    Arnou, Panagiota; van Hest, Maikel F. A. M.; Cooper, Carl S.; Malkov, Andrei V.; Walls, John M.; Bowers, Jake W.

    2016-05-18

    Solution processing of semiconductors, such as CuInSe2 and its alloys (CIGS), can significantly reduce the manufacturing costs of thin film solar cells. Despite the recent success of solution deposition approaches for CIGS, toxic reagents such as hydrazine are usually involved, which introduce health and safety concerns. Here, we present a simple and safer methodology for the preparation of high-quality CuIn(S, Se)2 absorbers from metal sulfide solutions in a diamine/dithiol mixture. The solutions are sprayed in air, using a chromatography atomizer, followed by a postdeposition selenization step. Two different selenization methods are explored resulting in power conversion efficiencies of up to 8%.

  18. Change in plant cycle chemistry from hydrazine/phosphate to amine/polyamine treatment in an industrial power station

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, T.; Besl, G. [TUeV SUeD Industrie Service GmbH, Muenchen (Germany); Stecklina, M. [MD Papier GmbH, Dachau (Germany)

    2007-08-15

    In an industrial power station with several natural circulation boilers (permissible operation pressure 13.6 MPa), raw water treatment via demineralization, condensate polishing and thermal feedwater degasification, the cycle chemistry was changed from hydrazine/phosphate to amine/polyamine treatment. The modification was supervised by TUeV SUeD with several water chemical analyses of the water/steam circuit. No problematic water conditions were found during the investigations. Fewer condensate impurities and a reduced amount of boiler blowdown can be stated as positive results of the transition to the polyamine treatment. (orig.)

  19. Tests for the mutagenic action of a number of chemicals on Haemophilus influenzae with special emphasis on hydrazine

    Energy Technology Data Exchange (ETDEWEB)

    Kimball, R.F.; Hirsch, B.F.

    1975-01-01

    A number of chemicals have been tested for their ability to produce novobiocin-resistant mutants in Haemophilus influenzae. Of these, hydrazine (HZ) proved unique because it induced a fairly high incidence of mutation without killing significant numbers of cells at concentrations ranging over nearly four orders of magnitude. Moreover, its dose--effect curve increased very slowly initially and reached a relatively low maximum. It is suggested that HZ may be acting as both a mutagen and an antimutagen in this system. (auth)

  20. Effects of ethanolamine, pH change, and increased hydrazine levels on deposit-covered alloy 600 and brass corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Barkatt, A.; Labuda, E.; Wilder, D.M. [Catholic Univ. of America, Washington, DC (United States). Dept. of Chemistry; Smialowska, S.; Rebak, R.B. [Ohio State Univ., Columbus, OH (United States). Fontana Corrosion Center; Cherepakhov, G. [Consolidated Edison Co. of New York, Inc., New York, NY (United States); Burns, R.J. [Consolidated Edison Co. of New York, Inc., Buchanan, NY (United States)

    1997-09-01

    Chemical dissolution tests and electrochemical tests were carried out on alloy 600 (UNS N06600) specimens covered with synthetic deposit simulating the tube deposits in the steam generators at Indian Point 2 Station in Buchanan, New York. The tests showed that the introduction of ethanolamine (ETA) and a moderate increase in pH gave rise to lower corrosion rates, but enhancement of hydrazine levels caused them to rise. In the case of brass, both types of tests showed that raising the pH caused the corrosion rates to increase, but the introduction of ETA led to a mild decrease in these rates.

  1. The interaction of hydrazine with an Rh(1 1 1) surface as a model for adsorption to rhodium nanoparticles: A dispersion-corrected DFT study

    Energy Technology Data Exchange (ETDEWEB)

    He, Yan Bin [School of Chemistry and Materials Science, Shanxi Normal University, Linfen 041004 (China); Pharmaceutical Department, Changzhi Medical College, Changzhi 046000 (China); Jia, Jian Feng, E-mail: jiajf@dns.sxnu.edu.cn [School of Chemistry and Materials Science, Shanxi Normal University, Linfen 041004 (China); Wu, Hai Shun, E-mail: wuhs@mail.sxnu.edu.cn [School of Chemistry and Materials Science, Shanxi Normal University, Linfen 041004 (China)

    2015-02-01

    Highlights: • We propose a model suitable for simulating the adsorption of hydrazine on rhodium nanoparticles. • We found that inclusion of dispersion correction results in significant enhancement for the adsorption to the Rh(1 1 1) surface. • Nanoparticles surface with lower-coordinated sites are more reactive than those with almost saturated surface sites. - Abstract: In recent years, metal nanoparticles were found to be excellent catalysts for hydrogen generation from hydrazine for chemical hydrogen storage. In order to gain a better understanding of these catalytic systems, we have simulated the adsorption of hydrazine on rhodium nanoparticles surfaces by density functional theory (DFT) calculations with dispersion correction, DFT-D3 in the method of Grimme. The rhodium nanoparticles were modeled by the Rh(1 1 1) surface, in addition, the adsorptions at corners and edges sites of nanoparticles were considered by using rhodium adatoms on the surfaces. The calculations showed that hydrazine binds most strongly to the edge of nanoparticle with adsorption energy of −2.48 eV, where the hydrazine bridges adatoms of edge with the molecule twisted to avoid a cis structure; similar adsorption energy was found at the corner of nanoparticle, where the hydrazine bridges corner atom and surface atom with gauche configuration. However, we found that inclusion of the dispersion correction results in significant enhancement of molecule–substrate binding, thereby increasing the adsorption energy, especially the adsorption to the Rh(1 1 1) surface. The results demonstrate that the surface structure is a key factor to determine the thermodynamics of adsorption, with low coordinated atoms which providing sites of strong adsorption from the surface.

  2. Evidence for melt channelization in Galapagos plume-ridge interaction

    Science.gov (United States)

    Mittal, T.; Richards, M. A.

    2015-12-01

    Many present-day hot spots are located within ~ 1000 km of a mid-ocean ridge, either currently or in the geologic past, leading to frequent interaction between these two magmatic regimes. The consequent plume-ridge interactions provide a unique opportunity to test models for asthenosphere-lithosphere dynamics, with the plume acting as a tracer fluid in the problem, and excess magmatism reflecting otherwise unsampled sub-surface phenomena. Galapagos is an off-ridge hotspot with the mantle plume located ~150-250 km south of the plate boundary. Plume-ridge interaction in Galapagos is expressed by the formation of volcanic lineaments of islands and seamounts - e.g., the Wolf-Darwin lineament (WDL) - providing a direct probe of the plume-ridge interaction process, especially in regards to geochemical data. Although several models have been proposed to explain plume-ridge interaction in Galapagos, none adequately explain the observed characteristics, especially the WDL. In particular, predicted lithospheric fault orientations and melt density considerations appear at odds with observations, suggesting that lithospheric extension is not the primary process for formation of these islands. Other off-ridge hotspots interacting with nearby spreading ridges, such as Reunion and Louisville, also exhibit volcanic lineaments linking the plume and the ridge. Thus these lineament-type features are a common outcome of plume-ridge interaction that are indicative of the underlying physics. We propose that the lineaments are surface expressions of narrow sub-lithospheric melt channels focused towards the spreading ridge. These channels should form naturally due to the reactive infiltration instability in a two-phase flow of magma and solid mantle as demonstrated in two-phase flow simulations (e.g., Katz & Weatherley 2012). For Galapagos, we show that melt channels can persist thermodynamically over sufficient length-scales to link the plume and nearby ridge segments. We also show that

  3. Hydrothermal plume anomalies along the Central Indian Ridge

    Institute of Scientific and Technical Information of China (English)

    ZHU Jian; LIN Jian; GUO ShiQin; CHEN YongShun

    2008-01-01

    Water column turbidity and temperature were investigated along the Central Indian Ridge (CIR) from 25°19'S to 23°48'S during a December 2005 cruise on board Chinese P/V DayangYihao.Measurements were made using NOAA's MAPR (Miniature Autonomous Plume Recorder) sensors during CTD casts,TV grabber operations,and tow-yo profiles,yielding the following results on hydrothermal plume anomalies:(1) Strong hydrothermal turbidity and temperature anomalies were recorded over the pre-viously discovered Kairei (25°19.2'S,70°02.4'E) and Edmond (23°52.7'S,69°35.8"E) vent fields,with the plume anomalies concentrated at depths of 2150-2300 m and 2700-2900 m,respectively.The maxi-mum height of the turbidity anomalies near the Kairei vent field recorded in December 2005 was slightly below 2100 m,which is consistent with the plume depth measured in June 2001,indicating that the Kairei plume may have maintained its buoyancy flux in the intervening 4.5 years.(2) The water column beneath the Kairei plume has background anomalies of about 0.005△NTU,whereas no such back-ground turbidity anomalies were observed below the Edmond hydrothermal plume.(3) No visible tur-bidity anomalies were detected from 24°42'S to 24°12'S including the Knorr Seamount.Thus 24°12'S marks the southern end of the hydrothermal plume.(4) Significant turbidity anomalies were observed at four individual sections from 24°12'S to 23°56'S at the depth of 2500-3000 m along the eastern rift valley wall.Whether the individual sections of anomalies are connected is still unknown due to the absence of data at the intervening gaps.If the four sections are connected with each other and are linked to the Edmond vent field farther to the north,the total along-axis length of the plume anomaly would be more than 37 km,implying a plume incidence value Ph of 0.38,greater than the predicted Ph of 0.21-0.25 based on the spreading rate of the Central Indian Ridge.

  4. Studies of the Kuwait oil fire plume during midsummer 1991

    Science.gov (United States)

    Daum, P. H.; Al-Sunaid, A.; Busness, K. M.; Hales, J. M.; Mazurek, M.

    1993-01-01

    This paper reports aircraft observations of the Kuwait oil fire plume conducted during the period July 31-August 17, 1991. During this study the plume was transported almost exclusively to the south of Kuwait over the Persian Gulf and the Arabian Peninsula. The plume base was generally found to be well above the surface, in some cases as high as 1-2 km; plume tops did not exceed 5 km. Aerosol mass (based on measured aerosol constituents) in the central section of the plume, ca. 150-200 km downwind of the source region, was found to be >500 μg/m3, with number densities in the size range (approximate) 0.2 carbon, and organic carbon. Sodium chloride constituted a surprisingly large component of the soluble inorganic mass. The aerosol particles appeared to function as good cloud condensation nuclei, with a large fraction of accumulation mode particles (by number) activated at a supersaturation of 0.6%. Under conditions in which the plume was relatively compact, transmittance of solar radiation to the surface was only 10-20%. Plume albedo was observed to be as low as 2-3% close to the source region, consistent with the high elemental-carbon concentrations present in the plume. Trace gas concentrations were consistent with fuel composition and with current knowledge of atmospheric chemical processes. Sulfur dioxide concentrations close to the source region were found to be as high as 300-400 ppb. The emissions factor for S (expressed as a percentage) was estimated to be 1.8%, which is consistent with estimates of a fuel sulfur content of 2-2.5%. SO2 was found to be only slowly oxidized (<1%/h). Nitrogen oxide concentrations were found to be quite low (<50 ppb near the source, decreasing to 1-2 ppb well downwind), which is consistent with a crude oil nitrogen source. Despite relatively low concentrations, sufficient NOx was present to act as a catalyst to generate excess ozone in the plume as the plume was transported downwind and dispersed.

  5. ELECTRICAL TECHNIQUES FOR ENGINEERING APPLICATIONS.

    Science.gov (United States)

    Bisdorf, Robert J.

    1985-01-01

    Surface electrical geophysical methods have been used in such engineering applications as locating and delineating shallow gravel deposits, depth to bedrock, faults, clay zones, and other geological phenomena. Other engineering applications include determining water quality, tracing ground water contaminant plumes and locating dam seepages. Various methods and electrode arrays are employed to solve particular geological problems. The sensitivity of a particular method or electrode array depends upon the physics on which the method is based, the array geometry, the electrical contrast between the target and host materials, and the depth to the target. Each of the available electrical methods has its own particular advantages and applications which the paper discusses.

  6. Coordinated sensor cueing for chemical plume detection

    Science.gov (United States)

    Abraham, Nathan J.; Jensenius, Andrea M.; Watkins, Adam S.; Hawthorne, R. Chad; Stepnitz, Brian J.

    2011-05-01

    This paper describes an organic data fusion and sensor cueing approach for Chemical, Biological, Radiological, and Nuclear (CBRN) sensors. The Joint Warning and Reporting Network (JWARN) uses a hardware component referred to as the JWARN Component Interface Device (JCID). The Edgewood Chemical and Biological Center has developed a small footprint and open architecture solution for the JCID capability called JCID-on-a-Chip (JoaC). The JoaC program aims to reduce the cost and complexity of the JCID by shrinking the necessary functionality down to a small single board computer. This effort focused on development of a fusion and cueing algorithm organic to the JoaC hardware. By embedding this capability in the JoaC, sensors have the ability to receive and process cues from other sensors without the use of a complex and costly centralized infrastructure. Additionally, the JoaC software is hardware agnostic, as evidenced by its drop-in inclusion in two different system-on-a-chip platforms including Windows CE and LINUX environments. In this effort, a partnership between JPM-CA, JHU/APL, and the Edgewood Chemical and Biological Center (ECBC), the authors implemented and demonstrated a new algorithm for cooperative detection and localization of a chemical agent plume. This experiment used a pair of mobile Joint Services Lightweight Standoff Chemical Agent Detector (JSLSCAD) units which were controlled by fusion and cueing algorithms hosted on a JoaC. The algorithms embedded in the JoaC enabled the two sensor systems to perform cross cueing and cooperatively form a higher fidelity estimate of chemical releases by combining sensor readings. Additionally, each JSLSCAD had the ability to focus its search on smaller regions than those required by a single sensor system by using the cross cue information from the other sensor.

  7. Constraining the Enceladus plume using numerical simulation and Cassini data

    Science.gov (United States)

    Yeoh, Seng Keat; Li, Zheng; Goldstein, David B.; Varghese, Philip L.; Levin, Deborah A.; Trafton, Laurence M.

    2017-01-01

    Since its discovery, the Enceladus plume has been subjected to intense study due to the major effects that it has on the Saturnian system and the window that it provides into the interior of Enceladus. However, several questions remain and we attempt to answer some of them in this work. In particular, we aim to constrain the H2O production rate from the plume, evaluate the relative importance of the jets and the distributed sources along the Tiger Stripes, and make inferences about the source of the plume by accurately modeling the plume and constraining the model using the Cassini INMS and UVIS data. This is an extension of a previous work (Yeoh, S.K., et al. [2015] Icarus, 253, 205-222) in which we only modeled the collisional part of the Enceladus plume and studied its important physical processes. In this work, we propagate the plume farther into space where the flow has become free-molecular and the Cassini INMS and UVIS data were sampled. Then, we fit this part of the plume to the INMS H2O density distributions sampled along the E3, E5 and E7 trajectories and also compare some of the fit results with the UVIS measurements of the plume optical depth collected during the solar occultation observation on 18 May 2010. We consider several vent conditions and source configurations for the plume. By constraining our model using the INMS and UVIS data, we estimate H2O production rates of several hundred kgs-1: 400-500 kg/s during the E3 and E7 flybys and ∼900 kg/s during the E5 flyby. These values agree with other estimates and are consistent with the observed temporal variability of the plume over the orbital period of Enceladus (Hedman, M.M., et al. [2013] Nature, 500, 182-184). In addition, we determine that one of the Tiger Stripes, Cairo, exhibits a local temporal variability consistent with the observed overall temporal variability of the plume. We also find that the distributed sources along the Tiger Stripes are likely dominant while the jets provide a

  8. Backward Planetary Protection Issues and Possible Solutions for Icy Plume Sample Return Missions from Astrobiological Targets

    Science.gov (United States)

    Yano, Hajime; McKay, Christopher P.; Anbar, Ariel; Tsou, Peter

    The recent report of possible water vapor plumes at Europa and Ceres, together with the well-known Enceladus plume containing water vapor, salt, ammonia, and organic molecules, suggests that sample return missions could evolve into a generic approach for outer Solar System exploration in the near future, especially for the benefit of astrobiology research. Sampling such plumes can be accomplished via fly-through mission designs, modeled after the successful Stardust mission to capture and return material from Comet Wild-2 and multiple, precise trajectory controls of the Cassini mission to fly through Enceladus’ plume. The proposed LIFE (Life Investigation For Enceladus) mission to Enceladus, which would sample organic molecules from the plume of that apparently habitable world, provides one example of the appealing scientific return of such missions. Beyond plumes, the upper atmosphere of Titan could also be sampled in this manner. The SCIM mission to Mars, also inspired by Stardust, would sample and return aerosol dust in the upper atmosphere of Mars and thus extends this concept even to other planetary bodies. Such missions share common design needs. In particular, they require large exposed sampler areas (or sampler arrays) that can be contained to the standards called for by international planetary protection protocols that COSPAR Planetary Protection Policy (PPP) recommends. Containment is also needed because these missions are driven by astrobiologically relevant science - including interest in organic molecules - which argues against heat sterilization that could destroy scientific value of samples. Sample containment is a daunting engineering challenge. Containment systems must be carefully designed to appropriate levels to satisfy the two top requirements: planetary protection policy and the preserving the scientific value of samples. Planning for Mars sample return tends to center on a hermetic seal specification (i.e., gas-tight against helium escape

  9. Enceladus Plume Structure and Time Variability: Comparison of Cassini Observations.

    Science.gov (United States)

    Teolis, Ben D; Perry, Mark E; Hansen, Candice J; Waite, J Hunter; Porco, Carolyn C; Spencer, John R; Howett, Carly J A

    2017-09-05

    During three low-altitude (99, 66, 66 km) flybys through the Enceladus' plume in 2010 and 2011, Cassini's ion neutral mass spectrometer (INMS) made its first high spatial resolution measurements of the plume's gas density and distribution, detecting in situ the individual gas jets within the broad plume. Since those flybys, more detailed Imaging Science Subsystem (ISS) imaging observations of the plume's icy component have been reported, which constrain the locations and orientations of the numerous gas/grain jets. In the present study, we used these ISS imaging results, together with ultraviolet imaging spectrograph stellar and solar occultation measurements and modeling of the three-dimensional structure of the vapor cloud, to constrain the magnitudes, velocities, and time variability of the plume gas sources from the INMS data. Our results confirm a mixture of both low and high Mach gas emission from Enceladus' surface tiger stripes, with gas accelerated as fast as Mach 10 before escaping the surface. The vapor source fluxes and jet intensities/densities vary dramatically and stochastically, up to a factor 10, both spatially along the tiger stripes, and over time between flyby observations. This complex spatial variability and dynamics may result from time-variable tidal stress fields interacting with subsurface fissure geometry and tortuosity beyond detectability, including changing gas pathways to the surface, and fluid flow and boiling in response evolving lithostatic stress conditions. The total plume gas source has 30% uncertainty depending on the contributions assumed for adiabatic and nonadiabatic gas expansion/acceleration to the high Mach emission. The overall vapor plume source rate exhibits stochastic time variability up to a factor ∼5 between observations, reflecting that found in the individual gas sources/jets. Key Words: Cassini at saturn-Geysers-Enceladus-Gas dynamics-Icy satellites. Astrobiology 17, xxx-xxx.

  10. Hydrogeophysical investigations of the former S-3 ponds contaminant plumes

    Energy Technology Data Exchange (ETDEWEB)

    Revil, Andre [ORNL; Skold, Magnus E [ORNL; Karaoulis, Marios [Colorado School of Mines, Golden; Schmutz, Myriam [Institut Polytechnique de Bordeaux; Hubbard, Susan S [Lawrence Berkeley National Laboratory (LBNL); Mehlhorn, Tonia L [ORNL; Watson, David B [ORNL

    2013-01-01

    At the Oak Ridge Integrated Field Research Challenge site, near Oak Ridge, Tennessee, contaminants from the former S-3 ponds have infiltrated the shallow saprolite for over 60 years. Two- and three-dimensional DC-resistivity tomography is used to characterize the number and location of the main contaminant plumes, which include high concentration of nitrate. These contaminant plumes have typically an electrical resistivity in the range 2 20 ohm-m while the background saprolite resistivity is in the range 60 120 ohm-m, so the difference of resistivity can be easily mapped using DC-resistivity tomography to locate the contaminant pathways. We develop a relationship to derive the in situ nitrate concentrations from the 3D resistivity tomograms accounting for the effect of surface conductivity. The footprint of the contamination upon the resistivity is found to be much stronger than the local variations associated with changes in the porosity and the clay content. With this method, we identified a total of five main plumes (termed CP1 to CP5). Plume CP2 corresponds to the main plume in terms of nitrate concentration ( 50,000 ). We also used an active time constrained approach to perform time-lapse resistivity tomography over a section crossing the plumes CP1 and CP2. The sequence of tomograms is used to determine the changes in the nitrate concentrations associated with infiltration of fresh (meteoritic) water from a perched aquifer. This study highlights the importance of accounting for surface conductivity when characterizing plume distributions in clay-rich subsurface systems.

  11. Detection of Copper(II) Ions Using Glycine on Hydrazine-Adsorbed Gold Nanoparticles via Raman Spectroscopy

    Science.gov (United States)

    Ly, Nguyễn Hoàng; Seo, Chulhun; Joo, Sang-Woo

    2016-01-01

    A facile, selective, and sensitive detection method for the Cu2+ ions in environmental and biological solutions has been newly developed by observing the unique CN stretching peaks at ~2108 cm−1 upon the dissociative adsorption of glycine (GLY) in hydrazine buffer on gold nanoparticles (AuNPs). The relative abundance of Cu species on AuNPs was identified from X-ray photoelectron spectroscopy analysis. UV-Vis spectra also indicated that the Au particles aggregated to result in the color change owing to the destabilization induced by the GLY-Cu2+ complex. The CN stretching band at ~2108 cm−1 could be observed to indicate the formation of the CN species from GLY on the hydrazine-covered AuNP surfaces. The other ions of Fe3+, Fe2+, Hg2+, Mg2+, Mn2+, Ni2+, Zn2+, Cr3+, Co2+, Cd2+, Pb2+, Ca2+, NH4+, Na+, and K+ at high concentrations of 50 µM did not produce such spectral changes. The detection limit based on the CN band for the determination of the Cu2+ ion could be estimated to be as low as 500 nM in distilled water and 1 µM in river water, respectively. We attempted to apply our method to estimate intracellular ion detection in cancer cells for more practical purposes. PMID:27792178

  12. French airborne lidar measurements for Eyjafjallajökull ash plume survey

    Directory of Open Access Journals (Sweden)

    P. Chazette

    2012-08-01

    Full Text Available An Ultra-Violet Rayleigh-Mie lidar has been integrated aboard the French research aircraft Falcon20 in order to monitor the ash plume emitted by the Eyjafjallajökul volcano in April–May 2010. Three operational flights were carried out on 21 April, 12 and 16 May 2010 inside French, Spanish and British air spaces, respectively. The original purpose of the flights was to provide the French civil aviation authorities with objective information on the presence and location of the ash plume. The present paper presents the results of detailed analyses elaborated after the volcano crisis. They bear on the structure of the ash clouds and their optical properties such as the extinction coefficient and the lidar ratio. Lidar ratios were measured in the range of 43 to 50 sr, in good agreement with the ratios derived from ground-based lidar near Paris (France in April 2010 (~48 sr. The ash signature in terms of particulate depolarization was consistent during all flights (between 34 ± 3 % and 38 ± 3%. Such a value seems to be a good identification parameter for volcanic ash. Using specific cross-sections between 0.19 and 1.1 m2 g−1, the minimum (maximal mass concentrations in the ash plumes derived for the flights on 12 and 16 May were 140 (2300 and 250 (1500 μg m−3, respectively. It may be rather less than, or of the order of the critical level of damage (2 mg m−3 for the aircraft engines, but well above the 200 μg m−3 warning level.

  13. French airborne lidar measurements for Eyjafjallajökull ash plume survey

    Directory of Open Access Journals (Sweden)

    P. Chazette

    2012-03-01

    Full Text Available An Ultra-Violet Rayleigh-Mie lidar has been integrated aboard the French research aircraft Falcon 20 in order to monitor the ash plume emitted by the Eyjafjallajökul volcano in April–May 2010. Three operational flights were carried out on 21 April, 12 and 16 May 2010 inside French, Spanish and British air spaces, respectively. The original purpose of the flights was to provide the French civil aviation authorities with objective information on the presence and location of the ash plume. The present paper presents the results of detailed analyses elaborated after the volcano crisis. They bear on the structure of the ash clouds and their optical properties such as ash extinction coefficient and lidar ratio. Lidar ratios were measured in the range of 33 to 48 sr, in good agreement with the ratios derived from ground-based lidar measurements performed near Paris (France in April 2010 (∼47 sr. The ash signature in terms of particulate depolarization was consistent around 45 ± 7% during all flights. Such a value seems to be a good identification parameter for ash. Using specific cross-sections between 0.29 and 1.1 m2 g−1, the minimum (maximal mass concentrations in the ash plumes are derived for the flights on 12 and 16 May. They were 190 (2300 and 270 (1600 μg m−3, respectively. It may be rather less than, or of the order of the critical level of damage (2 mg m−3 for the aircraft engines, but well above the 200 μg m−3 warning level.

  14. New PCR primers targeting hydrazine synthase and cytochrome c biogenesis proteins in anammox bacteria.

    Science.gov (United States)

    Zhou, Zhichao; Chen, Jing; Meng, Han; Dvornyk, Volodymyr; Gu, Ji-Dong

    2017-02-01

    PCR primers targeting genes encoding the two proteins of anammox bacteria, hydrazine synthase and cytochrome c biogenesis protein, were designed and tested in this study. Three different ecotypes of samples, namely ocean sediments, coastal wetland sediments, and wastewater treatment plant (WWTP) samples, were used to assess the primer efficiency and the community structures of anammox bacteria retrieved by 16S ribosomal RNA (rRNA) and the functional genes. Abundances of hzsB gene of anammox bacteria in South China Sea (SCS) samples were significantly correlated with 16S rRNA gene by qPCR method. And hzsB and hzsC gene primer pair hzsB364f-hzsB640r and hzsC745f-hzsC862r in combination with anammox bacterial 16S rRNA gene primers were recommended for quantifying anammox bacteria. Congruent with 16S rRNA gene-based community study, functional gene hzsB could also delineate the coastal-ocean distributing pattern, and seawater depth was positively associated with the diversity and abundance of anammox bacteria from shallow- to deep-sea. Both hzsC and ccsA genes could differentiate marine samples between deep and shallow groups of the Scalindua sp. clades. As for WWTP samples, non-Scalindua anammox bacteria reflected by hzsB, hzsC, ccsA, and ccsB gene-based libraries showed a similar distribution pattern with that by 16S rRNA gene. NH4(+) and NH4(+)/Σ(NO3(-) + NO2(-)) positively correlated with anammox bacteria gene diversity, but organic matter contents correlated negatively with anammox bacteria gene diversity in SCS. Salinity was positively associated with diversity indices of hzsC and ccsB gene-harboring anammox bacteria communities and could potentially differentiate the distribution patterns between shallow- and deep-sea sediment samples. SCS surface sediments harbored considerably diverse community of Scalindua. A new Mai Po clade representing coastal estuary wetland anammox bacteria group based on 16S rRNA gene phylogeny is proposed. Existence of anammox

  15. Near-field entrainment in black smoker plumes

    Science.gov (United States)

    Smith, J. E.; Germanovich, L. N.; Lowell, R. P.

    2013-12-01

    In this work, we study the entrainment rate of the ambient fluid into a plume in the extreme conditions of hydrothermal venting at ocean floor depths that would be difficult to reproduce in the laboratory. Specifically, we investigate the flow regime in the lower parts of three black smoker plumes in the Main Endeavour Field on the Juan de Fuca Ridge discharging at temperatures of 249°C, 333°C, and 336°C and a pressure of 21 MPa. Such flow conditions are typical for ocean floor hydrothermal venting but would be difficult to reproduce in the laboratory. The centerline temperature was measured at several heights in the plume above the orifice. Using a previously developed turbine flow meter, we also measured the mean flow velocity at the orifice. Measurements were conducted during dives 4452 and 4518 on the submersible Alvin. Using these measurements, we obtained a range of 0.064 - 0.068 for values of the entrainment coefficient α, which is assumed constant near the orifice. This is half the value of α ≈ 0.12 - 0.13 that would be expected for plume flow regimes based on the existing laboratory results and field measurements in lower temperature and pressure conditions. In fact, α = 0.064 - 0.068 is even smaller than the value of α ≈ 0.075 characteristic of jet flow regimes and appears to be the lowest reported in the literature. Assuming that the mean value α = 0.066 is typical for hydrothermal venting at ocean floor depths, we then characterized the flow regimes of 63 black smoker plumes located on the Endeavor Segment of the Juan de Fuca Ridge. Work with the obtained data is ongoing, but current results indicate that approximately half of these black smokers are lazy in the sense that their plumes exhibit momentum deficits compared to the pure plume flow that develops as the plume rises. The remaining half produces forced plumes that show the momentum excess compared to the pure plumes. The lower value of the entrainment coefficient has important

  16. 液体火箭发动机尾焰红外辐射计算方法%Calculation Method on Infrared Radiation of Liquid Rocket Exhaust Plume

    Institute of Scientific and Technical Information of China (English)

    王大锐; 张楠; 葛明和

    2015-01-01

    针对液体火箭发动机尾焰红外辐射传输方程计算方法、气体辐射参数计算方法以及发动机尾焰红外辐射一体化数值计算研究进行归纳总结。提出发展适用性更广的尾焰红外辐射传输方程计算方法,建立气体光谱数据库及加快开展高精度的尾焰一体化计算研究。%The liquid rocket engine exhaust plume infrared radiation transfer equation calculation method, gas parameters of radiation calculation method and research on the integration numerical calculation of infrared radiation of engine exhaust plume are summarized. The author proposes to develop an exhaust plume infrared radiation transfer equation calculation method with more applicability, establish gas spectrum database and speed up research on the high precision integration calculation of exhaust plume.

  17. AATSR Based Volcanic Ash Plume Top Height Estimation

    Science.gov (United States)

    Virtanen, Timo H.; Kolmonen, Pekka; Sogacheva, Larisa; Sundstrom, Anu-Maija; Rodriguez, Edith; de Leeuw, Gerrit

    2015-11-01

    The AATSR Correlation Method (ACM) height estimation algorithm is presented. The algorithm uses Advanced Along Track Scanning Radiometer (AATSR) satellite data to detect volcanic ash plumes and to estimate the plume top height. The height estimate is based on the stereo-viewing capability of the AATSR instrument, which allows to determine the parallax between the satellite's nadir and 55◦ forward views, and thus the corresponding height. AATSR provides an advantage compared to other stereo-view satellite instruments: with AATSR it is possible to detect ash plumes using brightness temperature difference between thermal infrared (TIR) channels centered at 11 and 12 μm. The automatic ash detection makes the algorithm efficient in processing large quantities of data: the height estimate is calculated only for the ash-flagged pixels. Besides ash plumes, the algorithm can be applied to any elevated feature with sufficient contrast to the background, such as smoke and dust plumes and clouds. The ACM algorithm can be applied to the Sea and Land Surface Temperature Radiometer (SLSTR), scheduled for launch at the end of 2015.

  18. Sewage outfall plume dispersion observations with an autonomous underwater vehicle.

    Science.gov (United States)

    Ramos, P; Cunha, S R; Neves, M V; Pereira, F L; Quintaneiro, I

    2005-01-01

    This work represents one of the first successful applications of Autonomous Underwater Vehicles (AUVs) for interdisciplinary coastal research. A monitoring mission to study the shape and estimate the initial dilution of the S. Jacinto sewage outfall plume using an AUV was performed on July 2002. An efficient sampling strategy enabling greater improvements in spatial and temporal range of detection demonstrated that the sewage effluent plume can be clearly traced using naturally occurring tracers in the wastewater. The outfall plume was found at the surface highly influenced by the weak stratification and low currents. Dilution varying with distance downstream was estimated from the plume rise over the outfall diffuser until a nearly constant value of 130:1, 60 m from the diffuser, indicating the near field end. Our results demonstrate that AUVs can provide high-quality measurements of physical properties of effluent plumes in a very effective manner and valuable considerations about the initial mixing processes under real oceanic conditions can be further investigated.

  19. A cold plasma plume with a highly conductive liquid electrode

    Institute of Scientific and Technical Information of China (English)

    Chen Guang-Liang; Chen Shi-gua; Chen Wen-Xing; Yang Si-Ze

    2008-01-01

    A cold dielectric barrier discharge (DBD) plasma plume with one highly conductive liquid electrode has been developed to treat thermally sensitive materials, and its preliminary discharging characteristics have been studied. The averaged electron temperature and density is estimated to be 0.6eV and 1011/cm3, respectively. The length of plasma plume can reach 5cm with helium gas (He), and the conductivity of the outer electrode affects the plume length obviously. This plasma plume could be touched by bare hand without causing any burning or painful sensation,which may provide potential application for safe aseptic skin care. Moreover, the oxidative particles (e.g., OH, O*03) in the downstream oxygen (02) gas of the plume have been applied to treat the landfill leachate. The results show that the activated 02 gas can degrade the landfill leachate effectively, and the chemical oxygen demand (COD),conductivity, biochemical oxygen demand (BOD), and suspended solid (SS) can be decreased by 52%, 57%, 76% and 92%, respectively.

  20. Solar coronal plumes and the fast solar wind

    CERN Document Server

    Dwivedi, B N

    2015-01-01

    The spectral profiles of the coronal Ne viii line at 77 nm have different shapes in quiet-Sun regions and coronal holes (CHs). A single Gaussian fit of the line profile provides an adequate approximation in quiet-Sun areas, whereas a strong shoulder on the long-wavelength side is a systematic feature in CHs. Although this has been noticed since 1999, no physical reason for the peculiar shape could be given. In an attempt to identify the cause of this peculiarity, we address three problems that could not be conclusively resolved in a review article by a study team of the International Space Science Institute (ISSI; Wilhelm et al. 2011) : (1) The physical processes operating at the base and inside of plumes as well as their interaction with the solar wind (SW). (2) The possible contribution of plume plasma to the fast SW streams. (3) The signature of the first-ionization potential (FIP) effect between plumes and inter-plume regions (IPRs). Before the spectroscopic peculiarities in IPRs and plumes in polar coron...

  1. Estimation of Enceladus Plume Density Using Cassini Flight Data

    Science.gov (United States)

    Wang, Eric K.; Lee, Allan Y.

    2011-01-01

    The Cassini spacecraft was launched on October 15, 1997 by a Titan 4B launch vehicle. After an interplanetary cruise of almost seven years, it arrived at Saturn on June 30, 2004. In 2005, Cassini completed three flybys of Enceladus, a small, icy satellite of Saturn. Observations made during these flybys confirmed the existence of water vapor plumes in the south polar region of Enceladus. Five additional low-altitude flybys of Enceladus were successfully executed in 2008-9 to better characterize these watery plumes. During some of these Enceladus flybys, the spacecraft attitude was controlled by a set of three reaction wheels. When the disturbance torque imparted on the spacecraft was predicted to exceed the control authority of the reaction wheels, thrusters were used to control the spacecraft attitude. Using telemetry data of reaction wheel rates or thruster on-times collected from four low-altitude Enceladus flybys (in 2008-10), one can reconstruct the time histories of the Enceladus plume jet density. The 1 sigma uncertainty of the estimated density is 5.9-6.7% (depending on the density estimation methodology employed). These plume density estimates could be used to confirm measurements made by other onboard science instruments and to support the modeling of Enceladus plume jets.

  2. Pyroxenite in the Galapagos plume source at 65 Ma

    Science.gov (United States)

    Whalen, W. T.; Gazel, E.; Vidito, C. A.; Herzberg, C. T.; Class, C.; Bizimis, M.; Alvarado-Induni, G.

    2013-12-01

    Mantle plumes originate from boundary layers below the upper mantle. Their surface expressions as hotspot tracks have been linked to voluminous outpourings of lava in the form of large igneous provinces. The Galapagos hotspot has been active since ~90 Ma and the oldest lavas of its associated submarine ridge have been dated to ~14 Ma, subducting at the Middle America Trench, off Costa Rica. The Galapagos plume head magmatic production is preserved as the Caribbean Large Igneous Province (CLIP). A series of 15-65 Ma accreted Galapagos paleo-ridges and islands/seamounts are accreted in the Pacific coast of Costa Rica and Panama. One of these accreted terranes, the Quepos block on the west coast of Costa Rica is an ancient, ~65 Ma Galapagos island. Olivine phenocrysts from Quepos picrites have elevated Ni and low Ca and Mn and Fe/Mn indicative of a dominant pyroxenite source component while CLIP samples are dominated by a peridotite source. The mantle potential temperature (max) of the plume changed from ~1650 to ~1550 C at 65 Ma. This change correlates with the first appearance of the pyroxenite component and an EMII signature (Northern Galapagos Domain) in the Galapagos plume. A relatively dense pyroxenite component may provide a mechanism for the change in Tp due to its effect on the plume's bouyancy. Alternatively, the pyroxenite component was diluted by high peridotite melt fraction during the massive production of the CLIP.

  3. Effects of Boundary Conditions on Near Field Plasma Plume Simulations

    Science.gov (United States)

    Boyd, Iain

    2004-11-01

    The successful development of various types of electric propulsion devices is providing the need for accurate assessment of integration effects generated by the interaction of the plasma plumes of these thrusters with the host spacecraft. Assessment of spacecraft interaction effects in ground based laboratory facilities is inadequate due to the technical difficulties involved in accurately recreating the near vacuum ambient conditions experienced in space. This situation therefore places a heavy demand on computational modeling of plasma plume phenomena. Recently (Boyd and Yim, Journal of Applied Physics, Vol. 95, 2004, pp. 4575-5484) a hybrid model of the near field of the plume of a Hall thruster was reported in which the heavy species are modeled using particles and the electrons are modeled using a detailed fluid description. The present study continues the model development and assessment by considering the sensitivity of computed results to different types of boundary conditions that must be formulated for the thruster exit, for the cathode exit, for the thruster walls, and for the plume far field. The model is assessed through comparison of its predictions with several sets of experimental data measured in the plume of the BHT-200 Hall thruster.

  4. Calculating the probability of injected carbon dioxide plumes encountering faults

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, P.D.

    2011-04-01

    One of the main concerns of storage in saline aquifers is leakage via faults. In the early stages of site selection, site-specific fault coverages are often not available for these aquifers. This necessitates a method using available fault data to estimate the probability of injected carbon dioxide encountering and migrating up a fault. The probability of encounter can be calculated from areal fault density statistics from available data, and carbon dioxide plume dimensions from numerical simulation. Given a number of assumptions, the dimension of the plume perpendicular to a fault times the areal density of faults with offsets greater than some threshold of interest provides probability of the plume encountering such a fault. Application of this result to a previously planned large-scale pilot injection in the southern portion of the San Joaquin Basin yielded a 3% and 7% chance of the plume encountering a fully and half seal offsetting fault, respectively. Subsequently available data indicated a half seal-offsetting fault at a distance from the injection well that implied a 20% probability of encounter for a plume sufficiently large to reach it.

  5. Search for Ozone Plumes over Western Long Island Sound, NY, CT

    Science.gov (United States)

    Cotten, D. E.; Austin, S.; Johnson, L. P.; Johnson, R.; Marchese, P.; Guerrero, J.; Reid, J.; Cotten, C. D.; Cotten, G. D.

    2007-12-01

    A search has been conducted for near-surface ozone plumes extending roughly northeastward from New York City, by employing ozonesondes carried by a boat on western Long Island Sound. This water-borne search pattern avoids the local sources densely distributed on land in the suburban counties and small cities in Westchester, Long Island, and Connecticut. The observations are done using ECC 2Z ozonesondes and Vaisala 80-15 radiosondes normally used for ozone profiles in the troposphere and stratosphere. The sensors were placed forward on the boat, to avoid ozone produced by the boat's own engine. Several straight traverses were made between the north and south shores. These were extended into bays and harbors where it was possible without much bending of the trajectory, in order to lengthen the runs and carry them close to shore. These runs proceeded (somewhat diagonally, zig-zagging) from west to east, followed by a straight 30 mile direct radial transit approaching New York City southwestward. The data has been examined to look for aligned peaks on the transverse runs at the various radial distances from New York City, which would indicate the existence of ozone plumes transported northeastward from the city. Concentration variation in the radial direction was also examined. The study is expected to be extended to eastern Long Island Sound and the New York bight, south of Long Island

  6. A QSAR/QSTR Study on the Environmental Health Impact by the Rocket Fuel 1,1-Dimethyl Hydrazine and its Transformation Products

    Directory of Open Access Journals (Sweden)

    Lars Carlsen

    2008-01-01

    Full Text Available QSAR/QSTR modelling constitutes an attractive approach to preliminary assessment of the impact on environmental health by a primary pollutant and the suite of transformation products that may be persistent in and toxic to the environment. The present paper studies the impact on environmental health by residuals of the rocket fuel 1,1-dimethyl hydrazine (heptyl and its transformation products. The transformation products, comprising a variety of nitrogen containing compounds are suggested all to possess a significant migration potential. In all cases the compounds were found being rapidly biodegradable. However, unexpected low microbial activity may cause significant changes. None of the studied compounds appear to be bioaccumulating. Apart from substances with an intact hydrazine structure or hydrazone structure the transformation products in general display rather low environmental toxicities. Thus, it is concluded that apparently further attention should be given to tri- and tetramethyl hydrazine and 1-formyl 2,2-dimethyl hydrazine as well as to the hydrazones of formaldehyde and acetaldehyde as these five compounds may contribute to the overall environmental toxicity of residual rocket fuel and its transformation products.

  7. A QSAR/QSTR Study on the Environmental Health Impact by the Rocket Fuel 1,1-Dimethyl Hydrazine and its Transformation Products.

    Science.gov (United States)

    Carlsen, Lars; Kenessov, Bulat N; Batyrbekova, Svetlana Ye

    2008-07-18

    QSAR/QSTR modelling constitutes an attractive approach to preliminary assessment of the impact on environmental health by a primary pollutant and the suite of transformation products that may be persistent in and toxic to the environment. The present paper studies the impact on environmental health by residuals of the rocket fuel 1,1-dimethyl hydrazine (heptyl) and its transformation products. The transformation products, comprising a variety of nitrogen containing compounds are suggested all to possess a significant migration potential. In all cases the compounds were found being rapidly biodegradable. However, unexpected low microbial activity may cause significant changes. None of the studied compounds appear to be bioaccumulating.Apart from substances with an intact hydrazine structure or hydrazone structure the transformation products in general display rather low environmental toxicities. Thus, it is concluded that apparently further attention should be given to tri- and tetramethyl hydrazine and 1-formyl 2,2-dimethyl hydrazine as well as to the hydrazones of formaldehyde and acetaldehyde as these five compounds may contribute to the overall environmental toxicity of residual rocket fuel and its transformation products.

  8. Infrared spectra of hydrazine and products of its reactions with HF, F/sub 2/, and O/sub 3/ in solid argon

    Energy Technology Data Exchange (ETDEWEB)

    Lascola, R.; Withnall, R.; Andrews, L.

    1988-02-24

    Hydrazine, N/sub 2/H/sub 4/, and its reactions with HF, F/sub 2/, and O/sub 3/ have been studied in an argon matrix. Vibrational assignments have been made for hydrazine, including clarification of the /nu//sub 6/, /nu//sub 10/, and 2/nu//sub 7/ bands. Complexation of N/sub 2/H/sub 4/ with HF produced a strong band at 2928 cm/sup /minus/1/ (/nu//sub s/(HF)) and sharp bands at 940 and 922 cm/sup /minus/1/ (/nu//sub 1/(HF)), as well as several perturbed N/sub 2/H/sub 4/ submolecule absorptions; the frequencies of these bands suggest a chelated structure similar to that for the NH/sub 2/OH-HF complex. Hydrazine and fluorine reacted during deposition to give the NH/sub 2/NHF-HF complex (/nu//sub s/ = 3113 cm/sup /minus/1/, /nu//sub 1/ = 726, 680 cm/sup /minus/1/). Reaction of hydrazine and ozone produced hydroxyhydrazine, NH/sub 2/NHOH, and minor products during deposition; photolysis increased the yield of hydroxyhydrazine. Evidence for an intramolecular hydrogen bond was found for NH/sub 2/NHOH. This matrix study presents the first spectroscopic evidence for both NH/sub 2/NHF and NH/sub 2/NHOH. 32 references, 3 figures, 4 tables.

  9. Preparation of Sulphur-containing Aromatic Amines by Reduction of the Corresponding Aromatic Nitro Compounds with Hydrazine Hydrate over Iron Oxide Hydroxide Catalyst

    Institute of Scientific and Technical Information of China (English)

    Qi Xun SHI; Rong Wen LU; Zhu Xia ZHANG; De Feng ZHAO

    2006-01-01

    Sulphur-containing aromatic nitro compounds were rapidly reduced to the corresponding amines in high yields by employing hydrazine hydrate as a hydrogen donor in the presence of iron oxide hydroxide catalyst. It was worth noting that the catalyst exhibited extremely high activity. The reduction could be completed within 20-50 min and the yields were up to 97-99 %.

  10. Photoconversion of 4-nitrophenol in the presence of hydrazine with AgNPs-TiO{sub 2} nanoparticles prepared by the sol–gel method

    Energy Technology Data Exchange (ETDEWEB)

    Hernández-Gordillo, Agileo, E-mail: agileo12@hotmail.com [División de Materiales Avanzados, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055 Col. Lomas 4a. sección, C.P. 78216 San Luis Potosí, SLP, México (Mexico); CIIEMAD, Instituto Politécnico Nacional, Calle 30 de Junio de 1520 s/n, Barrio la Laguna Ticomán, C.P. 07340, Del. Gustavo A. Madero, DF, México (Mexico); Arroyo, Missael [División de Materiales Avanzados, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055 Col. Lomas 4a. sección, C.P. 78216 San Luis Potosí, SLP, México (Mexico); Zanella, R. [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Circuito Exterior S/N, Ciudad Universitaria, A.P. 70-186, Delegación Coyoacán, C.P. 04510 México, DF, México (Mexico); and others

    2014-03-01

    Graphical abstract: - Highlights: • AgNPs are well dispersed on TiO{sub 2} semiconductor surface. • TiO{sub 2} with 1.5 wt% of Ag{sup 0} is the most photoactive for the 4-nitrophenol conversion. • High conversion of 4-nitrofenol to 4-aminophenol was achieved with hydrazine. • Enhanced photoactivity of Ag-TiO{sub 2} is associated with the ability to oxidize hydrazine. - Abstract: The photocatalytic properties of functionalized TiO{sub 2} with silver nanoparticles (AgNPs) for the conversion of 4-nitrophenol to 4-aminophenol in the presence of hydrazine were investigated. The TiO{sub 2} semiconductor synthesized by the sol–gel method was functionalized with AgNPs at different loadings, and their structural and optical properties were characterized by several techniques. The functionalized TiO{sub 2} with 1.5 wt% AgNPs presented the highest photocatalytic activity for the conversion of 4-nitrophenol with appropriate hydrazine concentrations (0.5 M). The photoefficiency enhancement under UV light irradiation was attributed to the electron transfer from the TiO{sub 2} semiconductor surface to the adsorbed acceptor reactant (4-nitrophenol) through the deposited AgNPs.

  11. MICROWAVE-ASSISTED CYCLOCONDENSATION OF HYDRAZINE DERIVATIVES WITH ALKYL DIHALIDES OR DITOSYLATES IN AQUEOUS MEDIA: SYNTHESES OF PYRAZOLE, PYRAZOLIDINE AND PHTHALAZINE DERIVATIVES

    Science.gov (United States)

    Direct synthesis of 4,5-dihydro-pyrazole, pyrazolidine, and 1,2-dihydro-phthalazine derivatives via double alkylation of hydrazines by alkyl dihalides or ditosylates were accomplished in aqueous media under microwave irradiation conditions; the environmentally friendlier chemical...

  12. Study of Plume Characteristics of a Stationary Plasma Thruster

    Institute of Scientific and Technical Information of China (English)

    QIAN Zhong; WANG Pingyang; DU Zhaohui; KANG Xiaolu

    2008-01-01

    Electron density and temperature of the plume are measured by a double Langmuir probe in an experimental chamber.A numerical model based on both particle-in-cell scheme and direct simulation Monte Carlo hybrid method is developed to simulate the flow field of plume.The equation for plasma potential is solved by alternative direction implicit technique. The simulation is verified by comparing the computational results with the measured data.The study indicates that the electron temperature of flow field is about 2 eV and the electron density is about 2.5 × 1016 ~ 5 × 1015 m-3 at the central line with a distance of 0.3 ~ 1.0 m downstream of the thruster exit.The model can well predict the flow field parameters of the steady plume.The efforts of this paper are referable for further investigation.

  13. An analytical and experimental investigation of resistojet plumes

    Science.gov (United States)

    Zana, Lynnette M.; Hoffman, David J.; Breyley, Loranell R.; Serafini, John S.

    1987-01-01

    As a part of the electrothermal propulsion plume research program at the NASA Lewis Research Center, efforts have been initiated to analytically and experimentally investigate the plumes of resistojet thrusters. The method of Simons for the prediction of rocket exhaust plumes is developed for the resistojet. Modifications are made to the source flow equations to account for the increased effects of the relatively large nozzle boundary layer. Additionally, preliminary mass flux measurements of a laboratory resistojet using CO2 propellant at 298 K have been obtained with a cryogenically cooled quartz crystal microbalance (QCM). There is qualitative agreement between analysis and experiment, at least in terms of the overall number density shape functions in the forward flux region.

  14. Turbulent Boyant Jets and Plumes in Flowing Ambient Environments

    DEFF Research Database (Denmark)

    Chen, Hai-Bo

    Turbulent buoyant jets and plumes in flowing ambient environments have been studied theoretically and experimentally. The mechanics of turbulent buoyant jets and plumes in flowing ambients have been discussed. Dimensional analysis was employed to investigate the mean behaviour of the turbulent...... and the stage of plume. The stability criteria for the upstream wedge created by the submerged turbulent buoyant jet were established by applying the Bernoulli equations for a two-dimensional problem and by considering the front velocity driven by the buoyancy force for a three-dimensional problem...... in a crossflowing environment, have been presented and successfully correlated using momentum and buoyancy fluxes and length scales. The analysis demonstrates that the experimental data on the jet trajectories and dilutions can be well correlated using the momentum or buoyancy fluxes and length scales, depending...

  15. Electrical charging of ash in Icelandic volcanic plumes

    CERN Document Server

    Aplin, Karen L; Nicoll, Keri A

    2014-01-01

    The existence of volcanic lightning and alteration of the atmospheric potential gradient in the vicinity of near-vent volcanic plumes provides strong evidence for the charging of volcanic ash. More subtle electrical effects are also visible in balloon soundings of distal volcanic plumes. Near the vent, some proposed charging mechanisms are fractoemission, triboelectrification, and the so-called "dirty thunderstorm" mechanism, which is where ash and convective clouds interact electrically to enhance charging. Distant from the vent, a self-charging mechanism, probably triboelectrification, has been suggested to explain the sustained low levels of charge observed on a distal plume. Recent research by Houghton et al. (2013) linked the self-charging of volcanic ash to the properties of the particle size distribution, observing that a highly polydisperse ash distribution would charge more effectively than a monodisperse one. Natural radioactivity in some volcanic ash could also contribute to self-charging of volcan...

  16. Cassini detection of Enceladus' cold water-group plume ionosphere

    Science.gov (United States)

    Tokar, R. L.; Johnson, R. E.; Thomsen, M. F.; Wilson, R. J.; Young, D. T.; Crary, F. J.; Coates, A. J.; Jones, G. H.; Paty, C. S.

    2009-07-01

    This study reports direct detection by the Cassini plasma spectrometer of freshly-produced water-group ions (O+, OH+, H2O+, H3O+) and heavier water dimer ions (HxO2)+ very close to Enceladus where the plasma begins to emerge from the plume. The data were obtained during two close (52 and 25 km) flybys of Enceladus in 2008 and are similar to ion data in cometary comas. The ions are observed in detectors looking in the Cassini ram direction exhibiting energies consistent with the Cassini speed, indicative of a nearly stagnant plasma flow in the plume. North of Enceladus the plasma slowing commences about 4 to 6 Enceladus radii away, while south of Enceladus signatures of the plasma interaction with the plume are detected 22 Enceladus radii away.

  17. Tidally induced lateral dispersion of the Storfjorden overflow plume

    Directory of Open Access Journals (Sweden)

    F. Wobus

    2013-10-01

    Full Text Available We investigate the flow of brine-enriched shelf water from Storfjorden (Svalbard into Fram Strait and onto the western Svalbard Shelf using a regional set-up of NEMO-SHELF, a 3-D numerical ocean circulation model. The model is set up with realistic bathymetry, atmospheric forcing, open boundary conditions and tides. The model has 3 km horizontal resolution and 50 vertical levels in the sh-coordinate system which is specially designed to resolve bottom boundary layer processes. In a series of modelling experiments we focus on the influence of tides on the propagation of the dense water plume by comparing results from tidal and non-tidal model runs. Comparisons of non-tidal to tidal simulations reveal a hotspot of tidally induced horizontal diffusion leading to the lateral dispersion of the plume at the southernmost headland of Spitsbergen which is in close proximity to the plume path. As a result the lighter fractions in the diluted upper layer of the plume are drawn into the shallow coastal current that carries Storfjorden water onto the western Svalbard Shelf, while the dense bottom layer continues to sink down the slope. This bifurcation of the plume into a diluted shelf branch and a dense downslope branch is enhanced by tidally induced shear dispersion at the headland. Tidal effects at the headland are shown to cause a net reduction in the downslope flux of Storfjorden water into the deep Fram Strait. This finding contrasts previous results from observations of a dense plume on a different shelf without abrupt topography.

  18. Satellite detection of wastewater diversion plumes in Southern California

    Science.gov (United States)

    Gierach, Michelle M.; Holt, Benjamin; Trinh, Rebecca; Jack Pan, B.; Rains, Christine

    2017-02-01

    Multi-sensor satellite observations proved useful in detecting surfacing wastewater plumes during the 2006 Hyperion Treatment Plant (HTP) and 2012 Orange County Sanitation District (OCSD) wastewater diversion events in Southern California. Satellite sensors were capable of detecting biophysical signatures associated with the wastewater, compared to ambient ocean waters, enabling monitoring of environmental impacts over a greater spatial extent than in situ sampling alone. Thermal satellite sensors measured decreased sea surface temperatures (SSTs) associated with the surfacing plumes. Ocean color satellite sensors did not measure a distinguishable biological response in terms of chlorophyll-a (chl-a) concentrations during the short lived, three-day long, 2006 HTP diversion. A period of decreased chl-a concentration was observed during the three-week long 2012 OCSD diversion, likely in association with enhanced chlorination of the discharged wastewater that suppressed the phytoplankton response and/or significant uptake by heterotrophic bacteria. Synthetic aperture radar (SAR) satellite data were able to identify and track the 2006 HTP wastewater plume through changes in surface roughness related to the oily components of the treated surfacing wastewater. Overall, it was found that chl-a and SST values must have differences of at least 1 mg m-3 and 0.5 °C, respectively, in comparison with adjacent waters for wastewater plumes and their biophysical impact to be detectable from satellite. For a wastewater plume to be identifiable in SAR imagery, wind speeds must range between ∼3 and 8 m s-1. The findings of this study illustrate the benefit of utilizing multiple satellite sensors to monitor the rapidly changing environmental response to surfacing wastewater plumes, and can help inform future wastewater diversions in coastal areas.

  19. IASI measurements of reactive trace species in biomass burning plumes

    Directory of Open Access Journals (Sweden)

    P.-F. Coheur

    2009-08-01

    Full Text Available This work presents observations of a series of short-lived species in biomass burning plumes from the Infrared Atmospheric Sounding Interferometer (IASI, launched onboard the MetOp-A platform in October 2006. The strong fires that have occurred in the Mediterranean Basin – and particularly Greece – in August 2007, and those in Southern Siberia and Eastern Mongolia in the early spring of 2008 are selected to support the analyses. We show that the IASI infrared spectra in these fire plumes contain distinctive signatures of ammonia (NH3, ethene (C2H4, methanol (CH3OH and formic acid (HCOOH in the atmospheric window between 800 and 1200 cm−1, with some noticeable differences between the plumes. Peroxyacetyl nitrate (CH3COOONO2, abbreviated as PAN was also observed with good confidence in some plumes and a tentative assignment of a broadband absorption spectral feature to acetic acid (CH3COOH is made. For several of these species these are the first reported measurements made from space in nadir geometry. The IASI measurements are analyzed for plume height and concentration distributions of NH3, C2H4 and CH3OH. The Greek fires are studied in greater detail for the days associated with the largest emissions. In addition to providing information on the spatial extent of the plume, the IASI retrievals allow an estimate of the total mass emissions for NH3, C2H4 and CH3OH. Enhancement ratios are calculated for the latter relative to carbon monoxide (CO, giving insight in the chemical processes occurring during the transport, the first day after the emission.

  20. Aerosol nucleation in coal-fired power-plant plumes

    Science.gov (United States)

    Stevens, Robin; Lonsdale, Chantelle; Brock, Charles; Makar, Paul; Knipping, Eladio; Reed, Molly; Crawford, James; Holloway, John; Ryerson, Tim; Huey, L. Greg; Nowak, John; Pierce, Jeffrey

    2013-05-01

    New-particle nucleation within coal-fired power-plant plumes can have large effects on particle number concentrations, particularly near source regions, with implications for human health and climate. In order to resolve the formation and growth of particles in these plumes, we have integrated TwO-Moment Aerosol Sectional (TOMAS) microphysics in the System for Atmospheric Modelling (SAM), a large-eddy simulation/cloud-resolving model (LES/CRM). We have evaluated this model against aircraft observations for three case studies, and the model reproduces well the major features of each case. Using this model, we have shown that meteorology and background aerosol concentrations can have strong effects on new-particle formation and growth in coal-fired power-plant plumes, even if emissions are held constant. We subsequently used the model to evaluate the effects of SO2 and NOx pollution controls on newparticle formation in coal-fired power-plant plumes. We found that strong reductions in NOx emissions without concurrent reductions in SO2 emissions may increase new-particle formation, due to increases in OH formation within the plume. We predicted the change in new-particle formation due to changes in emissions between 1997 and 2010 for 330 coal-fired power plants in the US, and we found a median decrease of 19% in new-particle formation. However, the magnitude and sign of the aerosol changes depend greatly on the relative reductions in NOx and SO2 emissions in each plant. More extensive plume measurements for a range of emissions of SO2 and NOx and in varying background aerosol conditions are needed, however, to better quantify these effects.